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1da177e4 LT |
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> | |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 LT |
31 | #include <linux/completion.h> |
32 | #include <linux/kernel_stat.h> | |
9a11b49a | 33 | #include <linux/debug_locks.h> |
1da177e4 LT |
34 | #include <linux/security.h> |
35 | #include <linux/notifier.h> | |
36 | #include <linux/profile.h> | |
7dfb7103 | 37 | #include <linux/freezer.h> |
198e2f18 | 38 | #include <linux/vmalloc.h> |
1da177e4 LT |
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> | |
8f0ab514 | 52 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 53 | #include <linux/kprobes.h> |
0ff92245 | 54 | #include <linux/delayacct.h> |
5517d86b | 55 | #include <linux/reciprocal_div.h> |
1da177e4 | 56 | |
5517d86b | 57 | #include <asm/tlb.h> |
1da177e4 LT |
58 | #include <asm/unistd.h> |
59 | ||
b035b6de AD |
60 | /* |
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 | ||
bb29ab26 IM |
70 | /* |
71 | * CPU frequency is/was unstable - start new by setting prev_clock_raw: | |
72 | */ | |
73 | void sched_clock_unstable_event(void) | |
74 | { | |
75 | } | |
76 | ||
1da177e4 LT |
77 | /* |
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 | ||
6aa645ea IM |
101 | #define NICE_0_LOAD SCHED_LOAD_SCALE |
102 | #define NICE_0_SHIFT SCHED_LOAD_SHIFT | |
103 | ||
1da177e4 LT |
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) \ | |
013d3868 MA |
171 | (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \ |
172 | INTERACTIVE_DELTA) | |
1da177e4 LT |
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) \ | |
d5f9f942 | 182 | ((p)->prio < (rq)->curr->prio) |
1da177e4 | 183 | |
1da177e4 | 184 | #define SCALE_PRIO(x, prio) \ |
2dd73a4f | 185 | max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO / 2), MIN_TIMESLICE) |
1da177e4 | 186 | |
2dd73a4f | 187 | static unsigned int static_prio_timeslice(int static_prio) |
1da177e4 | 188 | { |
2dd73a4f PW |
189 | if (static_prio < NICE_TO_PRIO(0)) |
190 | return SCALE_PRIO(DEF_TIMESLICE * 4, static_prio); | |
1da177e4 | 191 | else |
2dd73a4f | 192 | return SCALE_PRIO(DEF_TIMESLICE, static_prio); |
1da177e4 | 193 | } |
2dd73a4f | 194 | |
5517d86b ED |
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 | ||
91fcdd4e BP |
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 | ||
36c8b586 | 225 | static inline unsigned int task_timeslice(struct task_struct *p) |
2dd73a4f PW |
226 | { |
227 | return static_prio_timeslice(p->static_prio); | |
228 | } | |
229 | ||
e05606d3 IM |
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 | ||
1da177e4 | 242 | /* |
6aa645ea | 243 | * This is the priority-queue data structure of the RT scheduling class: |
1da177e4 | 244 | */ |
6aa645ea IM |
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 | }; | |
249 | ||
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 | }; | |
1da177e4 | 287 | |
6aa645ea IM |
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 | */ | |
1da177e4 LT |
298 | struct prio_array { |
299 | unsigned int nr_active; | |
d444886e | 300 | DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */ |
1da177e4 LT |
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 | */ | |
70b97a7f | 311 | struct rq { |
6aa645ea | 312 | spinlock_t lock; /* runqueue lock */ |
1da177e4 LT |
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; | |
2dd73a4f | 319 | unsigned long raw_weighted_load; |
6aa645ea IM |
320 | #define CPU_LOAD_IDX_MAX 5 |
321 | unsigned long cpu_load[CPU_LOAD_IDX_MAX]; | |
bdecea3a | 322 | unsigned char idle_at_tick; |
46cb4b7c SS |
323 | #ifdef CONFIG_NO_HZ |
324 | unsigned char in_nohz_recently; | |
325 | #endif | |
6aa645ea IM |
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 */ | |
1da177e4 | 333 | #endif |
6aa645ea | 334 | struct rt_rq rt; |
1da177e4 LT |
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; | |
b18ec803 | 345 | unsigned long long most_recent_timestamp; |
6aa645ea | 346 | |
36c8b586 | 347 | struct task_struct *curr, *idle; |
c9819f45 | 348 | unsigned long next_balance; |
1da177e4 | 349 | struct mm_struct *prev_mm; |
6aa645ea | 350 | |
70b97a7f | 351 | struct prio_array *active, *expired, arrays[2]; |
1da177e4 | 352 | int best_expired_prio; |
6aa645ea IM |
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 | ||
1da177e4 LT |
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; | |
0a2966b4 | 370 | int cpu; /* cpu of this runqueue */ |
1da177e4 | 371 | |
36c8b586 | 372 | struct task_struct *migration_thread; |
1da177e4 LT |
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 | |
fcb99371 | 395 | struct lock_class_key rq_lock_key; |
1da177e4 LT |
396 | }; |
397 | ||
c3396620 | 398 | static DEFINE_PER_CPU(struct rq, runqueues) ____cacheline_aligned_in_smp; |
5be9361c | 399 | static DEFINE_MUTEX(sched_hotcpu_mutex); |
1da177e4 | 400 | |
dd41f596 IM |
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 | ||
0a2966b4 CL |
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 | ||
20d315d4 IM |
415 | /* |
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 | ||
674311d5 NP |
461 | /* |
462 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 463 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
464 | * |
465 | * The domain tree of any CPU may only be accessed from within | |
466 | * preempt-disabled sections. | |
467 | */ | |
48f24c4d IM |
468 | #define for_each_domain(cpu, __sd) \ |
469 | for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) | |
1da177e4 LT |
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 | ||
138a8aeb IM |
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 | ||
1da177e4 | 488 | #ifndef prepare_arch_switch |
4866cde0 NP |
489 | # define prepare_arch_switch(next) do { } while (0) |
490 | #endif | |
491 | #ifndef finish_arch_switch | |
492 | # define finish_arch_switch(prev) do { } while (0) | |
493 | #endif | |
494 | ||
495 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
70b97a7f | 496 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
497 | { |
498 | return rq->curr == p; | |
499 | } | |
500 | ||
70b97a7f | 501 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
502 | { |
503 | } | |
504 | ||
70b97a7f | 505 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 | 506 | { |
da04c035 IM |
507 | #ifdef CONFIG_DEBUG_SPINLOCK |
508 | /* this is a valid case when another task releases the spinlock */ | |
509 | rq->lock.owner = current; | |
510 | #endif | |
8a25d5de IM |
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 | ||
4866cde0 NP |
518 | spin_unlock_irq(&rq->lock); |
519 | } | |
520 | ||
521 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
70b97a7f | 522 | static inline int task_running(struct rq *rq, struct task_struct *p) |
4866cde0 NP |
523 | { |
524 | #ifdef CONFIG_SMP | |
525 | return p->oncpu; | |
526 | #else | |
527 | return rq->curr == p; | |
528 | #endif | |
529 | } | |
530 | ||
70b97a7f | 531 | static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
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 | ||
70b97a7f | 548 | static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
4866cde0 NP |
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(); | |
1da177e4 | 561 | #endif |
4866cde0 NP |
562 | } |
563 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 | 564 | |
b29739f9 IM |
565 | /* |
566 | * __task_rq_lock - lock the runqueue a given task resides on. | |
567 | * Must be called interrupts disabled. | |
568 | */ | |
70b97a7f | 569 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
570 | __acquires(rq->lock) |
571 | { | |
70b97a7f | 572 | struct rq *rq; |
b29739f9 IM |
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 | ||
1da177e4 LT |
584 | /* |
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 | */ | |
70b97a7f | 589 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
1da177e4 LT |
590 | __acquires(rq->lock) |
591 | { | |
70b97a7f | 592 | struct rq *rq; |
1da177e4 LT |
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 | ||
70b97a7f | 605 | static inline void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
606 | __releases(rq->lock) |
607 | { | |
608 | spin_unlock(&rq->lock); | |
609 | } | |
610 | ||
70b97a7f | 611 | static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
1da177e4 LT |
612 | __releases(rq->lock) |
613 | { | |
614 | spin_unlock_irqrestore(&rq->lock, *flags); | |
615 | } | |
616 | ||
1da177e4 | 617 | /* |
cc2a73b5 | 618 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 619 | */ |
70b97a7f | 620 | static inline struct rq *this_rq_lock(void) |
1da177e4 LT |
621 | __acquires(rq->lock) |
622 | { | |
70b97a7f | 623 | struct rq *rq; |
1da177e4 LT |
624 | |
625 | local_irq_disable(); | |
626 | rq = this_rq(); | |
627 | spin_lock(&rq->lock); | |
628 | ||
629 | return rq; | |
630 | } | |
631 | ||
c24d20db IM |
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 | ||
45bf76df IM |
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 | ||
2dd73a4f PW |
786 | /* |
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 | |
dd41f596 | 801 | #define load_weight(lp) \ |
2dd73a4f PW |
802 | (((lp) * SCHED_LOAD_SCALE) / TIME_SLICE_NICE_ZERO) |
803 | #define PRIO_TO_LOAD_WEIGHT(prio) \ | |
dd41f596 | 804 | load_weight(static_prio_timeslice(prio)) |
2dd73a4f | 805 | #define RTPRIO_TO_LOAD_WEIGHT(rp) \ |
dd41f596 IM |
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 | }; | |
2dd73a4f | 839 | |
36c8b586 | 840 | static inline void |
dd41f596 | 841 | inc_load(struct rq *rq, const struct task_struct *p, u64 now) |
2dd73a4f | 842 | { |
dd41f596 IM |
843 | update_curr_load(rq, now); |
844 | update_load_add(&rq->ls.load, p->se.load.weight); | |
2dd73a4f PW |
845 | } |
846 | ||
36c8b586 | 847 | static inline void |
dd41f596 | 848 | dec_load(struct rq *rq, const struct task_struct *p, u64 now) |
2dd73a4f | 849 | { |
dd41f596 IM |
850 | update_curr_load(rq, now); |
851 | update_load_sub(&rq->ls.load, p->se.load.weight); | |
2dd73a4f PW |
852 | } |
853 | ||
dd41f596 | 854 | static inline void inc_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
2dd73a4f PW |
855 | { |
856 | rq->nr_running++; | |
dd41f596 | 857 | inc_load(rq, p, now); |
2dd73a4f PW |
858 | } |
859 | ||
dd41f596 | 860 | static inline void dec_nr_running(struct task_struct *p, struct rq *rq, u64 now) |
2dd73a4f PW |
861 | { |
862 | rq->nr_running--; | |
dd41f596 | 863 | dec_load(rq, p, now); |
2dd73a4f PW |
864 | } |
865 | ||
dd41f596 IM |
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 | ||
45bf76df IM |
896 | static void set_load_weight(struct task_struct *p) |
897 | { | |
dd41f596 IM |
898 | task_rq(p)->cfs.wait_runtime -= p->se.wait_runtime; |
899 | p->se.wait_runtime = 0; | |
900 | ||
45bf76df | 901 | if (task_has_rt_policy(p)) { |
dd41f596 IM |
902 | p->se.load.weight = prio_to_weight[0] * 2; |
903 | p->se.load.inv_weight = prio_to_wmult[0] >> 1; | |
904 | return; | |
905 | } | |
45bf76df | 906 | |
dd41f596 IM |
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 | } | |
71f8bd46 | 915 | |
dd41f596 IM |
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]; | |
71f8bd46 IM |
918 | } |
919 | ||
dd41f596 IM |
920 | static void |
921 | enqueue_task(struct rq *rq, struct task_struct *p, int wakeup, u64 now) | |
71f8bd46 | 922 | { |
dd41f596 IM |
923 | sched_info_queued(p); |
924 | p->sched_class->enqueue_task(rq, p, wakeup, now); | |
925 | p->se.on_rq = 1; | |
71f8bd46 IM |
926 | } |
927 | ||
dd41f596 IM |
928 | static void |
929 | dequeue_task(struct rq *rq, struct task_struct *p, int sleep, u64 now) | |
71f8bd46 | 930 | { |
dd41f596 IM |
931 | p->sched_class->dequeue_task(rq, p, sleep, now); |
932 | p->se.on_rq = 0; | |
71f8bd46 IM |
933 | } |
934 | ||
14531189 | 935 | /* |
dd41f596 | 936 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 937 | */ |
14531189 IM |
938 | static inline int __normal_prio(struct task_struct *p) |
939 | { | |
dd41f596 | 940 | return p->static_prio; |
14531189 IM |
941 | } |
942 | ||
b29739f9 IM |
943 | /* |
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 | */ | |
36c8b586 | 950 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
951 | { |
952 | int prio; | |
953 | ||
e05606d3 | 954 | if (task_has_rt_policy(p)) |
b29739f9 IM |
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 | */ | |
36c8b586 | 968 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
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 | ||
1da177e4 | 981 | /* |
dd41f596 | 982 | * activate_task - move a task to the runqueue. |
1da177e4 | 983 | */ |
dd41f596 | 984 | static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
1da177e4 | 985 | { |
dd41f596 | 986 | u64 now = rq_clock(rq); |
d425b274 | 987 | |
dd41f596 IM |
988 | if (p->state == TASK_UNINTERRUPTIBLE) |
989 | rq->nr_uninterruptible--; | |
1da177e4 | 990 | |
dd41f596 IM |
991 | enqueue_task(rq, p, wakeup, now); |
992 | inc_nr_running(p, rq, now); | |
1da177e4 LT |
993 | } |
994 | ||
995 | /* | |
dd41f596 | 996 | * activate_idle_task - move idle task to the _front_ of runqueue. |
1da177e4 | 997 | */ |
dd41f596 | 998 | static inline void activate_idle_task(struct task_struct *p, struct rq *rq) |
1da177e4 | 999 | { |
dd41f596 | 1000 | u64 now = rq_clock(rq); |
1da177e4 | 1001 | |
dd41f596 IM |
1002 | if (p->state == TASK_UNINTERRUPTIBLE) |
1003 | rq->nr_uninterruptible--; | |
ece8a684 | 1004 | |
dd41f596 IM |
1005 | enqueue_task(rq, p, 0, now); |
1006 | inc_nr_running(p, rq, now); | |
1da177e4 LT |
1007 | } |
1008 | ||
1009 | /* | |
1010 | * deactivate_task - remove a task from the runqueue. | |
1011 | */ | |
dd41f596 | 1012 | static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
1da177e4 | 1013 | { |
dd41f596 IM |
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); | |
1da177e4 LT |
1021 | } |
1022 | ||
1da177e4 LT |
1023 | /** |
1024 | * task_curr - is this task currently executing on a CPU? | |
1025 | * @p: the task in question. | |
1026 | */ | |
36c8b586 | 1027 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1028 | { |
1029 | return cpu_curr(task_cpu(p)) == p; | |
1030 | } | |
1031 | ||
2dd73a4f PW |
1032 | /* Used instead of source_load when we know the type == 0 */ |
1033 | unsigned long weighted_cpuload(const int cpu) | |
1034 | { | |
dd41f596 IM |
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 | |
2dd73a4f PW |
1044 | } |
1045 | ||
1da177e4 | 1046 | #ifdef CONFIG_SMP |
c65cc870 | 1047 | |
dd41f596 | 1048 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1049 | { |
dd41f596 IM |
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); | |
c65cc870 IM |
1069 | } |
1070 | ||
70b97a7f | 1071 | struct migration_req { |
1da177e4 | 1072 | struct list_head list; |
1da177e4 | 1073 | |
36c8b586 | 1074 | struct task_struct *task; |
1da177e4 LT |
1075 | int dest_cpu; |
1076 | ||
1da177e4 | 1077 | struct completion done; |
70b97a7f | 1078 | }; |
1da177e4 LT |
1079 | |
1080 | /* | |
1081 | * The task's runqueue lock must be held. | |
1082 | * Returns true if you have to wait for migration thread. | |
1083 | */ | |
36c8b586 | 1084 | static int |
70b97a7f | 1085 | migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
1da177e4 | 1086 | { |
70b97a7f | 1087 | struct rq *rq = task_rq(p); |
1da177e4 LT |
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 | */ | |
dd41f596 | 1093 | if (!p->se.on_rq && !task_running(rq, p)) { |
1da177e4 LT |
1094 | set_task_cpu(p, dest_cpu); |
1095 | return 0; | |
1096 | } | |
1097 | ||
1098 | init_completion(&req->done); | |
1da177e4 LT |
1099 | req->task = p; |
1100 | req->dest_cpu = dest_cpu; | |
1101 | list_add(&req->list, &rq->migration_queue); | |
48f24c4d | 1102 | |
1da177e4 LT |
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 | */ | |
36c8b586 | 1115 | void wait_task_inactive(struct task_struct *p) |
1da177e4 LT |
1116 | { |
1117 | unsigned long flags; | |
dd41f596 | 1118 | int running, on_rq; |
70b97a7f | 1119 | struct rq *rq; |
1da177e4 LT |
1120 | |
1121 | repeat: | |
fa490cfd LT |
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)) | |
1142 | cpu_relax(); | |
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 | */ | |
1da177e4 | 1149 | rq = task_rq_lock(p, &flags); |
fa490cfd | 1150 | running = task_running(rq, p); |
dd41f596 | 1151 | on_rq = p->se.on_rq; |
fa490cfd LT |
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)) { | |
1da177e4 | 1161 | cpu_relax(); |
1da177e4 LT |
1162 | goto repeat; |
1163 | } | |
fa490cfd LT |
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 | */ | |
dd41f596 | 1174 | if (unlikely(on_rq)) { |
fa490cfd LT |
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 | */ | |
1da177e4 LT |
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 | */ | |
36c8b586 | 1199 | void kick_process(struct task_struct *p) |
1da177e4 LT |
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 | /* | |
2dd73a4f PW |
1211 | * Return a low guess at the load of a migration-source cpu weighted |
1212 | * according to the scheduling class and "nice" value. | |
1da177e4 LT |
1213 | * |
1214 | * We want to under-estimate the load of migration sources, to | |
1215 | * balance conservatively. | |
1216 | */ | |
a2000572 | 1217 | static inline unsigned long source_load(int cpu, int type) |
1da177e4 | 1218 | { |
70b97a7f | 1219 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1220 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1221 | |
3b0bd9bc | 1222 | if (type == 0) |
dd41f596 | 1223 | return total; |
b910472d | 1224 | |
dd41f596 | 1225 | return min(rq->cpu_load[type-1], total); |
1da177e4 LT |
1226 | } |
1227 | ||
1228 | /* | |
2dd73a4f PW |
1229 | * Return a high guess at the load of a migration-target cpu weighted |
1230 | * according to the scheduling class and "nice" value. | |
1da177e4 | 1231 | */ |
a2000572 | 1232 | static inline unsigned long target_load(int cpu, int type) |
1da177e4 | 1233 | { |
70b97a7f | 1234 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1235 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f | 1236 | |
7897986b | 1237 | if (type == 0) |
dd41f596 | 1238 | return total; |
3b0bd9bc | 1239 | |
dd41f596 | 1240 | return max(rq->cpu_load[type-1], total); |
2dd73a4f PW |
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 | { | |
70b97a7f | 1248 | struct rq *rq = cpu_rq(cpu); |
dd41f596 | 1249 | unsigned long total = weighted_cpuload(cpu); |
2dd73a4f PW |
1250 | unsigned long n = rq->nr_running; |
1251 | ||
dd41f596 | 1252 | return n ? total / n : SCHED_LOAD_SCALE; |
1da177e4 LT |
1253 | } |
1254 | ||
147cbb4b NP |
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 | ||
da5a5522 BD |
1272 | /* Skip over this group if it has no CPUs allowed */ |
1273 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
1274 | goto nextgroup; | |
1275 | ||
147cbb4b | 1276 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
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 */ | |
5517d86b ED |
1292 | avg_load = sg_div_cpu_power(group, |
1293 | avg_load * SCHED_LOAD_SCALE); | |
147cbb4b NP |
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 | } | |
da5a5522 | 1302 | nextgroup: |
147cbb4b NP |
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 | /* | |
0feaece9 | 1312 | * find_idlest_cpu - find the idlest cpu among the cpus in group. |
147cbb4b | 1313 | */ |
95cdf3b7 IM |
1314 | static int |
1315 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1316 | { |
da5a5522 | 1317 | cpumask_t tmp; |
147cbb4b NP |
1318 | unsigned long load, min_load = ULONG_MAX; |
1319 | int idlest = -1; | |
1320 | int i; | |
1321 | ||
da5a5522 BD |
1322 | /* Traverse only the allowed CPUs */ |
1323 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1324 | ||
1325 | for_each_cpu_mask(i, tmp) { | |
2dd73a4f | 1326 | load = weighted_cpuload(i); |
147cbb4b NP |
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 | ||
476d139c NP |
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; | |
147cbb4b | 1352 | |
c96d145e | 1353 | for_each_domain(cpu, tmp) { |
5c45bf27 SS |
1354 | /* |
1355 | * If power savings logic is enabled for a domain, stop there. | |
1356 | */ | |
1357 | if (tmp->flags & SD_POWERSAVINGS_BALANCE) | |
1358 | break; | |
476d139c NP |
1359 | if (tmp->flags & flag) |
1360 | sd = tmp; | |
c96d145e | 1361 | } |
476d139c NP |
1362 | |
1363 | while (sd) { | |
1364 | cpumask_t span; | |
1365 | struct sched_group *group; | |
1a848870 SS |
1366 | int new_cpu, weight; |
1367 | ||
1368 | if (!(sd->flags & flag)) { | |
1369 | sd = sd->child; | |
1370 | continue; | |
1371 | } | |
476d139c NP |
1372 | |
1373 | span = sd->span; | |
1374 | group = find_idlest_group(sd, t, cpu); | |
1a848870 SS |
1375 | if (!group) { |
1376 | sd = sd->child; | |
1377 | continue; | |
1378 | } | |
476d139c | 1379 | |
da5a5522 | 1380 | new_cpu = find_idlest_cpu(group, t, cpu); |
1a848870 SS |
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 | } | |
476d139c | 1386 | |
1a848870 | 1387 | /* Now try balancing at a lower domain level of new_cpu */ |
476d139c | 1388 | cpu = new_cpu; |
476d139c NP |
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 */ | |
1da177e4 LT |
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) | |
36c8b586 | 1414 | static int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
1415 | { |
1416 | cpumask_t tmp; | |
1417 | struct sched_domain *sd; | |
1418 | int i; | |
1419 | ||
4953198b SS |
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) | |
1da177e4 LT |
1430 | return cpu; |
1431 | ||
1432 | for_each_domain(cpu, sd) { | |
1433 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1434 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 LT |
1435 | for_each_cpu_mask(i, tmp) { |
1436 | if (idle_cpu(i)) | |
1437 | return i; | |
1438 | } | |
1439 | } | |
e0f364f4 NP |
1440 | else |
1441 | break; | |
1da177e4 LT |
1442 | } |
1443 | return cpu; | |
1444 | } | |
1445 | #else | |
36c8b586 | 1446 | static inline int wake_idle(int cpu, struct task_struct *p) |
1da177e4 LT |
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 | */ | |
36c8b586 | 1466 | static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
1da177e4 LT |
1467 | { |
1468 | int cpu, this_cpu, success = 0; | |
1469 | unsigned long flags; | |
1470 | long old_state; | |
70b97a7f | 1471 | struct rq *rq; |
1da177e4 | 1472 | #ifdef CONFIG_SMP |
7897986b | 1473 | struct sched_domain *sd, *this_sd = NULL; |
70b97a7f | 1474 | unsigned long load, this_load; |
1da177e4 LT |
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 | ||
dd41f596 | 1483 | if (p->se.on_rq) |
1da177e4 LT |
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 | ||
7897986b NP |
1493 | new_cpu = cpu; |
1494 | ||
1da177e4 LT |
1495 | schedstat_inc(rq, ttwu_cnt); |
1496 | if (cpu == this_cpu) { | |
1497 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
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; | |
1da177e4 LT |
1506 | } |
1507 | } | |
1da177e4 | 1508 | |
7897986b | 1509 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1510 | goto out_set_cpu; |
1511 | ||
1da177e4 | 1512 | /* |
7897986b | 1513 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1514 | */ |
7897986b NP |
1515 | if (this_sd) { |
1516 | int idx = this_sd->wake_idx; | |
1517 | unsigned int imbalance; | |
1da177e4 | 1518 | |
a3f21bce NP |
1519 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1520 | ||
7897986b NP |
1521 | load = source_load(cpu, idx); |
1522 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1523 | |
7897986b NP |
1524 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1525 | ||
a3f21bce NP |
1526 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1527 | unsigned long tl = this_load; | |
33859f7f MOS |
1528 | unsigned long tl_per_task; |
1529 | ||
1530 | tl_per_task = cpu_avg_load_per_task(this_cpu); | |
2dd73a4f | 1531 | |
1da177e4 | 1532 | /* |
a3f21bce NP |
1533 | * If sync wakeup then subtract the (maximum possible) |
1534 | * effect of the currently running task from the load | |
1535 | * of the current CPU: | |
1da177e4 | 1536 | */ |
a3f21bce | 1537 | if (sync) |
dd41f596 | 1538 | tl -= current->se.load.weight; |
a3f21bce NP |
1539 | |
1540 | if ((tl <= load && | |
2dd73a4f | 1541 | tl + target_load(cpu, idx) <= tl_per_task) || |
dd41f596 | 1542 | 100*(tl + p->se.load.weight) <= imbalance*load) { |
a3f21bce NP |
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 | } | |
1da177e4 LT |
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; | |
dd41f596 | 1576 | if (p->se.on_rq) |
1da177e4 LT |
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 */ | |
dd41f596 | 1585 | activate_task(rq, p, 1); |
1da177e4 LT |
1586 | /* |
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 | */ | |
dd41f596 IM |
1594 | if (!sync || cpu != this_cpu) |
1595 | check_preempt_curr(rq, p); | |
1da177e4 LT |
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 | ||
36c8b586 | 1606 | int fastcall wake_up_process(struct task_struct *p) |
1da177e4 LT |
1607 | { |
1608 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1609 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1610 | } | |
1da177e4 LT |
1611 | EXPORT_SYMBOL(wake_up_process); |
1612 | ||
36c8b586 | 1613 | int fastcall wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1614 | { |
1615 | return try_to_wake_up(p, state, 0); | |
1616 | } | |
1617 | ||
1da177e4 LT |
1618 | /* |
1619 | * Perform scheduler related setup for a newly forked process p. | |
1620 | * p is forked by current. | |
dd41f596 IM |
1621 | * |
1622 | * __sched_fork() is basic setup used by init_idle() too: | |
1623 | */ | |
1624 | static void __sched_fork(struct task_struct *p) | |
1625 | { | |
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; | |
476d139c | 1645 | |
dd41f596 IM |
1646 | INIT_LIST_HEAD(&p->run_list); |
1647 | p->se.on_rq = 0; | |
476d139c | 1648 | |
1da177e4 LT |
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; | |
dd41f596 IM |
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); | |
b29739f9 IM |
1671 | |
1672 | /* | |
1673 | * Make sure we do not leak PI boosting priority to the child: | |
1674 | */ | |
1675 | p->prio = current->normal_prio; | |
1676 | ||
52f17b6c | 1677 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1678 | if (likely(sched_info_on())) |
52f17b6c | 1679 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1680 | #endif |
d6077cb8 | 1681 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1682 | p->oncpu = 0; |
1683 | #endif | |
1da177e4 | 1684 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1685 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1686 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1687 | #endif |
476d139c | 1688 | put_cpu(); |
1da177e4 LT |
1689 | } |
1690 | ||
dd41f596 IM |
1691 | /* |
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 | ||
1da177e4 LT |
1697 | /* |
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 | */ | |
36c8b586 | 1704 | void fastcall wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
1da177e4 LT |
1705 | { |
1706 | unsigned long flags; | |
dd41f596 IM |
1707 | struct rq *rq; |
1708 | int this_cpu; | |
1da177e4 LT |
1709 | |
1710 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1711 | BUG_ON(p->state != TASK_RUNNING); |
dd41f596 | 1712 | this_cpu = smp_processor_id(); /* parent's CPU */ |
1da177e4 LT |
1713 | |
1714 | p->prio = effective_prio(p); | |
1715 | ||
dd41f596 IM |
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); | |
1da177e4 | 1719 | } else { |
1da177e4 | 1720 | /* |
dd41f596 IM |
1721 | * Let the scheduling class do new task startup |
1722 | * management (if any): | |
1da177e4 | 1723 | */ |
dd41f596 | 1724 | p->sched_class->task_new(rq, p); |
1da177e4 | 1725 | } |
dd41f596 IM |
1726 | check_preempt_curr(rq, p); |
1727 | task_rq_unlock(rq, &flags); | |
1da177e4 LT |
1728 | } |
1729 | ||
4866cde0 NP |
1730 | /** |
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 | */ | |
70b97a7f | 1742 | static inline void prepare_task_switch(struct rq *rq, struct task_struct *next) |
4866cde0 NP |
1743 | { |
1744 | prepare_lock_switch(rq, next); | |
1745 | prepare_arch_switch(next); | |
1746 | } | |
1747 | ||
1da177e4 LT |
1748 | /** |
1749 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1750 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1751 | * @prev: the thread we just switched away from. |
1752 | * | |
4866cde0 NP |
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. | |
1da177e4 LT |
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 | */ | |
70b97a7f | 1763 | static inline void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1764 | __releases(rq->lock) |
1765 | { | |
1da177e4 | 1766 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1767 | long prev_state; |
1da177e4 LT |
1768 | |
1769 | rq->prev_mm = NULL; | |
1770 | ||
1771 | /* | |
1772 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1773 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1774 | * schedule one last time. The schedule call will never return, and |
1775 | * the scheduled task must drop that reference. | |
c394cc9f | 1776 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
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 | */ | |
55a101f8 | 1782 | prev_state = prev->state; |
4866cde0 NP |
1783 | finish_arch_switch(prev); |
1784 | finish_lock_switch(rq, prev); | |
1da177e4 LT |
1785 | if (mm) |
1786 | mmdrop(mm); | |
c394cc9f | 1787 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 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); | |
1da177e4 | 1793 | put_task_struct(prev); |
c6fd91f0 | 1794 | } |
1da177e4 LT |
1795 | } |
1796 | ||
1797 | /** | |
1798 | * schedule_tail - first thing a freshly forked thread must call. | |
1799 | * @prev: the thread we just switched away from. | |
1800 | */ | |
36c8b586 | 1801 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1802 | __releases(rq->lock) |
1803 | { | |
70b97a7f IM |
1804 | struct rq *rq = this_rq(); |
1805 | ||
4866cde0 NP |
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 | |
1da177e4 LT |
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 | */ | |
dd41f596 | 1819 | static inline void |
70b97a7f | 1820 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1821 | struct task_struct *next) |
1da177e4 | 1822 | { |
dd41f596 | 1823 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1824 | |
dd41f596 IM |
1825 | prepare_task_switch(rq, next); |
1826 | mm = next->mm; | |
1827 | oldmm = prev->active_mm; | |
9226d125 ZA |
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 | ||
dd41f596 | 1835 | if (unlikely(!mm)) { |
1da177e4 LT |
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 | ||
dd41f596 | 1842 | if (unlikely(!prev->mm)) { |
1da177e4 | 1843 | prev->active_mm = NULL; |
1da177e4 LT |
1844 | rq->prev_mm = oldmm; |
1845 | } | |
3a5f5e48 IM |
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 | |
8a25d5de | 1853 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 1854 | #endif |
1da177e4 LT |
1855 | |
1856 | /* Here we just switch the register state and the stack. */ | |
1857 | switch_to(prev, next, prev); | |
1858 | ||
dd41f596 IM |
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); | |
1da177e4 LT |
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 | ||
0a945022 | 1889 | for_each_possible_cpu(i) |
1da177e4 LT |
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 | { | |
cc94abfc SR |
1904 | int i; |
1905 | unsigned long long sum = 0; | |
1da177e4 | 1906 | |
0a945022 | 1907 | for_each_possible_cpu(i) |
1da177e4 LT |
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 | ||
0a945022 | 1917 | for_each_possible_cpu(i) |
1da177e4 LT |
1918 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1919 | ||
1920 | return sum; | |
1921 | } | |
1922 | ||
db1b1fef JS |
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 | ||
48f24c4d | 1938 | /* |
dd41f596 IM |
1939 | * Update rq->cpu_load[] statistics. This function is usually called every |
1940 | * scheduler tick (TICK_NSEC). | |
48f24c4d | 1941 | */ |
dd41f596 | 1942 | static void update_cpu_load(struct rq *this_rq) |
48f24c4d | 1943 | { |
dd41f596 IM |
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 | } | |
48f24c4d IM |
1993 | } |
1994 | ||
dd41f596 IM |
1995 | #ifdef CONFIG_SMP |
1996 | ||
1da177e4 LT |
1997 | /* |
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 | */ | |
70b97a7f | 2003 | static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
2004 | __acquires(rq1->lock) |
2005 | __acquires(rq2->lock) | |
2006 | { | |
054b9108 | 2007 | BUG_ON(!irqs_disabled()); |
1da177e4 LT |
2008 | if (rq1 == rq2) { |
2009 | spin_lock(&rq1->lock); | |
2010 | __acquire(rq2->lock); /* Fake it out ;) */ | |
2011 | } else { | |
c96d145e | 2012 | if (rq1 < rq2) { |
1da177e4 LT |
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 | */ | |
70b97a7f | 2028 | static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
1da177e4 LT |
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 | */ | |
70b97a7f | 2042 | static void double_lock_balance(struct rq *this_rq, struct rq *busiest) |
1da177e4 LT |
2043 | __releases(this_rq->lock) |
2044 | __acquires(busiest->lock) | |
2045 | __acquires(this_rq->lock) | |
2046 | { | |
054b9108 KK |
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 | } | |
1da177e4 | 2052 | if (unlikely(!spin_trylock(&busiest->lock))) { |
c96d145e | 2053 | if (busiest < this_rq) { |
1da177e4 LT |
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 | ||
1da177e4 LT |
2062 | /* |
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 | */ | |
36c8b586 | 2068 | static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
1da177e4 | 2069 | { |
70b97a7f | 2070 | struct migration_req req; |
1da177e4 | 2071 | unsigned long flags; |
70b97a7f | 2072 | struct rq *rq; |
1da177e4 LT |
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; | |
36c8b586 | 2083 | |
1da177e4 LT |
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); | |
36c8b586 | 2089 | |
1da177e4 LT |
2090 | return; |
2091 | } | |
2092 | out: | |
2093 | task_rq_unlock(rq, &flags); | |
2094 | } | |
2095 | ||
2096 | /* | |
476d139c NP |
2097 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2098 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
2099 | */ |
2100 | void sched_exec(void) | |
2101 | { | |
1da177e4 | 2102 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 2103 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 2104 | put_cpu(); |
476d139c NP |
2105 | if (new_cpu != this_cpu) |
2106 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
2107 | } |
2108 | ||
2109 | /* | |
2110 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
2111 | * Both runqueues must be locked. | |
2112 | */ | |
dd41f596 IM |
2113 | static void pull_task(struct rq *src_rq, struct task_struct *p, |
2114 | struct rq *this_rq, int this_cpu) | |
1da177e4 | 2115 | { |
dd41f596 | 2116 | deactivate_task(src_rq, p, 0); |
1da177e4 | 2117 | set_task_cpu(p, this_cpu); |
dd41f596 | 2118 | activate_task(this_rq, p, 0); |
1da177e4 LT |
2119 | /* |
2120 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
2121 | * to be always true for them. | |
2122 | */ | |
dd41f596 | 2123 | check_preempt_curr(this_rq, p); |
1da177e4 LT |
2124 | } |
2125 | ||
2126 | /* | |
2127 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
2128 | */ | |
858119e1 | 2129 | static |
70b97a7f | 2130 | int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
d15bcfdb | 2131 | struct sched_domain *sd, enum cpu_idle_type idle, |
95cdf3b7 | 2132 | int *all_pinned) |
1da177e4 LT |
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 | */ | |
1da177e4 LT |
2140 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
2141 | return 0; | |
81026794 NP |
2142 | *all_pinned = 0; |
2143 | ||
2144 | if (task_running(rq, p)) | |
2145 | return 0; | |
1da177e4 LT |
2146 | |
2147 | /* | |
dd41f596 | 2148 | * Aggressive migration if too many balance attempts have failed: |
1da177e4 | 2149 | */ |
dd41f596 | 2150 | if (sd->nr_balance_failed > sd->cache_nice_tries) |
1da177e4 LT |
2151 | return 1; |
2152 | ||
1da177e4 LT |
2153 | return 1; |
2154 | } | |
2155 | ||
dd41f596 | 2156 | static int balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
2dd73a4f | 2157 | unsigned long max_nr_move, unsigned long max_load_move, |
d15bcfdb | 2158 | struct sched_domain *sd, enum cpu_idle_type idle, |
dd41f596 IM |
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) | |
1da177e4 | 2162 | { |
dd41f596 IM |
2163 | int pulled = 0, pinned = 0, skip_for_load; |
2164 | struct task_struct *p; | |
2165 | long rem_load_move = max_load_move; | |
1da177e4 | 2166 | |
2dd73a4f | 2167 | if (max_nr_move == 0 || max_load_move == 0) |
1da177e4 LT |
2168 | goto out; |
2169 | ||
81026794 NP |
2170 | pinned = 1; |
2171 | ||
1da177e4 | 2172 | /* |
dd41f596 | 2173 | * Start the load-balancing iterator: |
1da177e4 | 2174 | */ |
dd41f596 IM |
2175 | p = iterator->start(iterator->arg); |
2176 | next: | |
2177 | if (!p) | |
1da177e4 | 2178 | goto out; |
50ddd969 PW |
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 | */ | |
dd41f596 IM |
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; | |
615052dc | 2188 | if (skip_for_load || |
dd41f596 | 2189 | !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
48f24c4d | 2190 | |
dd41f596 IM |
2191 | best_prio_seen |= p->prio == best_prio; |
2192 | p = iterator->next(iterator->arg); | |
2193 | goto next; | |
1da177e4 LT |
2194 | } |
2195 | ||
dd41f596 | 2196 | pull_task(busiest, p, this_rq, this_cpu); |
1da177e4 | 2197 | pulled++; |
dd41f596 | 2198 | rem_load_move -= p->se.load.weight; |
1da177e4 | 2199 | |
2dd73a4f PW |
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) { | |
dd41f596 IM |
2205 | if (p->prio < this_best_prio) |
2206 | this_best_prio = p->prio; | |
2207 | p = iterator->next(iterator->arg); | |
2208 | goto next; | |
1da177e4 LT |
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); | |
81026794 NP |
2217 | |
2218 | if (all_pinned) | |
2219 | *all_pinned = pinned; | |
dd41f596 | 2220 | *load_moved = max_load_move - rem_load_move; |
1da177e4 LT |
2221 | return pulled; |
2222 | } | |
2223 | ||
dd41f596 IM |
2224 | /* |
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. | |
2228 | * | |
2229 | * Called with both runqueues locked. | |
2230 | */ | |
2231 | static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, | |
2232 | unsigned long max_nr_move, unsigned long max_load_move, | |
2233 | struct sched_domain *sd, enum cpu_idle_type idle, | |
2234 | int *all_pinned) | |
2235 | { | |
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; | |
2239 | ||
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); | |
2249 | ||
2250 | return total_nr_moved; | |
2251 | } | |
2252 | ||
1da177e4 LT |
2253 | /* |
2254 | * find_busiest_group finds and returns the busiest CPU group within the | |
48f24c4d IM |
2255 | * domain. It calculates and returns the amount of weighted load which |
2256 | * should be moved to restore balance via the imbalance parameter. | |
1da177e4 LT |
2257 | */ |
2258 | static struct sched_group * | |
2259 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
dd41f596 IM |
2260 | unsigned long *imbalance, enum cpu_idle_type idle, |
2261 | int *sd_idle, cpumask_t *cpus, int *balance) | |
1da177e4 LT |
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; | |
0c117f1b | 2265 | unsigned long max_pull; |
2dd73a4f PW |
2266 | unsigned long busiest_load_per_task, busiest_nr_running; |
2267 | unsigned long this_load_per_task, this_nr_running; | |
7897986b | 2268 | int load_idx; |
5c45bf27 SS |
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 | |
1da177e4 LT |
2275 | |
2276 | max_load = this_load = total_load = total_pwr = 0; | |
2dd73a4f PW |
2277 | busiest_load_per_task = busiest_nr_running = 0; |
2278 | this_load_per_task = this_nr_running = 0; | |
d15bcfdb | 2279 | if (idle == CPU_NOT_IDLE) |
7897986b | 2280 | load_idx = sd->busy_idx; |
d15bcfdb | 2281 | else if (idle == CPU_NEWLY_IDLE) |
7897986b NP |
2282 | load_idx = sd->newidle_idx; |
2283 | else | |
2284 | load_idx = sd->idle_idx; | |
1da177e4 LT |
2285 | |
2286 | do { | |
5c45bf27 | 2287 | unsigned long load, group_capacity; |
1da177e4 LT |
2288 | int local_group; |
2289 | int i; | |
783609c6 | 2290 | unsigned int balance_cpu = -1, first_idle_cpu = 0; |
2dd73a4f | 2291 | unsigned long sum_nr_running, sum_weighted_load; |
1da177e4 LT |
2292 | |
2293 | local_group = cpu_isset(this_cpu, group->cpumask); | |
2294 | ||
783609c6 SS |
2295 | if (local_group) |
2296 | balance_cpu = first_cpu(group->cpumask); | |
2297 | ||
1da177e4 | 2298 | /* Tally up the load of all CPUs in the group */ |
2dd73a4f | 2299 | sum_weighted_load = sum_nr_running = avg_load = 0; |
1da177e4 LT |
2300 | |
2301 | for_each_cpu_mask(i, group->cpumask) { | |
0a2966b4 CL |
2302 | struct rq *rq; |
2303 | ||
2304 | if (!cpu_isset(i, *cpus)) | |
2305 | continue; | |
2306 | ||
2307 | rq = cpu_rq(i); | |
2dd73a4f | 2308 | |
5969fe06 NP |
2309 | if (*sd_idle && !idle_cpu(i)) |
2310 | *sd_idle = 0; | |
2311 | ||
1da177e4 | 2312 | /* Bias balancing toward cpus of our domain */ |
783609c6 SS |
2313 | if (local_group) { |
2314 | if (idle_cpu(i) && !first_idle_cpu) { | |
2315 | first_idle_cpu = 1; | |
2316 | balance_cpu = i; | |
2317 | } | |
2318 | ||
a2000572 | 2319 | load = target_load(i, load_idx); |
783609c6 | 2320 | } else |
a2000572 | 2321 | load = source_load(i, load_idx); |
1da177e4 LT |
2322 | |
2323 | avg_load += load; | |
2dd73a4f | 2324 | sum_nr_running += rq->nr_running; |
dd41f596 | 2325 | sum_weighted_load += weighted_cpuload(i); |
1da177e4 LT |
2326 | } |
2327 | ||
783609c6 SS |
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 | ||
1da177e4 | 2338 | total_load += avg_load; |
5517d86b | 2339 | total_pwr += group->__cpu_power; |
1da177e4 LT |
2340 | |
2341 | /* Adjust by relative CPU power of the group */ | |
5517d86b ED |
2342 | avg_load = sg_div_cpu_power(group, |
2343 | avg_load * SCHED_LOAD_SCALE); | |
1da177e4 | 2344 | |
5517d86b | 2345 | group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
5c45bf27 | 2346 | |
1da177e4 LT |
2347 | if (local_group) { |
2348 | this_load = avg_load; | |
2349 | this = group; | |
2dd73a4f PW |
2350 | this_nr_running = sum_nr_running; |
2351 | this_load_per_task = sum_weighted_load; | |
2352 | } else if (avg_load > max_load && | |
5c45bf27 | 2353 | sum_nr_running > group_capacity) { |
1da177e4 LT |
2354 | max_load = avg_load; |
2355 | busiest = group; | |
2dd73a4f PW |
2356 | busiest_nr_running = sum_nr_running; |
2357 | busiest_load_per_task = sum_weighted_load; | |
1da177e4 | 2358 | } |
5c45bf27 SS |
2359 | |
2360 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) | |
2361 | /* | |
2362 | * Busy processors will not participate in power savings | |
2363 | * balance. | |
2364 | */ | |
dd41f596 IM |
2365 | if (idle == CPU_NOT_IDLE || |
2366 | !(sd->flags & SD_POWERSAVINGS_BALANCE)) | |
2367 | goto group_next; | |
5c45bf27 SS |
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 | ||
dd41f596 | 2377 | /* |
5c45bf27 SS |
2378 | * If a group is already running at full capacity or idle, |
2379 | * don't include that group in power savings calculations | |
dd41f596 IM |
2380 | */ |
2381 | if (!power_savings_balance || sum_nr_running >= group_capacity | |
5c45bf27 | 2382 | || !sum_nr_running) |
dd41f596 | 2383 | goto group_next; |
5c45bf27 | 2384 | |
dd41f596 | 2385 | /* |
5c45bf27 | 2386 | * Calculate the group which has the least non-idle load. |
dd41f596 IM |
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 && | |
5c45bf27 SS |
2392 | first_cpu(group->cpumask) < |
2393 | first_cpu(group_min->cpumask))) { | |
dd41f596 IM |
2394 | group_min = group; |
2395 | min_nr_running = sum_nr_running; | |
5c45bf27 SS |
2396 | min_load_per_task = sum_weighted_load / |
2397 | sum_nr_running; | |
dd41f596 | 2398 | } |
5c45bf27 | 2399 | |
dd41f596 | 2400 | /* |
5c45bf27 | 2401 | * Calculate the group which is almost near its |
dd41f596 IM |
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 | } | |
48f24c4d | 2413 | } |
5c45bf27 SS |
2414 | group_next: |
2415 | #endif | |
1da177e4 LT |
2416 | group = group->next; |
2417 | } while (group != sd->groups); | |
2418 | ||
2dd73a4f | 2419 | if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
1da177e4 LT |
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 | ||
2dd73a4f | 2428 | busiest_load_per_task /= busiest_nr_running; |
1da177e4 LT |
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 | */ | |
2dd73a4f PW |
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 | } | |
0c117f1b SS |
2452 | |
2453 | /* Don't want to pull so many tasks that a group would go idle */ | |
2dd73a4f | 2454 | max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
0c117f1b | 2455 | |
1da177e4 | 2456 | /* How much load to actually move to equalise the imbalance */ |
5517d86b ED |
2457 | *imbalance = min(max_pull * busiest->__cpu_power, |
2458 | (avg_load - this_load) * this->__cpu_power) | |
1da177e4 LT |
2459 | / SCHED_LOAD_SCALE; |
2460 | ||
2dd73a4f PW |
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 | */ | |
dd41f596 | 2467 | if (*imbalance + SCHED_LOAD_SCALE_FUZZ < busiest_load_per_task/2) { |
48f24c4d | 2468 | unsigned long tmp, pwr_now, pwr_move; |
2dd73a4f PW |
2469 | unsigned int imbn; |
2470 | ||
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; | |
1da177e4 | 2480 | |
dd41f596 IM |
2481 | if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >= |
2482 | busiest_load_per_task * imbn) { | |
2dd73a4f | 2483 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
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 | ||
5517d86b ED |
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); | |
1da177e4 LT |
2497 | pwr_now /= SCHED_LOAD_SCALE; |
2498 | ||
2499 | /* Amount of load we'd subtract */ | |
5517d86b ED |
2500 | tmp = sg_div_cpu_power(busiest, |
2501 | busiest_load_per_task * SCHED_LOAD_SCALE); | |
1da177e4 | 2502 | if (max_load > tmp) |
5517d86b | 2503 | pwr_move += busiest->__cpu_power * |
2dd73a4f | 2504 | min(busiest_load_per_task, max_load - tmp); |
1da177e4 LT |
2505 | |
2506 | /* Amount of load we'd add */ | |
5517d86b | 2507 | if (max_load * busiest->__cpu_power < |
33859f7f | 2508 | busiest_load_per_task * SCHED_LOAD_SCALE) |
5517d86b ED |
2509 | tmp = sg_div_cpu_power(this, |
2510 | max_load * busiest->__cpu_power); | |
1da177e4 | 2511 | else |
5517d86b ED |
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); | |
1da177e4 LT |
2516 | pwr_move /= SCHED_LOAD_SCALE; |
2517 | ||
2518 | /* Move if we gain throughput */ | |
2519 | if (pwr_move <= pwr_now) | |
2520 | goto out_balanced; | |
2521 | ||
2dd73a4f | 2522 | *imbalance = busiest_load_per_task; |
1da177e4 LT |
2523 | } |
2524 | ||
1da177e4 LT |
2525 | return busiest; |
2526 | ||
2527 | out_balanced: | |
5c45bf27 | 2528 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
d15bcfdb | 2529 | if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
5c45bf27 | 2530 | goto ret; |
1da177e4 | 2531 | |
5c45bf27 SS |
2532 | if (this == group_leader && group_leader != group_min) { |
2533 | *imbalance = min_load_per_task; | |
2534 | return group_min; | |
2535 | } | |
5c45bf27 | 2536 | #endif |
783609c6 | 2537 | ret: |
1da177e4 LT |
2538 | *imbalance = 0; |
2539 | return NULL; | |
2540 | } | |
2541 | ||
2542 | /* | |
2543 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2544 | */ | |
70b97a7f | 2545 | static struct rq * |
d15bcfdb | 2546 | find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
0a2966b4 | 2547 | unsigned long imbalance, cpumask_t *cpus) |
1da177e4 | 2548 | { |
70b97a7f | 2549 | struct rq *busiest = NULL, *rq; |
2dd73a4f | 2550 | unsigned long max_load = 0; |
1da177e4 LT |
2551 | int i; |
2552 | ||
2553 | for_each_cpu_mask(i, group->cpumask) { | |
dd41f596 | 2554 | unsigned long wl; |
0a2966b4 CL |
2555 | |
2556 | if (!cpu_isset(i, *cpus)) | |
2557 | continue; | |
2558 | ||
48f24c4d | 2559 | rq = cpu_rq(i); |
dd41f596 | 2560 | wl = weighted_cpuload(i); |
2dd73a4f | 2561 | |
dd41f596 | 2562 | if (rq->nr_running == 1 && wl > imbalance) |
2dd73a4f | 2563 | continue; |
1da177e4 | 2564 | |
dd41f596 IM |
2565 | if (wl > max_load) { |
2566 | max_load = wl; | |
48f24c4d | 2567 | busiest = rq; |
1da177e4 LT |
2568 | } |
2569 | } | |
2570 | ||
2571 | return busiest; | |
2572 | } | |
2573 | ||
77391d71 NP |
2574 | /* |
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 | ||
48f24c4d IM |
2580 | static inline unsigned long minus_1_or_zero(unsigned long n) |
2581 | { | |
2582 | return n > 0 ? n - 1 : 0; | |
2583 | } | |
2584 | ||
1da177e4 LT |
2585 | /* |
2586 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2587 | * tasks if there is an imbalance. | |
1da177e4 | 2588 | */ |
70b97a7f | 2589 | static int load_balance(int this_cpu, struct rq *this_rq, |
d15bcfdb | 2590 | struct sched_domain *sd, enum cpu_idle_type idle, |
783609c6 | 2591 | int *balance) |
1da177e4 | 2592 | { |
48f24c4d | 2593 | int nr_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
1da177e4 | 2594 | struct sched_group *group; |
1da177e4 | 2595 | unsigned long imbalance; |
70b97a7f | 2596 | struct rq *busiest; |
0a2966b4 | 2597 | cpumask_t cpus = CPU_MASK_ALL; |
fe2eea3f | 2598 | unsigned long flags; |
5969fe06 | 2599 | |
89c4710e SS |
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, | |
dd41f596 | 2603 | * let the state of idle sibling percolate up as CPU_IDLE, instead of |
d15bcfdb | 2604 | * portraying it as CPU_NOT_IDLE. |
89c4710e | 2605 | */ |
d15bcfdb | 2606 | if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2607 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2608 | sd_idle = 1; |
1da177e4 | 2609 | |
1da177e4 LT |
2610 | schedstat_inc(sd, lb_cnt[idle]); |
2611 | ||
0a2966b4 CL |
2612 | redo: |
2613 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, | |
783609c6 SS |
2614 | &cpus, balance); |
2615 | ||
06066714 | 2616 | if (*balance == 0) |
783609c6 | 2617 | goto out_balanced; |
783609c6 | 2618 | |
1da177e4 LT |
2619 | if (!group) { |
2620 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2621 | goto out_balanced; | |
2622 | } | |
2623 | ||
0a2966b4 | 2624 | busiest = find_busiest_queue(group, idle, imbalance, &cpus); |
1da177e4 LT |
2625 | if (!busiest) { |
2626 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2627 | goto out_balanced; | |
2628 | } | |
2629 | ||
db935dbd | 2630 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
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 | */ | |
fe2eea3f | 2642 | local_irq_save(flags); |
e17224bf | 2643 | double_rq_lock(this_rq, busiest); |
1da177e4 | 2644 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
48f24c4d IM |
2645 | minus_1_or_zero(busiest->nr_running), |
2646 | imbalance, sd, idle, &all_pinned); | |
e17224bf | 2647 | double_rq_unlock(this_rq, busiest); |
fe2eea3f | 2648 | local_irq_restore(flags); |
81026794 | 2649 | |
46cb4b7c SS |
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 | ||
81026794 | 2656 | /* All tasks on this runqueue were pinned by CPU affinity */ |
0a2966b4 CL |
2657 | if (unlikely(all_pinned)) { |
2658 | cpu_clear(cpu_of(busiest), cpus); | |
2659 | if (!cpus_empty(cpus)) | |
2660 | goto redo; | |
81026794 | 2661 | goto out_balanced; |
0a2966b4 | 2662 | } |
1da177e4 | 2663 | } |
81026794 | 2664 | |
1da177e4 LT |
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)) { | |
1da177e4 | 2670 | |
fe2eea3f | 2671 | spin_lock_irqsave(&busiest->lock, flags); |
fa3b6ddc SS |
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)) { | |
fe2eea3f | 2677 | spin_unlock_irqrestore(&busiest->lock, flags); |
fa3b6ddc SS |
2678 | all_pinned = 1; |
2679 | goto out_one_pinned; | |
2680 | } | |
2681 | ||
1da177e4 LT |
2682 | if (!busiest->active_balance) { |
2683 | busiest->active_balance = 1; | |
2684 | busiest->push_cpu = this_cpu; | |
81026794 | 2685 | active_balance = 1; |
1da177e4 | 2686 | } |
fe2eea3f | 2687 | spin_unlock_irqrestore(&busiest->lock, flags); |
81026794 | 2688 | if (active_balance) |
1da177e4 LT |
2689 | wake_up_process(busiest->migration_thread); |
2690 | ||
2691 | /* | |
2692 | * We've kicked active balancing, reset the failure | |
2693 | * counter. | |
2694 | */ | |
39507451 | 2695 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2696 | } |
81026794 | 2697 | } else |
1da177e4 LT |
2698 | sd->nr_balance_failed = 0; |
2699 | ||
81026794 | 2700 | if (likely(!active_balance)) { |
1da177e4 LT |
2701 | /* We were unbalanced, so reset the balancing interval */ |
2702 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
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; | |
1da177e4 LT |
2712 | } |
2713 | ||
5c45bf27 | 2714 | if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2715 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2716 | return -1; |
1da177e4 LT |
2717 | return nr_moved; |
2718 | ||
2719 | out_balanced: | |
1da177e4 LT |
2720 | schedstat_inc(sd, lb_balanced[idle]); |
2721 | ||
16cfb1c0 | 2722 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2723 | |
2724 | out_one_pinned: | |
1da177e4 | 2725 | /* tune up the balancing interval */ |
77391d71 NP |
2726 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2727 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2728 | sd->balance_interval *= 2; |
2729 | ||
48f24c4d | 2730 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2731 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2732 | return -1; |
1da177e4 LT |
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 | * | |
d15bcfdb | 2740 | * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
1da177e4 LT |
2741 | * this_rq is locked. |
2742 | */ | |
48f24c4d | 2743 | static int |
70b97a7f | 2744 | load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd) |
1da177e4 LT |
2745 | { |
2746 | struct sched_group *group; | |
70b97a7f | 2747 | struct rq *busiest = NULL; |
1da177e4 LT |
2748 | unsigned long imbalance; |
2749 | int nr_moved = 0; | |
5969fe06 | 2750 | int sd_idle = 0; |
0a2966b4 | 2751 | cpumask_t cpus = CPU_MASK_ALL; |
5969fe06 | 2752 | |
89c4710e SS |
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 | |
d15bcfdb | 2757 | * portraying it as CPU_NOT_IDLE. |
89c4710e SS |
2758 | */ |
2759 | if (sd->flags & SD_SHARE_CPUPOWER && | |
2760 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 | 2761 | sd_idle = 1; |
1da177e4 | 2762 | |
d15bcfdb | 2763 | schedstat_inc(sd, lb_cnt[CPU_NEWLY_IDLE]); |
0a2966b4 | 2764 | redo: |
d15bcfdb | 2765 | group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
783609c6 | 2766 | &sd_idle, &cpus, NULL); |
1da177e4 | 2767 | if (!group) { |
d15bcfdb | 2768 | schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2769 | goto out_balanced; |
1da177e4 LT |
2770 | } |
2771 | ||
d15bcfdb | 2772 | busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, |
0a2966b4 | 2773 | &cpus); |
db935dbd | 2774 | if (!busiest) { |
d15bcfdb | 2775 | schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
16cfb1c0 | 2776 | goto out_balanced; |
1da177e4 LT |
2777 | } |
2778 | ||
db935dbd NP |
2779 | BUG_ON(busiest == this_rq); |
2780 | ||
d15bcfdb | 2781 | schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
d6d5cfaf NP |
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, | |
2dd73a4f | 2788 | minus_1_or_zero(busiest->nr_running), |
d15bcfdb | 2789 | imbalance, sd, CPU_NEWLY_IDLE, NULL); |
d6d5cfaf | 2790 | spin_unlock(&busiest->lock); |
0a2966b4 CL |
2791 | |
2792 | if (!nr_moved) { | |
2793 | cpu_clear(cpu_of(busiest), cpus); | |
2794 | if (!cpus_empty(cpus)) | |
2795 | goto redo; | |
2796 | } | |
d6d5cfaf NP |
2797 | } |
2798 | ||
5969fe06 | 2799 | if (!nr_moved) { |
d15bcfdb | 2800 | schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
89c4710e SS |
2801 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
2802 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) | |
5969fe06 NP |
2803 | return -1; |
2804 | } else | |
16cfb1c0 | 2805 | sd->nr_balance_failed = 0; |
1da177e4 | 2806 | |
1da177e4 | 2807 | return nr_moved; |
16cfb1c0 NP |
2808 | |
2809 | out_balanced: | |
d15bcfdb | 2810 | schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
48f24c4d | 2811 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
89c4710e | 2812 | !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
5969fe06 | 2813 | return -1; |
16cfb1c0 | 2814 | sd->nr_balance_failed = 0; |
48f24c4d | 2815 | |
16cfb1c0 | 2816 | return 0; |
1da177e4 LT |
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 | */ | |
70b97a7f | 2823 | static void idle_balance(int this_cpu, struct rq *this_rq) |
1da177e4 LT |
2824 | { |
2825 | struct sched_domain *sd; | |
dd41f596 IM |
2826 | int pulled_task = -1; |
2827 | unsigned long next_balance = jiffies + HZ; | |
1da177e4 LT |
2828 | |
2829 | for_each_domain(this_cpu, sd) { | |
92c4ca5c CL |
2830 | unsigned long interval; |
2831 | ||
2832 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2833 | continue; | |
2834 | ||
2835 | if (sd->flags & SD_BALANCE_NEWIDLE) | |
48f24c4d | 2836 | /* If we've pulled tasks over stop searching: */ |
1bd77f2d | 2837 | pulled_task = load_balance_newidle(this_cpu, |
92c4ca5c CL |
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; | |
1da177e4 | 2845 | } |
dd41f596 | 2846 | if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
1bd77f2d CL |
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; | |
dd41f596 | 2852 | } |
1da177e4 LT |
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 | */ | |
70b97a7f | 2863 | static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
1da177e4 | 2864 | { |
39507451 | 2865 | int target_cpu = busiest_rq->push_cpu; |
70b97a7f IM |
2866 | struct sched_domain *sd; |
2867 | struct rq *target_rq; | |
39507451 | 2868 | |
48f24c4d | 2869 | /* Is there any task to move? */ |
39507451 | 2870 | if (busiest_rq->nr_running <= 1) |
39507451 NP |
2871 | return; |
2872 | ||
2873 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2874 | |
2875 | /* | |
39507451 NP |
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. | |
1da177e4 | 2879 | */ |
39507451 | 2880 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2881 | |
39507451 NP |
2882 | /* move a task from busiest_rq to target_rq */ |
2883 | double_lock_balance(busiest_rq, target_rq); | |
2884 | ||
2885 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2886 | for_each_domain(target_cpu, sd) { |
39507451 | 2887 | if ((sd->flags & SD_LOAD_BALANCE) && |
48f24c4d | 2888 | cpu_isset(busiest_cpu, sd->span)) |
39507451 | 2889 | break; |
c96d145e | 2890 | } |
39507451 | 2891 | |
48f24c4d IM |
2892 | if (likely(sd)) { |
2893 | schedstat_inc(sd, alb_cnt); | |
39507451 | 2894 | |
48f24c4d | 2895 | if (move_tasks(target_rq, target_cpu, busiest_rq, 1, |
d15bcfdb | 2896 | RTPRIO_TO_LOAD_WEIGHT(100), sd, CPU_IDLE, |
48f24c4d IM |
2897 | NULL)) |
2898 | schedstat_inc(sd, alb_pushed); | |
2899 | else | |
2900 | schedstat_inc(sd, alb_failed); | |
2901 | } | |
39507451 | 2902 | spin_unlock(&target_rq->lock); |
1da177e4 LT |
2903 | } |
2904 | ||
46cb4b7c SS |
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 | ||
7835b98b | 2914 | /* |
46cb4b7c SS |
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... | |
2921 | * | |
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.. | |
7835b98b | 2925 | * |
46cb4b7c SS |
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 | /* | |
7835b98b CL |
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 | */ | |
d15bcfdb | 2987 | static inline void rebalance_domains(int cpu, enum cpu_idle_type idle) |
7835b98b | 2988 | { |
46cb4b7c SS |
2989 | int balance = 1; |
2990 | struct rq *rq = cpu_rq(cpu); | |
7835b98b CL |
2991 | unsigned long interval; |
2992 | struct sched_domain *sd; | |
46cb4b7c | 2993 | /* Earliest time when we have to do rebalance again */ |
c9819f45 | 2994 | unsigned long next_balance = jiffies + 60*HZ; |
1da177e4 | 2995 | |
46cb4b7c | 2996 | for_each_domain(cpu, sd) { |
1da177e4 LT |
2997 | if (!(sd->flags & SD_LOAD_BALANCE)) |
2998 | continue; | |
2999 | ||
3000 | interval = sd->balance_interval; | |
d15bcfdb | 3001 | if (idle != CPU_IDLE) |
1da177e4 LT |
3002 | interval *= sd->busy_factor; |
3003 | ||
3004 | /* scale ms to jiffies */ | |
3005 | interval = msecs_to_jiffies(interval); | |
3006 | if (unlikely(!interval)) | |
3007 | interval = 1; | |
dd41f596 IM |
3008 | if (interval > HZ*NR_CPUS/10) |
3009 | interval = HZ*NR_CPUS/10; | |
3010 | ||
1da177e4 | 3011 | |
08c183f3 CL |
3012 | if (sd->flags & SD_SERIALIZE) { |
3013 | if (!spin_trylock(&balancing)) | |
3014 | goto out; | |
3015 | } | |
3016 | ||
c9819f45 | 3017 | if (time_after_eq(jiffies, sd->last_balance + interval)) { |
46cb4b7c | 3018 | if (load_balance(cpu, rq, sd, idle, &balance)) { |
fa3b6ddc SS |
3019 | /* |
3020 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
3021 | * longer idle, or one of our SMT siblings is |
3022 | * not idle. | |
3023 | */ | |
d15bcfdb | 3024 | idle = CPU_NOT_IDLE; |
1da177e4 | 3025 | } |
1bd77f2d | 3026 | sd->last_balance = jiffies; |
1da177e4 | 3027 | } |
08c183f3 CL |
3028 | if (sd->flags & SD_SERIALIZE) |
3029 | spin_unlock(&balancing); | |
3030 | out: | |
c9819f45 CL |
3031 | if (time_after(next_balance, sd->last_balance + interval)) |
3032 | next_balance = sd->last_balance + interval; | |
783609c6 SS |
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; | |
1da177e4 | 3041 | } |
46cb4b7c SS |
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 | { | |
dd41f596 IM |
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; | |
46cb4b7c | 3056 | |
dd41f596 | 3057 | rebalance_domains(this_cpu, idle); |
46cb4b7c SS |
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 | */ | |
dd41f596 IM |
3065 | if (this_rq->idle_at_tick && |
3066 | atomic_read(&nohz.load_balancer) == this_cpu) { | |
46cb4b7c SS |
3067 | cpumask_t cpus = nohz.cpu_mask; |
3068 | struct rq *rq; | |
3069 | int balance_cpu; | |
3070 | ||
dd41f596 | 3071 | cpu_clear(this_cpu, cpus); |
46cb4b7c SS |
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 | ||
dd41f596 | 3081 | rebalance_domains(balance_cpu, SCHED_IDLE); |
46cb4b7c SS |
3082 | |
3083 | rq = cpu_rq(balance_cpu); | |
dd41f596 IM |
3084 | if (time_after(this_rq->next_balance, rq->next_balance)) |
3085 | this_rq->next_balance = rq->next_balance; | |
46cb4b7c SS |
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 | */ | |
dd41f596 | 3098 | static inline void trigger_load_balance(struct rq *rq, int cpu) |
46cb4b7c | 3099 | { |
46cb4b7c SS |
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); | |
1da177e4 | 3150 | } |
dd41f596 IM |
3151 | |
3152 | #else /* CONFIG_SMP */ | |
3153 | ||
1da177e4 LT |
3154 | /* |
3155 | * on UP we do not need to balance between CPUs: | |
3156 | */ | |
70b97a7f | 3157 | static inline void idle_balance(int cpu, struct rq *rq) |
1da177e4 LT |
3158 | { |
3159 | } | |
dd41f596 IM |
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 | ||
1da177e4 LT |
3174 | #endif |
3175 | ||
1da177e4 LT |
3176 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3177 | ||
3178 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3179 | ||
3180 | /* | |
41b86e9c IM |
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. | |
1da177e4 | 3183 | */ |
41b86e9c | 3184 | unsigned long long task_sched_runtime(struct task_struct *p) |
1da177e4 | 3185 | { |
1da177e4 | 3186 | unsigned long flags; |
41b86e9c IM |
3187 | u64 ns, delta_exec; |
3188 | struct rq *rq; | |
48f24c4d | 3189 | |
41b86e9c IM |
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); | |
48f24c4d | 3198 | |
1da177e4 LT |
3199 | return ns; |
3200 | } | |
3201 | ||
1da177e4 LT |
3202 | /* |
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; | |
70b97a7f | 3233 | struct rq *rq = this_rq(); |
1da177e4 LT |
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); | |
1da177e4 LT |
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); | |
70b97a7f | 3263 | struct rq *rq = this_rq(); |
1da177e4 LT |
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 | ||
7835b98b CL |
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 | { | |
7835b98b CL |
3284 | int cpu = smp_processor_id(); |
3285 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 IM |
3286 | struct task_struct *curr = rq->curr; |
3287 | ||
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); | |
7835b98b | 3293 | |
e418e1c2 | 3294 | #ifdef CONFIG_SMP |
dd41f596 IM |
3295 | rq->idle_at_tick = idle_cpu(cpu); |
3296 | trigger_load_balance(rq, cpu); | |
e418e1c2 | 3297 | #endif |
1da177e4 LT |
3298 | } |
3299 | ||
1da177e4 LT |
3300 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
3301 | ||
3302 | void fastcall add_preempt_count(int val) | |
3303 | { | |
3304 | /* | |
3305 | * Underflow? | |
3306 | */ | |
9a11b49a IM |
3307 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3308 | return; | |
1da177e4 LT |
3309 | preempt_count() += val; |
3310 | /* | |
3311 | * Spinlock count overflowing soon? | |
3312 | */ | |
33859f7f MOS |
3313 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3314 | PREEMPT_MASK - 10); | |
1da177e4 LT |
3315 | } |
3316 | EXPORT_SYMBOL(add_preempt_count); | |
3317 | ||
3318 | void fastcall sub_preempt_count(int val) | |
3319 | { | |
3320 | /* | |
3321 | * Underflow? | |
3322 | */ | |
9a11b49a IM |
3323 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
3324 | return; | |
1da177e4 LT |
3325 | /* |
3326 | * Is the spinlock portion underflowing? | |
3327 | */ | |
9a11b49a IM |
3328 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3329 | !(preempt_count() & PREEMPT_MASK))) | |
3330 | return; | |
3331 | ||
1da177e4 LT |
3332 | preempt_count() -= val; |
3333 | } | |
3334 | EXPORT_SYMBOL(sub_preempt_count); | |
3335 | ||
3336 | #endif | |
3337 | ||
3338 | /* | |
dd41f596 | 3339 | * Print scheduling while atomic bug: |
1da177e4 | 3340 | */ |
dd41f596 | 3341 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3342 | { |
dd41f596 IM |
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 | } | |
1da177e4 | 3350 | |
dd41f596 IM |
3351 | /* |
3352 | * Various schedule()-time debugging checks and statistics: | |
3353 | */ | |
3354 | static inline void schedule_debug(struct task_struct *prev) | |
3355 | { | |
1da177e4 LT |
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 | */ | |
dd41f596 IM |
3361 | if (unlikely(in_atomic_preempt_off()) && unlikely(!prev->exit_state)) |
3362 | __schedule_bug(prev); | |
3363 | ||
1da177e4 LT |
3364 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3365 | ||
dd41f596 IM |
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; | |
1da177e4 LT |
3377 | |
3378 | /* | |
dd41f596 IM |
3379 | * Optimization: we know that if all tasks are in |
3380 | * the fair class we can call that function directly: | |
1da177e4 | 3381 | */ |
dd41f596 IM |
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; | |
1da177e4 LT |
3386 | } |
3387 | ||
dd41f596 IM |
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 | } | |
1da177e4 | 3400 | |
dd41f596 IM |
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 | ||
3412 | need_resched: | |
3413 | preempt_disable(); | |
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 | ||
3420 | release_kernel_lock(prev); | |
3421 | need_resched_nonpreemptible: | |
3422 | ||
3423 | schedule_debug(prev); | |
1da177e4 LT |
3424 | |
3425 | spin_lock_irq(&rq->lock); | |
dd41f596 | 3426 | clear_tsk_need_resched(prev); |
1da177e4 | 3427 | |
1da177e4 | 3428 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
1da177e4 | 3429 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
dd41f596 | 3430 | unlikely(signal_pending(prev)))) { |
1da177e4 | 3431 | prev->state = TASK_RUNNING; |
dd41f596 IM |
3432 | } else { |
3433 | deactivate_task(rq, prev, 1); | |
1da177e4 | 3434 | } |
dd41f596 | 3435 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3436 | } |
3437 | ||
dd41f596 | 3438 | if (unlikely(!rq->nr_running)) |
1da177e4 | 3439 | idle_balance(cpu, rq); |
1da177e4 | 3440 | |
dd41f596 IM |
3441 | now = __rq_clock(rq); |
3442 | prev->sched_class->put_prev_task(rq, prev, now); | |
3443 | next = pick_next_task(rq, prev, now); | |
1da177e4 LT |
3444 | |
3445 | sched_info_switch(prev, next); | |
dd41f596 | 3446 | |
1da177e4 | 3447 | if (likely(prev != next)) { |
1da177e4 LT |
3448 | rq->nr_switches++; |
3449 | rq->curr = next; | |
3450 | ++*switch_count; | |
3451 | ||
dd41f596 | 3452 | context_switch(rq, prev, next); /* unlocks the rq */ |
1da177e4 LT |
3453 | } else |
3454 | spin_unlock_irq(&rq->lock); | |
3455 | ||
dd41f596 IM |
3456 | if (unlikely(reacquire_kernel_lock(current) < 0)) { |
3457 | cpu = smp_processor_id(); | |
3458 | rq = cpu_rq(cpu); | |
1da177e4 | 3459 | goto need_resched_nonpreemptible; |
dd41f596 | 3460 | } |
1da177e4 LT |
3461 | preempt_enable_no_resched(); |
3462 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3463 | goto need_resched; | |
3464 | } | |
1da177e4 LT |
3465 | EXPORT_SYMBOL(schedule); |
3466 | ||
3467 | #ifdef CONFIG_PREEMPT | |
3468 | /* | |
2ed6e34f | 3469 | * this is the entry point to schedule() from in-kernel preemption |
1da177e4 LT |
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 | */ | |
beed33a8 | 3484 | if (likely(ti->preempt_count || irqs_disabled())) |
1da177e4 LT |
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 | } | |
1da177e4 LT |
3509 | EXPORT_SYMBOL(preempt_schedule); |
3510 | ||
3511 | /* | |
2ed6e34f | 3512 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
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 | |
2ed6e34f | 3524 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
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 | ||
95cdf3b7 IM |
3554 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3555 | void *key) | |
1da177e4 | 3556 | { |
48f24c4d | 3557 | return try_to_wake_up(curr->private, mode, sync); |
1da177e4 | 3558 | } |
1da177e4 LT |
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) { | |
48f24c4d IM |
3576 | wait_queue_t *curr = list_entry(tmp, wait_queue_t, task_list); |
3577 | unsigned flags = curr->flags; | |
3578 | ||
1da177e4 | 3579 | if (curr->func(curr, mode, sync, key) && |
48f24c4d | 3580 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
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 | |
67be2dd1 | 3590 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3591 | */ |
3592 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3593 | int nr_exclusive, void *key) |
1da177e4 LT |
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 | } | |
1da177e4 LT |
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 | /** | |
67be2dd1 | 3612 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
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 | */ | |
95cdf3b7 IM |
3624 | void fastcall |
3625 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
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(); | |
48f24c4d | 3669 | |
1da177e4 LT |
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 | } | |
1da177e4 LT |
3814 | EXPORT_SYMBOL(interruptible_sleep_on); |
3815 | ||
95cdf3b7 IM |
3816 | long fastcall __sched |
3817 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) | |
1da177e4 LT |
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 | } | |
1da177e4 LT |
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 | } | |
1da177e4 LT |
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 | ||
b29739f9 IM |
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 | */ | |
36c8b586 | 3870 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 IM |
3871 | { |
3872 | unsigned long flags; | |
dd41f596 | 3873 | int oldprio, on_rq; |
70b97a7f | 3874 | struct rq *rq; |
dd41f596 | 3875 | u64 now; |
b29739f9 IM |
3876 | |
3877 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3878 | ||
3879 | rq = task_rq_lock(p, &flags); | |
dd41f596 | 3880 | now = rq_clock(rq); |
b29739f9 | 3881 | |
d5f9f942 | 3882 | oldprio = p->prio; |
dd41f596 IM |
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 | ||
b29739f9 IM |
3892 | p->prio = prio; |
3893 | ||
dd41f596 IM |
3894 | if (on_rq) { |
3895 | enqueue_task(rq, p, 0, now); | |
b29739f9 IM |
3896 | /* |
3897 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
3898 | * our priority decreased, or if we are not currently running on |
3899 | * this runqueue and our priority is higher than the current's | |
b29739f9 | 3900 | */ |
d5f9f942 AM |
3901 | if (task_running(rq, p)) { |
3902 | if (p->prio > oldprio) | |
3903 | resched_task(rq->curr); | |
dd41f596 IM |
3904 | } else { |
3905 | check_preempt_curr(rq, p); | |
3906 | } | |
b29739f9 IM |
3907 | } |
3908 | task_rq_unlock(rq, &flags); | |
3909 | } | |
3910 | ||
3911 | #endif | |
3912 | ||
36c8b586 | 3913 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3914 | { |
dd41f596 | 3915 | int old_prio, delta, on_rq; |
1da177e4 | 3916 | unsigned long flags; |
70b97a7f | 3917 | struct rq *rq; |
dd41f596 | 3918 | u64 now; |
1da177e4 LT |
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); | |
dd41f596 | 3927 | now = rq_clock(rq); |
1da177e4 LT |
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 | |
dd41f596 | 3932 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 3933 | */ |
e05606d3 | 3934 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
3935 | p->static_prio = NICE_TO_PRIO(nice); |
3936 | goto out_unlock; | |
3937 | } | |
dd41f596 IM |
3938 | on_rq = p->se.on_rq; |
3939 | if (on_rq) { | |
3940 | dequeue_task(rq, p, 0, now); | |
3941 | dec_load(rq, p, now); | |
2dd73a4f | 3942 | } |
1da177e4 | 3943 | |
1da177e4 | 3944 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3945 | set_load_weight(p); |
b29739f9 IM |
3946 | old_prio = p->prio; |
3947 | p->prio = effective_prio(p); | |
3948 | delta = p->prio - old_prio; | |
1da177e4 | 3949 | |
dd41f596 IM |
3950 | if (on_rq) { |
3951 | enqueue_task(rq, p, 0, now); | |
3952 | inc_load(rq, p, now); | |
1da177e4 | 3953 | /* |
d5f9f942 AM |
3954 | * If the task increased its priority or is running and |
3955 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3956 | */ |
d5f9f942 | 3957 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
3958 | resched_task(rq->curr); |
3959 | } | |
3960 | out_unlock: | |
3961 | task_rq_unlock(rq, &flags); | |
3962 | } | |
1da177e4 LT |
3963 | EXPORT_SYMBOL(set_user_nice); |
3964 | ||
e43379f1 MM |
3965 | /* |
3966 | * can_nice - check if a task can reduce its nice value | |
3967 | * @p: task | |
3968 | * @nice: nice value | |
3969 | */ | |
36c8b586 | 3970 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3971 | { |
024f4747 MM |
3972 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
3973 | int nice_rlim = 20 - nice; | |
48f24c4d | 3974 | |
e43379f1 MM |
3975 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
3976 | capable(CAP_SYS_NICE)); | |
3977 | } | |
3978 | ||
1da177e4 LT |
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 | { | |
48f24c4d | 3990 | long nice, retval; |
1da177e4 LT |
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 | */ | |
e43379f1 MM |
3997 | if (increment < -40) |
3998 | increment = -40; | |
1da177e4 LT |
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 | ||
e43379f1 MM |
4008 | if (increment < 0 && !can_nice(current, nice)) |
4009 | return -EPERM; | |
4010 | ||
1da177e4 LT |
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 | */ | |
36c8b586 | 4029 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
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 | */ | |
36c8b586 | 4038 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
4039 | { |
4040 | return TASK_NICE(p); | |
4041 | } | |
1da177e4 | 4042 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
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 | ||
1da177e4 LT |
4053 | /** |
4054 | * idle_task - return the idle task for a given cpu. | |
4055 | * @cpu: the processor in question. | |
4056 | */ | |
36c8b586 | 4057 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
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 | */ | |
36c8b586 | 4066 | static inline struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 LT |
4067 | { |
4068 | return pid ? find_task_by_pid(pid) : current; | |
4069 | } | |
4070 | ||
4071 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
4072 | static void |
4073 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 4074 | { |
dd41f596 | 4075 | BUG_ON(p->se.on_rq); |
48f24c4d | 4076 | |
1da177e4 | 4077 | p->policy = policy; |
dd41f596 IM |
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 | ||
1da177e4 | 4090 | p->rt_priority = prio; |
b29739f9 IM |
4091 | p->normal_prio = normal_prio(p); |
4092 | /* we are holding p->pi_lock already */ | |
4093 | p->prio = rt_mutex_getprio(p); | |
2dd73a4f | 4094 | set_load_weight(p); |
1da177e4 LT |
4095 | } |
4096 | ||
4097 | /** | |
72fd4a35 | 4098 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
1da177e4 LT |
4099 | * @p: the task in question. |
4100 | * @policy: new policy. | |
4101 | * @param: structure containing the new RT priority. | |
5fe1d75f | 4102 | * |
72fd4a35 | 4103 | * NOTE that the task may be already dead. |
1da177e4 | 4104 | */ |
95cdf3b7 IM |
4105 | int sched_setscheduler(struct task_struct *p, int policy, |
4106 | struct sched_param *param) | |
1da177e4 | 4107 | { |
dd41f596 | 4108 | int retval, oldprio, oldpolicy = -1, on_rq; |
1da177e4 | 4109 | unsigned long flags; |
70b97a7f | 4110 | struct rq *rq; |
1da177e4 | 4111 | |
66e5393a SR |
4112 | /* may grab non-irq protected spin_locks */ |
4113 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
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 && | |
dd41f596 IM |
4119 | policy != SCHED_NORMAL && policy != SCHED_BATCH && |
4120 | policy != SCHED_IDLE) | |
b0a9499c | 4121 | return -EINVAL; |
1da177e4 LT |
4122 | /* |
4123 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4124 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4125 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
4126 | */ |
4127 | if (param->sched_priority < 0 || | |
95cdf3b7 | 4128 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 4129 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4130 | return -EINVAL; |
e05606d3 | 4131 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
4132 | return -EINVAL; |
4133 | ||
37e4ab3f OC |
4134 | /* |
4135 | * Allow unprivileged RT tasks to decrease priority: | |
4136 | */ | |
4137 | if (!capable(CAP_SYS_NICE)) { | |
e05606d3 | 4138 | if (rt_policy(policy)) { |
8dc3e909 | 4139 | unsigned long rlim_rtprio; |
8dc3e909 ON |
4140 | |
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); | |
4145 | ||
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 | } | |
dd41f596 IM |
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; | |
5fe1d75f | 4161 | |
37e4ab3f OC |
4162 | /* can't change other user's priorities */ |
4163 | if ((current->euid != p->euid) && | |
4164 | (current->euid != p->uid)) | |
4165 | return -EPERM; | |
4166 | } | |
1da177e4 LT |
4167 | |
4168 | retval = security_task_setscheduler(p, policy, param); | |
4169 | if (retval) | |
4170 | return retval; | |
b29739f9 IM |
4171 | /* |
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); | |
1da177e4 LT |
4176 | /* |
4177 | * To be able to change p->policy safely, the apropriate | |
4178 | * runqueue lock must be held. | |
4179 | */ | |
b29739f9 | 4180 | rq = __task_rq_lock(p); |
1da177e4 LT |
4181 | /* recheck policy now with rq lock held */ |
4182 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4183 | policy = oldpolicy = -1; | |
b29739f9 IM |
4184 | __task_rq_unlock(rq); |
4185 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
1da177e4 LT |
4186 | goto recheck; |
4187 | } | |
dd41f596 IM |
4188 | on_rq = p->se.on_rq; |
4189 | if (on_rq) | |
4190 | deactivate_task(rq, p, 0); | |
1da177e4 | 4191 | oldprio = p->prio; |
dd41f596 IM |
4192 | __setscheduler(rq, p, policy, param->sched_priority); |
4193 | if (on_rq) { | |
4194 | activate_task(rq, p, 0); | |
1da177e4 LT |
4195 | /* |
4196 | * Reschedule if we are currently running on this runqueue and | |
d5f9f942 AM |
4197 | * our priority decreased, or if we are not currently running on |
4198 | * this runqueue and our priority is higher than the current's | |
1da177e4 | 4199 | */ |
d5f9f942 AM |
4200 | if (task_running(rq, p)) { |
4201 | if (p->prio > oldprio) | |
4202 | resched_task(rq->curr); | |
dd41f596 IM |
4203 | } else { |
4204 | check_preempt_curr(rq, p); | |
4205 | } | |
1da177e4 | 4206 | } |
b29739f9 IM |
4207 | __task_rq_unlock(rq); |
4208 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
4209 | ||
95e02ca9 TG |
4210 | rt_mutex_adjust_pi(p); |
4211 | ||
1da177e4 LT |
4212 | return 0; |
4213 | } | |
4214 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
4215 | ||
95cdf3b7 IM |
4216 | static int |
4217 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4218 | { |
1da177e4 LT |
4219 | struct sched_param lparam; |
4220 | struct task_struct *p; | |
36c8b586 | 4221 | int retval; |
1da177e4 LT |
4222 | |
4223 | if (!param || pid < 0) | |
4224 | return -EINVAL; | |
4225 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4226 | return -EFAULT; | |
5fe1d75f ON |
4227 | |
4228 | rcu_read_lock(); | |
4229 | retval = -ESRCH; | |
1da177e4 | 4230 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4231 | if (p != NULL) |
4232 | retval = sched_setscheduler(p, policy, &lparam); | |
4233 | rcu_read_unlock(); | |
36c8b586 | 4234 | |
1da177e4 LT |
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 | { | |
c21761f1 JB |
4247 | /* negative values for policy are not valid */ |
4248 | if (policy < 0) | |
4249 | return -EINVAL; | |
4250 | ||
1da177e4 LT |
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 | { | |
36c8b586 | 4270 | struct task_struct *p; |
1da177e4 | 4271 | int retval = -EINVAL; |
1da177e4 LT |
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; | |
36c8b586 | 4298 | struct task_struct *p; |
1da177e4 | 4299 | int retval = -EINVAL; |
1da177e4 LT |
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 | { | |
1da177e4 | 4332 | cpumask_t cpus_allowed; |
36c8b586 IM |
4333 | struct task_struct *p; |
4334 | int retval; | |
1da177e4 | 4335 | |
5be9361c | 4336 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4337 | read_lock(&tasklist_lock); |
4338 | ||
4339 | p = find_process_by_pid(pid); | |
4340 | if (!p) { | |
4341 | read_unlock(&tasklist_lock); | |
5be9361c | 4342 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
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 | ||
e7834f8f DQ |
4359 | retval = security_task_setscheduler(p, 0, NULL); |
4360 | if (retval) | |
4361 | goto out_unlock; | |
4362 | ||
1da177e4 LT |
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); | |
5be9361c | 4369 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
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 | ||
4cef0c61 | 4410 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
4411 | EXPORT_SYMBOL(cpu_present_map); |
4412 | ||
4413 | #ifndef CONFIG_SMP | |
4cef0c61 | 4414 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 GB |
4415 | EXPORT_SYMBOL(cpu_online_map); |
4416 | ||
4cef0c61 | 4417 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; |
e16b38f7 | 4418 | EXPORT_SYMBOL(cpu_possible_map); |
1da177e4 LT |
4419 | #endif |
4420 | ||
4421 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
4422 | { | |
36c8b586 | 4423 | struct task_struct *p; |
1da177e4 | 4424 | int retval; |
1da177e4 | 4425 | |
5be9361c | 4426 | mutex_lock(&sched_hotcpu_mutex); |
1da177e4 LT |
4427 | read_lock(&tasklist_lock); |
4428 | ||
4429 | retval = -ESRCH; | |
4430 | p = find_process_by_pid(pid); | |
4431 | if (!p) | |
4432 | goto out_unlock; | |
4433 | ||
e7834f8f DQ |
4434 | retval = security_task_getscheduler(p); |
4435 | if (retval) | |
4436 | goto out_unlock; | |
4437 | ||
2f7016d9 | 4438 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
4439 | |
4440 | out_unlock: | |
4441 | read_unlock(&tasklist_lock); | |
5be9361c | 4442 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
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 | * | |
dd41f596 IM |
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. | |
1da177e4 LT |
4479 | */ |
4480 | asmlinkage long sys_sched_yield(void) | |
4481 | { | |
70b97a7f | 4482 | struct rq *rq = this_rq_lock(); |
1da177e4 LT |
4483 | |
4484 | schedstat_inc(rq, yld_cnt); | |
dd41f596 | 4485 | if (unlikely(rq->nr_running == 1)) |
1da177e4 | 4486 | schedstat_inc(rq, yld_act_empty); |
dd41f596 IM |
4487 | else |
4488 | current->sched_class->yield_task(rq, current); | |
1da177e4 LT |
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); | |
8a25d5de | 4495 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4496 | _raw_spin_unlock(&rq->lock); |
4497 | preempt_enable_no_resched(); | |
4498 | ||
4499 | schedule(); | |
4500 | ||
4501 | return 0; | |
4502 | } | |
4503 | ||
e7b38404 | 4504 | static void __cond_resched(void) |
1da177e4 | 4505 | { |
8e0a43d8 IM |
4506 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4507 | __might_sleep(__FILE__, __LINE__); | |
4508 | #endif | |
5bbcfd90 IM |
4509 | /* |
4510 | * The BKS might be reacquired before we have dropped | |
4511 | * PREEMPT_ACTIVE, which could trigger a second | |
4512 | * cond_resched() call. | |
4513 | */ | |
1da177e4 LT |
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 | { | |
9414232f IM |
4523 | if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
4524 | system_state == SYSTEM_RUNNING) { | |
1da177e4 LT |
4525 | __cond_resched(); |
4526 | return 1; | |
4527 | } | |
4528 | return 0; | |
4529 | } | |
1da177e4 LT |
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 | */ | |
95cdf3b7 | 4540 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4541 | { |
6df3cecb JK |
4542 | int ret = 0; |
4543 | ||
1da177e4 LT |
4544 | if (need_lockbreak(lock)) { |
4545 | spin_unlock(lock); | |
4546 | cpu_relax(); | |
6df3cecb | 4547 | ret = 1; |
1da177e4 LT |
4548 | spin_lock(lock); |
4549 | } | |
9414232f | 4550 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
8a25d5de | 4551 | spin_release(&lock->dep_map, 1, _THIS_IP_); |
1da177e4 LT |
4552 | _raw_spin_unlock(lock); |
4553 | preempt_enable_no_resched(); | |
4554 | __cond_resched(); | |
6df3cecb | 4555 | ret = 1; |
1da177e4 | 4556 | spin_lock(lock); |
1da177e4 | 4557 | } |
6df3cecb | 4558 | return ret; |
1da177e4 | 4559 | } |
1da177e4 LT |
4560 | EXPORT_SYMBOL(cond_resched_lock); |
4561 | ||
4562 | int __sched cond_resched_softirq(void) | |
4563 | { | |
4564 | BUG_ON(!in_softirq()); | |
4565 | ||
9414232f | 4566 | if (need_resched() && system_state == SYSTEM_RUNNING) { |
98d82567 | 4567 | local_bh_enable(); |
1da177e4 LT |
4568 | __cond_resched(); |
4569 | local_bh_disable(); | |
4570 | return 1; | |
4571 | } | |
4572 | return 0; | |
4573 | } | |
1da177e4 LT |
4574 | EXPORT_SYMBOL(cond_resched_softirq); |
4575 | ||
1da177e4 LT |
4576 | /** |
4577 | * yield - yield the current processor to other threads. | |
4578 | * | |
72fd4a35 | 4579 | * This is a shortcut for kernel-space yielding - it marks the |
1da177e4 LT |
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 | } | |
1da177e4 LT |
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 | { | |
70b97a7f | 4598 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 | 4599 | |
0ff92245 | 4600 | delayacct_blkio_start(); |
1da177e4 LT |
4601 | atomic_inc(&rq->nr_iowait); |
4602 | schedule(); | |
4603 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4604 | delayacct_blkio_end(); |
1da177e4 | 4605 | } |
1da177e4 LT |
4606 | EXPORT_SYMBOL(io_schedule); |
4607 | ||
4608 | long __sched io_schedule_timeout(long timeout) | |
4609 | { | |
70b97a7f | 4610 | struct rq *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4611 | long ret; |
4612 | ||
0ff92245 | 4613 | delayacct_blkio_start(); |
1da177e4 LT |
4614 | atomic_inc(&rq->nr_iowait); |
4615 | ret = schedule_timeout(timeout); | |
4616 | atomic_dec(&rq->nr_iowait); | |
0ff92245 | 4617 | delayacct_blkio_end(); |
1da177e4 LT |
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: | |
b0a9499c | 4638 | case SCHED_BATCH: |
dd41f596 | 4639 | case SCHED_IDLE: |
1da177e4 LT |
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: | |
b0a9499c | 4663 | case SCHED_BATCH: |
dd41f596 | 4664 | case SCHED_IDLE: |
1da177e4 LT |
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 | { | |
36c8b586 | 4681 | struct task_struct *p; |
1da177e4 LT |
4682 | int retval = -EINVAL; |
4683 | struct timespec t; | |
1da177e4 LT |
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 | ||
b78709cf | 4698 | jiffies_to_timespec(p->policy == SCHED_FIFO ? |
dd41f596 | 4699 | 0 : static_prio_timeslice(p->static_prio), &t); |
1da177e4 LT |
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 | ||
2ed6e34f | 4709 | static const char stat_nam[] = "RSDTtZX"; |
36c8b586 IM |
4710 | |
4711 | static void show_task(struct task_struct *p) | |
1da177e4 | 4712 | { |
1da177e4 | 4713 | unsigned long free = 0; |
36c8b586 | 4714 | unsigned state; |
1da177e4 | 4715 | |
1da177e4 | 4716 | state = p->state ? __ffs(p->state) + 1 : 0; |
2ed6e34f AM |
4717 | printk("%-13.13s %c", p->comm, |
4718 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); | |
1da177e4 LT |
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 | { | |
10ebffde | 4732 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4733 | while (!*n) |
4734 | n++; | |
10ebffde | 4735 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4736 | } |
4737 | #endif | |
35f6f753 | 4738 | printk("%5lu %5d %6d", free, p->pid, p->parent->pid); |
1da177e4 LT |
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 | ||
e59e2ae2 | 4748 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4749 | { |
36c8b586 | 4750 | struct task_struct *g, *p; |
1da177e4 LT |
4751 | |
4752 | #if (BITS_PER_LONG == 32) | |
4753 | printk("\n" | |
301827ac CC |
4754 | " free sibling\n"); |
4755 | printk(" task PC stack pid father child younger older\n"); | |
1da177e4 LT |
4756 | #else |
4757 | printk("\n" | |
301827ac CC |
4758 | " free sibling\n"); |
4759 | printk(" task PC stack pid father child younger older\n"); | |
1da177e4 LT |
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(); | |
39bc89fd | 4768 | if (!state_filter || (p->state & state_filter)) |
e59e2ae2 | 4769 | show_task(p); |
1da177e4 LT |
4770 | } while_each_thread(g, p); |
4771 | ||
04c9167f JF |
4772 | touch_all_softlockup_watchdogs(); |
4773 | ||
dd41f596 IM |
4774 | #ifdef CONFIG_SCHED_DEBUG |
4775 | sysrq_sched_debug_show(); | |
4776 | #endif | |
1da177e4 | 4777 | read_unlock(&tasklist_lock); |
e59e2ae2 IM |
4778 | /* |
4779 | * Only show locks if all tasks are dumped: | |
4780 | */ | |
4781 | if (state_filter == -1) | |
4782 | debug_show_all_locks(); | |
1da177e4 LT |
4783 | } |
4784 | ||
1df21055 IM |
4785 | void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
4786 | { | |
dd41f596 | 4787 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4788 | } |
4789 | ||
f340c0d1 IM |
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 | */ | |
5c1e1767 | 4798 | void __cpuinit init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4799 | { |
70b97a7f | 4800 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4801 | unsigned long flags; |
4802 | ||
dd41f596 IM |
4803 | __sched_fork(idle); |
4804 | idle->se.exec_start = sched_clock(); | |
4805 | ||
b29739f9 | 4806 | idle->prio = idle->normal_prio = MAX_PRIO; |
1da177e4 | 4807 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
dd41f596 | 4808 | __set_task_cpu(idle, cpu); |
1da177e4 LT |
4809 | |
4810 | spin_lock_irqsave(&rq->lock, flags); | |
4811 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4812 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4813 | idle->oncpu = 1; | |
4814 | #endif | |
1da177e4 LT |
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) | |
a1261f54 | 4819 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4820 | #else |
a1261f54 | 4821 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 | 4822 | #endif |
dd41f596 IM |
4823 | /* |
4824 | * The idle tasks have their own, simple scheduling class: | |
4825 | */ | |
4826 | idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
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 | ||
dd41f596 IM |
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 | ||
1da177e4 LT |
4860 | #ifdef CONFIG_SMP |
4861 | /* | |
4862 | * This is how migration works: | |
4863 | * | |
70b97a7f | 4864 | * 1) we queue a struct migration_req structure in the source CPU's |
1da177e4 LT |
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 | */ | |
36c8b586 | 4886 | int set_cpus_allowed(struct task_struct *p, cpumask_t new_mask) |
1da177e4 | 4887 | { |
70b97a7f | 4888 | struct migration_req req; |
1da177e4 | 4889 | unsigned long flags; |
70b97a7f | 4890 | struct rq *rq; |
48f24c4d | 4891 | int ret = 0; |
1da177e4 LT |
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); | |
48f24c4d | 4914 | |
1da177e4 LT |
4915 | return ret; |
4916 | } | |
1da177e4 LT |
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. | |
efc30814 KK |
4927 | * |
4928 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4929 | */ |
efc30814 | 4930 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 4931 | { |
70b97a7f | 4932 | struct rq *rq_dest, *rq_src; |
dd41f596 | 4933 | int ret = 0, on_rq; |
1da177e4 LT |
4934 | |
4935 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 4936 | return ret; |
1da177e4 LT |
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 | ||
dd41f596 IM |
4949 | on_rq = p->se.on_rq; |
4950 | if (on_rq) | |
4951 | deactivate_task(rq_src, p, 0); | |
1da177e4 | 4952 | set_task_cpu(p, dest_cpu); |
dd41f596 IM |
4953 | if (on_rq) { |
4954 | activate_task(rq_dest, p, 0); | |
4955 | check_preempt_curr(rq_dest, p); | |
1da177e4 | 4956 | } |
efc30814 | 4957 | ret = 1; |
1da177e4 LT |
4958 | out: |
4959 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 4960 | return ret; |
1da177e4 LT |
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 | */ | |
95cdf3b7 | 4968 | static int migration_thread(void *data) |
1da177e4 | 4969 | { |
1da177e4 | 4970 | int cpu = (long)data; |
70b97a7f | 4971 | struct rq *rq; |
1da177e4 LT |
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()) { | |
70b97a7f | 4978 | struct migration_req *req; |
1da177e4 | 4979 | struct list_head *head; |
1da177e4 | 4980 | |
3e1d1d28 | 4981 | try_to_freeze(); |
1da177e4 LT |
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 | } | |
70b97a7f | 5003 | req = list_entry(head->next, struct migration_req, list); |
1da177e4 LT |
5004 | list_del_init(head->next); |
5005 | ||
674311d5 NP |
5006 | spin_unlock(&rq->lock); |
5007 | __migrate_task(req->task, cpu, req->dest_cpu); | |
5008 | local_irq_enable(); | |
1da177e4 LT |
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 | |
054b9108 KK |
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 | */ | |
48f24c4d | 5031 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
1da177e4 | 5032 | { |
efc30814 | 5033 | unsigned long flags; |
1da177e4 | 5034 | cpumask_t mask; |
70b97a7f IM |
5035 | struct rq *rq; |
5036 | int dest_cpu; | |
1da177e4 | 5037 | |
efc30814 | 5038 | restart: |
1da177e4 LT |
5039 | /* On same node? */ |
5040 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
48f24c4d | 5041 | cpus_and(mask, mask, p->cpus_allowed); |
1da177e4 LT |
5042 | dest_cpu = any_online_cpu(mask); |
5043 | ||
5044 | /* On any allowed CPU? */ | |
5045 | if (dest_cpu == NR_CPUS) | |
48f24c4d | 5046 | dest_cpu = any_online_cpu(p->cpus_allowed); |
1da177e4 LT |
5047 | |
5048 | /* No more Mr. Nice Guy. */ | |
5049 | if (dest_cpu == NR_CPUS) { | |
48f24c4d IM |
5050 | rq = task_rq_lock(p, &flags); |
5051 | cpus_setall(p->cpus_allowed); | |
5052 | dest_cpu = any_online_cpu(p->cpus_allowed); | |
efc30814 | 5053 | task_rq_unlock(rq, &flags); |
1da177e4 LT |
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 | */ | |
48f24c4d | 5060 | if (p->mm && printk_ratelimit()) |
1da177e4 LT |
5061 | printk(KERN_INFO "process %d (%s) no " |
5062 | "longer affine to cpu%d\n", | |
48f24c4d | 5063 | p->pid, p->comm, dead_cpu); |
1da177e4 | 5064 | } |
48f24c4d | 5065 | if (!__migrate_task(p, dead_cpu, dest_cpu)) |
efc30814 | 5066 | goto restart; |
1da177e4 LT |
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 | */ | |
70b97a7f | 5076 | static void migrate_nr_uninterruptible(struct rq *rq_src) |
1da177e4 | 5077 | { |
70b97a7f | 5078 | struct rq *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
1da177e4 LT |
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 | { | |
48f24c4d | 5092 | struct task_struct *p, *t; |
1da177e4 LT |
5093 | |
5094 | write_lock_irq(&tasklist_lock); | |
5095 | ||
48f24c4d IM |
5096 | do_each_thread(t, p) { |
5097 | if (p == current) | |
1da177e4 LT |
5098 | continue; |
5099 | ||
48f24c4d IM |
5100 | if (task_cpu(p) == src_cpu) |
5101 | move_task_off_dead_cpu(src_cpu, p); | |
5102 | } while_each_thread(t, p); | |
1da177e4 LT |
5103 | |
5104 | write_unlock_irq(&tasklist_lock); | |
5105 | } | |
5106 | ||
dd41f596 IM |
5107 | /* |
5108 | * Schedules idle task to be the next runnable task on current CPU. | |
1da177e4 | 5109 | * It does so by boosting its priority to highest possible and adding it to |
48f24c4d | 5110 | * the _front_ of the runqueue. Used by CPU offline code. |
1da177e4 LT |
5111 | */ |
5112 | void sched_idle_next(void) | |
5113 | { | |
48f24c4d | 5114 | int this_cpu = smp_processor_id(); |
70b97a7f | 5115 | struct rq *rq = cpu_rq(this_cpu); |
1da177e4 LT |
5116 | struct task_struct *p = rq->idle; |
5117 | unsigned long flags; | |
5118 | ||
5119 | /* cpu has to be offline */ | |
48f24c4d | 5120 | BUG_ON(cpu_online(this_cpu)); |
1da177e4 | 5121 | |
48f24c4d IM |
5122 | /* |
5123 | * Strictly not necessary since rest of the CPUs are stopped by now | |
5124 | * and interrupts disabled on the current cpu. | |
1da177e4 LT |
5125 | */ |
5126 | spin_lock_irqsave(&rq->lock, flags); | |
5127 | ||
dd41f596 | 5128 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
48f24c4d IM |
5129 | |
5130 | /* Add idle task to the _front_ of its priority queue: */ | |
dd41f596 | 5131 | activate_idle_task(p, rq); |
1da177e4 LT |
5132 | |
5133 | spin_unlock_irqrestore(&rq->lock, flags); | |
5134 | } | |
5135 | ||
48f24c4d IM |
5136 | /* |
5137 | * Ensures that the idle task is using init_mm right before its cpu goes | |
1da177e4 LT |
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 | ||
054b9108 | 5151 | /* called under rq->lock with disabled interrupts */ |
36c8b586 | 5152 | static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
1da177e4 | 5153 | { |
70b97a7f | 5154 | struct rq *rq = cpu_rq(dead_cpu); |
1da177e4 LT |
5155 | |
5156 | /* Must be exiting, otherwise would be on tasklist. */ | |
48f24c4d | 5157 | BUG_ON(p->exit_state != EXIT_ZOMBIE && p->exit_state != EXIT_DEAD); |
1da177e4 LT |
5158 | |
5159 | /* Cannot have done final schedule yet: would have vanished. */ | |
c394cc9f | 5160 | BUG_ON(p->state == TASK_DEAD); |
1da177e4 | 5161 | |
48f24c4d | 5162 | get_task_struct(p); |
1da177e4 LT |
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. | |
054b9108 | 5168 | * NOTE: interrupts should be left disabled --dev@ |
1da177e4 | 5169 | */ |
054b9108 | 5170 | spin_unlock(&rq->lock); |
48f24c4d | 5171 | move_task_off_dead_cpu(dead_cpu, p); |
054b9108 | 5172 | spin_lock(&rq->lock); |
1da177e4 | 5173 | |
48f24c4d | 5174 | put_task_struct(p); |
1da177e4 LT |
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 | { | |
70b97a7f | 5180 | struct rq *rq = cpu_rq(dead_cpu); |
dd41f596 | 5181 | struct task_struct *next; |
48f24c4d | 5182 | |
dd41f596 IM |
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); | |
1da177e4 LT |
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 | */ | |
48f24c4d IM |
5198 | static int __cpuinit |
5199 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
1da177e4 | 5200 | { |
1da177e4 | 5201 | struct task_struct *p; |
48f24c4d | 5202 | int cpu = (long)hcpu; |
1da177e4 | 5203 | unsigned long flags; |
70b97a7f | 5204 | struct rq *rq; |
1da177e4 LT |
5205 | |
5206 | switch (action) { | |
5be9361c GS |
5207 | case CPU_LOCK_ACQUIRE: |
5208 | mutex_lock(&sched_hotcpu_mutex); | |
5209 | break; | |
5210 | ||
1da177e4 | 5211 | case CPU_UP_PREPARE: |
8bb78442 | 5212 | case CPU_UP_PREPARE_FROZEN: |
dd41f596 | 5213 | p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
1da177e4 LT |
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); | |
dd41f596 | 5220 | __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
1da177e4 LT |
5221 | task_rq_unlock(rq, &flags); |
5222 | cpu_rq(cpu)->migration_thread = p; | |
5223 | break; | |
48f24c4d | 5224 | |
1da177e4 | 5225 | case CPU_ONLINE: |
8bb78442 | 5226 | case CPU_ONLINE_FROZEN: |
1da177e4 LT |
5227 | /* Strictly unneccessary, as first user will wake it. */ |
5228 | wake_up_process(cpu_rq(cpu)->migration_thread); | |
5229 | break; | |
48f24c4d | 5230 | |
1da177e4 LT |
5231 | #ifdef CONFIG_HOTPLUG_CPU |
5232 | case CPU_UP_CANCELED: | |
8bb78442 | 5233 | case CPU_UP_CANCELED_FROZEN: |
fc75cdfa HC |
5234 | if (!cpu_rq(cpu)->migration_thread) |
5235 | break; | |
1da177e4 | 5236 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
5237 | kthread_bind(cpu_rq(cpu)->migration_thread, |
5238 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
5239 | kthread_stop(cpu_rq(cpu)->migration_thread); |
5240 | cpu_rq(cpu)->migration_thread = NULL; | |
5241 | break; | |
48f24c4d | 5242 | |
1da177e4 | 5243 | case CPU_DEAD: |
8bb78442 | 5244 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
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); | |
dd41f596 | 5251 | deactivate_task(rq, rq->idle, 0); |
1da177e4 | 5252 | rq->idle->static_prio = MAX_PRIO; |
dd41f596 IM |
5253 | __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
5254 | rq->idle->sched_class = &idle_sched_class; | |
1da177e4 LT |
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 | |
5be9361c | 5261 | * they didn't take sched_hotcpu_mutex. Just wake up |
1da177e4 LT |
5262 | * the requestors. */ |
5263 | spin_lock_irq(&rq->lock); | |
5264 | while (!list_empty(&rq->migration_queue)) { | |
70b97a7f IM |
5265 | struct migration_req *req; |
5266 | ||
1da177e4 | 5267 | req = list_entry(rq->migration_queue.next, |
70b97a7f | 5268 | struct migration_req, list); |
1da177e4 LT |
5269 | list_del_init(&req->list); |
5270 | complete(&req->done); | |
5271 | } | |
5272 | spin_unlock_irq(&rq->lock); | |
5273 | break; | |
5274 | #endif | |
5be9361c GS |
5275 | case CPU_LOCK_RELEASE: |
5276 | mutex_unlock(&sched_hotcpu_mutex); | |
5277 | break; | |
1da177e4 LT |
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 | */ | |
26c2143b | 5285 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
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(); | |
07dccf33 | 5293 | int err; |
48f24c4d IM |
5294 | |
5295 | /* Start one for the boot CPU: */ | |
07dccf33 AM |
5296 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5297 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5298 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5299 | register_cpu_notifier(&migration_notifier); | |
48f24c4d | 5300 | |
1da177e4 LT |
5301 | return 0; |
5302 | } | |
5303 | #endif | |
5304 | ||
5305 | #ifdef CONFIG_SMP | |
476f3534 CL |
5306 | |
5307 | /* Number of possible processor ids */ | |
5308 | int nr_cpu_ids __read_mostly = NR_CPUS; | |
5309 | EXPORT_SYMBOL(nr_cpu_ids); | |
5310 | ||
1a20ff27 | 5311 | #undef SCHED_DOMAIN_DEBUG |
1da177e4 LT |
5312 | #ifdef SCHED_DOMAIN_DEBUG |
5313 | static void sched_domain_debug(struct sched_domain *sd, int cpu) | |
5314 | { | |
5315 | int level = 0; | |
5316 | ||
41c7ce9a NP |
5317 | if (!sd) { |
5318 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5319 | return; | |
5320 | } | |
5321 | ||
1da177e4 LT |
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) | |
33859f7f MOS |
5341 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5342 | " has parent"); | |
1da177e4 LT |
5343 | break; |
5344 | } | |
5345 | ||
5346 | printk("span %s\n", str); | |
5347 | ||
5348 | if (!cpu_isset(cpu, sd->span)) | |
33859f7f MOS |
5349 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5350 | "CPU%d\n", cpu); | |
1da177e4 | 5351 | if (!cpu_isset(cpu, group->cpumask)) |
33859f7f MOS |
5352 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5353 | " CPU%d\n", cpu); | |
1da177e4 LT |
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 | ||
5517d86b | 5366 | if (!group->__cpu_power) { |
1da177e4 | 5367 | printk("\n"); |
33859f7f MOS |
5368 | printk(KERN_ERR "ERROR: domain->cpu_power not " |
5369 | "set\n"); | |
1da177e4 LT |
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)) | |
33859f7f MOS |
5392 | printk(KERN_ERR "ERROR: groups don't span " |
5393 | "domain->span\n"); | |
1da177e4 LT |
5394 | |
5395 | level++; | |
5396 | sd = sd->parent; | |
33859f7f MOS |
5397 | if (!sd) |
5398 | continue; | |
1da177e4 | 5399 | |
33859f7f MOS |
5400 | if (!cpus_subset(groupmask, sd->span)) |
5401 | printk(KERN_ERR "ERROR: parent span is not a superset " | |
5402 | "of domain->span\n"); | |
1da177e4 LT |
5403 | |
5404 | } while (sd); | |
5405 | } | |
5406 | #else | |
48f24c4d | 5407 | # define sched_domain_debug(sd, cpu) do { } while (0) |
1da177e4 LT |
5408 | #endif |
5409 | ||
1a20ff27 | 5410 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
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 | | |
89c4710e SS |
5419 | SD_BALANCE_EXEC | |
5420 | SD_SHARE_CPUPOWER | | |
5421 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
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 | ||
48f24c4d IM |
5435 | static int |
5436 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
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 | | |
89c4710e SS |
5455 | SD_BALANCE_EXEC | |
5456 | SD_SHARE_CPUPOWER | | |
5457 | SD_SHARE_PKG_RESOURCES); | |
245af2c7 SS |
5458 | } |
5459 | if (~cflags & pflags) | |
5460 | return 0; | |
5461 | ||
5462 | return 1; | |
5463 | } | |
5464 | ||
1da177e4 LT |
5465 | /* |
5466 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
5467 | * hold the hotplug lock. | |
5468 | */ | |
9c1cfda2 | 5469 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 5470 | { |
70b97a7f | 5471 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
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; | |
1a848870 | 5479 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5480 | tmp->parent = parent->parent; |
1a848870 SS |
5481 | if (parent->parent) |
5482 | parent->parent->child = tmp; | |
5483 | } | |
245af2c7 SS |
5484 | } |
5485 | ||
1a848870 | 5486 | if (sd && sd_degenerate(sd)) { |
245af2c7 | 5487 | sd = sd->parent; |
1a848870 SS |
5488 | if (sd) |
5489 | sd->child = NULL; | |
5490 | } | |
1da177e4 LT |
5491 | |
5492 | sched_domain_debug(sd, cpu); | |
5493 | ||
674311d5 | 5494 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
5495 | } |
5496 | ||
5497 | /* cpus with isolated domains */ | |
67af63a6 | 5498 | static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
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 | /* | |
6711cab4 SS |
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). | |
1da177e4 LT |
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 | */ | |
a616058b | 5525 | static void |
6711cab4 SS |
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)) | |
1da177e4 LT |
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) { | |
6711cab4 SS |
5535 | struct sched_group *sg; |
5536 | int group = group_fn(i, cpu_map, &sg); | |
1da177e4 LT |
5537 | int j; |
5538 | ||
5539 | if (cpu_isset(i, covered)) | |
5540 | continue; | |
5541 | ||
5542 | sg->cpumask = CPU_MASK_NONE; | |
5517d86b | 5543 | sg->__cpu_power = 0; |
1da177e4 LT |
5544 | |
5545 | for_each_cpu_mask(j, span) { | |
6711cab4 | 5546 | if (group_fn(j, cpu_map, NULL) != group) |
1da177e4 LT |
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 | ||
9c1cfda2 | 5561 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5562 | |
9c1cfda2 | 5563 | #ifdef CONFIG_NUMA |
198e2f18 | 5564 | |
9c1cfda2 JH |
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 | { | |
9c1cfda2 | 5616 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); |
48f24c4d IM |
5617 | cpumask_t span, nodemask; |
5618 | int i; | |
9c1cfda2 JH |
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); | |
48f24c4d | 5629 | |
9c1cfda2 JH |
5630 | nodemask = node_to_cpumask(next_node); |
5631 | cpus_or(span, span, nodemask); | |
5632 | } | |
5633 | ||
5634 | return span; | |
5635 | } | |
5636 | #endif | |
5637 | ||
5c45bf27 | 5638 | int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
48f24c4d | 5639 | |
9c1cfda2 | 5640 | /* |
48f24c4d | 5641 | * SMT sched-domains: |
9c1cfda2 | 5642 | */ |
1da177e4 LT |
5643 | #ifdef CONFIG_SCHED_SMT |
5644 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
6711cab4 | 5645 | static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
48f24c4d | 5646 | |
6711cab4 SS |
5647 | static int cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, |
5648 | struct sched_group **sg) | |
1da177e4 | 5649 | { |
6711cab4 SS |
5650 | if (sg) |
5651 | *sg = &per_cpu(sched_group_cpus, cpu); | |
1da177e4 LT |
5652 | return cpu; |
5653 | } | |
5654 | #endif | |
5655 | ||
48f24c4d IM |
5656 | /* |
5657 | * multi-core sched-domains: | |
5658 | */ | |
1e9f28fa SS |
5659 | #ifdef CONFIG_SCHED_MC |
5660 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
6711cab4 | 5661 | static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
1e9f28fa SS |
5662 | #endif |
5663 | ||
5664 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
6711cab4 SS |
5665 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5666 | struct sched_group **sg) | |
1e9f28fa | 5667 | { |
6711cab4 | 5668 | int group; |
a616058b SS |
5669 | cpumask_t mask = cpu_sibling_map[cpu]; |
5670 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 SS |
5671 | group = first_cpu(mask); |
5672 | if (sg) | |
5673 | *sg = &per_cpu(sched_group_core, group); | |
5674 | return group; | |
1e9f28fa SS |
5675 | } |
5676 | #elif defined(CONFIG_SCHED_MC) | |
6711cab4 SS |
5677 | static int cpu_to_core_group(int cpu, const cpumask_t *cpu_map, |
5678 | struct sched_group **sg) | |
1e9f28fa | 5679 | { |
6711cab4 SS |
5680 | if (sg) |
5681 | *sg = &per_cpu(sched_group_core, cpu); | |
1e9f28fa SS |
5682 | return cpu; |
5683 | } | |
5684 | #endif | |
5685 | ||
1da177e4 | 5686 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
6711cab4 | 5687 | static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
48f24c4d | 5688 | |
6711cab4 SS |
5689 | static int cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, |
5690 | struct sched_group **sg) | |
1da177e4 | 5691 | { |
6711cab4 | 5692 | int group; |
48f24c4d | 5693 | #ifdef CONFIG_SCHED_MC |
1e9f28fa | 5694 | cpumask_t mask = cpu_coregroup_map(cpu); |
a616058b | 5695 | cpus_and(mask, mask, *cpu_map); |
6711cab4 | 5696 | group = first_cpu(mask); |
1e9f28fa | 5697 | #elif defined(CONFIG_SCHED_SMT) |
a616058b SS |
5698 | cpumask_t mask = cpu_sibling_map[cpu]; |
5699 | cpus_and(mask, mask, *cpu_map); | |
6711cab4 | 5700 | group = first_cpu(mask); |
1da177e4 | 5701 | #else |
6711cab4 | 5702 | group = cpu; |
1da177e4 | 5703 | #endif |
6711cab4 SS |
5704 | if (sg) |
5705 | *sg = &per_cpu(sched_group_phys, group); | |
5706 | return group; | |
1da177e4 LT |
5707 | } |
5708 | ||
5709 | #ifdef CONFIG_NUMA | |
1da177e4 | 5710 | /* |
9c1cfda2 JH |
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. | |
1da177e4 | 5714 | */ |
9c1cfda2 | 5715 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 5716 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 5717 | |
9c1cfda2 | 5718 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
6711cab4 | 5719 | static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
9c1cfda2 | 5720 | |
6711cab4 SS |
5721 | static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
5722 | struct sched_group **sg) | |
9c1cfda2 | 5723 | { |
6711cab4 SS |
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; | |
1da177e4 | 5733 | } |
6711cab4 | 5734 | |
08069033 SS |
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 | ||
5517d86b | 5755 | sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
08069033 SS |
5756 | } |
5757 | sg = sg->next; | |
5758 | if (sg != group_head) | |
5759 | goto next_sg; | |
5760 | } | |
1da177e4 LT |
5761 | #endif |
5762 | ||
a616058b | 5763 | #ifdef CONFIG_NUMA |
51888ca2 SV |
5764 | /* Free memory allocated for various sched_group structures */ |
5765 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5766 | { | |
a616058b | 5767 | int cpu, i; |
51888ca2 SV |
5768 | |
5769 | for_each_cpu_mask(cpu, *cpu_map) { | |
51888ca2 SV |
5770 | struct sched_group **sched_group_nodes |
5771 | = sched_group_nodes_bycpu[cpu]; | |
5772 | ||
51888ca2 SV |
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 | } | |
51888ca2 | 5797 | } |
a616058b SS |
5798 | #else |
5799 | static void free_sched_groups(const cpumask_t *cpu_map) | |
5800 | { | |
5801 | } | |
5802 | #endif | |
51888ca2 | 5803 | |
89c4710e SS |
5804 | /* |
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 | ||
5517d86b ED |
5830 | sd->groups->__cpu_power = 0; |
5831 | ||
89c4710e SS |
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)))) { | |
5517d86b | 5842 | sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
89c4710e SS |
5843 | return; |
5844 | } | |
5845 | ||
89c4710e SS |
5846 | /* |
5847 | * add cpu_power of each child group to this groups cpu_power | |
5848 | */ | |
5849 | group = child->groups; | |
5850 | do { | |
5517d86b | 5851 | sg_inc_cpu_power(sd->groups, group->__cpu_power); |
89c4710e SS |
5852 | group = group->next; |
5853 | } while (group != child->groups); | |
5854 | } | |
5855 | ||
1da177e4 | 5856 | /* |
1a20ff27 DG |
5857 | * Build sched domains for a given set of cpus and attach the sched domains |
5858 | * to the individual cpus | |
1da177e4 | 5859 | */ |
51888ca2 | 5860 | static int build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
5861 | { |
5862 | int i; | |
d1b55138 JH |
5863 | #ifdef CONFIG_NUMA |
5864 | struct sched_group **sched_group_nodes = NULL; | |
6711cab4 | 5865 | int sd_allnodes = 0; |
d1b55138 JH |
5866 | |
5867 | /* | |
5868 | * Allocate the per-node list of sched groups | |
5869 | */ | |
dd41f596 | 5870 | sched_group_nodes = kzalloc(sizeof(struct sched_group *)*MAX_NUMNODES, |
d3a5aa98 | 5871 | GFP_KERNEL); |
d1b55138 JH |
5872 | if (!sched_group_nodes) { |
5873 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
51888ca2 | 5874 | return -ENOMEM; |
d1b55138 JH |
5875 | } |
5876 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
5877 | #endif | |
1da177e4 LT |
5878 | |
5879 | /* | |
1a20ff27 | 5880 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 5881 | */ |
1a20ff27 | 5882 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5883 | struct sched_domain *sd = NULL, *p; |
5884 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
5885 | ||
1a20ff27 | 5886 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5887 | |
5888 | #ifdef CONFIG_NUMA | |
dd41f596 IM |
5889 | if (cpus_weight(*cpu_map) > |
5890 | SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { | |
9c1cfda2 JH |
5891 | sd = &per_cpu(allnodes_domains, i); |
5892 | *sd = SD_ALLNODES_INIT; | |
5893 | sd->span = *cpu_map; | |
6711cab4 | 5894 | cpu_to_allnodes_group(i, cpu_map, &sd->groups); |
9c1cfda2 | 5895 | p = sd; |
6711cab4 | 5896 | sd_allnodes = 1; |
9c1cfda2 JH |
5897 | } else |
5898 | p = NULL; | |
5899 | ||
1da177e4 | 5900 | sd = &per_cpu(node_domains, i); |
1da177e4 | 5901 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
5902 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
5903 | sd->parent = p; | |
1a848870 SS |
5904 | if (p) |
5905 | p->child = sd; | |
9c1cfda2 | 5906 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
5907 | #endif |
5908 | ||
5909 | p = sd; | |
5910 | sd = &per_cpu(phys_domains, i); | |
1da177e4 LT |
5911 | *sd = SD_CPU_INIT; |
5912 | sd->span = nodemask; | |
5913 | sd->parent = p; | |
1a848870 SS |
5914 | if (p) |
5915 | p->child = sd; | |
6711cab4 | 5916 | cpu_to_phys_group(i, cpu_map, &sd->groups); |
1da177e4 | 5917 | |
1e9f28fa SS |
5918 | #ifdef CONFIG_SCHED_MC |
5919 | p = sd; | |
5920 | sd = &per_cpu(core_domains, i); | |
1e9f28fa SS |
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; | |
1a848870 | 5925 | p->child = sd; |
6711cab4 | 5926 | cpu_to_core_group(i, cpu_map, &sd->groups); |
1e9f28fa SS |
5927 | #endif |
5928 | ||
1da177e4 LT |
5929 | #ifdef CONFIG_SCHED_SMT |
5930 | p = sd; | |
5931 | sd = &per_cpu(cpu_domains, i); | |
1da177e4 LT |
5932 | *sd = SD_SIBLING_INIT; |
5933 | sd->span = cpu_sibling_map[i]; | |
1a20ff27 | 5934 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 | 5935 | sd->parent = p; |
1a848870 | 5936 | p->child = sd; |
6711cab4 | 5937 | cpu_to_cpu_group(i, cpu_map, &sd->groups); |
1da177e4 LT |
5938 | #endif |
5939 | } | |
5940 | ||
5941 | #ifdef CONFIG_SCHED_SMT | |
5942 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 5943 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 | 5944 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
1a20ff27 | 5945 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
5946 | if (i != first_cpu(this_sibling_map)) |
5947 | continue; | |
5948 | ||
dd41f596 IM |
5949 | init_sched_build_groups(this_sibling_map, cpu_map, |
5950 | &cpu_to_cpu_group); | |
1da177e4 LT |
5951 | } |
5952 | #endif | |
5953 | ||
1e9f28fa SS |
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; | |
dd41f596 IM |
5961 | init_sched_build_groups(this_core_map, cpu_map, |
5962 | &cpu_to_core_group); | |
1e9f28fa SS |
5963 | } |
5964 | #endif | |
5965 | ||
1da177e4 LT |
5966 | /* Set up physical groups */ |
5967 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5968 | cpumask_t nodemask = node_to_cpumask(i); | |
5969 | ||
1a20ff27 | 5970 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5971 | if (cpus_empty(nodemask)) |
5972 | continue; | |
5973 | ||
6711cab4 | 5974 | init_sched_build_groups(nodemask, cpu_map, &cpu_to_phys_group); |
1da177e4 LT |
5975 | } |
5976 | ||
5977 | #ifdef CONFIG_NUMA | |
5978 | /* Set up node groups */ | |
6711cab4 | 5979 | if (sd_allnodes) |
dd41f596 IM |
5980 | init_sched_build_groups(*cpu_map, cpu_map, |
5981 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
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); | |
d1b55138 JH |
5992 | if (cpus_empty(nodemask)) { |
5993 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 5994 | continue; |
d1b55138 | 5995 | } |
9c1cfda2 JH |
5996 | |
5997 | domainspan = sched_domain_node_span(i); | |
5998 | cpus_and(domainspan, domainspan, *cpu_map); | |
5999 | ||
15f0b676 | 6000 | sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
51888ca2 SV |
6001 | if (!sg) { |
6002 | printk(KERN_WARNING "Can not alloc domain group for " | |
6003 | "node %d\n", i); | |
6004 | goto error; | |
6005 | } | |
9c1cfda2 JH |
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; | |
9c1cfda2 | 6011 | } |
5517d86b | 6012 | sg->__cpu_power = 0; |
9c1cfda2 | 6013 | sg->cpumask = nodemask; |
51888ca2 | 6014 | sg->next = sg; |
9c1cfda2 JH |
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 | ||
15f0b676 SV |
6033 | sg = kmalloc_node(sizeof(struct sched_group), |
6034 | GFP_KERNEL, i); | |
9c1cfda2 JH |
6035 | if (!sg) { |
6036 | printk(KERN_WARNING | |
6037 | "Can not alloc domain group for node %d\n", j); | |
51888ca2 | 6038 | goto error; |
9c1cfda2 | 6039 | } |
5517d86b | 6040 | sg->__cpu_power = 0; |
9c1cfda2 | 6041 | sg->cpumask = tmp; |
51888ca2 | 6042 | sg->next = prev->next; |
9c1cfda2 JH |
6043 | cpus_or(covered, covered, tmp); |
6044 | prev->next = sg; | |
6045 | prev = sg; | |
6046 | } | |
9c1cfda2 | 6047 | } |
1da177e4 LT |
6048 | #endif |
6049 | ||
6050 | /* Calculate CPU power for physical packages and nodes */ | |
5c45bf27 | 6051 | #ifdef CONFIG_SCHED_SMT |
1a20ff27 | 6052 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6053 | struct sched_domain *sd = &per_cpu(cpu_domains, i); |
6054 | ||
89c4710e | 6055 | init_sched_groups_power(i, sd); |
5c45bf27 | 6056 | } |
1da177e4 | 6057 | #endif |
1e9f28fa | 6058 | #ifdef CONFIG_SCHED_MC |
5c45bf27 | 6059 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6060 | struct sched_domain *sd = &per_cpu(core_domains, i); |
6061 | ||
89c4710e | 6062 | init_sched_groups_power(i, sd); |
5c45bf27 SS |
6063 | } |
6064 | #endif | |
1e9f28fa | 6065 | |
5c45bf27 | 6066 | for_each_cpu_mask(i, *cpu_map) { |
dd41f596 IM |
6067 | struct sched_domain *sd = &per_cpu(phys_domains, i); |
6068 | ||
89c4710e | 6069 | init_sched_groups_power(i, sd); |
1da177e4 LT |
6070 | } |
6071 | ||
9c1cfda2 | 6072 | #ifdef CONFIG_NUMA |
08069033 SS |
6073 | for (i = 0; i < MAX_NUMNODES; i++) |
6074 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 6075 | |
6711cab4 SS |
6076 | if (sd_allnodes) { |
6077 | struct sched_group *sg; | |
f712c0c7 | 6078 | |
6711cab4 | 6079 | cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg); |
f712c0c7 SS |
6080 | init_numa_sched_groups_power(sg); |
6081 | } | |
9c1cfda2 JH |
6082 | #endif |
6083 | ||
1da177e4 | 6084 | /* Attach the domains */ |
1a20ff27 | 6085 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
6086 | struct sched_domain *sd; |
6087 | #ifdef CONFIG_SCHED_SMT | |
6088 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
6089 | #elif defined(CONFIG_SCHED_MC) |
6090 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
6091 | #else |
6092 | sd = &per_cpu(phys_domains, i); | |
6093 | #endif | |
6094 | cpu_attach_domain(sd, i); | |
6095 | } | |
51888ca2 SV |
6096 | |
6097 | return 0; | |
6098 | ||
a616058b | 6099 | #ifdef CONFIG_NUMA |
51888ca2 SV |
6100 | error: |
6101 | free_sched_groups(cpu_map); | |
6102 | return -ENOMEM; | |
a616058b | 6103 | #endif |
1da177e4 | 6104 | } |
1a20ff27 DG |
6105 | /* |
6106 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. | |
6107 | */ | |
51888ca2 | 6108 | static int arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
6109 | { |
6110 | cpumask_t cpu_default_map; | |
51888ca2 | 6111 | int err; |
1da177e4 | 6112 | |
1a20ff27 DG |
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 | ||
51888ca2 SV |
6120 | err = build_sched_domains(&cpu_default_map); |
6121 | ||
6122 | return err; | |
1a20ff27 DG |
6123 | } |
6124 | ||
6125 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 6126 | { |
51888ca2 | 6127 | free_sched_groups(cpu_map); |
9c1cfda2 | 6128 | } |
1da177e4 | 6129 | |
1a20ff27 DG |
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 | */ | |
858119e1 | 6134 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
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 | */ | |
51888ca2 | 6152 | int partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) |
1a20ff27 DG |
6153 | { |
6154 | cpumask_t change_map; | |
51888ca2 | 6155 | int err = 0; |
1a20ff27 DG |
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)) | |
51888ca2 SV |
6164 | err = build_sched_domains(partition1); |
6165 | if (!err && !cpus_empty(*partition2)) | |
6166 | err = build_sched_domains(partition2); | |
6167 | ||
6168 | return err; | |
1a20ff27 DG |
6169 | } |
6170 | ||
5c45bf27 SS |
6171 | #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
6172 | int arch_reinit_sched_domains(void) | |
6173 | { | |
6174 | int err; | |
6175 | ||
5be9361c | 6176 | mutex_lock(&sched_hotcpu_mutex); |
5c45bf27 SS |
6177 | detach_destroy_domains(&cpu_online_map); |
6178 | err = arch_init_sched_domains(&cpu_online_map); | |
5be9361c | 6179 | mutex_unlock(&sched_hotcpu_mutex); |
5c45bf27 SS |
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; | |
48f24c4d | 6204 | |
5c45bf27 SS |
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 | } | |
48f24c4d IM |
6224 | static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
6225 | const char *buf, size_t count) | |
5c45bf27 SS |
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 | } | |
48f24c4d IM |
6238 | static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
6239 | const char *buf, size_t count) | |
5c45bf27 SS |
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 | ||
1da177e4 LT |
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 | |
41c7ce9a | 6250 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
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 | { | |
1da177e4 LT |
6256 | switch (action) { |
6257 | case CPU_UP_PREPARE: | |
8bb78442 | 6258 | case CPU_UP_PREPARE_FROZEN: |
1da177e4 | 6259 | case CPU_DOWN_PREPARE: |
8bb78442 | 6260 | case CPU_DOWN_PREPARE_FROZEN: |
1a20ff27 | 6261 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6262 | return NOTIFY_OK; |
6263 | ||
6264 | case CPU_UP_CANCELED: | |
8bb78442 | 6265 | case CPU_UP_CANCELED_FROZEN: |
1da177e4 | 6266 | case CPU_DOWN_FAILED: |
8bb78442 | 6267 | case CPU_DOWN_FAILED_FROZEN: |
1da177e4 | 6268 | case CPU_ONLINE: |
8bb78442 | 6269 | case CPU_ONLINE_FROZEN: |
1da177e4 | 6270 | case CPU_DEAD: |
8bb78442 | 6271 | case CPU_DEAD_FROZEN: |
1da177e4 LT |
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 */ | |
1a20ff27 | 6281 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6282 | |
6283 | return NOTIFY_OK; | |
6284 | } | |
1da177e4 LT |
6285 | |
6286 | void __init sched_init_smp(void) | |
6287 | { | |
5c1e1767 NP |
6288 | cpumask_t non_isolated_cpus; |
6289 | ||
5be9361c | 6290 | mutex_lock(&sched_hotcpu_mutex); |
1a20ff27 | 6291 | arch_init_sched_domains(&cpu_online_map); |
e5e5673f | 6292 | cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
5c1e1767 NP |
6293 | if (cpus_empty(non_isolated_cpus)) |
6294 | cpu_set(smp_processor_id(), non_isolated_cpus); | |
5be9361c | 6295 | mutex_unlock(&sched_hotcpu_mutex); |
1da177e4 LT |
6296 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
6297 | hotcpu_notifier(update_sched_domains, 0); | |
5c1e1767 NP |
6298 | |
6299 | /* Move init over to a non-isolated CPU */ | |
6300 | if (set_cpus_allowed(current, non_isolated_cpus) < 0) | |
6301 | BUG(); | |
dd41f596 | 6302 | sched_init_granularity(); |
1da177e4 LT |
6303 | } |
6304 | #else | |
6305 | void __init sched_init_smp(void) | |
6306 | { | |
dd41f596 | 6307 | sched_init_granularity(); |
1da177e4 LT |
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[]; | |
48f24c4d | 6315 | |
1da177e4 LT |
6316 | return in_lock_functions(addr) || |
6317 | (addr >= (unsigned long)__sched_text_start | |
6318 | && addr < (unsigned long)__sched_text_end); | |
6319 | } | |
6320 | ||
dd41f596 IM |
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 | ||
1da177e4 LT |
6330 | void __init sched_init(void) |
6331 | { | |
dd41f596 | 6332 | u64 now = sched_clock(); |
476f3534 | 6333 | int highest_cpu = 0; |
dd41f596 IM |
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; | |
1da177e4 | 6342 | |
0a945022 | 6343 | for_each_possible_cpu(i) { |
dd41f596 | 6344 | struct rt_prio_array *array; |
70b97a7f | 6345 | struct rq *rq; |
1da177e4 LT |
6346 | |
6347 | rq = cpu_rq(i); | |
6348 | spin_lock_init(&rq->lock); | |
fcb99371 | 6349 | lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
7897986b | 6350 | rq->nr_running = 0; |
dd41f596 IM |
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; | |
1da177e4 | 6359 | |
dd41f596 IM |
6360 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6361 | rq->cpu_load[j] = 0; | |
1da177e4 | 6362 | #ifdef CONFIG_SMP |
41c7ce9a | 6363 | rq->sd = NULL; |
1da177e4 | 6364 | rq->active_balance = 0; |
dd41f596 | 6365 | rq->next_balance = jiffies; |
1da177e4 | 6366 | rq->push_cpu = 0; |
0a2966b4 | 6367 | rq->cpu = i; |
1da177e4 LT |
6368 | rq->migration_thread = NULL; |
6369 | INIT_LIST_HEAD(&rq->migration_queue); | |
6370 | #endif | |
6371 | atomic_set(&rq->nr_iowait, 0); | |
6372 | ||
dd41f596 IM |
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); | |
1da177e4 | 6377 | } |
476f3534 | 6378 | highest_cpu = i; |
dd41f596 IM |
6379 | /* delimiter for bitsearch: */ |
6380 | __set_bit(MAX_RT_PRIO, array->bitmap); | |
1da177e4 LT |
6381 | } |
6382 | ||
2dd73a4f | 6383 | set_load_weight(&init_task); |
b50f60ce | 6384 | |
c9819f45 | 6385 | #ifdef CONFIG_SMP |
476f3534 | 6386 | nr_cpu_ids = highest_cpu + 1; |
c9819f45 CL |
6387 | open_softirq(SCHED_SOFTIRQ, run_rebalance_domains, NULL); |
6388 | #endif | |
6389 | ||
b50f60ce HC |
6390 | #ifdef CONFIG_RT_MUTEXES |
6391 | plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); | |
6392 | #endif | |
6393 | ||
1da177e4 LT |
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()); | |
dd41f596 IM |
6407 | /* |
6408 | * During early bootup we pretend to be a normal task: | |
6409 | */ | |
6410 | current->sched_class = &fair_sched_class; | |
1da177e4 LT |
6411 | } |
6412 | ||
6413 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6414 | void __might_sleep(char *file, int line) | |
6415 | { | |
48f24c4d | 6416 | #ifdef in_atomic |
1da177e4 LT |
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; | |
91368d73 | 6424 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6425 | " context at %s:%d\n", file, line); |
6426 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6427 | in_atomic(), irqs_disabled()); | |
a4c410f0 | 6428 | debug_show_held_locks(current); |
3117df04 IM |
6429 | if (irqs_disabled()) |
6430 | print_irqtrace_events(current); | |
1da177e4 LT |
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 | { | |
a0f98a1c | 6441 | struct task_struct *g, *p; |
1da177e4 | 6442 | unsigned long flags; |
70b97a7f | 6443 | struct rq *rq; |
dd41f596 | 6444 | int on_rq; |
1da177e4 LT |
6445 | |
6446 | read_lock_irq(&tasklist_lock); | |
a0f98a1c | 6447 | do_each_thread(g, p) { |
dd41f596 IM |
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); | |
1da177e4 | 6466 | continue; |
dd41f596 | 6467 | } |
1da177e4 | 6468 | |
b29739f9 IM |
6469 | spin_lock_irqsave(&p->pi_lock, flags); |
6470 | rq = __task_rq_lock(p); | |
dd41f596 IM |
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 | |
1da177e4 | 6478 | |
dd41f596 IM |
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); | |
1da177e4 LT |
6485 | resched_task(rq->curr); |
6486 | } | |
dd41f596 IM |
6487 | #ifdef CONFIG_SMP |
6488 | out_unlock: | |
6489 | #endif | |
b29739f9 IM |
6490 | __task_rq_unlock(rq); |
6491 | spin_unlock_irqrestore(&p->pi_lock, flags); | |
a0f98a1c IM |
6492 | } while_each_thread(g, p); |
6493 | ||
1da177e4 LT |
6494 | read_unlock_irq(&tasklist_lock); |
6495 | } | |
6496 | ||
6497 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
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 | */ | |
36c8b586 | 6516 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
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 | */ | |
36c8b586 | 6536 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6537 | { |
6538 | cpu_curr(cpu) = p; | |
6539 | } | |
6540 | ||
6541 | #endif |