Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 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 |
| 19 | */ |
| 20 | |
| 21 | #include <linux/mm.h> |
| 22 | #include <linux/module.h> |
| 23 | #include <linux/nmi.h> |
| 24 | #include <linux/init.h> |
| 25 | #include <asm/uaccess.h> |
| 26 | #include <linux/highmem.h> |
| 27 | #include <linux/smp_lock.h> |
| 28 | #include <asm/mmu_context.h> |
| 29 | #include <linux/interrupt.h> |
Randy.Dunlap | c59ede7 | 2006-01-11 12:17:46 -0800 | [diff] [blame] | 30 | #include <linux/capability.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 31 | #include <linux/completion.h> |
| 32 | #include <linux/kernel_stat.h> |
Ingo Molnar | 9a11b49a | 2006-07-03 00:24:33 -0700 | [diff] [blame] | 33 | #include <linux/debug_locks.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 34 | #include <linux/security.h> |
| 35 | #include <linux/notifier.h> |
| 36 | #include <linux/profile.h> |
Nigel Cunningham | 7dfb710 | 2006-12-06 20:34:23 -0800 | [diff] [blame] | 37 | #include <linux/freezer.h> |
akpm@osdl.org | 198e2f1 | 2006-01-12 01:05:30 -0800 | [diff] [blame] | 38 | #include <linux/vmalloc.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 39 | #include <linux/blkdev.h> |
| 40 | #include <linux/delay.h> |
| 41 | #include <linux/smp.h> |
| 42 | #include <linux/threads.h> |
| 43 | #include <linux/timer.h> |
| 44 | #include <linux/rcupdate.h> |
| 45 | #include <linux/cpu.h> |
| 46 | #include <linux/cpuset.h> |
| 47 | #include <linux/percpu.h> |
| 48 | #include <linux/kthread.h> |
| 49 | #include <linux/seq_file.h> |
| 50 | #include <linux/syscalls.h> |
| 51 | #include <linux/times.h> |
Jay Lan | 8f0ab51 | 2006-09-30 23:28:59 -0700 | [diff] [blame] | 52 | #include <linux/tsacct_kern.h> |
bibo mao | c6fd91f | 2006-03-26 01:38:20 -0800 | [diff] [blame] | 53 | #include <linux/kprobes.h> |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 54 | #include <linux/delayacct.h> |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 55 | #include <linux/reciprocal_div.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 56 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 57 | #include <asm/tlb.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | #include <asm/unistd.h> |
| 59 | |
| 60 | /* |
Alexey Dobriyan | b035b6d | 2007-02-10 01:45:10 -0800 | [diff] [blame] | 61 | * Scheduler clock - returns current time in nanosec units. |
| 62 | * This is default implementation. |
| 63 | * Architectures and sub-architectures can override this. |
| 64 | */ |
| 65 | unsigned long long __attribute__((weak)) sched_clock(void) |
| 66 | { |
| 67 | return (unsigned long long)jiffies * (1000000000 / HZ); |
| 68 | } |
| 69 | |
| 70 | /* |
Ingo Molnar | bb29ab2 | 2007-07-09 18:51:59 +0200 | [diff] [blame^] | 71 | * CPU frequency is/was unstable - start new by setting prev_clock_raw: |
| 72 | */ |
| 73 | void sched_clock_unstable_event(void) |
| 74 | { |
| 75 | } |
| 76 | |
| 77 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 78 | * Convert user-nice values [ -20 ... 0 ... 19 ] |
| 79 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], |
| 80 | * and back. |
| 81 | */ |
| 82 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) |
| 83 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) |
| 84 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) |
| 85 | |
| 86 | /* |
| 87 | * 'User priority' is the nice value converted to something we |
| 88 | * can work with better when scaling various scheduler parameters, |
| 89 | * it's a [ 0 ... 39 ] range. |
| 90 | */ |
| 91 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) |
| 92 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) |
| 93 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) |
| 94 | |
| 95 | /* |
| 96 | * Some helpers for converting nanosecond timing to jiffy resolution |
| 97 | */ |
| 98 | #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) |
| 99 | #define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) |
| 100 | |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 101 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
| 102 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT |
| 103 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | /* |
| 105 | * These are the 'tuning knobs' of the scheduler: |
| 106 | * |
| 107 | * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), |
| 108 | * default timeslice is 100 msecs, maximum timeslice is 800 msecs. |
| 109 | * Timeslices get refilled after they expire. |
| 110 | */ |
| 111 | #define MIN_TIMESLICE max(5 * HZ / 1000, 1) |
| 112 | #define DEF_TIMESLICE (100 * HZ / 1000) |
| 113 | #define ON_RUNQUEUE_WEIGHT 30 |
| 114 | #define CHILD_PENALTY 95 |
| 115 | #define PARENT_PENALTY 100 |
| 116 | #define EXIT_WEIGHT 3 |
| 117 | #define PRIO_BONUS_RATIO 25 |
| 118 | #define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) |
| 119 | #define INTERACTIVE_DELTA 2 |
| 120 | #define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS) |
| 121 | #define STARVATION_LIMIT (MAX_SLEEP_AVG) |
| 122 | #define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) |
| 123 | |
| 124 | /* |
| 125 | * If a task is 'interactive' then we reinsert it in the active |
| 126 | * array after it has expired its current timeslice. (it will not |
| 127 | * continue to run immediately, it will still roundrobin with |
| 128 | * other interactive tasks.) |
| 129 | * |
| 130 | * This part scales the interactivity limit depending on niceness. |
| 131 | * |
| 132 | * We scale it linearly, offset by the INTERACTIVE_DELTA delta. |
| 133 | * Here are a few examples of different nice levels: |
| 134 | * |
| 135 | * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0] |
| 136 | * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0] |
| 137 | * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0] |
| 138 | * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0] |
| 139 | * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0] |
| 140 | * |
| 141 | * (the X axis represents the possible -5 ... 0 ... +5 dynamic |
| 142 | * priority range a task can explore, a value of '1' means the |
| 143 | * task is rated interactive.) |
| 144 | * |
| 145 | * Ie. nice +19 tasks can never get 'interactive' enough to be |
| 146 | * reinserted into the active array. And only heavily CPU-hog nice -20 |
| 147 | * tasks will be expired. Default nice 0 tasks are somewhere between, |
| 148 | * it takes some effort for them to get interactive, but it's not |
| 149 | * too hard. |
| 150 | */ |
| 151 | |
| 152 | #define CURRENT_BONUS(p) \ |
| 153 | (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ |
| 154 | MAX_SLEEP_AVG) |
| 155 | |
| 156 | #define GRANULARITY (10 * HZ / 1000 ? : 1) |
| 157 | |
| 158 | #ifdef CONFIG_SMP |
| 159 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ |
| 160 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ |
| 161 | num_online_cpus()) |
| 162 | #else |
| 163 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ |
| 164 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) |
| 165 | #endif |
| 166 | |
| 167 | #define SCALE(v1,v1_max,v2_max) \ |
| 168 | (v1) * (v2_max) / (v1_max) |
| 169 | |
| 170 | #define DELTA(p) \ |
Martin Andersson | 013d386 | 2006-03-27 01:15:18 -0800 | [diff] [blame] | 171 | (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \ |
| 172 | INTERACTIVE_DELTA) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 173 | |
| 174 | #define TASK_INTERACTIVE(p) \ |
| 175 | ((p)->prio <= (p)->static_prio - DELTA(p)) |
| 176 | |
| 177 | #define INTERACTIVE_SLEEP(p) \ |
| 178 | (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ |
| 179 | (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) |
| 180 | |
| 181 | #define TASK_PREEMPTS_CURR(p, rq) \ |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 182 | ((p)->prio < (rq)->curr->prio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 183 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 184 | #define SCALE_PRIO(x, prio) \ |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 185 | max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 186 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 187 | static unsigned int static_prio_timeslice(int static_prio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 188 | { |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 189 | if (static_prio < NICE_TO_PRIO(0)) |
| 190 | return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 191 | else |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 192 | return SCALE_PRIO(DEF_TIMESLICE, static_prio); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 193 | } |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 194 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 195 | #ifdef CONFIG_SMP |
| 196 | /* |
| 197 | * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) |
| 198 | * Since cpu_power is a 'constant', we can use a reciprocal divide. |
| 199 | */ |
| 200 | static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) |
| 201 | { |
| 202 | return reciprocal_divide(load, sg->reciprocal_cpu_power); |
| 203 | } |
| 204 | |
| 205 | /* |
| 206 | * Each time a sched group cpu_power is changed, |
| 207 | * we must compute its reciprocal value |
| 208 | */ |
| 209 | static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) |
| 210 | { |
| 211 | sg->__cpu_power += val; |
| 212 | sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); |
| 213 | } |
| 214 | #endif |
| 215 | |
Borislav Petkov | 91fcdd4 | 2006-10-19 23:28:29 -0700 | [diff] [blame] | 216 | /* |
| 217 | * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] |
| 218 | * to time slice values: [800ms ... 100ms ... 5ms] |
| 219 | * |
| 220 | * The higher a thread's priority, the bigger timeslices |
| 221 | * it gets during one round of execution. But even the lowest |
| 222 | * priority thread gets MIN_TIMESLICE worth of execution time. |
| 223 | */ |
| 224 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 225 | static inline unsigned int task_timeslice(struct task_struct *p) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 226 | { |
| 227 | return static_prio_timeslice(p->static_prio); |
| 228 | } |
| 229 | |
Ingo Molnar | e05606d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 230 | static inline int rt_policy(int policy) |
| 231 | { |
| 232 | if (unlikely(policy == SCHED_FIFO) || unlikely(policy == SCHED_RR)) |
| 233 | return 1; |
| 234 | return 0; |
| 235 | } |
| 236 | |
| 237 | static inline int task_has_rt_policy(struct task_struct *p) |
| 238 | { |
| 239 | return rt_policy(p->policy); |
| 240 | } |
| 241 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 242 | /* |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 243 | * This is the priority-queue data structure of the RT scheduling class: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 244 | */ |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 245 | struct rt_prio_array { |
| 246 | DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ |
| 247 | struct list_head queue[MAX_RT_PRIO]; |
| 248 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 249 | |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 250 | struct load_stat { |
| 251 | struct load_weight load; |
| 252 | u64 load_update_start, load_update_last; |
| 253 | unsigned long delta_fair, delta_exec, delta_stat; |
| 254 | }; |
| 255 | |
| 256 | /* CFS-related fields in a runqueue */ |
| 257 | struct cfs_rq { |
| 258 | struct load_weight load; |
| 259 | unsigned long nr_running; |
| 260 | |
| 261 | s64 fair_clock; |
| 262 | u64 exec_clock; |
| 263 | s64 wait_runtime; |
| 264 | u64 sleeper_bonus; |
| 265 | unsigned long wait_runtime_overruns, wait_runtime_underruns; |
| 266 | |
| 267 | struct rb_root tasks_timeline; |
| 268 | struct rb_node *rb_leftmost; |
| 269 | struct rb_node *rb_load_balance_curr; |
| 270 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 271 | /* 'curr' points to currently running entity on this cfs_rq. |
| 272 | * It is set to NULL otherwise (i.e when none are currently running). |
| 273 | */ |
| 274 | struct sched_entity *curr; |
| 275 | struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
| 276 | |
| 277 | /* leaf cfs_rqs are those that hold tasks (lowest schedulable entity in |
| 278 | * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
| 279 | * (like users, containers etc.) |
| 280 | * |
| 281 | * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This |
| 282 | * list is used during load balance. |
| 283 | */ |
| 284 | struct list_head leaf_cfs_rq_list; /* Better name : task_cfs_rq_list? */ |
| 285 | #endif |
| 286 | }; |
| 287 | |
| 288 | /* Real-Time classes' related field in a runqueue: */ |
| 289 | struct rt_rq { |
| 290 | struct rt_prio_array active; |
| 291 | int rt_load_balance_idx; |
| 292 | struct list_head *rt_load_balance_head, *rt_load_balance_curr; |
| 293 | }; |
| 294 | |
| 295 | /* |
| 296 | * The prio-array type of the old scheduler: |
| 297 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 298 | struct prio_array { |
| 299 | unsigned int nr_active; |
Steven Rostedt | d444886 | 2006-06-27 02:54:29 -0700 | [diff] [blame] | 300 | DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 301 | struct list_head queue[MAX_PRIO]; |
| 302 | }; |
| 303 | |
| 304 | /* |
| 305 | * This is the main, per-CPU runqueue data structure. |
| 306 | * |
| 307 | * Locking rule: those places that want to lock multiple runqueues |
| 308 | * (such as the load balancing or the thread migration code), lock |
| 309 | * acquire operations must be ordered by ascending &runqueue. |
| 310 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 311 | struct rq { |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 312 | spinlock_t lock; /* runqueue lock */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 313 | |
| 314 | /* |
| 315 | * nr_running and cpu_load should be in the same cacheline because |
| 316 | * remote CPUs use both these fields when doing load calculation. |
| 317 | */ |
| 318 | unsigned long nr_running; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 319 | unsigned long raw_weighted_load; |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 320 | #define CPU_LOAD_IDX_MAX 5 |
| 321 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; |
Siddha, Suresh B | bdecea3 | 2007-05-08 00:32:48 -0700 | [diff] [blame] | 322 | unsigned char idle_at_tick; |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 323 | #ifdef CONFIG_NO_HZ |
| 324 | unsigned char in_nohz_recently; |
| 325 | #endif |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 326 | struct load_stat ls; /* capture load from *all* tasks on this cpu */ |
| 327 | unsigned long nr_load_updates; |
| 328 | u64 nr_switches; |
| 329 | |
| 330 | struct cfs_rq cfs; |
| 331 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 332 | struct list_head leaf_cfs_rq_list; /* list of leaf cfs_rq on this cpu */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 333 | #endif |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 334 | struct rt_rq rt; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 335 | |
| 336 | /* |
| 337 | * This is part of a global counter where only the total sum |
| 338 | * over all CPUs matters. A task can increase this counter on |
| 339 | * one CPU and if it got migrated afterwards it may decrease |
| 340 | * it on another CPU. Always updated under the runqueue lock: |
| 341 | */ |
| 342 | unsigned long nr_uninterruptible; |
| 343 | |
| 344 | unsigned long expired_timestamp; |
Mike Galbraith | b18ec80 | 2006-12-10 02:20:31 -0800 | [diff] [blame] | 345 | unsigned long long most_recent_timestamp; |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 346 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 347 | struct task_struct *curr, *idle; |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 348 | unsigned long next_balance; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 349 | struct mm_struct *prev_mm; |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 350 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 351 | struct prio_array *active, *expired, arrays[2]; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 352 | int best_expired_prio; |
Ingo Molnar | 6aa645e | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 353 | |
| 354 | u64 clock, prev_clock_raw; |
| 355 | s64 clock_max_delta; |
| 356 | |
| 357 | unsigned int clock_warps, clock_overflows; |
| 358 | unsigned int clock_unstable_events; |
| 359 | |
| 360 | struct sched_class *load_balance_class; |
| 361 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 362 | atomic_t nr_iowait; |
| 363 | |
| 364 | #ifdef CONFIG_SMP |
| 365 | struct sched_domain *sd; |
| 366 | |
| 367 | /* For active balancing */ |
| 368 | int active_balance; |
| 369 | int push_cpu; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 370 | int cpu; /* cpu of this runqueue */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 371 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 372 | struct task_struct *migration_thread; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 373 | struct list_head migration_queue; |
| 374 | #endif |
| 375 | |
| 376 | #ifdef CONFIG_SCHEDSTATS |
| 377 | /* latency stats */ |
| 378 | struct sched_info rq_sched_info; |
| 379 | |
| 380 | /* sys_sched_yield() stats */ |
| 381 | unsigned long yld_exp_empty; |
| 382 | unsigned long yld_act_empty; |
| 383 | unsigned long yld_both_empty; |
| 384 | unsigned long yld_cnt; |
| 385 | |
| 386 | /* schedule() stats */ |
| 387 | unsigned long sched_switch; |
| 388 | unsigned long sched_cnt; |
| 389 | unsigned long sched_goidle; |
| 390 | |
| 391 | /* try_to_wake_up() stats */ |
| 392 | unsigned long ttwu_cnt; |
| 393 | unsigned long ttwu_local; |
| 394 | #endif |
Ingo Molnar | fcb9937 | 2006-07-03 00:25:10 -0700 | [diff] [blame] | 395 | struct lock_class_key rq_lock_key; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 396 | }; |
| 397 | |
Siddha, Suresh B | c339662 | 2007-05-08 00:33:09 -0700 | [diff] [blame] | 398 | static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 399 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 400 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 401 | static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
| 402 | { |
| 403 | rq->curr->sched_class->check_preempt_curr(rq, p); |
| 404 | } |
| 405 | |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 406 | static inline int cpu_of(struct rq *rq) |
| 407 | { |
| 408 | #ifdef CONFIG_SMP |
| 409 | return rq->cpu; |
| 410 | #else |
| 411 | return 0; |
| 412 | #endif |
| 413 | } |
| 414 | |
Nick Piggin | 674311d | 2005-06-25 14:57:27 -0700 | [diff] [blame] | 415 | /* |
Ingo Molnar | 20d315d | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 416 | * Per-runqueue clock, as finegrained as the platform can give us: |
| 417 | */ |
| 418 | static unsigned long long __rq_clock(struct rq *rq) |
| 419 | { |
| 420 | u64 prev_raw = rq->prev_clock_raw; |
| 421 | u64 now = sched_clock(); |
| 422 | s64 delta = now - prev_raw; |
| 423 | u64 clock = rq->clock; |
| 424 | |
| 425 | /* |
| 426 | * Protect against sched_clock() occasionally going backwards: |
| 427 | */ |
| 428 | if (unlikely(delta < 0)) { |
| 429 | clock++; |
| 430 | rq->clock_warps++; |
| 431 | } else { |
| 432 | /* |
| 433 | * Catch too large forward jumps too: |
| 434 | */ |
| 435 | if (unlikely(delta > 2*TICK_NSEC)) { |
| 436 | clock++; |
| 437 | rq->clock_overflows++; |
| 438 | } else { |
| 439 | if (unlikely(delta > rq->clock_max_delta)) |
| 440 | rq->clock_max_delta = delta; |
| 441 | clock += delta; |
| 442 | } |
| 443 | } |
| 444 | |
| 445 | rq->prev_clock_raw = now; |
| 446 | rq->clock = clock; |
| 447 | |
| 448 | return clock; |
| 449 | } |
| 450 | |
| 451 | static inline unsigned long long rq_clock(struct rq *rq) |
| 452 | { |
| 453 | int this_cpu = smp_processor_id(); |
| 454 | |
| 455 | if (this_cpu == cpu_of(rq)) |
| 456 | return __rq_clock(rq); |
| 457 | |
| 458 | return rq->clock; |
| 459 | } |
| 460 | |
| 461 | /* |
Nick Piggin | 674311d | 2005-06-25 14:57:27 -0700 | [diff] [blame] | 462 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 463 | * See detach_destroy_domains: synchronize_sched for details. |
Nick Piggin | 674311d | 2005-06-25 14:57:27 -0700 | [diff] [blame] | 464 | * |
| 465 | * The domain tree of any CPU may only be accessed from within |
| 466 | * preempt-disabled sections. |
| 467 | */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 468 | #define for_each_domain(cpu, __sd) \ |
| 469 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 470 | |
| 471 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) |
| 472 | #define this_rq() (&__get_cpu_var(runqueues)) |
| 473 | #define task_rq(p) cpu_rq(task_cpu(p)) |
| 474 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) |
| 475 | |
Ingo Molnar | 138a8ae | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 476 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 477 | /* Change a task's ->cfs_rq if it moves across CPUs */ |
| 478 | static inline void set_task_cfs_rq(struct task_struct *p) |
| 479 | { |
| 480 | p->se.cfs_rq = &task_rq(p)->cfs; |
| 481 | } |
| 482 | #else |
| 483 | static inline void set_task_cfs_rq(struct task_struct *p) |
| 484 | { |
| 485 | } |
| 486 | #endif |
| 487 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 488 | #ifndef prepare_arch_switch |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 489 | # define prepare_arch_switch(next) do { } while (0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 490 | #endif |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 491 | #ifndef finish_arch_switch |
| 492 | # define finish_arch_switch(prev) do { } while (0) |
| 493 | #endif |
| 494 | |
| 495 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 496 | static inline int task_running(struct rq *rq, struct task_struct *p) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 497 | { |
| 498 | return rq->curr == p; |
| 499 | } |
| 500 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 501 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 502 | { |
| 503 | } |
| 504 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 505 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 506 | { |
Ingo Molnar | da04c03 | 2005-09-13 11:17:59 +0200 | [diff] [blame] | 507 | #ifdef CONFIG_DEBUG_SPINLOCK |
| 508 | /* this is a valid case when another task releases the spinlock */ |
| 509 | rq->lock.owner = current; |
| 510 | #endif |
Ingo Molnar | 8a25d5d | 2006-07-03 00:24:54 -0700 | [diff] [blame] | 511 | /* |
| 512 | * If we are tracking spinlock dependencies then we have to |
| 513 | * fix up the runqueue lock - which gets 'carried over' from |
| 514 | * prev into current: |
| 515 | */ |
| 516 | spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); |
| 517 | |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 518 | spin_unlock_irq(&rq->lock); |
| 519 | } |
| 520 | |
| 521 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 522 | static inline int task_running(struct rq *rq, struct task_struct *p) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 523 | { |
| 524 | #ifdef CONFIG_SMP |
| 525 | return p->oncpu; |
| 526 | #else |
| 527 | return rq->curr == p; |
| 528 | #endif |
| 529 | } |
| 530 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 531 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 532 | { |
| 533 | #ifdef CONFIG_SMP |
| 534 | /* |
| 535 | * We can optimise this out completely for !SMP, because the |
| 536 | * SMP rebalancing from interrupt is the only thing that cares |
| 537 | * here. |
| 538 | */ |
| 539 | next->oncpu = 1; |
| 540 | #endif |
| 541 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| 542 | spin_unlock_irq(&rq->lock); |
| 543 | #else |
| 544 | spin_unlock(&rq->lock); |
| 545 | #endif |
| 546 | } |
| 547 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 548 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 549 | { |
| 550 | #ifdef CONFIG_SMP |
| 551 | /* |
| 552 | * After ->oncpu is cleared, the task can be moved to a different CPU. |
| 553 | * We must ensure this doesn't happen until the switch is completely |
| 554 | * finished. |
| 555 | */ |
| 556 | smp_wmb(); |
| 557 | prev->oncpu = 0; |
| 558 | #endif |
| 559 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| 560 | local_irq_enable(); |
| 561 | #endif |
| 562 | } |
| 563 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 564 | |
| 565 | /* |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 566 | * __task_rq_lock - lock the runqueue a given task resides on. |
| 567 | * Must be called interrupts disabled. |
| 568 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 569 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 570 | __acquires(rq->lock) |
| 571 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 572 | struct rq *rq; |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 573 | |
| 574 | repeat_lock_task: |
| 575 | rq = task_rq(p); |
| 576 | spin_lock(&rq->lock); |
| 577 | if (unlikely(rq != task_rq(p))) { |
| 578 | spin_unlock(&rq->lock); |
| 579 | goto repeat_lock_task; |
| 580 | } |
| 581 | return rq; |
| 582 | } |
| 583 | |
| 584 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 585 | * task_rq_lock - lock the runqueue a given task resides on and disable |
| 586 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
| 587 | * explicitly disabling preemption. |
| 588 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 589 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 590 | __acquires(rq->lock) |
| 591 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 592 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 593 | |
| 594 | repeat_lock_task: |
| 595 | local_irq_save(*flags); |
| 596 | rq = task_rq(p); |
| 597 | spin_lock(&rq->lock); |
| 598 | if (unlikely(rq != task_rq(p))) { |
| 599 | spin_unlock_irqrestore(&rq->lock, *flags); |
| 600 | goto repeat_lock_task; |
| 601 | } |
| 602 | return rq; |
| 603 | } |
| 604 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 605 | static inline void __task_rq_unlock(struct rq *rq) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 606 | __releases(rq->lock) |
| 607 | { |
| 608 | spin_unlock(&rq->lock); |
| 609 | } |
| 610 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 611 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 612 | __releases(rq->lock) |
| 613 | { |
| 614 | spin_unlock_irqrestore(&rq->lock, *flags); |
| 615 | } |
| 616 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 617 | /* |
Robert P. J. Day | cc2a73b | 2006-12-10 02:20:00 -0800 | [diff] [blame] | 618 | * this_rq_lock - lock this runqueue and disable interrupts. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 619 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 620 | static inline struct rq *this_rq_lock(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 621 | __acquires(rq->lock) |
| 622 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 623 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 624 | |
| 625 | local_irq_disable(); |
| 626 | rq = this_rq(); |
| 627 | spin_lock(&rq->lock); |
| 628 | |
| 629 | return rq; |
| 630 | } |
| 631 | |
Ingo Molnar | c24d20d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 632 | /* |
| 633 | * resched_task - mark a task 'to be rescheduled now'. |
| 634 | * |
| 635 | * On UP this means the setting of the need_resched flag, on SMP it |
| 636 | * might also involve a cross-CPU call to trigger the scheduler on |
| 637 | * the target CPU. |
| 638 | */ |
| 639 | #ifdef CONFIG_SMP |
| 640 | |
| 641 | #ifndef tsk_is_polling |
| 642 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) |
| 643 | #endif |
| 644 | |
| 645 | static void resched_task(struct task_struct *p) |
| 646 | { |
| 647 | int cpu; |
| 648 | |
| 649 | assert_spin_locked(&task_rq(p)->lock); |
| 650 | |
| 651 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) |
| 652 | return; |
| 653 | |
| 654 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); |
| 655 | |
| 656 | cpu = task_cpu(p); |
| 657 | if (cpu == smp_processor_id()) |
| 658 | return; |
| 659 | |
| 660 | /* NEED_RESCHED must be visible before we test polling */ |
| 661 | smp_mb(); |
| 662 | if (!tsk_is_polling(p)) |
| 663 | smp_send_reschedule(cpu); |
| 664 | } |
| 665 | |
| 666 | static void resched_cpu(int cpu) |
| 667 | { |
| 668 | struct rq *rq = cpu_rq(cpu); |
| 669 | unsigned long flags; |
| 670 | |
| 671 | if (!spin_trylock_irqsave(&rq->lock, flags)) |
| 672 | return; |
| 673 | resched_task(cpu_curr(cpu)); |
| 674 | spin_unlock_irqrestore(&rq->lock, flags); |
| 675 | } |
| 676 | #else |
| 677 | static inline void resched_task(struct task_struct *p) |
| 678 | { |
| 679 | assert_spin_locked(&task_rq(p)->lock); |
| 680 | set_tsk_need_resched(p); |
| 681 | } |
| 682 | #endif |
| 683 | |
Ingo Molnar | 45bf76d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 684 | static u64 div64_likely32(u64 divident, unsigned long divisor) |
| 685 | { |
| 686 | #if BITS_PER_LONG == 32 |
| 687 | if (likely(divident <= 0xffffffffULL)) |
| 688 | return (u32)divident / divisor; |
| 689 | do_div(divident, divisor); |
| 690 | |
| 691 | return divident; |
| 692 | #else |
| 693 | return divident / divisor; |
| 694 | #endif |
| 695 | } |
| 696 | |
| 697 | #if BITS_PER_LONG == 32 |
| 698 | # define WMULT_CONST (~0UL) |
| 699 | #else |
| 700 | # define WMULT_CONST (1UL << 32) |
| 701 | #endif |
| 702 | |
| 703 | #define WMULT_SHIFT 32 |
| 704 | |
| 705 | static inline unsigned long |
| 706 | calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
| 707 | struct load_weight *lw) |
| 708 | { |
| 709 | u64 tmp; |
| 710 | |
| 711 | if (unlikely(!lw->inv_weight)) |
| 712 | lw->inv_weight = WMULT_CONST / lw->weight; |
| 713 | |
| 714 | tmp = (u64)delta_exec * weight; |
| 715 | /* |
| 716 | * Check whether we'd overflow the 64-bit multiplication: |
| 717 | */ |
| 718 | if (unlikely(tmp > WMULT_CONST)) { |
| 719 | tmp = ((tmp >> WMULT_SHIFT/2) * lw->inv_weight) |
| 720 | >> (WMULT_SHIFT/2); |
| 721 | } else { |
| 722 | tmp = (tmp * lw->inv_weight) >> WMULT_SHIFT; |
| 723 | } |
| 724 | |
| 725 | return (unsigned long)min(tmp, (u64)sysctl_sched_runtime_limit); |
| 726 | } |
| 727 | |
| 728 | static inline unsigned long |
| 729 | calc_delta_fair(unsigned long delta_exec, struct load_weight *lw) |
| 730 | { |
| 731 | return calc_delta_mine(delta_exec, NICE_0_LOAD, lw); |
| 732 | } |
| 733 | |
| 734 | static void update_load_add(struct load_weight *lw, unsigned long inc) |
| 735 | { |
| 736 | lw->weight += inc; |
| 737 | lw->inv_weight = 0; |
| 738 | } |
| 739 | |
| 740 | static void update_load_sub(struct load_weight *lw, unsigned long dec) |
| 741 | { |
| 742 | lw->weight -= dec; |
| 743 | lw->inv_weight = 0; |
| 744 | } |
| 745 | |
| 746 | static void __update_curr_load(struct rq *rq, struct load_stat *ls) |
| 747 | { |
| 748 | if (rq->curr != rq->idle && ls->load.weight) { |
| 749 | ls->delta_exec += ls->delta_stat; |
| 750 | ls->delta_fair += calc_delta_fair(ls->delta_stat, &ls->load); |
| 751 | ls->delta_stat = 0; |
| 752 | } |
| 753 | } |
| 754 | |
| 755 | /* |
| 756 | * Update delta_exec, delta_fair fields for rq. |
| 757 | * |
| 758 | * delta_fair clock advances at a rate inversely proportional to |
| 759 | * total load (rq->ls.load.weight) on the runqueue, while |
| 760 | * delta_exec advances at the same rate as wall-clock (provided |
| 761 | * cpu is not idle). |
| 762 | * |
| 763 | * delta_exec / delta_fair is a measure of the (smoothened) load on this |
| 764 | * runqueue over any given interval. This (smoothened) load is used |
| 765 | * during load balance. |
| 766 | * |
| 767 | * This function is called /before/ updating rq->ls.load |
| 768 | * and when switching tasks. |
| 769 | */ |
| 770 | static void update_curr_load(struct rq *rq, u64 now) |
| 771 | { |
| 772 | struct load_stat *ls = &rq->ls; |
| 773 | u64 start; |
| 774 | |
| 775 | start = ls->load_update_start; |
| 776 | ls->load_update_start = now; |
| 777 | ls->delta_stat += now - start; |
| 778 | /* |
| 779 | * Stagger updates to ls->delta_fair. Very frequent updates |
| 780 | * can be expensive. |
| 781 | */ |
| 782 | if (ls->delta_stat >= sysctl_sched_stat_granularity) |
| 783 | __update_curr_load(rq, ls); |
| 784 | } |
| 785 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 786 | /* |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 787 | * To aid in avoiding the subversion of "niceness" due to uneven distribution |
| 788 | * of tasks with abnormal "nice" values across CPUs the contribution that |
| 789 | * each task makes to its run queue's load is weighted according to its |
| 790 | * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
| 791 | * scaled version of the new time slice allocation that they receive on time |
| 792 | * slice expiry etc. |
| 793 | */ |
| 794 | |
| 795 | /* |
| 796 | * Assume: static_prio_timeslice(NICE_TO_PRIO(0)) == DEF_TIMESLICE |
| 797 | * If static_prio_timeslice() is ever changed to break this assumption then |
| 798 | * this code will need modification |
| 799 | */ |
| 800 | #define TIME_SLICE_NICE_ZERO DEF_TIMESLICE |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 801 | #define load_weight(lp) \ |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 802 | (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO) |
| 803 | #define PRIO_TO_LOAD_WEIGHT(prio) \ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 804 | load_weight(static_prio_timeslice(prio)) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 805 | #define RTPRIO_TO_LOAD_WEIGHT(rp) \ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 806 | (PRIO_TO_LOAD_WEIGHT(MAX_RT_PRIO) + load_weight(rp)) |
| 807 | |
| 808 | #define WEIGHT_IDLEPRIO 2 |
| 809 | #define WMULT_IDLEPRIO (1 << 31) |
| 810 | |
| 811 | /* |
| 812 | * Nice levels are multiplicative, with a gentle 10% change for every |
| 813 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to |
| 814 | * nice 1, it will get ~10% less CPU time than another CPU-bound task |
| 815 | * that remained on nice 0. |
| 816 | * |
| 817 | * The "10% effect" is relative and cumulative: from _any_ nice level, |
| 818 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level |
| 819 | * it's +10% CPU usage. |
| 820 | */ |
| 821 | static const int prio_to_weight[40] = { |
| 822 | /* -20 */ 88818, 71054, 56843, 45475, 36380, 29104, 23283, 18626, 14901, 11921, |
| 823 | /* -10 */ 9537, 7629, 6103, 4883, 3906, 3125, 2500, 2000, 1600, 1280, |
| 824 | /* 0 */ NICE_0_LOAD /* 1024 */, |
| 825 | /* 1 */ 819, 655, 524, 419, 336, 268, 215, 172, 137, |
| 826 | /* 10 */ 110, 87, 70, 56, 45, 36, 29, 23, 18, 15, |
| 827 | }; |
| 828 | |
| 829 | static const u32 prio_to_wmult[40] = { |
| 830 | 48356, 60446, 75558, 94446, 118058, 147573, |
| 831 | 184467, 230589, 288233, 360285, 450347, |
| 832 | 562979, 703746, 879575, 1099582, 1374389, |
| 833 | 717986, 2147483, 2684354, 3355443, 4194304, |
| 834 | 244160, 6557201, 8196502, 10250518, 12782640, |
| 835 | 16025997, 19976592, 24970740, 31350126, 39045157, |
| 836 | 49367440, 61356675, 76695844, 95443717, 119304647, |
| 837 | 148102320, 186737708, 238609294, 286331153, |
| 838 | }; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 839 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 840 | static inline void |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 841 | inc_load(struct rq *rq, const struct task_struct *p, u64 now) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 842 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 843 | update_curr_load(rq, now); |
| 844 | update_load_add(&rq->ls.load, p->se.load.weight); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 845 | } |
| 846 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 847 | static inline void |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 848 | dec_load(struct rq *rq, const struct task_struct *p, u64 now) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 849 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 850 | update_curr_load(rq, now); |
| 851 | update_load_sub(&rq->ls.load, p->se.load.weight); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 852 | } |
| 853 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 854 | static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 855 | { |
| 856 | rq->nr_running++; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 857 | inc_load(rq, p, now); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 858 | } |
| 859 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 860 | static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 861 | { |
| 862 | rq->nr_running--; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 863 | dec_load(rq, p, now); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 864 | } |
| 865 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 866 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
| 867 | |
| 868 | /* |
| 869 | * runqueue iterator, to support SMP load-balancing between different |
| 870 | * scheduling classes, without having to expose their internal data |
| 871 | * structures to the load-balancing proper: |
| 872 | */ |
| 873 | struct rq_iterator { |
| 874 | void *arg; |
| 875 | struct task_struct *(*start)(void *); |
| 876 | struct task_struct *(*next)(void *); |
| 877 | }; |
| 878 | |
| 879 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| 880 | unsigned long max_nr_move, unsigned long max_load_move, |
| 881 | struct sched_domain *sd, enum cpu_idle_type idle, |
| 882 | int *all_pinned, unsigned long *load_moved, |
| 883 | int this_best_prio, int best_prio, int best_prio_seen, |
| 884 | struct rq_iterator *iterator); |
| 885 | |
| 886 | #include "sched_stats.h" |
| 887 | #include "sched_rt.c" |
| 888 | #include "sched_fair.c" |
| 889 | #include "sched_idletask.c" |
| 890 | #ifdef CONFIG_SCHED_DEBUG |
| 891 | # include "sched_debug.c" |
| 892 | #endif |
| 893 | |
| 894 | #define sched_class_highest (&rt_sched_class) |
| 895 | |
Ingo Molnar | 45bf76d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 896 | static void set_load_weight(struct task_struct *p) |
| 897 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 898 | task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime; |
| 899 | p->se.wait_runtime = 0; |
| 900 | |
Ingo Molnar | 45bf76d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 901 | if (task_has_rt_policy(p)) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 902 | p->se.load.weight = prio_to_weight[0] * 2; |
| 903 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; |
| 904 | return; |
| 905 | } |
| 906 | |
| 907 | /* |
| 908 | * SCHED_IDLE tasks get minimal weight: |
| 909 | */ |
| 910 | if (p->policy == SCHED_IDLE) { |
| 911 | p->se.load.weight = WEIGHT_IDLEPRIO; |
| 912 | p->se.load.inv_weight = WMULT_IDLEPRIO; |
| 913 | return; |
| 914 | } |
| 915 | |
| 916 | p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
| 917 | p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; |
Ingo Molnar | 45bf76d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 918 | } |
| 919 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 920 | static void |
| 921 | enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, u64 now) |
Ingo Molnar | 71f8bd4 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 922 | { |
| 923 | sched_info_queued(p); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 924 | p->sched_class->enqueue_task(rq, p, wakeup, now); |
| 925 | p->se.on_rq = 1; |
| 926 | } |
| 927 | |
| 928 | static void |
| 929 | dequeue_task(struct rq *rq, struct task_struct *p, int sleep, u64 now) |
| 930 | { |
| 931 | p->sched_class->dequeue_task(rq, p, sleep, now); |
| 932 | p->se.on_rq = 0; |
Ingo Molnar | 71f8bd4 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 933 | } |
| 934 | |
| 935 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 936 | * __normal_prio - return the priority that is based on the static prio |
Ingo Molnar | 71f8bd4 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 937 | */ |
Ingo Molnar | 1453118 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 938 | static inline int __normal_prio(struct task_struct *p) |
| 939 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 940 | return p->static_prio; |
Ingo Molnar | 1453118 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 941 | } |
| 942 | |
| 943 | /* |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 944 | * Calculate the expected normal priority: i.e. priority |
| 945 | * without taking RT-inheritance into account. Might be |
| 946 | * boosted by interactivity modifiers. Changes upon fork, |
| 947 | * setprio syscalls, and whenever the interactivity |
| 948 | * estimator recalculates. |
| 949 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 950 | static inline int normal_prio(struct task_struct *p) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 951 | { |
| 952 | int prio; |
| 953 | |
Ingo Molnar | e05606d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 954 | if (task_has_rt_policy(p)) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 955 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
| 956 | else |
| 957 | prio = __normal_prio(p); |
| 958 | return prio; |
| 959 | } |
| 960 | |
| 961 | /* |
| 962 | * Calculate the current priority, i.e. the priority |
| 963 | * taken into account by the scheduler. This value might |
| 964 | * be boosted by RT tasks, or might be boosted by |
| 965 | * interactivity modifiers. Will be RT if the task got |
| 966 | * RT-boosted. If not then it returns p->normal_prio. |
| 967 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 968 | static int effective_prio(struct task_struct *p) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 969 | { |
| 970 | p->normal_prio = normal_prio(p); |
| 971 | /* |
| 972 | * If we are RT tasks or we were boosted to RT priority, |
| 973 | * keep the priority unchanged. Otherwise, update priority |
| 974 | * to the normal priority: |
| 975 | */ |
| 976 | if (!rt_prio(p->prio)) |
| 977 | return p->normal_prio; |
| 978 | return p->prio; |
| 979 | } |
| 980 | |
| 981 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 982 | * activate_task - move a task to the runqueue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 983 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 984 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 985 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 986 | u64 now = rq_clock(rq); |
Con Kolivas | d425b27 | 2006-03-31 02:31:29 -0800 | [diff] [blame] | 987 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 988 | if (p->state == TASK_UNINTERRUPTIBLE) |
| 989 | rq->nr_uninterruptible--; |
| 990 | |
| 991 | enqueue_task(rq, p, wakeup, now); |
| 992 | inc_nr_running(p, rq, now); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 993 | } |
| 994 | |
| 995 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 996 | * activate_idle_task - move idle task to the _front_ of runqueue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 997 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 998 | static inline void activate_idle_task(struct task_struct *p, struct rq *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 999 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1000 | u64 now = rq_clock(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1001 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1002 | if (p->state == TASK_UNINTERRUPTIBLE) |
| 1003 | rq->nr_uninterruptible--; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1004 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1005 | enqueue_task(rq, p, 0, now); |
| 1006 | inc_nr_running(p, rq, now); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1007 | } |
| 1008 | |
| 1009 | /* |
| 1010 | * deactivate_task - remove a task from the runqueue. |
| 1011 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1012 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1013 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1014 | u64 now = rq_clock(rq); |
| 1015 | |
| 1016 | if (p->state == TASK_UNINTERRUPTIBLE) |
| 1017 | rq->nr_uninterruptible++; |
| 1018 | |
| 1019 | dequeue_task(rq, p, sleep, now); |
| 1020 | dec_nr_running(p, rq, now); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1021 | } |
| 1022 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1023 | /** |
| 1024 | * task_curr - is this task currently executing on a CPU? |
| 1025 | * @p: the task in question. |
| 1026 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1027 | inline int task_curr(const struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1028 | { |
| 1029 | return cpu_curr(task_cpu(p)) == p; |
| 1030 | } |
| 1031 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1032 | /* Used instead of source_load when we know the type == 0 */ |
| 1033 | unsigned long weighted_cpuload(const int cpu) |
| 1034 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1035 | return cpu_rq(cpu)->ls.load.weight; |
| 1036 | } |
| 1037 | |
| 1038 | static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) |
| 1039 | { |
| 1040 | #ifdef CONFIG_SMP |
| 1041 | task_thread_info(p)->cpu = cpu; |
| 1042 | set_task_cfs_rq(p); |
| 1043 | #endif |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1044 | } |
| 1045 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1046 | #ifdef CONFIG_SMP |
Ingo Molnar | c65cc87 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 1047 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1048 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
Ingo Molnar | c65cc87 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 1049 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1050 | int old_cpu = task_cpu(p); |
| 1051 | struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); |
| 1052 | u64 clock_offset, fair_clock_offset; |
| 1053 | |
| 1054 | clock_offset = old_rq->clock - new_rq->clock; |
| 1055 | fair_clock_offset = old_rq->cfs.fair_clock - |
| 1056 | new_rq->cfs.fair_clock; |
| 1057 | if (p->se.wait_start) |
| 1058 | p->se.wait_start -= clock_offset; |
| 1059 | if (p->se.wait_start_fair) |
| 1060 | p->se.wait_start_fair -= fair_clock_offset; |
| 1061 | if (p->se.sleep_start) |
| 1062 | p->se.sleep_start -= clock_offset; |
| 1063 | if (p->se.block_start) |
| 1064 | p->se.block_start -= clock_offset; |
| 1065 | if (p->se.sleep_start_fair) |
| 1066 | p->se.sleep_start_fair -= fair_clock_offset; |
| 1067 | |
| 1068 | __set_task_cpu(p, new_cpu); |
Ingo Molnar | c65cc87 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 1069 | } |
| 1070 | |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1071 | struct migration_req { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1072 | struct list_head list; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1073 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1074 | struct task_struct *task; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1075 | int dest_cpu; |
| 1076 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1077 | struct completion done; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1078 | }; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1079 | |
| 1080 | /* |
| 1081 | * The task's runqueue lock must be held. |
| 1082 | * Returns true if you have to wait for migration thread. |
| 1083 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1084 | static int |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1085 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1086 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1087 | struct rq *rq = task_rq(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1088 | |
| 1089 | /* |
| 1090 | * If the task is not on a runqueue (and not running), then |
| 1091 | * it is sufficient to simply update the task's cpu field. |
| 1092 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1093 | if (!p->se.on_rq && !task_running(rq, p)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1094 | set_task_cpu(p, dest_cpu); |
| 1095 | return 0; |
| 1096 | } |
| 1097 | |
| 1098 | init_completion(&req->done); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1099 | req->task = p; |
| 1100 | req->dest_cpu = dest_cpu; |
| 1101 | list_add(&req->list, &rq->migration_queue); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 1102 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1103 | return 1; |
| 1104 | } |
| 1105 | |
| 1106 | /* |
| 1107 | * wait_task_inactive - wait for a thread to unschedule. |
| 1108 | * |
| 1109 | * The caller must ensure that the task *will* unschedule sometime soon, |
| 1110 | * else this function might spin for a *long* time. This function can't |
| 1111 | * be called with interrupts off, or it may introduce deadlock with |
| 1112 | * smp_call_function() if an IPI is sent by the same process we are |
| 1113 | * waiting to become inactive. |
| 1114 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1115 | void wait_task_inactive(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1116 | { |
| 1117 | unsigned long flags; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1118 | int running, on_rq; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1119 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1120 | |
| 1121 | repeat: |
Linus Torvalds | fa490cf | 2007-06-18 09:34:40 -0700 | [diff] [blame] | 1122 | /* |
| 1123 | * We do the initial early heuristics without holding |
| 1124 | * any task-queue locks at all. We'll only try to get |
| 1125 | * the runqueue lock when things look like they will |
| 1126 | * work out! |
| 1127 | */ |
| 1128 | rq = task_rq(p); |
| 1129 | |
| 1130 | /* |
| 1131 | * If the task is actively running on another CPU |
| 1132 | * still, just relax and busy-wait without holding |
| 1133 | * any locks. |
| 1134 | * |
| 1135 | * NOTE! Since we don't hold any locks, it's not |
| 1136 | * even sure that "rq" stays as the right runqueue! |
| 1137 | * But we don't care, since "task_running()" will |
| 1138 | * return false if the runqueue has changed and p |
| 1139 | * is actually now running somewhere else! |
| 1140 | */ |
| 1141 | while (task_running(rq, p)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1142 | cpu_relax(); |
Linus Torvalds | fa490cf | 2007-06-18 09:34:40 -0700 | [diff] [blame] | 1143 | |
| 1144 | /* |
| 1145 | * Ok, time to look more closely! We need the rq |
| 1146 | * lock now, to be *sure*. If we're wrong, we'll |
| 1147 | * just go back and repeat. |
| 1148 | */ |
| 1149 | rq = task_rq_lock(p, &flags); |
| 1150 | running = task_running(rq, p); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1151 | on_rq = p->se.on_rq; |
Linus Torvalds | fa490cf | 2007-06-18 09:34:40 -0700 | [diff] [blame] | 1152 | task_rq_unlock(rq, &flags); |
| 1153 | |
| 1154 | /* |
| 1155 | * Was it really running after all now that we |
| 1156 | * checked with the proper locks actually held? |
| 1157 | * |
| 1158 | * Oops. Go back and try again.. |
| 1159 | */ |
| 1160 | if (unlikely(running)) { |
| 1161 | cpu_relax(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1162 | goto repeat; |
| 1163 | } |
Linus Torvalds | fa490cf | 2007-06-18 09:34:40 -0700 | [diff] [blame] | 1164 | |
| 1165 | /* |
| 1166 | * It's not enough that it's not actively running, |
| 1167 | * it must be off the runqueue _entirely_, and not |
| 1168 | * preempted! |
| 1169 | * |
| 1170 | * So if it wa still runnable (but just not actively |
| 1171 | * running right now), it's preempted, and we should |
| 1172 | * yield - it could be a while. |
| 1173 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1174 | if (unlikely(on_rq)) { |
Linus Torvalds | fa490cf | 2007-06-18 09:34:40 -0700 | [diff] [blame] | 1175 | yield(); |
| 1176 | goto repeat; |
| 1177 | } |
| 1178 | |
| 1179 | /* |
| 1180 | * Ahh, all good. It wasn't running, and it wasn't |
| 1181 | * runnable, which means that it will never become |
| 1182 | * running in the future either. We're all done! |
| 1183 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1184 | } |
| 1185 | |
| 1186 | /*** |
| 1187 | * kick_process - kick a running thread to enter/exit the kernel |
| 1188 | * @p: the to-be-kicked thread |
| 1189 | * |
| 1190 | * Cause a process which is running on another CPU to enter |
| 1191 | * kernel-mode, without any delay. (to get signals handled.) |
| 1192 | * |
| 1193 | * NOTE: this function doesnt have to take the runqueue lock, |
| 1194 | * because all it wants to ensure is that the remote task enters |
| 1195 | * the kernel. If the IPI races and the task has been migrated |
| 1196 | * to another CPU then no harm is done and the purpose has been |
| 1197 | * achieved as well. |
| 1198 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1199 | void kick_process(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1200 | { |
| 1201 | int cpu; |
| 1202 | |
| 1203 | preempt_disable(); |
| 1204 | cpu = task_cpu(p); |
| 1205 | if ((cpu != smp_processor_id()) && task_curr(p)) |
| 1206 | smp_send_reschedule(cpu); |
| 1207 | preempt_enable(); |
| 1208 | } |
| 1209 | |
| 1210 | /* |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1211 | * Return a low guess at the load of a migration-source cpu weighted |
| 1212 | * according to the scheduling class and "nice" value. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1213 | * |
| 1214 | * We want to under-estimate the load of migration sources, to |
| 1215 | * balance conservatively. |
| 1216 | */ |
Con Kolivas | b910472 | 2005-11-08 21:38:55 -0800 | [diff] [blame] | 1217 | static inline unsigned long source_load(int cpu, int type) |
| 1218 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1219 | struct rq *rq = cpu_rq(cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1220 | unsigned long total = weighted_cpuload(cpu); |
Nick Piggin | a200057 | 2006-02-10 01:51:02 -0800 | [diff] [blame] | 1221 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1222 | if (type == 0) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1223 | return total; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1224 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1225 | return min(rq->cpu_load[type-1], total); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1226 | } |
| 1227 | |
| 1228 | /* |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1229 | * Return a high guess at the load of a migration-target cpu weighted |
| 1230 | * according to the scheduling class and "nice" value. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1231 | */ |
Con Kolivas | b910472 | 2005-11-08 21:38:55 -0800 | [diff] [blame] | 1232 | static inline unsigned long target_load(int cpu, int type) |
| 1233 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1234 | struct rq *rq = cpu_rq(cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1235 | unsigned long total = weighted_cpuload(cpu); |
Nick Piggin | a200057 | 2006-02-10 01:51:02 -0800 | [diff] [blame] | 1236 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1237 | if (type == 0) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1238 | return total; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1239 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1240 | return max(rq->cpu_load[type-1], total); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1241 | } |
| 1242 | |
| 1243 | /* |
| 1244 | * Return the average load per task on the cpu's run queue |
| 1245 | */ |
| 1246 | static inline unsigned long cpu_avg_load_per_task(int cpu) |
| 1247 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1248 | struct rq *rq = cpu_rq(cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1249 | unsigned long total = weighted_cpuload(cpu); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1250 | unsigned long n = rq->nr_running; |
| 1251 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1252 | return n ? total / n : SCHED_LOAD_SCALE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1253 | } |
| 1254 | |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1255 | /* |
| 1256 | * find_idlest_group finds and returns the least busy CPU group within the |
| 1257 | * domain. |
| 1258 | */ |
| 1259 | static struct sched_group * |
| 1260 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) |
| 1261 | { |
| 1262 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; |
| 1263 | unsigned long min_load = ULONG_MAX, this_load = 0; |
| 1264 | int load_idx = sd->forkexec_idx; |
| 1265 | int imbalance = 100 + (sd->imbalance_pct-100)/2; |
| 1266 | |
| 1267 | do { |
| 1268 | unsigned long load, avg_load; |
| 1269 | int local_group; |
| 1270 | int i; |
| 1271 | |
M.Baris Demiray | da5a552 | 2005-09-10 00:26:09 -0700 | [diff] [blame] | 1272 | /* Skip over this group if it has no CPUs allowed */ |
| 1273 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) |
| 1274 | goto nextgroup; |
| 1275 | |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1276 | local_group = cpu_isset(this_cpu, group->cpumask); |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1277 | |
| 1278 | /* Tally up the load of all CPUs in the group */ |
| 1279 | avg_load = 0; |
| 1280 | |
| 1281 | for_each_cpu_mask(i, group->cpumask) { |
| 1282 | /* Bias balancing toward cpus of our domain */ |
| 1283 | if (local_group) |
| 1284 | load = source_load(i, load_idx); |
| 1285 | else |
| 1286 | load = target_load(i, load_idx); |
| 1287 | |
| 1288 | avg_load += load; |
| 1289 | } |
| 1290 | |
| 1291 | /* Adjust by relative CPU power of the group */ |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 1292 | avg_load = sg_div_cpu_power(group, |
| 1293 | avg_load * SCHED_LOAD_SCALE); |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1294 | |
| 1295 | if (local_group) { |
| 1296 | this_load = avg_load; |
| 1297 | this = group; |
| 1298 | } else if (avg_load < min_load) { |
| 1299 | min_load = avg_load; |
| 1300 | idlest = group; |
| 1301 | } |
M.Baris Demiray | da5a552 | 2005-09-10 00:26:09 -0700 | [diff] [blame] | 1302 | nextgroup: |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1303 | group = group->next; |
| 1304 | } while (group != sd->groups); |
| 1305 | |
| 1306 | if (!idlest || 100*this_load < imbalance*min_load) |
| 1307 | return NULL; |
| 1308 | return idlest; |
| 1309 | } |
| 1310 | |
| 1311 | /* |
Satoru Takeuchi | 0feaece | 2006-10-03 01:14:10 -0700 | [diff] [blame] | 1312 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1313 | */ |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 1314 | static int |
| 1315 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1316 | { |
M.Baris Demiray | da5a552 | 2005-09-10 00:26:09 -0700 | [diff] [blame] | 1317 | cpumask_t tmp; |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1318 | unsigned long load, min_load = ULONG_MAX; |
| 1319 | int idlest = -1; |
| 1320 | int i; |
| 1321 | |
M.Baris Demiray | da5a552 | 2005-09-10 00:26:09 -0700 | [diff] [blame] | 1322 | /* Traverse only the allowed CPUs */ |
| 1323 | cpus_and(tmp, group->cpumask, p->cpus_allowed); |
| 1324 | |
| 1325 | for_each_cpu_mask(i, tmp) { |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1326 | load = weighted_cpuload(i); |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1327 | |
| 1328 | if (load < min_load || (load == min_load && i == this_cpu)) { |
| 1329 | min_load = load; |
| 1330 | idlest = i; |
| 1331 | } |
| 1332 | } |
| 1333 | |
| 1334 | return idlest; |
| 1335 | } |
| 1336 | |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1337 | /* |
| 1338 | * sched_balance_self: balance the current task (running on cpu) in domains |
| 1339 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and |
| 1340 | * SD_BALANCE_EXEC. |
| 1341 | * |
| 1342 | * Balance, ie. select the least loaded group. |
| 1343 | * |
| 1344 | * Returns the target CPU number, or the same CPU if no balancing is needed. |
| 1345 | * |
| 1346 | * preempt must be disabled. |
| 1347 | */ |
| 1348 | static int sched_balance_self(int cpu, int flag) |
| 1349 | { |
| 1350 | struct task_struct *t = current; |
| 1351 | struct sched_domain *tmp, *sd = NULL; |
Nick Piggin | 147cbb4 | 2005-06-25 14:57:19 -0700 | [diff] [blame] | 1352 | |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 1353 | for_each_domain(cpu, tmp) { |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 1354 | /* |
| 1355 | * If power savings logic is enabled for a domain, stop there. |
| 1356 | */ |
| 1357 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
| 1358 | break; |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1359 | if (tmp->flags & flag) |
| 1360 | sd = tmp; |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 1361 | } |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1362 | |
| 1363 | while (sd) { |
| 1364 | cpumask_t span; |
| 1365 | struct sched_group *group; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 1366 | int new_cpu, weight; |
| 1367 | |
| 1368 | if (!(sd->flags & flag)) { |
| 1369 | sd = sd->child; |
| 1370 | continue; |
| 1371 | } |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1372 | |
| 1373 | span = sd->span; |
| 1374 | group = find_idlest_group(sd, t, cpu); |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 1375 | if (!group) { |
| 1376 | sd = sd->child; |
| 1377 | continue; |
| 1378 | } |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1379 | |
M.Baris Demiray | da5a552 | 2005-09-10 00:26:09 -0700 | [diff] [blame] | 1380 | new_cpu = find_idlest_cpu(group, t, cpu); |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 1381 | if (new_cpu == -1 || new_cpu == cpu) { |
| 1382 | /* Now try balancing at a lower domain level of cpu */ |
| 1383 | sd = sd->child; |
| 1384 | continue; |
| 1385 | } |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1386 | |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 1387 | /* Now try balancing at a lower domain level of new_cpu */ |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1388 | cpu = new_cpu; |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1389 | sd = NULL; |
| 1390 | weight = cpus_weight(span); |
| 1391 | for_each_domain(cpu, tmp) { |
| 1392 | if (weight <= cpus_weight(tmp->span)) |
| 1393 | break; |
| 1394 | if (tmp->flags & flag) |
| 1395 | sd = tmp; |
| 1396 | } |
| 1397 | /* while loop will break here if sd == NULL */ |
| 1398 | } |
| 1399 | |
| 1400 | return cpu; |
| 1401 | } |
| 1402 | |
| 1403 | #endif /* CONFIG_SMP */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1404 | |
| 1405 | /* |
| 1406 | * wake_idle() will wake a task on an idle cpu if task->cpu is |
| 1407 | * not idle and an idle cpu is available. The span of cpus to |
| 1408 | * search starts with cpus closest then further out as needed, |
| 1409 | * so we always favor a closer, idle cpu. |
| 1410 | * |
| 1411 | * Returns the CPU we should wake onto. |
| 1412 | */ |
| 1413 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1414 | static int wake_idle(int cpu, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1415 | { |
| 1416 | cpumask_t tmp; |
| 1417 | struct sched_domain *sd; |
| 1418 | int i; |
| 1419 | |
Siddha, Suresh B | 4953198 | 2007-05-08 00:33:01 -0700 | [diff] [blame] | 1420 | /* |
| 1421 | * If it is idle, then it is the best cpu to run this task. |
| 1422 | * |
| 1423 | * This cpu is also the best, if it has more than one task already. |
| 1424 | * Siblings must be also busy(in most cases) as they didn't already |
| 1425 | * pickup the extra load from this cpu and hence we need not check |
| 1426 | * sibling runqueue info. This will avoid the checks and cache miss |
| 1427 | * penalities associated with that. |
| 1428 | */ |
| 1429 | if (idle_cpu(cpu) || cpu_rq(cpu)->nr_running > 1) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1430 | return cpu; |
| 1431 | |
| 1432 | for_each_domain(cpu, sd) { |
| 1433 | if (sd->flags & SD_WAKE_IDLE) { |
Nick Piggin | e0f364f | 2005-06-25 14:57:06 -0700 | [diff] [blame] | 1434 | cpus_and(tmp, sd->span, p->cpus_allowed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1435 | for_each_cpu_mask(i, tmp) { |
| 1436 | if (idle_cpu(i)) |
| 1437 | return i; |
| 1438 | } |
| 1439 | } |
Nick Piggin | e0f364f | 2005-06-25 14:57:06 -0700 | [diff] [blame] | 1440 | else |
| 1441 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1442 | } |
| 1443 | return cpu; |
| 1444 | } |
| 1445 | #else |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1446 | static inline int wake_idle(int cpu, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1447 | { |
| 1448 | return cpu; |
| 1449 | } |
| 1450 | #endif |
| 1451 | |
| 1452 | /*** |
| 1453 | * try_to_wake_up - wake up a thread |
| 1454 | * @p: the to-be-woken-up thread |
| 1455 | * @state: the mask of task states that can be woken |
| 1456 | * @sync: do a synchronous wakeup? |
| 1457 | * |
| 1458 | * Put it on the run-queue if it's not already there. The "current" |
| 1459 | * thread is always on the run-queue (except when the actual |
| 1460 | * re-schedule is in progress), and as such you're allowed to do |
| 1461 | * the simpler "current->state = TASK_RUNNING" to mark yourself |
| 1462 | * runnable without the overhead of this. |
| 1463 | * |
| 1464 | * returns failure only if the task is already active. |
| 1465 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1466 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1467 | { |
| 1468 | int cpu, this_cpu, success = 0; |
| 1469 | unsigned long flags; |
| 1470 | long old_state; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1471 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1472 | #ifdef CONFIG_SMP |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1473 | struct sched_domain *sd, *this_sd = NULL; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1474 | unsigned long load, this_load; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1475 | int new_cpu; |
| 1476 | #endif |
| 1477 | |
| 1478 | rq = task_rq_lock(p, &flags); |
| 1479 | old_state = p->state; |
| 1480 | if (!(old_state & state)) |
| 1481 | goto out; |
| 1482 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1483 | if (p->se.on_rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1484 | goto out_running; |
| 1485 | |
| 1486 | cpu = task_cpu(p); |
| 1487 | this_cpu = smp_processor_id(); |
| 1488 | |
| 1489 | #ifdef CONFIG_SMP |
| 1490 | if (unlikely(task_running(rq, p))) |
| 1491 | goto out_activate; |
| 1492 | |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1493 | new_cpu = cpu; |
| 1494 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1495 | schedstat_inc(rq, ttwu_cnt); |
| 1496 | if (cpu == this_cpu) { |
| 1497 | schedstat_inc(rq, ttwu_local); |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1498 | goto out_set_cpu; |
| 1499 | } |
| 1500 | |
| 1501 | for_each_domain(this_cpu, sd) { |
| 1502 | if (cpu_isset(cpu, sd->span)) { |
| 1503 | schedstat_inc(sd, ttwu_wake_remote); |
| 1504 | this_sd = sd; |
| 1505 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1506 | } |
| 1507 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1508 | |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1509 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1510 | goto out_set_cpu; |
| 1511 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1512 | /* |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1513 | * Check for affine wakeup and passive balancing possibilities. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1514 | */ |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1515 | if (this_sd) { |
| 1516 | int idx = this_sd->wake_idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1517 | unsigned int imbalance; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1518 | |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1519 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
| 1520 | |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1521 | load = source_load(cpu, idx); |
| 1522 | this_load = target_load(this_cpu, idx); |
| 1523 | |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 1524 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
| 1525 | |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1526 | if (this_sd->flags & SD_WAKE_AFFINE) { |
| 1527 | unsigned long tl = this_load; |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 1528 | unsigned long tl_per_task; |
| 1529 | |
| 1530 | tl_per_task = cpu_avg_load_per_task(this_cpu); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1531 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1532 | /* |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1533 | * If sync wakeup then subtract the (maximum possible) |
| 1534 | * effect of the currently running task from the load |
| 1535 | * of the current CPU: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1536 | */ |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1537 | if (sync) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1538 | tl -= current->se.load.weight; |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1539 | |
| 1540 | if ((tl <= load && |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 1541 | tl + target_load(cpu, idx) <= tl_per_task) || |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1542 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
Nick Piggin | a3f21bc | 2005-06-25 14:57:15 -0700 | [diff] [blame] | 1543 | /* |
| 1544 | * This domain has SD_WAKE_AFFINE and |
| 1545 | * p is cache cold in this domain, and |
| 1546 | * there is no bad imbalance. |
| 1547 | */ |
| 1548 | schedstat_inc(this_sd, ttwu_move_affine); |
| 1549 | goto out_set_cpu; |
| 1550 | } |
| 1551 | } |
| 1552 | |
| 1553 | /* |
| 1554 | * Start passive balancing when half the imbalance_pct |
| 1555 | * limit is reached. |
| 1556 | */ |
| 1557 | if (this_sd->flags & SD_WAKE_BALANCE) { |
| 1558 | if (imbalance*this_load <= 100*load) { |
| 1559 | schedstat_inc(this_sd, ttwu_move_balance); |
| 1560 | goto out_set_cpu; |
| 1561 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1562 | } |
| 1563 | } |
| 1564 | |
| 1565 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ |
| 1566 | out_set_cpu: |
| 1567 | new_cpu = wake_idle(new_cpu, p); |
| 1568 | if (new_cpu != cpu) { |
| 1569 | set_task_cpu(p, new_cpu); |
| 1570 | task_rq_unlock(rq, &flags); |
| 1571 | /* might preempt at this point */ |
| 1572 | rq = task_rq_lock(p, &flags); |
| 1573 | old_state = p->state; |
| 1574 | if (!(old_state & state)) |
| 1575 | goto out; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1576 | if (p->se.on_rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1577 | goto out_running; |
| 1578 | |
| 1579 | this_cpu = smp_processor_id(); |
| 1580 | cpu = task_cpu(p); |
| 1581 | } |
| 1582 | |
| 1583 | out_activate: |
| 1584 | #endif /* CONFIG_SMP */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1585 | activate_task(rq, p, 1); |
Ingo Molnar | d79fc0f | 2005-09-10 00:26:12 -0700 | [diff] [blame] | 1586 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1587 | * Sync wakeups (i.e. those types of wakeups where the waker |
| 1588 | * has indicated that it will leave the CPU in short order) |
| 1589 | * don't trigger a preemption, if the woken up task will run on |
| 1590 | * this cpu. (in this case the 'I will reschedule' promise of |
| 1591 | * the waker guarantees that the freshly woken up task is going |
| 1592 | * to be considered on this CPU.) |
| 1593 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1594 | if (!sync || cpu != this_cpu) |
| 1595 | check_preempt_curr(rq, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1596 | success = 1; |
| 1597 | |
| 1598 | out_running: |
| 1599 | p->state = TASK_RUNNING; |
| 1600 | out: |
| 1601 | task_rq_unlock(rq, &flags); |
| 1602 | |
| 1603 | return success; |
| 1604 | } |
| 1605 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1606 | int fastcall wake_up_process(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1607 | { |
| 1608 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | |
| 1609 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); |
| 1610 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1611 | EXPORT_SYMBOL(wake_up_process); |
| 1612 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1613 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1614 | { |
| 1615 | return try_to_wake_up(p, state, 0); |
| 1616 | } |
| 1617 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1618 | /* |
| 1619 | * Perform scheduler related setup for a newly forked process p. |
| 1620 | * p is forked by current. |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1621 | * |
| 1622 | * __sched_fork() is basic setup used by init_idle() too: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1623 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1624 | static void __sched_fork(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1625 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1626 | p->se.wait_start_fair = 0; |
| 1627 | p->se.wait_start = 0; |
| 1628 | p->se.exec_start = 0; |
| 1629 | p->se.sum_exec_runtime = 0; |
| 1630 | p->se.delta_exec = 0; |
| 1631 | p->se.delta_fair_run = 0; |
| 1632 | p->se.delta_fair_sleep = 0; |
| 1633 | p->se.wait_runtime = 0; |
| 1634 | p->se.sum_wait_runtime = 0; |
| 1635 | p->se.sum_sleep_runtime = 0; |
| 1636 | p->se.sleep_start = 0; |
| 1637 | p->se.sleep_start_fair = 0; |
| 1638 | p->se.block_start = 0; |
| 1639 | p->se.sleep_max = 0; |
| 1640 | p->se.block_max = 0; |
| 1641 | p->se.exec_max = 0; |
| 1642 | p->se.wait_max = 0; |
| 1643 | p->se.wait_runtime_overruns = 0; |
| 1644 | p->se.wait_runtime_underruns = 0; |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1645 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1646 | INIT_LIST_HEAD(&p->run_list); |
| 1647 | p->se.on_rq = 0; |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1648 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1649 | /* |
| 1650 | * We mark the process as running here, but have not actually |
| 1651 | * inserted it onto the runqueue yet. This guarantees that |
| 1652 | * nobody will actually run it, and a signal or other external |
| 1653 | * event cannot wake it up and insert it on the runqueue either. |
| 1654 | */ |
| 1655 | p->state = TASK_RUNNING; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1656 | } |
| 1657 | |
| 1658 | /* |
| 1659 | * fork()/clone()-time setup: |
| 1660 | */ |
| 1661 | void sched_fork(struct task_struct *p, int clone_flags) |
| 1662 | { |
| 1663 | int cpu = get_cpu(); |
| 1664 | |
| 1665 | __sched_fork(p); |
| 1666 | |
| 1667 | #ifdef CONFIG_SMP |
| 1668 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); |
| 1669 | #endif |
| 1670 | __set_task_cpu(p, cpu); |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 1671 | |
| 1672 | /* |
| 1673 | * Make sure we do not leak PI boosting priority to the child: |
| 1674 | */ |
| 1675 | p->prio = current->normal_prio; |
| 1676 | |
Chandra Seetharaman | 52f17b6 | 2006-07-14 00:24:38 -0700 | [diff] [blame] | 1677 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1678 | if (likely(sched_info_on())) |
Chandra Seetharaman | 52f17b6 | 2006-07-14 00:24:38 -0700 | [diff] [blame] | 1679 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1680 | #endif |
Chen, Kenneth W | d6077cb | 2006-02-14 13:53:10 -0800 | [diff] [blame] | 1681 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1682 | p->oncpu = 0; |
| 1683 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1684 | #ifdef CONFIG_PREEMPT |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1685 | /* Want to start with kernel preemption disabled. */ |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 1686 | task_thread_info(p)->preempt_count = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1687 | #endif |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 1688 | put_cpu(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1689 | } |
| 1690 | |
| 1691 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1692 | * After fork, child runs first. (default) If set to 0 then |
| 1693 | * parent will (try to) run first. |
| 1694 | */ |
| 1695 | unsigned int __read_mostly sysctl_sched_child_runs_first = 1; |
| 1696 | |
| 1697 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1698 | * wake_up_new_task - wake up a newly created task for the first time. |
| 1699 | * |
| 1700 | * This function will do some initial scheduler statistics housekeeping |
| 1701 | * that must be done for every newly created context, then puts the task |
| 1702 | * on the runqueue and wakes it. |
| 1703 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1704 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1705 | { |
| 1706 | unsigned long flags; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1707 | struct rq *rq; |
| 1708 | int this_cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1709 | |
| 1710 | rq = task_rq_lock(p, &flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1711 | BUG_ON(p->state != TASK_RUNNING); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1712 | this_cpu = smp_processor_id(); /* parent's CPU */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1713 | |
| 1714 | p->prio = effective_prio(p); |
| 1715 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1716 | if (!sysctl_sched_child_runs_first || (clone_flags & CLONE_VM) || |
| 1717 | task_cpu(p) != this_cpu || !current->se.on_rq) { |
| 1718 | activate_task(rq, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1719 | } else { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1720 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1721 | * Let the scheduling class do new task startup |
| 1722 | * management (if any): |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1723 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1724 | p->sched_class->task_new(rq, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1725 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1726 | check_preempt_curr(rq, p); |
| 1727 | task_rq_unlock(rq, &flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1728 | } |
| 1729 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1730 | /** |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1731 | * prepare_task_switch - prepare to switch tasks |
| 1732 | * @rq: the runqueue preparing to switch |
| 1733 | * @next: the task we are going to switch to. |
| 1734 | * |
| 1735 | * This is called with the rq lock held and interrupts off. It must |
| 1736 | * be paired with a subsequent finish_task_switch after the context |
| 1737 | * switch. |
| 1738 | * |
| 1739 | * prepare_task_switch sets up locking and calls architecture specific |
| 1740 | * hooks. |
| 1741 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1742 | static inline void prepare_task_switch(struct rq *rq, struct task_struct *next) |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1743 | { |
| 1744 | prepare_lock_switch(rq, next); |
| 1745 | prepare_arch_switch(next); |
| 1746 | } |
| 1747 | |
| 1748 | /** |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1749 | * finish_task_switch - clean up after a task-switch |
Jeff Garzik | 344baba | 2005-09-07 01:15:17 -0400 | [diff] [blame] | 1750 | * @rq: runqueue associated with task-switch |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1751 | * @prev: the thread we just switched away from. |
| 1752 | * |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1753 | * finish_task_switch must be called after the context switch, paired |
| 1754 | * with a prepare_task_switch call before the context switch. |
| 1755 | * finish_task_switch will reconcile locking set up by prepare_task_switch, |
| 1756 | * and do any other architecture-specific cleanup actions. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1757 | * |
| 1758 | * Note that we may have delayed dropping an mm in context_switch(). If |
| 1759 | * so, we finish that here outside of the runqueue lock. (Doing it |
| 1760 | * with the lock held can cause deadlocks; see schedule() for |
| 1761 | * details.) |
| 1762 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1763 | static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1764 | __releases(rq->lock) |
| 1765 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1766 | struct mm_struct *mm = rq->prev_mm; |
Oleg Nesterov | 55a101f | 2006-09-29 02:01:10 -0700 | [diff] [blame] | 1767 | long prev_state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1768 | |
| 1769 | rq->prev_mm = NULL; |
| 1770 | |
| 1771 | /* |
| 1772 | * A task struct has one reference for the use as "current". |
Oleg Nesterov | c394cc9 | 2006-09-29 02:01:11 -0700 | [diff] [blame] | 1773 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
Oleg Nesterov | 55a101f | 2006-09-29 02:01:10 -0700 | [diff] [blame] | 1774 | * schedule one last time. The schedule call will never return, and |
| 1775 | * the scheduled task must drop that reference. |
Oleg Nesterov | c394cc9 | 2006-09-29 02:01:11 -0700 | [diff] [blame] | 1776 | * The test for TASK_DEAD must occur while the runqueue locks are |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1777 | * still held, otherwise prev could be scheduled on another cpu, die |
| 1778 | * there before we look at prev->state, and then the reference would |
| 1779 | * be dropped twice. |
| 1780 | * Manfred Spraul <manfred@colorfullife.com> |
| 1781 | */ |
Oleg Nesterov | 55a101f | 2006-09-29 02:01:10 -0700 | [diff] [blame] | 1782 | prev_state = prev->state; |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1783 | finish_arch_switch(prev); |
| 1784 | finish_lock_switch(rq, prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1785 | if (mm) |
| 1786 | mmdrop(mm); |
Oleg Nesterov | c394cc9 | 2006-09-29 02:01:11 -0700 | [diff] [blame] | 1787 | if (unlikely(prev_state == TASK_DEAD)) { |
bibo mao | c6fd91f | 2006-03-26 01:38:20 -0800 | [diff] [blame] | 1788 | /* |
| 1789 | * Remove function-return probe instances associated with this |
| 1790 | * task and put them back on the free list. |
| 1791 | */ |
| 1792 | kprobe_flush_task(prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1793 | put_task_struct(prev); |
bibo mao | c6fd91f | 2006-03-26 01:38:20 -0800 | [diff] [blame] | 1794 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1795 | } |
| 1796 | |
| 1797 | /** |
| 1798 | * schedule_tail - first thing a freshly forked thread must call. |
| 1799 | * @prev: the thread we just switched away from. |
| 1800 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1801 | asmlinkage void schedule_tail(struct task_struct *prev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1802 | __releases(rq->lock) |
| 1803 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1804 | struct rq *rq = this_rq(); |
| 1805 | |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 1806 | finish_task_switch(rq, prev); |
| 1807 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
| 1808 | /* In this case, finish_task_switch does not reenable preemption */ |
| 1809 | preempt_enable(); |
| 1810 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1811 | if (current->set_child_tid) |
| 1812 | put_user(current->pid, current->set_child_tid); |
| 1813 | } |
| 1814 | |
| 1815 | /* |
| 1816 | * context_switch - switch to the new MM and the new |
| 1817 | * thread's register state. |
| 1818 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1819 | static inline void |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 1820 | context_switch(struct rq *rq, struct task_struct *prev, |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 1821 | struct task_struct *next) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1822 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1823 | struct mm_struct *mm, *oldmm; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1824 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1825 | prepare_task_switch(rq, next); |
| 1826 | mm = next->mm; |
| 1827 | oldmm = prev->active_mm; |
Zachary Amsden | 9226d12 | 2007-02-13 13:26:21 +0100 | [diff] [blame] | 1828 | /* |
| 1829 | * For paravirt, this is coupled with an exit in switch_to to |
| 1830 | * combine the page table reload and the switch backend into |
| 1831 | * one hypercall. |
| 1832 | */ |
| 1833 | arch_enter_lazy_cpu_mode(); |
| 1834 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1835 | if (unlikely(!mm)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1836 | next->active_mm = oldmm; |
| 1837 | atomic_inc(&oldmm->mm_count); |
| 1838 | enter_lazy_tlb(oldmm, next); |
| 1839 | } else |
| 1840 | switch_mm(oldmm, mm, next); |
| 1841 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1842 | if (unlikely(!prev->mm)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1843 | prev->active_mm = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1844 | rq->prev_mm = oldmm; |
| 1845 | } |
Ingo Molnar | 3a5f5e4 | 2006-07-14 00:24:27 -0700 | [diff] [blame] | 1846 | /* |
| 1847 | * Since the runqueue lock will be released by the next |
| 1848 | * task (which is an invalid locking op but in the case |
| 1849 | * of the scheduler it's an obvious special-case), so we |
| 1850 | * do an early lockdep release here: |
| 1851 | */ |
| 1852 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
Ingo Molnar | 8a25d5d | 2006-07-03 00:24:54 -0700 | [diff] [blame] | 1853 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
Ingo Molnar | 3a5f5e4 | 2006-07-14 00:24:27 -0700 | [diff] [blame] | 1854 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1855 | |
| 1856 | /* Here we just switch the register state and the stack. */ |
| 1857 | switch_to(prev, next, prev); |
| 1858 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1859 | barrier(); |
| 1860 | /* |
| 1861 | * this_rq must be evaluated again because prev may have moved |
| 1862 | * CPUs since it called schedule(), thus the 'rq' on its stack |
| 1863 | * frame will be invalid. |
| 1864 | */ |
| 1865 | finish_task_switch(this_rq(), prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1866 | } |
| 1867 | |
| 1868 | /* |
| 1869 | * nr_running, nr_uninterruptible and nr_context_switches: |
| 1870 | * |
| 1871 | * externally visible scheduler statistics: current number of runnable |
| 1872 | * threads, current number of uninterruptible-sleeping threads, total |
| 1873 | * number of context switches performed since bootup. |
| 1874 | */ |
| 1875 | unsigned long nr_running(void) |
| 1876 | { |
| 1877 | unsigned long i, sum = 0; |
| 1878 | |
| 1879 | for_each_online_cpu(i) |
| 1880 | sum += cpu_rq(i)->nr_running; |
| 1881 | |
| 1882 | return sum; |
| 1883 | } |
| 1884 | |
| 1885 | unsigned long nr_uninterruptible(void) |
| 1886 | { |
| 1887 | unsigned long i, sum = 0; |
| 1888 | |
KAMEZAWA Hiroyuki | 0a94502 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 1889 | for_each_possible_cpu(i) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1890 | sum += cpu_rq(i)->nr_uninterruptible; |
| 1891 | |
| 1892 | /* |
| 1893 | * Since we read the counters lockless, it might be slightly |
| 1894 | * inaccurate. Do not allow it to go below zero though: |
| 1895 | */ |
| 1896 | if (unlikely((long)sum < 0)) |
| 1897 | sum = 0; |
| 1898 | |
| 1899 | return sum; |
| 1900 | } |
| 1901 | |
| 1902 | unsigned long long nr_context_switches(void) |
| 1903 | { |
Steven Rostedt | cc94abf | 2006-06-27 02:54:31 -0700 | [diff] [blame] | 1904 | int i; |
| 1905 | unsigned long long sum = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1906 | |
KAMEZAWA Hiroyuki | 0a94502 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 1907 | for_each_possible_cpu(i) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1908 | sum += cpu_rq(i)->nr_switches; |
| 1909 | |
| 1910 | return sum; |
| 1911 | } |
| 1912 | |
| 1913 | unsigned long nr_iowait(void) |
| 1914 | { |
| 1915 | unsigned long i, sum = 0; |
| 1916 | |
KAMEZAWA Hiroyuki | 0a94502 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 1917 | for_each_possible_cpu(i) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1918 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
| 1919 | |
| 1920 | return sum; |
| 1921 | } |
| 1922 | |
Jack Steiner | db1b1fe | 2006-03-31 02:31:21 -0800 | [diff] [blame] | 1923 | unsigned long nr_active(void) |
| 1924 | { |
| 1925 | unsigned long i, running = 0, uninterruptible = 0; |
| 1926 | |
| 1927 | for_each_online_cpu(i) { |
| 1928 | running += cpu_rq(i)->nr_running; |
| 1929 | uninterruptible += cpu_rq(i)->nr_uninterruptible; |
| 1930 | } |
| 1931 | |
| 1932 | if (unlikely((long)uninterruptible < 0)) |
| 1933 | uninterruptible = 0; |
| 1934 | |
| 1935 | return running + uninterruptible; |
| 1936 | } |
| 1937 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1938 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1939 | * Update rq->cpu_load[] statistics. This function is usually called every |
| 1940 | * scheduler tick (TICK_NSEC). |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 1941 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1942 | static void update_cpu_load(struct rq *this_rq) |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 1943 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1944 | u64 fair_delta64, exec_delta64, idle_delta64, sample_interval64, tmp64; |
| 1945 | unsigned long total_load = this_rq->ls.load.weight; |
| 1946 | unsigned long this_load = total_load; |
| 1947 | struct load_stat *ls = &this_rq->ls; |
| 1948 | u64 now = __rq_clock(this_rq); |
| 1949 | int i, scale; |
| 1950 | |
| 1951 | this_rq->nr_load_updates++; |
| 1952 | if (unlikely(!(sysctl_sched_features & SCHED_FEAT_PRECISE_CPU_LOAD))) |
| 1953 | goto do_avg; |
| 1954 | |
| 1955 | /* Update delta_fair/delta_exec fields first */ |
| 1956 | update_curr_load(this_rq, now); |
| 1957 | |
| 1958 | fair_delta64 = ls->delta_fair + 1; |
| 1959 | ls->delta_fair = 0; |
| 1960 | |
| 1961 | exec_delta64 = ls->delta_exec + 1; |
| 1962 | ls->delta_exec = 0; |
| 1963 | |
| 1964 | sample_interval64 = now - ls->load_update_last; |
| 1965 | ls->load_update_last = now; |
| 1966 | |
| 1967 | if ((s64)sample_interval64 < (s64)TICK_NSEC) |
| 1968 | sample_interval64 = TICK_NSEC; |
| 1969 | |
| 1970 | if (exec_delta64 > sample_interval64) |
| 1971 | exec_delta64 = sample_interval64; |
| 1972 | |
| 1973 | idle_delta64 = sample_interval64 - exec_delta64; |
| 1974 | |
| 1975 | tmp64 = div64_64(SCHED_LOAD_SCALE * exec_delta64, fair_delta64); |
| 1976 | tmp64 = div64_64(tmp64 * exec_delta64, sample_interval64); |
| 1977 | |
| 1978 | this_load = (unsigned long)tmp64; |
| 1979 | |
| 1980 | do_avg: |
| 1981 | |
| 1982 | /* Update our load: */ |
| 1983 | for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
| 1984 | unsigned long old_load, new_load; |
| 1985 | |
| 1986 | /* scale is effectively 1 << i now, and >> i divides by scale */ |
| 1987 | |
| 1988 | old_load = this_rq->cpu_load[i]; |
| 1989 | new_load = this_load; |
| 1990 | |
| 1991 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
| 1992 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 1993 | } |
| 1994 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 1995 | #ifdef CONFIG_SMP |
| 1996 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 1997 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1998 | * double_rq_lock - safely lock two runqueues |
| 1999 | * |
| 2000 | * Note this does not disable interrupts like task_rq_lock, |
| 2001 | * you need to do so manually before calling. |
| 2002 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2003 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2004 | __acquires(rq1->lock) |
| 2005 | __acquires(rq2->lock) |
| 2006 | { |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 2007 | BUG_ON(!irqs_disabled()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2008 | if (rq1 == rq2) { |
| 2009 | spin_lock(&rq1->lock); |
| 2010 | __acquire(rq2->lock); /* Fake it out ;) */ |
| 2011 | } else { |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 2012 | if (rq1 < rq2) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2013 | spin_lock(&rq1->lock); |
| 2014 | spin_lock(&rq2->lock); |
| 2015 | } else { |
| 2016 | spin_lock(&rq2->lock); |
| 2017 | spin_lock(&rq1->lock); |
| 2018 | } |
| 2019 | } |
| 2020 | } |
| 2021 | |
| 2022 | /* |
| 2023 | * double_rq_unlock - safely unlock two runqueues |
| 2024 | * |
| 2025 | * Note this does not restore interrupts like task_rq_unlock, |
| 2026 | * you need to do so manually after calling. |
| 2027 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2028 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2029 | __releases(rq1->lock) |
| 2030 | __releases(rq2->lock) |
| 2031 | { |
| 2032 | spin_unlock(&rq1->lock); |
| 2033 | if (rq1 != rq2) |
| 2034 | spin_unlock(&rq2->lock); |
| 2035 | else |
| 2036 | __release(rq2->lock); |
| 2037 | } |
| 2038 | |
| 2039 | /* |
| 2040 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. |
| 2041 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2042 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2043 | __releases(this_rq->lock) |
| 2044 | __acquires(busiest->lock) |
| 2045 | __acquires(this_rq->lock) |
| 2046 | { |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 2047 | if (unlikely(!irqs_disabled())) { |
| 2048 | /* printk() doesn't work good under rq->lock */ |
| 2049 | spin_unlock(&this_rq->lock); |
| 2050 | BUG_ON(1); |
| 2051 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2052 | if (unlikely(!spin_trylock(&busiest->lock))) { |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 2053 | if (busiest < this_rq) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2054 | spin_unlock(&this_rq->lock); |
| 2055 | spin_lock(&busiest->lock); |
| 2056 | spin_lock(&this_rq->lock); |
| 2057 | } else |
| 2058 | spin_lock(&busiest->lock); |
| 2059 | } |
| 2060 | } |
| 2061 | |
| 2062 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2063 | * If dest_cpu is allowed for this process, migrate the task to it. |
| 2064 | * This is accomplished by forcing the cpu_allowed mask to only |
| 2065 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
| 2066 | * the cpu_allowed mask is restored. |
| 2067 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 2068 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2069 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2070 | struct migration_req req; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2071 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2072 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2073 | |
| 2074 | rq = task_rq_lock(p, &flags); |
| 2075 | if (!cpu_isset(dest_cpu, p->cpus_allowed) |
| 2076 | || unlikely(cpu_is_offline(dest_cpu))) |
| 2077 | goto out; |
| 2078 | |
| 2079 | /* force the process onto the specified CPU */ |
| 2080 | if (migrate_task(p, dest_cpu, &req)) { |
| 2081 | /* Need to wait for migration thread (might exit: take ref). */ |
| 2082 | struct task_struct *mt = rq->migration_thread; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 2083 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2084 | get_task_struct(mt); |
| 2085 | task_rq_unlock(rq, &flags); |
| 2086 | wake_up_process(mt); |
| 2087 | put_task_struct(mt); |
| 2088 | wait_for_completion(&req.done); |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 2089 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2090 | return; |
| 2091 | } |
| 2092 | out: |
| 2093 | task_rq_unlock(rq, &flags); |
| 2094 | } |
| 2095 | |
| 2096 | /* |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 2097 | * sched_exec - execve() is a valuable balancing opportunity, because at |
| 2098 | * this point the task has the smallest effective memory and cache footprint. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2099 | */ |
| 2100 | void sched_exec(void) |
| 2101 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2102 | int new_cpu, this_cpu = get_cpu(); |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 2103 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2104 | put_cpu(); |
Nick Piggin | 476d139 | 2005-06-25 14:57:29 -0700 | [diff] [blame] | 2105 | if (new_cpu != this_cpu) |
| 2106 | sched_migrate_task(current, new_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2107 | } |
| 2108 | |
| 2109 | /* |
| 2110 | * pull_task - move a task from a remote runqueue to the local runqueue. |
| 2111 | * Both runqueues must be locked. |
| 2112 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2113 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
| 2114 | struct rq *this_rq, int this_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2115 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2116 | deactivate_task(src_rq, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2117 | set_task_cpu(p, this_cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2118 | activate_task(this_rq, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2119 | /* |
| 2120 | * Note that idle threads have a prio of MAX_PRIO, for this test |
| 2121 | * to be always true for them. |
| 2122 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2123 | check_preempt_curr(this_rq, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2124 | } |
| 2125 | |
| 2126 | /* |
| 2127 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? |
| 2128 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 2129 | static |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2130 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2131 | struct sched_domain *sd, enum cpu_idle_type idle, |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 2132 | int *all_pinned) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2133 | { |
| 2134 | /* |
| 2135 | * We do not migrate tasks that are: |
| 2136 | * 1) running (obviously), or |
| 2137 | * 2) cannot be migrated to this CPU due to cpus_allowed, or |
| 2138 | * 3) are cache-hot on their current CPU. |
| 2139 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2140 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
| 2141 | return 0; |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2142 | *all_pinned = 0; |
| 2143 | |
| 2144 | if (task_running(rq, p)) |
| 2145 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2146 | |
| 2147 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2148 | * Aggressive migration if too many balance attempts have failed: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2149 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2150 | if (sd->nr_balance_failed > sd->cache_nice_tries) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2151 | return 1; |
| 2152 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2153 | return 1; |
| 2154 | } |
| 2155 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2156 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| 2157 | unsigned long max_nr_move, unsigned long max_load_move, |
| 2158 | struct sched_domain *sd, enum cpu_idle_type idle, |
| 2159 | int *all_pinned, unsigned long *load_moved, |
| 2160 | int this_best_prio, int best_prio, int best_prio_seen, |
| 2161 | struct rq_iterator *iterator) |
| 2162 | { |
| 2163 | int pulled = 0, pinned = 0, skip_for_load; |
| 2164 | struct task_struct *p; |
| 2165 | long rem_load_move = max_load_move; |
| 2166 | |
| 2167 | if (max_nr_move == 0 || max_load_move == 0) |
| 2168 | goto out; |
| 2169 | |
| 2170 | pinned = 1; |
| 2171 | |
| 2172 | /* |
| 2173 | * Start the load-balancing iterator: |
| 2174 | */ |
| 2175 | p = iterator->start(iterator->arg); |
| 2176 | next: |
| 2177 | if (!p) |
| 2178 | goto out; |
| 2179 | /* |
| 2180 | * To help distribute high priority tasks accross CPUs we don't |
| 2181 | * skip a task if it will be the highest priority task (i.e. smallest |
| 2182 | * prio value) on its new queue regardless of its load weight |
| 2183 | */ |
| 2184 | skip_for_load = (p->se.load.weight >> 1) > rem_load_move + |
| 2185 | SCHED_LOAD_SCALE_FUZZ; |
| 2186 | if (skip_for_load && p->prio < this_best_prio) |
| 2187 | skip_for_load = !best_prio_seen && p->prio == best_prio; |
| 2188 | if (skip_for_load || |
| 2189 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
| 2190 | |
| 2191 | best_prio_seen |= p->prio == best_prio; |
| 2192 | p = iterator->next(iterator->arg); |
| 2193 | goto next; |
| 2194 | } |
| 2195 | |
| 2196 | pull_task(busiest, p, this_rq, this_cpu); |
| 2197 | pulled++; |
| 2198 | rem_load_move -= p->se.load.weight; |
| 2199 | |
| 2200 | /* |
| 2201 | * We only want to steal up to the prescribed number of tasks |
| 2202 | * and the prescribed amount of weighted load. |
| 2203 | */ |
| 2204 | if (pulled < max_nr_move && rem_load_move > 0) { |
| 2205 | if (p->prio < this_best_prio) |
| 2206 | this_best_prio = p->prio; |
| 2207 | p = iterator->next(iterator->arg); |
| 2208 | goto next; |
| 2209 | } |
| 2210 | out: |
| 2211 | /* |
| 2212 | * Right now, this is the only place pull_task() is called, |
| 2213 | * so we can safely collect pull_task() stats here rather than |
| 2214 | * inside pull_task(). |
| 2215 | */ |
| 2216 | schedstat_add(sd, lb_gained[idle], pulled); |
| 2217 | |
| 2218 | if (all_pinned) |
| 2219 | *all_pinned = pinned; |
| 2220 | *load_moved = max_load_move - rem_load_move; |
| 2221 | return pulled; |
| 2222 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2223 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2224 | /* |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2225 | * move_tasks tries to move up to max_nr_move tasks and max_load_move weighted |
| 2226 | * load from busiest to this_rq, as part of a balancing operation within |
| 2227 | * "domain". Returns the number of tasks moved. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2228 | * |
| 2229 | * Called with both runqueues locked. |
| 2230 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2231 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2232 | unsigned long max_nr_move, unsigned long max_load_move, |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2233 | struct sched_domain *sd, enum cpu_idle_type idle, |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2234 | int *all_pinned) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2235 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2236 | struct sched_class *class = sched_class_highest; |
| 2237 | unsigned long load_moved, total_nr_moved = 0, nr_moved; |
| 2238 | long rem_load_move = max_load_move; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2239 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2240 | do { |
| 2241 | nr_moved = class->load_balance(this_rq, this_cpu, busiest, |
| 2242 | max_nr_move, (unsigned long)rem_load_move, |
| 2243 | sd, idle, all_pinned, &load_moved); |
| 2244 | total_nr_moved += nr_moved; |
| 2245 | max_nr_move -= nr_moved; |
| 2246 | rem_load_move -= load_moved; |
| 2247 | class = class->next; |
| 2248 | } while (class && max_nr_move && rem_load_move > 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2249 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2250 | return total_nr_moved; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2251 | } |
| 2252 | |
| 2253 | /* |
| 2254 | * find_busiest_group finds and returns the busiest CPU group within the |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2255 | * domain. It calculates and returns the amount of weighted load which |
| 2256 | * should be moved to restore balance via the imbalance parameter. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2257 | */ |
| 2258 | static struct sched_group * |
| 2259 | find_busiest_group(struct sched_domain *sd, int this_cpu, |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2260 | unsigned long *imbalance, enum cpu_idle_type idle, |
| 2261 | int *sd_idle, cpumask_t *cpus, int *balance) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2262 | { |
| 2263 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; |
| 2264 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; |
Siddha, Suresh B | 0c117f1 | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2265 | unsigned long max_pull; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2266 | unsigned long busiest_load_per_task, busiest_nr_running; |
| 2267 | unsigned long this_load_per_task, this_nr_running; |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 2268 | int load_idx; |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2269 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| 2270 | int power_savings_balance = 1; |
| 2271 | unsigned long leader_nr_running = 0, min_load_per_task = 0; |
| 2272 | unsigned long min_nr_running = ULONG_MAX; |
| 2273 | struct sched_group *group_min = NULL, *group_leader = NULL; |
| 2274 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2275 | |
| 2276 | max_load = this_load = total_load = total_pwr = 0; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2277 | busiest_load_per_task = busiest_nr_running = 0; |
| 2278 | this_load_per_task = this_nr_running = 0; |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2279 | if (idle == CPU_NOT_IDLE) |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 2280 | load_idx = sd->busy_idx; |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2281 | else if (idle == CPU_NEWLY_IDLE) |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 2282 | load_idx = sd->newidle_idx; |
| 2283 | else |
| 2284 | load_idx = sd->idle_idx; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2285 | |
| 2286 | do { |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2287 | unsigned long load, group_capacity; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2288 | int local_group; |
| 2289 | int i; |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2290 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2291 | unsigned long sum_nr_running, sum_weighted_load; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2292 | |
| 2293 | local_group = cpu_isset(this_cpu, group->cpumask); |
| 2294 | |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2295 | if (local_group) |
| 2296 | balance_cpu = first_cpu(group->cpumask); |
| 2297 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2298 | /* Tally up the load of all CPUs in the group */ |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2299 | sum_weighted_load = sum_nr_running = avg_load = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2300 | |
| 2301 | for_each_cpu_mask(i, group->cpumask) { |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2302 | struct rq *rq; |
| 2303 | |
| 2304 | if (!cpu_isset(i, *cpus)) |
| 2305 | continue; |
| 2306 | |
| 2307 | rq = cpu_rq(i); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2308 | |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2309 | if (*sd_idle && !idle_cpu(i)) |
| 2310 | *sd_idle = 0; |
| 2311 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2312 | /* Bias balancing toward cpus of our domain */ |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2313 | if (local_group) { |
| 2314 | if (idle_cpu(i) && !first_idle_cpu) { |
| 2315 | first_idle_cpu = 1; |
| 2316 | balance_cpu = i; |
| 2317 | } |
| 2318 | |
Nick Piggin | a200057 | 2006-02-10 01:51:02 -0800 | [diff] [blame] | 2319 | load = target_load(i, load_idx); |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2320 | } else |
Nick Piggin | a200057 | 2006-02-10 01:51:02 -0800 | [diff] [blame] | 2321 | load = source_load(i, load_idx); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2322 | |
| 2323 | avg_load += load; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2324 | sum_nr_running += rq->nr_running; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2325 | sum_weighted_load += weighted_cpuload(i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2326 | } |
| 2327 | |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2328 | /* |
| 2329 | * First idle cpu or the first cpu(busiest) in this sched group |
| 2330 | * is eligible for doing load balancing at this and above |
| 2331 | * domains. |
| 2332 | */ |
| 2333 | if (local_group && balance_cpu != this_cpu && balance) { |
| 2334 | *balance = 0; |
| 2335 | goto ret; |
| 2336 | } |
| 2337 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2338 | total_load += avg_load; |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2339 | total_pwr += group->__cpu_power; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2340 | |
| 2341 | /* Adjust by relative CPU power of the group */ |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2342 | avg_load = sg_div_cpu_power(group, |
| 2343 | avg_load * SCHED_LOAD_SCALE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2344 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2345 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2346 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2347 | if (local_group) { |
| 2348 | this_load = avg_load; |
| 2349 | this = group; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2350 | this_nr_running = sum_nr_running; |
| 2351 | this_load_per_task = sum_weighted_load; |
| 2352 | } else if (avg_load > max_load && |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2353 | sum_nr_running > group_capacity) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2354 | max_load = avg_load; |
| 2355 | busiest = group; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2356 | busiest_nr_running = sum_nr_running; |
| 2357 | busiest_load_per_task = sum_weighted_load; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2358 | } |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2359 | |
| 2360 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| 2361 | /* |
| 2362 | * Busy processors will not participate in power savings |
| 2363 | * balance. |
| 2364 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2365 | if (idle == CPU_NOT_IDLE || |
| 2366 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
| 2367 | goto group_next; |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2368 | |
| 2369 | /* |
| 2370 | * If the local group is idle or completely loaded |
| 2371 | * no need to do power savings balance at this domain |
| 2372 | */ |
| 2373 | if (local_group && (this_nr_running >= group_capacity || |
| 2374 | !this_nr_running)) |
| 2375 | power_savings_balance = 0; |
| 2376 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2377 | /* |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2378 | * If a group is already running at full capacity or idle, |
| 2379 | * don't include that group in power savings calculations |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2380 | */ |
| 2381 | if (!power_savings_balance || sum_nr_running >= group_capacity |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2382 | || !sum_nr_running) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2383 | goto group_next; |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2384 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2385 | /* |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2386 | * Calculate the group which has the least non-idle load. |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2387 | * This is the group from where we need to pick up the load |
| 2388 | * for saving power |
| 2389 | */ |
| 2390 | if ((sum_nr_running < min_nr_running) || |
| 2391 | (sum_nr_running == min_nr_running && |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2392 | first_cpu(group->cpumask) < |
| 2393 | first_cpu(group_min->cpumask))) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2394 | group_min = group; |
| 2395 | min_nr_running = sum_nr_running; |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2396 | min_load_per_task = sum_weighted_load / |
| 2397 | sum_nr_running; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2398 | } |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2399 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2400 | /* |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2401 | * Calculate the group which is almost near its |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2402 | * capacity but still has some space to pick up some load |
| 2403 | * from other group and save more power |
| 2404 | */ |
| 2405 | if (sum_nr_running <= group_capacity - 1) { |
| 2406 | if (sum_nr_running > leader_nr_running || |
| 2407 | (sum_nr_running == leader_nr_running && |
| 2408 | first_cpu(group->cpumask) > |
| 2409 | first_cpu(group_leader->cpumask))) { |
| 2410 | group_leader = group; |
| 2411 | leader_nr_running = sum_nr_running; |
| 2412 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2413 | } |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2414 | group_next: |
| 2415 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2416 | group = group->next; |
| 2417 | } while (group != sd->groups); |
| 2418 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2419 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2420 | goto out_balanced; |
| 2421 | |
| 2422 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; |
| 2423 | |
| 2424 | if (this_load >= avg_load || |
| 2425 | 100*max_load <= sd->imbalance_pct*this_load) |
| 2426 | goto out_balanced; |
| 2427 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2428 | busiest_load_per_task /= busiest_nr_running; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2429 | /* |
| 2430 | * We're trying to get all the cpus to the average_load, so we don't |
| 2431 | * want to push ourselves above the average load, nor do we wish to |
| 2432 | * reduce the max loaded cpu below the average load, as either of these |
| 2433 | * actions would just result in more rebalancing later, and ping-pong |
| 2434 | * tasks around. Thus we look for the minimum possible imbalance. |
| 2435 | * Negative imbalances (*we* are more loaded than anyone else) will |
| 2436 | * be counted as no imbalance for these purposes -- we can't fix that |
| 2437 | * by pulling tasks to us. Be careful of negative numbers as they'll |
| 2438 | * appear as very large values with unsigned longs. |
| 2439 | */ |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2440 | if (max_load <= busiest_load_per_task) |
| 2441 | goto out_balanced; |
| 2442 | |
| 2443 | /* |
| 2444 | * In the presence of smp nice balancing, certain scenarios can have |
| 2445 | * max load less than avg load(as we skip the groups at or below |
| 2446 | * its cpu_power, while calculating max_load..) |
| 2447 | */ |
| 2448 | if (max_load < avg_load) { |
| 2449 | *imbalance = 0; |
| 2450 | goto small_imbalance; |
| 2451 | } |
Siddha, Suresh B | 0c117f1 | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2452 | |
| 2453 | /* Don't want to pull so many tasks that a group would go idle */ |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2454 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
Siddha, Suresh B | 0c117f1 | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2455 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2456 | /* How much load to actually move to equalise the imbalance */ |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2457 | *imbalance = min(max_pull * busiest->__cpu_power, |
| 2458 | (avg_load - this_load) * this->__cpu_power) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2459 | / SCHED_LOAD_SCALE; |
| 2460 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2461 | /* |
| 2462 | * if *imbalance is less than the average load per runnable task |
| 2463 | * there is no gaurantee that any tasks will be moved so we'll have |
| 2464 | * a think about bumping its value to force at least one task to be |
| 2465 | * moved |
| 2466 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2467 | if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2468 | unsigned long tmp, pwr_now, pwr_move; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2469 | unsigned int imbn; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2470 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2471 | small_imbalance: |
| 2472 | pwr_move = pwr_now = 0; |
| 2473 | imbn = 2; |
| 2474 | if (this_nr_running) { |
| 2475 | this_load_per_task /= this_nr_running; |
| 2476 | if (busiest_load_per_task > this_load_per_task) |
| 2477 | imbn = 1; |
| 2478 | } else |
| 2479 | this_load_per_task = SCHED_LOAD_SCALE; |
| 2480 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2481 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
| 2482 | busiest_load_per_task * imbn) { |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2483 | *imbalance = busiest_load_per_task; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2484 | return busiest; |
| 2485 | } |
| 2486 | |
| 2487 | /* |
| 2488 | * OK, we don't have enough imbalance to justify moving tasks, |
| 2489 | * however we may be able to increase total CPU power used by |
| 2490 | * moving them. |
| 2491 | */ |
| 2492 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2493 | pwr_now += busiest->__cpu_power * |
| 2494 | min(busiest_load_per_task, max_load); |
| 2495 | pwr_now += this->__cpu_power * |
| 2496 | min(this_load_per_task, this_load); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2497 | pwr_now /= SCHED_LOAD_SCALE; |
| 2498 | |
| 2499 | /* Amount of load we'd subtract */ |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2500 | tmp = sg_div_cpu_power(busiest, |
| 2501 | busiest_load_per_task * SCHED_LOAD_SCALE); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2502 | if (max_load > tmp) |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2503 | pwr_move += busiest->__cpu_power * |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2504 | min(busiest_load_per_task, max_load - tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2505 | |
| 2506 | /* Amount of load we'd add */ |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2507 | if (max_load * busiest->__cpu_power < |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 2508 | busiest_load_per_task * SCHED_LOAD_SCALE) |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2509 | tmp = sg_div_cpu_power(this, |
| 2510 | max_load * busiest->__cpu_power); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2511 | else |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 2512 | tmp = sg_div_cpu_power(this, |
| 2513 | busiest_load_per_task * SCHED_LOAD_SCALE); |
| 2514 | pwr_move += this->__cpu_power * |
| 2515 | min(this_load_per_task, this_load + tmp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2516 | pwr_move /= SCHED_LOAD_SCALE; |
| 2517 | |
| 2518 | /* Move if we gain throughput */ |
| 2519 | if (pwr_move <= pwr_now) |
| 2520 | goto out_balanced; |
| 2521 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2522 | *imbalance = busiest_load_per_task; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2523 | } |
| 2524 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2525 | return busiest; |
| 2526 | |
| 2527 | out_balanced: |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2528 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2529 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2530 | goto ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2531 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2532 | if (this == group_leader && group_leader != group_min) { |
| 2533 | *imbalance = min_load_per_task; |
| 2534 | return group_min; |
| 2535 | } |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2536 | #endif |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2537 | ret: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2538 | *imbalance = 0; |
| 2539 | return NULL; |
| 2540 | } |
| 2541 | |
| 2542 | /* |
| 2543 | * find_busiest_queue - find the busiest runqueue among the cpus in group. |
| 2544 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2545 | static struct rq * |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2546 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2547 | unsigned long imbalance, cpumask_t *cpus) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2548 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2549 | struct rq *busiest = NULL, *rq; |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2550 | unsigned long max_load = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2551 | int i; |
| 2552 | |
| 2553 | for_each_cpu_mask(i, group->cpumask) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2554 | unsigned long wl; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2555 | |
| 2556 | if (!cpu_isset(i, *cpus)) |
| 2557 | continue; |
| 2558 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2559 | rq = cpu_rq(i); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2560 | wl = weighted_cpuload(i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2561 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2562 | if (rq->nr_running == 1 && wl > imbalance) |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2563 | continue; |
| 2564 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2565 | if (wl > max_load) { |
| 2566 | max_load = wl; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2567 | busiest = rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2568 | } |
| 2569 | } |
| 2570 | |
| 2571 | return busiest; |
| 2572 | } |
| 2573 | |
| 2574 | /* |
Nick Piggin | 77391d7 | 2005-06-25 14:57:30 -0700 | [diff] [blame] | 2575 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but |
| 2576 | * so long as it is large enough. |
| 2577 | */ |
| 2578 | #define MAX_PINNED_INTERVAL 512 |
| 2579 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2580 | static inline unsigned long minus_1_or_zero(unsigned long n) |
| 2581 | { |
| 2582 | return n > 0 ? n - 1 : 0; |
| 2583 | } |
| 2584 | |
Nick Piggin | 77391d7 | 2005-06-25 14:57:30 -0700 | [diff] [blame] | 2585 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2586 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
| 2587 | * tasks if there is an imbalance. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2588 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2589 | static int load_balance(int this_cpu, struct rq *this_rq, |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2590 | struct sched_domain *sd, enum cpu_idle_type idle, |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2591 | int *balance) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2592 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2593 | int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2594 | struct sched_group *group; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2595 | unsigned long imbalance; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2596 | struct rq *busiest; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2597 | cpumask_t cpus = CPU_MASK_ALL; |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2598 | unsigned long flags; |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2599 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2600 | /* |
| 2601 | * When power savings policy is enabled for the parent domain, idle |
| 2602 | * sibling can pick up load irrespective of busy siblings. In this case, |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2603 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2604 | * portraying it as CPU_NOT_IDLE. |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2605 | */ |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2606 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2607 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2608 | sd_idle = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2609 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2610 | schedstat_inc(sd, lb_cnt[idle]); |
| 2611 | |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2612 | redo: |
| 2613 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2614 | &cpus, balance); |
| 2615 | |
Chen, Kenneth W | 0606671 | 2006-12-10 02:20:35 -0800 | [diff] [blame] | 2616 | if (*balance == 0) |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2617 | goto out_balanced; |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2618 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2619 | if (!group) { |
| 2620 | schedstat_inc(sd, lb_nobusyg[idle]); |
| 2621 | goto out_balanced; |
| 2622 | } |
| 2623 | |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2624 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2625 | if (!busiest) { |
| 2626 | schedstat_inc(sd, lb_nobusyq[idle]); |
| 2627 | goto out_balanced; |
| 2628 | } |
| 2629 | |
Nick Piggin | db935db | 2005-06-25 14:57:11 -0700 | [diff] [blame] | 2630 | BUG_ON(busiest == this_rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2631 | |
| 2632 | schedstat_add(sd, lb_imbalance[idle], imbalance); |
| 2633 | |
| 2634 | nr_moved = 0; |
| 2635 | if (busiest->nr_running > 1) { |
| 2636 | /* |
| 2637 | * Attempt to move tasks. If find_busiest_group has found |
| 2638 | * an imbalance but busiest->nr_running <= 1, the group is |
| 2639 | * still unbalanced. nr_moved simply stays zero, so it is |
| 2640 | * correctly treated as an imbalance. |
| 2641 | */ |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2642 | local_irq_save(flags); |
Nick Piggin | e17224b | 2005-09-10 00:26:18 -0700 | [diff] [blame] | 2643 | double_rq_lock(this_rq, busiest); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2644 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2645 | minus_1_or_zero(busiest->nr_running), |
| 2646 | imbalance, sd, idle, &all_pinned); |
Nick Piggin | e17224b | 2005-09-10 00:26:18 -0700 | [diff] [blame] | 2647 | double_rq_unlock(this_rq, busiest); |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2648 | local_irq_restore(flags); |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2649 | |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2650 | /* |
| 2651 | * some other cpu did the load balance for us. |
| 2652 | */ |
| 2653 | if (nr_moved && this_cpu != smp_processor_id()) |
| 2654 | resched_cpu(this_cpu); |
| 2655 | |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2656 | /* All tasks on this runqueue were pinned by CPU affinity */ |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2657 | if (unlikely(all_pinned)) { |
| 2658 | cpu_clear(cpu_of(busiest), cpus); |
| 2659 | if (!cpus_empty(cpus)) |
| 2660 | goto redo; |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2661 | goto out_balanced; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2662 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2663 | } |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2664 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2665 | if (!nr_moved) { |
| 2666 | schedstat_inc(sd, lb_failed[idle]); |
| 2667 | sd->nr_balance_failed++; |
| 2668 | |
| 2669 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2670 | |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2671 | spin_lock_irqsave(&busiest->lock, flags); |
Siddha, Suresh B | fa3b6dd | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2672 | |
| 2673 | /* don't kick the migration_thread, if the curr |
| 2674 | * task on busiest cpu can't be moved to this_cpu |
| 2675 | */ |
| 2676 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2677 | spin_unlock_irqrestore(&busiest->lock, flags); |
Siddha, Suresh B | fa3b6dd | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2678 | all_pinned = 1; |
| 2679 | goto out_one_pinned; |
| 2680 | } |
| 2681 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2682 | if (!busiest->active_balance) { |
| 2683 | busiest->active_balance = 1; |
| 2684 | busiest->push_cpu = this_cpu; |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2685 | active_balance = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2686 | } |
Christoph Lameter | fe2eea3 | 2006-12-10 02:20:21 -0800 | [diff] [blame] | 2687 | spin_unlock_irqrestore(&busiest->lock, flags); |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2688 | if (active_balance) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2689 | wake_up_process(busiest->migration_thread); |
| 2690 | |
| 2691 | /* |
| 2692 | * We've kicked active balancing, reset the failure |
| 2693 | * counter. |
| 2694 | */ |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2695 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2696 | } |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2697 | } else |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2698 | sd->nr_balance_failed = 0; |
| 2699 | |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2700 | if (likely(!active_balance)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2701 | /* We were unbalanced, so reset the balancing interval */ |
| 2702 | sd->balance_interval = sd->min_interval; |
Nick Piggin | 8102679 | 2005-06-25 14:57:07 -0700 | [diff] [blame] | 2703 | } else { |
| 2704 | /* |
| 2705 | * If we've begun active balancing, start to back off. This |
| 2706 | * case may not be covered by the all_pinned logic if there |
| 2707 | * is only 1 task on the busy runqueue (because we don't call |
| 2708 | * move_tasks). |
| 2709 | */ |
| 2710 | if (sd->balance_interval < sd->max_interval) |
| 2711 | sd->balance_interval *= 2; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2712 | } |
| 2713 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 2714 | if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2715 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2716 | return -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2717 | return nr_moved; |
| 2718 | |
| 2719 | out_balanced: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2720 | schedstat_inc(sd, lb_balanced[idle]); |
| 2721 | |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2722 | sd->nr_balance_failed = 0; |
Siddha, Suresh B | fa3b6dd | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 2723 | |
| 2724 | out_one_pinned: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2725 | /* tune up the balancing interval */ |
Nick Piggin | 77391d7 | 2005-06-25 14:57:30 -0700 | [diff] [blame] | 2726 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
| 2727 | (sd->balance_interval < sd->max_interval)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2728 | sd->balance_interval *= 2; |
| 2729 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2730 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2731 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2732 | return -1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2733 | return 0; |
| 2734 | } |
| 2735 | |
| 2736 | /* |
| 2737 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
| 2738 | * tasks if there is an imbalance. |
| 2739 | * |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2740 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2741 | * this_rq is locked. |
| 2742 | */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2743 | static int |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2744 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2745 | { |
| 2746 | struct sched_group *group; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2747 | struct rq *busiest = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2748 | unsigned long imbalance; |
| 2749 | int nr_moved = 0; |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2750 | int sd_idle = 0; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2751 | cpumask_t cpus = CPU_MASK_ALL; |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2752 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2753 | /* |
| 2754 | * When power savings policy is enabled for the parent domain, idle |
| 2755 | * sibling can pick up load irrespective of busy siblings. In this case, |
| 2756 | * let the state of idle sibling percolate up as IDLE, instead of |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2757 | * portraying it as CPU_NOT_IDLE. |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2758 | */ |
| 2759 | if (sd->flags & SD_SHARE_CPUPOWER && |
| 2760 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2761 | sd_idle = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2762 | |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2763 | schedstat_inc(sd, lb_cnt[CPU_NEWLY_IDLE]); |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2764 | redo: |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2765 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 2766 | &sd_idle, &cpus, NULL); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2767 | if (!group) { |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2768 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2769 | goto out_balanced; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2770 | } |
| 2771 | |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2772 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2773 | &cpus); |
Nick Piggin | db935db | 2005-06-25 14:57:11 -0700 | [diff] [blame] | 2774 | if (!busiest) { |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2775 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2776 | goto out_balanced; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2777 | } |
| 2778 | |
Nick Piggin | db935db | 2005-06-25 14:57:11 -0700 | [diff] [blame] | 2779 | BUG_ON(busiest == this_rq); |
| 2780 | |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2781 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
Nick Piggin | d6d5cfa | 2005-09-10 00:26:16 -0700 | [diff] [blame] | 2782 | |
| 2783 | nr_moved = 0; |
| 2784 | if (busiest->nr_running > 1) { |
| 2785 | /* Attempt to move tasks */ |
| 2786 | double_lock_balance(this_rq, busiest); |
| 2787 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 2788 | minus_1_or_zero(busiest->nr_running), |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2789 | imbalance, sd, CPU_NEWLY_IDLE, NULL); |
Nick Piggin | d6d5cfa | 2005-09-10 00:26:16 -0700 | [diff] [blame] | 2790 | spin_unlock(&busiest->lock); |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 2791 | |
| 2792 | if (!nr_moved) { |
| 2793 | cpu_clear(cpu_of(busiest), cpus); |
| 2794 | if (!cpus_empty(cpus)) |
| 2795 | goto redo; |
| 2796 | } |
Nick Piggin | d6d5cfa | 2005-09-10 00:26:16 -0700 | [diff] [blame] | 2797 | } |
| 2798 | |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2799 | if (!nr_moved) { |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2800 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2801 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
| 2802 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2803 | return -1; |
| 2804 | } else |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2805 | sd->nr_balance_failed = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2806 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2807 | return nr_moved; |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2808 | |
| 2809 | out_balanced: |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2810 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2811 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 2812 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 2813 | return -1; |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2814 | sd->nr_balance_failed = 0; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2815 | |
Nick Piggin | 16cfb1c | 2005-06-25 14:57:08 -0700 | [diff] [blame] | 2816 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2817 | } |
| 2818 | |
| 2819 | /* |
| 2820 | * idle_balance is called by schedule() if this_cpu is about to become |
| 2821 | * idle. Attempts to pull tasks from other CPUs. |
| 2822 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2823 | static void idle_balance(int this_cpu, struct rq *this_rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2824 | { |
| 2825 | struct sched_domain *sd; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2826 | int pulled_task = -1; |
| 2827 | unsigned long next_balance = jiffies + HZ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2828 | |
| 2829 | for_each_domain(this_cpu, sd) { |
Christoph Lameter | 92c4ca5 | 2007-06-23 17:16:33 -0700 | [diff] [blame] | 2830 | unsigned long interval; |
| 2831 | |
| 2832 | if (!(sd->flags & SD_LOAD_BALANCE)) |
| 2833 | continue; |
| 2834 | |
| 2835 | if (sd->flags & SD_BALANCE_NEWIDLE) |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2836 | /* If we've pulled tasks over stop searching: */ |
Christoph Lameter | 1bd77f2 | 2006-12-10 02:20:27 -0800 | [diff] [blame] | 2837 | pulled_task = load_balance_newidle(this_cpu, |
Christoph Lameter | 92c4ca5 | 2007-06-23 17:16:33 -0700 | [diff] [blame] | 2838 | this_rq, sd); |
| 2839 | |
| 2840 | interval = msecs_to_jiffies(sd->balance_interval); |
| 2841 | if (time_after(next_balance, sd->last_balance + interval)) |
| 2842 | next_balance = sd->last_balance + interval; |
| 2843 | if (pulled_task) |
| 2844 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2845 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2846 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
Christoph Lameter | 1bd77f2 | 2006-12-10 02:20:27 -0800 | [diff] [blame] | 2847 | /* |
| 2848 | * We are going idle. next_balance may be set based on |
| 2849 | * a busy processor. So reset next_balance. |
| 2850 | */ |
| 2851 | this_rq->next_balance = next_balance; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 2852 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2853 | } |
| 2854 | |
| 2855 | /* |
| 2856 | * active_load_balance is run by migration threads. It pushes running tasks |
| 2857 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be |
| 2858 | * running on each physical CPU where possible, and avoids physical / |
| 2859 | * logical imbalances. |
| 2860 | * |
| 2861 | * Called with busiest_rq locked. |
| 2862 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2863 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2864 | { |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2865 | int target_cpu = busiest_rq->push_cpu; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 2866 | struct sched_domain *sd; |
| 2867 | struct rq *target_rq; |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2868 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2869 | /* Is there any task to move? */ |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2870 | if (busiest_rq->nr_running <= 1) |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2871 | return; |
| 2872 | |
| 2873 | target_rq = cpu_rq(target_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2874 | |
| 2875 | /* |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2876 | * This condition is "impossible", if it occurs |
| 2877 | * we need to fix it. Originally reported by |
| 2878 | * Bjorn Helgaas on a 128-cpu setup. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2879 | */ |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2880 | BUG_ON(busiest_rq == target_rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2881 | |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2882 | /* move a task from busiest_rq to target_rq */ |
| 2883 | double_lock_balance(busiest_rq, target_rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2884 | |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2885 | /* Search for an sd spanning us and the target CPU. */ |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 2886 | for_each_domain(target_cpu, sd) { |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2887 | if ((sd->flags & SD_LOAD_BALANCE) && |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2888 | cpu_isset(busiest_cpu, sd->span)) |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2889 | break; |
Chen, Kenneth W | c96d145 | 2006-06-27 02:54:28 -0700 | [diff] [blame] | 2890 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2891 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2892 | if (likely(sd)) { |
| 2893 | schedstat_inc(sd, alb_cnt); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2894 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2895 | if (move_tasks(target_rq, target_cpu, busiest_rq, 1, |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2896 | RTPRIO_TO_LOAD_WEIGHT(100), sd, CPU_IDLE, |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 2897 | NULL)) |
| 2898 | schedstat_inc(sd, alb_pushed); |
| 2899 | else |
| 2900 | schedstat_inc(sd, alb_failed); |
| 2901 | } |
Nick Piggin | 3950745 | 2005-06-25 14:57:09 -0700 | [diff] [blame] | 2902 | spin_unlock(&target_rq->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2903 | } |
| 2904 | |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2905 | #ifdef CONFIG_NO_HZ |
| 2906 | static struct { |
| 2907 | atomic_t load_balancer; |
| 2908 | cpumask_t cpu_mask; |
| 2909 | } nohz ____cacheline_aligned = { |
| 2910 | .load_balancer = ATOMIC_INIT(-1), |
| 2911 | .cpu_mask = CPU_MASK_NONE, |
| 2912 | }; |
| 2913 | |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 2914 | /* |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2915 | * This routine will try to nominate the ilb (idle load balancing) |
| 2916 | * owner among the cpus whose ticks are stopped. ilb owner will do the idle |
| 2917 | * load balancing on behalf of all those cpus. If all the cpus in the system |
| 2918 | * go into this tickless mode, then there will be no ilb owner (as there is |
| 2919 | * no need for one) and all the cpus will sleep till the next wakeup event |
| 2920 | * arrives... |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 2921 | * |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2922 | * For the ilb owner, tick is not stopped. And this tick will be used |
| 2923 | * for idle load balancing. ilb owner will still be part of |
| 2924 | * nohz.cpu_mask.. |
| 2925 | * |
| 2926 | * While stopping the tick, this cpu will become the ilb owner if there |
| 2927 | * is no other owner. And will be the owner till that cpu becomes busy |
| 2928 | * or if all cpus in the system stop their ticks at which point |
| 2929 | * there is no need for ilb owner. |
| 2930 | * |
| 2931 | * When the ilb owner becomes busy, it nominates another owner, during the |
| 2932 | * next busy scheduler_tick() |
| 2933 | */ |
| 2934 | int select_nohz_load_balancer(int stop_tick) |
| 2935 | { |
| 2936 | int cpu = smp_processor_id(); |
| 2937 | |
| 2938 | if (stop_tick) { |
| 2939 | cpu_set(cpu, nohz.cpu_mask); |
| 2940 | cpu_rq(cpu)->in_nohz_recently = 1; |
| 2941 | |
| 2942 | /* |
| 2943 | * If we are going offline and still the leader, give up! |
| 2944 | */ |
| 2945 | if (cpu_is_offline(cpu) && |
| 2946 | atomic_read(&nohz.load_balancer) == cpu) { |
| 2947 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
| 2948 | BUG(); |
| 2949 | return 0; |
| 2950 | } |
| 2951 | |
| 2952 | /* time for ilb owner also to sleep */ |
| 2953 | if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { |
| 2954 | if (atomic_read(&nohz.load_balancer) == cpu) |
| 2955 | atomic_set(&nohz.load_balancer, -1); |
| 2956 | return 0; |
| 2957 | } |
| 2958 | |
| 2959 | if (atomic_read(&nohz.load_balancer) == -1) { |
| 2960 | /* make me the ilb owner */ |
| 2961 | if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) |
| 2962 | return 1; |
| 2963 | } else if (atomic_read(&nohz.load_balancer) == cpu) |
| 2964 | return 1; |
| 2965 | } else { |
| 2966 | if (!cpu_isset(cpu, nohz.cpu_mask)) |
| 2967 | return 0; |
| 2968 | |
| 2969 | cpu_clear(cpu, nohz.cpu_mask); |
| 2970 | |
| 2971 | if (atomic_read(&nohz.load_balancer) == cpu) |
| 2972 | if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
| 2973 | BUG(); |
| 2974 | } |
| 2975 | return 0; |
| 2976 | } |
| 2977 | #endif |
| 2978 | |
| 2979 | static DEFINE_SPINLOCK(balancing); |
| 2980 | |
| 2981 | /* |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 2982 | * It checks each scheduling domain to see if it is due to be balanced, |
| 2983 | * and initiates a balancing operation if so. |
| 2984 | * |
| 2985 | * Balancing parameters are set up in arch_init_sched_domains. |
| 2986 | */ |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 2987 | static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 2988 | { |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2989 | int balance = 1; |
| 2990 | struct rq *rq = cpu_rq(cpu); |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 2991 | unsigned long interval; |
| 2992 | struct sched_domain *sd; |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2993 | /* Earliest time when we have to do rebalance again */ |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 2994 | unsigned long next_balance = jiffies + 60*HZ; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2995 | |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 2996 | for_each_domain(cpu, sd) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 2997 | if (!(sd->flags & SD_LOAD_BALANCE)) |
| 2998 | continue; |
| 2999 | |
| 3000 | interval = sd->balance_interval; |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 3001 | if (idle != CPU_IDLE) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3002 | interval *= sd->busy_factor; |
| 3003 | |
| 3004 | /* scale ms to jiffies */ |
| 3005 | interval = msecs_to_jiffies(interval); |
| 3006 | if (unlikely(!interval)) |
| 3007 | interval = 1; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3008 | if (interval > HZ*NR_CPUS/10) |
| 3009 | interval = HZ*NR_CPUS/10; |
| 3010 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3011 | |
Christoph Lameter | 08c183f | 2006-12-10 02:20:29 -0800 | [diff] [blame] | 3012 | if (sd->flags & SD_SERIALIZE) { |
| 3013 | if (!spin_trylock(&balancing)) |
| 3014 | goto out; |
| 3015 | } |
| 3016 | |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 3017 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3018 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
Siddha, Suresh B | fa3b6dd | 2005-09-10 00:26:21 -0700 | [diff] [blame] | 3019 | /* |
| 3020 | * We've pulled tasks over so either we're no |
Nick Piggin | 5969fe0 | 2005-09-10 00:26:19 -0700 | [diff] [blame] | 3021 | * longer idle, or one of our SMT siblings is |
| 3022 | * not idle. |
| 3023 | */ |
Ingo Molnar | d15bcfd | 2007-07-09 18:51:57 +0200 | [diff] [blame] | 3024 | idle = CPU_NOT_IDLE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3025 | } |
Christoph Lameter | 1bd77f2 | 2006-12-10 02:20:27 -0800 | [diff] [blame] | 3026 | sd->last_balance = jiffies; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3027 | } |
Christoph Lameter | 08c183f | 2006-12-10 02:20:29 -0800 | [diff] [blame] | 3028 | if (sd->flags & SD_SERIALIZE) |
| 3029 | spin_unlock(&balancing); |
| 3030 | out: |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 3031 | if (time_after(next_balance, sd->last_balance + interval)) |
| 3032 | next_balance = sd->last_balance + interval; |
Siddha, Suresh B | 783609c | 2006-12-10 02:20:33 -0800 | [diff] [blame] | 3033 | |
| 3034 | /* |
| 3035 | * Stop the load balance at this level. There is another |
| 3036 | * CPU in our sched group which is doing load balancing more |
| 3037 | * actively. |
| 3038 | */ |
| 3039 | if (!balance) |
| 3040 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3041 | } |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3042 | rq->next_balance = next_balance; |
| 3043 | } |
| 3044 | |
| 3045 | /* |
| 3046 | * run_rebalance_domains is triggered when needed from the scheduler tick. |
| 3047 | * In CONFIG_NO_HZ case, the idle load balance owner will do the |
| 3048 | * rebalancing for all the cpus for whom scheduler ticks are stopped. |
| 3049 | */ |
| 3050 | static void run_rebalance_domains(struct softirq_action *h) |
| 3051 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3052 | int this_cpu = smp_processor_id(); |
| 3053 | struct rq *this_rq = cpu_rq(this_cpu); |
| 3054 | enum cpu_idle_type idle = this_rq->idle_at_tick ? |
| 3055 | CPU_IDLE : CPU_NOT_IDLE; |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3056 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3057 | rebalance_domains(this_cpu, idle); |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3058 | |
| 3059 | #ifdef CONFIG_NO_HZ |
| 3060 | /* |
| 3061 | * If this cpu is the owner for idle load balancing, then do the |
| 3062 | * balancing on behalf of the other idle cpus whose ticks are |
| 3063 | * stopped. |
| 3064 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3065 | if (this_rq->idle_at_tick && |
| 3066 | atomic_read(&nohz.load_balancer) == this_cpu) { |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3067 | cpumask_t cpus = nohz.cpu_mask; |
| 3068 | struct rq *rq; |
| 3069 | int balance_cpu; |
| 3070 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3071 | cpu_clear(this_cpu, cpus); |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3072 | for_each_cpu_mask(balance_cpu, cpus) { |
| 3073 | /* |
| 3074 | * If this cpu gets work to do, stop the load balancing |
| 3075 | * work being done for other cpus. Next load |
| 3076 | * balancing owner will pick it up. |
| 3077 | */ |
| 3078 | if (need_resched()) |
| 3079 | break; |
| 3080 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3081 | rebalance_domains(balance_cpu, SCHED_IDLE); |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3082 | |
| 3083 | rq = cpu_rq(balance_cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3084 | if (time_after(this_rq->next_balance, rq->next_balance)) |
| 3085 | this_rq->next_balance = rq->next_balance; |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3086 | } |
| 3087 | } |
| 3088 | #endif |
| 3089 | } |
| 3090 | |
| 3091 | /* |
| 3092 | * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. |
| 3093 | * |
| 3094 | * In case of CONFIG_NO_HZ, this is the place where we nominate a new |
| 3095 | * idle load balancing owner or decide to stop the periodic load balancing, |
| 3096 | * if the whole system is idle. |
| 3097 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3098 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3099 | { |
Siddha, Suresh B | 46cb4b7 | 2007-05-08 00:32:51 -0700 | [diff] [blame] | 3100 | #ifdef CONFIG_NO_HZ |
| 3101 | /* |
| 3102 | * If we were in the nohz mode recently and busy at the current |
| 3103 | * scheduler tick, then check if we need to nominate new idle |
| 3104 | * load balancer. |
| 3105 | */ |
| 3106 | if (rq->in_nohz_recently && !rq->idle_at_tick) { |
| 3107 | rq->in_nohz_recently = 0; |
| 3108 | |
| 3109 | if (atomic_read(&nohz.load_balancer) == cpu) { |
| 3110 | cpu_clear(cpu, nohz.cpu_mask); |
| 3111 | atomic_set(&nohz.load_balancer, -1); |
| 3112 | } |
| 3113 | |
| 3114 | if (atomic_read(&nohz.load_balancer) == -1) { |
| 3115 | /* |
| 3116 | * simple selection for now: Nominate the |
| 3117 | * first cpu in the nohz list to be the next |
| 3118 | * ilb owner. |
| 3119 | * |
| 3120 | * TBD: Traverse the sched domains and nominate |
| 3121 | * the nearest cpu in the nohz.cpu_mask. |
| 3122 | */ |
| 3123 | int ilb = first_cpu(nohz.cpu_mask); |
| 3124 | |
| 3125 | if (ilb != NR_CPUS) |
| 3126 | resched_cpu(ilb); |
| 3127 | } |
| 3128 | } |
| 3129 | |
| 3130 | /* |
| 3131 | * If this cpu is idle and doing idle load balancing for all the |
| 3132 | * cpus with ticks stopped, is it time for that to stop? |
| 3133 | */ |
| 3134 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && |
| 3135 | cpus_weight(nohz.cpu_mask) == num_online_cpus()) { |
| 3136 | resched_cpu(cpu); |
| 3137 | return; |
| 3138 | } |
| 3139 | |
| 3140 | /* |
| 3141 | * If this cpu is idle and the idle load balancing is done by |
| 3142 | * someone else, then no need raise the SCHED_SOFTIRQ |
| 3143 | */ |
| 3144 | if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && |
| 3145 | cpu_isset(cpu, nohz.cpu_mask)) |
| 3146 | return; |
| 3147 | #endif |
| 3148 | if (time_after_eq(jiffies, rq->next_balance)) |
| 3149 | raise_softirq(SCHED_SOFTIRQ); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3150 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3151 | |
| 3152 | #else /* CONFIG_SMP */ |
| 3153 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3154 | /* |
| 3155 | * on UP we do not need to balance between CPUs: |
| 3156 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 3157 | static inline void idle_balance(int cpu, struct rq *rq) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3158 | { |
| 3159 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3160 | |
| 3161 | /* Avoid "used but not defined" warning on UP */ |
| 3162 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| 3163 | unsigned long max_nr_move, unsigned long max_load_move, |
| 3164 | struct sched_domain *sd, enum cpu_idle_type idle, |
| 3165 | int *all_pinned, unsigned long *load_moved, |
| 3166 | int this_best_prio, int best_prio, int best_prio_seen, |
| 3167 | struct rq_iterator *iterator) |
| 3168 | { |
| 3169 | *load_moved = 0; |
| 3170 | |
| 3171 | return 0; |
| 3172 | } |
| 3173 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3174 | #endif |
| 3175 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3176 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
| 3177 | |
| 3178 | EXPORT_PER_CPU_SYMBOL(kstat); |
| 3179 | |
| 3180 | /* |
Ingo Molnar | 41b86e9 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3181 | * Return p->sum_exec_runtime plus any more ns on the sched_clock |
| 3182 | * that have not yet been banked in case the task is currently running. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3183 | */ |
Ingo Molnar | 41b86e9 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3184 | unsigned long long task_sched_runtime(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3185 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3186 | unsigned long flags; |
Ingo Molnar | 41b86e9 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3187 | u64 ns, delta_exec; |
| 3188 | struct rq *rq; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3189 | |
Ingo Molnar | 41b86e9 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 3190 | rq = task_rq_lock(p, &flags); |
| 3191 | ns = p->se.sum_exec_runtime; |
| 3192 | if (rq->curr == p) { |
| 3193 | delta_exec = rq_clock(rq) - p->se.exec_start; |
| 3194 | if ((s64)delta_exec > 0) |
| 3195 | ns += delta_exec; |
| 3196 | } |
| 3197 | task_rq_unlock(rq, &flags); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3198 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3199 | return ns; |
| 3200 | } |
| 3201 | |
| 3202 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3203 | * Account user cpu time to a process. |
| 3204 | * @p: the process that the cpu time gets accounted to |
| 3205 | * @hardirq_offset: the offset to subtract from hardirq_count() |
| 3206 | * @cputime: the cpu time spent in user space since the last update |
| 3207 | */ |
| 3208 | void account_user_time(struct task_struct *p, cputime_t cputime) |
| 3209 | { |
| 3210 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| 3211 | cputime64_t tmp; |
| 3212 | |
| 3213 | p->utime = cputime_add(p->utime, cputime); |
| 3214 | |
| 3215 | /* Add user time to cpustat. */ |
| 3216 | tmp = cputime_to_cputime64(cputime); |
| 3217 | if (TASK_NICE(p) > 0) |
| 3218 | cpustat->nice = cputime64_add(cpustat->nice, tmp); |
| 3219 | else |
| 3220 | cpustat->user = cputime64_add(cpustat->user, tmp); |
| 3221 | } |
| 3222 | |
| 3223 | /* |
| 3224 | * Account system cpu time to a process. |
| 3225 | * @p: the process that the cpu time gets accounted to |
| 3226 | * @hardirq_offset: the offset to subtract from hardirq_count() |
| 3227 | * @cputime: the cpu time spent in kernel space since the last update |
| 3228 | */ |
| 3229 | void account_system_time(struct task_struct *p, int hardirq_offset, |
| 3230 | cputime_t cputime) |
| 3231 | { |
| 3232 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 3233 | struct rq *rq = this_rq(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3234 | cputime64_t tmp; |
| 3235 | |
| 3236 | p->stime = cputime_add(p->stime, cputime); |
| 3237 | |
| 3238 | /* Add system time to cpustat. */ |
| 3239 | tmp = cputime_to_cputime64(cputime); |
| 3240 | if (hardirq_count() - hardirq_offset) |
| 3241 | cpustat->irq = cputime64_add(cpustat->irq, tmp); |
| 3242 | else if (softirq_count()) |
| 3243 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); |
| 3244 | else if (p != rq->idle) |
| 3245 | cpustat->system = cputime64_add(cpustat->system, tmp); |
| 3246 | else if (atomic_read(&rq->nr_iowait) > 0) |
| 3247 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
| 3248 | else |
| 3249 | cpustat->idle = cputime64_add(cpustat->idle, tmp); |
| 3250 | /* Account for system time used */ |
| 3251 | acct_update_integrals(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3252 | } |
| 3253 | |
| 3254 | /* |
| 3255 | * Account for involuntary wait time. |
| 3256 | * @p: the process from which the cpu time has been stolen |
| 3257 | * @steal: the cpu time spent in involuntary wait |
| 3258 | */ |
| 3259 | void account_steal_time(struct task_struct *p, cputime_t steal) |
| 3260 | { |
| 3261 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| 3262 | cputime64_t tmp = cputime_to_cputime64(steal); |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 3263 | struct rq *rq = this_rq(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3264 | |
| 3265 | if (p == rq->idle) { |
| 3266 | p->stime = cputime_add(p->stime, steal); |
| 3267 | if (atomic_read(&rq->nr_iowait) > 0) |
| 3268 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
| 3269 | else |
| 3270 | cpustat->idle = cputime64_add(cpustat->idle, tmp); |
| 3271 | } else |
| 3272 | cpustat->steal = cputime64_add(cpustat->steal, tmp); |
| 3273 | } |
| 3274 | |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 3275 | /* |
| 3276 | * This function gets called by the timer code, with HZ frequency. |
| 3277 | * We call it with interrupts disabled. |
| 3278 | * |
| 3279 | * It also gets called by the fork code, when changing the parent's |
| 3280 | * timeslices. |
| 3281 | */ |
| 3282 | void scheduler_tick(void) |
| 3283 | { |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 3284 | int cpu = smp_processor_id(); |
| 3285 | struct rq *rq = cpu_rq(cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3286 | struct task_struct *curr = rq->curr; |
Christoph Lameter | 7835b98 | 2006-12-10 02:20:22 -0800 | [diff] [blame] | 3287 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3288 | spin_lock(&rq->lock); |
| 3289 | if (curr != rq->idle) /* FIXME: needed? */ |
| 3290 | curr->sched_class->task_tick(rq, curr); |
| 3291 | update_cpu_load(rq); |
| 3292 | spin_unlock(&rq->lock); |
| 3293 | |
Christoph Lameter | e418e1c | 2006-12-10 02:20:23 -0800 | [diff] [blame] | 3294 | #ifdef CONFIG_SMP |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3295 | rq->idle_at_tick = idle_cpu(cpu); |
| 3296 | trigger_load_balance(rq, cpu); |
Christoph Lameter | e418e1c | 2006-12-10 02:20:23 -0800 | [diff] [blame] | 3297 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3298 | } |
| 3299 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3300 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
| 3301 | |
| 3302 | void fastcall add_preempt_count(int val) |
| 3303 | { |
| 3304 | /* |
| 3305 | * Underflow? |
| 3306 | */ |
Ingo Molnar | 9a11b49a | 2006-07-03 00:24:33 -0700 | [diff] [blame] | 3307 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
| 3308 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3309 | preempt_count() += val; |
| 3310 | /* |
| 3311 | * Spinlock count overflowing soon? |
| 3312 | */ |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 3313 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
| 3314 | PREEMPT_MASK - 10); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3315 | } |
| 3316 | EXPORT_SYMBOL(add_preempt_count); |
| 3317 | |
| 3318 | void fastcall sub_preempt_count(int val) |
| 3319 | { |
| 3320 | /* |
| 3321 | * Underflow? |
| 3322 | */ |
Ingo Molnar | 9a11b49a | 2006-07-03 00:24:33 -0700 | [diff] [blame] | 3323 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
| 3324 | return; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3325 | /* |
| 3326 | * Is the spinlock portion underflowing? |
| 3327 | */ |
Ingo Molnar | 9a11b49a | 2006-07-03 00:24:33 -0700 | [diff] [blame] | 3328 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
| 3329 | !(preempt_count() & PREEMPT_MASK))) |
| 3330 | return; |
| 3331 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3332 | preempt_count() -= val; |
| 3333 | } |
| 3334 | EXPORT_SYMBOL(sub_preempt_count); |
| 3335 | |
| 3336 | #endif |
| 3337 | |
| 3338 | /* |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3339 | * Print scheduling while atomic bug: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3340 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3341 | static noinline void __schedule_bug(struct task_struct *prev) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3342 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3343 | printk(KERN_ERR "BUG: scheduling while atomic: %s/0x%08x/%d\n", |
| 3344 | prev->comm, preempt_count(), prev->pid); |
| 3345 | debug_show_held_locks(prev); |
| 3346 | if (irqs_disabled()) |
| 3347 | print_irqtrace_events(prev); |
| 3348 | dump_stack(); |
| 3349 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3350 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3351 | /* |
| 3352 | * Various schedule()-time debugging checks and statistics: |
| 3353 | */ |
| 3354 | static inline void schedule_debug(struct task_struct *prev) |
| 3355 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3356 | /* |
| 3357 | * Test if we are atomic. Since do_exit() needs to call into |
| 3358 | * schedule() atomically, we ignore that path for now. |
| 3359 | * Otherwise, whine if we are scheduling when we should not be. |
| 3360 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3361 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
| 3362 | __schedule_bug(prev); |
| 3363 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3364 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
| 3365 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3366 | schedstat_inc(this_rq(), sched_cnt); |
| 3367 | } |
| 3368 | |
| 3369 | /* |
| 3370 | * Pick up the highest-prio task: |
| 3371 | */ |
| 3372 | static inline struct task_struct * |
| 3373 | pick_next_task(struct rq *rq, struct task_struct *prev, u64 now) |
| 3374 | { |
| 3375 | struct sched_class *class; |
| 3376 | struct task_struct *p; |
| 3377 | |
| 3378 | /* |
| 3379 | * Optimization: we know that if all tasks are in |
| 3380 | * the fair class we can call that function directly: |
| 3381 | */ |
| 3382 | if (likely(rq->nr_running == rq->cfs.nr_running)) { |
| 3383 | p = fair_sched_class.pick_next_task(rq, now); |
| 3384 | if (likely(p)) |
| 3385 | return p; |
| 3386 | } |
| 3387 | |
| 3388 | class = sched_class_highest; |
| 3389 | for ( ; ; ) { |
| 3390 | p = class->pick_next_task(rq, now); |
| 3391 | if (p) |
| 3392 | return p; |
| 3393 | /* |
| 3394 | * Will never be NULL as the idle class always |
| 3395 | * returns a non-NULL p: |
| 3396 | */ |
| 3397 | class = class->next; |
| 3398 | } |
| 3399 | } |
| 3400 | |
| 3401 | /* |
| 3402 | * schedule() is the main scheduler function. |
| 3403 | */ |
| 3404 | asmlinkage void __sched schedule(void) |
| 3405 | { |
| 3406 | struct task_struct *prev, *next; |
| 3407 | long *switch_count; |
| 3408 | struct rq *rq; |
| 3409 | u64 now; |
| 3410 | int cpu; |
| 3411 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3412 | need_resched: |
| 3413 | preempt_disable(); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3414 | cpu = smp_processor_id(); |
| 3415 | rq = cpu_rq(cpu); |
| 3416 | rcu_qsctr_inc(cpu); |
| 3417 | prev = rq->curr; |
| 3418 | switch_count = &prev->nivcsw; |
| 3419 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3420 | release_kernel_lock(prev); |
| 3421 | need_resched_nonpreemptible: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3422 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3423 | schedule_debug(prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3424 | |
| 3425 | spin_lock_irq(&rq->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3426 | clear_tsk_need_resched(prev); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3427 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3428 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
| 3429 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
| 3430 | unlikely(signal_pending(prev)))) { |
| 3431 | prev->state = TASK_RUNNING; |
| 3432 | } else { |
| 3433 | deactivate_task(rq, prev, 1); |
| 3434 | } |
| 3435 | switch_count = &prev->nvcsw; |
| 3436 | } |
| 3437 | |
| 3438 | if (unlikely(!rq->nr_running)) |
| 3439 | idle_balance(cpu, rq); |
| 3440 | |
| 3441 | now = __rq_clock(rq); |
| 3442 | prev->sched_class->put_prev_task(rq, prev, now); |
| 3443 | next = pick_next_task(rq, prev, now); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3444 | |
| 3445 | sched_info_switch(prev, next); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3446 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3447 | if (likely(prev != next)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3448 | rq->nr_switches++; |
| 3449 | rq->curr = next; |
| 3450 | ++*switch_count; |
| 3451 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3452 | context_switch(rq, prev, next); /* unlocks the rq */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3453 | } else |
| 3454 | spin_unlock_irq(&rq->lock); |
| 3455 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3456 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
| 3457 | cpu = smp_processor_id(); |
| 3458 | rq = cpu_rq(cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3459 | goto need_resched_nonpreemptible; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3460 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3461 | preempt_enable_no_resched(); |
| 3462 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
| 3463 | goto need_resched; |
| 3464 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3465 | EXPORT_SYMBOL(schedule); |
| 3466 | |
| 3467 | #ifdef CONFIG_PREEMPT |
| 3468 | /* |
Andreas Mohr | 2ed6e34 | 2006-07-10 04:43:52 -0700 | [diff] [blame] | 3469 | * this is the entry point to schedule() from in-kernel preemption |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3470 | * off of preempt_enable. Kernel preemptions off return from interrupt |
| 3471 | * occur there and call schedule directly. |
| 3472 | */ |
| 3473 | asmlinkage void __sched preempt_schedule(void) |
| 3474 | { |
| 3475 | struct thread_info *ti = current_thread_info(); |
| 3476 | #ifdef CONFIG_PREEMPT_BKL |
| 3477 | struct task_struct *task = current; |
| 3478 | int saved_lock_depth; |
| 3479 | #endif |
| 3480 | /* |
| 3481 | * If there is a non-zero preempt_count or interrupts are disabled, |
| 3482 | * we do not want to preempt the current task. Just return.. |
| 3483 | */ |
Nick Piggin | beed33a | 2006-10-11 01:21:52 -0700 | [diff] [blame] | 3484 | if (likely(ti->preempt_count || irqs_disabled())) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3485 | return; |
| 3486 | |
| 3487 | need_resched: |
| 3488 | add_preempt_count(PREEMPT_ACTIVE); |
| 3489 | /* |
| 3490 | * We keep the big kernel semaphore locked, but we |
| 3491 | * clear ->lock_depth so that schedule() doesnt |
| 3492 | * auto-release the semaphore: |
| 3493 | */ |
| 3494 | #ifdef CONFIG_PREEMPT_BKL |
| 3495 | saved_lock_depth = task->lock_depth; |
| 3496 | task->lock_depth = -1; |
| 3497 | #endif |
| 3498 | schedule(); |
| 3499 | #ifdef CONFIG_PREEMPT_BKL |
| 3500 | task->lock_depth = saved_lock_depth; |
| 3501 | #endif |
| 3502 | sub_preempt_count(PREEMPT_ACTIVE); |
| 3503 | |
| 3504 | /* we could miss a preemption opportunity between schedule and now */ |
| 3505 | barrier(); |
| 3506 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
| 3507 | goto need_resched; |
| 3508 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3509 | EXPORT_SYMBOL(preempt_schedule); |
| 3510 | |
| 3511 | /* |
Andreas Mohr | 2ed6e34 | 2006-07-10 04:43:52 -0700 | [diff] [blame] | 3512 | * this is the entry point to schedule() from kernel preemption |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3513 | * off of irq context. |
| 3514 | * Note, that this is called and return with irqs disabled. This will |
| 3515 | * protect us against recursive calling from irq. |
| 3516 | */ |
| 3517 | asmlinkage void __sched preempt_schedule_irq(void) |
| 3518 | { |
| 3519 | struct thread_info *ti = current_thread_info(); |
| 3520 | #ifdef CONFIG_PREEMPT_BKL |
| 3521 | struct task_struct *task = current; |
| 3522 | int saved_lock_depth; |
| 3523 | #endif |
Andreas Mohr | 2ed6e34 | 2006-07-10 04:43:52 -0700 | [diff] [blame] | 3524 | /* Catch callers which need to be fixed */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3525 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
| 3526 | |
| 3527 | need_resched: |
| 3528 | add_preempt_count(PREEMPT_ACTIVE); |
| 3529 | /* |
| 3530 | * We keep the big kernel semaphore locked, but we |
| 3531 | * clear ->lock_depth so that schedule() doesnt |
| 3532 | * auto-release the semaphore: |
| 3533 | */ |
| 3534 | #ifdef CONFIG_PREEMPT_BKL |
| 3535 | saved_lock_depth = task->lock_depth; |
| 3536 | task->lock_depth = -1; |
| 3537 | #endif |
| 3538 | local_irq_enable(); |
| 3539 | schedule(); |
| 3540 | local_irq_disable(); |
| 3541 | #ifdef CONFIG_PREEMPT_BKL |
| 3542 | task->lock_depth = saved_lock_depth; |
| 3543 | #endif |
| 3544 | sub_preempt_count(PREEMPT_ACTIVE); |
| 3545 | |
| 3546 | /* we could miss a preemption opportunity between schedule and now */ |
| 3547 | barrier(); |
| 3548 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
| 3549 | goto need_resched; |
| 3550 | } |
| 3551 | |
| 3552 | #endif /* CONFIG_PREEMPT */ |
| 3553 | |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 3554 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
| 3555 | void *key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3556 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3557 | return try_to_wake_up(curr->private, mode, sync); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3558 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3559 | EXPORT_SYMBOL(default_wake_function); |
| 3560 | |
| 3561 | /* |
| 3562 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
| 3563 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
| 3564 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
| 3565 | * |
| 3566 | * There are circumstances in which we can try to wake a task which has already |
| 3567 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
| 3568 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
| 3569 | */ |
| 3570 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
| 3571 | int nr_exclusive, int sync, void *key) |
| 3572 | { |
| 3573 | struct list_head *tmp, *next; |
| 3574 | |
| 3575 | list_for_each_safe(tmp, next, &q->task_list) { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3576 | wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); |
| 3577 | unsigned flags = curr->flags; |
| 3578 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3579 | if (curr->func(curr, mode, sync, key) && |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3580 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3581 | break; |
| 3582 | } |
| 3583 | } |
| 3584 | |
| 3585 | /** |
| 3586 | * __wake_up - wake up threads blocked on a waitqueue. |
| 3587 | * @q: the waitqueue |
| 3588 | * @mode: which threads |
| 3589 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 3590 | * @key: is directly passed to the wakeup function |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3591 | */ |
| 3592 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 3593 | int nr_exclusive, void *key) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3594 | { |
| 3595 | unsigned long flags; |
| 3596 | |
| 3597 | spin_lock_irqsave(&q->lock, flags); |
| 3598 | __wake_up_common(q, mode, nr_exclusive, 0, key); |
| 3599 | spin_unlock_irqrestore(&q->lock, flags); |
| 3600 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3601 | EXPORT_SYMBOL(__wake_up); |
| 3602 | |
| 3603 | /* |
| 3604 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
| 3605 | */ |
| 3606 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) |
| 3607 | { |
| 3608 | __wake_up_common(q, mode, 1, 0, NULL); |
| 3609 | } |
| 3610 | |
| 3611 | /** |
Martin Waitz | 67be2dd | 2005-05-01 08:59:26 -0700 | [diff] [blame] | 3612 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3613 | * @q: the waitqueue |
| 3614 | * @mode: which threads |
| 3615 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
| 3616 | * |
| 3617 | * The sync wakeup differs that the waker knows that it will schedule |
| 3618 | * away soon, so while the target thread will be woken up, it will not |
| 3619 | * be migrated to another CPU - ie. the two threads are 'synchronized' |
| 3620 | * with each other. This can prevent needless bouncing between CPUs. |
| 3621 | * |
| 3622 | * On UP it can prevent extra preemption. |
| 3623 | */ |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 3624 | void fastcall |
| 3625 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3626 | { |
| 3627 | unsigned long flags; |
| 3628 | int sync = 1; |
| 3629 | |
| 3630 | if (unlikely(!q)) |
| 3631 | return; |
| 3632 | |
| 3633 | if (unlikely(!nr_exclusive)) |
| 3634 | sync = 0; |
| 3635 | |
| 3636 | spin_lock_irqsave(&q->lock, flags); |
| 3637 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); |
| 3638 | spin_unlock_irqrestore(&q->lock, flags); |
| 3639 | } |
| 3640 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
| 3641 | |
| 3642 | void fastcall complete(struct completion *x) |
| 3643 | { |
| 3644 | unsigned long flags; |
| 3645 | |
| 3646 | spin_lock_irqsave(&x->wait.lock, flags); |
| 3647 | x->done++; |
| 3648 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, |
| 3649 | 1, 0, NULL); |
| 3650 | spin_unlock_irqrestore(&x->wait.lock, flags); |
| 3651 | } |
| 3652 | EXPORT_SYMBOL(complete); |
| 3653 | |
| 3654 | void fastcall complete_all(struct completion *x) |
| 3655 | { |
| 3656 | unsigned long flags; |
| 3657 | |
| 3658 | spin_lock_irqsave(&x->wait.lock, flags); |
| 3659 | x->done += UINT_MAX/2; |
| 3660 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, |
| 3661 | 0, 0, NULL); |
| 3662 | spin_unlock_irqrestore(&x->wait.lock, flags); |
| 3663 | } |
| 3664 | EXPORT_SYMBOL(complete_all); |
| 3665 | |
| 3666 | void fastcall __sched wait_for_completion(struct completion *x) |
| 3667 | { |
| 3668 | might_sleep(); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3669 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3670 | spin_lock_irq(&x->wait.lock); |
| 3671 | if (!x->done) { |
| 3672 | DECLARE_WAITQUEUE(wait, current); |
| 3673 | |
| 3674 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
| 3675 | __add_wait_queue_tail(&x->wait, &wait); |
| 3676 | do { |
| 3677 | __set_current_state(TASK_UNINTERRUPTIBLE); |
| 3678 | spin_unlock_irq(&x->wait.lock); |
| 3679 | schedule(); |
| 3680 | spin_lock_irq(&x->wait.lock); |
| 3681 | } while (!x->done); |
| 3682 | __remove_wait_queue(&x->wait, &wait); |
| 3683 | } |
| 3684 | x->done--; |
| 3685 | spin_unlock_irq(&x->wait.lock); |
| 3686 | } |
| 3687 | EXPORT_SYMBOL(wait_for_completion); |
| 3688 | |
| 3689 | unsigned long fastcall __sched |
| 3690 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
| 3691 | { |
| 3692 | might_sleep(); |
| 3693 | |
| 3694 | spin_lock_irq(&x->wait.lock); |
| 3695 | if (!x->done) { |
| 3696 | DECLARE_WAITQUEUE(wait, current); |
| 3697 | |
| 3698 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
| 3699 | __add_wait_queue_tail(&x->wait, &wait); |
| 3700 | do { |
| 3701 | __set_current_state(TASK_UNINTERRUPTIBLE); |
| 3702 | spin_unlock_irq(&x->wait.lock); |
| 3703 | timeout = schedule_timeout(timeout); |
| 3704 | spin_lock_irq(&x->wait.lock); |
| 3705 | if (!timeout) { |
| 3706 | __remove_wait_queue(&x->wait, &wait); |
| 3707 | goto out; |
| 3708 | } |
| 3709 | } while (!x->done); |
| 3710 | __remove_wait_queue(&x->wait, &wait); |
| 3711 | } |
| 3712 | x->done--; |
| 3713 | out: |
| 3714 | spin_unlock_irq(&x->wait.lock); |
| 3715 | return timeout; |
| 3716 | } |
| 3717 | EXPORT_SYMBOL(wait_for_completion_timeout); |
| 3718 | |
| 3719 | int fastcall __sched wait_for_completion_interruptible(struct completion *x) |
| 3720 | { |
| 3721 | int ret = 0; |
| 3722 | |
| 3723 | might_sleep(); |
| 3724 | |
| 3725 | spin_lock_irq(&x->wait.lock); |
| 3726 | if (!x->done) { |
| 3727 | DECLARE_WAITQUEUE(wait, current); |
| 3728 | |
| 3729 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
| 3730 | __add_wait_queue_tail(&x->wait, &wait); |
| 3731 | do { |
| 3732 | if (signal_pending(current)) { |
| 3733 | ret = -ERESTARTSYS; |
| 3734 | __remove_wait_queue(&x->wait, &wait); |
| 3735 | goto out; |
| 3736 | } |
| 3737 | __set_current_state(TASK_INTERRUPTIBLE); |
| 3738 | spin_unlock_irq(&x->wait.lock); |
| 3739 | schedule(); |
| 3740 | spin_lock_irq(&x->wait.lock); |
| 3741 | } while (!x->done); |
| 3742 | __remove_wait_queue(&x->wait, &wait); |
| 3743 | } |
| 3744 | x->done--; |
| 3745 | out: |
| 3746 | spin_unlock_irq(&x->wait.lock); |
| 3747 | |
| 3748 | return ret; |
| 3749 | } |
| 3750 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
| 3751 | |
| 3752 | unsigned long fastcall __sched |
| 3753 | wait_for_completion_interruptible_timeout(struct completion *x, |
| 3754 | unsigned long timeout) |
| 3755 | { |
| 3756 | might_sleep(); |
| 3757 | |
| 3758 | spin_lock_irq(&x->wait.lock); |
| 3759 | if (!x->done) { |
| 3760 | DECLARE_WAITQUEUE(wait, current); |
| 3761 | |
| 3762 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
| 3763 | __add_wait_queue_tail(&x->wait, &wait); |
| 3764 | do { |
| 3765 | if (signal_pending(current)) { |
| 3766 | timeout = -ERESTARTSYS; |
| 3767 | __remove_wait_queue(&x->wait, &wait); |
| 3768 | goto out; |
| 3769 | } |
| 3770 | __set_current_state(TASK_INTERRUPTIBLE); |
| 3771 | spin_unlock_irq(&x->wait.lock); |
| 3772 | timeout = schedule_timeout(timeout); |
| 3773 | spin_lock_irq(&x->wait.lock); |
| 3774 | if (!timeout) { |
| 3775 | __remove_wait_queue(&x->wait, &wait); |
| 3776 | goto out; |
| 3777 | } |
| 3778 | } while (!x->done); |
| 3779 | __remove_wait_queue(&x->wait, &wait); |
| 3780 | } |
| 3781 | x->done--; |
| 3782 | out: |
| 3783 | spin_unlock_irq(&x->wait.lock); |
| 3784 | return timeout; |
| 3785 | } |
| 3786 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
| 3787 | |
| 3788 | |
| 3789 | #define SLEEP_ON_VAR \ |
| 3790 | unsigned long flags; \ |
| 3791 | wait_queue_t wait; \ |
| 3792 | init_waitqueue_entry(&wait, current); |
| 3793 | |
| 3794 | #define SLEEP_ON_HEAD \ |
| 3795 | spin_lock_irqsave(&q->lock,flags); \ |
| 3796 | __add_wait_queue(q, &wait); \ |
| 3797 | spin_unlock(&q->lock); |
| 3798 | |
| 3799 | #define SLEEP_ON_TAIL \ |
| 3800 | spin_lock_irq(&q->lock); \ |
| 3801 | __remove_wait_queue(q, &wait); \ |
| 3802 | spin_unlock_irqrestore(&q->lock, flags); |
| 3803 | |
| 3804 | void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) |
| 3805 | { |
| 3806 | SLEEP_ON_VAR |
| 3807 | |
| 3808 | current->state = TASK_INTERRUPTIBLE; |
| 3809 | |
| 3810 | SLEEP_ON_HEAD |
| 3811 | schedule(); |
| 3812 | SLEEP_ON_TAIL |
| 3813 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3814 | EXPORT_SYMBOL(interruptible_sleep_on); |
| 3815 | |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 3816 | long fastcall __sched |
| 3817 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3818 | { |
| 3819 | SLEEP_ON_VAR |
| 3820 | |
| 3821 | current->state = TASK_INTERRUPTIBLE; |
| 3822 | |
| 3823 | SLEEP_ON_HEAD |
| 3824 | timeout = schedule_timeout(timeout); |
| 3825 | SLEEP_ON_TAIL |
| 3826 | |
| 3827 | return timeout; |
| 3828 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3829 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
| 3830 | |
| 3831 | void fastcall __sched sleep_on(wait_queue_head_t *q) |
| 3832 | { |
| 3833 | SLEEP_ON_VAR |
| 3834 | |
| 3835 | current->state = TASK_UNINTERRUPTIBLE; |
| 3836 | |
| 3837 | SLEEP_ON_HEAD |
| 3838 | schedule(); |
| 3839 | SLEEP_ON_TAIL |
| 3840 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3841 | EXPORT_SYMBOL(sleep_on); |
| 3842 | |
| 3843 | long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
| 3844 | { |
| 3845 | SLEEP_ON_VAR |
| 3846 | |
| 3847 | current->state = TASK_UNINTERRUPTIBLE; |
| 3848 | |
| 3849 | SLEEP_ON_HEAD |
| 3850 | timeout = schedule_timeout(timeout); |
| 3851 | SLEEP_ON_TAIL |
| 3852 | |
| 3853 | return timeout; |
| 3854 | } |
| 3855 | |
| 3856 | EXPORT_SYMBOL(sleep_on_timeout); |
| 3857 | |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3858 | #ifdef CONFIG_RT_MUTEXES |
| 3859 | |
| 3860 | /* |
| 3861 | * rt_mutex_setprio - set the current priority of a task |
| 3862 | * @p: task |
| 3863 | * @prio: prio value (kernel-internal form) |
| 3864 | * |
| 3865 | * This function changes the 'effective' priority of a task. It does |
| 3866 | * not touch ->normal_prio like __setscheduler(). |
| 3867 | * |
| 3868 | * Used by the rt_mutex code to implement priority inheritance logic. |
| 3869 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 3870 | void rt_mutex_setprio(struct task_struct *p, int prio) |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3871 | { |
| 3872 | unsigned long flags; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3873 | int oldprio, on_rq; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 3874 | struct rq *rq; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3875 | u64 now; |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3876 | |
| 3877 | BUG_ON(prio < 0 || prio > MAX_PRIO); |
| 3878 | |
| 3879 | rq = task_rq_lock(p, &flags); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3880 | now = rq_clock(rq); |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3881 | |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 3882 | oldprio = p->prio; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3883 | on_rq = p->se.on_rq; |
| 3884 | if (on_rq) |
| 3885 | dequeue_task(rq, p, 0, now); |
| 3886 | |
| 3887 | if (rt_prio(prio)) |
| 3888 | p->sched_class = &rt_sched_class; |
| 3889 | else |
| 3890 | p->sched_class = &fair_sched_class; |
| 3891 | |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3892 | p->prio = prio; |
| 3893 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3894 | if (on_rq) { |
| 3895 | enqueue_task(rq, p, 0, now); |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3896 | /* |
| 3897 | * Reschedule if we are currently running on this runqueue and |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 3898 | * our priority decreased, or if we are not currently running on |
| 3899 | * this runqueue and our priority is higher than the current's |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3900 | */ |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 3901 | if (task_running(rq, p)) { |
| 3902 | if (p->prio > oldprio) |
| 3903 | resched_task(rq->curr); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3904 | } else { |
| 3905 | check_preempt_curr(rq, p); |
| 3906 | } |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3907 | } |
| 3908 | task_rq_unlock(rq, &flags); |
| 3909 | } |
| 3910 | |
| 3911 | #endif |
| 3912 | |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 3913 | void set_user_nice(struct task_struct *p, long nice) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3914 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3915 | int old_prio, delta, on_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3916 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 3917 | struct rq *rq; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3918 | u64 now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3919 | |
| 3920 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
| 3921 | return; |
| 3922 | /* |
| 3923 | * We have to be careful, if called from sys_setpriority(), |
| 3924 | * the task might be in the middle of scheduling on another CPU. |
| 3925 | */ |
| 3926 | rq = task_rq_lock(p, &flags); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3927 | now = rq_clock(rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3928 | /* |
| 3929 | * The RT priorities are set via sched_setscheduler(), but we still |
| 3930 | * allow the 'normal' nice value to be set - but as expected |
| 3931 | * it wont have any effect on scheduling until the task is |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3932 | * SCHED_FIFO/SCHED_RR: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3933 | */ |
Ingo Molnar | e05606d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3934 | if (task_has_rt_policy(p)) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3935 | p->static_prio = NICE_TO_PRIO(nice); |
| 3936 | goto out_unlock; |
| 3937 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3938 | on_rq = p->se.on_rq; |
| 3939 | if (on_rq) { |
| 3940 | dequeue_task(rq, p, 0, now); |
| 3941 | dec_load(rq, p, now); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 3942 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3943 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3944 | p->static_prio = NICE_TO_PRIO(nice); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 3945 | set_load_weight(p); |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 3946 | old_prio = p->prio; |
| 3947 | p->prio = effective_prio(p); |
| 3948 | delta = p->prio - old_prio; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3949 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 3950 | if (on_rq) { |
| 3951 | enqueue_task(rq, p, 0, now); |
| 3952 | inc_load(rq, p, now); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3953 | /* |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 3954 | * If the task increased its priority or is running and |
| 3955 | * lowered its priority, then reschedule its CPU: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3956 | */ |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 3957 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3958 | resched_task(rq->curr); |
| 3959 | } |
| 3960 | out_unlock: |
| 3961 | task_rq_unlock(rq, &flags); |
| 3962 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3963 | EXPORT_SYMBOL(set_user_nice); |
| 3964 | |
Matt Mackall | e43379f | 2005-05-01 08:59:00 -0700 | [diff] [blame] | 3965 | /* |
| 3966 | * can_nice - check if a task can reduce its nice value |
| 3967 | * @p: task |
| 3968 | * @nice: nice value |
| 3969 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 3970 | int can_nice(const struct task_struct *p, const int nice) |
Matt Mackall | e43379f | 2005-05-01 08:59:00 -0700 | [diff] [blame] | 3971 | { |
Matt Mackall | 024f474 | 2005-08-18 11:24:19 -0700 | [diff] [blame] | 3972 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
| 3973 | int nice_rlim = 20 - nice; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3974 | |
Matt Mackall | e43379f | 2005-05-01 08:59:00 -0700 | [diff] [blame] | 3975 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
| 3976 | capable(CAP_SYS_NICE)); |
| 3977 | } |
| 3978 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3979 | #ifdef __ARCH_WANT_SYS_NICE |
| 3980 | |
| 3981 | /* |
| 3982 | * sys_nice - change the priority of the current process. |
| 3983 | * @increment: priority increment |
| 3984 | * |
| 3985 | * sys_setpriority is a more generic, but much slower function that |
| 3986 | * does similar things. |
| 3987 | */ |
| 3988 | asmlinkage long sys_nice(int increment) |
| 3989 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 3990 | long nice, retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3991 | |
| 3992 | /* |
| 3993 | * Setpriority might change our priority at the same moment. |
| 3994 | * We don't have to worry. Conceptually one call occurs first |
| 3995 | * and we have a single winner. |
| 3996 | */ |
Matt Mackall | e43379f | 2005-05-01 08:59:00 -0700 | [diff] [blame] | 3997 | if (increment < -40) |
| 3998 | increment = -40; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 3999 | if (increment > 40) |
| 4000 | increment = 40; |
| 4001 | |
| 4002 | nice = PRIO_TO_NICE(current->static_prio) + increment; |
| 4003 | if (nice < -20) |
| 4004 | nice = -20; |
| 4005 | if (nice > 19) |
| 4006 | nice = 19; |
| 4007 | |
Matt Mackall | e43379f | 2005-05-01 08:59:00 -0700 | [diff] [blame] | 4008 | if (increment < 0 && !can_nice(current, nice)) |
| 4009 | return -EPERM; |
| 4010 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4011 | retval = security_task_setnice(current, nice); |
| 4012 | if (retval) |
| 4013 | return retval; |
| 4014 | |
| 4015 | set_user_nice(current, nice); |
| 4016 | return 0; |
| 4017 | } |
| 4018 | |
| 4019 | #endif |
| 4020 | |
| 4021 | /** |
| 4022 | * task_prio - return the priority value of a given task. |
| 4023 | * @p: the task in question. |
| 4024 | * |
| 4025 | * This is the priority value as seen by users in /proc. |
| 4026 | * RT tasks are offset by -200. Normal tasks are centered |
| 4027 | * around 0, value goes from -16 to +15. |
| 4028 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4029 | int task_prio(const struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4030 | { |
| 4031 | return p->prio - MAX_RT_PRIO; |
| 4032 | } |
| 4033 | |
| 4034 | /** |
| 4035 | * task_nice - return the nice value of a given task. |
| 4036 | * @p: the task in question. |
| 4037 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4038 | int task_nice(const struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4039 | { |
| 4040 | return TASK_NICE(p); |
| 4041 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4042 | EXPORT_SYMBOL_GPL(task_nice); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4043 | |
| 4044 | /** |
| 4045 | * idle_cpu - is a given cpu idle currently? |
| 4046 | * @cpu: the processor in question. |
| 4047 | */ |
| 4048 | int idle_cpu(int cpu) |
| 4049 | { |
| 4050 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; |
| 4051 | } |
| 4052 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4053 | /** |
| 4054 | * idle_task - return the idle task for a given cpu. |
| 4055 | * @cpu: the processor in question. |
| 4056 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4057 | struct task_struct *idle_task(int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4058 | { |
| 4059 | return cpu_rq(cpu)->idle; |
| 4060 | } |
| 4061 | |
| 4062 | /** |
| 4063 | * find_process_by_pid - find a process with a matching PID value. |
| 4064 | * @pid: the pid in question. |
| 4065 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4066 | static inline struct task_struct *find_process_by_pid(pid_t pid) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4067 | { |
| 4068 | return pid ? find_task_by_pid(pid) : current; |
| 4069 | } |
| 4070 | |
| 4071 | /* Actually do priority change: must hold rq lock. */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4072 | static void |
| 4073 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4074 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4075 | BUG_ON(p->se.on_rq); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 4076 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4077 | p->policy = policy; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4078 | switch (p->policy) { |
| 4079 | case SCHED_NORMAL: |
| 4080 | case SCHED_BATCH: |
| 4081 | case SCHED_IDLE: |
| 4082 | p->sched_class = &fair_sched_class; |
| 4083 | break; |
| 4084 | case SCHED_FIFO: |
| 4085 | case SCHED_RR: |
| 4086 | p->sched_class = &rt_sched_class; |
| 4087 | break; |
| 4088 | } |
| 4089 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4090 | p->rt_priority = prio; |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4091 | p->normal_prio = normal_prio(p); |
| 4092 | /* we are holding p->pi_lock already */ |
| 4093 | p->prio = rt_mutex_getprio(p); |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 4094 | set_load_weight(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4095 | } |
| 4096 | |
| 4097 | /** |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 4098 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4099 | * @p: the task in question. |
| 4100 | * @policy: new policy. |
| 4101 | * @param: structure containing the new RT priority. |
Oleg Nesterov | 5fe1d75 | 2006-09-29 02:00:48 -0700 | [diff] [blame] | 4102 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 4103 | * NOTE that the task may be already dead. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4104 | */ |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 4105 | int sched_setscheduler(struct task_struct *p, int policy, |
| 4106 | struct sched_param *param) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4107 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4108 | int retval, oldprio, oldpolicy = -1, on_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4109 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4110 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4111 | |
Steven Rostedt | 66e5393 | 2006-06-27 02:54:44 -0700 | [diff] [blame] | 4112 | /* may grab non-irq protected spin_locks */ |
| 4113 | BUG_ON(in_interrupt()); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4114 | recheck: |
| 4115 | /* double check policy once rq lock held */ |
| 4116 | if (policy < 0) |
| 4117 | policy = oldpolicy = p->policy; |
| 4118 | else if (policy != SCHED_FIFO && policy != SCHED_RR && |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4119 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
| 4120 | policy != SCHED_IDLE) |
Ingo Molnar | b0a9499 | 2006-01-14 13:20:41 -0800 | [diff] [blame] | 4121 | return -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4122 | /* |
| 4123 | * Valid priorities for SCHED_FIFO and SCHED_RR are |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4124 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
| 4125 | * SCHED_BATCH and SCHED_IDLE is 0. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4126 | */ |
| 4127 | if (param->sched_priority < 0 || |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 4128 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
Steven Rostedt | d46523e | 2005-07-25 16:28:39 -0400 | [diff] [blame] | 4129 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4130 | return -EINVAL; |
Ingo Molnar | e05606d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4131 | if (rt_policy(policy) != (param->sched_priority != 0)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4132 | return -EINVAL; |
| 4133 | |
Olivier Croquette | 37e4ab3 | 2005-06-25 14:57:32 -0700 | [diff] [blame] | 4134 | /* |
| 4135 | * Allow unprivileged RT tasks to decrease priority: |
| 4136 | */ |
| 4137 | if (!capable(CAP_SYS_NICE)) { |
Ingo Molnar | e05606d | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4138 | if (rt_policy(policy)) { |
Oleg Nesterov | 8dc3e90 | 2006-09-29 02:00:50 -0700 | [diff] [blame] | 4139 | unsigned long rlim_rtprio; |
Oleg Nesterov | 5fe1d75 | 2006-09-29 02:00:48 -0700 | [diff] [blame] | 4140 | |
Oleg Nesterov | 8dc3e90 | 2006-09-29 02:00:50 -0700 | [diff] [blame] | 4141 | if (!lock_task_sighand(p, &flags)) |
| 4142 | return -ESRCH; |
| 4143 | rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; |
| 4144 | unlock_task_sighand(p, &flags); |
Oleg Nesterov | 5fe1d75 | 2006-09-29 02:00:48 -0700 | [diff] [blame] | 4145 | |
Oleg Nesterov | 8dc3e90 | 2006-09-29 02:00:50 -0700 | [diff] [blame] | 4146 | /* can't set/change the rt policy */ |
| 4147 | if (policy != p->policy && !rlim_rtprio) |
| 4148 | return -EPERM; |
| 4149 | |
| 4150 | /* can't increase priority */ |
| 4151 | if (param->sched_priority > p->rt_priority && |
| 4152 | param->sched_priority > rlim_rtprio) |
| 4153 | return -EPERM; |
| 4154 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4155 | /* |
| 4156 | * Like positive nice levels, dont allow tasks to |
| 4157 | * move out of SCHED_IDLE either: |
| 4158 | */ |
| 4159 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) |
| 4160 | return -EPERM; |
Oleg Nesterov | 8dc3e90 | 2006-09-29 02:00:50 -0700 | [diff] [blame] | 4161 | |
Olivier Croquette | 37e4ab3 | 2005-06-25 14:57:32 -0700 | [diff] [blame] | 4162 | /* can't change other user's priorities */ |
| 4163 | if ((current->euid != p->euid) && |
| 4164 | (current->euid != p->uid)) |
| 4165 | return -EPERM; |
| 4166 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4167 | |
| 4168 | retval = security_task_setscheduler(p, policy, param); |
| 4169 | if (retval) |
| 4170 | return retval; |
| 4171 | /* |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4172 | * make sure no PI-waiters arrive (or leave) while we are |
| 4173 | * changing the priority of the task: |
| 4174 | */ |
| 4175 | spin_lock_irqsave(&p->pi_lock, flags); |
| 4176 | /* |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4177 | * To be able to change p->policy safely, the apropriate |
| 4178 | * runqueue lock must be held. |
| 4179 | */ |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4180 | rq = __task_rq_lock(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4181 | /* recheck policy now with rq lock held */ |
| 4182 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
| 4183 | policy = oldpolicy = -1; |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4184 | __task_rq_unlock(rq); |
| 4185 | spin_unlock_irqrestore(&p->pi_lock, flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4186 | goto recheck; |
| 4187 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4188 | on_rq = p->se.on_rq; |
| 4189 | if (on_rq) |
| 4190 | deactivate_task(rq, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4191 | oldprio = p->prio; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4192 | __setscheduler(rq, p, policy, param->sched_priority); |
| 4193 | if (on_rq) { |
| 4194 | activate_task(rq, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4195 | /* |
| 4196 | * Reschedule if we are currently running on this runqueue and |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 4197 | * our priority decreased, or if we are not currently running on |
| 4198 | * this runqueue and our priority is higher than the current's |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4199 | */ |
Andrew Morton | d5f9f94 | 2007-05-08 20:27:06 -0700 | [diff] [blame] | 4200 | if (task_running(rq, p)) { |
| 4201 | if (p->prio > oldprio) |
| 4202 | resched_task(rq->curr); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4203 | } else { |
| 4204 | check_preempt_curr(rq, p); |
| 4205 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4206 | } |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4207 | __task_rq_unlock(rq); |
| 4208 | spin_unlock_irqrestore(&p->pi_lock, flags); |
| 4209 | |
Thomas Gleixner | 95e02ca | 2006-06-27 02:55:02 -0700 | [diff] [blame] | 4210 | rt_mutex_adjust_pi(p); |
| 4211 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4212 | return 0; |
| 4213 | } |
| 4214 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
| 4215 | |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 4216 | static int |
| 4217 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4218 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4219 | struct sched_param lparam; |
| 4220 | struct task_struct *p; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4221 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4222 | |
| 4223 | if (!param || pid < 0) |
| 4224 | return -EINVAL; |
| 4225 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
| 4226 | return -EFAULT; |
Oleg Nesterov | 5fe1d75 | 2006-09-29 02:00:48 -0700 | [diff] [blame] | 4227 | |
| 4228 | rcu_read_lock(); |
| 4229 | retval = -ESRCH; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4230 | p = find_process_by_pid(pid); |
Oleg Nesterov | 5fe1d75 | 2006-09-29 02:00:48 -0700 | [diff] [blame] | 4231 | if (p != NULL) |
| 4232 | retval = sched_setscheduler(p, policy, &lparam); |
| 4233 | rcu_read_unlock(); |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4234 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4235 | return retval; |
| 4236 | } |
| 4237 | |
| 4238 | /** |
| 4239 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
| 4240 | * @pid: the pid in question. |
| 4241 | * @policy: new policy. |
| 4242 | * @param: structure containing the new RT priority. |
| 4243 | */ |
| 4244 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, |
| 4245 | struct sched_param __user *param) |
| 4246 | { |
Jason Baron | c21761f | 2006-01-18 17:43:03 -0800 | [diff] [blame] | 4247 | /* negative values for policy are not valid */ |
| 4248 | if (policy < 0) |
| 4249 | return -EINVAL; |
| 4250 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4251 | return do_sched_setscheduler(pid, policy, param); |
| 4252 | } |
| 4253 | |
| 4254 | /** |
| 4255 | * sys_sched_setparam - set/change the RT priority of a thread |
| 4256 | * @pid: the pid in question. |
| 4257 | * @param: structure containing the new RT priority. |
| 4258 | */ |
| 4259 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) |
| 4260 | { |
| 4261 | return do_sched_setscheduler(pid, -1, param); |
| 4262 | } |
| 4263 | |
| 4264 | /** |
| 4265 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
| 4266 | * @pid: the pid in question. |
| 4267 | */ |
| 4268 | asmlinkage long sys_sched_getscheduler(pid_t pid) |
| 4269 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4270 | struct task_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4271 | int retval = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4272 | |
| 4273 | if (pid < 0) |
| 4274 | goto out_nounlock; |
| 4275 | |
| 4276 | retval = -ESRCH; |
| 4277 | read_lock(&tasklist_lock); |
| 4278 | p = find_process_by_pid(pid); |
| 4279 | if (p) { |
| 4280 | retval = security_task_getscheduler(p); |
| 4281 | if (!retval) |
| 4282 | retval = p->policy; |
| 4283 | } |
| 4284 | read_unlock(&tasklist_lock); |
| 4285 | |
| 4286 | out_nounlock: |
| 4287 | return retval; |
| 4288 | } |
| 4289 | |
| 4290 | /** |
| 4291 | * sys_sched_getscheduler - get the RT priority of a thread |
| 4292 | * @pid: the pid in question. |
| 4293 | * @param: structure containing the RT priority. |
| 4294 | */ |
| 4295 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) |
| 4296 | { |
| 4297 | struct sched_param lp; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4298 | struct task_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4299 | int retval = -EINVAL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4300 | |
| 4301 | if (!param || pid < 0) |
| 4302 | goto out_nounlock; |
| 4303 | |
| 4304 | read_lock(&tasklist_lock); |
| 4305 | p = find_process_by_pid(pid); |
| 4306 | retval = -ESRCH; |
| 4307 | if (!p) |
| 4308 | goto out_unlock; |
| 4309 | |
| 4310 | retval = security_task_getscheduler(p); |
| 4311 | if (retval) |
| 4312 | goto out_unlock; |
| 4313 | |
| 4314 | lp.sched_priority = p->rt_priority; |
| 4315 | read_unlock(&tasklist_lock); |
| 4316 | |
| 4317 | /* |
| 4318 | * This one might sleep, we cannot do it with a spinlock held ... |
| 4319 | */ |
| 4320 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
| 4321 | |
| 4322 | out_nounlock: |
| 4323 | return retval; |
| 4324 | |
| 4325 | out_unlock: |
| 4326 | read_unlock(&tasklist_lock); |
| 4327 | return retval; |
| 4328 | } |
| 4329 | |
| 4330 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) |
| 4331 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4332 | cpumask_t cpus_allowed; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4333 | struct task_struct *p; |
| 4334 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4335 | |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 4336 | mutex_lock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4337 | read_lock(&tasklist_lock); |
| 4338 | |
| 4339 | p = find_process_by_pid(pid); |
| 4340 | if (!p) { |
| 4341 | read_unlock(&tasklist_lock); |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 4342 | mutex_unlock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4343 | return -ESRCH; |
| 4344 | } |
| 4345 | |
| 4346 | /* |
| 4347 | * It is not safe to call set_cpus_allowed with the |
| 4348 | * tasklist_lock held. We will bump the task_struct's |
| 4349 | * usage count and then drop tasklist_lock. |
| 4350 | */ |
| 4351 | get_task_struct(p); |
| 4352 | read_unlock(&tasklist_lock); |
| 4353 | |
| 4354 | retval = -EPERM; |
| 4355 | if ((current->euid != p->euid) && (current->euid != p->uid) && |
| 4356 | !capable(CAP_SYS_NICE)) |
| 4357 | goto out_unlock; |
| 4358 | |
David Quigley | e7834f8 | 2006-06-23 02:03:59 -0700 | [diff] [blame] | 4359 | retval = security_task_setscheduler(p, 0, NULL); |
| 4360 | if (retval) |
| 4361 | goto out_unlock; |
| 4362 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4363 | cpus_allowed = cpuset_cpus_allowed(p); |
| 4364 | cpus_and(new_mask, new_mask, cpus_allowed); |
| 4365 | retval = set_cpus_allowed(p, new_mask); |
| 4366 | |
| 4367 | out_unlock: |
| 4368 | put_task_struct(p); |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 4369 | mutex_unlock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4370 | return retval; |
| 4371 | } |
| 4372 | |
| 4373 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
| 4374 | cpumask_t *new_mask) |
| 4375 | { |
| 4376 | if (len < sizeof(cpumask_t)) { |
| 4377 | memset(new_mask, 0, sizeof(cpumask_t)); |
| 4378 | } else if (len > sizeof(cpumask_t)) { |
| 4379 | len = sizeof(cpumask_t); |
| 4380 | } |
| 4381 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
| 4382 | } |
| 4383 | |
| 4384 | /** |
| 4385 | * sys_sched_setaffinity - set the cpu affinity of a process |
| 4386 | * @pid: pid of the process |
| 4387 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
| 4388 | * @user_mask_ptr: user-space pointer to the new cpu mask |
| 4389 | */ |
| 4390 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, |
| 4391 | unsigned long __user *user_mask_ptr) |
| 4392 | { |
| 4393 | cpumask_t new_mask; |
| 4394 | int retval; |
| 4395 | |
| 4396 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); |
| 4397 | if (retval) |
| 4398 | return retval; |
| 4399 | |
| 4400 | return sched_setaffinity(pid, new_mask); |
| 4401 | } |
| 4402 | |
| 4403 | /* |
| 4404 | * Represents all cpu's present in the system |
| 4405 | * In systems capable of hotplug, this map could dynamically grow |
| 4406 | * as new cpu's are detected in the system via any platform specific |
| 4407 | * method, such as ACPI for e.g. |
| 4408 | */ |
| 4409 | |
Andi Kleen | 4cef0c6 | 2006-01-11 22:44:57 +0100 | [diff] [blame] | 4410 | cpumask_t cpu_present_map __read_mostly; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4411 | EXPORT_SYMBOL(cpu_present_map); |
| 4412 | |
| 4413 | #ifndef CONFIG_SMP |
Andi Kleen | 4cef0c6 | 2006-01-11 22:44:57 +0100 | [diff] [blame] | 4414 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
Greg Banks | e16b38f | 2006-10-02 02:17:40 -0700 | [diff] [blame] | 4415 | EXPORT_SYMBOL(cpu_online_map); |
| 4416 | |
Andi Kleen | 4cef0c6 | 2006-01-11 22:44:57 +0100 | [diff] [blame] | 4417 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
Greg Banks | e16b38f | 2006-10-02 02:17:40 -0700 | [diff] [blame] | 4418 | EXPORT_SYMBOL(cpu_possible_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4419 | #endif |
| 4420 | |
| 4421 | long sched_getaffinity(pid_t pid, cpumask_t *mask) |
| 4422 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4423 | struct task_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4424 | int retval; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4425 | |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 4426 | mutex_lock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4427 | read_lock(&tasklist_lock); |
| 4428 | |
| 4429 | retval = -ESRCH; |
| 4430 | p = find_process_by_pid(pid); |
| 4431 | if (!p) |
| 4432 | goto out_unlock; |
| 4433 | |
David Quigley | e7834f8 | 2006-06-23 02:03:59 -0700 | [diff] [blame] | 4434 | retval = security_task_getscheduler(p); |
| 4435 | if (retval) |
| 4436 | goto out_unlock; |
| 4437 | |
Jack Steiner | 2f7016d | 2006-02-01 03:05:18 -0800 | [diff] [blame] | 4438 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4439 | |
| 4440 | out_unlock: |
| 4441 | read_unlock(&tasklist_lock); |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 4442 | mutex_unlock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4443 | if (retval) |
| 4444 | return retval; |
| 4445 | |
| 4446 | return 0; |
| 4447 | } |
| 4448 | |
| 4449 | /** |
| 4450 | * sys_sched_getaffinity - get the cpu affinity of a process |
| 4451 | * @pid: pid of the process |
| 4452 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
| 4453 | * @user_mask_ptr: user-space pointer to hold the current cpu mask |
| 4454 | */ |
| 4455 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, |
| 4456 | unsigned long __user *user_mask_ptr) |
| 4457 | { |
| 4458 | int ret; |
| 4459 | cpumask_t mask; |
| 4460 | |
| 4461 | if (len < sizeof(cpumask_t)) |
| 4462 | return -EINVAL; |
| 4463 | |
| 4464 | ret = sched_getaffinity(pid, &mask); |
| 4465 | if (ret < 0) |
| 4466 | return ret; |
| 4467 | |
| 4468 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) |
| 4469 | return -EFAULT; |
| 4470 | |
| 4471 | return sizeof(cpumask_t); |
| 4472 | } |
| 4473 | |
| 4474 | /** |
| 4475 | * sys_sched_yield - yield the current processor to other threads. |
| 4476 | * |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4477 | * This function yields the current CPU to other tasks. If there are no |
| 4478 | * other threads running on this CPU then this function will return. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4479 | */ |
| 4480 | asmlinkage long sys_sched_yield(void) |
| 4481 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4482 | struct rq *rq = this_rq_lock(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4483 | |
| 4484 | schedstat_inc(rq, yld_cnt); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4485 | if (unlikely(rq->nr_running == 1)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4486 | schedstat_inc(rq, yld_act_empty); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4487 | else |
| 4488 | current->sched_class->yield_task(rq, current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4489 | |
| 4490 | /* |
| 4491 | * Since we are going to call schedule() anyway, there's |
| 4492 | * no need to preempt or enable interrupts: |
| 4493 | */ |
| 4494 | __release(rq->lock); |
Ingo Molnar | 8a25d5d | 2006-07-03 00:24:54 -0700 | [diff] [blame] | 4495 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4496 | _raw_spin_unlock(&rq->lock); |
| 4497 | preempt_enable_no_resched(); |
| 4498 | |
| 4499 | schedule(); |
| 4500 | |
| 4501 | return 0; |
| 4502 | } |
| 4503 | |
Andrew Morton | e7b3840 | 2006-06-30 01:56:00 -0700 | [diff] [blame] | 4504 | static void __cond_resched(void) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4505 | { |
Ingo Molnar | 8e0a43d | 2006-06-23 02:05:23 -0700 | [diff] [blame] | 4506 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
| 4507 | __might_sleep(__FILE__, __LINE__); |
| 4508 | #endif |
Ingo Molnar | 5bbcfd9 | 2005-07-07 17:57:04 -0700 | [diff] [blame] | 4509 | /* |
| 4510 | * The BKS might be reacquired before we have dropped |
| 4511 | * PREEMPT_ACTIVE, which could trigger a second |
| 4512 | * cond_resched() call. |
| 4513 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4514 | do { |
| 4515 | add_preempt_count(PREEMPT_ACTIVE); |
| 4516 | schedule(); |
| 4517 | sub_preempt_count(PREEMPT_ACTIVE); |
| 4518 | } while (need_resched()); |
| 4519 | } |
| 4520 | |
| 4521 | int __sched cond_resched(void) |
| 4522 | { |
Ingo Molnar | 9414232 | 2006-12-29 16:48:13 -0800 | [diff] [blame] | 4523 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
| 4524 | system_state == SYSTEM_RUNNING) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4525 | __cond_resched(); |
| 4526 | return 1; |
| 4527 | } |
| 4528 | return 0; |
| 4529 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4530 | EXPORT_SYMBOL(cond_resched); |
| 4531 | |
| 4532 | /* |
| 4533 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, |
| 4534 | * call schedule, and on return reacquire the lock. |
| 4535 | * |
| 4536 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
| 4537 | * operations here to prevent schedule() from being called twice (once via |
| 4538 | * spin_unlock(), once by hand). |
| 4539 | */ |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 4540 | int cond_resched_lock(spinlock_t *lock) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4541 | { |
Jan Kara | 6df3cec | 2005-06-13 15:52:32 -0700 | [diff] [blame] | 4542 | int ret = 0; |
| 4543 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4544 | if (need_lockbreak(lock)) { |
| 4545 | spin_unlock(lock); |
| 4546 | cpu_relax(); |
Jan Kara | 6df3cec | 2005-06-13 15:52:32 -0700 | [diff] [blame] | 4547 | ret = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4548 | spin_lock(lock); |
| 4549 | } |
Ingo Molnar | 9414232 | 2006-12-29 16:48:13 -0800 | [diff] [blame] | 4550 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
Ingo Molnar | 8a25d5d | 2006-07-03 00:24:54 -0700 | [diff] [blame] | 4551 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4552 | _raw_spin_unlock(lock); |
| 4553 | preempt_enable_no_resched(); |
| 4554 | __cond_resched(); |
Jan Kara | 6df3cec | 2005-06-13 15:52:32 -0700 | [diff] [blame] | 4555 | ret = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4556 | spin_lock(lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4557 | } |
Jan Kara | 6df3cec | 2005-06-13 15:52:32 -0700 | [diff] [blame] | 4558 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4559 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4560 | EXPORT_SYMBOL(cond_resched_lock); |
| 4561 | |
| 4562 | int __sched cond_resched_softirq(void) |
| 4563 | { |
| 4564 | BUG_ON(!in_softirq()); |
| 4565 | |
Ingo Molnar | 9414232 | 2006-12-29 16:48:13 -0800 | [diff] [blame] | 4566 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
Thomas Gleixner | 98d8256 | 2007-05-23 13:58:18 -0700 | [diff] [blame] | 4567 | local_bh_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4568 | __cond_resched(); |
| 4569 | local_bh_disable(); |
| 4570 | return 1; |
| 4571 | } |
| 4572 | return 0; |
| 4573 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4574 | EXPORT_SYMBOL(cond_resched_softirq); |
| 4575 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4576 | /** |
| 4577 | * yield - yield the current processor to other threads. |
| 4578 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame] | 4579 | * This is a shortcut for kernel-space yielding - it marks the |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4580 | * thread runnable and calls sys_sched_yield(). |
| 4581 | */ |
| 4582 | void __sched yield(void) |
| 4583 | { |
| 4584 | set_current_state(TASK_RUNNING); |
| 4585 | sys_sched_yield(); |
| 4586 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4587 | EXPORT_SYMBOL(yield); |
| 4588 | |
| 4589 | /* |
| 4590 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
| 4591 | * that process accounting knows that this is a task in IO wait state. |
| 4592 | * |
| 4593 | * But don't do that if it is a deliberate, throttling IO wait (this task |
| 4594 | * has set its backing_dev_info: the queue against which it should throttle) |
| 4595 | */ |
| 4596 | void __sched io_schedule(void) |
| 4597 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4598 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4599 | |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 4600 | delayacct_blkio_start(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4601 | atomic_inc(&rq->nr_iowait); |
| 4602 | schedule(); |
| 4603 | atomic_dec(&rq->nr_iowait); |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 4604 | delayacct_blkio_end(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4605 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4606 | EXPORT_SYMBOL(io_schedule); |
| 4607 | |
| 4608 | long __sched io_schedule_timeout(long timeout) |
| 4609 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4610 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4611 | long ret; |
| 4612 | |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 4613 | delayacct_blkio_start(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4614 | atomic_inc(&rq->nr_iowait); |
| 4615 | ret = schedule_timeout(timeout); |
| 4616 | atomic_dec(&rq->nr_iowait); |
Shailabh Nagar | 0ff9224 | 2006-07-14 00:24:37 -0700 | [diff] [blame] | 4617 | delayacct_blkio_end(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4618 | return ret; |
| 4619 | } |
| 4620 | |
| 4621 | /** |
| 4622 | * sys_sched_get_priority_max - return maximum RT priority. |
| 4623 | * @policy: scheduling class. |
| 4624 | * |
| 4625 | * this syscall returns the maximum rt_priority that can be used |
| 4626 | * by a given scheduling class. |
| 4627 | */ |
| 4628 | asmlinkage long sys_sched_get_priority_max(int policy) |
| 4629 | { |
| 4630 | int ret = -EINVAL; |
| 4631 | |
| 4632 | switch (policy) { |
| 4633 | case SCHED_FIFO: |
| 4634 | case SCHED_RR: |
| 4635 | ret = MAX_USER_RT_PRIO-1; |
| 4636 | break; |
| 4637 | case SCHED_NORMAL: |
Ingo Molnar | b0a9499 | 2006-01-14 13:20:41 -0800 | [diff] [blame] | 4638 | case SCHED_BATCH: |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4639 | case SCHED_IDLE: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4640 | ret = 0; |
| 4641 | break; |
| 4642 | } |
| 4643 | return ret; |
| 4644 | } |
| 4645 | |
| 4646 | /** |
| 4647 | * sys_sched_get_priority_min - return minimum RT priority. |
| 4648 | * @policy: scheduling class. |
| 4649 | * |
| 4650 | * this syscall returns the minimum rt_priority that can be used |
| 4651 | * by a given scheduling class. |
| 4652 | */ |
| 4653 | asmlinkage long sys_sched_get_priority_min(int policy) |
| 4654 | { |
| 4655 | int ret = -EINVAL; |
| 4656 | |
| 4657 | switch (policy) { |
| 4658 | case SCHED_FIFO: |
| 4659 | case SCHED_RR: |
| 4660 | ret = 1; |
| 4661 | break; |
| 4662 | case SCHED_NORMAL: |
Ingo Molnar | b0a9499 | 2006-01-14 13:20:41 -0800 | [diff] [blame] | 4663 | case SCHED_BATCH: |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4664 | case SCHED_IDLE: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4665 | ret = 0; |
| 4666 | } |
| 4667 | return ret; |
| 4668 | } |
| 4669 | |
| 4670 | /** |
| 4671 | * sys_sched_rr_get_interval - return the default timeslice of a process. |
| 4672 | * @pid: pid of the process. |
| 4673 | * @interval: userspace pointer to the timeslice value. |
| 4674 | * |
| 4675 | * this syscall writes the default timeslice value of a given process |
| 4676 | * into the user-space timespec buffer. A value of '0' means infinity. |
| 4677 | */ |
| 4678 | asmlinkage |
| 4679 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) |
| 4680 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4681 | struct task_struct *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4682 | int retval = -EINVAL; |
| 4683 | struct timespec t; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4684 | |
| 4685 | if (pid < 0) |
| 4686 | goto out_nounlock; |
| 4687 | |
| 4688 | retval = -ESRCH; |
| 4689 | read_lock(&tasklist_lock); |
| 4690 | p = find_process_by_pid(pid); |
| 4691 | if (!p) |
| 4692 | goto out_unlock; |
| 4693 | |
| 4694 | retval = security_task_getscheduler(p); |
| 4695 | if (retval) |
| 4696 | goto out_unlock; |
| 4697 | |
Peter Williams | b78709c | 2006-06-26 16:58:00 +1000 | [diff] [blame] | 4698 | jiffies_to_timespec(p->policy == SCHED_FIFO ? |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4699 | 0 : static_prio_timeslice(p->static_prio), &t); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4700 | read_unlock(&tasklist_lock); |
| 4701 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
| 4702 | out_nounlock: |
| 4703 | return retval; |
| 4704 | out_unlock: |
| 4705 | read_unlock(&tasklist_lock); |
| 4706 | return retval; |
| 4707 | } |
| 4708 | |
Andreas Mohr | 2ed6e34 | 2006-07-10 04:43:52 -0700 | [diff] [blame] | 4709 | static const char stat_nam[] = "RSDTtZX"; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4710 | |
| 4711 | static void show_task(struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4712 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4713 | unsigned long free = 0; |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4714 | unsigned state; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4715 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4716 | state = p->state ? __ffs(p->state) + 1 : 0; |
Andreas Mohr | 2ed6e34 | 2006-07-10 04:43:52 -0700 | [diff] [blame] | 4717 | printk("%-13.13s %c", p->comm, |
| 4718 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4719 | #if (BITS_PER_LONG == 32) |
| 4720 | if (state == TASK_RUNNING) |
| 4721 | printk(" running "); |
| 4722 | else |
| 4723 | printk(" %08lX ", thread_saved_pc(p)); |
| 4724 | #else |
| 4725 | if (state == TASK_RUNNING) |
| 4726 | printk(" running task "); |
| 4727 | else |
| 4728 | printk(" %016lx ", thread_saved_pc(p)); |
| 4729 | #endif |
| 4730 | #ifdef CONFIG_DEBUG_STACK_USAGE |
| 4731 | { |
Al Viro | 10ebffd | 2005-11-13 16:06:56 -0800 | [diff] [blame] | 4732 | unsigned long *n = end_of_stack(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4733 | while (!*n) |
| 4734 | n++; |
Al Viro | 10ebffd | 2005-11-13 16:06:56 -0800 | [diff] [blame] | 4735 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4736 | } |
| 4737 | #endif |
Ingo Molnar | 35f6f75 | 2007-04-06 21:18:06 +0200 | [diff] [blame] | 4738 | printk("%5lu %5d %6d", free, p->pid, p->parent->pid); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4739 | if (!p->mm) |
| 4740 | printk(" (L-TLB)\n"); |
| 4741 | else |
| 4742 | printk(" (NOTLB)\n"); |
| 4743 | |
| 4744 | if (state != TASK_RUNNING) |
| 4745 | show_stack(p, NULL); |
| 4746 | } |
| 4747 | |
Ingo Molnar | e59e2ae | 2006-12-06 20:35:59 -0800 | [diff] [blame] | 4748 | void show_state_filter(unsigned long state_filter) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4749 | { |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4750 | struct task_struct *g, *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4751 | |
| 4752 | #if (BITS_PER_LONG == 32) |
| 4753 | printk("\n" |
Chris Caputo | 301827a | 2006-12-06 20:39:11 -0800 | [diff] [blame] | 4754 | " free sibling\n"); |
| 4755 | printk(" task PC stack pid father child younger older\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4756 | #else |
| 4757 | printk("\n" |
Chris Caputo | 301827a | 2006-12-06 20:39:11 -0800 | [diff] [blame] | 4758 | " free sibling\n"); |
| 4759 | printk(" task PC stack pid father child younger older\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4760 | #endif |
| 4761 | read_lock(&tasklist_lock); |
| 4762 | do_each_thread(g, p) { |
| 4763 | /* |
| 4764 | * reset the NMI-timeout, listing all files on a slow |
| 4765 | * console might take alot of time: |
| 4766 | */ |
| 4767 | touch_nmi_watchdog(); |
Ingo Molnar | 39bc89f | 2007-04-25 20:50:03 -0700 | [diff] [blame] | 4768 | if (!state_filter || (p->state & state_filter)) |
Ingo Molnar | e59e2ae | 2006-12-06 20:35:59 -0800 | [diff] [blame] | 4769 | show_task(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4770 | } while_each_thread(g, p); |
| 4771 | |
Jeremy Fitzhardinge | 04c9167 | 2007-05-08 00:28:05 -0700 | [diff] [blame] | 4772 | touch_all_softlockup_watchdogs(); |
| 4773 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4774 | #ifdef CONFIG_SCHED_DEBUG |
| 4775 | sysrq_sched_debug_show(); |
| 4776 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4777 | read_unlock(&tasklist_lock); |
Ingo Molnar | e59e2ae | 2006-12-06 20:35:59 -0800 | [diff] [blame] | 4778 | /* |
| 4779 | * Only show locks if all tasks are dumped: |
| 4780 | */ |
| 4781 | if (state_filter == -1) |
| 4782 | debug_show_all_locks(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4783 | } |
| 4784 | |
Ingo Molnar | 1df2105 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4785 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
| 4786 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4787 | idle->sched_class = &idle_sched_class; |
Ingo Molnar | 1df2105 | 2007-07-09 18:51:58 +0200 | [diff] [blame] | 4788 | } |
| 4789 | |
Ingo Molnar | f340c0d | 2005-06-28 16:40:42 +0200 | [diff] [blame] | 4790 | /** |
| 4791 | * init_idle - set up an idle thread for a given CPU |
| 4792 | * @idle: task in question |
| 4793 | * @cpu: cpu the idle task belongs to |
| 4794 | * |
| 4795 | * NOTE: this function does not set the idle thread's NEED_RESCHED |
| 4796 | * flag, to make booting more robust. |
| 4797 | */ |
Nick Piggin | 5c1e176 | 2006-10-03 01:14:04 -0700 | [diff] [blame] | 4798 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4799 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4800 | struct rq *rq = cpu_rq(cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4801 | unsigned long flags; |
| 4802 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4803 | __sched_fork(idle); |
| 4804 | idle->se.exec_start = sched_clock(); |
| 4805 | |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 4806 | idle->prio = idle->normal_prio = MAX_PRIO; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4807 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4808 | __set_task_cpu(idle, cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4809 | |
| 4810 | spin_lock_irqsave(&rq->lock, flags); |
| 4811 | rq->curr = rq->idle = idle; |
Nick Piggin | 4866cde | 2005-06-25 14:57:23 -0700 | [diff] [blame] | 4812 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
| 4813 | idle->oncpu = 1; |
| 4814 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4815 | spin_unlock_irqrestore(&rq->lock, flags); |
| 4816 | |
| 4817 | /* Set the preempt count _outside_ the spinlocks! */ |
| 4818 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 4819 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4820 | #else |
Al Viro | a1261f5 | 2005-11-13 16:06:55 -0800 | [diff] [blame] | 4821 | task_thread_info(idle)->preempt_count = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4822 | #endif |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4823 | /* |
| 4824 | * The idle tasks have their own, simple scheduling class: |
| 4825 | */ |
| 4826 | idle->sched_class = &idle_sched_class; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4827 | } |
| 4828 | |
| 4829 | /* |
| 4830 | * In a system that switches off the HZ timer nohz_cpu_mask |
| 4831 | * indicates which cpus entered this state. This is used |
| 4832 | * in the rcu update to wait only for active cpus. For system |
| 4833 | * which do not switch off the HZ timer nohz_cpu_mask should |
| 4834 | * always be CPU_MASK_NONE. |
| 4835 | */ |
| 4836 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; |
| 4837 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4838 | /* |
| 4839 | * Increase the granularity value when there are more CPUs, |
| 4840 | * because with more CPUs the 'effective latency' as visible |
| 4841 | * to users decreases. But the relationship is not linear, |
| 4842 | * so pick a second-best guess by going with the log2 of the |
| 4843 | * number of CPUs. |
| 4844 | * |
| 4845 | * This idea comes from the SD scheduler of Con Kolivas: |
| 4846 | */ |
| 4847 | static inline void sched_init_granularity(void) |
| 4848 | { |
| 4849 | unsigned int factor = 1 + ilog2(num_online_cpus()); |
| 4850 | const unsigned long gran_limit = 10000000; |
| 4851 | |
| 4852 | sysctl_sched_granularity *= factor; |
| 4853 | if (sysctl_sched_granularity > gran_limit) |
| 4854 | sysctl_sched_granularity = gran_limit; |
| 4855 | |
| 4856 | sysctl_sched_runtime_limit = sysctl_sched_granularity * 4; |
| 4857 | sysctl_sched_wakeup_granularity = sysctl_sched_granularity / 2; |
| 4858 | } |
| 4859 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4860 | #ifdef CONFIG_SMP |
| 4861 | /* |
| 4862 | * This is how migration works: |
| 4863 | * |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4864 | * 1) we queue a struct migration_req structure in the source CPU's |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4865 | * runqueue and wake up that CPU's migration thread. |
| 4866 | * 2) we down() the locked semaphore => thread blocks. |
| 4867 | * 3) migration thread wakes up (implicitly it forces the migrated |
| 4868 | * thread off the CPU) |
| 4869 | * 4) it gets the migration request and checks whether the migrated |
| 4870 | * task is still in the wrong runqueue. |
| 4871 | * 5) if it's in the wrong runqueue then the migration thread removes |
| 4872 | * it and puts it into the right queue. |
| 4873 | * 6) migration thread up()s the semaphore. |
| 4874 | * 7) we wake up and the migration is done. |
| 4875 | */ |
| 4876 | |
| 4877 | /* |
| 4878 | * Change a given task's CPU affinity. Migrate the thread to a |
| 4879 | * proper CPU and schedule it away if the CPU it's executing on |
| 4880 | * is removed from the allowed bitmask. |
| 4881 | * |
| 4882 | * NOTE: the caller must have a valid reference to the task, the |
| 4883 | * task must not exit() & deallocate itself prematurely. The |
| 4884 | * call is not atomic; no spinlocks may be held. |
| 4885 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 4886 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4887 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4888 | struct migration_req req; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4889 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4890 | struct rq *rq; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 4891 | int ret = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4892 | |
| 4893 | rq = task_rq_lock(p, &flags); |
| 4894 | if (!cpus_intersects(new_mask, cpu_online_map)) { |
| 4895 | ret = -EINVAL; |
| 4896 | goto out; |
| 4897 | } |
| 4898 | |
| 4899 | p->cpus_allowed = new_mask; |
| 4900 | /* Can the task run on the task's current CPU? If so, we're done */ |
| 4901 | if (cpu_isset(task_cpu(p), new_mask)) |
| 4902 | goto out; |
| 4903 | |
| 4904 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { |
| 4905 | /* Need help from migration thread: drop lock and wait. */ |
| 4906 | task_rq_unlock(rq, &flags); |
| 4907 | wake_up_process(rq->migration_thread); |
| 4908 | wait_for_completion(&req.done); |
| 4909 | tlb_migrate_finish(p->mm); |
| 4910 | return 0; |
| 4911 | } |
| 4912 | out: |
| 4913 | task_rq_unlock(rq, &flags); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 4914 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4915 | return ret; |
| 4916 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4917 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
| 4918 | |
| 4919 | /* |
| 4920 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
| 4921 | * this because either it can't run here any more (set_cpus_allowed() |
| 4922 | * away from this CPU, or CPU going down), or because we're |
| 4923 | * attempting to rebalance this task on exec (sched_exec). |
| 4924 | * |
| 4925 | * So we race with normal scheduler movements, but that's OK, as long |
| 4926 | * as the task is no longer on this CPU. |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 4927 | * |
| 4928 | * Returns non-zero if task was successfully migrated. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4929 | */ |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 4930 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4931 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4932 | struct rq *rq_dest, *rq_src; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4933 | int ret = 0, on_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4934 | |
| 4935 | if (unlikely(cpu_is_offline(dest_cpu))) |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 4936 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4937 | |
| 4938 | rq_src = cpu_rq(src_cpu); |
| 4939 | rq_dest = cpu_rq(dest_cpu); |
| 4940 | |
| 4941 | double_rq_lock(rq_src, rq_dest); |
| 4942 | /* Already moved. */ |
| 4943 | if (task_cpu(p) != src_cpu) |
| 4944 | goto out; |
| 4945 | /* Affinity changed (again). */ |
| 4946 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) |
| 4947 | goto out; |
| 4948 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4949 | on_rq = p->se.on_rq; |
| 4950 | if (on_rq) |
| 4951 | deactivate_task(rq_src, p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4952 | set_task_cpu(p, dest_cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 4953 | if (on_rq) { |
| 4954 | activate_task(rq_dest, p, 0); |
| 4955 | check_preempt_curr(rq_dest, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4956 | } |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 4957 | ret = 1; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4958 | out: |
| 4959 | double_rq_unlock(rq_src, rq_dest); |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 4960 | return ret; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4961 | } |
| 4962 | |
| 4963 | /* |
| 4964 | * migration_thread - this is a highprio system thread that performs |
| 4965 | * thread migration by bumping thread off CPU then 'pushing' onto |
| 4966 | * another runqueue. |
| 4967 | */ |
Ingo Molnar | 95cdf3b | 2005-09-10 00:26:11 -0700 | [diff] [blame] | 4968 | static int migration_thread(void *data) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4969 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4970 | int cpu = (long)data; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4971 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4972 | |
| 4973 | rq = cpu_rq(cpu); |
| 4974 | BUG_ON(rq->migration_thread != current); |
| 4975 | |
| 4976 | set_current_state(TASK_INTERRUPTIBLE); |
| 4977 | while (!kthread_should_stop()) { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 4978 | struct migration_req *req; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4979 | struct list_head *head; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4980 | |
Christoph Lameter | 3e1d1d2 | 2005-06-24 23:13:50 -0700 | [diff] [blame] | 4981 | try_to_freeze(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 4982 | |
| 4983 | spin_lock_irq(&rq->lock); |
| 4984 | |
| 4985 | if (cpu_is_offline(cpu)) { |
| 4986 | spin_unlock_irq(&rq->lock); |
| 4987 | goto wait_to_die; |
| 4988 | } |
| 4989 | |
| 4990 | if (rq->active_balance) { |
| 4991 | active_load_balance(rq, cpu); |
| 4992 | rq->active_balance = 0; |
| 4993 | } |
| 4994 | |
| 4995 | head = &rq->migration_queue; |
| 4996 | |
| 4997 | if (list_empty(head)) { |
| 4998 | spin_unlock_irq(&rq->lock); |
| 4999 | schedule(); |
| 5000 | set_current_state(TASK_INTERRUPTIBLE); |
| 5001 | continue; |
| 5002 | } |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5003 | req = list_entry(head->next, struct migration_req, list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5004 | list_del_init(head->next); |
| 5005 | |
Nick Piggin | 674311d | 2005-06-25 14:57:27 -0700 | [diff] [blame] | 5006 | spin_unlock(&rq->lock); |
| 5007 | __migrate_task(req->task, cpu, req->dest_cpu); |
| 5008 | local_irq_enable(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5009 | |
| 5010 | complete(&req->done); |
| 5011 | } |
| 5012 | __set_current_state(TASK_RUNNING); |
| 5013 | return 0; |
| 5014 | |
| 5015 | wait_to_die: |
| 5016 | /* Wait for kthread_stop */ |
| 5017 | set_current_state(TASK_INTERRUPTIBLE); |
| 5018 | while (!kthread_should_stop()) { |
| 5019 | schedule(); |
| 5020 | set_current_state(TASK_INTERRUPTIBLE); |
| 5021 | } |
| 5022 | __set_current_state(TASK_RUNNING); |
| 5023 | return 0; |
| 5024 | } |
| 5025 | |
| 5026 | #ifdef CONFIG_HOTPLUG_CPU |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 5027 | /* |
| 5028 | * Figure out where task on dead CPU should go, use force if neccessary. |
| 5029 | * NOTE: interrupts should be disabled by the caller |
| 5030 | */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5031 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5032 | { |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 5033 | unsigned long flags; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5034 | cpumask_t mask; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5035 | struct rq *rq; |
| 5036 | int dest_cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5037 | |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 5038 | restart: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5039 | /* On same node? */ |
| 5040 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5041 | cpus_and(mask, mask, p->cpus_allowed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5042 | dest_cpu = any_online_cpu(mask); |
| 5043 | |
| 5044 | /* On any allowed CPU? */ |
| 5045 | if (dest_cpu == NR_CPUS) |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5046 | dest_cpu = any_online_cpu(p->cpus_allowed); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5047 | |
| 5048 | /* No more Mr. Nice Guy. */ |
| 5049 | if (dest_cpu == NR_CPUS) { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5050 | rq = task_rq_lock(p, &flags); |
| 5051 | cpus_setall(p->cpus_allowed); |
| 5052 | dest_cpu = any_online_cpu(p->cpus_allowed); |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 5053 | task_rq_unlock(rq, &flags); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5054 | |
| 5055 | /* |
| 5056 | * Don't tell them about moving exiting tasks or |
| 5057 | * kernel threads (both mm NULL), since they never |
| 5058 | * leave kernel. |
| 5059 | */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5060 | if (p->mm && printk_ratelimit()) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5061 | printk(KERN_INFO "process %d (%s) no " |
| 5062 | "longer affine to cpu%d\n", |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5063 | p->pid, p->comm, dead_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5064 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5065 | if (!__migrate_task(p, dead_cpu, dest_cpu)) |
Kirill Korotaev | efc3081 | 2006-06-27 02:54:32 -0700 | [diff] [blame] | 5066 | goto restart; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5067 | } |
| 5068 | |
| 5069 | /* |
| 5070 | * While a dead CPU has no uninterruptible tasks queued at this point, |
| 5071 | * it might still have a nonzero ->nr_uninterruptible counter, because |
| 5072 | * for performance reasons the counter is not stricly tracking tasks to |
| 5073 | * their home CPUs. So we just add the counter to another CPU's counter, |
| 5074 | * to keep the global sum constant after CPU-down: |
| 5075 | */ |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5076 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5077 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5078 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5079 | unsigned long flags; |
| 5080 | |
| 5081 | local_irq_save(flags); |
| 5082 | double_rq_lock(rq_src, rq_dest); |
| 5083 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
| 5084 | rq_src->nr_uninterruptible = 0; |
| 5085 | double_rq_unlock(rq_src, rq_dest); |
| 5086 | local_irq_restore(flags); |
| 5087 | } |
| 5088 | |
| 5089 | /* Run through task list and migrate tasks from the dead cpu. */ |
| 5090 | static void migrate_live_tasks(int src_cpu) |
| 5091 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5092 | struct task_struct *p, *t; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5093 | |
| 5094 | write_lock_irq(&tasklist_lock); |
| 5095 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5096 | do_each_thread(t, p) { |
| 5097 | if (p == current) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5098 | continue; |
| 5099 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5100 | if (task_cpu(p) == src_cpu) |
| 5101 | move_task_off_dead_cpu(src_cpu, p); |
| 5102 | } while_each_thread(t, p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5103 | |
| 5104 | write_unlock_irq(&tasklist_lock); |
| 5105 | } |
| 5106 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5107 | /* |
| 5108 | * Schedules idle task to be the next runnable task on current CPU. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5109 | * It does so by boosting its priority to highest possible and adding it to |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5110 | * the _front_ of the runqueue. Used by CPU offline code. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5111 | */ |
| 5112 | void sched_idle_next(void) |
| 5113 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5114 | int this_cpu = smp_processor_id(); |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5115 | struct rq *rq = cpu_rq(this_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5116 | struct task_struct *p = rq->idle; |
| 5117 | unsigned long flags; |
| 5118 | |
| 5119 | /* cpu has to be offline */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5120 | BUG_ON(cpu_online(this_cpu)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5121 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5122 | /* |
| 5123 | * Strictly not necessary since rest of the CPUs are stopped by now |
| 5124 | * and interrupts disabled on the current cpu. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5125 | */ |
| 5126 | spin_lock_irqsave(&rq->lock, flags); |
| 5127 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5128 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5129 | |
| 5130 | /* Add idle task to the _front_ of its priority queue: */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5131 | activate_idle_task(p, rq); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5132 | |
| 5133 | spin_unlock_irqrestore(&rq->lock, flags); |
| 5134 | } |
| 5135 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5136 | /* |
| 5137 | * Ensures that the idle task is using init_mm right before its cpu goes |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5138 | * offline. |
| 5139 | */ |
| 5140 | void idle_task_exit(void) |
| 5141 | { |
| 5142 | struct mm_struct *mm = current->active_mm; |
| 5143 | |
| 5144 | BUG_ON(cpu_online(smp_processor_id())); |
| 5145 | |
| 5146 | if (mm != &init_mm) |
| 5147 | switch_mm(mm, &init_mm, current); |
| 5148 | mmdrop(mm); |
| 5149 | } |
| 5150 | |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 5151 | /* called under rq->lock with disabled interrupts */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 5152 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5153 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5154 | struct rq *rq = cpu_rq(dead_cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5155 | |
| 5156 | /* Must be exiting, otherwise would be on tasklist. */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5157 | BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5158 | |
| 5159 | /* Cannot have done final schedule yet: would have vanished. */ |
Oleg Nesterov | c394cc9 | 2006-09-29 02:01:11 -0700 | [diff] [blame] | 5160 | BUG_ON(p->state == TASK_DEAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5161 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5162 | get_task_struct(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5163 | |
| 5164 | /* |
| 5165 | * Drop lock around migration; if someone else moves it, |
| 5166 | * that's OK. No task can be added to this CPU, so iteration is |
| 5167 | * fine. |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 5168 | * NOTE: interrupts should be left disabled --dev@ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5169 | */ |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 5170 | spin_unlock(&rq->lock); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5171 | move_task_off_dead_cpu(dead_cpu, p); |
Kirill Korotaev | 054b910 | 2006-12-10 02:20:11 -0800 | [diff] [blame] | 5172 | spin_lock(&rq->lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5173 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5174 | put_task_struct(p); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5175 | } |
| 5176 | |
| 5177 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ |
| 5178 | static void migrate_dead_tasks(unsigned int dead_cpu) |
| 5179 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5180 | struct rq *rq = cpu_rq(dead_cpu); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5181 | struct task_struct *next; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5182 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5183 | for ( ; ; ) { |
| 5184 | if (!rq->nr_running) |
| 5185 | break; |
| 5186 | next = pick_next_task(rq, rq->curr, rq_clock(rq)); |
| 5187 | if (!next) |
| 5188 | break; |
| 5189 | migrate_dead(dead_cpu, next); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5190 | } |
| 5191 | } |
| 5192 | #endif /* CONFIG_HOTPLUG_CPU */ |
| 5193 | |
| 5194 | /* |
| 5195 | * migration_call - callback that gets triggered when a CPU is added. |
| 5196 | * Here we can start up the necessary migration thread for the new CPU. |
| 5197 | */ |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5198 | static int __cpuinit |
| 5199 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5200 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5201 | struct task_struct *p; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5202 | int cpu = (long)hcpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5203 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5204 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5205 | |
| 5206 | switch (action) { |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 5207 | case CPU_LOCK_ACQUIRE: |
| 5208 | mutex_lock(&sched_hotcpu_mutex); |
| 5209 | break; |
| 5210 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5211 | case CPU_UP_PREPARE: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 5212 | case CPU_UP_PREPARE_FROZEN: |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5213 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5214 | if (IS_ERR(p)) |
| 5215 | return NOTIFY_BAD; |
| 5216 | p->flags |= PF_NOFREEZE; |
| 5217 | kthread_bind(p, cpu); |
| 5218 | /* Must be high prio: stop_machine expects to yield to it. */ |
| 5219 | rq = task_rq_lock(p, &flags); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5220 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5221 | task_rq_unlock(rq, &flags); |
| 5222 | cpu_rq(cpu)->migration_thread = p; |
| 5223 | break; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5224 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5225 | case CPU_ONLINE: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 5226 | case CPU_ONLINE_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5227 | /* Strictly unneccessary, as first user will wake it. */ |
| 5228 | wake_up_process(cpu_rq(cpu)->migration_thread); |
| 5229 | break; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5230 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5231 | #ifdef CONFIG_HOTPLUG_CPU |
| 5232 | case CPU_UP_CANCELED: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 5233 | case CPU_UP_CANCELED_FROZEN: |
Heiko Carstens | fc75cdf | 2006-06-25 05:49:10 -0700 | [diff] [blame] | 5234 | if (!cpu_rq(cpu)->migration_thread) |
| 5235 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5236 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
Heiko Carstens | a4c4af7 | 2005-11-07 00:58:38 -0800 | [diff] [blame] | 5237 | kthread_bind(cpu_rq(cpu)->migration_thread, |
| 5238 | any_online_cpu(cpu_online_map)); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5239 | kthread_stop(cpu_rq(cpu)->migration_thread); |
| 5240 | cpu_rq(cpu)->migration_thread = NULL; |
| 5241 | break; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5242 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5243 | case CPU_DEAD: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 5244 | case CPU_DEAD_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5245 | migrate_live_tasks(cpu); |
| 5246 | rq = cpu_rq(cpu); |
| 5247 | kthread_stop(rq->migration_thread); |
| 5248 | rq->migration_thread = NULL; |
| 5249 | /* Idle task back to normal (off runqueue, low prio) */ |
| 5250 | rq = task_rq_lock(rq->idle, &flags); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5251 | deactivate_task(rq, rq->idle, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5252 | rq->idle->static_prio = MAX_PRIO; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5253 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
| 5254 | rq->idle->sched_class = &idle_sched_class; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5255 | migrate_dead_tasks(cpu); |
| 5256 | task_rq_unlock(rq, &flags); |
| 5257 | migrate_nr_uninterruptible(rq); |
| 5258 | BUG_ON(rq->nr_running != 0); |
| 5259 | |
| 5260 | /* No need to migrate the tasks: it was best-effort if |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 5261 | * they didn't take sched_hotcpu_mutex. Just wake up |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5262 | * the requestors. */ |
| 5263 | spin_lock_irq(&rq->lock); |
| 5264 | while (!list_empty(&rq->migration_queue)) { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5265 | struct migration_req *req; |
| 5266 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5267 | req = list_entry(rq->migration_queue.next, |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5268 | struct migration_req, list); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5269 | list_del_init(&req->list); |
| 5270 | complete(&req->done); |
| 5271 | } |
| 5272 | spin_unlock_irq(&rq->lock); |
| 5273 | break; |
| 5274 | #endif |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 5275 | case CPU_LOCK_RELEASE: |
| 5276 | mutex_unlock(&sched_hotcpu_mutex); |
| 5277 | break; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5278 | } |
| 5279 | return NOTIFY_OK; |
| 5280 | } |
| 5281 | |
| 5282 | /* Register at highest priority so that task migration (migrate_all_tasks) |
| 5283 | * happens before everything else. |
| 5284 | */ |
Chandra Seetharaman | 26c2143 | 2006-06-27 02:54:10 -0700 | [diff] [blame] | 5285 | static struct notifier_block __cpuinitdata migration_notifier = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5286 | .notifier_call = migration_call, |
| 5287 | .priority = 10 |
| 5288 | }; |
| 5289 | |
| 5290 | int __init migration_init(void) |
| 5291 | { |
| 5292 | void *cpu = (void *)(long)smp_processor_id(); |
Akinobu Mita | 07dccf3 | 2006-09-29 02:00:22 -0700 | [diff] [blame] | 5293 | int err; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5294 | |
| 5295 | /* Start one for the boot CPU: */ |
Akinobu Mita | 07dccf3 | 2006-09-29 02:00:22 -0700 | [diff] [blame] | 5296 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
| 5297 | BUG_ON(err == NOTIFY_BAD); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5298 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
| 5299 | register_cpu_notifier(&migration_notifier); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5300 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5301 | return 0; |
| 5302 | } |
| 5303 | #endif |
| 5304 | |
| 5305 | #ifdef CONFIG_SMP |
Christoph Lameter | 476f353 | 2007-05-06 14:48:58 -0700 | [diff] [blame] | 5306 | |
| 5307 | /* Number of possible processor ids */ |
| 5308 | int nr_cpu_ids __read_mostly = NR_CPUS; |
| 5309 | EXPORT_SYMBOL(nr_cpu_ids); |
| 5310 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5311 | #undef SCHED_DOMAIN_DEBUG |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5312 | #ifdef SCHED_DOMAIN_DEBUG |
| 5313 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
| 5314 | { |
| 5315 | int level = 0; |
| 5316 | |
Nick Piggin | 41c7ce9 | 2005-06-25 14:57:24 -0700 | [diff] [blame] | 5317 | if (!sd) { |
| 5318 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); |
| 5319 | return; |
| 5320 | } |
| 5321 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5322 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
| 5323 | |
| 5324 | do { |
| 5325 | int i; |
| 5326 | char str[NR_CPUS]; |
| 5327 | struct sched_group *group = sd->groups; |
| 5328 | cpumask_t groupmask; |
| 5329 | |
| 5330 | cpumask_scnprintf(str, NR_CPUS, sd->span); |
| 5331 | cpus_clear(groupmask); |
| 5332 | |
| 5333 | printk(KERN_DEBUG); |
| 5334 | for (i = 0; i < level + 1; i++) |
| 5335 | printk(" "); |
| 5336 | printk("domain %d: ", level); |
| 5337 | |
| 5338 | if (!(sd->flags & SD_LOAD_BALANCE)) { |
| 5339 | printk("does not load-balance\n"); |
| 5340 | if (sd->parent) |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5341 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
| 5342 | " has parent"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5343 | break; |
| 5344 | } |
| 5345 | |
| 5346 | printk("span %s\n", str); |
| 5347 | |
| 5348 | if (!cpu_isset(cpu, sd->span)) |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5349 | printk(KERN_ERR "ERROR: domain->span does not contain " |
| 5350 | "CPU%d\n", cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5351 | if (!cpu_isset(cpu, group->cpumask)) |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5352 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
| 5353 | " CPU%d\n", cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5354 | |
| 5355 | printk(KERN_DEBUG); |
| 5356 | for (i = 0; i < level + 2; i++) |
| 5357 | printk(" "); |
| 5358 | printk("groups:"); |
| 5359 | do { |
| 5360 | if (!group) { |
| 5361 | printk("\n"); |
| 5362 | printk(KERN_ERR "ERROR: group is NULL\n"); |
| 5363 | break; |
| 5364 | } |
| 5365 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5366 | if (!group->__cpu_power) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5367 | printk("\n"); |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5368 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
| 5369 | "set\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5370 | } |
| 5371 | |
| 5372 | if (!cpus_weight(group->cpumask)) { |
| 5373 | printk("\n"); |
| 5374 | printk(KERN_ERR "ERROR: empty group\n"); |
| 5375 | } |
| 5376 | |
| 5377 | if (cpus_intersects(groupmask, group->cpumask)) { |
| 5378 | printk("\n"); |
| 5379 | printk(KERN_ERR "ERROR: repeated CPUs\n"); |
| 5380 | } |
| 5381 | |
| 5382 | cpus_or(groupmask, groupmask, group->cpumask); |
| 5383 | |
| 5384 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); |
| 5385 | printk(" %s", str); |
| 5386 | |
| 5387 | group = group->next; |
| 5388 | } while (group != sd->groups); |
| 5389 | printk("\n"); |
| 5390 | |
| 5391 | if (!cpus_equal(sd->span, groupmask)) |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5392 | printk(KERN_ERR "ERROR: groups don't span " |
| 5393 | "domain->span\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5394 | |
| 5395 | level++; |
| 5396 | sd = sd->parent; |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5397 | if (!sd) |
| 5398 | continue; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5399 | |
Miguel Ojeda Sandonis | 33859f7 | 2006-12-10 02:20:38 -0800 | [diff] [blame] | 5400 | if (!cpus_subset(groupmask, sd->span)) |
| 5401 | printk(KERN_ERR "ERROR: parent span is not a superset " |
| 5402 | "of domain->span\n"); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5403 | |
| 5404 | } while (sd); |
| 5405 | } |
| 5406 | #else |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5407 | # define sched_domain_debug(sd, cpu) do { } while (0) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5408 | #endif |
| 5409 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5410 | static int sd_degenerate(struct sched_domain *sd) |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5411 | { |
| 5412 | if (cpus_weight(sd->span) == 1) |
| 5413 | return 1; |
| 5414 | |
| 5415 | /* Following flags need at least 2 groups */ |
| 5416 | if (sd->flags & (SD_LOAD_BALANCE | |
| 5417 | SD_BALANCE_NEWIDLE | |
| 5418 | SD_BALANCE_FORK | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5419 | SD_BALANCE_EXEC | |
| 5420 | SD_SHARE_CPUPOWER | |
| 5421 | SD_SHARE_PKG_RESOURCES)) { |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5422 | if (sd->groups != sd->groups->next) |
| 5423 | return 0; |
| 5424 | } |
| 5425 | |
| 5426 | /* Following flags don't use groups */ |
| 5427 | if (sd->flags & (SD_WAKE_IDLE | |
| 5428 | SD_WAKE_AFFINE | |
| 5429 | SD_WAKE_BALANCE)) |
| 5430 | return 0; |
| 5431 | |
| 5432 | return 1; |
| 5433 | } |
| 5434 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5435 | static int |
| 5436 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5437 | { |
| 5438 | unsigned long cflags = sd->flags, pflags = parent->flags; |
| 5439 | |
| 5440 | if (sd_degenerate(parent)) |
| 5441 | return 1; |
| 5442 | |
| 5443 | if (!cpus_equal(sd->span, parent->span)) |
| 5444 | return 0; |
| 5445 | |
| 5446 | /* Does parent contain flags not in child? */ |
| 5447 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ |
| 5448 | if (cflags & SD_WAKE_AFFINE) |
| 5449 | pflags &= ~SD_WAKE_BALANCE; |
| 5450 | /* Flags needing groups don't count if only 1 group in parent */ |
| 5451 | if (parent->groups == parent->groups->next) { |
| 5452 | pflags &= ~(SD_LOAD_BALANCE | |
| 5453 | SD_BALANCE_NEWIDLE | |
| 5454 | SD_BALANCE_FORK | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5455 | SD_BALANCE_EXEC | |
| 5456 | SD_SHARE_CPUPOWER | |
| 5457 | SD_SHARE_PKG_RESOURCES); |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5458 | } |
| 5459 | if (~cflags & pflags) |
| 5460 | return 0; |
| 5461 | |
| 5462 | return 1; |
| 5463 | } |
| 5464 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5465 | /* |
| 5466 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
| 5467 | * hold the hotplug lock. |
| 5468 | */ |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5469 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5470 | { |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 5471 | struct rq *rq = cpu_rq(cpu); |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5472 | struct sched_domain *tmp; |
| 5473 | |
| 5474 | /* Remove the sched domains which do not contribute to scheduling. */ |
| 5475 | for (tmp = sd; tmp; tmp = tmp->parent) { |
| 5476 | struct sched_domain *parent = tmp->parent; |
| 5477 | if (!parent) |
| 5478 | break; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5479 | if (sd_parent_degenerate(tmp, parent)) { |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5480 | tmp->parent = parent->parent; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5481 | if (parent->parent) |
| 5482 | parent->parent->child = tmp; |
| 5483 | } |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5484 | } |
| 5485 | |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5486 | if (sd && sd_degenerate(sd)) { |
Suresh Siddha | 245af2c | 2005-06-25 14:57:25 -0700 | [diff] [blame] | 5487 | sd = sd->parent; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5488 | if (sd) |
| 5489 | sd->child = NULL; |
| 5490 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5491 | |
| 5492 | sched_domain_debug(sd, cpu); |
| 5493 | |
Nick Piggin | 674311d | 2005-06-25 14:57:27 -0700 | [diff] [blame] | 5494 | rcu_assign_pointer(rq->sd, sd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5495 | } |
| 5496 | |
| 5497 | /* cpus with isolated domains */ |
Tim Chen | 67af63a | 2006-12-22 01:07:50 -0800 | [diff] [blame] | 5498 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5499 | |
| 5500 | /* Setup the mask of cpus configured for isolated domains */ |
| 5501 | static int __init isolated_cpu_setup(char *str) |
| 5502 | { |
| 5503 | int ints[NR_CPUS], i; |
| 5504 | |
| 5505 | str = get_options(str, ARRAY_SIZE(ints), ints); |
| 5506 | cpus_clear(cpu_isolated_map); |
| 5507 | for (i = 1; i <= ints[0]; i++) |
| 5508 | if (ints[i] < NR_CPUS) |
| 5509 | cpu_set(ints[i], cpu_isolated_map); |
| 5510 | return 1; |
| 5511 | } |
| 5512 | |
| 5513 | __setup ("isolcpus=", isolated_cpu_setup); |
| 5514 | |
| 5515 | /* |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5516 | * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
| 5517 | * to a function which identifies what group(along with sched group) a CPU |
| 5518 | * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS |
| 5519 | * (due to the fact that we keep track of groups covered with a cpumask_t). |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5520 | * |
| 5521 | * init_sched_build_groups will build a circular linked list of the groups |
| 5522 | * covered by the given span, and will set each group's ->cpumask correctly, |
| 5523 | * and ->cpu_power to 0. |
| 5524 | */ |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5525 | static void |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5526 | init_sched_build_groups(cpumask_t span, const cpumask_t *cpu_map, |
| 5527 | int (*group_fn)(int cpu, const cpumask_t *cpu_map, |
| 5528 | struct sched_group **sg)) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5529 | { |
| 5530 | struct sched_group *first = NULL, *last = NULL; |
| 5531 | cpumask_t covered = CPU_MASK_NONE; |
| 5532 | int i; |
| 5533 | |
| 5534 | for_each_cpu_mask(i, span) { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5535 | struct sched_group *sg; |
| 5536 | int group = group_fn(i, cpu_map, &sg); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5537 | int j; |
| 5538 | |
| 5539 | if (cpu_isset(i, covered)) |
| 5540 | continue; |
| 5541 | |
| 5542 | sg->cpumask = CPU_MASK_NONE; |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5543 | sg->__cpu_power = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5544 | |
| 5545 | for_each_cpu_mask(j, span) { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5546 | if (group_fn(j, cpu_map, NULL) != group) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5547 | continue; |
| 5548 | |
| 5549 | cpu_set(j, covered); |
| 5550 | cpu_set(j, sg->cpumask); |
| 5551 | } |
| 5552 | if (!first) |
| 5553 | first = sg; |
| 5554 | if (last) |
| 5555 | last->next = sg; |
| 5556 | last = sg; |
| 5557 | } |
| 5558 | last->next = first; |
| 5559 | } |
| 5560 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5561 | #define SD_NODES_PER_DOMAIN 16 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5562 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5563 | #ifdef CONFIG_NUMA |
akpm@osdl.org | 198e2f1 | 2006-01-12 01:05:30 -0800 | [diff] [blame] | 5564 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5565 | /** |
| 5566 | * find_next_best_node - find the next node to include in a sched_domain |
| 5567 | * @node: node whose sched_domain we're building |
| 5568 | * @used_nodes: nodes already in the sched_domain |
| 5569 | * |
| 5570 | * Find the next node to include in a given scheduling domain. Simply |
| 5571 | * finds the closest node not already in the @used_nodes map. |
| 5572 | * |
| 5573 | * Should use nodemask_t. |
| 5574 | */ |
| 5575 | static int find_next_best_node(int node, unsigned long *used_nodes) |
| 5576 | { |
| 5577 | int i, n, val, min_val, best_node = 0; |
| 5578 | |
| 5579 | min_val = INT_MAX; |
| 5580 | |
| 5581 | for (i = 0; i < MAX_NUMNODES; i++) { |
| 5582 | /* Start at @node */ |
| 5583 | n = (node + i) % MAX_NUMNODES; |
| 5584 | |
| 5585 | if (!nr_cpus_node(n)) |
| 5586 | continue; |
| 5587 | |
| 5588 | /* Skip already used nodes */ |
| 5589 | if (test_bit(n, used_nodes)) |
| 5590 | continue; |
| 5591 | |
| 5592 | /* Simple min distance search */ |
| 5593 | val = node_distance(node, n); |
| 5594 | |
| 5595 | if (val < min_val) { |
| 5596 | min_val = val; |
| 5597 | best_node = n; |
| 5598 | } |
| 5599 | } |
| 5600 | |
| 5601 | set_bit(best_node, used_nodes); |
| 5602 | return best_node; |
| 5603 | } |
| 5604 | |
| 5605 | /** |
| 5606 | * sched_domain_node_span - get a cpumask for a node's sched_domain |
| 5607 | * @node: node whose cpumask we're constructing |
| 5608 | * @size: number of nodes to include in this span |
| 5609 | * |
| 5610 | * Given a node, construct a good cpumask for its sched_domain to span. It |
| 5611 | * should be one that prevents unnecessary balancing, but also spreads tasks |
| 5612 | * out optimally. |
| 5613 | */ |
| 5614 | static cpumask_t sched_domain_node_span(int node) |
| 5615 | { |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5616 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5617 | cpumask_t span, nodemask; |
| 5618 | int i; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5619 | |
| 5620 | cpus_clear(span); |
| 5621 | bitmap_zero(used_nodes, MAX_NUMNODES); |
| 5622 | |
| 5623 | nodemask = node_to_cpumask(node); |
| 5624 | cpus_or(span, span, nodemask); |
| 5625 | set_bit(node, used_nodes); |
| 5626 | |
| 5627 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { |
| 5628 | int next_node = find_next_best_node(node, used_nodes); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5629 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5630 | nodemask = node_to_cpumask(next_node); |
| 5631 | cpus_or(span, span, nodemask); |
| 5632 | } |
| 5633 | |
| 5634 | return span; |
| 5635 | } |
| 5636 | #endif |
| 5637 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 5638 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5639 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5640 | /* |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5641 | * SMT sched-domains: |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5642 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5643 | #ifdef CONFIG_SCHED_SMT |
| 5644 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5645 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5646 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5647 | static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, |
| 5648 | struct sched_group **sg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5649 | { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5650 | if (sg) |
| 5651 | *sg = &per_cpu(sched_group_cpus, cpu); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5652 | return cpu; |
| 5653 | } |
| 5654 | #endif |
| 5655 | |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5656 | /* |
| 5657 | * multi-core sched-domains: |
| 5658 | */ |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5659 | #ifdef CONFIG_SCHED_MC |
| 5660 | static DEFINE_PER_CPU(struct sched_domain, core_domains); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5661 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5662 | #endif |
| 5663 | |
| 5664 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5665 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
| 5666 | struct sched_group **sg) |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5667 | { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5668 | int group; |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5669 | cpumask_t mask = cpu_sibling_map[cpu]; |
| 5670 | cpus_and(mask, mask, *cpu_map); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5671 | group = first_cpu(mask); |
| 5672 | if (sg) |
| 5673 | *sg = &per_cpu(sched_group_core, group); |
| 5674 | return group; |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5675 | } |
| 5676 | #elif defined(CONFIG_SCHED_MC) |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5677 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
| 5678 | struct sched_group **sg) |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5679 | { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5680 | if (sg) |
| 5681 | *sg = &per_cpu(sched_group_core, cpu); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5682 | return cpu; |
| 5683 | } |
| 5684 | #endif |
| 5685 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5686 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5687 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5688 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5689 | static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, |
| 5690 | struct sched_group **sg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5691 | { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5692 | int group; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 5693 | #ifdef CONFIG_SCHED_MC |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5694 | cpumask_t mask = cpu_coregroup_map(cpu); |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5695 | cpus_and(mask, mask, *cpu_map); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5696 | group = first_cpu(mask); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5697 | #elif defined(CONFIG_SCHED_SMT) |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5698 | cpumask_t mask = cpu_sibling_map[cpu]; |
| 5699 | cpus_and(mask, mask, *cpu_map); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5700 | group = first_cpu(mask); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5701 | #else |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5702 | group = cpu; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5703 | #endif |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5704 | if (sg) |
| 5705 | *sg = &per_cpu(sched_group_phys, group); |
| 5706 | return group; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5707 | } |
| 5708 | |
| 5709 | #ifdef CONFIG_NUMA |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5710 | /* |
| 5711 | * The init_sched_build_groups can't handle what we want to do with node |
| 5712 | * groups, so roll our own. Now each node has its own list of groups which |
| 5713 | * gets dynamically allocated. |
| 5714 | */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5715 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5716 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5717 | |
| 5718 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5719 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5720 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5721 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
| 5722 | struct sched_group **sg) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5723 | { |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5724 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(cpu)); |
| 5725 | int group; |
| 5726 | |
| 5727 | cpus_and(nodemask, nodemask, *cpu_map); |
| 5728 | group = first_cpu(nodemask); |
| 5729 | |
| 5730 | if (sg) |
| 5731 | *sg = &per_cpu(sched_group_allnodes, group); |
| 5732 | return group; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5733 | } |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5734 | |
Siddha, Suresh B | 0806903 | 2006-03-27 01:15:23 -0800 | [diff] [blame] | 5735 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
| 5736 | { |
| 5737 | struct sched_group *sg = group_head; |
| 5738 | int j; |
| 5739 | |
| 5740 | if (!sg) |
| 5741 | return; |
| 5742 | next_sg: |
| 5743 | for_each_cpu_mask(j, sg->cpumask) { |
| 5744 | struct sched_domain *sd; |
| 5745 | |
| 5746 | sd = &per_cpu(phys_domains, j); |
| 5747 | if (j != first_cpu(sd->groups->cpumask)) { |
| 5748 | /* |
| 5749 | * Only add "power" once for each |
| 5750 | * physical package. |
| 5751 | */ |
| 5752 | continue; |
| 5753 | } |
| 5754 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5755 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
Siddha, Suresh B | 0806903 | 2006-03-27 01:15:23 -0800 | [diff] [blame] | 5756 | } |
| 5757 | sg = sg->next; |
| 5758 | if (sg != group_head) |
| 5759 | goto next_sg; |
| 5760 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5761 | #endif |
| 5762 | |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5763 | #ifdef CONFIG_NUMA |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5764 | /* Free memory allocated for various sched_group structures */ |
| 5765 | static void free_sched_groups(const cpumask_t *cpu_map) |
| 5766 | { |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5767 | int cpu, i; |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5768 | |
| 5769 | for_each_cpu_mask(cpu, *cpu_map) { |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5770 | struct sched_group **sched_group_nodes |
| 5771 | = sched_group_nodes_bycpu[cpu]; |
| 5772 | |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5773 | if (!sched_group_nodes) |
| 5774 | continue; |
| 5775 | |
| 5776 | for (i = 0; i < MAX_NUMNODES; i++) { |
| 5777 | cpumask_t nodemask = node_to_cpumask(i); |
| 5778 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; |
| 5779 | |
| 5780 | cpus_and(nodemask, nodemask, *cpu_map); |
| 5781 | if (cpus_empty(nodemask)) |
| 5782 | continue; |
| 5783 | |
| 5784 | if (sg == NULL) |
| 5785 | continue; |
| 5786 | sg = sg->next; |
| 5787 | next_sg: |
| 5788 | oldsg = sg; |
| 5789 | sg = sg->next; |
| 5790 | kfree(oldsg); |
| 5791 | if (oldsg != sched_group_nodes[i]) |
| 5792 | goto next_sg; |
| 5793 | } |
| 5794 | kfree(sched_group_nodes); |
| 5795 | sched_group_nodes_bycpu[cpu] = NULL; |
| 5796 | } |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5797 | } |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 5798 | #else |
| 5799 | static void free_sched_groups(const cpumask_t *cpu_map) |
| 5800 | { |
| 5801 | } |
| 5802 | #endif |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5803 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5804 | /* |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5805 | * Initialize sched groups cpu_power. |
| 5806 | * |
| 5807 | * cpu_power indicates the capacity of sched group, which is used while |
| 5808 | * distributing the load between different sched groups in a sched domain. |
| 5809 | * Typically cpu_power for all the groups in a sched domain will be same unless |
| 5810 | * there are asymmetries in the topology. If there are asymmetries, group |
| 5811 | * having more cpu_power will pickup more load compared to the group having |
| 5812 | * less cpu_power. |
| 5813 | * |
| 5814 | * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents |
| 5815 | * the maximum number of tasks a group can handle in the presence of other idle |
| 5816 | * or lightly loaded groups in the same sched domain. |
| 5817 | */ |
| 5818 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) |
| 5819 | { |
| 5820 | struct sched_domain *child; |
| 5821 | struct sched_group *group; |
| 5822 | |
| 5823 | WARN_ON(!sd || !sd->groups); |
| 5824 | |
| 5825 | if (cpu != first_cpu(sd->groups->cpumask)) |
| 5826 | return; |
| 5827 | |
| 5828 | child = sd->child; |
| 5829 | |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5830 | sd->groups->__cpu_power = 0; |
| 5831 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5832 | /* |
| 5833 | * For perf policy, if the groups in child domain share resources |
| 5834 | * (for example cores sharing some portions of the cache hierarchy |
| 5835 | * or SMT), then set this domain groups cpu_power such that each group |
| 5836 | * can handle only one task, when there are other idle groups in the |
| 5837 | * same sched domain. |
| 5838 | */ |
| 5839 | if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && |
| 5840 | (child->flags & |
| 5841 | (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5842 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5843 | return; |
| 5844 | } |
| 5845 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5846 | /* |
| 5847 | * add cpu_power of each child group to this groups cpu_power |
| 5848 | */ |
| 5849 | group = child->groups; |
| 5850 | do { |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 5851 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 5852 | group = group->next; |
| 5853 | } while (group != child->groups); |
| 5854 | } |
| 5855 | |
| 5856 | /* |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5857 | * Build sched domains for a given set of cpus and attach the sched domains |
| 5858 | * to the individual cpus |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5859 | */ |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5860 | static int build_sched_domains(const cpumask_t *cpu_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5861 | { |
| 5862 | int i; |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5863 | #ifdef CONFIG_NUMA |
| 5864 | struct sched_group **sched_group_nodes = NULL; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5865 | int sd_allnodes = 0; |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5866 | |
| 5867 | /* |
| 5868 | * Allocate the per-node list of sched groups |
| 5869 | */ |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5870 | sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES, |
Srivatsa Vaddagiri | d3a5aa9 | 2006-06-27 02:54:39 -0700 | [diff] [blame] | 5871 | GFP_KERNEL); |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5872 | if (!sched_group_nodes) { |
| 5873 | printk(KERN_WARNING "Can not alloc sched group node list\n"); |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 5874 | return -ENOMEM; |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5875 | } |
| 5876 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; |
| 5877 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5878 | |
| 5879 | /* |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5880 | * Set up domains for cpus specified by the cpu_map. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5881 | */ |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5882 | for_each_cpu_mask(i, *cpu_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5883 | struct sched_domain *sd = NULL, *p; |
| 5884 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); |
| 5885 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5886 | cpus_and(nodemask, nodemask, *cpu_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5887 | |
| 5888 | #ifdef CONFIG_NUMA |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5889 | if (cpus_weight(*cpu_map) > |
| 5890 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5891 | sd = &per_cpu(allnodes_domains, i); |
| 5892 | *sd = SD_ALLNODES_INIT; |
| 5893 | sd->span = *cpu_map; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5894 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5895 | p = sd; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5896 | sd_allnodes = 1; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5897 | } else |
| 5898 | p = NULL; |
| 5899 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5900 | sd = &per_cpu(node_domains, i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5901 | *sd = SD_NODE_INIT; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5902 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
| 5903 | sd->parent = p; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5904 | if (p) |
| 5905 | p->child = sd; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5906 | cpus_and(sd->span, sd->span, *cpu_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5907 | #endif |
| 5908 | |
| 5909 | p = sd; |
| 5910 | sd = &per_cpu(phys_domains, i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5911 | *sd = SD_CPU_INIT; |
| 5912 | sd->span = nodemask; |
| 5913 | sd->parent = p; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5914 | if (p) |
| 5915 | p->child = sd; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5916 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5917 | |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5918 | #ifdef CONFIG_SCHED_MC |
| 5919 | p = sd; |
| 5920 | sd = &per_cpu(core_domains, i); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5921 | *sd = SD_MC_INIT; |
| 5922 | sd->span = cpu_coregroup_map(i); |
| 5923 | cpus_and(sd->span, sd->span, *cpu_map); |
| 5924 | sd->parent = p; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5925 | p->child = sd; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5926 | cpu_to_core_group(i, cpu_map, &sd->groups); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5927 | #endif |
| 5928 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5929 | #ifdef CONFIG_SCHED_SMT |
| 5930 | p = sd; |
| 5931 | sd = &per_cpu(cpu_domains, i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5932 | *sd = SD_SIBLING_INIT; |
| 5933 | sd->span = cpu_sibling_map[i]; |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5934 | cpus_and(sd->span, sd->span, *cpu_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5935 | sd->parent = p; |
Siddha, Suresh B | 1a84887 | 2006-10-03 01:14:08 -0700 | [diff] [blame] | 5936 | p->child = sd; |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5937 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5938 | #endif |
| 5939 | } |
| 5940 | |
| 5941 | #ifdef CONFIG_SCHED_SMT |
| 5942 | /* Set up CPU (sibling) groups */ |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5943 | for_each_cpu_mask(i, *cpu_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5944 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5945 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5946 | if (i != first_cpu(this_sibling_map)) |
| 5947 | continue; |
| 5948 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5949 | init_sched_build_groups(this_sibling_map, cpu_map, |
| 5950 | &cpu_to_cpu_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5951 | } |
| 5952 | #endif |
| 5953 | |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5954 | #ifdef CONFIG_SCHED_MC |
| 5955 | /* Set up multi-core groups */ |
| 5956 | for_each_cpu_mask(i, *cpu_map) { |
| 5957 | cpumask_t this_core_map = cpu_coregroup_map(i); |
| 5958 | cpus_and(this_core_map, this_core_map, *cpu_map); |
| 5959 | if (i != first_cpu(this_core_map)) |
| 5960 | continue; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5961 | init_sched_build_groups(this_core_map, cpu_map, |
| 5962 | &cpu_to_core_group); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 5963 | } |
| 5964 | #endif |
| 5965 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5966 | /* Set up physical groups */ |
| 5967 | for (i = 0; i < MAX_NUMNODES; i++) { |
| 5968 | cpumask_t nodemask = node_to_cpumask(i); |
| 5969 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 5970 | cpus_and(nodemask, nodemask, *cpu_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5971 | if (cpus_empty(nodemask)) |
| 5972 | continue; |
| 5973 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5974 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 5975 | } |
| 5976 | |
| 5977 | #ifdef CONFIG_NUMA |
| 5978 | /* Set up node groups */ |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 5979 | if (sd_allnodes) |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 5980 | init_sched_build_groups(*cpu_map, cpu_map, |
| 5981 | &cpu_to_allnodes_group); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5982 | |
| 5983 | for (i = 0; i < MAX_NUMNODES; i++) { |
| 5984 | /* Set up node groups */ |
| 5985 | struct sched_group *sg, *prev; |
| 5986 | cpumask_t nodemask = node_to_cpumask(i); |
| 5987 | cpumask_t domainspan; |
| 5988 | cpumask_t covered = CPU_MASK_NONE; |
| 5989 | int j; |
| 5990 | |
| 5991 | cpus_and(nodemask, nodemask, *cpu_map); |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5992 | if (cpus_empty(nodemask)) { |
| 5993 | sched_group_nodes[i] = NULL; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5994 | continue; |
John Hawkes | d1b5513 | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5995 | } |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 5996 | |
| 5997 | domainspan = sched_domain_node_span(i); |
| 5998 | cpus_and(domainspan, domainspan, *cpu_map); |
| 5999 | |
Srivatsa Vaddagiri | 15f0b67 | 2006-06-27 02:54:40 -0700 | [diff] [blame] | 6000 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6001 | if (!sg) { |
| 6002 | printk(KERN_WARNING "Can not alloc domain group for " |
| 6003 | "node %d\n", i); |
| 6004 | goto error; |
| 6005 | } |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6006 | sched_group_nodes[i] = sg; |
| 6007 | for_each_cpu_mask(j, nodemask) { |
| 6008 | struct sched_domain *sd; |
| 6009 | sd = &per_cpu(node_domains, j); |
| 6010 | sd->groups = sg; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6011 | } |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 6012 | sg->__cpu_power = 0; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6013 | sg->cpumask = nodemask; |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6014 | sg->next = sg; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6015 | cpus_or(covered, covered, nodemask); |
| 6016 | prev = sg; |
| 6017 | |
| 6018 | for (j = 0; j < MAX_NUMNODES; j++) { |
| 6019 | cpumask_t tmp, notcovered; |
| 6020 | int n = (i + j) % MAX_NUMNODES; |
| 6021 | |
| 6022 | cpus_complement(notcovered, covered); |
| 6023 | cpus_and(tmp, notcovered, *cpu_map); |
| 6024 | cpus_and(tmp, tmp, domainspan); |
| 6025 | if (cpus_empty(tmp)) |
| 6026 | break; |
| 6027 | |
| 6028 | nodemask = node_to_cpumask(n); |
| 6029 | cpus_and(tmp, tmp, nodemask); |
| 6030 | if (cpus_empty(tmp)) |
| 6031 | continue; |
| 6032 | |
Srivatsa Vaddagiri | 15f0b67 | 2006-06-27 02:54:40 -0700 | [diff] [blame] | 6033 | sg = kmalloc_node(sizeof(struct sched_group), |
| 6034 | GFP_KERNEL, i); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6035 | if (!sg) { |
| 6036 | printk(KERN_WARNING |
| 6037 | "Can not alloc domain group for node %d\n", j); |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6038 | goto error; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6039 | } |
Eric Dumazet | 5517d86 | 2007-05-08 00:32:57 -0700 | [diff] [blame] | 6040 | sg->__cpu_power = 0; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6041 | sg->cpumask = tmp; |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6042 | sg->next = prev->next; |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6043 | cpus_or(covered, covered, tmp); |
| 6044 | prev->next = sg; |
| 6045 | prev = sg; |
| 6046 | } |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6047 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6048 | #endif |
| 6049 | |
| 6050 | /* Calculate CPU power for physical packages and nodes */ |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6051 | #ifdef CONFIG_SCHED_SMT |
| 6052 | for_each_cpu_mask(i, *cpu_map) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6053 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
| 6054 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 6055 | init_sched_groups_power(i, sd); |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6056 | } |
| 6057 | #endif |
| 6058 | #ifdef CONFIG_SCHED_MC |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6059 | for_each_cpu_mask(i, *cpu_map) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6060 | struct sched_domain *sd = &per_cpu(core_domains, i); |
| 6061 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 6062 | init_sched_groups_power(i, sd); |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6063 | } |
| 6064 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6065 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6066 | for_each_cpu_mask(i, *cpu_map) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6067 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
| 6068 | |
Siddha, Suresh B | 89c4710 | 2006-10-03 01:14:09 -0700 | [diff] [blame] | 6069 | init_sched_groups_power(i, sd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6070 | } |
| 6071 | |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6072 | #ifdef CONFIG_NUMA |
Siddha, Suresh B | 0806903 | 2006-03-27 01:15:23 -0800 | [diff] [blame] | 6073 | for (i = 0; i < MAX_NUMNODES; i++) |
| 6074 | init_numa_sched_groups_power(sched_group_nodes[i]); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6075 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 6076 | if (sd_allnodes) { |
| 6077 | struct sched_group *sg; |
Siddha, Suresh B | f712c0c | 2006-07-30 03:02:59 -0700 | [diff] [blame] | 6078 | |
Siddha, Suresh B | 6711cab | 2006-12-10 02:20:07 -0800 | [diff] [blame] | 6079 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
Siddha, Suresh B | f712c0c | 2006-07-30 03:02:59 -0700 | [diff] [blame] | 6080 | init_numa_sched_groups_power(sg); |
| 6081 | } |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6082 | #endif |
| 6083 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6084 | /* Attach the domains */ |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6085 | for_each_cpu_mask(i, *cpu_map) { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6086 | struct sched_domain *sd; |
| 6087 | #ifdef CONFIG_SCHED_SMT |
| 6088 | sd = &per_cpu(cpu_domains, i); |
Siddha, Suresh B | 1e9f28f | 2006-03-27 01:15:22 -0800 | [diff] [blame] | 6089 | #elif defined(CONFIG_SCHED_MC) |
| 6090 | sd = &per_cpu(core_domains, i); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6091 | #else |
| 6092 | sd = &per_cpu(phys_domains, i); |
| 6093 | #endif |
| 6094 | cpu_attach_domain(sd, i); |
| 6095 | } |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6096 | |
| 6097 | return 0; |
| 6098 | |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 6099 | #ifdef CONFIG_NUMA |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6100 | error: |
| 6101 | free_sched_groups(cpu_map); |
| 6102 | return -ENOMEM; |
Siddha, Suresh B | a616058 | 2006-10-03 01:14:06 -0700 | [diff] [blame] | 6103 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6104 | } |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6105 | /* |
| 6106 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
| 6107 | */ |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6108 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6109 | { |
| 6110 | cpumask_t cpu_default_map; |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6111 | int err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6112 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6113 | /* |
| 6114 | * Setup mask for cpus without special case scheduling requirements. |
| 6115 | * For now this just excludes isolated cpus, but could be used to |
| 6116 | * exclude other special cases in the future. |
| 6117 | */ |
| 6118 | cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); |
| 6119 | |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6120 | err = build_sched_domains(&cpu_default_map); |
| 6121 | |
| 6122 | return err; |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6123 | } |
| 6124 | |
| 6125 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6126 | { |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6127 | free_sched_groups(cpu_map); |
John Hawkes | 9c1cfda | 2005-09-06 15:18:14 -0700 | [diff] [blame] | 6128 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6129 | |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6130 | /* |
| 6131 | * Detach sched domains from a group of cpus specified in cpu_map |
| 6132 | * These cpus will now be attached to the NULL domain |
| 6133 | */ |
Arjan van de Ven | 858119e | 2006-01-14 13:20:43 -0800 | [diff] [blame] | 6134 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6135 | { |
| 6136 | int i; |
| 6137 | |
| 6138 | for_each_cpu_mask(i, *cpu_map) |
| 6139 | cpu_attach_domain(NULL, i); |
| 6140 | synchronize_sched(); |
| 6141 | arch_destroy_sched_domains(cpu_map); |
| 6142 | } |
| 6143 | |
| 6144 | /* |
| 6145 | * Partition sched domains as specified by the cpumasks below. |
| 6146 | * This attaches all cpus from the cpumasks to the NULL domain, |
| 6147 | * waits for a RCU quiescent period, recalculates sched |
| 6148 | * domain information and then attaches them back to the |
| 6149 | * correct sched domains |
| 6150 | * Call with hotplug lock held |
| 6151 | */ |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6152 | int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6153 | { |
| 6154 | cpumask_t change_map; |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6155 | int err = 0; |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6156 | |
| 6157 | cpus_and(*partition1, *partition1, cpu_online_map); |
| 6158 | cpus_and(*partition2, *partition2, cpu_online_map); |
| 6159 | cpus_or(change_map, *partition1, *partition2); |
| 6160 | |
| 6161 | /* Detach sched domains from all of the affected cpus */ |
| 6162 | detach_destroy_domains(&change_map); |
| 6163 | if (!cpus_empty(*partition1)) |
Srivatsa Vaddagiri | 51888ca | 2006-06-27 02:54:38 -0700 | [diff] [blame] | 6164 | err = build_sched_domains(partition1); |
| 6165 | if (!err && !cpus_empty(*partition2)) |
| 6166 | err = build_sched_domains(partition2); |
| 6167 | |
| 6168 | return err; |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6169 | } |
| 6170 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6171 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| 6172 | int arch_reinit_sched_domains(void) |
| 6173 | { |
| 6174 | int err; |
| 6175 | |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 6176 | mutex_lock(&sched_hotcpu_mutex); |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6177 | detach_destroy_domains(&cpu_online_map); |
| 6178 | err = arch_init_sched_domains(&cpu_online_map); |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 6179 | mutex_unlock(&sched_hotcpu_mutex); |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6180 | |
| 6181 | return err; |
| 6182 | } |
| 6183 | |
| 6184 | static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) |
| 6185 | { |
| 6186 | int ret; |
| 6187 | |
| 6188 | if (buf[0] != '0' && buf[0] != '1') |
| 6189 | return -EINVAL; |
| 6190 | |
| 6191 | if (smt) |
| 6192 | sched_smt_power_savings = (buf[0] == '1'); |
| 6193 | else |
| 6194 | sched_mc_power_savings = (buf[0] == '1'); |
| 6195 | |
| 6196 | ret = arch_reinit_sched_domains(); |
| 6197 | |
| 6198 | return ret ? ret : count; |
| 6199 | } |
| 6200 | |
| 6201 | int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) |
| 6202 | { |
| 6203 | int err = 0; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 6204 | |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6205 | #ifdef CONFIG_SCHED_SMT |
| 6206 | if (smt_capable()) |
| 6207 | err = sysfs_create_file(&cls->kset.kobj, |
| 6208 | &attr_sched_smt_power_savings.attr); |
| 6209 | #endif |
| 6210 | #ifdef CONFIG_SCHED_MC |
| 6211 | if (!err && mc_capable()) |
| 6212 | err = sysfs_create_file(&cls->kset.kobj, |
| 6213 | &attr_sched_mc_power_savings.attr); |
| 6214 | #endif |
| 6215 | return err; |
| 6216 | } |
| 6217 | #endif |
| 6218 | |
| 6219 | #ifdef CONFIG_SCHED_MC |
| 6220 | static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) |
| 6221 | { |
| 6222 | return sprintf(page, "%u\n", sched_mc_power_savings); |
| 6223 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 6224 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
| 6225 | const char *buf, size_t count) |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6226 | { |
| 6227 | return sched_power_savings_store(buf, count, 0); |
| 6228 | } |
| 6229 | SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
| 6230 | sched_mc_power_savings_store); |
| 6231 | #endif |
| 6232 | |
| 6233 | #ifdef CONFIG_SCHED_SMT |
| 6234 | static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) |
| 6235 | { |
| 6236 | return sprintf(page, "%u\n", sched_smt_power_savings); |
| 6237 | } |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 6238 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
| 6239 | const char *buf, size_t count) |
Siddha, Suresh B | 5c45bf2 | 2006-06-27 02:54:42 -0700 | [diff] [blame] | 6240 | { |
| 6241 | return sched_power_savings_store(buf, count, 1); |
| 6242 | } |
| 6243 | SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
| 6244 | sched_smt_power_savings_store); |
| 6245 | #endif |
| 6246 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6247 | /* |
| 6248 | * Force a reinitialization of the sched domains hierarchy. The domains |
| 6249 | * and groups cannot be updated in place without racing with the balancing |
Nick Piggin | 41c7ce9 | 2005-06-25 14:57:24 -0700 | [diff] [blame] | 6250 | * code, so we temporarily attach all running cpus to the NULL domain |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6251 | * which will prevent rebalancing while the sched domains are recalculated. |
| 6252 | */ |
| 6253 | static int update_sched_domains(struct notifier_block *nfb, |
| 6254 | unsigned long action, void *hcpu) |
| 6255 | { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6256 | switch (action) { |
| 6257 | case CPU_UP_PREPARE: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6258 | case CPU_UP_PREPARE_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6259 | case CPU_DOWN_PREPARE: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6260 | case CPU_DOWN_PREPARE_FROZEN: |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6261 | detach_destroy_domains(&cpu_online_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6262 | return NOTIFY_OK; |
| 6263 | |
| 6264 | case CPU_UP_CANCELED: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6265 | case CPU_UP_CANCELED_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6266 | case CPU_DOWN_FAILED: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6267 | case CPU_DOWN_FAILED_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6268 | case CPU_ONLINE: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6269 | case CPU_ONLINE_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6270 | case CPU_DEAD: |
Rafael J. Wysocki | 8bb7844 | 2007-05-09 02:35:10 -0700 | [diff] [blame] | 6271 | case CPU_DEAD_FROZEN: |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6272 | /* |
| 6273 | * Fall through and re-initialise the domains. |
| 6274 | */ |
| 6275 | break; |
| 6276 | default: |
| 6277 | return NOTIFY_DONE; |
| 6278 | } |
| 6279 | |
| 6280 | /* The hotplug lock is already held by cpu_up/cpu_down */ |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6281 | arch_init_sched_domains(&cpu_online_map); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6282 | |
| 6283 | return NOTIFY_OK; |
| 6284 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6285 | |
| 6286 | void __init sched_init_smp(void) |
| 6287 | { |
Nick Piggin | 5c1e176 | 2006-10-03 01:14:04 -0700 | [diff] [blame] | 6288 | cpumask_t non_isolated_cpus; |
| 6289 | |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 6290 | mutex_lock(&sched_hotcpu_mutex); |
Dinakar Guniguntala | 1a20ff2 | 2005-06-25 14:57:33 -0700 | [diff] [blame] | 6291 | arch_init_sched_domains(&cpu_online_map); |
Nathan Lynch | e5e5673 | 2007-01-10 23:15:28 -0800 | [diff] [blame] | 6292 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
Nick Piggin | 5c1e176 | 2006-10-03 01:14:04 -0700 | [diff] [blame] | 6293 | if (cpus_empty(non_isolated_cpus)) |
| 6294 | cpu_set(smp_processor_id(), non_isolated_cpus); |
Gautham R Shenoy | 5be9361 | 2007-05-09 02:34:04 -0700 | [diff] [blame] | 6295 | mutex_unlock(&sched_hotcpu_mutex); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6296 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
| 6297 | hotcpu_notifier(update_sched_domains, 0); |
Nick Piggin | 5c1e176 | 2006-10-03 01:14:04 -0700 | [diff] [blame] | 6298 | |
| 6299 | /* Move init over to a non-isolated CPU */ |
| 6300 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) |
| 6301 | BUG(); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6302 | sched_init_granularity(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6303 | } |
| 6304 | #else |
| 6305 | void __init sched_init_smp(void) |
| 6306 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6307 | sched_init_granularity(); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6308 | } |
| 6309 | #endif /* CONFIG_SMP */ |
| 6310 | |
| 6311 | int in_sched_functions(unsigned long addr) |
| 6312 | { |
| 6313 | /* Linker adds these: start and end of __sched functions */ |
| 6314 | extern char __sched_text_start[], __sched_text_end[]; |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 6315 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6316 | return in_lock_functions(addr) || |
| 6317 | (addr >= (unsigned long)__sched_text_start |
| 6318 | && addr < (unsigned long)__sched_text_end); |
| 6319 | } |
| 6320 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6321 | static inline void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
| 6322 | { |
| 6323 | cfs_rq->tasks_timeline = RB_ROOT; |
| 6324 | cfs_rq->fair_clock = 1; |
| 6325 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 6326 | cfs_rq->rq = rq; |
| 6327 | #endif |
| 6328 | } |
| 6329 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6330 | void __init sched_init(void) |
| 6331 | { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6332 | u64 now = sched_clock(); |
Christoph Lameter | 476f353 | 2007-05-06 14:48:58 -0700 | [diff] [blame] | 6333 | int highest_cpu = 0; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6334 | int i, j; |
| 6335 | |
| 6336 | /* |
| 6337 | * Link up the scheduling class hierarchy: |
| 6338 | */ |
| 6339 | rt_sched_class.next = &fair_sched_class; |
| 6340 | fair_sched_class.next = &idle_sched_class; |
| 6341 | idle_sched_class.next = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6342 | |
KAMEZAWA Hiroyuki | 0a94502 | 2006-03-28 01:56:37 -0800 | [diff] [blame] | 6343 | for_each_possible_cpu(i) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6344 | struct rt_prio_array *array; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 6345 | struct rq *rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6346 | |
| 6347 | rq = cpu_rq(i); |
| 6348 | spin_lock_init(&rq->lock); |
Ingo Molnar | fcb9937 | 2006-07-03 00:25:10 -0700 | [diff] [blame] | 6349 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
Nick Piggin | 7897986 | 2005-06-25 14:57:13 -0700 | [diff] [blame] | 6350 | rq->nr_running = 0; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6351 | rq->clock = 1; |
| 6352 | init_cfs_rq(&rq->cfs, rq); |
| 6353 | #ifdef CONFIG_FAIR_GROUP_SCHED |
| 6354 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
| 6355 | list_add(&rq->cfs.leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); |
| 6356 | #endif |
| 6357 | rq->ls.load_update_last = now; |
| 6358 | rq->ls.load_update_start = now; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6359 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6360 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
| 6361 | rq->cpu_load[j] = 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6362 | #ifdef CONFIG_SMP |
Nick Piggin | 41c7ce9 | 2005-06-25 14:57:24 -0700 | [diff] [blame] | 6363 | rq->sd = NULL; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6364 | rq->active_balance = 0; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6365 | rq->next_balance = jiffies; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6366 | rq->push_cpu = 0; |
Christoph Lameter | 0a2966b | 2006-09-25 23:30:51 -0700 | [diff] [blame] | 6367 | rq->cpu = i; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6368 | rq->migration_thread = NULL; |
| 6369 | INIT_LIST_HEAD(&rq->migration_queue); |
| 6370 | #endif |
| 6371 | atomic_set(&rq->nr_iowait, 0); |
| 6372 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6373 | array = &rq->rt.active; |
| 6374 | for (j = 0; j < MAX_RT_PRIO; j++) { |
| 6375 | INIT_LIST_HEAD(array->queue + j); |
| 6376 | __clear_bit(j, array->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6377 | } |
Christoph Lameter | 476f353 | 2007-05-06 14:48:58 -0700 | [diff] [blame] | 6378 | highest_cpu = i; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6379 | /* delimiter for bitsearch: */ |
| 6380 | __set_bit(MAX_RT_PRIO, array->bitmap); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6381 | } |
| 6382 | |
Peter Williams | 2dd73a4 | 2006-06-27 02:54:34 -0700 | [diff] [blame] | 6383 | set_load_weight(&init_task); |
Heiko Carstens | b50f60c | 2006-07-30 03:03:52 -0700 | [diff] [blame] | 6384 | |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 6385 | #ifdef CONFIG_SMP |
Christoph Lameter | 476f353 | 2007-05-06 14:48:58 -0700 | [diff] [blame] | 6386 | nr_cpu_ids = highest_cpu + 1; |
Christoph Lameter | c9819f4 | 2006-12-10 02:20:25 -0800 | [diff] [blame] | 6387 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
| 6388 | #endif |
| 6389 | |
Heiko Carstens | b50f60c | 2006-07-30 03:03:52 -0700 | [diff] [blame] | 6390 | #ifdef CONFIG_RT_MUTEXES |
| 6391 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); |
| 6392 | #endif |
| 6393 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6394 | /* |
| 6395 | * The boot idle thread does lazy MMU switching as well: |
| 6396 | */ |
| 6397 | atomic_inc(&init_mm.mm_count); |
| 6398 | enter_lazy_tlb(&init_mm, current); |
| 6399 | |
| 6400 | /* |
| 6401 | * Make us the idle thread. Technically, schedule() should not be |
| 6402 | * called from this thread, however somewhere below it might be, |
| 6403 | * but because we are the idle thread, we just pick up running again |
| 6404 | * when this runqueue becomes "idle". |
| 6405 | */ |
| 6406 | init_idle(current, smp_processor_id()); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6407 | /* |
| 6408 | * During early bootup we pretend to be a normal task: |
| 6409 | */ |
| 6410 | current->sched_class = &fair_sched_class; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6411 | } |
| 6412 | |
| 6413 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
| 6414 | void __might_sleep(char *file, int line) |
| 6415 | { |
Ingo Molnar | 48f24c4 | 2006-07-03 00:25:40 -0700 | [diff] [blame] | 6416 | #ifdef in_atomic |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6417 | static unsigned long prev_jiffy; /* ratelimiting */ |
| 6418 | |
| 6419 | if ((in_atomic() || irqs_disabled()) && |
| 6420 | system_state == SYSTEM_RUNNING && !oops_in_progress) { |
| 6421 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
| 6422 | return; |
| 6423 | prev_jiffy = jiffies; |
Ingo Molnar | 91368d7 | 2006-03-23 03:00:54 -0800 | [diff] [blame] | 6424 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6425 | " context at %s:%d\n", file, line); |
| 6426 | printk("in_atomic():%d, irqs_disabled():%d\n", |
| 6427 | in_atomic(), irqs_disabled()); |
Peter Zijlstra | a4c410f | 2006-12-06 20:37:21 -0800 | [diff] [blame] | 6428 | debug_show_held_locks(current); |
Ingo Molnar | 3117df0 | 2006-12-13 00:34:43 -0800 | [diff] [blame] | 6429 | if (irqs_disabled()) |
| 6430 | print_irqtrace_events(current); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6431 | dump_stack(); |
| 6432 | } |
| 6433 | #endif |
| 6434 | } |
| 6435 | EXPORT_SYMBOL(__might_sleep); |
| 6436 | #endif |
| 6437 | |
| 6438 | #ifdef CONFIG_MAGIC_SYSRQ |
| 6439 | void normalize_rt_tasks(void) |
| 6440 | { |
Ingo Molnar | a0f98a1 | 2007-06-17 18:37:45 +0200 | [diff] [blame] | 6441 | struct task_struct *g, *p; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6442 | unsigned long flags; |
Ingo Molnar | 70b97a7 | 2006-07-03 00:25:42 -0700 | [diff] [blame] | 6443 | struct rq *rq; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6444 | int on_rq; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6445 | |
| 6446 | read_lock_irq(&tasklist_lock); |
Ingo Molnar | a0f98a1 | 2007-06-17 18:37:45 +0200 | [diff] [blame] | 6447 | do_each_thread(g, p) { |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6448 | p->se.fair_key = 0; |
| 6449 | p->se.wait_runtime = 0; |
| 6450 | p->se.wait_start_fair = 0; |
| 6451 | p->se.wait_start = 0; |
| 6452 | p->se.exec_start = 0; |
| 6453 | p->se.sleep_start = 0; |
| 6454 | p->se.sleep_start_fair = 0; |
| 6455 | p->se.block_start = 0; |
| 6456 | task_rq(p)->cfs.fair_clock = 0; |
| 6457 | task_rq(p)->clock = 0; |
| 6458 | |
| 6459 | if (!rt_task(p)) { |
| 6460 | /* |
| 6461 | * Renice negative nice level userspace |
| 6462 | * tasks back to 0: |
| 6463 | */ |
| 6464 | if (TASK_NICE(p) < 0 && p->mm) |
| 6465 | set_user_nice(p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6466 | continue; |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6467 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6468 | |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 6469 | spin_lock_irqsave(&p->pi_lock, flags); |
| 6470 | rq = __task_rq_lock(p); |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6471 | #ifdef CONFIG_SMP |
| 6472 | /* |
| 6473 | * Do not touch the migration thread: |
| 6474 | */ |
| 6475 | if (p == rq->migration_thread) |
| 6476 | goto out_unlock; |
| 6477 | #endif |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6478 | |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6479 | on_rq = p->se.on_rq; |
| 6480 | if (on_rq) |
| 6481 | deactivate_task(task_rq(p), p, 0); |
| 6482 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
| 6483 | if (on_rq) { |
| 6484 | activate_task(task_rq(p), p, 0); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6485 | resched_task(rq->curr); |
| 6486 | } |
Ingo Molnar | dd41f59 | 2007-07-09 18:51:59 +0200 | [diff] [blame] | 6487 | #ifdef CONFIG_SMP |
| 6488 | out_unlock: |
| 6489 | #endif |
Ingo Molnar | b29739f | 2006-06-27 02:54:51 -0700 | [diff] [blame] | 6490 | __task_rq_unlock(rq); |
| 6491 | spin_unlock_irqrestore(&p->pi_lock, flags); |
Ingo Molnar | a0f98a1 | 2007-06-17 18:37:45 +0200 | [diff] [blame] | 6492 | } while_each_thread(g, p); |
| 6493 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 6494 | read_unlock_irq(&tasklist_lock); |
| 6495 | } |
| 6496 | |
| 6497 | #endif /* CONFIG_MAGIC_SYSRQ */ |
Linus Torvalds | 1df5c10 | 2005-09-12 07:59:21 -0700 | [diff] [blame] | 6498 | |
| 6499 | #ifdef CONFIG_IA64 |
| 6500 | /* |
| 6501 | * These functions are only useful for the IA64 MCA handling. |
| 6502 | * |
| 6503 | * They can only be called when the whole system has been |
| 6504 | * stopped - every CPU needs to be quiescent, and no scheduling |
| 6505 | * activity can take place. Using them for anything else would |
| 6506 | * be a serious bug, and as a result, they aren't even visible |
| 6507 | * under any other configuration. |
| 6508 | */ |
| 6509 | |
| 6510 | /** |
| 6511 | * curr_task - return the current task for a given cpu. |
| 6512 | * @cpu: the processor in question. |
| 6513 | * |
| 6514 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
| 6515 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 6516 | struct task_struct *curr_task(int cpu) |
Linus Torvalds | 1df5c10 | 2005-09-12 07:59:21 -0700 | [diff] [blame] | 6517 | { |
| 6518 | return cpu_curr(cpu); |
| 6519 | } |
| 6520 | |
| 6521 | /** |
| 6522 | * set_curr_task - set the current task for a given cpu. |
| 6523 | * @cpu: the processor in question. |
| 6524 | * @p: the task pointer to set. |
| 6525 | * |
| 6526 | * Description: This function must only be used when non-maskable interrupts |
| 6527 | * are serviced on a separate stack. It allows the architecture to switch the |
| 6528 | * notion of the current task on a cpu in a non-blocking manner. This function |
| 6529 | * must be called with all CPU's synchronized, and interrupts disabled, the |
| 6530 | * and caller must save the original value of the current task (see |
| 6531 | * curr_task() above) and restore that value before reenabling interrupts and |
| 6532 | * re-starting the system. |
| 6533 | * |
| 6534 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
| 6535 | */ |
Ingo Molnar | 36c8b58 | 2006-07-03 00:25:41 -0700 | [diff] [blame] | 6536 | void set_curr_task(int cpu, struct task_struct *p) |
Linus Torvalds | 1df5c10 | 2005-09-12 07:59:21 -0700 | [diff] [blame] | 6537 | { |
| 6538 | cpu_curr(cpu) = p; |
| 6539 | } |
| 6540 | |
| 6541 | #endif |