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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
2 * kernel/sched.c
3 *
4 * Kernel scheduler and related syscalls
5 *
6 * Copyright (C) 1991-2002 Linus Torvalds
7 *
8 * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and
9 * make semaphores SMP safe
10 * 1998-11-19 Implemented schedule_timeout() and related stuff
11 * by Andrea Arcangeli
12 * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar:
13 * hybrid priority-list and round-robin design with
14 * an array-switch method of distributing timeslices
15 * and per-CPU runqueues. Cleanups and useful suggestions
16 * by Davide Libenzi, preemptible kernel bits by Robert Love.
17 * 2003-09-03 Interactivity tuning by Con Kolivas.
18 * 2004-04-02 Scheduler domains code by Nick Piggin
Ingo Molnarc31f2e82007-07-09 18:52:01 +020019 * 2007-04-15 Work begun on replacing all interactivity tuning with a
20 * fair scheduling design by Con Kolivas.
21 * 2007-05-05 Load balancing (smp-nice) and other improvements
22 * by Peter Williams
23 * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith
24 * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri
Ingo Molnarb9131762008-01-25 21:08:19 +010025 * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins,
26 * Thomas Gleixner, Mike Kravetz
Linus Torvalds1da177e2005-04-16 15:20:36 -070027 */
28
29#include <linux/mm.h>
30#include <linux/module.h>
31#include <linux/nmi.h>
32#include <linux/init.h>
Ingo Molnardff06c12007-07-09 18:52:00 +020033#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070034#include <linux/highmem.h>
35#include <linux/smp_lock.h>
36#include <asm/mmu_context.h>
37#include <linux/interrupt.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080038#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070039#include <linux/completion.h>
40#include <linux/kernel_stat.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070041#include <linux/debug_locks.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070042#include <linux/security.h>
43#include <linux/notifier.h>
44#include <linux/profile.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080045#include <linux/freezer.h>
akpm@osdl.org198e2f12006-01-12 01:05:30 -080046#include <linux/vmalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <linux/blkdev.h>
48#include <linux/delay.h>
Pavel Emelyanovb4888932007-10-18 23:40:14 -070049#include <linux/pid_namespace.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050#include <linux/smp.h>
51#include <linux/threads.h>
52#include <linux/timer.h>
53#include <linux/rcupdate.h>
54#include <linux/cpu.h>
55#include <linux/cpuset.h>
56#include <linux/percpu.h>
57#include <linux/kthread.h>
58#include <linux/seq_file.h>
Nick Piggine692ab52007-07-26 13:40:43 +020059#include <linux/sysctl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070060#include <linux/syscalls.h>
61#include <linux/times.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070062#include <linux/tsacct_kern.h>
bibo maoc6fd91f2006-03-26 01:38:20 -080063#include <linux/kprobes.h>
Shailabh Nagar0ff92242006-07-14 00:24:37 -070064#include <linux/delayacct.h>
Eric Dumazet5517d862007-05-08 00:32:57 -070065#include <linux/reciprocal_div.h>
Ingo Molnardff06c12007-07-09 18:52:00 +020066#include <linux/unistd.h>
Jens Axboef5ff8422007-09-21 09:19:54 +020067#include <linux/pagemap.h>
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +010068#include <linux/hrtimer.h>
Reynes Philippe30914a52008-03-17 16:19:05 -070069#include <linux/tick.h>
Mike Travis434d53b2008-04-04 18:11:04 -070070#include <linux/bootmem.h>
Peter Zijlstraf00b45c2008-04-19 19:45:00 +020071#include <linux/debugfs.h>
72#include <linux/ctype.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
Eric Dumazet5517d862007-05-08 00:32:57 -070074#include <asm/tlb.h>
Satyam Sharma838225b2007-10-24 18:23:50 +020075#include <asm/irq_regs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070076
Gregory Haskins6e0534f2008-05-12 21:21:01 +020077#include "sched_cpupri.h"
78
Linus Torvalds1da177e2005-04-16 15:20:36 -070079/*
80 * Convert user-nice values [ -20 ... 0 ... 19 ]
81 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
82 * and back.
83 */
84#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
85#define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
86#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
87
88/*
89 * 'User priority' is the nice value converted to something we
90 * can work with better when scaling various scheduler parameters,
91 * it's a [ 0 ... 39 ] range.
92 */
93#define USER_PRIO(p) ((p)-MAX_RT_PRIO)
94#define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
95#define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
96
97/*
Ingo Molnard7876a02008-01-25 21:08:19 +010098 * Helpers for converting nanosecond timing to jiffy resolution
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 */
Eric Dumazetd6322fa2007-11-09 22:39:38 +0100100#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200102#define NICE_0_LOAD SCHED_LOAD_SCALE
103#define NICE_0_SHIFT SCHED_LOAD_SHIFT
104
Linus Torvalds1da177e2005-04-16 15:20:36 -0700105/*
106 * These are the 'tuning knobs' of the scheduler:
107 *
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +0200108 * default timeslice is 100 msecs (used only for SCHED_RR tasks).
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 * Timeslices get refilled after they expire.
110 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111#define DEF_TIMESLICE (100 * HZ / 1000)
Peter Williams2dd73a42006-06-27 02:54:34 -0700112
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200113/*
114 * single value that denotes runtime == period, ie unlimited time.
115 */
116#define RUNTIME_INF ((u64)~0ULL)
117
Eric Dumazet5517d862007-05-08 00:32:57 -0700118#ifdef CONFIG_SMP
119/*
120 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
121 * Since cpu_power is a 'constant', we can use a reciprocal divide.
122 */
123static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
124{
125 return reciprocal_divide(load, sg->reciprocal_cpu_power);
126}
127
128/*
129 * Each time a sched group cpu_power is changed,
130 * we must compute its reciprocal value
131 */
132static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
133{
134 sg->__cpu_power += val;
135 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
136}
137#endif
138
Ingo Molnare05606d2007-07-09 18:51:59 +0200139static inline int rt_policy(int policy)
140{
Roel Kluin3f33a7c2008-05-13 23:44:11 +0200141 if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR))
Ingo Molnare05606d2007-07-09 18:51:59 +0200142 return 1;
143 return 0;
144}
145
146static inline int task_has_rt_policy(struct task_struct *p)
147{
148 return rt_policy(p->policy);
149}
150
Linus Torvalds1da177e2005-04-16 15:20:36 -0700151/*
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200152 * This is the priority-queue data structure of the RT scheduling class:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153 */
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200154struct rt_prio_array {
155 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
Gregory Haskins45c01e82008-05-12 21:20:41 +0200156 struct list_head xqueue[MAX_RT_PRIO]; /* exclusive queue */
157 struct list_head squeue[MAX_RT_PRIO]; /* shared queue */
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200158};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700159
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200160struct rt_bandwidth {
Ingo Molnarea736ed2008-03-25 13:51:45 +0100161 /* nests inside the rq lock: */
162 spinlock_t rt_runtime_lock;
163 ktime_t rt_period;
164 u64 rt_runtime;
165 struct hrtimer rt_period_timer;
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200166};
167
168static struct rt_bandwidth def_rt_bandwidth;
169
170static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
171
172static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
173{
174 struct rt_bandwidth *rt_b =
175 container_of(timer, struct rt_bandwidth, rt_period_timer);
176 ktime_t now;
177 int overrun;
178 int idle = 0;
179
180 for (;;) {
181 now = hrtimer_cb_get_time(timer);
182 overrun = hrtimer_forward(timer, now, rt_b->rt_period);
183
184 if (!overrun)
185 break;
186
187 idle = do_sched_rt_period_timer(rt_b, overrun);
188 }
189
190 return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
191}
192
193static
194void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
195{
196 rt_b->rt_period = ns_to_ktime(period);
197 rt_b->rt_runtime = runtime;
198
Peter Zijlstraac086bc2008-04-19 19:44:58 +0200199 spin_lock_init(&rt_b->rt_runtime_lock);
200
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200201 hrtimer_init(&rt_b->rt_period_timer,
202 CLOCK_MONOTONIC, HRTIMER_MODE_REL);
203 rt_b->rt_period_timer.function = sched_rt_period_timer;
204 rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
205}
206
207static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
208{
209 ktime_t now;
210
211 if (rt_b->rt_runtime == RUNTIME_INF)
212 return;
213
214 if (hrtimer_active(&rt_b->rt_period_timer))
215 return;
216
217 spin_lock(&rt_b->rt_runtime_lock);
218 for (;;) {
219 if (hrtimer_active(&rt_b->rt_period_timer))
220 break;
221
222 now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
223 hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
224 hrtimer_start(&rt_b->rt_period_timer,
225 rt_b->rt_period_timer.expires,
226 HRTIMER_MODE_ABS);
227 }
228 spin_unlock(&rt_b->rt_runtime_lock);
229}
230
231#ifdef CONFIG_RT_GROUP_SCHED
232static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
233{
234 hrtimer_cancel(&rt_b->rt_period_timer);
235}
236#endif
237
Heiko Carstens712555e2008-04-28 11:33:07 +0200238/*
239 * sched_domains_mutex serializes calls to arch_init_sched_domains,
240 * detach_destroy_domains and partition_sched_domains.
241 */
242static DEFINE_MUTEX(sched_domains_mutex);
243
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100244#ifdef CONFIG_GROUP_SCHED
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200245
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -0700246#include <linux/cgroup.h>
247
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200248struct cfs_rq;
249
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100250static LIST_HEAD(task_groups);
251
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200252/* task group related information */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200253struct task_group {
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100254#ifdef CONFIG_CGROUP_SCHED
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -0700255 struct cgroup_subsys_state css;
256#endif
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100257
258#ifdef CONFIG_FAIR_GROUP_SCHED
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200259 /* schedulable entities of this group on each cpu */
260 struct sched_entity **se;
261 /* runqueue "owned" by this group on each cpu */
262 struct cfs_rq **cfs_rq;
263 unsigned long shares;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100264#endif
265
266#ifdef CONFIG_RT_GROUP_SCHED
267 struct sched_rt_entity **rt_se;
268 struct rt_rq **rt_rq;
269
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200270 struct rt_bandwidth rt_bandwidth;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100271#endif
Srivatsa Vaddagiri6b2d7702008-01-25 21:08:00 +0100272
Srivatsa Vaddagiriae8393e2007-10-29 21:18:11 +0100273 struct rcu_head rcu;
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100274 struct list_head list;
Peter Zijlstraf473aa52008-04-19 19:45:00 +0200275
276 struct task_group *parent;
277 struct list_head siblings;
278 struct list_head children;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200279};
280
Dhaval Giani354d60c2008-04-19 19:44:59 +0200281#ifdef CONFIG_USER_SCHED
Peter Zijlstraeff766a2008-04-19 19:45:00 +0200282
283/*
284 * Root task group.
285 * Every UID task group (including init_task_group aka UID-0) will
286 * be a child to this group.
287 */
288struct task_group root_task_group;
289
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100290#ifdef CONFIG_FAIR_GROUP_SCHED
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200291/* Default task group's sched entity on each cpu */
292static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
293/* Default task group's cfs_rq on each cpu */
294static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +0200295#endif /* CONFIG_FAIR_GROUP_SCHED */
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100296
297#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100298static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity);
299static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp;
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +0200300#endif /* CONFIG_RT_GROUP_SCHED */
301#else /* !CONFIG_FAIR_GROUP_SCHED */
Peter Zijlstraeff766a2008-04-19 19:45:00 +0200302#define root_task_group init_task_group
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +0200303#endif /* CONFIG_FAIR_GROUP_SCHED */
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100304
Peter Zijlstra8ed36992008-02-13 15:45:39 +0100305/* task_group_lock serializes add/remove of task groups and also changes to
Srivatsa Vaddagiriec2c5072008-01-25 21:07:59 +0100306 * a task group's cpu shares.
307 */
Peter Zijlstra8ed36992008-02-13 15:45:39 +0100308static DEFINE_SPINLOCK(task_group_lock);
Srivatsa Vaddagiriec2c5072008-01-25 21:07:59 +0100309
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100310#ifdef CONFIG_FAIR_GROUP_SCHED
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100311#ifdef CONFIG_USER_SCHED
Ingo Molnar0eab9142008-01-25 21:08:19 +0100312# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +0200313#else /* !CONFIG_USER_SCHED */
Srivatsa Vaddagiri93f992c2008-01-25 21:07:59 +0100314# define INIT_TASK_GROUP_LOAD NICE_0_LOAD
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +0200315#endif /* CONFIG_USER_SCHED */
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200316
Miao Xiecb4ad1f2008-04-28 12:54:56 +0800317/*
Lai Jiangshan2e084782008-06-12 16:42:58 +0800318 * A weight of 0 or 1 can cause arithmetics problems.
319 * A weight of a cfs_rq is the sum of weights of which entities
320 * are queued on this cfs_rq, so a weight of a entity should not be
321 * too large, so as the shares value of a task group.
Miao Xiecb4ad1f2008-04-28 12:54:56 +0800322 * (The default weight is 1024 - so there's no practical
323 * limitation from this.)
324 */
Peter Zijlstra18d95a22008-04-19 19:45:00 +0200325#define MIN_SHARES 2
Lai Jiangshan2e084782008-06-12 16:42:58 +0800326#define MAX_SHARES (1UL << 18)
Peter Zijlstra18d95a22008-04-19 19:45:00 +0200327
Srivatsa Vaddagiri93f992c2008-01-25 21:07:59 +0100328static int init_task_group_load = INIT_TASK_GROUP_LOAD;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100329#endif
330
331/* Default task group.
332 * Every task in system belong to this group at bootup.
333 */
Mike Travis434d53b2008-04-04 18:11:04 -0700334struct task_group init_task_group;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200335
336/* return group to which a task belongs */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200337static inline struct task_group *task_group(struct task_struct *p)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200338{
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200339 struct task_group *tg;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200340
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100341#ifdef CONFIG_USER_SCHED
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200342 tg = p->user->tg;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100343#elif defined(CONFIG_CGROUP_SCHED)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -0700344 tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id),
345 struct task_group, css);
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200346#else
Ingo Molnar41a2d6c2007-12-05 15:46:09 +0100347 tg = &init_task_group;
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200348#endif
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200349 return tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200350}
351
352/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100353static inline void set_task_rq(struct task_struct *p, unsigned int cpu)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200354{
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100355#ifdef CONFIG_FAIR_GROUP_SCHED
Dmitry Adamushkoce96b5a2007-11-15 20:57:40 +0100356 p->se.cfs_rq = task_group(p)->cfs_rq[cpu];
357 p->se.parent = task_group(p)->se[cpu];
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100358#endif
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100359
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100360#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100361 p->rt.rt_rq = task_group(p)->rt_rq[cpu];
362 p->rt.parent = task_group(p)->rt_se[cpu];
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100363#endif
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200364}
365
366#else
367
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100368static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200369
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100370#endif /* CONFIG_GROUP_SCHED */
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200371
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200372/* CFS-related fields in a runqueue */
373struct cfs_rq {
374 struct load_weight load;
375 unsigned long nr_running;
376
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200377 u64 exec_clock;
Ingo Molnare9acbff2007-10-15 17:00:04 +0200378 u64 min_vruntime;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200379
380 struct rb_root tasks_timeline;
381 struct rb_node *rb_leftmost;
Peter Zijlstra4a55bd52008-04-19 19:45:00 +0200382
383 struct list_head tasks;
384 struct list_head *balance_iterator;
385
386 /*
387 * 'curr' points to currently running entity on this cfs_rq.
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200388 * It is set to NULL otherwise (i.e when none are currently running).
389 */
Peter Zijlstraaa2ac252008-03-14 21:12:12 +0100390 struct sched_entity *curr, *next;
Peter Zijlstraddc97292007-10-15 17:00:10 +0200391
392 unsigned long nr_spread_over;
393
Ingo Molnar62160e32007-10-15 17:00:03 +0200394#ifdef CONFIG_FAIR_GROUP_SCHED
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200395 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
396
Ingo Molnar41a2d6c2007-12-05 15:46:09 +0100397 /*
398 * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200399 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
400 * (like users, containers etc.)
401 *
402 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
403 * list is used during load balance.
404 */
Ingo Molnar41a2d6c2007-12-05 15:46:09 +0100405 struct list_head leaf_cfs_rq_list;
406 struct task_group *tg; /* group that "owns" this runqueue */
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200407#endif
408};
409
410/* Real-Time classes' related field in a runqueue: */
411struct rt_rq {
412 struct rt_prio_array active;
Steven Rostedt63489e42008-01-25 21:08:03 +0100413 unsigned long rt_nr_running;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100414#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100415 int highest_prio; /* highest queued rt task prio */
416#endif
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100417#ifdef CONFIG_SMP
Gregory Haskins73fe6aa2008-01-25 21:08:07 +0100418 unsigned long rt_nr_migratory;
Gregory Haskinsa22d7fc2008-01-25 21:08:12 +0100419 int overloaded;
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100420#endif
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100421 int rt_throttled;
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100422 u64 rt_time;
Peter Zijlstraac086bc2008-04-19 19:44:58 +0200423 u64 rt_runtime;
Ingo Molnarea736ed2008-03-25 13:51:45 +0100424 /* Nests inside the rq lock: */
Peter Zijlstraac086bc2008-04-19 19:44:58 +0200425 spinlock_t rt_runtime_lock;
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100426
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100427#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra23b0fdf2008-02-13 15:45:39 +0100428 unsigned long rt_nr_boosted;
429
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100430 struct rq *rq;
431 struct list_head leaf_rt_rq_list;
432 struct task_group *tg;
433 struct sched_rt_entity *rt_se;
434#endif
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200435};
436
Gregory Haskins57d885f2008-01-25 21:08:18 +0100437#ifdef CONFIG_SMP
438
439/*
440 * We add the notion of a root-domain which will be used to define per-domain
Ingo Molnar0eab9142008-01-25 21:08:19 +0100441 * variables. Each exclusive cpuset essentially defines an island domain by
442 * fully partitioning the member cpus from any other cpuset. Whenever a new
Gregory Haskins57d885f2008-01-25 21:08:18 +0100443 * exclusive cpuset is created, we also create and attach a new root-domain
444 * object.
445 *
Gregory Haskins57d885f2008-01-25 21:08:18 +0100446 */
447struct root_domain {
448 atomic_t refcount;
449 cpumask_t span;
450 cpumask_t online;
Gregory Haskins637f5082008-01-25 21:08:18 +0100451
Ingo Molnar0eab9142008-01-25 21:08:19 +0100452 /*
Gregory Haskins637f5082008-01-25 21:08:18 +0100453 * The "RT overload" flag: it gets set if a CPU has more than
454 * one runnable RT task.
455 */
456 cpumask_t rto_mask;
Ingo Molnar0eab9142008-01-25 21:08:19 +0100457 atomic_t rto_count;
Gregory Haskins6e0534f2008-05-12 21:21:01 +0200458#ifdef CONFIG_SMP
459 struct cpupri cpupri;
460#endif
Gregory Haskins57d885f2008-01-25 21:08:18 +0100461};
462
Gregory Haskinsdc938522008-01-25 21:08:26 +0100463/*
464 * By default the system creates a single root-domain with all cpus as
465 * members (mimicking the global state we have today).
466 */
Gregory Haskins57d885f2008-01-25 21:08:18 +0100467static struct root_domain def_root_domain;
468
469#endif
470
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200471/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700472 * This is the main, per-CPU runqueue data structure.
473 *
474 * Locking rule: those places that want to lock multiple runqueues
475 * (such as the load balancing or the thread migration code), lock
476 * acquire operations must be ordered by ascending &runqueue.
477 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700478struct rq {
Ingo Molnard8016492007-10-18 21:32:55 +0200479 /* runqueue lock: */
480 spinlock_t lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481
482 /*
483 * nr_running and cpu_load should be in the same cacheline because
484 * remote CPUs use both these fields when doing load calculation.
485 */
486 unsigned long nr_running;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200487 #define CPU_LOAD_IDX_MAX 5
488 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
Siddha, Suresh Bbdecea32007-05-08 00:32:48 -0700489 unsigned char idle_at_tick;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -0700490#ifdef CONFIG_NO_HZ
Guillaume Chazarain15934a32008-04-19 19:44:57 +0200491 unsigned long last_tick_seen;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -0700492 unsigned char in_nohz_recently;
493#endif
Ingo Molnard8016492007-10-18 21:32:55 +0200494 /* capture load from *all* tasks on this cpu: */
495 struct load_weight load;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200496 unsigned long nr_load_updates;
497 u64 nr_switches;
498
499 struct cfs_rq cfs;
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100500 struct rt_rq rt;
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100501
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200502#ifdef CONFIG_FAIR_GROUP_SCHED
Ingo Molnard8016492007-10-18 21:32:55 +0200503 /* list of leaf cfs_rq on this cpu: */
504 struct list_head leaf_cfs_rq_list;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +0100505#endif
506#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +0100507 struct list_head leaf_rt_rq_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700508#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509
510 /*
511 * This is part of a global counter where only the total sum
512 * over all CPUs matters. A task can increase this counter on
513 * one CPU and if it got migrated afterwards it may decrease
514 * it on another CPU. Always updated under the runqueue lock:
515 */
516 unsigned long nr_uninterruptible;
517
Ingo Molnar36c8b582006-07-03 00:25:41 -0700518 struct task_struct *curr, *idle;
Christoph Lameterc9819f42006-12-10 02:20:25 -0800519 unsigned long next_balance;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520 struct mm_struct *prev_mm;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200521
Peter Zijlstra3e51f332008-05-03 18:29:28 +0200522 u64 clock;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200523
Linus Torvalds1da177e2005-04-16 15:20:36 -0700524 atomic_t nr_iowait;
525
526#ifdef CONFIG_SMP
Ingo Molnar0eab9142008-01-25 21:08:19 +0100527 struct root_domain *rd;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700528 struct sched_domain *sd;
529
530 /* For active balancing */
531 int active_balance;
532 int push_cpu;
Ingo Molnard8016492007-10-18 21:32:55 +0200533 /* cpu of this runqueue: */
534 int cpu;
Gregory Haskins1f11eb62008-06-04 15:04:05 -0400535 int online;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700536
Ingo Molnar36c8b582006-07-03 00:25:41 -0700537 struct task_struct *migration_thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700538 struct list_head migration_queue;
539#endif
540
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +0100541#ifdef CONFIG_SCHED_HRTICK
542 unsigned long hrtick_flags;
543 ktime_t hrtick_expire;
544 struct hrtimer hrtick_timer;
545#endif
546
Linus Torvalds1da177e2005-04-16 15:20:36 -0700547#ifdef CONFIG_SCHEDSTATS
548 /* latency stats */
549 struct sched_info rq_sched_info;
550
551 /* sys_sched_yield() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200552 unsigned int yld_exp_empty;
553 unsigned int yld_act_empty;
554 unsigned int yld_both_empty;
555 unsigned int yld_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700556
557 /* schedule() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200558 unsigned int sched_switch;
559 unsigned int sched_count;
560 unsigned int sched_goidle;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562 /* try_to_wake_up() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200563 unsigned int ttwu_count;
564 unsigned int ttwu_local;
Ingo Molnarb8efb562007-10-15 17:00:10 +0200565
566 /* BKL stats */
Ken Chen480b9432007-10-18 21:32:56 +0200567 unsigned int bkl_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700568#endif
Ingo Molnarfcb99372006-07-03 00:25:10 -0700569 struct lock_class_key rq_lock_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700570};
571
Fenghua Yuf34e3b62007-07-19 01:48:13 -0700572static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700573
Ingo Molnardd41f592007-07-09 18:51:59 +0200574static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
575{
576 rq->curr->sched_class->check_preempt_curr(rq, p);
577}
578
Christoph Lameter0a2966b2006-09-25 23:30:51 -0700579static inline int cpu_of(struct rq *rq)
580{
581#ifdef CONFIG_SMP
582 return rq->cpu;
583#else
584 return 0;
585#endif
586}
587
Ingo Molnar20d315d2007-07-09 18:51:58 +0200588/*
Nick Piggin674311d2005-06-25 14:57:27 -0700589 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -0700590 * See detach_destroy_domains: synchronize_sched for details.
Nick Piggin674311d2005-06-25 14:57:27 -0700591 *
592 * The domain tree of any CPU may only be accessed from within
593 * preempt-disabled sections.
594 */
Ingo Molnar48f24c42006-07-03 00:25:40 -0700595#define for_each_domain(cpu, __sd) \
596 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700597
598#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
599#define this_rq() (&__get_cpu_var(runqueues))
600#define task_rq(p) cpu_rq(task_cpu(p))
601#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
602
Peter Zijlstra3e51f332008-05-03 18:29:28 +0200603static inline void update_rq_clock(struct rq *rq)
604{
605 rq->clock = sched_clock_cpu(cpu_of(rq));
606}
607
Ingo Molnare436d802007-07-19 21:28:35 +0200608/*
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200609 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
610 */
611#ifdef CONFIG_SCHED_DEBUG
612# define const_debug __read_mostly
613#else
614# define const_debug static const
615#endif
616
617/*
618 * Debugging: various feature bits
619 */
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200620
621#define SCHED_FEAT(name, enabled) \
622 __SCHED_FEAT_##name ,
623
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200624enum {
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200625#include "sched_features.h"
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200626};
627
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200628#undef SCHED_FEAT
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200629
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200630#define SCHED_FEAT(name, enabled) \
631 (1UL << __SCHED_FEAT_##name) * enabled |
632
633const_debug unsigned int sysctl_sched_features =
634#include "sched_features.h"
635 0;
636
637#undef SCHED_FEAT
638
639#ifdef CONFIG_SCHED_DEBUG
640#define SCHED_FEAT(name, enabled) \
641 #name ,
642
Harvey Harrison983ed7a2008-04-24 18:17:55 -0700643static __read_mostly char *sched_feat_names[] = {
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200644#include "sched_features.h"
645 NULL
646};
647
648#undef SCHED_FEAT
649
Harvey Harrison983ed7a2008-04-24 18:17:55 -0700650static int sched_feat_open(struct inode *inode, struct file *filp)
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200651{
652 filp->private_data = inode->i_private;
653 return 0;
654}
655
656static ssize_t
657sched_feat_read(struct file *filp, char __user *ubuf,
658 size_t cnt, loff_t *ppos)
659{
660 char *buf;
661 int r = 0;
662 int len = 0;
663 int i;
664
665 for (i = 0; sched_feat_names[i]; i++) {
666 len += strlen(sched_feat_names[i]);
667 len += 4;
668 }
669
670 buf = kmalloc(len + 2, GFP_KERNEL);
671 if (!buf)
672 return -ENOMEM;
673
674 for (i = 0; sched_feat_names[i]; i++) {
675 if (sysctl_sched_features & (1UL << i))
676 r += sprintf(buf + r, "%s ", sched_feat_names[i]);
677 else
Ingo Molnarc24b7c52008-04-18 10:55:34 +0200678 r += sprintf(buf + r, "NO_%s ", sched_feat_names[i]);
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200679 }
680
681 r += sprintf(buf + r, "\n");
682 WARN_ON(r >= len + 2);
683
684 r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r);
685
686 kfree(buf);
687
688 return r;
689}
690
691static ssize_t
692sched_feat_write(struct file *filp, const char __user *ubuf,
693 size_t cnt, loff_t *ppos)
694{
695 char buf[64];
696 char *cmp = buf;
697 int neg = 0;
698 int i;
699
700 if (cnt > 63)
701 cnt = 63;
702
703 if (copy_from_user(&buf, ubuf, cnt))
704 return -EFAULT;
705
706 buf[cnt] = 0;
707
Ingo Molnarc24b7c52008-04-18 10:55:34 +0200708 if (strncmp(buf, "NO_", 3) == 0) {
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200709 neg = 1;
710 cmp += 3;
711 }
712
713 for (i = 0; sched_feat_names[i]; i++) {
714 int len = strlen(sched_feat_names[i]);
715
716 if (strncmp(cmp, sched_feat_names[i], len) == 0) {
717 if (neg)
718 sysctl_sched_features &= ~(1UL << i);
719 else
720 sysctl_sched_features |= (1UL << i);
721 break;
722 }
723 }
724
725 if (!sched_feat_names[i])
726 return -EINVAL;
727
728 filp->f_pos += cnt;
729
730 return cnt;
731}
732
733static struct file_operations sched_feat_fops = {
734 .open = sched_feat_open,
735 .read = sched_feat_read,
736 .write = sched_feat_write,
737};
738
739static __init int sched_init_debug(void)
740{
Peter Zijlstraf00b45c2008-04-19 19:45:00 +0200741 debugfs_create_file("sched_features", 0644, NULL, NULL,
742 &sched_feat_fops);
743
744 return 0;
745}
746late_initcall(sched_init_debug);
747
748#endif
749
750#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200751
752/*
Peter Zijlstrab82d9fd2007-11-09 22:39:39 +0100753 * Number of tasks to iterate in a single balance run.
754 * Limited because this is done with IRQs disabled.
755 */
756const_debug unsigned int sysctl_sched_nr_migrate = 32;
757
758/*
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +0100759 * period over which we measure -rt task cpu usage in us.
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100760 * default: 1s
761 */
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +0100762unsigned int sysctl_sched_rt_period = 1000000;
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100763
Ingo Molnar6892b752008-02-13 14:02:36 +0100764static __read_mostly int scheduler_running;
765
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100766/*
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +0100767 * part of the period that we allow rt tasks to run in us.
768 * default: 0.95s
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100769 */
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +0100770int sysctl_sched_rt_runtime = 950000;
771
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +0200772static inline u64 global_rt_period(void)
773{
774 return (u64)sysctl_sched_rt_period * NSEC_PER_USEC;
775}
776
777static inline u64 global_rt_runtime(void)
778{
779 if (sysctl_sched_rt_period < 0)
780 return RUNTIME_INF;
781
782 return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC;
783}
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100784
Ingo Molnar690229a2008-04-23 09:31:35 +0200785unsigned long long time_sync_thresh = 100000;
Ingo Molnar27ec4402008-02-28 21:00:21 +0100786
787static DEFINE_PER_CPU(unsigned long long, time_offset);
788static DEFINE_PER_CPU(unsigned long long, prev_cpu_time);
789
Peter Zijlstrafa85ae22008-01-25 21:08:29 +0100790/*
Ingo Molnar27ec4402008-02-28 21:00:21 +0100791 * Global lock which we take every now and then to synchronize
792 * the CPUs time. This method is not warp-safe, but it's good
793 * enough to synchronize slowly diverging time sources and thus
794 * it's good enough for tracing:
Ingo Molnare436d802007-07-19 21:28:35 +0200795 */
Ingo Molnar27ec4402008-02-28 21:00:21 +0100796static DEFINE_SPINLOCK(time_sync_lock);
797static unsigned long long prev_global_time;
798
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200799static unsigned long long __sync_cpu_clock(unsigned long long time, int cpu)
Ingo Molnar27ec4402008-02-28 21:00:21 +0100800{
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200801 /*
802 * We want this inlined, to not get tracer function calls
803 * in this critical section:
804 */
805 spin_acquire(&time_sync_lock.dep_map, 0, 0, _THIS_IP_);
806 __raw_spin_lock(&time_sync_lock.raw_lock);
Ingo Molnar27ec4402008-02-28 21:00:21 +0100807
808 if (time < prev_global_time) {
809 per_cpu(time_offset, cpu) += prev_global_time - time;
810 time = prev_global_time;
811 } else {
812 prev_global_time = time;
813 }
814
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200815 __raw_spin_unlock(&time_sync_lock.raw_lock);
816 spin_release(&time_sync_lock.dep_map, 1, _THIS_IP_);
Ingo Molnar27ec4402008-02-28 21:00:21 +0100817
818 return time;
819}
820
821static unsigned long long __cpu_clock(int cpu)
Ingo Molnare436d802007-07-19 21:28:35 +0200822{
Ingo Molnare436d802007-07-19 21:28:35 +0200823 unsigned long long now;
Ingo Molnare436d802007-07-19 21:28:35 +0200824
Ingo Molnar8ced5f62007-12-07 19:02:47 +0100825 /*
826 * Only call sched_clock() if the scheduler has already been
827 * initialized (some code might call cpu_clock() very early):
828 */
Ingo Molnar6892b752008-02-13 14:02:36 +0100829 if (unlikely(!scheduler_running))
830 return 0;
831
Peter Zijlstra3e51f332008-05-03 18:29:28 +0200832 now = sched_clock_cpu(cpu);
Ingo Molnare436d802007-07-19 21:28:35 +0200833
834 return now;
835}
Ingo Molnar27ec4402008-02-28 21:00:21 +0100836
837/*
838 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
839 * clock constructed from sched_clock():
840 */
841unsigned long long cpu_clock(int cpu)
842{
843 unsigned long long prev_cpu_time, time, delta_time;
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200844 unsigned long flags;
Ingo Molnar27ec4402008-02-28 21:00:21 +0100845
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200846 local_irq_save(flags);
Ingo Molnar27ec4402008-02-28 21:00:21 +0100847 prev_cpu_time = per_cpu(prev_cpu_time, cpu);
848 time = __cpu_clock(cpu) + per_cpu(time_offset, cpu);
849 delta_time = time-prev_cpu_time;
850
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200851 if (unlikely(delta_time > time_sync_thresh)) {
Ingo Molnar27ec4402008-02-28 21:00:21 +0100852 time = __sync_cpu_clock(time, cpu);
Ingo Molnardfbf4a12008-04-23 09:24:06 +0200853 per_cpu(prev_cpu_time, cpu) = time;
854 }
855 local_irq_restore(flags);
Ingo Molnar27ec4402008-02-28 21:00:21 +0100856
857 return time;
858}
Paul E. McKenneya58f6f22007-10-15 17:00:14 +0200859EXPORT_SYMBOL_GPL(cpu_clock);
Ingo Molnare436d802007-07-19 21:28:35 +0200860
Linus Torvalds1da177e2005-04-16 15:20:36 -0700861#ifndef prepare_arch_switch
Nick Piggin4866cde2005-06-25 14:57:23 -0700862# define prepare_arch_switch(next) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700863#endif
Nick Piggin4866cde2005-06-25 14:57:23 -0700864#ifndef finish_arch_switch
865# define finish_arch_switch(prev) do { } while (0)
866#endif
867
Dmitry Adamushko051a1d12007-12-18 15:21:13 +0100868static inline int task_current(struct rq *rq, struct task_struct *p)
869{
870 return rq->curr == p;
871}
872
Nick Piggin4866cde2005-06-25 14:57:23 -0700873#ifndef __ARCH_WANT_UNLOCKED_CTXSW
Ingo Molnar70b97a72006-07-03 00:25:42 -0700874static inline int task_running(struct rq *rq, struct task_struct *p)
Nick Piggin4866cde2005-06-25 14:57:23 -0700875{
Dmitry Adamushko051a1d12007-12-18 15:21:13 +0100876 return task_current(rq, p);
Nick Piggin4866cde2005-06-25 14:57:23 -0700877}
878
Ingo Molnar70b97a72006-07-03 00:25:42 -0700879static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -0700880{
881}
882
Ingo Molnar70b97a72006-07-03 00:25:42 -0700883static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
Nick Piggin4866cde2005-06-25 14:57:23 -0700884{
Ingo Molnarda04c032005-09-13 11:17:59 +0200885#ifdef CONFIG_DEBUG_SPINLOCK
886 /* this is a valid case when another task releases the spinlock */
887 rq->lock.owner = current;
888#endif
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700889 /*
890 * If we are tracking spinlock dependencies then we have to
891 * fix up the runqueue lock - which gets 'carried over' from
892 * prev into current:
893 */
894 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
895
Nick Piggin4866cde2005-06-25 14:57:23 -0700896 spin_unlock_irq(&rq->lock);
897}
898
899#else /* __ARCH_WANT_UNLOCKED_CTXSW */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700900static inline int task_running(struct rq *rq, struct task_struct *p)
Nick Piggin4866cde2005-06-25 14:57:23 -0700901{
902#ifdef CONFIG_SMP
903 return p->oncpu;
904#else
Dmitry Adamushko051a1d12007-12-18 15:21:13 +0100905 return task_current(rq, p);
Nick Piggin4866cde2005-06-25 14:57:23 -0700906#endif
907}
908
Ingo Molnar70b97a72006-07-03 00:25:42 -0700909static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -0700910{
911#ifdef CONFIG_SMP
912 /*
913 * We can optimise this out completely for !SMP, because the
914 * SMP rebalancing from interrupt is the only thing that cares
915 * here.
916 */
917 next->oncpu = 1;
918#endif
919#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
920 spin_unlock_irq(&rq->lock);
921#else
922 spin_unlock(&rq->lock);
923#endif
924}
925
Ingo Molnar70b97a72006-07-03 00:25:42 -0700926static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
Nick Piggin4866cde2005-06-25 14:57:23 -0700927{
928#ifdef CONFIG_SMP
929 /*
930 * After ->oncpu is cleared, the task can be moved to a different CPU.
931 * We must ensure this doesn't happen until the switch is completely
932 * finished.
933 */
934 smp_wmb();
935 prev->oncpu = 0;
936#endif
937#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
938 local_irq_enable();
939#endif
940}
941#endif /* __ARCH_WANT_UNLOCKED_CTXSW */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700942
943/*
Ingo Molnarb29739f2006-06-27 02:54:51 -0700944 * __task_rq_lock - lock the runqueue a given task resides on.
945 * Must be called interrupts disabled.
946 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700947static inline struct rq *__task_rq_lock(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700948 __acquires(rq->lock)
949{
Andi Kleen3a5c3592007-10-15 17:00:14 +0200950 for (;;) {
951 struct rq *rq = task_rq(p);
952 spin_lock(&rq->lock);
953 if (likely(rq == task_rq(p)))
954 return rq;
Ingo Molnarb29739f2006-06-27 02:54:51 -0700955 spin_unlock(&rq->lock);
Ingo Molnarb29739f2006-06-27 02:54:51 -0700956 }
Ingo Molnarb29739f2006-06-27 02:54:51 -0700957}
958
959/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700960 * task_rq_lock - lock the runqueue a given task resides on and disable
Ingo Molnar41a2d6c2007-12-05 15:46:09 +0100961 * interrupts. Note the ordering: we can safely lookup the task_rq without
Linus Torvalds1da177e2005-04-16 15:20:36 -0700962 * explicitly disabling preemption.
963 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700964static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 __acquires(rq->lock)
966{
Ingo Molnar70b97a72006-07-03 00:25:42 -0700967 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700968
Andi Kleen3a5c3592007-10-15 17:00:14 +0200969 for (;;) {
970 local_irq_save(*flags);
971 rq = task_rq(p);
972 spin_lock(&rq->lock);
973 if (likely(rq == task_rq(p)))
974 return rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700975 spin_unlock_irqrestore(&rq->lock, *flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700977}
978
Alexey Dobriyana9957442007-10-15 17:00:13 +0200979static void __task_rq_unlock(struct rq *rq)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700980 __releases(rq->lock)
981{
982 spin_unlock(&rq->lock);
983}
984
Ingo Molnar70b97a72006-07-03 00:25:42 -0700985static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 __releases(rq->lock)
987{
988 spin_unlock_irqrestore(&rq->lock, *flags);
989}
990
Linus Torvalds1da177e2005-04-16 15:20:36 -0700991/*
Robert P. J. Daycc2a73b2006-12-10 02:20:00 -0800992 * this_rq_lock - lock this runqueue and disable interrupts.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700993 */
Alexey Dobriyana9957442007-10-15 17:00:13 +0200994static struct rq *this_rq_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700995 __acquires(rq->lock)
996{
Ingo Molnar70b97a72006-07-03 00:25:42 -0700997 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700998
999 local_irq_disable();
1000 rq = this_rq();
1001 spin_lock(&rq->lock);
1002
1003 return rq;
1004}
1005
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001006static void __resched_task(struct task_struct *p, int tif_bit);
1007
1008static inline void resched_task(struct task_struct *p)
1009{
1010 __resched_task(p, TIF_NEED_RESCHED);
1011}
1012
1013#ifdef CONFIG_SCHED_HRTICK
1014/*
1015 * Use HR-timers to deliver accurate preemption points.
1016 *
1017 * Its all a bit involved since we cannot program an hrt while holding the
1018 * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a
1019 * reschedule event.
1020 *
1021 * When we get rescheduled we reprogram the hrtick_timer outside of the
1022 * rq->lock.
1023 */
1024static inline void resched_hrt(struct task_struct *p)
1025{
1026 __resched_task(p, TIF_HRTICK_RESCHED);
1027}
1028
1029static inline void resched_rq(struct rq *rq)
1030{
1031 unsigned long flags;
1032
1033 spin_lock_irqsave(&rq->lock, flags);
1034 resched_task(rq->curr);
1035 spin_unlock_irqrestore(&rq->lock, flags);
1036}
1037
1038enum {
1039 HRTICK_SET, /* re-programm hrtick_timer */
1040 HRTICK_RESET, /* not a new slice */
Peter Zijlstrab328ca12008-04-29 10:02:46 +02001041 HRTICK_BLOCK, /* stop hrtick operations */
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001042};
1043
1044/*
1045 * Use hrtick when:
1046 * - enabled by features
1047 * - hrtimer is actually high res
1048 */
1049static inline int hrtick_enabled(struct rq *rq)
1050{
1051 if (!sched_feat(HRTICK))
1052 return 0;
Peter Zijlstrab328ca12008-04-29 10:02:46 +02001053 if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags)))
1054 return 0;
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001055 return hrtimer_is_hres_active(&rq->hrtick_timer);
1056}
1057
1058/*
1059 * Called to set the hrtick timer state.
1060 *
1061 * called with rq->lock held and irqs disabled
1062 */
1063static void hrtick_start(struct rq *rq, u64 delay, int reset)
1064{
1065 assert_spin_locked(&rq->lock);
1066
1067 /*
1068 * preempt at: now + delay
1069 */
1070 rq->hrtick_expire =
1071 ktime_add_ns(rq->hrtick_timer.base->get_time(), delay);
1072 /*
1073 * indicate we need to program the timer
1074 */
1075 __set_bit(HRTICK_SET, &rq->hrtick_flags);
1076 if (reset)
1077 __set_bit(HRTICK_RESET, &rq->hrtick_flags);
1078
1079 /*
1080 * New slices are called from the schedule path and don't need a
1081 * forced reschedule.
1082 */
1083 if (reset)
1084 resched_hrt(rq->curr);
1085}
1086
1087static void hrtick_clear(struct rq *rq)
1088{
1089 if (hrtimer_active(&rq->hrtick_timer))
1090 hrtimer_cancel(&rq->hrtick_timer);
1091}
1092
1093/*
1094 * Update the timer from the possible pending state.
1095 */
1096static void hrtick_set(struct rq *rq)
1097{
1098 ktime_t time;
1099 int set, reset;
1100 unsigned long flags;
1101
1102 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1103
1104 spin_lock_irqsave(&rq->lock, flags);
1105 set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags);
1106 reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags);
1107 time = rq->hrtick_expire;
1108 clear_thread_flag(TIF_HRTICK_RESCHED);
1109 spin_unlock_irqrestore(&rq->lock, flags);
1110
1111 if (set) {
1112 hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS);
1113 if (reset && !hrtimer_active(&rq->hrtick_timer))
1114 resched_rq(rq);
1115 } else
1116 hrtick_clear(rq);
1117}
1118
1119/*
1120 * High-resolution timer tick.
1121 * Runs from hardirq context with interrupts disabled.
1122 */
1123static enum hrtimer_restart hrtick(struct hrtimer *timer)
1124{
1125 struct rq *rq = container_of(timer, struct rq, hrtick_timer);
1126
1127 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
1128
1129 spin_lock(&rq->lock);
Peter Zijlstra3e51f332008-05-03 18:29:28 +02001130 update_rq_clock(rq);
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001131 rq->curr->sched_class->task_tick(rq, rq->curr, 1);
1132 spin_unlock(&rq->lock);
1133
1134 return HRTIMER_NORESTART;
1135}
1136
Rabin Vincent81d41d72008-05-11 05:55:33 +05301137#ifdef CONFIG_SMP
Peter Zijlstrab328ca12008-04-29 10:02:46 +02001138static void hotplug_hrtick_disable(int cpu)
1139{
1140 struct rq *rq = cpu_rq(cpu);
1141 unsigned long flags;
1142
1143 spin_lock_irqsave(&rq->lock, flags);
1144 rq->hrtick_flags = 0;
1145 __set_bit(HRTICK_BLOCK, &rq->hrtick_flags);
1146 spin_unlock_irqrestore(&rq->lock, flags);
1147
1148 hrtick_clear(rq);
1149}
1150
1151static void hotplug_hrtick_enable(int cpu)
1152{
1153 struct rq *rq = cpu_rq(cpu);
1154 unsigned long flags;
1155
1156 spin_lock_irqsave(&rq->lock, flags);
1157 __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags);
1158 spin_unlock_irqrestore(&rq->lock, flags);
1159}
1160
1161static int
1162hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu)
1163{
1164 int cpu = (int)(long)hcpu;
1165
1166 switch (action) {
1167 case CPU_UP_CANCELED:
1168 case CPU_UP_CANCELED_FROZEN:
1169 case CPU_DOWN_PREPARE:
1170 case CPU_DOWN_PREPARE_FROZEN:
1171 case CPU_DEAD:
1172 case CPU_DEAD_FROZEN:
1173 hotplug_hrtick_disable(cpu);
1174 return NOTIFY_OK;
1175
1176 case CPU_UP_PREPARE:
1177 case CPU_UP_PREPARE_FROZEN:
1178 case CPU_DOWN_FAILED:
1179 case CPU_DOWN_FAILED_FROZEN:
1180 case CPU_ONLINE:
1181 case CPU_ONLINE_FROZEN:
1182 hotplug_hrtick_enable(cpu);
1183 return NOTIFY_OK;
1184 }
1185
1186 return NOTIFY_DONE;
1187}
1188
1189static void init_hrtick(void)
1190{
1191 hotcpu_notifier(hotplug_hrtick, 0);
1192}
Rabin Vincent81d41d72008-05-11 05:55:33 +05301193#endif /* CONFIG_SMP */
Peter Zijlstrab328ca12008-04-29 10:02:46 +02001194
1195static void init_rq_hrtick(struct rq *rq)
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001196{
1197 rq->hrtick_flags = 0;
1198 hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
1199 rq->hrtick_timer.function = hrtick;
1200 rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ;
1201}
1202
1203void hrtick_resched(void)
1204{
1205 struct rq *rq;
1206 unsigned long flags;
1207
1208 if (!test_thread_flag(TIF_HRTICK_RESCHED))
1209 return;
1210
1211 local_irq_save(flags);
1212 rq = cpu_rq(smp_processor_id());
1213 hrtick_set(rq);
1214 local_irq_restore(flags);
1215}
1216#else
1217static inline void hrtick_clear(struct rq *rq)
1218{
1219}
1220
1221static inline void hrtick_set(struct rq *rq)
1222{
1223}
1224
1225static inline void init_rq_hrtick(struct rq *rq)
1226{
1227}
1228
1229void hrtick_resched(void)
1230{
1231}
Peter Zijlstrab328ca12008-04-29 10:02:46 +02001232
1233static inline void init_hrtick(void)
1234{
1235}
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001236#endif
1237
Ingo Molnar1b9f19c2007-07-09 18:51:59 +02001238/*
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001239 * resched_task - mark a task 'to be rescheduled now'.
1240 *
1241 * On UP this means the setting of the need_resched flag, on SMP it
1242 * might also involve a cross-CPU call to trigger the scheduler on
1243 * the target CPU.
1244 */
1245#ifdef CONFIG_SMP
1246
1247#ifndef tsk_is_polling
1248#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
1249#endif
1250
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001251static void __resched_task(struct task_struct *p, int tif_bit)
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001252{
1253 int cpu;
1254
1255 assert_spin_locked(&task_rq(p)->lock);
1256
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001257 if (unlikely(test_tsk_thread_flag(p, tif_bit)))
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001258 return;
1259
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001260 set_tsk_thread_flag(p, tif_bit);
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001261
1262 cpu = task_cpu(p);
1263 if (cpu == smp_processor_id())
1264 return;
1265
1266 /* NEED_RESCHED must be visible before we test polling */
1267 smp_mb();
1268 if (!tsk_is_polling(p))
1269 smp_send_reschedule(cpu);
1270}
1271
1272static void resched_cpu(int cpu)
1273{
1274 struct rq *rq = cpu_rq(cpu);
1275 unsigned long flags;
1276
1277 if (!spin_trylock_irqsave(&rq->lock, flags))
1278 return;
1279 resched_task(cpu_curr(cpu));
1280 spin_unlock_irqrestore(&rq->lock, flags);
1281}
Thomas Gleixner06d83082008-03-22 09:20:24 +01001282
1283#ifdef CONFIG_NO_HZ
1284/*
1285 * When add_timer_on() enqueues a timer into the timer wheel of an
1286 * idle CPU then this timer might expire before the next timer event
1287 * which is scheduled to wake up that CPU. In case of a completely
1288 * idle system the next event might even be infinite time into the
1289 * future. wake_up_idle_cpu() ensures that the CPU is woken up and
1290 * leaves the inner idle loop so the newly added timer is taken into
1291 * account when the CPU goes back to idle and evaluates the timer
1292 * wheel for the next timer event.
1293 */
1294void wake_up_idle_cpu(int cpu)
1295{
1296 struct rq *rq = cpu_rq(cpu);
1297
1298 if (cpu == smp_processor_id())
1299 return;
1300
1301 /*
1302 * This is safe, as this function is called with the timer
1303 * wheel base lock of (cpu) held. When the CPU is on the way
1304 * to idle and has not yet set rq->curr to idle then it will
1305 * be serialized on the timer wheel base lock and take the new
1306 * timer into account automatically.
1307 */
1308 if (rq->curr != rq->idle)
1309 return;
1310
1311 /*
1312 * We can set TIF_RESCHED on the idle task of the other CPU
1313 * lockless. The worst case is that the other CPU runs the
1314 * idle task through an additional NOOP schedule()
1315 */
1316 set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
1317
1318 /* NEED_RESCHED must be visible before we test polling */
1319 smp_mb();
1320 if (!tsk_is_polling(rq->idle))
1321 smp_send_reschedule(cpu);
1322}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02001323#endif /* CONFIG_NO_HZ */
Thomas Gleixner06d83082008-03-22 09:20:24 +01001324
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02001325#else /* !CONFIG_SMP */
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001326static void __resched_task(struct task_struct *p, int tif_bit)
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001327{
1328 assert_spin_locked(&task_rq(p)->lock);
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01001329 set_tsk_thread_flag(p, tif_bit);
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001330}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02001331#endif /* CONFIG_SMP */
Ingo Molnarc24d20d2007-07-09 18:51:59 +02001332
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001333#if BITS_PER_LONG == 32
1334# define WMULT_CONST (~0UL)
1335#else
1336# define WMULT_CONST (1UL << 32)
1337#endif
1338
1339#define WMULT_SHIFT 32
1340
Ingo Molnar194081e2007-08-09 11:16:51 +02001341/*
1342 * Shift right and round:
1343 */
Ingo Molnarcf2ab462007-09-05 14:32:49 +02001344#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
Ingo Molnar194081e2007-08-09 11:16:51 +02001345
Ingo Molnarcb1c4fc2007-08-02 17:41:40 +02001346static unsigned long
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001347calc_delta_mine(unsigned long delta_exec, unsigned long weight,
1348 struct load_weight *lw)
1349{
1350 u64 tmp;
1351
Lai Jiangshan7a232e02008-06-12 16:43:07 +08001352 if (!lw->inv_weight) {
1353 if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST))
1354 lw->inv_weight = 1;
1355 else
1356 lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2)
1357 / (lw->weight+1);
1358 }
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001359
1360 tmp = (u64)delta_exec * weight;
1361 /*
1362 * Check whether we'd overflow the 64-bit multiplication:
1363 */
Ingo Molnar194081e2007-08-09 11:16:51 +02001364 if (unlikely(tmp > WMULT_CONST))
Ingo Molnarcf2ab462007-09-05 14:32:49 +02001365 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
Ingo Molnar194081e2007-08-09 11:16:51 +02001366 WMULT_SHIFT/2);
1367 else
Ingo Molnarcf2ab462007-09-05 14:32:49 +02001368 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001369
Ingo Molnarecf691d2007-08-02 17:41:40 +02001370 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001371}
1372
Ingo Molnarf9305d42008-05-29 11:23:17 +02001373static inline unsigned long
1374calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
1375{
1376 return calc_delta_mine(delta_exec, NICE_0_LOAD, lw);
1377}
1378
Ingo Molnar10919852007-10-15 17:00:04 +02001379static inline void update_load_add(struct load_weight *lw, unsigned long inc)
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001380{
1381 lw->weight += inc;
Ingo Molnare89996a2008-03-14 23:48:28 +01001382 lw->inv_weight = 0;
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001383}
1384
Ingo Molnar10919852007-10-15 17:00:04 +02001385static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001386{
1387 lw->weight -= dec;
Ingo Molnare89996a2008-03-14 23:48:28 +01001388 lw->inv_weight = 0;
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001389}
1390
Linus Torvalds1da177e2005-04-16 15:20:36 -07001391/*
Peter Williams2dd73a42006-06-27 02:54:34 -07001392 * To aid in avoiding the subversion of "niceness" due to uneven distribution
1393 * of tasks with abnormal "nice" values across CPUs the contribution that
1394 * each task makes to its run queue's load is weighted according to its
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01001395 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
Peter Williams2dd73a42006-06-27 02:54:34 -07001396 * scaled version of the new time slice allocation that they receive on time
1397 * slice expiry etc.
1398 */
1399
Ingo Molnardd41f592007-07-09 18:51:59 +02001400#define WEIGHT_IDLEPRIO 2
1401#define WMULT_IDLEPRIO (1 << 31)
1402
1403/*
1404 * Nice levels are multiplicative, with a gentle 10% change for every
1405 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
1406 * nice 1, it will get ~10% less CPU time than another CPU-bound task
1407 * that remained on nice 0.
1408 *
1409 * The "10% effect" is relative and cumulative: from _any_ nice level,
1410 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
Ingo Molnarf9153ee2007-07-16 09:46:30 +02001411 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
1412 * If a task goes up by ~10% and another task goes down by ~10% then
1413 * the relative distance between them is ~25%.)
Ingo Molnardd41f592007-07-09 18:51:59 +02001414 */
1415static const int prio_to_weight[40] = {
Ingo Molnar254753d2007-08-09 11:16:51 +02001416 /* -20 */ 88761, 71755, 56483, 46273, 36291,
1417 /* -15 */ 29154, 23254, 18705, 14949, 11916,
1418 /* -10 */ 9548, 7620, 6100, 4904, 3906,
1419 /* -5 */ 3121, 2501, 1991, 1586, 1277,
1420 /* 0 */ 1024, 820, 655, 526, 423,
1421 /* 5 */ 335, 272, 215, 172, 137,
1422 /* 10 */ 110, 87, 70, 56, 45,
1423 /* 15 */ 36, 29, 23, 18, 15,
Ingo Molnardd41f592007-07-09 18:51:59 +02001424};
1425
Ingo Molnar5714d2d2007-07-16 09:46:31 +02001426/*
1427 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
1428 *
1429 * In cases where the weight does not change often, we can use the
1430 * precalculated inverse to speed up arithmetics by turning divisions
1431 * into multiplications:
1432 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001433static const u32 prio_to_wmult[40] = {
Ingo Molnar254753d2007-08-09 11:16:51 +02001434 /* -20 */ 48388, 59856, 76040, 92818, 118348,
1435 /* -15 */ 147320, 184698, 229616, 287308, 360437,
1436 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
1437 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
1438 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
1439 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
1440 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
1441 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
Ingo Molnardd41f592007-07-09 18:51:59 +02001442};
Peter Williams2dd73a42006-06-27 02:54:34 -07001443
Ingo Molnardd41f592007-07-09 18:51:59 +02001444static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
1445
1446/*
1447 * runqueue iterator, to support SMP load-balancing between different
1448 * scheduling classes, without having to expose their internal data
1449 * structures to the load-balancing proper:
1450 */
1451struct rq_iterator {
1452 void *arg;
1453 struct task_struct *(*start)(void *);
1454 struct task_struct *(*next)(void *);
1455};
1456
Peter Williamse1d14842007-10-24 18:23:51 +02001457#ifdef CONFIG_SMP
1458static unsigned long
1459balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
1460 unsigned long max_load_move, struct sched_domain *sd,
1461 enum cpu_idle_type idle, int *all_pinned,
1462 int *this_best_prio, struct rq_iterator *iterator);
1463
1464static int
1465iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
1466 struct sched_domain *sd, enum cpu_idle_type idle,
1467 struct rq_iterator *iterator);
Peter Williamse1d14842007-10-24 18:23:51 +02001468#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02001469
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01001470#ifdef CONFIG_CGROUP_CPUACCT
1471static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
1472#else
1473static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
1474#endif
1475
Peter Zijlstra18d95a22008-04-19 19:45:00 +02001476static inline void inc_cpu_load(struct rq *rq, unsigned long load)
1477{
1478 update_load_add(&rq->load, load);
1479}
1480
1481static inline void dec_cpu_load(struct rq *rq, unsigned long load)
1482{
1483 update_load_sub(&rq->load, load);
1484}
1485
Gregory Haskinse7693a32008-01-25 21:08:09 +01001486#ifdef CONFIG_SMP
1487static unsigned long source_load(int cpu, int type);
1488static unsigned long target_load(int cpu, int type);
1489static unsigned long cpu_avg_load_per_task(int cpu);
1490static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd);
Peter Zijlstra18d95a22008-04-19 19:45:00 +02001491#endif
1492
Ingo Molnardd41f592007-07-09 18:51:59 +02001493#include "sched_stats.h"
Ingo Molnardd41f592007-07-09 18:51:59 +02001494#include "sched_idletask.c"
Ingo Molnar5522d5d2007-10-15 17:00:12 +02001495#include "sched_fair.c"
1496#include "sched_rt.c"
Ingo Molnardd41f592007-07-09 18:51:59 +02001497#ifdef CONFIG_SCHED_DEBUG
1498# include "sched_debug.c"
1499#endif
1500
1501#define sched_class_highest (&rt_sched_class)
Gregory Haskins1f11eb62008-06-04 15:04:05 -04001502#define for_each_class(class) \
1503 for (class = sched_class_highest; class; class = class->next)
Ingo Molnardd41f592007-07-09 18:51:59 +02001504
Ingo Molnar6363ca52008-05-29 11:28:57 +02001505static inline void inc_load(struct rq *rq, const struct task_struct *p)
Peter Zijlstra62fb1852008-02-25 17:34:02 +01001506{
Ingo Molnar6363ca52008-05-29 11:28:57 +02001507 update_load_add(&rq->load, p->se.load.weight);
Peter Zijlstra62fb1852008-02-25 17:34:02 +01001508}
1509
Ingo Molnar6363ca52008-05-29 11:28:57 +02001510static inline void dec_load(struct rq *rq, const struct task_struct *p)
1511{
1512 update_load_sub(&rq->load, p->se.load.weight);
1513}
1514
1515static void inc_nr_running(struct task_struct *p, struct rq *rq)
1516{
1517 rq->nr_running++;
1518 inc_load(rq, p);
1519}
1520
1521static void dec_nr_running(struct task_struct *p, struct rq *rq)
Ingo Molnar9c217242007-08-02 17:41:40 +02001522{
1523 rq->nr_running--;
Ingo Molnar6363ca52008-05-29 11:28:57 +02001524 dec_load(rq, p);
Ingo Molnar9c217242007-08-02 17:41:40 +02001525}
1526
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001527static void set_load_weight(struct task_struct *p)
1528{
1529 if (task_has_rt_policy(p)) {
Ingo Molnardd41f592007-07-09 18:51:59 +02001530 p->se.load.weight = prio_to_weight[0] * 2;
1531 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
1532 return;
1533 }
1534
1535 /*
1536 * SCHED_IDLE tasks get minimal weight:
1537 */
1538 if (p->policy == SCHED_IDLE) {
1539 p->se.load.weight = WEIGHT_IDLEPRIO;
1540 p->se.load.inv_weight = WMULT_IDLEPRIO;
1541 return;
1542 }
1543
1544 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
1545 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
Ingo Molnar45bf76d2007-07-09 18:51:59 +02001546}
1547
Ingo Molnar8159f872007-08-09 11:16:49 +02001548static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
Ingo Molnar71f8bd42007-07-09 18:51:59 +02001549{
1550 sched_info_queued(p);
Ingo Molnarfd390f62007-08-09 11:16:48 +02001551 p->sched_class->enqueue_task(rq, p, wakeup);
Ingo Molnardd41f592007-07-09 18:51:59 +02001552 p->se.on_rq = 1;
1553}
1554
Ingo Molnar69be72c2007-08-09 11:16:49 +02001555static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
Ingo Molnardd41f592007-07-09 18:51:59 +02001556{
Ingo Molnarf02231e2007-08-09 11:16:48 +02001557 p->sched_class->dequeue_task(rq, p, sleep);
Ingo Molnardd41f592007-07-09 18:51:59 +02001558 p->se.on_rq = 0;
Ingo Molnar71f8bd42007-07-09 18:51:59 +02001559}
1560
1561/*
Ingo Molnardd41f592007-07-09 18:51:59 +02001562 * __normal_prio - return the priority that is based on the static prio
Ingo Molnar71f8bd42007-07-09 18:51:59 +02001563 */
Ingo Molnar14531182007-07-09 18:51:59 +02001564static inline int __normal_prio(struct task_struct *p)
1565{
Ingo Molnardd41f592007-07-09 18:51:59 +02001566 return p->static_prio;
Ingo Molnar14531182007-07-09 18:51:59 +02001567}
1568
1569/*
Ingo Molnarb29739f2006-06-27 02:54:51 -07001570 * Calculate the expected normal priority: i.e. priority
1571 * without taking RT-inheritance into account. Might be
1572 * boosted by interactivity modifiers. Changes upon fork,
1573 * setprio syscalls, and whenever the interactivity
1574 * estimator recalculates.
1575 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001576static inline int normal_prio(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -07001577{
1578 int prio;
1579
Ingo Molnare05606d2007-07-09 18:51:59 +02001580 if (task_has_rt_policy(p))
Ingo Molnarb29739f2006-06-27 02:54:51 -07001581 prio = MAX_RT_PRIO-1 - p->rt_priority;
1582 else
1583 prio = __normal_prio(p);
1584 return prio;
1585}
1586
1587/*
1588 * Calculate the current priority, i.e. the priority
1589 * taken into account by the scheduler. This value might
1590 * be boosted by RT tasks, or might be boosted by
1591 * interactivity modifiers. Will be RT if the task got
1592 * RT-boosted. If not then it returns p->normal_prio.
1593 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001594static int effective_prio(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -07001595{
1596 p->normal_prio = normal_prio(p);
1597 /*
1598 * If we are RT tasks or we were boosted to RT priority,
1599 * keep the priority unchanged. Otherwise, update priority
1600 * to the normal priority:
1601 */
1602 if (!rt_prio(p->prio))
1603 return p->normal_prio;
1604 return p->prio;
1605}
1606
1607/*
Ingo Molnardd41f592007-07-09 18:51:59 +02001608 * activate_task - move a task to the runqueue.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001609 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001610static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001611{
Matthew Wilcoxd9514f62007-12-06 11:07:07 -05001612 if (task_contributes_to_load(p))
Ingo Molnardd41f592007-07-09 18:51:59 +02001613 rq->nr_uninterruptible--;
1614
Ingo Molnar8159f872007-08-09 11:16:49 +02001615 enqueue_task(rq, p, wakeup);
Ingo Molnar6363ca52008-05-29 11:28:57 +02001616 inc_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001617}
1618
1619/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07001620 * deactivate_task - remove a task from the runqueue.
1621 */
Ingo Molnar2e1cb742007-08-09 11:16:49 +02001622static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001623{
Matthew Wilcoxd9514f62007-12-06 11:07:07 -05001624 if (task_contributes_to_load(p))
Ingo Molnardd41f592007-07-09 18:51:59 +02001625 rq->nr_uninterruptible++;
1626
Ingo Molnar69be72c2007-08-09 11:16:49 +02001627 dequeue_task(rq, p, sleep);
Ingo Molnar6363ca52008-05-29 11:28:57 +02001628 dec_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001629}
1630
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631/**
1632 * task_curr - is this task currently executing on a CPU?
1633 * @p: the task in question.
1634 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001635inline int task_curr(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001636{
1637 return cpu_curr(task_cpu(p)) == p;
1638}
1639
Ingo Molnardd41f592007-07-09 18:51:59 +02001640static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1641{
Peter Zijlstra6f505b12008-01-25 21:08:30 +01001642 set_task_rq(p, cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001643#ifdef CONFIG_SMP
Dmitry Adamushkoce96b5a2007-11-15 20:57:40 +01001644 /*
1645 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
1646 * successfuly executed on another CPU. We must ensure that updates of
1647 * per-task data have been completed by this moment.
1648 */
1649 smp_wmb();
Ingo Molnardd41f592007-07-09 18:51:59 +02001650 task_thread_info(p)->cpu = cpu;
Ingo Molnardd41f592007-07-09 18:51:59 +02001651#endif
Peter Williams2dd73a42006-06-27 02:54:34 -07001652}
1653
Steven Rostedtcb469842008-01-25 21:08:22 +01001654static inline void check_class_changed(struct rq *rq, struct task_struct *p,
1655 const struct sched_class *prev_class,
1656 int oldprio, int running)
1657{
1658 if (prev_class != p->sched_class) {
1659 if (prev_class->switched_from)
1660 prev_class->switched_from(rq, p, running);
1661 p->sched_class->switched_to(rq, p, running);
1662 } else
1663 p->sched_class->prio_changed(rq, p, oldprio, running);
1664}
1665
Linus Torvalds1da177e2005-04-16 15:20:36 -07001666#ifdef CONFIG_SMP
Ingo Molnarc65cc872007-07-09 18:51:58 +02001667
Thomas Gleixnere958b362008-06-04 23:22:32 +02001668/* Used instead of source_load when we know the type == 0 */
1669static unsigned long weighted_cpuload(const int cpu)
1670{
1671 return cpu_rq(cpu)->load.weight;
1672}
1673
Ingo Molnarcc367732007-10-15 17:00:18 +02001674/*
1675 * Is this task likely cache-hot:
1676 */
Gregory Haskinse7693a32008-01-25 21:08:09 +01001677static int
Ingo Molnarcc367732007-10-15 17:00:18 +02001678task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1679{
1680 s64 delta;
1681
Ingo Molnarf540a602008-03-15 17:10:34 +01001682 /*
1683 * Buddy candidates are cache hot:
1684 */
Ingo Molnard25ce4c2008-03-17 09:36:53 +01001685 if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next))
Ingo Molnarf540a602008-03-15 17:10:34 +01001686 return 1;
1687
Ingo Molnarcc367732007-10-15 17:00:18 +02001688 if (p->sched_class != &fair_sched_class)
1689 return 0;
1690
Ingo Molnar6bc16652007-10-15 17:00:18 +02001691 if (sysctl_sched_migration_cost == -1)
1692 return 1;
1693 if (sysctl_sched_migration_cost == 0)
1694 return 0;
1695
Ingo Molnarcc367732007-10-15 17:00:18 +02001696 delta = now - p->se.exec_start;
1697
1698 return delta < (s64)sysctl_sched_migration_cost;
1699}
1700
1701
Ingo Molnardd41f592007-07-09 18:51:59 +02001702void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
Ingo Molnarc65cc872007-07-09 18:51:58 +02001703{
Ingo Molnardd41f592007-07-09 18:51:59 +02001704 int old_cpu = task_cpu(p);
1705 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
Srivatsa Vaddagiri2830cf82007-10-15 17:00:12 +02001706 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1707 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
Ingo Molnarbbdba7c2007-10-15 17:00:06 +02001708 u64 clock_offset;
Ingo Molnardd41f592007-07-09 18:51:59 +02001709
1710 clock_offset = old_rq->clock - new_rq->clock;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001711
1712#ifdef CONFIG_SCHEDSTATS
1713 if (p->se.wait_start)
1714 p->se.wait_start -= clock_offset;
Ingo Molnardd41f592007-07-09 18:51:59 +02001715 if (p->se.sleep_start)
1716 p->se.sleep_start -= clock_offset;
1717 if (p->se.block_start)
1718 p->se.block_start -= clock_offset;
Ingo Molnarcc367732007-10-15 17:00:18 +02001719 if (old_cpu != new_cpu) {
1720 schedstat_inc(p, se.nr_migrations);
1721 if (task_hot(p, old_rq->clock, NULL))
1722 schedstat_inc(p, se.nr_forced2_migrations);
1723 }
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001724#endif
Srivatsa Vaddagiri2830cf82007-10-15 17:00:12 +02001725 p->se.vruntime -= old_cfsrq->min_vruntime -
1726 new_cfsrq->min_vruntime;
Ingo Molnardd41f592007-07-09 18:51:59 +02001727
1728 __set_task_cpu(p, new_cpu);
Ingo Molnarc65cc872007-07-09 18:51:58 +02001729}
1730
Ingo Molnar70b97a72006-07-03 00:25:42 -07001731struct migration_req {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001732 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733
Ingo Molnar36c8b582006-07-03 00:25:41 -07001734 struct task_struct *task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001735 int dest_cpu;
1736
Linus Torvalds1da177e2005-04-16 15:20:36 -07001737 struct completion done;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001738};
Linus Torvalds1da177e2005-04-16 15:20:36 -07001739
1740/*
1741 * The task's runqueue lock must be held.
1742 * Returns true if you have to wait for migration thread.
1743 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001744static int
Ingo Molnar70b97a72006-07-03 00:25:42 -07001745migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001746{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001747 struct rq *rq = task_rq(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001748
1749 /*
1750 * If the task is not on a runqueue (and not running), then
1751 * it is sufficient to simply update the task's cpu field.
1752 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001753 if (!p->se.on_rq && !task_running(rq, p)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001754 set_task_cpu(p, dest_cpu);
1755 return 0;
1756 }
1757
1758 init_completion(&req->done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001759 req->task = p;
1760 req->dest_cpu = dest_cpu;
1761 list_add(&req->list, &rq->migration_queue);
Ingo Molnar48f24c42006-07-03 00:25:40 -07001762
Linus Torvalds1da177e2005-04-16 15:20:36 -07001763 return 1;
1764}
1765
1766/*
1767 * wait_task_inactive - wait for a thread to unschedule.
1768 *
1769 * The caller must ensure that the task *will* unschedule sometime soon,
1770 * else this function might spin for a *long* time. This function can't
1771 * be called with interrupts off, or it may introduce deadlock with
1772 * smp_call_function() if an IPI is sent by the same process we are
1773 * waiting to become inactive.
1774 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001775void wait_task_inactive(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001776{
1777 unsigned long flags;
Ingo Molnardd41f592007-07-09 18:51:59 +02001778 int running, on_rq;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001779 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001780
Andi Kleen3a5c3592007-10-15 17:00:14 +02001781 for (;;) {
1782 /*
1783 * We do the initial early heuristics without holding
1784 * any task-queue locks at all. We'll only try to get
1785 * the runqueue lock when things look like they will
1786 * work out!
1787 */
1788 rq = task_rq(p);
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001789
Andi Kleen3a5c3592007-10-15 17:00:14 +02001790 /*
1791 * If the task is actively running on another CPU
1792 * still, just relax and busy-wait without holding
1793 * any locks.
1794 *
1795 * NOTE! Since we don't hold any locks, it's not
1796 * even sure that "rq" stays as the right runqueue!
1797 * But we don't care, since "task_running()" will
1798 * return false if the runqueue has changed and p
1799 * is actually now running somewhere else!
1800 */
1801 while (task_running(rq, p))
1802 cpu_relax();
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001803
Andi Kleen3a5c3592007-10-15 17:00:14 +02001804 /*
1805 * Ok, time to look more closely! We need the rq
1806 * lock now, to be *sure*. If we're wrong, we'll
1807 * just go back and repeat.
1808 */
1809 rq = task_rq_lock(p, &flags);
1810 running = task_running(rq, p);
1811 on_rq = p->se.on_rq;
1812 task_rq_unlock(rq, &flags);
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001813
Andi Kleen3a5c3592007-10-15 17:00:14 +02001814 /*
1815 * Was it really running after all now that we
1816 * checked with the proper locks actually held?
1817 *
1818 * Oops. Go back and try again..
1819 */
1820 if (unlikely(running)) {
1821 cpu_relax();
1822 continue;
1823 }
1824
1825 /*
1826 * It's not enough that it's not actively running,
1827 * it must be off the runqueue _entirely_, and not
1828 * preempted!
1829 *
1830 * So if it wa still runnable (but just not actively
1831 * running right now), it's preempted, and we should
1832 * yield - it could be a while.
1833 */
1834 if (unlikely(on_rq)) {
1835 schedule_timeout_uninterruptible(1);
1836 continue;
1837 }
1838
1839 /*
1840 * Ahh, all good. It wasn't running, and it wasn't
1841 * runnable, which means that it will never become
1842 * running in the future either. We're all done!
1843 */
1844 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001845 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001846}
1847
1848/***
1849 * kick_process - kick a running thread to enter/exit the kernel
1850 * @p: the to-be-kicked thread
1851 *
1852 * Cause a process which is running on another CPU to enter
1853 * kernel-mode, without any delay. (to get signals handled.)
1854 *
1855 * NOTE: this function doesnt have to take the runqueue lock,
1856 * because all it wants to ensure is that the remote task enters
1857 * the kernel. If the IPI races and the task has been migrated
1858 * to another CPU then no harm is done and the purpose has been
1859 * achieved as well.
1860 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001861void kick_process(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001862{
1863 int cpu;
1864
1865 preempt_disable();
1866 cpu = task_cpu(p);
1867 if ((cpu != smp_processor_id()) && task_curr(p))
1868 smp_send_reschedule(cpu);
1869 preempt_enable();
1870}
1871
1872/*
Peter Williams2dd73a42006-06-27 02:54:34 -07001873 * Return a low guess at the load of a migration-source cpu weighted
1874 * according to the scheduling class and "nice" value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001875 *
1876 * We want to under-estimate the load of migration sources, to
1877 * balance conservatively.
1878 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02001879static unsigned long source_load(int cpu, int type)
Con Kolivasb9104722005-11-08 21:38:55 -08001880{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001881 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001882 unsigned long total = weighted_cpuload(cpu);
Nick Piggina2000572006-02-10 01:51:02 -08001883
Peter Williams2dd73a42006-06-27 02:54:34 -07001884 if (type == 0)
Ingo Molnardd41f592007-07-09 18:51:59 +02001885 return total;
Peter Williams2dd73a42006-06-27 02:54:34 -07001886
Ingo Molnardd41f592007-07-09 18:51:59 +02001887 return min(rq->cpu_load[type-1], total);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888}
1889
1890/*
Peter Williams2dd73a42006-06-27 02:54:34 -07001891 * Return a high guess at the load of a migration-target cpu weighted
1892 * according to the scheduling class and "nice" value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001893 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02001894static unsigned long target_load(int cpu, int type)
Con Kolivasb9104722005-11-08 21:38:55 -08001895{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001896 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001897 unsigned long total = weighted_cpuload(cpu);
Nick Piggina2000572006-02-10 01:51:02 -08001898
Peter Williams2dd73a42006-06-27 02:54:34 -07001899 if (type == 0)
Ingo Molnardd41f592007-07-09 18:51:59 +02001900 return total;
Peter Williams2dd73a42006-06-27 02:54:34 -07001901
Ingo Molnardd41f592007-07-09 18:51:59 +02001902 return max(rq->cpu_load[type-1], total);
Peter Williams2dd73a42006-06-27 02:54:34 -07001903}
1904
1905/*
1906 * Return the average load per task on the cpu's run queue
1907 */
Gregory Haskinse7693a32008-01-25 21:08:09 +01001908static unsigned long cpu_avg_load_per_task(int cpu)
Peter Williams2dd73a42006-06-27 02:54:34 -07001909{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001910 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001911 unsigned long total = weighted_cpuload(cpu);
Peter Williams2dd73a42006-06-27 02:54:34 -07001912 unsigned long n = rq->nr_running;
1913
Ingo Molnardd41f592007-07-09 18:51:59 +02001914 return n ? total / n : SCHED_LOAD_SCALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001915}
1916
Nick Piggin147cbb42005-06-25 14:57:19 -07001917/*
1918 * find_idlest_group finds and returns the least busy CPU group within the
1919 * domain.
1920 */
1921static struct sched_group *
1922find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
1923{
1924 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
1925 unsigned long min_load = ULONG_MAX, this_load = 0;
1926 int load_idx = sd->forkexec_idx;
1927 int imbalance = 100 + (sd->imbalance_pct-100)/2;
1928
1929 do {
1930 unsigned long load, avg_load;
1931 int local_group;
1932 int i;
1933
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001934 /* Skip over this group if it has no CPUs allowed */
1935 if (!cpus_intersects(group->cpumask, p->cpus_allowed))
Andi Kleen3a5c3592007-10-15 17:00:14 +02001936 continue;
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001937
Nick Piggin147cbb42005-06-25 14:57:19 -07001938 local_group = cpu_isset(this_cpu, group->cpumask);
Nick Piggin147cbb42005-06-25 14:57:19 -07001939
1940 /* Tally up the load of all CPUs in the group */
1941 avg_load = 0;
1942
1943 for_each_cpu_mask(i, group->cpumask) {
1944 /* Bias balancing toward cpus of our domain */
1945 if (local_group)
1946 load = source_load(i, load_idx);
1947 else
1948 load = target_load(i, load_idx);
1949
1950 avg_load += load;
1951 }
1952
1953 /* Adjust by relative CPU power of the group */
Eric Dumazet5517d862007-05-08 00:32:57 -07001954 avg_load = sg_div_cpu_power(group,
1955 avg_load * SCHED_LOAD_SCALE);
Nick Piggin147cbb42005-06-25 14:57:19 -07001956
1957 if (local_group) {
1958 this_load = avg_load;
1959 this = group;
1960 } else if (avg_load < min_load) {
1961 min_load = avg_load;
1962 idlest = group;
1963 }
Andi Kleen3a5c3592007-10-15 17:00:14 +02001964 } while (group = group->next, group != sd->groups);
Nick Piggin147cbb42005-06-25 14:57:19 -07001965
1966 if (!idlest || 100*this_load < imbalance*min_load)
1967 return NULL;
1968 return idlest;
1969}
1970
1971/*
Satoru Takeuchi0feaece2006-10-03 01:14:10 -07001972 * find_idlest_cpu - find the idlest cpu among the cpus in group.
Nick Piggin147cbb42005-06-25 14:57:19 -07001973 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07001974static int
Mike Travis7c16ec52008-04-04 18:11:11 -07001975find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu,
1976 cpumask_t *tmp)
Nick Piggin147cbb42005-06-25 14:57:19 -07001977{
1978 unsigned long load, min_load = ULONG_MAX;
1979 int idlest = -1;
1980 int i;
1981
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001982 /* Traverse only the allowed CPUs */
Mike Travis7c16ec52008-04-04 18:11:11 -07001983 cpus_and(*tmp, group->cpumask, p->cpus_allowed);
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001984
Mike Travis7c16ec52008-04-04 18:11:11 -07001985 for_each_cpu_mask(i, *tmp) {
Peter Williams2dd73a42006-06-27 02:54:34 -07001986 load = weighted_cpuload(i);
Nick Piggin147cbb42005-06-25 14:57:19 -07001987
1988 if (load < min_load || (load == min_load && i == this_cpu)) {
1989 min_load = load;
1990 idlest = i;
1991 }
1992 }
1993
1994 return idlest;
1995}
1996
Nick Piggin476d1392005-06-25 14:57:29 -07001997/*
1998 * sched_balance_self: balance the current task (running on cpu) in domains
1999 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
2000 * SD_BALANCE_EXEC.
2001 *
2002 * Balance, ie. select the least loaded group.
2003 *
2004 * Returns the target CPU number, or the same CPU if no balancing is needed.
2005 *
2006 * preempt must be disabled.
2007 */
2008static int sched_balance_self(int cpu, int flag)
2009{
2010 struct task_struct *t = current;
2011 struct sched_domain *tmp, *sd = NULL;
Nick Piggin147cbb42005-06-25 14:57:19 -07002012
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002013 for_each_domain(cpu, tmp) {
Ingo Molnar9761eea2007-07-09 18:52:00 +02002014 /*
2015 * If power savings logic is enabled for a domain, stop there.
2016 */
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002017 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
2018 break;
Nick Piggin476d1392005-06-25 14:57:29 -07002019 if (tmp->flags & flag)
2020 sd = tmp;
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002021 }
Nick Piggin476d1392005-06-25 14:57:29 -07002022
2023 while (sd) {
Mike Travis7c16ec52008-04-04 18:11:11 -07002024 cpumask_t span, tmpmask;
Nick Piggin476d1392005-06-25 14:57:29 -07002025 struct sched_group *group;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07002026 int new_cpu, weight;
2027
2028 if (!(sd->flags & flag)) {
2029 sd = sd->child;
2030 continue;
2031 }
Nick Piggin476d1392005-06-25 14:57:29 -07002032
2033 span = sd->span;
2034 group = find_idlest_group(sd, t, cpu);
Siddha, Suresh B1a848872006-10-03 01:14:08 -07002035 if (!group) {
2036 sd = sd->child;
2037 continue;
2038 }
Nick Piggin476d1392005-06-25 14:57:29 -07002039
Mike Travis7c16ec52008-04-04 18:11:11 -07002040 new_cpu = find_idlest_cpu(group, t, cpu, &tmpmask);
Siddha, Suresh B1a848872006-10-03 01:14:08 -07002041 if (new_cpu == -1 || new_cpu == cpu) {
2042 /* Now try balancing at a lower domain level of cpu */
2043 sd = sd->child;
2044 continue;
2045 }
Nick Piggin476d1392005-06-25 14:57:29 -07002046
Siddha, Suresh B1a848872006-10-03 01:14:08 -07002047 /* Now try balancing at a lower domain level of new_cpu */
Nick Piggin476d1392005-06-25 14:57:29 -07002048 cpu = new_cpu;
Nick Piggin476d1392005-06-25 14:57:29 -07002049 sd = NULL;
2050 weight = cpus_weight(span);
2051 for_each_domain(cpu, tmp) {
2052 if (weight <= cpus_weight(tmp->span))
2053 break;
2054 if (tmp->flags & flag)
2055 sd = tmp;
2056 }
2057 /* while loop will break here if sd == NULL */
2058 }
2059
2060 return cpu;
2061}
2062
2063#endif /* CONFIG_SMP */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002064
Linus Torvalds1da177e2005-04-16 15:20:36 -07002065/***
2066 * try_to_wake_up - wake up a thread
2067 * @p: the to-be-woken-up thread
2068 * @state: the mask of task states that can be woken
2069 * @sync: do a synchronous wakeup?
2070 *
2071 * Put it on the run-queue if it's not already there. The "current"
2072 * thread is always on the run-queue (except when the actual
2073 * re-schedule is in progress), and as such you're allowed to do
2074 * the simpler "current->state = TASK_RUNNING" to mark yourself
2075 * runnable without the overhead of this.
2076 *
2077 * returns failure only if the task is already active.
2078 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07002079static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002080{
Ingo Molnarcc367732007-10-15 17:00:18 +02002081 int cpu, orig_cpu, this_cpu, success = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002082 unsigned long flags;
2083 long old_state;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002084 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002085
Ingo Molnarb85d0662008-03-16 20:03:22 +01002086 if (!sched_feat(SYNC_WAKEUPS))
2087 sync = 0;
2088
Linus Torvalds04e2f172008-02-23 18:05:03 -08002089 smp_wmb();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002090 rq = task_rq_lock(p, &flags);
2091 old_state = p->state;
2092 if (!(old_state & state))
2093 goto out;
2094
Ingo Molnardd41f592007-07-09 18:51:59 +02002095 if (p->se.on_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002096 goto out_running;
2097
2098 cpu = task_cpu(p);
Ingo Molnarcc367732007-10-15 17:00:18 +02002099 orig_cpu = cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002100 this_cpu = smp_processor_id();
2101
2102#ifdef CONFIG_SMP
2103 if (unlikely(task_running(rq, p)))
2104 goto out_activate;
2105
Dmitry Adamushko5d2f5a62008-01-25 21:08:21 +01002106 cpu = p->sched_class->select_task_rq(p, sync);
2107 if (cpu != orig_cpu) {
2108 set_task_cpu(p, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002109 task_rq_unlock(rq, &flags);
2110 /* might preempt at this point */
2111 rq = task_rq_lock(p, &flags);
2112 old_state = p->state;
2113 if (!(old_state & state))
2114 goto out;
Ingo Molnardd41f592007-07-09 18:51:59 +02002115 if (p->se.on_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002116 goto out_running;
2117
2118 this_cpu = smp_processor_id();
2119 cpu = task_cpu(p);
2120 }
2121
Gregory Haskinse7693a32008-01-25 21:08:09 +01002122#ifdef CONFIG_SCHEDSTATS
2123 schedstat_inc(rq, ttwu_count);
2124 if (cpu == this_cpu)
2125 schedstat_inc(rq, ttwu_local);
2126 else {
2127 struct sched_domain *sd;
2128 for_each_domain(this_cpu, sd) {
2129 if (cpu_isset(cpu, sd->span)) {
2130 schedstat_inc(sd, ttwu_wake_remote);
2131 break;
2132 }
2133 }
2134 }
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02002135#endif /* CONFIG_SCHEDSTATS */
Gregory Haskinse7693a32008-01-25 21:08:09 +01002136
Linus Torvalds1da177e2005-04-16 15:20:36 -07002137out_activate:
2138#endif /* CONFIG_SMP */
Ingo Molnarcc367732007-10-15 17:00:18 +02002139 schedstat_inc(p, se.nr_wakeups);
2140 if (sync)
2141 schedstat_inc(p, se.nr_wakeups_sync);
2142 if (orig_cpu != cpu)
2143 schedstat_inc(p, se.nr_wakeups_migrate);
2144 if (cpu == this_cpu)
2145 schedstat_inc(p, se.nr_wakeups_local);
2146 else
2147 schedstat_inc(p, se.nr_wakeups_remote);
Ingo Molnar2daa3572007-08-09 11:16:51 +02002148 update_rq_clock(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02002149 activate_task(rq, p, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002150 success = 1;
2151
2152out_running:
Ingo Molnar4ae7d5c2008-03-19 01:42:00 +01002153 check_preempt_curr(rq, p);
2154
Linus Torvalds1da177e2005-04-16 15:20:36 -07002155 p->state = TASK_RUNNING;
Steven Rostedt9a897c52008-01-25 21:08:22 +01002156#ifdef CONFIG_SMP
2157 if (p->sched_class->task_wake_up)
2158 p->sched_class->task_wake_up(rq, p);
2159#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160out:
2161 task_rq_unlock(rq, &flags);
2162
2163 return success;
2164}
2165
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08002166int wake_up_process(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002167{
Matthew Wilcoxd9514f62007-12-06 11:07:07 -05002168 return try_to_wake_up(p, TASK_ALL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002169}
Linus Torvalds1da177e2005-04-16 15:20:36 -07002170EXPORT_SYMBOL(wake_up_process);
2171
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08002172int wake_up_state(struct task_struct *p, unsigned int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002173{
2174 return try_to_wake_up(p, state, 0);
2175}
2176
Linus Torvalds1da177e2005-04-16 15:20:36 -07002177/*
2178 * Perform scheduler related setup for a newly forked process p.
2179 * p is forked by current.
Ingo Molnardd41f592007-07-09 18:51:59 +02002180 *
2181 * __sched_fork() is basic setup used by init_idle() too:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002182 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002183static void __sched_fork(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002184{
Ingo Molnardd41f592007-07-09 18:51:59 +02002185 p->se.exec_start = 0;
2186 p->se.sum_exec_runtime = 0;
Ingo Molnarf6cf8912007-08-28 12:53:24 +02002187 p->se.prev_sum_exec_runtime = 0;
Ingo Molnar4ae7d5c2008-03-19 01:42:00 +01002188 p->se.last_wakeup = 0;
2189 p->se.avg_overlap = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02002190
2191#ifdef CONFIG_SCHEDSTATS
2192 p->se.wait_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02002193 p->se.sum_sleep_runtime = 0;
2194 p->se.sleep_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02002195 p->se.block_start = 0;
2196 p->se.sleep_max = 0;
2197 p->se.block_max = 0;
2198 p->se.exec_max = 0;
Ingo Molnareba1ed42007-10-15 17:00:02 +02002199 p->se.slice_max = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02002200 p->se.wait_max = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02002201#endif
Nick Piggin476d1392005-06-25 14:57:29 -07002202
Peter Zijlstrafa717062008-01-25 21:08:27 +01002203 INIT_LIST_HEAD(&p->rt.run_list);
Ingo Molnardd41f592007-07-09 18:51:59 +02002204 p->se.on_rq = 0;
Peter Zijlstra4a55bd52008-04-19 19:45:00 +02002205 INIT_LIST_HEAD(&p->se.group_node);
Nick Piggin476d1392005-06-25 14:57:29 -07002206
Avi Kivitye107be32007-07-26 13:40:43 +02002207#ifdef CONFIG_PREEMPT_NOTIFIERS
2208 INIT_HLIST_HEAD(&p->preempt_notifiers);
2209#endif
2210
Linus Torvalds1da177e2005-04-16 15:20:36 -07002211 /*
2212 * We mark the process as running here, but have not actually
2213 * inserted it onto the runqueue yet. This guarantees that
2214 * nobody will actually run it, and a signal or other external
2215 * event cannot wake it up and insert it on the runqueue either.
2216 */
2217 p->state = TASK_RUNNING;
Ingo Molnardd41f592007-07-09 18:51:59 +02002218}
2219
2220/*
2221 * fork()/clone()-time setup:
2222 */
2223void sched_fork(struct task_struct *p, int clone_flags)
2224{
2225 int cpu = get_cpu();
2226
2227 __sched_fork(p);
2228
2229#ifdef CONFIG_SMP
2230 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
2231#endif
Ingo Molnar02e4bac2007-10-15 17:00:11 +02002232 set_task_cpu(p, cpu);
Ingo Molnarb29739f2006-06-27 02:54:51 -07002233
2234 /*
2235 * Make sure we do not leak PI boosting priority to the child:
2236 */
2237 p->prio = current->normal_prio;
Hiroshi Shimamoto2ddbf952007-10-15 17:00:11 +02002238 if (!rt_prio(p->prio))
2239 p->sched_class = &fair_sched_class;
Ingo Molnarb29739f2006-06-27 02:54:51 -07002240
Chandra Seetharaman52f17b62006-07-14 00:24:38 -07002241#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
Ingo Molnardd41f592007-07-09 18:51:59 +02002242 if (likely(sched_info_on()))
Chandra Seetharaman52f17b62006-07-14 00:24:38 -07002243 memset(&p->sched_info, 0, sizeof(p->sched_info));
Linus Torvalds1da177e2005-04-16 15:20:36 -07002244#endif
Chen, Kenneth Wd6077cb2006-02-14 13:53:10 -08002245#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
Nick Piggin4866cde2005-06-25 14:57:23 -07002246 p->oncpu = 0;
2247#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002248#ifdef CONFIG_PREEMPT
Nick Piggin4866cde2005-06-25 14:57:23 -07002249 /* Want to start with kernel preemption disabled. */
Al Viroa1261f52005-11-13 16:06:55 -08002250 task_thread_info(p)->preempt_count = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002251#endif
Nick Piggin476d1392005-06-25 14:57:29 -07002252 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -07002253}
2254
2255/*
2256 * wake_up_new_task - wake up a newly created task for the first time.
2257 *
2258 * This function will do some initial scheduler statistics housekeeping
2259 * that must be done for every newly created context, then puts the task
2260 * on the runqueue and wakes it.
2261 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08002262void wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002263{
2264 unsigned long flags;
Ingo Molnardd41f592007-07-09 18:51:59 +02002265 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002266
2267 rq = task_rq_lock(p, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002268 BUG_ON(p->state != TASK_RUNNING);
Ingo Molnara8e504d2007-08-09 11:16:47 +02002269 update_rq_clock(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002270
2271 p->prio = effective_prio(p);
2272
Srivatsa Vaddagirib9dca1e2007-10-17 16:55:11 +02002273 if (!p->sched_class->task_new || !current->se.on_rq) {
Ingo Molnardd41f592007-07-09 18:51:59 +02002274 activate_task(rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002275 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002276 /*
Ingo Molnardd41f592007-07-09 18:51:59 +02002277 * Let the scheduling class do new task startup
2278 * management (if any):
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279 */
Ingo Molnaree0827d2007-08-09 11:16:49 +02002280 p->sched_class->task_new(rq, p);
Ingo Molnar6363ca52008-05-29 11:28:57 +02002281 inc_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002282 }
Ingo Molnardd41f592007-07-09 18:51:59 +02002283 check_preempt_curr(rq, p);
Steven Rostedt9a897c52008-01-25 21:08:22 +01002284#ifdef CONFIG_SMP
2285 if (p->sched_class->task_wake_up)
2286 p->sched_class->task_wake_up(rq, p);
2287#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02002288 task_rq_unlock(rq, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002289}
2290
Avi Kivitye107be32007-07-26 13:40:43 +02002291#ifdef CONFIG_PREEMPT_NOTIFIERS
2292
2293/**
Randy Dunlap421cee22007-07-31 00:37:50 -07002294 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
2295 * @notifier: notifier struct to register
Avi Kivitye107be32007-07-26 13:40:43 +02002296 */
2297void preempt_notifier_register(struct preempt_notifier *notifier)
2298{
2299 hlist_add_head(&notifier->link, &current->preempt_notifiers);
2300}
2301EXPORT_SYMBOL_GPL(preempt_notifier_register);
2302
2303/**
2304 * preempt_notifier_unregister - no longer interested in preemption notifications
Randy Dunlap421cee22007-07-31 00:37:50 -07002305 * @notifier: notifier struct to unregister
Avi Kivitye107be32007-07-26 13:40:43 +02002306 *
2307 * This is safe to call from within a preemption notifier.
2308 */
2309void preempt_notifier_unregister(struct preempt_notifier *notifier)
2310{
2311 hlist_del(&notifier->link);
2312}
2313EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
2314
2315static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2316{
2317 struct preempt_notifier *notifier;
2318 struct hlist_node *node;
2319
2320 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2321 notifier->ops->sched_in(notifier, raw_smp_processor_id());
2322}
2323
2324static void
2325fire_sched_out_preempt_notifiers(struct task_struct *curr,
2326 struct task_struct *next)
2327{
2328 struct preempt_notifier *notifier;
2329 struct hlist_node *node;
2330
2331 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
2332 notifier->ops->sched_out(notifier, next);
2333}
2334
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02002335#else /* !CONFIG_PREEMPT_NOTIFIERS */
Avi Kivitye107be32007-07-26 13:40:43 +02002336
2337static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
2338{
2339}
2340
2341static void
2342fire_sched_out_preempt_notifiers(struct task_struct *curr,
2343 struct task_struct *next)
2344{
2345}
2346
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02002347#endif /* CONFIG_PREEMPT_NOTIFIERS */
Avi Kivitye107be32007-07-26 13:40:43 +02002348
Linus Torvalds1da177e2005-04-16 15:20:36 -07002349/**
Nick Piggin4866cde2005-06-25 14:57:23 -07002350 * prepare_task_switch - prepare to switch tasks
2351 * @rq: the runqueue preparing to switch
Randy Dunlap421cee22007-07-31 00:37:50 -07002352 * @prev: the current task that is being switched out
Nick Piggin4866cde2005-06-25 14:57:23 -07002353 * @next: the task we are going to switch to.
2354 *
2355 * This is called with the rq lock held and interrupts off. It must
2356 * be paired with a subsequent finish_task_switch after the context
2357 * switch.
2358 *
2359 * prepare_task_switch sets up locking and calls architecture specific
2360 * hooks.
2361 */
Avi Kivitye107be32007-07-26 13:40:43 +02002362static inline void
2363prepare_task_switch(struct rq *rq, struct task_struct *prev,
2364 struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -07002365{
Avi Kivitye107be32007-07-26 13:40:43 +02002366 fire_sched_out_preempt_notifiers(prev, next);
Nick Piggin4866cde2005-06-25 14:57:23 -07002367 prepare_lock_switch(rq, next);
2368 prepare_arch_switch(next);
2369}
2370
2371/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002372 * finish_task_switch - clean up after a task-switch
Jeff Garzik344baba2005-09-07 01:15:17 -04002373 * @rq: runqueue associated with task-switch
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374 * @prev: the thread we just switched away from.
2375 *
Nick Piggin4866cde2005-06-25 14:57:23 -07002376 * finish_task_switch must be called after the context switch, paired
2377 * with a prepare_task_switch call before the context switch.
2378 * finish_task_switch will reconcile locking set up by prepare_task_switch,
2379 * and do any other architecture-specific cleanup actions.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002380 *
2381 * Note that we may have delayed dropping an mm in context_switch(). If
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01002382 * so, we finish that here outside of the runqueue lock. (Doing it
Linus Torvalds1da177e2005-04-16 15:20:36 -07002383 * with the lock held can cause deadlocks; see schedule() for
2384 * details.)
2385 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02002386static void finish_task_switch(struct rq *rq, struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002387 __releases(rq->lock)
2388{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002389 struct mm_struct *mm = rq->prev_mm;
Oleg Nesterov55a101f2006-09-29 02:01:10 -07002390 long prev_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002391
2392 rq->prev_mm = NULL;
2393
2394 /*
2395 * A task struct has one reference for the use as "current".
Oleg Nesterovc394cc92006-09-29 02:01:11 -07002396 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
Oleg Nesterov55a101f2006-09-29 02:01:10 -07002397 * schedule one last time. The schedule call will never return, and
2398 * the scheduled task must drop that reference.
Oleg Nesterovc394cc92006-09-29 02:01:11 -07002399 * The test for TASK_DEAD must occur while the runqueue locks are
Linus Torvalds1da177e2005-04-16 15:20:36 -07002400 * still held, otherwise prev could be scheduled on another cpu, die
2401 * there before we look at prev->state, and then the reference would
2402 * be dropped twice.
2403 * Manfred Spraul <manfred@colorfullife.com>
2404 */
Oleg Nesterov55a101f2006-09-29 02:01:10 -07002405 prev_state = prev->state;
Nick Piggin4866cde2005-06-25 14:57:23 -07002406 finish_arch_switch(prev);
2407 finish_lock_switch(rq, prev);
Steven Rostedt9a897c52008-01-25 21:08:22 +01002408#ifdef CONFIG_SMP
2409 if (current->sched_class->post_schedule)
2410 current->sched_class->post_schedule(rq);
2411#endif
Steven Rostedte8fa1362008-01-25 21:08:05 +01002412
Avi Kivitye107be32007-07-26 13:40:43 +02002413 fire_sched_in_preempt_notifiers(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002414 if (mm)
2415 mmdrop(mm);
Oleg Nesterovc394cc92006-09-29 02:01:11 -07002416 if (unlikely(prev_state == TASK_DEAD)) {
bibo maoc6fd91f2006-03-26 01:38:20 -08002417 /*
2418 * Remove function-return probe instances associated with this
2419 * task and put them back on the free list.
Ingo Molnar9761eea2007-07-09 18:52:00 +02002420 */
bibo maoc6fd91f2006-03-26 01:38:20 -08002421 kprobe_flush_task(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002422 put_task_struct(prev);
bibo maoc6fd91f2006-03-26 01:38:20 -08002423 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002424}
2425
2426/**
2427 * schedule_tail - first thing a freshly forked thread must call.
2428 * @prev: the thread we just switched away from.
2429 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07002430asmlinkage void schedule_tail(struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002431 __releases(rq->lock)
2432{
Ingo Molnar70b97a72006-07-03 00:25:42 -07002433 struct rq *rq = this_rq();
2434
Nick Piggin4866cde2005-06-25 14:57:23 -07002435 finish_task_switch(rq, prev);
2436#ifdef __ARCH_WANT_UNLOCKED_CTXSW
2437 /* In this case, finish_task_switch does not reenable preemption */
2438 preempt_enable();
2439#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002440 if (current->set_child_tid)
Pavel Emelyanovb4888932007-10-18 23:40:14 -07002441 put_user(task_pid_vnr(current), current->set_child_tid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002442}
2443
2444/*
2445 * context_switch - switch to the new MM and the new
2446 * thread's register state.
2447 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002448static inline void
Ingo Molnar70b97a72006-07-03 00:25:42 -07002449context_switch(struct rq *rq, struct task_struct *prev,
Ingo Molnar36c8b582006-07-03 00:25:41 -07002450 struct task_struct *next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002451{
Ingo Molnardd41f592007-07-09 18:51:59 +02002452 struct mm_struct *mm, *oldmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002453
Avi Kivitye107be32007-07-26 13:40:43 +02002454 prepare_task_switch(rq, prev, next);
Ingo Molnardd41f592007-07-09 18:51:59 +02002455 mm = next->mm;
2456 oldmm = prev->active_mm;
Zachary Amsden9226d122007-02-13 13:26:21 +01002457 /*
2458 * For paravirt, this is coupled with an exit in switch_to to
2459 * combine the page table reload and the switch backend into
2460 * one hypercall.
2461 */
2462 arch_enter_lazy_cpu_mode();
2463
Ingo Molnardd41f592007-07-09 18:51:59 +02002464 if (unlikely(!mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002465 next->active_mm = oldmm;
2466 atomic_inc(&oldmm->mm_count);
2467 enter_lazy_tlb(oldmm, next);
2468 } else
2469 switch_mm(oldmm, mm, next);
2470
Ingo Molnardd41f592007-07-09 18:51:59 +02002471 if (unlikely(!prev->mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002472 prev->active_mm = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002473 rq->prev_mm = oldmm;
2474 }
Ingo Molnar3a5f5e42006-07-14 00:24:27 -07002475 /*
2476 * Since the runqueue lock will be released by the next
2477 * task (which is an invalid locking op but in the case
2478 * of the scheduler it's an obvious special-case), so we
2479 * do an early lockdep release here:
2480 */
2481#ifndef __ARCH_WANT_UNLOCKED_CTXSW
Ingo Molnar8a25d5d2006-07-03 00:24:54 -07002482 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
Ingo Molnar3a5f5e42006-07-14 00:24:27 -07002483#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002484
2485 /* Here we just switch the register state and the stack. */
2486 switch_to(prev, next, prev);
2487
Ingo Molnardd41f592007-07-09 18:51:59 +02002488 barrier();
2489 /*
2490 * this_rq must be evaluated again because prev may have moved
2491 * CPUs since it called schedule(), thus the 'rq' on its stack
2492 * frame will be invalid.
2493 */
2494 finish_task_switch(this_rq(), prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002495}
2496
2497/*
2498 * nr_running, nr_uninterruptible and nr_context_switches:
2499 *
2500 * externally visible scheduler statistics: current number of runnable
2501 * threads, current number of uninterruptible-sleeping threads, total
2502 * number of context switches performed since bootup.
2503 */
2504unsigned long nr_running(void)
2505{
2506 unsigned long i, sum = 0;
2507
2508 for_each_online_cpu(i)
2509 sum += cpu_rq(i)->nr_running;
2510
2511 return sum;
2512}
2513
2514unsigned long nr_uninterruptible(void)
2515{
2516 unsigned long i, sum = 0;
2517
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08002518 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002519 sum += cpu_rq(i)->nr_uninterruptible;
2520
2521 /*
2522 * Since we read the counters lockless, it might be slightly
2523 * inaccurate. Do not allow it to go below zero though:
2524 */
2525 if (unlikely((long)sum < 0))
2526 sum = 0;
2527
2528 return sum;
2529}
2530
2531unsigned long long nr_context_switches(void)
2532{
Steven Rostedtcc94abf2006-06-27 02:54:31 -07002533 int i;
2534 unsigned long long sum = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002535
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08002536 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002537 sum += cpu_rq(i)->nr_switches;
2538
2539 return sum;
2540}
2541
2542unsigned long nr_iowait(void)
2543{
2544 unsigned long i, sum = 0;
2545
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08002546 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002547 sum += atomic_read(&cpu_rq(i)->nr_iowait);
2548
2549 return sum;
2550}
2551
Jack Steinerdb1b1fe2006-03-31 02:31:21 -08002552unsigned long nr_active(void)
2553{
2554 unsigned long i, running = 0, uninterruptible = 0;
2555
2556 for_each_online_cpu(i) {
2557 running += cpu_rq(i)->nr_running;
2558 uninterruptible += cpu_rq(i)->nr_uninterruptible;
2559 }
2560
2561 if (unlikely((long)uninterruptible < 0))
2562 uninterruptible = 0;
2563
2564 return running + uninterruptible;
2565}
2566
Linus Torvalds1da177e2005-04-16 15:20:36 -07002567/*
Ingo Molnardd41f592007-07-09 18:51:59 +02002568 * Update rq->cpu_load[] statistics. This function is usually called every
2569 * scheduler tick (TICK_NSEC).
Ingo Molnar48f24c42006-07-03 00:25:40 -07002570 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002571static void update_cpu_load(struct rq *this_rq)
Ingo Molnar48f24c42006-07-03 00:25:40 -07002572{
Dmitry Adamushko495eca42007-10-15 17:00:06 +02002573 unsigned long this_load = this_rq->load.weight;
Ingo Molnardd41f592007-07-09 18:51:59 +02002574 int i, scale;
2575
2576 this_rq->nr_load_updates++;
Ingo Molnardd41f592007-07-09 18:51:59 +02002577
2578 /* Update our load: */
2579 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2580 unsigned long old_load, new_load;
2581
2582 /* scale is effectively 1 << i now, and >> i divides by scale */
2583
2584 old_load = this_rq->cpu_load[i];
2585 new_load = this_load;
Ingo Molnara25707f2007-10-15 17:00:03 +02002586 /*
2587 * Round up the averaging division if load is increasing. This
2588 * prevents us from getting stuck on 9 if the load is 10, for
2589 * example.
2590 */
2591 if (new_load > old_load)
2592 new_load += scale-1;
Ingo Molnardd41f592007-07-09 18:51:59 +02002593 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2594 }
Ingo Molnar48f24c42006-07-03 00:25:40 -07002595}
2596
Ingo Molnardd41f592007-07-09 18:51:59 +02002597#ifdef CONFIG_SMP
2598
Ingo Molnar48f24c42006-07-03 00:25:40 -07002599/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002600 * double_rq_lock - safely lock two runqueues
2601 *
2602 * Note this does not disable interrupts like task_rq_lock,
2603 * you need to do so manually before calling.
2604 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002605static void double_rq_lock(struct rq *rq1, struct rq *rq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002606 __acquires(rq1->lock)
2607 __acquires(rq2->lock)
2608{
Kirill Korotaev054b9102006-12-10 02:20:11 -08002609 BUG_ON(!irqs_disabled());
Linus Torvalds1da177e2005-04-16 15:20:36 -07002610 if (rq1 == rq2) {
2611 spin_lock(&rq1->lock);
2612 __acquire(rq2->lock); /* Fake it out ;) */
2613 } else {
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002614 if (rq1 < rq2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002615 spin_lock(&rq1->lock);
2616 spin_lock(&rq2->lock);
2617 } else {
2618 spin_lock(&rq2->lock);
2619 spin_lock(&rq1->lock);
2620 }
2621 }
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02002622 update_rq_clock(rq1);
2623 update_rq_clock(rq2);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002624}
2625
2626/*
2627 * double_rq_unlock - safely unlock two runqueues
2628 *
2629 * Note this does not restore interrupts like task_rq_unlock,
2630 * you need to do so manually after calling.
2631 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002632static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002633 __releases(rq1->lock)
2634 __releases(rq2->lock)
2635{
2636 spin_unlock(&rq1->lock);
2637 if (rq1 != rq2)
2638 spin_unlock(&rq2->lock);
2639 else
2640 __release(rq2->lock);
2641}
2642
2643/*
2644 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2645 */
Steven Rostedte8fa1362008-01-25 21:08:05 +01002646static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002647 __releases(this_rq->lock)
2648 __acquires(busiest->lock)
2649 __acquires(this_rq->lock)
2650{
Steven Rostedte8fa1362008-01-25 21:08:05 +01002651 int ret = 0;
2652
Kirill Korotaev054b9102006-12-10 02:20:11 -08002653 if (unlikely(!irqs_disabled())) {
2654 /* printk() doesn't work good under rq->lock */
2655 spin_unlock(&this_rq->lock);
2656 BUG_ON(1);
2657 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002658 if (unlikely(!spin_trylock(&busiest->lock))) {
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002659 if (busiest < this_rq) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002660 spin_unlock(&this_rq->lock);
2661 spin_lock(&busiest->lock);
2662 spin_lock(&this_rq->lock);
Steven Rostedte8fa1362008-01-25 21:08:05 +01002663 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002664 } else
2665 spin_lock(&busiest->lock);
2666 }
Steven Rostedte8fa1362008-01-25 21:08:05 +01002667 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002668}
2669
2670/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002671 * If dest_cpu is allowed for this process, migrate the task to it.
2672 * This is accomplished by forcing the cpu_allowed mask to only
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01002673 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
Linus Torvalds1da177e2005-04-16 15:20:36 -07002674 * the cpu_allowed mask is restored.
2675 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07002676static void sched_migrate_task(struct task_struct *p, int dest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002677{
Ingo Molnar70b97a72006-07-03 00:25:42 -07002678 struct migration_req req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002679 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002680 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002681
2682 rq = task_rq_lock(p, &flags);
2683 if (!cpu_isset(dest_cpu, p->cpus_allowed)
2684 || unlikely(cpu_is_offline(dest_cpu)))
2685 goto out;
2686
2687 /* force the process onto the specified CPU */
2688 if (migrate_task(p, dest_cpu, &req)) {
2689 /* Need to wait for migration thread (might exit: take ref). */
2690 struct task_struct *mt = rq->migration_thread;
Ingo Molnar36c8b582006-07-03 00:25:41 -07002691
Linus Torvalds1da177e2005-04-16 15:20:36 -07002692 get_task_struct(mt);
2693 task_rq_unlock(rq, &flags);
2694 wake_up_process(mt);
2695 put_task_struct(mt);
2696 wait_for_completion(&req.done);
Ingo Molnar36c8b582006-07-03 00:25:41 -07002697
Linus Torvalds1da177e2005-04-16 15:20:36 -07002698 return;
2699 }
2700out:
2701 task_rq_unlock(rq, &flags);
2702}
2703
2704/*
Nick Piggin476d1392005-06-25 14:57:29 -07002705 * sched_exec - execve() is a valuable balancing opportunity, because at
2706 * this point the task has the smallest effective memory and cache footprint.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002707 */
2708void sched_exec(void)
2709{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002710 int new_cpu, this_cpu = get_cpu();
Nick Piggin476d1392005-06-25 14:57:29 -07002711 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002712 put_cpu();
Nick Piggin476d1392005-06-25 14:57:29 -07002713 if (new_cpu != this_cpu)
2714 sched_migrate_task(current, new_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002715}
2716
2717/*
2718 * pull_task - move a task from a remote runqueue to the local runqueue.
2719 * Both runqueues must be locked.
2720 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002721static void pull_task(struct rq *src_rq, struct task_struct *p,
2722 struct rq *this_rq, int this_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002723{
Ingo Molnar2e1cb742007-08-09 11:16:49 +02002724 deactivate_task(src_rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002725 set_task_cpu(p, this_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02002726 activate_task(this_rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002727 /*
2728 * Note that idle threads have a prio of MAX_PRIO, for this test
2729 * to be always true for them.
2730 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002731 check_preempt_curr(this_rq, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002732}
2733
2734/*
2735 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2736 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08002737static
Ingo Molnar70b97a72006-07-03 00:25:42 -07002738int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002739 struct sched_domain *sd, enum cpu_idle_type idle,
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07002740 int *all_pinned)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002741{
2742 /*
2743 * We do not migrate tasks that are:
2744 * 1) running (obviously), or
2745 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2746 * 3) are cache-hot on their current CPU.
2747 */
Ingo Molnarcc367732007-10-15 17:00:18 +02002748 if (!cpu_isset(this_cpu, p->cpus_allowed)) {
2749 schedstat_inc(p, se.nr_failed_migrations_affine);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002750 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002751 }
Nick Piggin81026792005-06-25 14:57:07 -07002752 *all_pinned = 0;
2753
Ingo Molnarcc367732007-10-15 17:00:18 +02002754 if (task_running(rq, p)) {
2755 schedstat_inc(p, se.nr_failed_migrations_running);
Nick Piggin81026792005-06-25 14:57:07 -07002756 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002757 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002758
Ingo Molnarda84d962007-10-15 17:00:18 +02002759 /*
2760 * Aggressive migration if:
2761 * 1) task is cache cold, or
2762 * 2) too many balance attempts have failed.
2763 */
2764
Ingo Molnar6bc16652007-10-15 17:00:18 +02002765 if (!task_hot(p, rq->clock, sd) ||
2766 sd->nr_balance_failed > sd->cache_nice_tries) {
Ingo Molnarda84d962007-10-15 17:00:18 +02002767#ifdef CONFIG_SCHEDSTATS
Ingo Molnarcc367732007-10-15 17:00:18 +02002768 if (task_hot(p, rq->clock, sd)) {
Ingo Molnarda84d962007-10-15 17:00:18 +02002769 schedstat_inc(sd, lb_hot_gained[idle]);
Ingo Molnarcc367732007-10-15 17:00:18 +02002770 schedstat_inc(p, se.nr_forced_migrations);
2771 }
Ingo Molnarda84d962007-10-15 17:00:18 +02002772#endif
2773 return 1;
2774 }
2775
Ingo Molnarcc367732007-10-15 17:00:18 +02002776 if (task_hot(p, rq->clock, sd)) {
2777 schedstat_inc(p, se.nr_failed_migrations_hot);
Ingo Molnarda84d962007-10-15 17:00:18 +02002778 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002779 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002780 return 1;
2781}
2782
Peter Williamse1d14842007-10-24 18:23:51 +02002783static unsigned long
2784balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2785 unsigned long max_load_move, struct sched_domain *sd,
2786 enum cpu_idle_type idle, int *all_pinned,
2787 int *this_best_prio, struct rq_iterator *iterator)
Ingo Molnardd41f592007-07-09 18:51:59 +02002788{
Peter Zijlstrab82d9fd2007-11-09 22:39:39 +01002789 int loops = 0, pulled = 0, pinned = 0, skip_for_load;
Ingo Molnardd41f592007-07-09 18:51:59 +02002790 struct task_struct *p;
2791 long rem_load_move = max_load_move;
2792
Peter Williamse1d14842007-10-24 18:23:51 +02002793 if (max_load_move == 0)
Ingo Molnardd41f592007-07-09 18:51:59 +02002794 goto out;
2795
2796 pinned = 1;
2797
2798 /*
2799 * Start the load-balancing iterator:
2800 */
2801 p = iterator->start(iterator->arg);
2802next:
Peter Zijlstrab82d9fd2007-11-09 22:39:39 +01002803 if (!p || loops++ > sysctl_sched_nr_migrate)
Ingo Molnardd41f592007-07-09 18:51:59 +02002804 goto out;
2805 /*
Peter Zijlstrab82d9fd2007-11-09 22:39:39 +01002806 * To help distribute high priority tasks across CPUs we don't
Ingo Molnardd41f592007-07-09 18:51:59 +02002807 * skip a task if it will be the highest priority task (i.e. smallest
2808 * prio value) on its new queue regardless of its load weight
2809 */
2810 skip_for_load = (p->se.load.weight >> 1) > rem_load_move +
2811 SCHED_LOAD_SCALE_FUZZ;
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002812 if ((skip_for_load && p->prio >= *this_best_prio) ||
Ingo Molnardd41f592007-07-09 18:51:59 +02002813 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
Ingo Molnardd41f592007-07-09 18:51:59 +02002814 p = iterator->next(iterator->arg);
2815 goto next;
2816 }
2817
2818 pull_task(busiest, p, this_rq, this_cpu);
2819 pulled++;
2820 rem_load_move -= p->se.load.weight;
2821
2822 /*
Peter Zijlstrab82d9fd2007-11-09 22:39:39 +01002823 * We only want to steal up to the prescribed amount of weighted load.
Ingo Molnardd41f592007-07-09 18:51:59 +02002824 */
Peter Williamse1d14842007-10-24 18:23:51 +02002825 if (rem_load_move > 0) {
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002826 if (p->prio < *this_best_prio)
2827 *this_best_prio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02002828 p = iterator->next(iterator->arg);
2829 goto next;
2830 }
2831out:
2832 /*
Peter Williamse1d14842007-10-24 18:23:51 +02002833 * Right now, this is one of only two places pull_task() is called,
Ingo Molnardd41f592007-07-09 18:51:59 +02002834 * so we can safely collect pull_task() stats here rather than
2835 * inside pull_task().
2836 */
2837 schedstat_add(sd, lb_gained[idle], pulled);
2838
2839 if (all_pinned)
2840 *all_pinned = pinned;
Peter Williamse1d14842007-10-24 18:23:51 +02002841
2842 return max_load_move - rem_load_move;
Ingo Molnardd41f592007-07-09 18:51:59 +02002843}
Ingo Molnar48f24c42006-07-03 00:25:40 -07002844
Linus Torvalds1da177e2005-04-16 15:20:36 -07002845/*
Peter Williams43010652007-08-09 11:16:46 +02002846 * move_tasks tries to move up to max_load_move weighted load from busiest to
2847 * this_rq, as part of a balancing operation within domain "sd".
2848 * Returns 1 if successful and 0 otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002849 *
2850 * Called with both runqueues locked.
2851 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002852static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
Peter Williams43010652007-08-09 11:16:46 +02002853 unsigned long max_load_move,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002854 struct sched_domain *sd, enum cpu_idle_type idle,
Peter Williams2dd73a42006-06-27 02:54:34 -07002855 int *all_pinned)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002856{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02002857 const struct sched_class *class = sched_class_highest;
Peter Williams43010652007-08-09 11:16:46 +02002858 unsigned long total_load_moved = 0;
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002859 int this_best_prio = this_rq->curr->prio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002860
Ingo Molnardd41f592007-07-09 18:51:59 +02002861 do {
Peter Williams43010652007-08-09 11:16:46 +02002862 total_load_moved +=
2863 class->load_balance(this_rq, this_cpu, busiest,
Peter Williamse1d14842007-10-24 18:23:51 +02002864 max_load_move - total_load_moved,
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002865 sd, idle, all_pinned, &this_best_prio);
Ingo Molnardd41f592007-07-09 18:51:59 +02002866 class = class->next;
Peter Williams43010652007-08-09 11:16:46 +02002867 } while (class && max_load_move > total_load_moved);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002868
Peter Williams43010652007-08-09 11:16:46 +02002869 return total_load_moved > 0;
2870}
2871
Peter Williamse1d14842007-10-24 18:23:51 +02002872static int
2873iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
2874 struct sched_domain *sd, enum cpu_idle_type idle,
2875 struct rq_iterator *iterator)
2876{
2877 struct task_struct *p = iterator->start(iterator->arg);
2878 int pinned = 0;
2879
2880 while (p) {
2881 if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
2882 pull_task(busiest, p, this_rq, this_cpu);
2883 /*
2884 * Right now, this is only the second place pull_task()
2885 * is called, so we can safely collect pull_task()
2886 * stats here rather than inside pull_task().
2887 */
2888 schedstat_inc(sd, lb_gained[idle]);
2889
2890 return 1;
2891 }
2892 p = iterator->next(iterator->arg);
2893 }
2894
2895 return 0;
2896}
2897
Peter Williams43010652007-08-09 11:16:46 +02002898/*
2899 * move_one_task tries to move exactly one task from busiest to this_rq, as
2900 * part of active balancing operations within "domain".
2901 * Returns 1 if successful and 0 otherwise.
2902 *
2903 * Called with both runqueues locked.
2904 */
2905static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
2906 struct sched_domain *sd, enum cpu_idle_type idle)
2907{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02002908 const struct sched_class *class;
Peter Williams43010652007-08-09 11:16:46 +02002909
2910 for (class = sched_class_highest; class; class = class->next)
Peter Williamse1d14842007-10-24 18:23:51 +02002911 if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle))
Peter Williams43010652007-08-09 11:16:46 +02002912 return 1;
2913
2914 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002915}
2916
2917/*
2918 * find_busiest_group finds and returns the busiest CPU group within the
Ingo Molnar48f24c42006-07-03 00:25:40 -07002919 * domain. It calculates and returns the amount of weighted load which
2920 * should be moved to restore balance via the imbalance parameter.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002921 */
2922static struct sched_group *
2923find_busiest_group(struct sched_domain *sd, int this_cpu,
Ingo Molnardd41f592007-07-09 18:51:59 +02002924 unsigned long *imbalance, enum cpu_idle_type idle,
Mike Travis7c16ec52008-04-04 18:11:11 -07002925 int *sd_idle, const cpumask_t *cpus, int *balance)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002926{
2927 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
2928 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07002929 unsigned long max_pull;
Peter Williams2dd73a42006-06-27 02:54:34 -07002930 unsigned long busiest_load_per_task, busiest_nr_running;
2931 unsigned long this_load_per_task, this_nr_running;
Ken Chen908a7c12007-10-17 16:55:11 +02002932 int load_idx, group_imb = 0;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002933#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2934 int power_savings_balance = 1;
2935 unsigned long leader_nr_running = 0, min_load_per_task = 0;
2936 unsigned long min_nr_running = ULONG_MAX;
2937 struct sched_group *group_min = NULL, *group_leader = NULL;
2938#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002939
2940 max_load = this_load = total_load = total_pwr = 0;
Peter Williams2dd73a42006-06-27 02:54:34 -07002941 busiest_load_per_task = busiest_nr_running = 0;
2942 this_load_per_task = this_nr_running = 0;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002943 if (idle == CPU_NOT_IDLE)
Nick Piggin78979862005-06-25 14:57:13 -07002944 load_idx = sd->busy_idx;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002945 else if (idle == CPU_NEWLY_IDLE)
Nick Piggin78979862005-06-25 14:57:13 -07002946 load_idx = sd->newidle_idx;
2947 else
2948 load_idx = sd->idle_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002949
2950 do {
Ken Chen908a7c12007-10-17 16:55:11 +02002951 unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002952 int local_group;
2953 int i;
Ken Chen908a7c12007-10-17 16:55:11 +02002954 int __group_imb = 0;
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002955 unsigned int balance_cpu = -1, first_idle_cpu = 0;
Peter Williams2dd73a42006-06-27 02:54:34 -07002956 unsigned long sum_nr_running, sum_weighted_load;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002957
2958 local_group = cpu_isset(this_cpu, group->cpumask);
2959
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002960 if (local_group)
2961 balance_cpu = first_cpu(group->cpumask);
2962
Linus Torvalds1da177e2005-04-16 15:20:36 -07002963 /* Tally up the load of all CPUs in the group */
Peter Williams2dd73a42006-06-27 02:54:34 -07002964 sum_weighted_load = sum_nr_running = avg_load = 0;
Ken Chen908a7c12007-10-17 16:55:11 +02002965 max_cpu_load = 0;
2966 min_cpu_load = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002967
2968 for_each_cpu_mask(i, group->cpumask) {
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002969 struct rq *rq;
2970
2971 if (!cpu_isset(i, *cpus))
2972 continue;
2973
2974 rq = cpu_rq(i);
Peter Williams2dd73a42006-06-27 02:54:34 -07002975
Suresh Siddha9439aab2007-07-19 21:28:35 +02002976 if (*sd_idle && rq->nr_running)
Nick Piggin5969fe02005-09-10 00:26:19 -07002977 *sd_idle = 0;
2978
Linus Torvalds1da177e2005-04-16 15:20:36 -07002979 /* Bias balancing toward cpus of our domain */
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002980 if (local_group) {
2981 if (idle_cpu(i) && !first_idle_cpu) {
2982 first_idle_cpu = 1;
2983 balance_cpu = i;
2984 }
2985
Nick Piggina2000572006-02-10 01:51:02 -08002986 load = target_load(i, load_idx);
Ken Chen908a7c12007-10-17 16:55:11 +02002987 } else {
Nick Piggina2000572006-02-10 01:51:02 -08002988 load = source_load(i, load_idx);
Ken Chen908a7c12007-10-17 16:55:11 +02002989 if (load > max_cpu_load)
2990 max_cpu_load = load;
2991 if (min_cpu_load > load)
2992 min_cpu_load = load;
2993 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002994
2995 avg_load += load;
Peter Williams2dd73a42006-06-27 02:54:34 -07002996 sum_nr_running += rq->nr_running;
Ingo Molnardd41f592007-07-09 18:51:59 +02002997 sum_weighted_load += weighted_cpuload(i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002998 }
2999
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003000 /*
3001 * First idle cpu or the first cpu(busiest) in this sched group
3002 * is eligible for doing load balancing at this and above
Suresh Siddha9439aab2007-07-19 21:28:35 +02003003 * domains. In the newly idle case, we will allow all the cpu's
3004 * to do the newly idle load balance.
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003005 */
Suresh Siddha9439aab2007-07-19 21:28:35 +02003006 if (idle != CPU_NEWLY_IDLE && local_group &&
3007 balance_cpu != this_cpu && balance) {
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003008 *balance = 0;
3009 goto ret;
3010 }
3011
Linus Torvalds1da177e2005-04-16 15:20:36 -07003012 total_load += avg_load;
Eric Dumazet5517d862007-05-08 00:32:57 -07003013 total_pwr += group->__cpu_power;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003014
3015 /* Adjust by relative CPU power of the group */
Eric Dumazet5517d862007-05-08 00:32:57 -07003016 avg_load = sg_div_cpu_power(group,
3017 avg_load * SCHED_LOAD_SCALE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003018
Ken Chen908a7c12007-10-17 16:55:11 +02003019 if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE)
3020 __group_imb = 1;
3021
Eric Dumazet5517d862007-05-08 00:32:57 -07003022 group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003023
Linus Torvalds1da177e2005-04-16 15:20:36 -07003024 if (local_group) {
3025 this_load = avg_load;
3026 this = group;
Peter Williams2dd73a42006-06-27 02:54:34 -07003027 this_nr_running = sum_nr_running;
3028 this_load_per_task = sum_weighted_load;
3029 } else if (avg_load > max_load &&
Ken Chen908a7c12007-10-17 16:55:11 +02003030 (sum_nr_running > group_capacity || __group_imb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003031 max_load = avg_load;
3032 busiest = group;
Peter Williams2dd73a42006-06-27 02:54:34 -07003033 busiest_nr_running = sum_nr_running;
3034 busiest_load_per_task = sum_weighted_load;
Ken Chen908a7c12007-10-17 16:55:11 +02003035 group_imb = __group_imb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003036 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003037
3038#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
3039 /*
3040 * Busy processors will not participate in power savings
3041 * balance.
3042 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003043 if (idle == CPU_NOT_IDLE ||
3044 !(sd->flags & SD_POWERSAVINGS_BALANCE))
3045 goto group_next;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003046
3047 /*
3048 * If the local group is idle or completely loaded
3049 * no need to do power savings balance at this domain
3050 */
3051 if (local_group && (this_nr_running >= group_capacity ||
3052 !this_nr_running))
3053 power_savings_balance = 0;
3054
Ingo Molnardd41f592007-07-09 18:51:59 +02003055 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003056 * If a group is already running at full capacity or idle,
3057 * don't include that group in power savings calculations
Ingo Molnardd41f592007-07-09 18:51:59 +02003058 */
3059 if (!power_savings_balance || sum_nr_running >= group_capacity
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003060 || !sum_nr_running)
Ingo Molnardd41f592007-07-09 18:51:59 +02003061 goto group_next;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003062
Ingo Molnardd41f592007-07-09 18:51:59 +02003063 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003064 * Calculate the group which has the least non-idle load.
Ingo Molnardd41f592007-07-09 18:51:59 +02003065 * This is the group from where we need to pick up the load
3066 * for saving power
3067 */
3068 if ((sum_nr_running < min_nr_running) ||
3069 (sum_nr_running == min_nr_running &&
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003070 first_cpu(group->cpumask) <
3071 first_cpu(group_min->cpumask))) {
Ingo Molnardd41f592007-07-09 18:51:59 +02003072 group_min = group;
3073 min_nr_running = sum_nr_running;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003074 min_load_per_task = sum_weighted_load /
3075 sum_nr_running;
Ingo Molnardd41f592007-07-09 18:51:59 +02003076 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003077
Ingo Molnardd41f592007-07-09 18:51:59 +02003078 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003079 * Calculate the group which is almost near its
Ingo Molnardd41f592007-07-09 18:51:59 +02003080 * capacity but still has some space to pick up some load
3081 * from other group and save more power
3082 */
3083 if (sum_nr_running <= group_capacity - 1) {
3084 if (sum_nr_running > leader_nr_running ||
3085 (sum_nr_running == leader_nr_running &&
3086 first_cpu(group->cpumask) >
3087 first_cpu(group_leader->cpumask))) {
3088 group_leader = group;
3089 leader_nr_running = sum_nr_running;
3090 }
Ingo Molnar48f24c42006-07-03 00:25:40 -07003091 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003092group_next:
3093#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07003094 group = group->next;
3095 } while (group != sd->groups);
3096
Peter Williams2dd73a42006-06-27 02:54:34 -07003097 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003098 goto out_balanced;
3099
3100 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
3101
3102 if (this_load >= avg_load ||
3103 100*max_load <= sd->imbalance_pct*this_load)
3104 goto out_balanced;
3105
Peter Williams2dd73a42006-06-27 02:54:34 -07003106 busiest_load_per_task /= busiest_nr_running;
Ken Chen908a7c12007-10-17 16:55:11 +02003107 if (group_imb)
3108 busiest_load_per_task = min(busiest_load_per_task, avg_load);
3109
Linus Torvalds1da177e2005-04-16 15:20:36 -07003110 /*
3111 * We're trying to get all the cpus to the average_load, so we don't
3112 * want to push ourselves above the average load, nor do we wish to
3113 * reduce the max loaded cpu below the average load, as either of these
3114 * actions would just result in more rebalancing later, and ping-pong
3115 * tasks around. Thus we look for the minimum possible imbalance.
3116 * Negative imbalances (*we* are more loaded than anyone else) will
3117 * be counted as no imbalance for these purposes -- we can't fix that
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01003118 * by pulling tasks to us. Be careful of negative numbers as they'll
Linus Torvalds1da177e2005-04-16 15:20:36 -07003119 * appear as very large values with unsigned longs.
3120 */
Peter Williams2dd73a42006-06-27 02:54:34 -07003121 if (max_load <= busiest_load_per_task)
3122 goto out_balanced;
3123
3124 /*
3125 * In the presence of smp nice balancing, certain scenarios can have
3126 * max load less than avg load(as we skip the groups at or below
3127 * its cpu_power, while calculating max_load..)
3128 */
3129 if (max_load < avg_load) {
3130 *imbalance = 0;
3131 goto small_imbalance;
3132 }
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07003133
3134 /* Don't want to pull so many tasks that a group would go idle */
Peter Williams2dd73a42006-06-27 02:54:34 -07003135 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07003136
Linus Torvalds1da177e2005-04-16 15:20:36 -07003137 /* How much load to actually move to equalise the imbalance */
Eric Dumazet5517d862007-05-08 00:32:57 -07003138 *imbalance = min(max_pull * busiest->__cpu_power,
3139 (avg_load - this_load) * this->__cpu_power)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003140 / SCHED_LOAD_SCALE;
3141
Peter Williams2dd73a42006-06-27 02:54:34 -07003142 /*
3143 * if *imbalance is less than the average load per runnable task
3144 * there is no gaurantee that any tasks will be moved so we'll have
3145 * a think about bumping its value to force at least one task to be
3146 * moved
3147 */
Suresh Siddha7fd0d2d2007-09-05 14:32:48 +02003148 if (*imbalance < busiest_load_per_task) {
Ingo Molnar48f24c42006-07-03 00:25:40 -07003149 unsigned long tmp, pwr_now, pwr_move;
Peter Williams2dd73a42006-06-27 02:54:34 -07003150 unsigned int imbn;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003151
Peter Williams2dd73a42006-06-27 02:54:34 -07003152small_imbalance:
3153 pwr_move = pwr_now = 0;
3154 imbn = 2;
3155 if (this_nr_running) {
3156 this_load_per_task /= this_nr_running;
3157 if (busiest_load_per_task > this_load_per_task)
3158 imbn = 1;
3159 } else
3160 this_load_per_task = SCHED_LOAD_SCALE;
3161
Ingo Molnardd41f592007-07-09 18:51:59 +02003162 if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
3163 busiest_load_per_task * imbn) {
Peter Williams2dd73a42006-06-27 02:54:34 -07003164 *imbalance = busiest_load_per_task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003165 return busiest;
3166 }
3167
3168 /*
3169 * OK, we don't have enough imbalance to justify moving tasks,
3170 * however we may be able to increase total CPU power used by
3171 * moving them.
3172 */
3173
Eric Dumazet5517d862007-05-08 00:32:57 -07003174 pwr_now += busiest->__cpu_power *
3175 min(busiest_load_per_task, max_load);
3176 pwr_now += this->__cpu_power *
3177 min(this_load_per_task, this_load);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003178 pwr_now /= SCHED_LOAD_SCALE;
3179
3180 /* Amount of load we'd subtract */
Eric Dumazet5517d862007-05-08 00:32:57 -07003181 tmp = sg_div_cpu_power(busiest,
3182 busiest_load_per_task * SCHED_LOAD_SCALE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003183 if (max_load > tmp)
Eric Dumazet5517d862007-05-08 00:32:57 -07003184 pwr_move += busiest->__cpu_power *
Peter Williams2dd73a42006-06-27 02:54:34 -07003185 min(busiest_load_per_task, max_load - tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003186
3187 /* Amount of load we'd add */
Eric Dumazet5517d862007-05-08 00:32:57 -07003188 if (max_load * busiest->__cpu_power <
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08003189 busiest_load_per_task * SCHED_LOAD_SCALE)
Eric Dumazet5517d862007-05-08 00:32:57 -07003190 tmp = sg_div_cpu_power(this,
3191 max_load * busiest->__cpu_power);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003192 else
Eric Dumazet5517d862007-05-08 00:32:57 -07003193 tmp = sg_div_cpu_power(this,
3194 busiest_load_per_task * SCHED_LOAD_SCALE);
3195 pwr_move += this->__cpu_power *
3196 min(this_load_per_task, this_load + tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003197 pwr_move /= SCHED_LOAD_SCALE;
3198
3199 /* Move if we gain throughput */
Suresh Siddha7fd0d2d2007-09-05 14:32:48 +02003200 if (pwr_move > pwr_now)
3201 *imbalance = busiest_load_per_task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003202 }
3203
Linus Torvalds1da177e2005-04-16 15:20:36 -07003204 return busiest;
3205
3206out_balanced:
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003207#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003208 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003209 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003210
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003211 if (this == group_leader && group_leader != group_min) {
3212 *imbalance = min_load_per_task;
3213 return group_min;
3214 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07003215#endif
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003216ret:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003217 *imbalance = 0;
3218 return NULL;
3219}
3220
3221/*
3222 * find_busiest_queue - find the busiest runqueue among the cpus in group.
3223 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003224static struct rq *
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003225find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
Mike Travis7c16ec52008-04-04 18:11:11 -07003226 unsigned long imbalance, const cpumask_t *cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003227{
Ingo Molnar70b97a72006-07-03 00:25:42 -07003228 struct rq *busiest = NULL, *rq;
Peter Williams2dd73a42006-06-27 02:54:34 -07003229 unsigned long max_load = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003230 int i;
3231
3232 for_each_cpu_mask(i, group->cpumask) {
Ingo Molnardd41f592007-07-09 18:51:59 +02003233 unsigned long wl;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003234
3235 if (!cpu_isset(i, *cpus))
3236 continue;
3237
Ingo Molnar48f24c42006-07-03 00:25:40 -07003238 rq = cpu_rq(i);
Ingo Molnardd41f592007-07-09 18:51:59 +02003239 wl = weighted_cpuload(i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003240
Ingo Molnardd41f592007-07-09 18:51:59 +02003241 if (rq->nr_running == 1 && wl > imbalance)
Peter Williams2dd73a42006-06-27 02:54:34 -07003242 continue;
3243
Ingo Molnardd41f592007-07-09 18:51:59 +02003244 if (wl > max_load) {
3245 max_load = wl;
Ingo Molnar48f24c42006-07-03 00:25:40 -07003246 busiest = rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003247 }
3248 }
3249
3250 return busiest;
3251}
3252
3253/*
Nick Piggin77391d72005-06-25 14:57:30 -07003254 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
3255 * so long as it is large enough.
3256 */
3257#define MAX_PINNED_INTERVAL 512
3258
3259/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003260 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3261 * tasks if there is an imbalance.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003262 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003263static int load_balance(int this_cpu, struct rq *this_rq,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003264 struct sched_domain *sd, enum cpu_idle_type idle,
Mike Travis7c16ec52008-04-04 18:11:11 -07003265 int *balance, cpumask_t *cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003266{
Peter Williams43010652007-08-09 11:16:46 +02003267 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003268 struct sched_group *group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003269 unsigned long imbalance;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003270 struct rq *busiest;
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003271 unsigned long flags;
Nick Piggin5969fe02005-09-10 00:26:19 -07003272
Mike Travis7c16ec52008-04-04 18:11:11 -07003273 cpus_setall(*cpus);
3274
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003275 /*
3276 * When power savings policy is enabled for the parent domain, idle
3277 * sibling can pick up load irrespective of busy siblings. In this case,
Ingo Molnardd41f592007-07-09 18:51:59 +02003278 * let the state of idle sibling percolate up as CPU_IDLE, instead of
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003279 * portraying it as CPU_NOT_IDLE.
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003280 */
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003281 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003282 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07003283 sd_idle = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003284
Ingo Molnar2d723762007-10-15 17:00:12 +02003285 schedstat_inc(sd, lb_count[idle]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003286
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003287redo:
3288 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
Mike Travis7c16ec52008-04-04 18:11:11 -07003289 cpus, balance);
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003290
Chen, Kenneth W06066712006-12-10 02:20:35 -08003291 if (*balance == 0)
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003292 goto out_balanced;
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003293
Linus Torvalds1da177e2005-04-16 15:20:36 -07003294 if (!group) {
3295 schedstat_inc(sd, lb_nobusyg[idle]);
3296 goto out_balanced;
3297 }
3298
Mike Travis7c16ec52008-04-04 18:11:11 -07003299 busiest = find_busiest_queue(group, idle, imbalance, cpus);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003300 if (!busiest) {
3301 schedstat_inc(sd, lb_nobusyq[idle]);
3302 goto out_balanced;
3303 }
3304
Nick Piggindb935db2005-06-25 14:57:11 -07003305 BUG_ON(busiest == this_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003306
3307 schedstat_add(sd, lb_imbalance[idle], imbalance);
3308
Peter Williams43010652007-08-09 11:16:46 +02003309 ld_moved = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003310 if (busiest->nr_running > 1) {
3311 /*
3312 * Attempt to move tasks. If find_busiest_group has found
3313 * an imbalance but busiest->nr_running <= 1, the group is
Peter Williams43010652007-08-09 11:16:46 +02003314 * still unbalanced. ld_moved simply stays zero, so it is
Linus Torvalds1da177e2005-04-16 15:20:36 -07003315 * correctly treated as an imbalance.
3316 */
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003317 local_irq_save(flags);
Nick Piggine17224b2005-09-10 00:26:18 -07003318 double_rq_lock(this_rq, busiest);
Peter Williams43010652007-08-09 11:16:46 +02003319 ld_moved = move_tasks(this_rq, this_cpu, busiest,
Ingo Molnar48f24c42006-07-03 00:25:40 -07003320 imbalance, sd, idle, &all_pinned);
Nick Piggine17224b2005-09-10 00:26:18 -07003321 double_rq_unlock(this_rq, busiest);
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003322 local_irq_restore(flags);
Nick Piggin81026792005-06-25 14:57:07 -07003323
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003324 /*
3325 * some other cpu did the load balance for us.
3326 */
Peter Williams43010652007-08-09 11:16:46 +02003327 if (ld_moved && this_cpu != smp_processor_id())
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003328 resched_cpu(this_cpu);
3329
Nick Piggin81026792005-06-25 14:57:07 -07003330 /* All tasks on this runqueue were pinned by CPU affinity */
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003331 if (unlikely(all_pinned)) {
Mike Travis7c16ec52008-04-04 18:11:11 -07003332 cpu_clear(cpu_of(busiest), *cpus);
3333 if (!cpus_empty(*cpus))
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003334 goto redo;
Nick Piggin81026792005-06-25 14:57:07 -07003335 goto out_balanced;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003336 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003337 }
Nick Piggin81026792005-06-25 14:57:07 -07003338
Peter Williams43010652007-08-09 11:16:46 +02003339 if (!ld_moved) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003340 schedstat_inc(sd, lb_failed[idle]);
3341 sd->nr_balance_failed++;
3342
3343 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003344
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003345 spin_lock_irqsave(&busiest->lock, flags);
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07003346
3347 /* don't kick the migration_thread, if the curr
3348 * task on busiest cpu can't be moved to this_cpu
3349 */
3350 if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003351 spin_unlock_irqrestore(&busiest->lock, flags);
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07003352 all_pinned = 1;
3353 goto out_one_pinned;
3354 }
3355
Linus Torvalds1da177e2005-04-16 15:20:36 -07003356 if (!busiest->active_balance) {
3357 busiest->active_balance = 1;
3358 busiest->push_cpu = this_cpu;
Nick Piggin81026792005-06-25 14:57:07 -07003359 active_balance = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003360 }
Christoph Lameterfe2eea32006-12-10 02:20:21 -08003361 spin_unlock_irqrestore(&busiest->lock, flags);
Nick Piggin81026792005-06-25 14:57:07 -07003362 if (active_balance)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003363 wake_up_process(busiest->migration_thread);
3364
3365 /*
3366 * We've kicked active balancing, reset the failure
3367 * counter.
3368 */
Nick Piggin39507452005-06-25 14:57:09 -07003369 sd->nr_balance_failed = sd->cache_nice_tries+1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003370 }
Nick Piggin81026792005-06-25 14:57:07 -07003371 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07003372 sd->nr_balance_failed = 0;
3373
Nick Piggin81026792005-06-25 14:57:07 -07003374 if (likely(!active_balance)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003375 /* We were unbalanced, so reset the balancing interval */
3376 sd->balance_interval = sd->min_interval;
Nick Piggin81026792005-06-25 14:57:07 -07003377 } else {
3378 /*
3379 * If we've begun active balancing, start to back off. This
3380 * case may not be covered by the all_pinned logic if there
3381 * is only 1 task on the busy runqueue (because we don't call
3382 * move_tasks).
3383 */
3384 if (sd->balance_interval < sd->max_interval)
3385 sd->balance_interval *= 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003386 }
3387
Peter Williams43010652007-08-09 11:16:46 +02003388 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003389 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Ingo Molnar6363ca52008-05-29 11:28:57 +02003390 return -1;
3391 return ld_moved;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003392
3393out_balanced:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003394 schedstat_inc(sd, lb_balanced[idle]);
3395
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003396 sd->nr_balance_failed = 0;
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07003397
3398out_one_pinned:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003399 /* tune up the balancing interval */
Nick Piggin77391d72005-06-25 14:57:30 -07003400 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
3401 (sd->balance_interval < sd->max_interval))
Linus Torvalds1da177e2005-04-16 15:20:36 -07003402 sd->balance_interval *= 2;
3403
Ingo Molnar48f24c42006-07-03 00:25:40 -07003404 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003405 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Ingo Molnar6363ca52008-05-29 11:28:57 +02003406 return -1;
3407 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003408}
3409
3410/*
3411 * Check this_cpu to ensure it is balanced within domain. Attempt to move
3412 * tasks if there is an imbalance.
3413 *
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003414 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
Linus Torvalds1da177e2005-04-16 15:20:36 -07003415 * this_rq is locked.
3416 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07003417static int
Mike Travis7c16ec52008-04-04 18:11:11 -07003418load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
3419 cpumask_t *cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003420{
3421 struct sched_group *group;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003422 struct rq *busiest = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003423 unsigned long imbalance;
Peter Williams43010652007-08-09 11:16:46 +02003424 int ld_moved = 0;
Nick Piggin5969fe02005-09-10 00:26:19 -07003425 int sd_idle = 0;
Suresh Siddha969bb4e2007-07-19 21:28:35 +02003426 int all_pinned = 0;
Mike Travis7c16ec52008-04-04 18:11:11 -07003427
3428 cpus_setall(*cpus);
Nick Piggin5969fe02005-09-10 00:26:19 -07003429
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003430 /*
3431 * When power savings policy is enabled for the parent domain, idle
3432 * sibling can pick up load irrespective of busy siblings. In this case,
3433 * let the state of idle sibling percolate up as IDLE, instead of
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003434 * portraying it as CPU_NOT_IDLE.
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003435 */
3436 if (sd->flags & SD_SHARE_CPUPOWER &&
3437 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07003438 sd_idle = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003439
Ingo Molnar2d723762007-10-15 17:00:12 +02003440 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003441redo:
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003442 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
Mike Travis7c16ec52008-04-04 18:11:11 -07003443 &sd_idle, cpus, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003444 if (!group) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003445 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003446 goto out_balanced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003447 }
3448
Mike Travis7c16ec52008-04-04 18:11:11 -07003449 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus);
Nick Piggindb935db2005-06-25 14:57:11 -07003450 if (!busiest) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003451 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003452 goto out_balanced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003453 }
3454
Nick Piggindb935db2005-06-25 14:57:11 -07003455 BUG_ON(busiest == this_rq);
3456
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003457 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
Nick Piggind6d5cfa2005-09-10 00:26:16 -07003458
Peter Williams43010652007-08-09 11:16:46 +02003459 ld_moved = 0;
Nick Piggind6d5cfa2005-09-10 00:26:16 -07003460 if (busiest->nr_running > 1) {
3461 /* Attempt to move tasks */
3462 double_lock_balance(this_rq, busiest);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02003463 /* this_rq->clock is already updated */
3464 update_rq_clock(busiest);
Peter Williams43010652007-08-09 11:16:46 +02003465 ld_moved = move_tasks(this_rq, this_cpu, busiest,
Suresh Siddha969bb4e2007-07-19 21:28:35 +02003466 imbalance, sd, CPU_NEWLY_IDLE,
3467 &all_pinned);
Nick Piggind6d5cfa2005-09-10 00:26:16 -07003468 spin_unlock(&busiest->lock);
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003469
Suresh Siddha969bb4e2007-07-19 21:28:35 +02003470 if (unlikely(all_pinned)) {
Mike Travis7c16ec52008-04-04 18:11:11 -07003471 cpu_clear(cpu_of(busiest), *cpus);
3472 if (!cpus_empty(*cpus))
Christoph Lameter0a2966b2006-09-25 23:30:51 -07003473 goto redo;
3474 }
Nick Piggind6d5cfa2005-09-10 00:26:16 -07003475 }
3476
Peter Williams43010652007-08-09 11:16:46 +02003477 if (!ld_moved) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003478 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003479 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
3480 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07003481 return -1;
3482 } else
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003483 sd->nr_balance_failed = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003484
Peter Williams43010652007-08-09 11:16:46 +02003485 return ld_moved;
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003486
3487out_balanced:
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003488 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
Ingo Molnar48f24c42006-07-03 00:25:40 -07003489 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07003490 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07003491 return -1;
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003492 sd->nr_balance_failed = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07003493
Nick Piggin16cfb1c2005-06-25 14:57:08 -07003494 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003495}
3496
3497/*
3498 * idle_balance is called by schedule() if this_cpu is about to become
3499 * idle. Attempts to pull tasks from other CPUs.
3500 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003501static void idle_balance(int this_cpu, struct rq *this_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003502{
3503 struct sched_domain *sd;
Ingo Molnardd41f592007-07-09 18:51:59 +02003504 int pulled_task = -1;
3505 unsigned long next_balance = jiffies + HZ;
Mike Travis7c16ec52008-04-04 18:11:11 -07003506 cpumask_t tmpmask;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003507
3508 for_each_domain(this_cpu, sd) {
Christoph Lameter92c4ca52007-06-23 17:16:33 -07003509 unsigned long interval;
3510
3511 if (!(sd->flags & SD_LOAD_BALANCE))
3512 continue;
3513
3514 if (sd->flags & SD_BALANCE_NEWIDLE)
Ingo Molnar48f24c42006-07-03 00:25:40 -07003515 /* If we've pulled tasks over stop searching: */
Mike Travis7c16ec52008-04-04 18:11:11 -07003516 pulled_task = load_balance_newidle(this_cpu, this_rq,
3517 sd, &tmpmask);
Christoph Lameter92c4ca52007-06-23 17:16:33 -07003518
3519 interval = msecs_to_jiffies(sd->balance_interval);
3520 if (time_after(next_balance, sd->last_balance + interval))
3521 next_balance = sd->last_balance + interval;
3522 if (pulled_task)
3523 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003524 }
Ingo Molnardd41f592007-07-09 18:51:59 +02003525 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
Christoph Lameter1bd77f22006-12-10 02:20:27 -08003526 /*
3527 * We are going idle. next_balance may be set based on
3528 * a busy processor. So reset next_balance.
3529 */
3530 this_rq->next_balance = next_balance;
Ingo Molnardd41f592007-07-09 18:51:59 +02003531 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003532}
3533
3534/*
3535 * active_load_balance is run by migration threads. It pushes running tasks
3536 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
3537 * running on each physical CPU where possible, and avoids physical /
3538 * logical imbalances.
3539 *
3540 * Called with busiest_rq locked.
3541 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003542static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003543{
Nick Piggin39507452005-06-25 14:57:09 -07003544 int target_cpu = busiest_rq->push_cpu;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003545 struct sched_domain *sd;
3546 struct rq *target_rq;
Nick Piggin39507452005-06-25 14:57:09 -07003547
Ingo Molnar48f24c42006-07-03 00:25:40 -07003548 /* Is there any task to move? */
Nick Piggin39507452005-06-25 14:57:09 -07003549 if (busiest_rq->nr_running <= 1)
Nick Piggin39507452005-06-25 14:57:09 -07003550 return;
3551
3552 target_rq = cpu_rq(target_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003553
3554 /*
Nick Piggin39507452005-06-25 14:57:09 -07003555 * This condition is "impossible", if it occurs
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01003556 * we need to fix it. Originally reported by
Nick Piggin39507452005-06-25 14:57:09 -07003557 * Bjorn Helgaas on a 128-cpu setup.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003558 */
Nick Piggin39507452005-06-25 14:57:09 -07003559 BUG_ON(busiest_rq == target_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003560
Nick Piggin39507452005-06-25 14:57:09 -07003561 /* move a task from busiest_rq to target_rq */
3562 double_lock_balance(busiest_rq, target_rq);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02003563 update_rq_clock(busiest_rq);
3564 update_rq_clock(target_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003565
Nick Piggin39507452005-06-25 14:57:09 -07003566 /* Search for an sd spanning us and the target CPU. */
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07003567 for_each_domain(target_cpu, sd) {
Nick Piggin39507452005-06-25 14:57:09 -07003568 if ((sd->flags & SD_LOAD_BALANCE) &&
Ingo Molnar48f24c42006-07-03 00:25:40 -07003569 cpu_isset(busiest_cpu, sd->span))
Nick Piggin39507452005-06-25 14:57:09 -07003570 break;
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07003571 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003572
Ingo Molnar48f24c42006-07-03 00:25:40 -07003573 if (likely(sd)) {
Ingo Molnar2d723762007-10-15 17:00:12 +02003574 schedstat_inc(sd, alb_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003575
Peter Williams43010652007-08-09 11:16:46 +02003576 if (move_one_task(target_rq, target_cpu, busiest_rq,
3577 sd, CPU_IDLE))
Ingo Molnar48f24c42006-07-03 00:25:40 -07003578 schedstat_inc(sd, alb_pushed);
3579 else
3580 schedstat_inc(sd, alb_failed);
3581 }
Nick Piggin39507452005-06-25 14:57:09 -07003582 spin_unlock(&target_rq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003583}
3584
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003585#ifdef CONFIG_NO_HZ
3586static struct {
3587 atomic_t load_balancer;
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01003588 cpumask_t cpu_mask;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003589} nohz ____cacheline_aligned = {
3590 .load_balancer = ATOMIC_INIT(-1),
3591 .cpu_mask = CPU_MASK_NONE,
3592};
3593
Christoph Lameter7835b982006-12-10 02:20:22 -08003594/*
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003595 * This routine will try to nominate the ilb (idle load balancing)
3596 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3597 * load balancing on behalf of all those cpus. If all the cpus in the system
3598 * go into this tickless mode, then there will be no ilb owner (as there is
3599 * no need for one) and all the cpus will sleep till the next wakeup event
3600 * arrives...
Christoph Lameter7835b982006-12-10 02:20:22 -08003601 *
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003602 * For the ilb owner, tick is not stopped. And this tick will be used
3603 * for idle load balancing. ilb owner will still be part of
3604 * nohz.cpu_mask..
3605 *
3606 * While stopping the tick, this cpu will become the ilb owner if there
3607 * is no other owner. And will be the owner till that cpu becomes busy
3608 * or if all cpus in the system stop their ticks at which point
3609 * there is no need for ilb owner.
3610 *
3611 * When the ilb owner becomes busy, it nominates another owner, during the
3612 * next busy scheduler_tick()
3613 */
3614int select_nohz_load_balancer(int stop_tick)
3615{
3616 int cpu = smp_processor_id();
3617
3618 if (stop_tick) {
3619 cpu_set(cpu, nohz.cpu_mask);
3620 cpu_rq(cpu)->in_nohz_recently = 1;
3621
3622 /*
3623 * If we are going offline and still the leader, give up!
3624 */
3625 if (cpu_is_offline(cpu) &&
3626 atomic_read(&nohz.load_balancer) == cpu) {
3627 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3628 BUG();
3629 return 0;
3630 }
3631
3632 /* time for ilb owner also to sleep */
3633 if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3634 if (atomic_read(&nohz.load_balancer) == cpu)
3635 atomic_set(&nohz.load_balancer, -1);
3636 return 0;
3637 }
3638
3639 if (atomic_read(&nohz.load_balancer) == -1) {
3640 /* make me the ilb owner */
3641 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
3642 return 1;
3643 } else if (atomic_read(&nohz.load_balancer) == cpu)
3644 return 1;
3645 } else {
3646 if (!cpu_isset(cpu, nohz.cpu_mask))
3647 return 0;
3648
3649 cpu_clear(cpu, nohz.cpu_mask);
3650
3651 if (atomic_read(&nohz.load_balancer) == cpu)
3652 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3653 BUG();
3654 }
3655 return 0;
3656}
3657#endif
3658
3659static DEFINE_SPINLOCK(balancing);
3660
3661/*
Christoph Lameter7835b982006-12-10 02:20:22 -08003662 * It checks each scheduling domain to see if it is due to be balanced,
3663 * and initiates a balancing operation if so.
3664 *
3665 * Balancing parameters are set up in arch_init_sched_domains.
3666 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02003667static void rebalance_domains(int cpu, enum cpu_idle_type idle)
Christoph Lameter7835b982006-12-10 02:20:22 -08003668{
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003669 int balance = 1;
3670 struct rq *rq = cpu_rq(cpu);
Christoph Lameter7835b982006-12-10 02:20:22 -08003671 unsigned long interval;
3672 struct sched_domain *sd;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003673 /* Earliest time when we have to do rebalance again */
Christoph Lameterc9819f42006-12-10 02:20:25 -08003674 unsigned long next_balance = jiffies + 60*HZ;
Suresh Siddhaf549da82007-08-23 15:18:02 +02003675 int update_next_balance = 0;
Dmitry Adamushkod07355f2008-05-12 21:21:15 +02003676 int need_serialize;
Mike Travis7c16ec52008-04-04 18:11:11 -07003677 cpumask_t tmp;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003678
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003679 for_each_domain(cpu, sd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003680 if (!(sd->flags & SD_LOAD_BALANCE))
3681 continue;
3682
3683 interval = sd->balance_interval;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003684 if (idle != CPU_IDLE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003685 interval *= sd->busy_factor;
3686
3687 /* scale ms to jiffies */
3688 interval = msecs_to_jiffies(interval);
3689 if (unlikely(!interval))
3690 interval = 1;
Ingo Molnardd41f592007-07-09 18:51:59 +02003691 if (interval > HZ*NR_CPUS/10)
3692 interval = HZ*NR_CPUS/10;
3693
Dmitry Adamushkod07355f2008-05-12 21:21:15 +02003694 need_serialize = sd->flags & SD_SERIALIZE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003695
Dmitry Adamushkod07355f2008-05-12 21:21:15 +02003696 if (need_serialize) {
Christoph Lameter08c183f2006-12-10 02:20:29 -08003697 if (!spin_trylock(&balancing))
3698 goto out;
3699 }
3700
Christoph Lameterc9819f42006-12-10 02:20:25 -08003701 if (time_after_eq(jiffies, sd->last_balance + interval)) {
Mike Travis7c16ec52008-04-04 18:11:11 -07003702 if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) {
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07003703 /*
3704 * We've pulled tasks over so either we're no
Nick Piggin5969fe02005-09-10 00:26:19 -07003705 * longer idle, or one of our SMT siblings is
3706 * not idle.
3707 */
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003708 idle = CPU_NOT_IDLE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003709 }
Christoph Lameter1bd77f22006-12-10 02:20:27 -08003710 sd->last_balance = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003711 }
Dmitry Adamushkod07355f2008-05-12 21:21:15 +02003712 if (need_serialize)
Christoph Lameter08c183f2006-12-10 02:20:29 -08003713 spin_unlock(&balancing);
3714out:
Suresh Siddhaf549da82007-08-23 15:18:02 +02003715 if (time_after(next_balance, sd->last_balance + interval)) {
Christoph Lameterc9819f42006-12-10 02:20:25 -08003716 next_balance = sd->last_balance + interval;
Suresh Siddhaf549da82007-08-23 15:18:02 +02003717 update_next_balance = 1;
3718 }
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003719
3720 /*
3721 * Stop the load balance at this level. There is another
3722 * CPU in our sched group which is doing load balancing more
3723 * actively.
3724 */
3725 if (!balance)
3726 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003727 }
Suresh Siddhaf549da82007-08-23 15:18:02 +02003728
3729 /*
3730 * next_balance will be updated only when there is a need.
3731 * When the cpu is attached to null domain for ex, it will not be
3732 * updated.
3733 */
3734 if (likely(update_next_balance))
3735 rq->next_balance = next_balance;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003736}
3737
3738/*
3739 * run_rebalance_domains is triggered when needed from the scheduler tick.
3740 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3741 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3742 */
3743static void run_rebalance_domains(struct softirq_action *h)
3744{
Ingo Molnardd41f592007-07-09 18:51:59 +02003745 int this_cpu = smp_processor_id();
3746 struct rq *this_rq = cpu_rq(this_cpu);
3747 enum cpu_idle_type idle = this_rq->idle_at_tick ?
3748 CPU_IDLE : CPU_NOT_IDLE;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003749
Ingo Molnardd41f592007-07-09 18:51:59 +02003750 rebalance_domains(this_cpu, idle);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003751
3752#ifdef CONFIG_NO_HZ
3753 /*
3754 * If this cpu is the owner for idle load balancing, then do the
3755 * balancing on behalf of the other idle cpus whose ticks are
3756 * stopped.
3757 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003758 if (this_rq->idle_at_tick &&
3759 atomic_read(&nohz.load_balancer) == this_cpu) {
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003760 cpumask_t cpus = nohz.cpu_mask;
3761 struct rq *rq;
3762 int balance_cpu;
3763
Ingo Molnardd41f592007-07-09 18:51:59 +02003764 cpu_clear(this_cpu, cpus);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003765 for_each_cpu_mask(balance_cpu, cpus) {
3766 /*
3767 * If this cpu gets work to do, stop the load balancing
3768 * work being done for other cpus. Next load
3769 * balancing owner will pick it up.
3770 */
3771 if (need_resched())
3772 break;
3773
Oleg Nesterovde0cf892007-08-12 18:08:19 +02003774 rebalance_domains(balance_cpu, CPU_IDLE);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003775
3776 rq = cpu_rq(balance_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02003777 if (time_after(this_rq->next_balance, rq->next_balance))
3778 this_rq->next_balance = rq->next_balance;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003779 }
3780 }
3781#endif
3782}
3783
3784/*
3785 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3786 *
3787 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3788 * idle load balancing owner or decide to stop the periodic load balancing,
3789 * if the whole system is idle.
3790 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003791static inline void trigger_load_balance(struct rq *rq, int cpu)
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003792{
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003793#ifdef CONFIG_NO_HZ
3794 /*
3795 * If we were in the nohz mode recently and busy at the current
3796 * scheduler tick, then check if we need to nominate new idle
3797 * load balancer.
3798 */
3799 if (rq->in_nohz_recently && !rq->idle_at_tick) {
3800 rq->in_nohz_recently = 0;
3801
3802 if (atomic_read(&nohz.load_balancer) == cpu) {
3803 cpu_clear(cpu, nohz.cpu_mask);
3804 atomic_set(&nohz.load_balancer, -1);
3805 }
3806
3807 if (atomic_read(&nohz.load_balancer) == -1) {
3808 /*
3809 * simple selection for now: Nominate the
3810 * first cpu in the nohz list to be the next
3811 * ilb owner.
3812 *
3813 * TBD: Traverse the sched domains and nominate
3814 * the nearest cpu in the nohz.cpu_mask.
3815 */
3816 int ilb = first_cpu(nohz.cpu_mask);
3817
Mike Travis434d53b2008-04-04 18:11:04 -07003818 if (ilb < nr_cpu_ids)
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003819 resched_cpu(ilb);
3820 }
3821 }
3822
3823 /*
3824 * If this cpu is idle and doing idle load balancing for all the
3825 * cpus with ticks stopped, is it time for that to stop?
3826 */
3827 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
3828 cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3829 resched_cpu(cpu);
3830 return;
3831 }
3832
3833 /*
3834 * If this cpu is idle and the idle load balancing is done by
3835 * someone else, then no need raise the SCHED_SOFTIRQ
3836 */
3837 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
3838 cpu_isset(cpu, nohz.cpu_mask))
3839 return;
3840#endif
3841 if (time_after_eq(jiffies, rq->next_balance))
3842 raise_softirq(SCHED_SOFTIRQ);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003843}
Ingo Molnardd41f592007-07-09 18:51:59 +02003844
3845#else /* CONFIG_SMP */
3846
Linus Torvalds1da177e2005-04-16 15:20:36 -07003847/*
3848 * on UP we do not need to balance between CPUs:
3849 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003850static inline void idle_balance(int cpu, struct rq *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003851{
3852}
Ingo Molnardd41f592007-07-09 18:51:59 +02003853
Linus Torvalds1da177e2005-04-16 15:20:36 -07003854#endif
3855
Linus Torvalds1da177e2005-04-16 15:20:36 -07003856DEFINE_PER_CPU(struct kernel_stat, kstat);
3857
3858EXPORT_PER_CPU_SYMBOL(kstat);
3859
3860/*
Ingo Molnar41b86e92007-07-09 18:51:58 +02003861 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3862 * that have not yet been banked in case the task is currently running.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003863 */
Ingo Molnar41b86e92007-07-09 18:51:58 +02003864unsigned long long task_sched_runtime(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003865{
Linus Torvalds1da177e2005-04-16 15:20:36 -07003866 unsigned long flags;
Ingo Molnar41b86e92007-07-09 18:51:58 +02003867 u64 ns, delta_exec;
3868 struct rq *rq;
Ingo Molnar48f24c42006-07-03 00:25:40 -07003869
Ingo Molnar41b86e92007-07-09 18:51:58 +02003870 rq = task_rq_lock(p, &flags);
3871 ns = p->se.sum_exec_runtime;
Dmitry Adamushko051a1d12007-12-18 15:21:13 +01003872 if (task_current(rq, p)) {
Ingo Molnara8e504d2007-08-09 11:16:47 +02003873 update_rq_clock(rq);
3874 delta_exec = rq->clock - p->se.exec_start;
Ingo Molnar41b86e92007-07-09 18:51:58 +02003875 if ((s64)delta_exec > 0)
3876 ns += delta_exec;
3877 }
3878 task_rq_unlock(rq, &flags);
Ingo Molnar48f24c42006-07-03 00:25:40 -07003879
Linus Torvalds1da177e2005-04-16 15:20:36 -07003880 return ns;
3881}
3882
3883/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003884 * Account user cpu time to a process.
3885 * @p: the process that the cpu time gets accounted to
Linus Torvalds1da177e2005-04-16 15:20:36 -07003886 * @cputime: the cpu time spent in user space since the last update
3887 */
3888void account_user_time(struct task_struct *p, cputime_t cputime)
3889{
3890 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3891 cputime64_t tmp;
3892
3893 p->utime = cputime_add(p->utime, cputime);
3894
3895 /* Add user time to cpustat. */
3896 tmp = cputime_to_cputime64(cputime);
3897 if (TASK_NICE(p) > 0)
3898 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3899 else
3900 cpustat->user = cputime64_add(cpustat->user, tmp);
3901}
3902
3903/*
Laurent Vivier94886b82007-10-15 17:00:19 +02003904 * Account guest cpu time to a process.
3905 * @p: the process that the cpu time gets accounted to
3906 * @cputime: the cpu time spent in virtual machine since the last update
3907 */
Adrian Bunkf7402e02007-10-29 21:18:10 +01003908static void account_guest_time(struct task_struct *p, cputime_t cputime)
Laurent Vivier94886b82007-10-15 17:00:19 +02003909{
3910 cputime64_t tmp;
3911 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3912
3913 tmp = cputime_to_cputime64(cputime);
3914
3915 p->utime = cputime_add(p->utime, cputime);
3916 p->gtime = cputime_add(p->gtime, cputime);
3917
3918 cpustat->user = cputime64_add(cpustat->user, tmp);
3919 cpustat->guest = cputime64_add(cpustat->guest, tmp);
3920}
3921
3922/*
Michael Neulingc66f08b2007-10-18 03:06:34 -07003923 * Account scaled user cpu time to a process.
3924 * @p: the process that the cpu time gets accounted to
3925 * @cputime: the cpu time spent in user space since the last update
3926 */
3927void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
3928{
3929 p->utimescaled = cputime_add(p->utimescaled, cputime);
3930}
3931
3932/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003933 * Account system cpu time to a process.
3934 * @p: the process that the cpu time gets accounted to
3935 * @hardirq_offset: the offset to subtract from hardirq_count()
3936 * @cputime: the cpu time spent in kernel space since the last update
3937 */
3938void account_system_time(struct task_struct *p, int hardirq_offset,
3939 cputime_t cputime)
3940{
3941 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003942 struct rq *rq = this_rq();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003943 cputime64_t tmp;
3944
Harvey Harrison983ed7a2008-04-24 18:17:55 -07003945 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
3946 account_guest_time(p, cputime);
3947 return;
3948 }
Laurent Vivier94886b82007-10-15 17:00:19 +02003949
Linus Torvalds1da177e2005-04-16 15:20:36 -07003950 p->stime = cputime_add(p->stime, cputime);
3951
3952 /* Add system time to cpustat. */
3953 tmp = cputime_to_cputime64(cputime);
3954 if (hardirq_count() - hardirq_offset)
3955 cpustat->irq = cputime64_add(cpustat->irq, tmp);
3956 else if (softirq_count())
3957 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
Andrew Mortoncfb52852007-11-14 16:59:45 -08003958 else if (p != rq->idle)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003959 cpustat->system = cputime64_add(cpustat->system, tmp);
Andrew Mortoncfb52852007-11-14 16:59:45 -08003960 else if (atomic_read(&rq->nr_iowait) > 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003961 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
3962 else
3963 cpustat->idle = cputime64_add(cpustat->idle, tmp);
3964 /* Account for system time used */
3965 acct_update_integrals(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003966}
3967
3968/*
Michael Neulingc66f08b2007-10-18 03:06:34 -07003969 * Account scaled system cpu time to a process.
3970 * @p: the process that the cpu time gets accounted to
3971 * @hardirq_offset: the offset to subtract from hardirq_count()
3972 * @cputime: the cpu time spent in kernel space since the last update
3973 */
3974void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
3975{
3976 p->stimescaled = cputime_add(p->stimescaled, cputime);
3977}
3978
3979/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003980 * Account for involuntary wait time.
3981 * @p: the process from which the cpu time has been stolen
3982 * @steal: the cpu time spent in involuntary wait
3983 */
3984void account_steal_time(struct task_struct *p, cputime_t steal)
3985{
3986 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3987 cputime64_t tmp = cputime_to_cputime64(steal);
Ingo Molnar70b97a72006-07-03 00:25:42 -07003988 struct rq *rq = this_rq();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003989
3990 if (p == rq->idle) {
3991 p->stime = cputime_add(p->stime, steal);
3992 if (atomic_read(&rq->nr_iowait) > 0)
3993 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
3994 else
3995 cpustat->idle = cputime64_add(cpustat->idle, tmp);
Andrew Mortoncfb52852007-11-14 16:59:45 -08003996 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07003997 cpustat->steal = cputime64_add(cpustat->steal, tmp);
3998}
3999
Christoph Lameter7835b982006-12-10 02:20:22 -08004000/*
4001 * This function gets called by the timer code, with HZ frequency.
4002 * We call it with interrupts disabled.
4003 *
4004 * It also gets called by the fork code, when changing the parent's
4005 * timeslices.
4006 */
4007void scheduler_tick(void)
4008{
Christoph Lameter7835b982006-12-10 02:20:22 -08004009 int cpu = smp_processor_id();
4010 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02004011 struct task_struct *curr = rq->curr;
Peter Zijlstra3e51f332008-05-03 18:29:28 +02004012
4013 sched_clock_tick();
Christoph Lameter7835b982006-12-10 02:20:22 -08004014
Ingo Molnardd41f592007-07-09 18:51:59 +02004015 spin_lock(&rq->lock);
Peter Zijlstra3e51f332008-05-03 18:29:28 +02004016 update_rq_clock(rq);
Ingo Molnarf1a438d2007-08-09 11:16:45 +02004017 update_cpu_load(rq);
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01004018 curr->sched_class->task_tick(rq, curr, 0);
Ingo Molnardd41f592007-07-09 18:51:59 +02004019 spin_unlock(&rq->lock);
4020
Christoph Lametere418e1c2006-12-10 02:20:23 -08004021#ifdef CONFIG_SMP
Ingo Molnardd41f592007-07-09 18:51:59 +02004022 rq->idle_at_tick = idle_cpu(cpu);
4023 trigger_load_balance(rq, cpu);
Christoph Lametere418e1c2006-12-10 02:20:23 -08004024#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07004025}
4026
Linus Torvalds1da177e2005-04-16 15:20:36 -07004027#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
4028
Srinivasa Ds43627582008-02-23 15:24:04 -08004029void __kprobes add_preempt_count(int val)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004030{
4031 /*
4032 * Underflow?
4033 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07004034 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
4035 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004036 preempt_count() += val;
4037 /*
4038 * Spinlock count overflowing soon?
4039 */
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08004040 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
4041 PREEMPT_MASK - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004042}
4043EXPORT_SYMBOL(add_preempt_count);
4044
Srinivasa Ds43627582008-02-23 15:24:04 -08004045void __kprobes sub_preempt_count(int val)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004046{
4047 /*
4048 * Underflow?
4049 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07004050 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
4051 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004052 /*
4053 * Is the spinlock portion underflowing?
4054 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07004055 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
4056 !(preempt_count() & PREEMPT_MASK)))
4057 return;
4058
Linus Torvalds1da177e2005-04-16 15:20:36 -07004059 preempt_count() -= val;
4060}
4061EXPORT_SYMBOL(sub_preempt_count);
4062
4063#endif
4064
4065/*
Ingo Molnardd41f592007-07-09 18:51:59 +02004066 * Print scheduling while atomic bug:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004067 */
Ingo Molnardd41f592007-07-09 18:51:59 +02004068static noinline void __schedule_bug(struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004069{
Satyam Sharma838225b2007-10-24 18:23:50 +02004070 struct pt_regs *regs = get_irq_regs();
4071
4072 printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n",
4073 prev->comm, prev->pid, preempt_count());
4074
Ingo Molnardd41f592007-07-09 18:51:59 +02004075 debug_show_held_locks(prev);
Arjan van de Vene21f5b12008-05-23 09:05:58 -07004076 print_modules();
Ingo Molnardd41f592007-07-09 18:51:59 +02004077 if (irqs_disabled())
4078 print_irqtrace_events(prev);
Satyam Sharma838225b2007-10-24 18:23:50 +02004079
4080 if (regs)
4081 show_regs(regs);
4082 else
4083 dump_stack();
Ingo Molnardd41f592007-07-09 18:51:59 +02004084}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004085
Ingo Molnardd41f592007-07-09 18:51:59 +02004086/*
4087 * Various schedule()-time debugging checks and statistics:
4088 */
4089static inline void schedule_debug(struct task_struct *prev)
4090{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004091 /*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004092 * Test if we are atomic. Since do_exit() needs to call into
Linus Torvalds1da177e2005-04-16 15:20:36 -07004093 * schedule() atomically, we ignore that path for now.
4094 * Otherwise, whine if we are scheduling when we should not be.
4095 */
Roel Kluin3f33a7c2008-05-13 23:44:11 +02004096 if (unlikely(in_atomic_preempt_off() && !prev->exit_state))
Ingo Molnardd41f592007-07-09 18:51:59 +02004097 __schedule_bug(prev);
4098
Linus Torvalds1da177e2005-04-16 15:20:36 -07004099 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
4100
Ingo Molnar2d723762007-10-15 17:00:12 +02004101 schedstat_inc(this_rq(), sched_count);
Ingo Molnarb8efb562007-10-15 17:00:10 +02004102#ifdef CONFIG_SCHEDSTATS
4103 if (unlikely(prev->lock_depth >= 0)) {
Ingo Molnar2d723762007-10-15 17:00:12 +02004104 schedstat_inc(this_rq(), bkl_count);
4105 schedstat_inc(prev, sched_info.bkl_count);
Ingo Molnarb8efb562007-10-15 17:00:10 +02004106 }
4107#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02004108}
4109
4110/*
4111 * Pick up the highest-prio task:
4112 */
4113static inline struct task_struct *
Ingo Molnarff95f3d2007-08-09 11:16:49 +02004114pick_next_task(struct rq *rq, struct task_struct *prev)
Ingo Molnardd41f592007-07-09 18:51:59 +02004115{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02004116 const struct sched_class *class;
Ingo Molnardd41f592007-07-09 18:51:59 +02004117 struct task_struct *p;
4118
4119 /*
4120 * Optimization: we know that if all tasks are in
4121 * the fair class we can call that function directly:
4122 */
4123 if (likely(rq->nr_running == rq->cfs.nr_running)) {
Ingo Molnarfb8d4722007-08-09 11:16:48 +02004124 p = fair_sched_class.pick_next_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004125 if (likely(p))
4126 return p;
4127 }
4128
4129 class = sched_class_highest;
4130 for ( ; ; ) {
Ingo Molnarfb8d4722007-08-09 11:16:48 +02004131 p = class->pick_next_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004132 if (p)
4133 return p;
4134 /*
4135 * Will never be NULL as the idle class always
4136 * returns a non-NULL p:
4137 */
4138 class = class->next;
4139 }
4140}
4141
4142/*
4143 * schedule() is the main scheduler function.
4144 */
4145asmlinkage void __sched schedule(void)
4146{
4147 struct task_struct *prev, *next;
Harvey Harrison67ca7bd2008-02-15 09:56:36 -08004148 unsigned long *switch_count;
Ingo Molnardd41f592007-07-09 18:51:59 +02004149 struct rq *rq;
Mike Galbraithf333fdc2008-05-12 21:20:55 +02004150 int cpu, hrtick = sched_feat(HRTICK);
Ingo Molnardd41f592007-07-09 18:51:59 +02004151
Linus Torvalds1da177e2005-04-16 15:20:36 -07004152need_resched:
4153 preempt_disable();
Ingo Molnardd41f592007-07-09 18:51:59 +02004154 cpu = smp_processor_id();
4155 rq = cpu_rq(cpu);
4156 rcu_qsctr_inc(cpu);
4157 prev = rq->curr;
4158 switch_count = &prev->nivcsw;
4159
Linus Torvalds1da177e2005-04-16 15:20:36 -07004160 release_kernel_lock(prev);
4161need_resched_nonpreemptible:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004162
Ingo Molnardd41f592007-07-09 18:51:59 +02004163 schedule_debug(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004164
Mike Galbraithf333fdc2008-05-12 21:20:55 +02004165 if (hrtick)
4166 hrtick_clear(rq);
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01004167
Ingo Molnar1e819952007-10-15 17:00:13 +02004168 /*
4169 * Do the rq-clock update outside the rq lock:
4170 */
4171 local_irq_disable();
Peter Zijlstra3e51f332008-05-03 18:29:28 +02004172 update_rq_clock(rq);
Ingo Molnar1e819952007-10-15 17:00:13 +02004173 spin_lock(&rq->lock);
4174 clear_tsk_need_resched(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004175
Ingo Molnardd41f592007-07-09 18:51:59 +02004176 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
Oleg Nesterov16882c12008-06-08 21:20:41 +04004177 if (unlikely(signal_pending_state(prev->state, prev)))
Ingo Molnardd41f592007-07-09 18:51:59 +02004178 prev->state = TASK_RUNNING;
Oleg Nesterov16882c12008-06-08 21:20:41 +04004179 else
Ingo Molnar2e1cb742007-08-09 11:16:49 +02004180 deactivate_task(rq, prev, 1);
Ingo Molnardd41f592007-07-09 18:51:59 +02004181 switch_count = &prev->nvcsw;
4182 }
4183
Steven Rostedt9a897c52008-01-25 21:08:22 +01004184#ifdef CONFIG_SMP
4185 if (prev->sched_class->pre_schedule)
4186 prev->sched_class->pre_schedule(rq, prev);
4187#endif
Steven Rostedtf65eda42008-01-25 21:08:07 +01004188
Ingo Molnardd41f592007-07-09 18:51:59 +02004189 if (unlikely(!rq->nr_running))
4190 idle_balance(cpu, rq);
4191
Ingo Molnar31ee5292007-08-09 11:16:49 +02004192 prev->sched_class->put_prev_task(rq, prev);
Ingo Molnarff95f3d2007-08-09 11:16:49 +02004193 next = pick_next_task(rq, prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004194
Linus Torvalds1da177e2005-04-16 15:20:36 -07004195 if (likely(prev != next)) {
David Simner673a90a2008-04-29 10:08:59 +01004196 sched_info_switch(prev, next);
4197
Linus Torvalds1da177e2005-04-16 15:20:36 -07004198 rq->nr_switches++;
4199 rq->curr = next;
4200 ++*switch_count;
4201
Ingo Molnardd41f592007-07-09 18:51:59 +02004202 context_switch(rq, prev, next); /* unlocks the rq */
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01004203 /*
4204 * the context switch might have flipped the stack from under
4205 * us, hence refresh the local variables.
4206 */
4207 cpu = smp_processor_id();
4208 rq = cpu_rq(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004209 } else
4210 spin_unlock_irq(&rq->lock);
4211
Mike Galbraithf333fdc2008-05-12 21:20:55 +02004212 if (hrtick)
4213 hrtick_set(rq);
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01004214
4215 if (unlikely(reacquire_kernel_lock(current) < 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004216 goto need_resched_nonpreemptible;
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01004217
Linus Torvalds1da177e2005-04-16 15:20:36 -07004218 preempt_enable_no_resched();
4219 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
4220 goto need_resched;
4221}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004222EXPORT_SYMBOL(schedule);
4223
4224#ifdef CONFIG_PREEMPT
4225/*
Andreas Mohr2ed6e342006-07-10 04:43:52 -07004226 * this is the entry point to schedule() from in-kernel preemption
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004227 * off of preempt_enable. Kernel preemptions off return from interrupt
Linus Torvalds1da177e2005-04-16 15:20:36 -07004228 * occur there and call schedule directly.
4229 */
4230asmlinkage void __sched preempt_schedule(void)
4231{
4232 struct thread_info *ti = current_thread_info();
Ingo Molnar6478d882008-01-25 21:08:33 +01004233
Linus Torvalds1da177e2005-04-16 15:20:36 -07004234 /*
4235 * If there is a non-zero preempt_count or interrupts are disabled,
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004236 * we do not want to preempt the current task. Just return..
Linus Torvalds1da177e2005-04-16 15:20:36 -07004237 */
Nick Pigginbeed33a2006-10-11 01:21:52 -07004238 if (likely(ti->preempt_count || irqs_disabled()))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004239 return;
4240
Andi Kleen3a5c3592007-10-15 17:00:14 +02004241 do {
4242 add_preempt_count(PREEMPT_ACTIVE);
Andi Kleen3a5c3592007-10-15 17:00:14 +02004243 schedule();
Andi Kleen3a5c3592007-10-15 17:00:14 +02004244 sub_preempt_count(PREEMPT_ACTIVE);
4245
4246 /*
4247 * Check again in case we missed a preemption opportunity
4248 * between schedule and now.
4249 */
4250 barrier();
4251 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07004252}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004253EXPORT_SYMBOL(preempt_schedule);
4254
4255/*
Andreas Mohr2ed6e342006-07-10 04:43:52 -07004256 * this is the entry point to schedule() from kernel preemption
Linus Torvalds1da177e2005-04-16 15:20:36 -07004257 * off of irq context.
4258 * Note, that this is called and return with irqs disabled. This will
4259 * protect us against recursive calling from irq.
4260 */
4261asmlinkage void __sched preempt_schedule_irq(void)
4262{
4263 struct thread_info *ti = current_thread_info();
Ingo Molnar6478d882008-01-25 21:08:33 +01004264
Andreas Mohr2ed6e342006-07-10 04:43:52 -07004265 /* Catch callers which need to be fixed */
Linus Torvalds1da177e2005-04-16 15:20:36 -07004266 BUG_ON(ti->preempt_count || !irqs_disabled());
4267
Andi Kleen3a5c3592007-10-15 17:00:14 +02004268 do {
4269 add_preempt_count(PREEMPT_ACTIVE);
Andi Kleen3a5c3592007-10-15 17:00:14 +02004270 local_irq_enable();
4271 schedule();
4272 local_irq_disable();
Andi Kleen3a5c3592007-10-15 17:00:14 +02004273 sub_preempt_count(PREEMPT_ACTIVE);
4274
4275 /*
4276 * Check again in case we missed a preemption opportunity
4277 * between schedule and now.
4278 */
4279 barrier();
4280 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07004281}
4282
4283#endif /* CONFIG_PREEMPT */
4284
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004285int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
4286 void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004287{
Ingo Molnar48f24c42006-07-03 00:25:40 -07004288 return try_to_wake_up(curr->private, mode, sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004289}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004290EXPORT_SYMBOL(default_wake_function);
4291
4292/*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004293 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
4294 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
Linus Torvalds1da177e2005-04-16 15:20:36 -07004295 * number) then we wake all the non-exclusive tasks and one exclusive task.
4296 *
4297 * There are circumstances in which we can try to wake a task which has already
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004298 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
Linus Torvalds1da177e2005-04-16 15:20:36 -07004299 * zero in this (rare) case, and we handle it by continuing to scan the queue.
4300 */
4301static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
4302 int nr_exclusive, int sync, void *key)
4303{
Matthias Kaehlcke2e458742007-10-15 17:00:02 +02004304 wait_queue_t *curr, *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004305
Matthias Kaehlcke2e458742007-10-15 17:00:02 +02004306 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
Ingo Molnar48f24c42006-07-03 00:25:40 -07004307 unsigned flags = curr->flags;
4308
Linus Torvalds1da177e2005-04-16 15:20:36 -07004309 if (curr->func(curr, mode, sync, key) &&
Ingo Molnar48f24c42006-07-03 00:25:40 -07004310 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004311 break;
4312 }
4313}
4314
4315/**
4316 * __wake_up - wake up threads blocked on a waitqueue.
4317 * @q: the waitqueue
4318 * @mode: which threads
4319 * @nr_exclusive: how many wake-one or wake-many threads to wake up
Martin Waitz67be2dd2005-05-01 08:59:26 -07004320 * @key: is directly passed to the wakeup function
Linus Torvalds1da177e2005-04-16 15:20:36 -07004321 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08004322void __wake_up(wait_queue_head_t *q, unsigned int mode,
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004323 int nr_exclusive, void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004324{
4325 unsigned long flags;
4326
4327 spin_lock_irqsave(&q->lock, flags);
4328 __wake_up_common(q, mode, nr_exclusive, 0, key);
4329 spin_unlock_irqrestore(&q->lock, flags);
4330}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004331EXPORT_SYMBOL(__wake_up);
4332
4333/*
4334 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
4335 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08004336void __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004337{
4338 __wake_up_common(q, mode, 1, 0, NULL);
4339}
4340
4341/**
Martin Waitz67be2dd2005-05-01 08:59:26 -07004342 * __wake_up_sync - wake up threads blocked on a waitqueue.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004343 * @q: the waitqueue
4344 * @mode: which threads
4345 * @nr_exclusive: how many wake-one or wake-many threads to wake up
4346 *
4347 * The sync wakeup differs that the waker knows that it will schedule
4348 * away soon, so while the target thread will be woken up, it will not
4349 * be migrated to another CPU - ie. the two threads are 'synchronized'
4350 * with each other. This can prevent needless bouncing between CPUs.
4351 *
4352 * On UP it can prevent extra preemption.
4353 */
Harvey Harrison7ad5b3a2008-02-08 04:19:53 -08004354void
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004355__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004356{
4357 unsigned long flags;
4358 int sync = 1;
4359
4360 if (unlikely(!q))
4361 return;
4362
4363 if (unlikely(!nr_exclusive))
4364 sync = 0;
4365
4366 spin_lock_irqsave(&q->lock, flags);
4367 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
4368 spin_unlock_irqrestore(&q->lock, flags);
4369}
4370EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
4371
Ingo Molnarb15136e2007-10-24 18:23:48 +02004372void complete(struct completion *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004373{
4374 unsigned long flags;
4375
4376 spin_lock_irqsave(&x->wait.lock, flags);
4377 x->done++;
Matthew Wilcoxd9514f62007-12-06 11:07:07 -05004378 __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004379 spin_unlock_irqrestore(&x->wait.lock, flags);
4380}
4381EXPORT_SYMBOL(complete);
4382
Ingo Molnarb15136e2007-10-24 18:23:48 +02004383void complete_all(struct completion *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004384{
4385 unsigned long flags;
4386
4387 spin_lock_irqsave(&x->wait.lock, flags);
4388 x->done += UINT_MAX/2;
Matthew Wilcoxd9514f62007-12-06 11:07:07 -05004389 __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004390 spin_unlock_irqrestore(&x->wait.lock, flags);
4391}
4392EXPORT_SYMBOL(complete_all);
4393
Andi Kleen8cbbe862007-10-15 17:00:14 +02004394static inline long __sched
4395do_wait_for_common(struct completion *x, long timeout, int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004396{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004397 if (!x->done) {
4398 DECLARE_WAITQUEUE(wait, current);
4399
4400 wait.flags |= WQ_FLAG_EXCLUSIVE;
4401 __add_wait_queue_tail(&x->wait, &wait);
4402 do {
Matthew Wilcox009e5772007-12-06 12:29:54 -05004403 if ((state == TASK_INTERRUPTIBLE &&
4404 signal_pending(current)) ||
4405 (state == TASK_KILLABLE &&
4406 fatal_signal_pending(current))) {
Andi Kleen8cbbe862007-10-15 17:00:14 +02004407 __remove_wait_queue(&x->wait, &wait);
4408 return -ERESTARTSYS;
4409 }
4410 __set_current_state(state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004411 spin_unlock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02004412 timeout = schedule_timeout(timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004413 spin_lock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02004414 if (!timeout) {
4415 __remove_wait_queue(&x->wait, &wait);
4416 return timeout;
4417 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004418 } while (!x->done);
4419 __remove_wait_queue(&x->wait, &wait);
4420 }
4421 x->done--;
Andi Kleen8cbbe862007-10-15 17:00:14 +02004422 return timeout;
4423}
4424
4425static long __sched
4426wait_for_common(struct completion *x, long timeout, int state)
4427{
4428 might_sleep();
4429
4430 spin_lock_irq(&x->wait.lock);
4431 timeout = do_wait_for_common(x, timeout, state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004432 spin_unlock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02004433 return timeout;
4434}
4435
Ingo Molnarb15136e2007-10-24 18:23:48 +02004436void __sched wait_for_completion(struct completion *x)
Andi Kleen8cbbe862007-10-15 17:00:14 +02004437{
4438 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004439}
4440EXPORT_SYMBOL(wait_for_completion);
4441
Ingo Molnarb15136e2007-10-24 18:23:48 +02004442unsigned long __sched
Linus Torvalds1da177e2005-04-16 15:20:36 -07004443wait_for_completion_timeout(struct completion *x, unsigned long timeout)
4444{
Andi Kleen8cbbe862007-10-15 17:00:14 +02004445 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004446}
4447EXPORT_SYMBOL(wait_for_completion_timeout);
4448
Andi Kleen8cbbe862007-10-15 17:00:14 +02004449int __sched wait_for_completion_interruptible(struct completion *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004450{
Andi Kleen51e97992007-10-18 21:32:55 +02004451 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
4452 if (t == -ERESTARTSYS)
4453 return t;
4454 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004455}
4456EXPORT_SYMBOL(wait_for_completion_interruptible);
4457
Ingo Molnarb15136e2007-10-24 18:23:48 +02004458unsigned long __sched
Linus Torvalds1da177e2005-04-16 15:20:36 -07004459wait_for_completion_interruptible_timeout(struct completion *x,
4460 unsigned long timeout)
4461{
Andi Kleen8cbbe862007-10-15 17:00:14 +02004462 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004463}
4464EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
4465
Matthew Wilcox009e5772007-12-06 12:29:54 -05004466int __sched wait_for_completion_killable(struct completion *x)
4467{
4468 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
4469 if (t == -ERESTARTSYS)
4470 return t;
4471 return 0;
4472}
4473EXPORT_SYMBOL(wait_for_completion_killable);
4474
Andi Kleen8cbbe862007-10-15 17:00:14 +02004475static long __sched
4476sleep_on_common(wait_queue_head_t *q, int state, long timeout)
Ingo Molnar0fec1712007-07-09 18:52:01 +02004477{
4478 unsigned long flags;
4479 wait_queue_t wait;
4480
4481 init_waitqueue_entry(&wait, current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004482
Andi Kleen8cbbe862007-10-15 17:00:14 +02004483 __set_current_state(state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004484
Andi Kleen8cbbe862007-10-15 17:00:14 +02004485 spin_lock_irqsave(&q->lock, flags);
4486 __add_wait_queue(q, &wait);
4487 spin_unlock(&q->lock);
4488 timeout = schedule_timeout(timeout);
4489 spin_lock_irq(&q->lock);
4490 __remove_wait_queue(q, &wait);
4491 spin_unlock_irqrestore(&q->lock, flags);
4492
4493 return timeout;
4494}
4495
4496void __sched interruptible_sleep_on(wait_queue_head_t *q)
4497{
4498 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004499}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004500EXPORT_SYMBOL(interruptible_sleep_on);
4501
Ingo Molnar0fec1712007-07-09 18:52:01 +02004502long __sched
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004503interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004504{
Andi Kleen8cbbe862007-10-15 17:00:14 +02004505 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004506}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004507EXPORT_SYMBOL(interruptible_sleep_on_timeout);
4508
Ingo Molnar0fec1712007-07-09 18:52:01 +02004509void __sched sleep_on(wait_queue_head_t *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004510{
Andi Kleen8cbbe862007-10-15 17:00:14 +02004511 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004512}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004513EXPORT_SYMBOL(sleep_on);
4514
Ingo Molnar0fec1712007-07-09 18:52:01 +02004515long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004516{
Andi Kleen8cbbe862007-10-15 17:00:14 +02004517 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004518}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004519EXPORT_SYMBOL(sleep_on_timeout);
4520
Ingo Molnarb29739f2006-06-27 02:54:51 -07004521#ifdef CONFIG_RT_MUTEXES
4522
4523/*
4524 * rt_mutex_setprio - set the current priority of a task
4525 * @p: task
4526 * @prio: prio value (kernel-internal form)
4527 *
4528 * This function changes the 'effective' priority of a task. It does
4529 * not touch ->normal_prio like __setscheduler().
4530 *
4531 * Used by the rt_mutex code to implement priority inheritance logic.
4532 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004533void rt_mutex_setprio(struct task_struct *p, int prio)
Ingo Molnarb29739f2006-06-27 02:54:51 -07004534{
4535 unsigned long flags;
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004536 int oldprio, on_rq, running;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004537 struct rq *rq;
Steven Rostedtcb469842008-01-25 21:08:22 +01004538 const struct sched_class *prev_class = p->sched_class;
Ingo Molnarb29739f2006-06-27 02:54:51 -07004539
4540 BUG_ON(prio < 0 || prio > MAX_PRIO);
4541
4542 rq = task_rq_lock(p, &flags);
Ingo Molnara8e504d2007-08-09 11:16:47 +02004543 update_rq_clock(rq);
Ingo Molnarb29739f2006-06-27 02:54:51 -07004544
Andrew Mortond5f9f942007-05-08 20:27:06 -07004545 oldprio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02004546 on_rq = p->se.on_rq;
Dmitry Adamushko051a1d12007-12-18 15:21:13 +01004547 running = task_current(rq, p);
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004548 if (on_rq)
Ingo Molnar69be72c2007-08-09 11:16:49 +02004549 dequeue_task(rq, p, 0);
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004550 if (running)
4551 p->sched_class->put_prev_task(rq, p);
Ingo Molnardd41f592007-07-09 18:51:59 +02004552
4553 if (rt_prio(prio))
4554 p->sched_class = &rt_sched_class;
4555 else
4556 p->sched_class = &fair_sched_class;
4557
Ingo Molnarb29739f2006-06-27 02:54:51 -07004558 p->prio = prio;
4559
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004560 if (running)
4561 p->sched_class->set_curr_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004562 if (on_rq) {
Ingo Molnar8159f872007-08-09 11:16:49 +02004563 enqueue_task(rq, p, 0);
Steven Rostedtcb469842008-01-25 21:08:22 +01004564
4565 check_class_changed(rq, p, prev_class, oldprio, running);
Ingo Molnarb29739f2006-06-27 02:54:51 -07004566 }
4567 task_rq_unlock(rq, &flags);
4568}
4569
4570#endif
4571
Ingo Molnar36c8b582006-07-03 00:25:41 -07004572void set_user_nice(struct task_struct *p, long nice)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004573{
Ingo Molnardd41f592007-07-09 18:51:59 +02004574 int old_prio, delta, on_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004575 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004576 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004577
4578 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4579 return;
4580 /*
4581 * We have to be careful, if called from sys_setpriority(),
4582 * the task might be in the middle of scheduling on another CPU.
4583 */
4584 rq = task_rq_lock(p, &flags);
Ingo Molnara8e504d2007-08-09 11:16:47 +02004585 update_rq_clock(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004586 /*
4587 * The RT priorities are set via sched_setscheduler(), but we still
4588 * allow the 'normal' nice value to be set - but as expected
4589 * it wont have any effect on scheduling until the task is
Ingo Molnardd41f592007-07-09 18:51:59 +02004590 * SCHED_FIFO/SCHED_RR:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004591 */
Ingo Molnare05606d2007-07-09 18:51:59 +02004592 if (task_has_rt_policy(p)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07004593 p->static_prio = NICE_TO_PRIO(nice);
4594 goto out_unlock;
4595 }
Ingo Molnardd41f592007-07-09 18:51:59 +02004596 on_rq = p->se.on_rq;
Ingo Molnar6363ca52008-05-29 11:28:57 +02004597 if (on_rq) {
Ingo Molnar69be72c2007-08-09 11:16:49 +02004598 dequeue_task(rq, p, 0);
Ingo Molnar6363ca52008-05-29 11:28:57 +02004599 dec_load(rq, p);
4600 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004601
Linus Torvalds1da177e2005-04-16 15:20:36 -07004602 p->static_prio = NICE_TO_PRIO(nice);
Peter Williams2dd73a42006-06-27 02:54:34 -07004603 set_load_weight(p);
Ingo Molnarb29739f2006-06-27 02:54:51 -07004604 old_prio = p->prio;
4605 p->prio = effective_prio(p);
4606 delta = p->prio - old_prio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004607
Ingo Molnardd41f592007-07-09 18:51:59 +02004608 if (on_rq) {
Ingo Molnar8159f872007-08-09 11:16:49 +02004609 enqueue_task(rq, p, 0);
Ingo Molnar6363ca52008-05-29 11:28:57 +02004610 inc_load(rq, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004611 /*
Andrew Mortond5f9f942007-05-08 20:27:06 -07004612 * If the task increased its priority or is running and
4613 * lowered its priority, then reschedule its CPU:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004614 */
Andrew Mortond5f9f942007-05-08 20:27:06 -07004615 if (delta < 0 || (delta > 0 && task_running(rq, p)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004616 resched_task(rq->curr);
4617 }
4618out_unlock:
4619 task_rq_unlock(rq, &flags);
4620}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004621EXPORT_SYMBOL(set_user_nice);
4622
Matt Mackalle43379f2005-05-01 08:59:00 -07004623/*
4624 * can_nice - check if a task can reduce its nice value
4625 * @p: task
4626 * @nice: nice value
4627 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004628int can_nice(const struct task_struct *p, const int nice)
Matt Mackalle43379f2005-05-01 08:59:00 -07004629{
Matt Mackall024f4742005-08-18 11:24:19 -07004630 /* convert nice value [19,-20] to rlimit style value [1,40] */
4631 int nice_rlim = 20 - nice;
Ingo Molnar48f24c42006-07-03 00:25:40 -07004632
Matt Mackalle43379f2005-05-01 08:59:00 -07004633 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
4634 capable(CAP_SYS_NICE));
4635}
4636
Linus Torvalds1da177e2005-04-16 15:20:36 -07004637#ifdef __ARCH_WANT_SYS_NICE
4638
4639/*
4640 * sys_nice - change the priority of the current process.
4641 * @increment: priority increment
4642 *
4643 * sys_setpriority is a more generic, but much slower function that
4644 * does similar things.
4645 */
4646asmlinkage long sys_nice(int increment)
4647{
Ingo Molnar48f24c42006-07-03 00:25:40 -07004648 long nice, retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004649
4650 /*
4651 * Setpriority might change our priority at the same moment.
4652 * We don't have to worry. Conceptually one call occurs first
4653 * and we have a single winner.
4654 */
Matt Mackalle43379f2005-05-01 08:59:00 -07004655 if (increment < -40)
4656 increment = -40;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004657 if (increment > 40)
4658 increment = 40;
4659
4660 nice = PRIO_TO_NICE(current->static_prio) + increment;
4661 if (nice < -20)
4662 nice = -20;
4663 if (nice > 19)
4664 nice = 19;
4665
Matt Mackalle43379f2005-05-01 08:59:00 -07004666 if (increment < 0 && !can_nice(current, nice))
4667 return -EPERM;
4668
Linus Torvalds1da177e2005-04-16 15:20:36 -07004669 retval = security_task_setnice(current, nice);
4670 if (retval)
4671 return retval;
4672
4673 set_user_nice(current, nice);
4674 return 0;
4675}
4676
4677#endif
4678
4679/**
4680 * task_prio - return the priority value of a given task.
4681 * @p: the task in question.
4682 *
4683 * This is the priority value as seen by users in /proc.
4684 * RT tasks are offset by -200. Normal tasks are centered
4685 * around 0, value goes from -16 to +15.
4686 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004687int task_prio(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004688{
4689 return p->prio - MAX_RT_PRIO;
4690}
4691
4692/**
4693 * task_nice - return the nice value of a given task.
4694 * @p: the task in question.
4695 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004696int task_nice(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004697{
4698 return TASK_NICE(p);
4699}
Pavel Roskin150d8be2008-03-05 16:56:37 -05004700EXPORT_SYMBOL(task_nice);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004701
4702/**
4703 * idle_cpu - is a given cpu idle currently?
4704 * @cpu: the processor in question.
4705 */
4706int idle_cpu(int cpu)
4707{
4708 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
4709}
4710
Linus Torvalds1da177e2005-04-16 15:20:36 -07004711/**
4712 * idle_task - return the idle task for a given cpu.
4713 * @cpu: the processor in question.
4714 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004715struct task_struct *idle_task(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004716{
4717 return cpu_rq(cpu)->idle;
4718}
4719
4720/**
4721 * find_process_by_pid - find a process with a matching PID value.
4722 * @pid: the pid in question.
4723 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02004724static struct task_struct *find_process_by_pid(pid_t pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004725{
Pavel Emelyanov228ebcb2007-10-18 23:40:16 -07004726 return pid ? find_task_by_vpid(pid) : current;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004727}
4728
4729/* Actually do priority change: must hold rq lock. */
Ingo Molnardd41f592007-07-09 18:51:59 +02004730static void
4731__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004732{
Ingo Molnardd41f592007-07-09 18:51:59 +02004733 BUG_ON(p->se.on_rq);
Ingo Molnar48f24c42006-07-03 00:25:40 -07004734
Linus Torvalds1da177e2005-04-16 15:20:36 -07004735 p->policy = policy;
Ingo Molnardd41f592007-07-09 18:51:59 +02004736 switch (p->policy) {
4737 case SCHED_NORMAL:
4738 case SCHED_BATCH:
4739 case SCHED_IDLE:
4740 p->sched_class = &fair_sched_class;
4741 break;
4742 case SCHED_FIFO:
4743 case SCHED_RR:
4744 p->sched_class = &rt_sched_class;
4745 break;
4746 }
4747
Linus Torvalds1da177e2005-04-16 15:20:36 -07004748 p->rt_priority = prio;
Ingo Molnarb29739f2006-06-27 02:54:51 -07004749 p->normal_prio = normal_prio(p);
4750 /* we are holding p->pi_lock already */
4751 p->prio = rt_mutex_getprio(p);
Peter Williams2dd73a42006-06-27 02:54:34 -07004752 set_load_weight(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004753}
4754
4755/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08004756 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004757 * @p: the task in question.
4758 * @policy: new policy.
4759 * @param: structure containing the new RT priority.
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004760 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08004761 * NOTE that the task may be already dead.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004762 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004763int sched_setscheduler(struct task_struct *p, int policy,
4764 struct sched_param *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004765{
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004766 int retval, oldprio, oldpolicy = -1, on_rq, running;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004767 unsigned long flags;
Steven Rostedtcb469842008-01-25 21:08:22 +01004768 const struct sched_class *prev_class = p->sched_class;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004769 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004770
Steven Rostedt66e53932006-06-27 02:54:44 -07004771 /* may grab non-irq protected spin_locks */
4772 BUG_ON(in_interrupt());
Linus Torvalds1da177e2005-04-16 15:20:36 -07004773recheck:
4774 /* double check policy once rq lock held */
4775 if (policy < 0)
4776 policy = oldpolicy = p->policy;
4777 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
Ingo Molnardd41f592007-07-09 18:51:59 +02004778 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4779 policy != SCHED_IDLE)
Ingo Molnarb0a94992006-01-14 13:20:41 -08004780 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004781 /*
4782 * Valid priorities for SCHED_FIFO and SCHED_RR are
Ingo Molnardd41f592007-07-09 18:51:59 +02004783 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4784 * SCHED_BATCH and SCHED_IDLE is 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004785 */
4786 if (param->sched_priority < 0 ||
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004787 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
Steven Rostedtd46523e2005-07-25 16:28:39 -04004788 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004789 return -EINVAL;
Ingo Molnare05606d2007-07-09 18:51:59 +02004790 if (rt_policy(policy) != (param->sched_priority != 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004791 return -EINVAL;
4792
Olivier Croquette37e4ab32005-06-25 14:57:32 -07004793 /*
4794 * Allow unprivileged RT tasks to decrease priority:
4795 */
4796 if (!capable(CAP_SYS_NICE)) {
Ingo Molnare05606d2007-07-09 18:51:59 +02004797 if (rt_policy(policy)) {
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004798 unsigned long rlim_rtprio;
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004799
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004800 if (!lock_task_sighand(p, &flags))
4801 return -ESRCH;
4802 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
4803 unlock_task_sighand(p, &flags);
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004804
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004805 /* can't set/change the rt policy */
4806 if (policy != p->policy && !rlim_rtprio)
4807 return -EPERM;
4808
4809 /* can't increase priority */
4810 if (param->sched_priority > p->rt_priority &&
4811 param->sched_priority > rlim_rtprio)
4812 return -EPERM;
4813 }
Ingo Molnardd41f592007-07-09 18:51:59 +02004814 /*
4815 * Like positive nice levels, dont allow tasks to
4816 * move out of SCHED_IDLE either:
4817 */
4818 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
4819 return -EPERM;
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004820
Olivier Croquette37e4ab32005-06-25 14:57:32 -07004821 /* can't change other user's priorities */
4822 if ((current->euid != p->euid) &&
4823 (current->euid != p->uid))
4824 return -EPERM;
4825 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004826
Peter Zijlstrab68aa232008-02-13 15:45:40 +01004827#ifdef CONFIG_RT_GROUP_SCHED
4828 /*
4829 * Do not allow realtime tasks into groups that have no runtime
4830 * assigned.
4831 */
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02004832 if (rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0)
Peter Zijlstrab68aa232008-02-13 15:45:40 +01004833 return -EPERM;
4834#endif
4835
Linus Torvalds1da177e2005-04-16 15:20:36 -07004836 retval = security_task_setscheduler(p, policy, param);
4837 if (retval)
4838 return retval;
4839 /*
Ingo Molnarb29739f2006-06-27 02:54:51 -07004840 * make sure no PI-waiters arrive (or leave) while we are
4841 * changing the priority of the task:
4842 */
4843 spin_lock_irqsave(&p->pi_lock, flags);
4844 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07004845 * To be able to change p->policy safely, the apropriate
4846 * runqueue lock must be held.
4847 */
Ingo Molnarb29739f2006-06-27 02:54:51 -07004848 rq = __task_rq_lock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004849 /* recheck policy now with rq lock held */
4850 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4851 policy = oldpolicy = -1;
Ingo Molnarb29739f2006-06-27 02:54:51 -07004852 __task_rq_unlock(rq);
4853 spin_unlock_irqrestore(&p->pi_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004854 goto recheck;
4855 }
Ingo Molnar2daa3572007-08-09 11:16:51 +02004856 update_rq_clock(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004857 on_rq = p->se.on_rq;
Dmitry Adamushko051a1d12007-12-18 15:21:13 +01004858 running = task_current(rq, p);
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004859 if (on_rq)
Ingo Molnar2e1cb742007-08-09 11:16:49 +02004860 deactivate_task(rq, p, 0);
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004861 if (running)
4862 p->sched_class->put_prev_task(rq, p);
Dmitry Adamushkof6b53202007-10-15 17:00:08 +02004863
Linus Torvalds1da177e2005-04-16 15:20:36 -07004864 oldprio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02004865 __setscheduler(rq, p, policy, param->sched_priority);
Dmitry Adamushkof6b53202007-10-15 17:00:08 +02004866
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07004867 if (running)
4868 p->sched_class->set_curr_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004869 if (on_rq) {
4870 activate_task(rq, p, 0);
Steven Rostedtcb469842008-01-25 21:08:22 +01004871
4872 check_class_changed(rq, p, prev_class, oldprio, running);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004873 }
Ingo Molnarb29739f2006-06-27 02:54:51 -07004874 __task_rq_unlock(rq);
4875 spin_unlock_irqrestore(&p->pi_lock, flags);
4876
Thomas Gleixner95e02ca2006-06-27 02:55:02 -07004877 rt_mutex_adjust_pi(p);
4878
Linus Torvalds1da177e2005-04-16 15:20:36 -07004879 return 0;
4880}
4881EXPORT_SYMBOL_GPL(sched_setscheduler);
4882
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004883static int
4884do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004885{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004886 struct sched_param lparam;
4887 struct task_struct *p;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004888 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004889
4890 if (!param || pid < 0)
4891 return -EINVAL;
4892 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4893 return -EFAULT;
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004894
4895 rcu_read_lock();
4896 retval = -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004897 p = find_process_by_pid(pid);
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004898 if (p != NULL)
4899 retval = sched_setscheduler(p, policy, &lparam);
4900 rcu_read_unlock();
Ingo Molnar36c8b582006-07-03 00:25:41 -07004901
Linus Torvalds1da177e2005-04-16 15:20:36 -07004902 return retval;
4903}
4904
4905/**
4906 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4907 * @pid: the pid in question.
4908 * @policy: new policy.
4909 * @param: structure containing the new RT priority.
4910 */
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01004911asmlinkage long
4912sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004913{
Jason Baronc21761f2006-01-18 17:43:03 -08004914 /* negative values for policy are not valid */
4915 if (policy < 0)
4916 return -EINVAL;
4917
Linus Torvalds1da177e2005-04-16 15:20:36 -07004918 return do_sched_setscheduler(pid, policy, param);
4919}
4920
4921/**
4922 * sys_sched_setparam - set/change the RT priority of a thread
4923 * @pid: the pid in question.
4924 * @param: structure containing the new RT priority.
4925 */
4926asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
4927{
4928 return do_sched_setscheduler(pid, -1, param);
4929}
4930
4931/**
4932 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4933 * @pid: the pid in question.
4934 */
4935asmlinkage long sys_sched_getscheduler(pid_t pid)
4936{
Ingo Molnar36c8b582006-07-03 00:25:41 -07004937 struct task_struct *p;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004938 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004939
4940 if (pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02004941 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004942
4943 retval = -ESRCH;
4944 read_lock(&tasklist_lock);
4945 p = find_process_by_pid(pid);
4946 if (p) {
4947 retval = security_task_getscheduler(p);
4948 if (!retval)
4949 retval = p->policy;
4950 }
4951 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004952 return retval;
4953}
4954
4955/**
4956 * sys_sched_getscheduler - get the RT priority of a thread
4957 * @pid: the pid in question.
4958 * @param: structure containing the RT priority.
4959 */
4960asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
4961{
4962 struct sched_param lp;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004963 struct task_struct *p;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004964 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004965
4966 if (!param || pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02004967 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004968
4969 read_lock(&tasklist_lock);
4970 p = find_process_by_pid(pid);
4971 retval = -ESRCH;
4972 if (!p)
4973 goto out_unlock;
4974
4975 retval = security_task_getscheduler(p);
4976 if (retval)
4977 goto out_unlock;
4978
4979 lp.sched_priority = p->rt_priority;
4980 read_unlock(&tasklist_lock);
4981
4982 /*
4983 * This one might sleep, we cannot do it with a spinlock held ...
4984 */
4985 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4986
Linus Torvalds1da177e2005-04-16 15:20:36 -07004987 return retval;
4988
4989out_unlock:
4990 read_unlock(&tasklist_lock);
4991 return retval;
4992}
4993
Mike Travisb53e9212008-04-04 18:11:08 -07004994long sched_setaffinity(pid_t pid, const cpumask_t *in_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004995{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004996 cpumask_t cpus_allowed;
Mike Travisb53e9212008-04-04 18:11:08 -07004997 cpumask_t new_mask = *in_mask;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004998 struct task_struct *p;
4999 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005000
Gautham R Shenoy95402b32008-01-25 21:08:02 +01005001 get_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005002 read_lock(&tasklist_lock);
5003
5004 p = find_process_by_pid(pid);
5005 if (!p) {
5006 read_unlock(&tasklist_lock);
Gautham R Shenoy95402b32008-01-25 21:08:02 +01005007 put_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005008 return -ESRCH;
5009 }
5010
5011 /*
5012 * It is not safe to call set_cpus_allowed with the
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005013 * tasklist_lock held. We will bump the task_struct's
Linus Torvalds1da177e2005-04-16 15:20:36 -07005014 * usage count and then drop tasklist_lock.
5015 */
5016 get_task_struct(p);
5017 read_unlock(&tasklist_lock);
5018
5019 retval = -EPERM;
5020 if ((current->euid != p->euid) && (current->euid != p->uid) &&
5021 !capable(CAP_SYS_NICE))
5022 goto out_unlock;
5023
David Quigleye7834f82006-06-23 02:03:59 -07005024 retval = security_task_setscheduler(p, 0, NULL);
5025 if (retval)
5026 goto out_unlock;
5027
Mike Travisf9a86fc2008-04-04 18:11:07 -07005028 cpuset_cpus_allowed(p, &cpus_allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005029 cpus_and(new_mask, new_mask, cpus_allowed);
Paul Menage8707d8b2007-10-18 23:40:22 -07005030 again:
Mike Travis7c16ec52008-04-04 18:11:11 -07005031 retval = set_cpus_allowed_ptr(p, &new_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005032
Paul Menage8707d8b2007-10-18 23:40:22 -07005033 if (!retval) {
Mike Travisf9a86fc2008-04-04 18:11:07 -07005034 cpuset_cpus_allowed(p, &cpus_allowed);
Paul Menage8707d8b2007-10-18 23:40:22 -07005035 if (!cpus_subset(new_mask, cpus_allowed)) {
5036 /*
5037 * We must have raced with a concurrent cpuset
5038 * update. Just reset the cpus_allowed to the
5039 * cpuset's cpus_allowed
5040 */
5041 new_mask = cpus_allowed;
5042 goto again;
5043 }
5044 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07005045out_unlock:
5046 put_task_struct(p);
Gautham R Shenoy95402b32008-01-25 21:08:02 +01005047 put_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005048 return retval;
5049}
5050
5051static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
5052 cpumask_t *new_mask)
5053{
5054 if (len < sizeof(cpumask_t)) {
5055 memset(new_mask, 0, sizeof(cpumask_t));
5056 } else if (len > sizeof(cpumask_t)) {
5057 len = sizeof(cpumask_t);
5058 }
5059 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
5060}
5061
5062/**
5063 * sys_sched_setaffinity - set the cpu affinity of a process
5064 * @pid: pid of the process
5065 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5066 * @user_mask_ptr: user-space pointer to the new cpu mask
5067 */
5068asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
5069 unsigned long __user *user_mask_ptr)
5070{
5071 cpumask_t new_mask;
5072 int retval;
5073
5074 retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
5075 if (retval)
5076 return retval;
5077
Mike Travisb53e9212008-04-04 18:11:08 -07005078 return sched_setaffinity(pid, &new_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005079}
5080
Linus Torvalds1da177e2005-04-16 15:20:36 -07005081long sched_getaffinity(pid_t pid, cpumask_t *mask)
5082{
Ingo Molnar36c8b582006-07-03 00:25:41 -07005083 struct task_struct *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005084 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005085
Gautham R Shenoy95402b32008-01-25 21:08:02 +01005086 get_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005087 read_lock(&tasklist_lock);
5088
5089 retval = -ESRCH;
5090 p = find_process_by_pid(pid);
5091 if (!p)
5092 goto out_unlock;
5093
David Quigleye7834f82006-06-23 02:03:59 -07005094 retval = security_task_getscheduler(p);
5095 if (retval)
5096 goto out_unlock;
5097
Jack Steiner2f7016d2006-02-01 03:05:18 -08005098 cpus_and(*mask, p->cpus_allowed, cpu_online_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005099
5100out_unlock:
5101 read_unlock(&tasklist_lock);
Gautham R Shenoy95402b32008-01-25 21:08:02 +01005102 put_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005103
Ulrich Drepper9531b622007-08-09 11:16:46 +02005104 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005105}
5106
5107/**
5108 * sys_sched_getaffinity - get the cpu affinity of a process
5109 * @pid: pid of the process
5110 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
5111 * @user_mask_ptr: user-space pointer to hold the current cpu mask
5112 */
5113asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
5114 unsigned long __user *user_mask_ptr)
5115{
5116 int ret;
5117 cpumask_t mask;
5118
5119 if (len < sizeof(cpumask_t))
5120 return -EINVAL;
5121
5122 ret = sched_getaffinity(pid, &mask);
5123 if (ret < 0)
5124 return ret;
5125
5126 if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
5127 return -EFAULT;
5128
5129 return sizeof(cpumask_t);
5130}
5131
5132/**
5133 * sys_sched_yield - yield the current processor to other threads.
5134 *
Ingo Molnardd41f592007-07-09 18:51:59 +02005135 * This function yields the current CPU to other tasks. If there are no
5136 * other threads running on this CPU then this function will return.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005137 */
5138asmlinkage long sys_sched_yield(void)
5139{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005140 struct rq *rq = this_rq_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005141
Ingo Molnar2d723762007-10-15 17:00:12 +02005142 schedstat_inc(rq, yld_count);
Dmitry Adamushko4530d7a2007-10-15 17:00:08 +02005143 current->sched_class->yield_task(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005144
5145 /*
5146 * Since we are going to call schedule() anyway, there's
5147 * no need to preempt or enable interrupts:
5148 */
5149 __release(rq->lock);
Ingo Molnar8a25d5d2006-07-03 00:24:54 -07005150 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005151 _raw_spin_unlock(&rq->lock);
5152 preempt_enable_no_resched();
5153
5154 schedule();
5155
5156 return 0;
5157}
5158
Andrew Mortone7b38402006-06-30 01:56:00 -07005159static void __cond_resched(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005160{
Ingo Molnar8e0a43d2006-06-23 02:05:23 -07005161#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
5162 __might_sleep(__FILE__, __LINE__);
5163#endif
Ingo Molnar5bbcfd92005-07-07 17:57:04 -07005164 /*
5165 * The BKS might be reacquired before we have dropped
5166 * PREEMPT_ACTIVE, which could trigger a second
5167 * cond_resched() call.
5168 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07005169 do {
5170 add_preempt_count(PREEMPT_ACTIVE);
5171 schedule();
5172 sub_preempt_count(PREEMPT_ACTIVE);
5173 } while (need_resched());
5174}
5175
Herbert Xu02b67cc32008-01-25 21:08:28 +01005176int __sched _cond_resched(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005177{
Ingo Molnar94142322006-12-29 16:48:13 -08005178 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
5179 system_state == SYSTEM_RUNNING) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07005180 __cond_resched();
5181 return 1;
5182 }
5183 return 0;
5184}
Herbert Xu02b67cc32008-01-25 21:08:28 +01005185EXPORT_SYMBOL(_cond_resched);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005186
5187/*
5188 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
5189 * call schedule, and on return reacquire the lock.
5190 *
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005191 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
Linus Torvalds1da177e2005-04-16 15:20:36 -07005192 * operations here to prevent schedule() from being called twice (once via
5193 * spin_unlock(), once by hand).
5194 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07005195int cond_resched_lock(spinlock_t *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005196{
Nick Piggin95c354f2008-01-30 13:31:20 +01005197 int resched = need_resched() && system_state == SYSTEM_RUNNING;
Jan Kara6df3cec2005-06-13 15:52:32 -07005198 int ret = 0;
5199
Nick Piggin95c354f2008-01-30 13:31:20 +01005200 if (spin_needbreak(lock) || resched) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07005201 spin_unlock(lock);
Nick Piggin95c354f2008-01-30 13:31:20 +01005202 if (resched && need_resched())
5203 __cond_resched();
5204 else
5205 cpu_relax();
Jan Kara6df3cec2005-06-13 15:52:32 -07005206 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005207 spin_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005208 }
Jan Kara6df3cec2005-06-13 15:52:32 -07005209 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005210}
Linus Torvalds1da177e2005-04-16 15:20:36 -07005211EXPORT_SYMBOL(cond_resched_lock);
5212
5213int __sched cond_resched_softirq(void)
5214{
5215 BUG_ON(!in_softirq());
5216
Ingo Molnar94142322006-12-29 16:48:13 -08005217 if (need_resched() && system_state == SYSTEM_RUNNING) {
Thomas Gleixner98d825672007-05-23 13:58:18 -07005218 local_bh_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005219 __cond_resched();
5220 local_bh_disable();
5221 return 1;
5222 }
5223 return 0;
5224}
Linus Torvalds1da177e2005-04-16 15:20:36 -07005225EXPORT_SYMBOL(cond_resched_softirq);
5226
Linus Torvalds1da177e2005-04-16 15:20:36 -07005227/**
5228 * yield - yield the current processor to other threads.
5229 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08005230 * This is a shortcut for kernel-space yielding - it marks the
Linus Torvalds1da177e2005-04-16 15:20:36 -07005231 * thread runnable and calls sys_sched_yield().
5232 */
5233void __sched yield(void)
5234{
5235 set_current_state(TASK_RUNNING);
5236 sys_sched_yield();
5237}
Linus Torvalds1da177e2005-04-16 15:20:36 -07005238EXPORT_SYMBOL(yield);
5239
5240/*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005241 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
Linus Torvalds1da177e2005-04-16 15:20:36 -07005242 * that process accounting knows that this is a task in IO wait state.
5243 *
5244 * But don't do that if it is a deliberate, throttling IO wait (this task
5245 * has set its backing_dev_info: the queue against which it should throttle)
5246 */
5247void __sched io_schedule(void)
5248{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005249 struct rq *rq = &__raw_get_cpu_var(runqueues);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005250
Shailabh Nagar0ff92242006-07-14 00:24:37 -07005251 delayacct_blkio_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005252 atomic_inc(&rq->nr_iowait);
5253 schedule();
5254 atomic_dec(&rq->nr_iowait);
Shailabh Nagar0ff92242006-07-14 00:24:37 -07005255 delayacct_blkio_end();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005256}
Linus Torvalds1da177e2005-04-16 15:20:36 -07005257EXPORT_SYMBOL(io_schedule);
5258
5259long __sched io_schedule_timeout(long timeout)
5260{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005261 struct rq *rq = &__raw_get_cpu_var(runqueues);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005262 long ret;
5263
Shailabh Nagar0ff92242006-07-14 00:24:37 -07005264 delayacct_blkio_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005265 atomic_inc(&rq->nr_iowait);
5266 ret = schedule_timeout(timeout);
5267 atomic_dec(&rq->nr_iowait);
Shailabh Nagar0ff92242006-07-14 00:24:37 -07005268 delayacct_blkio_end();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005269 return ret;
5270}
5271
5272/**
5273 * sys_sched_get_priority_max - return maximum RT priority.
5274 * @policy: scheduling class.
5275 *
5276 * this syscall returns the maximum rt_priority that can be used
5277 * by a given scheduling class.
5278 */
5279asmlinkage long sys_sched_get_priority_max(int policy)
5280{
5281 int ret = -EINVAL;
5282
5283 switch (policy) {
5284 case SCHED_FIFO:
5285 case SCHED_RR:
5286 ret = MAX_USER_RT_PRIO-1;
5287 break;
5288 case SCHED_NORMAL:
Ingo Molnarb0a94992006-01-14 13:20:41 -08005289 case SCHED_BATCH:
Ingo Molnardd41f592007-07-09 18:51:59 +02005290 case SCHED_IDLE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07005291 ret = 0;
5292 break;
5293 }
5294 return ret;
5295}
5296
5297/**
5298 * sys_sched_get_priority_min - return minimum RT priority.
5299 * @policy: scheduling class.
5300 *
5301 * this syscall returns the minimum rt_priority that can be used
5302 * by a given scheduling class.
5303 */
5304asmlinkage long sys_sched_get_priority_min(int policy)
5305{
5306 int ret = -EINVAL;
5307
5308 switch (policy) {
5309 case SCHED_FIFO:
5310 case SCHED_RR:
5311 ret = 1;
5312 break;
5313 case SCHED_NORMAL:
Ingo Molnarb0a94992006-01-14 13:20:41 -08005314 case SCHED_BATCH:
Ingo Molnardd41f592007-07-09 18:51:59 +02005315 case SCHED_IDLE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07005316 ret = 0;
5317 }
5318 return ret;
5319}
5320
5321/**
5322 * sys_sched_rr_get_interval - return the default timeslice of a process.
5323 * @pid: pid of the process.
5324 * @interval: userspace pointer to the timeslice value.
5325 *
5326 * this syscall writes the default timeslice value of a given process
5327 * into the user-space timespec buffer. A value of '0' means infinity.
5328 */
5329asmlinkage
5330long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
5331{
Ingo Molnar36c8b582006-07-03 00:25:41 -07005332 struct task_struct *p;
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02005333 unsigned int time_slice;
Andi Kleen3a5c3592007-10-15 17:00:14 +02005334 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005335 struct timespec t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005336
5337 if (pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02005338 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005339
5340 retval = -ESRCH;
5341 read_lock(&tasklist_lock);
5342 p = find_process_by_pid(pid);
5343 if (!p)
5344 goto out_unlock;
5345
5346 retval = security_task_getscheduler(p);
5347 if (retval)
5348 goto out_unlock;
5349
Ingo Molnar77034932007-12-04 17:04:39 +01005350 /*
5351 * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER
5352 * tasks that are on an otherwise idle runqueue:
5353 */
5354 time_slice = 0;
5355 if (p->policy == SCHED_RR) {
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02005356 time_slice = DEF_TIMESLICE;
Miao Xie1868f952008-03-07 09:35:06 +08005357 } else if (p->policy != SCHED_FIFO) {
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02005358 struct sched_entity *se = &p->se;
5359 unsigned long flags;
5360 struct rq *rq;
5361
5362 rq = task_rq_lock(p, &flags);
Ingo Molnar77034932007-12-04 17:04:39 +01005363 if (rq->cfs.load.weight)
5364 time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se));
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02005365 task_rq_unlock(rq, &flags);
5366 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07005367 read_unlock(&tasklist_lock);
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02005368 jiffies_to_timespec(time_slice, &t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005369 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005370 return retval;
Andi Kleen3a5c3592007-10-15 17:00:14 +02005371
Linus Torvalds1da177e2005-04-16 15:20:36 -07005372out_unlock:
5373 read_unlock(&tasklist_lock);
5374 return retval;
5375}
5376
Andreas Mohr2ed6e342006-07-10 04:43:52 -07005377static const char stat_nam[] = "RSDTtZX";
Ingo Molnar36c8b582006-07-03 00:25:41 -07005378
Ingo Molnar82a1fcb2008-01-25 21:08:02 +01005379void sched_show_task(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005380{
Linus Torvalds1da177e2005-04-16 15:20:36 -07005381 unsigned long free = 0;
Ingo Molnar36c8b582006-07-03 00:25:41 -07005382 unsigned state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005383
Linus Torvalds1da177e2005-04-16 15:20:36 -07005384 state = p->state ? __ffs(p->state) + 1 : 0;
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005385 printk(KERN_INFO "%-13.13s %c", p->comm,
Andreas Mohr2ed6e342006-07-10 04:43:52 -07005386 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
Ingo Molnar4bd77322007-07-11 21:21:47 +02005387#if BITS_PER_LONG == 32
Linus Torvalds1da177e2005-04-16 15:20:36 -07005388 if (state == TASK_RUNNING)
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005389 printk(KERN_CONT " running ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005390 else
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005391 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005392#else
5393 if (state == TASK_RUNNING)
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005394 printk(KERN_CONT " running task ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005395 else
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005396 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005397#endif
5398#ifdef CONFIG_DEBUG_STACK_USAGE
5399 {
Al Viro10ebffd2005-11-13 16:06:56 -08005400 unsigned long *n = end_of_stack(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005401 while (!*n)
5402 n++;
Al Viro10ebffd2005-11-13 16:06:56 -08005403 free = (unsigned long)n - (unsigned long)end_of_stack(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005404 }
5405#endif
Pavel Emelyanovba25f9d2007-10-18 23:40:40 -07005406 printk(KERN_CONT "%5lu %5d %6d\n", free,
Roland McGrathfcfd50a2008-01-09 00:03:23 -08005407 task_pid_nr(p), task_pid_nr(p->real_parent));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005408
Nick Piggin5fb5e6d2008-01-25 21:08:34 +01005409 show_stack(p, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005410}
5411
Ingo Molnare59e2ae2006-12-06 20:35:59 -08005412void show_state_filter(unsigned long state_filter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005413{
Ingo Molnar36c8b582006-07-03 00:25:41 -07005414 struct task_struct *g, *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005415
Ingo Molnar4bd77322007-07-11 21:21:47 +02005416#if BITS_PER_LONG == 32
5417 printk(KERN_INFO
5418 " task PC stack pid father\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005419#else
Ingo Molnar4bd77322007-07-11 21:21:47 +02005420 printk(KERN_INFO
5421 " task PC stack pid father\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005422#endif
5423 read_lock(&tasklist_lock);
5424 do_each_thread(g, p) {
5425 /*
5426 * reset the NMI-timeout, listing all files on a slow
5427 * console might take alot of time:
5428 */
5429 touch_nmi_watchdog();
Ingo Molnar39bc89f2007-04-25 20:50:03 -07005430 if (!state_filter || (p->state & state_filter))
Ingo Molnar82a1fcb2008-01-25 21:08:02 +01005431 sched_show_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005432 } while_each_thread(g, p);
5433
Jeremy Fitzhardinge04c91672007-05-08 00:28:05 -07005434 touch_all_softlockup_watchdogs();
5435
Ingo Molnardd41f592007-07-09 18:51:59 +02005436#ifdef CONFIG_SCHED_DEBUG
5437 sysrq_sched_debug_show();
5438#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07005439 read_unlock(&tasklist_lock);
Ingo Molnare59e2ae2006-12-06 20:35:59 -08005440 /*
5441 * Only show locks if all tasks are dumped:
5442 */
5443 if (state_filter == -1)
5444 debug_show_all_locks();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005445}
5446
Ingo Molnar1df21052007-07-09 18:51:58 +02005447void __cpuinit init_idle_bootup_task(struct task_struct *idle)
5448{
Ingo Molnardd41f592007-07-09 18:51:59 +02005449 idle->sched_class = &idle_sched_class;
Ingo Molnar1df21052007-07-09 18:51:58 +02005450}
5451
Ingo Molnarf340c0d2005-06-28 16:40:42 +02005452/**
5453 * init_idle - set up an idle thread for a given CPU
5454 * @idle: task in question
5455 * @cpu: cpu the idle task belongs to
5456 *
5457 * NOTE: this function does not set the idle thread's NEED_RESCHED
5458 * flag, to make booting more robust.
5459 */
Nick Piggin5c1e1762006-10-03 01:14:04 -07005460void __cpuinit init_idle(struct task_struct *idle, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005461{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005462 struct rq *rq = cpu_rq(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005463 unsigned long flags;
5464
Ingo Molnardd41f592007-07-09 18:51:59 +02005465 __sched_fork(idle);
5466 idle->se.exec_start = sched_clock();
5467
Ingo Molnarb29739f2006-06-27 02:54:51 -07005468 idle->prio = idle->normal_prio = MAX_PRIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005469 idle->cpus_allowed = cpumask_of_cpu(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02005470 __set_task_cpu(idle, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005471
5472 spin_lock_irqsave(&rq->lock, flags);
5473 rq->curr = rq->idle = idle;
Nick Piggin4866cde2005-06-25 14:57:23 -07005474#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
5475 idle->oncpu = 1;
5476#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07005477 spin_unlock_irqrestore(&rq->lock, flags);
5478
5479 /* Set the preempt count _outside_ the spinlocks! */
Linus Torvalds8e3e0762008-05-10 20:58:02 -07005480#if defined(CONFIG_PREEMPT)
5481 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
5482#else
Al Viroa1261f52005-11-13 16:06:55 -08005483 task_thread_info(idle)->preempt_count = 0;
Linus Torvalds8e3e0762008-05-10 20:58:02 -07005484#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02005485 /*
5486 * The idle tasks have their own, simple scheduling class:
5487 */
5488 idle->sched_class = &idle_sched_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005489}
5490
5491/*
5492 * In a system that switches off the HZ timer nohz_cpu_mask
5493 * indicates which cpus entered this state. This is used
5494 * in the rcu update to wait only for active cpus. For system
5495 * which do not switch off the HZ timer nohz_cpu_mask should
5496 * always be CPU_MASK_NONE.
5497 */
5498cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
5499
Ingo Molnar19978ca2007-11-09 22:39:38 +01005500/*
5501 * Increase the granularity value when there are more CPUs,
5502 * because with more CPUs the 'effective latency' as visible
5503 * to users decreases. But the relationship is not linear,
5504 * so pick a second-best guess by going with the log2 of the
5505 * number of CPUs.
5506 *
5507 * This idea comes from the SD scheduler of Con Kolivas:
5508 */
5509static inline void sched_init_granularity(void)
5510{
5511 unsigned int factor = 1 + ilog2(num_online_cpus());
5512 const unsigned long limit = 200000000;
5513
5514 sysctl_sched_min_granularity *= factor;
5515 if (sysctl_sched_min_granularity > limit)
5516 sysctl_sched_min_granularity = limit;
5517
5518 sysctl_sched_latency *= factor;
5519 if (sysctl_sched_latency > limit)
5520 sysctl_sched_latency = limit;
5521
5522 sysctl_sched_wakeup_granularity *= factor;
Ingo Molnar19978ca2007-11-09 22:39:38 +01005523}
5524
Linus Torvalds1da177e2005-04-16 15:20:36 -07005525#ifdef CONFIG_SMP
5526/*
5527 * This is how migration works:
5528 *
Ingo Molnar70b97a72006-07-03 00:25:42 -07005529 * 1) we queue a struct migration_req structure in the source CPU's
Linus Torvalds1da177e2005-04-16 15:20:36 -07005530 * runqueue and wake up that CPU's migration thread.
5531 * 2) we down() the locked semaphore => thread blocks.
5532 * 3) migration thread wakes up (implicitly it forces the migrated
5533 * thread off the CPU)
5534 * 4) it gets the migration request and checks whether the migrated
5535 * task is still in the wrong runqueue.
5536 * 5) if it's in the wrong runqueue then the migration thread removes
5537 * it and puts it into the right queue.
5538 * 6) migration thread up()s the semaphore.
5539 * 7) we wake up and the migration is done.
5540 */
5541
5542/*
5543 * Change a given task's CPU affinity. Migrate the thread to a
5544 * proper CPU and schedule it away if the CPU it's executing on
5545 * is removed from the allowed bitmask.
5546 *
5547 * NOTE: the caller must have a valid reference to the task, the
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005548 * task must not exit() & deallocate itself prematurely. The
Linus Torvalds1da177e2005-04-16 15:20:36 -07005549 * call is not atomic; no spinlocks may be held.
5550 */
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005551int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005552{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005553 struct migration_req req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005554 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005555 struct rq *rq;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005556 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005557
5558 rq = task_rq_lock(p, &flags);
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005559 if (!cpus_intersects(*new_mask, cpu_online_map)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07005560 ret = -EINVAL;
5561 goto out;
5562 }
5563
David Rientjes9985b0b2008-06-05 12:57:11 -07005564 if (unlikely((p->flags & PF_THREAD_BOUND) && p != current &&
5565 !cpus_equal(p->cpus_allowed, *new_mask))) {
5566 ret = -EINVAL;
5567 goto out;
5568 }
5569
Gregory Haskins73fe6aa2008-01-25 21:08:07 +01005570 if (p->sched_class->set_cpus_allowed)
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005571 p->sched_class->set_cpus_allowed(p, new_mask);
Gregory Haskins73fe6aa2008-01-25 21:08:07 +01005572 else {
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005573 p->cpus_allowed = *new_mask;
5574 p->rt.nr_cpus_allowed = cpus_weight(*new_mask);
Gregory Haskins73fe6aa2008-01-25 21:08:07 +01005575 }
5576
Linus Torvalds1da177e2005-04-16 15:20:36 -07005577 /* Can the task run on the task's current CPU? If so, we're done */
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005578 if (cpu_isset(task_cpu(p), *new_mask))
Linus Torvalds1da177e2005-04-16 15:20:36 -07005579 goto out;
5580
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005581 if (migrate_task(p, any_online_cpu(*new_mask), &req)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07005582 /* Need help from migration thread: drop lock and wait. */
5583 task_rq_unlock(rq, &flags);
5584 wake_up_process(rq->migration_thread);
5585 wait_for_completion(&req.done);
5586 tlb_migrate_finish(p->mm);
5587 return 0;
5588 }
5589out:
5590 task_rq_unlock(rq, &flags);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005591
Linus Torvalds1da177e2005-04-16 15:20:36 -07005592 return ret;
5593}
Mike Traviscd8ba7c2008-03-26 14:23:49 -07005594EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005595
5596/*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005597 * Move (not current) task off this cpu, onto dest cpu. We're doing
Linus Torvalds1da177e2005-04-16 15:20:36 -07005598 * this because either it can't run here any more (set_cpus_allowed()
5599 * away from this CPU, or CPU going down), or because we're
5600 * attempting to rebalance this task on exec (sched_exec).
5601 *
5602 * So we race with normal scheduler movements, but that's OK, as long
5603 * as the task is no longer on this CPU.
Kirill Korotaevefc30812006-06-27 02:54:32 -07005604 *
5605 * Returns non-zero if task was successfully migrated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005606 */
Kirill Korotaevefc30812006-06-27 02:54:32 -07005607static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005608{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005609 struct rq *rq_dest, *rq_src;
Ingo Molnardd41f592007-07-09 18:51:59 +02005610 int ret = 0, on_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005611
5612 if (unlikely(cpu_is_offline(dest_cpu)))
Kirill Korotaevefc30812006-06-27 02:54:32 -07005613 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005614
5615 rq_src = cpu_rq(src_cpu);
5616 rq_dest = cpu_rq(dest_cpu);
5617
5618 double_rq_lock(rq_src, rq_dest);
5619 /* Already moved. */
5620 if (task_cpu(p) != src_cpu)
5621 goto out;
5622 /* Affinity changed (again). */
5623 if (!cpu_isset(dest_cpu, p->cpus_allowed))
5624 goto out;
5625
Ingo Molnardd41f592007-07-09 18:51:59 +02005626 on_rq = p->se.on_rq;
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02005627 if (on_rq)
Ingo Molnar2e1cb742007-08-09 11:16:49 +02005628 deactivate_task(rq_src, p, 0);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02005629
Linus Torvalds1da177e2005-04-16 15:20:36 -07005630 set_task_cpu(p, dest_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02005631 if (on_rq) {
5632 activate_task(rq_dest, p, 0);
5633 check_preempt_curr(rq_dest, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005634 }
Kirill Korotaevefc30812006-06-27 02:54:32 -07005635 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005636out:
5637 double_rq_unlock(rq_src, rq_dest);
Kirill Korotaevefc30812006-06-27 02:54:32 -07005638 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005639}
5640
5641/*
5642 * migration_thread - this is a highprio system thread that performs
5643 * thread migration by bumping thread off CPU then 'pushing' onto
5644 * another runqueue.
5645 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07005646static int migration_thread(void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005647{
Linus Torvalds1da177e2005-04-16 15:20:36 -07005648 int cpu = (long)data;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005649 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005650
5651 rq = cpu_rq(cpu);
5652 BUG_ON(rq->migration_thread != current);
5653
5654 set_current_state(TASK_INTERRUPTIBLE);
5655 while (!kthread_should_stop()) {
Ingo Molnar70b97a72006-07-03 00:25:42 -07005656 struct migration_req *req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005657 struct list_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005658
Linus Torvalds1da177e2005-04-16 15:20:36 -07005659 spin_lock_irq(&rq->lock);
5660
5661 if (cpu_is_offline(cpu)) {
5662 spin_unlock_irq(&rq->lock);
5663 goto wait_to_die;
5664 }
5665
5666 if (rq->active_balance) {
5667 active_load_balance(rq, cpu);
5668 rq->active_balance = 0;
5669 }
5670
5671 head = &rq->migration_queue;
5672
5673 if (list_empty(head)) {
5674 spin_unlock_irq(&rq->lock);
5675 schedule();
5676 set_current_state(TASK_INTERRUPTIBLE);
5677 continue;
5678 }
Ingo Molnar70b97a72006-07-03 00:25:42 -07005679 req = list_entry(head->next, struct migration_req, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005680 list_del_init(head->next);
5681
Nick Piggin674311d2005-06-25 14:57:27 -07005682 spin_unlock(&rq->lock);
5683 __migrate_task(req->task, cpu, req->dest_cpu);
5684 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005685
5686 complete(&req->done);
5687 }
5688 __set_current_state(TASK_RUNNING);
5689 return 0;
5690
5691wait_to_die:
5692 /* Wait for kthread_stop */
5693 set_current_state(TASK_INTERRUPTIBLE);
5694 while (!kthread_should_stop()) {
5695 schedule();
5696 set_current_state(TASK_INTERRUPTIBLE);
5697 }
5698 __set_current_state(TASK_RUNNING);
5699 return 0;
5700}
5701
5702#ifdef CONFIG_HOTPLUG_CPU
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005703
5704static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
5705{
5706 int ret;
5707
5708 local_irq_disable();
5709 ret = __migrate_task(p, src_cpu, dest_cpu);
5710 local_irq_enable();
5711 return ret;
5712}
5713
Kirill Korotaev054b9102006-12-10 02:20:11 -08005714/*
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +02005715 * Figure out where task on dead CPU should go, use force if necessary.
Kirill Korotaev054b9102006-12-10 02:20:11 -08005716 * NOTE: interrupts should be disabled by the caller
5717 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005718static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005719{
Kirill Korotaevefc30812006-06-27 02:54:32 -07005720 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005721 cpumask_t mask;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005722 struct rq *rq;
5723 int dest_cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005724
Andi Kleen3a5c3592007-10-15 17:00:14 +02005725 do {
5726 /* On same node? */
5727 mask = node_to_cpumask(cpu_to_node(dead_cpu));
5728 cpus_and(mask, mask, p->cpus_allowed);
5729 dest_cpu = any_online_cpu(mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005730
Andi Kleen3a5c3592007-10-15 17:00:14 +02005731 /* On any allowed CPU? */
Mike Travis434d53b2008-04-04 18:11:04 -07005732 if (dest_cpu >= nr_cpu_ids)
Andi Kleen3a5c3592007-10-15 17:00:14 +02005733 dest_cpu = any_online_cpu(p->cpus_allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005734
Andi Kleen3a5c3592007-10-15 17:00:14 +02005735 /* No more Mr. Nice Guy. */
Mike Travis434d53b2008-04-04 18:11:04 -07005736 if (dest_cpu >= nr_cpu_ids) {
Mike Travisf9a86fc2008-04-04 18:11:07 -07005737 cpumask_t cpus_allowed;
5738
5739 cpuset_cpus_allowed_locked(p, &cpus_allowed);
Cliff Wickman470fd642007-10-18 23:40:46 -07005740 /*
5741 * Try to stay on the same cpuset, where the
5742 * current cpuset may be a subset of all cpus.
5743 * The cpuset_cpus_allowed_locked() variant of
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005744 * cpuset_cpus_allowed() will not block. It must be
Cliff Wickman470fd642007-10-18 23:40:46 -07005745 * called within calls to cpuset_lock/cpuset_unlock.
5746 */
Andi Kleen3a5c3592007-10-15 17:00:14 +02005747 rq = task_rq_lock(p, &flags);
Cliff Wickman470fd642007-10-18 23:40:46 -07005748 p->cpus_allowed = cpus_allowed;
Andi Kleen3a5c3592007-10-15 17:00:14 +02005749 dest_cpu = any_online_cpu(p->cpus_allowed);
5750 task_rq_unlock(rq, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005751
Andi Kleen3a5c3592007-10-15 17:00:14 +02005752 /*
5753 * Don't tell them about moving exiting tasks or
5754 * kernel threads (both mm NULL), since they never
5755 * leave kernel.
5756 */
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005757 if (p->mm && printk_ratelimit()) {
Andi Kleen3a5c3592007-10-15 17:00:14 +02005758 printk(KERN_INFO "process %d (%s) no "
5759 "longer affine to cpu%d\n",
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005760 task_pid_nr(p), p->comm, dead_cpu);
5761 }
Andi Kleen3a5c3592007-10-15 17:00:14 +02005762 }
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005763 } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005764}
5765
5766/*
5767 * While a dead CPU has no uninterruptible tasks queued at this point,
5768 * it might still have a nonzero ->nr_uninterruptible counter, because
5769 * for performance reasons the counter is not stricly tracking tasks to
5770 * their home CPUs. So we just add the counter to another CPU's counter,
5771 * to keep the global sum constant after CPU-down:
5772 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07005773static void migrate_nr_uninterruptible(struct rq *rq_src)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005774{
Mike Travis7c16ec52008-04-04 18:11:11 -07005775 struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005776 unsigned long flags;
5777
5778 local_irq_save(flags);
5779 double_rq_lock(rq_src, rq_dest);
5780 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5781 rq_src->nr_uninterruptible = 0;
5782 double_rq_unlock(rq_src, rq_dest);
5783 local_irq_restore(flags);
5784}
5785
5786/* Run through task list and migrate tasks from the dead cpu. */
5787static void migrate_live_tasks(int src_cpu)
5788{
Ingo Molnar48f24c42006-07-03 00:25:40 -07005789 struct task_struct *p, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005790
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005791 read_lock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005792
Ingo Molnar48f24c42006-07-03 00:25:40 -07005793 do_each_thread(t, p) {
5794 if (p == current)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005795 continue;
5796
Ingo Molnar48f24c42006-07-03 00:25:40 -07005797 if (task_cpu(p) == src_cpu)
5798 move_task_off_dead_cpu(src_cpu, p);
5799 } while_each_thread(t, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005800
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005801 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005802}
5803
Ingo Molnardd41f592007-07-09 18:51:59 +02005804/*
5805 * Schedules idle task to be the next runnable task on current CPU.
Dmitry Adamushko94bc9a72007-11-15 20:57:40 +01005806 * It does so by boosting its priority to highest possible.
5807 * Used by CPU offline code.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005808 */
5809void sched_idle_next(void)
5810{
Ingo Molnar48f24c42006-07-03 00:25:40 -07005811 int this_cpu = smp_processor_id();
Ingo Molnar70b97a72006-07-03 00:25:42 -07005812 struct rq *rq = cpu_rq(this_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005813 struct task_struct *p = rq->idle;
5814 unsigned long flags;
5815
5816 /* cpu has to be offline */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005817 BUG_ON(cpu_online(this_cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005818
Ingo Molnar48f24c42006-07-03 00:25:40 -07005819 /*
5820 * Strictly not necessary since rest of the CPUs are stopped by now
5821 * and interrupts disabled on the current cpu.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005822 */
5823 spin_lock_irqsave(&rq->lock, flags);
5824
Ingo Molnardd41f592007-07-09 18:51:59 +02005825 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005826
Dmitry Adamushko94bc9a72007-11-15 20:57:40 +01005827 update_rq_clock(rq);
5828 activate_task(rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005829
5830 spin_unlock_irqrestore(&rq->lock, flags);
5831}
5832
Ingo Molnar48f24c42006-07-03 00:25:40 -07005833/*
5834 * Ensures that the idle task is using init_mm right before its cpu goes
Linus Torvalds1da177e2005-04-16 15:20:36 -07005835 * offline.
5836 */
5837void idle_task_exit(void)
5838{
5839 struct mm_struct *mm = current->active_mm;
5840
5841 BUG_ON(cpu_online(smp_processor_id()));
5842
5843 if (mm != &init_mm)
5844 switch_mm(mm, &init_mm, current);
5845 mmdrop(mm);
5846}
5847
Kirill Korotaev054b9102006-12-10 02:20:11 -08005848/* called under rq->lock with disabled interrupts */
Ingo Molnar36c8b582006-07-03 00:25:41 -07005849static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005850{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005851 struct rq *rq = cpu_rq(dead_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005852
5853 /* Must be exiting, otherwise would be on tasklist. */
Eugene Teo270f7222007-10-18 23:40:38 -07005854 BUG_ON(!p->exit_state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005855
5856 /* Cannot have done final schedule yet: would have vanished. */
Oleg Nesterovc394cc92006-09-29 02:01:11 -07005857 BUG_ON(p->state == TASK_DEAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005858
Ingo Molnar48f24c42006-07-03 00:25:40 -07005859 get_task_struct(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005860
5861 /*
5862 * Drop lock around migration; if someone else moves it,
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005863 * that's OK. No task can be added to this CPU, so iteration is
Linus Torvalds1da177e2005-04-16 15:20:36 -07005864 * fine.
5865 */
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005866 spin_unlock_irq(&rq->lock);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005867 move_task_off_dead_cpu(dead_cpu, p);
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005868 spin_lock_irq(&rq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005869
Ingo Molnar48f24c42006-07-03 00:25:40 -07005870 put_task_struct(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005871}
5872
5873/* release_task() removes task from tasklist, so we won't find dead tasks. */
5874static void migrate_dead_tasks(unsigned int dead_cpu)
5875{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005876 struct rq *rq = cpu_rq(dead_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02005877 struct task_struct *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005878
Ingo Molnardd41f592007-07-09 18:51:59 +02005879 for ( ; ; ) {
5880 if (!rq->nr_running)
5881 break;
Ingo Molnara8e504d2007-08-09 11:16:47 +02005882 update_rq_clock(rq);
Ingo Molnarff95f3d2007-08-09 11:16:49 +02005883 next = pick_next_task(rq, rq->curr);
Ingo Molnardd41f592007-07-09 18:51:59 +02005884 if (!next)
5885 break;
5886 migrate_dead(dead_cpu, next);
Nick Piggine692ab52007-07-26 13:40:43 +02005887
Linus Torvalds1da177e2005-04-16 15:20:36 -07005888 }
5889}
5890#endif /* CONFIG_HOTPLUG_CPU */
5891
Nick Piggine692ab52007-07-26 13:40:43 +02005892#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5893
5894static struct ctl_table sd_ctl_dir[] = {
Alexey Dobriyane0361852007-08-09 11:16:46 +02005895 {
5896 .procname = "sched_domain",
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005897 .mode = 0555,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005898 },
Ingo Molnar38605ca2007-10-29 21:18:11 +01005899 {0, },
Nick Piggine692ab52007-07-26 13:40:43 +02005900};
5901
5902static struct ctl_table sd_ctl_root[] = {
Alexey Dobriyane0361852007-08-09 11:16:46 +02005903 {
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005904 .ctl_name = CTL_KERN,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005905 .procname = "kernel",
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005906 .mode = 0555,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005907 .child = sd_ctl_dir,
5908 },
Ingo Molnar38605ca2007-10-29 21:18:11 +01005909 {0, },
Nick Piggine692ab52007-07-26 13:40:43 +02005910};
5911
5912static struct ctl_table *sd_alloc_ctl_entry(int n)
5913{
5914 struct ctl_table *entry =
Milton Miller5cf9f062007-10-15 17:00:19 +02005915 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
Nick Piggine692ab52007-07-26 13:40:43 +02005916
Nick Piggine692ab52007-07-26 13:40:43 +02005917 return entry;
5918}
5919
Milton Miller6382bc92007-10-15 17:00:19 +02005920static void sd_free_ctl_entry(struct ctl_table **tablep)
5921{
Milton Millercd790072007-10-17 16:55:11 +02005922 struct ctl_table *entry;
Milton Miller6382bc92007-10-15 17:00:19 +02005923
Milton Millercd790072007-10-17 16:55:11 +02005924 /*
5925 * In the intermediate directories, both the child directory and
5926 * procname are dynamically allocated and could fail but the mode
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01005927 * will always be set. In the lowest directory the names are
Milton Millercd790072007-10-17 16:55:11 +02005928 * static strings and all have proc handlers.
5929 */
5930 for (entry = *tablep; entry->mode; entry++) {
Milton Miller6382bc92007-10-15 17:00:19 +02005931 if (entry->child)
5932 sd_free_ctl_entry(&entry->child);
Milton Millercd790072007-10-17 16:55:11 +02005933 if (entry->proc_handler == NULL)
5934 kfree(entry->procname);
5935 }
Milton Miller6382bc92007-10-15 17:00:19 +02005936
5937 kfree(*tablep);
5938 *tablep = NULL;
5939}
5940
Nick Piggine692ab52007-07-26 13:40:43 +02005941static void
Alexey Dobriyane0361852007-08-09 11:16:46 +02005942set_table_entry(struct ctl_table *entry,
Nick Piggine692ab52007-07-26 13:40:43 +02005943 const char *procname, void *data, int maxlen,
5944 mode_t mode, proc_handler *proc_handler)
5945{
Nick Piggine692ab52007-07-26 13:40:43 +02005946 entry->procname = procname;
5947 entry->data = data;
5948 entry->maxlen = maxlen;
5949 entry->mode = mode;
5950 entry->proc_handler = proc_handler;
5951}
5952
5953static struct ctl_table *
5954sd_alloc_ctl_domain_table(struct sched_domain *sd)
5955{
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005956 struct ctl_table *table = sd_alloc_ctl_entry(12);
Nick Piggine692ab52007-07-26 13:40:43 +02005957
Milton Millerad1cdc12007-10-15 17:00:19 +02005958 if (table == NULL)
5959 return NULL;
5960
Alexey Dobriyane0361852007-08-09 11:16:46 +02005961 set_table_entry(&table[0], "min_interval", &sd->min_interval,
Nick Piggine692ab52007-07-26 13:40:43 +02005962 sizeof(long), 0644, proc_doulongvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005963 set_table_entry(&table[1], "max_interval", &sd->max_interval,
Nick Piggine692ab52007-07-26 13:40:43 +02005964 sizeof(long), 0644, proc_doulongvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005965 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005966 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005967 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005968 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005969 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005970 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005971 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005972 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005973 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005974 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005975 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
Nick Piggine692ab52007-07-26 13:40:43 +02005976 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005977 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
Nick Piggine692ab52007-07-26 13:40:43 +02005978 sizeof(int), 0644, proc_dointvec_minmax);
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005979 set_table_entry(&table[9], "cache_nice_tries",
Nick Piggine692ab52007-07-26 13:40:43 +02005980 &sd->cache_nice_tries,
5981 sizeof(int), 0644, proc_dointvec_minmax);
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005982 set_table_entry(&table[10], "flags", &sd->flags,
Nick Piggine692ab52007-07-26 13:40:43 +02005983 sizeof(int), 0644, proc_dointvec_minmax);
Milton Miller6323469f2007-10-15 17:00:19 +02005984 /* &table[11] is terminator */
Nick Piggine692ab52007-07-26 13:40:43 +02005985
5986 return table;
5987}
5988
Ingo Molnar9a4e7152007-11-28 15:52:56 +01005989static ctl_table *sd_alloc_ctl_cpu_table(int cpu)
Nick Piggine692ab52007-07-26 13:40:43 +02005990{
5991 struct ctl_table *entry, *table;
5992 struct sched_domain *sd;
5993 int domain_num = 0, i;
5994 char buf[32];
5995
5996 for_each_domain(cpu, sd)
5997 domain_num++;
5998 entry = table = sd_alloc_ctl_entry(domain_num + 1);
Milton Millerad1cdc12007-10-15 17:00:19 +02005999 if (table == NULL)
6000 return NULL;
Nick Piggine692ab52007-07-26 13:40:43 +02006001
6002 i = 0;
6003 for_each_domain(cpu, sd) {
6004 snprintf(buf, 32, "domain%d", i);
Nick Piggine692ab52007-07-26 13:40:43 +02006005 entry->procname = kstrdup(buf, GFP_KERNEL);
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02006006 entry->mode = 0555;
Nick Piggine692ab52007-07-26 13:40:43 +02006007 entry->child = sd_alloc_ctl_domain_table(sd);
6008 entry++;
6009 i++;
6010 }
6011 return table;
6012}
6013
6014static struct ctl_table_header *sd_sysctl_header;
Milton Miller6382bc92007-10-15 17:00:19 +02006015static void register_sched_domain_sysctl(void)
Nick Piggine692ab52007-07-26 13:40:43 +02006016{
6017 int i, cpu_num = num_online_cpus();
6018 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
6019 char buf[32];
6020
Milton Miller73785472007-10-24 18:23:48 +02006021 WARN_ON(sd_ctl_dir[0].child);
6022 sd_ctl_dir[0].child = entry;
6023
Milton Millerad1cdc12007-10-15 17:00:19 +02006024 if (entry == NULL)
6025 return;
6026
Milton Miller97b6ea72007-10-15 17:00:19 +02006027 for_each_online_cpu(i) {
Nick Piggine692ab52007-07-26 13:40:43 +02006028 snprintf(buf, 32, "cpu%d", i);
Nick Piggine692ab52007-07-26 13:40:43 +02006029 entry->procname = kstrdup(buf, GFP_KERNEL);
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02006030 entry->mode = 0555;
Nick Piggine692ab52007-07-26 13:40:43 +02006031 entry->child = sd_alloc_ctl_cpu_table(i);
Milton Miller97b6ea72007-10-15 17:00:19 +02006032 entry++;
Nick Piggine692ab52007-07-26 13:40:43 +02006033 }
Milton Miller73785472007-10-24 18:23:48 +02006034
6035 WARN_ON(sd_sysctl_header);
Nick Piggine692ab52007-07-26 13:40:43 +02006036 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
6037}
Milton Miller6382bc92007-10-15 17:00:19 +02006038
Milton Miller73785472007-10-24 18:23:48 +02006039/* may be called multiple times per register */
Milton Miller6382bc92007-10-15 17:00:19 +02006040static void unregister_sched_domain_sysctl(void)
6041{
Milton Miller73785472007-10-24 18:23:48 +02006042 if (sd_sysctl_header)
6043 unregister_sysctl_table(sd_sysctl_header);
Milton Miller6382bc92007-10-15 17:00:19 +02006044 sd_sysctl_header = NULL;
Milton Miller73785472007-10-24 18:23:48 +02006045 if (sd_ctl_dir[0].child)
6046 sd_free_ctl_entry(&sd_ctl_dir[0].child);
Milton Miller6382bc92007-10-15 17:00:19 +02006047}
Nick Piggine692ab52007-07-26 13:40:43 +02006048#else
Milton Miller6382bc92007-10-15 17:00:19 +02006049static void register_sched_domain_sysctl(void)
6050{
6051}
6052static void unregister_sched_domain_sysctl(void)
Nick Piggine692ab52007-07-26 13:40:43 +02006053{
6054}
6055#endif
6056
Gregory Haskins1f11eb62008-06-04 15:04:05 -04006057static void set_rq_online(struct rq *rq)
6058{
6059 if (!rq->online) {
6060 const struct sched_class *class;
6061
6062 cpu_set(rq->cpu, rq->rd->online);
6063 rq->online = 1;
6064
6065 for_each_class(class) {
6066 if (class->rq_online)
6067 class->rq_online(rq);
6068 }
6069 }
6070}
6071
6072static void set_rq_offline(struct rq *rq)
6073{
6074 if (rq->online) {
6075 const struct sched_class *class;
6076
6077 for_each_class(class) {
6078 if (class->rq_offline)
6079 class->rq_offline(rq);
6080 }
6081
6082 cpu_clear(rq->cpu, rq->rd->online);
6083 rq->online = 0;
6084 }
6085}
6086
Linus Torvalds1da177e2005-04-16 15:20:36 -07006087/*
6088 * migration_call - callback that gets triggered when a CPU is added.
6089 * Here we can start up the necessary migration thread for the new CPU.
6090 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07006091static int __cpuinit
6092migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006093{
Linus Torvalds1da177e2005-04-16 15:20:36 -07006094 struct task_struct *p;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006095 int cpu = (long)hcpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006096 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07006097 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006098
6099 switch (action) {
Gautham R Shenoy5be93612007-05-09 02:34:04 -07006100
Linus Torvalds1da177e2005-04-16 15:20:36 -07006101 case CPU_UP_PREPARE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006102 case CPU_UP_PREPARE_FROZEN:
Ingo Molnardd41f592007-07-09 18:51:59 +02006103 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006104 if (IS_ERR(p))
6105 return NOTIFY_BAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006106 kthread_bind(p, cpu);
6107 /* Must be high prio: stop_machine expects to yield to it. */
6108 rq = task_rq_lock(p, &flags);
Ingo Molnardd41f592007-07-09 18:51:59 +02006109 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006110 task_rq_unlock(rq, &flags);
6111 cpu_rq(cpu)->migration_thread = p;
6112 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006113
Linus Torvalds1da177e2005-04-16 15:20:36 -07006114 case CPU_ONLINE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006115 case CPU_ONLINE_FROZEN:
Robert P. J. Day3a4fa0a2007-10-19 23:10:43 +02006116 /* Strictly unnecessary, as first user will wake it. */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006117 wake_up_process(cpu_rq(cpu)->migration_thread);
Gregory Haskins1f94ef52008-03-10 16:52:41 -04006118
6119 /* Update our root-domain */
6120 rq = cpu_rq(cpu);
6121 spin_lock_irqsave(&rq->lock, flags);
6122 if (rq->rd) {
6123 BUG_ON(!cpu_isset(cpu, rq->rd->span));
Gregory Haskins1f11eb62008-06-04 15:04:05 -04006124
6125 set_rq_online(rq);
Gregory Haskins1f94ef52008-03-10 16:52:41 -04006126 }
6127 spin_unlock_irqrestore(&rq->lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006128 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006129
Linus Torvalds1da177e2005-04-16 15:20:36 -07006130#ifdef CONFIG_HOTPLUG_CPU
6131 case CPU_UP_CANCELED:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006132 case CPU_UP_CANCELED_FROZEN:
Heiko Carstensfc75cdf2006-06-25 05:49:10 -07006133 if (!cpu_rq(cpu)->migration_thread)
6134 break;
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006135 /* Unbind it from offline cpu so it can run. Fall thru. */
Heiko Carstensa4c4af72005-11-07 00:58:38 -08006136 kthread_bind(cpu_rq(cpu)->migration_thread,
6137 any_online_cpu(cpu_online_map));
Linus Torvalds1da177e2005-04-16 15:20:36 -07006138 kthread_stop(cpu_rq(cpu)->migration_thread);
6139 cpu_rq(cpu)->migration_thread = NULL;
6140 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006141
Linus Torvalds1da177e2005-04-16 15:20:36 -07006142 case CPU_DEAD:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006143 case CPU_DEAD_FROZEN:
Cliff Wickman470fd642007-10-18 23:40:46 -07006144 cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006145 migrate_live_tasks(cpu);
6146 rq = cpu_rq(cpu);
6147 kthread_stop(rq->migration_thread);
6148 rq->migration_thread = NULL;
6149 /* Idle task back to normal (off runqueue, low prio) */
Oleg Nesterovd2da2722007-10-16 23:30:56 -07006150 spin_lock_irq(&rq->lock);
Ingo Molnara8e504d2007-08-09 11:16:47 +02006151 update_rq_clock(rq);
Ingo Molnar2e1cb742007-08-09 11:16:49 +02006152 deactivate_task(rq, rq->idle, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006153 rq->idle->static_prio = MAX_PRIO;
Ingo Molnardd41f592007-07-09 18:51:59 +02006154 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
6155 rq->idle->sched_class = &idle_sched_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006156 migrate_dead_tasks(cpu);
Oleg Nesterovd2da2722007-10-16 23:30:56 -07006157 spin_unlock_irq(&rq->lock);
Cliff Wickman470fd642007-10-18 23:40:46 -07006158 cpuset_unlock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07006159 migrate_nr_uninterruptible(rq);
6160 BUG_ON(rq->nr_running != 0);
6161
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006162 /*
6163 * No need to migrate the tasks: it was best-effort if
6164 * they didn't take sched_hotcpu_mutex. Just wake up
6165 * the requestors.
6166 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006167 spin_lock_irq(&rq->lock);
6168 while (!list_empty(&rq->migration_queue)) {
Ingo Molnar70b97a72006-07-03 00:25:42 -07006169 struct migration_req *req;
6170
Linus Torvalds1da177e2005-04-16 15:20:36 -07006171 req = list_entry(rq->migration_queue.next,
Ingo Molnar70b97a72006-07-03 00:25:42 -07006172 struct migration_req, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006173 list_del_init(&req->list);
6174 complete(&req->done);
6175 }
6176 spin_unlock_irq(&rq->lock);
6177 break;
Gregory Haskins57d885f2008-01-25 21:08:18 +01006178
Gregory Haskins08f503b2008-03-10 17:59:11 -04006179 case CPU_DYING:
6180 case CPU_DYING_FROZEN:
Gregory Haskins57d885f2008-01-25 21:08:18 +01006181 /* Update our root-domain */
6182 rq = cpu_rq(cpu);
6183 spin_lock_irqsave(&rq->lock, flags);
6184 if (rq->rd) {
6185 BUG_ON(!cpu_isset(cpu, rq->rd->span));
Gregory Haskins1f11eb62008-06-04 15:04:05 -04006186 set_rq_offline(rq);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006187 }
6188 spin_unlock_irqrestore(&rq->lock, flags);
6189 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006190#endif
6191 }
6192 return NOTIFY_OK;
6193}
6194
6195/* Register at highest priority so that task migration (migrate_all_tasks)
6196 * happens before everything else.
6197 */
Chandra Seetharaman26c21432006-06-27 02:54:10 -07006198static struct notifier_block __cpuinitdata migration_notifier = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07006199 .notifier_call = migration_call,
6200 .priority = 10
6201};
6202
Adrian Bunke6fe6642007-11-09 22:39:39 +01006203void __init migration_init(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006204{
6205 void *cpu = (void *)(long)smp_processor_id();
Akinobu Mita07dccf32006-09-29 02:00:22 -07006206 int err;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006207
6208 /* Start one for the boot CPU: */
Akinobu Mita07dccf32006-09-29 02:00:22 -07006209 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
6210 BUG_ON(err == NOTIFY_BAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006211 migration_call(&migration_notifier, CPU_ONLINE, cpu);
6212 register_cpu_notifier(&migration_notifier);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006213}
6214#endif
6215
6216#ifdef CONFIG_SMP
Christoph Lameter476f3532007-05-06 14:48:58 -07006217
Ingo Molnar3e9830d2007-10-15 17:00:13 +02006218#ifdef CONFIG_SCHED_DEBUG
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006219
Gautham R Shenoy099f98c2008-05-29 20:56:32 +05306220static inline const char *sd_level_to_string(enum sched_domain_level lvl)
6221{
6222 switch (lvl) {
6223 case SD_LV_NONE:
6224 return "NONE";
6225 case SD_LV_SIBLING:
6226 return "SIBLING";
6227 case SD_LV_MC:
6228 return "MC";
6229 case SD_LV_CPU:
6230 return "CPU";
6231 case SD_LV_NODE:
6232 return "NODE";
6233 case SD_LV_ALLNODES:
6234 return "ALLNODES";
6235 case SD_LV_MAX:
6236 return "MAX";
6237
6238 }
6239 return "MAX";
6240}
6241
Mike Travis7c16ec52008-04-04 18:11:11 -07006242static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level,
6243 cpumask_t *groupmask)
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006244{
6245 struct sched_group *group = sd->groups;
Mike Travis434d53b2008-04-04 18:11:04 -07006246 char str[256];
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006247
Mike Travis434d53b2008-04-04 18:11:04 -07006248 cpulist_scnprintf(str, sizeof(str), sd->span);
Mike Travis7c16ec52008-04-04 18:11:11 -07006249 cpus_clear(*groupmask);
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006250
6251 printk(KERN_DEBUG "%*s domain %d: ", level, "", level);
6252
6253 if (!(sd->flags & SD_LOAD_BALANCE)) {
6254 printk("does not load-balance\n");
6255 if (sd->parent)
6256 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
6257 " has parent");
6258 return -1;
6259 }
6260
Gautham R Shenoy099f98c2008-05-29 20:56:32 +05306261 printk(KERN_CONT "span %s level %s\n",
6262 str, sd_level_to_string(sd->level));
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006263
6264 if (!cpu_isset(cpu, sd->span)) {
6265 printk(KERN_ERR "ERROR: domain->span does not contain "
6266 "CPU%d\n", cpu);
6267 }
6268 if (!cpu_isset(cpu, group->cpumask)) {
6269 printk(KERN_ERR "ERROR: domain->groups does not contain"
6270 " CPU%d\n", cpu);
6271 }
6272
6273 printk(KERN_DEBUG "%*s groups:", level + 1, "");
6274 do {
6275 if (!group) {
6276 printk("\n");
6277 printk(KERN_ERR "ERROR: group is NULL\n");
6278 break;
6279 }
6280
6281 if (!group->__cpu_power) {
6282 printk(KERN_CONT "\n");
6283 printk(KERN_ERR "ERROR: domain->cpu_power not "
6284 "set\n");
6285 break;
6286 }
6287
6288 if (!cpus_weight(group->cpumask)) {
6289 printk(KERN_CONT "\n");
6290 printk(KERN_ERR "ERROR: empty group\n");
6291 break;
6292 }
6293
Mike Travis7c16ec52008-04-04 18:11:11 -07006294 if (cpus_intersects(*groupmask, group->cpumask)) {
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006295 printk(KERN_CONT "\n");
6296 printk(KERN_ERR "ERROR: repeated CPUs\n");
6297 break;
6298 }
6299
Mike Travis7c16ec52008-04-04 18:11:11 -07006300 cpus_or(*groupmask, *groupmask, group->cpumask);
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006301
Mike Travis434d53b2008-04-04 18:11:04 -07006302 cpulist_scnprintf(str, sizeof(str), group->cpumask);
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006303 printk(KERN_CONT " %s", str);
6304
6305 group = group->next;
6306 } while (group != sd->groups);
6307 printk(KERN_CONT "\n");
6308
Mike Travis7c16ec52008-04-04 18:11:11 -07006309 if (!cpus_equal(sd->span, *groupmask))
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006310 printk(KERN_ERR "ERROR: groups don't span domain->span\n");
6311
Mike Travis7c16ec52008-04-04 18:11:11 -07006312 if (sd->parent && !cpus_subset(*groupmask, sd->parent->span))
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006313 printk(KERN_ERR "ERROR: parent span is not a superset "
6314 "of domain->span\n");
6315 return 0;
6316}
6317
Linus Torvalds1da177e2005-04-16 15:20:36 -07006318static void sched_domain_debug(struct sched_domain *sd, int cpu)
6319{
Mike Travis7c16ec52008-04-04 18:11:11 -07006320 cpumask_t *groupmask;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006321 int level = 0;
6322
Nick Piggin41c7ce92005-06-25 14:57:24 -07006323 if (!sd) {
6324 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
6325 return;
6326 }
6327
Linus Torvalds1da177e2005-04-16 15:20:36 -07006328 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
6329
Mike Travis7c16ec52008-04-04 18:11:11 -07006330 groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
6331 if (!groupmask) {
6332 printk(KERN_DEBUG "Cannot load-balance (out of memory)\n");
6333 return;
6334 }
6335
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006336 for (;;) {
Mike Travis7c16ec52008-04-04 18:11:11 -07006337 if (sched_domain_debug_one(sd, cpu, level, groupmask))
Linus Torvalds1da177e2005-04-16 15:20:36 -07006338 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006339 level++;
6340 sd = sd->parent;
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08006341 if (!sd)
Ingo Molnar4dcf6af2007-10-24 18:23:48 +02006342 break;
6343 }
Mike Travis7c16ec52008-04-04 18:11:11 -07006344 kfree(groupmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006345}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006346#else /* !CONFIG_SCHED_DEBUG */
Ingo Molnar48f24c42006-07-03 00:25:40 -07006347# define sched_domain_debug(sd, cpu) do { } while (0)
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006348#endif /* CONFIG_SCHED_DEBUG */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006349
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006350static int sd_degenerate(struct sched_domain *sd)
Suresh Siddha245af2c2005-06-25 14:57:25 -07006351{
6352 if (cpus_weight(sd->span) == 1)
6353 return 1;
6354
6355 /* Following flags need at least 2 groups */
6356 if (sd->flags & (SD_LOAD_BALANCE |
6357 SD_BALANCE_NEWIDLE |
6358 SD_BALANCE_FORK |
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006359 SD_BALANCE_EXEC |
6360 SD_SHARE_CPUPOWER |
6361 SD_SHARE_PKG_RESOURCES)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07006362 if (sd->groups != sd->groups->next)
6363 return 0;
6364 }
6365
6366 /* Following flags don't use groups */
6367 if (sd->flags & (SD_WAKE_IDLE |
6368 SD_WAKE_AFFINE |
6369 SD_WAKE_BALANCE))
6370 return 0;
6371
6372 return 1;
6373}
6374
Ingo Molnar48f24c42006-07-03 00:25:40 -07006375static int
6376sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
Suresh Siddha245af2c2005-06-25 14:57:25 -07006377{
6378 unsigned long cflags = sd->flags, pflags = parent->flags;
6379
6380 if (sd_degenerate(parent))
6381 return 1;
6382
6383 if (!cpus_equal(sd->span, parent->span))
6384 return 0;
6385
6386 /* Does parent contain flags not in child? */
6387 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
6388 if (cflags & SD_WAKE_AFFINE)
6389 pflags &= ~SD_WAKE_BALANCE;
6390 /* Flags needing groups don't count if only 1 group in parent */
6391 if (parent->groups == parent->groups->next) {
6392 pflags &= ~(SD_LOAD_BALANCE |
6393 SD_BALANCE_NEWIDLE |
6394 SD_BALANCE_FORK |
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006395 SD_BALANCE_EXEC |
6396 SD_SHARE_CPUPOWER |
6397 SD_SHARE_PKG_RESOURCES);
Suresh Siddha245af2c2005-06-25 14:57:25 -07006398 }
6399 if (~cflags & pflags)
6400 return 0;
6401
6402 return 1;
6403}
6404
Gregory Haskins57d885f2008-01-25 21:08:18 +01006405static void rq_attach_root(struct rq *rq, struct root_domain *rd)
6406{
6407 unsigned long flags;
Gregory Haskins57d885f2008-01-25 21:08:18 +01006408
6409 spin_lock_irqsave(&rq->lock, flags);
6410
6411 if (rq->rd) {
6412 struct root_domain *old_rd = rq->rd;
6413
Gregory Haskins1f11eb62008-06-04 15:04:05 -04006414 if (cpu_isset(rq->cpu, old_rd->online))
6415 set_rq_offline(rq);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006416
Gregory Haskinsdc938522008-01-25 21:08:26 +01006417 cpu_clear(rq->cpu, old_rd->span);
Gregory Haskinsdc938522008-01-25 21:08:26 +01006418
Gregory Haskins57d885f2008-01-25 21:08:18 +01006419 if (atomic_dec_and_test(&old_rd->refcount))
6420 kfree(old_rd);
6421 }
6422
6423 atomic_inc(&rd->refcount);
6424 rq->rd = rd;
6425
Gregory Haskinsdc938522008-01-25 21:08:26 +01006426 cpu_set(rq->cpu, rd->span);
Gregory Haskins1f94ef52008-03-10 16:52:41 -04006427 if (cpu_isset(rq->cpu, cpu_online_map))
Gregory Haskins1f11eb62008-06-04 15:04:05 -04006428 set_rq_online(rq);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006429
6430 spin_unlock_irqrestore(&rq->lock, flags);
6431}
6432
Gregory Haskinsdc938522008-01-25 21:08:26 +01006433static void init_rootdomain(struct root_domain *rd)
Gregory Haskins57d885f2008-01-25 21:08:18 +01006434{
6435 memset(rd, 0, sizeof(*rd));
6436
Gregory Haskinsdc938522008-01-25 21:08:26 +01006437 cpus_clear(rd->span);
6438 cpus_clear(rd->online);
Gregory Haskins6e0534f2008-05-12 21:21:01 +02006439
6440 cpupri_init(&rd->cpupri);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006441}
6442
6443static void init_defrootdomain(void)
6444{
Gregory Haskinsdc938522008-01-25 21:08:26 +01006445 init_rootdomain(&def_root_domain);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006446 atomic_set(&def_root_domain.refcount, 1);
6447}
6448
Gregory Haskinsdc938522008-01-25 21:08:26 +01006449static struct root_domain *alloc_rootdomain(void)
Gregory Haskins57d885f2008-01-25 21:08:18 +01006450{
6451 struct root_domain *rd;
6452
6453 rd = kmalloc(sizeof(*rd), GFP_KERNEL);
6454 if (!rd)
6455 return NULL;
6456
Gregory Haskinsdc938522008-01-25 21:08:26 +01006457 init_rootdomain(rd);
Gregory Haskins57d885f2008-01-25 21:08:18 +01006458
6459 return rd;
6460}
6461
Linus Torvalds1da177e2005-04-16 15:20:36 -07006462/*
Ingo Molnar0eab9142008-01-25 21:08:19 +01006463 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
Linus Torvalds1da177e2005-04-16 15:20:36 -07006464 * hold the hotplug lock.
6465 */
Ingo Molnar0eab9142008-01-25 21:08:19 +01006466static void
6467cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006468{
Ingo Molnar70b97a72006-07-03 00:25:42 -07006469 struct rq *rq = cpu_rq(cpu);
Suresh Siddha245af2c2005-06-25 14:57:25 -07006470 struct sched_domain *tmp;
6471
6472 /* Remove the sched domains which do not contribute to scheduling. */
6473 for (tmp = sd; tmp; tmp = tmp->parent) {
6474 struct sched_domain *parent = tmp->parent;
6475 if (!parent)
6476 break;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006477 if (sd_parent_degenerate(tmp, parent)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07006478 tmp->parent = parent->parent;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006479 if (parent->parent)
6480 parent->parent->child = tmp;
6481 }
Suresh Siddha245af2c2005-06-25 14:57:25 -07006482 }
6483
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006484 if (sd && sd_degenerate(sd)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07006485 sd = sd->parent;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006486 if (sd)
6487 sd->child = NULL;
6488 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07006489
6490 sched_domain_debug(sd, cpu);
6491
Gregory Haskins57d885f2008-01-25 21:08:18 +01006492 rq_attach_root(rq, rd);
Nick Piggin674311d2005-06-25 14:57:27 -07006493 rcu_assign_pointer(rq->sd, sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006494}
6495
6496/* cpus with isolated domains */
Tim Chen67af63a2006-12-22 01:07:50 -08006497static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006498
6499/* Setup the mask of cpus configured for isolated domains */
6500static int __init isolated_cpu_setup(char *str)
6501{
6502 int ints[NR_CPUS], i;
6503
6504 str = get_options(str, ARRAY_SIZE(ints), ints);
6505 cpus_clear(cpu_isolated_map);
6506 for (i = 1; i <= ints[0]; i++)
6507 if (ints[i] < NR_CPUS)
6508 cpu_set(ints[i], cpu_isolated_map);
6509 return 1;
6510}
6511
Ingo Molnar8927f492007-10-15 17:00:13 +02006512__setup("isolcpus=", isolated_cpu_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006513
6514/*
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006515 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
6516 * to a function which identifies what group(along with sched group) a CPU
6517 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
6518 * (due to the fact that we keep track of groups covered with a cpumask_t).
Linus Torvalds1da177e2005-04-16 15:20:36 -07006519 *
6520 * init_sched_build_groups will build a circular linked list of the groups
6521 * covered by the given span, and will set each group's ->cpumask correctly,
6522 * and ->cpu_power to 0.
6523 */
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006524static void
Mike Travis7c16ec52008-04-04 18:11:11 -07006525init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map,
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006526 int (*group_fn)(int cpu, const cpumask_t *cpu_map,
Mike Travis7c16ec52008-04-04 18:11:11 -07006527 struct sched_group **sg,
6528 cpumask_t *tmpmask),
6529 cpumask_t *covered, cpumask_t *tmpmask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006530{
6531 struct sched_group *first = NULL, *last = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006532 int i;
6533
Mike Travis7c16ec52008-04-04 18:11:11 -07006534 cpus_clear(*covered);
6535
6536 for_each_cpu_mask(i, *span) {
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006537 struct sched_group *sg;
Mike Travis7c16ec52008-04-04 18:11:11 -07006538 int group = group_fn(i, cpu_map, &sg, tmpmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006539 int j;
6540
Mike Travis7c16ec52008-04-04 18:11:11 -07006541 if (cpu_isset(i, *covered))
Linus Torvalds1da177e2005-04-16 15:20:36 -07006542 continue;
6543
Mike Travis7c16ec52008-04-04 18:11:11 -07006544 cpus_clear(sg->cpumask);
Eric Dumazet5517d862007-05-08 00:32:57 -07006545 sg->__cpu_power = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006546
Mike Travis7c16ec52008-04-04 18:11:11 -07006547 for_each_cpu_mask(j, *span) {
6548 if (group_fn(j, cpu_map, NULL, tmpmask) != group)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006549 continue;
6550
Mike Travis7c16ec52008-04-04 18:11:11 -07006551 cpu_set(j, *covered);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006552 cpu_set(j, sg->cpumask);
6553 }
6554 if (!first)
6555 first = sg;
6556 if (last)
6557 last->next = sg;
6558 last = sg;
6559 }
6560 last->next = first;
6561}
6562
John Hawkes9c1cfda2005-09-06 15:18:14 -07006563#define SD_NODES_PER_DOMAIN 16
Linus Torvalds1da177e2005-04-16 15:20:36 -07006564
John Hawkes9c1cfda2005-09-06 15:18:14 -07006565#ifdef CONFIG_NUMA
akpm@osdl.org198e2f12006-01-12 01:05:30 -08006566
John Hawkes9c1cfda2005-09-06 15:18:14 -07006567/**
6568 * find_next_best_node - find the next node to include in a sched_domain
6569 * @node: node whose sched_domain we're building
6570 * @used_nodes: nodes already in the sched_domain
6571 *
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006572 * Find the next node to include in a given scheduling domain. Simply
John Hawkes9c1cfda2005-09-06 15:18:14 -07006573 * finds the closest node not already in the @used_nodes map.
6574 *
6575 * Should use nodemask_t.
6576 */
Mike Travisc5f59f02008-04-04 18:11:10 -07006577static int find_next_best_node(int node, nodemask_t *used_nodes)
John Hawkes9c1cfda2005-09-06 15:18:14 -07006578{
6579 int i, n, val, min_val, best_node = 0;
6580
6581 min_val = INT_MAX;
6582
6583 for (i = 0; i < MAX_NUMNODES; i++) {
6584 /* Start at @node */
6585 n = (node + i) % MAX_NUMNODES;
6586
6587 if (!nr_cpus_node(n))
6588 continue;
6589
6590 /* Skip already used nodes */
Mike Travisc5f59f02008-04-04 18:11:10 -07006591 if (node_isset(n, *used_nodes))
John Hawkes9c1cfda2005-09-06 15:18:14 -07006592 continue;
6593
6594 /* Simple min distance search */
6595 val = node_distance(node, n);
6596
6597 if (val < min_val) {
6598 min_val = val;
6599 best_node = n;
6600 }
6601 }
6602
Mike Travisc5f59f02008-04-04 18:11:10 -07006603 node_set(best_node, *used_nodes);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006604 return best_node;
6605}
6606
6607/**
6608 * sched_domain_node_span - get a cpumask for a node's sched_domain
6609 * @node: node whose cpumask we're constructing
Randy Dunlap73486722008-04-22 10:07:22 -07006610 * @span: resulting cpumask
John Hawkes9c1cfda2005-09-06 15:18:14 -07006611 *
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006612 * Given a node, construct a good cpumask for its sched_domain to span. It
John Hawkes9c1cfda2005-09-06 15:18:14 -07006613 * should be one that prevents unnecessary balancing, but also spreads tasks
6614 * out optimally.
6615 */
Mike Travis4bdbaad32008-04-15 16:35:52 -07006616static void sched_domain_node_span(int node, cpumask_t *span)
John Hawkes9c1cfda2005-09-06 15:18:14 -07006617{
Mike Travisc5f59f02008-04-04 18:11:10 -07006618 nodemask_t used_nodes;
Mike Travisc5f59f02008-04-04 18:11:10 -07006619 node_to_cpumask_ptr(nodemask, node);
Ingo Molnar48f24c42006-07-03 00:25:40 -07006620 int i;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006621
Mike Travis4bdbaad32008-04-15 16:35:52 -07006622 cpus_clear(*span);
Mike Travisc5f59f02008-04-04 18:11:10 -07006623 nodes_clear(used_nodes);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006624
Mike Travis4bdbaad32008-04-15 16:35:52 -07006625 cpus_or(*span, *span, *nodemask);
Mike Travisc5f59f02008-04-04 18:11:10 -07006626 node_set(node, used_nodes);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006627
6628 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
Mike Travisc5f59f02008-04-04 18:11:10 -07006629 int next_node = find_next_best_node(node, &used_nodes);
Ingo Molnar48f24c42006-07-03 00:25:40 -07006630
Mike Travisc5f59f02008-04-04 18:11:10 -07006631 node_to_cpumask_ptr_next(nodemask, next_node);
Mike Travis4bdbaad32008-04-15 16:35:52 -07006632 cpus_or(*span, *span, *nodemask);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006633 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07006634}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006635#endif /* CONFIG_NUMA */
John Hawkes9c1cfda2005-09-06 15:18:14 -07006636
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006637int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006638
John Hawkes9c1cfda2005-09-06 15:18:14 -07006639/*
Ingo Molnar48f24c42006-07-03 00:25:40 -07006640 * SMT sched-domains:
John Hawkes9c1cfda2005-09-06 15:18:14 -07006641 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006642#ifdef CONFIG_SCHED_SMT
6643static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006644static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
Ingo Molnar48f24c42006-07-03 00:25:40 -07006645
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006646static int
Mike Travis7c16ec52008-04-04 18:11:11 -07006647cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6648 cpumask_t *unused)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006649{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006650 if (sg)
6651 *sg = &per_cpu(sched_group_cpus, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006652 return cpu;
6653}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006654#endif /* CONFIG_SCHED_SMT */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006655
Ingo Molnar48f24c42006-07-03 00:25:40 -07006656/*
6657 * multi-core sched-domains:
6658 */
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006659#ifdef CONFIG_SCHED_MC
6660static DEFINE_PER_CPU(struct sched_domain, core_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006661static DEFINE_PER_CPU(struct sched_group, sched_group_core);
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006662#endif /* CONFIG_SCHED_MC */
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006663
6664#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006665static int
Mike Travis7c16ec52008-04-04 18:11:11 -07006666cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6667 cpumask_t *mask)
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006668{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006669 int group;
Mike Travis7c16ec52008-04-04 18:11:11 -07006670
6671 *mask = per_cpu(cpu_sibling_map, cpu);
6672 cpus_and(*mask, *mask, *cpu_map);
6673 group = first_cpu(*mask);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006674 if (sg)
6675 *sg = &per_cpu(sched_group_core, group);
6676 return group;
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006677}
6678#elif defined(CONFIG_SCHED_MC)
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006679static int
Mike Travis7c16ec52008-04-04 18:11:11 -07006680cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6681 cpumask_t *unused)
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006682{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006683 if (sg)
6684 *sg = &per_cpu(sched_group_core, cpu);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006685 return cpu;
6686}
6687#endif
6688
Linus Torvalds1da177e2005-04-16 15:20:36 -07006689static DEFINE_PER_CPU(struct sched_domain, phys_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006690static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
Ingo Molnar48f24c42006-07-03 00:25:40 -07006691
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006692static int
Mike Travis7c16ec52008-04-04 18:11:11 -07006693cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg,
6694 cpumask_t *mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006695{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006696 int group;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006697#ifdef CONFIG_SCHED_MC
Mike Travis7c16ec52008-04-04 18:11:11 -07006698 *mask = cpu_coregroup_map(cpu);
6699 cpus_and(*mask, *mask, *cpu_map);
6700 group = first_cpu(*mask);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006701#elif defined(CONFIG_SCHED_SMT)
Mike Travis7c16ec52008-04-04 18:11:11 -07006702 *mask = per_cpu(cpu_sibling_map, cpu);
6703 cpus_and(*mask, *mask, *cpu_map);
6704 group = first_cpu(*mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006705#else
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006706 group = cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006707#endif
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006708 if (sg)
6709 *sg = &per_cpu(sched_group_phys, group);
6710 return group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006711}
6712
6713#ifdef CONFIG_NUMA
John Hawkes9c1cfda2005-09-06 15:18:14 -07006714/*
6715 * The init_sched_build_groups can't handle what we want to do with node
6716 * groups, so roll our own. Now each node has its own list of groups which
6717 * gets dynamically allocated.
6718 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006719static DEFINE_PER_CPU(struct sched_domain, node_domains);
Mike Travis434d53b2008-04-04 18:11:04 -07006720static struct sched_group ***sched_group_nodes_bycpu;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006721
6722static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006723static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006724
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006725static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
Mike Travis7c16ec52008-04-04 18:11:11 -07006726 struct sched_group **sg, cpumask_t *nodemask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006727{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006728 int group;
6729
Mike Travis7c16ec52008-04-04 18:11:11 -07006730 *nodemask = node_to_cpumask(cpu_to_node(cpu));
6731 cpus_and(*nodemask, *nodemask, *cpu_map);
6732 group = first_cpu(*nodemask);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006733
6734 if (sg)
6735 *sg = &per_cpu(sched_group_allnodes, group);
6736 return group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006737}
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006738
Siddha, Suresh B08069032006-03-27 01:15:23 -08006739static void init_numa_sched_groups_power(struct sched_group *group_head)
6740{
6741 struct sched_group *sg = group_head;
6742 int j;
6743
6744 if (!sg)
6745 return;
Andi Kleen3a5c3592007-10-15 17:00:14 +02006746 do {
6747 for_each_cpu_mask(j, sg->cpumask) {
6748 struct sched_domain *sd;
Siddha, Suresh B08069032006-03-27 01:15:23 -08006749
Andi Kleen3a5c3592007-10-15 17:00:14 +02006750 sd = &per_cpu(phys_domains, j);
6751 if (j != first_cpu(sd->groups->cpumask)) {
6752 /*
6753 * Only add "power" once for each
6754 * physical package.
6755 */
6756 continue;
6757 }
6758
6759 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
Siddha, Suresh B08069032006-03-27 01:15:23 -08006760 }
Andi Kleen3a5c3592007-10-15 17:00:14 +02006761 sg = sg->next;
6762 } while (sg != group_head);
Siddha, Suresh B08069032006-03-27 01:15:23 -08006763}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006764#endif /* CONFIG_NUMA */
Linus Torvalds1da177e2005-04-16 15:20:36 -07006765
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006766#ifdef CONFIG_NUMA
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006767/* Free memory allocated for various sched_group structures */
Mike Travis7c16ec52008-04-04 18:11:11 -07006768static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006769{
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006770 int cpu, i;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006771
6772 for_each_cpu_mask(cpu, *cpu_map) {
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006773 struct sched_group **sched_group_nodes
6774 = sched_group_nodes_bycpu[cpu];
6775
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006776 if (!sched_group_nodes)
6777 continue;
6778
6779 for (i = 0; i < MAX_NUMNODES; i++) {
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006780 struct sched_group *oldsg, *sg = sched_group_nodes[i];
6781
Mike Travis7c16ec52008-04-04 18:11:11 -07006782 *nodemask = node_to_cpumask(i);
6783 cpus_and(*nodemask, *nodemask, *cpu_map);
6784 if (cpus_empty(*nodemask))
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006785 continue;
6786
6787 if (sg == NULL)
6788 continue;
6789 sg = sg->next;
6790next_sg:
6791 oldsg = sg;
6792 sg = sg->next;
6793 kfree(oldsg);
6794 if (oldsg != sched_group_nodes[i])
6795 goto next_sg;
6796 }
6797 kfree(sched_group_nodes);
6798 sched_group_nodes_bycpu[cpu] = NULL;
6799 }
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006800}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006801#else /* !CONFIG_NUMA */
Mike Travis7c16ec52008-04-04 18:11:11 -07006802static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask)
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006803{
6804}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02006805#endif /* CONFIG_NUMA */
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006806
Linus Torvalds1da177e2005-04-16 15:20:36 -07006807/*
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006808 * Initialize sched groups cpu_power.
6809 *
6810 * cpu_power indicates the capacity of sched group, which is used while
6811 * distributing the load between different sched groups in a sched domain.
6812 * Typically cpu_power for all the groups in a sched domain will be same unless
6813 * there are asymmetries in the topology. If there are asymmetries, group
6814 * having more cpu_power will pickup more load compared to the group having
6815 * less cpu_power.
6816 *
6817 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6818 * the maximum number of tasks a group can handle in the presence of other idle
6819 * or lightly loaded groups in the same sched domain.
6820 */
6821static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6822{
6823 struct sched_domain *child;
6824 struct sched_group *group;
6825
6826 WARN_ON(!sd || !sd->groups);
6827
6828 if (cpu != first_cpu(sd->groups->cpumask))
6829 return;
6830
6831 child = sd->child;
6832
Eric Dumazet5517d862007-05-08 00:32:57 -07006833 sd->groups->__cpu_power = 0;
6834
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006835 /*
6836 * For perf policy, if the groups in child domain share resources
6837 * (for example cores sharing some portions of the cache hierarchy
6838 * or SMT), then set this domain groups cpu_power such that each group
6839 * can handle only one task, when there are other idle groups in the
6840 * same sched domain.
6841 */
6842 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
6843 (child->flags &
6844 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
Eric Dumazet5517d862007-05-08 00:32:57 -07006845 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006846 return;
6847 }
6848
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006849 /*
6850 * add cpu_power of each child group to this groups cpu_power
6851 */
6852 group = child->groups;
6853 do {
Eric Dumazet5517d862007-05-08 00:32:57 -07006854 sg_inc_cpu_power(sd->groups, group->__cpu_power);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006855 group = group->next;
6856 } while (group != child->groups);
6857}
6858
6859/*
Mike Travis7c16ec52008-04-04 18:11:11 -07006860 * Initializers for schedule domains
6861 * Non-inlined to reduce accumulated stack pressure in build_sched_domains()
6862 */
6863
6864#define SD_INIT(sd, type) sd_init_##type(sd)
6865#define SD_INIT_FUNC(type) \
6866static noinline void sd_init_##type(struct sched_domain *sd) \
6867{ \
6868 memset(sd, 0, sizeof(*sd)); \
6869 *sd = SD_##type##_INIT; \
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09006870 sd->level = SD_LV_##type; \
Mike Travis7c16ec52008-04-04 18:11:11 -07006871}
6872
6873SD_INIT_FUNC(CPU)
6874#ifdef CONFIG_NUMA
6875 SD_INIT_FUNC(ALLNODES)
6876 SD_INIT_FUNC(NODE)
6877#endif
6878#ifdef CONFIG_SCHED_SMT
6879 SD_INIT_FUNC(SIBLING)
6880#endif
6881#ifdef CONFIG_SCHED_MC
6882 SD_INIT_FUNC(MC)
6883#endif
6884
6885/*
6886 * To minimize stack usage kmalloc room for cpumasks and share the
6887 * space as the usage in build_sched_domains() dictates. Used only
6888 * if the amount of space is significant.
6889 */
6890struct allmasks {
6891 cpumask_t tmpmask; /* make this one first */
6892 union {
6893 cpumask_t nodemask;
6894 cpumask_t this_sibling_map;
6895 cpumask_t this_core_map;
6896 };
6897 cpumask_t send_covered;
6898
6899#ifdef CONFIG_NUMA
6900 cpumask_t domainspan;
6901 cpumask_t covered;
6902 cpumask_t notcovered;
6903#endif
6904};
6905
6906#if NR_CPUS > 128
6907#define SCHED_CPUMASK_ALLOC 1
6908#define SCHED_CPUMASK_FREE(v) kfree(v)
6909#define SCHED_CPUMASK_DECLARE(v) struct allmasks *v
6910#else
6911#define SCHED_CPUMASK_ALLOC 0
6912#define SCHED_CPUMASK_FREE(v)
6913#define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v
6914#endif
6915
6916#define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \
6917 ((unsigned long)(a) + offsetof(struct allmasks, v))
6918
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09006919static int default_relax_domain_level = -1;
6920
6921static int __init setup_relax_domain_level(char *str)
6922{
6923 default_relax_domain_level = simple_strtoul(str, NULL, 0);
6924 return 1;
6925}
6926__setup("relax_domain_level=", setup_relax_domain_level);
6927
6928static void set_domain_attribute(struct sched_domain *sd,
6929 struct sched_domain_attr *attr)
6930{
6931 int request;
6932
6933 if (!attr || attr->relax_domain_level < 0) {
6934 if (default_relax_domain_level < 0)
6935 return;
6936 else
6937 request = default_relax_domain_level;
6938 } else
6939 request = attr->relax_domain_level;
6940 if (request < sd->level) {
6941 /* turn off idle balance on this domain */
6942 sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE);
6943 } else {
6944 /* turn on idle balance on this domain */
6945 sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE);
6946 }
6947}
6948
Mike Travis7c16ec52008-04-04 18:11:11 -07006949/*
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006950 * Build sched domains for a given set of cpus and attach the sched domains
6951 * to the individual cpus
Linus Torvalds1da177e2005-04-16 15:20:36 -07006952 */
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09006953static int __build_sched_domains(const cpumask_t *cpu_map,
6954 struct sched_domain_attr *attr)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006955{
6956 int i;
Gregory Haskins57d885f2008-01-25 21:08:18 +01006957 struct root_domain *rd;
Mike Travis7c16ec52008-04-04 18:11:11 -07006958 SCHED_CPUMASK_DECLARE(allmasks);
6959 cpumask_t *tmpmask;
John Hawkesd1b55132005-09-06 15:18:14 -07006960#ifdef CONFIG_NUMA
6961 struct sched_group **sched_group_nodes = NULL;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006962 int sd_allnodes = 0;
John Hawkesd1b55132005-09-06 15:18:14 -07006963
6964 /*
6965 * Allocate the per-node list of sched groups
6966 */
Milton Miller5cf9f062007-10-15 17:00:19 +02006967 sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *),
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01006968 GFP_KERNEL);
John Hawkesd1b55132005-09-06 15:18:14 -07006969 if (!sched_group_nodes) {
6970 printk(KERN_WARNING "Can not alloc sched group node list\n");
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006971 return -ENOMEM;
John Hawkesd1b55132005-09-06 15:18:14 -07006972 }
John Hawkesd1b55132005-09-06 15:18:14 -07006973#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07006974
Gregory Haskinsdc938522008-01-25 21:08:26 +01006975 rd = alloc_rootdomain();
Gregory Haskins57d885f2008-01-25 21:08:18 +01006976 if (!rd) {
6977 printk(KERN_WARNING "Cannot alloc root domain\n");
Mike Travis7c16ec52008-04-04 18:11:11 -07006978#ifdef CONFIG_NUMA
6979 kfree(sched_group_nodes);
6980#endif
Gregory Haskins57d885f2008-01-25 21:08:18 +01006981 return -ENOMEM;
6982 }
6983
Mike Travis7c16ec52008-04-04 18:11:11 -07006984#if SCHED_CPUMASK_ALLOC
6985 /* get space for all scratch cpumask variables */
6986 allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL);
6987 if (!allmasks) {
6988 printk(KERN_WARNING "Cannot alloc cpumask array\n");
6989 kfree(rd);
6990#ifdef CONFIG_NUMA
6991 kfree(sched_group_nodes);
6992#endif
6993 return -ENOMEM;
6994 }
6995#endif
6996 tmpmask = (cpumask_t *)allmasks;
6997
6998
6999#ifdef CONFIG_NUMA
7000 sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
7001#endif
7002
Linus Torvalds1da177e2005-04-16 15:20:36 -07007003 /*
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007004 * Set up domains for cpus specified by the cpu_map.
Linus Torvalds1da177e2005-04-16 15:20:36 -07007005 */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007006 for_each_cpu_mask(i, *cpu_map) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07007007 struct sched_domain *sd = NULL, *p;
Mike Travis7c16ec52008-04-04 18:11:11 -07007008 SCHED_CPUMASK_VAR(nodemask, allmasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007009
Mike Travis7c16ec52008-04-04 18:11:11 -07007010 *nodemask = node_to_cpumask(cpu_to_node(i));
7011 cpus_and(*nodemask, *nodemask, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007012
7013#ifdef CONFIG_NUMA
Ingo Molnardd41f592007-07-09 18:51:59 +02007014 if (cpus_weight(*cpu_map) >
Mike Travis7c16ec52008-04-04 18:11:11 -07007015 SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) {
John Hawkes9c1cfda2005-09-06 15:18:14 -07007016 sd = &per_cpu(allnodes_domains, i);
Mike Travis7c16ec52008-04-04 18:11:11 -07007017 SD_INIT(sd, ALLNODES);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007018 set_domain_attribute(sd, attr);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007019 sd->span = *cpu_map;
Mike Travis7c16ec52008-04-04 18:11:11 -07007020 cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007021 p = sd;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08007022 sd_allnodes = 1;
John Hawkes9c1cfda2005-09-06 15:18:14 -07007023 } else
7024 p = NULL;
7025
Linus Torvalds1da177e2005-04-16 15:20:36 -07007026 sd = &per_cpu(node_domains, i);
Mike Travis7c16ec52008-04-04 18:11:11 -07007027 SD_INIT(sd, NODE);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007028 set_domain_attribute(sd, attr);
Mike Travis4bdbaad32008-04-15 16:35:52 -07007029 sched_domain_node_span(cpu_to_node(i), &sd->span);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007030 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07007031 if (p)
7032 p->child = sd;
John Hawkes9c1cfda2005-09-06 15:18:14 -07007033 cpus_and(sd->span, sd->span, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007034#endif
7035
7036 p = sd;
7037 sd = &per_cpu(phys_domains, i);
Mike Travis7c16ec52008-04-04 18:11:11 -07007038 SD_INIT(sd, CPU);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007039 set_domain_attribute(sd, attr);
Mike Travis7c16ec52008-04-04 18:11:11 -07007040 sd->span = *nodemask;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007041 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07007042 if (p)
7043 p->child = sd;
Mike Travis7c16ec52008-04-04 18:11:11 -07007044 cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007045
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007046#ifdef CONFIG_SCHED_MC
7047 p = sd;
7048 sd = &per_cpu(core_domains, i);
Mike Travis7c16ec52008-04-04 18:11:11 -07007049 SD_INIT(sd, MC);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007050 set_domain_attribute(sd, attr);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007051 sd->span = cpu_coregroup_map(i);
7052 cpus_and(sd->span, sd->span, *cpu_map);
7053 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07007054 p->child = sd;
Mike Travis7c16ec52008-04-04 18:11:11 -07007055 cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007056#endif
7057
Linus Torvalds1da177e2005-04-16 15:20:36 -07007058#ifdef CONFIG_SCHED_SMT
7059 p = sd;
7060 sd = &per_cpu(cpu_domains, i);
Mike Travis7c16ec52008-04-04 18:11:11 -07007061 SD_INIT(sd, SIBLING);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007062 set_domain_attribute(sd, attr);
Mike Travisd5a74302007-10-16 01:24:05 -07007063 sd->span = per_cpu(cpu_sibling_map, i);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007064 cpus_and(sd->span, sd->span, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007065 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07007066 p->child = sd;
Mike Travis7c16ec52008-04-04 18:11:11 -07007067 cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007068#endif
7069 }
7070
7071#ifdef CONFIG_SCHED_SMT
7072 /* Set up CPU (sibling) groups */
John Hawkes9c1cfda2005-09-06 15:18:14 -07007073 for_each_cpu_mask(i, *cpu_map) {
Mike Travis7c16ec52008-04-04 18:11:11 -07007074 SCHED_CPUMASK_VAR(this_sibling_map, allmasks);
7075 SCHED_CPUMASK_VAR(send_covered, allmasks);
7076
7077 *this_sibling_map = per_cpu(cpu_sibling_map, i);
7078 cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map);
7079 if (i != first_cpu(*this_sibling_map))
Linus Torvalds1da177e2005-04-16 15:20:36 -07007080 continue;
7081
Ingo Molnardd41f592007-07-09 18:51:59 +02007082 init_sched_build_groups(this_sibling_map, cpu_map,
Mike Travis7c16ec52008-04-04 18:11:11 -07007083 &cpu_to_cpu_group,
7084 send_covered, tmpmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007085 }
7086#endif
7087
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007088#ifdef CONFIG_SCHED_MC
7089 /* Set up multi-core groups */
7090 for_each_cpu_mask(i, *cpu_map) {
Mike Travis7c16ec52008-04-04 18:11:11 -07007091 SCHED_CPUMASK_VAR(this_core_map, allmasks);
7092 SCHED_CPUMASK_VAR(send_covered, allmasks);
7093
7094 *this_core_map = cpu_coregroup_map(i);
7095 cpus_and(*this_core_map, *this_core_map, *cpu_map);
7096 if (i != first_cpu(*this_core_map))
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007097 continue;
Mike Travis7c16ec52008-04-04 18:11:11 -07007098
Ingo Molnardd41f592007-07-09 18:51:59 +02007099 init_sched_build_groups(this_core_map, cpu_map,
Mike Travis7c16ec52008-04-04 18:11:11 -07007100 &cpu_to_core_group,
7101 send_covered, tmpmask);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007102 }
7103#endif
7104
Linus Torvalds1da177e2005-04-16 15:20:36 -07007105 /* Set up physical groups */
7106 for (i = 0; i < MAX_NUMNODES; i++) {
Mike Travis7c16ec52008-04-04 18:11:11 -07007107 SCHED_CPUMASK_VAR(nodemask, allmasks);
7108 SCHED_CPUMASK_VAR(send_covered, allmasks);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007109
Mike Travis7c16ec52008-04-04 18:11:11 -07007110 *nodemask = node_to_cpumask(i);
7111 cpus_and(*nodemask, *nodemask, *cpu_map);
7112 if (cpus_empty(*nodemask))
Linus Torvalds1da177e2005-04-16 15:20:36 -07007113 continue;
7114
Mike Travis7c16ec52008-04-04 18:11:11 -07007115 init_sched_build_groups(nodemask, cpu_map,
7116 &cpu_to_phys_group,
7117 send_covered, tmpmask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007118 }
7119
7120#ifdef CONFIG_NUMA
7121 /* Set up node groups */
Mike Travis7c16ec52008-04-04 18:11:11 -07007122 if (sd_allnodes) {
7123 SCHED_CPUMASK_VAR(send_covered, allmasks);
7124
7125 init_sched_build_groups(cpu_map, cpu_map,
7126 &cpu_to_allnodes_group,
7127 send_covered, tmpmask);
7128 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07007129
7130 for (i = 0; i < MAX_NUMNODES; i++) {
7131 /* Set up node groups */
7132 struct sched_group *sg, *prev;
Mike Travis7c16ec52008-04-04 18:11:11 -07007133 SCHED_CPUMASK_VAR(nodemask, allmasks);
7134 SCHED_CPUMASK_VAR(domainspan, allmasks);
7135 SCHED_CPUMASK_VAR(covered, allmasks);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007136 int j;
7137
Mike Travis7c16ec52008-04-04 18:11:11 -07007138 *nodemask = node_to_cpumask(i);
7139 cpus_clear(*covered);
7140
7141 cpus_and(*nodemask, *nodemask, *cpu_map);
7142 if (cpus_empty(*nodemask)) {
John Hawkesd1b55132005-09-06 15:18:14 -07007143 sched_group_nodes[i] = NULL;
John Hawkes9c1cfda2005-09-06 15:18:14 -07007144 continue;
John Hawkesd1b55132005-09-06 15:18:14 -07007145 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07007146
Mike Travis4bdbaad32008-04-15 16:35:52 -07007147 sched_domain_node_span(i, domainspan);
Mike Travis7c16ec52008-04-04 18:11:11 -07007148 cpus_and(*domainspan, *domainspan, *cpu_map);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007149
Srivatsa Vaddagiri15f0b672006-06-27 02:54:40 -07007150 sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007151 if (!sg) {
7152 printk(KERN_WARNING "Can not alloc domain group for "
7153 "node %d\n", i);
7154 goto error;
7155 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07007156 sched_group_nodes[i] = sg;
Mike Travis7c16ec52008-04-04 18:11:11 -07007157 for_each_cpu_mask(j, *nodemask) {
John Hawkes9c1cfda2005-09-06 15:18:14 -07007158 struct sched_domain *sd;
Ingo Molnar9761eea2007-07-09 18:52:00 +02007159
John Hawkes9c1cfda2005-09-06 15:18:14 -07007160 sd = &per_cpu(node_domains, j);
7161 sd->groups = sg;
John Hawkes9c1cfda2005-09-06 15:18:14 -07007162 }
Eric Dumazet5517d862007-05-08 00:32:57 -07007163 sg->__cpu_power = 0;
Mike Travis7c16ec52008-04-04 18:11:11 -07007164 sg->cpumask = *nodemask;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007165 sg->next = sg;
Mike Travis7c16ec52008-04-04 18:11:11 -07007166 cpus_or(*covered, *covered, *nodemask);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007167 prev = sg;
7168
7169 for (j = 0; j < MAX_NUMNODES; j++) {
Mike Travis7c16ec52008-04-04 18:11:11 -07007170 SCHED_CPUMASK_VAR(notcovered, allmasks);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007171 int n = (i + j) % MAX_NUMNODES;
Mike Travisc5f59f02008-04-04 18:11:10 -07007172 node_to_cpumask_ptr(pnodemask, n);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007173
Mike Travis7c16ec52008-04-04 18:11:11 -07007174 cpus_complement(*notcovered, *covered);
7175 cpus_and(*tmpmask, *notcovered, *cpu_map);
7176 cpus_and(*tmpmask, *tmpmask, *domainspan);
7177 if (cpus_empty(*tmpmask))
John Hawkes9c1cfda2005-09-06 15:18:14 -07007178 break;
7179
Mike Travis7c16ec52008-04-04 18:11:11 -07007180 cpus_and(*tmpmask, *tmpmask, *pnodemask);
7181 if (cpus_empty(*tmpmask))
John Hawkes9c1cfda2005-09-06 15:18:14 -07007182 continue;
7183
Srivatsa Vaddagiri15f0b672006-06-27 02:54:40 -07007184 sg = kmalloc_node(sizeof(struct sched_group),
7185 GFP_KERNEL, i);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007186 if (!sg) {
7187 printk(KERN_WARNING
7188 "Can not alloc domain group for node %d\n", j);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007189 goto error;
John Hawkes9c1cfda2005-09-06 15:18:14 -07007190 }
Eric Dumazet5517d862007-05-08 00:32:57 -07007191 sg->__cpu_power = 0;
Mike Travis7c16ec52008-04-04 18:11:11 -07007192 sg->cpumask = *tmpmask;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007193 sg->next = prev->next;
Mike Travis7c16ec52008-04-04 18:11:11 -07007194 cpus_or(*covered, *covered, *tmpmask);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007195 prev->next = sg;
7196 prev = sg;
7197 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07007198 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07007199#endif
7200
7201 /* Calculate CPU power for physical packages and nodes */
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007202#ifdef CONFIG_SCHED_SMT
7203 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02007204 struct sched_domain *sd = &per_cpu(cpu_domains, i);
7205
Siddha, Suresh B89c47102006-10-03 01:14:09 -07007206 init_sched_groups_power(i, sd);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007207 }
7208#endif
7209#ifdef CONFIG_SCHED_MC
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007210 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02007211 struct sched_domain *sd = &per_cpu(core_domains, i);
7212
Siddha, Suresh B89c47102006-10-03 01:14:09 -07007213 init_sched_groups_power(i, sd);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007214 }
7215#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07007216
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007217 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02007218 struct sched_domain *sd = &per_cpu(phys_domains, i);
7219
Siddha, Suresh B89c47102006-10-03 01:14:09 -07007220 init_sched_groups_power(i, sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007221 }
7222
John Hawkes9c1cfda2005-09-06 15:18:14 -07007223#ifdef CONFIG_NUMA
Siddha, Suresh B08069032006-03-27 01:15:23 -08007224 for (i = 0; i < MAX_NUMNODES; i++)
7225 init_numa_sched_groups_power(sched_group_nodes[i]);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007226
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08007227 if (sd_allnodes) {
7228 struct sched_group *sg;
Siddha, Suresh Bf712c0c2006-07-30 03:02:59 -07007229
Mike Travis7c16ec52008-04-04 18:11:11 -07007230 cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg,
7231 tmpmask);
Siddha, Suresh Bf712c0c2006-07-30 03:02:59 -07007232 init_numa_sched_groups_power(sg);
7233 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07007234#endif
7235
Linus Torvalds1da177e2005-04-16 15:20:36 -07007236 /* Attach the domains */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007237 for_each_cpu_mask(i, *cpu_map) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07007238 struct sched_domain *sd;
7239#ifdef CONFIG_SCHED_SMT
7240 sd = &per_cpu(cpu_domains, i);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08007241#elif defined(CONFIG_SCHED_MC)
7242 sd = &per_cpu(core_domains, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007243#else
7244 sd = &per_cpu(phys_domains, i);
7245#endif
Gregory Haskins57d885f2008-01-25 21:08:18 +01007246 cpu_attach_domain(sd, rd, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007247 }
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007248
Mike Travis7c16ec52008-04-04 18:11:11 -07007249 SCHED_CPUMASK_FREE((void *)allmasks);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007250 return 0;
7251
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07007252#ifdef CONFIG_NUMA
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007253error:
Mike Travis7c16ec52008-04-04 18:11:11 -07007254 free_sched_groups(cpu_map, tmpmask);
7255 SCHED_CPUMASK_FREE((void *)allmasks);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007256 return -ENOMEM;
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07007257#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07007258}
Paul Jackson029190c2007-10-18 23:40:20 -07007259
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007260static int build_sched_domains(const cpumask_t *cpu_map)
7261{
7262 return __build_sched_domains(cpu_map, NULL);
7263}
7264
Paul Jackson029190c2007-10-18 23:40:20 -07007265static cpumask_t *doms_cur; /* current sched domains */
7266static int ndoms_cur; /* number of sched domains in 'doms_cur' */
Ingo Molnar4285f5942008-05-16 17:47:14 +02007267static struct sched_domain_attr *dattr_cur;
7268 /* attribues of custom domains in 'doms_cur' */
Paul Jackson029190c2007-10-18 23:40:20 -07007269
7270/*
7271 * Special case: If a kmalloc of a doms_cur partition (array of
7272 * cpumask_t) fails, then fallback to a single sched domain,
7273 * as determined by the single cpumask_t fallback_doms.
7274 */
7275static cpumask_t fallback_doms;
7276
Heiko Carstens22e52b02008-03-12 18:31:59 +01007277void __attribute__((weak)) arch_update_cpu_topology(void)
7278{
7279}
7280
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007281/*
Max Krasnyansky5c8e1ed2008-05-29 11:17:01 -07007282 * Free current domain masks.
7283 * Called after all cpus are attached to NULL domain.
7284 */
7285static void free_sched_domains(void)
7286{
7287 ndoms_cur = 0;
7288 if (doms_cur != &fallback_doms)
7289 kfree(doms_cur);
7290 doms_cur = &fallback_doms;
7291}
7292
7293/*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01007294 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
Paul Jackson029190c2007-10-18 23:40:20 -07007295 * For now this just excludes isolated cpus, but could be used to
7296 * exclude other special cases in the future.
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007297 */
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07007298static int arch_init_sched_domains(const cpumask_t *cpu_map)
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007299{
Milton Miller73785472007-10-24 18:23:48 +02007300 int err;
7301
Heiko Carstens22e52b02008-03-12 18:31:59 +01007302 arch_update_cpu_topology();
Paul Jackson029190c2007-10-18 23:40:20 -07007303 ndoms_cur = 1;
7304 doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL);
7305 if (!doms_cur)
7306 doms_cur = &fallback_doms;
7307 cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007308 dattr_cur = NULL;
Milton Miller73785472007-10-24 18:23:48 +02007309 err = build_sched_domains(doms_cur);
Milton Miller6382bc92007-10-15 17:00:19 +02007310 register_sched_domain_sysctl();
Milton Miller73785472007-10-24 18:23:48 +02007311
7312 return err;
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007313}
7314
Mike Travis7c16ec52008-04-04 18:11:11 -07007315static void arch_destroy_sched_domains(const cpumask_t *cpu_map,
7316 cpumask_t *tmpmask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07007317{
Mike Travis7c16ec52008-04-04 18:11:11 -07007318 free_sched_groups(cpu_map, tmpmask);
John Hawkes9c1cfda2005-09-06 15:18:14 -07007319}
Linus Torvalds1da177e2005-04-16 15:20:36 -07007320
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007321/*
7322 * Detach sched domains from a group of cpus specified in cpu_map
7323 * These cpus will now be attached to the NULL domain
7324 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08007325static void detach_destroy_domains(const cpumask_t *cpu_map)
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007326{
Mike Travis7c16ec52008-04-04 18:11:11 -07007327 cpumask_t tmpmask;
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007328 int i;
7329
Milton Miller6382bc92007-10-15 17:00:19 +02007330 unregister_sched_domain_sysctl();
7331
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007332 for_each_cpu_mask(i, *cpu_map)
Gregory Haskins57d885f2008-01-25 21:08:18 +01007333 cpu_attach_domain(NULL, &def_root_domain, i);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007334 synchronize_sched();
Mike Travis7c16ec52008-04-04 18:11:11 -07007335 arch_destroy_sched_domains(cpu_map, &tmpmask);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007336}
7337
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007338/* handle null as "default" */
7339static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
7340 struct sched_domain_attr *new, int idx_new)
7341{
7342 struct sched_domain_attr tmp;
7343
7344 /* fast path */
7345 if (!new && !cur)
7346 return 1;
7347
7348 tmp = SD_ATTR_INIT;
7349 return !memcmp(cur ? (cur + idx_cur) : &tmp,
7350 new ? (new + idx_new) : &tmp,
7351 sizeof(struct sched_domain_attr));
7352}
7353
Paul Jackson029190c2007-10-18 23:40:20 -07007354/*
7355 * Partition sched domains as specified by the 'ndoms_new'
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01007356 * cpumasks in the array doms_new[] of cpumasks. This compares
Paul Jackson029190c2007-10-18 23:40:20 -07007357 * doms_new[] to the current sched domain partitioning, doms_cur[].
7358 * It destroys each deleted domain and builds each new domain.
7359 *
7360 * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'.
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01007361 * The masks don't intersect (don't overlap.) We should setup one
7362 * sched domain for each mask. CPUs not in any of the cpumasks will
7363 * not be load balanced. If the same cpumask appears both in the
Paul Jackson029190c2007-10-18 23:40:20 -07007364 * current 'doms_cur' domains and in the new 'doms_new', we can leave
7365 * it as it is.
7366 *
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01007367 * The passed in 'doms_new' should be kmalloc'd. This routine takes
7368 * ownership of it and will kfree it when done with it. If the caller
Paul Jackson029190c2007-10-18 23:40:20 -07007369 * failed the kmalloc call, then it can pass in doms_new == NULL,
7370 * and partition_sched_domains() will fallback to the single partition
7371 * 'fallback_doms'.
7372 *
7373 * Call with hotplug lock held
7374 */
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007375void partition_sched_domains(int ndoms_new, cpumask_t *doms_new,
7376 struct sched_domain_attr *dattr_new)
Paul Jackson029190c2007-10-18 23:40:20 -07007377{
7378 int i, j;
7379
Heiko Carstens712555e2008-04-28 11:33:07 +02007380 mutex_lock(&sched_domains_mutex);
Srivatsa Vaddagiria1835612008-01-25 21:08:00 +01007381
Milton Miller73785472007-10-24 18:23:48 +02007382 /* always unregister in case we don't destroy any domains */
7383 unregister_sched_domain_sysctl();
7384
Paul Jackson029190c2007-10-18 23:40:20 -07007385 if (doms_new == NULL) {
7386 ndoms_new = 1;
7387 doms_new = &fallback_doms;
7388 cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007389 dattr_new = NULL;
Paul Jackson029190c2007-10-18 23:40:20 -07007390 }
7391
7392 /* Destroy deleted domains */
7393 for (i = 0; i < ndoms_cur; i++) {
7394 for (j = 0; j < ndoms_new; j++) {
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007395 if (cpus_equal(doms_cur[i], doms_new[j])
7396 && dattrs_equal(dattr_cur, i, dattr_new, j))
Paul Jackson029190c2007-10-18 23:40:20 -07007397 goto match1;
7398 }
7399 /* no match - a current sched domain not in new doms_new[] */
7400 detach_destroy_domains(doms_cur + i);
7401match1:
7402 ;
7403 }
7404
7405 /* Build new domains */
7406 for (i = 0; i < ndoms_new; i++) {
7407 for (j = 0; j < ndoms_cur; j++) {
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007408 if (cpus_equal(doms_new[i], doms_cur[j])
7409 && dattrs_equal(dattr_new, i, dattr_cur, j))
Paul Jackson029190c2007-10-18 23:40:20 -07007410 goto match2;
7411 }
7412 /* no match - add a new doms_new */
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007413 __build_sched_domains(doms_new + i,
7414 dattr_new ? dattr_new + i : NULL);
Paul Jackson029190c2007-10-18 23:40:20 -07007415match2:
7416 ;
7417 }
7418
7419 /* Remember the new sched domains */
7420 if (doms_cur != &fallback_doms)
7421 kfree(doms_cur);
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007422 kfree(dattr_cur); /* kfree(NULL) is safe */
Paul Jackson029190c2007-10-18 23:40:20 -07007423 doms_cur = doms_new;
Hidetoshi Seto1d3504f2008-04-15 14:04:23 +09007424 dattr_cur = dattr_new;
Paul Jackson029190c2007-10-18 23:40:20 -07007425 ndoms_cur = ndoms_new;
Milton Miller73785472007-10-24 18:23:48 +02007426
7427 register_sched_domain_sysctl();
Srivatsa Vaddagiria1835612008-01-25 21:08:00 +01007428
Heiko Carstens712555e2008-04-28 11:33:07 +02007429 mutex_unlock(&sched_domains_mutex);
Paul Jackson029190c2007-10-18 23:40:20 -07007430}
7431
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007432#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
Heiko Carstens9aefd0a2008-03-12 18:31:58 +01007433int arch_reinit_sched_domains(void)
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007434{
7435 int err;
7436
Gautham R Shenoy95402b32008-01-25 21:08:02 +01007437 get_online_cpus();
Heiko Carstens712555e2008-04-28 11:33:07 +02007438 mutex_lock(&sched_domains_mutex);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007439 detach_destroy_domains(&cpu_online_map);
Max Krasnyansky5c8e1ed2008-05-29 11:17:01 -07007440 free_sched_domains();
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007441 err = arch_init_sched_domains(&cpu_online_map);
Heiko Carstens712555e2008-04-28 11:33:07 +02007442 mutex_unlock(&sched_domains_mutex);
Gautham R Shenoy95402b32008-01-25 21:08:02 +01007443 put_online_cpus();
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007444
7445 return err;
7446}
7447
7448static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
7449{
7450 int ret;
7451
7452 if (buf[0] != '0' && buf[0] != '1')
7453 return -EINVAL;
7454
7455 if (smt)
7456 sched_smt_power_savings = (buf[0] == '1');
7457 else
7458 sched_mc_power_savings = (buf[0] == '1');
7459
7460 ret = arch_reinit_sched_domains();
7461
7462 return ret ? ret : count;
7463}
7464
Adrian Bunk6707de002007-08-12 18:08:19 +02007465#ifdef CONFIG_SCHED_MC
7466static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page)
7467{
7468 return sprintf(page, "%u\n", sched_mc_power_savings);
7469}
7470static ssize_t sched_mc_power_savings_store(struct sys_device *dev,
7471 const char *buf, size_t count)
7472{
7473 return sched_power_savings_store(buf, count, 0);
7474}
7475static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
7476 sched_mc_power_savings_store);
7477#endif
7478
7479#ifdef CONFIG_SCHED_SMT
7480static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page)
7481{
7482 return sprintf(page, "%u\n", sched_smt_power_savings);
7483}
7484static ssize_t sched_smt_power_savings_store(struct sys_device *dev,
7485 const char *buf, size_t count)
7486{
7487 return sched_power_savings_store(buf, count, 1);
7488}
7489static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
7490 sched_smt_power_savings_store);
7491#endif
7492
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007493int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
7494{
7495 int err = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07007496
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007497#ifdef CONFIG_SCHED_SMT
7498 if (smt_capable())
7499 err = sysfs_create_file(&cls->kset.kobj,
7500 &attr_sched_smt_power_savings.attr);
7501#endif
7502#ifdef CONFIG_SCHED_MC
7503 if (!err && mc_capable())
7504 err = sysfs_create_file(&cls->kset.kobj,
7505 &attr_sched_mc_power_savings.attr);
7506#endif
7507 return err;
7508}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02007509#endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07007510
Linus Torvalds1da177e2005-04-16 15:20:36 -07007511/*
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01007512 * Force a reinitialization of the sched domains hierarchy. The domains
Linus Torvalds1da177e2005-04-16 15:20:36 -07007513 * and groups cannot be updated in place without racing with the balancing
Nick Piggin41c7ce92005-06-25 14:57:24 -07007514 * code, so we temporarily attach all running cpus to the NULL domain
Linus Torvalds1da177e2005-04-16 15:20:36 -07007515 * which will prevent rebalancing while the sched domains are recalculated.
7516 */
7517static int update_sched_domains(struct notifier_block *nfb,
7518 unsigned long action, void *hcpu)
7519{
Peter Zijlstra7def2be2008-06-05 14:49:58 +02007520 int cpu = (int)(long)hcpu;
7521
Linus Torvalds1da177e2005-04-16 15:20:36 -07007522 switch (action) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07007523 case CPU_DOWN_PREPARE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07007524 case CPU_DOWN_PREPARE_FROZEN:
Peter Zijlstra7def2be2008-06-05 14:49:58 +02007525 disable_runtime(cpu_rq(cpu));
7526 /* fall-through */
7527 case CPU_UP_PREPARE:
7528 case CPU_UP_PREPARE_FROZEN:
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007529 detach_destroy_domains(&cpu_online_map);
Max Krasnyansky5c8e1ed2008-05-29 11:17:01 -07007530 free_sched_domains();
Linus Torvalds1da177e2005-04-16 15:20:36 -07007531 return NOTIFY_OK;
7532
Peter Zijlstra7def2be2008-06-05 14:49:58 +02007533
Linus Torvalds1da177e2005-04-16 15:20:36 -07007534 case CPU_DOWN_FAILED:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07007535 case CPU_DOWN_FAILED_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07007536 case CPU_ONLINE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07007537 case CPU_ONLINE_FROZEN:
Peter Zijlstra7def2be2008-06-05 14:49:58 +02007538 enable_runtime(cpu_rq(cpu));
7539 /* fall-through */
7540 case CPU_UP_CANCELED:
7541 case CPU_UP_CANCELED_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07007542 case CPU_DEAD:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07007543 case CPU_DEAD_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07007544 /*
7545 * Fall through and re-initialise the domains.
7546 */
7547 break;
7548 default:
7549 return NOTIFY_DONE;
7550 }
7551
Max Krasnyansky5c8e1ed2008-05-29 11:17:01 -07007552#ifndef CONFIG_CPUSETS
7553 /*
7554 * Create default domain partitioning if cpusets are disabled.
7555 * Otherwise we let cpusets rebuild the domains based on the
7556 * current setup.
7557 */
7558
Linus Torvalds1da177e2005-04-16 15:20:36 -07007559 /* The hotplug lock is already held by cpu_up/cpu_down */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007560 arch_init_sched_domains(&cpu_online_map);
Max Krasnyansky5c8e1ed2008-05-29 11:17:01 -07007561#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07007562
7563 return NOTIFY_OK;
7564}
Linus Torvalds1da177e2005-04-16 15:20:36 -07007565
7566void __init sched_init_smp(void)
7567{
Nick Piggin5c1e1762006-10-03 01:14:04 -07007568 cpumask_t non_isolated_cpus;
7569
Mike Travis434d53b2008-04-04 18:11:04 -07007570#if defined(CONFIG_NUMA)
7571 sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **),
7572 GFP_KERNEL);
7573 BUG_ON(sched_group_nodes_bycpu == NULL);
7574#endif
Gautham R Shenoy95402b32008-01-25 21:08:02 +01007575 get_online_cpus();
Heiko Carstens712555e2008-04-28 11:33:07 +02007576 mutex_lock(&sched_domains_mutex);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07007577 arch_init_sched_domains(&cpu_online_map);
Nathan Lynche5e56732007-01-10 23:15:28 -08007578 cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
Nick Piggin5c1e1762006-10-03 01:14:04 -07007579 if (cpus_empty(non_isolated_cpus))
7580 cpu_set(smp_processor_id(), non_isolated_cpus);
Heiko Carstens712555e2008-04-28 11:33:07 +02007581 mutex_unlock(&sched_domains_mutex);
Gautham R Shenoy95402b32008-01-25 21:08:02 +01007582 put_online_cpus();
Linus Torvalds1da177e2005-04-16 15:20:36 -07007583 /* XXX: Theoretical race here - CPU may be hotplugged now */
7584 hotcpu_notifier(update_sched_domains, 0);
Peter Zijlstrab328ca12008-04-29 10:02:46 +02007585 init_hrtick();
Nick Piggin5c1e1762006-10-03 01:14:04 -07007586
7587 /* Move init over to a non-isolated CPU */
Mike Travis7c16ec52008-04-04 18:11:11 -07007588 if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0)
Nick Piggin5c1e1762006-10-03 01:14:04 -07007589 BUG();
Ingo Molnar19978ca2007-11-09 22:39:38 +01007590 sched_init_granularity();
Linus Torvalds1da177e2005-04-16 15:20:36 -07007591}
7592#else
7593void __init sched_init_smp(void)
7594{
Ingo Molnar19978ca2007-11-09 22:39:38 +01007595 sched_init_granularity();
Linus Torvalds1da177e2005-04-16 15:20:36 -07007596}
7597#endif /* CONFIG_SMP */
7598
7599int in_sched_functions(unsigned long addr)
7600{
Linus Torvalds1da177e2005-04-16 15:20:36 -07007601 return in_lock_functions(addr) ||
7602 (addr >= (unsigned long)__sched_text_start
7603 && addr < (unsigned long)__sched_text_end);
7604}
7605
Alexey Dobriyana9957442007-10-15 17:00:13 +02007606static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
Ingo Molnardd41f592007-07-09 18:51:59 +02007607{
7608 cfs_rq->tasks_timeline = RB_ROOT;
Peter Zijlstra4a55bd52008-04-19 19:45:00 +02007609 INIT_LIST_HEAD(&cfs_rq->tasks);
Ingo Molnardd41f592007-07-09 18:51:59 +02007610#ifdef CONFIG_FAIR_GROUP_SCHED
7611 cfs_rq->rq = rq;
7612#endif
Peter Zijlstra67e9fb22007-10-15 17:00:10 +02007613 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
Ingo Molnardd41f592007-07-09 18:51:59 +02007614}
7615
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007616static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq)
7617{
7618 struct rt_prio_array *array;
7619 int i;
7620
7621 array = &rt_rq->active;
7622 for (i = 0; i < MAX_RT_PRIO; i++) {
Gregory Haskins45c01e82008-05-12 21:20:41 +02007623 INIT_LIST_HEAD(array->xqueue + i);
7624 INIT_LIST_HEAD(array->squeue + i);
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007625 __clear_bit(i, array->bitmap);
7626 }
7627 /* delimiter for bitsearch: */
7628 __set_bit(MAX_RT_PRIO, array->bitmap);
7629
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007630#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
Peter Zijlstra48d5e252008-01-25 21:08:31 +01007631 rt_rq->highest_prio = MAX_RT_PRIO;
7632#endif
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007633#ifdef CONFIG_SMP
7634 rt_rq->rt_nr_migratory = 0;
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007635 rt_rq->overloaded = 0;
7636#endif
7637
7638 rt_rq->rt_time = 0;
7639 rt_rq->rt_throttled = 0;
Peter Zijlstraac086bc2008-04-19 19:44:58 +02007640 rt_rq->rt_runtime = 0;
7641 spin_lock_init(&rt_rq->rt_runtime_lock);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007642
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007643#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra23b0fdf2008-02-13 15:45:39 +01007644 rt_rq->rt_nr_boosted = 0;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007645 rt_rq->rq = rq;
7646#endif
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007647}
7648
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007649#ifdef CONFIG_FAIR_GROUP_SCHED
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007650static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq,
7651 struct sched_entity *se, int cpu, int add,
7652 struct sched_entity *parent)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007653{
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007654 struct rq *rq = cpu_rq(cpu);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007655 tg->cfs_rq[cpu] = cfs_rq;
7656 init_cfs_rq(cfs_rq, rq);
7657 cfs_rq->tg = tg;
7658 if (add)
7659 list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
7660
7661 tg->se[cpu] = se;
Dhaval Giani354d60c2008-04-19 19:44:59 +02007662 /* se could be NULL for init_task_group */
7663 if (!se)
7664 return;
7665
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007666 if (!parent)
7667 se->cfs_rq = &rq->cfs;
7668 else
7669 se->cfs_rq = parent->my_q;
7670
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007671 se->my_q = cfs_rq;
7672 se->load.weight = tg->shares;
Peter Zijlstrae05510d2008-05-05 23:56:17 +02007673 se->load.inv_weight = 0;
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007674 se->parent = parent;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007675}
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007676#endif
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007677
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007678#ifdef CONFIG_RT_GROUP_SCHED
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007679static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
7680 struct sched_rt_entity *rt_se, int cpu, int add,
7681 struct sched_rt_entity *parent)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007682{
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007683 struct rq *rq = cpu_rq(cpu);
7684
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007685 tg->rt_rq[cpu] = rt_rq;
7686 init_rt_rq(rt_rq, rq);
7687 rt_rq->tg = tg;
7688 rt_rq->rt_se = rt_se;
Peter Zijlstraac086bc2008-04-19 19:44:58 +02007689 rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007690 if (add)
7691 list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list);
7692
7693 tg->rt_se[cpu] = rt_se;
Dhaval Giani354d60c2008-04-19 19:44:59 +02007694 if (!rt_se)
7695 return;
7696
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007697 if (!parent)
7698 rt_se->rt_rq = &rq->rt;
7699 else
7700 rt_se->rt_rq = parent->my_q;
7701
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007702 rt_se->rt_rq = &rq->rt;
7703 rt_se->my_q = rt_rq;
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007704 rt_se->parent = parent;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007705 INIT_LIST_HEAD(&rt_se->run_list);
7706}
7707#endif
7708
Linus Torvalds1da177e2005-04-16 15:20:36 -07007709void __init sched_init(void)
7710{
Ingo Molnardd41f592007-07-09 18:51:59 +02007711 int i, j;
Mike Travis434d53b2008-04-04 18:11:04 -07007712 unsigned long alloc_size = 0, ptr;
7713
7714#ifdef CONFIG_FAIR_GROUP_SCHED
7715 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7716#endif
7717#ifdef CONFIG_RT_GROUP_SCHED
7718 alloc_size += 2 * nr_cpu_ids * sizeof(void **);
7719#endif
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007720#ifdef CONFIG_USER_SCHED
7721 alloc_size *= 2;
7722#endif
Mike Travis434d53b2008-04-04 18:11:04 -07007723 /*
7724 * As sched_init() is called before page_alloc is setup,
7725 * we use alloc_bootmem().
7726 */
7727 if (alloc_size) {
David Miller5a9d3222008-04-24 20:46:20 -07007728 ptr = (unsigned long)alloc_bootmem(alloc_size);
Mike Travis434d53b2008-04-04 18:11:04 -07007729
7730#ifdef CONFIG_FAIR_GROUP_SCHED
7731 init_task_group.se = (struct sched_entity **)ptr;
7732 ptr += nr_cpu_ids * sizeof(void **);
7733
7734 init_task_group.cfs_rq = (struct cfs_rq **)ptr;
7735 ptr += nr_cpu_ids * sizeof(void **);
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007736
7737#ifdef CONFIG_USER_SCHED
7738 root_task_group.se = (struct sched_entity **)ptr;
7739 ptr += nr_cpu_ids * sizeof(void **);
7740
7741 root_task_group.cfs_rq = (struct cfs_rq **)ptr;
7742 ptr += nr_cpu_ids * sizeof(void **);
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02007743#endif /* CONFIG_USER_SCHED */
7744#endif /* CONFIG_FAIR_GROUP_SCHED */
Mike Travis434d53b2008-04-04 18:11:04 -07007745#ifdef CONFIG_RT_GROUP_SCHED
7746 init_task_group.rt_se = (struct sched_rt_entity **)ptr;
7747 ptr += nr_cpu_ids * sizeof(void **);
7748
7749 init_task_group.rt_rq = (struct rt_rq **)ptr;
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007750 ptr += nr_cpu_ids * sizeof(void **);
7751
7752#ifdef CONFIG_USER_SCHED
7753 root_task_group.rt_se = (struct sched_rt_entity **)ptr;
7754 ptr += nr_cpu_ids * sizeof(void **);
7755
7756 root_task_group.rt_rq = (struct rt_rq **)ptr;
7757 ptr += nr_cpu_ids * sizeof(void **);
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02007758#endif /* CONFIG_USER_SCHED */
7759#endif /* CONFIG_RT_GROUP_SCHED */
Mike Travis434d53b2008-04-04 18:11:04 -07007760 }
Ingo Molnardd41f592007-07-09 18:51:59 +02007761
Gregory Haskins57d885f2008-01-25 21:08:18 +01007762#ifdef CONFIG_SMP
7763 init_defrootdomain();
7764#endif
7765
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02007766 init_rt_bandwidth(&def_rt_bandwidth,
7767 global_rt_period(), global_rt_runtime());
7768
7769#ifdef CONFIG_RT_GROUP_SCHED
7770 init_rt_bandwidth(&init_task_group.rt_bandwidth,
7771 global_rt_period(), global_rt_runtime());
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007772#ifdef CONFIG_USER_SCHED
7773 init_rt_bandwidth(&root_task_group.rt_bandwidth,
7774 global_rt_period(), RUNTIME_INF);
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02007775#endif /* CONFIG_USER_SCHED */
7776#endif /* CONFIG_RT_GROUP_SCHED */
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02007777
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007778#ifdef CONFIG_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007779 list_add(&init_task_group.list, &task_groups);
Peter Zijlstraf473aa52008-04-19 19:45:00 +02007780 INIT_LIST_HEAD(&init_task_group.children);
7781
7782#ifdef CONFIG_USER_SCHED
7783 INIT_LIST_HEAD(&root_task_group.children);
7784 init_task_group.parent = &root_task_group;
7785 list_add(&init_task_group.siblings, &root_task_group.children);
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02007786#endif /* CONFIG_USER_SCHED */
7787#endif /* CONFIG_GROUP_SCHED */
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007788
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08007789 for_each_possible_cpu(i) {
Ingo Molnar70b97a72006-07-03 00:25:42 -07007790 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007791
7792 rq = cpu_rq(i);
7793 spin_lock_init(&rq->lock);
Ingo Molnarfcb99372006-07-03 00:25:10 -07007794 lockdep_set_class(&rq->lock, &rq->rq_lock_key);
Nick Piggin78979862005-06-25 14:57:13 -07007795 rq->nr_running = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02007796 init_cfs_rq(&rq->cfs, rq);
Peter Zijlstrafa85ae22008-01-25 21:08:29 +01007797 init_rt_rq(&rq->rt, rq);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007798#ifdef CONFIG_FAIR_GROUP_SCHED
7799 init_task_group.shares = init_task_group_load;
7800 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007801#ifdef CONFIG_CGROUP_SCHED
7802 /*
7803 * How much cpu bandwidth does init_task_group get?
7804 *
7805 * In case of task-groups formed thr' the cgroup filesystem, it
7806 * gets 100% of the cpu resources in the system. This overall
7807 * system cpu resource is divided among the tasks of
7808 * init_task_group and its child task-groups in a fair manner,
7809 * based on each entity's (task or task-group's) weight
7810 * (se->load.weight).
7811 *
7812 * In other words, if init_task_group has 10 tasks of weight
7813 * 1024) and two child groups A0 and A1 (of weight 1024 each),
7814 * then A0's share of the cpu resource is:
7815 *
7816 * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33%
7817 *
7818 * We achieve this by letting init_task_group's tasks sit
7819 * directly in rq->cfs (i.e init_task_group->se[] = NULL).
7820 */
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007821 init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007822#elif defined CONFIG_USER_SCHED
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007823 root_task_group.shares = NICE_0_LOAD;
7824 init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007825 /*
7826 * In case of task-groups formed thr' the user id of tasks,
7827 * init_task_group represents tasks belonging to root user.
7828 * Hence it forms a sibling of all subsequent groups formed.
7829 * In this case, init_task_group gets only a fraction of overall
7830 * system cpu resource, based on the weight assigned to root
7831 * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished
7832 * by letting tasks of init_task_group sit in a separate cfs_rq
7833 * (init_cfs_rq) and having one entity represent this group of
7834 * tasks in rq->cfs (i.e init_task_group->se[] != NULL).
7835 */
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007836 init_tg_cfs_entry(&init_task_group,
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007837 &per_cpu(init_cfs_rq, i),
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007838 &per_cpu(init_sched_entity, i), i, 1,
7839 root_task_group.se[i]);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007840
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007841#endif
Dhaval Giani354d60c2008-04-19 19:44:59 +02007842#endif /* CONFIG_FAIR_GROUP_SCHED */
7843
7844 rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01007845#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007846 INIT_LIST_HEAD(&rq->leaf_rt_rq_list);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007847#ifdef CONFIG_CGROUP_SCHED
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007848 init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007849#elif defined CONFIG_USER_SCHED
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007850 init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL);
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02007851 init_tg_rt_entry(&init_task_group,
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007852 &per_cpu(init_rt_rq, i),
Peter Zijlstraeff766a2008-04-19 19:45:00 +02007853 &per_cpu(init_sched_rt_entity, i), i, 1,
7854 root_task_group.rt_se[i]);
Dhaval Giani354d60c2008-04-19 19:44:59 +02007855#endif
Peter Zijlstra6f505b12008-01-25 21:08:30 +01007856#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07007857
Ingo Molnardd41f592007-07-09 18:51:59 +02007858 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
7859 rq->cpu_load[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007860#ifdef CONFIG_SMP
Nick Piggin41c7ce92005-06-25 14:57:24 -07007861 rq->sd = NULL;
Gregory Haskins57d885f2008-01-25 21:08:18 +01007862 rq->rd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007863 rq->active_balance = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02007864 rq->next_balance = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007865 rq->push_cpu = 0;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07007866 rq->cpu = i;
Gregory Haskins1f11eb62008-06-04 15:04:05 -04007867 rq->online = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007868 rq->migration_thread = NULL;
7869 INIT_LIST_HEAD(&rq->migration_queue);
Gregory Haskinsdc938522008-01-25 21:08:26 +01007870 rq_attach_root(rq, &def_root_domain);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007871#endif
Peter Zijlstra8f4d37e2008-01-25 21:08:29 +01007872 init_rq_hrtick(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007873 atomic_set(&rq->nr_iowait, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007874 }
7875
Peter Williams2dd73a42006-06-27 02:54:34 -07007876 set_load_weight(&init_task);
Heiko Carstensb50f60c2006-07-30 03:03:52 -07007877
Avi Kivitye107be32007-07-26 13:40:43 +02007878#ifdef CONFIG_PREEMPT_NOTIFIERS
7879 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
7880#endif
7881
Christoph Lameterc9819f42006-12-10 02:20:25 -08007882#ifdef CONFIG_SMP
7883 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
7884#endif
7885
Heiko Carstensb50f60c2006-07-30 03:03:52 -07007886#ifdef CONFIG_RT_MUTEXES
7887 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
7888#endif
7889
Linus Torvalds1da177e2005-04-16 15:20:36 -07007890 /*
7891 * The boot idle thread does lazy MMU switching as well:
7892 */
7893 atomic_inc(&init_mm.mm_count);
7894 enter_lazy_tlb(&init_mm, current);
7895
7896 /*
7897 * Make us the idle thread. Technically, schedule() should not be
7898 * called from this thread, however somewhere below it might be,
7899 * but because we are the idle thread, we just pick up running again
7900 * when this runqueue becomes "idle".
7901 */
7902 init_idle(current, smp_processor_id());
Ingo Molnardd41f592007-07-09 18:51:59 +02007903 /*
7904 * During early bootup we pretend to be a normal task:
7905 */
7906 current->sched_class = &fair_sched_class;
Ingo Molnar6892b752008-02-13 14:02:36 +01007907
7908 scheduler_running = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007909}
7910
7911#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
7912void __might_sleep(char *file, int line)
7913{
Ingo Molnar48f24c42006-07-03 00:25:40 -07007914#ifdef in_atomic
Linus Torvalds1da177e2005-04-16 15:20:36 -07007915 static unsigned long prev_jiffy; /* ratelimiting */
7916
7917 if ((in_atomic() || irqs_disabled()) &&
7918 system_state == SYSTEM_RUNNING && !oops_in_progress) {
7919 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
7920 return;
7921 prev_jiffy = jiffies;
Ingo Molnar91368d72006-03-23 03:00:54 -08007922 printk(KERN_ERR "BUG: sleeping function called from invalid"
Linus Torvalds1da177e2005-04-16 15:20:36 -07007923 " context at %s:%d\n", file, line);
7924 printk("in_atomic():%d, irqs_disabled():%d\n",
7925 in_atomic(), irqs_disabled());
Peter Zijlstraa4c410f2006-12-06 20:37:21 -08007926 debug_show_held_locks(current);
Ingo Molnar3117df02006-12-13 00:34:43 -08007927 if (irqs_disabled())
7928 print_irqtrace_events(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007929 dump_stack();
7930 }
7931#endif
7932}
7933EXPORT_SYMBOL(__might_sleep);
7934#endif
7935
7936#ifdef CONFIG_MAGIC_SYSRQ
Andi Kleen3a5e4dc2007-10-15 17:00:15 +02007937static void normalize_task(struct rq *rq, struct task_struct *p)
7938{
7939 int on_rq;
Peter Zijlstra3e51f332008-05-03 18:29:28 +02007940
Andi Kleen3a5e4dc2007-10-15 17:00:15 +02007941 update_rq_clock(rq);
7942 on_rq = p->se.on_rq;
7943 if (on_rq)
7944 deactivate_task(rq, p, 0);
7945 __setscheduler(rq, p, SCHED_NORMAL, 0);
7946 if (on_rq) {
7947 activate_task(rq, p, 0);
7948 resched_task(rq->curr);
7949 }
7950}
7951
Linus Torvalds1da177e2005-04-16 15:20:36 -07007952void normalize_rt_tasks(void)
7953{
Ingo Molnara0f98a12007-06-17 18:37:45 +02007954 struct task_struct *g, *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007955 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07007956 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07007957
Peter Zijlstra4cf5d772008-02-13 15:45:39 +01007958 read_lock_irqsave(&tasklist_lock, flags);
Ingo Molnara0f98a12007-06-17 18:37:45 +02007959 do_each_thread(g, p) {
Ingo Molnar178be792007-10-15 17:00:18 +02007960 /*
7961 * Only normalize user tasks:
7962 */
7963 if (!p->mm)
7964 continue;
7965
Ingo Molnardd41f592007-07-09 18:51:59 +02007966 p->se.exec_start = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02007967#ifdef CONFIG_SCHEDSTATS
7968 p->se.wait_start = 0;
7969 p->se.sleep_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02007970 p->se.block_start = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02007971#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02007972
7973 if (!rt_task(p)) {
7974 /*
7975 * Renice negative nice level userspace
7976 * tasks back to 0:
7977 */
7978 if (TASK_NICE(p) < 0 && p->mm)
7979 set_user_nice(p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007980 continue;
Ingo Molnardd41f592007-07-09 18:51:59 +02007981 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07007982
Peter Zijlstra4cf5d772008-02-13 15:45:39 +01007983 spin_lock(&p->pi_lock);
Ingo Molnarb29739f2006-06-27 02:54:51 -07007984 rq = __task_rq_lock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007985
Ingo Molnar178be792007-10-15 17:00:18 +02007986 normalize_task(rq, p);
Andi Kleen3a5e4dc2007-10-15 17:00:15 +02007987
Ingo Molnarb29739f2006-06-27 02:54:51 -07007988 __task_rq_unlock(rq);
Peter Zijlstra4cf5d772008-02-13 15:45:39 +01007989 spin_unlock(&p->pi_lock);
Ingo Molnara0f98a12007-06-17 18:37:45 +02007990 } while_each_thread(g, p);
7991
Peter Zijlstra4cf5d772008-02-13 15:45:39 +01007992 read_unlock_irqrestore(&tasklist_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07007993}
7994
7995#endif /* CONFIG_MAGIC_SYSRQ */
Linus Torvalds1df5c102005-09-12 07:59:21 -07007996
7997#ifdef CONFIG_IA64
7998/*
7999 * These functions are only useful for the IA64 MCA handling.
8000 *
8001 * They can only be called when the whole system has been
8002 * stopped - every CPU needs to be quiescent, and no scheduling
8003 * activity can take place. Using them for anything else would
8004 * be a serious bug, and as a result, they aren't even visible
8005 * under any other configuration.
8006 */
8007
8008/**
8009 * curr_task - return the current task for a given cpu.
8010 * @cpu: the processor in question.
8011 *
8012 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8013 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07008014struct task_struct *curr_task(int cpu)
Linus Torvalds1df5c102005-09-12 07:59:21 -07008015{
8016 return cpu_curr(cpu);
8017}
8018
8019/**
8020 * set_curr_task - set the current task for a given cpu.
8021 * @cpu: the processor in question.
8022 * @p: the task pointer to set.
8023 *
8024 * Description: This function must only be used when non-maskable interrupts
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01008025 * are serviced on a separate stack. It allows the architecture to switch the
8026 * notion of the current task on a cpu in a non-blocking manner. This function
Linus Torvalds1df5c102005-09-12 07:59:21 -07008027 * must be called with all CPU's synchronized, and interrupts disabled, the
8028 * and caller must save the original value of the current task (see
8029 * curr_task() above) and restore that value before reenabling interrupts and
8030 * re-starting the system.
8031 *
8032 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
8033 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07008034void set_curr_task(int cpu, struct task_struct *p)
Linus Torvalds1df5c102005-09-12 07:59:21 -07008035{
8036 cpu_curr(cpu) = p;
8037}
8038
8039#endif
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008040
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008041#ifdef CONFIG_FAIR_GROUP_SCHED
8042static void free_fair_sched_group(struct task_group *tg)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008043{
8044 int i;
8045
8046 for_each_possible_cpu(i) {
8047 if (tg->cfs_rq)
8048 kfree(tg->cfs_rq[i]);
8049 if (tg->se)
8050 kfree(tg->se[i]);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008051 }
8052
8053 kfree(tg->cfs_rq);
8054 kfree(tg->se);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008055}
8056
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008057static
8058int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008059{
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008060 struct cfs_rq *cfs_rq;
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008061 struct sched_entity *se, *parent_se;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008062 struct rq *rq;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008063 int i;
8064
Mike Travis434d53b2008-04-04 18:11:04 -07008065 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008066 if (!tg->cfs_rq)
8067 goto err;
Mike Travis434d53b2008-04-04 18:11:04 -07008068 tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008069 if (!tg->se)
8070 goto err;
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008071
8072 tg->shares = NICE_0_LOAD;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008073
8074 for_each_possible_cpu(i) {
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008075 rq = cpu_rq(i);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008076
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008077 cfs_rq = kmalloc_node(sizeof(struct cfs_rq),
8078 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008079 if (!cfs_rq)
8080 goto err;
8081
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008082 se = kmalloc_node(sizeof(struct sched_entity),
8083 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008084 if (!se)
8085 goto err;
8086
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008087 parent_se = parent ? parent->se[i] : NULL;
8088 init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008089 }
8090
8091 return 1;
8092
8093 err:
8094 return 0;
8095}
8096
8097static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8098{
8099 list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list,
8100 &cpu_rq(cpu)->leaf_cfs_rq_list);
8101}
8102
8103static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8104{
8105 list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list);
8106}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008107#else /* !CONFG_FAIR_GROUP_SCHED */
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008108static inline void free_fair_sched_group(struct task_group *tg)
8109{
8110}
8111
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008112static inline
8113int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent)
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008114{
8115 return 1;
8116}
8117
8118static inline void register_fair_sched_group(struct task_group *tg, int cpu)
8119{
8120}
8121
8122static inline void unregister_fair_sched_group(struct task_group *tg, int cpu)
8123{
8124}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008125#endif /* CONFIG_FAIR_GROUP_SCHED */
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008126
8127#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008128static void free_rt_sched_group(struct task_group *tg)
8129{
8130 int i;
8131
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008132 destroy_rt_bandwidth(&tg->rt_bandwidth);
8133
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008134 for_each_possible_cpu(i) {
8135 if (tg->rt_rq)
8136 kfree(tg->rt_rq[i]);
8137 if (tg->rt_se)
8138 kfree(tg->rt_se[i]);
8139 }
8140
8141 kfree(tg->rt_rq);
8142 kfree(tg->rt_se);
8143}
8144
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008145static
8146int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008147{
8148 struct rt_rq *rt_rq;
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008149 struct sched_rt_entity *rt_se, *parent_se;
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008150 struct rq *rq;
8151 int i;
8152
Mike Travis434d53b2008-04-04 18:11:04 -07008153 tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008154 if (!tg->rt_rq)
8155 goto err;
Mike Travis434d53b2008-04-04 18:11:04 -07008156 tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008157 if (!tg->rt_se)
8158 goto err;
8159
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008160 init_rt_bandwidth(&tg->rt_bandwidth,
8161 ktime_to_ns(def_rt_bandwidth.rt_period), 0);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008162
8163 for_each_possible_cpu(i) {
8164 rq = cpu_rq(i);
8165
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008166 rt_rq = kmalloc_node(sizeof(struct rt_rq),
8167 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8168 if (!rt_rq)
8169 goto err;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008170
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008171 rt_se = kmalloc_node(sizeof(struct sched_rt_entity),
8172 GFP_KERNEL|__GFP_ZERO, cpu_to_node(i));
8173 if (!rt_se)
8174 goto err;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008175
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008176 parent_se = parent ? parent->rt_se[i] : NULL;
8177 init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008178 }
8179
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008180 return 1;
8181
8182 err:
8183 return 0;
8184}
8185
8186static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8187{
8188 list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list,
8189 &cpu_rq(cpu)->leaf_rt_rq_list);
8190}
8191
8192static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8193{
8194 list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list);
8195}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008196#else /* !CONFIG_RT_GROUP_SCHED */
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008197static inline void free_rt_sched_group(struct task_group *tg)
8198{
8199}
8200
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008201static inline
8202int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008203{
8204 return 1;
8205}
8206
8207static inline void register_rt_sched_group(struct task_group *tg, int cpu)
8208{
8209}
8210
8211static inline void unregister_rt_sched_group(struct task_group *tg, int cpu)
8212{
8213}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008214#endif /* CONFIG_RT_GROUP_SCHED */
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008215
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008216#ifdef CONFIG_GROUP_SCHED
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008217static void free_sched_group(struct task_group *tg)
8218{
8219 free_fair_sched_group(tg);
8220 free_rt_sched_group(tg);
8221 kfree(tg);
8222}
8223
8224/* allocate runqueue etc for a new task group */
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008225struct task_group *sched_create_group(struct task_group *parent)
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008226{
8227 struct task_group *tg;
8228 unsigned long flags;
8229 int i;
8230
8231 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
8232 if (!tg)
8233 return ERR_PTR(-ENOMEM);
8234
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008235 if (!alloc_fair_sched_group(tg, parent))
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008236 goto err;
8237
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008238 if (!alloc_rt_sched_group(tg, parent))
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008239 goto err;
8240
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008241 spin_lock_irqsave(&task_group_lock, flags);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008242 for_each_possible_cpu(i) {
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008243 register_fair_sched_group(tg, i);
8244 register_rt_sched_group(tg, i);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008245 }
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008246 list_add_rcu(&tg->list, &task_groups);
Peter Zijlstraf473aa52008-04-19 19:45:00 +02008247
8248 WARN_ON(!parent); /* root should already exist */
8249
8250 tg->parent = parent;
8251 list_add_rcu(&tg->siblings, &parent->children);
8252 INIT_LIST_HEAD(&tg->children);
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008253 spin_unlock_irqrestore(&task_group_lock, flags);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008254
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008255 return tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008256
8257err:
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008258 free_sched_group(tg);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008259 return ERR_PTR(-ENOMEM);
8260}
8261
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008262/* rcu callback to free various structures associated with a task group */
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008263static void free_sched_group_rcu(struct rcu_head *rhp)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008264{
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008265 /* now it should be safe to free those cfs_rqs */
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008266 free_sched_group(container_of(rhp, struct task_group, rcu));
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008267}
8268
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008269/* Destroy runqueue etc associated with a task group */
Ingo Molnar4cf86d72007-10-15 17:00:14 +02008270void sched_destroy_group(struct task_group *tg)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008271{
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008272 unsigned long flags;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008273 int i;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008274
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008275 spin_lock_irqsave(&task_group_lock, flags);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008276 for_each_possible_cpu(i) {
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008277 unregister_fair_sched_group(tg, i);
8278 unregister_rt_sched_group(tg, i);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008279 }
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008280 list_del_rcu(&tg->list);
Peter Zijlstraf473aa52008-04-19 19:45:00 +02008281 list_del_rcu(&tg->siblings);
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008282 spin_unlock_irqrestore(&task_group_lock, flags);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008283
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008284 /* wait for possible concurrent references to cfs_rqs complete */
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008285 call_rcu(&tg->rcu, free_sched_group_rcu);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008286}
8287
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008288/* change task's runqueue when it moves between groups.
Ingo Molnar3a252012007-10-15 17:00:12 +02008289 * The caller of this function should have put the task in its new group
8290 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
8291 * reflect its new group.
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008292 */
8293void sched_move_task(struct task_struct *tsk)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008294{
8295 int on_rq, running;
8296 unsigned long flags;
8297 struct rq *rq;
8298
8299 rq = task_rq_lock(tsk, &flags);
8300
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008301 update_rq_clock(rq);
8302
Dmitry Adamushko051a1d12007-12-18 15:21:13 +01008303 running = task_current(rq, tsk);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008304 on_rq = tsk->se.on_rq;
8305
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07008306 if (on_rq)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008307 dequeue_task(rq, tsk, 0);
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07008308 if (unlikely(running))
8309 tsk->sched_class->put_prev_task(rq, tsk);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008310
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008311 set_task_rq(tsk, task_cpu(tsk));
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008312
Peter Zijlstra810b3812008-02-29 15:21:01 -05008313#ifdef CONFIG_FAIR_GROUP_SCHED
8314 if (tsk->sched_class->moved_group)
8315 tsk->sched_class->moved_group(tsk);
8316#endif
8317
Hiroshi Shimamoto0e1f3482008-03-10 11:01:20 -07008318 if (unlikely(running))
8319 tsk->sched_class->set_curr_task(rq);
8320 if (on_rq)
Dmitry Adamushko7074bad2007-10-15 17:00:07 +02008321 enqueue_task(rq, tsk, 0);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008322
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008323 task_rq_unlock(rq, &flags);
8324}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008325#endif /* CONFIG_GROUP_SCHED */
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008326
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008327#ifdef CONFIG_FAIR_GROUP_SCHED
Ingo Molnar6363ca52008-05-29 11:28:57 +02008328static void set_se_shares(struct sched_entity *se, unsigned long shares)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008329{
8330 struct cfs_rq *cfs_rq = se->cfs_rq;
Ingo Molnar6363ca52008-05-29 11:28:57 +02008331 struct rq *rq = cfs_rq->rq;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008332 int on_rq;
8333
Ingo Molnar6363ca52008-05-29 11:28:57 +02008334 spin_lock_irq(&rq->lock);
8335
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008336 on_rq = se->on_rq;
Peter Zijlstra62fb1852008-02-25 17:34:02 +01008337 if (on_rq)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008338 dequeue_entity(cfs_rq, se, 0);
8339
8340 se->load.weight = shares;
Peter Zijlstrae05510d2008-05-05 23:56:17 +02008341 se->load.inv_weight = 0;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008342
Peter Zijlstra62fb1852008-02-25 17:34:02 +01008343 if (on_rq)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008344 enqueue_entity(cfs_rq, se, 0);
Peter Zijlstra62fb1852008-02-25 17:34:02 +01008345
Ingo Molnar6363ca52008-05-29 11:28:57 +02008346 spin_unlock_irq(&rq->lock);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008347}
8348
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008349static DEFINE_MUTEX(shares_mutex);
8350
Ingo Molnar4cf86d72007-10-15 17:00:14 +02008351int sched_group_set_shares(struct task_group *tg, unsigned long shares)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008352{
8353 int i;
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008354 unsigned long flags;
Ingo Molnarc61935f2008-01-22 11:24:58 +01008355
Peter Zijlstra62fb1852008-02-25 17:34:02 +01008356 /*
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008357 * We can't change the weight of the root cgroup.
8358 */
8359 if (!tg->se[0])
8360 return -EINVAL;
8361
Peter Zijlstra18d95a22008-04-19 19:45:00 +02008362 if (shares < MIN_SHARES)
8363 shares = MIN_SHARES;
Miao Xiecb4ad1f2008-04-28 12:54:56 +08008364 else if (shares > MAX_SHARES)
8365 shares = MAX_SHARES;
Peter Zijlstra62fb1852008-02-25 17:34:02 +01008366
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008367 mutex_lock(&shares_mutex);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008368 if (tg->shares == shares)
Dhaval Giani5cb350b2007-10-15 17:00:14 +02008369 goto done;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008370
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008371 spin_lock_irqsave(&task_group_lock, flags);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008372 for_each_possible_cpu(i)
8373 unregister_fair_sched_group(tg, i);
Peter Zijlstraf473aa52008-04-19 19:45:00 +02008374 list_del_rcu(&tg->siblings);
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008375 spin_unlock_irqrestore(&task_group_lock, flags);
Srivatsa Vaddagiri6b2d7702008-01-25 21:08:00 +01008376
8377 /* wait for any ongoing reference to this group to finish */
8378 synchronize_sched();
8379
8380 /*
8381 * Now we are free to modify the group's share on each cpu
8382 * w/o tripping rebalance_share or load_balance_fair.
8383 */
8384 tg->shares = shares;
Ingo Molnar6363ca52008-05-29 11:28:57 +02008385 for_each_possible_cpu(i)
Miao Xiecb4ad1f2008-04-28 12:54:56 +08008386 set_se_shares(tg->se[i], shares);
Srivatsa Vaddagiri6b2d7702008-01-25 21:08:00 +01008387
8388 /*
8389 * Enable load balance activity on this group, by inserting it back on
8390 * each cpu's rq->leaf_cfs_rq_list.
8391 */
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008392 spin_lock_irqsave(&task_group_lock, flags);
Peter Zijlstrabccbe082008-02-13 15:45:40 +01008393 for_each_possible_cpu(i)
8394 register_fair_sched_group(tg, i);
Peter Zijlstraf473aa52008-04-19 19:45:00 +02008395 list_add_rcu(&tg->siblings, &tg->parent->children);
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008396 spin_unlock_irqrestore(&task_group_lock, flags);
Dhaval Giani5cb350b2007-10-15 17:00:14 +02008397done:
Peter Zijlstra8ed36992008-02-13 15:45:39 +01008398 mutex_unlock(&shares_mutex);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02008399 return 0;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02008400}
8401
Dhaval Giani5cb350b2007-10-15 17:00:14 +02008402unsigned long sched_group_shares(struct task_group *tg)
8403{
8404 return tg->shares;
8405}
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008406#endif
Dhaval Giani5cb350b2007-10-15 17:00:14 +02008407
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008408#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008409/*
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008410 * Ensure that the real time constraints are schedulable.
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008411 */
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008412static DEFINE_MUTEX(rt_constraints_mutex);
8413
8414static unsigned long to_ratio(u64 period, u64 runtime)
8415{
8416 if (runtime == RUNTIME_INF)
8417 return 1ULL << 16;
8418
Roman Zippel6f6d6a12008-05-01 04:34:28 -07008419 return div64_u64(runtime << 16, period);
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008420}
8421
Peter Zijlstrab40b2e82008-04-19 19:45:00 +02008422#ifdef CONFIG_CGROUP_SCHED
8423static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
8424{
8425 struct task_group *tgi, *parent = tg->parent;
8426 unsigned long total = 0;
8427
8428 if (!parent) {
8429 if (global_rt_period() < period)
8430 return 0;
8431
8432 return to_ratio(period, runtime) <
8433 to_ratio(global_rt_period(), global_rt_runtime());
8434 }
8435
8436 if (ktime_to_ns(parent->rt_bandwidth.rt_period) < period)
8437 return 0;
8438
8439 rcu_read_lock();
8440 list_for_each_entry_rcu(tgi, &parent->children, siblings) {
8441 if (tgi == tg)
8442 continue;
8443
8444 total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
8445 tgi->rt_bandwidth.rt_runtime);
8446 }
8447 rcu_read_unlock();
8448
8449 return total + to_ratio(period, runtime) <
8450 to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period),
8451 parent->rt_bandwidth.rt_runtime);
8452}
8453#elif defined CONFIG_USER_SCHED
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008454static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008455{
8456 struct task_group *tgi;
8457 unsigned long total = 0;
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008458 unsigned long global_ratio =
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008459 to_ratio(global_rt_period(), global_rt_runtime());
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008460
8461 rcu_read_lock();
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008462 list_for_each_entry_rcu(tgi, &task_groups, list) {
8463 if (tgi == tg)
8464 continue;
8465
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008466 total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period),
8467 tgi->rt_bandwidth.rt_runtime);
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008468 }
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008469 rcu_read_unlock();
8470
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008471 return total + to_ratio(period, runtime) < global_ratio;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008472}
Peter Zijlstrab40b2e82008-04-19 19:45:00 +02008473#endif
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008474
Dhaval Giani521f1a242008-02-28 15:21:56 +05308475/* Must be called with tasklist_lock held */
8476static inline int tg_has_rt_tasks(struct task_group *tg)
8477{
8478 struct task_struct *g, *p;
8479 do_each_thread(g, p) {
8480 if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg)
8481 return 1;
8482 } while_each_thread(g, p);
8483 return 0;
8484}
8485
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008486static int tg_set_bandwidth(struct task_group *tg,
8487 u64 rt_period, u64 rt_runtime)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008488{
Peter Zijlstraac086bc2008-04-19 19:44:58 +02008489 int i, err = 0;
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008490
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008491 mutex_lock(&rt_constraints_mutex);
Dhaval Giani521f1a242008-02-28 15:21:56 +05308492 read_lock(&tasklist_lock);
Peter Zijlstraac086bc2008-04-19 19:44:58 +02008493 if (rt_runtime == 0 && tg_has_rt_tasks(tg)) {
Dhaval Giani521f1a242008-02-28 15:21:56 +05308494 err = -EBUSY;
8495 goto unlock;
8496 }
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008497 if (!__rt_schedulable(tg, rt_period, rt_runtime)) {
8498 err = -EINVAL;
8499 goto unlock;
8500 }
Peter Zijlstraac086bc2008-04-19 19:44:58 +02008501
8502 spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008503 tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
8504 tg->rt_bandwidth.rt_runtime = rt_runtime;
Peter Zijlstraac086bc2008-04-19 19:44:58 +02008505
8506 for_each_possible_cpu(i) {
8507 struct rt_rq *rt_rq = tg->rt_rq[i];
8508
8509 spin_lock(&rt_rq->rt_runtime_lock);
8510 rt_rq->rt_runtime = rt_runtime;
8511 spin_unlock(&rt_rq->rt_runtime_lock);
8512 }
8513 spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008514 unlock:
Dhaval Giani521f1a242008-02-28 15:21:56 +05308515 read_unlock(&tasklist_lock);
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008516 mutex_unlock(&rt_constraints_mutex);
8517
8518 return err;
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008519}
8520
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008521int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
8522{
8523 u64 rt_runtime, rt_period;
8524
8525 rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
8526 rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
8527 if (rt_runtime_us < 0)
8528 rt_runtime = RUNTIME_INF;
8529
8530 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8531}
8532
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008533long sched_group_rt_runtime(struct task_group *tg)
8534{
8535 u64 rt_runtime_us;
8536
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008537 if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008538 return -1;
8539
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008540 rt_runtime_us = tg->rt_bandwidth.rt_runtime;
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008541 do_div(rt_runtime_us, NSEC_PER_USEC);
8542 return rt_runtime_us;
8543}
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008544
8545int sched_group_set_rt_period(struct task_group *tg, long rt_period_us)
8546{
8547 u64 rt_runtime, rt_period;
8548
8549 rt_period = (u64)rt_period_us * NSEC_PER_USEC;
8550 rt_runtime = tg->rt_bandwidth.rt_runtime;
8551
8552 return tg_set_bandwidth(tg, rt_period, rt_runtime);
8553}
8554
8555long sched_group_rt_period(struct task_group *tg)
8556{
8557 u64 rt_period_us;
8558
8559 rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
8560 do_div(rt_period_us, NSEC_PER_USEC);
8561 return rt_period_us;
8562}
8563
8564static int sched_rt_global_constraints(void)
8565{
8566 int ret = 0;
8567
8568 mutex_lock(&rt_constraints_mutex);
8569 if (!__rt_schedulable(NULL, 1, 0))
8570 ret = -EINVAL;
8571 mutex_unlock(&rt_constraints_mutex);
8572
8573 return ret;
8574}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008575#else /* !CONFIG_RT_GROUP_SCHED */
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008576static int sched_rt_global_constraints(void)
8577{
Peter Zijlstraac086bc2008-04-19 19:44:58 +02008578 unsigned long flags;
8579 int i;
8580
8581 spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
8582 for_each_possible_cpu(i) {
8583 struct rt_rq *rt_rq = &cpu_rq(i)->rt;
8584
8585 spin_lock(&rt_rq->rt_runtime_lock);
8586 rt_rq->rt_runtime = global_rt_runtime();
8587 spin_unlock(&rt_rq->rt_runtime_lock);
8588 }
8589 spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
8590
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008591 return 0;
8592}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008593#endif /* CONFIG_RT_GROUP_SCHED */
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008594
8595int sched_rt_handler(struct ctl_table *table, int write,
8596 struct file *filp, void __user *buffer, size_t *lenp,
8597 loff_t *ppos)
8598{
8599 int ret;
8600 int old_period, old_runtime;
8601 static DEFINE_MUTEX(mutex);
8602
8603 mutex_lock(&mutex);
8604 old_period = sysctl_sched_rt_period;
8605 old_runtime = sysctl_sched_rt_runtime;
8606
8607 ret = proc_dointvec(table, write, filp, buffer, lenp, ppos);
8608
8609 if (!ret && write) {
8610 ret = sched_rt_global_constraints();
8611 if (ret) {
8612 sysctl_sched_rt_period = old_period;
8613 sysctl_sched_rt_runtime = old_runtime;
8614 } else {
8615 def_rt_bandwidth.rt_runtime = global_rt_runtime();
8616 def_rt_bandwidth.rt_period =
8617 ns_to_ktime(global_rt_period());
8618 }
8619 }
8620 mutex_unlock(&mutex);
8621
8622 return ret;
8623}
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008624
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008625#ifdef CONFIG_CGROUP_SCHED
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008626
8627/* return corresponding task_group object of a cgroup */
Paul Menage2b01dfe2007-10-24 18:23:50 +02008628static inline struct task_group *cgroup_tg(struct cgroup *cgrp)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008629{
Paul Menage2b01dfe2007-10-24 18:23:50 +02008630 return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id),
8631 struct task_group, css);
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008632}
8633
8634static struct cgroup_subsys_state *
Paul Menage2b01dfe2007-10-24 18:23:50 +02008635cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008636{
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008637 struct task_group *tg, *parent;
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008638
Paul Menage2b01dfe2007-10-24 18:23:50 +02008639 if (!cgrp->parent) {
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008640 /* This is early initialization for the top cgroup */
Paul Menage2b01dfe2007-10-24 18:23:50 +02008641 init_task_group.css.cgroup = cgrp;
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008642 return &init_task_group.css;
8643 }
8644
Dhaval Gianiec7dc8a2008-04-19 19:44:59 +02008645 parent = cgroup_tg(cgrp->parent);
8646 tg = sched_create_group(parent);
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008647 if (IS_ERR(tg))
8648 return ERR_PTR(-ENOMEM);
8649
8650 /* Bind the cgroup to task_group object we just created */
Paul Menage2b01dfe2007-10-24 18:23:50 +02008651 tg->css.cgroup = cgrp;
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008652
8653 return &tg->css;
8654}
8655
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01008656static void
8657cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008658{
Paul Menage2b01dfe2007-10-24 18:23:50 +02008659 struct task_group *tg = cgroup_tg(cgrp);
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008660
8661 sched_destroy_group(tg);
8662}
8663
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01008664static int
8665cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
8666 struct task_struct *tsk)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008667{
Peter Zijlstrab68aa232008-02-13 15:45:40 +01008668#ifdef CONFIG_RT_GROUP_SCHED
8669 /* Don't accept realtime tasks when there is no way for them to run */
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008670 if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
Peter Zijlstrab68aa232008-02-13 15:45:40 +01008671 return -EINVAL;
8672#else
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008673 /* We don't support RT-tasks being in separate groups */
8674 if (tsk->sched_class != &fair_sched_class)
8675 return -EINVAL;
Peter Zijlstrab68aa232008-02-13 15:45:40 +01008676#endif
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008677
8678 return 0;
8679}
8680
8681static void
Paul Menage2b01dfe2007-10-24 18:23:50 +02008682cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp,
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008683 struct cgroup *old_cont, struct task_struct *tsk)
8684{
8685 sched_move_task(tsk);
8686}
8687
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008688#ifdef CONFIG_FAIR_GROUP_SCHED
Paul Menagef4c753b2008-04-29 00:59:56 -07008689static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype,
Paul Menage2b01dfe2007-10-24 18:23:50 +02008690 u64 shareval)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008691{
Paul Menage2b01dfe2007-10-24 18:23:50 +02008692 return sched_group_set_shares(cgroup_tg(cgrp), shareval);
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008693}
8694
Paul Menagef4c753b2008-04-29 00:59:56 -07008695static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft)
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008696{
Paul Menage2b01dfe2007-10-24 18:23:50 +02008697 struct task_group *tg = cgroup_tg(cgrp);
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008698
8699 return (u64) tg->shares;
8700}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008701#endif /* CONFIG_FAIR_GROUP_SCHED */
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008702
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008703#ifdef CONFIG_RT_GROUP_SCHED
Mirco Tischler0c708142008-05-14 16:05:46 -07008704static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft,
Paul Menage06ecb272008-04-29 01:00:06 -07008705 s64 val)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008706{
Paul Menage06ecb272008-04-29 01:00:06 -07008707 return sched_group_set_rt_runtime(cgroup_tg(cgrp), val);
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008708}
8709
Paul Menage06ecb272008-04-29 01:00:06 -07008710static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft)
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008711{
Paul Menage06ecb272008-04-29 01:00:06 -07008712 return sched_group_rt_runtime(cgroup_tg(cgrp));
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008713}
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008714
8715static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype,
8716 u64 rt_period_us)
8717{
8718 return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us);
8719}
8720
8721static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft)
8722{
8723 return sched_group_rt_period(cgroup_tg(cgrp));
8724}
Dhaval Giani6d6bc0a2008-05-30 14:23:45 +02008725#endif /* CONFIG_RT_GROUP_SCHED */
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008726
Paul Menagefe5c7cc2007-10-29 21:18:11 +01008727static struct cftype cpu_files[] = {
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008728#ifdef CONFIG_FAIR_GROUP_SCHED
Paul Menagefe5c7cc2007-10-29 21:18:11 +01008729 {
8730 .name = "shares",
Paul Menagef4c753b2008-04-29 00:59:56 -07008731 .read_u64 = cpu_shares_read_u64,
8732 .write_u64 = cpu_shares_write_u64,
Paul Menagefe5c7cc2007-10-29 21:18:11 +01008733 },
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008734#endif
8735#ifdef CONFIG_RT_GROUP_SCHED
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008736 {
Peter Zijlstra9f0c1e52008-02-13 15:45:39 +01008737 .name = "rt_runtime_us",
Paul Menage06ecb272008-04-29 01:00:06 -07008738 .read_s64 = cpu_rt_runtime_read,
8739 .write_s64 = cpu_rt_runtime_write,
Peter Zijlstra6f505b12008-01-25 21:08:30 +01008740 },
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008741 {
8742 .name = "rt_period_us",
Paul Menagef4c753b2008-04-29 00:59:56 -07008743 .read_u64 = cpu_rt_period_read_uint,
8744 .write_u64 = cpu_rt_period_write_uint,
Peter Zijlstrad0b27fa2008-04-19 19:44:57 +02008745 },
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008746#endif
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008747};
8748
8749static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont)
8750{
Paul Menagefe5c7cc2007-10-29 21:18:11 +01008751 return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files));
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008752}
8753
8754struct cgroup_subsys cpu_cgroup_subsys = {
Ingo Molnar38605ca2007-10-29 21:18:11 +01008755 .name = "cpu",
8756 .create = cpu_cgroup_create,
8757 .destroy = cpu_cgroup_destroy,
8758 .can_attach = cpu_cgroup_can_attach,
8759 .attach = cpu_cgroup_attach,
8760 .populate = cpu_cgroup_populate,
8761 .subsys_id = cpu_cgroup_subsys_id,
Srivatsa Vaddagiri68318b82007-10-18 23:41:03 -07008762 .early_init = 1,
8763};
8764
Peter Zijlstra052f1dc2008-02-13 15:45:40 +01008765#endif /* CONFIG_CGROUP_SCHED */
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008766
8767#ifdef CONFIG_CGROUP_CPUACCT
8768
8769/*
8770 * CPU accounting code for task groups.
8771 *
8772 * Based on the work by Paul Menage (menage@google.com) and Balbir Singh
8773 * (balbir@in.ibm.com).
8774 */
8775
8776/* track cpu usage of a group of tasks */
8777struct cpuacct {
8778 struct cgroup_subsys_state css;
8779 /* cpuusage holds pointer to a u64-type object on every cpu */
8780 u64 *cpuusage;
8781};
8782
8783struct cgroup_subsys cpuacct_subsys;
8784
8785/* return cpu accounting group corresponding to this container */
Dhaval Giani32cd7562008-02-29 10:02:43 +05308786static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp)
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008787{
Dhaval Giani32cd7562008-02-29 10:02:43 +05308788 return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id),
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008789 struct cpuacct, css);
8790}
8791
8792/* return cpu accounting group to which this task belongs */
8793static inline struct cpuacct *task_ca(struct task_struct *tsk)
8794{
8795 return container_of(task_subsys_state(tsk, cpuacct_subsys_id),
8796 struct cpuacct, css);
8797}
8798
8799/* create a new cpu accounting group */
8800static struct cgroup_subsys_state *cpuacct_create(
Dhaval Giani32cd7562008-02-29 10:02:43 +05308801 struct cgroup_subsys *ss, struct cgroup *cgrp)
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008802{
8803 struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
8804
8805 if (!ca)
8806 return ERR_PTR(-ENOMEM);
8807
8808 ca->cpuusage = alloc_percpu(u64);
8809 if (!ca->cpuusage) {
8810 kfree(ca);
8811 return ERR_PTR(-ENOMEM);
8812 }
8813
8814 return &ca->css;
8815}
8816
8817/* destroy an existing cpu accounting group */
Ingo Molnar41a2d6c2007-12-05 15:46:09 +01008818static void
Dhaval Giani32cd7562008-02-29 10:02:43 +05308819cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008820{
Dhaval Giani32cd7562008-02-29 10:02:43 +05308821 struct cpuacct *ca = cgroup_ca(cgrp);
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008822
8823 free_percpu(ca->cpuusage);
8824 kfree(ca);
8825}
8826
8827/* return total cpu usage (in nanoseconds) of a group */
Dhaval Giani32cd7562008-02-29 10:02:43 +05308828static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft)
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008829{
Dhaval Giani32cd7562008-02-29 10:02:43 +05308830 struct cpuacct *ca = cgroup_ca(cgrp);
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008831 u64 totalcpuusage = 0;
8832 int i;
8833
8834 for_each_possible_cpu(i) {
8835 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
8836
8837 /*
8838 * Take rq->lock to make 64-bit addition safe on 32-bit
8839 * platforms.
8840 */
8841 spin_lock_irq(&cpu_rq(i)->lock);
8842 totalcpuusage += *cpuusage;
8843 spin_unlock_irq(&cpu_rq(i)->lock);
8844 }
8845
8846 return totalcpuusage;
8847}
8848
Dhaval Giani0297b802008-02-29 10:02:44 +05308849static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype,
8850 u64 reset)
8851{
8852 struct cpuacct *ca = cgroup_ca(cgrp);
8853 int err = 0;
8854 int i;
8855
8856 if (reset) {
8857 err = -EINVAL;
8858 goto out;
8859 }
8860
8861 for_each_possible_cpu(i) {
8862 u64 *cpuusage = percpu_ptr(ca->cpuusage, i);
8863
8864 spin_lock_irq(&cpu_rq(i)->lock);
8865 *cpuusage = 0;
8866 spin_unlock_irq(&cpu_rq(i)->lock);
8867 }
8868out:
8869 return err;
8870}
8871
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008872static struct cftype files[] = {
8873 {
8874 .name = "usage",
Paul Menagef4c753b2008-04-29 00:59:56 -07008875 .read_u64 = cpuusage_read,
8876 .write_u64 = cpuusage_write,
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008877 },
8878};
8879
Dhaval Giani32cd7562008-02-29 10:02:43 +05308880static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008881{
Dhaval Giani32cd7562008-02-29 10:02:43 +05308882 return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files));
Srivatsa Vaddagirid842de82007-12-02 20:04:49 +01008883}
8884
8885/*
8886 * charge this task's execution time to its accounting group.
8887 *
8888 * called with rq->lock held.
8889 */
8890static void cpuacct_charge(struct task_struct *tsk, u64 cputime)
8891{
8892 struct cpuacct *ca;
8893
8894 if (!cpuacct_subsys.active)
8895 return;
8896
8897 ca = task_ca(tsk);
8898 if (ca) {
8899 u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk));
8900
8901 *cpuusage += cputime;
8902 }
8903}
8904
8905struct cgroup_subsys cpuacct_subsys = {
8906 .name = "cpuacct",
8907 .create = cpuacct_create,
8908 .destroy = cpuacct_destroy,
8909 .populate = cpuacct_populate,
8910 .subsys_id = cpuacct_subsys_id,
8911};
8912#endif /* CONFIG_CGROUP_CPUACCT */