Contents of /alx-src/tags/kernel26-2.6.12-alx-r9/kernel/sched.c.orig
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Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File size: 122911 byte(s)
Wed Mar 4 11:03:09 2009 UTC (15 years, 3 months ago) by niro
File size: 122911 byte(s)
Tag kernel26-2.6.12-alx-r9
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 | * 2005-06-07 New staircase scheduling policy by Con Kolivas with help |
20 | * from William Lee Irwin III, Zwane Mwaikambo & Peter Williams. |
21 | * Staircase v11.3 |
22 | */ |
23 | |
24 | #include <linux/mm.h> |
25 | #include <linux/module.h> |
26 | #include <linux/nmi.h> |
27 | #include <linux/init.h> |
28 | #include <asm/uaccess.h> |
29 | #include <linux/highmem.h> |
30 | #include <linux/smp_lock.h> |
31 | #include <asm/mmu_context.h> |
32 | #include <linux/interrupt.h> |
33 | #include <linux/completion.h> |
34 | #include <linux/kernel_stat.h> |
35 | #include <linux/security.h> |
36 | #include <linux/notifier.h> |
37 | #include <linux/profile.h> |
38 | #include <linux/suspend.h> |
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> |
52 | #include <linux/acct.h> |
53 | #include <asm/tlb.h> |
54 | |
55 | #include <asm/unistd.h> |
56 | |
57 | /* |
58 | * Convert user-nice values [ -20 ... 0 ... 19 ] |
59 | * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], |
60 | * and back. |
61 | */ |
62 | #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) |
63 | #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) |
64 | #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) |
65 | |
66 | /* |
67 | * 'User priority' is the nice value converted to something we |
68 | * can work with better when scaling various scheduler parameters, |
69 | * it's a [ 0 ... 39 ] range. |
70 | */ |
71 | #define USER_PRIO(p) ((p)-MAX_RT_PRIO) |
72 | #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) |
73 | #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) |
74 | |
75 | /* |
76 | * Some helpers for converting nanosecond timing to jiffy resolution |
77 | */ |
78 | #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) |
79 | #define NSJIFFY (1000000000 / HZ) /* One jiffy in ns */ |
80 | |
81 | int sched_compute = 0; |
82 | /* |
83 | *This is the time all tasks within the same priority round robin. |
84 | *compute setting is reserved for dedicated computational scheduling |
85 | *and has ten times larger intervals. |
86 | */ |
87 | #define _RR_INTERVAL ((10 * HZ / 1000) ? : 1) |
88 | #define RR_INTERVAL() (_RR_INTERVAL * (1 + 9 * sched_compute)) |
89 | #define DEF_TIMESLICE (RR_INTERVAL() * 19) |
90 | |
91 | #define task_hot(p, now, sd) ((long long) ((now) - (p)->timestamp) \ |
92 | < (long long) (sd)->cache_hot_time) |
93 | |
94 | /* |
95 | * These are the runqueue data structures: |
96 | */ |
97 | |
98 | typedef struct runqueue runqueue_t; |
99 | |
100 | /* |
101 | * This is the main, per-CPU runqueue data structure. |
102 | * |
103 | * Locking rule: those places that want to lock multiple runqueues |
104 | * (such as the load balancing or the thread migration code), lock |
105 | * acquire operations must be ordered by ascending &runqueue. |
106 | */ |
107 | struct runqueue { |
108 | spinlock_t lock; |
109 | |
110 | /* |
111 | * nr_running and cpu_load should be in the same cacheline because |
112 | * remote CPUs use both these fields when doing load calculation. |
113 | */ |
114 | unsigned long nr_running; |
115 | #ifdef CONFIG_SMP |
116 | unsigned long prio_bias; |
117 | unsigned long cpu_load; |
118 | #endif |
119 | unsigned long long nr_switches; |
120 | |
121 | /* |
122 | * This is part of a global counter where only the total sum |
123 | * over all CPUs matters. A task can increase this counter on |
124 | * one CPU and if it got migrated afterwards it may decrease |
125 | * it on another CPU. Always updated under the runqueue lock: |
126 | */ |
127 | unsigned long nr_uninterruptible; |
128 | |
129 | unsigned long long timestamp_last_tick; |
130 | unsigned int cache_ticks, preempted; |
131 | task_t *curr, *idle; |
132 | struct mm_struct *prev_mm; |
133 | unsigned long bitmap[BITS_TO_LONGS(MAX_PRIO + 1)]; |
134 | struct list_head queue[MAX_PRIO]; |
135 | atomic_t nr_iowait; |
136 | |
137 | #ifdef CONFIG_SMP |
138 | struct sched_domain *sd; |
139 | |
140 | /* For active balancing */ |
141 | int active_balance; |
142 | int push_cpu; |
143 | |
144 | task_t *migration_thread; |
145 | struct list_head migration_queue; |
146 | #endif |
147 | |
148 | #ifdef CONFIG_SCHEDSTATS |
149 | /* latency stats */ |
150 | struct sched_info rq_sched_info; |
151 | |
152 | /* sys_sched_yield() stats */ |
153 | unsigned long yld_exp_empty; |
154 | unsigned long yld_act_empty; |
155 | unsigned long yld_both_empty; |
156 | unsigned long yld_cnt; |
157 | |
158 | /* schedule() stats */ |
159 | unsigned long sched_switch; |
160 | unsigned long sched_cnt; |
161 | unsigned long sched_goidle; |
162 | |
163 | /* try_to_wake_up() stats */ |
164 | unsigned long ttwu_cnt; |
165 | unsigned long ttwu_local; |
166 | #endif |
167 | }; |
168 | |
169 | static DEFINE_PER_CPU(struct runqueue, runqueues); |
170 | |
171 | #define for_each_domain(cpu, domain) \ |
172 | for (domain = cpu_rq(cpu)->sd; domain; domain = domain->parent) |
173 | |
174 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) |
175 | #define this_rq() (&__get_cpu_var(runqueues)) |
176 | #define task_rq(p) cpu_rq(task_cpu(p)) |
177 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) |
178 | |
179 | /* |
180 | * Default context-switch locking: |
181 | */ |
182 | #ifndef prepare_arch_switch |
183 | # define prepare_arch_switch(rq, next) do { } while (0) |
184 | # define finish_arch_switch(rq, next) spin_unlock_irq(&(rq)->lock) |
185 | # define task_running(rq, p) ((rq)->curr == (p)) |
186 | #endif |
187 | |
188 | /* |
189 | * task_rq_lock - lock the runqueue a given task resides on and disable |
190 | * interrupts. Note the ordering: we can safely lookup the task_rq without |
191 | * explicitly disabling preemption. |
192 | */ |
193 | static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags) |
194 | __acquires(rq->lock) |
195 | { |
196 | struct runqueue *rq; |
197 | |
198 | repeat_lock_task: |
199 | local_irq_save(*flags); |
200 | rq = task_rq(p); |
201 | spin_lock(&rq->lock); |
202 | if (unlikely(rq != task_rq(p))) { |
203 | spin_unlock_irqrestore(&rq->lock, *flags); |
204 | goto repeat_lock_task; |
205 | } |
206 | return rq; |
207 | } |
208 | |
209 | static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags) |
210 | __releases(rq->lock) |
211 | { |
212 | spin_unlock_irqrestore(&rq->lock, *flags); |
213 | } |
214 | |
215 | #ifdef CONFIG_SCHEDSTATS |
216 | /* |
217 | * bump this up when changing the output format or the meaning of an existing |
218 | * format, so that tools can adapt (or abort) |
219 | */ |
220 | #define SCHEDSTAT_VERSION 11 |
221 | |
222 | static int show_schedstat(struct seq_file *seq, void *v) |
223 | { |
224 | int cpu; |
225 | |
226 | seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); |
227 | seq_printf(seq, "timestamp %lu\n", jiffies); |
228 | for_each_online_cpu(cpu) { |
229 | runqueue_t *rq = cpu_rq(cpu); |
230 | #ifdef CONFIG_SMP |
231 | struct sched_domain *sd; |
232 | int dcnt = 0; |
233 | #endif |
234 | |
235 | /* runqueue-specific stats */ |
236 | seq_printf(seq, |
237 | "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu", |
238 | cpu, rq->yld_both_empty, |
239 | rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt, |
240 | rq->sched_switch, rq->sched_cnt, rq->sched_goidle, |
241 | rq->ttwu_cnt, rq->ttwu_local, |
242 | rq->rq_sched_info.cpu_time, |
243 | rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt); |
244 | |
245 | seq_printf(seq, "\n"); |
246 | |
247 | #ifdef CONFIG_SMP |
248 | /* domain-specific stats */ |
249 | for_each_domain(cpu, sd) { |
250 | enum idle_type itype; |
251 | char mask_str[NR_CPUS]; |
252 | |
253 | cpumask_scnprintf(mask_str, NR_CPUS, sd->span); |
254 | seq_printf(seq, "domain%d %s", dcnt++, mask_str); |
255 | for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; |
256 | itype++) { |
257 | seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu", |
258 | sd->lb_cnt[itype], |
259 | sd->lb_balanced[itype], |
260 | sd->lb_failed[itype], |
261 | sd->lb_imbalance[itype], |
262 | sd->lb_gained[itype], |
263 | sd->lb_hot_gained[itype], |
264 | sd->lb_nobusyq[itype], |
265 | sd->lb_nobusyg[itype]); |
266 | } |
267 | seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu\n", |
268 | sd->alb_cnt, sd->alb_failed, sd->alb_pushed, |
269 | sd->sbe_pushed, sd->sbe_attempts, |
270 | sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance); |
271 | } |
272 | #endif |
273 | } |
274 | return 0; |
275 | } |
276 | |
277 | static int schedstat_open(struct inode *inode, struct file *file) |
278 | { |
279 | unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32); |
280 | char *buf = kmalloc(size, GFP_KERNEL); |
281 | struct seq_file *m; |
282 | int res; |
283 | |
284 | if (!buf) |
285 | return -ENOMEM; |
286 | res = single_open(file, show_schedstat, NULL); |
287 | if (!res) { |
288 | m = file->private_data; |
289 | m->buf = buf; |
290 | m->size = size; |
291 | } else |
292 | kfree(buf); |
293 | return res; |
294 | } |
295 | |
296 | struct file_operations proc_schedstat_operations = { |
297 | .open = schedstat_open, |
298 | .read = seq_read, |
299 | .llseek = seq_lseek, |
300 | .release = single_release, |
301 | }; |
302 | |
303 | # define schedstat_inc(rq, field) do { (rq)->field++; } while (0) |
304 | # define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0) |
305 | #else /* !CONFIG_SCHEDSTATS */ |
306 | # define schedstat_inc(rq, field) do { } while (0) |
307 | # define schedstat_add(rq, field, amt) do { } while (0) |
308 | #endif |
309 | |
310 | /* |
311 | * rq_lock - lock a given runqueue and disable interrupts. |
312 | */ |
313 | static inline runqueue_t *this_rq_lock(void) |
314 | __acquires(rq->lock) |
315 | { |
316 | runqueue_t *rq; |
317 | |
318 | local_irq_disable(); |
319 | rq = this_rq(); |
320 | spin_lock(&rq->lock); |
321 | |
322 | return rq; |
323 | } |
324 | |
325 | #ifdef CONFIG_SCHED_SMT |
326 | static int cpu_and_siblings_are_idle(int cpu) |
327 | { |
328 | int sib; |
329 | for_each_cpu_mask(sib, cpu_sibling_map[cpu]) { |
330 | if (idle_cpu(sib)) |
331 | continue; |
332 | return 0; |
333 | } |
334 | |
335 | return 1; |
336 | } |
337 | #else |
338 | #define cpu_and_siblings_are_idle(A) idle_cpu(A) |
339 | #endif |
340 | |
341 | #ifdef CONFIG_SCHEDSTATS |
342 | /* |
343 | * Called when a process is dequeued from the active array and given |
344 | * the cpu. We should note that with the exception of interactive |
345 | * tasks, the expired queue will become the active queue after the active |
346 | * queue is empty, without explicitly dequeuing and requeuing tasks in the |
347 | * expired queue. (Interactive tasks may be requeued directly to the |
348 | * active queue, thus delaying tasks in the expired queue from running; |
349 | * see scheduler_tick()). |
350 | * |
351 | * This function is only called from sched_info_arrive(), rather than |
352 | * dequeue_task(). Even though a task may be queued and dequeued multiple |
353 | * times as it is shuffled about, we're really interested in knowing how |
354 | * long it was from the *first* time it was queued to the time that it |
355 | * finally hit a cpu. |
356 | */ |
357 | static inline void sched_info_dequeued(task_t *t) |
358 | { |
359 | t->sched_info.last_queued = 0; |
360 | } |
361 | |
362 | /* |
363 | * Called when a task finally hits the cpu. We can now calculate how |
364 | * long it was waiting to run. We also note when it began so that we |
365 | * can keep stats on how long its timeslice is. |
366 | */ |
367 | static inline void sched_info_arrive(task_t *t) |
368 | { |
369 | unsigned long now = jiffies, diff = 0; |
370 | struct runqueue *rq = task_rq(t); |
371 | |
372 | if (t->sched_info.last_queued) |
373 | diff = now - t->sched_info.last_queued; |
374 | sched_info_dequeued(t); |
375 | t->sched_info.run_delay += diff; |
376 | t->sched_info.last_arrival = now; |
377 | t->sched_info.pcnt++; |
378 | |
379 | if (!rq) |
380 | return; |
381 | |
382 | rq->rq_sched_info.run_delay += diff; |
383 | rq->rq_sched_info.pcnt++; |
384 | } |
385 | |
386 | /* |
387 | * Called when a process is queued into either the active or expired |
388 | * array. The time is noted and later used to determine how long we |
389 | * had to wait for us to reach the cpu. Since the expired queue will |
390 | * become the active queue after active queue is empty, without dequeuing |
391 | * and requeuing any tasks, we are interested in queuing to either. It |
392 | * is unusual but not impossible for tasks to be dequeued and immediately |
393 | * requeued in the same or another array: this can happen in sched_yield(), |
394 | * set_user_nice(), and even load_balance() as it moves tasks from runqueue |
395 | * to runqueue. |
396 | * |
397 | * This function is only called from enqueue_task(), but also only updates |
398 | * the timestamp if it is already not set. It's assumed that |
399 | * sched_info_dequeued() will clear that stamp when appropriate. |
400 | */ |
401 | static inline void sched_info_queued(task_t *t) |
402 | { |
403 | if (!t->sched_info.last_queued) |
404 | t->sched_info.last_queued = jiffies; |
405 | } |
406 | |
407 | /* |
408 | * Called when a process ceases being the active-running process, either |
409 | * voluntarily or involuntarily. Now we can calculate how long we ran. |
410 | */ |
411 | static inline void sched_info_depart(task_t *t) |
412 | { |
413 | struct runqueue *rq = task_rq(t); |
414 | unsigned long diff = jiffies - t->sched_info.last_arrival; |
415 | |
416 | t->sched_info.cpu_time += diff; |
417 | |
418 | if (rq) |
419 | rq->rq_sched_info.cpu_time += diff; |
420 | } |
421 | |
422 | /* |
423 | * Called when tasks are switched involuntarily due, typically, to expiring |
424 | * their time slice. (This may also be called when switching to or from |
425 | * the idle task.) We are only called when prev != next. |
426 | */ |
427 | static inline void sched_info_switch(task_t *prev, task_t *next) |
428 | { |
429 | struct runqueue *rq = task_rq(prev); |
430 | |
431 | /* |
432 | * prev now departs the cpu. It's not interesting to record |
433 | * stats about how efficient we were at scheduling the idle |
434 | * process, however. |
435 | */ |
436 | if (prev != rq->idle) |
437 | sched_info_depart(prev); |
438 | |
439 | if (next != rq->idle) |
440 | sched_info_arrive(next); |
441 | } |
442 | #else |
443 | #define sched_info_queued(t) do { } while (0) |
444 | #define sched_info_switch(t, next) do { } while (0) |
445 | #endif /* CONFIG_SCHEDSTATS */ |
446 | |
447 | /* |
448 | * Get nanosecond clock difference without overflowing unsigned long. |
449 | */ |
450 | static inline unsigned long ns_diff(unsigned long long v1, unsigned long long v2) |
451 | { |
452 | unsigned long long vdiff; |
453 | if (likely(v1 > v2)) { |
454 | vdiff = v1 - v2; |
455 | if (vdiff > (1 << 31)) |
456 | vdiff = 1 << 31; |
457 | } else |
458 | /* |
459 | * Rarely the clock appears to go backwards. There should |
460 | * always be a positive difference so return 1. |
461 | */ |
462 | vdiff = 1; |
463 | return (unsigned long)vdiff; |
464 | } |
465 | |
466 | static inline int task_queued(task_t *task) |
467 | { |
468 | return !list_empty(&task->run_list); |
469 | } |
470 | |
471 | /* |
472 | * Adding/removing a task to/from a runqueue: |
473 | */ |
474 | static inline void dequeue_task(struct task_struct *p, runqueue_t *rq) |
475 | { |
476 | list_del_init(&p->run_list); |
477 | if (list_empty(rq->queue + p->prio)) |
478 | __clear_bit(p->prio, rq->bitmap); |
479 | p->ns_debit = 0; |
480 | } |
481 | |
482 | static void enqueue_task(struct task_struct *p, runqueue_t *rq) |
483 | { |
484 | list_add_tail(&p->run_list, rq->queue + p->prio); |
485 | __set_bit(p->prio, rq->bitmap); |
486 | } |
487 | |
488 | /* |
489 | * Put task to the end of the run list without the overhead of dequeue |
490 | * followed by enqueue. |
491 | */ |
492 | static inline void requeue_task(struct task_struct *p, runqueue_t *rq) |
493 | { |
494 | list_move_tail(&p->run_list, rq->queue + p->prio); |
495 | } |
496 | |
497 | static inline void enqueue_task_head(struct task_struct *p, runqueue_t *rq) |
498 | { |
499 | list_add(&p->run_list, rq->queue + p->prio); |
500 | __set_bit(p->prio, rq->bitmap); |
501 | } |
502 | |
503 | #ifdef CONFIG_SMP |
504 | static inline void inc_prio_bias(runqueue_t *rq, int prio) |
505 | { |
506 | rq->prio_bias += MAX_PRIO - prio; |
507 | } |
508 | |
509 | static inline void dec_prio_bias(runqueue_t *rq, int prio) |
510 | { |
511 | rq->prio_bias -= MAX_PRIO - prio; |
512 | } |
513 | #else |
514 | static inline void inc_prio_bias(runqueue_t *rq, int prio) |
515 | { |
516 | } |
517 | |
518 | static inline void dec_prio_bias(runqueue_t *rq, int prio) |
519 | { |
520 | } |
521 | #endif |
522 | |
523 | static inline void inc_nr_running(task_t *p, runqueue_t *rq) |
524 | { |
525 | rq->nr_running++; |
526 | if (rt_task(p)) { |
527 | if (p != rq->migration_thread) |
528 | inc_prio_bias(rq, p->prio); |
529 | } else |
530 | inc_prio_bias(rq, p->static_prio); |
531 | } |
532 | |
533 | static inline void dec_nr_running(task_t *p, runqueue_t *rq) |
534 | { |
535 | rq->nr_running--; |
536 | if (rt_task(p)) { |
537 | if (p != rq->migration_thread) |
538 | dec_prio_bias(rq, p->prio); |
539 | } else |
540 | dec_prio_bias(rq, p->static_prio); |
541 | } |
542 | |
543 | /* |
544 | * __activate_task - move a task to the runqueue. |
545 | */ |
546 | static void __activate_task(task_t *p, runqueue_t *rq) |
547 | { |
548 | enqueue_task(p, rq); |
549 | inc_nr_running(p, rq); |
550 | } |
551 | |
552 | /* |
553 | * __activate_idle_task - move idle task to the _front_ of runqueue. |
554 | */ |
555 | static inline void __activate_idle_task(task_t *p, runqueue_t *rq) |
556 | { |
557 | enqueue_task_head(p, rq); |
558 | inc_nr_running(p, rq); |
559 | } |
560 | |
561 | /* |
562 | * burst - extra intervals an interactive task can run for at best priority |
563 | * instead of descending priorities. |
564 | */ |
565 | static inline unsigned int burst(task_t *p) |
566 | { |
567 | if (likely(!rt_task(p))) { |
568 | unsigned int task_user_prio = TASK_USER_PRIO(p); |
569 | return 39 - task_user_prio; |
570 | } else |
571 | return p->burst; |
572 | } |
573 | |
574 | static void inc_burst(task_t *p) |
575 | { |
576 | unsigned int best_burst; |
577 | best_burst = burst(p); |
578 | if (p->burst < best_burst) |
579 | p->burst++; |
580 | } |
581 | |
582 | static void dec_burst(task_t *p) |
583 | { |
584 | if (p->burst) |
585 | p->burst--; |
586 | } |
587 | |
588 | static inline unsigned int rr_interval(task_t * p) |
589 | { |
590 | unsigned int rr_interval = RR_INTERVAL(); |
591 | int nice = TASK_NICE(p); |
592 | |
593 | if (nice < 0 && !rt_task(p)) |
594 | rr_interval += -(nice); |
595 | return rr_interval; |
596 | } |
597 | |
598 | /* |
599 | * slice - the duration a task runs before getting requeued at its best |
600 | * priority and has its burst decremented. |
601 | */ |
602 | static inline unsigned int slice(task_t *p) |
603 | { |
604 | unsigned int slice, rr; |
605 | slice = rr = rr_interval(p); |
606 | if (likely(!rt_task(p))) |
607 | slice += burst(p) * rr; |
608 | return slice; |
609 | } |
610 | |
611 | /* |
612 | * sched_interactive - sysctl which allows interactive tasks to have bursts |
613 | */ |
614 | int sched_interactive = 1; |
615 | |
616 | /* |
617 | * effective_prio - dynamic priority dependent on burst. |
618 | * The priority normally decreases by one each RR_INTERVAL. |
619 | * As the burst increases the priority stays at the top "stair" or |
620 | * priority for longer. |
621 | */ |
622 | static int effective_prio(task_t *p) |
623 | { |
624 | int prio; |
625 | unsigned int full_slice, used_slice, first_slice; |
626 | unsigned int best_burst, rr; |
627 | if (rt_task(p)) |
628 | return p->prio; |
629 | if (batch_task(p)) { |
630 | if (unlikely(p->flags & (PF_NONSLEEP | PF_FREEZE))) { |
631 | /* |
632 | * If batch is waking up from in kernel activity |
633 | * or being frozen, reschedule at a normal priority |
634 | * to begin with. |
635 | */ |
636 | p->flags |= PF_YIELDED; |
637 | return MAX_PRIO - 2; |
638 | } |
639 | return MAX_PRIO - 1; |
640 | } |
641 | |
642 | best_burst = burst(p); |
643 | full_slice = slice(p); |
644 | rr = rr_interval(p); |
645 | used_slice = full_slice - p->slice; |
646 | if (p->burst > best_burst) |
647 | p->burst = best_burst; |
648 | first_slice = rr; |
649 | if (sched_interactive && !sched_compute && p->mm) |
650 | first_slice *= (p->burst + 1); |
651 | prio = MAX_PRIO - 2 - best_burst; |
652 | |
653 | if (used_slice < first_slice) |
654 | return prio; |
655 | prio += 1 + (used_slice - first_slice) / rr; |
656 | if (prio >= MAX_PRIO - 2) |
657 | prio = MAX_PRIO - 2; |
658 | return prio; |
659 | } |
660 | |
661 | static void continue_slice(task_t *p) |
662 | { |
663 | unsigned long total_run = NS_TO_JIFFIES(p->totalrun); |
664 | |
665 | if (total_run >= p->slice) { |
666 | p->totalrun = 0; |
667 | dec_burst(p); |
668 | } else { |
669 | unsigned int remainder; |
670 | p->slice -= total_run; |
671 | remainder = p->slice % rr_interval(p); |
672 | if (remainder) |
673 | p->time_slice = remainder; |
674 | } |
675 | } |
676 | |
677 | /* |
678 | * recalc_task_prio - this checks for tasks that run ultra short timeslices |
679 | * or have just forked a thread/process and make them continue their old |
680 | * slice instead of starting a new one at high priority. |
681 | */ |
682 | static inline void recalc_task_prio(task_t *p, unsigned long long now, |
683 | unsigned long rq_running) |
684 | { |
685 | unsigned long sleep_time = ns_diff(now, p->timestamp); |
686 | |
687 | /* |
688 | * Priority is elevated back to best by amount of sleep_time. |
689 | * sleep_time is scaled down by number of tasks currently running. |
690 | */ |
691 | if (rq_running > 1) |
692 | sleep_time /= rq_running; |
693 | |
694 | p->totalrun += p->runtime; |
695 | if (NS_TO_JIFFIES(p->totalrun) >= p->slice && |
696 | NS_TO_JIFFIES(sleep_time) < p->slice) { |
697 | p->flags &= ~PF_NONSLEEP; |
698 | dec_burst(p); |
699 | goto new_slice; |
700 | } |
701 | |
702 | if (p->flags & PF_NONSLEEP) { |
703 | continue_slice(p); |
704 | p->flags &= ~PF_NONSLEEP; |
705 | goto out; |
706 | } |
707 | |
708 | if (sched_compute) { |
709 | continue_slice(p); |
710 | goto out; |
711 | } |
712 | |
713 | if (sleep_time >= p->totalrun) { |
714 | if (!(p->flags & PF_NONSLEEP)) |
715 | inc_burst(p); |
716 | goto new_slice; |
717 | } |
718 | |
719 | p->totalrun -= sleep_time; |
720 | continue_slice(p); |
721 | goto out; |
722 | new_slice: |
723 | p->totalrun = 0; |
724 | out: |
725 | return; |
726 | } |
727 | |
728 | /* |
729 | * activate_task - move a task to the runqueue and do priority recalculation |
730 | * |
731 | * Update all the scheduling statistics stuff. (sleep average |
732 | * calculation, priority modifiers, etc.) |
733 | */ |
734 | static void activate_task(task_t *p, runqueue_t *rq, int local) |
735 | { |
736 | unsigned long long now = sched_clock(); |
737 | #ifdef CONFIG_SMP |
738 | if (!local) { |
739 | /* Compensate for drifting sched_clock */ |
740 | runqueue_t *this_rq = this_rq(); |
741 | now = (now - this_rq->timestamp_last_tick) |
742 | + rq->timestamp_last_tick; |
743 | } |
744 | #endif |
745 | p->slice = slice(p); |
746 | p->time_slice = rr_interval(p); |
747 | recalc_task_prio(p, now, rq->nr_running); |
748 | p->flags &= ~PF_NONSLEEP; |
749 | p->prio = effective_prio(p); |
750 | p->timestamp = now; |
751 | __activate_task(p, rq); |
752 | } |
753 | |
754 | /* |
755 | * deactivate_task - remove a task from the runqueue. |
756 | */ |
757 | static inline void deactivate_task(struct task_struct *p, runqueue_t *rq) |
758 | { |
759 | dec_nr_running(p, rq); |
760 | dequeue_task(p, rq); |
761 | } |
762 | |
763 | /* |
764 | * resched_task - mark a task 'to be rescheduled now'. |
765 | * |
766 | * On UP this means the setting of the need_resched flag, on SMP it |
767 | * might also involve a cross-CPU call to trigger the scheduler on |
768 | * the target CPU. |
769 | */ |
770 | #ifdef CONFIG_SMP |
771 | static void resched_task(task_t *p) |
772 | { |
773 | int need_resched, nrpolling; |
774 | |
775 | assert_spin_locked(&task_rq(p)->lock); |
776 | |
777 | /* minimise the chance of sending an interrupt to poll_idle() */ |
778 | nrpolling = test_tsk_thread_flag(p,TIF_POLLING_NRFLAG); |
779 | need_resched = test_and_set_tsk_thread_flag(p,TIF_NEED_RESCHED); |
780 | nrpolling |= test_tsk_thread_flag(p,TIF_POLLING_NRFLAG); |
781 | |
782 | if (!need_resched && !nrpolling && (task_cpu(p) != smp_processor_id())) |
783 | smp_send_reschedule(task_cpu(p)); |
784 | } |
785 | #else |
786 | static inline void resched_task(task_t *p) |
787 | { |
788 | set_tsk_need_resched(p); |
789 | } |
790 | #endif |
791 | |
792 | /** |
793 | * task_curr - is this task currently executing on a CPU? |
794 | * @p: the task in question. |
795 | */ |
796 | inline int task_curr(const task_t *p) |
797 | { |
798 | return cpu_curr(task_cpu(p)) == p; |
799 | } |
800 | |
801 | #ifdef CONFIG_SMP |
802 | enum request_type { |
803 | REQ_MOVE_TASK, |
804 | REQ_SET_DOMAIN, |
805 | }; |
806 | |
807 | typedef struct { |
808 | struct list_head list; |
809 | enum request_type type; |
810 | |
811 | /* For REQ_MOVE_TASK */ |
812 | task_t *task; |
813 | int dest_cpu; |
814 | |
815 | /* For REQ_SET_DOMAIN */ |
816 | struct sched_domain *sd; |
817 | |
818 | struct completion done; |
819 | } migration_req_t; |
820 | |
821 | /* |
822 | * The task's runqueue lock must be held. |
823 | * Returns true if you have to wait for migration thread. |
824 | */ |
825 | static int migrate_task(task_t *p, int dest_cpu, migration_req_t *req) |
826 | { |
827 | runqueue_t *rq = task_rq(p); |
828 | |
829 | /* |
830 | * If the task is not on a runqueue (and not running), then |
831 | * it is sufficient to simply update the task's cpu field. |
832 | */ |
833 | if (!task_queued(p) && !task_running(rq, p)) { |
834 | set_task_cpu(p, dest_cpu); |
835 | return 0; |
836 | } |
837 | |
838 | init_completion(&req->done); |
839 | req->type = REQ_MOVE_TASK; |
840 | req->task = p; |
841 | req->dest_cpu = dest_cpu; |
842 | list_add(&req->list, &rq->migration_queue); |
843 | return 1; |
844 | } |
845 | |
846 | /* |
847 | * wait_task_inactive - wait for a thread to unschedule. |
848 | * |
849 | * The caller must ensure that the task *will* unschedule sometime soon, |
850 | * else this function might spin for a *long* time. This function can't |
851 | * be called with interrupts off, or it may introduce deadlock with |
852 | * smp_call_function() if an IPI is sent by the same process we are |
853 | * waiting to become inactive. |
854 | */ |
855 | void wait_task_inactive(task_t * p) |
856 | { |
857 | unsigned long flags; |
858 | runqueue_t *rq; |
859 | int preempted; |
860 | |
861 | repeat: |
862 | rq = task_rq_lock(p, &flags); |
863 | /* Must be off runqueue entirely, not preempted. */ |
864 | if (unlikely(task_queued(p) || task_running(rq, p))) { |
865 | /* If it's preempted, we yield. It could be a while. */ |
866 | preempted = !task_running(rq, p); |
867 | task_rq_unlock(rq, &flags); |
868 | cpu_relax(); |
869 | if (preempted) |
870 | yield(); |
871 | goto repeat; |
872 | } |
873 | task_rq_unlock(rq, &flags); |
874 | } |
875 | |
876 | /*** |
877 | * kick_process - kick a running thread to enter/exit the kernel |
878 | * @p: the to-be-kicked thread |
879 | * |
880 | * Cause a process which is running on another CPU to enter |
881 | * kernel-mode, without any delay. (to get signals handled.) |
882 | * |
883 | * NOTE: this function doesnt have to take the runqueue lock, |
884 | * because all it wants to ensure is that the remote task enters |
885 | * the kernel. If the IPI races and the task has been migrated |
886 | * to another CPU then no harm is done and the purpose has been |
887 | * achieved as well. |
888 | */ |
889 | void kick_process(task_t *p) |
890 | { |
891 | int cpu; |
892 | |
893 | preempt_disable(); |
894 | cpu = task_cpu(p); |
895 | if ((cpu != smp_processor_id()) && task_curr(p)) |
896 | smp_send_reschedule(cpu); |
897 | preempt_enable(); |
898 | } |
899 | |
900 | /* |
901 | * Return a low guess at the load of a migration-source cpu. |
902 | * |
903 | * We want to under-estimate the load of migration sources, to |
904 | * balance conservatively. |
905 | */ |
906 | static inline unsigned long __source_load(int cpu, enum idle_type idle) |
907 | { |
908 | runqueue_t *rq = cpu_rq(cpu); |
909 | unsigned long source_load, cpu_load = rq->cpu_load, |
910 | load_now = rq->nr_running * SCHED_LOAD_SCALE; |
911 | |
912 | source_load = min(cpu_load, load_now); |
913 | |
914 | if (rq->nr_running > 1 || (idle == NOT_IDLE && rq->nr_running)) |
915 | /* |
916 | * If we are busy rebalancing the load is biased by |
917 | * priority to create 'nice' support across cpus. When |
918 | * idle rebalancing we should only bias the source_load if |
919 | * there is more than one task running on that queue to |
920 | * prevent idle rebalance from trying to pull tasks from a |
921 | * queue with only one running task. |
922 | */ |
923 | source_load = source_load * rq->prio_bias / rq->nr_running; |
924 | |
925 | return source_load; |
926 | } |
927 | |
928 | static inline unsigned long source_load(int cpu) |
929 | { |
930 | return __source_load(cpu, NOT_IDLE); |
931 | } |
932 | |
933 | /* |
934 | * Return a high guess at the load of a migration-target cpu |
935 | */ |
936 | static inline unsigned long __target_load(int cpu, enum idle_type idle) |
937 | { |
938 | runqueue_t *rq = cpu_rq(cpu); |
939 | unsigned long target_load, cpu_load = rq->cpu_load, |
940 | load_now = rq->nr_running * SCHED_LOAD_SCALE; |
941 | |
942 | target_load = max(cpu_load, load_now); |
943 | |
944 | if (rq->nr_running > 1 || (idle == NOT_IDLE && rq->nr_running)) |
945 | target_load = target_load * rq->prio_bias / rq->nr_running; |
946 | |
947 | return target_load; |
948 | } |
949 | |
950 | static inline unsigned long target_load(int cpu) |
951 | { |
952 | return __target_load(cpu, NOT_IDLE); |
953 | } |
954 | #endif |
955 | |
956 | /* |
957 | * wake_idle() will wake a task on an idle cpu if task->cpu is |
958 | * not idle and an idle cpu is available. The span of cpus to |
959 | * search starts with cpus closest then further out as needed, |
960 | * so we always favor a closer, idle cpu. |
961 | * |
962 | * Returns the CPU we should wake onto. |
963 | */ |
964 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) |
965 | static inline int wake_idle(int cpu, task_t *p) |
966 | { |
967 | cpumask_t tmp; |
968 | struct sched_domain *sd; |
969 | int i; |
970 | |
971 | if (idle_cpu(cpu)) |
972 | return cpu; |
973 | |
974 | for_each_domain(cpu, sd) { |
975 | if (sd->flags & SD_WAKE_IDLE) { |
976 | cpus_and(tmp, sd->span, cpu_online_map); |
977 | cpus_and(tmp, tmp, p->cpus_allowed); |
978 | for_each_cpu_mask(i, tmp) { |
979 | if (idle_cpu(i)) |
980 | return i; |
981 | } |
982 | } |
983 | else break; |
984 | } |
985 | return cpu; |
986 | } |
987 | #else |
988 | static inline int wake_idle(int cpu, task_t *p) |
989 | { |
990 | return cpu; |
991 | } |
992 | #endif |
993 | |
994 | /* |
995 | * cache_delay is the time preemption is delayed in sched_compute mode |
996 | * and is set to a nominal 10ms. |
997 | */ |
998 | static int cache_delay = 10 * HZ / 1000; |
999 | |
1000 | /* |
1001 | * Check to see if p preempts rq->curr and resched if it does. In compute |
1002 | * mode we do not preempt for at least cache_delay and set rq->preempted. |
1003 | */ |
1004 | static void preempt(task_t *p, runqueue_t *rq) |
1005 | { |
1006 | if (p->prio >= rq->curr->prio) |
1007 | return; |
1008 | if (!sched_compute || rq->cache_ticks >= cache_delay || |
1009 | !p->mm || rt_task(p)) |
1010 | resched_task(rq->curr); |
1011 | rq->preempted = 1; |
1012 | } |
1013 | |
1014 | /*** |
1015 | * try_to_wake_up - wake up a thread |
1016 | * @p: the to-be-woken-up thread |
1017 | * @state: the mask of task states that can be woken |
1018 | * @sync: do a synchronous wakeup? |
1019 | * |
1020 | * Put it on the run-queue if it's not already there. The "current" |
1021 | * thread is always on the run-queue (except when the actual |
1022 | * re-schedule is in progress), and as such you're allowed to do |
1023 | * the simpler "current->state = TASK_RUNNING" to mark yourself |
1024 | * runnable without the overhead of this. |
1025 | * |
1026 | * returns failure only if the task is already active. |
1027 | */ |
1028 | static int try_to_wake_up(task_t * p, unsigned int state, int sync) |
1029 | { |
1030 | int cpu, this_cpu, success = 0; |
1031 | unsigned long flags; |
1032 | long old_state; |
1033 | runqueue_t *rq; |
1034 | #ifdef CONFIG_SMP |
1035 | unsigned long load, this_load; |
1036 | struct sched_domain *sd; |
1037 | int new_cpu; |
1038 | #endif |
1039 | |
1040 | rq = task_rq_lock(p, &flags); |
1041 | old_state = p->state; |
1042 | if (!(old_state & state)) |
1043 | goto out; |
1044 | |
1045 | if (task_queued(p)) |
1046 | goto out_running; |
1047 | |
1048 | cpu = task_cpu(p); |
1049 | this_cpu = smp_processor_id(); |
1050 | |
1051 | #ifdef CONFIG_SMP |
1052 | if (unlikely(task_running(rq, p))) |
1053 | goto out_activate; |
1054 | |
1055 | #ifdef CONFIG_SCHEDSTATS |
1056 | schedstat_inc(rq, ttwu_cnt); |
1057 | if (cpu == this_cpu) { |
1058 | schedstat_inc(rq, ttwu_local); |
1059 | } else { |
1060 | for_each_domain(this_cpu, sd) { |
1061 | if (cpu_isset(cpu, sd->span)) { |
1062 | schedstat_inc(sd, ttwu_wake_remote); |
1063 | break; |
1064 | } |
1065 | } |
1066 | } |
1067 | #endif |
1068 | |
1069 | new_cpu = cpu; |
1070 | if (cpu == this_cpu || unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1071 | goto out_set_cpu; |
1072 | |
1073 | load = source_load(cpu); |
1074 | this_load = target_load(this_cpu); |
1075 | |
1076 | /* |
1077 | * If sync wakeup then subtract the (maximum possible) effect of |
1078 | * the currently running task from the load of the current CPU: |
1079 | */ |
1080 | if (sync) |
1081 | this_load -= SCHED_LOAD_SCALE; |
1082 | |
1083 | /* Don't pull the task off an idle CPU to a busy one */ |
1084 | if (load < SCHED_LOAD_SCALE/2 && this_load > SCHED_LOAD_SCALE/2) |
1085 | goto out_set_cpu; |
1086 | |
1087 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1088 | |
1089 | /* |
1090 | * Scan domains for affine wakeup and passive balancing |
1091 | * possibilities. |
1092 | */ |
1093 | for_each_domain(this_cpu, sd) { |
1094 | unsigned int imbalance; |
1095 | /* |
1096 | * Start passive balancing when half the imbalance_pct |
1097 | * limit is reached. |
1098 | */ |
1099 | imbalance = sd->imbalance_pct + (sd->imbalance_pct - 100) / 2; |
1100 | |
1101 | if ((sd->flags & SD_WAKE_AFFINE) && |
1102 | !task_hot(p, rq->timestamp_last_tick, sd)) { |
1103 | /* |
1104 | * This domain has SD_WAKE_AFFINE and p is cache cold |
1105 | * in this domain. |
1106 | */ |
1107 | if (cpu_isset(cpu, sd->span)) { |
1108 | schedstat_inc(sd, ttwu_move_affine); |
1109 | goto out_set_cpu; |
1110 | } |
1111 | } else if ((sd->flags & SD_WAKE_BALANCE) && |
1112 | imbalance*this_load <= 100*load) { |
1113 | /* |
1114 | * This domain has SD_WAKE_BALANCE and there is |
1115 | * an imbalance. |
1116 | */ |
1117 | if (cpu_isset(cpu, sd->span)) { |
1118 | schedstat_inc(sd, ttwu_move_balance); |
1119 | goto out_set_cpu; |
1120 | } |
1121 | } |
1122 | } |
1123 | |
1124 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ |
1125 | out_set_cpu: |
1126 | new_cpu = wake_idle(new_cpu, p); |
1127 | if (new_cpu != cpu) { |
1128 | set_task_cpu(p, new_cpu); |
1129 | task_rq_unlock(rq, &flags); |
1130 | /* might preempt at this point */ |
1131 | rq = task_rq_lock(p, &flags); |
1132 | old_state = p->state; |
1133 | if (!(old_state & state)) |
1134 | goto out; |
1135 | if (task_queued(p)) |
1136 | goto out_running; |
1137 | |
1138 | this_cpu = smp_processor_id(); |
1139 | cpu = task_cpu(p); |
1140 | } |
1141 | |
1142 | out_activate: |
1143 | #endif /* CONFIG_SMP */ |
1144 | if (old_state == TASK_UNINTERRUPTIBLE) |
1145 | rq->nr_uninterruptible--; |
1146 | |
1147 | /* |
1148 | * Tasks that have marked their sleep as noninteractive get |
1149 | * woken up without their sleep counting. |
1150 | */ |
1151 | if (old_state & TASK_NONINTERACTIVE) |
1152 | p->flags |= PF_NONSLEEP; |
1153 | |
1154 | /* |
1155 | * Sync wakeups (i.e. those types of wakeups where the waker |
1156 | * has indicated that it will leave the CPU in short order) |
1157 | * don't trigger a preemption, if the woken up task will run on |
1158 | * this cpu. (in this case the 'I will reschedule' promise of |
1159 | * the waker guarantees that the freshly woken up task is going |
1160 | * to be considered on this CPU.) |
1161 | */ |
1162 | activate_task(p, rq, cpu == this_cpu); |
1163 | if (!sync || cpu != this_cpu) { |
1164 | preempt(p, rq); |
1165 | } |
1166 | success = 1; |
1167 | |
1168 | out_running: |
1169 | p->state = TASK_RUNNING; |
1170 | out: |
1171 | task_rq_unlock(rq, &flags); |
1172 | |
1173 | return success; |
1174 | } |
1175 | |
1176 | int fastcall wake_up_process(task_t * p) |
1177 | { |
1178 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | |
1179 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); |
1180 | } |
1181 | |
1182 | EXPORT_SYMBOL(wake_up_process); |
1183 | |
1184 | int fastcall wake_up_state(task_t *p, unsigned int state) |
1185 | { |
1186 | return try_to_wake_up(p, state, 0); |
1187 | } |
1188 | |
1189 | #ifdef CONFIG_SMP |
1190 | static int find_idlest_cpu(struct task_struct *p, int this_cpu, |
1191 | struct sched_domain *sd); |
1192 | #endif |
1193 | |
1194 | /* |
1195 | * Perform scheduler related setup for a newly forked process p. |
1196 | * p is forked by current. |
1197 | */ |
1198 | void fastcall sched_fork(task_t *p) |
1199 | { |
1200 | /* |
1201 | * We mark the process as running here, but have not actually |
1202 | * inserted it onto the runqueue yet. This guarantees that |
1203 | * nobody will actually run it, and a signal or other external |
1204 | * event cannot wake it up and insert it on the runqueue either. |
1205 | */ |
1206 | p->state = TASK_RUNNING; |
1207 | INIT_LIST_HEAD(&p->run_list); |
1208 | spin_lock_init(&p->switch_lock); |
1209 | #ifdef CONFIG_SCHEDSTATS |
1210 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1211 | #endif |
1212 | #ifdef CONFIG_PREEMPT |
1213 | /* |
1214 | * During context-switch we hold precisely one spinlock, which |
1215 | * schedule_tail drops. (in the common case it's this_rq()->lock, |
1216 | * but it also can be p->switch_lock.) So we compensate with a count |
1217 | * of 1. Also, we want to start with kernel preemption disabled. |
1218 | */ |
1219 | p->thread_info->preempt_count = 1; |
1220 | #endif |
1221 | } |
1222 | |
1223 | /* |
1224 | * wake_up_new_task - wake up a newly created task for the first time. |
1225 | * |
1226 | * This function will do some initial scheduler statistics housekeeping |
1227 | * that must be done for every newly created context, then puts the task |
1228 | * on the runqueue and wakes it. |
1229 | */ |
1230 | void fastcall wake_up_new_task(task_t * p, unsigned long clone_flags) |
1231 | { |
1232 | unsigned long flags; |
1233 | int this_cpu, cpu; |
1234 | runqueue_t *rq, *this_rq; |
1235 | |
1236 | rq = task_rq_lock(p, &flags); |
1237 | cpu = task_cpu(p); |
1238 | this_cpu = smp_processor_id(); |
1239 | |
1240 | BUG_ON(p->state != TASK_RUNNING); |
1241 | |
1242 | /* |
1243 | * Forked process gets no burst to prevent fork bombs. |
1244 | */ |
1245 | p->burst = 0; |
1246 | |
1247 | if (likely(cpu == this_cpu)) { |
1248 | current->flags |= PF_NONSLEEP; |
1249 | activate_task(p, rq, 1); |
1250 | if (!(clone_flags & CLONE_VM)) |
1251 | /* |
1252 | * The VM isn't cloned, so we're in a good position to |
1253 | * do child-runs-first in anticipation of an exec. This |
1254 | * usually avoids a lot of COW overhead. |
1255 | */ |
1256 | set_need_resched(); |
1257 | /* |
1258 | * We skip the following code due to cpu == this_cpu |
1259 | * |
1260 | * task_rq_unlock(rq, &flags); |
1261 | * this_rq = task_rq_lock(current, &flags); |
1262 | */ |
1263 | this_rq = rq; |
1264 | } else { |
1265 | this_rq = cpu_rq(this_cpu); |
1266 | |
1267 | /* |
1268 | * Not the local CPU - must adjust timestamp. This should |
1269 | * get optimised away in the !CONFIG_SMP case. |
1270 | */ |
1271 | p->timestamp = (p->timestamp - this_rq->timestamp_last_tick) |
1272 | + rq->timestamp_last_tick; |
1273 | activate_task(p, rq, 0); |
1274 | preempt(p, rq); |
1275 | |
1276 | /* |
1277 | * Parent and child are on different CPUs, now get the |
1278 | * parent runqueue to update the parent's ->flags: |
1279 | */ |
1280 | task_rq_unlock(rq, &flags); |
1281 | this_rq = task_rq_lock(current, &flags); |
1282 | current->flags |= PF_NONSLEEP; |
1283 | } |
1284 | task_rq_unlock(this_rq, &flags); |
1285 | } |
1286 | |
1287 | /** |
1288 | * finish_task_switch - clean up after a task-switch |
1289 | * @prev: the thread we just switched away from. |
1290 | * |
1291 | * We enter this with the runqueue still locked, and finish_arch_switch() |
1292 | * will unlock it along with doing any other architecture-specific cleanup |
1293 | * actions. |
1294 | * |
1295 | * Note that we may have delayed dropping an mm in context_switch(). If |
1296 | * so, we finish that here outside of the runqueue lock. (Doing it |
1297 | * with the lock held can cause deadlocks; see schedule() for |
1298 | * details.) |
1299 | */ |
1300 | static inline void finish_task_switch(task_t *prev) |
1301 | __releases(rq->lock) |
1302 | { |
1303 | runqueue_t *rq = this_rq(); |
1304 | struct mm_struct *mm = rq->prev_mm; |
1305 | unsigned long prev_task_flags; |
1306 | |
1307 | rq->prev_mm = NULL; |
1308 | |
1309 | /* |
1310 | * A task struct has one reference for the use as "current". |
1311 | * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and |
1312 | * calls schedule one last time. The schedule call will never return, |
1313 | * and the scheduled task must drop that reference. |
1314 | * The test for EXIT_ZOMBIE must occur while the runqueue locks are |
1315 | * still held, otherwise prev could be scheduled on another cpu, die |
1316 | * there before we look at prev->state, and then the reference would |
1317 | * be dropped twice. |
1318 | * Manfred Spraul <manfred@colorfullife.com> |
1319 | */ |
1320 | prev_task_flags = prev->flags; |
1321 | finish_arch_switch(rq, prev); |
1322 | if (mm) |
1323 | mmdrop(mm); |
1324 | if (unlikely(prev_task_flags & PF_DEAD)) |
1325 | put_task_struct(prev); |
1326 | } |
1327 | |
1328 | /** |
1329 | * schedule_tail - first thing a freshly forked thread must call. |
1330 | * @prev: the thread we just switched away from. |
1331 | */ |
1332 | asmlinkage void schedule_tail(task_t *prev) |
1333 | __releases(rq->lock) |
1334 | { |
1335 | finish_task_switch(prev); |
1336 | |
1337 | if (current->set_child_tid) |
1338 | put_user(current->pid, current->set_child_tid); |
1339 | } |
1340 | |
1341 | /* |
1342 | * context_switch - switch to the new MM and the new |
1343 | * thread's register state. |
1344 | */ |
1345 | static inline |
1346 | task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next) |
1347 | { |
1348 | struct mm_struct *mm = next->mm; |
1349 | struct mm_struct *oldmm = prev->active_mm; |
1350 | |
1351 | if (unlikely(!mm)) { |
1352 | next->active_mm = oldmm; |
1353 | atomic_inc(&oldmm->mm_count); |
1354 | enter_lazy_tlb(oldmm, next); |
1355 | } else |
1356 | switch_mm(oldmm, mm, next); |
1357 | |
1358 | if (unlikely(!prev->mm)) { |
1359 | prev->active_mm = NULL; |
1360 | WARN_ON(rq->prev_mm); |
1361 | rq->prev_mm = oldmm; |
1362 | } |
1363 | |
1364 | /* Here we just switch the register state and the stack. */ |
1365 | switch_to(prev, next, prev); |
1366 | |
1367 | return prev; |
1368 | } |
1369 | |
1370 | /* |
1371 | * nr_running, nr_uninterruptible and nr_context_switches: |
1372 | * |
1373 | * externally visible scheduler statistics: current number of runnable |
1374 | * threads, current number of uninterruptible-sleeping threads, total |
1375 | * number of context switches performed since bootup. |
1376 | */ |
1377 | unsigned long nr_running(void) |
1378 | { |
1379 | unsigned long i, sum = 0; |
1380 | |
1381 | for_each_online_cpu(i) |
1382 | sum += cpu_rq(i)->nr_running; |
1383 | |
1384 | return sum; |
1385 | } |
1386 | |
1387 | unsigned long nr_uninterruptible(void) |
1388 | { |
1389 | unsigned long i, sum = 0; |
1390 | |
1391 | for_each_cpu(i) |
1392 | sum += cpu_rq(i)->nr_uninterruptible; |
1393 | |
1394 | /* |
1395 | * Since we read the counters lockless, it might be slightly |
1396 | * inaccurate. Do not allow it to go below zero though: |
1397 | */ |
1398 | if (unlikely((long)sum < 0)) |
1399 | sum = 0; |
1400 | |
1401 | return sum; |
1402 | } |
1403 | |
1404 | unsigned long long nr_context_switches(void) |
1405 | { |
1406 | unsigned long long i, sum = 0; |
1407 | |
1408 | for_each_cpu(i) |
1409 | sum += cpu_rq(i)->nr_switches; |
1410 | |
1411 | return sum; |
1412 | } |
1413 | |
1414 | unsigned long nr_iowait(void) |
1415 | { |
1416 | unsigned long i, sum = 0; |
1417 | |
1418 | for_each_cpu(i) |
1419 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1420 | |
1421 | return sum; |
1422 | } |
1423 | |
1424 | #ifdef CONFIG_SMP |
1425 | |
1426 | /* |
1427 | * double_rq_lock - safely lock two runqueues |
1428 | * |
1429 | * Note this does not disable interrupts like task_rq_lock, |
1430 | * you need to do so manually before calling. |
1431 | */ |
1432 | static void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2) |
1433 | __acquires(rq1->lock) |
1434 | __acquires(rq2->lock) |
1435 | { |
1436 | if (rq1 == rq2) { |
1437 | spin_lock(&rq1->lock); |
1438 | __acquire(rq2->lock); /* Fake it out ;) */ |
1439 | } else { |
1440 | if (rq1 < rq2) { |
1441 | spin_lock(&rq1->lock); |
1442 | spin_lock(&rq2->lock); |
1443 | } else { |
1444 | spin_lock(&rq2->lock); |
1445 | spin_lock(&rq1->lock); |
1446 | } |
1447 | } |
1448 | } |
1449 | |
1450 | /* |
1451 | * double_rq_unlock - safely unlock two runqueues |
1452 | * |
1453 | * Note this does not restore interrupts like task_rq_unlock, |
1454 | * you need to do so manually after calling. |
1455 | */ |
1456 | static void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2) |
1457 | __releases(rq1->lock) |
1458 | __releases(rq2->lock) |
1459 | { |
1460 | spin_unlock(&rq1->lock); |
1461 | if (rq1 != rq2) |
1462 | spin_unlock(&rq2->lock); |
1463 | else |
1464 | __release(rq2->lock); |
1465 | } |
1466 | |
1467 | /* |
1468 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. |
1469 | */ |
1470 | static void double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest) |
1471 | __releases(this_rq->lock) |
1472 | __acquires(busiest->lock) |
1473 | __acquires(this_rq->lock) |
1474 | { |
1475 | if (unlikely(!spin_trylock(&busiest->lock))) { |
1476 | if (busiest < this_rq) { |
1477 | spin_unlock(&this_rq->lock); |
1478 | spin_lock(&busiest->lock); |
1479 | spin_lock(&this_rq->lock); |
1480 | } else |
1481 | spin_lock(&busiest->lock); |
1482 | } |
1483 | } |
1484 | |
1485 | /* |
1486 | * find_idlest_cpu - find the least busy runqueue. |
1487 | */ |
1488 | static int find_idlest_cpu(struct task_struct *p, int this_cpu, |
1489 | struct sched_domain *sd) |
1490 | { |
1491 | unsigned long load, min_load, this_load; |
1492 | int i, min_cpu; |
1493 | cpumask_t mask; |
1494 | |
1495 | min_cpu = UINT_MAX; |
1496 | min_load = ULONG_MAX; |
1497 | |
1498 | cpus_and(mask, sd->span, p->cpus_allowed); |
1499 | |
1500 | for_each_cpu_mask(i, mask) { |
1501 | load = target_load(i); |
1502 | |
1503 | if (load < min_load) { |
1504 | min_cpu = i; |
1505 | min_load = load; |
1506 | |
1507 | /* break out early on an idle CPU: */ |
1508 | if (!min_load) |
1509 | break; |
1510 | } |
1511 | } |
1512 | |
1513 | /* add +1 to account for the new task */ |
1514 | this_load = source_load(this_cpu) + SCHED_LOAD_SCALE; |
1515 | |
1516 | /* |
1517 | * Would with the addition of the new task to the |
1518 | * current CPU there be an imbalance between this |
1519 | * CPU and the idlest CPU? |
1520 | * |
1521 | * Use half of the balancing threshold - new-context is |
1522 | * a good opportunity to balance. |
1523 | */ |
1524 | if (min_load*(100 + (sd->imbalance_pct-100)/2) < this_load*100) |
1525 | return min_cpu; |
1526 | |
1527 | return this_cpu; |
1528 | } |
1529 | |
1530 | /* |
1531 | * If dest_cpu is allowed for this process, migrate the task to it. |
1532 | * This is accomplished by forcing the cpu_allowed mask to only |
1533 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
1534 | * the cpu_allowed mask is restored. |
1535 | */ |
1536 | static inline void sched_migrate_task(task_t *p, int dest_cpu) |
1537 | { |
1538 | migration_req_t req; |
1539 | runqueue_t *rq; |
1540 | unsigned long flags; |
1541 | |
1542 | rq = task_rq_lock(p, &flags); |
1543 | if (!cpu_isset(dest_cpu, p->cpus_allowed) |
1544 | || unlikely(cpu_is_offline(dest_cpu))) |
1545 | goto out; |
1546 | |
1547 | /* force the process onto the specified CPU */ |
1548 | if (migrate_task(p, dest_cpu, &req)) { |
1549 | /* Need to wait for migration thread (might exit: take ref). */ |
1550 | struct task_struct *mt = rq->migration_thread; |
1551 | get_task_struct(mt); |
1552 | task_rq_unlock(rq, &flags); |
1553 | wake_up_process(mt); |
1554 | put_task_struct(mt); |
1555 | wait_for_completion(&req.done); |
1556 | return; |
1557 | } |
1558 | out: |
1559 | task_rq_unlock(rq, &flags); |
1560 | } |
1561 | |
1562 | /* |
1563 | * sched_exec(): find the highest-level, exec-balance-capable |
1564 | * domain and try to migrate the task to the least loaded CPU. |
1565 | * |
1566 | * execve() is a valuable balancing opportunity, because at this point |
1567 | * the task has the smallest effective memory and cache footprint. |
1568 | */ |
1569 | void sched_exec(void) |
1570 | { |
1571 | struct sched_domain *tmp, *sd = NULL; |
1572 | int new_cpu, this_cpu = get_cpu(); |
1573 | |
1574 | /* Prefer the current CPU if there's only this task running */ |
1575 | if (this_rq()->nr_running <= 1) |
1576 | goto out; |
1577 | |
1578 | for_each_domain(this_cpu, tmp) |
1579 | if (tmp->flags & SD_BALANCE_EXEC) |
1580 | sd = tmp; |
1581 | |
1582 | if (sd) { |
1583 | schedstat_inc(sd, sbe_attempts); |
1584 | new_cpu = find_idlest_cpu(current, this_cpu, sd); |
1585 | if (new_cpu != this_cpu) { |
1586 | schedstat_inc(sd, sbe_pushed); |
1587 | put_cpu(); |
1588 | sched_migrate_task(current, new_cpu); |
1589 | return; |
1590 | } |
1591 | } |
1592 | out: |
1593 | put_cpu(); |
1594 | } |
1595 | |
1596 | /* |
1597 | * pull_task - move a task from a remote runqueue to the local runqueue. |
1598 | * Both runqueues must be locked. |
1599 | */ |
1600 | static inline void pull_task(runqueue_t *src_rq, task_t *p, |
1601 | runqueue_t *this_rq, int this_cpu) |
1602 | { |
1603 | dequeue_task(p, src_rq); |
1604 | dec_nr_running(p, src_rq); |
1605 | set_task_cpu(p, this_cpu); |
1606 | inc_nr_running(p, this_rq); |
1607 | enqueue_task(p, this_rq); |
1608 | p->timestamp = (p->timestamp - src_rq->timestamp_last_tick) |
1609 | + this_rq->timestamp_last_tick; |
1610 | /* |
1611 | * Note that idle threads have a prio of MAX_PRIO, for this test |
1612 | * to be always true for them. |
1613 | */ |
1614 | preempt(p, this_rq); |
1615 | } |
1616 | |
1617 | /* |
1618 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? |
1619 | */ |
1620 | static inline int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu, |
1621 | struct sched_domain *sd, enum idle_type idle) |
1622 | { |
1623 | /* |
1624 | * We do not migrate tasks that are: |
1625 | * 1) running (obviously), or |
1626 | * 2) cannot be migrated to this CPU due to cpus_allowed, or |
1627 | * 3) are cache-hot on their current CPU. |
1628 | */ |
1629 | if (task_running(rq, p)) |
1630 | return 0; |
1631 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
1632 | return 0; |
1633 | |
1634 | /* |
1635 | * Aggressive migration if: |
1636 | * 1) the [whole] cpu is idle, or |
1637 | * 2) too many balance attempts have failed. |
1638 | */ |
1639 | |
1640 | if (cpu_and_siblings_are_idle(this_cpu) || \ |
1641 | sd->nr_balance_failed > sd->cache_nice_tries) |
1642 | return 1; |
1643 | |
1644 | if (task_hot(p, rq->timestamp_last_tick, sd)) |
1645 | return 0; |
1646 | return 1; |
1647 | } |
1648 | |
1649 | /* |
1650 | * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq, |
1651 | * as part of a balancing operation within "domain". Returns the number of |
1652 | * tasks moved. |
1653 | * |
1654 | * Called with both runqueues locked. |
1655 | */ |
1656 | static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest, |
1657 | unsigned long max_nr_move, struct sched_domain *sd, |
1658 | enum idle_type idle) |
1659 | { |
1660 | struct list_head *head, *curr; |
1661 | int idx, pulled = 0; |
1662 | task_t *tmp; |
1663 | |
1664 | if (max_nr_move <= 0 || busiest->nr_running <= 1) |
1665 | goto out; |
1666 | |
1667 | /* Start searching at priority 0: */ |
1668 | idx = 0; |
1669 | skip_bitmap: |
1670 | if (!idx) |
1671 | idx = sched_find_first_bit(busiest->bitmap); |
1672 | else |
1673 | idx = find_next_bit(busiest->bitmap, MAX_PRIO, idx); |
1674 | if (idx >= MAX_PRIO) |
1675 | goto out; |
1676 | |
1677 | head = busiest->queue + idx; |
1678 | curr = head->prev; |
1679 | skip_queue: |
1680 | tmp = list_entry(curr, task_t, run_list); |
1681 | |
1682 | curr = curr->prev; |
1683 | |
1684 | if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle)) { |
1685 | if (curr != head) |
1686 | goto skip_queue; |
1687 | idx++; |
1688 | goto skip_bitmap; |
1689 | } |
1690 | |
1691 | #ifdef CONFIG_SCHEDSTATS |
1692 | if (task_hot(tmp, busiest->timestamp_last_tick, sd)) |
1693 | schedstat_inc(sd, lb_hot_gained[idle]); |
1694 | #endif |
1695 | |
1696 | pull_task(busiest, tmp, this_rq, this_cpu); |
1697 | pulled++; |
1698 | |
1699 | /* We only want to steal up to the prescribed number of tasks. */ |
1700 | if (pulled < max_nr_move) { |
1701 | if (curr != head) |
1702 | goto skip_queue; |
1703 | idx++; |
1704 | goto skip_bitmap; |
1705 | } |
1706 | out: |
1707 | /* |
1708 | * Right now, this is the only place pull_task() is called, |
1709 | * so we can safely collect pull_task() stats here rather than |
1710 | * inside pull_task(). |
1711 | */ |
1712 | schedstat_add(sd, lb_gained[idle], pulled); |
1713 | return pulled; |
1714 | } |
1715 | |
1716 | /* |
1717 | * find_busiest_group finds and returns the busiest CPU group within the |
1718 | * domain. It calculates and returns the number of tasks which should be |
1719 | * moved to restore balance via the imbalance parameter. |
1720 | */ |
1721 | static inline struct sched_group * |
1722 | find_busiest_group(struct sched_domain *sd, int this_cpu, |
1723 | unsigned long *imbalance, enum idle_type idle) |
1724 | { |
1725 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; |
1726 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; |
1727 | |
1728 | max_load = this_load = total_load = total_pwr = 0; |
1729 | |
1730 | do { |
1731 | unsigned long load; |
1732 | int local_group; |
1733 | int i; |
1734 | |
1735 | local_group = cpu_isset(this_cpu, group->cpumask); |
1736 | |
1737 | /* Tally up the load of all CPUs in the group */ |
1738 | avg_load = 0; |
1739 | |
1740 | for_each_cpu_mask(i, group->cpumask) { |
1741 | /* Bias balancing toward cpus of our domain */ |
1742 | if (local_group) |
1743 | load = __target_load(i, idle); |
1744 | else |
1745 | load = __source_load(i, idle); |
1746 | |
1747 | avg_load += load; |
1748 | } |
1749 | |
1750 | total_load += avg_load; |
1751 | total_pwr += group->cpu_power; |
1752 | |
1753 | /* Adjust by relative CPU power of the group */ |
1754 | avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; |
1755 | |
1756 | if (local_group) { |
1757 | this_load = avg_load; |
1758 | this = group; |
1759 | goto nextgroup; |
1760 | } else if (avg_load > max_load) { |
1761 | max_load = avg_load; |
1762 | busiest = group; |
1763 | } |
1764 | nextgroup: |
1765 | group = group->next; |
1766 | } while (group != sd->groups); |
1767 | |
1768 | if (!busiest || this_load >= max_load) |
1769 | goto out_balanced; |
1770 | |
1771 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; |
1772 | |
1773 | if (this_load >= avg_load || |
1774 | 100*max_load <= sd->imbalance_pct*this_load) |
1775 | goto out_balanced; |
1776 | |
1777 | /* |
1778 | * We're trying to get all the cpus to the average_load, so we don't |
1779 | * want to push ourselves above the average load, nor do we wish to |
1780 | * reduce the max loaded cpu below the average load, as either of these |
1781 | * actions would just result in more rebalancing later, and ping-pong |
1782 | * tasks around. Thus we look for the minimum possible imbalance. |
1783 | * Negative imbalances (*we* are more loaded than anyone else) will |
1784 | * be counted as no imbalance for these purposes -- we can't fix that |
1785 | * by pulling tasks to us. Be careful of negative numbers as they'll |
1786 | * appear as very large values with unsigned longs. |
1787 | */ |
1788 | /* How much load to actually move to equalise the imbalance */ |
1789 | *imbalance = min((max_load - avg_load) * busiest->cpu_power, |
1790 | (avg_load - this_load) * this->cpu_power) |
1791 | / SCHED_LOAD_SCALE; |
1792 | |
1793 | if (*imbalance < SCHED_LOAD_SCALE) { |
1794 | unsigned long pwr_now = 0, pwr_move = 0; |
1795 | unsigned long tmp; |
1796 | |
1797 | if (max_load - this_load >= SCHED_LOAD_SCALE*2) { |
1798 | *imbalance = 1; |
1799 | return busiest; |
1800 | } |
1801 | |
1802 | /* |
1803 | * OK, we don't have enough imbalance to justify moving tasks, |
1804 | * however we may be able to increase total CPU power used by |
1805 | * moving them. |
1806 | */ |
1807 | |
1808 | pwr_now += busiest->cpu_power*min(SCHED_LOAD_SCALE, max_load); |
1809 | pwr_now += this->cpu_power*min(SCHED_LOAD_SCALE, this_load); |
1810 | pwr_now /= SCHED_LOAD_SCALE; |
1811 | |
1812 | /* Amount of load we'd subtract */ |
1813 | tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/busiest->cpu_power; |
1814 | if (max_load > tmp) |
1815 | pwr_move += busiest->cpu_power*min(SCHED_LOAD_SCALE, |
1816 | max_load - tmp); |
1817 | |
1818 | /* Amount of load we'd add */ |
1819 | if (max_load*busiest->cpu_power < |
1820 | SCHED_LOAD_SCALE*SCHED_LOAD_SCALE) |
1821 | tmp = max_load*busiest->cpu_power/this->cpu_power; |
1822 | else |
1823 | tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power; |
1824 | pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp); |
1825 | pwr_move /= SCHED_LOAD_SCALE; |
1826 | |
1827 | /* Move if we gain throughput */ |
1828 | if (pwr_move <= pwr_now) |
1829 | goto out_balanced; |
1830 | |
1831 | *imbalance = 1; |
1832 | return busiest; |
1833 | } |
1834 | |
1835 | /* Get rid of the scaling factor, rounding down as we divide */ |
1836 | *imbalance = *imbalance / SCHED_LOAD_SCALE; |
1837 | |
1838 | return busiest; |
1839 | |
1840 | out_balanced: |
1841 | if (busiest && (idle == NEWLY_IDLE || |
1842 | (idle == SCHED_IDLE && max_load > SCHED_LOAD_SCALE)) ) { |
1843 | *imbalance = 1; |
1844 | return busiest; |
1845 | } |
1846 | |
1847 | *imbalance = 0; |
1848 | return NULL; |
1849 | } |
1850 | |
1851 | /* |
1852 | * find_busiest_queue - find the busiest runqueue among the cpus in group. |
1853 | */ |
1854 | static runqueue_t *find_busiest_queue(struct sched_group *group, |
1855 | enum idle_type idle) |
1856 | { |
1857 | unsigned long load, max_load = 0; |
1858 | runqueue_t *busiest = NULL; |
1859 | int i; |
1860 | |
1861 | for_each_cpu_mask(i, group->cpumask) { |
1862 | load = __source_load(i, idle); |
1863 | |
1864 | if (load > max_load) { |
1865 | max_load = load; |
1866 | busiest = cpu_rq(i); |
1867 | } |
1868 | } |
1869 | |
1870 | return busiest; |
1871 | } |
1872 | |
1873 | /* |
1874 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
1875 | * tasks if there is an imbalance. |
1876 | * |
1877 | * Called with this_rq unlocked. |
1878 | */ |
1879 | static inline int load_balance(int this_cpu, runqueue_t *this_rq, |
1880 | struct sched_domain *sd, enum idle_type idle) |
1881 | { |
1882 | struct sched_group *group; |
1883 | runqueue_t *busiest; |
1884 | unsigned long imbalance; |
1885 | int nr_moved; |
1886 | |
1887 | spin_lock(&this_rq->lock); |
1888 | schedstat_inc(sd, lb_cnt[idle]); |
1889 | |
1890 | group = find_busiest_group(sd, this_cpu, &imbalance, idle); |
1891 | if (!group) { |
1892 | schedstat_inc(sd, lb_nobusyg[idle]); |
1893 | goto out_balanced; |
1894 | } |
1895 | |
1896 | busiest = find_busiest_queue(group, idle); |
1897 | if (!busiest) { |
1898 | schedstat_inc(sd, lb_nobusyq[idle]); |
1899 | goto out_balanced; |
1900 | } |
1901 | |
1902 | /* |
1903 | * This should be "impossible", but since load |
1904 | * balancing is inherently racy and statistical, |
1905 | * it could happen in theory. |
1906 | */ |
1907 | if (unlikely(busiest == this_rq)) { |
1908 | WARN_ON(1); |
1909 | goto out_balanced; |
1910 | } |
1911 | |
1912 | schedstat_add(sd, lb_imbalance[idle], imbalance); |
1913 | |
1914 | nr_moved = 0; |
1915 | if (busiest->nr_running > 1) { |
1916 | /* |
1917 | * Attempt to move tasks. If find_busiest_group has found |
1918 | * an imbalance but busiest->nr_running <= 1, the group is |
1919 | * still unbalanced. nr_moved simply stays zero, so it is |
1920 | * correctly treated as an imbalance. |
1921 | */ |
1922 | double_lock_balance(this_rq, busiest); |
1923 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
1924 | imbalance, sd, idle); |
1925 | spin_unlock(&busiest->lock); |
1926 | } |
1927 | spin_unlock(&this_rq->lock); |
1928 | |
1929 | if (!nr_moved) { |
1930 | schedstat_inc(sd, lb_failed[idle]); |
1931 | sd->nr_balance_failed++; |
1932 | |
1933 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { |
1934 | int wake = 0; |
1935 | |
1936 | spin_lock(&busiest->lock); |
1937 | if (!busiest->active_balance) { |
1938 | busiest->active_balance = 1; |
1939 | busiest->push_cpu = this_cpu; |
1940 | wake = 1; |
1941 | } |
1942 | spin_unlock(&busiest->lock); |
1943 | if (wake) |
1944 | wake_up_process(busiest->migration_thread); |
1945 | |
1946 | /* |
1947 | * We've kicked active balancing, reset the failure |
1948 | * counter. |
1949 | */ |
1950 | sd->nr_balance_failed = sd->cache_nice_tries; |
1951 | } |
1952 | |
1953 | /* |
1954 | * We were unbalanced, but unsuccessful in move_tasks(), |
1955 | * so bump the balance_interval to lessen the lock contention. |
1956 | */ |
1957 | if (sd->balance_interval < sd->max_interval) |
1958 | sd->balance_interval++; |
1959 | } else { |
1960 | sd->nr_balance_failed = 0; |
1961 | |
1962 | /* We were unbalanced, so reset the balancing interval */ |
1963 | sd->balance_interval = sd->min_interval; |
1964 | } |
1965 | |
1966 | return nr_moved; |
1967 | |
1968 | out_balanced: |
1969 | spin_unlock(&this_rq->lock); |
1970 | |
1971 | schedstat_inc(sd, lb_balanced[idle]); |
1972 | |
1973 | /* tune up the balancing interval */ |
1974 | if (sd->balance_interval < sd->max_interval) |
1975 | sd->balance_interval *= 2; |
1976 | |
1977 | return 0; |
1978 | } |
1979 | |
1980 | /* |
1981 | * Check this_cpu to ensure it is balanced within domain. Attempt to move |
1982 | * tasks if there is an imbalance. |
1983 | * |
1984 | * Called from schedule when this_rq is about to become idle (NEWLY_IDLE). |
1985 | * this_rq is locked. |
1986 | */ |
1987 | static inline int load_balance_newidle(int this_cpu, runqueue_t *this_rq, |
1988 | struct sched_domain *sd) |
1989 | { |
1990 | struct sched_group *group; |
1991 | runqueue_t *busiest = NULL; |
1992 | unsigned long imbalance; |
1993 | int nr_moved = 0; |
1994 | |
1995 | schedstat_inc(sd, lb_cnt[NEWLY_IDLE]); |
1996 | group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE); |
1997 | if (!group) { |
1998 | schedstat_inc(sd, lb_balanced[NEWLY_IDLE]); |
1999 | schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]); |
2000 | goto out; |
2001 | } |
2002 | |
2003 | busiest = find_busiest_queue(group, NEWLY_IDLE); |
2004 | if (!busiest || busiest == this_rq) { |
2005 | schedstat_inc(sd, lb_balanced[NEWLY_IDLE]); |
2006 | schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]); |
2007 | goto out; |
2008 | } |
2009 | |
2010 | /* Attempt to move tasks */ |
2011 | double_lock_balance(this_rq, busiest); |
2012 | |
2013 | schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance); |
2014 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
2015 | imbalance, sd, NEWLY_IDLE); |
2016 | if (!nr_moved) |
2017 | schedstat_inc(sd, lb_failed[NEWLY_IDLE]); |
2018 | |
2019 | spin_unlock(&busiest->lock); |
2020 | |
2021 | out: |
2022 | return nr_moved; |
2023 | } |
2024 | |
2025 | /* |
2026 | * idle_balance is called by schedule() if this_cpu is about to become |
2027 | * idle. Attempts to pull tasks from other CPUs. |
2028 | */ |
2029 | static inline void idle_balance(int this_cpu, runqueue_t *this_rq) |
2030 | { |
2031 | struct sched_domain *sd; |
2032 | |
2033 | for_each_domain(this_cpu, sd) { |
2034 | if (sd->flags & SD_BALANCE_NEWIDLE) { |
2035 | if (load_balance_newidle(this_cpu, this_rq, sd)) { |
2036 | /* We've pulled tasks over so stop searching */ |
2037 | break; |
2038 | } |
2039 | } |
2040 | } |
2041 | } |
2042 | |
2043 | /* |
2044 | * active_load_balance is run by migration threads. It pushes running tasks |
2045 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be |
2046 | * running on each physical CPU where possible, and avoids physical / |
2047 | * logical imbalances. |
2048 | * |
2049 | * Called with busiest_rq locked. |
2050 | */ |
2051 | static inline void active_load_balance(runqueue_t *busiest_rq, int busiest_cpu) |
2052 | { |
2053 | struct sched_domain *sd; |
2054 | struct sched_group *cpu_group; |
2055 | runqueue_t *target_rq; |
2056 | cpumask_t visited_cpus; |
2057 | int cpu; |
2058 | |
2059 | /* |
2060 | * Search for suitable CPUs to push tasks to in successively higher |
2061 | * domains with SD_LOAD_BALANCE set. |
2062 | */ |
2063 | visited_cpus = CPU_MASK_NONE; |
2064 | for_each_domain(busiest_cpu, sd) { |
2065 | if (!(sd->flags & SD_LOAD_BALANCE)) |
2066 | /* no more domains to search */ |
2067 | break; |
2068 | |
2069 | schedstat_inc(sd, alb_cnt); |
2070 | |
2071 | cpu_group = sd->groups; |
2072 | do { |
2073 | for_each_cpu_mask(cpu, cpu_group->cpumask) { |
2074 | if (busiest_rq->nr_running <= 1) |
2075 | /* no more tasks left to move */ |
2076 | return; |
2077 | if (cpu_isset(cpu, visited_cpus)) |
2078 | continue; |
2079 | cpu_set(cpu, visited_cpus); |
2080 | if (!cpu_and_siblings_are_idle(cpu) || cpu == busiest_cpu) |
2081 | continue; |
2082 | |
2083 | target_rq = cpu_rq(cpu); |
2084 | /* |
2085 | * This condition is "impossible", if it occurs |
2086 | * we need to fix it. Originally reported by |
2087 | * Bjorn Helgaas on a 128-cpu setup. |
2088 | */ |
2089 | BUG_ON(busiest_rq == target_rq); |
2090 | |
2091 | /* move a task from busiest_rq to target_rq */ |
2092 | double_lock_balance(busiest_rq, target_rq); |
2093 | if (move_tasks(target_rq, cpu, busiest_rq, |
2094 | 1, sd, SCHED_IDLE)) { |
2095 | schedstat_inc(sd, alb_pushed); |
2096 | } else { |
2097 | schedstat_inc(sd, alb_failed); |
2098 | } |
2099 | spin_unlock(&target_rq->lock); |
2100 | } |
2101 | cpu_group = cpu_group->next; |
2102 | } while (cpu_group != sd->groups); |
2103 | } |
2104 | } |
2105 | |
2106 | /* |
2107 | * rebalance_tick will get called every timer tick, on every CPU. |
2108 | * |
2109 | * It checks each scheduling domain to see if it is due to be balanced, |
2110 | * and initiates a balancing operation if so. |
2111 | * |
2112 | * Balancing parameters are set up in arch_init_sched_domains. |
2113 | */ |
2114 | |
2115 | /* Don't have all balancing operations going off at once */ |
2116 | #define CPU_OFFSET(cpu) (HZ * cpu / NR_CPUS) |
2117 | |
2118 | static void rebalance_tick(int this_cpu, runqueue_t *this_rq, |
2119 | enum idle_type idle) |
2120 | { |
2121 | unsigned long old_load, this_load; |
2122 | unsigned long j = jiffies + CPU_OFFSET(this_cpu); |
2123 | struct sched_domain *sd; |
2124 | |
2125 | /* Update our load */ |
2126 | old_load = this_rq->cpu_load; |
2127 | this_load = this_rq->nr_running * SCHED_LOAD_SCALE; |
2128 | /* |
2129 | * Round up the averaging division if load is increasing. This |
2130 | * prevents us from getting stuck on 9 if the load is 10, for |
2131 | * example. |
2132 | */ |
2133 | if (this_load > old_load) |
2134 | old_load++; |
2135 | this_rq->cpu_load = (old_load + this_load) / 2; |
2136 | |
2137 | for_each_domain(this_cpu, sd) { |
2138 | unsigned long interval; |
2139 | |
2140 | if (!(sd->flags & SD_LOAD_BALANCE)) |
2141 | continue; |
2142 | |
2143 | interval = sd->balance_interval; |
2144 | |
2145 | /* scale ms to jiffies */ |
2146 | interval = msecs_to_jiffies(interval); |
2147 | if (unlikely(!interval)) |
2148 | interval = 1; |
2149 | |
2150 | if (idle != SCHED_IDLE || j - sd->last_balance >= interval) { |
2151 | if (load_balance(this_cpu, this_rq, sd, idle)) { |
2152 | /* We've pulled tasks over so no longer idle */ |
2153 | idle = NOT_IDLE; |
2154 | } |
2155 | sd->last_balance += interval; |
2156 | } |
2157 | } |
2158 | } |
2159 | #else |
2160 | /* |
2161 | * on UP we do not need to balance between CPUs: |
2162 | */ |
2163 | static inline void rebalance_tick(int cpu, runqueue_t *rq, enum idle_type idle) |
2164 | { |
2165 | } |
2166 | static inline void idle_balance(int cpu, runqueue_t *rq) |
2167 | { |
2168 | } |
2169 | #endif |
2170 | |
2171 | static inline int wake_priority_sleeper(runqueue_t *rq) |
2172 | { |
2173 | int ret = 0; |
2174 | #ifdef CONFIG_SCHED_SMT |
2175 | spin_lock(&rq->lock); |
2176 | /* |
2177 | * If an SMT sibling task has been put to sleep for priority |
2178 | * reasons reschedule the idle task to see if it can now run. |
2179 | */ |
2180 | if (rq->nr_running) { |
2181 | resched_task(rq->idle); |
2182 | ret = 1; |
2183 | } |
2184 | spin_unlock(&rq->lock); |
2185 | #endif |
2186 | return ret; |
2187 | } |
2188 | |
2189 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
2190 | |
2191 | EXPORT_PER_CPU_SYMBOL(kstat); |
2192 | |
2193 | /* |
2194 | * This is called on clock ticks and on context switches. |
2195 | * Bank in p->sched_time the ns elapsed since the last tick or switch. |
2196 | */ |
2197 | static inline void update_cpu_clock(task_t *p, runqueue_t *rq, |
2198 | unsigned long long now) |
2199 | { |
2200 | unsigned long long last = max(p->timestamp, rq->timestamp_last_tick); |
2201 | p->sched_time += now - last; |
2202 | } |
2203 | |
2204 | /* |
2205 | * Return current->sched_time plus any more ns on the sched_clock |
2206 | * that have not yet been banked. |
2207 | */ |
2208 | unsigned long long current_sched_time(const task_t *tsk) |
2209 | { |
2210 | unsigned long long ns; |
2211 | unsigned long flags; |
2212 | local_irq_save(flags); |
2213 | ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick); |
2214 | ns = tsk->sched_time + (sched_clock() - ns); |
2215 | local_irq_restore(flags); |
2216 | return ns; |
2217 | } |
2218 | |
2219 | /* |
2220 | * Account user cpu time to a process. |
2221 | * @p: the process that the cpu time gets accounted to |
2222 | * @hardirq_offset: the offset to subtract from hardirq_count() |
2223 | * @cputime: the cpu time spent in user space since the last update |
2224 | */ |
2225 | void account_user_time(struct task_struct *p, cputime_t cputime) |
2226 | { |
2227 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
2228 | cputime64_t tmp; |
2229 | |
2230 | p->utime = cputime_add(p->utime, cputime); |
2231 | |
2232 | /* Add user time to cpustat. */ |
2233 | tmp = cputime_to_cputime64(cputime); |
2234 | if (TASK_NICE(p) > 0 || batch_task(p)) |
2235 | cpustat->nice = cputime64_add(cpustat->nice, tmp); |
2236 | else |
2237 | cpustat->user = cputime64_add(cpustat->user, tmp); |
2238 | } |
2239 | |
2240 | /* |
2241 | * Account system cpu time to a process. |
2242 | * @p: the process that the cpu time gets accounted to |
2243 | * @hardirq_offset: the offset to subtract from hardirq_count() |
2244 | * @cputime: the cpu time spent in kernel space since the last update |
2245 | */ |
2246 | void account_system_time(struct task_struct *p, int hardirq_offset, |
2247 | cputime_t cputime) |
2248 | { |
2249 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
2250 | runqueue_t *rq = this_rq(); |
2251 | cputime64_t tmp; |
2252 | |
2253 | p->stime = cputime_add(p->stime, cputime); |
2254 | |
2255 | /* Add system time to cpustat. */ |
2256 | tmp = cputime_to_cputime64(cputime); |
2257 | if (hardirq_count() - hardirq_offset) |
2258 | cpustat->irq = cputime64_add(cpustat->irq, tmp); |
2259 | else if (softirq_count()) |
2260 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); |
2261 | else if (p != rq->idle) |
2262 | cpustat->system = cputime64_add(cpustat->system, tmp); |
2263 | else if (atomic_read(&rq->nr_iowait) > 0) |
2264 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
2265 | else |
2266 | cpustat->idle = cputime64_add(cpustat->idle, tmp); |
2267 | |
2268 | /* Account for system time used */ |
2269 | acct_update_integrals(p); |
2270 | /* Update rss highwater mark */ |
2271 | update_mem_hiwater(p); |
2272 | } |
2273 | |
2274 | /* |
2275 | * Account for involuntary wait time. |
2276 | * @p: the process from which the cpu time has been stolen |
2277 | * @steal: the cpu time spent in involuntary wait |
2278 | */ |
2279 | void account_steal_time(struct task_struct *p, cputime_t steal) |
2280 | { |
2281 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
2282 | cputime64_t tmp = cputime_to_cputime64(steal); |
2283 | runqueue_t *rq = this_rq(); |
2284 | |
2285 | if (p == rq->idle) { |
2286 | p->stime = cputime_add(p->stime, steal); |
2287 | if (atomic_read(&rq->nr_iowait) > 0) |
2288 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
2289 | else |
2290 | cpustat->idle = cputime64_add(cpustat->idle, tmp); |
2291 | } else |
2292 | cpustat->steal = cputime64_add(cpustat->steal, tmp); |
2293 | } |
2294 | |
2295 | static void time_slice_expired(task_t *p, runqueue_t *rq) |
2296 | { |
2297 | set_tsk_need_resched(p); |
2298 | dequeue_task(p, rq); |
2299 | p->prio = effective_prio(p); |
2300 | p->time_slice = rr_interval(p); |
2301 | enqueue_task(p, rq); |
2302 | } |
2303 | |
2304 | /* |
2305 | * This function gets called by the timer code, with HZ frequency. |
2306 | * We call it with interrupts disabled. |
2307 | */ |
2308 | void scheduler_tick(void) |
2309 | { |
2310 | int cpu = smp_processor_id(); |
2311 | runqueue_t *rq = this_rq(); |
2312 | task_t *p = current; |
2313 | unsigned long debit, expired_balance = rq->nr_running; |
2314 | unsigned long long now = sched_clock(); |
2315 | |
2316 | update_cpu_clock(p, rq, now); |
2317 | |
2318 | rq->timestamp_last_tick = now; |
2319 | |
2320 | if (p == rq->idle) { |
2321 | if (wake_priority_sleeper(rq)) |
2322 | goto out; |
2323 | rebalance_tick(cpu, rq, SCHED_IDLE); |
2324 | return; |
2325 | } |
2326 | |
2327 | /* Task might have expired already, but not scheduled off yet */ |
2328 | if (unlikely(!task_queued(p))) { |
2329 | set_tsk_need_resched(p); |
2330 | goto out; |
2331 | } |
2332 | /* |
2333 | * SCHED_FIFO tasks never run out of timeslice. |
2334 | */ |
2335 | if (unlikely(p->policy == SCHED_FIFO)) { |
2336 | expired_balance = 0; |
2337 | goto out; |
2338 | } |
2339 | |
2340 | spin_lock(&rq->lock); |
2341 | debit = ns_diff(rq->timestamp_last_tick, p->timestamp); |
2342 | p->ns_debit += debit; |
2343 | if (p->ns_debit < NSJIFFY) |
2344 | goto out_unlock; |
2345 | p->ns_debit %= NSJIFFY; |
2346 | /* |
2347 | * Tasks lose burst each time they use up a full slice(). |
2348 | */ |
2349 | if (!--p->slice) { |
2350 | dec_burst(p); |
2351 | p->slice = slice(p); |
2352 | time_slice_expired(p, rq); |
2353 | p->totalrun = 0; |
2354 | goto out_unlock; |
2355 | } |
2356 | /* |
2357 | * Tasks that run out of time_slice but still have slice left get |
2358 | * requeued with a lower priority && RR_INTERVAL time_slice. |
2359 | */ |
2360 | if (!--p->time_slice) { |
2361 | time_slice_expired(p, rq); |
2362 | goto out_unlock; |
2363 | } |
2364 | rq->cache_ticks++; |
2365 | if (rq->preempted && rq->cache_ticks >= cache_delay) { |
2366 | set_tsk_need_resched(p); |
2367 | goto out_unlock; |
2368 | } |
2369 | expired_balance = 0; |
2370 | out_unlock: |
2371 | spin_unlock(&rq->lock); |
2372 | out: |
2373 | if (expired_balance > 1) |
2374 | rebalance_tick(cpu, rq, NOT_IDLE); |
2375 | } |
2376 | |
2377 | #ifdef CONFIG_SCHED_SMT |
2378 | static inline void wakeup_busy_runqueue(runqueue_t *rq) |
2379 | { |
2380 | /* If an SMT runqueue is sleeping due to priority reasons wake it up */ |
2381 | if (rq->curr == rq->idle && rq->nr_running) |
2382 | resched_task(rq->idle); |
2383 | } |
2384 | |
2385 | static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq) |
2386 | { |
2387 | struct sched_domain *sd = this_rq->sd; |
2388 | cpumask_t sibling_map; |
2389 | int i; |
2390 | |
2391 | if (!(sd->flags & SD_SHARE_CPUPOWER)) |
2392 | return; |
2393 | |
2394 | /* |
2395 | * Unlock the current runqueue because we have to lock in |
2396 | * CPU order to avoid deadlocks. Caller knows that we might |
2397 | * unlock. We keep IRQs disabled. |
2398 | */ |
2399 | spin_unlock(&this_rq->lock); |
2400 | |
2401 | sibling_map = sd->span; |
2402 | |
2403 | for_each_cpu_mask(i, sibling_map) |
2404 | spin_lock(&cpu_rq(i)->lock); |
2405 | /* |
2406 | * We clear this CPU from the mask. This both simplifies the |
2407 | * inner loop and keps this_rq locked when we exit: |
2408 | */ |
2409 | cpu_clear(this_cpu, sibling_map); |
2410 | |
2411 | for_each_cpu_mask(i, sibling_map) { |
2412 | runqueue_t *smt_rq = cpu_rq(i); |
2413 | |
2414 | wakeup_busy_runqueue(smt_rq); |
2415 | } |
2416 | |
2417 | for_each_cpu_mask(i, sibling_map) |
2418 | spin_unlock(&cpu_rq(i)->lock); |
2419 | /* |
2420 | * We exit with this_cpu's rq still held and IRQs |
2421 | * still disabled: |
2422 | */ |
2423 | } |
2424 | |
2425 | static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq) |
2426 | { |
2427 | struct sched_domain *sd = this_rq->sd; |
2428 | cpumask_t sibling_map; |
2429 | int ret = 0, i; |
2430 | task_t *p; |
2431 | |
2432 | if (!(sd->flags & SD_SHARE_CPUPOWER)) |
2433 | return 0; |
2434 | |
2435 | /* |
2436 | * The same locking rules and details apply as for |
2437 | * wake_sleeping_dependent(): |
2438 | */ |
2439 | spin_unlock(&this_rq->lock); |
2440 | sibling_map = sd->span; |
2441 | for_each_cpu_mask(i, sibling_map) |
2442 | spin_lock(&cpu_rq(i)->lock); |
2443 | cpu_clear(this_cpu, sibling_map); |
2444 | |
2445 | /* |
2446 | * Establish next task to be run - it might have gone away because |
2447 | * we released the runqueue lock above: |
2448 | */ |
2449 | if (!this_rq->nr_running) |
2450 | goto out_unlock; |
2451 | |
2452 | p = list_entry(this_rq->queue[sched_find_first_bit(this_rq->bitmap)].next, |
2453 | task_t, run_list); |
2454 | |
2455 | for_each_cpu_mask(i, sibling_map) { |
2456 | runqueue_t *smt_rq = cpu_rq(i); |
2457 | task_t *smt_curr = smt_rq->curr; |
2458 | |
2459 | /* Kernel threads do not participate in dependent sleeping */ |
2460 | if (!p->mm || !smt_curr->mm || rt_task(p)) |
2461 | goto check_smt_task; |
2462 | |
2463 | /* |
2464 | * If a user task with lower static priority than the |
2465 | * running task on the SMT sibling is trying to schedule, |
2466 | * delay it till there is proportionately less timeslice |
2467 | * left of the sibling task to prevent a lower priority |
2468 | * task from using an unfair proportion of the |
2469 | * physical cpu's resources. -ck |
2470 | */ |
2471 | if (rt_task(smt_curr)) { |
2472 | /* |
2473 | * With real time tasks we run non-rt tasks only |
2474 | * per_cpu_gain% of the time. |
2475 | */ |
2476 | if ((jiffies % DEF_TIMESLICE) > |
2477 | (sd->per_cpu_gain * DEF_TIMESLICE / 100)) |
2478 | ret = 1; |
2479 | else if (batch_task(p)) |
2480 | ret = 1; |
2481 | } else { |
2482 | if (((smt_curr->slice * (100 - sd->per_cpu_gain) / |
2483 | 100) > slice(p))) |
2484 | ret = 1; |
2485 | else if (batch_task(p) && !batch_task(smt_curr) && |
2486 | smt_curr->slice * sd->per_cpu_gain > |
2487 | slice(smt_curr)) |
2488 | /* |
2489 | * With batch tasks they run just the last |
2490 | * per_cpu_gain percent of the smt task's slice. |
2491 | */ |
2492 | ret = 1; |
2493 | } |
2494 | |
2495 | check_smt_task: |
2496 | if ((!smt_curr->mm && smt_curr != smt_rq->idle) || |
2497 | rt_task(smt_curr)) |
2498 | continue; |
2499 | if (!p->mm) { |
2500 | wakeup_busy_runqueue(smt_rq); |
2501 | continue; |
2502 | } |
2503 | |
2504 | /* |
2505 | * Reschedule a lower priority task on the SMT sibling, |
2506 | * or wake it up if it has been put to sleep for priority |
2507 | * reasons to see if it should run now. |
2508 | */ |
2509 | if (rt_task(p)) { |
2510 | if ((jiffies % DEF_TIMESLICE) > |
2511 | (sd->per_cpu_gain * DEF_TIMESLICE / 100)) |
2512 | resched_task(smt_curr); |
2513 | else if (batch_task(smt_curr)) |
2514 | resched_task(smt_curr); |
2515 | } else { |
2516 | if ((p->slice * (100 - sd->per_cpu_gain) / 100) > |
2517 | slice(smt_curr)) |
2518 | resched_task(smt_curr); |
2519 | else if (batch_task(smt_curr) && !batch_task(p) && |
2520 | p->slice * sd->per_cpu_gain > slice(p)) |
2521 | resched_task(smt_curr); |
2522 | else |
2523 | wakeup_busy_runqueue(smt_rq); |
2524 | } |
2525 | } |
2526 | out_unlock: |
2527 | for_each_cpu_mask(i, sibling_map) |
2528 | spin_unlock(&cpu_rq(i)->lock); |
2529 | return ret; |
2530 | } |
2531 | #else |
2532 | static inline void wake_sleeping_dependent(int this_cpu, runqueue_t *this_rq) |
2533 | { |
2534 | } |
2535 | |
2536 | static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq) |
2537 | { |
2538 | return 0; |
2539 | } |
2540 | #endif |
2541 | |
2542 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) |
2543 | |
2544 | void fastcall add_preempt_count(int val) |
2545 | { |
2546 | /* |
2547 | * Underflow? |
2548 | */ |
2549 | BUG_ON(((int)preempt_count() < 0)); |
2550 | preempt_count() += val; |
2551 | /* |
2552 | * Spinlock count overflowing soon? |
2553 | */ |
2554 | BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10); |
2555 | } |
2556 | EXPORT_SYMBOL(add_preempt_count); |
2557 | |
2558 | void fastcall sub_preempt_count(int val) |
2559 | { |
2560 | /* |
2561 | * Underflow? |
2562 | */ |
2563 | BUG_ON(val > preempt_count()); |
2564 | /* |
2565 | * Is the spinlock portion underflowing? |
2566 | */ |
2567 | BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK)); |
2568 | preempt_count() -= val; |
2569 | } |
2570 | EXPORT_SYMBOL(sub_preempt_count); |
2571 | |
2572 | #endif |
2573 | |
2574 | /* |
2575 | * schedule() is the main scheduler function. |
2576 | */ |
2577 | asmlinkage void __sched schedule(void) |
2578 | { |
2579 | long *switch_count; |
2580 | task_t *prev, *next; |
2581 | runqueue_t *rq; |
2582 | struct list_head *queue; |
2583 | unsigned long long now; |
2584 | unsigned long debit; |
2585 | int cpu, idx; |
2586 | |
2587 | /* |
2588 | * Test if we are atomic. Since do_exit() needs to call into |
2589 | * schedule() atomically, we ignore that path for now. |
2590 | * Otherwise, whine if we are scheduling when we should not be. |
2591 | */ |
2592 | if (likely(!current->exit_state)) { |
2593 | if (unlikely(in_atomic())) { |
2594 | printk(KERN_ERR "scheduling while atomic: " |
2595 | "%s/0x%08x/%d\n", |
2596 | current->comm, preempt_count(), current->pid); |
2597 | dump_stack(); |
2598 | } |
2599 | } |
2600 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
2601 | |
2602 | need_resched: |
2603 | preempt_disable(); |
2604 | prev = current; |
2605 | release_kernel_lock(prev); |
2606 | need_resched_nonpreemptible: |
2607 | rq = this_rq(); |
2608 | |
2609 | /* |
2610 | * The idle thread is not allowed to schedule! |
2611 | * Remove this check after it has been exercised a bit. |
2612 | */ |
2613 | if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) { |
2614 | printk(KERN_ERR "bad: scheduling from the idle thread!\n"); |
2615 | dump_stack(); |
2616 | } |
2617 | |
2618 | schedstat_inc(rq, sched_cnt); |
2619 | now = sched_clock(); |
2620 | |
2621 | spin_lock_irq(&rq->lock); |
2622 | prev->runtime = ns_diff(now, prev->timestamp); |
2623 | debit = ns_diff(now, rq->timestamp_last_tick) % NSJIFFY; |
2624 | prev->ns_debit += debit; |
2625 | |
2626 | if (unlikely(prev->flags & PF_DEAD)) |
2627 | prev->state = EXIT_DEAD; |
2628 | |
2629 | switch_count = &prev->nivcsw; |
2630 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
2631 | switch_count = &prev->nvcsw; |
2632 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && |
2633 | unlikely(signal_pending(prev)))) |
2634 | prev->state = TASK_RUNNING; |
2635 | else { |
2636 | if (prev->state == TASK_UNINTERRUPTIBLE) { |
2637 | prev->flags |= PF_NONSLEEP; |
2638 | rq->nr_uninterruptible++; |
2639 | } |
2640 | deactivate_task(prev, rq); |
2641 | } |
2642 | } |
2643 | |
2644 | cpu = smp_processor_id(); |
2645 | if (unlikely(!rq->nr_running)) { |
2646 | go_idle: |
2647 | idle_balance(cpu, rq); |
2648 | if (!rq->nr_running) { |
2649 | next = rq->idle; |
2650 | wake_sleeping_dependent(cpu, rq); |
2651 | /* |
2652 | * wake_sleeping_dependent() might have released |
2653 | * the runqueue, so break out if we got new |
2654 | * tasks meanwhile: |
2655 | */ |
2656 | if (!rq->nr_running) |
2657 | goto switch_tasks; |
2658 | } |
2659 | } else { |
2660 | if (dependent_sleeper(cpu, rq)) { |
2661 | next = rq->idle; |
2662 | goto switch_tasks; |
2663 | } |
2664 | /* |
2665 | * dependent_sleeper() releases and reacquires the runqueue |
2666 | * lock, hence go into the idle loop if the rq went |
2667 | * empty meanwhile: |
2668 | */ |
2669 | if (unlikely(!rq->nr_running)) |
2670 | goto go_idle; |
2671 | } |
2672 | |
2673 | idx = sched_find_first_bit(rq->bitmap); |
2674 | queue = rq->queue + idx; |
2675 | next = list_entry(queue->next, task_t, run_list); |
2676 | |
2677 | switch_tasks: |
2678 | if (next == rq->idle) |
2679 | schedstat_inc(rq, sched_goidle); |
2680 | prev->timestamp = now; |
2681 | if (unlikely(next->flags & PF_YIELDED)) { |
2682 | /* |
2683 | * Tasks that have yield()ed get requeued at normal priority |
2684 | */ |
2685 | int newprio = effective_prio(next); |
2686 | next->flags &= ~PF_YIELDED; |
2687 | if (newprio != next->prio) { |
2688 | dequeue_task(next, rq); |
2689 | next->prio = newprio; |
2690 | enqueue_task(next, rq); |
2691 | } |
2692 | } |
2693 | |
2694 | prefetch(next); |
2695 | clear_tsk_need_resched(prev); |
2696 | rcu_qsctr_inc(task_cpu(prev)); |
2697 | |
2698 | update_cpu_clock(prev, rq, now); |
2699 | |
2700 | sched_info_switch(prev, next); |
2701 | if (likely(prev != next)) { |
2702 | rq->preempted = 0; |
2703 | rq->cache_ticks = 0; |
2704 | next->timestamp = now; |
2705 | rq->nr_switches++; |
2706 | rq->curr = next; |
2707 | ++*switch_count; |
2708 | |
2709 | prepare_arch_switch(rq, next); |
2710 | prev = context_switch(rq, prev, next); |
2711 | barrier(); |
2712 | |
2713 | finish_task_switch(prev); |
2714 | } else |
2715 | spin_unlock_irq(&rq->lock); |
2716 | |
2717 | prev = current; |
2718 | if (unlikely(reacquire_kernel_lock(prev) < 0)) |
2719 | goto need_resched_nonpreemptible; |
2720 | preempt_enable_no_resched(); |
2721 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
2722 | goto need_resched; |
2723 | } |
2724 | |
2725 | EXPORT_SYMBOL(schedule); |
2726 | |
2727 | #ifdef CONFIG_PREEMPT |
2728 | /* |
2729 | * this is is the entry point to schedule() from in-kernel preemption |
2730 | * off of preempt_enable. Kernel preemptions off return from interrupt |
2731 | * occur there and call schedule directly. |
2732 | */ |
2733 | asmlinkage void __sched preempt_schedule(void) |
2734 | { |
2735 | struct thread_info *ti = current_thread_info(); |
2736 | #ifdef CONFIG_PREEMPT_BKL |
2737 | struct task_struct *task = current; |
2738 | int saved_lock_depth; |
2739 | #endif |
2740 | /* |
2741 | * If there is a non-zero preempt_count or interrupts are disabled, |
2742 | * we do not want to preempt the current task. Just return.. |
2743 | */ |
2744 | if (unlikely(ti->preempt_count || irqs_disabled())) |
2745 | return; |
2746 | |
2747 | need_resched: |
2748 | add_preempt_count(PREEMPT_ACTIVE); |
2749 | /* |
2750 | * We keep the big kernel semaphore locked, but we |
2751 | * clear ->lock_depth so that schedule() doesnt |
2752 | * auto-release the semaphore: |
2753 | */ |
2754 | #ifdef CONFIG_PREEMPT_BKL |
2755 | saved_lock_depth = task->lock_depth; |
2756 | task->lock_depth = -1; |
2757 | #endif |
2758 | schedule(); |
2759 | #ifdef CONFIG_PREEMPT_BKL |
2760 | task->lock_depth = saved_lock_depth; |
2761 | #endif |
2762 | sub_preempt_count(PREEMPT_ACTIVE); |
2763 | |
2764 | /* we could miss a preemption opportunity between schedule and now */ |
2765 | barrier(); |
2766 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
2767 | goto need_resched; |
2768 | } |
2769 | |
2770 | EXPORT_SYMBOL(preempt_schedule); |
2771 | |
2772 | /* |
2773 | * this is is the entry point to schedule() from kernel preemption |
2774 | * off of irq context. |
2775 | * Note, that this is called and return with irqs disabled. This will |
2776 | * protect us against recursive calling from irq. |
2777 | */ |
2778 | asmlinkage void __sched preempt_schedule_irq(void) |
2779 | { |
2780 | struct thread_info *ti = current_thread_info(); |
2781 | #ifdef CONFIG_PREEMPT_BKL |
2782 | struct task_struct *task = current; |
2783 | int saved_lock_depth; |
2784 | #endif |
2785 | /* Catch callers which need to be fixed*/ |
2786 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
2787 | |
2788 | need_resched: |
2789 | add_preempt_count(PREEMPT_ACTIVE); |
2790 | /* |
2791 | * We keep the big kernel semaphore locked, but we |
2792 | * clear ->lock_depth so that schedule() doesnt |
2793 | * auto-release the semaphore: |
2794 | */ |
2795 | #ifdef CONFIG_PREEMPT_BKL |
2796 | saved_lock_depth = task->lock_depth; |
2797 | task->lock_depth = -1; |
2798 | #endif |
2799 | local_irq_enable(); |
2800 | schedule(); |
2801 | local_irq_disable(); |
2802 | #ifdef CONFIG_PREEMPT_BKL |
2803 | task->lock_depth = saved_lock_depth; |
2804 | #endif |
2805 | sub_preempt_count(PREEMPT_ACTIVE); |
2806 | |
2807 | /* we could miss a preemption opportunity between schedule and now */ |
2808 | barrier(); |
2809 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
2810 | goto need_resched; |
2811 | } |
2812 | |
2813 | #endif /* CONFIG_PREEMPT */ |
2814 | |
2815 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, void *key) |
2816 | { |
2817 | task_t *p = curr->task; |
2818 | return try_to_wake_up(p, mode, sync); |
2819 | } |
2820 | |
2821 | EXPORT_SYMBOL(default_wake_function); |
2822 | |
2823 | /* |
2824 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
2825 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
2826 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
2827 | * |
2828 | * There are circumstances in which we can try to wake a task which has already |
2829 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
2830 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
2831 | */ |
2832 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
2833 | int nr_exclusive, int sync, void *key) |
2834 | { |
2835 | struct list_head *tmp, *next; |
2836 | |
2837 | list_for_each_safe(tmp, next, &q->task_list) { |
2838 | wait_queue_t *curr; |
2839 | unsigned flags; |
2840 | curr = list_entry(tmp, wait_queue_t, task_list); |
2841 | flags = curr->flags; |
2842 | if (curr->func(curr, mode, sync, key) && |
2843 | (flags & WQ_FLAG_EXCLUSIVE) && |
2844 | !--nr_exclusive) |
2845 | break; |
2846 | } |
2847 | } |
2848 | |
2849 | /** |
2850 | * __wake_up - wake up threads blocked on a waitqueue. |
2851 | * @q: the waitqueue |
2852 | * @mode: which threads |
2853 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
2854 | * @key: is directly passed to the wakeup function |
2855 | */ |
2856 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, |
2857 | int nr_exclusive, void *key) |
2858 | { |
2859 | unsigned long flags; |
2860 | |
2861 | spin_lock_irqsave(&q->lock, flags); |
2862 | __wake_up_common(q, mode, nr_exclusive, 0, key); |
2863 | spin_unlock_irqrestore(&q->lock, flags); |
2864 | } |
2865 | |
2866 | EXPORT_SYMBOL(__wake_up); |
2867 | |
2868 | /* |
2869 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
2870 | */ |
2871 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) |
2872 | { |
2873 | __wake_up_common(q, mode, 1, 0, NULL); |
2874 | } |
2875 | |
2876 | /** |
2877 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
2878 | * @q: the waitqueue |
2879 | * @mode: which threads |
2880 | * @nr_exclusive: how many wake-one or wake-many threads to wake up |
2881 | * |
2882 | * The sync wakeup differs that the waker knows that it will schedule |
2883 | * away soon, so while the target thread will be woken up, it will not |
2884 | * be migrated to another CPU - ie. the two threads are 'synchronized' |
2885 | * with each other. This can prevent needless bouncing between CPUs. |
2886 | * |
2887 | * On UP it can prevent extra preemption. |
2888 | */ |
2889 | void fastcall __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
2890 | { |
2891 | unsigned long flags; |
2892 | int sync = 1; |
2893 | |
2894 | if (unlikely(!q)) |
2895 | return; |
2896 | |
2897 | if (unlikely(!nr_exclusive)) |
2898 | sync = 0; |
2899 | |
2900 | spin_lock_irqsave(&q->lock, flags); |
2901 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); |
2902 | spin_unlock_irqrestore(&q->lock, flags); |
2903 | } |
2904 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
2905 | |
2906 | void fastcall complete(struct completion *x) |
2907 | { |
2908 | unsigned long flags; |
2909 | |
2910 | spin_lock_irqsave(&x->wait.lock, flags); |
2911 | x->done++; |
2912 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, |
2913 | 1, 0, NULL); |
2914 | spin_unlock_irqrestore(&x->wait.lock, flags); |
2915 | } |
2916 | EXPORT_SYMBOL(complete); |
2917 | |
2918 | void fastcall complete_all(struct completion *x) |
2919 | { |
2920 | unsigned long flags; |
2921 | |
2922 | spin_lock_irqsave(&x->wait.lock, flags); |
2923 | x->done += UINT_MAX/2; |
2924 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, |
2925 | 0, 0, NULL); |
2926 | spin_unlock_irqrestore(&x->wait.lock, flags); |
2927 | } |
2928 | EXPORT_SYMBOL(complete_all); |
2929 | |
2930 | void fastcall __sched wait_for_completion(struct completion *x) |
2931 | { |
2932 | might_sleep(); |
2933 | spin_lock_irq(&x->wait.lock); |
2934 | if (!x->done) { |
2935 | DECLARE_WAITQUEUE(wait, current); |
2936 | |
2937 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
2938 | __add_wait_queue_tail(&x->wait, &wait); |
2939 | do { |
2940 | __set_current_state(TASK_UNINTERRUPTIBLE); |
2941 | spin_unlock_irq(&x->wait.lock); |
2942 | schedule(); |
2943 | spin_lock_irq(&x->wait.lock); |
2944 | } while (!x->done); |
2945 | __remove_wait_queue(&x->wait, &wait); |
2946 | } |
2947 | x->done--; |
2948 | spin_unlock_irq(&x->wait.lock); |
2949 | } |
2950 | EXPORT_SYMBOL(wait_for_completion); |
2951 | |
2952 | unsigned long fastcall __sched |
2953 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
2954 | { |
2955 | might_sleep(); |
2956 | |
2957 | spin_lock_irq(&x->wait.lock); |
2958 | if (!x->done) { |
2959 | DECLARE_WAITQUEUE(wait, current); |
2960 | |
2961 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
2962 | __add_wait_queue_tail(&x->wait, &wait); |
2963 | do { |
2964 | __set_current_state(TASK_UNINTERRUPTIBLE); |
2965 | spin_unlock_irq(&x->wait.lock); |
2966 | timeout = schedule_timeout(timeout); |
2967 | spin_lock_irq(&x->wait.lock); |
2968 | if (!timeout) { |
2969 | __remove_wait_queue(&x->wait, &wait); |
2970 | goto out; |
2971 | } |
2972 | } while (!x->done); |
2973 | __remove_wait_queue(&x->wait, &wait); |
2974 | } |
2975 | x->done--; |
2976 | out: |
2977 | spin_unlock_irq(&x->wait.lock); |
2978 | return timeout; |
2979 | } |
2980 | EXPORT_SYMBOL(wait_for_completion_timeout); |
2981 | |
2982 | int fastcall __sched wait_for_completion_interruptible(struct completion *x) |
2983 | { |
2984 | int ret = 0; |
2985 | |
2986 | might_sleep(); |
2987 | |
2988 | spin_lock_irq(&x->wait.lock); |
2989 | if (!x->done) { |
2990 | DECLARE_WAITQUEUE(wait, current); |
2991 | |
2992 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
2993 | __add_wait_queue_tail(&x->wait, &wait); |
2994 | do { |
2995 | if (signal_pending(current)) { |
2996 | ret = -ERESTARTSYS; |
2997 | __remove_wait_queue(&x->wait, &wait); |
2998 | goto out; |
2999 | } |
3000 | __set_current_state(TASK_INTERRUPTIBLE); |
3001 | spin_unlock_irq(&x->wait.lock); |
3002 | schedule(); |
3003 | spin_lock_irq(&x->wait.lock); |
3004 | } while (!x->done); |
3005 | __remove_wait_queue(&x->wait, &wait); |
3006 | } |
3007 | x->done--; |
3008 | out: |
3009 | spin_unlock_irq(&x->wait.lock); |
3010 | |
3011 | return ret; |
3012 | } |
3013 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
3014 | |
3015 | unsigned long fastcall __sched |
3016 | wait_for_completion_interruptible_timeout(struct completion *x, |
3017 | unsigned long timeout) |
3018 | { |
3019 | might_sleep(); |
3020 | |
3021 | spin_lock_irq(&x->wait.lock); |
3022 | if (!x->done) { |
3023 | DECLARE_WAITQUEUE(wait, current); |
3024 | |
3025 | wait.flags |= WQ_FLAG_EXCLUSIVE; |
3026 | __add_wait_queue_tail(&x->wait, &wait); |
3027 | do { |
3028 | if (signal_pending(current)) { |
3029 | timeout = -ERESTARTSYS; |
3030 | __remove_wait_queue(&x->wait, &wait); |
3031 | goto out; |
3032 | } |
3033 | __set_current_state(TASK_INTERRUPTIBLE); |
3034 | spin_unlock_irq(&x->wait.lock); |
3035 | timeout = schedule_timeout(timeout); |
3036 | spin_lock_irq(&x->wait.lock); |
3037 | if (!timeout) { |
3038 | __remove_wait_queue(&x->wait, &wait); |
3039 | goto out; |
3040 | } |
3041 | } while (!x->done); |
3042 | __remove_wait_queue(&x->wait, &wait); |
3043 | } |
3044 | x->done--; |
3045 | out: |
3046 | spin_unlock_irq(&x->wait.lock); |
3047 | return timeout; |
3048 | } |
3049 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
3050 | |
3051 | |
3052 | #define SLEEP_ON_VAR \ |
3053 | unsigned long flags; \ |
3054 | wait_queue_t wait; \ |
3055 | init_waitqueue_entry(&wait, current); |
3056 | |
3057 | #define SLEEP_ON_HEAD \ |
3058 | spin_lock_irqsave(&q->lock,flags); \ |
3059 | __add_wait_queue(q, &wait); \ |
3060 | spin_unlock(&q->lock); |
3061 | |
3062 | #define SLEEP_ON_TAIL \ |
3063 | spin_lock_irq(&q->lock); \ |
3064 | __remove_wait_queue(q, &wait); \ |
3065 | spin_unlock_irqrestore(&q->lock, flags); |
3066 | |
3067 | void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) |
3068 | { |
3069 | SLEEP_ON_VAR |
3070 | |
3071 | current->state = TASK_INTERRUPTIBLE; |
3072 | |
3073 | SLEEP_ON_HEAD |
3074 | schedule(); |
3075 | SLEEP_ON_TAIL |
3076 | } |
3077 | |
3078 | EXPORT_SYMBOL(interruptible_sleep_on); |
3079 | |
3080 | long fastcall __sched interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
3081 | { |
3082 | SLEEP_ON_VAR |
3083 | |
3084 | current->state = TASK_INTERRUPTIBLE; |
3085 | |
3086 | SLEEP_ON_HEAD |
3087 | timeout = schedule_timeout(timeout); |
3088 | SLEEP_ON_TAIL |
3089 | |
3090 | return timeout; |
3091 | } |
3092 | |
3093 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
3094 | |
3095 | void fastcall __sched sleep_on(wait_queue_head_t *q) |
3096 | { |
3097 | SLEEP_ON_VAR |
3098 | |
3099 | current->state = TASK_UNINTERRUPTIBLE; |
3100 | |
3101 | SLEEP_ON_HEAD |
3102 | schedule(); |
3103 | SLEEP_ON_TAIL |
3104 | } |
3105 | |
3106 | EXPORT_SYMBOL(sleep_on); |
3107 | |
3108 | long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
3109 | { |
3110 | SLEEP_ON_VAR |
3111 | |
3112 | current->state = TASK_UNINTERRUPTIBLE; |
3113 | |
3114 | SLEEP_ON_HEAD |
3115 | timeout = schedule_timeout(timeout); |
3116 | SLEEP_ON_TAIL |
3117 | |
3118 | return timeout; |
3119 | } |
3120 | |
3121 | EXPORT_SYMBOL(sleep_on_timeout); |
3122 | |
3123 | void set_user_nice(task_t *p, long nice) |
3124 | { |
3125 | unsigned long flags; |
3126 | runqueue_t *rq; |
3127 | int queued, old_prio, new_prio, delta; |
3128 | |
3129 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
3130 | return; |
3131 | /* |
3132 | * We have to be careful, if called from sys_setpriority(), |
3133 | * the task might be in the middle of scheduling on another CPU. |
3134 | */ |
3135 | rq = task_rq_lock(p, &flags); |
3136 | /* |
3137 | * The RT priorities are set via sched_setscheduler(), but we still |
3138 | * allow the 'normal' nice value to be set - but as expected |
3139 | * it wont have any effect on scheduling until the task is |
3140 | * not SCHED_NORMAL: |
3141 | */ |
3142 | if (rt_task(p)) { |
3143 | p->static_prio = NICE_TO_PRIO(nice); |
3144 | goto out_unlock; |
3145 | } |
3146 | if ((queued = task_queued(p))) { |
3147 | dequeue_task(p, rq); |
3148 | dec_prio_bias(rq, p->static_prio); |
3149 | } |
3150 | |
3151 | old_prio = p->prio; |
3152 | new_prio = NICE_TO_PRIO(nice); |
3153 | delta = new_prio - old_prio; |
3154 | p->static_prio = NICE_TO_PRIO(nice); |
3155 | p->prio += delta; |
3156 | |
3157 | if (queued) { |
3158 | enqueue_task(p, rq); |
3159 | inc_prio_bias(rq, p->static_prio); |
3160 | /* |
3161 | * If the task increased its priority or is running and |
3162 | * lowered its priority, then reschedule its CPU: |
3163 | */ |
3164 | if (delta < 0 || ((delta > 0 || batch_task(p)) && |
3165 | task_running(rq, p))) |
3166 | resched_task(rq->curr); |
3167 | } |
3168 | out_unlock: |
3169 | task_rq_unlock(rq, &flags); |
3170 | } |
3171 | |
3172 | EXPORT_SYMBOL(set_user_nice); |
3173 | |
3174 | /* |
3175 | * can_nice - check if a task can reduce its nice value |
3176 | * @p: task |
3177 | * @nice: nice value |
3178 | */ |
3179 | int can_nice(const task_t *p, const int nice) |
3180 | { |
3181 | /* convert nice value [19,-20] to rlimit style value [0,39] */ |
3182 | int nice_rlim = 19 - nice; |
3183 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
3184 | capable(CAP_SYS_NICE)); |
3185 | } |
3186 | |
3187 | #ifdef __ARCH_WANT_SYS_NICE |
3188 | |
3189 | /* |
3190 | * sys_nice - change the priority of the current process. |
3191 | * @increment: priority increment |
3192 | * |
3193 | * sys_setpriority is a more generic, but much slower function that |
3194 | * does similar things. |
3195 | */ |
3196 | asmlinkage long sys_nice(int increment) |
3197 | { |
3198 | int retval; |
3199 | long nice; |
3200 | |
3201 | /* |
3202 | * Setpriority might change our priority at the same moment. |
3203 | * We don't have to worry. Conceptually one call occurs first |
3204 | * and we have a single winner. |
3205 | */ |
3206 | if (increment < -40) |
3207 | increment = -40; |
3208 | if (increment > 40) |
3209 | increment = 40; |
3210 | |
3211 | nice = PRIO_TO_NICE(current->static_prio) + increment; |
3212 | if (nice < -20) |
3213 | nice = -20; |
3214 | if (nice > 19) |
3215 | nice = 19; |
3216 | |
3217 | if (increment < 0 && !can_nice(current, nice)) |
3218 | return -EPERM; |
3219 | |
3220 | retval = security_task_setnice(current, nice); |
3221 | if (retval) |
3222 | return retval; |
3223 | |
3224 | set_user_nice(current, nice); |
3225 | return 0; |
3226 | } |
3227 | |
3228 | #endif |
3229 | |
3230 | /** |
3231 | * task_prio - return the priority value of a given task. |
3232 | * @p: the task in question. |
3233 | * |
3234 | * This is the priority value as seen by users in /proc. |
3235 | * RT tasks are offset by -200. Normal tasks are centered |
3236 | * around 0, value goes from -16 to +15. |
3237 | */ |
3238 | int task_prio(const task_t *p) |
3239 | { |
3240 | return p->prio - MAX_RT_PRIO; |
3241 | } |
3242 | |
3243 | /** |
3244 | * task_nice - return the nice value of a given task. |
3245 | * @p: the task in question. |
3246 | */ |
3247 | int task_nice(const task_t *p) |
3248 | { |
3249 | return TASK_NICE(p); |
3250 | } |
3251 | |
3252 | /* |
3253 | * The only users of task_nice are binfmt_elf and binfmt_elf32. |
3254 | * binfmt_elf is no longer modular, but binfmt_elf32 still is. |
3255 | * Therefore, task_nice is needed if there is a compat_mode. |
3256 | */ |
3257 | #ifdef CONFIG_COMPAT |
3258 | EXPORT_SYMBOL_GPL(task_nice); |
3259 | #endif |
3260 | |
3261 | /** |
3262 | * idle_cpu - is a given cpu idle currently? |
3263 | * @cpu: the processor in question. |
3264 | */ |
3265 | int idle_cpu(int cpu) |
3266 | { |
3267 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; |
3268 | } |
3269 | |
3270 | EXPORT_SYMBOL_GPL(idle_cpu); |
3271 | |
3272 | /** |
3273 | * idle_task - return the idle task for a given cpu. |
3274 | * @cpu: the processor in question. |
3275 | */ |
3276 | task_t *idle_task(int cpu) |
3277 | { |
3278 | return cpu_rq(cpu)->idle; |
3279 | } |
3280 | |
3281 | /** |
3282 | * find_process_by_pid - find a process with a matching PID value. |
3283 | * @pid: the pid in question. |
3284 | */ |
3285 | static inline task_t *find_process_by_pid(pid_t pid) |
3286 | { |
3287 | return pid ? find_task_by_pid(pid) : current; |
3288 | } |
3289 | |
3290 | /* Actually do priority change: must hold rq lock. */ |
3291 | static void __setscheduler(struct task_struct *p, int policy, int prio) |
3292 | { |
3293 | BUG_ON(task_queued(p)); |
3294 | p->policy = policy; |
3295 | p->rt_priority = prio; |
3296 | if (SCHED_RT(policy)) |
3297 | p->prio = MAX_USER_RT_PRIO-1 - p->rt_priority; |
3298 | else |
3299 | p->prio = p->static_prio; |
3300 | } |
3301 | |
3302 | /** |
3303 | * sched_setscheduler - change the scheduling policy and/or RT priority of |
3304 | * a thread. |
3305 | * @p: the task in question. |
3306 | * @policy: new policy. |
3307 | * @param: structure containing the new RT priority. |
3308 | */ |
3309 | int sched_setscheduler(struct task_struct *p, int policy, struct sched_param *param) |
3310 | { |
3311 | int retval; |
3312 | int queued, oldprio, oldpolicy = -1; |
3313 | unsigned long flags; |
3314 | runqueue_t *rq; |
3315 | |
3316 | recheck: |
3317 | /* double check policy once rq lock held */ |
3318 | if (policy < 0) |
3319 | policy = oldpolicy = p->policy; |
3320 | else if (!SCHED_RANGE(policy)) |
3321 | return -EINVAL; |
3322 | /* |
3323 | * Valid priorities for SCHED_FIFO and SCHED_RR are |
3324 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL is 0. |
3325 | */ |
3326 | if (param->sched_priority < 0 || |
3327 | param->sched_priority > MAX_USER_RT_PRIO-1) |
3328 | return -EINVAL; |
3329 | if ((!SCHED_RT(policy)) != (param->sched_priority == 0)) |
3330 | return -EINVAL; |
3331 | |
3332 | if (SCHED_RT(policy) && |
3333 | param->sched_priority > p->signal->rlim[RLIMIT_RTPRIO].rlim_cur && |
3334 | !capable(CAP_SYS_NICE)) |
3335 | return -EPERM; |
3336 | if ((current->euid != p->euid) && (current->euid != p->uid) && |
3337 | !capable(CAP_SYS_NICE)) |
3338 | return -EPERM; |
3339 | |
3340 | if (!(p->mm) && policy == SCHED_BATCH) |
3341 | /* |
3342 | * Don't allow kernel threads to be SCHED_BATCH. |
3343 | */ |
3344 | return -EINVAL; |
3345 | |
3346 | retval = security_task_setscheduler(p, policy, param); |
3347 | if (retval) |
3348 | return retval; |
3349 | /* |
3350 | * To be able to change p->policy safely, the apropriate |
3351 | * runqueue lock must be held. |
3352 | */ |
3353 | rq = task_rq_lock(p, &flags); |
3354 | /* recheck policy now with rq lock held */ |
3355 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
3356 | policy = oldpolicy = -1; |
3357 | task_rq_unlock(rq, &flags); |
3358 | goto recheck; |
3359 | } |
3360 | if ((queued = task_queued(p))) |
3361 | deactivate_task(p, rq); |
3362 | oldprio = p->prio; |
3363 | __setscheduler(p, policy, param->sched_priority); |
3364 | if (queued) { |
3365 | __activate_task(p, rq); |
3366 | /* |
3367 | * Reschedule if we are currently running on this runqueue and |
3368 | * our priority decreased, or if we are not currently running on |
3369 | * this runqueue and our priority is higher than the current's |
3370 | */ |
3371 | if (task_running(rq, p)) { |
3372 | if (p->prio > oldprio) |
3373 | resched_task(rq->curr); |
3374 | } else |
3375 | preempt(p, rq); |
3376 | } |
3377 | task_rq_unlock(rq, &flags); |
3378 | return 0; |
3379 | } |
3380 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
3381 | |
3382 | static int do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
3383 | { |
3384 | int retval; |
3385 | struct sched_param lparam; |
3386 | struct task_struct *p; |
3387 | |
3388 | if (!param || pid < 0) |
3389 | return -EINVAL; |
3390 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
3391 | return -EFAULT; |
3392 | read_lock_irq(&tasklist_lock); |
3393 | p = find_process_by_pid(pid); |
3394 | if (!p) { |
3395 | read_unlock_irq(&tasklist_lock); |
3396 | return -ESRCH; |
3397 | } |
3398 | retval = sched_setscheduler(p, policy, &lparam); |
3399 | read_unlock_irq(&tasklist_lock); |
3400 | return retval; |
3401 | } |
3402 | |
3403 | /** |
3404 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
3405 | * @pid: the pid in question. |
3406 | * @policy: new policy. |
3407 | * @param: structure containing the new RT priority. |
3408 | */ |
3409 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, |
3410 | struct sched_param __user *param) |
3411 | { |
3412 | return do_sched_setscheduler(pid, policy, param); |
3413 | } |
3414 | |
3415 | /** |
3416 | * sys_sched_setparam - set/change the RT priority of a thread |
3417 | * @pid: the pid in question. |
3418 | * @param: structure containing the new RT priority. |
3419 | */ |
3420 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) |
3421 | { |
3422 | return do_sched_setscheduler(pid, -1, param); |
3423 | } |
3424 | |
3425 | /** |
3426 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
3427 | * @pid: the pid in question. |
3428 | */ |
3429 | asmlinkage long sys_sched_getscheduler(pid_t pid) |
3430 | { |
3431 | int retval = -EINVAL; |
3432 | task_t *p; |
3433 | |
3434 | if (pid < 0) |
3435 | goto out_nounlock; |
3436 | |
3437 | retval = -ESRCH; |
3438 | read_lock(&tasklist_lock); |
3439 | p = find_process_by_pid(pid); |
3440 | if (p) { |
3441 | retval = security_task_getscheduler(p); |
3442 | if (!retval) |
3443 | retval = p->policy; |
3444 | } |
3445 | read_unlock(&tasklist_lock); |
3446 | |
3447 | out_nounlock: |
3448 | return retval; |
3449 | } |
3450 | |
3451 | /** |
3452 | * sys_sched_getscheduler - get the RT priority of a thread |
3453 | * @pid: the pid in question. |
3454 | * @param: structure containing the RT priority. |
3455 | */ |
3456 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) |
3457 | { |
3458 | struct sched_param lp; |
3459 | int retval = -EINVAL; |
3460 | task_t *p; |
3461 | |
3462 | if (!param || pid < 0) |
3463 | goto out_nounlock; |
3464 | |
3465 | read_lock(&tasklist_lock); |
3466 | p = find_process_by_pid(pid); |
3467 | retval = -ESRCH; |
3468 | if (!p) |
3469 | goto out_unlock; |
3470 | |
3471 | retval = security_task_getscheduler(p); |
3472 | if (retval) |
3473 | goto out_unlock; |
3474 | |
3475 | lp.sched_priority = p->rt_priority; |
3476 | read_unlock(&tasklist_lock); |
3477 | |
3478 | /* |
3479 | * This one might sleep, we cannot do it with a spinlock held ... |
3480 | */ |
3481 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
3482 | |
3483 | out_nounlock: |
3484 | return retval; |
3485 | |
3486 | out_unlock: |
3487 | read_unlock(&tasklist_lock); |
3488 | return retval; |
3489 | } |
3490 | |
3491 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) |
3492 | { |
3493 | task_t *p; |
3494 | int retval; |
3495 | cpumask_t cpus_allowed; |
3496 | |
3497 | lock_cpu_hotplug(); |
3498 | read_lock(&tasklist_lock); |
3499 | |
3500 | p = find_process_by_pid(pid); |
3501 | if (!p) { |
3502 | read_unlock(&tasklist_lock); |
3503 | unlock_cpu_hotplug(); |
3504 | return -ESRCH; |
3505 | } |
3506 | |
3507 | /* |
3508 | * It is not safe to call set_cpus_allowed with the |
3509 | * tasklist_lock held. We will bump the task_struct's |
3510 | * usage count and then drop tasklist_lock. |
3511 | */ |
3512 | get_task_struct(p); |
3513 | read_unlock(&tasklist_lock); |
3514 | |
3515 | retval = -EPERM; |
3516 | if ((current->euid != p->euid) && (current->euid != p->uid) && |
3517 | !capable(CAP_SYS_NICE)) |
3518 | goto out_unlock; |
3519 | |
3520 | cpus_allowed = cpuset_cpus_allowed(p); |
3521 | cpus_and(new_mask, new_mask, cpus_allowed); |
3522 | retval = set_cpus_allowed(p, new_mask); |
3523 | |
3524 | out_unlock: |
3525 | put_task_struct(p); |
3526 | unlock_cpu_hotplug(); |
3527 | return retval; |
3528 | } |
3529 | |
3530 | static inline int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
3531 | cpumask_t *new_mask) |
3532 | { |
3533 | if (len < sizeof(cpumask_t)) { |
3534 | memset(new_mask, 0, sizeof(cpumask_t)); |
3535 | } else if (len > sizeof(cpumask_t)) { |
3536 | len = sizeof(cpumask_t); |
3537 | } |
3538 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
3539 | } |
3540 | |
3541 | /** |
3542 | * sys_sched_setaffinity - set the cpu affinity of a process |
3543 | * @pid: pid of the process |
3544 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
3545 | * @user_mask_ptr: user-space pointer to the new cpu mask |
3546 | */ |
3547 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, |
3548 | unsigned long __user *user_mask_ptr) |
3549 | { |
3550 | cpumask_t new_mask; |
3551 | int retval; |
3552 | |
3553 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); |
3554 | if (retval) |
3555 | return retval; |
3556 | |
3557 | return sched_setaffinity(pid, new_mask); |
3558 | } |
3559 | |
3560 | /* |
3561 | * Represents all cpu's present in the system |
3562 | * In systems capable of hotplug, this map could dynamically grow |
3563 | * as new cpu's are detected in the system via any platform specific |
3564 | * method, such as ACPI for e.g. |
3565 | */ |
3566 | |
3567 | cpumask_t cpu_present_map; |
3568 | EXPORT_SYMBOL(cpu_present_map); |
3569 | |
3570 | #ifndef CONFIG_SMP |
3571 | cpumask_t cpu_online_map = CPU_MASK_ALL; |
3572 | cpumask_t cpu_possible_map = CPU_MASK_ALL; |
3573 | #endif |
3574 | |
3575 | long sched_getaffinity(pid_t pid, cpumask_t *mask) |
3576 | { |
3577 | int retval; |
3578 | task_t *p; |
3579 | |
3580 | lock_cpu_hotplug(); |
3581 | read_lock(&tasklist_lock); |
3582 | |
3583 | retval = -ESRCH; |
3584 | p = find_process_by_pid(pid); |
3585 | if (!p) |
3586 | goto out_unlock; |
3587 | |
3588 | retval = 0; |
3589 | cpus_and(*mask, p->cpus_allowed, cpu_possible_map); |
3590 | |
3591 | out_unlock: |
3592 | read_unlock(&tasklist_lock); |
3593 | unlock_cpu_hotplug(); |
3594 | if (retval) |
3595 | return retval; |
3596 | |
3597 | return 0; |
3598 | } |
3599 | |
3600 | /** |
3601 | * sys_sched_getaffinity - get the cpu affinity of a process |
3602 | * @pid: pid of the process |
3603 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
3604 | * @user_mask_ptr: user-space pointer to hold the current cpu mask |
3605 | */ |
3606 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, |
3607 | unsigned long __user *user_mask_ptr) |
3608 | { |
3609 | int ret; |
3610 | cpumask_t mask; |
3611 | |
3612 | if (len < sizeof(cpumask_t)) |
3613 | return -EINVAL; |
3614 | |
3615 | ret = sched_getaffinity(pid, &mask); |
3616 | if (ret < 0) |
3617 | return ret; |
3618 | |
3619 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) |
3620 | return -EFAULT; |
3621 | |
3622 | return sizeof(cpumask_t); |
3623 | } |
3624 | |
3625 | /** |
3626 | * sys_sched_yield - yield the current processor to other threads. |
3627 | * This function yields the current CPU by dropping the priority of current |
3628 | * to the lowest priority and setting the PF_YIELDED flag. |
3629 | */ |
3630 | asmlinkage long sys_sched_yield(void) |
3631 | { |
3632 | int newprio; |
3633 | runqueue_t *rq = this_rq_lock(); |
3634 | |
3635 | newprio = current->prio; |
3636 | schedstat_inc(rq, yld_cnt); |
3637 | current->slice = slice(current); |
3638 | current->time_slice = rr_interval(current); |
3639 | if (likely(!rt_task(current) && !batch_task(current))) { |
3640 | current->flags |= PF_YIELDED; |
3641 | newprio = MAX_PRIO - 2; |
3642 | } |
3643 | |
3644 | if (newprio != current->prio) { |
3645 | dequeue_task(current, rq); |
3646 | current->prio = newprio; |
3647 | enqueue_task(current, rq); |
3648 | } else |
3649 | requeue_task(current, rq); |
3650 | |
3651 | /* |
3652 | * Since we are going to call schedule() anyway, there's |
3653 | * no need to preempt or enable interrupts: |
3654 | */ |
3655 | __release(rq->lock); |
3656 | _raw_spin_unlock(&rq->lock); |
3657 | preempt_enable_no_resched(); |
3658 | |
3659 | schedule(); |
3660 | |
3661 | return 0; |
3662 | } |
3663 | |
3664 | static inline void __cond_resched(void) |
3665 | { |
3666 | do { |
3667 | add_preempt_count(PREEMPT_ACTIVE); |
3668 | schedule(); |
3669 | sub_preempt_count(PREEMPT_ACTIVE); |
3670 | } while (need_resched()); |
3671 | } |
3672 | |
3673 | int __sched cond_resched(void) |
3674 | { |
3675 | if (need_resched()) { |
3676 | __cond_resched(); |
3677 | return 1; |
3678 | } |
3679 | return 0; |
3680 | } |
3681 | |
3682 | EXPORT_SYMBOL(cond_resched); |
3683 | |
3684 | /* |
3685 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, |
3686 | * call schedule, and on return reacquire the lock. |
3687 | * |
3688 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
3689 | * operations here to prevent schedule() from being called twice (once via |
3690 | * spin_unlock(), once by hand). |
3691 | */ |
3692 | int cond_resched_lock(spinlock_t * lock) |
3693 | { |
3694 | int ret = 0; |
3695 | |
3696 | if (need_lockbreak(lock)) { |
3697 | spin_unlock(lock); |
3698 | cpu_relax(); |
3699 | ret = 1; |
3700 | spin_lock(lock); |
3701 | } |
3702 | if (need_resched()) { |
3703 | _raw_spin_unlock(lock); |
3704 | preempt_enable_no_resched(); |
3705 | __cond_resched(); |
3706 | ret = 1; |
3707 | spin_lock(lock); |
3708 | } |
3709 | return ret; |
3710 | } |
3711 | |
3712 | EXPORT_SYMBOL(cond_resched_lock); |
3713 | |
3714 | int __sched cond_resched_softirq(void) |
3715 | { |
3716 | BUG_ON(!in_softirq()); |
3717 | |
3718 | if (need_resched()) { |
3719 | __local_bh_enable(); |
3720 | __cond_resched(); |
3721 | local_bh_disable(); |
3722 | return 1; |
3723 | } |
3724 | return 0; |
3725 | } |
3726 | |
3727 | EXPORT_SYMBOL(cond_resched_softirq); |
3728 | |
3729 | |
3730 | /** |
3731 | * yield - yield the current processor to other threads. |
3732 | * |
3733 | * this is a shortcut for kernel-space yielding - it marks the |
3734 | * thread runnable and calls sys_sched_yield(). |
3735 | */ |
3736 | void __sched yield(void) |
3737 | { |
3738 | set_current_state(TASK_RUNNING); |
3739 | sys_sched_yield(); |
3740 | } |
3741 | |
3742 | EXPORT_SYMBOL(yield); |
3743 | |
3744 | /* |
3745 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
3746 | * that process accounting knows that this is a task in IO wait state. |
3747 | * |
3748 | * But don't do that if it is a deliberate, throttling IO wait (this task |
3749 | * has set its backing_dev_info: the queue against which it should throttle) |
3750 | */ |
3751 | void __sched io_schedule(void) |
3752 | { |
3753 | struct runqueue *rq = &per_cpu(runqueues, _smp_processor_id()); |
3754 | |
3755 | atomic_inc(&rq->nr_iowait); |
3756 | schedule(); |
3757 | atomic_dec(&rq->nr_iowait); |
3758 | } |
3759 | |
3760 | EXPORT_SYMBOL(io_schedule); |
3761 | |
3762 | long __sched io_schedule_timeout(long timeout) |
3763 | { |
3764 | struct runqueue *rq = &per_cpu(runqueues, _smp_processor_id()); |
3765 | long ret; |
3766 | |
3767 | atomic_inc(&rq->nr_iowait); |
3768 | ret = schedule_timeout(timeout); |
3769 | atomic_dec(&rq->nr_iowait); |
3770 | return ret; |
3771 | } |
3772 | |
3773 | /** |
3774 | * sys_sched_get_priority_max - return maximum RT priority. |
3775 | * @policy: scheduling class. |
3776 | * |
3777 | * this syscall returns the maximum rt_priority that can be used |
3778 | * by a given scheduling class. |
3779 | */ |
3780 | asmlinkage long sys_sched_get_priority_max(int policy) |
3781 | { |
3782 | int ret = -EINVAL; |
3783 | |
3784 | switch (policy) { |
3785 | case SCHED_FIFO: |
3786 | case SCHED_RR: |
3787 | ret = MAX_USER_RT_PRIO-1; |
3788 | break; |
3789 | case SCHED_NORMAL: |
3790 | case SCHED_BATCH: |
3791 | ret = 0; |
3792 | break; |
3793 | } |
3794 | return ret; |
3795 | } |
3796 | |
3797 | /** |
3798 | * sys_sched_get_priority_min - return minimum RT priority. |
3799 | * @policy: scheduling class. |
3800 | * |
3801 | * this syscall returns the minimum rt_priority that can be used |
3802 | * by a given scheduling class. |
3803 | */ |
3804 | asmlinkage long sys_sched_get_priority_min(int policy) |
3805 | { |
3806 | int ret = -EINVAL; |
3807 | |
3808 | switch (policy) { |
3809 | case SCHED_FIFO: |
3810 | case SCHED_RR: |
3811 | ret = 1; |
3812 | break; |
3813 | case SCHED_NORMAL: |
3814 | case SCHED_BATCH: |
3815 | ret = 0; |
3816 | } |
3817 | return ret; |
3818 | } |
3819 | |
3820 | /** |
3821 | * sys_sched_rr_get_interval - return the default timeslice of a process. |
3822 | * @pid: pid of the process. |
3823 | * @interval: userspace pointer to the timeslice value. |
3824 | * |
3825 | * this syscall writes the default timeslice value of a given process |
3826 | * into the user-space timespec buffer. A value of '0' means infinity. |
3827 | */ |
3828 | asmlinkage |
3829 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) |
3830 | { |
3831 | int retval = -EINVAL; |
3832 | struct timespec t; |
3833 | task_t *p; |
3834 | |
3835 | if (pid < 0) |
3836 | goto out_nounlock; |
3837 | |
3838 | retval = -ESRCH; |
3839 | read_lock(&tasklist_lock); |
3840 | p = find_process_by_pid(pid); |
3841 | if (!p) |
3842 | goto out_unlock; |
3843 | |
3844 | retval = security_task_getscheduler(p); |
3845 | if (retval) |
3846 | goto out_unlock; |
3847 | |
3848 | jiffies_to_timespec(p->policy & SCHED_FIFO ? |
3849 | 0 : slice(p), &t); |
3850 | read_unlock(&tasklist_lock); |
3851 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
3852 | out_nounlock: |
3853 | return retval; |
3854 | out_unlock: |
3855 | read_unlock(&tasklist_lock); |
3856 | return retval; |
3857 | } |
3858 | |
3859 | static inline struct task_struct *eldest_child(struct task_struct *p) |
3860 | { |
3861 | if (list_empty(&p->children)) return NULL; |
3862 | return list_entry(p->children.next,struct task_struct,sibling); |
3863 | } |
3864 | |
3865 | static inline struct task_struct *older_sibling(struct task_struct *p) |
3866 | { |
3867 | if (p->sibling.prev==&p->parent->children) return NULL; |
3868 | return list_entry(p->sibling.prev,struct task_struct,sibling); |
3869 | } |
3870 | |
3871 | static inline struct task_struct *younger_sibling(struct task_struct *p) |
3872 | { |
3873 | if (p->sibling.next==&p->parent->children) return NULL; |
3874 | return list_entry(p->sibling.next,struct task_struct,sibling); |
3875 | } |
3876 | |
3877 | static inline void show_task(task_t * p) |
3878 | { |
3879 | task_t *relative; |
3880 | unsigned state; |
3881 | unsigned long free = 0; |
3882 | static const char *stat_nam[] = { "R", "S", "D", "T", "t", "Z", "X" }; |
3883 | |
3884 | printk("%-13.13s ", p->comm); |
3885 | state = p->state ? __ffs(p->state) + 1 : 0; |
3886 | if (state < ARRAY_SIZE(stat_nam)) |
3887 | printk(stat_nam[state]); |
3888 | else |
3889 | printk("?"); |
3890 | #if (BITS_PER_LONG == 32) |
3891 | if (state == TASK_RUNNING) |
3892 | printk(" running "); |
3893 | else |
3894 | printk(" %08lX ", thread_saved_pc(p)); |
3895 | #else |
3896 | if (state == TASK_RUNNING) |
3897 | printk(" running task "); |
3898 | else |
3899 | printk(" %016lx ", thread_saved_pc(p)); |
3900 | #endif |
3901 | #ifdef CONFIG_DEBUG_STACK_USAGE |
3902 | { |
3903 | unsigned long * n = (unsigned long *) (p->thread_info+1); |
3904 | while (!*n) |
3905 | n++; |
3906 | free = (unsigned long) n - (unsigned long)(p->thread_info+1); |
3907 | } |
3908 | #endif |
3909 | printk("%5lu %5d %6d ", free, p->pid, p->parent->pid); |
3910 | if ((relative = eldest_child(p))) |
3911 | printk("%5d ", relative->pid); |
3912 | else |
3913 | printk(" "); |
3914 | if ((relative = younger_sibling(p))) |
3915 | printk("%7d", relative->pid); |
3916 | else |
3917 | printk(" "); |
3918 | if ((relative = older_sibling(p))) |
3919 | printk(" %5d", relative->pid); |
3920 | else |
3921 | printk(" "); |
3922 | if (!p->mm) |
3923 | printk(" (L-TLB)\n"); |
3924 | else |
3925 | printk(" (NOTLB)\n"); |
3926 | |
3927 | if (state != TASK_RUNNING) |
3928 | show_stack(p, NULL); |
3929 | } |
3930 | |
3931 | void show_state(void) |
3932 | { |
3933 | task_t *g, *p; |
3934 | |
3935 | #if (BITS_PER_LONG == 32) |
3936 | printk("\n" |
3937 | " sibling\n"); |
3938 | printk(" task PC pid father child younger older\n"); |
3939 | #else |
3940 | printk("\n" |
3941 | " sibling\n"); |
3942 | printk(" task PC pid father child younger older\n"); |
3943 | #endif |
3944 | read_lock(&tasklist_lock); |
3945 | do_each_thread(g, p) { |
3946 | /* |
3947 | * reset the NMI-timeout, listing all files on a slow |
3948 | * console might take alot of time: |
3949 | */ |
3950 | touch_nmi_watchdog(); |
3951 | show_task(p); |
3952 | } while_each_thread(g, p); |
3953 | |
3954 | read_unlock(&tasklist_lock); |
3955 | } |
3956 | |
3957 | void __devinit init_idle(task_t *idle, int cpu) |
3958 | { |
3959 | runqueue_t *rq = cpu_rq(cpu); |
3960 | unsigned long flags; |
3961 | |
3962 | idle->prio = MAX_PRIO; |
3963 | idle->state = TASK_RUNNING; |
3964 | idle->cpus_allowed = cpumask_of_cpu(cpu); |
3965 | set_task_cpu(idle, cpu); |
3966 | |
3967 | spin_lock_irqsave(&rq->lock, flags); |
3968 | rq->curr = rq->idle = idle; |
3969 | set_tsk_need_resched(idle); |
3970 | spin_unlock_irqrestore(&rq->lock, flags); |
3971 | |
3972 | /* Set the preempt count _outside_ the spinlocks! */ |
3973 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) |
3974 | idle->thread_info->preempt_count = (idle->lock_depth >= 0); |
3975 | #else |
3976 | idle->thread_info->preempt_count = 0; |
3977 | #endif |
3978 | } |
3979 | |
3980 | /* |
3981 | * In a system that switches off the HZ timer nohz_cpu_mask |
3982 | * indicates which cpus entered this state. This is used |
3983 | * in the rcu update to wait only for active cpus. For system |
3984 | * which do not switch off the HZ timer nohz_cpu_mask should |
3985 | * always be CPU_MASK_NONE. |
3986 | */ |
3987 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; |
3988 | |
3989 | #ifdef CONFIG_SMP |
3990 | /* |
3991 | * This is how migration works: |
3992 | * |
3993 | * 1) we queue a migration_req_t structure in the source CPU's |
3994 | * runqueue and wake up that CPU's migration thread. |
3995 | * 2) we down() the locked semaphore => thread blocks. |
3996 | * 3) migration thread wakes up (implicitly it forces the migrated |
3997 | * thread off the CPU) |
3998 | * 4) it gets the migration request and checks whether the migrated |
3999 | * task is still in the wrong runqueue. |
4000 | * 5) if it's in the wrong runqueue then the migration thread removes |
4001 | * it and puts it into the right queue. |
4002 | * 6) migration thread up()s the semaphore. |
4003 | * 7) we wake up and the migration is done. |
4004 | */ |
4005 | |
4006 | /* |
4007 | * Change a given task's CPU affinity. Migrate the thread to a |
4008 | * proper CPU and schedule it away if the CPU it's executing on |
4009 | * is removed from the allowed bitmask. |
4010 | * |
4011 | * NOTE: the caller must have a valid reference to the task, the |
4012 | * task must not exit() & deallocate itself prematurely. The |
4013 | * call is not atomic; no spinlocks may be held. |
4014 | */ |
4015 | int set_cpus_allowed(task_t *p, cpumask_t new_mask) |
4016 | { |
4017 | unsigned long flags; |
4018 | int ret = 0; |
4019 | migration_req_t req; |
4020 | runqueue_t *rq; |
4021 | |
4022 | rq = task_rq_lock(p, &flags); |
4023 | if (!cpus_intersects(new_mask, cpu_online_map)) { |
4024 | ret = -EINVAL; |
4025 | goto out; |
4026 | } |
4027 | |
4028 | p->cpus_allowed = new_mask; |
4029 | /* Can the task run on the task's current CPU? If so, we're done */ |
4030 | if (cpu_isset(task_cpu(p), new_mask)) |
4031 | goto out; |
4032 | |
4033 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { |
4034 | /* Need help from migration thread: drop lock and wait. */ |
4035 | task_rq_unlock(rq, &flags); |
4036 | wake_up_process(rq->migration_thread); |
4037 | wait_for_completion(&req.done); |
4038 | tlb_migrate_finish(p->mm); |
4039 | return 0; |
4040 | } |
4041 | out: |
4042 | task_rq_unlock(rq, &flags); |
4043 | return ret; |
4044 | } |
4045 | |
4046 | EXPORT_SYMBOL_GPL(set_cpus_allowed); |
4047 | |
4048 | /* |
4049 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
4050 | * this because either it can't run here any more (set_cpus_allowed() |
4051 | * away from this CPU, or CPU going down), or because we're |
4052 | * attempting to rebalance this task on exec (sched_exec). |
4053 | * |
4054 | * So we race with normal scheduler movements, but that's OK, as long |
4055 | * as the task is no longer on this CPU. |
4056 | */ |
4057 | static void __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
4058 | { |
4059 | runqueue_t *rq_dest, *rq_src; |
4060 | |
4061 | if (unlikely(cpu_is_offline(dest_cpu))) |
4062 | return; |
4063 | |
4064 | rq_src = cpu_rq(src_cpu); |
4065 | rq_dest = cpu_rq(dest_cpu); |
4066 | |
4067 | double_rq_lock(rq_src, rq_dest); |
4068 | /* Already moved. */ |
4069 | if (task_cpu(p) != src_cpu) |
4070 | goto out; |
4071 | /* Affinity changed (again). */ |
4072 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) |
4073 | goto out; |
4074 | |
4075 | set_task_cpu(p, dest_cpu); |
4076 | if (task_queued(p)) { |
4077 | /* |
4078 | * Sync timestamp with rq_dest's before activating. |
4079 | * The same thing could be achieved by doing this step |
4080 | * afterwards, and pretending it was a local activate. |
4081 | * This way is cleaner and logically correct. |
4082 | */ |
4083 | p->timestamp = p->timestamp - rq_src->timestamp_last_tick |
4084 | + rq_dest->timestamp_last_tick; |
4085 | deactivate_task(p, rq_src); |
4086 | activate_task(p, rq_dest, 0); |
4087 | preempt(p, rq_dest); |
4088 | } |
4089 | |
4090 | out: |
4091 | double_rq_unlock(rq_src, rq_dest); |
4092 | } |
4093 | |
4094 | /* |
4095 | * migration_thread - this is a highprio system thread that performs |
4096 | * thread migration by bumping thread off CPU then 'pushing' onto |
4097 | * another runqueue. |
4098 | */ |
4099 | static int migration_thread(void * data) |
4100 | { |
4101 | runqueue_t *rq; |
4102 | int cpu = (long)data; |
4103 | |
4104 | rq = cpu_rq(cpu); |
4105 | BUG_ON(rq->migration_thread != current); |
4106 | |
4107 | set_current_state(TASK_INTERRUPTIBLE); |
4108 | while (!kthread_should_stop()) { |
4109 | struct list_head *head; |
4110 | migration_req_t *req; |
4111 | |
4112 | if (current->flags & PF_FREEZE) |
4113 | refrigerator(PF_FREEZE); |
4114 | |
4115 | spin_lock_irq(&rq->lock); |
4116 | |
4117 | if (cpu_is_offline(cpu)) { |
4118 | spin_unlock_irq(&rq->lock); |
4119 | goto wait_to_die; |
4120 | } |
4121 | |
4122 | if (rq->active_balance) { |
4123 | active_load_balance(rq, cpu); |
4124 | rq->active_balance = 0; |
4125 | } |
4126 | |
4127 | head = &rq->migration_queue; |
4128 | |
4129 | if (list_empty(head)) { |
4130 | spin_unlock_irq(&rq->lock); |
4131 | schedule(); |
4132 | set_current_state(TASK_INTERRUPTIBLE); |
4133 | continue; |
4134 | } |
4135 | req = list_entry(head->next, migration_req_t, list); |
4136 | list_del_init(head->next); |
4137 | |
4138 | if (req->type == REQ_MOVE_TASK) { |
4139 | spin_unlock(&rq->lock); |
4140 | __migrate_task(req->task, cpu, req->dest_cpu); |
4141 | local_irq_enable(); |
4142 | } else if (req->type == REQ_SET_DOMAIN) { |
4143 | rq->sd = req->sd; |
4144 | spin_unlock_irq(&rq->lock); |
4145 | } else { |
4146 | spin_unlock_irq(&rq->lock); |
4147 | WARN_ON(1); |
4148 | } |
4149 | |
4150 | complete(&req->done); |
4151 | } |
4152 | __set_current_state(TASK_RUNNING); |
4153 | return 0; |
4154 | |
4155 | wait_to_die: |
4156 | /* Wait for kthread_stop */ |
4157 | set_current_state(TASK_INTERRUPTIBLE); |
4158 | while (!kthread_should_stop()) { |
4159 | schedule(); |
4160 | set_current_state(TASK_INTERRUPTIBLE); |
4161 | } |
4162 | __set_current_state(TASK_RUNNING); |
4163 | return 0; |
4164 | } |
4165 | |
4166 | #ifdef CONFIG_HOTPLUG_CPU |
4167 | /* Figure out where task on dead CPU should go, use force if neccessary. */ |
4168 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *tsk) |
4169 | { |
4170 | int dest_cpu; |
4171 | cpumask_t mask; |
4172 | |
4173 | /* On same node? */ |
4174 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); |
4175 | cpus_and(mask, mask, tsk->cpus_allowed); |
4176 | dest_cpu = any_online_cpu(mask); |
4177 | |
4178 | /* On any allowed CPU? */ |
4179 | if (dest_cpu == NR_CPUS) |
4180 | dest_cpu = any_online_cpu(tsk->cpus_allowed); |
4181 | |
4182 | /* No more Mr. Nice Guy. */ |
4183 | if (dest_cpu == NR_CPUS) { |
4184 | cpus_setall(tsk->cpus_allowed); |
4185 | dest_cpu = any_online_cpu(tsk->cpus_allowed); |
4186 | |
4187 | /* |
4188 | * Don't tell them about moving exiting tasks or |
4189 | * kernel threads (both mm NULL), since they never |
4190 | * leave kernel. |
4191 | */ |
4192 | if (tsk->mm && printk_ratelimit()) |
4193 | printk(KERN_INFO "process %d (%s) no " |
4194 | "longer affine to cpu%d\n", |
4195 | tsk->pid, tsk->comm, dead_cpu); |
4196 | } |
4197 | __migrate_task(tsk, dead_cpu, dest_cpu); |
4198 | } |
4199 | |
4200 | /* |
4201 | * While a dead CPU has no uninterruptible tasks queued at this point, |
4202 | * it might still have a nonzero ->nr_uninterruptible counter, because |
4203 | * for performance reasons the counter is not stricly tracking tasks to |
4204 | * their home CPUs. So we just add the counter to another CPU's counter, |
4205 | * to keep the global sum constant after CPU-down: |
4206 | */ |
4207 | static void migrate_nr_uninterruptible(runqueue_t *rq_src) |
4208 | { |
4209 | runqueue_t *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); |
4210 | unsigned long flags; |
4211 | |
4212 | local_irq_save(flags); |
4213 | double_rq_lock(rq_src, rq_dest); |
4214 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
4215 | rq_src->nr_uninterruptible = 0; |
4216 | double_rq_unlock(rq_src, rq_dest); |
4217 | local_irq_restore(flags); |
4218 | } |
4219 | |
4220 | /* Run through task list and migrate tasks from the dead cpu. */ |
4221 | static void migrate_live_tasks(int src_cpu) |
4222 | { |
4223 | struct task_struct *tsk, *t; |
4224 | |
4225 | write_lock_irq(&tasklist_lock); |
4226 | |
4227 | do_each_thread(t, tsk) { |
4228 | if (tsk == current) |
4229 | continue; |
4230 | |
4231 | if (task_cpu(tsk) == src_cpu) |
4232 | move_task_off_dead_cpu(src_cpu, tsk); |
4233 | } while_each_thread(t, tsk); |
4234 | |
4235 | write_unlock_irq(&tasklist_lock); |
4236 | } |
4237 | |
4238 | /* Schedules idle task to be the next runnable task on current CPU. |
4239 | * It does so by boosting its priority to highest possible and adding it to |
4240 | * the _front_ of runqueue. Used by CPU offline code. |
4241 | */ |
4242 | void sched_idle_next(void) |
4243 | { |
4244 | int cpu = smp_processor_id(); |
4245 | runqueue_t *rq = this_rq(); |
4246 | struct task_struct *p = rq->idle; |
4247 | unsigned long flags; |
4248 | |
4249 | /* cpu has to be offline */ |
4250 | BUG_ON(cpu_online(cpu)); |
4251 | |
4252 | /* Strictly not necessary since rest of the CPUs are stopped by now |
4253 | * and interrupts disabled on current cpu. |
4254 | */ |
4255 | spin_lock_irqsave(&rq->lock, flags); |
4256 | |
4257 | __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); |
4258 | /* Add idle task to _front_ of it's priority queue */ |
4259 | __activate_idle_task(p, rq); |
4260 | |
4261 | spin_unlock_irqrestore(&rq->lock, flags); |
4262 | } |
4263 | |
4264 | /* Ensures that the idle task is using init_mm right before its cpu goes |
4265 | * offline. |
4266 | */ |
4267 | void idle_task_exit(void) |
4268 | { |
4269 | struct mm_struct *mm = current->active_mm; |
4270 | |
4271 | BUG_ON(cpu_online(smp_processor_id())); |
4272 | |
4273 | if (mm != &init_mm) |
4274 | switch_mm(mm, &init_mm, current); |
4275 | mmdrop(mm); |
4276 | } |
4277 | |
4278 | static void migrate_dead(unsigned int dead_cpu, task_t *tsk) |
4279 | { |
4280 | struct runqueue *rq = cpu_rq(dead_cpu); |
4281 | |
4282 | /* Must be exiting, otherwise would be on tasklist. */ |
4283 | BUG_ON(tsk->exit_state != EXIT_ZOMBIE && tsk->exit_state != EXIT_DEAD); |
4284 | |
4285 | /* Cannot have done final schedule yet: would have vanished. */ |
4286 | BUG_ON(tsk->flags & PF_DEAD); |
4287 | |
4288 | get_task_struct(tsk); |
4289 | |
4290 | /* |
4291 | * Drop lock around migration; if someone else moves it, |
4292 | * that's OK. No task can be added to this CPU, so iteration is |
4293 | * fine. |
4294 | */ |
4295 | spin_unlock_irq(&rq->lock); |
4296 | move_task_off_dead_cpu(dead_cpu, tsk); |
4297 | spin_lock_irq(&rq->lock); |
4298 | |
4299 | put_task_struct(tsk); |
4300 | } |
4301 | |
4302 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ |
4303 | static void migrate_dead_tasks(unsigned int dead_cpu) |
4304 | { |
4305 | unsigned arr, i; |
4306 | struct runqueue *rq = cpu_rq(dead_cpu); |
4307 | |
4308 | for (arr = 0; arr < 2; arr++) { |
4309 | for (i = 0; i < MAX_PRIO; i++) { |
4310 | struct list_head *list = &rq->queue[i]; |
4311 | while (!list_empty(list)) |
4312 | migrate_dead(dead_cpu, |
4313 | list_entry(list->next, task_t, |
4314 | run_list)); |
4315 | } |
4316 | } |
4317 | } |
4318 | #endif /* CONFIG_HOTPLUG_CPU */ |
4319 | |
4320 | /* |
4321 | * migration_call - callback that gets triggered when a CPU is added. |
4322 | * Here we can start up the necessary migration thread for the new CPU. |
4323 | */ |
4324 | static int migration_call(struct notifier_block *nfb, unsigned long action, |
4325 | void *hcpu) |
4326 | { |
4327 | int cpu = (long)hcpu; |
4328 | struct task_struct *p; |
4329 | struct runqueue *rq; |
4330 | unsigned long flags; |
4331 | |
4332 | switch (action) { |
4333 | case CPU_UP_PREPARE: |
4334 | p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); |
4335 | if (IS_ERR(p)) |
4336 | return NOTIFY_BAD; |
4337 | p->flags |= PF_NOFREEZE; |
4338 | kthread_bind(p, cpu); |
4339 | /* Must be high prio: stop_machine expects to yield to it. */ |
4340 | rq = task_rq_lock(p, &flags); |
4341 | __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); |
4342 | task_rq_unlock(rq, &flags); |
4343 | cpu_rq(cpu)->migration_thread = p; |
4344 | break; |
4345 | case CPU_ONLINE: |
4346 | /* Strictly unneccessary, as first user will wake it. */ |
4347 | wake_up_process(cpu_rq(cpu)->migration_thread); |
4348 | break; |
4349 | #ifdef CONFIG_HOTPLUG_CPU |
4350 | case CPU_UP_CANCELED: |
4351 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
4352 | kthread_bind(cpu_rq(cpu)->migration_thread,smp_processor_id()); |
4353 | kthread_stop(cpu_rq(cpu)->migration_thread); |
4354 | cpu_rq(cpu)->migration_thread = NULL; |
4355 | break; |
4356 | case CPU_DEAD: |
4357 | migrate_live_tasks(cpu); |
4358 | rq = cpu_rq(cpu); |
4359 | kthread_stop(rq->migration_thread); |
4360 | rq->migration_thread = NULL; |
4361 | /* Idle task back to normal (off runqueue, low prio) */ |
4362 | rq = task_rq_lock(rq->idle, &flags); |
4363 | deactivate_task(rq->idle, rq); |
4364 | rq->idle->static_prio = MAX_PRIO; |
4365 | __setscheduler(rq->idle, SCHED_NORMAL, 0); |
4366 | migrate_dead_tasks(cpu); |
4367 | task_rq_unlock(rq, &flags); |
4368 | migrate_nr_uninterruptible(rq); |
4369 | BUG_ON(rq->nr_running != 0); |
4370 | |
4371 | /* No need to migrate the tasks: it was best-effort if |
4372 | * they didn't do lock_cpu_hotplug(). Just wake up |
4373 | * the requestors. */ |
4374 | spin_lock_irq(&rq->lock); |
4375 | while (!list_empty(&rq->migration_queue)) { |
4376 | migration_req_t *req; |
4377 | req = list_entry(rq->migration_queue.next, |
4378 | migration_req_t, list); |
4379 | BUG_ON(req->type != REQ_MOVE_TASK); |
4380 | list_del_init(&req->list); |
4381 | complete(&req->done); |
4382 | } |
4383 | spin_unlock_irq(&rq->lock); |
4384 | break; |
4385 | #endif |
4386 | } |
4387 | return NOTIFY_OK; |
4388 | } |
4389 | |
4390 | /* Register at highest priority so that task migration (migrate_all_tasks) |
4391 | * happens before everything else. |
4392 | */ |
4393 | static struct notifier_block __devinitdata migration_notifier = { |
4394 | .notifier_call = migration_call, |
4395 | .priority = 10 |
4396 | }; |
4397 | |
4398 | int __init migration_init(void) |
4399 | { |
4400 | void *cpu = (void *)(long)smp_processor_id(); |
4401 | /* Start one for boot CPU. */ |
4402 | migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
4403 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
4404 | register_cpu_notifier(&migration_notifier); |
4405 | return 0; |
4406 | } |
4407 | #endif |
4408 | |
4409 | #ifdef CONFIG_SMP |
4410 | #define SCHED_DOMAIN_DEBUG |
4411 | #ifdef SCHED_DOMAIN_DEBUG |
4412 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
4413 | { |
4414 | int level = 0; |
4415 | |
4416 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
4417 | |
4418 | do { |
4419 | int i; |
4420 | char str[NR_CPUS]; |
4421 | struct sched_group *group = sd->groups; |
4422 | cpumask_t groupmask; |
4423 | |
4424 | cpumask_scnprintf(str, NR_CPUS, sd->span); |
4425 | cpus_clear(groupmask); |
4426 | |
4427 | printk(KERN_DEBUG); |
4428 | for (i = 0; i < level + 1; i++) |
4429 | printk(" "); |
4430 | printk("domain %d: ", level); |
4431 | |
4432 | if (!(sd->flags & SD_LOAD_BALANCE)) { |
4433 | printk("does not load-balance\n"); |
4434 | if (sd->parent) |
4435 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain has parent"); |
4436 | break; |
4437 | } |
4438 | |
4439 | printk("span %s\n", str); |
4440 | |
4441 | if (!cpu_isset(cpu, sd->span)) |
4442 | printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu); |
4443 | if (!cpu_isset(cpu, group->cpumask)) |
4444 | printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu); |
4445 | |
4446 | printk(KERN_DEBUG); |
4447 | for (i = 0; i < level + 2; i++) |
4448 | printk(" "); |
4449 | printk("groups:"); |
4450 | do { |
4451 | if (!group) { |
4452 | printk("\n"); |
4453 | printk(KERN_ERR "ERROR: group is NULL\n"); |
4454 | break; |
4455 | } |
4456 | |
4457 | if (!group->cpu_power) { |
4458 | printk("\n"); |
4459 | printk(KERN_ERR "ERROR: domain->cpu_power not set\n"); |
4460 | } |
4461 | |
4462 | if (!cpus_weight(group->cpumask)) { |
4463 | printk("\n"); |
4464 | printk(KERN_ERR "ERROR: empty group\n"); |
4465 | } |
4466 | |
4467 | if (cpus_intersects(groupmask, group->cpumask)) { |
4468 | printk("\n"); |
4469 | printk(KERN_ERR "ERROR: repeated CPUs\n"); |
4470 | } |
4471 | |
4472 | cpus_or(groupmask, groupmask, group->cpumask); |
4473 | |
4474 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); |
4475 | printk(" %s", str); |
4476 | |
4477 | group = group->next; |
4478 | } while (group != sd->groups); |
4479 | printk("\n"); |
4480 | |
4481 | if (!cpus_equal(sd->span, groupmask)) |
4482 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
4483 | |
4484 | level++; |
4485 | sd = sd->parent; |
4486 | |
4487 | if (sd) { |
4488 | if (!cpus_subset(groupmask, sd->span)) |
4489 | printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n"); |
4490 | } |
4491 | |
4492 | } while (sd); |
4493 | } |
4494 | #else |
4495 | #define sched_domain_debug(sd, cpu) {} |
4496 | #endif |
4497 | |
4498 | /* |
4499 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
4500 | * hold the hotplug lock. |
4501 | */ |
4502 | void __devinit cpu_attach_domain(struct sched_domain *sd, int cpu) |
4503 | { |
4504 | migration_req_t req; |
4505 | unsigned long flags; |
4506 | runqueue_t *rq = cpu_rq(cpu); |
4507 | int local = 1; |
4508 | |
4509 | sched_domain_debug(sd, cpu); |
4510 | |
4511 | spin_lock_irqsave(&rq->lock, flags); |
4512 | |
4513 | if (cpu == smp_processor_id() || !cpu_online(cpu)) { |
4514 | rq->sd = sd; |
4515 | } else { |
4516 | init_completion(&req.done); |
4517 | req.type = REQ_SET_DOMAIN; |
4518 | req.sd = sd; |
4519 | list_add(&req.list, &rq->migration_queue); |
4520 | local = 0; |
4521 | } |
4522 | |
4523 | spin_unlock_irqrestore(&rq->lock, flags); |
4524 | |
4525 | if (!local) { |
4526 | wake_up_process(rq->migration_thread); |
4527 | wait_for_completion(&req.done); |
4528 | } |
4529 | } |
4530 | |
4531 | /* cpus with isolated domains */ |
4532 | cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE; |
4533 | |
4534 | /* Setup the mask of cpus configured for isolated domains */ |
4535 | static int __init isolated_cpu_setup(char *str) |
4536 | { |
4537 | int ints[NR_CPUS], i; |
4538 | |
4539 | str = get_options(str, ARRAY_SIZE(ints), ints); |
4540 | cpus_clear(cpu_isolated_map); |
4541 | for (i = 1; i <= ints[0]; i++) |
4542 | if (ints[i] < NR_CPUS) |
4543 | cpu_set(ints[i], cpu_isolated_map); |
4544 | return 1; |
4545 | } |
4546 | |
4547 | __setup ("isolcpus=", isolated_cpu_setup); |
4548 | |
4549 | /* |
4550 | * init_sched_build_groups takes an array of groups, the cpumask we wish |
4551 | * to span, and a pointer to a function which identifies what group a CPU |
4552 | * belongs to. The return value of group_fn must be a valid index into the |
4553 | * groups[] array, and must be >= 0 and < NR_CPUS (due to the fact that we |
4554 | * keep track of groups covered with a cpumask_t). |
4555 | * |
4556 | * init_sched_build_groups will build a circular linked list of the groups |
4557 | * covered by the given span, and will set each group's ->cpumask correctly, |
4558 | * and ->cpu_power to 0. |
4559 | */ |
4560 | void __devinit init_sched_build_groups(struct sched_group groups[], |
4561 | cpumask_t span, int (*group_fn)(int cpu)) |
4562 | { |
4563 | struct sched_group *first = NULL, *last = NULL; |
4564 | cpumask_t covered = CPU_MASK_NONE; |
4565 | int i; |
4566 | |
4567 | for_each_cpu_mask(i, span) { |
4568 | int group = group_fn(i); |
4569 | struct sched_group *sg = &groups[group]; |
4570 | int j; |
4571 | |
4572 | if (cpu_isset(i, covered)) |
4573 | continue; |
4574 | |
4575 | sg->cpumask = CPU_MASK_NONE; |
4576 | sg->cpu_power = 0; |
4577 | |
4578 | for_each_cpu_mask(j, span) { |
4579 | if (group_fn(j) != group) |
4580 | continue; |
4581 | |
4582 | cpu_set(j, covered); |
4583 | cpu_set(j, sg->cpumask); |
4584 | } |
4585 | if (!first) |
4586 | first = sg; |
4587 | if (last) |
4588 | last->next = sg; |
4589 | last = sg; |
4590 | } |
4591 | last->next = first; |
4592 | } |
4593 | |
4594 | |
4595 | #ifdef ARCH_HAS_SCHED_DOMAIN |
4596 | extern void __devinit arch_init_sched_domains(void); |
4597 | extern void __devinit arch_destroy_sched_domains(void); |
4598 | #else |
4599 | #ifdef CONFIG_SCHED_SMT |
4600 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); |
4601 | static struct sched_group sched_group_cpus[NR_CPUS]; |
4602 | static int __devinit cpu_to_cpu_group(int cpu) |
4603 | { |
4604 | return cpu; |
4605 | } |
4606 | #endif |
4607 | |
4608 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
4609 | static struct sched_group sched_group_phys[NR_CPUS]; |
4610 | static int __devinit cpu_to_phys_group(int cpu) |
4611 | { |
4612 | #ifdef CONFIG_SCHED_SMT |
4613 | return first_cpu(cpu_sibling_map[cpu]); |
4614 | #else |
4615 | return cpu; |
4616 | #endif |
4617 | } |
4618 | |
4619 | #ifdef CONFIG_NUMA |
4620 | |
4621 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
4622 | static struct sched_group sched_group_nodes[MAX_NUMNODES]; |
4623 | static int __devinit cpu_to_node_group(int cpu) |
4624 | { |
4625 | return cpu_to_node(cpu); |
4626 | } |
4627 | #endif |
4628 | |
4629 | #if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA) |
4630 | /* |
4631 | * The domains setup code relies on siblings not spanning |
4632 | * multiple nodes. Make sure the architecture has a proper |
4633 | * siblings map: |
4634 | */ |
4635 | static void check_sibling_maps(void) |
4636 | { |
4637 | int i, j; |
4638 | |
4639 | for_each_online_cpu(i) { |
4640 | for_each_cpu_mask(j, cpu_sibling_map[i]) { |
4641 | if (cpu_to_node(i) != cpu_to_node(j)) { |
4642 | printk(KERN_INFO "warning: CPU %d siblings map " |
4643 | "to different node - isolating " |
4644 | "them.\n", i); |
4645 | cpu_sibling_map[i] = cpumask_of_cpu(i); |
4646 | break; |
4647 | } |
4648 | } |
4649 | } |
4650 | } |
4651 | #endif |
4652 | |
4653 | /* |
4654 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
4655 | */ |
4656 | static void __devinit arch_init_sched_domains(void) |
4657 | { |
4658 | int i; |
4659 | cpumask_t cpu_default_map; |
4660 | |
4661 | #if defined(CONFIG_SCHED_SMT) && defined(CONFIG_NUMA) |
4662 | check_sibling_maps(); |
4663 | #endif |
4664 | /* |
4665 | * Setup mask for cpus without special case scheduling requirements. |
4666 | * For now this just excludes isolated cpus, but could be used to |
4667 | * exclude other special cases in the future. |
4668 | */ |
4669 | cpus_complement(cpu_default_map, cpu_isolated_map); |
4670 | cpus_and(cpu_default_map, cpu_default_map, cpu_online_map); |
4671 | |
4672 | /* |
4673 | * Set up domains. Isolated domains just stay on the dummy domain. |
4674 | */ |
4675 | for_each_cpu_mask(i, cpu_default_map) { |
4676 | int group; |
4677 | struct sched_domain *sd = NULL, *p; |
4678 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); |
4679 | |
4680 | cpus_and(nodemask, nodemask, cpu_default_map); |
4681 | |
4682 | #ifdef CONFIG_NUMA |
4683 | sd = &per_cpu(node_domains, i); |
4684 | group = cpu_to_node_group(i); |
4685 | *sd = SD_NODE_INIT; |
4686 | sd->span = cpu_default_map; |
4687 | sd->groups = &sched_group_nodes[group]; |
4688 | #endif |
4689 | |
4690 | p = sd; |
4691 | sd = &per_cpu(phys_domains, i); |
4692 | group = cpu_to_phys_group(i); |
4693 | *sd = SD_CPU_INIT; |
4694 | sd->span = nodemask; |
4695 | sd->parent = p; |
4696 | sd->groups = &sched_group_phys[group]; |
4697 | |
4698 | #ifdef CONFIG_SCHED_SMT |
4699 | p = sd; |
4700 | sd = &per_cpu(cpu_domains, i); |
4701 | group = cpu_to_cpu_group(i); |
4702 | *sd = SD_SIBLING_INIT; |
4703 | sd->span = cpu_sibling_map[i]; |
4704 | cpus_and(sd->span, sd->span, cpu_default_map); |
4705 | sd->parent = p; |
4706 | sd->groups = &sched_group_cpus[group]; |
4707 | #endif |
4708 | } |
4709 | |
4710 | #ifdef CONFIG_SCHED_SMT |
4711 | /* Set up CPU (sibling) groups */ |
4712 | for_each_online_cpu(i) { |
4713 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
4714 | cpus_and(this_sibling_map, this_sibling_map, cpu_default_map); |
4715 | if (i != first_cpu(this_sibling_map)) |
4716 | continue; |
4717 | |
4718 | init_sched_build_groups(sched_group_cpus, this_sibling_map, |
4719 | &cpu_to_cpu_group); |
4720 | } |
4721 | #endif |
4722 | |
4723 | /* Set up physical groups */ |
4724 | for (i = 0; i < MAX_NUMNODES; i++) { |
4725 | cpumask_t nodemask = node_to_cpumask(i); |
4726 | |
4727 | cpus_and(nodemask, nodemask, cpu_default_map); |
4728 | if (cpus_empty(nodemask)) |
4729 | continue; |
4730 | |
4731 | init_sched_build_groups(sched_group_phys, nodemask, |
4732 | &cpu_to_phys_group); |
4733 | } |
4734 | |
4735 | #ifdef CONFIG_NUMA |
4736 | /* Set up node groups */ |
4737 | init_sched_build_groups(sched_group_nodes, cpu_default_map, |
4738 | &cpu_to_node_group); |
4739 | #endif |
4740 | |
4741 | /* Calculate CPU power for physical packages and nodes */ |
4742 | for_each_cpu_mask(i, cpu_default_map) { |
4743 | int power; |
4744 | struct sched_domain *sd; |
4745 | #ifdef CONFIG_SCHED_SMT |
4746 | sd = &per_cpu(cpu_domains, i); |
4747 | power = SCHED_LOAD_SCALE; |
4748 | sd->groups->cpu_power = power; |
4749 | #endif |
4750 | |
4751 | sd = &per_cpu(phys_domains, i); |
4752 | power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE * |
4753 | (cpus_weight(sd->groups->cpumask)-1) / 10; |
4754 | sd->groups->cpu_power = power; |
4755 | |
4756 | #ifdef CONFIG_NUMA |
4757 | if (i == first_cpu(sd->groups->cpumask)) { |
4758 | /* Only add "power" once for each physical package. */ |
4759 | sd = &per_cpu(node_domains, i); |
4760 | sd->groups->cpu_power += power; |
4761 | } |
4762 | #endif |
4763 | } |
4764 | |
4765 | /* Attach the domains */ |
4766 | for_each_online_cpu(i) { |
4767 | struct sched_domain *sd; |
4768 | #ifdef CONFIG_SCHED_SMT |
4769 | sd = &per_cpu(cpu_domains, i); |
4770 | #else |
4771 | sd = &per_cpu(phys_domains, i); |
4772 | #endif |
4773 | cpu_attach_domain(sd, i); |
4774 | } |
4775 | } |
4776 | |
4777 | #ifdef CONFIG_HOTPLUG_CPU |
4778 | static void __devinit arch_destroy_sched_domains(void) |
4779 | { |
4780 | /* Do nothing: everything is statically allocated. */ |
4781 | } |
4782 | #endif |
4783 | |
4784 | #endif /* ARCH_HAS_SCHED_DOMAIN */ |
4785 | |
4786 | /* |
4787 | * Initial dummy domain for early boot and for hotplug cpu. Being static, |
4788 | * it is initialized to zero, so all balancing flags are cleared which is |
4789 | * what we want. |
4790 | */ |
4791 | static struct sched_domain sched_domain_dummy; |
4792 | |
4793 | #ifdef CONFIG_HOTPLUG_CPU |
4794 | /* |
4795 | * Force a reinitialization of the sched domains hierarchy. The domains |
4796 | * and groups cannot be updated in place without racing with the balancing |
4797 | * code, so we temporarily attach all running cpus to a "dummy" domain |
4798 | * which will prevent rebalancing while the sched domains are recalculated. |
4799 | */ |
4800 | static int update_sched_domains(struct notifier_block *nfb, |
4801 | unsigned long action, void *hcpu) |
4802 | { |
4803 | int i; |
4804 | |
4805 | switch (action) { |
4806 | case CPU_UP_PREPARE: |
4807 | case CPU_DOWN_PREPARE: |
4808 | for_each_online_cpu(i) |
4809 | cpu_attach_domain(&sched_domain_dummy, i); |
4810 | arch_destroy_sched_domains(); |
4811 | return NOTIFY_OK; |
4812 | |
4813 | case CPU_UP_CANCELED: |
4814 | case CPU_DOWN_FAILED: |
4815 | case CPU_ONLINE: |
4816 | case CPU_DEAD: |
4817 | /* |
4818 | * Fall through and re-initialise the domains. |
4819 | */ |
4820 | break; |
4821 | default: |
4822 | return NOTIFY_DONE; |
4823 | } |
4824 | |
4825 | /* The hotplug lock is already held by cpu_up/cpu_down */ |
4826 | arch_init_sched_domains(); |
4827 | |
4828 | return NOTIFY_OK; |
4829 | } |
4830 | #endif |
4831 | |
4832 | void __init sched_init_smp(void) |
4833 | { |
4834 | lock_cpu_hotplug(); |
4835 | arch_init_sched_domains(); |
4836 | unlock_cpu_hotplug(); |
4837 | /* XXX: Theoretical race here - CPU may be hotplugged now */ |
4838 | hotcpu_notifier(update_sched_domains, 0); |
4839 | } |
4840 | #else |
4841 | void __init sched_init_smp(void) |
4842 | { |
4843 | } |
4844 | #endif /* CONFIG_SMP */ |
4845 | |
4846 | int in_sched_functions(unsigned long addr) |
4847 | { |
4848 | /* Linker adds these: start and end of __sched functions */ |
4849 | extern char __sched_text_start[], __sched_text_end[]; |
4850 | return in_lock_functions(addr) || |
4851 | (addr >= (unsigned long)__sched_text_start |
4852 | && addr < (unsigned long)__sched_text_end); |
4853 | } |
4854 | |
4855 | void __init sched_init(void) |
4856 | { |
4857 | runqueue_t *rq; |
4858 | int i, j; |
4859 | |
4860 | for (i = 0; i < NR_CPUS; i++) { |
4861 | |
4862 | rq = cpu_rq(i); |
4863 | spin_lock_init(&rq->lock); |
4864 | rq->cache_ticks = 0; |
4865 | rq->preempted = 0; |
4866 | |
4867 | #ifdef CONFIG_SMP |
4868 | rq->sd = &sched_domain_dummy; |
4869 | rq->cpu_load = 0; |
4870 | rq->active_balance = 0; |
4871 | rq->push_cpu = 0; |
4872 | rq->migration_thread = NULL; |
4873 | INIT_LIST_HEAD(&rq->migration_queue); |
4874 | #endif |
4875 | atomic_set(&rq->nr_iowait, 0); |
4876 | for (j = 0; j < MAX_PRIO; j++) |
4877 | INIT_LIST_HEAD(&rq->queue[j]); |
4878 | memset(rq->bitmap, 0, BITS_TO_LONGS(MAX_PRIO)*sizeof(long)); |
4879 | /* |
4880 | * delimiter for bitsearch |
4881 | */ |
4882 | __set_bit(MAX_PRIO, rq->bitmap); |
4883 | } |
4884 | |
4885 | /* |
4886 | * The boot idle thread does lazy MMU switching as well: |
4887 | */ |
4888 | atomic_inc(&init_mm.mm_count); |
4889 | enter_lazy_tlb(&init_mm, current); |
4890 | |
4891 | /* |
4892 | * Make us the idle thread. Technically, schedule() should not be |
4893 | * called from this thread, however somewhere below it might be, |
4894 | * but because we are the idle thread, we just pick up running again |
4895 | * when this runqueue becomes "idle". |
4896 | */ |
4897 | init_idle(current, smp_processor_id()); |
4898 | } |
4899 | |
4900 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4901 | void __might_sleep(char *file, int line) |
4902 | { |
4903 | #if defined(in_atomic) |
4904 | static unsigned long prev_jiffy; /* ratelimiting */ |
4905 | |
4906 | if ((in_atomic() || irqs_disabled()) && |
4907 | system_state == SYSTEM_RUNNING && !oops_in_progress) { |
4908 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
4909 | return; |
4910 | prev_jiffy = jiffies; |
4911 | printk(KERN_ERR "Debug: sleeping function called from invalid" |
4912 | " context at %s:%d\n", file, line); |
4913 | printk("in_atomic():%d, irqs_disabled():%d\n", |
4914 | in_atomic(), irqs_disabled()); |
4915 | dump_stack(); |
4916 | } |
4917 | #endif |
4918 | } |
4919 | EXPORT_SYMBOL(__might_sleep); |
4920 | #endif |
4921 | |
4922 | #ifdef CONFIG_MAGIC_SYSRQ |
4923 | void normalize_rt_tasks(void) |
4924 | { |
4925 | struct task_struct *p; |
4926 | unsigned long flags; |
4927 | runqueue_t *rq; |
4928 | int queued; |
4929 | |
4930 | read_lock_irq(&tasklist_lock); |
4931 | for_each_process (p) { |
4932 | if (!rt_task(p)) |
4933 | continue; |
4934 | |
4935 | rq = task_rq_lock(p, &flags); |
4936 | |
4937 | if ((queued = task_queued(p))) |
4938 | deactivate_task(p, task_rq(p)); |
4939 | __setscheduler(p, SCHED_NORMAL, 0); |
4940 | if (queued) { |
4941 | __activate_task(p, task_rq(p)); |
4942 | resched_task(rq->curr); |
4943 | } |
4944 | |
4945 | task_rq_unlock(rq, &flags); |
4946 | } |
4947 | read_unlock_irq(&tasklist_lock); |
4948 | } |
4949 | |
4950 | #endif /* CONFIG_MAGIC_SYSRQ */ |