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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
Linus Torvalds1da177e2005-04-16 15:20:36 -070025 */
26
27#include <linux/mm.h>
28#include <linux/module.h>
29#include <linux/nmi.h>
30#include <linux/init.h>
Ingo Molnardff06c12007-07-09 18:52:00 +020031#include <linux/uaccess.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/highmem.h>
33#include <linux/smp_lock.h>
34#include <asm/mmu_context.h>
35#include <linux/interrupt.h>
Randy.Dunlapc59ede72006-01-11 12:17:46 -080036#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070037#include <linux/completion.h>
38#include <linux/kernel_stat.h>
Ingo Molnar9a11b49a2006-07-03 00:24:33 -070039#include <linux/debug_locks.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040#include <linux/security.h>
41#include <linux/notifier.h>
42#include <linux/profile.h>
Nigel Cunningham7dfb7102006-12-06 20:34:23 -080043#include <linux/freezer.h>
akpm@osdl.org198e2f12006-01-12 01:05:30 -080044#include <linux/vmalloc.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <linux/blkdev.h>
46#include <linux/delay.h>
47#include <linux/smp.h>
48#include <linux/threads.h>
49#include <linux/timer.h>
50#include <linux/rcupdate.h>
51#include <linux/cpu.h>
52#include <linux/cpuset.h>
53#include <linux/percpu.h>
54#include <linux/kthread.h>
55#include <linux/seq_file.h>
Nick Piggine692ab52007-07-26 13:40:43 +020056#include <linux/sysctl.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070057#include <linux/syscalls.h>
58#include <linux/times.h>
Jay Lan8f0ab512006-09-30 23:28:59 -070059#include <linux/tsacct_kern.h>
bibo maoc6fd91f2006-03-26 01:38:20 -080060#include <linux/kprobes.h>
Shailabh Nagar0ff92242006-07-14 00:24:37 -070061#include <linux/delayacct.h>
Eric Dumazet5517d862007-05-08 00:32:57 -070062#include <linux/reciprocal_div.h>
Ingo Molnardff06c12007-07-09 18:52:00 +020063#include <linux/unistd.h>
Jens Axboef5ff8422007-09-21 09:19:54 +020064#include <linux/pagemap.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070065
Eric Dumazet5517d862007-05-08 00:32:57 -070066#include <asm/tlb.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070067
68/*
Alexey Dobriyanb035b6d2007-02-10 01:45:10 -080069 * Scheduler clock - returns current time in nanosec units.
70 * This is default implementation.
71 * Architectures and sub-architectures can override this.
72 */
73unsigned long long __attribute__((weak)) sched_clock(void)
74{
75 return (unsigned long long)jiffies * (1000000000 / HZ);
76}
77
78/*
Linus Torvalds1da177e2005-04-16 15:20:36 -070079 * Convert user-nice values [ -20 ... 0 ... 19 ]
80 * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ],
81 * and back.
82 */
83#define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20)
84#define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20)
85#define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio)
86
87/*
88 * 'User priority' is the nice value converted to something we
89 * can work with better when scaling various scheduler parameters,
90 * it's a [ 0 ... 39 ] range.
91 */
92#define USER_PRIO(p) ((p)-MAX_RT_PRIO)
93#define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio)
94#define MAX_USER_PRIO (USER_PRIO(MAX_PRIO))
95
96/*
97 * Some helpers for converting nanosecond timing to jiffy resolution
98 */
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +020099#define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (1000000000 / HZ))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700100#define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ))
101
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
Eric Dumazet5517d862007-05-08 00:32:57 -0700113#ifdef CONFIG_SMP
114/*
115 * Divide a load by a sched group cpu_power : (load / sg->__cpu_power)
116 * Since cpu_power is a 'constant', we can use a reciprocal divide.
117 */
118static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load)
119{
120 return reciprocal_divide(load, sg->reciprocal_cpu_power);
121}
122
123/*
124 * Each time a sched group cpu_power is changed,
125 * we must compute its reciprocal value
126 */
127static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val)
128{
129 sg->__cpu_power += val;
130 sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power);
131}
132#endif
133
Ingo Molnare05606d2007-07-09 18:51:59 +0200134static inline int rt_policy(int policy)
135{
136 if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR))
137 return 1;
138 return 0;
139}
140
141static inline int task_has_rt_policy(struct task_struct *p)
142{
143 return rt_policy(p->policy);
144}
145
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146/*
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200147 * This is the priority-queue data structure of the RT scheduling class:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700148 */
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200149struct rt_prio_array {
150 DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */
151 struct list_head queue[MAX_RT_PRIO];
152};
Linus Torvalds1da177e2005-04-16 15:20:36 -0700153
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200154#ifdef CONFIG_FAIR_GROUP_SCHED
155
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200156struct cfs_rq;
157
158/* task group related information */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200159struct task_group {
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200160 /* schedulable entities of this group on each cpu */
161 struct sched_entity **se;
162 /* runqueue "owned" by this group on each cpu */
163 struct cfs_rq **cfs_rq;
164 unsigned long shares;
Dhaval Giani5cb350b2007-10-15 17:00:14 +0200165 /* spinlock to serialize modification to shares */
166 spinlock_t lock;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200167};
168
169/* Default task group's sched entity on each cpu */
170static DEFINE_PER_CPU(struct sched_entity, init_sched_entity);
171/* Default task group's cfs_rq on each cpu */
172static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp;
173
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200174static struct sched_entity *init_sched_entity_p[NR_CPUS];
175static struct cfs_rq *init_cfs_rq_p[NR_CPUS];
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200176
177/* Default task group.
Ingo Molnar3a252012007-10-15 17:00:12 +0200178 * Every task in system belong to this group at bootup.
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200179 */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200180struct task_group init_task_group = {
Ingo Molnar3a252012007-10-15 17:00:12 +0200181 .se = init_sched_entity_p,
182 .cfs_rq = init_cfs_rq_p,
183};
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200184
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200185#ifdef CONFIG_FAIR_USER_SCHED
Ingo Molnar3a252012007-10-15 17:00:12 +0200186# define INIT_TASK_GRP_LOAD 2*NICE_0_LOAD
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200187#else
Ingo Molnar3a252012007-10-15 17:00:12 +0200188# define INIT_TASK_GRP_LOAD NICE_0_LOAD
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200189#endif
190
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200191static int init_task_group_load = INIT_TASK_GRP_LOAD;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200192
193/* return group to which a task belongs */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200194static inline struct task_group *task_group(struct task_struct *p)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200195{
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200196 struct task_group *tg;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200197
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200198#ifdef CONFIG_FAIR_USER_SCHED
199 tg = p->user->tg;
200#else
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200201 tg = &init_task_group;
Srivatsa Vaddagiri24e377a2007-10-15 17:00:09 +0200202#endif
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200203
204 return tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200205}
206
207/* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */
208static inline void set_task_cfs_rq(struct task_struct *p)
209{
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200210 p->se.cfs_rq = task_group(p)->cfs_rq[task_cpu(p)];
211 p->se.parent = task_group(p)->se[task_cpu(p)];
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +0200212}
213
214#else
215
216static inline void set_task_cfs_rq(struct task_struct *p) { }
217
218#endif /* CONFIG_FAIR_GROUP_SCHED */
219
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200220/* CFS-related fields in a runqueue */
221struct cfs_rq {
222 struct load_weight load;
223 unsigned long nr_running;
224
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200225 u64 exec_clock;
Ingo Molnare9acbff2007-10-15 17:00:04 +0200226 u64 min_vruntime;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200227
228 struct rb_root tasks_timeline;
229 struct rb_node *rb_leftmost;
230 struct rb_node *rb_load_balance_curr;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200231 /* 'curr' points to currently running entity on this cfs_rq.
232 * It is set to NULL otherwise (i.e when none are currently running).
233 */
234 struct sched_entity *curr;
Peter Zijlstraddc97292007-10-15 17:00:10 +0200235
236 unsigned long nr_spread_over;
237
Ingo Molnar62160e32007-10-15 17:00:03 +0200238#ifdef CONFIG_FAIR_GROUP_SCHED
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200239 struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */
240
241 /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in
242 * a hierarchy). Non-leaf lrqs hold other higher schedulable entities
243 * (like users, containers etc.)
244 *
245 * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This
246 * list is used during load balance.
247 */
248 struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */
Ingo Molnar4cf86d72007-10-15 17:00:14 +0200249 struct task_group *tg; /* group that "owns" this runqueue */
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +0200250 struct rcu_head rcu;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200251#endif
252};
253
254/* Real-Time classes' related field in a runqueue: */
255struct rt_rq {
256 struct rt_prio_array active;
257 int rt_load_balance_idx;
258 struct list_head *rt_load_balance_head, *rt_load_balance_curr;
259};
260
261/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700262 * This is the main, per-CPU runqueue data structure.
263 *
264 * Locking rule: those places that want to lock multiple runqueues
265 * (such as the load balancing or the thread migration code), lock
266 * acquire operations must be ordered by ascending &runqueue.
267 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700268struct rq {
Ingo Molnard8016492007-10-18 21:32:55 +0200269 /* runqueue lock: */
270 spinlock_t lock;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700271
272 /*
273 * nr_running and cpu_load should be in the same cacheline because
274 * remote CPUs use both these fields when doing load calculation.
275 */
276 unsigned long nr_running;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200277 #define CPU_LOAD_IDX_MAX 5
278 unsigned long cpu_load[CPU_LOAD_IDX_MAX];
Siddha, Suresh Bbdecea32007-05-08 00:32:48 -0700279 unsigned char idle_at_tick;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -0700280#ifdef CONFIG_NO_HZ
281 unsigned char in_nohz_recently;
282#endif
Ingo Molnard8016492007-10-18 21:32:55 +0200283 /* capture load from *all* tasks on this cpu: */
284 struct load_weight load;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200285 unsigned long nr_load_updates;
286 u64 nr_switches;
287
288 struct cfs_rq cfs;
289#ifdef CONFIG_FAIR_GROUP_SCHED
Ingo Molnard8016492007-10-18 21:32:55 +0200290 /* list of leaf cfs_rq on this cpu: */
291 struct list_head leaf_cfs_rq_list;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292#endif
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200293 struct rt_rq rt;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294
295 /*
296 * This is part of a global counter where only the total sum
297 * over all CPUs matters. A task can increase this counter on
298 * one CPU and if it got migrated afterwards it may decrease
299 * it on another CPU. Always updated under the runqueue lock:
300 */
301 unsigned long nr_uninterruptible;
302
Ingo Molnar36c8b582006-07-03 00:25:41 -0700303 struct task_struct *curr, *idle;
Christoph Lameterc9819f42006-12-10 02:20:25 -0800304 unsigned long next_balance;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700305 struct mm_struct *prev_mm;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200306
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200307 u64 clock, prev_clock_raw;
308 s64 clock_max_delta;
309
310 unsigned int clock_warps, clock_overflows;
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200311 u64 idle_clock;
312 unsigned int clock_deep_idle_events;
Ingo Molnar529c7722007-08-10 23:05:11 +0200313 u64 tick_timestamp;
Ingo Molnar6aa645e2007-07-09 18:51:58 +0200314
Linus Torvalds1da177e2005-04-16 15:20:36 -0700315 atomic_t nr_iowait;
316
317#ifdef CONFIG_SMP
318 struct sched_domain *sd;
319
320 /* For active balancing */
321 int active_balance;
322 int push_cpu;
Ingo Molnard8016492007-10-18 21:32:55 +0200323 /* cpu of this runqueue: */
324 int cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700325
Ingo Molnar36c8b582006-07-03 00:25:41 -0700326 struct task_struct *migration_thread;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327 struct list_head migration_queue;
328#endif
329
330#ifdef CONFIG_SCHEDSTATS
331 /* latency stats */
332 struct sched_info rq_sched_info;
333
334 /* sys_sched_yield() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200335 unsigned int yld_exp_empty;
336 unsigned int yld_act_empty;
337 unsigned int yld_both_empty;
338 unsigned int yld_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339
340 /* schedule() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200341 unsigned int sched_switch;
342 unsigned int sched_count;
343 unsigned int sched_goidle;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344
345 /* try_to_wake_up() stats */
Ken Chen480b9432007-10-18 21:32:56 +0200346 unsigned int ttwu_count;
347 unsigned int ttwu_local;
Ingo Molnarb8efb562007-10-15 17:00:10 +0200348
349 /* BKL stats */
Ken Chen480b9432007-10-18 21:32:56 +0200350 unsigned int bkl_count;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351#endif
Ingo Molnarfcb99372006-07-03 00:25:10 -0700352 struct lock_class_key rq_lock_key;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700353};
354
Fenghua Yuf34e3b62007-07-19 01:48:13 -0700355static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
Gautham R Shenoy5be93612007-05-09 02:34:04 -0700356static DEFINE_MUTEX(sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357
Ingo Molnardd41f592007-07-09 18:51:59 +0200358static inline void check_preempt_curr(struct rq *rq, struct task_struct *p)
359{
360 rq->curr->sched_class->check_preempt_curr(rq, p);
361}
362
Christoph Lameter0a2966b2006-09-25 23:30:51 -0700363static inline int cpu_of(struct rq *rq)
364{
365#ifdef CONFIG_SMP
366 return rq->cpu;
367#else
368 return 0;
369#endif
370}
371
Nick Piggin674311d2005-06-25 14:57:27 -0700372/*
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200373 * Update the per-runqueue clock, as finegrained as the platform can give
374 * us, but without assuming monotonicity, etc.:
Ingo Molnar20d315d2007-07-09 18:51:58 +0200375 */
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200376static void __update_rq_clock(struct rq *rq)
Ingo Molnar20d315d2007-07-09 18:51:58 +0200377{
378 u64 prev_raw = rq->prev_clock_raw;
379 u64 now = sched_clock();
380 s64 delta = now - prev_raw;
381 u64 clock = rq->clock;
382
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200383#ifdef CONFIG_SCHED_DEBUG
384 WARN_ON_ONCE(cpu_of(rq) != smp_processor_id());
385#endif
Ingo Molnar20d315d2007-07-09 18:51:58 +0200386 /*
387 * Protect against sched_clock() occasionally going backwards:
388 */
389 if (unlikely(delta < 0)) {
390 clock++;
391 rq->clock_warps++;
392 } else {
393 /*
394 * Catch too large forward jumps too:
395 */
Ingo Molnar529c7722007-08-10 23:05:11 +0200396 if (unlikely(clock + delta > rq->tick_timestamp + TICK_NSEC)) {
397 if (clock < rq->tick_timestamp + TICK_NSEC)
398 clock = rq->tick_timestamp + TICK_NSEC;
399 else
400 clock++;
Ingo Molnar20d315d2007-07-09 18:51:58 +0200401 rq->clock_overflows++;
402 } else {
403 if (unlikely(delta > rq->clock_max_delta))
404 rq->clock_max_delta = delta;
405 clock += delta;
406 }
407 }
408
409 rq->prev_clock_raw = now;
410 rq->clock = clock;
Ingo Molnar20d315d2007-07-09 18:51:58 +0200411}
412
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200413static void update_rq_clock(struct rq *rq)
Ingo Molnar20d315d2007-07-09 18:51:58 +0200414{
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200415 if (likely(smp_processor_id() == cpu_of(rq)))
416 __update_rq_clock(rq);
417}
Ingo Molnar20d315d2007-07-09 18:51:58 +0200418
Ingo Molnar20d315d2007-07-09 18:51:58 +0200419/*
Nick Piggin674311d2005-06-25 14:57:27 -0700420 * The domain tree (rq->sd) is protected by RCU's quiescent state transition.
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -0700421 * See detach_destroy_domains: synchronize_sched for details.
Nick Piggin674311d2005-06-25 14:57:27 -0700422 *
423 * The domain tree of any CPU may only be accessed from within
424 * preempt-disabled sections.
425 */
Ingo Molnar48f24c42006-07-03 00:25:40 -0700426#define for_each_domain(cpu, __sd) \
427 for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700428
429#define cpu_rq(cpu) (&per_cpu(runqueues, (cpu)))
430#define this_rq() (&__get_cpu_var(runqueues))
431#define task_rq(p) cpu_rq(task_cpu(p))
432#define cpu_curr(cpu) (cpu_rq(cpu)->curr)
433
Ingo Molnare436d802007-07-19 21:28:35 +0200434/*
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200435 * Tunables that become constants when CONFIG_SCHED_DEBUG is off:
436 */
437#ifdef CONFIG_SCHED_DEBUG
438# define const_debug __read_mostly
439#else
440# define const_debug static const
441#endif
442
443/*
444 * Debugging: various feature bits
445 */
446enum {
Ingo Molnarbbdba7c2007-10-15 17:00:06 +0200447 SCHED_FEAT_NEW_FAIR_SLEEPERS = 1,
448 SCHED_FEAT_START_DEBIT = 2,
Ingo Molnar06877c32007-10-15 17:00:13 +0200449 SCHED_FEAT_TREE_AVG = 4,
Ingo Molnarbbdba7c2007-10-15 17:00:06 +0200450 SCHED_FEAT_APPROX_AVG = 8,
Peter Zijlstrace6c1312007-10-15 17:00:14 +0200451 SCHED_FEAT_WAKEUP_PREEMPT = 16,
Mike Galbraith95938a32007-10-15 17:00:14 +0200452 SCHED_FEAT_PREEMPT_RESTRICT = 32,
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200453};
454
455const_debug unsigned int sysctl_sched_features =
Ingo Molnar8401f772007-10-18 21:32:55 +0200456 SCHED_FEAT_NEW_FAIR_SLEEPERS * 1 |
457 SCHED_FEAT_START_DEBIT * 1 |
458 SCHED_FEAT_TREE_AVG * 0 |
459 SCHED_FEAT_APPROX_AVG * 0 |
460 SCHED_FEAT_WAKEUP_PREEMPT * 1 |
461 SCHED_FEAT_PREEMPT_RESTRICT * 1;
Ingo Molnarbf5c91b2007-10-15 17:00:04 +0200462
463#define sched_feat(x) (sysctl_sched_features & SCHED_FEAT_##x)
464
465/*
Ingo Molnare436d802007-07-19 21:28:35 +0200466 * For kernel-internal use: high-speed (but slightly incorrect) per-cpu
467 * clock constructed from sched_clock():
468 */
469unsigned long long cpu_clock(int cpu)
470{
Ingo Molnare436d802007-07-19 21:28:35 +0200471 unsigned long long now;
472 unsigned long flags;
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200473 struct rq *rq;
Ingo Molnare436d802007-07-19 21:28:35 +0200474
Ingo Molnar2cd4d0e2007-07-26 13:40:43 +0200475 local_irq_save(flags);
Ingo Molnarb04a0f42007-08-09 11:16:46 +0200476 rq = cpu_rq(cpu);
477 update_rq_clock(rq);
478 now = rq->clock;
Ingo Molnar2cd4d0e2007-07-26 13:40:43 +0200479 local_irq_restore(flags);
Ingo Molnare436d802007-07-19 21:28:35 +0200480
481 return now;
482}
Paul E. McKenneya58f6f22007-10-15 17:00:14 +0200483EXPORT_SYMBOL_GPL(cpu_clock);
Ingo Molnare436d802007-07-19 21:28:35 +0200484
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485#ifndef prepare_arch_switch
Nick Piggin4866cde2005-06-25 14:57:23 -0700486# define prepare_arch_switch(next) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700487#endif
Nick Piggin4866cde2005-06-25 14:57:23 -0700488#ifndef finish_arch_switch
489# define finish_arch_switch(prev) do { } while (0)
490#endif
491
492#ifndef __ARCH_WANT_UNLOCKED_CTXSW
Ingo Molnar70b97a72006-07-03 00:25:42 -0700493static inline int task_running(struct rq *rq, struct task_struct *p)
Nick Piggin4866cde2005-06-25 14:57:23 -0700494{
495 return rq->curr == p;
496}
497
Ingo Molnar70b97a72006-07-03 00:25:42 -0700498static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -0700499{
500}
501
Ingo Molnar70b97a72006-07-03 00:25:42 -0700502static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
Nick Piggin4866cde2005-06-25 14:57:23 -0700503{
Ingo Molnarda04c032005-09-13 11:17:59 +0200504#ifdef CONFIG_DEBUG_SPINLOCK
505 /* this is a valid case when another task releases the spinlock */
506 rq->lock.owner = current;
507#endif
Ingo Molnar8a25d5d2006-07-03 00:24:54 -0700508 /*
509 * If we are tracking spinlock dependencies then we have to
510 * fix up the runqueue lock - which gets 'carried over' from
511 * prev into current:
512 */
513 spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_);
514
Nick Piggin4866cde2005-06-25 14:57:23 -0700515 spin_unlock_irq(&rq->lock);
516}
517
518#else /* __ARCH_WANT_UNLOCKED_CTXSW */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700519static inline int task_running(struct rq *rq, struct task_struct *p)
Nick Piggin4866cde2005-06-25 14:57:23 -0700520{
521#ifdef CONFIG_SMP
522 return p->oncpu;
523#else
524 return rq->curr == p;
525#endif
526}
527
Ingo Molnar70b97a72006-07-03 00:25:42 -0700528static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -0700529{
530#ifdef CONFIG_SMP
531 /*
532 * We can optimise this out completely for !SMP, because the
533 * SMP rebalancing from interrupt is the only thing that cares
534 * here.
535 */
536 next->oncpu = 1;
537#endif
538#ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW
539 spin_unlock_irq(&rq->lock);
540#else
541 spin_unlock(&rq->lock);
542#endif
543}
544
Ingo Molnar70b97a72006-07-03 00:25:42 -0700545static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev)
Nick Piggin4866cde2005-06-25 14:57:23 -0700546{
547#ifdef CONFIG_SMP
548 /*
549 * After ->oncpu is cleared, the task can be moved to a different CPU.
550 * We must ensure this doesn't happen until the switch is completely
551 * finished.
552 */
553 smp_wmb();
554 prev->oncpu = 0;
555#endif
556#ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW
557 local_irq_enable();
558#endif
559}
560#endif /* __ARCH_WANT_UNLOCKED_CTXSW */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561
562/*
Ingo Molnarb29739f2006-06-27 02:54:51 -0700563 * __task_rq_lock - lock the runqueue a given task resides on.
564 * Must be called interrupts disabled.
565 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700566static inline struct rq *__task_rq_lock(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700567 __acquires(rq->lock)
568{
Andi Kleen3a5c3592007-10-15 17:00:14 +0200569 for (;;) {
570 struct rq *rq = task_rq(p);
571 spin_lock(&rq->lock);
572 if (likely(rq == task_rq(p)))
573 return rq;
Ingo Molnarb29739f2006-06-27 02:54:51 -0700574 spin_unlock(&rq->lock);
Ingo Molnarb29739f2006-06-27 02:54:51 -0700575 }
Ingo Molnarb29739f2006-06-27 02:54:51 -0700576}
577
578/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700579 * task_rq_lock - lock the runqueue a given task resides on and disable
580 * interrupts. Note the ordering: we can safely lookup the task_rq without
581 * explicitly disabling preemption.
582 */
Ingo Molnar70b97a72006-07-03 00:25:42 -0700583static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700584 __acquires(rq->lock)
585{
Ingo Molnar70b97a72006-07-03 00:25:42 -0700586 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700587
Andi Kleen3a5c3592007-10-15 17:00:14 +0200588 for (;;) {
589 local_irq_save(*flags);
590 rq = task_rq(p);
591 spin_lock(&rq->lock);
592 if (likely(rq == task_rq(p)))
593 return rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700594 spin_unlock_irqrestore(&rq->lock, *flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700595 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596}
597
Alexey Dobriyana9957442007-10-15 17:00:13 +0200598static void __task_rq_unlock(struct rq *rq)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700599 __releases(rq->lock)
600{
601 spin_unlock(&rq->lock);
602}
603
Ingo Molnar70b97a72006-07-03 00:25:42 -0700604static inline void task_rq_unlock(struct rq *rq, unsigned long *flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700605 __releases(rq->lock)
606{
607 spin_unlock_irqrestore(&rq->lock, *flags);
608}
609
Linus Torvalds1da177e2005-04-16 15:20:36 -0700610/*
Robert P. J. Daycc2a73b2006-12-10 02:20:00 -0800611 * this_rq_lock - lock this runqueue and disable interrupts.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700612 */
Alexey Dobriyana9957442007-10-15 17:00:13 +0200613static struct rq *this_rq_lock(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700614 __acquires(rq->lock)
615{
Ingo Molnar70b97a72006-07-03 00:25:42 -0700616 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617
618 local_irq_disable();
619 rq = this_rq();
620 spin_lock(&rq->lock);
621
622 return rq;
623}
624
Ingo Molnarc24d20d2007-07-09 18:51:59 +0200625/*
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200626 * We are going deep-idle (irqs are disabled):
Ingo Molnar1b9f19c2007-07-09 18:51:59 +0200627 */
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200628void sched_clock_idle_sleep_event(void)
Ingo Molnar1b9f19c2007-07-09 18:51:59 +0200629{
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200630 struct rq *rq = cpu_rq(smp_processor_id());
Ingo Molnar1b9f19c2007-07-09 18:51:59 +0200631
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200632 spin_lock(&rq->lock);
633 __update_rq_clock(rq);
634 spin_unlock(&rq->lock);
635 rq->clock_deep_idle_events++;
Ingo Molnar1b9f19c2007-07-09 18:51:59 +0200636}
Ingo Molnar2aa44d02007-08-23 15:18:02 +0200637EXPORT_SYMBOL_GPL(sched_clock_idle_sleep_event);
638
639/*
640 * We just idled delta nanoseconds (called with irqs disabled):
641 */
642void sched_clock_idle_wakeup_event(u64 delta_ns)
643{
644 struct rq *rq = cpu_rq(smp_processor_id());
645 u64 now = sched_clock();
646
647 rq->idle_clock += delta_ns;
648 /*
649 * Override the previous timestamp and ignore all
650 * sched_clock() deltas that occured while we idled,
651 * and use the PM-provided delta_ns to advance the
652 * rq clock:
653 */
654 spin_lock(&rq->lock);
655 rq->prev_clock_raw = now;
656 rq->clock += delta_ns;
657 spin_unlock(&rq->lock);
658}
659EXPORT_SYMBOL_GPL(sched_clock_idle_wakeup_event);
Ingo Molnar1b9f19c2007-07-09 18:51:59 +0200660
661/*
Ingo Molnarc24d20d2007-07-09 18:51:59 +0200662 * resched_task - mark a task 'to be rescheduled now'.
663 *
664 * On UP this means the setting of the need_resched flag, on SMP it
665 * might also involve a cross-CPU call to trigger the scheduler on
666 * the target CPU.
667 */
668#ifdef CONFIG_SMP
669
670#ifndef tsk_is_polling
671#define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG)
672#endif
673
674static void resched_task(struct task_struct *p)
675{
676 int cpu;
677
678 assert_spin_locked(&task_rq(p)->lock);
679
680 if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
681 return;
682
683 set_tsk_thread_flag(p, TIF_NEED_RESCHED);
684
685 cpu = task_cpu(p);
686 if (cpu == smp_processor_id())
687 return;
688
689 /* NEED_RESCHED must be visible before we test polling */
690 smp_mb();
691 if (!tsk_is_polling(p))
692 smp_send_reschedule(cpu);
693}
694
695static void resched_cpu(int cpu)
696{
697 struct rq *rq = cpu_rq(cpu);
698 unsigned long flags;
699
700 if (!spin_trylock_irqsave(&rq->lock, flags))
701 return;
702 resched_task(cpu_curr(cpu));
703 spin_unlock_irqrestore(&rq->lock, flags);
704}
705#else
706static inline void resched_task(struct task_struct *p)
707{
708 assert_spin_locked(&task_rq(p)->lock);
709 set_tsk_need_resched(p);
710}
711#endif
712
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200713#if BITS_PER_LONG == 32
714# define WMULT_CONST (~0UL)
715#else
716# define WMULT_CONST (1UL << 32)
717#endif
718
719#define WMULT_SHIFT 32
720
Ingo Molnar194081e2007-08-09 11:16:51 +0200721/*
722 * Shift right and round:
723 */
Ingo Molnarcf2ab462007-09-05 14:32:49 +0200724#define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y))
Ingo Molnar194081e2007-08-09 11:16:51 +0200725
Ingo Molnarcb1c4fc2007-08-02 17:41:40 +0200726static unsigned long
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200727calc_delta_mine(unsigned long delta_exec, unsigned long weight,
728 struct load_weight *lw)
729{
730 u64 tmp;
731
732 if (unlikely(!lw->inv_weight))
Ingo Molnar194081e2007-08-09 11:16:51 +0200733 lw->inv_weight = (WMULT_CONST - lw->weight/2) / lw->weight + 1;
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200734
735 tmp = (u64)delta_exec * weight;
736 /*
737 * Check whether we'd overflow the 64-bit multiplication:
738 */
Ingo Molnar194081e2007-08-09 11:16:51 +0200739 if (unlikely(tmp > WMULT_CONST))
Ingo Molnarcf2ab462007-09-05 14:32:49 +0200740 tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight,
Ingo Molnar194081e2007-08-09 11:16:51 +0200741 WMULT_SHIFT/2);
742 else
Ingo Molnarcf2ab462007-09-05 14:32:49 +0200743 tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT);
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200744
Ingo Molnarecf691d2007-08-02 17:41:40 +0200745 return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX);
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200746}
747
748static inline unsigned long
749calc_delta_fair(unsigned long delta_exec, struct load_weight *lw)
750{
751 return calc_delta_mine(delta_exec, NICE_0_LOAD, lw);
752}
753
Ingo Molnar10919852007-10-15 17:00:04 +0200754static inline void update_load_add(struct load_weight *lw, unsigned long inc)
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200755{
756 lw->weight += inc;
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200757}
758
Ingo Molnar10919852007-10-15 17:00:04 +0200759static inline void update_load_sub(struct load_weight *lw, unsigned long dec)
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200760{
761 lw->weight -= dec;
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200762}
763
Linus Torvalds1da177e2005-04-16 15:20:36 -0700764/*
Peter Williams2dd73a42006-06-27 02:54:34 -0700765 * To aid in avoiding the subversion of "niceness" due to uneven distribution
766 * of tasks with abnormal "nice" values across CPUs the contribution that
767 * each task makes to its run queue's load is weighted according to its
768 * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a
769 * scaled version of the new time slice allocation that they receive on time
770 * slice expiry etc.
771 */
772
Ingo Molnardd41f592007-07-09 18:51:59 +0200773#define WEIGHT_IDLEPRIO 2
774#define WMULT_IDLEPRIO (1 << 31)
775
776/*
777 * Nice levels are multiplicative, with a gentle 10% change for every
778 * nice level changed. I.e. when a CPU-bound task goes from nice 0 to
779 * nice 1, it will get ~10% less CPU time than another CPU-bound task
780 * that remained on nice 0.
781 *
782 * The "10% effect" is relative and cumulative: from _any_ nice level,
783 * if you go up 1 level, it's -10% CPU usage, if you go down 1 level
Ingo Molnarf9153ee2007-07-16 09:46:30 +0200784 * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25.
785 * If a task goes up by ~10% and another task goes down by ~10% then
786 * the relative distance between them is ~25%.)
Ingo Molnardd41f592007-07-09 18:51:59 +0200787 */
788static const int prio_to_weight[40] = {
Ingo Molnar254753d2007-08-09 11:16:51 +0200789 /* -20 */ 88761, 71755, 56483, 46273, 36291,
790 /* -15 */ 29154, 23254, 18705, 14949, 11916,
791 /* -10 */ 9548, 7620, 6100, 4904, 3906,
792 /* -5 */ 3121, 2501, 1991, 1586, 1277,
793 /* 0 */ 1024, 820, 655, 526, 423,
794 /* 5 */ 335, 272, 215, 172, 137,
795 /* 10 */ 110, 87, 70, 56, 45,
796 /* 15 */ 36, 29, 23, 18, 15,
Ingo Molnardd41f592007-07-09 18:51:59 +0200797};
798
Ingo Molnar5714d2d2007-07-16 09:46:31 +0200799/*
800 * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated.
801 *
802 * In cases where the weight does not change often, we can use the
803 * precalculated inverse to speed up arithmetics by turning divisions
804 * into multiplications:
805 */
Ingo Molnardd41f592007-07-09 18:51:59 +0200806static const u32 prio_to_wmult[40] = {
Ingo Molnar254753d2007-08-09 11:16:51 +0200807 /* -20 */ 48388, 59856, 76040, 92818, 118348,
808 /* -15 */ 147320, 184698, 229616, 287308, 360437,
809 /* -10 */ 449829, 563644, 704093, 875809, 1099582,
810 /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326,
811 /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587,
812 /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126,
813 /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717,
814 /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153,
Ingo Molnardd41f592007-07-09 18:51:59 +0200815};
Peter Williams2dd73a42006-06-27 02:54:34 -0700816
Ingo Molnardd41f592007-07-09 18:51:59 +0200817static void activate_task(struct rq *rq, struct task_struct *p, int wakeup);
818
819/*
820 * runqueue iterator, to support SMP load-balancing between different
821 * scheduling classes, without having to expose their internal data
822 * structures to the load-balancing proper:
823 */
824struct rq_iterator {
825 void *arg;
826 struct task_struct *(*start)(void *);
827 struct task_struct *(*next)(void *);
828};
829
830static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
831 unsigned long max_nr_move, unsigned long max_load_move,
832 struct sched_domain *sd, enum cpu_idle_type idle,
833 int *all_pinned, unsigned long *load_moved,
Peter Williamsa4ac01c2007-08-09 11:16:46 +0200834 int *this_best_prio, struct rq_iterator *iterator);
Ingo Molnardd41f592007-07-09 18:51:59 +0200835
836#include "sched_stats.h"
Ingo Molnardd41f592007-07-09 18:51:59 +0200837#include "sched_idletask.c"
Ingo Molnar5522d5d2007-10-15 17:00:12 +0200838#include "sched_fair.c"
839#include "sched_rt.c"
Ingo Molnardd41f592007-07-09 18:51:59 +0200840#ifdef CONFIG_SCHED_DEBUG
841# include "sched_debug.c"
842#endif
843
844#define sched_class_highest (&rt_sched_class)
845
Ingo Molnar9c217242007-08-02 17:41:40 +0200846/*
847 * Update delta_exec, delta_fair fields for rq.
848 *
849 * delta_fair clock advances at a rate inversely proportional to
Dmitry Adamushko495eca42007-10-15 17:00:06 +0200850 * total load (rq->load.weight) on the runqueue, while
Ingo Molnar9c217242007-08-02 17:41:40 +0200851 * delta_exec advances at the same rate as wall-clock (provided
852 * cpu is not idle).
853 *
854 * delta_exec / delta_fair is a measure of the (smoothened) load on this
855 * runqueue over any given interval. This (smoothened) load is used
856 * during load balance.
857 *
Dmitry Adamushko495eca42007-10-15 17:00:06 +0200858 * This function is called /before/ updating rq->load
Ingo Molnar9c217242007-08-02 17:41:40 +0200859 * and when switching tasks.
860 */
Ingo Molnar29b4b622007-08-09 11:16:49 +0200861static inline void inc_load(struct rq *rq, const struct task_struct *p)
Ingo Molnar9c217242007-08-02 17:41:40 +0200862{
Dmitry Adamushko495eca42007-10-15 17:00:06 +0200863 update_load_add(&rq->load, p->se.load.weight);
Ingo Molnar9c217242007-08-02 17:41:40 +0200864}
865
Ingo Molnar79b5ddd2007-08-09 11:16:49 +0200866static inline void dec_load(struct rq *rq, const struct task_struct *p)
Ingo Molnar9c217242007-08-02 17:41:40 +0200867{
Dmitry Adamushko495eca42007-10-15 17:00:06 +0200868 update_load_sub(&rq->load, p->se.load.weight);
Ingo Molnar9c217242007-08-02 17:41:40 +0200869}
870
Ingo Molnare5fa2232007-08-09 11:16:49 +0200871static void inc_nr_running(struct task_struct *p, struct rq *rq)
Ingo Molnar9c217242007-08-02 17:41:40 +0200872{
873 rq->nr_running++;
Ingo Molnar29b4b622007-08-09 11:16:49 +0200874 inc_load(rq, p);
Ingo Molnar9c217242007-08-02 17:41:40 +0200875}
876
Ingo Molnardb531812007-08-09 11:16:49 +0200877static void dec_nr_running(struct task_struct *p, struct rq *rq)
Ingo Molnar9c217242007-08-02 17:41:40 +0200878{
879 rq->nr_running--;
Ingo Molnar79b5ddd2007-08-09 11:16:49 +0200880 dec_load(rq, p);
Ingo Molnar9c217242007-08-02 17:41:40 +0200881}
882
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200883static void set_load_weight(struct task_struct *p)
884{
885 if (task_has_rt_policy(p)) {
Ingo Molnardd41f592007-07-09 18:51:59 +0200886 p->se.load.weight = prio_to_weight[0] * 2;
887 p->se.load.inv_weight = prio_to_wmult[0] >> 1;
888 return;
889 }
890
891 /*
892 * SCHED_IDLE tasks get minimal weight:
893 */
894 if (p->policy == SCHED_IDLE) {
895 p->se.load.weight = WEIGHT_IDLEPRIO;
896 p->se.load.inv_weight = WMULT_IDLEPRIO;
897 return;
898 }
899
900 p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO];
901 p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO];
Ingo Molnar45bf76d2007-07-09 18:51:59 +0200902}
903
Ingo Molnar8159f872007-08-09 11:16:49 +0200904static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
Ingo Molnar71f8bd42007-07-09 18:51:59 +0200905{
906 sched_info_queued(p);
Ingo Molnarfd390f62007-08-09 11:16:48 +0200907 p->sched_class->enqueue_task(rq, p, wakeup);
Ingo Molnardd41f592007-07-09 18:51:59 +0200908 p->se.on_rq = 1;
909}
910
Ingo Molnar69be72c2007-08-09 11:16:49 +0200911static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
Ingo Molnardd41f592007-07-09 18:51:59 +0200912{
Ingo Molnarf02231e2007-08-09 11:16:48 +0200913 p->sched_class->dequeue_task(rq, p, sleep);
Ingo Molnardd41f592007-07-09 18:51:59 +0200914 p->se.on_rq = 0;
Ingo Molnar71f8bd42007-07-09 18:51:59 +0200915}
916
917/*
Ingo Molnardd41f592007-07-09 18:51:59 +0200918 * __normal_prio - return the priority that is based on the static prio
Ingo Molnar71f8bd42007-07-09 18:51:59 +0200919 */
Ingo Molnar14531182007-07-09 18:51:59 +0200920static inline int __normal_prio(struct task_struct *p)
921{
Ingo Molnardd41f592007-07-09 18:51:59 +0200922 return p->static_prio;
Ingo Molnar14531182007-07-09 18:51:59 +0200923}
924
925/*
Ingo Molnarb29739f2006-06-27 02:54:51 -0700926 * Calculate the expected normal priority: i.e. priority
927 * without taking RT-inheritance into account. Might be
928 * boosted by interactivity modifiers. Changes upon fork,
929 * setprio syscalls, and whenever the interactivity
930 * estimator recalculates.
931 */
Ingo Molnar36c8b582006-07-03 00:25:41 -0700932static inline int normal_prio(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700933{
934 int prio;
935
Ingo Molnare05606d2007-07-09 18:51:59 +0200936 if (task_has_rt_policy(p))
Ingo Molnarb29739f2006-06-27 02:54:51 -0700937 prio = MAX_RT_PRIO-1 - p->rt_priority;
938 else
939 prio = __normal_prio(p);
940 return prio;
941}
942
943/*
944 * Calculate the current priority, i.e. the priority
945 * taken into account by the scheduler. This value might
946 * be boosted by RT tasks, or might be boosted by
947 * interactivity modifiers. Will be RT if the task got
948 * RT-boosted. If not then it returns p->normal_prio.
949 */
Ingo Molnar36c8b582006-07-03 00:25:41 -0700950static int effective_prio(struct task_struct *p)
Ingo Molnarb29739f2006-06-27 02:54:51 -0700951{
952 p->normal_prio = normal_prio(p);
953 /*
954 * If we are RT tasks or we were boosted to RT priority,
955 * keep the priority unchanged. Otherwise, update priority
956 * to the normal priority:
957 */
958 if (!rt_prio(p->prio))
959 return p->normal_prio;
960 return p->prio;
961}
962
963/*
Ingo Molnardd41f592007-07-09 18:51:59 +0200964 * activate_task - move a task to the runqueue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700965 */
Ingo Molnardd41f592007-07-09 18:51:59 +0200966static void activate_task(struct rq *rq, struct task_struct *p, int wakeup)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700967{
Ingo Molnardd41f592007-07-09 18:51:59 +0200968 if (p->state == TASK_UNINTERRUPTIBLE)
969 rq->nr_uninterruptible--;
970
Ingo Molnar8159f872007-08-09 11:16:49 +0200971 enqueue_task(rq, p, wakeup);
Ingo Molnare5fa2232007-08-09 11:16:49 +0200972 inc_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700973}
974
975/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700976 * deactivate_task - remove a task from the runqueue.
977 */
Ingo Molnar2e1cb742007-08-09 11:16:49 +0200978static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700979{
Ingo Molnardd41f592007-07-09 18:51:59 +0200980 if (p->state == TASK_UNINTERRUPTIBLE)
981 rq->nr_uninterruptible++;
982
Ingo Molnar69be72c2007-08-09 11:16:49 +0200983 dequeue_task(rq, p, sleep);
Ingo Molnardb531812007-08-09 11:16:49 +0200984 dec_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700985}
986
Linus Torvalds1da177e2005-04-16 15:20:36 -0700987/**
988 * task_curr - is this task currently executing on a CPU?
989 * @p: the task in question.
990 */
Ingo Molnar36c8b582006-07-03 00:25:41 -0700991inline int task_curr(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700992{
993 return cpu_curr(task_cpu(p)) == p;
994}
995
Peter Williams2dd73a42006-06-27 02:54:34 -0700996/* Used instead of source_load when we know the type == 0 */
997unsigned long weighted_cpuload(const int cpu)
998{
Dmitry Adamushko495eca42007-10-15 17:00:06 +0200999 return cpu_rq(cpu)->load.weight;
Ingo Molnardd41f592007-07-09 18:51:59 +02001000}
1001
1002static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
1003{
1004#ifdef CONFIG_SMP
1005 task_thread_info(p)->cpu = cpu;
Ingo Molnardd41f592007-07-09 18:51:59 +02001006#endif
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02001007 set_task_cfs_rq(p);
Peter Williams2dd73a42006-06-27 02:54:34 -07001008}
1009
Linus Torvalds1da177e2005-04-16 15:20:36 -07001010#ifdef CONFIG_SMP
Ingo Molnarc65cc872007-07-09 18:51:58 +02001011
Ingo Molnarcc367732007-10-15 17:00:18 +02001012/*
1013 * Is this task likely cache-hot:
1014 */
1015static inline int
1016task_hot(struct task_struct *p, u64 now, struct sched_domain *sd)
1017{
1018 s64 delta;
1019
1020 if (p->sched_class != &fair_sched_class)
1021 return 0;
1022
Ingo Molnar6bc16652007-10-15 17:00:18 +02001023 if (sysctl_sched_migration_cost == -1)
1024 return 1;
1025 if (sysctl_sched_migration_cost == 0)
1026 return 0;
1027
Ingo Molnarcc367732007-10-15 17:00:18 +02001028 delta = now - p->se.exec_start;
1029
1030 return delta < (s64)sysctl_sched_migration_cost;
1031}
1032
1033
Ingo Molnardd41f592007-07-09 18:51:59 +02001034void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
Ingo Molnarc65cc872007-07-09 18:51:58 +02001035{
Ingo Molnardd41f592007-07-09 18:51:59 +02001036 int old_cpu = task_cpu(p);
1037 struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu);
Srivatsa Vaddagiri2830cf82007-10-15 17:00:12 +02001038 struct cfs_rq *old_cfsrq = task_cfs_rq(p),
1039 *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu);
Ingo Molnarbbdba7c2007-10-15 17:00:06 +02001040 u64 clock_offset;
Ingo Molnardd41f592007-07-09 18:51:59 +02001041
1042 clock_offset = old_rq->clock - new_rq->clock;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001043
1044#ifdef CONFIG_SCHEDSTATS
1045 if (p->se.wait_start)
1046 p->se.wait_start -= clock_offset;
Ingo Molnardd41f592007-07-09 18:51:59 +02001047 if (p->se.sleep_start)
1048 p->se.sleep_start -= clock_offset;
1049 if (p->se.block_start)
1050 p->se.block_start -= clock_offset;
Ingo Molnarcc367732007-10-15 17:00:18 +02001051 if (old_cpu != new_cpu) {
1052 schedstat_inc(p, se.nr_migrations);
1053 if (task_hot(p, old_rq->clock, NULL))
1054 schedstat_inc(p, se.nr_forced2_migrations);
1055 }
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001056#endif
Srivatsa Vaddagiri2830cf82007-10-15 17:00:12 +02001057 p->se.vruntime -= old_cfsrq->min_vruntime -
1058 new_cfsrq->min_vruntime;
Ingo Molnardd41f592007-07-09 18:51:59 +02001059
1060 __set_task_cpu(p, new_cpu);
Ingo Molnarc65cc872007-07-09 18:51:58 +02001061}
1062
Ingo Molnar70b97a72006-07-03 00:25:42 -07001063struct migration_req {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064 struct list_head list;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001065
Ingo Molnar36c8b582006-07-03 00:25:41 -07001066 struct task_struct *task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001067 int dest_cpu;
1068
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069 struct completion done;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001070};
Linus Torvalds1da177e2005-04-16 15:20:36 -07001071
1072/*
1073 * The task's runqueue lock must be held.
1074 * Returns true if you have to wait for migration thread.
1075 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001076static int
Ingo Molnar70b97a72006-07-03 00:25:42 -07001077migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001078{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001079 struct rq *rq = task_rq(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001080
1081 /*
1082 * If the task is not on a runqueue (and not running), then
1083 * it is sufficient to simply update the task's cpu field.
1084 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001085 if (!p->se.on_rq && !task_running(rq, p)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001086 set_task_cpu(p, dest_cpu);
1087 return 0;
1088 }
1089
1090 init_completion(&req->done);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001091 req->task = p;
1092 req->dest_cpu = dest_cpu;
1093 list_add(&req->list, &rq->migration_queue);
Ingo Molnar48f24c42006-07-03 00:25:40 -07001094
Linus Torvalds1da177e2005-04-16 15:20:36 -07001095 return 1;
1096}
1097
1098/*
1099 * wait_task_inactive - wait for a thread to unschedule.
1100 *
1101 * The caller must ensure that the task *will* unschedule sometime soon,
1102 * else this function might spin for a *long* time. This function can't
1103 * be called with interrupts off, or it may introduce deadlock with
1104 * smp_call_function() if an IPI is sent by the same process we are
1105 * waiting to become inactive.
1106 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001107void wait_task_inactive(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001108{
1109 unsigned long flags;
Ingo Molnardd41f592007-07-09 18:51:59 +02001110 int running, on_rq;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001111 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001112
Andi Kleen3a5c3592007-10-15 17:00:14 +02001113 for (;;) {
1114 /*
1115 * We do the initial early heuristics without holding
1116 * any task-queue locks at all. We'll only try to get
1117 * the runqueue lock when things look like they will
1118 * work out!
1119 */
1120 rq = task_rq(p);
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001121
Andi Kleen3a5c3592007-10-15 17:00:14 +02001122 /*
1123 * If the task is actively running on another CPU
1124 * still, just relax and busy-wait without holding
1125 * any locks.
1126 *
1127 * NOTE! Since we don't hold any locks, it's not
1128 * even sure that "rq" stays as the right runqueue!
1129 * But we don't care, since "task_running()" will
1130 * return false if the runqueue has changed and p
1131 * is actually now running somewhere else!
1132 */
1133 while (task_running(rq, p))
1134 cpu_relax();
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001135
Andi Kleen3a5c3592007-10-15 17:00:14 +02001136 /*
1137 * Ok, time to look more closely! We need the rq
1138 * lock now, to be *sure*. If we're wrong, we'll
1139 * just go back and repeat.
1140 */
1141 rq = task_rq_lock(p, &flags);
1142 running = task_running(rq, p);
1143 on_rq = p->se.on_rq;
1144 task_rq_unlock(rq, &flags);
Linus Torvaldsfa490cf2007-06-18 09:34:40 -07001145
Andi Kleen3a5c3592007-10-15 17:00:14 +02001146 /*
1147 * Was it really running after all now that we
1148 * checked with the proper locks actually held?
1149 *
1150 * Oops. Go back and try again..
1151 */
1152 if (unlikely(running)) {
1153 cpu_relax();
1154 continue;
1155 }
1156
1157 /*
1158 * It's not enough that it's not actively running,
1159 * it must be off the runqueue _entirely_, and not
1160 * preempted!
1161 *
1162 * So if it wa still runnable (but just not actively
1163 * running right now), it's preempted, and we should
1164 * yield - it could be a while.
1165 */
1166 if (unlikely(on_rq)) {
1167 schedule_timeout_uninterruptible(1);
1168 continue;
1169 }
1170
1171 /*
1172 * Ahh, all good. It wasn't running, and it wasn't
1173 * runnable, which means that it will never become
1174 * running in the future either. We're all done!
1175 */
1176 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001177 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178}
1179
1180/***
1181 * kick_process - kick a running thread to enter/exit the kernel
1182 * @p: the to-be-kicked thread
1183 *
1184 * Cause a process which is running on another CPU to enter
1185 * kernel-mode, without any delay. (to get signals handled.)
1186 *
1187 * NOTE: this function doesnt have to take the runqueue lock,
1188 * because all it wants to ensure is that the remote task enters
1189 * the kernel. If the IPI races and the task has been migrated
1190 * to another CPU then no harm is done and the purpose has been
1191 * achieved as well.
1192 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001193void kick_process(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001194{
1195 int cpu;
1196
1197 preempt_disable();
1198 cpu = task_cpu(p);
1199 if ((cpu != smp_processor_id()) && task_curr(p))
1200 smp_send_reschedule(cpu);
1201 preempt_enable();
1202}
1203
1204/*
Peter Williams2dd73a42006-06-27 02:54:34 -07001205 * Return a low guess at the load of a migration-source cpu weighted
1206 * according to the scheduling class and "nice" value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001207 *
1208 * We want to under-estimate the load of migration sources, to
1209 * balance conservatively.
1210 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02001211static unsigned long source_load(int cpu, int type)
Con Kolivasb9104722005-11-08 21:38:55 -08001212{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001213 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001214 unsigned long total = weighted_cpuload(cpu);
Nick Piggina2000572006-02-10 01:51:02 -08001215
Peter Williams2dd73a42006-06-27 02:54:34 -07001216 if (type == 0)
Ingo Molnardd41f592007-07-09 18:51:59 +02001217 return total;
Peter Williams2dd73a42006-06-27 02:54:34 -07001218
Ingo Molnardd41f592007-07-09 18:51:59 +02001219 return min(rq->cpu_load[type-1], total);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001220}
1221
1222/*
Peter Williams2dd73a42006-06-27 02:54:34 -07001223 * Return a high guess at the load of a migration-target cpu weighted
1224 * according to the scheduling class and "nice" value.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001225 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02001226static unsigned long target_load(int cpu, int type)
Con Kolivasb9104722005-11-08 21:38:55 -08001227{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001228 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001229 unsigned long total = weighted_cpuload(cpu);
Nick Piggina2000572006-02-10 01:51:02 -08001230
Peter Williams2dd73a42006-06-27 02:54:34 -07001231 if (type == 0)
Ingo Molnardd41f592007-07-09 18:51:59 +02001232 return total;
Peter Williams2dd73a42006-06-27 02:54:34 -07001233
Ingo Molnardd41f592007-07-09 18:51:59 +02001234 return max(rq->cpu_load[type-1], total);
Peter Williams2dd73a42006-06-27 02:54:34 -07001235}
1236
1237/*
1238 * Return the average load per task on the cpu's run queue
1239 */
1240static inline unsigned long cpu_avg_load_per_task(int cpu)
1241{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001242 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02001243 unsigned long total = weighted_cpuload(cpu);
Peter Williams2dd73a42006-06-27 02:54:34 -07001244 unsigned long n = rq->nr_running;
1245
Ingo Molnardd41f592007-07-09 18:51:59 +02001246 return n ? total / n : SCHED_LOAD_SCALE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001247}
1248
Nick Piggin147cbb42005-06-25 14:57:19 -07001249/*
1250 * find_idlest_group finds and returns the least busy CPU group within the
1251 * domain.
1252 */
1253static struct sched_group *
1254find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu)
1255{
1256 struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups;
1257 unsigned long min_load = ULONG_MAX, this_load = 0;
1258 int load_idx = sd->forkexec_idx;
1259 int imbalance = 100 + (sd->imbalance_pct-100)/2;
1260
1261 do {
1262 unsigned long load, avg_load;
1263 int local_group;
1264 int i;
1265
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001266 /* Skip over this group if it has no CPUs allowed */
1267 if (!cpus_intersects(group->cpumask, p->cpus_allowed))
Andi Kleen3a5c3592007-10-15 17:00:14 +02001268 continue;
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001269
Nick Piggin147cbb42005-06-25 14:57:19 -07001270 local_group = cpu_isset(this_cpu, group->cpumask);
Nick Piggin147cbb42005-06-25 14:57:19 -07001271
1272 /* Tally up the load of all CPUs in the group */
1273 avg_load = 0;
1274
1275 for_each_cpu_mask(i, group->cpumask) {
1276 /* Bias balancing toward cpus of our domain */
1277 if (local_group)
1278 load = source_load(i, load_idx);
1279 else
1280 load = target_load(i, load_idx);
1281
1282 avg_load += load;
1283 }
1284
1285 /* Adjust by relative CPU power of the group */
Eric Dumazet5517d862007-05-08 00:32:57 -07001286 avg_load = sg_div_cpu_power(group,
1287 avg_load * SCHED_LOAD_SCALE);
Nick Piggin147cbb42005-06-25 14:57:19 -07001288
1289 if (local_group) {
1290 this_load = avg_load;
1291 this = group;
1292 } else if (avg_load < min_load) {
1293 min_load = avg_load;
1294 idlest = group;
1295 }
Andi Kleen3a5c3592007-10-15 17:00:14 +02001296 } while (group = group->next, group != sd->groups);
Nick Piggin147cbb42005-06-25 14:57:19 -07001297
1298 if (!idlest || 100*this_load < imbalance*min_load)
1299 return NULL;
1300 return idlest;
1301}
1302
1303/*
Satoru Takeuchi0feaece2006-10-03 01:14:10 -07001304 * find_idlest_cpu - find the idlest cpu among the cpus in group.
Nick Piggin147cbb42005-06-25 14:57:19 -07001305 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07001306static int
1307find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu)
Nick Piggin147cbb42005-06-25 14:57:19 -07001308{
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001309 cpumask_t tmp;
Nick Piggin147cbb42005-06-25 14:57:19 -07001310 unsigned long load, min_load = ULONG_MAX;
1311 int idlest = -1;
1312 int i;
1313
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001314 /* Traverse only the allowed CPUs */
1315 cpus_and(tmp, group->cpumask, p->cpus_allowed);
1316
1317 for_each_cpu_mask(i, tmp) {
Peter Williams2dd73a42006-06-27 02:54:34 -07001318 load = weighted_cpuload(i);
Nick Piggin147cbb42005-06-25 14:57:19 -07001319
1320 if (load < min_load || (load == min_load && i == this_cpu)) {
1321 min_load = load;
1322 idlest = i;
1323 }
1324 }
1325
1326 return idlest;
1327}
1328
Nick Piggin476d1392005-06-25 14:57:29 -07001329/*
1330 * sched_balance_self: balance the current task (running on cpu) in domains
1331 * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
1332 * SD_BALANCE_EXEC.
1333 *
1334 * Balance, ie. select the least loaded group.
1335 *
1336 * Returns the target CPU number, or the same CPU if no balancing is needed.
1337 *
1338 * preempt must be disabled.
1339 */
1340static int sched_balance_self(int cpu, int flag)
1341{
1342 struct task_struct *t = current;
1343 struct sched_domain *tmp, *sd = NULL;
Nick Piggin147cbb42005-06-25 14:57:19 -07001344
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07001345 for_each_domain(cpu, tmp) {
Ingo Molnar9761eea2007-07-09 18:52:00 +02001346 /*
1347 * If power savings logic is enabled for a domain, stop there.
1348 */
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07001349 if (tmp->flags & SD_POWERSAVINGS_BALANCE)
1350 break;
Nick Piggin476d1392005-06-25 14:57:29 -07001351 if (tmp->flags & flag)
1352 sd = tmp;
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07001353 }
Nick Piggin476d1392005-06-25 14:57:29 -07001354
1355 while (sd) {
1356 cpumask_t span;
1357 struct sched_group *group;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07001358 int new_cpu, weight;
1359
1360 if (!(sd->flags & flag)) {
1361 sd = sd->child;
1362 continue;
1363 }
Nick Piggin476d1392005-06-25 14:57:29 -07001364
1365 span = sd->span;
1366 group = find_idlest_group(sd, t, cpu);
Siddha, Suresh B1a848872006-10-03 01:14:08 -07001367 if (!group) {
1368 sd = sd->child;
1369 continue;
1370 }
Nick Piggin476d1392005-06-25 14:57:29 -07001371
M.Baris Demirayda5a5522005-09-10 00:26:09 -07001372 new_cpu = find_idlest_cpu(group, t, cpu);
Siddha, Suresh B1a848872006-10-03 01:14:08 -07001373 if (new_cpu == -1 || new_cpu == cpu) {
1374 /* Now try balancing at a lower domain level of cpu */
1375 sd = sd->child;
1376 continue;
1377 }
Nick Piggin476d1392005-06-25 14:57:29 -07001378
Siddha, Suresh B1a848872006-10-03 01:14:08 -07001379 /* Now try balancing at a lower domain level of new_cpu */
Nick Piggin476d1392005-06-25 14:57:29 -07001380 cpu = new_cpu;
Nick Piggin476d1392005-06-25 14:57:29 -07001381 sd = NULL;
1382 weight = cpus_weight(span);
1383 for_each_domain(cpu, tmp) {
1384 if (weight <= cpus_weight(tmp->span))
1385 break;
1386 if (tmp->flags & flag)
1387 sd = tmp;
1388 }
1389 /* while loop will break here if sd == NULL */
1390 }
1391
1392 return cpu;
1393}
1394
1395#endif /* CONFIG_SMP */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001396
1397/*
1398 * wake_idle() will wake a task on an idle cpu if task->cpu is
1399 * not idle and an idle cpu is available. The span of cpus to
1400 * search starts with cpus closest then further out as needed,
1401 * so we always favor a closer, idle cpu.
1402 *
1403 * Returns the CPU we should wake onto.
1404 */
1405#if defined(ARCH_HAS_SCHED_WAKE_IDLE)
Ingo Molnar36c8b582006-07-03 00:25:41 -07001406static int wake_idle(int cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001407{
1408 cpumask_t tmp;
1409 struct sched_domain *sd;
1410 int i;
1411
Siddha, Suresh B49531982007-05-08 00:33:01 -07001412 /*
1413 * If it is idle, then it is the best cpu to run this task.
1414 *
1415 * This cpu is also the best, if it has more than one task already.
1416 * Siblings must be also busy(in most cases) as they didn't already
1417 * pickup the extra load from this cpu and hence we need not check
1418 * sibling runqueue info. This will avoid the checks and cache miss
1419 * penalities associated with that.
1420 */
1421 if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001422 return cpu;
1423
1424 for_each_domain(cpu, sd) {
1425 if (sd->flags & SD_WAKE_IDLE) {
Nick Piggine0f364f2005-06-25 14:57:06 -07001426 cpus_and(tmp, sd->span, p->cpus_allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001427 for_each_cpu_mask(i, tmp) {
Ingo Molnarcc367732007-10-15 17:00:18 +02001428 if (idle_cpu(i)) {
1429 if (i != task_cpu(p)) {
1430 schedstat_inc(p,
1431 se.nr_wakeups_idle);
1432 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001433 return i;
Ingo Molnarcc367732007-10-15 17:00:18 +02001434 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001435 }
Ingo Molnar9761eea2007-07-09 18:52:00 +02001436 } else {
Nick Piggine0f364f2005-06-25 14:57:06 -07001437 break;
Ingo Molnar9761eea2007-07-09 18:52:00 +02001438 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001439 }
1440 return cpu;
1441}
1442#else
Ingo Molnar36c8b582006-07-03 00:25:41 -07001443static inline int wake_idle(int cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001444{
1445 return cpu;
1446}
1447#endif
1448
1449/***
1450 * try_to_wake_up - wake up a thread
1451 * @p: the to-be-woken-up thread
1452 * @state: the mask of task states that can be woken
1453 * @sync: do a synchronous wakeup?
1454 *
1455 * Put it on the run-queue if it's not already there. The "current"
1456 * thread is always on the run-queue (except when the actual
1457 * re-schedule is in progress), and as such you're allowed to do
1458 * the simpler "current->state = TASK_RUNNING" to mark yourself
1459 * runnable without the overhead of this.
1460 *
1461 * returns failure only if the task is already active.
1462 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001463static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001464{
Ingo Molnarcc367732007-10-15 17:00:18 +02001465 int cpu, orig_cpu, this_cpu, success = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001466 unsigned long flags;
1467 long old_state;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001468 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001469#ifdef CONFIG_SMP
Nick Piggin78979862005-06-25 14:57:13 -07001470 struct sched_domain *sd, *this_sd = NULL;
Ingo Molnar70b97a72006-07-03 00:25:42 -07001471 unsigned long load, this_load;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001472 int new_cpu;
1473#endif
1474
1475 rq = task_rq_lock(p, &flags);
1476 old_state = p->state;
1477 if (!(old_state & state))
1478 goto out;
1479
Ingo Molnardd41f592007-07-09 18:51:59 +02001480 if (p->se.on_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001481 goto out_running;
1482
1483 cpu = task_cpu(p);
Ingo Molnarcc367732007-10-15 17:00:18 +02001484 orig_cpu = cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 this_cpu = smp_processor_id();
1486
1487#ifdef CONFIG_SMP
1488 if (unlikely(task_running(rq, p)))
1489 goto out_activate;
1490
Nick Piggin78979862005-06-25 14:57:13 -07001491 new_cpu = cpu;
1492
Ingo Molnar2d723762007-10-15 17:00:12 +02001493 schedstat_inc(rq, ttwu_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001494 if (cpu == this_cpu) {
1495 schedstat_inc(rq, ttwu_local);
Nick Piggin78979862005-06-25 14:57:13 -07001496 goto out_set_cpu;
1497 }
1498
1499 for_each_domain(this_cpu, sd) {
1500 if (cpu_isset(cpu, sd->span)) {
1501 schedstat_inc(sd, ttwu_wake_remote);
1502 this_sd = sd;
1503 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001504 }
1505 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001506
Nick Piggin78979862005-06-25 14:57:13 -07001507 if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001508 goto out_set_cpu;
1509
Linus Torvalds1da177e2005-04-16 15:20:36 -07001510 /*
Nick Piggin78979862005-06-25 14:57:13 -07001511 * Check for affine wakeup and passive balancing possibilities.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001512 */
Nick Piggin78979862005-06-25 14:57:13 -07001513 if (this_sd) {
1514 int idx = this_sd->wake_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001515 unsigned int imbalance;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001516
Nick Piggina3f21bc2005-06-25 14:57:15 -07001517 imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
1518
Nick Piggin78979862005-06-25 14:57:13 -07001519 load = source_load(cpu, idx);
1520 this_load = target_load(this_cpu, idx);
1521
Nick Piggin78979862005-06-25 14:57:13 -07001522 new_cpu = this_cpu; /* Wake to this CPU if we can */
1523
Nick Piggina3f21bc2005-06-25 14:57:15 -07001524 if (this_sd->flags & SD_WAKE_AFFINE) {
1525 unsigned long tl = this_load;
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08001526 unsigned long tl_per_task;
1527
Ingo Molnar71e20f12007-10-15 17:00:19 +02001528 /*
1529 * Attract cache-cold tasks on sync wakeups:
1530 */
1531 if (sync && !task_hot(p, rq->clock, this_sd))
1532 goto out_set_cpu;
1533
Ingo Molnarcc367732007-10-15 17:00:18 +02001534 schedstat_inc(p, se.nr_wakeups_affine_attempts);
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08001535 tl_per_task = cpu_avg_load_per_task(this_cpu);
Peter Williams2dd73a42006-06-27 02:54:34 -07001536
Linus Torvalds1da177e2005-04-16 15:20:36 -07001537 /*
Nick Piggina3f21bc2005-06-25 14:57:15 -07001538 * If sync wakeup then subtract the (maximum possible)
1539 * effect of the currently running task from the load
1540 * of the current CPU:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001541 */
Nick Piggina3f21bc2005-06-25 14:57:15 -07001542 if (sync)
Ingo Molnardd41f592007-07-09 18:51:59 +02001543 tl -= current->se.load.weight;
Nick Piggina3f21bc2005-06-25 14:57:15 -07001544
1545 if ((tl <= load &&
Peter Williams2dd73a42006-06-27 02:54:34 -07001546 tl + target_load(cpu, idx) <= tl_per_task) ||
Ingo Molnardd41f592007-07-09 18:51:59 +02001547 100*(tl + p->se.load.weight) <= imbalance*load) {
Nick Piggina3f21bc2005-06-25 14:57:15 -07001548 /*
1549 * This domain has SD_WAKE_AFFINE and
1550 * p is cache cold in this domain, and
1551 * there is no bad imbalance.
1552 */
1553 schedstat_inc(this_sd, ttwu_move_affine);
Ingo Molnarcc367732007-10-15 17:00:18 +02001554 schedstat_inc(p, se.nr_wakeups_affine);
Nick Piggina3f21bc2005-06-25 14:57:15 -07001555 goto out_set_cpu;
1556 }
1557 }
1558
1559 /*
1560 * Start passive balancing when half the imbalance_pct
1561 * limit is reached.
1562 */
1563 if (this_sd->flags & SD_WAKE_BALANCE) {
1564 if (imbalance*this_load <= 100*load) {
1565 schedstat_inc(this_sd, ttwu_move_balance);
Ingo Molnarcc367732007-10-15 17:00:18 +02001566 schedstat_inc(p, se.nr_wakeups_passive);
Nick Piggina3f21bc2005-06-25 14:57:15 -07001567 goto out_set_cpu;
1568 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001569 }
1570 }
1571
1572 new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
1573out_set_cpu:
1574 new_cpu = wake_idle(new_cpu, p);
1575 if (new_cpu != cpu) {
1576 set_task_cpu(p, new_cpu);
1577 task_rq_unlock(rq, &flags);
1578 /* might preempt at this point */
1579 rq = task_rq_lock(p, &flags);
1580 old_state = p->state;
1581 if (!(old_state & state))
1582 goto out;
Ingo Molnardd41f592007-07-09 18:51:59 +02001583 if (p->se.on_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001584 goto out_running;
1585
1586 this_cpu = smp_processor_id();
1587 cpu = task_cpu(p);
1588 }
1589
1590out_activate:
1591#endif /* CONFIG_SMP */
Ingo Molnarcc367732007-10-15 17:00:18 +02001592 schedstat_inc(p, se.nr_wakeups);
1593 if (sync)
1594 schedstat_inc(p, se.nr_wakeups_sync);
1595 if (orig_cpu != cpu)
1596 schedstat_inc(p, se.nr_wakeups_migrate);
1597 if (cpu == this_cpu)
1598 schedstat_inc(p, se.nr_wakeups_local);
1599 else
1600 schedstat_inc(p, se.nr_wakeups_remote);
Ingo Molnar2daa3572007-08-09 11:16:51 +02001601 update_rq_clock(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02001602 activate_task(rq, p, 1);
Ingo Molnar9c63d9c2007-10-15 17:00:20 +02001603 check_preempt_curr(rq, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001604 success = 1;
1605
1606out_running:
1607 p->state = TASK_RUNNING;
1608out:
1609 task_rq_unlock(rq, &flags);
1610
1611 return success;
1612}
1613
Ingo Molnar36c8b582006-07-03 00:25:41 -07001614int fastcall wake_up_process(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001615{
1616 return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED |
1617 TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0);
1618}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001619EXPORT_SYMBOL(wake_up_process);
1620
Ingo Molnar36c8b582006-07-03 00:25:41 -07001621int fastcall wake_up_state(struct task_struct *p, unsigned int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001622{
1623 return try_to_wake_up(p, state, 0);
1624}
1625
Linus Torvalds1da177e2005-04-16 15:20:36 -07001626/*
1627 * Perform scheduler related setup for a newly forked process p.
1628 * p is forked by current.
Ingo Molnardd41f592007-07-09 18:51:59 +02001629 *
1630 * __sched_fork() is basic setup used by init_idle() too:
Linus Torvalds1da177e2005-04-16 15:20:36 -07001631 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001632static void __sched_fork(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001633{
Ingo Molnardd41f592007-07-09 18:51:59 +02001634 p->se.exec_start = 0;
1635 p->se.sum_exec_runtime = 0;
Ingo Molnarf6cf8912007-08-28 12:53:24 +02001636 p->se.prev_sum_exec_runtime = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001637
1638#ifdef CONFIG_SCHEDSTATS
1639 p->se.wait_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02001640 p->se.sum_sleep_runtime = 0;
1641 p->se.sleep_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02001642 p->se.block_start = 0;
1643 p->se.sleep_max = 0;
1644 p->se.block_max = 0;
1645 p->se.exec_max = 0;
Ingo Molnareba1ed42007-10-15 17:00:02 +02001646 p->se.slice_max = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02001647 p->se.wait_max = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02001648#endif
Nick Piggin476d1392005-06-25 14:57:29 -07001649
Ingo Molnardd41f592007-07-09 18:51:59 +02001650 INIT_LIST_HEAD(&p->run_list);
1651 p->se.on_rq = 0;
Nick Piggin476d1392005-06-25 14:57:29 -07001652
Avi Kivitye107be32007-07-26 13:40:43 +02001653#ifdef CONFIG_PREEMPT_NOTIFIERS
1654 INIT_HLIST_HEAD(&p->preempt_notifiers);
1655#endif
1656
Linus Torvalds1da177e2005-04-16 15:20:36 -07001657 /*
1658 * We mark the process as running here, but have not actually
1659 * inserted it onto the runqueue yet. This guarantees that
1660 * nobody will actually run it, and a signal or other external
1661 * event cannot wake it up and insert it on the runqueue either.
1662 */
1663 p->state = TASK_RUNNING;
Ingo Molnardd41f592007-07-09 18:51:59 +02001664}
1665
1666/*
1667 * fork()/clone()-time setup:
1668 */
1669void sched_fork(struct task_struct *p, int clone_flags)
1670{
1671 int cpu = get_cpu();
1672
1673 __sched_fork(p);
1674
1675#ifdef CONFIG_SMP
1676 cpu = sched_balance_self(cpu, SD_BALANCE_FORK);
1677#endif
Ingo Molnar02e4bac2007-10-15 17:00:11 +02001678 set_task_cpu(p, cpu);
Ingo Molnarb29739f2006-06-27 02:54:51 -07001679
1680 /*
1681 * Make sure we do not leak PI boosting priority to the child:
1682 */
1683 p->prio = current->normal_prio;
Hiroshi Shimamoto2ddbf952007-10-15 17:00:11 +02001684 if (!rt_prio(p->prio))
1685 p->sched_class = &fair_sched_class;
Ingo Molnarb29739f2006-06-27 02:54:51 -07001686
Chandra Seetharaman52f17b62006-07-14 00:24:38 -07001687#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
Ingo Molnardd41f592007-07-09 18:51:59 +02001688 if (likely(sched_info_on()))
Chandra Seetharaman52f17b62006-07-14 00:24:38 -07001689 memset(&p->sched_info, 0, sizeof(p->sched_info));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001690#endif
Chen, Kenneth Wd6077cb2006-02-14 13:53:10 -08001691#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
Nick Piggin4866cde2005-06-25 14:57:23 -07001692 p->oncpu = 0;
1693#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694#ifdef CONFIG_PREEMPT
Nick Piggin4866cde2005-06-25 14:57:23 -07001695 /* Want to start with kernel preemption disabled. */
Al Viroa1261f52005-11-13 16:06:55 -08001696 task_thread_info(p)->preempt_count = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001697#endif
Nick Piggin476d1392005-06-25 14:57:29 -07001698 put_cpu();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001699}
1700
1701/*
1702 * wake_up_new_task - wake up a newly created task for the first time.
1703 *
1704 * This function will do some initial scheduler statistics housekeeping
1705 * that must be done for every newly created context, then puts the task
1706 * on the runqueue and wakes it.
1707 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001708void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001709{
1710 unsigned long flags;
Ingo Molnardd41f592007-07-09 18:51:59 +02001711 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001712
1713 rq = task_rq_lock(p, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001714 BUG_ON(p->state != TASK_RUNNING);
Ingo Molnara8e504d2007-08-09 11:16:47 +02001715 update_rq_clock(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001716
1717 p->prio = effective_prio(p);
1718
Srivatsa Vaddagirib9dca1e2007-10-17 16:55:11 +02001719 if (!p->sched_class->task_new || !current->se.on_rq) {
Ingo Molnardd41f592007-07-09 18:51:59 +02001720 activate_task(rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001721 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001722 /*
Ingo Molnardd41f592007-07-09 18:51:59 +02001723 * Let the scheduling class do new task startup
1724 * management (if any):
Linus Torvalds1da177e2005-04-16 15:20:36 -07001725 */
Ingo Molnaree0827d2007-08-09 11:16:49 +02001726 p->sched_class->task_new(rq, p);
Ingo Molnare5fa2232007-08-09 11:16:49 +02001727 inc_nr_running(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001728 }
Ingo Molnardd41f592007-07-09 18:51:59 +02001729 check_preempt_curr(rq, p);
1730 task_rq_unlock(rq, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001731}
1732
Avi Kivitye107be32007-07-26 13:40:43 +02001733#ifdef CONFIG_PREEMPT_NOTIFIERS
1734
1735/**
Randy Dunlap421cee22007-07-31 00:37:50 -07001736 * preempt_notifier_register - tell me when current is being being preempted & rescheduled
1737 * @notifier: notifier struct to register
Avi Kivitye107be32007-07-26 13:40:43 +02001738 */
1739void preempt_notifier_register(struct preempt_notifier *notifier)
1740{
1741 hlist_add_head(&notifier->link, &current->preempt_notifiers);
1742}
1743EXPORT_SYMBOL_GPL(preempt_notifier_register);
1744
1745/**
1746 * preempt_notifier_unregister - no longer interested in preemption notifications
Randy Dunlap421cee22007-07-31 00:37:50 -07001747 * @notifier: notifier struct to unregister
Avi Kivitye107be32007-07-26 13:40:43 +02001748 *
1749 * This is safe to call from within a preemption notifier.
1750 */
1751void preempt_notifier_unregister(struct preempt_notifier *notifier)
1752{
1753 hlist_del(&notifier->link);
1754}
1755EXPORT_SYMBOL_GPL(preempt_notifier_unregister);
1756
1757static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1758{
1759 struct preempt_notifier *notifier;
1760 struct hlist_node *node;
1761
1762 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1763 notifier->ops->sched_in(notifier, raw_smp_processor_id());
1764}
1765
1766static void
1767fire_sched_out_preempt_notifiers(struct task_struct *curr,
1768 struct task_struct *next)
1769{
1770 struct preempt_notifier *notifier;
1771 struct hlist_node *node;
1772
1773 hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link)
1774 notifier->ops->sched_out(notifier, next);
1775}
1776
1777#else
1778
1779static void fire_sched_in_preempt_notifiers(struct task_struct *curr)
1780{
1781}
1782
1783static void
1784fire_sched_out_preempt_notifiers(struct task_struct *curr,
1785 struct task_struct *next)
1786{
1787}
1788
1789#endif
1790
Linus Torvalds1da177e2005-04-16 15:20:36 -07001791/**
Nick Piggin4866cde2005-06-25 14:57:23 -07001792 * prepare_task_switch - prepare to switch tasks
1793 * @rq: the runqueue preparing to switch
Randy Dunlap421cee22007-07-31 00:37:50 -07001794 * @prev: the current task that is being switched out
Nick Piggin4866cde2005-06-25 14:57:23 -07001795 * @next: the task we are going to switch to.
1796 *
1797 * This is called with the rq lock held and interrupts off. It must
1798 * be paired with a subsequent finish_task_switch after the context
1799 * switch.
1800 *
1801 * prepare_task_switch sets up locking and calls architecture specific
1802 * hooks.
1803 */
Avi Kivitye107be32007-07-26 13:40:43 +02001804static inline void
1805prepare_task_switch(struct rq *rq, struct task_struct *prev,
1806 struct task_struct *next)
Nick Piggin4866cde2005-06-25 14:57:23 -07001807{
Avi Kivitye107be32007-07-26 13:40:43 +02001808 fire_sched_out_preempt_notifiers(prev, next);
Nick Piggin4866cde2005-06-25 14:57:23 -07001809 prepare_lock_switch(rq, next);
1810 prepare_arch_switch(next);
1811}
1812
1813/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07001814 * finish_task_switch - clean up after a task-switch
Jeff Garzik344baba2005-09-07 01:15:17 -04001815 * @rq: runqueue associated with task-switch
Linus Torvalds1da177e2005-04-16 15:20:36 -07001816 * @prev: the thread we just switched away from.
1817 *
Nick Piggin4866cde2005-06-25 14:57:23 -07001818 * finish_task_switch must be called after the context switch, paired
1819 * with a prepare_task_switch call before the context switch.
1820 * finish_task_switch will reconcile locking set up by prepare_task_switch,
1821 * and do any other architecture-specific cleanup actions.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001822 *
1823 * Note that we may have delayed dropping an mm in context_switch(). If
1824 * so, we finish that here outside of the runqueue lock. (Doing it
1825 * with the lock held can cause deadlocks; see schedule() for
1826 * details.)
1827 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02001828static void finish_task_switch(struct rq *rq, struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 __releases(rq->lock)
1830{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001831 struct mm_struct *mm = rq->prev_mm;
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001832 long prev_state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001833
1834 rq->prev_mm = NULL;
1835
1836 /*
1837 * A task struct has one reference for the use as "current".
Oleg Nesterovc394cc92006-09-29 02:01:11 -07001838 * If a task dies, then it sets TASK_DEAD in tsk->state and calls
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001839 * schedule one last time. The schedule call will never return, and
1840 * the scheduled task must drop that reference.
Oleg Nesterovc394cc92006-09-29 02:01:11 -07001841 * The test for TASK_DEAD must occur while the runqueue locks are
Linus Torvalds1da177e2005-04-16 15:20:36 -07001842 * still held, otherwise prev could be scheduled on another cpu, die
1843 * there before we look at prev->state, and then the reference would
1844 * be dropped twice.
1845 * Manfred Spraul <manfred@colorfullife.com>
1846 */
Oleg Nesterov55a101f2006-09-29 02:01:10 -07001847 prev_state = prev->state;
Nick Piggin4866cde2005-06-25 14:57:23 -07001848 finish_arch_switch(prev);
1849 finish_lock_switch(rq, prev);
Avi Kivitye107be32007-07-26 13:40:43 +02001850 fire_sched_in_preempt_notifiers(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001851 if (mm)
1852 mmdrop(mm);
Oleg Nesterovc394cc92006-09-29 02:01:11 -07001853 if (unlikely(prev_state == TASK_DEAD)) {
bibo maoc6fd91f2006-03-26 01:38:20 -08001854 /*
1855 * Remove function-return probe instances associated with this
1856 * task and put them back on the free list.
Ingo Molnar9761eea2007-07-09 18:52:00 +02001857 */
bibo maoc6fd91f2006-03-26 01:38:20 -08001858 kprobe_flush_task(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001859 put_task_struct(prev);
bibo maoc6fd91f2006-03-26 01:38:20 -08001860 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001861}
1862
1863/**
1864 * schedule_tail - first thing a freshly forked thread must call.
1865 * @prev: the thread we just switched away from.
1866 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07001867asmlinkage void schedule_tail(struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001868 __releases(rq->lock)
1869{
Ingo Molnar70b97a72006-07-03 00:25:42 -07001870 struct rq *rq = this_rq();
1871
Nick Piggin4866cde2005-06-25 14:57:23 -07001872 finish_task_switch(rq, prev);
1873#ifdef __ARCH_WANT_UNLOCKED_CTXSW
1874 /* In this case, finish_task_switch does not reenable preemption */
1875 preempt_enable();
1876#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877 if (current->set_child_tid)
1878 put_user(current->pid, current->set_child_tid);
1879}
1880
1881/*
1882 * context_switch - switch to the new MM and the new
1883 * thread's register state.
1884 */
Ingo Molnardd41f592007-07-09 18:51:59 +02001885static inline void
Ingo Molnar70b97a72006-07-03 00:25:42 -07001886context_switch(struct rq *rq, struct task_struct *prev,
Ingo Molnar36c8b582006-07-03 00:25:41 -07001887 struct task_struct *next)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888{
Ingo Molnardd41f592007-07-09 18:51:59 +02001889 struct mm_struct *mm, *oldmm;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001890
Avi Kivitye107be32007-07-26 13:40:43 +02001891 prepare_task_switch(rq, prev, next);
Ingo Molnardd41f592007-07-09 18:51:59 +02001892 mm = next->mm;
1893 oldmm = prev->active_mm;
Zachary Amsden9226d122007-02-13 13:26:21 +01001894 /*
1895 * For paravirt, this is coupled with an exit in switch_to to
1896 * combine the page table reload and the switch backend into
1897 * one hypercall.
1898 */
1899 arch_enter_lazy_cpu_mode();
1900
Ingo Molnardd41f592007-07-09 18:51:59 +02001901 if (unlikely(!mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001902 next->active_mm = oldmm;
1903 atomic_inc(&oldmm->mm_count);
1904 enter_lazy_tlb(oldmm, next);
1905 } else
1906 switch_mm(oldmm, mm, next);
1907
Ingo Molnardd41f592007-07-09 18:51:59 +02001908 if (unlikely(!prev->mm)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001909 prev->active_mm = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001910 rq->prev_mm = oldmm;
1911 }
Ingo Molnar3a5f5e42006-07-14 00:24:27 -07001912 /*
1913 * Since the runqueue lock will be released by the next
1914 * task (which is an invalid locking op but in the case
1915 * of the scheduler it's an obvious special-case), so we
1916 * do an early lockdep release here:
1917 */
1918#ifndef __ARCH_WANT_UNLOCKED_CTXSW
Ingo Molnar8a25d5d2006-07-03 00:24:54 -07001919 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
Ingo Molnar3a5f5e42006-07-14 00:24:27 -07001920#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921
1922 /* Here we just switch the register state and the stack. */
1923 switch_to(prev, next, prev);
1924
Ingo Molnardd41f592007-07-09 18:51:59 +02001925 barrier();
1926 /*
1927 * this_rq must be evaluated again because prev may have moved
1928 * CPUs since it called schedule(), thus the 'rq' on its stack
1929 * frame will be invalid.
1930 */
1931 finish_task_switch(this_rq(), prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001932}
1933
1934/*
1935 * nr_running, nr_uninterruptible and nr_context_switches:
1936 *
1937 * externally visible scheduler statistics: current number of runnable
1938 * threads, current number of uninterruptible-sleeping threads, total
1939 * number of context switches performed since bootup.
1940 */
1941unsigned long nr_running(void)
1942{
1943 unsigned long i, sum = 0;
1944
1945 for_each_online_cpu(i)
1946 sum += cpu_rq(i)->nr_running;
1947
1948 return sum;
1949}
1950
1951unsigned long nr_uninterruptible(void)
1952{
1953 unsigned long i, sum = 0;
1954
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08001955 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001956 sum += cpu_rq(i)->nr_uninterruptible;
1957
1958 /*
1959 * Since we read the counters lockless, it might be slightly
1960 * inaccurate. Do not allow it to go below zero though:
1961 */
1962 if (unlikely((long)sum < 0))
1963 sum = 0;
1964
1965 return sum;
1966}
1967
1968unsigned long long nr_context_switches(void)
1969{
Steven Rostedtcc94abf2006-06-27 02:54:31 -07001970 int i;
1971 unsigned long long sum = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08001973 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 sum += cpu_rq(i)->nr_switches;
1975
1976 return sum;
1977}
1978
1979unsigned long nr_iowait(void)
1980{
1981 unsigned long i, sum = 0;
1982
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08001983 for_each_possible_cpu(i)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 sum += atomic_read(&cpu_rq(i)->nr_iowait);
1985
1986 return sum;
1987}
1988
Jack Steinerdb1b1fe2006-03-31 02:31:21 -08001989unsigned long nr_active(void)
1990{
1991 unsigned long i, running = 0, uninterruptible = 0;
1992
1993 for_each_online_cpu(i) {
1994 running += cpu_rq(i)->nr_running;
1995 uninterruptible += cpu_rq(i)->nr_uninterruptible;
1996 }
1997
1998 if (unlikely((long)uninterruptible < 0))
1999 uninterruptible = 0;
2000
2001 return running + uninterruptible;
2002}
2003
Linus Torvalds1da177e2005-04-16 15:20:36 -07002004/*
Ingo Molnardd41f592007-07-09 18:51:59 +02002005 * Update rq->cpu_load[] statistics. This function is usually called every
2006 * scheduler tick (TICK_NSEC).
Ingo Molnar48f24c42006-07-03 00:25:40 -07002007 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002008static void update_cpu_load(struct rq *this_rq)
Ingo Molnar48f24c42006-07-03 00:25:40 -07002009{
Dmitry Adamushko495eca42007-10-15 17:00:06 +02002010 unsigned long this_load = this_rq->load.weight;
Ingo Molnardd41f592007-07-09 18:51:59 +02002011 int i, scale;
2012
2013 this_rq->nr_load_updates++;
Ingo Molnardd41f592007-07-09 18:51:59 +02002014
2015 /* Update our load: */
2016 for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) {
2017 unsigned long old_load, new_load;
2018
2019 /* scale is effectively 1 << i now, and >> i divides by scale */
2020
2021 old_load = this_rq->cpu_load[i];
2022 new_load = this_load;
Ingo Molnara25707f2007-10-15 17:00:03 +02002023 /*
2024 * Round up the averaging division if load is increasing. This
2025 * prevents us from getting stuck on 9 if the load is 10, for
2026 * example.
2027 */
2028 if (new_load > old_load)
2029 new_load += scale-1;
Ingo Molnardd41f592007-07-09 18:51:59 +02002030 this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i;
2031 }
Ingo Molnar48f24c42006-07-03 00:25:40 -07002032}
2033
Ingo Molnardd41f592007-07-09 18:51:59 +02002034#ifdef CONFIG_SMP
2035
Ingo Molnar48f24c42006-07-03 00:25:40 -07002036/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002037 * double_rq_lock - safely lock two runqueues
2038 *
2039 * Note this does not disable interrupts like task_rq_lock,
2040 * you need to do so manually before calling.
2041 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002042static void double_rq_lock(struct rq *rq1, struct rq *rq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002043 __acquires(rq1->lock)
2044 __acquires(rq2->lock)
2045{
Kirill Korotaev054b9102006-12-10 02:20:11 -08002046 BUG_ON(!irqs_disabled());
Linus Torvalds1da177e2005-04-16 15:20:36 -07002047 if (rq1 == rq2) {
2048 spin_lock(&rq1->lock);
2049 __acquire(rq2->lock); /* Fake it out ;) */
2050 } else {
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002051 if (rq1 < rq2) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002052 spin_lock(&rq1->lock);
2053 spin_lock(&rq2->lock);
2054 } else {
2055 spin_lock(&rq2->lock);
2056 spin_lock(&rq1->lock);
2057 }
2058 }
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02002059 update_rq_clock(rq1);
2060 update_rq_clock(rq2);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002061}
2062
2063/*
2064 * double_rq_unlock - safely unlock two runqueues
2065 *
2066 * Note this does not restore interrupts like task_rq_unlock,
2067 * you need to do so manually after calling.
2068 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002069static void double_rq_unlock(struct rq *rq1, struct rq *rq2)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002070 __releases(rq1->lock)
2071 __releases(rq2->lock)
2072{
2073 spin_unlock(&rq1->lock);
2074 if (rq1 != rq2)
2075 spin_unlock(&rq2->lock);
2076 else
2077 __release(rq2->lock);
2078}
2079
2080/*
2081 * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
2082 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002083static void double_lock_balance(struct rq *this_rq, struct rq *busiest)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002084 __releases(this_rq->lock)
2085 __acquires(busiest->lock)
2086 __acquires(this_rq->lock)
2087{
Kirill Korotaev054b9102006-12-10 02:20:11 -08002088 if (unlikely(!irqs_disabled())) {
2089 /* printk() doesn't work good under rq->lock */
2090 spin_unlock(&this_rq->lock);
2091 BUG_ON(1);
2092 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002093 if (unlikely(!spin_trylock(&busiest->lock))) {
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002094 if (busiest < this_rq) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002095 spin_unlock(&this_rq->lock);
2096 spin_lock(&busiest->lock);
2097 spin_lock(&this_rq->lock);
2098 } else
2099 spin_lock(&busiest->lock);
2100 }
2101}
2102
2103/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002104 * If dest_cpu is allowed for this process, migrate the task to it.
2105 * This is accomplished by forcing the cpu_allowed mask to only
2106 * allow dest_cpu, which will force the cpu onto dest_cpu. Then
2107 * the cpu_allowed mask is restored.
2108 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07002109static void sched_migrate_task(struct task_struct *p, int dest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002110{
Ingo Molnar70b97a72006-07-03 00:25:42 -07002111 struct migration_req req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002112 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002113 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002114
2115 rq = task_rq_lock(p, &flags);
2116 if (!cpu_isset(dest_cpu, p->cpus_allowed)
2117 || unlikely(cpu_is_offline(dest_cpu)))
2118 goto out;
2119
2120 /* force the process onto the specified CPU */
2121 if (migrate_task(p, dest_cpu, &req)) {
2122 /* Need to wait for migration thread (might exit: take ref). */
2123 struct task_struct *mt = rq->migration_thread;
Ingo Molnar36c8b582006-07-03 00:25:41 -07002124
Linus Torvalds1da177e2005-04-16 15:20:36 -07002125 get_task_struct(mt);
2126 task_rq_unlock(rq, &flags);
2127 wake_up_process(mt);
2128 put_task_struct(mt);
2129 wait_for_completion(&req.done);
Ingo Molnar36c8b582006-07-03 00:25:41 -07002130
Linus Torvalds1da177e2005-04-16 15:20:36 -07002131 return;
2132 }
2133out:
2134 task_rq_unlock(rq, &flags);
2135}
2136
2137/*
Nick Piggin476d1392005-06-25 14:57:29 -07002138 * sched_exec - execve() is a valuable balancing opportunity, because at
2139 * this point the task has the smallest effective memory and cache footprint.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002140 */
2141void sched_exec(void)
2142{
Linus Torvalds1da177e2005-04-16 15:20:36 -07002143 int new_cpu, this_cpu = get_cpu();
Nick Piggin476d1392005-06-25 14:57:29 -07002144 new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002145 put_cpu();
Nick Piggin476d1392005-06-25 14:57:29 -07002146 if (new_cpu != this_cpu)
2147 sched_migrate_task(current, new_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002148}
2149
2150/*
2151 * pull_task - move a task from a remote runqueue to the local runqueue.
2152 * Both runqueues must be locked.
2153 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002154static void pull_task(struct rq *src_rq, struct task_struct *p,
2155 struct rq *this_rq, int this_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002156{
Ingo Molnar2e1cb742007-08-09 11:16:49 +02002157 deactivate_task(src_rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002158 set_task_cpu(p, this_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02002159 activate_task(this_rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002160 /*
2161 * Note that idle threads have a prio of MAX_PRIO, for this test
2162 * to be always true for them.
2163 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002164 check_preempt_curr(this_rq, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002165}
2166
2167/*
2168 * can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
2169 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08002170static
Ingo Molnar70b97a72006-07-03 00:25:42 -07002171int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002172 struct sched_domain *sd, enum cpu_idle_type idle,
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07002173 int *all_pinned)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002174{
2175 /*
2176 * We do not migrate tasks that are:
2177 * 1) running (obviously), or
2178 * 2) cannot be migrated to this CPU due to cpus_allowed, or
2179 * 3) are cache-hot on their current CPU.
2180 */
Ingo Molnarcc367732007-10-15 17:00:18 +02002181 if (!cpu_isset(this_cpu, p->cpus_allowed)) {
2182 schedstat_inc(p, se.nr_failed_migrations_affine);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002183 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002184 }
Nick Piggin81026792005-06-25 14:57:07 -07002185 *all_pinned = 0;
2186
Ingo Molnarcc367732007-10-15 17:00:18 +02002187 if (task_running(rq, p)) {
2188 schedstat_inc(p, se.nr_failed_migrations_running);
Nick Piggin81026792005-06-25 14:57:07 -07002189 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002190 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002191
Ingo Molnarda84d962007-10-15 17:00:18 +02002192 /*
2193 * Aggressive migration if:
2194 * 1) task is cache cold, or
2195 * 2) too many balance attempts have failed.
2196 */
2197
Ingo Molnar6bc16652007-10-15 17:00:18 +02002198 if (!task_hot(p, rq->clock, sd) ||
2199 sd->nr_balance_failed > sd->cache_nice_tries) {
Ingo Molnarda84d962007-10-15 17:00:18 +02002200#ifdef CONFIG_SCHEDSTATS
Ingo Molnarcc367732007-10-15 17:00:18 +02002201 if (task_hot(p, rq->clock, sd)) {
Ingo Molnarda84d962007-10-15 17:00:18 +02002202 schedstat_inc(sd, lb_hot_gained[idle]);
Ingo Molnarcc367732007-10-15 17:00:18 +02002203 schedstat_inc(p, se.nr_forced_migrations);
2204 }
Ingo Molnarda84d962007-10-15 17:00:18 +02002205#endif
2206 return 1;
2207 }
2208
Ingo Molnarcc367732007-10-15 17:00:18 +02002209 if (task_hot(p, rq->clock, sd)) {
2210 schedstat_inc(p, se.nr_failed_migrations_hot);
Ingo Molnarda84d962007-10-15 17:00:18 +02002211 return 0;
Ingo Molnarcc367732007-10-15 17:00:18 +02002212 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002213 return 1;
2214}
2215
Ingo Molnardd41f592007-07-09 18:51:59 +02002216static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
2217 unsigned long max_nr_move, unsigned long max_load_move,
2218 struct sched_domain *sd, enum cpu_idle_type idle,
2219 int *all_pinned, unsigned long *load_moved,
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002220 int *this_best_prio, struct rq_iterator *iterator)
Ingo Molnardd41f592007-07-09 18:51:59 +02002221{
2222 int pulled = 0, pinned = 0, skip_for_load;
2223 struct task_struct *p;
2224 long rem_load_move = max_load_move;
2225
2226 if (max_nr_move == 0 || max_load_move == 0)
2227 goto out;
2228
2229 pinned = 1;
2230
2231 /*
2232 * Start the load-balancing iterator:
2233 */
2234 p = iterator->start(iterator->arg);
2235next:
2236 if (!p)
2237 goto out;
2238 /*
2239 * To help distribute high priority tasks accross CPUs we don't
2240 * skip a task if it will be the highest priority task (i.e. smallest
2241 * prio value) on its new queue regardless of its load weight
2242 */
2243 skip_for_load = (p->se.load.weight >> 1) > rem_load_move +
2244 SCHED_LOAD_SCALE_FUZZ;
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002245 if ((skip_for_load && p->prio >= *this_best_prio) ||
Ingo Molnardd41f592007-07-09 18:51:59 +02002246 !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) {
Ingo Molnardd41f592007-07-09 18:51:59 +02002247 p = iterator->next(iterator->arg);
2248 goto next;
2249 }
2250
2251 pull_task(busiest, p, this_rq, this_cpu);
2252 pulled++;
2253 rem_load_move -= p->se.load.weight;
2254
2255 /*
2256 * We only want to steal up to the prescribed number of tasks
2257 * and the prescribed amount of weighted load.
2258 */
2259 if (pulled < max_nr_move && rem_load_move > 0) {
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002260 if (p->prio < *this_best_prio)
2261 *this_best_prio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02002262 p = iterator->next(iterator->arg);
2263 goto next;
2264 }
2265out:
2266 /*
2267 * Right now, this is the only place pull_task() is called,
2268 * so we can safely collect pull_task() stats here rather than
2269 * inside pull_task().
2270 */
2271 schedstat_add(sd, lb_gained[idle], pulled);
2272
2273 if (all_pinned)
2274 *all_pinned = pinned;
2275 *load_moved = max_load_move - rem_load_move;
2276 return pulled;
2277}
Ingo Molnar48f24c42006-07-03 00:25:40 -07002278
Linus Torvalds1da177e2005-04-16 15:20:36 -07002279/*
Peter Williams43010652007-08-09 11:16:46 +02002280 * move_tasks tries to move up to max_load_move weighted load from busiest to
2281 * this_rq, as part of a balancing operation within domain "sd".
2282 * Returns 1 if successful and 0 otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002283 *
2284 * Called with both runqueues locked.
2285 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002286static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
Peter Williams43010652007-08-09 11:16:46 +02002287 unsigned long max_load_move,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002288 struct sched_domain *sd, enum cpu_idle_type idle,
Peter Williams2dd73a42006-06-27 02:54:34 -07002289 int *all_pinned)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002290{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02002291 const struct sched_class *class = sched_class_highest;
Peter Williams43010652007-08-09 11:16:46 +02002292 unsigned long total_load_moved = 0;
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002293 int this_best_prio = this_rq->curr->prio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002294
Ingo Molnardd41f592007-07-09 18:51:59 +02002295 do {
Peter Williams43010652007-08-09 11:16:46 +02002296 total_load_moved +=
2297 class->load_balance(this_rq, this_cpu, busiest,
2298 ULONG_MAX, max_load_move - total_load_moved,
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002299 sd, idle, all_pinned, &this_best_prio);
Ingo Molnardd41f592007-07-09 18:51:59 +02002300 class = class->next;
Peter Williams43010652007-08-09 11:16:46 +02002301 } while (class && max_load_move > total_load_moved);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302
Peter Williams43010652007-08-09 11:16:46 +02002303 return total_load_moved > 0;
2304}
2305
2306/*
2307 * move_one_task tries to move exactly one task from busiest to this_rq, as
2308 * part of active balancing operations within "domain".
2309 * Returns 1 if successful and 0 otherwise.
2310 *
2311 * Called with both runqueues locked.
2312 */
2313static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest,
2314 struct sched_domain *sd, enum cpu_idle_type idle)
2315{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02002316 const struct sched_class *class;
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002317 int this_best_prio = MAX_PRIO;
Peter Williams43010652007-08-09 11:16:46 +02002318
2319 for (class = sched_class_highest; class; class = class->next)
2320 if (class->load_balance(this_rq, this_cpu, busiest,
Peter Williamsa4ac01c2007-08-09 11:16:46 +02002321 1, ULONG_MAX, sd, idle, NULL,
2322 &this_best_prio))
Peter Williams43010652007-08-09 11:16:46 +02002323 return 1;
2324
2325 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002326}
2327
2328/*
2329 * find_busiest_group finds and returns the busiest CPU group within the
Ingo Molnar48f24c42006-07-03 00:25:40 -07002330 * domain. It calculates and returns the amount of weighted load which
2331 * should be moved to restore balance via the imbalance parameter.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002332 */
2333static struct sched_group *
2334find_busiest_group(struct sched_domain *sd, int this_cpu,
Ingo Molnardd41f592007-07-09 18:51:59 +02002335 unsigned long *imbalance, enum cpu_idle_type idle,
2336 int *sd_idle, cpumask_t *cpus, int *balance)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002337{
2338 struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
2339 unsigned long max_load, avg_load, total_load, this_load, total_pwr;
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07002340 unsigned long max_pull;
Peter Williams2dd73a42006-06-27 02:54:34 -07002341 unsigned long busiest_load_per_task, busiest_nr_running;
2342 unsigned long this_load_per_task, this_nr_running;
Ken Chen908a7c12007-10-17 16:55:11 +02002343 int load_idx, group_imb = 0;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002344#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2345 int power_savings_balance = 1;
2346 unsigned long leader_nr_running = 0, min_load_per_task = 0;
2347 unsigned long min_nr_running = ULONG_MAX;
2348 struct sched_group *group_min = NULL, *group_leader = NULL;
2349#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002350
2351 max_load = this_load = total_load = total_pwr = 0;
Peter Williams2dd73a42006-06-27 02:54:34 -07002352 busiest_load_per_task = busiest_nr_running = 0;
2353 this_load_per_task = this_nr_running = 0;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002354 if (idle == CPU_NOT_IDLE)
Nick Piggin78979862005-06-25 14:57:13 -07002355 load_idx = sd->busy_idx;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002356 else if (idle == CPU_NEWLY_IDLE)
Nick Piggin78979862005-06-25 14:57:13 -07002357 load_idx = sd->newidle_idx;
2358 else
2359 load_idx = sd->idle_idx;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002360
2361 do {
Ken Chen908a7c12007-10-17 16:55:11 +02002362 unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002363 int local_group;
2364 int i;
Ken Chen908a7c12007-10-17 16:55:11 +02002365 int __group_imb = 0;
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002366 unsigned int balance_cpu = -1, first_idle_cpu = 0;
Peter Williams2dd73a42006-06-27 02:54:34 -07002367 unsigned long sum_nr_running, sum_weighted_load;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002368
2369 local_group = cpu_isset(this_cpu, group->cpumask);
2370
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002371 if (local_group)
2372 balance_cpu = first_cpu(group->cpumask);
2373
Linus Torvalds1da177e2005-04-16 15:20:36 -07002374 /* Tally up the load of all CPUs in the group */
Peter Williams2dd73a42006-06-27 02:54:34 -07002375 sum_weighted_load = sum_nr_running = avg_load = 0;
Ken Chen908a7c12007-10-17 16:55:11 +02002376 max_cpu_load = 0;
2377 min_cpu_load = ~0UL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002378
2379 for_each_cpu_mask(i, group->cpumask) {
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002380 struct rq *rq;
2381
2382 if (!cpu_isset(i, *cpus))
2383 continue;
2384
2385 rq = cpu_rq(i);
Peter Williams2dd73a42006-06-27 02:54:34 -07002386
Suresh Siddha9439aab2007-07-19 21:28:35 +02002387 if (*sd_idle && rq->nr_running)
Nick Piggin5969fe02005-09-10 00:26:19 -07002388 *sd_idle = 0;
2389
Linus Torvalds1da177e2005-04-16 15:20:36 -07002390 /* Bias balancing toward cpus of our domain */
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002391 if (local_group) {
2392 if (idle_cpu(i) && !first_idle_cpu) {
2393 first_idle_cpu = 1;
2394 balance_cpu = i;
2395 }
2396
Nick Piggina2000572006-02-10 01:51:02 -08002397 load = target_load(i, load_idx);
Ken Chen908a7c12007-10-17 16:55:11 +02002398 } else {
Nick Piggina2000572006-02-10 01:51:02 -08002399 load = source_load(i, load_idx);
Ken Chen908a7c12007-10-17 16:55:11 +02002400 if (load > max_cpu_load)
2401 max_cpu_load = load;
2402 if (min_cpu_load > load)
2403 min_cpu_load = load;
2404 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002405
2406 avg_load += load;
Peter Williams2dd73a42006-06-27 02:54:34 -07002407 sum_nr_running += rq->nr_running;
Ingo Molnardd41f592007-07-09 18:51:59 +02002408 sum_weighted_load += weighted_cpuload(i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002409 }
2410
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002411 /*
2412 * First idle cpu or the first cpu(busiest) in this sched group
2413 * is eligible for doing load balancing at this and above
Suresh Siddha9439aab2007-07-19 21:28:35 +02002414 * domains. In the newly idle case, we will allow all the cpu's
2415 * to do the newly idle load balance.
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002416 */
Suresh Siddha9439aab2007-07-19 21:28:35 +02002417 if (idle != CPU_NEWLY_IDLE && local_group &&
2418 balance_cpu != this_cpu && balance) {
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002419 *balance = 0;
2420 goto ret;
2421 }
2422
Linus Torvalds1da177e2005-04-16 15:20:36 -07002423 total_load += avg_load;
Eric Dumazet5517d862007-05-08 00:32:57 -07002424 total_pwr += group->__cpu_power;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002425
2426 /* Adjust by relative CPU power of the group */
Eric Dumazet5517d862007-05-08 00:32:57 -07002427 avg_load = sg_div_cpu_power(group,
2428 avg_load * SCHED_LOAD_SCALE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002429
Ken Chen908a7c12007-10-17 16:55:11 +02002430 if ((max_cpu_load - min_cpu_load) > SCHED_LOAD_SCALE)
2431 __group_imb = 1;
2432
Eric Dumazet5517d862007-05-08 00:32:57 -07002433 group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002434
Linus Torvalds1da177e2005-04-16 15:20:36 -07002435 if (local_group) {
2436 this_load = avg_load;
2437 this = group;
Peter Williams2dd73a42006-06-27 02:54:34 -07002438 this_nr_running = sum_nr_running;
2439 this_load_per_task = sum_weighted_load;
2440 } else if (avg_load > max_load &&
Ken Chen908a7c12007-10-17 16:55:11 +02002441 (sum_nr_running > group_capacity || __group_imb)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002442 max_load = avg_load;
2443 busiest = group;
Peter Williams2dd73a42006-06-27 02:54:34 -07002444 busiest_nr_running = sum_nr_running;
2445 busiest_load_per_task = sum_weighted_load;
Ken Chen908a7c12007-10-17 16:55:11 +02002446 group_imb = __group_imb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002447 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002448
2449#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
2450 /*
2451 * Busy processors will not participate in power savings
2452 * balance.
2453 */
Ingo Molnardd41f592007-07-09 18:51:59 +02002454 if (idle == CPU_NOT_IDLE ||
2455 !(sd->flags & SD_POWERSAVINGS_BALANCE))
2456 goto group_next;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002457
2458 /*
2459 * If the local group is idle or completely loaded
2460 * no need to do power savings balance at this domain
2461 */
2462 if (local_group && (this_nr_running >= group_capacity ||
2463 !this_nr_running))
2464 power_savings_balance = 0;
2465
Ingo Molnardd41f592007-07-09 18:51:59 +02002466 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002467 * If a group is already running at full capacity or idle,
2468 * don't include that group in power savings calculations
Ingo Molnardd41f592007-07-09 18:51:59 +02002469 */
2470 if (!power_savings_balance || sum_nr_running >= group_capacity
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002471 || !sum_nr_running)
Ingo Molnardd41f592007-07-09 18:51:59 +02002472 goto group_next;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002473
Ingo Molnardd41f592007-07-09 18:51:59 +02002474 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002475 * Calculate the group which has the least non-idle load.
Ingo Molnardd41f592007-07-09 18:51:59 +02002476 * This is the group from where we need to pick up the load
2477 * for saving power
2478 */
2479 if ((sum_nr_running < min_nr_running) ||
2480 (sum_nr_running == min_nr_running &&
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002481 first_cpu(group->cpumask) <
2482 first_cpu(group_min->cpumask))) {
Ingo Molnardd41f592007-07-09 18:51:59 +02002483 group_min = group;
2484 min_nr_running = sum_nr_running;
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002485 min_load_per_task = sum_weighted_load /
2486 sum_nr_running;
Ingo Molnardd41f592007-07-09 18:51:59 +02002487 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002488
Ingo Molnardd41f592007-07-09 18:51:59 +02002489 /*
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002490 * Calculate the group which is almost near its
Ingo Molnardd41f592007-07-09 18:51:59 +02002491 * capacity but still has some space to pick up some load
2492 * from other group and save more power
2493 */
2494 if (sum_nr_running <= group_capacity - 1) {
2495 if (sum_nr_running > leader_nr_running ||
2496 (sum_nr_running == leader_nr_running &&
2497 first_cpu(group->cpumask) >
2498 first_cpu(group_leader->cpumask))) {
2499 group_leader = group;
2500 leader_nr_running = sum_nr_running;
2501 }
Ingo Molnar48f24c42006-07-03 00:25:40 -07002502 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002503group_next:
2504#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07002505 group = group->next;
2506 } while (group != sd->groups);
2507
Peter Williams2dd73a42006-06-27 02:54:34 -07002508 if (!busiest || this_load >= max_load || busiest_nr_running == 0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002509 goto out_balanced;
2510
2511 avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
2512
2513 if (this_load >= avg_load ||
2514 100*max_load <= sd->imbalance_pct*this_load)
2515 goto out_balanced;
2516
Peter Williams2dd73a42006-06-27 02:54:34 -07002517 busiest_load_per_task /= busiest_nr_running;
Ken Chen908a7c12007-10-17 16:55:11 +02002518 if (group_imb)
2519 busiest_load_per_task = min(busiest_load_per_task, avg_load);
2520
Linus Torvalds1da177e2005-04-16 15:20:36 -07002521 /*
2522 * We're trying to get all the cpus to the average_load, so we don't
2523 * want to push ourselves above the average load, nor do we wish to
2524 * reduce the max loaded cpu below the average load, as either of these
2525 * actions would just result in more rebalancing later, and ping-pong
2526 * tasks around. Thus we look for the minimum possible imbalance.
2527 * Negative imbalances (*we* are more loaded than anyone else) will
2528 * be counted as no imbalance for these purposes -- we can't fix that
2529 * by pulling tasks to us. Be careful of negative numbers as they'll
2530 * appear as very large values with unsigned longs.
2531 */
Peter Williams2dd73a42006-06-27 02:54:34 -07002532 if (max_load <= busiest_load_per_task)
2533 goto out_balanced;
2534
2535 /*
2536 * In the presence of smp nice balancing, certain scenarios can have
2537 * max load less than avg load(as we skip the groups at or below
2538 * its cpu_power, while calculating max_load..)
2539 */
2540 if (max_load < avg_load) {
2541 *imbalance = 0;
2542 goto small_imbalance;
2543 }
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07002544
2545 /* Don't want to pull so many tasks that a group would go idle */
Peter Williams2dd73a42006-06-27 02:54:34 -07002546 max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
Siddha, Suresh B0c117f12005-09-10 00:26:21 -07002547
Linus Torvalds1da177e2005-04-16 15:20:36 -07002548 /* How much load to actually move to equalise the imbalance */
Eric Dumazet5517d862007-05-08 00:32:57 -07002549 *imbalance = min(max_pull * busiest->__cpu_power,
2550 (avg_load - this_load) * this->__cpu_power)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002551 / SCHED_LOAD_SCALE;
2552
Peter Williams2dd73a42006-06-27 02:54:34 -07002553 /*
2554 * if *imbalance is less than the average load per runnable task
2555 * there is no gaurantee that any tasks will be moved so we'll have
2556 * a think about bumping its value to force at least one task to be
2557 * moved
2558 */
Suresh Siddha7fd0d2d2007-09-05 14:32:48 +02002559 if (*imbalance < busiest_load_per_task) {
Ingo Molnar48f24c42006-07-03 00:25:40 -07002560 unsigned long tmp, pwr_now, pwr_move;
Peter Williams2dd73a42006-06-27 02:54:34 -07002561 unsigned int imbn;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002562
Peter Williams2dd73a42006-06-27 02:54:34 -07002563small_imbalance:
2564 pwr_move = pwr_now = 0;
2565 imbn = 2;
2566 if (this_nr_running) {
2567 this_load_per_task /= this_nr_running;
2568 if (busiest_load_per_task > this_load_per_task)
2569 imbn = 1;
2570 } else
2571 this_load_per_task = SCHED_LOAD_SCALE;
2572
Ingo Molnardd41f592007-07-09 18:51:59 +02002573 if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
2574 busiest_load_per_task * imbn) {
Peter Williams2dd73a42006-06-27 02:54:34 -07002575 *imbalance = busiest_load_per_task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002576 return busiest;
2577 }
2578
2579 /*
2580 * OK, we don't have enough imbalance to justify moving tasks,
2581 * however we may be able to increase total CPU power used by
2582 * moving them.
2583 */
2584
Eric Dumazet5517d862007-05-08 00:32:57 -07002585 pwr_now += busiest->__cpu_power *
2586 min(busiest_load_per_task, max_load);
2587 pwr_now += this->__cpu_power *
2588 min(this_load_per_task, this_load);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002589 pwr_now /= SCHED_LOAD_SCALE;
2590
2591 /* Amount of load we'd subtract */
Eric Dumazet5517d862007-05-08 00:32:57 -07002592 tmp = sg_div_cpu_power(busiest,
2593 busiest_load_per_task * SCHED_LOAD_SCALE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002594 if (max_load > tmp)
Eric Dumazet5517d862007-05-08 00:32:57 -07002595 pwr_move += busiest->__cpu_power *
Peter Williams2dd73a42006-06-27 02:54:34 -07002596 min(busiest_load_per_task, max_load - tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002597
2598 /* Amount of load we'd add */
Eric Dumazet5517d862007-05-08 00:32:57 -07002599 if (max_load * busiest->__cpu_power <
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08002600 busiest_load_per_task * SCHED_LOAD_SCALE)
Eric Dumazet5517d862007-05-08 00:32:57 -07002601 tmp = sg_div_cpu_power(this,
2602 max_load * busiest->__cpu_power);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002603 else
Eric Dumazet5517d862007-05-08 00:32:57 -07002604 tmp = sg_div_cpu_power(this,
2605 busiest_load_per_task * SCHED_LOAD_SCALE);
2606 pwr_move += this->__cpu_power *
2607 min(this_load_per_task, this_load + tmp);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002608 pwr_move /= SCHED_LOAD_SCALE;
2609
2610 /* Move if we gain throughput */
Suresh Siddha7fd0d2d2007-09-05 14:32:48 +02002611 if (pwr_move > pwr_now)
2612 *imbalance = busiest_load_per_task;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002613 }
2614
Linus Torvalds1da177e2005-04-16 15:20:36 -07002615 return busiest;
2616
2617out_balanced:
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002618#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002619 if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002620 goto ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002621
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002622 if (this == group_leader && group_leader != group_min) {
2623 *imbalance = min_load_per_task;
2624 return group_min;
2625 }
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07002626#endif
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002627ret:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002628 *imbalance = 0;
2629 return NULL;
2630}
2631
2632/*
2633 * find_busiest_queue - find the busiest runqueue among the cpus in group.
2634 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002635static struct rq *
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002636find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle,
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002637 unsigned long imbalance, cpumask_t *cpus)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002638{
Ingo Molnar70b97a72006-07-03 00:25:42 -07002639 struct rq *busiest = NULL, *rq;
Peter Williams2dd73a42006-06-27 02:54:34 -07002640 unsigned long max_load = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002641 int i;
2642
2643 for_each_cpu_mask(i, group->cpumask) {
Ingo Molnardd41f592007-07-09 18:51:59 +02002644 unsigned long wl;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002645
2646 if (!cpu_isset(i, *cpus))
2647 continue;
2648
Ingo Molnar48f24c42006-07-03 00:25:40 -07002649 rq = cpu_rq(i);
Ingo Molnardd41f592007-07-09 18:51:59 +02002650 wl = weighted_cpuload(i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002651
Ingo Molnardd41f592007-07-09 18:51:59 +02002652 if (rq->nr_running == 1 && wl > imbalance)
Peter Williams2dd73a42006-06-27 02:54:34 -07002653 continue;
2654
Ingo Molnardd41f592007-07-09 18:51:59 +02002655 if (wl > max_load) {
2656 max_load = wl;
Ingo Molnar48f24c42006-07-03 00:25:40 -07002657 busiest = rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002658 }
2659 }
2660
2661 return busiest;
2662}
2663
2664/*
Nick Piggin77391d72005-06-25 14:57:30 -07002665 * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but
2666 * so long as it is large enough.
2667 */
2668#define MAX_PINNED_INTERVAL 512
2669
2670/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002671 * Check this_cpu to ensure it is balanced within domain. Attempt to move
2672 * tasks if there is an imbalance.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002673 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002674static int load_balance(int this_cpu, struct rq *this_rq,
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002675 struct sched_domain *sd, enum cpu_idle_type idle,
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002676 int *balance)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002677{
Peter Williams43010652007-08-09 11:16:46 +02002678 int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002679 struct sched_group *group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002680 unsigned long imbalance;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002681 struct rq *busiest;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002682 cpumask_t cpus = CPU_MASK_ALL;
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002683 unsigned long flags;
Nick Piggin5969fe02005-09-10 00:26:19 -07002684
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002685 /*
2686 * When power savings policy is enabled for the parent domain, idle
2687 * sibling can pick up load irrespective of busy siblings. In this case,
Ingo Molnardd41f592007-07-09 18:51:59 +02002688 * let the state of idle sibling percolate up as CPU_IDLE, instead of
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002689 * portraying it as CPU_NOT_IDLE.
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002690 */
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002691 if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002692 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002693 sd_idle = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002694
Ingo Molnar2d723762007-10-15 17:00:12 +02002695 schedstat_inc(sd, lb_count[idle]);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002696
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002697redo:
2698 group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle,
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002699 &cpus, balance);
2700
Chen, Kenneth W06066712006-12-10 02:20:35 -08002701 if (*balance == 0)
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002702 goto out_balanced;
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002703
Linus Torvalds1da177e2005-04-16 15:20:36 -07002704 if (!group) {
2705 schedstat_inc(sd, lb_nobusyg[idle]);
2706 goto out_balanced;
2707 }
2708
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002709 busiest = find_busiest_queue(group, idle, imbalance, &cpus);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002710 if (!busiest) {
2711 schedstat_inc(sd, lb_nobusyq[idle]);
2712 goto out_balanced;
2713 }
2714
Nick Piggindb935db2005-06-25 14:57:11 -07002715 BUG_ON(busiest == this_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002716
2717 schedstat_add(sd, lb_imbalance[idle], imbalance);
2718
Peter Williams43010652007-08-09 11:16:46 +02002719 ld_moved = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002720 if (busiest->nr_running > 1) {
2721 /*
2722 * Attempt to move tasks. If find_busiest_group has found
2723 * an imbalance but busiest->nr_running <= 1, the group is
Peter Williams43010652007-08-09 11:16:46 +02002724 * still unbalanced. ld_moved simply stays zero, so it is
Linus Torvalds1da177e2005-04-16 15:20:36 -07002725 * correctly treated as an imbalance.
2726 */
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002727 local_irq_save(flags);
Nick Piggine17224b2005-09-10 00:26:18 -07002728 double_rq_lock(this_rq, busiest);
Peter Williams43010652007-08-09 11:16:46 +02002729 ld_moved = move_tasks(this_rq, this_cpu, busiest,
Ingo Molnar48f24c42006-07-03 00:25:40 -07002730 imbalance, sd, idle, &all_pinned);
Nick Piggine17224b2005-09-10 00:26:18 -07002731 double_rq_unlock(this_rq, busiest);
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002732 local_irq_restore(flags);
Nick Piggin81026792005-06-25 14:57:07 -07002733
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07002734 /*
2735 * some other cpu did the load balance for us.
2736 */
Peter Williams43010652007-08-09 11:16:46 +02002737 if (ld_moved && this_cpu != smp_processor_id())
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07002738 resched_cpu(this_cpu);
2739
Nick Piggin81026792005-06-25 14:57:07 -07002740 /* All tasks on this runqueue were pinned by CPU affinity */
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002741 if (unlikely(all_pinned)) {
2742 cpu_clear(cpu_of(busiest), cpus);
2743 if (!cpus_empty(cpus))
2744 goto redo;
Nick Piggin81026792005-06-25 14:57:07 -07002745 goto out_balanced;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002746 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002747 }
Nick Piggin81026792005-06-25 14:57:07 -07002748
Peter Williams43010652007-08-09 11:16:46 +02002749 if (!ld_moved) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002750 schedstat_inc(sd, lb_failed[idle]);
2751 sd->nr_balance_failed++;
2752
2753 if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002754
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002755 spin_lock_irqsave(&busiest->lock, flags);
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07002756
2757 /* don't kick the migration_thread, if the curr
2758 * task on busiest cpu can't be moved to this_cpu
2759 */
2760 if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) {
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002761 spin_unlock_irqrestore(&busiest->lock, flags);
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07002762 all_pinned = 1;
2763 goto out_one_pinned;
2764 }
2765
Linus Torvalds1da177e2005-04-16 15:20:36 -07002766 if (!busiest->active_balance) {
2767 busiest->active_balance = 1;
2768 busiest->push_cpu = this_cpu;
Nick Piggin81026792005-06-25 14:57:07 -07002769 active_balance = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002770 }
Christoph Lameterfe2eea32006-12-10 02:20:21 -08002771 spin_unlock_irqrestore(&busiest->lock, flags);
Nick Piggin81026792005-06-25 14:57:07 -07002772 if (active_balance)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002773 wake_up_process(busiest->migration_thread);
2774
2775 /*
2776 * We've kicked active balancing, reset the failure
2777 * counter.
2778 */
Nick Piggin39507452005-06-25 14:57:09 -07002779 sd->nr_balance_failed = sd->cache_nice_tries+1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002780 }
Nick Piggin81026792005-06-25 14:57:07 -07002781 } else
Linus Torvalds1da177e2005-04-16 15:20:36 -07002782 sd->nr_balance_failed = 0;
2783
Nick Piggin81026792005-06-25 14:57:07 -07002784 if (likely(!active_balance)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07002785 /* We were unbalanced, so reset the balancing interval */
2786 sd->balance_interval = sd->min_interval;
Nick Piggin81026792005-06-25 14:57:07 -07002787 } else {
2788 /*
2789 * If we've begun active balancing, start to back off. This
2790 * case may not be covered by the all_pinned logic if there
2791 * is only 1 task on the busy runqueue (because we don't call
2792 * move_tasks).
2793 */
2794 if (sd->balance_interval < sd->max_interval)
2795 sd->balance_interval *= 2;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002796 }
2797
Peter Williams43010652007-08-09 11:16:46 +02002798 if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002799 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002800 return -1;
Peter Williams43010652007-08-09 11:16:46 +02002801 return ld_moved;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002802
2803out_balanced:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002804 schedstat_inc(sd, lb_balanced[idle]);
2805
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002806 sd->nr_balance_failed = 0;
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07002807
2808out_one_pinned:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002809 /* tune up the balancing interval */
Nick Piggin77391d72005-06-25 14:57:30 -07002810 if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) ||
2811 (sd->balance_interval < sd->max_interval))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002812 sd->balance_interval *= 2;
2813
Ingo Molnar48f24c42006-07-03 00:25:40 -07002814 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002815 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002816 return -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002817 return 0;
2818}
2819
2820/*
2821 * Check this_cpu to ensure it is balanced within domain. Attempt to move
2822 * tasks if there is an imbalance.
2823 *
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002824 * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE).
Linus Torvalds1da177e2005-04-16 15:20:36 -07002825 * this_rq is locked.
2826 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07002827static int
Ingo Molnar70b97a72006-07-03 00:25:42 -07002828load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002829{
2830 struct sched_group *group;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002831 struct rq *busiest = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002832 unsigned long imbalance;
Peter Williams43010652007-08-09 11:16:46 +02002833 int ld_moved = 0;
Nick Piggin5969fe02005-09-10 00:26:19 -07002834 int sd_idle = 0;
Suresh Siddha969bb4e2007-07-19 21:28:35 +02002835 int all_pinned = 0;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002836 cpumask_t cpus = CPU_MASK_ALL;
Nick Piggin5969fe02005-09-10 00:26:19 -07002837
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002838 /*
2839 * When power savings policy is enabled for the parent domain, idle
2840 * sibling can pick up load irrespective of busy siblings. In this case,
2841 * let the state of idle sibling percolate up as IDLE, instead of
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002842 * portraying it as CPU_NOT_IDLE.
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002843 */
2844 if (sd->flags & SD_SHARE_CPUPOWER &&
2845 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002846 sd_idle = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002847
Ingo Molnar2d723762007-10-15 17:00:12 +02002848 schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]);
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002849redo:
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002850 group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE,
Siddha, Suresh B783609c2006-12-10 02:20:33 -08002851 &sd_idle, &cpus, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002852 if (!group) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002853 schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]);
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002854 goto out_balanced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002855 }
2856
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002857 busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance,
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002858 &cpus);
Nick Piggindb935db2005-06-25 14:57:11 -07002859 if (!busiest) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002860 schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]);
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002861 goto out_balanced;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002862 }
2863
Nick Piggindb935db2005-06-25 14:57:11 -07002864 BUG_ON(busiest == this_rq);
2865
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002866 schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance);
Nick Piggind6d5cfa2005-09-10 00:26:16 -07002867
Peter Williams43010652007-08-09 11:16:46 +02002868 ld_moved = 0;
Nick Piggind6d5cfa2005-09-10 00:26:16 -07002869 if (busiest->nr_running > 1) {
2870 /* Attempt to move tasks */
2871 double_lock_balance(this_rq, busiest);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02002872 /* this_rq->clock is already updated */
2873 update_rq_clock(busiest);
Peter Williams43010652007-08-09 11:16:46 +02002874 ld_moved = move_tasks(this_rq, this_cpu, busiest,
Suresh Siddha969bb4e2007-07-19 21:28:35 +02002875 imbalance, sd, CPU_NEWLY_IDLE,
2876 &all_pinned);
Nick Piggind6d5cfa2005-09-10 00:26:16 -07002877 spin_unlock(&busiest->lock);
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002878
Suresh Siddha969bb4e2007-07-19 21:28:35 +02002879 if (unlikely(all_pinned)) {
Christoph Lameter0a2966b2006-09-25 23:30:51 -07002880 cpu_clear(cpu_of(busiest), cpus);
2881 if (!cpus_empty(cpus))
2882 goto redo;
2883 }
Nick Piggind6d5cfa2005-09-10 00:26:16 -07002884 }
2885
Peter Williams43010652007-08-09 11:16:46 +02002886 if (!ld_moved) {
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002887 schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002888 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
2889 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002890 return -1;
2891 } else
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002892 sd->nr_balance_failed = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002893
Peter Williams43010652007-08-09 11:16:46 +02002894 return ld_moved;
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002895
2896out_balanced:
Ingo Molnard15bcfd2007-07-09 18:51:57 +02002897 schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]);
Ingo Molnar48f24c42006-07-03 00:25:40 -07002898 if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&
Siddha, Suresh B89c47102006-10-03 01:14:09 -07002899 !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE))
Nick Piggin5969fe02005-09-10 00:26:19 -07002900 return -1;
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002901 sd->nr_balance_failed = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07002902
Nick Piggin16cfb1c2005-06-25 14:57:08 -07002903 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002904}
2905
2906/*
2907 * idle_balance is called by schedule() if this_cpu is about to become
2908 * idle. Attempts to pull tasks from other CPUs.
2909 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002910static void idle_balance(int this_cpu, struct rq *this_rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002911{
2912 struct sched_domain *sd;
Ingo Molnardd41f592007-07-09 18:51:59 +02002913 int pulled_task = -1;
2914 unsigned long next_balance = jiffies + HZ;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002915
2916 for_each_domain(this_cpu, sd) {
Christoph Lameter92c4ca52007-06-23 17:16:33 -07002917 unsigned long interval;
2918
2919 if (!(sd->flags & SD_LOAD_BALANCE))
2920 continue;
2921
2922 if (sd->flags & SD_BALANCE_NEWIDLE)
Ingo Molnar48f24c42006-07-03 00:25:40 -07002923 /* If we've pulled tasks over stop searching: */
Christoph Lameter1bd77f22006-12-10 02:20:27 -08002924 pulled_task = load_balance_newidle(this_cpu,
Christoph Lameter92c4ca52007-06-23 17:16:33 -07002925 this_rq, sd);
2926
2927 interval = msecs_to_jiffies(sd->balance_interval);
2928 if (time_after(next_balance, sd->last_balance + interval))
2929 next_balance = sd->last_balance + interval;
2930 if (pulled_task)
2931 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002932 }
Ingo Molnardd41f592007-07-09 18:51:59 +02002933 if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
Christoph Lameter1bd77f22006-12-10 02:20:27 -08002934 /*
2935 * We are going idle. next_balance may be set based on
2936 * a busy processor. So reset next_balance.
2937 */
2938 this_rq->next_balance = next_balance;
Ingo Molnardd41f592007-07-09 18:51:59 +02002939 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002940}
2941
2942/*
2943 * active_load_balance is run by migration threads. It pushes running tasks
2944 * off the busiest CPU onto idle CPUs. It requires at least 1 task to be
2945 * running on each physical CPU where possible, and avoids physical /
2946 * logical imbalances.
2947 *
2948 * Called with busiest_rq locked.
2949 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07002950static void active_load_balance(struct rq *busiest_rq, int busiest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07002951{
Nick Piggin39507452005-06-25 14:57:09 -07002952 int target_cpu = busiest_rq->push_cpu;
Ingo Molnar70b97a72006-07-03 00:25:42 -07002953 struct sched_domain *sd;
2954 struct rq *target_rq;
Nick Piggin39507452005-06-25 14:57:09 -07002955
Ingo Molnar48f24c42006-07-03 00:25:40 -07002956 /* Is there any task to move? */
Nick Piggin39507452005-06-25 14:57:09 -07002957 if (busiest_rq->nr_running <= 1)
Nick Piggin39507452005-06-25 14:57:09 -07002958 return;
2959
2960 target_rq = cpu_rq(target_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002961
2962 /*
Nick Piggin39507452005-06-25 14:57:09 -07002963 * This condition is "impossible", if it occurs
2964 * we need to fix it. Originally reported by
2965 * Bjorn Helgaas on a 128-cpu setup.
Linus Torvalds1da177e2005-04-16 15:20:36 -07002966 */
Nick Piggin39507452005-06-25 14:57:09 -07002967 BUG_ON(busiest_rq == target_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002968
Nick Piggin39507452005-06-25 14:57:09 -07002969 /* move a task from busiest_rq to target_rq */
2970 double_lock_balance(busiest_rq, target_rq);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02002971 update_rq_clock(busiest_rq);
2972 update_rq_clock(target_rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002973
Nick Piggin39507452005-06-25 14:57:09 -07002974 /* Search for an sd spanning us and the target CPU. */
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002975 for_each_domain(target_cpu, sd) {
Nick Piggin39507452005-06-25 14:57:09 -07002976 if ((sd->flags & SD_LOAD_BALANCE) &&
Ingo Molnar48f24c42006-07-03 00:25:40 -07002977 cpu_isset(busiest_cpu, sd->span))
Nick Piggin39507452005-06-25 14:57:09 -07002978 break;
Chen, Kenneth Wc96d1452006-06-27 02:54:28 -07002979 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07002980
Ingo Molnar48f24c42006-07-03 00:25:40 -07002981 if (likely(sd)) {
Ingo Molnar2d723762007-10-15 17:00:12 +02002982 schedstat_inc(sd, alb_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002983
Peter Williams43010652007-08-09 11:16:46 +02002984 if (move_one_task(target_rq, target_cpu, busiest_rq,
2985 sd, CPU_IDLE))
Ingo Molnar48f24c42006-07-03 00:25:40 -07002986 schedstat_inc(sd, alb_pushed);
2987 else
2988 schedstat_inc(sd, alb_failed);
2989 }
Nick Piggin39507452005-06-25 14:57:09 -07002990 spin_unlock(&target_rq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07002991}
2992
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07002993#ifdef CONFIG_NO_HZ
2994static struct {
2995 atomic_t load_balancer;
2996 cpumask_t cpu_mask;
2997} nohz ____cacheline_aligned = {
2998 .load_balancer = ATOMIC_INIT(-1),
2999 .cpu_mask = CPU_MASK_NONE,
3000};
3001
Christoph Lameter7835b982006-12-10 02:20:22 -08003002/*
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003003 * This routine will try to nominate the ilb (idle load balancing)
3004 * owner among the cpus whose ticks are stopped. ilb owner will do the idle
3005 * load balancing on behalf of all those cpus. If all the cpus in the system
3006 * go into this tickless mode, then there will be no ilb owner (as there is
3007 * no need for one) and all the cpus will sleep till the next wakeup event
3008 * arrives...
Christoph Lameter7835b982006-12-10 02:20:22 -08003009 *
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003010 * For the ilb owner, tick is not stopped. And this tick will be used
3011 * for idle load balancing. ilb owner will still be part of
3012 * nohz.cpu_mask..
3013 *
3014 * While stopping the tick, this cpu will become the ilb owner if there
3015 * is no other owner. And will be the owner till that cpu becomes busy
3016 * or if all cpus in the system stop their ticks at which point
3017 * there is no need for ilb owner.
3018 *
3019 * When the ilb owner becomes busy, it nominates another owner, during the
3020 * next busy scheduler_tick()
3021 */
3022int select_nohz_load_balancer(int stop_tick)
3023{
3024 int cpu = smp_processor_id();
3025
3026 if (stop_tick) {
3027 cpu_set(cpu, nohz.cpu_mask);
3028 cpu_rq(cpu)->in_nohz_recently = 1;
3029
3030 /*
3031 * If we are going offline and still the leader, give up!
3032 */
3033 if (cpu_is_offline(cpu) &&
3034 atomic_read(&nohz.load_balancer) == cpu) {
3035 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3036 BUG();
3037 return 0;
3038 }
3039
3040 /* time for ilb owner also to sleep */
3041 if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3042 if (atomic_read(&nohz.load_balancer) == cpu)
3043 atomic_set(&nohz.load_balancer, -1);
3044 return 0;
3045 }
3046
3047 if (atomic_read(&nohz.load_balancer) == -1) {
3048 /* make me the ilb owner */
3049 if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1)
3050 return 1;
3051 } else if (atomic_read(&nohz.load_balancer) == cpu)
3052 return 1;
3053 } else {
3054 if (!cpu_isset(cpu, nohz.cpu_mask))
3055 return 0;
3056
3057 cpu_clear(cpu, nohz.cpu_mask);
3058
3059 if (atomic_read(&nohz.load_balancer) == cpu)
3060 if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
3061 BUG();
3062 }
3063 return 0;
3064}
3065#endif
3066
3067static DEFINE_SPINLOCK(balancing);
3068
3069/*
Christoph Lameter7835b982006-12-10 02:20:22 -08003070 * It checks each scheduling domain to see if it is due to be balanced,
3071 * and initiates a balancing operation if so.
3072 *
3073 * Balancing parameters are set up in arch_init_sched_domains.
3074 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02003075static void rebalance_domains(int cpu, enum cpu_idle_type idle)
Christoph Lameter7835b982006-12-10 02:20:22 -08003076{
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003077 int balance = 1;
3078 struct rq *rq = cpu_rq(cpu);
Christoph Lameter7835b982006-12-10 02:20:22 -08003079 unsigned long interval;
3080 struct sched_domain *sd;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003081 /* Earliest time when we have to do rebalance again */
Christoph Lameterc9819f42006-12-10 02:20:25 -08003082 unsigned long next_balance = jiffies + 60*HZ;
Suresh Siddhaf549da82007-08-23 15:18:02 +02003083 int update_next_balance = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003084
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003085 for_each_domain(cpu, sd) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003086 if (!(sd->flags & SD_LOAD_BALANCE))
3087 continue;
3088
3089 interval = sd->balance_interval;
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003090 if (idle != CPU_IDLE)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003091 interval *= sd->busy_factor;
3092
3093 /* scale ms to jiffies */
3094 interval = msecs_to_jiffies(interval);
3095 if (unlikely(!interval))
3096 interval = 1;
Ingo Molnardd41f592007-07-09 18:51:59 +02003097 if (interval > HZ*NR_CPUS/10)
3098 interval = HZ*NR_CPUS/10;
3099
Linus Torvalds1da177e2005-04-16 15:20:36 -07003100
Christoph Lameter08c183f2006-12-10 02:20:29 -08003101 if (sd->flags & SD_SERIALIZE) {
3102 if (!spin_trylock(&balancing))
3103 goto out;
3104 }
3105
Christoph Lameterc9819f42006-12-10 02:20:25 -08003106 if (time_after_eq(jiffies, sd->last_balance + interval)) {
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003107 if (load_balance(cpu, rq, sd, idle, &balance)) {
Siddha, Suresh Bfa3b6dd2005-09-10 00:26:21 -07003108 /*
3109 * We've pulled tasks over so either we're no
Nick Piggin5969fe02005-09-10 00:26:19 -07003110 * longer idle, or one of our SMT siblings is
3111 * not idle.
3112 */
Ingo Molnard15bcfd2007-07-09 18:51:57 +02003113 idle = CPU_NOT_IDLE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003114 }
Christoph Lameter1bd77f22006-12-10 02:20:27 -08003115 sd->last_balance = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003116 }
Christoph Lameter08c183f2006-12-10 02:20:29 -08003117 if (sd->flags & SD_SERIALIZE)
3118 spin_unlock(&balancing);
3119out:
Suresh Siddhaf549da82007-08-23 15:18:02 +02003120 if (time_after(next_balance, sd->last_balance + interval)) {
Christoph Lameterc9819f42006-12-10 02:20:25 -08003121 next_balance = sd->last_balance + interval;
Suresh Siddhaf549da82007-08-23 15:18:02 +02003122 update_next_balance = 1;
3123 }
Siddha, Suresh B783609c2006-12-10 02:20:33 -08003124
3125 /*
3126 * Stop the load balance at this level. There is another
3127 * CPU in our sched group which is doing load balancing more
3128 * actively.
3129 */
3130 if (!balance)
3131 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003132 }
Suresh Siddhaf549da82007-08-23 15:18:02 +02003133
3134 /*
3135 * next_balance will be updated only when there is a need.
3136 * When the cpu is attached to null domain for ex, it will not be
3137 * updated.
3138 */
3139 if (likely(update_next_balance))
3140 rq->next_balance = next_balance;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003141}
3142
3143/*
3144 * run_rebalance_domains is triggered when needed from the scheduler tick.
3145 * In CONFIG_NO_HZ case, the idle load balance owner will do the
3146 * rebalancing for all the cpus for whom scheduler ticks are stopped.
3147 */
3148static void run_rebalance_domains(struct softirq_action *h)
3149{
Ingo Molnardd41f592007-07-09 18:51:59 +02003150 int this_cpu = smp_processor_id();
3151 struct rq *this_rq = cpu_rq(this_cpu);
3152 enum cpu_idle_type idle = this_rq->idle_at_tick ?
3153 CPU_IDLE : CPU_NOT_IDLE;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003154
Ingo Molnardd41f592007-07-09 18:51:59 +02003155 rebalance_domains(this_cpu, idle);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003156
3157#ifdef CONFIG_NO_HZ
3158 /*
3159 * If this cpu is the owner for idle load balancing, then do the
3160 * balancing on behalf of the other idle cpus whose ticks are
3161 * stopped.
3162 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003163 if (this_rq->idle_at_tick &&
3164 atomic_read(&nohz.load_balancer) == this_cpu) {
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003165 cpumask_t cpus = nohz.cpu_mask;
3166 struct rq *rq;
3167 int balance_cpu;
3168
Ingo Molnardd41f592007-07-09 18:51:59 +02003169 cpu_clear(this_cpu, cpus);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003170 for_each_cpu_mask(balance_cpu, cpus) {
3171 /*
3172 * If this cpu gets work to do, stop the load balancing
3173 * work being done for other cpus. Next load
3174 * balancing owner will pick it up.
3175 */
3176 if (need_resched())
3177 break;
3178
Oleg Nesterovde0cf892007-08-12 18:08:19 +02003179 rebalance_domains(balance_cpu, CPU_IDLE);
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003180
3181 rq = cpu_rq(balance_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02003182 if (time_after(this_rq->next_balance, rq->next_balance))
3183 this_rq->next_balance = rq->next_balance;
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003184 }
3185 }
3186#endif
3187}
3188
3189/*
3190 * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
3191 *
3192 * In case of CONFIG_NO_HZ, this is the place where we nominate a new
3193 * idle load balancing owner or decide to stop the periodic load balancing,
3194 * if the whole system is idle.
3195 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003196static inline void trigger_load_balance(struct rq *rq, int cpu)
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003197{
Siddha, Suresh B46cb4b72007-05-08 00:32:51 -07003198#ifdef CONFIG_NO_HZ
3199 /*
3200 * If we were in the nohz mode recently and busy at the current
3201 * scheduler tick, then check if we need to nominate new idle
3202 * load balancer.
3203 */
3204 if (rq->in_nohz_recently && !rq->idle_at_tick) {
3205 rq->in_nohz_recently = 0;
3206
3207 if (atomic_read(&nohz.load_balancer) == cpu) {
3208 cpu_clear(cpu, nohz.cpu_mask);
3209 atomic_set(&nohz.load_balancer, -1);
3210 }
3211
3212 if (atomic_read(&nohz.load_balancer) == -1) {
3213 /*
3214 * simple selection for now: Nominate the
3215 * first cpu in the nohz list to be the next
3216 * ilb owner.
3217 *
3218 * TBD: Traverse the sched domains and nominate
3219 * the nearest cpu in the nohz.cpu_mask.
3220 */
3221 int ilb = first_cpu(nohz.cpu_mask);
3222
3223 if (ilb != NR_CPUS)
3224 resched_cpu(ilb);
3225 }
3226 }
3227
3228 /*
3229 * If this cpu is idle and doing idle load balancing for all the
3230 * cpus with ticks stopped, is it time for that to stop?
3231 */
3232 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu &&
3233 cpus_weight(nohz.cpu_mask) == num_online_cpus()) {
3234 resched_cpu(cpu);
3235 return;
3236 }
3237
3238 /*
3239 * If this cpu is idle and the idle load balancing is done by
3240 * someone else, then no need raise the SCHED_SOFTIRQ
3241 */
3242 if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu &&
3243 cpu_isset(cpu, nohz.cpu_mask))
3244 return;
3245#endif
3246 if (time_after_eq(jiffies, rq->next_balance))
3247 raise_softirq(SCHED_SOFTIRQ);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003248}
Ingo Molnardd41f592007-07-09 18:51:59 +02003249
3250#else /* CONFIG_SMP */
3251
Linus Torvalds1da177e2005-04-16 15:20:36 -07003252/*
3253 * on UP we do not need to balance between CPUs:
3254 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07003255static inline void idle_balance(int cpu, struct rq *rq)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003256{
3257}
Ingo Molnardd41f592007-07-09 18:51:59 +02003258
3259/* Avoid "used but not defined" warning on UP */
3260static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest,
3261 unsigned long max_nr_move, unsigned long max_load_move,
3262 struct sched_domain *sd, enum cpu_idle_type idle,
3263 int *all_pinned, unsigned long *load_moved,
Peter Williamsa4ac01c2007-08-09 11:16:46 +02003264 int *this_best_prio, struct rq_iterator *iterator)
Ingo Molnardd41f592007-07-09 18:51:59 +02003265{
3266 *load_moved = 0;
3267
3268 return 0;
3269}
3270
Linus Torvalds1da177e2005-04-16 15:20:36 -07003271#endif
3272
Linus Torvalds1da177e2005-04-16 15:20:36 -07003273DEFINE_PER_CPU(struct kernel_stat, kstat);
3274
3275EXPORT_PER_CPU_SYMBOL(kstat);
3276
3277/*
Ingo Molnar41b86e92007-07-09 18:51:58 +02003278 * Return p->sum_exec_runtime plus any more ns on the sched_clock
3279 * that have not yet been banked in case the task is currently running.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003280 */
Ingo Molnar41b86e92007-07-09 18:51:58 +02003281unsigned long long task_sched_runtime(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003282{
Linus Torvalds1da177e2005-04-16 15:20:36 -07003283 unsigned long flags;
Ingo Molnar41b86e92007-07-09 18:51:58 +02003284 u64 ns, delta_exec;
3285 struct rq *rq;
Ingo Molnar48f24c42006-07-03 00:25:40 -07003286
Ingo Molnar41b86e92007-07-09 18:51:58 +02003287 rq = task_rq_lock(p, &flags);
3288 ns = p->se.sum_exec_runtime;
3289 if (rq->curr == p) {
Ingo Molnara8e504d2007-08-09 11:16:47 +02003290 update_rq_clock(rq);
3291 delta_exec = rq->clock - p->se.exec_start;
Ingo Molnar41b86e92007-07-09 18:51:58 +02003292 if ((s64)delta_exec > 0)
3293 ns += delta_exec;
3294 }
3295 task_rq_unlock(rq, &flags);
Ingo Molnar48f24c42006-07-03 00:25:40 -07003296
Linus Torvalds1da177e2005-04-16 15:20:36 -07003297 return ns;
3298}
3299
3300/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003301 * Account user cpu time to a process.
3302 * @p: the process that the cpu time gets accounted to
3303 * @hardirq_offset: the offset to subtract from hardirq_count()
3304 * @cputime: the cpu time spent in user space since the last update
3305 */
3306void account_user_time(struct task_struct *p, cputime_t cputime)
3307{
3308 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3309 cputime64_t tmp;
3310
3311 p->utime = cputime_add(p->utime, cputime);
3312
3313 /* Add user time to cpustat. */
3314 tmp = cputime_to_cputime64(cputime);
3315 if (TASK_NICE(p) > 0)
3316 cpustat->nice = cputime64_add(cpustat->nice, tmp);
3317 else
3318 cpustat->user = cputime64_add(cpustat->user, tmp);
3319}
3320
3321/*
Laurent Vivier94886b82007-10-15 17:00:19 +02003322 * Account guest cpu time to a process.
3323 * @p: the process that the cpu time gets accounted to
3324 * @cputime: the cpu time spent in virtual machine since the last update
3325 */
3326void account_guest_time(struct task_struct *p, cputime_t cputime)
3327{
3328 cputime64_t tmp;
3329 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3330
3331 tmp = cputime_to_cputime64(cputime);
3332
3333 p->utime = cputime_add(p->utime, cputime);
3334 p->gtime = cputime_add(p->gtime, cputime);
3335
3336 cpustat->user = cputime64_add(cpustat->user, tmp);
3337 cpustat->guest = cputime64_add(cpustat->guest, tmp);
3338}
3339
3340/*
Michael Neulingc66f08b2007-10-18 03:06:34 -07003341 * Account scaled user cpu time to a process.
3342 * @p: the process that the cpu time gets accounted to
3343 * @cputime: the cpu time spent in user space since the last update
3344 */
3345void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
3346{
3347 p->utimescaled = cputime_add(p->utimescaled, cputime);
3348}
3349
3350/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003351 * Account system cpu time to a process.
3352 * @p: the process that the cpu time gets accounted to
3353 * @hardirq_offset: the offset to subtract from hardirq_count()
3354 * @cputime: the cpu time spent in kernel space since the last update
3355 */
3356void account_system_time(struct task_struct *p, int hardirq_offset,
3357 cputime_t cputime)
3358{
3359 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003360 struct rq *rq = this_rq();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003361 cputime64_t tmp;
3362
Laurent Vivier94886b82007-10-15 17:00:19 +02003363 if (p->flags & PF_VCPU) {
3364 account_guest_time(p, cputime);
3365 p->flags &= ~PF_VCPU;
3366 return;
3367 }
3368
Linus Torvalds1da177e2005-04-16 15:20:36 -07003369 p->stime = cputime_add(p->stime, cputime);
3370
3371 /* Add system time to cpustat. */
3372 tmp = cputime_to_cputime64(cputime);
3373 if (hardirq_count() - hardirq_offset)
3374 cpustat->irq = cputime64_add(cpustat->irq, tmp);
3375 else if (softirq_count())
3376 cpustat->softirq = cputime64_add(cpustat->softirq, tmp);
3377 else if (p != rq->idle)
3378 cpustat->system = cputime64_add(cpustat->system, tmp);
3379 else if (atomic_read(&rq->nr_iowait) > 0)
3380 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
3381 else
3382 cpustat->idle = cputime64_add(cpustat->idle, tmp);
3383 /* Account for system time used */
3384 acct_update_integrals(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003385}
3386
3387/*
Michael Neulingc66f08b2007-10-18 03:06:34 -07003388 * Account scaled system cpu time to a process.
3389 * @p: the process that the cpu time gets accounted to
3390 * @hardirq_offset: the offset to subtract from hardirq_count()
3391 * @cputime: the cpu time spent in kernel space since the last update
3392 */
3393void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
3394{
3395 p->stimescaled = cputime_add(p->stimescaled, cputime);
3396}
3397
3398/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07003399 * Account for involuntary wait time.
3400 * @p: the process from which the cpu time has been stolen
3401 * @steal: the cpu time spent in involuntary wait
3402 */
3403void account_steal_time(struct task_struct *p, cputime_t steal)
3404{
3405 struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
3406 cputime64_t tmp = cputime_to_cputime64(steal);
Ingo Molnar70b97a72006-07-03 00:25:42 -07003407 struct rq *rq = this_rq();
Linus Torvalds1da177e2005-04-16 15:20:36 -07003408
3409 if (p == rq->idle) {
3410 p->stime = cputime_add(p->stime, steal);
3411 if (atomic_read(&rq->nr_iowait) > 0)
3412 cpustat->iowait = cputime64_add(cpustat->iowait, tmp);
3413 else
3414 cpustat->idle = cputime64_add(cpustat->idle, tmp);
3415 } else
3416 cpustat->steal = cputime64_add(cpustat->steal, tmp);
3417}
3418
Christoph Lameter7835b982006-12-10 02:20:22 -08003419/*
3420 * This function gets called by the timer code, with HZ frequency.
3421 * We call it with interrupts disabled.
3422 *
3423 * It also gets called by the fork code, when changing the parent's
3424 * timeslices.
3425 */
3426void scheduler_tick(void)
3427{
Christoph Lameter7835b982006-12-10 02:20:22 -08003428 int cpu = smp_processor_id();
3429 struct rq *rq = cpu_rq(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02003430 struct task_struct *curr = rq->curr;
Ingo Molnar529c7722007-08-10 23:05:11 +02003431 u64 next_tick = rq->tick_timestamp + TICK_NSEC;
Christoph Lameter7835b982006-12-10 02:20:22 -08003432
Ingo Molnardd41f592007-07-09 18:51:59 +02003433 spin_lock(&rq->lock);
Ingo Molnar546fe3c2007-08-09 11:16:51 +02003434 __update_rq_clock(rq);
Ingo Molnar529c7722007-08-10 23:05:11 +02003435 /*
3436 * Let rq->clock advance by at least TICK_NSEC:
3437 */
3438 if (unlikely(rq->clock < next_tick))
3439 rq->clock = next_tick;
3440 rq->tick_timestamp = rq->clock;
Ingo Molnarf1a438d2007-08-09 11:16:45 +02003441 update_cpu_load(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02003442 if (curr != rq->idle) /* FIXME: needed? */
3443 curr->sched_class->task_tick(rq, curr);
Ingo Molnardd41f592007-07-09 18:51:59 +02003444 spin_unlock(&rq->lock);
3445
Christoph Lametere418e1c2006-12-10 02:20:23 -08003446#ifdef CONFIG_SMP
Ingo Molnardd41f592007-07-09 18:51:59 +02003447 rq->idle_at_tick = idle_cpu(cpu);
3448 trigger_load_balance(rq, cpu);
Christoph Lametere418e1c2006-12-10 02:20:23 -08003449#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07003450}
3451
Linus Torvalds1da177e2005-04-16 15:20:36 -07003452#if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT)
3453
3454void fastcall add_preempt_count(int val)
3455{
3456 /*
3457 * Underflow?
3458 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07003459 if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0)))
3460 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003461 preempt_count() += val;
3462 /*
3463 * Spinlock count overflowing soon?
3464 */
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08003465 DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >=
3466 PREEMPT_MASK - 10);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003467}
3468EXPORT_SYMBOL(add_preempt_count);
3469
3470void fastcall sub_preempt_count(int val)
3471{
3472 /*
3473 * Underflow?
3474 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07003475 if (DEBUG_LOCKS_WARN_ON(val > preempt_count()))
3476 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003477 /*
3478 * Is the spinlock portion underflowing?
3479 */
Ingo Molnar9a11b49a2006-07-03 00:24:33 -07003480 if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) &&
3481 !(preempt_count() & PREEMPT_MASK)))
3482 return;
3483
Linus Torvalds1da177e2005-04-16 15:20:36 -07003484 preempt_count() -= val;
3485}
3486EXPORT_SYMBOL(sub_preempt_count);
3487
3488#endif
3489
3490/*
Ingo Molnardd41f592007-07-09 18:51:59 +02003491 * Print scheduling while atomic bug:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003492 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003493static noinline void __schedule_bug(struct task_struct *prev)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003494{
Ingo Molnardd41f592007-07-09 18:51:59 +02003495 printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n",
3496 prev->comm, preempt_count(), prev->pid);
3497 debug_show_held_locks(prev);
3498 if (irqs_disabled())
3499 print_irqtrace_events(prev);
3500 dump_stack();
3501}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003502
Ingo Molnardd41f592007-07-09 18:51:59 +02003503/*
3504 * Various schedule()-time debugging checks and statistics:
3505 */
3506static inline void schedule_debug(struct task_struct *prev)
3507{
Linus Torvalds1da177e2005-04-16 15:20:36 -07003508 /*
3509 * Test if we are atomic. Since do_exit() needs to call into
3510 * schedule() atomically, we ignore that path for now.
3511 * Otherwise, whine if we are scheduling when we should not be.
3512 */
Ingo Molnardd41f592007-07-09 18:51:59 +02003513 if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state))
3514 __schedule_bug(prev);
3515
Linus Torvalds1da177e2005-04-16 15:20:36 -07003516 profile_hit(SCHED_PROFILING, __builtin_return_address(0));
3517
Ingo Molnar2d723762007-10-15 17:00:12 +02003518 schedstat_inc(this_rq(), sched_count);
Ingo Molnarb8efb562007-10-15 17:00:10 +02003519#ifdef CONFIG_SCHEDSTATS
3520 if (unlikely(prev->lock_depth >= 0)) {
Ingo Molnar2d723762007-10-15 17:00:12 +02003521 schedstat_inc(this_rq(), bkl_count);
3522 schedstat_inc(prev, sched_info.bkl_count);
Ingo Molnarb8efb562007-10-15 17:00:10 +02003523 }
3524#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02003525}
3526
3527/*
3528 * Pick up the highest-prio task:
3529 */
3530static inline struct task_struct *
Ingo Molnarff95f3d2007-08-09 11:16:49 +02003531pick_next_task(struct rq *rq, struct task_struct *prev)
Ingo Molnardd41f592007-07-09 18:51:59 +02003532{
Ingo Molnar5522d5d2007-10-15 17:00:12 +02003533 const struct sched_class *class;
Ingo Molnardd41f592007-07-09 18:51:59 +02003534 struct task_struct *p;
3535
3536 /*
3537 * Optimization: we know that if all tasks are in
3538 * the fair class we can call that function directly:
3539 */
3540 if (likely(rq->nr_running == rq->cfs.nr_running)) {
Ingo Molnarfb8d4722007-08-09 11:16:48 +02003541 p = fair_sched_class.pick_next_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02003542 if (likely(p))
3543 return p;
3544 }
3545
3546 class = sched_class_highest;
3547 for ( ; ; ) {
Ingo Molnarfb8d4722007-08-09 11:16:48 +02003548 p = class->pick_next_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02003549 if (p)
3550 return p;
3551 /*
3552 * Will never be NULL as the idle class always
3553 * returns a non-NULL p:
3554 */
3555 class = class->next;
3556 }
3557}
3558
3559/*
3560 * schedule() is the main scheduler function.
3561 */
3562asmlinkage void __sched schedule(void)
3563{
3564 struct task_struct *prev, *next;
3565 long *switch_count;
3566 struct rq *rq;
Ingo Molnardd41f592007-07-09 18:51:59 +02003567 int cpu;
3568
Linus Torvalds1da177e2005-04-16 15:20:36 -07003569need_resched:
3570 preempt_disable();
Ingo Molnardd41f592007-07-09 18:51:59 +02003571 cpu = smp_processor_id();
3572 rq = cpu_rq(cpu);
3573 rcu_qsctr_inc(cpu);
3574 prev = rq->curr;
3575 switch_count = &prev->nivcsw;
3576
Linus Torvalds1da177e2005-04-16 15:20:36 -07003577 release_kernel_lock(prev);
3578need_resched_nonpreemptible:
Linus Torvalds1da177e2005-04-16 15:20:36 -07003579
Ingo Molnardd41f592007-07-09 18:51:59 +02003580 schedule_debug(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003581
Ingo Molnar1e819952007-10-15 17:00:13 +02003582 /*
3583 * Do the rq-clock update outside the rq lock:
3584 */
3585 local_irq_disable();
Ingo Molnarc1b3da32007-08-09 11:16:47 +02003586 __update_rq_clock(rq);
Ingo Molnar1e819952007-10-15 17:00:13 +02003587 spin_lock(&rq->lock);
3588 clear_tsk_need_resched(prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003589
Ingo Molnardd41f592007-07-09 18:51:59 +02003590 if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) {
3591 if (unlikely((prev->state & TASK_INTERRUPTIBLE) &&
3592 unlikely(signal_pending(prev)))) {
3593 prev->state = TASK_RUNNING;
3594 } else {
Ingo Molnar2e1cb742007-08-09 11:16:49 +02003595 deactivate_task(rq, prev, 1);
Ingo Molnardd41f592007-07-09 18:51:59 +02003596 }
3597 switch_count = &prev->nvcsw;
3598 }
3599
3600 if (unlikely(!rq->nr_running))
3601 idle_balance(cpu, rq);
3602
Ingo Molnar31ee5292007-08-09 11:16:49 +02003603 prev->sched_class->put_prev_task(rq, prev);
Ingo Molnarff95f3d2007-08-09 11:16:49 +02003604 next = pick_next_task(rq, prev);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003605
3606 sched_info_switch(prev, next);
Ingo Molnardd41f592007-07-09 18:51:59 +02003607
Linus Torvalds1da177e2005-04-16 15:20:36 -07003608 if (likely(prev != next)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07003609 rq->nr_switches++;
3610 rq->curr = next;
3611 ++*switch_count;
3612
Ingo Molnardd41f592007-07-09 18:51:59 +02003613 context_switch(rq, prev, next); /* unlocks the rq */
Linus Torvalds1da177e2005-04-16 15:20:36 -07003614 } else
3615 spin_unlock_irq(&rq->lock);
3616
Ingo Molnardd41f592007-07-09 18:51:59 +02003617 if (unlikely(reacquire_kernel_lock(current) < 0)) {
3618 cpu = smp_processor_id();
3619 rq = cpu_rq(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003620 goto need_resched_nonpreemptible;
Ingo Molnardd41f592007-07-09 18:51:59 +02003621 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003622 preempt_enable_no_resched();
3623 if (unlikely(test_thread_flag(TIF_NEED_RESCHED)))
3624 goto need_resched;
3625}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003626EXPORT_SYMBOL(schedule);
3627
3628#ifdef CONFIG_PREEMPT
3629/*
Andreas Mohr2ed6e342006-07-10 04:43:52 -07003630 * this is the entry point to schedule() from in-kernel preemption
Linus Torvalds1da177e2005-04-16 15:20:36 -07003631 * off of preempt_enable. Kernel preemptions off return from interrupt
3632 * occur there and call schedule directly.
3633 */
3634asmlinkage void __sched preempt_schedule(void)
3635{
3636 struct thread_info *ti = current_thread_info();
3637#ifdef CONFIG_PREEMPT_BKL
3638 struct task_struct *task = current;
3639 int saved_lock_depth;
3640#endif
3641 /*
3642 * If there is a non-zero preempt_count or interrupts are disabled,
3643 * we do not want to preempt the current task. Just return..
3644 */
Nick Pigginbeed33a2006-10-11 01:21:52 -07003645 if (likely(ti->preempt_count || irqs_disabled()))
Linus Torvalds1da177e2005-04-16 15:20:36 -07003646 return;
3647
Andi Kleen3a5c3592007-10-15 17:00:14 +02003648 do {
3649 add_preempt_count(PREEMPT_ACTIVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003650
Andi Kleen3a5c3592007-10-15 17:00:14 +02003651 /*
3652 * We keep the big kernel semaphore locked, but we
3653 * clear ->lock_depth so that schedule() doesnt
3654 * auto-release the semaphore:
3655 */
3656#ifdef CONFIG_PREEMPT_BKL
3657 saved_lock_depth = task->lock_depth;
3658 task->lock_depth = -1;
3659#endif
3660 schedule();
3661#ifdef CONFIG_PREEMPT_BKL
3662 task->lock_depth = saved_lock_depth;
3663#endif
3664 sub_preempt_count(PREEMPT_ACTIVE);
3665
3666 /*
3667 * Check again in case we missed a preemption opportunity
3668 * between schedule and now.
3669 */
3670 barrier();
3671 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07003672}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003673EXPORT_SYMBOL(preempt_schedule);
3674
3675/*
Andreas Mohr2ed6e342006-07-10 04:43:52 -07003676 * this is the entry point to schedule() from kernel preemption
Linus Torvalds1da177e2005-04-16 15:20:36 -07003677 * off of irq context.
3678 * Note, that this is called and return with irqs disabled. This will
3679 * protect us against recursive calling from irq.
3680 */
3681asmlinkage void __sched preempt_schedule_irq(void)
3682{
3683 struct thread_info *ti = current_thread_info();
3684#ifdef CONFIG_PREEMPT_BKL
3685 struct task_struct *task = current;
3686 int saved_lock_depth;
3687#endif
Andreas Mohr2ed6e342006-07-10 04:43:52 -07003688 /* Catch callers which need to be fixed */
Linus Torvalds1da177e2005-04-16 15:20:36 -07003689 BUG_ON(ti->preempt_count || !irqs_disabled());
3690
Andi Kleen3a5c3592007-10-15 17:00:14 +02003691 do {
3692 add_preempt_count(PREEMPT_ACTIVE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003693
Andi Kleen3a5c3592007-10-15 17:00:14 +02003694 /*
3695 * We keep the big kernel semaphore locked, but we
3696 * clear ->lock_depth so that schedule() doesnt
3697 * auto-release the semaphore:
3698 */
3699#ifdef CONFIG_PREEMPT_BKL
3700 saved_lock_depth = task->lock_depth;
3701 task->lock_depth = -1;
3702#endif
3703 local_irq_enable();
3704 schedule();
3705 local_irq_disable();
3706#ifdef CONFIG_PREEMPT_BKL
3707 task->lock_depth = saved_lock_depth;
3708#endif
3709 sub_preempt_count(PREEMPT_ACTIVE);
3710
3711 /*
3712 * Check again in case we missed a preemption opportunity
3713 * between schedule and now.
3714 */
3715 barrier();
3716 } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
Linus Torvalds1da177e2005-04-16 15:20:36 -07003717}
3718
3719#endif /* CONFIG_PREEMPT */
3720
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07003721int default_wake_function(wait_queue_t *curr, unsigned mode, int sync,
3722 void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003723{
Ingo Molnar48f24c42006-07-03 00:25:40 -07003724 return try_to_wake_up(curr->private, mode, sync);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003725}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003726EXPORT_SYMBOL(default_wake_function);
3727
3728/*
3729 * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just
3730 * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve
3731 * number) then we wake all the non-exclusive tasks and one exclusive task.
3732 *
3733 * There are circumstances in which we can try to wake a task which has already
3734 * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns
3735 * zero in this (rare) case, and we handle it by continuing to scan the queue.
3736 */
3737static void __wake_up_common(wait_queue_head_t *q, unsigned int mode,
3738 int nr_exclusive, int sync, void *key)
3739{
Matthias Kaehlcke2e458742007-10-15 17:00:02 +02003740 wait_queue_t *curr, *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003741
Matthias Kaehlcke2e458742007-10-15 17:00:02 +02003742 list_for_each_entry_safe(curr, next, &q->task_list, task_list) {
Ingo Molnar48f24c42006-07-03 00:25:40 -07003743 unsigned flags = curr->flags;
3744
Linus Torvalds1da177e2005-04-16 15:20:36 -07003745 if (curr->func(curr, mode, sync, key) &&
Ingo Molnar48f24c42006-07-03 00:25:40 -07003746 (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003747 break;
3748 }
3749}
3750
3751/**
3752 * __wake_up - wake up threads blocked on a waitqueue.
3753 * @q: the waitqueue
3754 * @mode: which threads
3755 * @nr_exclusive: how many wake-one or wake-many threads to wake up
Martin Waitz67be2dd2005-05-01 08:59:26 -07003756 * @key: is directly passed to the wakeup function
Linus Torvalds1da177e2005-04-16 15:20:36 -07003757 */
3758void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode,
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07003759 int nr_exclusive, void *key)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003760{
3761 unsigned long flags;
3762
3763 spin_lock_irqsave(&q->lock, flags);
3764 __wake_up_common(q, mode, nr_exclusive, 0, key);
3765 spin_unlock_irqrestore(&q->lock, flags);
3766}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003767EXPORT_SYMBOL(__wake_up);
3768
3769/*
3770 * Same as __wake_up but called with the spinlock in wait_queue_head_t held.
3771 */
3772void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode)
3773{
3774 __wake_up_common(q, mode, 1, 0, NULL);
3775}
3776
3777/**
Martin Waitz67be2dd2005-05-01 08:59:26 -07003778 * __wake_up_sync - wake up threads blocked on a waitqueue.
Linus Torvalds1da177e2005-04-16 15:20:36 -07003779 * @q: the waitqueue
3780 * @mode: which threads
3781 * @nr_exclusive: how many wake-one or wake-many threads to wake up
3782 *
3783 * The sync wakeup differs that the waker knows that it will schedule
3784 * away soon, so while the target thread will be woken up, it will not
3785 * be migrated to another CPU - ie. the two threads are 'synchronized'
3786 * with each other. This can prevent needless bouncing between CPUs.
3787 *
3788 * On UP it can prevent extra preemption.
3789 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07003790void fastcall
3791__wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003792{
3793 unsigned long flags;
3794 int sync = 1;
3795
3796 if (unlikely(!q))
3797 return;
3798
3799 if (unlikely(!nr_exclusive))
3800 sync = 0;
3801
3802 spin_lock_irqsave(&q->lock, flags);
3803 __wake_up_common(q, mode, nr_exclusive, sync, NULL);
3804 spin_unlock_irqrestore(&q->lock, flags);
3805}
3806EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
3807
3808void fastcall complete(struct completion *x)
3809{
3810 unsigned long flags;
3811
3812 spin_lock_irqsave(&x->wait.lock, flags);
3813 x->done++;
3814 __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
3815 1, 0, NULL);
3816 spin_unlock_irqrestore(&x->wait.lock, flags);
3817}
3818EXPORT_SYMBOL(complete);
3819
3820void fastcall complete_all(struct completion *x)
3821{
3822 unsigned long flags;
3823
3824 spin_lock_irqsave(&x->wait.lock, flags);
3825 x->done += UINT_MAX/2;
3826 __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE,
3827 0, 0, NULL);
3828 spin_unlock_irqrestore(&x->wait.lock, flags);
3829}
3830EXPORT_SYMBOL(complete_all);
3831
Andi Kleen8cbbe862007-10-15 17:00:14 +02003832static inline long __sched
3833do_wait_for_common(struct completion *x, long timeout, int state)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003834{
Linus Torvalds1da177e2005-04-16 15:20:36 -07003835 if (!x->done) {
3836 DECLARE_WAITQUEUE(wait, current);
3837
3838 wait.flags |= WQ_FLAG_EXCLUSIVE;
3839 __add_wait_queue_tail(&x->wait, &wait);
3840 do {
Andi Kleen8cbbe862007-10-15 17:00:14 +02003841 if (state == TASK_INTERRUPTIBLE &&
3842 signal_pending(current)) {
3843 __remove_wait_queue(&x->wait, &wait);
3844 return -ERESTARTSYS;
3845 }
3846 __set_current_state(state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003847 spin_unlock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02003848 timeout = schedule_timeout(timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003849 spin_lock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02003850 if (!timeout) {
3851 __remove_wait_queue(&x->wait, &wait);
3852 return timeout;
3853 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07003854 } while (!x->done);
3855 __remove_wait_queue(&x->wait, &wait);
3856 }
3857 x->done--;
Andi Kleen8cbbe862007-10-15 17:00:14 +02003858 return timeout;
3859}
3860
3861static long __sched
3862wait_for_common(struct completion *x, long timeout, int state)
3863{
3864 might_sleep();
3865
3866 spin_lock_irq(&x->wait.lock);
3867 timeout = do_wait_for_common(x, timeout, state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003868 spin_unlock_irq(&x->wait.lock);
Andi Kleen8cbbe862007-10-15 17:00:14 +02003869 return timeout;
3870}
3871
3872void fastcall __sched wait_for_completion(struct completion *x)
3873{
3874 wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003875}
3876EXPORT_SYMBOL(wait_for_completion);
3877
3878unsigned long fastcall __sched
3879wait_for_completion_timeout(struct completion *x, unsigned long timeout)
3880{
Andi Kleen8cbbe862007-10-15 17:00:14 +02003881 return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003882}
3883EXPORT_SYMBOL(wait_for_completion_timeout);
3884
Andi Kleen8cbbe862007-10-15 17:00:14 +02003885int __sched wait_for_completion_interruptible(struct completion *x)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003886{
Andi Kleen51e97992007-10-18 21:32:55 +02003887 long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE);
3888 if (t == -ERESTARTSYS)
3889 return t;
3890 return 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07003891}
3892EXPORT_SYMBOL(wait_for_completion_interruptible);
3893
3894unsigned long fastcall __sched
3895wait_for_completion_interruptible_timeout(struct completion *x,
3896 unsigned long timeout)
3897{
Andi Kleen8cbbe862007-10-15 17:00:14 +02003898 return wait_for_common(x, timeout, TASK_INTERRUPTIBLE);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003899}
3900EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
3901
Andi Kleen8cbbe862007-10-15 17:00:14 +02003902static long __sched
3903sleep_on_common(wait_queue_head_t *q, int state, long timeout)
Ingo Molnar0fec1712007-07-09 18:52:01 +02003904{
3905 unsigned long flags;
3906 wait_queue_t wait;
3907
3908 init_waitqueue_entry(&wait, current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003909
Andi Kleen8cbbe862007-10-15 17:00:14 +02003910 __set_current_state(state);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003911
Andi Kleen8cbbe862007-10-15 17:00:14 +02003912 spin_lock_irqsave(&q->lock, flags);
3913 __add_wait_queue(q, &wait);
3914 spin_unlock(&q->lock);
3915 timeout = schedule_timeout(timeout);
3916 spin_lock_irq(&q->lock);
3917 __remove_wait_queue(q, &wait);
3918 spin_unlock_irqrestore(&q->lock, flags);
3919
3920 return timeout;
3921}
3922
3923void __sched interruptible_sleep_on(wait_queue_head_t *q)
3924{
3925 sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003926}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003927EXPORT_SYMBOL(interruptible_sleep_on);
3928
Ingo Molnar0fec1712007-07-09 18:52:01 +02003929long __sched
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07003930interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003931{
Andi Kleen8cbbe862007-10-15 17:00:14 +02003932 return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003933}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003934EXPORT_SYMBOL(interruptible_sleep_on_timeout);
3935
Ingo Molnar0fec1712007-07-09 18:52:01 +02003936void __sched sleep_on(wait_queue_head_t *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003937{
Andi Kleen8cbbe862007-10-15 17:00:14 +02003938 sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003939}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003940EXPORT_SYMBOL(sleep_on);
3941
Ingo Molnar0fec1712007-07-09 18:52:01 +02003942long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout)
Linus Torvalds1da177e2005-04-16 15:20:36 -07003943{
Andi Kleen8cbbe862007-10-15 17:00:14 +02003944 return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout);
Linus Torvalds1da177e2005-04-16 15:20:36 -07003945}
Linus Torvalds1da177e2005-04-16 15:20:36 -07003946EXPORT_SYMBOL(sleep_on_timeout);
3947
Ingo Molnarb29739f2006-06-27 02:54:51 -07003948#ifdef CONFIG_RT_MUTEXES
3949
3950/*
3951 * rt_mutex_setprio - set the current priority of a task
3952 * @p: task
3953 * @prio: prio value (kernel-internal form)
3954 *
3955 * This function changes the 'effective' priority of a task. It does
3956 * not touch ->normal_prio like __setscheduler().
3957 *
3958 * Used by the rt_mutex code to implement priority inheritance logic.
3959 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07003960void rt_mutex_setprio(struct task_struct *p, int prio)
Ingo Molnarb29739f2006-06-27 02:54:51 -07003961{
3962 unsigned long flags;
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02003963 int oldprio, on_rq, running;
Ingo Molnar70b97a72006-07-03 00:25:42 -07003964 struct rq *rq;
Ingo Molnarb29739f2006-06-27 02:54:51 -07003965
3966 BUG_ON(prio < 0 || prio > MAX_PRIO);
3967
3968 rq = task_rq_lock(p, &flags);
Ingo Molnara8e504d2007-08-09 11:16:47 +02003969 update_rq_clock(rq);
Ingo Molnarb29739f2006-06-27 02:54:51 -07003970
Andrew Mortond5f9f942007-05-08 20:27:06 -07003971 oldprio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02003972 on_rq = p->se.on_rq;
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02003973 running = task_running(rq, p);
3974 if (on_rq) {
Ingo Molnar69be72c2007-08-09 11:16:49 +02003975 dequeue_task(rq, p, 0);
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02003976 if (running)
3977 p->sched_class->put_prev_task(rq, p);
3978 }
Ingo Molnardd41f592007-07-09 18:51:59 +02003979
3980 if (rt_prio(prio))
3981 p->sched_class = &rt_sched_class;
3982 else
3983 p->sched_class = &fair_sched_class;
3984
Ingo Molnarb29739f2006-06-27 02:54:51 -07003985 p->prio = prio;
3986
Ingo Molnardd41f592007-07-09 18:51:59 +02003987 if (on_rq) {
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02003988 if (running)
3989 p->sched_class->set_curr_task(rq);
Ingo Molnar8159f872007-08-09 11:16:49 +02003990 enqueue_task(rq, p, 0);
Ingo Molnarb29739f2006-06-27 02:54:51 -07003991 /*
3992 * Reschedule if we are currently running on this runqueue and
Andrew Mortond5f9f942007-05-08 20:27:06 -07003993 * our priority decreased, or if we are not currently running on
3994 * this runqueue and our priority is higher than the current's
Ingo Molnarb29739f2006-06-27 02:54:51 -07003995 */
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02003996 if (running) {
Andrew Mortond5f9f942007-05-08 20:27:06 -07003997 if (p->prio > oldprio)
3998 resched_task(rq->curr);
Ingo Molnardd41f592007-07-09 18:51:59 +02003999 } else {
4000 check_preempt_curr(rq, p);
4001 }
Ingo Molnarb29739f2006-06-27 02:54:51 -07004002 }
4003 task_rq_unlock(rq, &flags);
4004}
4005
4006#endif
4007
Ingo Molnar36c8b582006-07-03 00:25:41 -07004008void set_user_nice(struct task_struct *p, long nice)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004009{
Ingo Molnardd41f592007-07-09 18:51:59 +02004010 int old_prio, delta, on_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004011 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004012 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004013
4014 if (TASK_NICE(p) == nice || nice < -20 || nice > 19)
4015 return;
4016 /*
4017 * We have to be careful, if called from sys_setpriority(),
4018 * the task might be in the middle of scheduling on another CPU.
4019 */
4020 rq = task_rq_lock(p, &flags);
Ingo Molnara8e504d2007-08-09 11:16:47 +02004021 update_rq_clock(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004022 /*
4023 * The RT priorities are set via sched_setscheduler(), but we still
4024 * allow the 'normal' nice value to be set - but as expected
4025 * it wont have any effect on scheduling until the task is
Ingo Molnardd41f592007-07-09 18:51:59 +02004026 * SCHED_FIFO/SCHED_RR:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004027 */
Ingo Molnare05606d2007-07-09 18:51:59 +02004028 if (task_has_rt_policy(p)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07004029 p->static_prio = NICE_TO_PRIO(nice);
4030 goto out_unlock;
4031 }
Ingo Molnardd41f592007-07-09 18:51:59 +02004032 on_rq = p->se.on_rq;
4033 if (on_rq) {
Ingo Molnar69be72c2007-08-09 11:16:49 +02004034 dequeue_task(rq, p, 0);
Ingo Molnar79b5ddd2007-08-09 11:16:49 +02004035 dec_load(rq, p);
Peter Williams2dd73a42006-06-27 02:54:34 -07004036 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004037
Linus Torvalds1da177e2005-04-16 15:20:36 -07004038 p->static_prio = NICE_TO_PRIO(nice);
Peter Williams2dd73a42006-06-27 02:54:34 -07004039 set_load_weight(p);
Ingo Molnarb29739f2006-06-27 02:54:51 -07004040 old_prio = p->prio;
4041 p->prio = effective_prio(p);
4042 delta = p->prio - old_prio;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004043
Ingo Molnardd41f592007-07-09 18:51:59 +02004044 if (on_rq) {
Ingo Molnar8159f872007-08-09 11:16:49 +02004045 enqueue_task(rq, p, 0);
Ingo Molnar29b4b622007-08-09 11:16:49 +02004046 inc_load(rq, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004047 /*
Andrew Mortond5f9f942007-05-08 20:27:06 -07004048 * If the task increased its priority or is running and
4049 * lowered its priority, then reschedule its CPU:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004050 */
Andrew Mortond5f9f942007-05-08 20:27:06 -07004051 if (delta < 0 || (delta > 0 && task_running(rq, p)))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004052 resched_task(rq->curr);
4053 }
4054out_unlock:
4055 task_rq_unlock(rq, &flags);
4056}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004057EXPORT_SYMBOL(set_user_nice);
4058
Matt Mackalle43379f2005-05-01 08:59:00 -07004059/*
4060 * can_nice - check if a task can reduce its nice value
4061 * @p: task
4062 * @nice: nice value
4063 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004064int can_nice(const struct task_struct *p, const int nice)
Matt Mackalle43379f2005-05-01 08:59:00 -07004065{
Matt Mackall024f4742005-08-18 11:24:19 -07004066 /* convert nice value [19,-20] to rlimit style value [1,40] */
4067 int nice_rlim = 20 - nice;
Ingo Molnar48f24c42006-07-03 00:25:40 -07004068
Matt Mackalle43379f2005-05-01 08:59:00 -07004069 return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur ||
4070 capable(CAP_SYS_NICE));
4071}
4072
Linus Torvalds1da177e2005-04-16 15:20:36 -07004073#ifdef __ARCH_WANT_SYS_NICE
4074
4075/*
4076 * sys_nice - change the priority of the current process.
4077 * @increment: priority increment
4078 *
4079 * sys_setpriority is a more generic, but much slower function that
4080 * does similar things.
4081 */
4082asmlinkage long sys_nice(int increment)
4083{
Ingo Molnar48f24c42006-07-03 00:25:40 -07004084 long nice, retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004085
4086 /*
4087 * Setpriority might change our priority at the same moment.
4088 * We don't have to worry. Conceptually one call occurs first
4089 * and we have a single winner.
4090 */
Matt Mackalle43379f2005-05-01 08:59:00 -07004091 if (increment < -40)
4092 increment = -40;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004093 if (increment > 40)
4094 increment = 40;
4095
4096 nice = PRIO_TO_NICE(current->static_prio) + increment;
4097 if (nice < -20)
4098 nice = -20;
4099 if (nice > 19)
4100 nice = 19;
4101
Matt Mackalle43379f2005-05-01 08:59:00 -07004102 if (increment < 0 && !can_nice(current, nice))
4103 return -EPERM;
4104
Linus Torvalds1da177e2005-04-16 15:20:36 -07004105 retval = security_task_setnice(current, nice);
4106 if (retval)
4107 return retval;
4108
4109 set_user_nice(current, nice);
4110 return 0;
4111}
4112
4113#endif
4114
4115/**
4116 * task_prio - return the priority value of a given task.
4117 * @p: the task in question.
4118 *
4119 * This is the priority value as seen by users in /proc.
4120 * RT tasks are offset by -200. Normal tasks are centered
4121 * around 0, value goes from -16 to +15.
4122 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004123int task_prio(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004124{
4125 return p->prio - MAX_RT_PRIO;
4126}
4127
4128/**
4129 * task_nice - return the nice value of a given task.
4130 * @p: the task in question.
4131 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004132int task_nice(const struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004133{
4134 return TASK_NICE(p);
4135}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004136EXPORT_SYMBOL_GPL(task_nice);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004137
4138/**
4139 * idle_cpu - is a given cpu idle currently?
4140 * @cpu: the processor in question.
4141 */
4142int idle_cpu(int cpu)
4143{
4144 return cpu_curr(cpu) == cpu_rq(cpu)->idle;
4145}
4146
Linus Torvalds1da177e2005-04-16 15:20:36 -07004147/**
4148 * idle_task - return the idle task for a given cpu.
4149 * @cpu: the processor in question.
4150 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004151struct task_struct *idle_task(int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004152{
4153 return cpu_rq(cpu)->idle;
4154}
4155
4156/**
4157 * find_process_by_pid - find a process with a matching PID value.
4158 * @pid: the pid in question.
4159 */
Alexey Dobriyana9957442007-10-15 17:00:13 +02004160static struct task_struct *find_process_by_pid(pid_t pid)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004161{
4162 return pid ? find_task_by_pid(pid) : current;
4163}
4164
4165/* Actually do priority change: must hold rq lock. */
Ingo Molnardd41f592007-07-09 18:51:59 +02004166static void
4167__setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004168{
Ingo Molnardd41f592007-07-09 18:51:59 +02004169 BUG_ON(p->se.on_rq);
Ingo Molnar48f24c42006-07-03 00:25:40 -07004170
Linus Torvalds1da177e2005-04-16 15:20:36 -07004171 p->policy = policy;
Ingo Molnardd41f592007-07-09 18:51:59 +02004172 switch (p->policy) {
4173 case SCHED_NORMAL:
4174 case SCHED_BATCH:
4175 case SCHED_IDLE:
4176 p->sched_class = &fair_sched_class;
4177 break;
4178 case SCHED_FIFO:
4179 case SCHED_RR:
4180 p->sched_class = &rt_sched_class;
4181 break;
4182 }
4183
Linus Torvalds1da177e2005-04-16 15:20:36 -07004184 p->rt_priority = prio;
Ingo Molnarb29739f2006-06-27 02:54:51 -07004185 p->normal_prio = normal_prio(p);
4186 /* we are holding p->pi_lock already */
4187 p->prio = rt_mutex_getprio(p);
Peter Williams2dd73a42006-06-27 02:54:34 -07004188 set_load_weight(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004189}
4190
4191/**
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08004192 * sched_setscheduler - change the scheduling policy and/or RT priority of a thread.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004193 * @p: the task in question.
4194 * @policy: new policy.
4195 * @param: structure containing the new RT priority.
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004196 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08004197 * NOTE that the task may be already dead.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004198 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004199int sched_setscheduler(struct task_struct *p, int policy,
4200 struct sched_param *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004201{
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004202 int retval, oldprio, oldpolicy = -1, on_rq, running;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004203 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004204 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004205
Steven Rostedt66e53932006-06-27 02:54:44 -07004206 /* may grab non-irq protected spin_locks */
4207 BUG_ON(in_interrupt());
Linus Torvalds1da177e2005-04-16 15:20:36 -07004208recheck:
4209 /* double check policy once rq lock held */
4210 if (policy < 0)
4211 policy = oldpolicy = p->policy;
4212 else if (policy != SCHED_FIFO && policy != SCHED_RR &&
Ingo Molnardd41f592007-07-09 18:51:59 +02004213 policy != SCHED_NORMAL && policy != SCHED_BATCH &&
4214 policy != SCHED_IDLE)
Ingo Molnarb0a94992006-01-14 13:20:41 -08004215 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004216 /*
4217 * Valid priorities for SCHED_FIFO and SCHED_RR are
Ingo Molnardd41f592007-07-09 18:51:59 +02004218 * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL,
4219 * SCHED_BATCH and SCHED_IDLE is 0.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004220 */
4221 if (param->sched_priority < 0 ||
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004222 (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) ||
Steven Rostedtd46523e2005-07-25 16:28:39 -04004223 (!p->mm && param->sched_priority > MAX_RT_PRIO-1))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004224 return -EINVAL;
Ingo Molnare05606d2007-07-09 18:51:59 +02004225 if (rt_policy(policy) != (param->sched_priority != 0))
Linus Torvalds1da177e2005-04-16 15:20:36 -07004226 return -EINVAL;
4227
Olivier Croquette37e4ab32005-06-25 14:57:32 -07004228 /*
4229 * Allow unprivileged RT tasks to decrease priority:
4230 */
4231 if (!capable(CAP_SYS_NICE)) {
Ingo Molnare05606d2007-07-09 18:51:59 +02004232 if (rt_policy(policy)) {
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004233 unsigned long rlim_rtprio;
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004234
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004235 if (!lock_task_sighand(p, &flags))
4236 return -ESRCH;
4237 rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur;
4238 unlock_task_sighand(p, &flags);
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004239
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004240 /* can't set/change the rt policy */
4241 if (policy != p->policy && !rlim_rtprio)
4242 return -EPERM;
4243
4244 /* can't increase priority */
4245 if (param->sched_priority > p->rt_priority &&
4246 param->sched_priority > rlim_rtprio)
4247 return -EPERM;
4248 }
Ingo Molnardd41f592007-07-09 18:51:59 +02004249 /*
4250 * Like positive nice levels, dont allow tasks to
4251 * move out of SCHED_IDLE either:
4252 */
4253 if (p->policy == SCHED_IDLE && policy != SCHED_IDLE)
4254 return -EPERM;
Oleg Nesterov8dc3e902006-09-29 02:00:50 -07004255
Olivier Croquette37e4ab32005-06-25 14:57:32 -07004256 /* can't change other user's priorities */
4257 if ((current->euid != p->euid) &&
4258 (current->euid != p->uid))
4259 return -EPERM;
4260 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004261
4262 retval = security_task_setscheduler(p, policy, param);
4263 if (retval)
4264 return retval;
4265 /*
Ingo Molnarb29739f2006-06-27 02:54:51 -07004266 * make sure no PI-waiters arrive (or leave) while we are
4267 * changing the priority of the task:
4268 */
4269 spin_lock_irqsave(&p->pi_lock, flags);
4270 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -07004271 * To be able to change p->policy safely, the apropriate
4272 * runqueue lock must be held.
4273 */
Ingo Molnarb29739f2006-06-27 02:54:51 -07004274 rq = __task_rq_lock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004275 /* recheck policy now with rq lock held */
4276 if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) {
4277 policy = oldpolicy = -1;
Ingo Molnarb29739f2006-06-27 02:54:51 -07004278 __task_rq_unlock(rq);
4279 spin_unlock_irqrestore(&p->pi_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004280 goto recheck;
4281 }
Ingo Molnar2daa3572007-08-09 11:16:51 +02004282 update_rq_clock(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004283 on_rq = p->se.on_rq;
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004284 running = task_running(rq, p);
4285 if (on_rq) {
Ingo Molnar2e1cb742007-08-09 11:16:49 +02004286 deactivate_task(rq, p, 0);
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004287 if (running)
4288 p->sched_class->put_prev_task(rq, p);
4289 }
Dmitry Adamushkof6b53202007-10-15 17:00:08 +02004290
Linus Torvalds1da177e2005-04-16 15:20:36 -07004291 oldprio = p->prio;
Ingo Molnardd41f592007-07-09 18:51:59 +02004292 __setscheduler(rq, p, policy, param->sched_priority);
Dmitry Adamushkof6b53202007-10-15 17:00:08 +02004293
Ingo Molnardd41f592007-07-09 18:51:59 +02004294 if (on_rq) {
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004295 if (running)
4296 p->sched_class->set_curr_task(rq);
Ingo Molnardd41f592007-07-09 18:51:59 +02004297 activate_task(rq, p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004298 /*
4299 * Reschedule if we are currently running on this runqueue and
Andrew Mortond5f9f942007-05-08 20:27:06 -07004300 * our priority decreased, or if we are not currently running on
4301 * this runqueue and our priority is higher than the current's
Linus Torvalds1da177e2005-04-16 15:20:36 -07004302 */
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02004303 if (running) {
Andrew Mortond5f9f942007-05-08 20:27:06 -07004304 if (p->prio > oldprio)
4305 resched_task(rq->curr);
Ingo Molnardd41f592007-07-09 18:51:59 +02004306 } else {
4307 check_preempt_curr(rq, p);
4308 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004309 }
Ingo Molnarb29739f2006-06-27 02:54:51 -07004310 __task_rq_unlock(rq);
4311 spin_unlock_irqrestore(&p->pi_lock, flags);
4312
Thomas Gleixner95e02ca2006-06-27 02:55:02 -07004313 rt_mutex_adjust_pi(p);
4314
Linus Torvalds1da177e2005-04-16 15:20:36 -07004315 return 0;
4316}
4317EXPORT_SYMBOL_GPL(sched_setscheduler);
4318
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004319static int
4320do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004321{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004322 struct sched_param lparam;
4323 struct task_struct *p;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004324 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004325
4326 if (!param || pid < 0)
4327 return -EINVAL;
4328 if (copy_from_user(&lparam, param, sizeof(struct sched_param)))
4329 return -EFAULT;
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004330
4331 rcu_read_lock();
4332 retval = -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004333 p = find_process_by_pid(pid);
Oleg Nesterov5fe1d752006-09-29 02:00:48 -07004334 if (p != NULL)
4335 retval = sched_setscheduler(p, policy, &lparam);
4336 rcu_read_unlock();
Ingo Molnar36c8b582006-07-03 00:25:41 -07004337
Linus Torvalds1da177e2005-04-16 15:20:36 -07004338 return retval;
4339}
4340
4341/**
4342 * sys_sched_setscheduler - set/change the scheduler policy and RT priority
4343 * @pid: the pid in question.
4344 * @policy: new policy.
4345 * @param: structure containing the new RT priority.
4346 */
4347asmlinkage long sys_sched_setscheduler(pid_t pid, int policy,
4348 struct sched_param __user *param)
4349{
Jason Baronc21761f2006-01-18 17:43:03 -08004350 /* negative values for policy are not valid */
4351 if (policy < 0)
4352 return -EINVAL;
4353
Linus Torvalds1da177e2005-04-16 15:20:36 -07004354 return do_sched_setscheduler(pid, policy, param);
4355}
4356
4357/**
4358 * sys_sched_setparam - set/change the RT priority of a thread
4359 * @pid: the pid in question.
4360 * @param: structure containing the new RT priority.
4361 */
4362asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param)
4363{
4364 return do_sched_setscheduler(pid, -1, param);
4365}
4366
4367/**
4368 * sys_sched_getscheduler - get the policy (scheduling class) of a thread
4369 * @pid: the pid in question.
4370 */
4371asmlinkage long sys_sched_getscheduler(pid_t pid)
4372{
Ingo Molnar36c8b582006-07-03 00:25:41 -07004373 struct task_struct *p;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004374 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004375
4376 if (pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02004377 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004378
4379 retval = -ESRCH;
4380 read_lock(&tasklist_lock);
4381 p = find_process_by_pid(pid);
4382 if (p) {
4383 retval = security_task_getscheduler(p);
4384 if (!retval)
4385 retval = p->policy;
4386 }
4387 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004388 return retval;
4389}
4390
4391/**
4392 * sys_sched_getscheduler - get the RT priority of a thread
4393 * @pid: the pid in question.
4394 * @param: structure containing the RT priority.
4395 */
4396asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param)
4397{
4398 struct sched_param lp;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004399 struct task_struct *p;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004400 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004401
4402 if (!param || pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02004403 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004404
4405 read_lock(&tasklist_lock);
4406 p = find_process_by_pid(pid);
4407 retval = -ESRCH;
4408 if (!p)
4409 goto out_unlock;
4410
4411 retval = security_task_getscheduler(p);
4412 if (retval)
4413 goto out_unlock;
4414
4415 lp.sched_priority = p->rt_priority;
4416 read_unlock(&tasklist_lock);
4417
4418 /*
4419 * This one might sleep, we cannot do it with a spinlock held ...
4420 */
4421 retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0;
4422
Linus Torvalds1da177e2005-04-16 15:20:36 -07004423 return retval;
4424
4425out_unlock:
4426 read_unlock(&tasklist_lock);
4427 return retval;
4428}
4429
4430long sched_setaffinity(pid_t pid, cpumask_t new_mask)
4431{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004432 cpumask_t cpus_allowed;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004433 struct task_struct *p;
4434 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004435
Gautham R Shenoy5be93612007-05-09 02:34:04 -07004436 mutex_lock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004437 read_lock(&tasklist_lock);
4438
4439 p = find_process_by_pid(pid);
4440 if (!p) {
4441 read_unlock(&tasklist_lock);
Gautham R Shenoy5be93612007-05-09 02:34:04 -07004442 mutex_unlock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004443 return -ESRCH;
4444 }
4445
4446 /*
4447 * It is not safe to call set_cpus_allowed with the
4448 * tasklist_lock held. We will bump the task_struct's
4449 * usage count and then drop tasklist_lock.
4450 */
4451 get_task_struct(p);
4452 read_unlock(&tasklist_lock);
4453
4454 retval = -EPERM;
4455 if ((current->euid != p->euid) && (current->euid != p->uid) &&
4456 !capable(CAP_SYS_NICE))
4457 goto out_unlock;
4458
David Quigleye7834f82006-06-23 02:03:59 -07004459 retval = security_task_setscheduler(p, 0, NULL);
4460 if (retval)
4461 goto out_unlock;
4462
Linus Torvalds1da177e2005-04-16 15:20:36 -07004463 cpus_allowed = cpuset_cpus_allowed(p);
4464 cpus_and(new_mask, new_mask, cpus_allowed);
4465 retval = set_cpus_allowed(p, new_mask);
4466
4467out_unlock:
4468 put_task_struct(p);
Gautham R Shenoy5be93612007-05-09 02:34:04 -07004469 mutex_unlock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004470 return retval;
4471}
4472
4473static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len,
4474 cpumask_t *new_mask)
4475{
4476 if (len < sizeof(cpumask_t)) {
4477 memset(new_mask, 0, sizeof(cpumask_t));
4478 } else if (len > sizeof(cpumask_t)) {
4479 len = sizeof(cpumask_t);
4480 }
4481 return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0;
4482}
4483
4484/**
4485 * sys_sched_setaffinity - set the cpu affinity of a process
4486 * @pid: pid of the process
4487 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4488 * @user_mask_ptr: user-space pointer to the new cpu mask
4489 */
4490asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len,
4491 unsigned long __user *user_mask_ptr)
4492{
4493 cpumask_t new_mask;
4494 int retval;
4495
4496 retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask);
4497 if (retval)
4498 return retval;
4499
4500 return sched_setaffinity(pid, new_mask);
4501}
4502
4503/*
4504 * Represents all cpu's present in the system
4505 * In systems capable of hotplug, this map could dynamically grow
4506 * as new cpu's are detected in the system via any platform specific
4507 * method, such as ACPI for e.g.
4508 */
4509
Andi Kleen4cef0c62006-01-11 22:44:57 +01004510cpumask_t cpu_present_map __read_mostly;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004511EXPORT_SYMBOL(cpu_present_map);
4512
4513#ifndef CONFIG_SMP
Andi Kleen4cef0c62006-01-11 22:44:57 +01004514cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL;
Greg Bankse16b38f2006-10-02 02:17:40 -07004515EXPORT_SYMBOL(cpu_online_map);
4516
Andi Kleen4cef0c62006-01-11 22:44:57 +01004517cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL;
Greg Bankse16b38f2006-10-02 02:17:40 -07004518EXPORT_SYMBOL(cpu_possible_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004519#endif
4520
4521long sched_getaffinity(pid_t pid, cpumask_t *mask)
4522{
Ingo Molnar36c8b582006-07-03 00:25:41 -07004523 struct task_struct *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004524 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004525
Gautham R Shenoy5be93612007-05-09 02:34:04 -07004526 mutex_lock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004527 read_lock(&tasklist_lock);
4528
4529 retval = -ESRCH;
4530 p = find_process_by_pid(pid);
4531 if (!p)
4532 goto out_unlock;
4533
David Quigleye7834f82006-06-23 02:03:59 -07004534 retval = security_task_getscheduler(p);
4535 if (retval)
4536 goto out_unlock;
4537
Jack Steiner2f7016d2006-02-01 03:05:18 -08004538 cpus_and(*mask, p->cpus_allowed, cpu_online_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004539
4540out_unlock:
4541 read_unlock(&tasklist_lock);
Gautham R Shenoy5be93612007-05-09 02:34:04 -07004542 mutex_unlock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004543
Ulrich Drepper9531b622007-08-09 11:16:46 +02004544 return retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004545}
4546
4547/**
4548 * sys_sched_getaffinity - get the cpu affinity of a process
4549 * @pid: pid of the process
4550 * @len: length in bytes of the bitmask pointed to by user_mask_ptr
4551 * @user_mask_ptr: user-space pointer to hold the current cpu mask
4552 */
4553asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len,
4554 unsigned long __user *user_mask_ptr)
4555{
4556 int ret;
4557 cpumask_t mask;
4558
4559 if (len < sizeof(cpumask_t))
4560 return -EINVAL;
4561
4562 ret = sched_getaffinity(pid, &mask);
4563 if (ret < 0)
4564 return ret;
4565
4566 if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t)))
4567 return -EFAULT;
4568
4569 return sizeof(cpumask_t);
4570}
4571
4572/**
4573 * sys_sched_yield - yield the current processor to other threads.
4574 *
Ingo Molnardd41f592007-07-09 18:51:59 +02004575 * This function yields the current CPU to other tasks. If there are no
4576 * other threads running on this CPU then this function will return.
Linus Torvalds1da177e2005-04-16 15:20:36 -07004577 */
4578asmlinkage long sys_sched_yield(void)
4579{
Ingo Molnar70b97a72006-07-03 00:25:42 -07004580 struct rq *rq = this_rq_lock();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004581
Ingo Molnar2d723762007-10-15 17:00:12 +02004582 schedstat_inc(rq, yld_count);
Dmitry Adamushko4530d7a2007-10-15 17:00:08 +02004583 current->sched_class->yield_task(rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004584
4585 /*
4586 * Since we are going to call schedule() anyway, there's
4587 * no need to preempt or enable interrupts:
4588 */
4589 __release(rq->lock);
Ingo Molnar8a25d5d2006-07-03 00:24:54 -07004590 spin_release(&rq->lock.dep_map, 1, _THIS_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004591 _raw_spin_unlock(&rq->lock);
4592 preempt_enable_no_resched();
4593
4594 schedule();
4595
4596 return 0;
4597}
4598
Andrew Mortone7b38402006-06-30 01:56:00 -07004599static void __cond_resched(void)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004600{
Ingo Molnar8e0a43d2006-06-23 02:05:23 -07004601#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
4602 __might_sleep(__FILE__, __LINE__);
4603#endif
Ingo Molnar5bbcfd92005-07-07 17:57:04 -07004604 /*
4605 * The BKS might be reacquired before we have dropped
4606 * PREEMPT_ACTIVE, which could trigger a second
4607 * cond_resched() call.
4608 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07004609 do {
4610 add_preempt_count(PREEMPT_ACTIVE);
4611 schedule();
4612 sub_preempt_count(PREEMPT_ACTIVE);
4613 } while (need_resched());
4614}
4615
4616int __sched cond_resched(void)
4617{
Ingo Molnar94142322006-12-29 16:48:13 -08004618 if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) &&
4619 system_state == SYSTEM_RUNNING) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07004620 __cond_resched();
4621 return 1;
4622 }
4623 return 0;
4624}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004625EXPORT_SYMBOL(cond_resched);
4626
4627/*
4628 * cond_resched_lock() - if a reschedule is pending, drop the given lock,
4629 * call schedule, and on return reacquire the lock.
4630 *
4631 * This works OK both with and without CONFIG_PREEMPT. We do strange low-level
4632 * operations here to prevent schedule() from being called twice (once via
4633 * spin_unlock(), once by hand).
4634 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07004635int cond_resched_lock(spinlock_t *lock)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004636{
Jan Kara6df3cec2005-06-13 15:52:32 -07004637 int ret = 0;
4638
Linus Torvalds1da177e2005-04-16 15:20:36 -07004639 if (need_lockbreak(lock)) {
4640 spin_unlock(lock);
4641 cpu_relax();
Jan Kara6df3cec2005-06-13 15:52:32 -07004642 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004643 spin_lock(lock);
4644 }
Ingo Molnar94142322006-12-29 16:48:13 -08004645 if (need_resched() && system_state == SYSTEM_RUNNING) {
Ingo Molnar8a25d5d2006-07-03 00:24:54 -07004646 spin_release(&lock->dep_map, 1, _THIS_IP_);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004647 _raw_spin_unlock(lock);
4648 preempt_enable_no_resched();
4649 __cond_resched();
Jan Kara6df3cec2005-06-13 15:52:32 -07004650 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004651 spin_lock(lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004652 }
Jan Kara6df3cec2005-06-13 15:52:32 -07004653 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004654}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004655EXPORT_SYMBOL(cond_resched_lock);
4656
4657int __sched cond_resched_softirq(void)
4658{
4659 BUG_ON(!in_softirq());
4660
Ingo Molnar94142322006-12-29 16:48:13 -08004661 if (need_resched() && system_state == SYSTEM_RUNNING) {
Thomas Gleixner98d82562007-05-23 13:58:18 -07004662 local_bh_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004663 __cond_resched();
4664 local_bh_disable();
4665 return 1;
4666 }
4667 return 0;
4668}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004669EXPORT_SYMBOL(cond_resched_softirq);
4670
Linus Torvalds1da177e2005-04-16 15:20:36 -07004671/**
4672 * yield - yield the current processor to other threads.
4673 *
Robert P. J. Day72fd4a32007-02-10 01:45:59 -08004674 * This is a shortcut for kernel-space yielding - it marks the
Linus Torvalds1da177e2005-04-16 15:20:36 -07004675 * thread runnable and calls sys_sched_yield().
4676 */
4677void __sched yield(void)
4678{
4679 set_current_state(TASK_RUNNING);
4680 sys_sched_yield();
4681}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004682EXPORT_SYMBOL(yield);
4683
4684/*
4685 * This task is about to go to sleep on IO. Increment rq->nr_iowait so
4686 * that process accounting knows that this is a task in IO wait state.
4687 *
4688 * But don't do that if it is a deliberate, throttling IO wait (this task
4689 * has set its backing_dev_info: the queue against which it should throttle)
4690 */
4691void __sched io_schedule(void)
4692{
Ingo Molnar70b97a72006-07-03 00:25:42 -07004693 struct rq *rq = &__raw_get_cpu_var(runqueues);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004694
Shailabh Nagar0ff92242006-07-14 00:24:37 -07004695 delayacct_blkio_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004696 atomic_inc(&rq->nr_iowait);
4697 schedule();
4698 atomic_dec(&rq->nr_iowait);
Shailabh Nagar0ff92242006-07-14 00:24:37 -07004699 delayacct_blkio_end();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004700}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004701EXPORT_SYMBOL(io_schedule);
4702
4703long __sched io_schedule_timeout(long timeout)
4704{
Ingo Molnar70b97a72006-07-03 00:25:42 -07004705 struct rq *rq = &__raw_get_cpu_var(runqueues);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004706 long ret;
4707
Shailabh Nagar0ff92242006-07-14 00:24:37 -07004708 delayacct_blkio_start();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004709 atomic_inc(&rq->nr_iowait);
4710 ret = schedule_timeout(timeout);
4711 atomic_dec(&rq->nr_iowait);
Shailabh Nagar0ff92242006-07-14 00:24:37 -07004712 delayacct_blkio_end();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004713 return ret;
4714}
4715
4716/**
4717 * sys_sched_get_priority_max - return maximum RT priority.
4718 * @policy: scheduling class.
4719 *
4720 * this syscall returns the maximum rt_priority that can be used
4721 * by a given scheduling class.
4722 */
4723asmlinkage long sys_sched_get_priority_max(int policy)
4724{
4725 int ret = -EINVAL;
4726
4727 switch (policy) {
4728 case SCHED_FIFO:
4729 case SCHED_RR:
4730 ret = MAX_USER_RT_PRIO-1;
4731 break;
4732 case SCHED_NORMAL:
Ingo Molnarb0a94992006-01-14 13:20:41 -08004733 case SCHED_BATCH:
Ingo Molnardd41f592007-07-09 18:51:59 +02004734 case SCHED_IDLE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004735 ret = 0;
4736 break;
4737 }
4738 return ret;
4739}
4740
4741/**
4742 * sys_sched_get_priority_min - return minimum RT priority.
4743 * @policy: scheduling class.
4744 *
4745 * this syscall returns the minimum rt_priority that can be used
4746 * by a given scheduling class.
4747 */
4748asmlinkage long sys_sched_get_priority_min(int policy)
4749{
4750 int ret = -EINVAL;
4751
4752 switch (policy) {
4753 case SCHED_FIFO:
4754 case SCHED_RR:
4755 ret = 1;
4756 break;
4757 case SCHED_NORMAL:
Ingo Molnarb0a94992006-01-14 13:20:41 -08004758 case SCHED_BATCH:
Ingo Molnardd41f592007-07-09 18:51:59 +02004759 case SCHED_IDLE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07004760 ret = 0;
4761 }
4762 return ret;
4763}
4764
4765/**
4766 * sys_sched_rr_get_interval - return the default timeslice of a process.
4767 * @pid: pid of the process.
4768 * @interval: userspace pointer to the timeslice value.
4769 *
4770 * this syscall writes the default timeslice value of a given process
4771 * into the user-space timespec buffer. A value of '0' means infinity.
4772 */
4773asmlinkage
4774long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval)
4775{
Ingo Molnar36c8b582006-07-03 00:25:41 -07004776 struct task_struct *p;
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02004777 unsigned int time_slice;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004778 int retval;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004779 struct timespec t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004780
4781 if (pid < 0)
Andi Kleen3a5c3592007-10-15 17:00:14 +02004782 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004783
4784 retval = -ESRCH;
4785 read_lock(&tasklist_lock);
4786 p = find_process_by_pid(pid);
4787 if (!p)
4788 goto out_unlock;
4789
4790 retval = security_task_getscheduler(p);
4791 if (retval)
4792 goto out_unlock;
4793
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02004794 if (p->policy == SCHED_FIFO)
4795 time_slice = 0;
4796 else if (p->policy == SCHED_RR)
4797 time_slice = DEF_TIMESLICE;
4798 else {
4799 struct sched_entity *se = &p->se;
4800 unsigned long flags;
4801 struct rq *rq;
4802
4803 rq = task_rq_lock(p, &flags);
4804 time_slice = NS_TO_JIFFIES(sched_slice(cfs_rq_of(se), se));
4805 task_rq_unlock(rq, &flags);
4806 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07004807 read_unlock(&tasklist_lock);
Dmitry Adamushkoa4ec24b2007-10-15 17:00:13 +02004808 jiffies_to_timespec(time_slice, &t);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004809 retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004810 return retval;
Andi Kleen3a5c3592007-10-15 17:00:14 +02004811
Linus Torvalds1da177e2005-04-16 15:20:36 -07004812out_unlock:
4813 read_unlock(&tasklist_lock);
4814 return retval;
4815}
4816
Andreas Mohr2ed6e342006-07-10 04:43:52 -07004817static const char stat_nam[] = "RSDTtZX";
Ingo Molnar36c8b582006-07-03 00:25:41 -07004818
4819static void show_task(struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004820{
Linus Torvalds1da177e2005-04-16 15:20:36 -07004821 unsigned long free = 0;
Ingo Molnar36c8b582006-07-03 00:25:41 -07004822 unsigned state;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004823
Linus Torvalds1da177e2005-04-16 15:20:36 -07004824 state = p->state ? __ffs(p->state) + 1 : 0;
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004825 printk(KERN_INFO "%-13.13s %c", p->comm,
Andreas Mohr2ed6e342006-07-10 04:43:52 -07004826 state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?');
Ingo Molnar4bd77322007-07-11 21:21:47 +02004827#if BITS_PER_LONG == 32
Linus Torvalds1da177e2005-04-16 15:20:36 -07004828 if (state == TASK_RUNNING)
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004829 printk(KERN_CONT " running ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07004830 else
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004831 printk(KERN_CONT " %08lx ", thread_saved_pc(p));
Linus Torvalds1da177e2005-04-16 15:20:36 -07004832#else
4833 if (state == TASK_RUNNING)
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004834 printk(KERN_CONT " running task ");
Linus Torvalds1da177e2005-04-16 15:20:36 -07004835 else
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004836 printk(KERN_CONT " %016lx ", thread_saved_pc(p));
Linus Torvalds1da177e2005-04-16 15:20:36 -07004837#endif
4838#ifdef CONFIG_DEBUG_STACK_USAGE
4839 {
Al Viro10ebffd2005-11-13 16:06:56 -08004840 unsigned long *n = end_of_stack(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004841 while (!*n)
4842 n++;
Al Viro10ebffd2005-11-13 16:06:56 -08004843 free = (unsigned long)n - (unsigned long)end_of_stack(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004844 }
4845#endif
Ingo Molnarcc4ea792007-10-18 21:32:56 +02004846 printk(KERN_CONT "%5lu %5d %6d\n", free, p->pid, p->parent->pid);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004847
4848 if (state != TASK_RUNNING)
4849 show_stack(p, NULL);
4850}
4851
Ingo Molnare59e2ae2006-12-06 20:35:59 -08004852void show_state_filter(unsigned long state_filter)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004853{
Ingo Molnar36c8b582006-07-03 00:25:41 -07004854 struct task_struct *g, *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004855
Ingo Molnar4bd77322007-07-11 21:21:47 +02004856#if BITS_PER_LONG == 32
4857 printk(KERN_INFO
4858 " task PC stack pid father\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07004859#else
Ingo Molnar4bd77322007-07-11 21:21:47 +02004860 printk(KERN_INFO
4861 " task PC stack pid father\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07004862#endif
4863 read_lock(&tasklist_lock);
4864 do_each_thread(g, p) {
4865 /*
4866 * reset the NMI-timeout, listing all files on a slow
4867 * console might take alot of time:
4868 */
4869 touch_nmi_watchdog();
Ingo Molnar39bc89f2007-04-25 20:50:03 -07004870 if (!state_filter || (p->state & state_filter))
Ingo Molnare59e2ae2006-12-06 20:35:59 -08004871 show_task(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004872 } while_each_thread(g, p);
4873
Jeremy Fitzhardinge04c91672007-05-08 00:28:05 -07004874 touch_all_softlockup_watchdogs();
4875
Ingo Molnardd41f592007-07-09 18:51:59 +02004876#ifdef CONFIG_SCHED_DEBUG
4877 sysrq_sched_debug_show();
4878#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07004879 read_unlock(&tasklist_lock);
Ingo Molnare59e2ae2006-12-06 20:35:59 -08004880 /*
4881 * Only show locks if all tasks are dumped:
4882 */
4883 if (state_filter == -1)
4884 debug_show_all_locks();
Linus Torvalds1da177e2005-04-16 15:20:36 -07004885}
4886
Ingo Molnar1df21052007-07-09 18:51:58 +02004887void __cpuinit init_idle_bootup_task(struct task_struct *idle)
4888{
Ingo Molnardd41f592007-07-09 18:51:59 +02004889 idle->sched_class = &idle_sched_class;
Ingo Molnar1df21052007-07-09 18:51:58 +02004890}
4891
Ingo Molnarf340c0d2005-06-28 16:40:42 +02004892/**
4893 * init_idle - set up an idle thread for a given CPU
4894 * @idle: task in question
4895 * @cpu: cpu the idle task belongs to
4896 *
4897 * NOTE: this function does not set the idle thread's NEED_RESCHED
4898 * flag, to make booting more robust.
4899 */
Nick Piggin5c1e1762006-10-03 01:14:04 -07004900void __cpuinit init_idle(struct task_struct *idle, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004901{
Ingo Molnar70b97a72006-07-03 00:25:42 -07004902 struct rq *rq = cpu_rq(cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004903 unsigned long flags;
4904
Ingo Molnardd41f592007-07-09 18:51:59 +02004905 __sched_fork(idle);
4906 idle->se.exec_start = sched_clock();
4907
Ingo Molnarb29739f2006-06-27 02:54:51 -07004908 idle->prio = idle->normal_prio = MAX_PRIO;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004909 idle->cpus_allowed = cpumask_of_cpu(cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02004910 __set_task_cpu(idle, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004911
4912 spin_lock_irqsave(&rq->lock, flags);
4913 rq->curr = rq->idle = idle;
Nick Piggin4866cde2005-06-25 14:57:23 -07004914#if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW)
4915 idle->oncpu = 1;
4916#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07004917 spin_unlock_irqrestore(&rq->lock, flags);
4918
4919 /* Set the preempt count _outside_ the spinlocks! */
4920#if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL)
Al Viroa1261f52005-11-13 16:06:55 -08004921 task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07004922#else
Al Viroa1261f52005-11-13 16:06:55 -08004923 task_thread_info(idle)->preempt_count = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004924#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02004925 /*
4926 * The idle tasks have their own, simple scheduling class:
4927 */
4928 idle->sched_class = &idle_sched_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004929}
4930
4931/*
4932 * In a system that switches off the HZ timer nohz_cpu_mask
4933 * indicates which cpus entered this state. This is used
4934 * in the rcu update to wait only for active cpus. For system
4935 * which do not switch off the HZ timer nohz_cpu_mask should
4936 * always be CPU_MASK_NONE.
4937 */
4938cpumask_t nohz_cpu_mask = CPU_MASK_NONE;
4939
4940#ifdef CONFIG_SMP
4941/*
4942 * This is how migration works:
4943 *
Ingo Molnar70b97a72006-07-03 00:25:42 -07004944 * 1) we queue a struct migration_req structure in the source CPU's
Linus Torvalds1da177e2005-04-16 15:20:36 -07004945 * runqueue and wake up that CPU's migration thread.
4946 * 2) we down() the locked semaphore => thread blocks.
4947 * 3) migration thread wakes up (implicitly it forces the migrated
4948 * thread off the CPU)
4949 * 4) it gets the migration request and checks whether the migrated
4950 * task is still in the wrong runqueue.
4951 * 5) if it's in the wrong runqueue then the migration thread removes
4952 * it and puts it into the right queue.
4953 * 6) migration thread up()s the semaphore.
4954 * 7) we wake up and the migration is done.
4955 */
4956
4957/*
4958 * Change a given task's CPU affinity. Migrate the thread to a
4959 * proper CPU and schedule it away if the CPU it's executing on
4960 * is removed from the allowed bitmask.
4961 *
4962 * NOTE: the caller must have a valid reference to the task, the
4963 * task must not exit() & deallocate itself prematurely. The
4964 * call is not atomic; no spinlocks may be held.
4965 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07004966int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07004967{
Ingo Molnar70b97a72006-07-03 00:25:42 -07004968 struct migration_req req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004969 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07004970 struct rq *rq;
Ingo Molnar48f24c42006-07-03 00:25:40 -07004971 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07004972
4973 rq = task_rq_lock(p, &flags);
4974 if (!cpus_intersects(new_mask, cpu_online_map)) {
4975 ret = -EINVAL;
4976 goto out;
4977 }
4978
4979 p->cpus_allowed = new_mask;
4980 /* Can the task run on the task's current CPU? If so, we're done */
4981 if (cpu_isset(task_cpu(p), new_mask))
4982 goto out;
4983
4984 if (migrate_task(p, any_online_cpu(new_mask), &req)) {
4985 /* Need help from migration thread: drop lock and wait. */
4986 task_rq_unlock(rq, &flags);
4987 wake_up_process(rq->migration_thread);
4988 wait_for_completion(&req.done);
4989 tlb_migrate_finish(p->mm);
4990 return 0;
4991 }
4992out:
4993 task_rq_unlock(rq, &flags);
Ingo Molnar48f24c42006-07-03 00:25:40 -07004994
Linus Torvalds1da177e2005-04-16 15:20:36 -07004995 return ret;
4996}
Linus Torvalds1da177e2005-04-16 15:20:36 -07004997EXPORT_SYMBOL_GPL(set_cpus_allowed);
4998
4999/*
5000 * Move (not current) task off this cpu, onto dest cpu. We're doing
5001 * this because either it can't run here any more (set_cpus_allowed()
5002 * away from this CPU, or CPU going down), or because we're
5003 * attempting to rebalance this task on exec (sched_exec).
5004 *
5005 * So we race with normal scheduler movements, but that's OK, as long
5006 * as the task is no longer on this CPU.
Kirill Korotaevefc30812006-06-27 02:54:32 -07005007 *
5008 * Returns non-zero if task was successfully migrated.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005009 */
Kirill Korotaevefc30812006-06-27 02:54:32 -07005010static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005011{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005012 struct rq *rq_dest, *rq_src;
Ingo Molnardd41f592007-07-09 18:51:59 +02005013 int ret = 0, on_rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005014
5015 if (unlikely(cpu_is_offline(dest_cpu)))
Kirill Korotaevefc30812006-06-27 02:54:32 -07005016 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005017
5018 rq_src = cpu_rq(src_cpu);
5019 rq_dest = cpu_rq(dest_cpu);
5020
5021 double_rq_lock(rq_src, rq_dest);
5022 /* Already moved. */
5023 if (task_cpu(p) != src_cpu)
5024 goto out;
5025 /* Affinity changed (again). */
5026 if (!cpu_isset(dest_cpu, p->cpus_allowed))
5027 goto out;
5028
Ingo Molnardd41f592007-07-09 18:51:59 +02005029 on_rq = p->se.on_rq;
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02005030 if (on_rq)
Ingo Molnar2e1cb742007-08-09 11:16:49 +02005031 deactivate_task(rq_src, p, 0);
Ingo Molnar6e82a3b2007-08-09 11:16:51 +02005032
Linus Torvalds1da177e2005-04-16 15:20:36 -07005033 set_task_cpu(p, dest_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02005034 if (on_rq) {
5035 activate_task(rq_dest, p, 0);
5036 check_preempt_curr(rq_dest, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005037 }
Kirill Korotaevefc30812006-06-27 02:54:32 -07005038 ret = 1;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005039out:
5040 double_rq_unlock(rq_src, rq_dest);
Kirill Korotaevefc30812006-06-27 02:54:32 -07005041 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005042}
5043
5044/*
5045 * migration_thread - this is a highprio system thread that performs
5046 * thread migration by bumping thread off CPU then 'pushing' onto
5047 * another runqueue.
5048 */
Ingo Molnar95cdf3b2005-09-10 00:26:11 -07005049static int migration_thread(void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005050{
Linus Torvalds1da177e2005-04-16 15:20:36 -07005051 int cpu = (long)data;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005052 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005053
5054 rq = cpu_rq(cpu);
5055 BUG_ON(rq->migration_thread != current);
5056
5057 set_current_state(TASK_INTERRUPTIBLE);
5058 while (!kthread_should_stop()) {
Ingo Molnar70b97a72006-07-03 00:25:42 -07005059 struct migration_req *req;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005060 struct list_head *head;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005061
Linus Torvalds1da177e2005-04-16 15:20:36 -07005062 spin_lock_irq(&rq->lock);
5063
5064 if (cpu_is_offline(cpu)) {
5065 spin_unlock_irq(&rq->lock);
5066 goto wait_to_die;
5067 }
5068
5069 if (rq->active_balance) {
5070 active_load_balance(rq, cpu);
5071 rq->active_balance = 0;
5072 }
5073
5074 head = &rq->migration_queue;
5075
5076 if (list_empty(head)) {
5077 spin_unlock_irq(&rq->lock);
5078 schedule();
5079 set_current_state(TASK_INTERRUPTIBLE);
5080 continue;
5081 }
Ingo Molnar70b97a72006-07-03 00:25:42 -07005082 req = list_entry(head->next, struct migration_req, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005083 list_del_init(head->next);
5084
Nick Piggin674311d2005-06-25 14:57:27 -07005085 spin_unlock(&rq->lock);
5086 __migrate_task(req->task, cpu, req->dest_cpu);
5087 local_irq_enable();
Linus Torvalds1da177e2005-04-16 15:20:36 -07005088
5089 complete(&req->done);
5090 }
5091 __set_current_state(TASK_RUNNING);
5092 return 0;
5093
5094wait_to_die:
5095 /* Wait for kthread_stop */
5096 set_current_state(TASK_INTERRUPTIBLE);
5097 while (!kthread_should_stop()) {
5098 schedule();
5099 set_current_state(TASK_INTERRUPTIBLE);
5100 }
5101 __set_current_state(TASK_RUNNING);
5102 return 0;
5103}
5104
5105#ifdef CONFIG_HOTPLUG_CPU
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005106
5107static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu)
5108{
5109 int ret;
5110
5111 local_irq_disable();
5112 ret = __migrate_task(p, src_cpu, dest_cpu);
5113 local_irq_enable();
5114 return ret;
5115}
5116
Kirill Korotaev054b9102006-12-10 02:20:11 -08005117/*
5118 * Figure out where task on dead CPU should go, use force if neccessary.
5119 * NOTE: interrupts should be disabled by the caller
5120 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005121static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005122{
Kirill Korotaevefc30812006-06-27 02:54:32 -07005123 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005124 cpumask_t mask;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005125 struct rq *rq;
5126 int dest_cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005127
Andi Kleen3a5c3592007-10-15 17:00:14 +02005128 do {
5129 /* On same node? */
5130 mask = node_to_cpumask(cpu_to_node(dead_cpu));
5131 cpus_and(mask, mask, p->cpus_allowed);
5132 dest_cpu = any_online_cpu(mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005133
Andi Kleen3a5c3592007-10-15 17:00:14 +02005134 /* On any allowed CPU? */
5135 if (dest_cpu == NR_CPUS)
5136 dest_cpu = any_online_cpu(p->cpus_allowed);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005137
Andi Kleen3a5c3592007-10-15 17:00:14 +02005138 /* No more Mr. Nice Guy. */
5139 if (dest_cpu == NR_CPUS) {
5140 rq = task_rq_lock(p, &flags);
5141 cpus_setall(p->cpus_allowed);
5142 dest_cpu = any_online_cpu(p->cpus_allowed);
5143 task_rq_unlock(rq, &flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005144
Andi Kleen3a5c3592007-10-15 17:00:14 +02005145 /*
5146 * Don't tell them about moving exiting tasks or
5147 * kernel threads (both mm NULL), since they never
5148 * leave kernel.
5149 */
5150 if (p->mm && printk_ratelimit())
5151 printk(KERN_INFO "process %d (%s) no "
5152 "longer affine to cpu%d\n",
5153 p->pid, p->comm, dead_cpu);
5154 }
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005155 } while (!__migrate_task_irq(p, dead_cpu, dest_cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005156}
5157
5158/*
5159 * While a dead CPU has no uninterruptible tasks queued at this point,
5160 * it might still have a nonzero ->nr_uninterruptible counter, because
5161 * for performance reasons the counter is not stricly tracking tasks to
5162 * their home CPUs. So we just add the counter to another CPU's counter,
5163 * to keep the global sum constant after CPU-down:
5164 */
Ingo Molnar70b97a72006-07-03 00:25:42 -07005165static void migrate_nr_uninterruptible(struct rq *rq_src)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005166{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005167 struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005168 unsigned long flags;
5169
5170 local_irq_save(flags);
5171 double_rq_lock(rq_src, rq_dest);
5172 rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible;
5173 rq_src->nr_uninterruptible = 0;
5174 double_rq_unlock(rq_src, rq_dest);
5175 local_irq_restore(flags);
5176}
5177
5178/* Run through task list and migrate tasks from the dead cpu. */
5179static void migrate_live_tasks(int src_cpu)
5180{
Ingo Molnar48f24c42006-07-03 00:25:40 -07005181 struct task_struct *p, *t;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005182
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005183 read_lock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005184
Ingo Molnar48f24c42006-07-03 00:25:40 -07005185 do_each_thread(t, p) {
5186 if (p == current)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005187 continue;
5188
Ingo Molnar48f24c42006-07-03 00:25:40 -07005189 if (task_cpu(p) == src_cpu)
5190 move_task_off_dead_cpu(src_cpu, p);
5191 } while_each_thread(t, p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005192
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005193 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005194}
5195
Ingo Molnardd41f592007-07-09 18:51:59 +02005196/*
Alexey Dobriyana9957442007-10-15 17:00:13 +02005197 * activate_idle_task - move idle task to the _front_ of runqueue.
5198 */
5199static void activate_idle_task(struct task_struct *p, struct rq *rq)
5200{
5201 update_rq_clock(rq);
5202
5203 if (p->state == TASK_UNINTERRUPTIBLE)
5204 rq->nr_uninterruptible--;
5205
5206 enqueue_task(rq, p, 0);
5207 inc_nr_running(p, rq);
5208}
5209
5210/*
Ingo Molnardd41f592007-07-09 18:51:59 +02005211 * Schedules idle task to be the next runnable task on current CPU.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005212 * It does so by boosting its priority to highest possible and adding it to
Ingo Molnar48f24c42006-07-03 00:25:40 -07005213 * the _front_ of the runqueue. Used by CPU offline code.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005214 */
5215void sched_idle_next(void)
5216{
Ingo Molnar48f24c42006-07-03 00:25:40 -07005217 int this_cpu = smp_processor_id();
Ingo Molnar70b97a72006-07-03 00:25:42 -07005218 struct rq *rq = cpu_rq(this_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005219 struct task_struct *p = rq->idle;
5220 unsigned long flags;
5221
5222 /* cpu has to be offline */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005223 BUG_ON(cpu_online(this_cpu));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005224
Ingo Molnar48f24c42006-07-03 00:25:40 -07005225 /*
5226 * Strictly not necessary since rest of the CPUs are stopped by now
5227 * and interrupts disabled on the current cpu.
Linus Torvalds1da177e2005-04-16 15:20:36 -07005228 */
5229 spin_lock_irqsave(&rq->lock, flags);
5230
Ingo Molnardd41f592007-07-09 18:51:59 +02005231 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005232
5233 /* Add idle task to the _front_ of its priority queue: */
Ingo Molnardd41f592007-07-09 18:51:59 +02005234 activate_idle_task(p, rq);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005235
5236 spin_unlock_irqrestore(&rq->lock, flags);
5237}
5238
Ingo Molnar48f24c42006-07-03 00:25:40 -07005239/*
5240 * Ensures that the idle task is using init_mm right before its cpu goes
Linus Torvalds1da177e2005-04-16 15:20:36 -07005241 * offline.
5242 */
5243void idle_task_exit(void)
5244{
5245 struct mm_struct *mm = current->active_mm;
5246
5247 BUG_ON(cpu_online(smp_processor_id()));
5248
5249 if (mm != &init_mm)
5250 switch_mm(mm, &init_mm, current);
5251 mmdrop(mm);
5252}
5253
Kirill Korotaev054b9102006-12-10 02:20:11 -08005254/* called under rq->lock with disabled interrupts */
Ingo Molnar36c8b582006-07-03 00:25:41 -07005255static void migrate_dead(unsigned int dead_cpu, struct task_struct *p)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005256{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005257 struct rq *rq = cpu_rq(dead_cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005258
5259 /* Must be exiting, otherwise would be on tasklist. */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005260 BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005261
5262 /* Cannot have done final schedule yet: would have vanished. */
Oleg Nesterovc394cc92006-09-29 02:01:11 -07005263 BUG_ON(p->state == TASK_DEAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005264
Ingo Molnar48f24c42006-07-03 00:25:40 -07005265 get_task_struct(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005266
5267 /*
5268 * Drop lock around migration; if someone else moves it,
5269 * that's OK. No task can be added to this CPU, so iteration is
5270 * fine.
5271 */
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005272 spin_unlock_irq(&rq->lock);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005273 move_task_off_dead_cpu(dead_cpu, p);
Oleg Nesterovf7b4cdd2007-10-16 23:30:56 -07005274 spin_lock_irq(&rq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005275
Ingo Molnar48f24c42006-07-03 00:25:40 -07005276 put_task_struct(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005277}
5278
5279/* release_task() removes task from tasklist, so we won't find dead tasks. */
5280static void migrate_dead_tasks(unsigned int dead_cpu)
5281{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005282 struct rq *rq = cpu_rq(dead_cpu);
Ingo Molnardd41f592007-07-09 18:51:59 +02005283 struct task_struct *next;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005284
Ingo Molnardd41f592007-07-09 18:51:59 +02005285 for ( ; ; ) {
5286 if (!rq->nr_running)
5287 break;
Ingo Molnara8e504d2007-08-09 11:16:47 +02005288 update_rq_clock(rq);
Ingo Molnarff95f3d2007-08-09 11:16:49 +02005289 next = pick_next_task(rq, rq->curr);
Ingo Molnardd41f592007-07-09 18:51:59 +02005290 if (!next)
5291 break;
5292 migrate_dead(dead_cpu, next);
Nick Piggine692ab52007-07-26 13:40:43 +02005293
Linus Torvalds1da177e2005-04-16 15:20:36 -07005294 }
5295}
5296#endif /* CONFIG_HOTPLUG_CPU */
5297
Nick Piggine692ab52007-07-26 13:40:43 +02005298#if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL)
5299
5300static struct ctl_table sd_ctl_dir[] = {
Alexey Dobriyane0361852007-08-09 11:16:46 +02005301 {
5302 .procname = "sched_domain",
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005303 .mode = 0555,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005304 },
Nick Piggine692ab52007-07-26 13:40:43 +02005305 {0,},
5306};
5307
5308static struct ctl_table sd_ctl_root[] = {
Alexey Dobriyane0361852007-08-09 11:16:46 +02005309 {
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005310 .ctl_name = CTL_KERN,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005311 .procname = "kernel",
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005312 .mode = 0555,
Alexey Dobriyane0361852007-08-09 11:16:46 +02005313 .child = sd_ctl_dir,
5314 },
Nick Piggine692ab52007-07-26 13:40:43 +02005315 {0,},
5316};
5317
5318static struct ctl_table *sd_alloc_ctl_entry(int n)
5319{
5320 struct ctl_table *entry =
Milton Miller5cf9f062007-10-15 17:00:19 +02005321 kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL);
Nick Piggine692ab52007-07-26 13:40:43 +02005322
Nick Piggine692ab52007-07-26 13:40:43 +02005323 return entry;
5324}
5325
Milton Miller6382bc92007-10-15 17:00:19 +02005326static void sd_free_ctl_entry(struct ctl_table **tablep)
5327{
Milton Millercd790072007-10-17 16:55:11 +02005328 struct ctl_table *entry;
Milton Miller6382bc92007-10-15 17:00:19 +02005329
Milton Millercd790072007-10-17 16:55:11 +02005330 /*
5331 * In the intermediate directories, both the child directory and
5332 * procname are dynamically allocated and could fail but the mode
5333 * will always be set. In the lowest directory the names are
5334 * static strings and all have proc handlers.
5335 */
5336 for (entry = *tablep; entry->mode; entry++) {
Milton Miller6382bc92007-10-15 17:00:19 +02005337 if (entry->child)
5338 sd_free_ctl_entry(&entry->child);
Milton Millercd790072007-10-17 16:55:11 +02005339 if (entry->proc_handler == NULL)
5340 kfree(entry->procname);
5341 }
Milton Miller6382bc92007-10-15 17:00:19 +02005342
5343 kfree(*tablep);
5344 *tablep = NULL;
5345}
5346
Nick Piggine692ab52007-07-26 13:40:43 +02005347static void
Alexey Dobriyane0361852007-08-09 11:16:46 +02005348set_table_entry(struct ctl_table *entry,
Nick Piggine692ab52007-07-26 13:40:43 +02005349 const char *procname, void *data, int maxlen,
5350 mode_t mode, proc_handler *proc_handler)
5351{
Nick Piggine692ab52007-07-26 13:40:43 +02005352 entry->procname = procname;
5353 entry->data = data;
5354 entry->maxlen = maxlen;
5355 entry->mode = mode;
5356 entry->proc_handler = proc_handler;
5357}
5358
5359static struct ctl_table *
5360sd_alloc_ctl_domain_table(struct sched_domain *sd)
5361{
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005362 struct ctl_table *table = sd_alloc_ctl_entry(12);
Nick Piggine692ab52007-07-26 13:40:43 +02005363
Milton Millerad1cdc12007-10-15 17:00:19 +02005364 if (table == NULL)
5365 return NULL;
5366
Alexey Dobriyane0361852007-08-09 11:16:46 +02005367 set_table_entry(&table[0], "min_interval", &sd->min_interval,
Nick Piggine692ab52007-07-26 13:40:43 +02005368 sizeof(long), 0644, proc_doulongvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005369 set_table_entry(&table[1], "max_interval", &sd->max_interval,
Nick Piggine692ab52007-07-26 13:40:43 +02005370 sizeof(long), 0644, proc_doulongvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005371 set_table_entry(&table[2], "busy_idx", &sd->busy_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005372 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005373 set_table_entry(&table[3], "idle_idx", &sd->idle_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005374 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005375 set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005376 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005377 set_table_entry(&table[5], "wake_idx", &sd->wake_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005378 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005379 set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx,
Nick Piggine692ab52007-07-26 13:40:43 +02005380 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005381 set_table_entry(&table[7], "busy_factor", &sd->busy_factor,
Nick Piggine692ab52007-07-26 13:40:43 +02005382 sizeof(int), 0644, proc_dointvec_minmax);
Alexey Dobriyane0361852007-08-09 11:16:46 +02005383 set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct,
Nick Piggine692ab52007-07-26 13:40:43 +02005384 sizeof(int), 0644, proc_dointvec_minmax);
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005385 set_table_entry(&table[9], "cache_nice_tries",
Nick Piggine692ab52007-07-26 13:40:43 +02005386 &sd->cache_nice_tries,
5387 sizeof(int), 0644, proc_dointvec_minmax);
Zou Nan haiace8b3d2007-10-15 17:00:14 +02005388 set_table_entry(&table[10], "flags", &sd->flags,
Nick Piggine692ab52007-07-26 13:40:43 +02005389 sizeof(int), 0644, proc_dointvec_minmax);
Milton Miller6323469f2007-10-15 17:00:19 +02005390 /* &table[11] is terminator */
Nick Piggine692ab52007-07-26 13:40:43 +02005391
5392 return table;
5393}
5394
Ingo Molnar8401f772007-10-18 21:32:55 +02005395static ctl_table * sd_alloc_ctl_cpu_table(int cpu)
Nick Piggine692ab52007-07-26 13:40:43 +02005396{
5397 struct ctl_table *entry, *table;
5398 struct sched_domain *sd;
5399 int domain_num = 0, i;
5400 char buf[32];
5401
5402 for_each_domain(cpu, sd)
5403 domain_num++;
5404 entry = table = sd_alloc_ctl_entry(domain_num + 1);
Milton Millerad1cdc12007-10-15 17:00:19 +02005405 if (table == NULL)
5406 return NULL;
Nick Piggine692ab52007-07-26 13:40:43 +02005407
5408 i = 0;
5409 for_each_domain(cpu, sd) {
5410 snprintf(buf, 32, "domain%d", i);
Nick Piggine692ab52007-07-26 13:40:43 +02005411 entry->procname = kstrdup(buf, GFP_KERNEL);
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005412 entry->mode = 0555;
Nick Piggine692ab52007-07-26 13:40:43 +02005413 entry->child = sd_alloc_ctl_domain_table(sd);
5414 entry++;
5415 i++;
5416 }
5417 return table;
5418}
5419
5420static struct ctl_table_header *sd_sysctl_header;
Milton Miller6382bc92007-10-15 17:00:19 +02005421static void register_sched_domain_sysctl(void)
Nick Piggine692ab52007-07-26 13:40:43 +02005422{
5423 int i, cpu_num = num_online_cpus();
5424 struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1);
5425 char buf[32];
5426
Milton Millerad1cdc12007-10-15 17:00:19 +02005427 if (entry == NULL)
5428 return;
5429
Nick Piggine692ab52007-07-26 13:40:43 +02005430 sd_ctl_dir[0].child = entry;
5431
Milton Miller97b6ea72007-10-15 17:00:19 +02005432 for_each_online_cpu(i) {
Nick Piggine692ab52007-07-26 13:40:43 +02005433 snprintf(buf, 32, "cpu%d", i);
Nick Piggine692ab52007-07-26 13:40:43 +02005434 entry->procname = kstrdup(buf, GFP_KERNEL);
Eric W. Biedermanc57baf12007-08-23 15:18:02 +02005435 entry->mode = 0555;
Nick Piggine692ab52007-07-26 13:40:43 +02005436 entry->child = sd_alloc_ctl_cpu_table(i);
Milton Miller97b6ea72007-10-15 17:00:19 +02005437 entry++;
Nick Piggine692ab52007-07-26 13:40:43 +02005438 }
5439 sd_sysctl_header = register_sysctl_table(sd_ctl_root);
5440}
Milton Miller6382bc92007-10-15 17:00:19 +02005441
5442static void unregister_sched_domain_sysctl(void)
5443{
5444 unregister_sysctl_table(sd_sysctl_header);
5445 sd_sysctl_header = NULL;
5446 sd_free_ctl_entry(&sd_ctl_dir[0].child);
5447}
Nick Piggine692ab52007-07-26 13:40:43 +02005448#else
Milton Miller6382bc92007-10-15 17:00:19 +02005449static void register_sched_domain_sysctl(void)
5450{
5451}
5452static void unregister_sched_domain_sysctl(void)
Nick Piggine692ab52007-07-26 13:40:43 +02005453{
5454}
5455#endif
5456
Linus Torvalds1da177e2005-04-16 15:20:36 -07005457/*
5458 * migration_call - callback that gets triggered when a CPU is added.
5459 * Here we can start up the necessary migration thread for the new CPU.
5460 */
Ingo Molnar48f24c42006-07-03 00:25:40 -07005461static int __cpuinit
5462migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005463{
Linus Torvalds1da177e2005-04-16 15:20:36 -07005464 struct task_struct *p;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005465 int cpu = (long)hcpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005466 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07005467 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005468
5469 switch (action) {
Gautham R Shenoy5be93612007-05-09 02:34:04 -07005470 case CPU_LOCK_ACQUIRE:
5471 mutex_lock(&sched_hotcpu_mutex);
5472 break;
5473
Linus Torvalds1da177e2005-04-16 15:20:36 -07005474 case CPU_UP_PREPARE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07005475 case CPU_UP_PREPARE_FROZEN:
Ingo Molnardd41f592007-07-09 18:51:59 +02005476 p = kthread_create(migration_thread, hcpu, "migration/%d", cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005477 if (IS_ERR(p))
5478 return NOTIFY_BAD;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005479 kthread_bind(p, cpu);
5480 /* Must be high prio: stop_machine expects to yield to it. */
5481 rq = task_rq_lock(p, &flags);
Ingo Molnardd41f592007-07-09 18:51:59 +02005482 __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005483 task_rq_unlock(rq, &flags);
5484 cpu_rq(cpu)->migration_thread = p;
5485 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005486
Linus Torvalds1da177e2005-04-16 15:20:36 -07005487 case CPU_ONLINE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07005488 case CPU_ONLINE_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07005489 /* Strictly unneccessary, as first user will wake it. */
5490 wake_up_process(cpu_rq(cpu)->migration_thread);
5491 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005492
Linus Torvalds1da177e2005-04-16 15:20:36 -07005493#ifdef CONFIG_HOTPLUG_CPU
5494 case CPU_UP_CANCELED:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07005495 case CPU_UP_CANCELED_FROZEN:
Heiko Carstensfc75cdf2006-06-25 05:49:10 -07005496 if (!cpu_rq(cpu)->migration_thread)
5497 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005498 /* Unbind it from offline cpu so it can run. Fall thru. */
Heiko Carstensa4c4af72005-11-07 00:58:38 -08005499 kthread_bind(cpu_rq(cpu)->migration_thread,
5500 any_online_cpu(cpu_online_map));
Linus Torvalds1da177e2005-04-16 15:20:36 -07005501 kthread_stop(cpu_rq(cpu)->migration_thread);
5502 cpu_rq(cpu)->migration_thread = NULL;
5503 break;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005504
Linus Torvalds1da177e2005-04-16 15:20:36 -07005505 case CPU_DEAD:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07005506 case CPU_DEAD_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07005507 migrate_live_tasks(cpu);
5508 rq = cpu_rq(cpu);
5509 kthread_stop(rq->migration_thread);
5510 rq->migration_thread = NULL;
5511 /* Idle task back to normal (off runqueue, low prio) */
Oleg Nesterovd2da2722007-10-16 23:30:56 -07005512 spin_lock_irq(&rq->lock);
Ingo Molnara8e504d2007-08-09 11:16:47 +02005513 update_rq_clock(rq);
Ingo Molnar2e1cb742007-08-09 11:16:49 +02005514 deactivate_task(rq, rq->idle, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005515 rq->idle->static_prio = MAX_PRIO;
Ingo Molnardd41f592007-07-09 18:51:59 +02005516 __setscheduler(rq, rq->idle, SCHED_NORMAL, 0);
5517 rq->idle->sched_class = &idle_sched_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005518 migrate_dead_tasks(cpu);
Oleg Nesterovd2da2722007-10-16 23:30:56 -07005519 spin_unlock_irq(&rq->lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005520 migrate_nr_uninterruptible(rq);
5521 BUG_ON(rq->nr_running != 0);
5522
5523 /* No need to migrate the tasks: it was best-effort if
Gautham R Shenoy5be93612007-05-09 02:34:04 -07005524 * they didn't take sched_hotcpu_mutex. Just wake up
Linus Torvalds1da177e2005-04-16 15:20:36 -07005525 * the requestors. */
5526 spin_lock_irq(&rq->lock);
5527 while (!list_empty(&rq->migration_queue)) {
Ingo Molnar70b97a72006-07-03 00:25:42 -07005528 struct migration_req *req;
5529
Linus Torvalds1da177e2005-04-16 15:20:36 -07005530 req = list_entry(rq->migration_queue.next,
Ingo Molnar70b97a72006-07-03 00:25:42 -07005531 struct migration_req, list);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005532 list_del_init(&req->list);
5533 complete(&req->done);
5534 }
5535 spin_unlock_irq(&rq->lock);
5536 break;
5537#endif
Gautham R Shenoy5be93612007-05-09 02:34:04 -07005538 case CPU_LOCK_RELEASE:
5539 mutex_unlock(&sched_hotcpu_mutex);
5540 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005541 }
5542 return NOTIFY_OK;
5543}
5544
5545/* Register at highest priority so that task migration (migrate_all_tasks)
5546 * happens before everything else.
5547 */
Chandra Seetharaman26c21432006-06-27 02:54:10 -07005548static struct notifier_block __cpuinitdata migration_notifier = {
Linus Torvalds1da177e2005-04-16 15:20:36 -07005549 .notifier_call = migration_call,
5550 .priority = 10
5551};
5552
5553int __init migration_init(void)
5554{
5555 void *cpu = (void *)(long)smp_processor_id();
Akinobu Mita07dccf32006-09-29 02:00:22 -07005556 int err;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005557
5558 /* Start one for the boot CPU: */
Akinobu Mita07dccf32006-09-29 02:00:22 -07005559 err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu);
5560 BUG_ON(err == NOTIFY_BAD);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005561 migration_call(&migration_notifier, CPU_ONLINE, cpu);
5562 register_cpu_notifier(&migration_notifier);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005563
Linus Torvalds1da177e2005-04-16 15:20:36 -07005564 return 0;
5565}
5566#endif
5567
5568#ifdef CONFIG_SMP
Christoph Lameter476f3532007-05-06 14:48:58 -07005569
5570/* Number of possible processor ids */
5571int nr_cpu_ids __read_mostly = NR_CPUS;
5572EXPORT_SYMBOL(nr_cpu_ids);
5573
Ingo Molnar3e9830d2007-10-15 17:00:13 +02005574#ifdef CONFIG_SCHED_DEBUG
Linus Torvalds1da177e2005-04-16 15:20:36 -07005575static void sched_domain_debug(struct sched_domain *sd, int cpu)
5576{
5577 int level = 0;
5578
Nick Piggin41c7ce92005-06-25 14:57:24 -07005579 if (!sd) {
5580 printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu);
5581 return;
5582 }
5583
Linus Torvalds1da177e2005-04-16 15:20:36 -07005584 printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu);
5585
5586 do {
5587 int i;
5588 char str[NR_CPUS];
5589 struct sched_group *group = sd->groups;
5590 cpumask_t groupmask;
5591
5592 cpumask_scnprintf(str, NR_CPUS, sd->span);
5593 cpus_clear(groupmask);
5594
5595 printk(KERN_DEBUG);
5596 for (i = 0; i < level + 1; i++)
5597 printk(" ");
5598 printk("domain %d: ", level);
5599
5600 if (!(sd->flags & SD_LOAD_BALANCE)) {
5601 printk("does not load-balance\n");
5602 if (sd->parent)
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005603 printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain"
5604 " has parent");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005605 break;
5606 }
5607
5608 printk("span %s\n", str);
5609
5610 if (!cpu_isset(cpu, sd->span))
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005611 printk(KERN_ERR "ERROR: domain->span does not contain "
5612 "CPU%d\n", cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005613 if (!cpu_isset(cpu, group->cpumask))
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005614 printk(KERN_ERR "ERROR: domain->groups does not contain"
5615 " CPU%d\n", cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005616
5617 printk(KERN_DEBUG);
5618 for (i = 0; i < level + 2; i++)
5619 printk(" ");
5620 printk("groups:");
5621 do {
5622 if (!group) {
5623 printk("\n");
5624 printk(KERN_ERR "ERROR: group is NULL\n");
5625 break;
5626 }
5627
Eric Dumazet5517d862007-05-08 00:32:57 -07005628 if (!group->__cpu_power) {
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005629 printk(KERN_CONT "\n");
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005630 printk(KERN_ERR "ERROR: domain->cpu_power not "
5631 "set\n");
Ingo Molnar26797a32007-10-15 17:00:13 +02005632 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005633 }
5634
5635 if (!cpus_weight(group->cpumask)) {
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005636 printk(KERN_CONT "\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005637 printk(KERN_ERR "ERROR: empty group\n");
Ingo Molnar26797a32007-10-15 17:00:13 +02005638 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005639 }
5640
5641 if (cpus_intersects(groupmask, group->cpumask)) {
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005642 printk(KERN_CONT "\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005643 printk(KERN_ERR "ERROR: repeated CPUs\n");
Ingo Molnar26797a32007-10-15 17:00:13 +02005644 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005645 }
5646
5647 cpus_or(groupmask, groupmask, group->cpumask);
5648
5649 cpumask_scnprintf(str, NR_CPUS, group->cpumask);
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005650 printk(KERN_CONT " %s", str);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005651
5652 group = group->next;
5653 } while (group != sd->groups);
Ingo Molnarcc4ea792007-10-18 21:32:56 +02005654 printk(KERN_CONT "\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005655
5656 if (!cpus_equal(sd->span, groupmask))
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005657 printk(KERN_ERR "ERROR: groups don't span "
5658 "domain->span\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005659
5660 level++;
5661 sd = sd->parent;
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005662 if (!sd)
5663 continue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005664
Miguel Ojeda Sandonis33859f72006-12-10 02:20:38 -08005665 if (!cpus_subset(groupmask, sd->span))
5666 printk(KERN_ERR "ERROR: parent span is not a superset "
5667 "of domain->span\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -07005668
5669 } while (sd);
5670}
5671#else
Ingo Molnar48f24c42006-07-03 00:25:40 -07005672# define sched_domain_debug(sd, cpu) do { } while (0)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005673#endif
5674
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07005675static int sd_degenerate(struct sched_domain *sd)
Suresh Siddha245af2c2005-06-25 14:57:25 -07005676{
5677 if (cpus_weight(sd->span) == 1)
5678 return 1;
5679
5680 /* Following flags need at least 2 groups */
5681 if (sd->flags & (SD_LOAD_BALANCE |
5682 SD_BALANCE_NEWIDLE |
5683 SD_BALANCE_FORK |
Siddha, Suresh B89c47102006-10-03 01:14:09 -07005684 SD_BALANCE_EXEC |
5685 SD_SHARE_CPUPOWER |
5686 SD_SHARE_PKG_RESOURCES)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07005687 if (sd->groups != sd->groups->next)
5688 return 0;
5689 }
5690
5691 /* Following flags don't use groups */
5692 if (sd->flags & (SD_WAKE_IDLE |
5693 SD_WAKE_AFFINE |
5694 SD_WAKE_BALANCE))
5695 return 0;
5696
5697 return 1;
5698}
5699
Ingo Molnar48f24c42006-07-03 00:25:40 -07005700static int
5701sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent)
Suresh Siddha245af2c2005-06-25 14:57:25 -07005702{
5703 unsigned long cflags = sd->flags, pflags = parent->flags;
5704
5705 if (sd_degenerate(parent))
5706 return 1;
5707
5708 if (!cpus_equal(sd->span, parent->span))
5709 return 0;
5710
5711 /* Does parent contain flags not in child? */
5712 /* WAKE_BALANCE is a subset of WAKE_AFFINE */
5713 if (cflags & SD_WAKE_AFFINE)
5714 pflags &= ~SD_WAKE_BALANCE;
5715 /* Flags needing groups don't count if only 1 group in parent */
5716 if (parent->groups == parent->groups->next) {
5717 pflags &= ~(SD_LOAD_BALANCE |
5718 SD_BALANCE_NEWIDLE |
5719 SD_BALANCE_FORK |
Siddha, Suresh B89c47102006-10-03 01:14:09 -07005720 SD_BALANCE_EXEC |
5721 SD_SHARE_CPUPOWER |
5722 SD_SHARE_PKG_RESOURCES);
Suresh Siddha245af2c2005-06-25 14:57:25 -07005723 }
5724 if (~cflags & pflags)
5725 return 0;
5726
5727 return 1;
5728}
5729
Linus Torvalds1da177e2005-04-16 15:20:36 -07005730/*
5731 * Attach the domain 'sd' to 'cpu' as its base domain. Callers must
5732 * hold the hotplug lock.
5733 */
John Hawkes9c1cfda2005-09-06 15:18:14 -07005734static void cpu_attach_domain(struct sched_domain *sd, int cpu)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005735{
Ingo Molnar70b97a72006-07-03 00:25:42 -07005736 struct rq *rq = cpu_rq(cpu);
Suresh Siddha245af2c2005-06-25 14:57:25 -07005737 struct sched_domain *tmp;
5738
5739 /* Remove the sched domains which do not contribute to scheduling. */
5740 for (tmp = sd; tmp; tmp = tmp->parent) {
5741 struct sched_domain *parent = tmp->parent;
5742 if (!parent)
5743 break;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07005744 if (sd_parent_degenerate(tmp, parent)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07005745 tmp->parent = parent->parent;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07005746 if (parent->parent)
5747 parent->parent->child = tmp;
5748 }
Suresh Siddha245af2c2005-06-25 14:57:25 -07005749 }
5750
Siddha, Suresh B1a848872006-10-03 01:14:08 -07005751 if (sd && sd_degenerate(sd)) {
Suresh Siddha245af2c2005-06-25 14:57:25 -07005752 sd = sd->parent;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07005753 if (sd)
5754 sd->child = NULL;
5755 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07005756
5757 sched_domain_debug(sd, cpu);
5758
Nick Piggin674311d2005-06-25 14:57:27 -07005759 rcu_assign_pointer(rq->sd, sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005760}
5761
5762/* cpus with isolated domains */
Tim Chen67af63a2006-12-22 01:07:50 -08005763static cpumask_t cpu_isolated_map = CPU_MASK_NONE;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005764
5765/* Setup the mask of cpus configured for isolated domains */
5766static int __init isolated_cpu_setup(char *str)
5767{
5768 int ints[NR_CPUS], i;
5769
5770 str = get_options(str, ARRAY_SIZE(ints), ints);
5771 cpus_clear(cpu_isolated_map);
5772 for (i = 1; i <= ints[0]; i++)
5773 if (ints[i] < NR_CPUS)
5774 cpu_set(ints[i], cpu_isolated_map);
5775 return 1;
5776}
5777
Ingo Molnar8927f492007-10-15 17:00:13 +02005778__setup("isolcpus=", isolated_cpu_setup);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005779
5780/*
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005781 * init_sched_build_groups takes the cpumask we wish to span, and a pointer
5782 * to a function which identifies what group(along with sched group) a CPU
5783 * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS
5784 * (due to the fact that we keep track of groups covered with a cpumask_t).
Linus Torvalds1da177e2005-04-16 15:20:36 -07005785 *
5786 * init_sched_build_groups will build a circular linked list of the groups
5787 * covered by the given span, and will set each group's ->cpumask correctly,
5788 * and ->cpu_power to 0.
5789 */
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07005790static void
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005791init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map,
5792 int (*group_fn)(int cpu, const cpumask_t *cpu_map,
5793 struct sched_group **sg))
Linus Torvalds1da177e2005-04-16 15:20:36 -07005794{
5795 struct sched_group *first = NULL, *last = NULL;
5796 cpumask_t covered = CPU_MASK_NONE;
5797 int i;
5798
5799 for_each_cpu_mask(i, span) {
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005800 struct sched_group *sg;
5801 int group = group_fn(i, cpu_map, &sg);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005802 int j;
5803
5804 if (cpu_isset(i, covered))
5805 continue;
5806
5807 sg->cpumask = CPU_MASK_NONE;
Eric Dumazet5517d862007-05-08 00:32:57 -07005808 sg->__cpu_power = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005809
5810 for_each_cpu_mask(j, span) {
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005811 if (group_fn(j, cpu_map, NULL) != group)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005812 continue;
5813
5814 cpu_set(j, covered);
5815 cpu_set(j, sg->cpumask);
5816 }
5817 if (!first)
5818 first = sg;
5819 if (last)
5820 last->next = sg;
5821 last = sg;
5822 }
5823 last->next = first;
5824}
5825
John Hawkes9c1cfda2005-09-06 15:18:14 -07005826#define SD_NODES_PER_DOMAIN 16
Linus Torvalds1da177e2005-04-16 15:20:36 -07005827
John Hawkes9c1cfda2005-09-06 15:18:14 -07005828#ifdef CONFIG_NUMA
akpm@osdl.org198e2f12006-01-12 01:05:30 -08005829
John Hawkes9c1cfda2005-09-06 15:18:14 -07005830/**
5831 * find_next_best_node - find the next node to include in a sched_domain
5832 * @node: node whose sched_domain we're building
5833 * @used_nodes: nodes already in the sched_domain
5834 *
5835 * Find the next node to include in a given scheduling domain. Simply
5836 * finds the closest node not already in the @used_nodes map.
5837 *
5838 * Should use nodemask_t.
5839 */
5840static int find_next_best_node(int node, unsigned long *used_nodes)
5841{
5842 int i, n, val, min_val, best_node = 0;
5843
5844 min_val = INT_MAX;
5845
5846 for (i = 0; i < MAX_NUMNODES; i++) {
5847 /* Start at @node */
5848 n = (node + i) % MAX_NUMNODES;
5849
5850 if (!nr_cpus_node(n))
5851 continue;
5852
5853 /* Skip already used nodes */
5854 if (test_bit(n, used_nodes))
5855 continue;
5856
5857 /* Simple min distance search */
5858 val = node_distance(node, n);
5859
5860 if (val < min_val) {
5861 min_val = val;
5862 best_node = n;
5863 }
5864 }
5865
5866 set_bit(best_node, used_nodes);
5867 return best_node;
5868}
5869
5870/**
5871 * sched_domain_node_span - get a cpumask for a node's sched_domain
5872 * @node: node whose cpumask we're constructing
5873 * @size: number of nodes to include in this span
5874 *
5875 * Given a node, construct a good cpumask for its sched_domain to span. It
5876 * should be one that prevents unnecessary balancing, but also spreads tasks
5877 * out optimally.
5878 */
5879static cpumask_t sched_domain_node_span(int node)
5880{
John Hawkes9c1cfda2005-09-06 15:18:14 -07005881 DECLARE_BITMAP(used_nodes, MAX_NUMNODES);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005882 cpumask_t span, nodemask;
5883 int i;
John Hawkes9c1cfda2005-09-06 15:18:14 -07005884
5885 cpus_clear(span);
5886 bitmap_zero(used_nodes, MAX_NUMNODES);
5887
5888 nodemask = node_to_cpumask(node);
5889 cpus_or(span, span, nodemask);
5890 set_bit(node, used_nodes);
5891
5892 for (i = 1; i < SD_NODES_PER_DOMAIN; i++) {
5893 int next_node = find_next_best_node(node, used_nodes);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005894
John Hawkes9c1cfda2005-09-06 15:18:14 -07005895 nodemask = node_to_cpumask(next_node);
5896 cpus_or(span, span, nodemask);
5897 }
5898
5899 return span;
5900}
5901#endif
5902
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07005903int sched_smt_power_savings = 0, sched_mc_power_savings = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005904
John Hawkes9c1cfda2005-09-06 15:18:14 -07005905/*
Ingo Molnar48f24c42006-07-03 00:25:40 -07005906 * SMT sched-domains:
John Hawkes9c1cfda2005-09-06 15:18:14 -07005907 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07005908#ifdef CONFIG_SCHED_SMT
5909static DEFINE_PER_CPU(struct sched_domain, cpu_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005910static DEFINE_PER_CPU(struct sched_group, sched_group_cpus);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005911
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005912static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map,
5913 struct sched_group **sg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005914{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005915 if (sg)
5916 *sg = &per_cpu(sched_group_cpus, cpu);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005917 return cpu;
5918}
5919#endif
5920
Ingo Molnar48f24c42006-07-03 00:25:40 -07005921/*
5922 * multi-core sched-domains:
5923 */
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005924#ifdef CONFIG_SCHED_MC
5925static DEFINE_PER_CPU(struct sched_domain, core_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005926static DEFINE_PER_CPU(struct sched_group, sched_group_core);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005927#endif
5928
5929#if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT)
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005930static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map,
5931 struct sched_group **sg)
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005932{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005933 int group;
Mike Travisd5a74302007-10-16 01:24:05 -07005934 cpumask_t mask = per_cpu(cpu_sibling_map, cpu);
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07005935 cpus_and(mask, mask, *cpu_map);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005936 group = first_cpu(mask);
5937 if (sg)
5938 *sg = &per_cpu(sched_group_core, group);
5939 return group;
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005940}
5941#elif defined(CONFIG_SCHED_MC)
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005942static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map,
5943 struct sched_group **sg)
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005944{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005945 if (sg)
5946 *sg = &per_cpu(sched_group_core, cpu);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005947 return cpu;
5948}
5949#endif
5950
Linus Torvalds1da177e2005-04-16 15:20:36 -07005951static DEFINE_PER_CPU(struct sched_domain, phys_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005952static DEFINE_PER_CPU(struct sched_group, sched_group_phys);
Ingo Molnar48f24c42006-07-03 00:25:40 -07005953
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005954static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map,
5955 struct sched_group **sg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005956{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005957 int group;
Ingo Molnar48f24c42006-07-03 00:25:40 -07005958#ifdef CONFIG_SCHED_MC
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005959 cpumask_t mask = cpu_coregroup_map(cpu);
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07005960 cpus_and(mask, mask, *cpu_map);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005961 group = first_cpu(mask);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08005962#elif defined(CONFIG_SCHED_SMT)
Mike Travisd5a74302007-10-16 01:24:05 -07005963 cpumask_t mask = per_cpu(cpu_sibling_map, cpu);
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07005964 cpus_and(mask, mask, *cpu_map);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005965 group = first_cpu(mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -07005966#else
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005967 group = cpu;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005968#endif
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005969 if (sg)
5970 *sg = &per_cpu(sched_group_phys, group);
5971 return group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005972}
5973
5974#ifdef CONFIG_NUMA
John Hawkes9c1cfda2005-09-06 15:18:14 -07005975/*
5976 * The init_sched_build_groups can't handle what we want to do with node
5977 * groups, so roll our own. Now each node has its own list of groups which
5978 * gets dynamically allocated.
5979 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07005980static DEFINE_PER_CPU(struct sched_domain, node_domains);
John Hawkesd1b55132005-09-06 15:18:14 -07005981static struct sched_group **sched_group_nodes_bycpu[NR_CPUS];
John Hawkes9c1cfda2005-09-06 15:18:14 -07005982
5983static DEFINE_PER_CPU(struct sched_domain, allnodes_domains);
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005984static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes);
John Hawkes9c1cfda2005-09-06 15:18:14 -07005985
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005986static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map,
5987 struct sched_group **sg)
Linus Torvalds1da177e2005-04-16 15:20:36 -07005988{
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005989 cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu));
5990 int group;
5991
5992 cpus_and(nodemask, nodemask, *cpu_map);
5993 group = first_cpu(nodemask);
5994
5995 if (sg)
5996 *sg = &per_cpu(sched_group_allnodes, group);
5997 return group;
Linus Torvalds1da177e2005-04-16 15:20:36 -07005998}
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08005999
Siddha, Suresh B08069032006-03-27 01:15:23 -08006000static void init_numa_sched_groups_power(struct sched_group *group_head)
6001{
6002 struct sched_group *sg = group_head;
6003 int j;
6004
6005 if (!sg)
6006 return;
Andi Kleen3a5c3592007-10-15 17:00:14 +02006007 do {
6008 for_each_cpu_mask(j, sg->cpumask) {
6009 struct sched_domain *sd;
Siddha, Suresh B08069032006-03-27 01:15:23 -08006010
Andi Kleen3a5c3592007-10-15 17:00:14 +02006011 sd = &per_cpu(phys_domains, j);
6012 if (j != first_cpu(sd->groups->cpumask)) {
6013 /*
6014 * Only add "power" once for each
6015 * physical package.
6016 */
6017 continue;
6018 }
6019
6020 sg_inc_cpu_power(sg, sd->groups->__cpu_power);
Siddha, Suresh B08069032006-03-27 01:15:23 -08006021 }
Andi Kleen3a5c3592007-10-15 17:00:14 +02006022 sg = sg->next;
6023 } while (sg != group_head);
Siddha, Suresh B08069032006-03-27 01:15:23 -08006024}
Linus Torvalds1da177e2005-04-16 15:20:36 -07006025#endif
6026
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006027#ifdef CONFIG_NUMA
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006028/* Free memory allocated for various sched_group structures */
6029static void free_sched_groups(const cpumask_t *cpu_map)
6030{
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006031 int cpu, i;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006032
6033 for_each_cpu_mask(cpu, *cpu_map) {
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006034 struct sched_group **sched_group_nodes
6035 = sched_group_nodes_bycpu[cpu];
6036
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006037 if (!sched_group_nodes)
6038 continue;
6039
6040 for (i = 0; i < MAX_NUMNODES; i++) {
6041 cpumask_t nodemask = node_to_cpumask(i);
6042 struct sched_group *oldsg, *sg = sched_group_nodes[i];
6043
6044 cpus_and(nodemask, nodemask, *cpu_map);
6045 if (cpus_empty(nodemask))
6046 continue;
6047
6048 if (sg == NULL)
6049 continue;
6050 sg = sg->next;
6051next_sg:
6052 oldsg = sg;
6053 sg = sg->next;
6054 kfree(oldsg);
6055 if (oldsg != sched_group_nodes[i])
6056 goto next_sg;
6057 }
6058 kfree(sched_group_nodes);
6059 sched_group_nodes_bycpu[cpu] = NULL;
6060 }
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006061}
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006062#else
6063static void free_sched_groups(const cpumask_t *cpu_map)
6064{
6065}
6066#endif
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006067
Linus Torvalds1da177e2005-04-16 15:20:36 -07006068/*
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006069 * Initialize sched groups cpu_power.
6070 *
6071 * cpu_power indicates the capacity of sched group, which is used while
6072 * distributing the load between different sched groups in a sched domain.
6073 * Typically cpu_power for all the groups in a sched domain will be same unless
6074 * there are asymmetries in the topology. If there are asymmetries, group
6075 * having more cpu_power will pickup more load compared to the group having
6076 * less cpu_power.
6077 *
6078 * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents
6079 * the maximum number of tasks a group can handle in the presence of other idle
6080 * or lightly loaded groups in the same sched domain.
6081 */
6082static void init_sched_groups_power(int cpu, struct sched_domain *sd)
6083{
6084 struct sched_domain *child;
6085 struct sched_group *group;
6086
6087 WARN_ON(!sd || !sd->groups);
6088
6089 if (cpu != first_cpu(sd->groups->cpumask))
6090 return;
6091
6092 child = sd->child;
6093
Eric Dumazet5517d862007-05-08 00:32:57 -07006094 sd->groups->__cpu_power = 0;
6095
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006096 /*
6097 * For perf policy, if the groups in child domain share resources
6098 * (for example cores sharing some portions of the cache hierarchy
6099 * or SMT), then set this domain groups cpu_power such that each group
6100 * can handle only one task, when there are other idle groups in the
6101 * same sched domain.
6102 */
6103 if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) &&
6104 (child->flags &
6105 (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) {
Eric Dumazet5517d862007-05-08 00:32:57 -07006106 sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006107 return;
6108 }
6109
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006110 /*
6111 * add cpu_power of each child group to this groups cpu_power
6112 */
6113 group = child->groups;
6114 do {
Eric Dumazet5517d862007-05-08 00:32:57 -07006115 sg_inc_cpu_power(sd->groups, group->__cpu_power);
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006116 group = group->next;
6117 } while (group != child->groups);
6118}
6119
6120/*
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006121 * Build sched domains for a given set of cpus and attach the sched domains
6122 * to the individual cpus
Linus Torvalds1da177e2005-04-16 15:20:36 -07006123 */
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006124static int build_sched_domains(const cpumask_t *cpu_map)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006125{
6126 int i;
John Hawkesd1b55132005-09-06 15:18:14 -07006127#ifdef CONFIG_NUMA
6128 struct sched_group **sched_group_nodes = NULL;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006129 int sd_allnodes = 0;
John Hawkesd1b55132005-09-06 15:18:14 -07006130
6131 /*
6132 * Allocate the per-node list of sched groups
6133 */
Milton Miller5cf9f062007-10-15 17:00:19 +02006134 sched_group_nodes = kcalloc(MAX_NUMNODES, sizeof(struct sched_group *),
Srivatsa Vaddagirid3a5aa92006-06-27 02:54:39 -07006135 GFP_KERNEL);
John Hawkesd1b55132005-09-06 15:18:14 -07006136 if (!sched_group_nodes) {
6137 printk(KERN_WARNING "Can not alloc sched group node list\n");
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006138 return -ENOMEM;
John Hawkesd1b55132005-09-06 15:18:14 -07006139 }
6140 sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes;
6141#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07006142
6143 /*
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006144 * Set up domains for cpus specified by the cpu_map.
Linus Torvalds1da177e2005-04-16 15:20:36 -07006145 */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006146 for_each_cpu_mask(i, *cpu_map) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07006147 struct sched_domain *sd = NULL, *p;
6148 cpumask_t nodemask = node_to_cpumask(cpu_to_node(i));
6149
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006150 cpus_and(nodemask, nodemask, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006151
6152#ifdef CONFIG_NUMA
Ingo Molnardd41f592007-07-09 18:51:59 +02006153 if (cpus_weight(*cpu_map) >
6154 SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) {
John Hawkes9c1cfda2005-09-06 15:18:14 -07006155 sd = &per_cpu(allnodes_domains, i);
6156 *sd = SD_ALLNODES_INIT;
6157 sd->span = *cpu_map;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006158 cpu_to_allnodes_group(i, cpu_map, &sd->groups);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006159 p = sd;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006160 sd_allnodes = 1;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006161 } else
6162 p = NULL;
6163
Linus Torvalds1da177e2005-04-16 15:20:36 -07006164 sd = &per_cpu(node_domains, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006165 *sd = SD_NODE_INIT;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006166 sd->span = sched_domain_node_span(cpu_to_node(i));
6167 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006168 if (p)
6169 p->child = sd;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006170 cpus_and(sd->span, sd->span, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006171#endif
6172
6173 p = sd;
6174 sd = &per_cpu(phys_domains, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006175 *sd = SD_CPU_INIT;
6176 sd->span = nodemask;
6177 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006178 if (p)
6179 p->child = sd;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006180 cpu_to_phys_group(i, cpu_map, &sd->groups);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006181
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006182#ifdef CONFIG_SCHED_MC
6183 p = sd;
6184 sd = &per_cpu(core_domains, i);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006185 *sd = SD_MC_INIT;
6186 sd->span = cpu_coregroup_map(i);
6187 cpus_and(sd->span, sd->span, *cpu_map);
6188 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006189 p->child = sd;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006190 cpu_to_core_group(i, cpu_map, &sd->groups);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006191#endif
6192
Linus Torvalds1da177e2005-04-16 15:20:36 -07006193#ifdef CONFIG_SCHED_SMT
6194 p = sd;
6195 sd = &per_cpu(cpu_domains, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006196 *sd = SD_SIBLING_INIT;
Mike Travisd5a74302007-10-16 01:24:05 -07006197 sd->span = per_cpu(cpu_sibling_map, i);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006198 cpus_and(sd->span, sd->span, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006199 sd->parent = p;
Siddha, Suresh B1a848872006-10-03 01:14:08 -07006200 p->child = sd;
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006201 cpu_to_cpu_group(i, cpu_map, &sd->groups);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006202#endif
6203 }
6204
6205#ifdef CONFIG_SCHED_SMT
6206 /* Set up CPU (sibling) groups */
John Hawkes9c1cfda2005-09-06 15:18:14 -07006207 for_each_cpu_mask(i, *cpu_map) {
Mike Travisd5a74302007-10-16 01:24:05 -07006208 cpumask_t this_sibling_map = per_cpu(cpu_sibling_map, i);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006209 cpus_and(this_sibling_map, this_sibling_map, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006210 if (i != first_cpu(this_sibling_map))
6211 continue;
6212
Ingo Molnardd41f592007-07-09 18:51:59 +02006213 init_sched_build_groups(this_sibling_map, cpu_map,
6214 &cpu_to_cpu_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006215 }
6216#endif
6217
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006218#ifdef CONFIG_SCHED_MC
6219 /* Set up multi-core groups */
6220 for_each_cpu_mask(i, *cpu_map) {
6221 cpumask_t this_core_map = cpu_coregroup_map(i);
6222 cpus_and(this_core_map, this_core_map, *cpu_map);
6223 if (i != first_cpu(this_core_map))
6224 continue;
Ingo Molnardd41f592007-07-09 18:51:59 +02006225 init_sched_build_groups(this_core_map, cpu_map,
6226 &cpu_to_core_group);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006227 }
6228#endif
6229
Linus Torvalds1da177e2005-04-16 15:20:36 -07006230 /* Set up physical groups */
6231 for (i = 0; i < MAX_NUMNODES; i++) {
6232 cpumask_t nodemask = node_to_cpumask(i);
6233
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006234 cpus_and(nodemask, nodemask, *cpu_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006235 if (cpus_empty(nodemask))
6236 continue;
6237
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006238 init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006239 }
6240
6241#ifdef CONFIG_NUMA
6242 /* Set up node groups */
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006243 if (sd_allnodes)
Ingo Molnardd41f592007-07-09 18:51:59 +02006244 init_sched_build_groups(*cpu_map, cpu_map,
6245 &cpu_to_allnodes_group);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006246
6247 for (i = 0; i < MAX_NUMNODES; i++) {
6248 /* Set up node groups */
6249 struct sched_group *sg, *prev;
6250 cpumask_t nodemask = node_to_cpumask(i);
6251 cpumask_t domainspan;
6252 cpumask_t covered = CPU_MASK_NONE;
6253 int j;
6254
6255 cpus_and(nodemask, nodemask, *cpu_map);
John Hawkesd1b55132005-09-06 15:18:14 -07006256 if (cpus_empty(nodemask)) {
6257 sched_group_nodes[i] = NULL;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006258 continue;
John Hawkesd1b55132005-09-06 15:18:14 -07006259 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07006260
6261 domainspan = sched_domain_node_span(i);
6262 cpus_and(domainspan, domainspan, *cpu_map);
6263
Srivatsa Vaddagiri15f0b672006-06-27 02:54:40 -07006264 sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006265 if (!sg) {
6266 printk(KERN_WARNING "Can not alloc domain group for "
6267 "node %d\n", i);
6268 goto error;
6269 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07006270 sched_group_nodes[i] = sg;
6271 for_each_cpu_mask(j, nodemask) {
6272 struct sched_domain *sd;
Ingo Molnar9761eea2007-07-09 18:52:00 +02006273
John Hawkes9c1cfda2005-09-06 15:18:14 -07006274 sd = &per_cpu(node_domains, j);
6275 sd->groups = sg;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006276 }
Eric Dumazet5517d862007-05-08 00:32:57 -07006277 sg->__cpu_power = 0;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006278 sg->cpumask = nodemask;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006279 sg->next = sg;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006280 cpus_or(covered, covered, nodemask);
6281 prev = sg;
6282
6283 for (j = 0; j < MAX_NUMNODES; j++) {
6284 cpumask_t tmp, notcovered;
6285 int n = (i + j) % MAX_NUMNODES;
6286
6287 cpus_complement(notcovered, covered);
6288 cpus_and(tmp, notcovered, *cpu_map);
6289 cpus_and(tmp, tmp, domainspan);
6290 if (cpus_empty(tmp))
6291 break;
6292
6293 nodemask = node_to_cpumask(n);
6294 cpus_and(tmp, tmp, nodemask);
6295 if (cpus_empty(tmp))
6296 continue;
6297
Srivatsa Vaddagiri15f0b672006-06-27 02:54:40 -07006298 sg = kmalloc_node(sizeof(struct sched_group),
6299 GFP_KERNEL, i);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006300 if (!sg) {
6301 printk(KERN_WARNING
6302 "Can not alloc domain group for node %d\n", j);
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006303 goto error;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006304 }
Eric Dumazet5517d862007-05-08 00:32:57 -07006305 sg->__cpu_power = 0;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006306 sg->cpumask = tmp;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006307 sg->next = prev->next;
John Hawkes9c1cfda2005-09-06 15:18:14 -07006308 cpus_or(covered, covered, tmp);
6309 prev->next = sg;
6310 prev = sg;
6311 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07006312 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07006313#endif
6314
6315 /* Calculate CPU power for physical packages and nodes */
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006316#ifdef CONFIG_SCHED_SMT
6317 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02006318 struct sched_domain *sd = &per_cpu(cpu_domains, i);
6319
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006320 init_sched_groups_power(i, sd);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006321 }
6322#endif
6323#ifdef CONFIG_SCHED_MC
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006324 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02006325 struct sched_domain *sd = &per_cpu(core_domains, i);
6326
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006327 init_sched_groups_power(i, sd);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006328 }
6329#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07006330
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006331 for_each_cpu_mask(i, *cpu_map) {
Ingo Molnardd41f592007-07-09 18:51:59 +02006332 struct sched_domain *sd = &per_cpu(phys_domains, i);
6333
Siddha, Suresh B89c47102006-10-03 01:14:09 -07006334 init_sched_groups_power(i, sd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006335 }
6336
John Hawkes9c1cfda2005-09-06 15:18:14 -07006337#ifdef CONFIG_NUMA
Siddha, Suresh B08069032006-03-27 01:15:23 -08006338 for (i = 0; i < MAX_NUMNODES; i++)
6339 init_numa_sched_groups_power(sched_group_nodes[i]);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006340
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006341 if (sd_allnodes) {
6342 struct sched_group *sg;
Siddha, Suresh Bf712c0c2006-07-30 03:02:59 -07006343
Siddha, Suresh B6711cab2006-12-10 02:20:07 -08006344 cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg);
Siddha, Suresh Bf712c0c2006-07-30 03:02:59 -07006345 init_numa_sched_groups_power(sg);
6346 }
John Hawkes9c1cfda2005-09-06 15:18:14 -07006347#endif
6348
Linus Torvalds1da177e2005-04-16 15:20:36 -07006349 /* Attach the domains */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006350 for_each_cpu_mask(i, *cpu_map) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07006351 struct sched_domain *sd;
6352#ifdef CONFIG_SCHED_SMT
6353 sd = &per_cpu(cpu_domains, i);
Siddha, Suresh B1e9f28f2006-03-27 01:15:22 -08006354#elif defined(CONFIG_SCHED_MC)
6355 sd = &per_cpu(core_domains, i);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006356#else
6357 sd = &per_cpu(phys_domains, i);
6358#endif
6359 cpu_attach_domain(sd, i);
6360 }
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006361
6362 return 0;
6363
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006364#ifdef CONFIG_NUMA
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006365error:
6366 free_sched_groups(cpu_map);
6367 return -ENOMEM;
Siddha, Suresh Ba6160582006-10-03 01:14:06 -07006368#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07006369}
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006370/*
6371 * Set up scheduler domains and groups. Callers must hold the hotplug lock.
6372 */
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006373static int arch_init_sched_domains(const cpumask_t *cpu_map)
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006374{
6375 cpumask_t cpu_default_map;
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006376 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006377
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006378 /*
6379 * Setup mask for cpus without special case scheduling requirements.
6380 * For now this just excludes isolated cpus, but could be used to
6381 * exclude other special cases in the future.
6382 */
6383 cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map);
6384
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006385 err = build_sched_domains(&cpu_default_map);
6386
Milton Miller6382bc92007-10-15 17:00:19 +02006387 register_sched_domain_sysctl();
6388
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006389 return err;
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006390}
6391
6392static void arch_destroy_sched_domains(const cpumask_t *cpu_map)
Linus Torvalds1da177e2005-04-16 15:20:36 -07006393{
Srivatsa Vaddagiri51888ca2006-06-27 02:54:38 -07006394 free_sched_groups(cpu_map);
John Hawkes9c1cfda2005-09-06 15:18:14 -07006395}
Linus Torvalds1da177e2005-04-16 15:20:36 -07006396
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006397/*
6398 * Detach sched domains from a group of cpus specified in cpu_map
6399 * These cpus will now be attached to the NULL domain
6400 */
Arjan van de Ven858119e2006-01-14 13:20:43 -08006401static void detach_destroy_domains(const cpumask_t *cpu_map)
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006402{
6403 int i;
6404
Milton Miller6382bc92007-10-15 17:00:19 +02006405 unregister_sched_domain_sysctl();
6406
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006407 for_each_cpu_mask(i, *cpu_map)
6408 cpu_attach_domain(NULL, i);
6409 synchronize_sched();
6410 arch_destroy_sched_domains(cpu_map);
6411}
6412
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006413#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
Adrian Bunk6707de002007-08-12 18:08:19 +02006414static int arch_reinit_sched_domains(void)
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006415{
6416 int err;
6417
Gautham R Shenoy5be93612007-05-09 02:34:04 -07006418 mutex_lock(&sched_hotcpu_mutex);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006419 detach_destroy_domains(&cpu_online_map);
6420 err = arch_init_sched_domains(&cpu_online_map);
Gautham R Shenoy5be93612007-05-09 02:34:04 -07006421 mutex_unlock(&sched_hotcpu_mutex);
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006422
6423 return err;
6424}
6425
6426static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt)
6427{
6428 int ret;
6429
6430 if (buf[0] != '0' && buf[0] != '1')
6431 return -EINVAL;
6432
6433 if (smt)
6434 sched_smt_power_savings = (buf[0] == '1');
6435 else
6436 sched_mc_power_savings = (buf[0] == '1');
6437
6438 ret = arch_reinit_sched_domains();
6439
6440 return ret ? ret : count;
6441}
6442
Adrian Bunk6707de002007-08-12 18:08:19 +02006443#ifdef CONFIG_SCHED_MC
6444static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page)
6445{
6446 return sprintf(page, "%u\n", sched_mc_power_savings);
6447}
6448static ssize_t sched_mc_power_savings_store(struct sys_device *dev,
6449 const char *buf, size_t count)
6450{
6451 return sched_power_savings_store(buf, count, 0);
6452}
6453static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show,
6454 sched_mc_power_savings_store);
6455#endif
6456
6457#ifdef CONFIG_SCHED_SMT
6458static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page)
6459{
6460 return sprintf(page, "%u\n", sched_smt_power_savings);
6461}
6462static ssize_t sched_smt_power_savings_store(struct sys_device *dev,
6463 const char *buf, size_t count)
6464{
6465 return sched_power_savings_store(buf, count, 1);
6466}
6467static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show,
6468 sched_smt_power_savings_store);
6469#endif
6470
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006471int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls)
6472{
6473 int err = 0;
Ingo Molnar48f24c42006-07-03 00:25:40 -07006474
Siddha, Suresh B5c45bf22006-06-27 02:54:42 -07006475#ifdef CONFIG_SCHED_SMT
6476 if (smt_capable())
6477 err = sysfs_create_file(&cls->kset.kobj,
6478 &attr_sched_smt_power_savings.attr);
6479#endif
6480#ifdef CONFIG_SCHED_MC
6481 if (!err && mc_capable())
6482 err = sysfs_create_file(&cls->kset.kobj,
6483 &attr_sched_mc_power_savings.attr);
6484#endif
6485 return err;
6486}
6487#endif
6488
Linus Torvalds1da177e2005-04-16 15:20:36 -07006489/*
6490 * Force a reinitialization of the sched domains hierarchy. The domains
6491 * and groups cannot be updated in place without racing with the balancing
Nick Piggin41c7ce92005-06-25 14:57:24 -07006492 * code, so we temporarily attach all running cpus to the NULL domain
Linus Torvalds1da177e2005-04-16 15:20:36 -07006493 * which will prevent rebalancing while the sched domains are recalculated.
6494 */
6495static int update_sched_domains(struct notifier_block *nfb,
6496 unsigned long action, void *hcpu)
6497{
Linus Torvalds1da177e2005-04-16 15:20:36 -07006498 switch (action) {
6499 case CPU_UP_PREPARE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006500 case CPU_UP_PREPARE_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07006501 case CPU_DOWN_PREPARE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006502 case CPU_DOWN_PREPARE_FROZEN:
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006503 detach_destroy_domains(&cpu_online_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006504 return NOTIFY_OK;
6505
6506 case CPU_UP_CANCELED:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006507 case CPU_UP_CANCELED_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07006508 case CPU_DOWN_FAILED:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006509 case CPU_DOWN_FAILED_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07006510 case CPU_ONLINE:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006511 case CPU_ONLINE_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07006512 case CPU_DEAD:
Rafael J. Wysocki8bb78442007-05-09 02:35:10 -07006513 case CPU_DEAD_FROZEN:
Linus Torvalds1da177e2005-04-16 15:20:36 -07006514 /*
6515 * Fall through and re-initialise the domains.
6516 */
6517 break;
6518 default:
6519 return NOTIFY_DONE;
6520 }
6521
6522 /* The hotplug lock is already held by cpu_up/cpu_down */
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006523 arch_init_sched_domains(&cpu_online_map);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006524
6525 return NOTIFY_OK;
6526}
Linus Torvalds1da177e2005-04-16 15:20:36 -07006527
6528void __init sched_init_smp(void)
6529{
Nick Piggin5c1e1762006-10-03 01:14:04 -07006530 cpumask_t non_isolated_cpus;
6531
Gautham R Shenoy5be93612007-05-09 02:34:04 -07006532 mutex_lock(&sched_hotcpu_mutex);
Dinakar Guniguntala1a20ff22005-06-25 14:57:33 -07006533 arch_init_sched_domains(&cpu_online_map);
Nathan Lynche5e56732007-01-10 23:15:28 -08006534 cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map);
Nick Piggin5c1e1762006-10-03 01:14:04 -07006535 if (cpus_empty(non_isolated_cpus))
6536 cpu_set(smp_processor_id(), non_isolated_cpus);
Gautham R Shenoy5be93612007-05-09 02:34:04 -07006537 mutex_unlock(&sched_hotcpu_mutex);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006538 /* XXX: Theoretical race here - CPU may be hotplugged now */
6539 hotcpu_notifier(update_sched_domains, 0);
Nick Piggin5c1e1762006-10-03 01:14:04 -07006540
6541 /* Move init over to a non-isolated CPU */
6542 if (set_cpus_allowed(current, non_isolated_cpus) < 0)
6543 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07006544}
6545#else
6546void __init sched_init_smp(void)
6547{
6548}
6549#endif /* CONFIG_SMP */
6550
6551int in_sched_functions(unsigned long addr)
6552{
6553 /* Linker adds these: start and end of __sched functions */
6554 extern char __sched_text_start[], __sched_text_end[];
Ingo Molnar48f24c42006-07-03 00:25:40 -07006555
Linus Torvalds1da177e2005-04-16 15:20:36 -07006556 return in_lock_functions(addr) ||
6557 (addr >= (unsigned long)__sched_text_start
6558 && addr < (unsigned long)__sched_text_end);
6559}
6560
Alexey Dobriyana9957442007-10-15 17:00:13 +02006561static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq)
Ingo Molnardd41f592007-07-09 18:51:59 +02006562{
6563 cfs_rq->tasks_timeline = RB_ROOT;
Ingo Molnardd41f592007-07-09 18:51:59 +02006564#ifdef CONFIG_FAIR_GROUP_SCHED
6565 cfs_rq->rq = rq;
6566#endif
Peter Zijlstra67e9fb22007-10-15 17:00:10 +02006567 cfs_rq->min_vruntime = (u64)(-(1LL << 20));
Ingo Molnardd41f592007-07-09 18:51:59 +02006568}
6569
Linus Torvalds1da177e2005-04-16 15:20:36 -07006570void __init sched_init(void)
6571{
Christoph Lameter476f3532007-05-06 14:48:58 -07006572 int highest_cpu = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02006573 int i, j;
6574
KAMEZAWA Hiroyuki0a945022006-03-28 01:56:37 -08006575 for_each_possible_cpu(i) {
Ingo Molnardd41f592007-07-09 18:51:59 +02006576 struct rt_prio_array *array;
Ingo Molnar70b97a72006-07-03 00:25:42 -07006577 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006578
6579 rq = cpu_rq(i);
6580 spin_lock_init(&rq->lock);
Ingo Molnarfcb99372006-07-03 00:25:10 -07006581 lockdep_set_class(&rq->lock, &rq->rq_lock_key);
Nick Piggin78979862005-06-25 14:57:13 -07006582 rq->nr_running = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02006583 rq->clock = 1;
6584 init_cfs_rq(&rq->cfs, rq);
6585#ifdef CONFIG_FAIR_GROUP_SCHED
6586 INIT_LIST_HEAD(&rq->leaf_cfs_rq_list);
Ingo Molnar3a252012007-10-15 17:00:12 +02006587 {
6588 struct cfs_rq *cfs_rq = &per_cpu(init_cfs_rq, i);
6589 struct sched_entity *se =
6590 &per_cpu(init_sched_entity, i);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006591
Ingo Molnar3a252012007-10-15 17:00:12 +02006592 init_cfs_rq_p[i] = cfs_rq;
6593 init_cfs_rq(cfs_rq, rq);
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006594 cfs_rq->tg = &init_task_group;
Ingo Molnar3a252012007-10-15 17:00:12 +02006595 list_add(&cfs_rq->leaf_cfs_rq_list,
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006596 &rq->leaf_cfs_rq_list);
6597
Ingo Molnar3a252012007-10-15 17:00:12 +02006598 init_sched_entity_p[i] = se;
6599 se->cfs_rq = &rq->cfs;
6600 se->my_q = cfs_rq;
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006601 se->load.weight = init_task_group_load;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006602 se->load.inv_weight =
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006603 div64_64(1ULL<<32, init_task_group_load);
Ingo Molnar3a252012007-10-15 17:00:12 +02006604 se->parent = NULL;
6605 }
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006606 init_task_group.shares = init_task_group_load;
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006607 spin_lock_init(&init_task_group.lock);
Ingo Molnardd41f592007-07-09 18:51:59 +02006608#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -07006609
Ingo Molnardd41f592007-07-09 18:51:59 +02006610 for (j = 0; j < CPU_LOAD_IDX_MAX; j++)
6611 rq->cpu_load[j] = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006612#ifdef CONFIG_SMP
Nick Piggin41c7ce92005-06-25 14:57:24 -07006613 rq->sd = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006614 rq->active_balance = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02006615 rq->next_balance = jiffies;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006616 rq->push_cpu = 0;
Christoph Lameter0a2966b2006-09-25 23:30:51 -07006617 rq->cpu = i;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006618 rq->migration_thread = NULL;
6619 INIT_LIST_HEAD(&rq->migration_queue);
6620#endif
6621 atomic_set(&rq->nr_iowait, 0);
6622
Ingo Molnardd41f592007-07-09 18:51:59 +02006623 array = &rq->rt.active;
6624 for (j = 0; j < MAX_RT_PRIO; j++) {
6625 INIT_LIST_HEAD(array->queue + j);
6626 __clear_bit(j, array->bitmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006627 }
Christoph Lameter476f3532007-05-06 14:48:58 -07006628 highest_cpu = i;
Ingo Molnardd41f592007-07-09 18:51:59 +02006629 /* delimiter for bitsearch: */
6630 __set_bit(MAX_RT_PRIO, array->bitmap);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006631 }
6632
Peter Williams2dd73a42006-06-27 02:54:34 -07006633 set_load_weight(&init_task);
Heiko Carstensb50f60c2006-07-30 03:03:52 -07006634
Avi Kivitye107be32007-07-26 13:40:43 +02006635#ifdef CONFIG_PREEMPT_NOTIFIERS
6636 INIT_HLIST_HEAD(&init_task.preempt_notifiers);
6637#endif
6638
Christoph Lameterc9819f42006-12-10 02:20:25 -08006639#ifdef CONFIG_SMP
Christoph Lameter476f3532007-05-06 14:48:58 -07006640 nr_cpu_ids = highest_cpu + 1;
Christoph Lameterc9819f42006-12-10 02:20:25 -08006641 open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL);
6642#endif
6643
Heiko Carstensb50f60c2006-07-30 03:03:52 -07006644#ifdef CONFIG_RT_MUTEXES
6645 plist_head_init(&init_task.pi_waiters, &init_task.pi_lock);
6646#endif
6647
Linus Torvalds1da177e2005-04-16 15:20:36 -07006648 /*
6649 * The boot idle thread does lazy MMU switching as well:
6650 */
6651 atomic_inc(&init_mm.mm_count);
6652 enter_lazy_tlb(&init_mm, current);
6653
6654 /*
6655 * Make us the idle thread. Technically, schedule() should not be
6656 * called from this thread, however somewhere below it might be,
6657 * but because we are the idle thread, we just pick up running again
6658 * when this runqueue becomes "idle".
6659 */
6660 init_idle(current, smp_processor_id());
Ingo Molnardd41f592007-07-09 18:51:59 +02006661 /*
6662 * During early bootup we pretend to be a normal task:
6663 */
6664 current->sched_class = &fair_sched_class;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006665}
6666
6667#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
6668void __might_sleep(char *file, int line)
6669{
Ingo Molnar48f24c42006-07-03 00:25:40 -07006670#ifdef in_atomic
Linus Torvalds1da177e2005-04-16 15:20:36 -07006671 static unsigned long prev_jiffy; /* ratelimiting */
6672
6673 if ((in_atomic() || irqs_disabled()) &&
6674 system_state == SYSTEM_RUNNING && !oops_in_progress) {
6675 if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
6676 return;
6677 prev_jiffy = jiffies;
Ingo Molnar91368d72006-03-23 03:00:54 -08006678 printk(KERN_ERR "BUG: sleeping function called from invalid"
Linus Torvalds1da177e2005-04-16 15:20:36 -07006679 " context at %s:%d\n", file, line);
6680 printk("in_atomic():%d, irqs_disabled():%d\n",
6681 in_atomic(), irqs_disabled());
Peter Zijlstraa4c410f2006-12-06 20:37:21 -08006682 debug_show_held_locks(current);
Ingo Molnar3117df02006-12-13 00:34:43 -08006683 if (irqs_disabled())
6684 print_irqtrace_events(current);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006685 dump_stack();
6686 }
6687#endif
6688}
6689EXPORT_SYMBOL(__might_sleep);
6690#endif
6691
6692#ifdef CONFIG_MAGIC_SYSRQ
Andi Kleen3a5e4dc2007-10-15 17:00:15 +02006693static void normalize_task(struct rq *rq, struct task_struct *p)
6694{
6695 int on_rq;
6696 update_rq_clock(rq);
6697 on_rq = p->se.on_rq;
6698 if (on_rq)
6699 deactivate_task(rq, p, 0);
6700 __setscheduler(rq, p, SCHED_NORMAL, 0);
6701 if (on_rq) {
6702 activate_task(rq, p, 0);
6703 resched_task(rq->curr);
6704 }
6705}
6706
Linus Torvalds1da177e2005-04-16 15:20:36 -07006707void normalize_rt_tasks(void)
6708{
Ingo Molnara0f98a12007-06-17 18:37:45 +02006709 struct task_struct *g, *p;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006710 unsigned long flags;
Ingo Molnar70b97a72006-07-03 00:25:42 -07006711 struct rq *rq;
Linus Torvalds1da177e2005-04-16 15:20:36 -07006712
6713 read_lock_irq(&tasklist_lock);
Ingo Molnara0f98a12007-06-17 18:37:45 +02006714 do_each_thread(g, p) {
Ingo Molnar178be792007-10-15 17:00:18 +02006715 /*
6716 * Only normalize user tasks:
6717 */
6718 if (!p->mm)
6719 continue;
6720
Ingo Molnardd41f592007-07-09 18:51:59 +02006721 p->se.exec_start = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02006722#ifdef CONFIG_SCHEDSTATS
6723 p->se.wait_start = 0;
6724 p->se.sleep_start = 0;
Ingo Molnardd41f592007-07-09 18:51:59 +02006725 p->se.block_start = 0;
Ingo Molnar6cfb0d52007-08-02 17:41:40 +02006726#endif
Ingo Molnardd41f592007-07-09 18:51:59 +02006727 task_rq(p)->clock = 0;
6728
6729 if (!rt_task(p)) {
6730 /*
6731 * Renice negative nice level userspace
6732 * tasks back to 0:
6733 */
6734 if (TASK_NICE(p) < 0 && p->mm)
6735 set_user_nice(p, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006736 continue;
Ingo Molnardd41f592007-07-09 18:51:59 +02006737 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07006738
Ingo Molnarb29739f2006-06-27 02:54:51 -07006739 spin_lock_irqsave(&p->pi_lock, flags);
6740 rq = __task_rq_lock(p);
Linus Torvalds1da177e2005-04-16 15:20:36 -07006741
Ingo Molnar178be792007-10-15 17:00:18 +02006742 normalize_task(rq, p);
Andi Kleen3a5e4dc2007-10-15 17:00:15 +02006743
Ingo Molnarb29739f2006-06-27 02:54:51 -07006744 __task_rq_unlock(rq);
6745 spin_unlock_irqrestore(&p->pi_lock, flags);
Ingo Molnara0f98a12007-06-17 18:37:45 +02006746 } while_each_thread(g, p);
6747
Linus Torvalds1da177e2005-04-16 15:20:36 -07006748 read_unlock_irq(&tasklist_lock);
6749}
6750
6751#endif /* CONFIG_MAGIC_SYSRQ */
Linus Torvalds1df5c102005-09-12 07:59:21 -07006752
6753#ifdef CONFIG_IA64
6754/*
6755 * These functions are only useful for the IA64 MCA handling.
6756 *
6757 * They can only be called when the whole system has been
6758 * stopped - every CPU needs to be quiescent, and no scheduling
6759 * activity can take place. Using them for anything else would
6760 * be a serious bug, and as a result, they aren't even visible
6761 * under any other configuration.
6762 */
6763
6764/**
6765 * curr_task - return the current task for a given cpu.
6766 * @cpu: the processor in question.
6767 *
6768 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6769 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07006770struct task_struct *curr_task(int cpu)
Linus Torvalds1df5c102005-09-12 07:59:21 -07006771{
6772 return cpu_curr(cpu);
6773}
6774
6775/**
6776 * set_curr_task - set the current task for a given cpu.
6777 * @cpu: the processor in question.
6778 * @p: the task pointer to set.
6779 *
6780 * Description: This function must only be used when non-maskable interrupts
6781 * are serviced on a separate stack. It allows the architecture to switch the
6782 * notion of the current task on a cpu in a non-blocking manner. This function
6783 * must be called with all CPU's synchronized, and interrupts disabled, the
6784 * and caller must save the original value of the current task (see
6785 * curr_task() above) and restore that value before reenabling interrupts and
6786 * re-starting the system.
6787 *
6788 * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED!
6789 */
Ingo Molnar36c8b582006-07-03 00:25:41 -07006790void set_curr_task(int cpu, struct task_struct *p)
Linus Torvalds1df5c102005-09-12 07:59:21 -07006791{
6792 cpu_curr(cpu) = p;
6793}
6794
6795#endif
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006796
6797#ifdef CONFIG_FAIR_GROUP_SCHED
6798
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006799/* allocate runqueue etc for a new task group */
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006800struct task_group *sched_create_group(void)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006801{
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006802 struct task_group *tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006803 struct cfs_rq *cfs_rq;
6804 struct sched_entity *se;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006805 struct rq *rq;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006806 int i;
6807
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006808 tg = kzalloc(sizeof(*tg), GFP_KERNEL);
6809 if (!tg)
6810 return ERR_PTR(-ENOMEM);
6811
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006812 tg->cfs_rq = kzalloc(sizeof(cfs_rq) * NR_CPUS, GFP_KERNEL);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006813 if (!tg->cfs_rq)
6814 goto err;
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006815 tg->se = kzalloc(sizeof(se) * NR_CPUS, GFP_KERNEL);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006816 if (!tg->se)
6817 goto err;
6818
6819 for_each_possible_cpu(i) {
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006820 rq = cpu_rq(i);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006821
6822 cfs_rq = kmalloc_node(sizeof(struct cfs_rq), GFP_KERNEL,
6823 cpu_to_node(i));
6824 if (!cfs_rq)
6825 goto err;
6826
6827 se = kmalloc_node(sizeof(struct sched_entity), GFP_KERNEL,
6828 cpu_to_node(i));
6829 if (!se)
6830 goto err;
6831
6832 memset(cfs_rq, 0, sizeof(struct cfs_rq));
6833 memset(se, 0, sizeof(struct sched_entity));
6834
6835 tg->cfs_rq[i] = cfs_rq;
6836 init_cfs_rq(cfs_rq, rq);
6837 cfs_rq->tg = tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006838
6839 tg->se[i] = se;
6840 se->cfs_rq = &rq->cfs;
6841 se->my_q = cfs_rq;
6842 se->load.weight = NICE_0_LOAD;
6843 se->load.inv_weight = div64_64(1ULL<<32, NICE_0_LOAD);
6844 se->parent = NULL;
6845 }
6846
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006847 for_each_possible_cpu(i) {
6848 rq = cpu_rq(i);
6849 cfs_rq = tg->cfs_rq[i];
6850 list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list);
6851 }
6852
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006853 tg->shares = NICE_0_LOAD;
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006854 spin_lock_init(&tg->lock);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006855
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006856 return tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006857
6858err:
6859 for_each_possible_cpu(i) {
Ingo Molnara65914b2007-10-15 17:00:13 +02006860 if (tg->cfs_rq)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006861 kfree(tg->cfs_rq[i]);
Ingo Molnara65914b2007-10-15 17:00:13 +02006862 if (tg->se)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006863 kfree(tg->se[i]);
6864 }
Ingo Molnara65914b2007-10-15 17:00:13 +02006865 kfree(tg->cfs_rq);
6866 kfree(tg->se);
6867 kfree(tg);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006868
6869 return ERR_PTR(-ENOMEM);
6870}
6871
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006872/* rcu callback to free various structures associated with a task group */
6873static void free_sched_group(struct rcu_head *rhp)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006874{
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006875 struct cfs_rq *cfs_rq = container_of(rhp, struct cfs_rq, rcu);
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006876 struct task_group *tg = cfs_rq->tg;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006877 struct sched_entity *se;
6878 int i;
6879
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006880 /* now it should be safe to free those cfs_rqs */
6881 for_each_possible_cpu(i) {
6882 cfs_rq = tg->cfs_rq[i];
6883 kfree(cfs_rq);
6884
6885 se = tg->se[i];
6886 kfree(se);
6887 }
6888
6889 kfree(tg->cfs_rq);
6890 kfree(tg->se);
6891 kfree(tg);
6892}
6893
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006894/* Destroy runqueue etc associated with a task group */
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006895void sched_destroy_group(struct task_group *tg)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006896{
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006897 struct cfs_rq *cfs_rq;
6898 int i;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006899
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006900 for_each_possible_cpu(i) {
6901 cfs_rq = tg->cfs_rq[i];
6902 list_del_rcu(&cfs_rq->leaf_cfs_rq_list);
6903 }
6904
6905 cfs_rq = tg->cfs_rq[0];
6906
6907 /* wait for possible concurrent references to cfs_rqs complete */
6908 call_rcu(&cfs_rq->rcu, free_sched_group);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006909}
6910
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006911/* change task's runqueue when it moves between groups.
Ingo Molnar3a252012007-10-15 17:00:12 +02006912 * The caller of this function should have put the task in its new group
6913 * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to
6914 * reflect its new group.
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006915 */
6916void sched_move_task(struct task_struct *tsk)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006917{
6918 int on_rq, running;
6919 unsigned long flags;
6920 struct rq *rq;
6921
6922 rq = task_rq_lock(tsk, &flags);
6923
6924 if (tsk->sched_class != &fair_sched_class)
6925 goto done;
6926
6927 update_rq_clock(rq);
6928
6929 running = task_running(rq, tsk);
6930 on_rq = tsk->se.on_rq;
6931
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02006932 if (on_rq) {
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006933 dequeue_task(rq, tsk, 0);
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02006934 if (unlikely(running))
6935 tsk->sched_class->put_prev_task(rq, tsk);
6936 }
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006937
6938 set_task_cfs_rq(tsk);
6939
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02006940 if (on_rq) {
6941 if (unlikely(running))
6942 tsk->sched_class->set_curr_task(rq);
Dmitry Adamushko7074bad2007-10-15 17:00:07 +02006943 enqueue_task(rq, tsk, 0);
Srivatsa Vaddagiri83b699e2007-10-15 17:00:08 +02006944 }
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006945
6946done:
6947 task_rq_unlock(rq, &flags);
6948}
6949
6950static void set_se_shares(struct sched_entity *se, unsigned long shares)
6951{
6952 struct cfs_rq *cfs_rq = se->cfs_rq;
6953 struct rq *rq = cfs_rq->rq;
6954 int on_rq;
6955
6956 spin_lock_irq(&rq->lock);
6957
6958 on_rq = se->on_rq;
6959 if (on_rq)
6960 dequeue_entity(cfs_rq, se, 0);
6961
6962 se->load.weight = shares;
6963 se->load.inv_weight = div64_64((1ULL<<32), shares);
6964
6965 if (on_rq)
6966 enqueue_entity(cfs_rq, se, 0);
6967
6968 spin_unlock_irq(&rq->lock);
6969}
6970
Ingo Molnar4cf86d72007-10-15 17:00:14 +02006971int sched_group_set_shares(struct task_group *tg, unsigned long shares)
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006972{
6973 int i;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006974
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006975 spin_lock(&tg->lock);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006976 if (tg->shares == shares)
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006977 goto done;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006978
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006979 tg->shares = shares;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006980 for_each_possible_cpu(i)
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006981 set_se_shares(tg->se[i], shares);
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006982
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006983done:
6984 spin_unlock(&tg->lock);
Srivatsa Vaddagiri9b5b7752007-10-15 17:00:09 +02006985 return 0;
Srivatsa Vaddagiri29f59db2007-10-15 17:00:07 +02006986}
6987
Dhaval Giani5cb350b2007-10-15 17:00:14 +02006988unsigned long sched_group_shares(struct task_group *tg)
6989{
6990 return tg->shares;
6991}
6992
Ingo Molnar3a252012007-10-15 17:00:12 +02006993#endif /* CONFIG_FAIR_GROUP_SCHED */