Commit | Line | Data |
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1da177e4 LT |
1 | /* |
2 | * kernel/sched.c | |
3 | * | |
4 | * Kernel scheduler and related syscalls | |
5 | * | |
6 | * Copyright (C) 1991-2002 Linus Torvalds | |
7 | * | |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and | |
9 | * make semaphores SMP safe | |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff | |
11 | * by Andrea Arcangeli | |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: | |
13 | * hybrid priority-list and round-robin design with | |
14 | * an array-switch method of distributing timeslices | |
15 | * and per-CPU runqueues. Cleanups and useful suggestions | |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. | |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. | |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin | |
19 | */ | |
20 | ||
21 | #include <linux/mm.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/nmi.h> | |
24 | #include <linux/init.h> | |
25 | #include <asm/uaccess.h> | |
26 | #include <linux/highmem.h> | |
27 | #include <linux/smp_lock.h> | |
28 | #include <asm/mmu_context.h> | |
29 | #include <linux/interrupt.h> | |
c59ede7b | 30 | #include <linux/capability.h> |
1da177e4 LT |
31 | #include <linux/completion.h> |
32 | #include <linux/kernel_stat.h> | |
33 | #include <linux/security.h> | |
34 | #include <linux/notifier.h> | |
35 | #include <linux/profile.h> | |
36 | #include <linux/suspend.h> | |
198e2f18 | 37 | #include <linux/vmalloc.h> |
1da177e4 LT |
38 | #include <linux/blkdev.h> |
39 | #include <linux/delay.h> | |
40 | #include <linux/smp.h> | |
41 | #include <linux/threads.h> | |
42 | #include <linux/timer.h> | |
43 | #include <linux/rcupdate.h> | |
44 | #include <linux/cpu.h> | |
45 | #include <linux/cpuset.h> | |
46 | #include <linux/percpu.h> | |
47 | #include <linux/kthread.h> | |
48 | #include <linux/seq_file.h> | |
49 | #include <linux/syscalls.h> | |
50 | #include <linux/times.h> | |
51 | #include <linux/acct.h> | |
c6fd91f0 | 52 | #include <linux/kprobes.h> |
1da177e4 LT |
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 JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) | |
80 | ||
81 | /* | |
82 | * These are the 'tuning knobs' of the scheduler: | |
83 | * | |
84 | * Minimum timeslice is 5 msecs (or 1 jiffy, whichever is larger), | |
85 | * default timeslice is 100 msecs, maximum timeslice is 800 msecs. | |
86 | * Timeslices get refilled after they expire. | |
87 | */ | |
88 | #define MIN_TIMESLICE max(5 * HZ / 1000, 1) | |
89 | #define DEF_TIMESLICE (100 * HZ / 1000) | |
90 | #define ON_RUNQUEUE_WEIGHT 30 | |
91 | #define CHILD_PENALTY 95 | |
92 | #define PARENT_PENALTY 100 | |
93 | #define EXIT_WEIGHT 3 | |
94 | #define PRIO_BONUS_RATIO 25 | |
95 | #define MAX_BONUS (MAX_USER_PRIO * PRIO_BONUS_RATIO / 100) | |
96 | #define INTERACTIVE_DELTA 2 | |
97 | #define MAX_SLEEP_AVG (DEF_TIMESLICE * MAX_BONUS) | |
98 | #define STARVATION_LIMIT (MAX_SLEEP_AVG) | |
99 | #define NS_MAX_SLEEP_AVG (JIFFIES_TO_NS(MAX_SLEEP_AVG)) | |
100 | ||
101 | /* | |
102 | * If a task is 'interactive' then we reinsert it in the active | |
103 | * array after it has expired its current timeslice. (it will not | |
104 | * continue to run immediately, it will still roundrobin with | |
105 | * other interactive tasks.) | |
106 | * | |
107 | * This part scales the interactivity limit depending on niceness. | |
108 | * | |
109 | * We scale it linearly, offset by the INTERACTIVE_DELTA delta. | |
110 | * Here are a few examples of different nice levels: | |
111 | * | |
112 | * TASK_INTERACTIVE(-20): [1,1,1,1,1,1,1,1,1,0,0] | |
113 | * TASK_INTERACTIVE(-10): [1,1,1,1,1,1,1,0,0,0,0] | |
114 | * TASK_INTERACTIVE( 0): [1,1,1,1,0,0,0,0,0,0,0] | |
115 | * TASK_INTERACTIVE( 10): [1,1,0,0,0,0,0,0,0,0,0] | |
116 | * TASK_INTERACTIVE( 19): [0,0,0,0,0,0,0,0,0,0,0] | |
117 | * | |
118 | * (the X axis represents the possible -5 ... 0 ... +5 dynamic | |
119 | * priority range a task can explore, a value of '1' means the | |
120 | * task is rated interactive.) | |
121 | * | |
122 | * Ie. nice +19 tasks can never get 'interactive' enough to be | |
123 | * reinserted into the active array. And only heavily CPU-hog nice -20 | |
124 | * tasks will be expired. Default nice 0 tasks are somewhere between, | |
125 | * it takes some effort for them to get interactive, but it's not | |
126 | * too hard. | |
127 | */ | |
128 | ||
129 | #define CURRENT_BONUS(p) \ | |
130 | (NS_TO_JIFFIES((p)->sleep_avg) * MAX_BONUS / \ | |
131 | MAX_SLEEP_AVG) | |
132 | ||
133 | #define GRANULARITY (10 * HZ / 1000 ? : 1) | |
134 | ||
135 | #ifdef CONFIG_SMP | |
136 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ | |
137 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1)) * \ | |
138 | num_online_cpus()) | |
139 | #else | |
140 | #define TIMESLICE_GRANULARITY(p) (GRANULARITY * \ | |
141 | (1 << (((MAX_BONUS - CURRENT_BONUS(p)) ? : 1) - 1))) | |
142 | #endif | |
143 | ||
144 | #define SCALE(v1,v1_max,v2_max) \ | |
145 | (v1) * (v2_max) / (v1_max) | |
146 | ||
147 | #define DELTA(p) \ | |
013d3868 MA |
148 | (SCALE(TASK_NICE(p) + 20, 40, MAX_BONUS) - 20 * MAX_BONUS / 40 + \ |
149 | INTERACTIVE_DELTA) | |
1da177e4 LT |
150 | |
151 | #define TASK_INTERACTIVE(p) \ | |
152 | ((p)->prio <= (p)->static_prio - DELTA(p)) | |
153 | ||
154 | #define INTERACTIVE_SLEEP(p) \ | |
155 | (JIFFIES_TO_NS(MAX_SLEEP_AVG * \ | |
156 | (MAX_BONUS / 2 + DELTA((p)) + 1) / MAX_BONUS - 1)) | |
157 | ||
158 | #define TASK_PREEMPTS_CURR(p, rq) \ | |
159 | ((p)->prio < (rq)->curr->prio) | |
160 | ||
161 | /* | |
162 | * task_timeslice() scales user-nice values [ -20 ... 0 ... 19 ] | |
163 | * to time slice values: [800ms ... 100ms ... 5ms] | |
164 | * | |
165 | * The higher a thread's priority, the bigger timeslices | |
166 | * it gets during one round of execution. But even the lowest | |
167 | * priority thread gets MIN_TIMESLICE worth of execution time. | |
168 | */ | |
169 | ||
170 | #define SCALE_PRIO(x, prio) \ | |
171 | max(x * (MAX_PRIO - prio) / (MAX_USER_PRIO/2), MIN_TIMESLICE) | |
172 | ||
48c08d3f | 173 | static unsigned int task_timeslice(task_t *p) |
1da177e4 LT |
174 | { |
175 | if (p->static_prio < NICE_TO_PRIO(0)) | |
176 | return SCALE_PRIO(DEF_TIMESLICE*4, p->static_prio); | |
177 | else | |
178 | return SCALE_PRIO(DEF_TIMESLICE, p->static_prio); | |
179 | } | |
180 | #define task_hot(p, now, sd) ((long long) ((now) - (p)->last_ran) \ | |
181 | < (long long) (sd)->cache_hot_time) | |
182 | ||
183 | /* | |
184 | * These are the runqueue data structures: | |
185 | */ | |
186 | ||
1da177e4 LT |
187 | typedef struct runqueue runqueue_t; |
188 | ||
189 | struct prio_array { | |
190 | unsigned int nr_active; | |
d444886e | 191 | DECLARE_BITMAP(bitmap, MAX_PRIO+1); /* include 1 bit for delimiter */ |
1da177e4 LT |
192 | struct list_head queue[MAX_PRIO]; |
193 | }; | |
194 | ||
195 | /* | |
196 | * This is the main, per-CPU runqueue data structure. | |
197 | * | |
198 | * Locking rule: those places that want to lock multiple runqueues | |
199 | * (such as the load balancing or the thread migration code), lock | |
200 | * acquire operations must be ordered by ascending &runqueue. | |
201 | */ | |
202 | struct runqueue { | |
203 | spinlock_t lock; | |
204 | ||
205 | /* | |
206 | * nr_running and cpu_load should be in the same cacheline because | |
207 | * remote CPUs use both these fields when doing load calculation. | |
208 | */ | |
209 | unsigned long nr_running; | |
210 | #ifdef CONFIG_SMP | |
7897986b | 211 | unsigned long cpu_load[3]; |
1da177e4 LT |
212 | #endif |
213 | unsigned long long nr_switches; | |
214 | ||
215 | /* | |
216 | * This is part of a global counter where only the total sum | |
217 | * over all CPUs matters. A task can increase this counter on | |
218 | * one CPU and if it got migrated afterwards it may decrease | |
219 | * it on another CPU. Always updated under the runqueue lock: | |
220 | */ | |
221 | unsigned long nr_uninterruptible; | |
222 | ||
223 | unsigned long expired_timestamp; | |
224 | unsigned long long timestamp_last_tick; | |
225 | task_t *curr, *idle; | |
226 | struct mm_struct *prev_mm; | |
227 | prio_array_t *active, *expired, arrays[2]; | |
228 | int best_expired_prio; | |
229 | atomic_t nr_iowait; | |
230 | ||
231 | #ifdef CONFIG_SMP | |
232 | struct sched_domain *sd; | |
233 | ||
234 | /* For active balancing */ | |
235 | int active_balance; | |
236 | int push_cpu; | |
237 | ||
238 | task_t *migration_thread; | |
239 | struct list_head migration_queue; | |
240 | #endif | |
241 | ||
242 | #ifdef CONFIG_SCHEDSTATS | |
243 | /* latency stats */ | |
244 | struct sched_info rq_sched_info; | |
245 | ||
246 | /* sys_sched_yield() stats */ | |
247 | unsigned long yld_exp_empty; | |
248 | unsigned long yld_act_empty; | |
249 | unsigned long yld_both_empty; | |
250 | unsigned long yld_cnt; | |
251 | ||
252 | /* schedule() stats */ | |
253 | unsigned long sched_switch; | |
254 | unsigned long sched_cnt; | |
255 | unsigned long sched_goidle; | |
256 | ||
257 | /* try_to_wake_up() stats */ | |
258 | unsigned long ttwu_cnt; | |
259 | unsigned long ttwu_local; | |
260 | #endif | |
261 | }; | |
262 | ||
263 | static DEFINE_PER_CPU(struct runqueue, runqueues); | |
264 | ||
674311d5 NP |
265 | /* |
266 | * The domain tree (rq->sd) is protected by RCU's quiescent state transition. | |
1a20ff27 | 267 | * See detach_destroy_domains: synchronize_sched for details. |
674311d5 NP |
268 | * |
269 | * The domain tree of any CPU may only be accessed from within | |
270 | * preempt-disabled sections. | |
271 | */ | |
1da177e4 | 272 | #define for_each_domain(cpu, domain) \ |
674311d5 | 273 | for (domain = rcu_dereference(cpu_rq(cpu)->sd); domain; domain = domain->parent) |
1da177e4 LT |
274 | |
275 | #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) | |
276 | #define this_rq() (&__get_cpu_var(runqueues)) | |
277 | #define task_rq(p) cpu_rq(task_cpu(p)) | |
278 | #define cpu_curr(cpu) (cpu_rq(cpu)->curr) | |
279 | ||
1da177e4 | 280 | #ifndef prepare_arch_switch |
4866cde0 NP |
281 | # define prepare_arch_switch(next) do { } while (0) |
282 | #endif | |
283 | #ifndef finish_arch_switch | |
284 | # define finish_arch_switch(prev) do { } while (0) | |
285 | #endif | |
286 | ||
287 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
288 | static inline int task_running(runqueue_t *rq, task_t *p) | |
289 | { | |
290 | return rq->curr == p; | |
291 | } | |
292 | ||
293 | static inline void prepare_lock_switch(runqueue_t *rq, task_t *next) | |
294 | { | |
295 | } | |
296 | ||
297 | static inline void finish_lock_switch(runqueue_t *rq, task_t *prev) | |
298 | { | |
da04c035 IM |
299 | #ifdef CONFIG_DEBUG_SPINLOCK |
300 | /* this is a valid case when another task releases the spinlock */ | |
301 | rq->lock.owner = current; | |
302 | #endif | |
4866cde0 NP |
303 | spin_unlock_irq(&rq->lock); |
304 | } | |
305 | ||
306 | #else /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
307 | static inline int task_running(runqueue_t *rq, task_t *p) | |
308 | { | |
309 | #ifdef CONFIG_SMP | |
310 | return p->oncpu; | |
311 | #else | |
312 | return rq->curr == p; | |
313 | #endif | |
314 | } | |
315 | ||
316 | static inline void prepare_lock_switch(runqueue_t *rq, task_t *next) | |
317 | { | |
318 | #ifdef CONFIG_SMP | |
319 | /* | |
320 | * We can optimise this out completely for !SMP, because the | |
321 | * SMP rebalancing from interrupt is the only thing that cares | |
322 | * here. | |
323 | */ | |
324 | next->oncpu = 1; | |
325 | #endif | |
326 | #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
327 | spin_unlock_irq(&rq->lock); | |
328 | #else | |
329 | spin_unlock(&rq->lock); | |
330 | #endif | |
331 | } | |
332 | ||
333 | static inline void finish_lock_switch(runqueue_t *rq, task_t *prev) | |
334 | { | |
335 | #ifdef CONFIG_SMP | |
336 | /* | |
337 | * After ->oncpu is cleared, the task can be moved to a different CPU. | |
338 | * We must ensure this doesn't happen until the switch is completely | |
339 | * finished. | |
340 | */ | |
341 | smp_wmb(); | |
342 | prev->oncpu = 0; | |
343 | #endif | |
344 | #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW | |
345 | local_irq_enable(); | |
1da177e4 | 346 | #endif |
4866cde0 NP |
347 | } |
348 | #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ | |
1da177e4 LT |
349 | |
350 | /* | |
351 | * task_rq_lock - lock the runqueue a given task resides on and disable | |
352 | * interrupts. Note the ordering: we can safely lookup the task_rq without | |
353 | * explicitly disabling preemption. | |
354 | */ | |
355 | static inline runqueue_t *task_rq_lock(task_t *p, unsigned long *flags) | |
356 | __acquires(rq->lock) | |
357 | { | |
358 | struct runqueue *rq; | |
359 | ||
360 | repeat_lock_task: | |
361 | local_irq_save(*flags); | |
362 | rq = task_rq(p); | |
363 | spin_lock(&rq->lock); | |
364 | if (unlikely(rq != task_rq(p))) { | |
365 | spin_unlock_irqrestore(&rq->lock, *flags); | |
366 | goto repeat_lock_task; | |
367 | } | |
368 | return rq; | |
369 | } | |
370 | ||
371 | static inline void task_rq_unlock(runqueue_t *rq, unsigned long *flags) | |
372 | __releases(rq->lock) | |
373 | { | |
374 | spin_unlock_irqrestore(&rq->lock, *flags); | |
375 | } | |
376 | ||
377 | #ifdef CONFIG_SCHEDSTATS | |
378 | /* | |
379 | * bump this up when changing the output format or the meaning of an existing | |
380 | * format, so that tools can adapt (or abort) | |
381 | */ | |
68767a0a | 382 | #define SCHEDSTAT_VERSION 12 |
1da177e4 LT |
383 | |
384 | static int show_schedstat(struct seq_file *seq, void *v) | |
385 | { | |
386 | int cpu; | |
387 | ||
388 | seq_printf(seq, "version %d\n", SCHEDSTAT_VERSION); | |
389 | seq_printf(seq, "timestamp %lu\n", jiffies); | |
390 | for_each_online_cpu(cpu) { | |
391 | runqueue_t *rq = cpu_rq(cpu); | |
392 | #ifdef CONFIG_SMP | |
393 | struct sched_domain *sd; | |
394 | int dcnt = 0; | |
395 | #endif | |
396 | ||
397 | /* runqueue-specific stats */ | |
398 | seq_printf(seq, | |
399 | "cpu%d %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu", | |
400 | cpu, rq->yld_both_empty, | |
401 | rq->yld_act_empty, rq->yld_exp_empty, rq->yld_cnt, | |
402 | rq->sched_switch, rq->sched_cnt, rq->sched_goidle, | |
403 | rq->ttwu_cnt, rq->ttwu_local, | |
404 | rq->rq_sched_info.cpu_time, | |
405 | rq->rq_sched_info.run_delay, rq->rq_sched_info.pcnt); | |
406 | ||
407 | seq_printf(seq, "\n"); | |
408 | ||
409 | #ifdef CONFIG_SMP | |
410 | /* domain-specific stats */ | |
674311d5 | 411 | preempt_disable(); |
1da177e4 LT |
412 | for_each_domain(cpu, sd) { |
413 | enum idle_type itype; | |
414 | char mask_str[NR_CPUS]; | |
415 | ||
416 | cpumask_scnprintf(mask_str, NR_CPUS, sd->span); | |
417 | seq_printf(seq, "domain%d %s", dcnt++, mask_str); | |
418 | for (itype = SCHED_IDLE; itype < MAX_IDLE_TYPES; | |
419 | itype++) { | |
420 | seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu", | |
421 | sd->lb_cnt[itype], | |
422 | sd->lb_balanced[itype], | |
423 | sd->lb_failed[itype], | |
424 | sd->lb_imbalance[itype], | |
425 | sd->lb_gained[itype], | |
426 | sd->lb_hot_gained[itype], | |
427 | sd->lb_nobusyq[itype], | |
428 | sd->lb_nobusyg[itype]); | |
429 | } | |
68767a0a | 430 | seq_printf(seq, " %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu %lu\n", |
1da177e4 | 431 | sd->alb_cnt, sd->alb_failed, sd->alb_pushed, |
68767a0a NP |
432 | sd->sbe_cnt, sd->sbe_balanced, sd->sbe_pushed, |
433 | sd->sbf_cnt, sd->sbf_balanced, sd->sbf_pushed, | |
1da177e4 LT |
434 | sd->ttwu_wake_remote, sd->ttwu_move_affine, sd->ttwu_move_balance); |
435 | } | |
674311d5 | 436 | preempt_enable(); |
1da177e4 LT |
437 | #endif |
438 | } | |
439 | return 0; | |
440 | } | |
441 | ||
442 | static int schedstat_open(struct inode *inode, struct file *file) | |
443 | { | |
444 | unsigned int size = PAGE_SIZE * (1 + num_online_cpus() / 32); | |
445 | char *buf = kmalloc(size, GFP_KERNEL); | |
446 | struct seq_file *m; | |
447 | int res; | |
448 | ||
449 | if (!buf) | |
450 | return -ENOMEM; | |
451 | res = single_open(file, show_schedstat, NULL); | |
452 | if (!res) { | |
453 | m = file->private_data; | |
454 | m->buf = buf; | |
455 | m->size = size; | |
456 | } else | |
457 | kfree(buf); | |
458 | return res; | |
459 | } | |
460 | ||
461 | struct file_operations proc_schedstat_operations = { | |
462 | .open = schedstat_open, | |
463 | .read = seq_read, | |
464 | .llseek = seq_lseek, | |
465 | .release = single_release, | |
466 | }; | |
467 | ||
468 | # define schedstat_inc(rq, field) do { (rq)->field++; } while (0) | |
469 | # define schedstat_add(rq, field, amt) do { (rq)->field += (amt); } while (0) | |
470 | #else /* !CONFIG_SCHEDSTATS */ | |
471 | # define schedstat_inc(rq, field) do { } while (0) | |
472 | # define schedstat_add(rq, field, amt) do { } while (0) | |
473 | #endif | |
474 | ||
475 | /* | |
476 | * rq_lock - lock a given runqueue and disable interrupts. | |
477 | */ | |
478 | static inline runqueue_t *this_rq_lock(void) | |
479 | __acquires(rq->lock) | |
480 | { | |
481 | runqueue_t *rq; | |
482 | ||
483 | local_irq_disable(); | |
484 | rq = this_rq(); | |
485 | spin_lock(&rq->lock); | |
486 | ||
487 | return rq; | |
488 | } | |
489 | ||
1da177e4 LT |
490 | #ifdef CONFIG_SCHEDSTATS |
491 | /* | |
492 | * Called when a process is dequeued from the active array and given | |
493 | * the cpu. We should note that with the exception of interactive | |
494 | * tasks, the expired queue will become the active queue after the active | |
495 | * queue is empty, without explicitly dequeuing and requeuing tasks in the | |
496 | * expired queue. (Interactive tasks may be requeued directly to the | |
497 | * active queue, thus delaying tasks in the expired queue from running; | |
498 | * see scheduler_tick()). | |
499 | * | |
500 | * This function is only called from sched_info_arrive(), rather than | |
501 | * dequeue_task(). Even though a task may be queued and dequeued multiple | |
502 | * times as it is shuffled about, we're really interested in knowing how | |
503 | * long it was from the *first* time it was queued to the time that it | |
504 | * finally hit a cpu. | |
505 | */ | |
506 | static inline void sched_info_dequeued(task_t *t) | |
507 | { | |
508 | t->sched_info.last_queued = 0; | |
509 | } | |
510 | ||
511 | /* | |
512 | * Called when a task finally hits the cpu. We can now calculate how | |
513 | * long it was waiting to run. We also note when it began so that we | |
514 | * can keep stats on how long its timeslice is. | |
515 | */ | |
858119e1 | 516 | static void sched_info_arrive(task_t *t) |
1da177e4 LT |
517 | { |
518 | unsigned long now = jiffies, diff = 0; | |
519 | struct runqueue *rq = task_rq(t); | |
520 | ||
521 | if (t->sched_info.last_queued) | |
522 | diff = now - t->sched_info.last_queued; | |
523 | sched_info_dequeued(t); | |
524 | t->sched_info.run_delay += diff; | |
525 | t->sched_info.last_arrival = now; | |
526 | t->sched_info.pcnt++; | |
527 | ||
528 | if (!rq) | |
529 | return; | |
530 | ||
531 | rq->rq_sched_info.run_delay += diff; | |
532 | rq->rq_sched_info.pcnt++; | |
533 | } | |
534 | ||
535 | /* | |
536 | * Called when a process is queued into either the active or expired | |
537 | * array. The time is noted and later used to determine how long we | |
538 | * had to wait for us to reach the cpu. Since the expired queue will | |
539 | * become the active queue after active queue is empty, without dequeuing | |
540 | * and requeuing any tasks, we are interested in queuing to either. It | |
541 | * is unusual but not impossible for tasks to be dequeued and immediately | |
542 | * requeued in the same or another array: this can happen in sched_yield(), | |
543 | * set_user_nice(), and even load_balance() as it moves tasks from runqueue | |
544 | * to runqueue. | |
545 | * | |
546 | * This function is only called from enqueue_task(), but also only updates | |
547 | * the timestamp if it is already not set. It's assumed that | |
548 | * sched_info_dequeued() will clear that stamp when appropriate. | |
549 | */ | |
550 | static inline void sched_info_queued(task_t *t) | |
551 | { | |
552 | if (!t->sched_info.last_queued) | |
553 | t->sched_info.last_queued = jiffies; | |
554 | } | |
555 | ||
556 | /* | |
557 | * Called when a process ceases being the active-running process, either | |
558 | * voluntarily or involuntarily. Now we can calculate how long we ran. | |
559 | */ | |
560 | static inline void sched_info_depart(task_t *t) | |
561 | { | |
562 | struct runqueue *rq = task_rq(t); | |
563 | unsigned long diff = jiffies - t->sched_info.last_arrival; | |
564 | ||
565 | t->sched_info.cpu_time += diff; | |
566 | ||
567 | if (rq) | |
568 | rq->rq_sched_info.cpu_time += diff; | |
569 | } | |
570 | ||
571 | /* | |
572 | * Called when tasks are switched involuntarily due, typically, to expiring | |
573 | * their time slice. (This may also be called when switching to or from | |
574 | * the idle task.) We are only called when prev != next. | |
575 | */ | |
576 | static inline void sched_info_switch(task_t *prev, task_t *next) | |
577 | { | |
578 | struct runqueue *rq = task_rq(prev); | |
579 | ||
580 | /* | |
581 | * prev now departs the cpu. It's not interesting to record | |
582 | * stats about how efficient we were at scheduling the idle | |
583 | * process, however. | |
584 | */ | |
585 | if (prev != rq->idle) | |
586 | sched_info_depart(prev); | |
587 | ||
588 | if (next != rq->idle) | |
589 | sched_info_arrive(next); | |
590 | } | |
591 | #else | |
592 | #define sched_info_queued(t) do { } while (0) | |
593 | #define sched_info_switch(t, next) do { } while (0) | |
594 | #endif /* CONFIG_SCHEDSTATS */ | |
595 | ||
596 | /* | |
597 | * Adding/removing a task to/from a priority array: | |
598 | */ | |
599 | static void dequeue_task(struct task_struct *p, prio_array_t *array) | |
600 | { | |
601 | array->nr_active--; | |
602 | list_del(&p->run_list); | |
603 | if (list_empty(array->queue + p->prio)) | |
604 | __clear_bit(p->prio, array->bitmap); | |
605 | } | |
606 | ||
607 | static void enqueue_task(struct task_struct *p, prio_array_t *array) | |
608 | { | |
609 | sched_info_queued(p); | |
610 | list_add_tail(&p->run_list, array->queue + p->prio); | |
611 | __set_bit(p->prio, array->bitmap); | |
612 | array->nr_active++; | |
613 | p->array = array; | |
614 | } | |
615 | ||
616 | /* | |
617 | * Put task to the end of the run list without the overhead of dequeue | |
618 | * followed by enqueue. | |
619 | */ | |
620 | static void requeue_task(struct task_struct *p, prio_array_t *array) | |
621 | { | |
622 | list_move_tail(&p->run_list, array->queue + p->prio); | |
623 | } | |
624 | ||
625 | static inline void enqueue_task_head(struct task_struct *p, prio_array_t *array) | |
626 | { | |
627 | list_add(&p->run_list, array->queue + p->prio); | |
628 | __set_bit(p->prio, array->bitmap); | |
629 | array->nr_active++; | |
630 | p->array = array; | |
631 | } | |
632 | ||
633 | /* | |
634 | * effective_prio - return the priority that is based on the static | |
635 | * priority but is modified by bonuses/penalties. | |
636 | * | |
637 | * We scale the actual sleep average [0 .... MAX_SLEEP_AVG] | |
638 | * into the -5 ... 0 ... +5 bonus/penalty range. | |
639 | * | |
640 | * We use 25% of the full 0...39 priority range so that: | |
641 | * | |
642 | * 1) nice +19 interactive tasks do not preempt nice 0 CPU hogs. | |
643 | * 2) nice -20 CPU hogs do not get preempted by nice 0 tasks. | |
644 | * | |
645 | * Both properties are important to certain workloads. | |
646 | */ | |
647 | static int effective_prio(task_t *p) | |
648 | { | |
649 | int bonus, prio; | |
650 | ||
651 | if (rt_task(p)) | |
652 | return p->prio; | |
653 | ||
654 | bonus = CURRENT_BONUS(p) - MAX_BONUS / 2; | |
655 | ||
656 | prio = p->static_prio - bonus; | |
657 | if (prio < MAX_RT_PRIO) | |
658 | prio = MAX_RT_PRIO; | |
659 | if (prio > MAX_PRIO-1) | |
660 | prio = MAX_PRIO-1; | |
661 | return prio; | |
662 | } | |
663 | ||
664 | /* | |
665 | * __activate_task - move a task to the runqueue. | |
666 | */ | |
d425b274 | 667 | static void __activate_task(task_t *p, runqueue_t *rq) |
1da177e4 | 668 | { |
d425b274 CK |
669 | prio_array_t *target = rq->active; |
670 | ||
f1adad78 | 671 | if (batch_task(p)) |
d425b274 CK |
672 | target = rq->expired; |
673 | enqueue_task(p, target); | |
a2000572 | 674 | rq->nr_running++; |
1da177e4 LT |
675 | } |
676 | ||
677 | /* | |
678 | * __activate_idle_task - move idle task to the _front_ of runqueue. | |
679 | */ | |
680 | static inline void __activate_idle_task(task_t *p, runqueue_t *rq) | |
681 | { | |
682 | enqueue_task_head(p, rq->active); | |
a2000572 | 683 | rq->nr_running++; |
1da177e4 LT |
684 | } |
685 | ||
a3464a10 | 686 | static int recalc_task_prio(task_t *p, unsigned long long now) |
1da177e4 LT |
687 | { |
688 | /* Caller must always ensure 'now >= p->timestamp' */ | |
72d2854d | 689 | unsigned long sleep_time = now - p->timestamp; |
1da177e4 | 690 | |
d425b274 | 691 | if (batch_task(p)) |
b0a9499c | 692 | sleep_time = 0; |
1da177e4 LT |
693 | |
694 | if (likely(sleep_time > 0)) { | |
695 | /* | |
72d2854d CK |
696 | * This ceiling is set to the lowest priority that would allow |
697 | * a task to be reinserted into the active array on timeslice | |
698 | * completion. | |
1da177e4 | 699 | */ |
72d2854d | 700 | unsigned long ceiling = INTERACTIVE_SLEEP(p); |
e72ff0bb | 701 | |
72d2854d CK |
702 | if (p->mm && sleep_time > ceiling && p->sleep_avg < ceiling) { |
703 | /* | |
704 | * Prevents user tasks from achieving best priority | |
705 | * with one single large enough sleep. | |
706 | */ | |
707 | p->sleep_avg = ceiling; | |
708 | /* | |
709 | * Using INTERACTIVE_SLEEP() as a ceiling places a | |
710 | * nice(0) task 1ms sleep away from promotion, and | |
711 | * gives it 700ms to round-robin with no chance of | |
712 | * being demoted. This is more than generous, so | |
713 | * mark this sleep as non-interactive to prevent the | |
714 | * on-runqueue bonus logic from intervening should | |
715 | * this task not receive cpu immediately. | |
716 | */ | |
717 | p->sleep_type = SLEEP_NONINTERACTIVE; | |
1da177e4 | 718 | } else { |
1da177e4 LT |
719 | /* |
720 | * Tasks waking from uninterruptible sleep are | |
721 | * limited in their sleep_avg rise as they | |
722 | * are likely to be waiting on I/O | |
723 | */ | |
3dee386e | 724 | if (p->sleep_type == SLEEP_NONINTERACTIVE && p->mm) { |
72d2854d | 725 | if (p->sleep_avg >= ceiling) |
1da177e4 LT |
726 | sleep_time = 0; |
727 | else if (p->sleep_avg + sleep_time >= | |
72d2854d CK |
728 | ceiling) { |
729 | p->sleep_avg = ceiling; | |
730 | sleep_time = 0; | |
1da177e4 LT |
731 | } |
732 | } | |
733 | ||
734 | /* | |
735 | * This code gives a bonus to interactive tasks. | |
736 | * | |
737 | * The boost works by updating the 'average sleep time' | |
738 | * value here, based on ->timestamp. The more time a | |
739 | * task spends sleeping, the higher the average gets - | |
740 | * and the higher the priority boost gets as well. | |
741 | */ | |
742 | p->sleep_avg += sleep_time; | |
743 | ||
1da177e4 | 744 | } |
72d2854d CK |
745 | if (p->sleep_avg > NS_MAX_SLEEP_AVG) |
746 | p->sleep_avg = NS_MAX_SLEEP_AVG; | |
1da177e4 LT |
747 | } |
748 | ||
a3464a10 | 749 | return effective_prio(p); |
1da177e4 LT |
750 | } |
751 | ||
752 | /* | |
753 | * activate_task - move a task to the runqueue and do priority recalculation | |
754 | * | |
755 | * Update all the scheduling statistics stuff. (sleep average | |
756 | * calculation, priority modifiers, etc.) | |
757 | */ | |
758 | static void activate_task(task_t *p, runqueue_t *rq, int local) | |
759 | { | |
760 | unsigned long long now; | |
761 | ||
762 | now = sched_clock(); | |
763 | #ifdef CONFIG_SMP | |
764 | if (!local) { | |
765 | /* Compensate for drifting sched_clock */ | |
766 | runqueue_t *this_rq = this_rq(); | |
767 | now = (now - this_rq->timestamp_last_tick) | |
768 | + rq->timestamp_last_tick; | |
769 | } | |
770 | #endif | |
771 | ||
a47ab937 CK |
772 | if (!rt_task(p)) |
773 | p->prio = recalc_task_prio(p, now); | |
1da177e4 LT |
774 | |
775 | /* | |
776 | * This checks to make sure it's not an uninterruptible task | |
777 | * that is now waking up. | |
778 | */ | |
3dee386e | 779 | if (p->sleep_type == SLEEP_NORMAL) { |
1da177e4 LT |
780 | /* |
781 | * Tasks which were woken up by interrupts (ie. hw events) | |
782 | * are most likely of interactive nature. So we give them | |
783 | * the credit of extending their sleep time to the period | |
784 | * of time they spend on the runqueue, waiting for execution | |
785 | * on a CPU, first time around: | |
786 | */ | |
787 | if (in_interrupt()) | |
3dee386e | 788 | p->sleep_type = SLEEP_INTERRUPTED; |
1da177e4 LT |
789 | else { |
790 | /* | |
791 | * Normal first-time wakeups get a credit too for | |
792 | * on-runqueue time, but it will be weighted down: | |
793 | */ | |
3dee386e | 794 | p->sleep_type = SLEEP_INTERACTIVE; |
1da177e4 LT |
795 | } |
796 | } | |
797 | p->timestamp = now; | |
798 | ||
799 | __activate_task(p, rq); | |
800 | } | |
801 | ||
802 | /* | |
803 | * deactivate_task - remove a task from the runqueue. | |
804 | */ | |
805 | static void deactivate_task(struct task_struct *p, runqueue_t *rq) | |
806 | { | |
a2000572 | 807 | rq->nr_running--; |
1da177e4 LT |
808 | dequeue_task(p, p->array); |
809 | p->array = NULL; | |
810 | } | |
811 | ||
812 | /* | |
813 | * resched_task - mark a task 'to be rescheduled now'. | |
814 | * | |
815 | * On UP this means the setting of the need_resched flag, on SMP it | |
816 | * might also involve a cross-CPU call to trigger the scheduler on | |
817 | * the target CPU. | |
818 | */ | |
819 | #ifdef CONFIG_SMP | |
495ab9c0 AK |
820 | |
821 | #ifndef tsk_is_polling | |
822 | #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) | |
823 | #endif | |
824 | ||
1da177e4 LT |
825 | static void resched_task(task_t *p) |
826 | { | |
64c7c8f8 | 827 | int cpu; |
1da177e4 LT |
828 | |
829 | assert_spin_locked(&task_rq(p)->lock); | |
830 | ||
64c7c8f8 NP |
831 | if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED))) |
832 | return; | |
833 | ||
834 | set_tsk_thread_flag(p, TIF_NEED_RESCHED); | |
1da177e4 | 835 | |
64c7c8f8 NP |
836 | cpu = task_cpu(p); |
837 | if (cpu == smp_processor_id()) | |
838 | return; | |
839 | ||
495ab9c0 | 840 | /* NEED_RESCHED must be visible before we test polling */ |
64c7c8f8 | 841 | smp_mb(); |
495ab9c0 | 842 | if (!tsk_is_polling(p)) |
64c7c8f8 | 843 | smp_send_reschedule(cpu); |
1da177e4 LT |
844 | } |
845 | #else | |
846 | static inline void resched_task(task_t *p) | |
847 | { | |
64c7c8f8 | 848 | assert_spin_locked(&task_rq(p)->lock); |
1da177e4 LT |
849 | set_tsk_need_resched(p); |
850 | } | |
851 | #endif | |
852 | ||
853 | /** | |
854 | * task_curr - is this task currently executing on a CPU? | |
855 | * @p: the task in question. | |
856 | */ | |
857 | inline int task_curr(const task_t *p) | |
858 | { | |
859 | return cpu_curr(task_cpu(p)) == p; | |
860 | } | |
861 | ||
862 | #ifdef CONFIG_SMP | |
1da177e4 LT |
863 | typedef struct { |
864 | struct list_head list; | |
1da177e4 | 865 | |
1da177e4 LT |
866 | task_t *task; |
867 | int dest_cpu; | |
868 | ||
1da177e4 LT |
869 | struct completion done; |
870 | } migration_req_t; | |
871 | ||
872 | /* | |
873 | * The task's runqueue lock must be held. | |
874 | * Returns true if you have to wait for migration thread. | |
875 | */ | |
876 | static int migrate_task(task_t *p, int dest_cpu, migration_req_t *req) | |
877 | { | |
878 | runqueue_t *rq = task_rq(p); | |
879 | ||
880 | /* | |
881 | * If the task is not on a runqueue (and not running), then | |
882 | * it is sufficient to simply update the task's cpu field. | |
883 | */ | |
884 | if (!p->array && !task_running(rq, p)) { | |
885 | set_task_cpu(p, dest_cpu); | |
886 | return 0; | |
887 | } | |
888 | ||
889 | init_completion(&req->done); | |
1da177e4 LT |
890 | req->task = p; |
891 | req->dest_cpu = dest_cpu; | |
892 | list_add(&req->list, &rq->migration_queue); | |
893 | return 1; | |
894 | } | |
895 | ||
896 | /* | |
897 | * wait_task_inactive - wait for a thread to unschedule. | |
898 | * | |
899 | * The caller must ensure that the task *will* unschedule sometime soon, | |
900 | * else this function might spin for a *long* time. This function can't | |
901 | * be called with interrupts off, or it may introduce deadlock with | |
902 | * smp_call_function() if an IPI is sent by the same process we are | |
903 | * waiting to become inactive. | |
904 | */ | |
95cdf3b7 | 905 | void wait_task_inactive(task_t *p) |
1da177e4 LT |
906 | { |
907 | unsigned long flags; | |
908 | runqueue_t *rq; | |
909 | int preempted; | |
910 | ||
911 | repeat: | |
912 | rq = task_rq_lock(p, &flags); | |
913 | /* Must be off runqueue entirely, not preempted. */ | |
914 | if (unlikely(p->array || task_running(rq, p))) { | |
915 | /* If it's preempted, we yield. It could be a while. */ | |
916 | preempted = !task_running(rq, p); | |
917 | task_rq_unlock(rq, &flags); | |
918 | cpu_relax(); | |
919 | if (preempted) | |
920 | yield(); | |
921 | goto repeat; | |
922 | } | |
923 | task_rq_unlock(rq, &flags); | |
924 | } | |
925 | ||
926 | /*** | |
927 | * kick_process - kick a running thread to enter/exit the kernel | |
928 | * @p: the to-be-kicked thread | |
929 | * | |
930 | * Cause a process which is running on another CPU to enter | |
931 | * kernel-mode, without any delay. (to get signals handled.) | |
932 | * | |
933 | * NOTE: this function doesnt have to take the runqueue lock, | |
934 | * because all it wants to ensure is that the remote task enters | |
935 | * the kernel. If the IPI races and the task has been migrated | |
936 | * to another CPU then no harm is done and the purpose has been | |
937 | * achieved as well. | |
938 | */ | |
939 | void kick_process(task_t *p) | |
940 | { | |
941 | int cpu; | |
942 | ||
943 | preempt_disable(); | |
944 | cpu = task_cpu(p); | |
945 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
946 | smp_send_reschedule(cpu); | |
947 | preempt_enable(); | |
948 | } | |
949 | ||
950 | /* | |
951 | * Return a low guess at the load of a migration-source cpu. | |
952 | * | |
953 | * We want to under-estimate the load of migration sources, to | |
954 | * balance conservatively. | |
955 | */ | |
a2000572 | 956 | static inline unsigned long source_load(int cpu, int type) |
1da177e4 LT |
957 | { |
958 | runqueue_t *rq = cpu_rq(cpu); | |
a2000572 | 959 | unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE; |
3b0bd9bc | 960 | if (type == 0) |
a2000572 | 961 | return load_now; |
b910472d | 962 | |
a2000572 | 963 | return min(rq->cpu_load[type-1], load_now); |
1da177e4 LT |
964 | } |
965 | ||
966 | /* | |
967 | * Return a high guess at the load of a migration-target cpu | |
968 | */ | |
a2000572 | 969 | static inline unsigned long target_load(int cpu, int type) |
1da177e4 LT |
970 | { |
971 | runqueue_t *rq = cpu_rq(cpu); | |
a2000572 | 972 | unsigned long load_now = rq->nr_running * SCHED_LOAD_SCALE; |
7897986b | 973 | if (type == 0) |
a2000572 | 974 | return load_now; |
3b0bd9bc | 975 | |
a2000572 | 976 | return max(rq->cpu_load[type-1], load_now); |
1da177e4 LT |
977 | } |
978 | ||
147cbb4b NP |
979 | /* |
980 | * find_idlest_group finds and returns the least busy CPU group within the | |
981 | * domain. | |
982 | */ | |
983 | static struct sched_group * | |
984 | find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) | |
985 | { | |
986 | struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; | |
987 | unsigned long min_load = ULONG_MAX, this_load = 0; | |
988 | int load_idx = sd->forkexec_idx; | |
989 | int imbalance = 100 + (sd->imbalance_pct-100)/2; | |
990 | ||
991 | do { | |
992 | unsigned long load, avg_load; | |
993 | int local_group; | |
994 | int i; | |
995 | ||
da5a5522 BD |
996 | /* Skip over this group if it has no CPUs allowed */ |
997 | if (!cpus_intersects(group->cpumask, p->cpus_allowed)) | |
998 | goto nextgroup; | |
999 | ||
147cbb4b | 1000 | local_group = cpu_isset(this_cpu, group->cpumask); |
147cbb4b NP |
1001 | |
1002 | /* Tally up the load of all CPUs in the group */ | |
1003 | avg_load = 0; | |
1004 | ||
1005 | for_each_cpu_mask(i, group->cpumask) { | |
1006 | /* Bias balancing toward cpus of our domain */ | |
1007 | if (local_group) | |
1008 | load = source_load(i, load_idx); | |
1009 | else | |
1010 | load = target_load(i, load_idx); | |
1011 | ||
1012 | avg_load += load; | |
1013 | } | |
1014 | ||
1015 | /* Adjust by relative CPU power of the group */ | |
1016 | avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; | |
1017 | ||
1018 | if (local_group) { | |
1019 | this_load = avg_load; | |
1020 | this = group; | |
1021 | } else if (avg_load < min_load) { | |
1022 | min_load = avg_load; | |
1023 | idlest = group; | |
1024 | } | |
da5a5522 | 1025 | nextgroup: |
147cbb4b NP |
1026 | group = group->next; |
1027 | } while (group != sd->groups); | |
1028 | ||
1029 | if (!idlest || 100*this_load < imbalance*min_load) | |
1030 | return NULL; | |
1031 | return idlest; | |
1032 | } | |
1033 | ||
1034 | /* | |
1035 | * find_idlest_queue - find the idlest runqueue among the cpus in group. | |
1036 | */ | |
95cdf3b7 IM |
1037 | static int |
1038 | find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) | |
147cbb4b | 1039 | { |
da5a5522 | 1040 | cpumask_t tmp; |
147cbb4b NP |
1041 | unsigned long load, min_load = ULONG_MAX; |
1042 | int idlest = -1; | |
1043 | int i; | |
1044 | ||
da5a5522 BD |
1045 | /* Traverse only the allowed CPUs */ |
1046 | cpus_and(tmp, group->cpumask, p->cpus_allowed); | |
1047 | ||
1048 | for_each_cpu_mask(i, tmp) { | |
147cbb4b NP |
1049 | load = source_load(i, 0); |
1050 | ||
1051 | if (load < min_load || (load == min_load && i == this_cpu)) { | |
1052 | min_load = load; | |
1053 | idlest = i; | |
1054 | } | |
1055 | } | |
1056 | ||
1057 | return idlest; | |
1058 | } | |
1059 | ||
476d139c NP |
1060 | /* |
1061 | * sched_balance_self: balance the current task (running on cpu) in domains | |
1062 | * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and | |
1063 | * SD_BALANCE_EXEC. | |
1064 | * | |
1065 | * Balance, ie. select the least loaded group. | |
1066 | * | |
1067 | * Returns the target CPU number, or the same CPU if no balancing is needed. | |
1068 | * | |
1069 | * preempt must be disabled. | |
1070 | */ | |
1071 | static int sched_balance_self(int cpu, int flag) | |
1072 | { | |
1073 | struct task_struct *t = current; | |
1074 | struct sched_domain *tmp, *sd = NULL; | |
147cbb4b | 1075 | |
c96d145e | 1076 | for_each_domain(cpu, tmp) { |
476d139c NP |
1077 | if (tmp->flags & flag) |
1078 | sd = tmp; | |
c96d145e | 1079 | } |
476d139c NP |
1080 | |
1081 | while (sd) { | |
1082 | cpumask_t span; | |
1083 | struct sched_group *group; | |
1084 | int new_cpu; | |
1085 | int weight; | |
1086 | ||
1087 | span = sd->span; | |
1088 | group = find_idlest_group(sd, t, cpu); | |
1089 | if (!group) | |
1090 | goto nextlevel; | |
1091 | ||
da5a5522 | 1092 | new_cpu = find_idlest_cpu(group, t, cpu); |
476d139c NP |
1093 | if (new_cpu == -1 || new_cpu == cpu) |
1094 | goto nextlevel; | |
1095 | ||
1096 | /* Now try balancing at a lower domain level */ | |
1097 | cpu = new_cpu; | |
1098 | nextlevel: | |
1099 | sd = NULL; | |
1100 | weight = cpus_weight(span); | |
1101 | for_each_domain(cpu, tmp) { | |
1102 | if (weight <= cpus_weight(tmp->span)) | |
1103 | break; | |
1104 | if (tmp->flags & flag) | |
1105 | sd = tmp; | |
1106 | } | |
1107 | /* while loop will break here if sd == NULL */ | |
1108 | } | |
1109 | ||
1110 | return cpu; | |
1111 | } | |
1112 | ||
1113 | #endif /* CONFIG_SMP */ | |
1da177e4 LT |
1114 | |
1115 | /* | |
1116 | * wake_idle() will wake a task on an idle cpu if task->cpu is | |
1117 | * not idle and an idle cpu is available. The span of cpus to | |
1118 | * search starts with cpus closest then further out as needed, | |
1119 | * so we always favor a closer, idle cpu. | |
1120 | * | |
1121 | * Returns the CPU we should wake onto. | |
1122 | */ | |
1123 | #if defined(ARCH_HAS_SCHED_WAKE_IDLE) | |
1124 | static int wake_idle(int cpu, task_t *p) | |
1125 | { | |
1126 | cpumask_t tmp; | |
1127 | struct sched_domain *sd; | |
1128 | int i; | |
1129 | ||
1130 | if (idle_cpu(cpu)) | |
1131 | return cpu; | |
1132 | ||
1133 | for_each_domain(cpu, sd) { | |
1134 | if (sd->flags & SD_WAKE_IDLE) { | |
e0f364f4 | 1135 | cpus_and(tmp, sd->span, p->cpus_allowed); |
1da177e4 LT |
1136 | for_each_cpu_mask(i, tmp) { |
1137 | if (idle_cpu(i)) | |
1138 | return i; | |
1139 | } | |
1140 | } | |
e0f364f4 NP |
1141 | else |
1142 | break; | |
1da177e4 LT |
1143 | } |
1144 | return cpu; | |
1145 | } | |
1146 | #else | |
1147 | static inline int wake_idle(int cpu, task_t *p) | |
1148 | { | |
1149 | return cpu; | |
1150 | } | |
1151 | #endif | |
1152 | ||
1153 | /*** | |
1154 | * try_to_wake_up - wake up a thread | |
1155 | * @p: the to-be-woken-up thread | |
1156 | * @state: the mask of task states that can be woken | |
1157 | * @sync: do a synchronous wakeup? | |
1158 | * | |
1159 | * Put it on the run-queue if it's not already there. The "current" | |
1160 | * thread is always on the run-queue (except when the actual | |
1161 | * re-schedule is in progress), and as such you're allowed to do | |
1162 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1163 | * runnable without the overhead of this. | |
1164 | * | |
1165 | * returns failure only if the task is already active. | |
1166 | */ | |
95cdf3b7 | 1167 | static int try_to_wake_up(task_t *p, unsigned int state, int sync) |
1da177e4 LT |
1168 | { |
1169 | int cpu, this_cpu, success = 0; | |
1170 | unsigned long flags; | |
1171 | long old_state; | |
1172 | runqueue_t *rq; | |
1173 | #ifdef CONFIG_SMP | |
1174 | unsigned long load, this_load; | |
7897986b | 1175 | struct sched_domain *sd, *this_sd = NULL; |
1da177e4 LT |
1176 | int new_cpu; |
1177 | #endif | |
1178 | ||
1179 | rq = task_rq_lock(p, &flags); | |
1180 | old_state = p->state; | |
1181 | if (!(old_state & state)) | |
1182 | goto out; | |
1183 | ||
1184 | if (p->array) | |
1185 | goto out_running; | |
1186 | ||
1187 | cpu = task_cpu(p); | |
1188 | this_cpu = smp_processor_id(); | |
1189 | ||
1190 | #ifdef CONFIG_SMP | |
1191 | if (unlikely(task_running(rq, p))) | |
1192 | goto out_activate; | |
1193 | ||
7897986b NP |
1194 | new_cpu = cpu; |
1195 | ||
1da177e4 LT |
1196 | schedstat_inc(rq, ttwu_cnt); |
1197 | if (cpu == this_cpu) { | |
1198 | schedstat_inc(rq, ttwu_local); | |
7897986b NP |
1199 | goto out_set_cpu; |
1200 | } | |
1201 | ||
1202 | for_each_domain(this_cpu, sd) { | |
1203 | if (cpu_isset(cpu, sd->span)) { | |
1204 | schedstat_inc(sd, ttwu_wake_remote); | |
1205 | this_sd = sd; | |
1206 | break; | |
1da177e4 LT |
1207 | } |
1208 | } | |
1da177e4 | 1209 | |
7897986b | 1210 | if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed))) |
1da177e4 LT |
1211 | goto out_set_cpu; |
1212 | ||
1da177e4 | 1213 | /* |
7897986b | 1214 | * Check for affine wakeup and passive balancing possibilities. |
1da177e4 | 1215 | */ |
7897986b NP |
1216 | if (this_sd) { |
1217 | int idx = this_sd->wake_idx; | |
1218 | unsigned int imbalance; | |
1da177e4 | 1219 | |
a3f21bce NP |
1220 | imbalance = 100 + (this_sd->imbalance_pct - 100) / 2; |
1221 | ||
7897986b NP |
1222 | load = source_load(cpu, idx); |
1223 | this_load = target_load(this_cpu, idx); | |
1da177e4 | 1224 | |
7897986b NP |
1225 | new_cpu = this_cpu; /* Wake to this CPU if we can */ |
1226 | ||
a3f21bce NP |
1227 | if (this_sd->flags & SD_WAKE_AFFINE) { |
1228 | unsigned long tl = this_load; | |
1da177e4 | 1229 | /* |
a3f21bce NP |
1230 | * If sync wakeup then subtract the (maximum possible) |
1231 | * effect of the currently running task from the load | |
1232 | * of the current CPU: | |
1da177e4 | 1233 | */ |
a3f21bce NP |
1234 | if (sync) |
1235 | tl -= SCHED_LOAD_SCALE; | |
1236 | ||
1237 | if ((tl <= load && | |
1238 | tl + target_load(cpu, idx) <= SCHED_LOAD_SCALE) || | |
1239 | 100*(tl + SCHED_LOAD_SCALE) <= imbalance*load) { | |
1240 | /* | |
1241 | * This domain has SD_WAKE_AFFINE and | |
1242 | * p is cache cold in this domain, and | |
1243 | * there is no bad imbalance. | |
1244 | */ | |
1245 | schedstat_inc(this_sd, ttwu_move_affine); | |
1246 | goto out_set_cpu; | |
1247 | } | |
1248 | } | |
1249 | ||
1250 | /* | |
1251 | * Start passive balancing when half the imbalance_pct | |
1252 | * limit is reached. | |
1253 | */ | |
1254 | if (this_sd->flags & SD_WAKE_BALANCE) { | |
1255 | if (imbalance*this_load <= 100*load) { | |
1256 | schedstat_inc(this_sd, ttwu_move_balance); | |
1257 | goto out_set_cpu; | |
1258 | } | |
1da177e4 LT |
1259 | } |
1260 | } | |
1261 | ||
1262 | new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */ | |
1263 | out_set_cpu: | |
1264 | new_cpu = wake_idle(new_cpu, p); | |
1265 | if (new_cpu != cpu) { | |
1266 | set_task_cpu(p, new_cpu); | |
1267 | task_rq_unlock(rq, &flags); | |
1268 | /* might preempt at this point */ | |
1269 | rq = task_rq_lock(p, &flags); | |
1270 | old_state = p->state; | |
1271 | if (!(old_state & state)) | |
1272 | goto out; | |
1273 | if (p->array) | |
1274 | goto out_running; | |
1275 | ||
1276 | this_cpu = smp_processor_id(); | |
1277 | cpu = task_cpu(p); | |
1278 | } | |
1279 | ||
1280 | out_activate: | |
1281 | #endif /* CONFIG_SMP */ | |
1282 | if (old_state == TASK_UNINTERRUPTIBLE) { | |
1283 | rq->nr_uninterruptible--; | |
1284 | /* | |
1285 | * Tasks on involuntary sleep don't earn | |
1286 | * sleep_avg beyond just interactive state. | |
1287 | */ | |
3dee386e | 1288 | p->sleep_type = SLEEP_NONINTERACTIVE; |
e7c38cb4 | 1289 | } else |
1da177e4 | 1290 | |
d79fc0fc IM |
1291 | /* |
1292 | * Tasks that have marked their sleep as noninteractive get | |
e7c38cb4 CK |
1293 | * woken up with their sleep average not weighted in an |
1294 | * interactive way. | |
d79fc0fc | 1295 | */ |
e7c38cb4 CK |
1296 | if (old_state & TASK_NONINTERACTIVE) |
1297 | p->sleep_type = SLEEP_NONINTERACTIVE; | |
1298 | ||
1299 | ||
1300 | activate_task(p, rq, cpu == this_cpu); | |
1da177e4 LT |
1301 | /* |
1302 | * Sync wakeups (i.e. those types of wakeups where the waker | |
1303 | * has indicated that it will leave the CPU in short order) | |
1304 | * don't trigger a preemption, if the woken up task will run on | |
1305 | * this cpu. (in this case the 'I will reschedule' promise of | |
1306 | * the waker guarantees that the freshly woken up task is going | |
1307 | * to be considered on this CPU.) | |
1308 | */ | |
1da177e4 LT |
1309 | if (!sync || cpu != this_cpu) { |
1310 | if (TASK_PREEMPTS_CURR(p, rq)) | |
1311 | resched_task(rq->curr); | |
1312 | } | |
1313 | success = 1; | |
1314 | ||
1315 | out_running: | |
1316 | p->state = TASK_RUNNING; | |
1317 | out: | |
1318 | task_rq_unlock(rq, &flags); | |
1319 | ||
1320 | return success; | |
1321 | } | |
1322 | ||
95cdf3b7 | 1323 | int fastcall wake_up_process(task_t *p) |
1da177e4 LT |
1324 | { |
1325 | return try_to_wake_up(p, TASK_STOPPED | TASK_TRACED | | |
1326 | TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE, 0); | |
1327 | } | |
1328 | ||
1329 | EXPORT_SYMBOL(wake_up_process); | |
1330 | ||
1331 | int fastcall wake_up_state(task_t *p, unsigned int state) | |
1332 | { | |
1333 | return try_to_wake_up(p, state, 0); | |
1334 | } | |
1335 | ||
1da177e4 LT |
1336 | /* |
1337 | * Perform scheduler related setup for a newly forked process p. | |
1338 | * p is forked by current. | |
1339 | */ | |
476d139c | 1340 | void fastcall sched_fork(task_t *p, int clone_flags) |
1da177e4 | 1341 | { |
476d139c NP |
1342 | int cpu = get_cpu(); |
1343 | ||
1344 | #ifdef CONFIG_SMP | |
1345 | cpu = sched_balance_self(cpu, SD_BALANCE_FORK); | |
1346 | #endif | |
1347 | set_task_cpu(p, cpu); | |
1348 | ||
1da177e4 LT |
1349 | /* |
1350 | * We mark the process as running here, but have not actually | |
1351 | * inserted it onto the runqueue yet. This guarantees that | |
1352 | * nobody will actually run it, and a signal or other external | |
1353 | * event cannot wake it up and insert it on the runqueue either. | |
1354 | */ | |
1355 | p->state = TASK_RUNNING; | |
1356 | INIT_LIST_HEAD(&p->run_list); | |
1357 | p->array = NULL; | |
1da177e4 LT |
1358 | #ifdef CONFIG_SCHEDSTATS |
1359 | memset(&p->sched_info, 0, sizeof(p->sched_info)); | |
1360 | #endif | |
d6077cb8 | 1361 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4866cde0 NP |
1362 | p->oncpu = 0; |
1363 | #endif | |
1da177e4 | 1364 | #ifdef CONFIG_PREEMPT |
4866cde0 | 1365 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1366 | task_thread_info(p)->preempt_count = 1; |
1da177e4 LT |
1367 | #endif |
1368 | /* | |
1369 | * Share the timeslice between parent and child, thus the | |
1370 | * total amount of pending timeslices in the system doesn't change, | |
1371 | * resulting in more scheduling fairness. | |
1372 | */ | |
1373 | local_irq_disable(); | |
1374 | p->time_slice = (current->time_slice + 1) >> 1; | |
1375 | /* | |
1376 | * The remainder of the first timeslice might be recovered by | |
1377 | * the parent if the child exits early enough. | |
1378 | */ | |
1379 | p->first_time_slice = 1; | |
1380 | current->time_slice >>= 1; | |
1381 | p->timestamp = sched_clock(); | |
1382 | if (unlikely(!current->time_slice)) { | |
1383 | /* | |
1384 | * This case is rare, it happens when the parent has only | |
1385 | * a single jiffy left from its timeslice. Taking the | |
1386 | * runqueue lock is not a problem. | |
1387 | */ | |
1388 | current->time_slice = 1; | |
1da177e4 | 1389 | scheduler_tick(); |
476d139c NP |
1390 | } |
1391 | local_irq_enable(); | |
1392 | put_cpu(); | |
1da177e4 LT |
1393 | } |
1394 | ||
1395 | /* | |
1396 | * wake_up_new_task - wake up a newly created task for the first time. | |
1397 | * | |
1398 | * This function will do some initial scheduler statistics housekeeping | |
1399 | * that must be done for every newly created context, then puts the task | |
1400 | * on the runqueue and wakes it. | |
1401 | */ | |
95cdf3b7 | 1402 | void fastcall wake_up_new_task(task_t *p, unsigned long clone_flags) |
1da177e4 LT |
1403 | { |
1404 | unsigned long flags; | |
1405 | int this_cpu, cpu; | |
1406 | runqueue_t *rq, *this_rq; | |
1407 | ||
1408 | rq = task_rq_lock(p, &flags); | |
147cbb4b | 1409 | BUG_ON(p->state != TASK_RUNNING); |
1da177e4 | 1410 | this_cpu = smp_processor_id(); |
147cbb4b | 1411 | cpu = task_cpu(p); |
1da177e4 | 1412 | |
1da177e4 LT |
1413 | /* |
1414 | * We decrease the sleep average of forking parents | |
1415 | * and children as well, to keep max-interactive tasks | |
1416 | * from forking tasks that are max-interactive. The parent | |
1417 | * (current) is done further down, under its lock. | |
1418 | */ | |
1419 | p->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(p) * | |
1420 | CHILD_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); | |
1421 | ||
1422 | p->prio = effective_prio(p); | |
1423 | ||
1424 | if (likely(cpu == this_cpu)) { | |
1425 | if (!(clone_flags & CLONE_VM)) { | |
1426 | /* | |
1427 | * The VM isn't cloned, so we're in a good position to | |
1428 | * do child-runs-first in anticipation of an exec. This | |
1429 | * usually avoids a lot of COW overhead. | |
1430 | */ | |
1431 | if (unlikely(!current->array)) | |
1432 | __activate_task(p, rq); | |
1433 | else { | |
1434 | p->prio = current->prio; | |
1435 | list_add_tail(&p->run_list, ¤t->run_list); | |
1436 | p->array = current->array; | |
1437 | p->array->nr_active++; | |
a2000572 | 1438 | rq->nr_running++; |
1da177e4 LT |
1439 | } |
1440 | set_need_resched(); | |
1441 | } else | |
1442 | /* Run child last */ | |
1443 | __activate_task(p, rq); | |
1444 | /* | |
1445 | * We skip the following code due to cpu == this_cpu | |
1446 | * | |
1447 | * task_rq_unlock(rq, &flags); | |
1448 | * this_rq = task_rq_lock(current, &flags); | |
1449 | */ | |
1450 | this_rq = rq; | |
1451 | } else { | |
1452 | this_rq = cpu_rq(this_cpu); | |
1453 | ||
1454 | /* | |
1455 | * Not the local CPU - must adjust timestamp. This should | |
1456 | * get optimised away in the !CONFIG_SMP case. | |
1457 | */ | |
1458 | p->timestamp = (p->timestamp - this_rq->timestamp_last_tick) | |
1459 | + rq->timestamp_last_tick; | |
1460 | __activate_task(p, rq); | |
1461 | if (TASK_PREEMPTS_CURR(p, rq)) | |
1462 | resched_task(rq->curr); | |
1463 | ||
1464 | /* | |
1465 | * Parent and child are on different CPUs, now get the | |
1466 | * parent runqueue to update the parent's ->sleep_avg: | |
1467 | */ | |
1468 | task_rq_unlock(rq, &flags); | |
1469 | this_rq = task_rq_lock(current, &flags); | |
1470 | } | |
1471 | current->sleep_avg = JIFFIES_TO_NS(CURRENT_BONUS(current) * | |
1472 | PARENT_PENALTY / 100 * MAX_SLEEP_AVG / MAX_BONUS); | |
1473 | task_rq_unlock(this_rq, &flags); | |
1474 | } | |
1475 | ||
1476 | /* | |
1477 | * Potentially available exiting-child timeslices are | |
1478 | * retrieved here - this way the parent does not get | |
1479 | * penalized for creating too many threads. | |
1480 | * | |
1481 | * (this cannot be used to 'generate' timeslices | |
1482 | * artificially, because any timeslice recovered here | |
1483 | * was given away by the parent in the first place.) | |
1484 | */ | |
95cdf3b7 | 1485 | void fastcall sched_exit(task_t *p) |
1da177e4 LT |
1486 | { |
1487 | unsigned long flags; | |
1488 | runqueue_t *rq; | |
1489 | ||
1490 | /* | |
1491 | * If the child was a (relative-) CPU hog then decrease | |
1492 | * the sleep_avg of the parent as well. | |
1493 | */ | |
1494 | rq = task_rq_lock(p->parent, &flags); | |
889dfafe | 1495 | if (p->first_time_slice && task_cpu(p) == task_cpu(p->parent)) { |
1da177e4 LT |
1496 | p->parent->time_slice += p->time_slice; |
1497 | if (unlikely(p->parent->time_slice > task_timeslice(p))) | |
1498 | p->parent->time_slice = task_timeslice(p); | |
1499 | } | |
1500 | if (p->sleep_avg < p->parent->sleep_avg) | |
1501 | p->parent->sleep_avg = p->parent->sleep_avg / | |
1502 | (EXIT_WEIGHT + 1) * EXIT_WEIGHT + p->sleep_avg / | |
1503 | (EXIT_WEIGHT + 1); | |
1504 | task_rq_unlock(rq, &flags); | |
1505 | } | |
1506 | ||
4866cde0 NP |
1507 | /** |
1508 | * prepare_task_switch - prepare to switch tasks | |
1509 | * @rq: the runqueue preparing to switch | |
1510 | * @next: the task we are going to switch to. | |
1511 | * | |
1512 | * This is called with the rq lock held and interrupts off. It must | |
1513 | * be paired with a subsequent finish_task_switch after the context | |
1514 | * switch. | |
1515 | * | |
1516 | * prepare_task_switch sets up locking and calls architecture specific | |
1517 | * hooks. | |
1518 | */ | |
1519 | static inline void prepare_task_switch(runqueue_t *rq, task_t *next) | |
1520 | { | |
1521 | prepare_lock_switch(rq, next); | |
1522 | prepare_arch_switch(next); | |
1523 | } | |
1524 | ||
1da177e4 LT |
1525 | /** |
1526 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1527 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1528 | * @prev: the thread we just switched away from. |
1529 | * | |
4866cde0 NP |
1530 | * finish_task_switch must be called after the context switch, paired |
1531 | * with a prepare_task_switch call before the context switch. | |
1532 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1533 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1534 | * |
1535 | * Note that we may have delayed dropping an mm in context_switch(). If | |
1536 | * so, we finish that here outside of the runqueue lock. (Doing it | |
1537 | * with the lock held can cause deadlocks; see schedule() for | |
1538 | * details.) | |
1539 | */ | |
4866cde0 | 1540 | static inline void finish_task_switch(runqueue_t *rq, task_t *prev) |
1da177e4 LT |
1541 | __releases(rq->lock) |
1542 | { | |
1da177e4 LT |
1543 | struct mm_struct *mm = rq->prev_mm; |
1544 | unsigned long prev_task_flags; | |
1545 | ||
1546 | rq->prev_mm = NULL; | |
1547 | ||
1548 | /* | |
1549 | * A task struct has one reference for the use as "current". | |
1550 | * If a task dies, then it sets EXIT_ZOMBIE in tsk->exit_state and | |
1551 | * calls schedule one last time. The schedule call will never return, | |
1552 | * and the scheduled task must drop that reference. | |
1553 | * The test for EXIT_ZOMBIE must occur while the runqueue locks are | |
1554 | * still held, otherwise prev could be scheduled on another cpu, die | |
1555 | * there before we look at prev->state, and then the reference would | |
1556 | * be dropped twice. | |
1557 | * Manfred Spraul <manfred@colorfullife.com> | |
1558 | */ | |
1559 | prev_task_flags = prev->flags; | |
4866cde0 NP |
1560 | finish_arch_switch(prev); |
1561 | finish_lock_switch(rq, prev); | |
1da177e4 LT |
1562 | if (mm) |
1563 | mmdrop(mm); | |
c6fd91f0 | 1564 | if (unlikely(prev_task_flags & PF_DEAD)) { |
1565 | /* | |
1566 | * Remove function-return probe instances associated with this | |
1567 | * task and put them back on the free list. | |
1568 | */ | |
1569 | kprobe_flush_task(prev); | |
1da177e4 | 1570 | put_task_struct(prev); |
c6fd91f0 | 1571 | } |
1da177e4 LT |
1572 | } |
1573 | ||
1574 | /** | |
1575 | * schedule_tail - first thing a freshly forked thread must call. | |
1576 | * @prev: the thread we just switched away from. | |
1577 | */ | |
1578 | asmlinkage void schedule_tail(task_t *prev) | |
1579 | __releases(rq->lock) | |
1580 | { | |
4866cde0 NP |
1581 | runqueue_t *rq = this_rq(); |
1582 | finish_task_switch(rq, prev); | |
1583 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW | |
1584 | /* In this case, finish_task_switch does not reenable preemption */ | |
1585 | preempt_enable(); | |
1586 | #endif | |
1da177e4 LT |
1587 | if (current->set_child_tid) |
1588 | put_user(current->pid, current->set_child_tid); | |
1589 | } | |
1590 | ||
1591 | /* | |
1592 | * context_switch - switch to the new MM and the new | |
1593 | * thread's register state. | |
1594 | */ | |
1595 | static inline | |
1596 | task_t * context_switch(runqueue_t *rq, task_t *prev, task_t *next) | |
1597 | { | |
1598 | struct mm_struct *mm = next->mm; | |
1599 | struct mm_struct *oldmm = prev->active_mm; | |
1600 | ||
1601 | if (unlikely(!mm)) { | |
1602 | next->active_mm = oldmm; | |
1603 | atomic_inc(&oldmm->mm_count); | |
1604 | enter_lazy_tlb(oldmm, next); | |
1605 | } else | |
1606 | switch_mm(oldmm, mm, next); | |
1607 | ||
1608 | if (unlikely(!prev->mm)) { | |
1609 | prev->active_mm = NULL; | |
1610 | WARN_ON(rq->prev_mm); | |
1611 | rq->prev_mm = oldmm; | |
1612 | } | |
1613 | ||
1614 | /* Here we just switch the register state and the stack. */ | |
1615 | switch_to(prev, next, prev); | |
1616 | ||
1617 | return prev; | |
1618 | } | |
1619 | ||
1620 | /* | |
1621 | * nr_running, nr_uninterruptible and nr_context_switches: | |
1622 | * | |
1623 | * externally visible scheduler statistics: current number of runnable | |
1624 | * threads, current number of uninterruptible-sleeping threads, total | |
1625 | * number of context switches performed since bootup. | |
1626 | */ | |
1627 | unsigned long nr_running(void) | |
1628 | { | |
1629 | unsigned long i, sum = 0; | |
1630 | ||
1631 | for_each_online_cpu(i) | |
1632 | sum += cpu_rq(i)->nr_running; | |
1633 | ||
1634 | return sum; | |
1635 | } | |
1636 | ||
1637 | unsigned long nr_uninterruptible(void) | |
1638 | { | |
1639 | unsigned long i, sum = 0; | |
1640 | ||
0a945022 | 1641 | for_each_possible_cpu(i) |
1da177e4 LT |
1642 | sum += cpu_rq(i)->nr_uninterruptible; |
1643 | ||
1644 | /* | |
1645 | * Since we read the counters lockless, it might be slightly | |
1646 | * inaccurate. Do not allow it to go below zero though: | |
1647 | */ | |
1648 | if (unlikely((long)sum < 0)) | |
1649 | sum = 0; | |
1650 | ||
1651 | return sum; | |
1652 | } | |
1653 | ||
1654 | unsigned long long nr_context_switches(void) | |
1655 | { | |
cc94abfc SR |
1656 | int i; |
1657 | unsigned long long sum = 0; | |
1da177e4 | 1658 | |
0a945022 | 1659 | for_each_possible_cpu(i) |
1da177e4 LT |
1660 | sum += cpu_rq(i)->nr_switches; |
1661 | ||
1662 | return sum; | |
1663 | } | |
1664 | ||
1665 | unsigned long nr_iowait(void) | |
1666 | { | |
1667 | unsigned long i, sum = 0; | |
1668 | ||
0a945022 | 1669 | for_each_possible_cpu(i) |
1da177e4 LT |
1670 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
1671 | ||
1672 | return sum; | |
1673 | } | |
1674 | ||
db1b1fef JS |
1675 | unsigned long nr_active(void) |
1676 | { | |
1677 | unsigned long i, running = 0, uninterruptible = 0; | |
1678 | ||
1679 | for_each_online_cpu(i) { | |
1680 | running += cpu_rq(i)->nr_running; | |
1681 | uninterruptible += cpu_rq(i)->nr_uninterruptible; | |
1682 | } | |
1683 | ||
1684 | if (unlikely((long)uninterruptible < 0)) | |
1685 | uninterruptible = 0; | |
1686 | ||
1687 | return running + uninterruptible; | |
1688 | } | |
1689 | ||
1da177e4 LT |
1690 | #ifdef CONFIG_SMP |
1691 | ||
1692 | /* | |
1693 | * double_rq_lock - safely lock two runqueues | |
1694 | * | |
1695 | * Note this does not disable interrupts like task_rq_lock, | |
1696 | * you need to do so manually before calling. | |
1697 | */ | |
1698 | static void double_rq_lock(runqueue_t *rq1, runqueue_t *rq2) | |
1699 | __acquires(rq1->lock) | |
1700 | __acquires(rq2->lock) | |
1701 | { | |
1702 | if (rq1 == rq2) { | |
1703 | spin_lock(&rq1->lock); | |
1704 | __acquire(rq2->lock); /* Fake it out ;) */ | |
1705 | } else { | |
c96d145e | 1706 | if (rq1 < rq2) { |
1da177e4 LT |
1707 | spin_lock(&rq1->lock); |
1708 | spin_lock(&rq2->lock); | |
1709 | } else { | |
1710 | spin_lock(&rq2->lock); | |
1711 | spin_lock(&rq1->lock); | |
1712 | } | |
1713 | } | |
1714 | } | |
1715 | ||
1716 | /* | |
1717 | * double_rq_unlock - safely unlock two runqueues | |
1718 | * | |
1719 | * Note this does not restore interrupts like task_rq_unlock, | |
1720 | * you need to do so manually after calling. | |
1721 | */ | |
1722 | static void double_rq_unlock(runqueue_t *rq1, runqueue_t *rq2) | |
1723 | __releases(rq1->lock) | |
1724 | __releases(rq2->lock) | |
1725 | { | |
1726 | spin_unlock(&rq1->lock); | |
1727 | if (rq1 != rq2) | |
1728 | spin_unlock(&rq2->lock); | |
1729 | else | |
1730 | __release(rq2->lock); | |
1731 | } | |
1732 | ||
1733 | /* | |
1734 | * double_lock_balance - lock the busiest runqueue, this_rq is locked already. | |
1735 | */ | |
1736 | static void double_lock_balance(runqueue_t *this_rq, runqueue_t *busiest) | |
1737 | __releases(this_rq->lock) | |
1738 | __acquires(busiest->lock) | |
1739 | __acquires(this_rq->lock) | |
1740 | { | |
1741 | if (unlikely(!spin_trylock(&busiest->lock))) { | |
c96d145e | 1742 | if (busiest < this_rq) { |
1da177e4 LT |
1743 | spin_unlock(&this_rq->lock); |
1744 | spin_lock(&busiest->lock); | |
1745 | spin_lock(&this_rq->lock); | |
1746 | } else | |
1747 | spin_lock(&busiest->lock); | |
1748 | } | |
1749 | } | |
1750 | ||
1da177e4 LT |
1751 | /* |
1752 | * If dest_cpu is allowed for this process, migrate the task to it. | |
1753 | * This is accomplished by forcing the cpu_allowed mask to only | |
1754 | * allow dest_cpu, which will force the cpu onto dest_cpu. Then | |
1755 | * the cpu_allowed mask is restored. | |
1756 | */ | |
1757 | static void sched_migrate_task(task_t *p, int dest_cpu) | |
1758 | { | |
1759 | migration_req_t req; | |
1760 | runqueue_t *rq; | |
1761 | unsigned long flags; | |
1762 | ||
1763 | rq = task_rq_lock(p, &flags); | |
1764 | if (!cpu_isset(dest_cpu, p->cpus_allowed) | |
1765 | || unlikely(cpu_is_offline(dest_cpu))) | |
1766 | goto out; | |
1767 | ||
1768 | /* force the process onto the specified CPU */ | |
1769 | if (migrate_task(p, dest_cpu, &req)) { | |
1770 | /* Need to wait for migration thread (might exit: take ref). */ | |
1771 | struct task_struct *mt = rq->migration_thread; | |
1772 | get_task_struct(mt); | |
1773 | task_rq_unlock(rq, &flags); | |
1774 | wake_up_process(mt); | |
1775 | put_task_struct(mt); | |
1776 | wait_for_completion(&req.done); | |
1777 | return; | |
1778 | } | |
1779 | out: | |
1780 | task_rq_unlock(rq, &flags); | |
1781 | } | |
1782 | ||
1783 | /* | |
476d139c NP |
1784 | * sched_exec - execve() is a valuable balancing opportunity, because at |
1785 | * this point the task has the smallest effective memory and cache footprint. | |
1da177e4 LT |
1786 | */ |
1787 | void sched_exec(void) | |
1788 | { | |
1da177e4 | 1789 | int new_cpu, this_cpu = get_cpu(); |
476d139c | 1790 | new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
1da177e4 | 1791 | put_cpu(); |
476d139c NP |
1792 | if (new_cpu != this_cpu) |
1793 | sched_migrate_task(current, new_cpu); | |
1da177e4 LT |
1794 | } |
1795 | ||
1796 | /* | |
1797 | * pull_task - move a task from a remote runqueue to the local runqueue. | |
1798 | * Both runqueues must be locked. | |
1799 | */ | |
858119e1 | 1800 | static |
1da177e4 LT |
1801 | void pull_task(runqueue_t *src_rq, prio_array_t *src_array, task_t *p, |
1802 | runqueue_t *this_rq, prio_array_t *this_array, int this_cpu) | |
1803 | { | |
1804 | dequeue_task(p, src_array); | |
a2000572 | 1805 | src_rq->nr_running--; |
1da177e4 | 1806 | set_task_cpu(p, this_cpu); |
a2000572 | 1807 | this_rq->nr_running++; |
1da177e4 LT |
1808 | enqueue_task(p, this_array); |
1809 | p->timestamp = (p->timestamp - src_rq->timestamp_last_tick) | |
1810 | + this_rq->timestamp_last_tick; | |
1811 | /* | |
1812 | * Note that idle threads have a prio of MAX_PRIO, for this test | |
1813 | * to be always true for them. | |
1814 | */ | |
1815 | if (TASK_PREEMPTS_CURR(p, this_rq)) | |
1816 | resched_task(this_rq->curr); | |
1817 | } | |
1818 | ||
1819 | /* | |
1820 | * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? | |
1821 | */ | |
858119e1 | 1822 | static |
1da177e4 | 1823 | int can_migrate_task(task_t *p, runqueue_t *rq, int this_cpu, |
95cdf3b7 IM |
1824 | struct sched_domain *sd, enum idle_type idle, |
1825 | int *all_pinned) | |
1da177e4 LT |
1826 | { |
1827 | /* | |
1828 | * We do not migrate tasks that are: | |
1829 | * 1) running (obviously), or | |
1830 | * 2) cannot be migrated to this CPU due to cpus_allowed, or | |
1831 | * 3) are cache-hot on their current CPU. | |
1832 | */ | |
1da177e4 LT |
1833 | if (!cpu_isset(this_cpu, p->cpus_allowed)) |
1834 | return 0; | |
81026794 NP |
1835 | *all_pinned = 0; |
1836 | ||
1837 | if (task_running(rq, p)) | |
1838 | return 0; | |
1da177e4 LT |
1839 | |
1840 | /* | |
1841 | * Aggressive migration if: | |
cafb20c1 | 1842 | * 1) task is cache cold, or |
1da177e4 LT |
1843 | * 2) too many balance attempts have failed. |
1844 | */ | |
1845 | ||
cafb20c1 | 1846 | if (sd->nr_balance_failed > sd->cache_nice_tries) |
1da177e4 LT |
1847 | return 1; |
1848 | ||
1849 | if (task_hot(p, rq->timestamp_last_tick, sd)) | |
81026794 | 1850 | return 0; |
1da177e4 LT |
1851 | return 1; |
1852 | } | |
1853 | ||
1854 | /* | |
1855 | * move_tasks tries to move up to max_nr_move tasks from busiest to this_rq, | |
1856 | * as part of a balancing operation within "domain". Returns the number of | |
1857 | * tasks moved. | |
1858 | * | |
1859 | * Called with both runqueues locked. | |
1860 | */ | |
1861 | static int move_tasks(runqueue_t *this_rq, int this_cpu, runqueue_t *busiest, | |
1862 | unsigned long max_nr_move, struct sched_domain *sd, | |
81026794 | 1863 | enum idle_type idle, int *all_pinned) |
1da177e4 LT |
1864 | { |
1865 | prio_array_t *array, *dst_array; | |
1866 | struct list_head *head, *curr; | |
81026794 | 1867 | int idx, pulled = 0, pinned = 0; |
1da177e4 LT |
1868 | task_t *tmp; |
1869 | ||
81026794 | 1870 | if (max_nr_move == 0) |
1da177e4 LT |
1871 | goto out; |
1872 | ||
81026794 NP |
1873 | pinned = 1; |
1874 | ||
1da177e4 LT |
1875 | /* |
1876 | * We first consider expired tasks. Those will likely not be | |
1877 | * executed in the near future, and they are most likely to | |
1878 | * be cache-cold, thus switching CPUs has the least effect | |
1879 | * on them. | |
1880 | */ | |
1881 | if (busiest->expired->nr_active) { | |
1882 | array = busiest->expired; | |
1883 | dst_array = this_rq->expired; | |
1884 | } else { | |
1885 | array = busiest->active; | |
1886 | dst_array = this_rq->active; | |
1887 | } | |
1888 | ||
1889 | new_array: | |
1890 | /* Start searching at priority 0: */ | |
1891 | idx = 0; | |
1892 | skip_bitmap: | |
1893 | if (!idx) | |
1894 | idx = sched_find_first_bit(array->bitmap); | |
1895 | else | |
1896 | idx = find_next_bit(array->bitmap, MAX_PRIO, idx); | |
1897 | if (idx >= MAX_PRIO) { | |
1898 | if (array == busiest->expired && busiest->active->nr_active) { | |
1899 | array = busiest->active; | |
1900 | dst_array = this_rq->active; | |
1901 | goto new_array; | |
1902 | } | |
1903 | goto out; | |
1904 | } | |
1905 | ||
1906 | head = array->queue + idx; | |
1907 | curr = head->prev; | |
1908 | skip_queue: | |
1909 | tmp = list_entry(curr, task_t, run_list); | |
1910 | ||
1911 | curr = curr->prev; | |
1912 | ||
81026794 | 1913 | if (!can_migrate_task(tmp, busiest, this_cpu, sd, idle, &pinned)) { |
1da177e4 LT |
1914 | if (curr != head) |
1915 | goto skip_queue; | |
1916 | idx++; | |
1917 | goto skip_bitmap; | |
1918 | } | |
1919 | ||
1920 | #ifdef CONFIG_SCHEDSTATS | |
1921 | if (task_hot(tmp, busiest->timestamp_last_tick, sd)) | |
1922 | schedstat_inc(sd, lb_hot_gained[idle]); | |
1923 | #endif | |
1924 | ||
1925 | pull_task(busiest, array, tmp, this_rq, dst_array, this_cpu); | |
1926 | pulled++; | |
1927 | ||
1928 | /* We only want to steal up to the prescribed number of tasks. */ | |
1929 | if (pulled < max_nr_move) { | |
1930 | if (curr != head) | |
1931 | goto skip_queue; | |
1932 | idx++; | |
1933 | goto skip_bitmap; | |
1934 | } | |
1935 | out: | |
1936 | /* | |
1937 | * Right now, this is the only place pull_task() is called, | |
1938 | * so we can safely collect pull_task() stats here rather than | |
1939 | * inside pull_task(). | |
1940 | */ | |
1941 | schedstat_add(sd, lb_gained[idle], pulled); | |
81026794 NP |
1942 | |
1943 | if (all_pinned) | |
1944 | *all_pinned = pinned; | |
1da177e4 LT |
1945 | return pulled; |
1946 | } | |
1947 | ||
1948 | /* | |
1949 | * find_busiest_group finds and returns the busiest CPU group within the | |
1950 | * domain. It calculates and returns the number of tasks which should be | |
1951 | * moved to restore balance via the imbalance parameter. | |
1952 | */ | |
1953 | static struct sched_group * | |
1954 | find_busiest_group(struct sched_domain *sd, int this_cpu, | |
5969fe06 | 1955 | unsigned long *imbalance, enum idle_type idle, int *sd_idle) |
1da177e4 LT |
1956 | { |
1957 | struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; | |
1958 | unsigned long max_load, avg_load, total_load, this_load, total_pwr; | |
0c117f1b | 1959 | unsigned long max_pull; |
7897986b | 1960 | int load_idx; |
1da177e4 LT |
1961 | |
1962 | max_load = this_load = total_load = total_pwr = 0; | |
7897986b NP |
1963 | if (idle == NOT_IDLE) |
1964 | load_idx = sd->busy_idx; | |
1965 | else if (idle == NEWLY_IDLE) | |
1966 | load_idx = sd->newidle_idx; | |
1967 | else | |
1968 | load_idx = sd->idle_idx; | |
1da177e4 LT |
1969 | |
1970 | do { | |
1971 | unsigned long load; | |
1972 | int local_group; | |
1973 | int i; | |
1974 | ||
1975 | local_group = cpu_isset(this_cpu, group->cpumask); | |
1976 | ||
1977 | /* Tally up the load of all CPUs in the group */ | |
1978 | avg_load = 0; | |
1979 | ||
1980 | for_each_cpu_mask(i, group->cpumask) { | |
5969fe06 NP |
1981 | if (*sd_idle && !idle_cpu(i)) |
1982 | *sd_idle = 0; | |
1983 | ||
1da177e4 LT |
1984 | /* Bias balancing toward cpus of our domain */ |
1985 | if (local_group) | |
a2000572 | 1986 | load = target_load(i, load_idx); |
1da177e4 | 1987 | else |
a2000572 | 1988 | load = source_load(i, load_idx); |
1da177e4 LT |
1989 | |
1990 | avg_load += load; | |
1991 | } | |
1992 | ||
1993 | total_load += avg_load; | |
1994 | total_pwr += group->cpu_power; | |
1995 | ||
1996 | /* Adjust by relative CPU power of the group */ | |
1997 | avg_load = (avg_load * SCHED_LOAD_SCALE) / group->cpu_power; | |
1998 | ||
1999 | if (local_group) { | |
2000 | this_load = avg_load; | |
2001 | this = group; | |
1da177e4 LT |
2002 | } else if (avg_load > max_load) { |
2003 | max_load = avg_load; | |
2004 | busiest = group; | |
2005 | } | |
1da177e4 LT |
2006 | group = group->next; |
2007 | } while (group != sd->groups); | |
2008 | ||
0c117f1b | 2009 | if (!busiest || this_load >= max_load || max_load <= SCHED_LOAD_SCALE) |
1da177e4 LT |
2010 | goto out_balanced; |
2011 | ||
2012 | avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; | |
2013 | ||
2014 | if (this_load >= avg_load || | |
2015 | 100*max_load <= sd->imbalance_pct*this_load) | |
2016 | goto out_balanced; | |
2017 | ||
2018 | /* | |
2019 | * We're trying to get all the cpus to the average_load, so we don't | |
2020 | * want to push ourselves above the average load, nor do we wish to | |
2021 | * reduce the max loaded cpu below the average load, as either of these | |
2022 | * actions would just result in more rebalancing later, and ping-pong | |
2023 | * tasks around. Thus we look for the minimum possible imbalance. | |
2024 | * Negative imbalances (*we* are more loaded than anyone else) will | |
2025 | * be counted as no imbalance for these purposes -- we can't fix that | |
2026 | * by pulling tasks to us. Be careful of negative numbers as they'll | |
2027 | * appear as very large values with unsigned longs. | |
2028 | */ | |
0c117f1b SS |
2029 | |
2030 | /* Don't want to pull so many tasks that a group would go idle */ | |
2031 | max_pull = min(max_load - avg_load, max_load - SCHED_LOAD_SCALE); | |
2032 | ||
1da177e4 | 2033 | /* How much load to actually move to equalise the imbalance */ |
0c117f1b | 2034 | *imbalance = min(max_pull * busiest->cpu_power, |
1da177e4 LT |
2035 | (avg_load - this_load) * this->cpu_power) |
2036 | / SCHED_LOAD_SCALE; | |
2037 | ||
2038 | if (*imbalance < SCHED_LOAD_SCALE) { | |
2039 | unsigned long pwr_now = 0, pwr_move = 0; | |
2040 | unsigned long tmp; | |
2041 | ||
2042 | if (max_load - this_load >= SCHED_LOAD_SCALE*2) { | |
2043 | *imbalance = 1; | |
2044 | return busiest; | |
2045 | } | |
2046 | ||
2047 | /* | |
2048 | * OK, we don't have enough imbalance to justify moving tasks, | |
2049 | * however we may be able to increase total CPU power used by | |
2050 | * moving them. | |
2051 | */ | |
2052 | ||
2053 | pwr_now += busiest->cpu_power*min(SCHED_LOAD_SCALE, max_load); | |
2054 | pwr_now += this->cpu_power*min(SCHED_LOAD_SCALE, this_load); | |
2055 | pwr_now /= SCHED_LOAD_SCALE; | |
2056 | ||
2057 | /* Amount of load we'd subtract */ | |
2058 | tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/busiest->cpu_power; | |
2059 | if (max_load > tmp) | |
2060 | pwr_move += busiest->cpu_power*min(SCHED_LOAD_SCALE, | |
2061 | max_load - tmp); | |
2062 | ||
2063 | /* Amount of load we'd add */ | |
2064 | if (max_load*busiest->cpu_power < | |
2065 | SCHED_LOAD_SCALE*SCHED_LOAD_SCALE) | |
2066 | tmp = max_load*busiest->cpu_power/this->cpu_power; | |
2067 | else | |
2068 | tmp = SCHED_LOAD_SCALE*SCHED_LOAD_SCALE/this->cpu_power; | |
2069 | pwr_move += this->cpu_power*min(SCHED_LOAD_SCALE, this_load + tmp); | |
2070 | pwr_move /= SCHED_LOAD_SCALE; | |
2071 | ||
2072 | /* Move if we gain throughput */ | |
2073 | if (pwr_move <= pwr_now) | |
2074 | goto out_balanced; | |
2075 | ||
2076 | *imbalance = 1; | |
2077 | return busiest; | |
2078 | } | |
2079 | ||
2080 | /* Get rid of the scaling factor, rounding down as we divide */ | |
2081 | *imbalance = *imbalance / SCHED_LOAD_SCALE; | |
1da177e4 LT |
2082 | return busiest; |
2083 | ||
2084 | out_balanced: | |
1da177e4 LT |
2085 | |
2086 | *imbalance = 0; | |
2087 | return NULL; | |
2088 | } | |
2089 | ||
2090 | /* | |
2091 | * find_busiest_queue - find the busiest runqueue among the cpus in group. | |
2092 | */ | |
b910472d CK |
2093 | static runqueue_t *find_busiest_queue(struct sched_group *group, |
2094 | enum idle_type idle) | |
1da177e4 LT |
2095 | { |
2096 | unsigned long load, max_load = 0; | |
2097 | runqueue_t *busiest = NULL; | |
2098 | int i; | |
2099 | ||
2100 | for_each_cpu_mask(i, group->cpumask) { | |
a2000572 | 2101 | load = source_load(i, 0); |
1da177e4 LT |
2102 | |
2103 | if (load > max_load) { | |
2104 | max_load = load; | |
2105 | busiest = cpu_rq(i); | |
2106 | } | |
2107 | } | |
2108 | ||
2109 | return busiest; | |
2110 | } | |
2111 | ||
77391d71 NP |
2112 | /* |
2113 | * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but | |
2114 | * so long as it is large enough. | |
2115 | */ | |
2116 | #define MAX_PINNED_INTERVAL 512 | |
2117 | ||
1da177e4 LT |
2118 | /* |
2119 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2120 | * tasks if there is an imbalance. | |
2121 | * | |
2122 | * Called with this_rq unlocked. | |
2123 | */ | |
2124 | static int load_balance(int this_cpu, runqueue_t *this_rq, | |
2125 | struct sched_domain *sd, enum idle_type idle) | |
2126 | { | |
2127 | struct sched_group *group; | |
2128 | runqueue_t *busiest; | |
2129 | unsigned long imbalance; | |
77391d71 | 2130 | int nr_moved, all_pinned = 0; |
81026794 | 2131 | int active_balance = 0; |
5969fe06 NP |
2132 | int sd_idle = 0; |
2133 | ||
2134 | if (idle != NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER) | |
2135 | sd_idle = 1; | |
1da177e4 | 2136 | |
1da177e4 LT |
2137 | schedstat_inc(sd, lb_cnt[idle]); |
2138 | ||
5969fe06 | 2139 | group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle); |
1da177e4 LT |
2140 | if (!group) { |
2141 | schedstat_inc(sd, lb_nobusyg[idle]); | |
2142 | goto out_balanced; | |
2143 | } | |
2144 | ||
b910472d | 2145 | busiest = find_busiest_queue(group, idle); |
1da177e4 LT |
2146 | if (!busiest) { |
2147 | schedstat_inc(sd, lb_nobusyq[idle]); | |
2148 | goto out_balanced; | |
2149 | } | |
2150 | ||
db935dbd | 2151 | BUG_ON(busiest == this_rq); |
1da177e4 LT |
2152 | |
2153 | schedstat_add(sd, lb_imbalance[idle], imbalance); | |
2154 | ||
2155 | nr_moved = 0; | |
2156 | if (busiest->nr_running > 1) { | |
2157 | /* | |
2158 | * Attempt to move tasks. If find_busiest_group has found | |
2159 | * an imbalance but busiest->nr_running <= 1, the group is | |
2160 | * still unbalanced. nr_moved simply stays zero, so it is | |
2161 | * correctly treated as an imbalance. | |
2162 | */ | |
e17224bf | 2163 | double_rq_lock(this_rq, busiest); |
1da177e4 | 2164 | nr_moved = move_tasks(this_rq, this_cpu, busiest, |
d6d5cfaf | 2165 | imbalance, sd, idle, &all_pinned); |
e17224bf | 2166 | double_rq_unlock(this_rq, busiest); |
81026794 NP |
2167 | |
2168 | /* All tasks on this runqueue were pinned by CPU affinity */ | |
2169 | if (unlikely(all_pinned)) | |
2170 | goto out_balanced; | |
1da177e4 | 2171 | } |
81026794 | 2172 | |
1da177e4 LT |
2173 | if (!nr_moved) { |
2174 | schedstat_inc(sd, lb_failed[idle]); | |
2175 | sd->nr_balance_failed++; | |
2176 | ||
2177 | if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { | |
1da177e4 LT |
2178 | |
2179 | spin_lock(&busiest->lock); | |
fa3b6ddc SS |
2180 | |
2181 | /* don't kick the migration_thread, if the curr | |
2182 | * task on busiest cpu can't be moved to this_cpu | |
2183 | */ | |
2184 | if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { | |
2185 | spin_unlock(&busiest->lock); | |
2186 | all_pinned = 1; | |
2187 | goto out_one_pinned; | |
2188 | } | |
2189 | ||
1da177e4 LT |
2190 | if (!busiest->active_balance) { |
2191 | busiest->active_balance = 1; | |
2192 | busiest->push_cpu = this_cpu; | |
81026794 | 2193 | active_balance = 1; |
1da177e4 LT |
2194 | } |
2195 | spin_unlock(&busiest->lock); | |
81026794 | 2196 | if (active_balance) |
1da177e4 LT |
2197 | wake_up_process(busiest->migration_thread); |
2198 | ||
2199 | /* | |
2200 | * We've kicked active balancing, reset the failure | |
2201 | * counter. | |
2202 | */ | |
39507451 | 2203 | sd->nr_balance_failed = sd->cache_nice_tries+1; |
1da177e4 | 2204 | } |
81026794 | 2205 | } else |
1da177e4 LT |
2206 | sd->nr_balance_failed = 0; |
2207 | ||
81026794 | 2208 | if (likely(!active_balance)) { |
1da177e4 LT |
2209 | /* We were unbalanced, so reset the balancing interval */ |
2210 | sd->balance_interval = sd->min_interval; | |
81026794 NP |
2211 | } else { |
2212 | /* | |
2213 | * If we've begun active balancing, start to back off. This | |
2214 | * case may not be covered by the all_pinned logic if there | |
2215 | * is only 1 task on the busy runqueue (because we don't call | |
2216 | * move_tasks). | |
2217 | */ | |
2218 | if (sd->balance_interval < sd->max_interval) | |
2219 | sd->balance_interval *= 2; | |
1da177e4 LT |
2220 | } |
2221 | ||
5969fe06 NP |
2222 | if (!nr_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER) |
2223 | return -1; | |
1da177e4 LT |
2224 | return nr_moved; |
2225 | ||
2226 | out_balanced: | |
1da177e4 LT |
2227 | schedstat_inc(sd, lb_balanced[idle]); |
2228 | ||
16cfb1c0 | 2229 | sd->nr_balance_failed = 0; |
fa3b6ddc SS |
2230 | |
2231 | out_one_pinned: | |
1da177e4 | 2232 | /* tune up the balancing interval */ |
77391d71 NP |
2233 | if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
2234 | (sd->balance_interval < sd->max_interval)) | |
1da177e4 LT |
2235 | sd->balance_interval *= 2; |
2236 | ||
5969fe06 NP |
2237 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER) |
2238 | return -1; | |
1da177e4 LT |
2239 | return 0; |
2240 | } | |
2241 | ||
2242 | /* | |
2243 | * Check this_cpu to ensure it is balanced within domain. Attempt to move | |
2244 | * tasks if there is an imbalance. | |
2245 | * | |
2246 | * Called from schedule when this_rq is about to become idle (NEWLY_IDLE). | |
2247 | * this_rq is locked. | |
2248 | */ | |
2249 | static int load_balance_newidle(int this_cpu, runqueue_t *this_rq, | |
2250 | struct sched_domain *sd) | |
2251 | { | |
2252 | struct sched_group *group; | |
2253 | runqueue_t *busiest = NULL; | |
2254 | unsigned long imbalance; | |
2255 | int nr_moved = 0; | |
5969fe06 NP |
2256 | int sd_idle = 0; |
2257 | ||
2258 | if (sd->flags & SD_SHARE_CPUPOWER) | |
2259 | sd_idle = 1; | |
1da177e4 LT |
2260 | |
2261 | schedstat_inc(sd, lb_cnt[NEWLY_IDLE]); | |
5969fe06 | 2262 | group = find_busiest_group(sd, this_cpu, &imbalance, NEWLY_IDLE, &sd_idle); |
1da177e4 | 2263 | if (!group) { |
1da177e4 | 2264 | schedstat_inc(sd, lb_nobusyg[NEWLY_IDLE]); |
16cfb1c0 | 2265 | goto out_balanced; |
1da177e4 LT |
2266 | } |
2267 | ||
b910472d | 2268 | busiest = find_busiest_queue(group, NEWLY_IDLE); |
db935dbd | 2269 | if (!busiest) { |
1da177e4 | 2270 | schedstat_inc(sd, lb_nobusyq[NEWLY_IDLE]); |
16cfb1c0 | 2271 | goto out_balanced; |
1da177e4 LT |
2272 | } |
2273 | ||
db935dbd NP |
2274 | BUG_ON(busiest == this_rq); |
2275 | ||
1da177e4 | 2276 | schedstat_add(sd, lb_imbalance[NEWLY_IDLE], imbalance); |
d6d5cfaf NP |
2277 | |
2278 | nr_moved = 0; | |
2279 | if (busiest->nr_running > 1) { | |
2280 | /* Attempt to move tasks */ | |
2281 | double_lock_balance(this_rq, busiest); | |
2282 | nr_moved = move_tasks(this_rq, this_cpu, busiest, | |
81026794 | 2283 | imbalance, sd, NEWLY_IDLE, NULL); |
d6d5cfaf NP |
2284 | spin_unlock(&busiest->lock); |
2285 | } | |
2286 | ||
5969fe06 | 2287 | if (!nr_moved) { |
1da177e4 | 2288 | schedstat_inc(sd, lb_failed[NEWLY_IDLE]); |
5969fe06 NP |
2289 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER) |
2290 | return -1; | |
2291 | } else | |
16cfb1c0 | 2292 | sd->nr_balance_failed = 0; |
1da177e4 | 2293 | |
1da177e4 | 2294 | return nr_moved; |
16cfb1c0 NP |
2295 | |
2296 | out_balanced: | |
2297 | schedstat_inc(sd, lb_balanced[NEWLY_IDLE]); | |
5969fe06 NP |
2298 | if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER) |
2299 | return -1; | |
16cfb1c0 NP |
2300 | sd->nr_balance_failed = 0; |
2301 | return 0; | |
1da177e4 LT |
2302 | } |
2303 | ||
2304 | /* | |
2305 | * idle_balance is called by schedule() if this_cpu is about to become | |
2306 | * idle. Attempts to pull tasks from other CPUs. | |
2307 | */ | |
858119e1 | 2308 | static void idle_balance(int this_cpu, runqueue_t *this_rq) |
1da177e4 LT |
2309 | { |
2310 | struct sched_domain *sd; | |
2311 | ||
2312 | for_each_domain(this_cpu, sd) { | |
2313 | if (sd->flags & SD_BALANCE_NEWIDLE) { | |
2314 | if (load_balance_newidle(this_cpu, this_rq, sd)) { | |
2315 | /* We've pulled tasks over so stop searching */ | |
2316 | break; | |
2317 | } | |
2318 | } | |
2319 | } | |
2320 | } | |
2321 | ||
2322 | /* | |
2323 | * active_load_balance is run by migration threads. It pushes running tasks | |
2324 | * off the busiest CPU onto idle CPUs. It requires at least 1 task to be | |
2325 | * running on each physical CPU where possible, and avoids physical / | |
2326 | * logical imbalances. | |
2327 | * | |
2328 | * Called with busiest_rq locked. | |
2329 | */ | |
2330 | static void active_load_balance(runqueue_t *busiest_rq, int busiest_cpu) | |
2331 | { | |
2332 | struct sched_domain *sd; | |
1da177e4 | 2333 | runqueue_t *target_rq; |
39507451 NP |
2334 | int target_cpu = busiest_rq->push_cpu; |
2335 | ||
2336 | if (busiest_rq->nr_running <= 1) | |
2337 | /* no task to move */ | |
2338 | return; | |
2339 | ||
2340 | target_rq = cpu_rq(target_cpu); | |
1da177e4 LT |
2341 | |
2342 | /* | |
39507451 NP |
2343 | * This condition is "impossible", if it occurs |
2344 | * we need to fix it. Originally reported by | |
2345 | * Bjorn Helgaas on a 128-cpu setup. | |
1da177e4 | 2346 | */ |
39507451 | 2347 | BUG_ON(busiest_rq == target_rq); |
1da177e4 | 2348 | |
39507451 NP |
2349 | /* move a task from busiest_rq to target_rq */ |
2350 | double_lock_balance(busiest_rq, target_rq); | |
2351 | ||
2352 | /* Search for an sd spanning us and the target CPU. */ | |
c96d145e | 2353 | for_each_domain(target_cpu, sd) { |
39507451 NP |
2354 | if ((sd->flags & SD_LOAD_BALANCE) && |
2355 | cpu_isset(busiest_cpu, sd->span)) | |
2356 | break; | |
c96d145e | 2357 | } |
39507451 NP |
2358 | |
2359 | if (unlikely(sd == NULL)) | |
2360 | goto out; | |
2361 | ||
2362 | schedstat_inc(sd, alb_cnt); | |
2363 | ||
2364 | if (move_tasks(target_rq, target_cpu, busiest_rq, 1, sd, SCHED_IDLE, NULL)) | |
2365 | schedstat_inc(sd, alb_pushed); | |
2366 | else | |
2367 | schedstat_inc(sd, alb_failed); | |
2368 | out: | |
2369 | spin_unlock(&target_rq->lock); | |
1da177e4 LT |
2370 | } |
2371 | ||
2372 | /* | |
2373 | * rebalance_tick will get called every timer tick, on every CPU. | |
2374 | * | |
2375 | * It checks each scheduling domain to see if it is due to be balanced, | |
2376 | * and initiates a balancing operation if so. | |
2377 | * | |
2378 | * Balancing parameters are set up in arch_init_sched_domains. | |
2379 | */ | |
2380 | ||
2381 | /* Don't have all balancing operations going off at once */ | |
2382 | #define CPU_OFFSET(cpu) (HZ * cpu / NR_CPUS) | |
2383 | ||
2384 | static void rebalance_tick(int this_cpu, runqueue_t *this_rq, | |
2385 | enum idle_type idle) | |
2386 | { | |
2387 | unsigned long old_load, this_load; | |
2388 | unsigned long j = jiffies + CPU_OFFSET(this_cpu); | |
2389 | struct sched_domain *sd; | |
7897986b | 2390 | int i; |
1da177e4 | 2391 | |
1da177e4 | 2392 | this_load = this_rq->nr_running * SCHED_LOAD_SCALE; |
7897986b NP |
2393 | /* Update our load */ |
2394 | for (i = 0; i < 3; i++) { | |
2395 | unsigned long new_load = this_load; | |
2396 | int scale = 1 << i; | |
2397 | old_load = this_rq->cpu_load[i]; | |
2398 | /* | |
2399 | * Round up the averaging division if load is increasing. This | |
2400 | * prevents us from getting stuck on 9 if the load is 10, for | |
2401 | * example. | |
2402 | */ | |
2403 | if (new_load > old_load) | |
2404 | new_load += scale-1; | |
2405 | this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) / scale; | |
2406 | } | |
1da177e4 LT |
2407 | |
2408 | for_each_domain(this_cpu, sd) { | |
2409 | unsigned long interval; | |
2410 | ||
2411 | if (!(sd->flags & SD_LOAD_BALANCE)) | |
2412 | continue; | |
2413 | ||
2414 | interval = sd->balance_interval; | |
2415 | if (idle != SCHED_IDLE) | |
2416 | interval *= sd->busy_factor; | |
2417 | ||
2418 | /* scale ms to jiffies */ | |
2419 | interval = msecs_to_jiffies(interval); | |
2420 | if (unlikely(!interval)) | |
2421 | interval = 1; | |
2422 | ||
2423 | if (j - sd->last_balance >= interval) { | |
2424 | if (load_balance(this_cpu, this_rq, sd, idle)) { | |
fa3b6ddc SS |
2425 | /* |
2426 | * We've pulled tasks over so either we're no | |
5969fe06 NP |
2427 | * longer idle, or one of our SMT siblings is |
2428 | * not idle. | |
2429 | */ | |
1da177e4 LT |
2430 | idle = NOT_IDLE; |
2431 | } | |
2432 | sd->last_balance += interval; | |
2433 | } | |
2434 | } | |
2435 | } | |
2436 | #else | |
2437 | /* | |
2438 | * on UP we do not need to balance between CPUs: | |
2439 | */ | |
2440 | static inline void rebalance_tick(int cpu, runqueue_t *rq, enum idle_type idle) | |
2441 | { | |
2442 | } | |
2443 | static inline void idle_balance(int cpu, runqueue_t *rq) | |
2444 | { | |
2445 | } | |
2446 | #endif | |
2447 | ||
2448 | static inline int wake_priority_sleeper(runqueue_t *rq) | |
2449 | { | |
2450 | int ret = 0; | |
2451 | #ifdef CONFIG_SCHED_SMT | |
2452 | spin_lock(&rq->lock); | |
2453 | /* | |
2454 | * If an SMT sibling task has been put to sleep for priority | |
2455 | * reasons reschedule the idle task to see if it can now run. | |
2456 | */ | |
2457 | if (rq->nr_running) { | |
2458 | resched_task(rq->idle); | |
2459 | ret = 1; | |
2460 | } | |
2461 | spin_unlock(&rq->lock); | |
2462 | #endif | |
2463 | return ret; | |
2464 | } | |
2465 | ||
2466 | DEFINE_PER_CPU(struct kernel_stat, kstat); | |
2467 | ||
2468 | EXPORT_PER_CPU_SYMBOL(kstat); | |
2469 | ||
2470 | /* | |
2471 | * This is called on clock ticks and on context switches. | |
2472 | * Bank in p->sched_time the ns elapsed since the last tick or switch. | |
2473 | */ | |
2474 | static inline void update_cpu_clock(task_t *p, runqueue_t *rq, | |
2475 | unsigned long long now) | |
2476 | { | |
2477 | unsigned long long last = max(p->timestamp, rq->timestamp_last_tick); | |
2478 | p->sched_time += now - last; | |
2479 | } | |
2480 | ||
2481 | /* | |
2482 | * Return current->sched_time plus any more ns on the sched_clock | |
2483 | * that have not yet been banked. | |
2484 | */ | |
2485 | unsigned long long current_sched_time(const task_t *tsk) | |
2486 | { | |
2487 | unsigned long long ns; | |
2488 | unsigned long flags; | |
2489 | local_irq_save(flags); | |
2490 | ns = max(tsk->timestamp, task_rq(tsk)->timestamp_last_tick); | |
2491 | ns = tsk->sched_time + (sched_clock() - ns); | |
2492 | local_irq_restore(flags); | |
2493 | return ns; | |
2494 | } | |
2495 | ||
f1adad78 LT |
2496 | /* |
2497 | * We place interactive tasks back into the active array, if possible. | |
2498 | * | |
2499 | * To guarantee that this does not starve expired tasks we ignore the | |
2500 | * interactivity of a task if the first expired task had to wait more | |
2501 | * than a 'reasonable' amount of time. This deadline timeout is | |
2502 | * load-dependent, as the frequency of array switched decreases with | |
2503 | * increasing number of running tasks. We also ignore the interactivity | |
2504 | * if a better static_prio task has expired: | |
2505 | */ | |
2506 | #define EXPIRED_STARVING(rq) \ | |
2507 | ((STARVATION_LIMIT && ((rq)->expired_timestamp && \ | |
2508 | (jiffies - (rq)->expired_timestamp >= \ | |
2509 | STARVATION_LIMIT * ((rq)->nr_running) + 1))) || \ | |
2510 | ((rq)->curr->static_prio > (rq)->best_expired_prio)) | |
2511 | ||
1da177e4 LT |
2512 | /* |
2513 | * Account user cpu time to a process. | |
2514 | * @p: the process that the cpu time gets accounted to | |
2515 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
2516 | * @cputime: the cpu time spent in user space since the last update | |
2517 | */ | |
2518 | void account_user_time(struct task_struct *p, cputime_t cputime) | |
2519 | { | |
2520 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
2521 | cputime64_t tmp; | |
2522 | ||
2523 | p->utime = cputime_add(p->utime, cputime); | |
2524 | ||
2525 | /* Add user time to cpustat. */ | |
2526 | tmp = cputime_to_cputime64(cputime); | |
2527 | if (TASK_NICE(p) > 0) | |
2528 | cpustat->nice = cputime64_add(cpustat->nice, tmp); | |
2529 | else | |
2530 | cpustat->user = cputime64_add(cpustat->user, tmp); | |
2531 | } | |
2532 | ||
2533 | /* | |
2534 | * Account system cpu time to a process. | |
2535 | * @p: the process that the cpu time gets accounted to | |
2536 | * @hardirq_offset: the offset to subtract from hardirq_count() | |
2537 | * @cputime: the cpu time spent in kernel space since the last update | |
2538 | */ | |
2539 | void account_system_time(struct task_struct *p, int hardirq_offset, | |
2540 | cputime_t cputime) | |
2541 | { | |
2542 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
2543 | runqueue_t *rq = this_rq(); | |
2544 | cputime64_t tmp; | |
2545 | ||
2546 | p->stime = cputime_add(p->stime, cputime); | |
2547 | ||
2548 | /* Add system time to cpustat. */ | |
2549 | tmp = cputime_to_cputime64(cputime); | |
2550 | if (hardirq_count() - hardirq_offset) | |
2551 | cpustat->irq = cputime64_add(cpustat->irq, tmp); | |
2552 | else if (softirq_count()) | |
2553 | cpustat->softirq = cputime64_add(cpustat->softirq, tmp); | |
2554 | else if (p != rq->idle) | |
2555 | cpustat->system = cputime64_add(cpustat->system, tmp); | |
2556 | else if (atomic_read(&rq->nr_iowait) > 0) | |
2557 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
2558 | else | |
2559 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
2560 | /* Account for system time used */ | |
2561 | acct_update_integrals(p); | |
1da177e4 LT |
2562 | } |
2563 | ||
2564 | /* | |
2565 | * Account for involuntary wait time. | |
2566 | * @p: the process from which the cpu time has been stolen | |
2567 | * @steal: the cpu time spent in involuntary wait | |
2568 | */ | |
2569 | void account_steal_time(struct task_struct *p, cputime_t steal) | |
2570 | { | |
2571 | struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; | |
2572 | cputime64_t tmp = cputime_to_cputime64(steal); | |
2573 | runqueue_t *rq = this_rq(); | |
2574 | ||
2575 | if (p == rq->idle) { | |
2576 | p->stime = cputime_add(p->stime, steal); | |
2577 | if (atomic_read(&rq->nr_iowait) > 0) | |
2578 | cpustat->iowait = cputime64_add(cpustat->iowait, tmp); | |
2579 | else | |
2580 | cpustat->idle = cputime64_add(cpustat->idle, tmp); | |
2581 | } else | |
2582 | cpustat->steal = cputime64_add(cpustat->steal, tmp); | |
2583 | } | |
2584 | ||
2585 | /* | |
2586 | * This function gets called by the timer code, with HZ frequency. | |
2587 | * We call it with interrupts disabled. | |
2588 | * | |
2589 | * It also gets called by the fork code, when changing the parent's | |
2590 | * timeslices. | |
2591 | */ | |
2592 | void scheduler_tick(void) | |
2593 | { | |
2594 | int cpu = smp_processor_id(); | |
2595 | runqueue_t *rq = this_rq(); | |
2596 | task_t *p = current; | |
2597 | unsigned long long now = sched_clock(); | |
2598 | ||
2599 | update_cpu_clock(p, rq, now); | |
2600 | ||
2601 | rq->timestamp_last_tick = now; | |
2602 | ||
2603 | if (p == rq->idle) { | |
2604 | if (wake_priority_sleeper(rq)) | |
2605 | goto out; | |
2606 | rebalance_tick(cpu, rq, SCHED_IDLE); | |
2607 | return; | |
2608 | } | |
2609 | ||
2610 | /* Task might have expired already, but not scheduled off yet */ | |
2611 | if (p->array != rq->active) { | |
2612 | set_tsk_need_resched(p); | |
2613 | goto out; | |
2614 | } | |
2615 | spin_lock(&rq->lock); | |
2616 | /* | |
2617 | * The task was running during this tick - update the | |
2618 | * time slice counter. Note: we do not update a thread's | |
2619 | * priority until it either goes to sleep or uses up its | |
2620 | * timeslice. This makes it possible for interactive tasks | |
2621 | * to use up their timeslices at their highest priority levels. | |
2622 | */ | |
2623 | if (rt_task(p)) { | |
2624 | /* | |
2625 | * RR tasks need a special form of timeslice management. | |
2626 | * FIFO tasks have no timeslices. | |
2627 | */ | |
2628 | if ((p->policy == SCHED_RR) && !--p->time_slice) { | |
2629 | p->time_slice = task_timeslice(p); | |
2630 | p->first_time_slice = 0; | |
2631 | set_tsk_need_resched(p); | |
2632 | ||
2633 | /* put it at the end of the queue: */ | |
2634 | requeue_task(p, rq->active); | |
2635 | } | |
2636 | goto out_unlock; | |
2637 | } | |
2638 | if (!--p->time_slice) { | |
2639 | dequeue_task(p, rq->active); | |
2640 | set_tsk_need_resched(p); | |
2641 | p->prio = effective_prio(p); | |
2642 | p->time_slice = task_timeslice(p); | |
2643 | p->first_time_slice = 0; | |
2644 | ||
2645 | if (!rq->expired_timestamp) | |
2646 | rq->expired_timestamp = jiffies; | |
f1adad78 | 2647 | if (!TASK_INTERACTIVE(p) || EXPIRED_STARVING(rq)) { |
1da177e4 LT |
2648 | enqueue_task(p, rq->expired); |
2649 | if (p->static_prio < rq->best_expired_prio) | |
2650 | rq->best_expired_prio = p->static_prio; | |
2651 | } else | |
2652 | enqueue_task(p, rq->active); | |
2653 | } else { | |
2654 | /* | |
2655 | * Prevent a too long timeslice allowing a task to monopolize | |
2656 | * the CPU. We do this by splitting up the timeslice into | |
2657 | * smaller pieces. | |
2658 | * | |
2659 | * Note: this does not mean the task's timeslices expire or | |
2660 | * get lost in any way, they just might be preempted by | |
2661 | * another task of equal priority. (one with higher | |
2662 | * priority would have preempted this task already.) We | |
2663 | * requeue this task to the end of the list on this priority | |
2664 | * level, which is in essence a round-robin of tasks with | |
2665 | * equal priority. | |
2666 | * | |
2667 | * This only applies to tasks in the interactive | |
2668 | * delta range with at least TIMESLICE_GRANULARITY to requeue. | |
2669 | */ | |
2670 | if (TASK_INTERACTIVE(p) && !((task_timeslice(p) - | |
2671 | p->time_slice) % TIMESLICE_GRANULARITY(p)) && | |
2672 | (p->time_slice >= TIMESLICE_GRANULARITY(p)) && | |
2673 | (p->array == rq->active)) { | |
2674 | ||
2675 | requeue_task(p, rq->active); | |
2676 | set_tsk_need_resched(p); | |
2677 | } | |
2678 | } | |
2679 | out_unlock: | |
2680 | spin_unlock(&rq->lock); | |
2681 | out: | |
2682 | rebalance_tick(cpu, rq, NOT_IDLE); | |
2683 | } | |
2684 | ||
2685 | #ifdef CONFIG_SCHED_SMT | |
fc38ed75 CK |
2686 | static inline void wakeup_busy_runqueue(runqueue_t *rq) |
2687 | { | |
2688 | /* If an SMT runqueue is sleeping due to priority reasons wake it up */ | |
2689 | if (rq->curr == rq->idle && rq->nr_running) | |
2690 | resched_task(rq->idle); | |
2691 | } | |
2692 | ||
c96d145e CK |
2693 | /* |
2694 | * Called with interrupt disabled and this_rq's runqueue locked. | |
2695 | */ | |
2696 | static void wake_sleeping_dependent(int this_cpu) | |
1da177e4 | 2697 | { |
41c7ce9a | 2698 | struct sched_domain *tmp, *sd = NULL; |
1da177e4 LT |
2699 | int i; |
2700 | ||
c96d145e CK |
2701 | for_each_domain(this_cpu, tmp) { |
2702 | if (tmp->flags & SD_SHARE_CPUPOWER) { | |
41c7ce9a | 2703 | sd = tmp; |
c96d145e CK |
2704 | break; |
2705 | } | |
2706 | } | |
41c7ce9a NP |
2707 | |
2708 | if (!sd) | |
1da177e4 LT |
2709 | return; |
2710 | ||
c96d145e | 2711 | for_each_cpu_mask(i, sd->span) { |
1da177e4 LT |
2712 | runqueue_t *smt_rq = cpu_rq(i); |
2713 | ||
c96d145e CK |
2714 | if (i == this_cpu) |
2715 | continue; | |
2716 | if (unlikely(!spin_trylock(&smt_rq->lock))) | |
2717 | continue; | |
2718 | ||
fc38ed75 | 2719 | wakeup_busy_runqueue(smt_rq); |
c96d145e | 2720 | spin_unlock(&smt_rq->lock); |
1da177e4 | 2721 | } |
1da177e4 LT |
2722 | } |
2723 | ||
67f9a619 IM |
2724 | /* |
2725 | * number of 'lost' timeslices this task wont be able to fully | |
2726 | * utilize, if another task runs on a sibling. This models the | |
2727 | * slowdown effect of other tasks running on siblings: | |
2728 | */ | |
2729 | static inline unsigned long smt_slice(task_t *p, struct sched_domain *sd) | |
2730 | { | |
2731 | return p->time_slice * (100 - sd->per_cpu_gain) / 100; | |
2732 | } | |
2733 | ||
c96d145e CK |
2734 | /* |
2735 | * To minimise lock contention and not have to drop this_rq's runlock we only | |
2736 | * trylock the sibling runqueues and bypass those runqueues if we fail to | |
2737 | * acquire their lock. As we only trylock the normal locking order does not | |
2738 | * need to be obeyed. | |
2739 | */ | |
2740 | static int dependent_sleeper(int this_cpu, runqueue_t *this_rq, task_t *p) | |
1da177e4 | 2741 | { |
41c7ce9a | 2742 | struct sched_domain *tmp, *sd = NULL; |
1da177e4 | 2743 | int ret = 0, i; |
1da177e4 | 2744 | |
c96d145e CK |
2745 | /* kernel/rt threads do not participate in dependent sleeping */ |
2746 | if (!p->mm || rt_task(p)) | |
2747 | return 0; | |
2748 | ||
2749 | for_each_domain(this_cpu, tmp) { | |
2750 | if (tmp->flags & SD_SHARE_CPUPOWER) { | |
41c7ce9a | 2751 | sd = tmp; |
c96d145e CK |
2752 | break; |
2753 | } | |
2754 | } | |
41c7ce9a NP |
2755 | |
2756 | if (!sd) | |
1da177e4 LT |
2757 | return 0; |
2758 | ||
c96d145e CK |
2759 | for_each_cpu_mask(i, sd->span) { |
2760 | runqueue_t *smt_rq; | |
2761 | task_t *smt_curr; | |
1da177e4 | 2762 | |
c96d145e CK |
2763 | if (i == this_cpu) |
2764 | continue; | |
1da177e4 | 2765 | |
c96d145e CK |
2766 | smt_rq = cpu_rq(i); |
2767 | if (unlikely(!spin_trylock(&smt_rq->lock))) | |
2768 | continue; | |
1da177e4 | 2769 | |
c96d145e | 2770 | smt_curr = smt_rq->curr; |
1da177e4 | 2771 | |
c96d145e CK |
2772 | if (!smt_curr->mm) |
2773 | goto unlock; | |
fc38ed75 | 2774 | |
1da177e4 LT |
2775 | /* |
2776 | * If a user task with lower static priority than the | |
2777 | * running task on the SMT sibling is trying to schedule, | |
2778 | * delay it till there is proportionately less timeslice | |
2779 | * left of the sibling task to prevent a lower priority | |
2780 | * task from using an unfair proportion of the | |
2781 | * physical cpu's resources. -ck | |
2782 | */ | |
fc38ed75 CK |
2783 | if (rt_task(smt_curr)) { |
2784 | /* | |
2785 | * With real time tasks we run non-rt tasks only | |
2786 | * per_cpu_gain% of the time. | |
2787 | */ | |
2788 | if ((jiffies % DEF_TIMESLICE) > | |
2789 | (sd->per_cpu_gain * DEF_TIMESLICE / 100)) | |
2790 | ret = 1; | |
c96d145e | 2791 | } else { |
67f9a619 IM |
2792 | if (smt_curr->static_prio < p->static_prio && |
2793 | !TASK_PREEMPTS_CURR(p, smt_rq) && | |
2794 | smt_slice(smt_curr, sd) > task_timeslice(p)) | |
fc38ed75 | 2795 | ret = 1; |
fc38ed75 | 2796 | } |
c96d145e CK |
2797 | unlock: |
2798 | spin_unlock(&smt_rq->lock); | |
1da177e4 | 2799 | } |
1da177e4 LT |
2800 | return ret; |
2801 | } | |
2802 | #else | |
c96d145e | 2803 | static inline void wake_sleeping_dependent(int this_cpu) |
1da177e4 LT |
2804 | { |
2805 | } | |
2806 | ||
c96d145e CK |
2807 | static inline int dependent_sleeper(int this_cpu, runqueue_t *this_rq, |
2808 | task_t *p) | |
1da177e4 LT |
2809 | { |
2810 | return 0; | |
2811 | } | |
2812 | #endif | |
2813 | ||
2814 | #if defined(CONFIG_PREEMPT) && defined(CONFIG_DEBUG_PREEMPT) | |
2815 | ||
2816 | void fastcall add_preempt_count(int val) | |
2817 | { | |
2818 | /* | |
2819 | * Underflow? | |
2820 | */ | |
be5b4fbd | 2821 | BUG_ON((preempt_count() < 0)); |
1da177e4 LT |
2822 | preempt_count() += val; |
2823 | /* | |
2824 | * Spinlock count overflowing soon? | |
2825 | */ | |
2826 | BUG_ON((preempt_count() & PREEMPT_MASK) >= PREEMPT_MASK-10); | |
2827 | } | |
2828 | EXPORT_SYMBOL(add_preempt_count); | |
2829 | ||
2830 | void fastcall sub_preempt_count(int val) | |
2831 | { | |
2832 | /* | |
2833 | * Underflow? | |
2834 | */ | |
2835 | BUG_ON(val > preempt_count()); | |
2836 | /* | |
2837 | * Is the spinlock portion underflowing? | |
2838 | */ | |
2839 | BUG_ON((val < PREEMPT_MASK) && !(preempt_count() & PREEMPT_MASK)); | |
2840 | preempt_count() -= val; | |
2841 | } | |
2842 | EXPORT_SYMBOL(sub_preempt_count); | |
2843 | ||
2844 | #endif | |
2845 | ||
3dee386e CK |
2846 | static inline int interactive_sleep(enum sleep_type sleep_type) |
2847 | { | |
2848 | return (sleep_type == SLEEP_INTERACTIVE || | |
2849 | sleep_type == SLEEP_INTERRUPTED); | |
2850 | } | |
2851 | ||
1da177e4 LT |
2852 | /* |
2853 | * schedule() is the main scheduler function. | |
2854 | */ | |
2855 | asmlinkage void __sched schedule(void) | |
2856 | { | |
2857 | long *switch_count; | |
2858 | task_t *prev, *next; | |
2859 | runqueue_t *rq; | |
2860 | prio_array_t *array; | |
2861 | struct list_head *queue; | |
2862 | unsigned long long now; | |
2863 | unsigned long run_time; | |
a3464a10 | 2864 | int cpu, idx, new_prio; |
1da177e4 LT |
2865 | |
2866 | /* | |
2867 | * Test if we are atomic. Since do_exit() needs to call into | |
2868 | * schedule() atomically, we ignore that path for now. | |
2869 | * Otherwise, whine if we are scheduling when we should not be. | |
2870 | */ | |
77e4bfbc AM |
2871 | if (unlikely(in_atomic() && !current->exit_state)) { |
2872 | printk(KERN_ERR "BUG: scheduling while atomic: " | |
2873 | "%s/0x%08x/%d\n", | |
2874 | current->comm, preempt_count(), current->pid); | |
2875 | dump_stack(); | |
1da177e4 LT |
2876 | } |
2877 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); | |
2878 | ||
2879 | need_resched: | |
2880 | preempt_disable(); | |
2881 | prev = current; | |
2882 | release_kernel_lock(prev); | |
2883 | need_resched_nonpreemptible: | |
2884 | rq = this_rq(); | |
2885 | ||
2886 | /* | |
2887 | * The idle thread is not allowed to schedule! | |
2888 | * Remove this check after it has been exercised a bit. | |
2889 | */ | |
2890 | if (unlikely(prev == rq->idle) && prev->state != TASK_RUNNING) { | |
2891 | printk(KERN_ERR "bad: scheduling from the idle thread!\n"); | |
2892 | dump_stack(); | |
2893 | } | |
2894 | ||
2895 | schedstat_inc(rq, sched_cnt); | |
2896 | now = sched_clock(); | |
238628ed | 2897 | if (likely((long long)(now - prev->timestamp) < NS_MAX_SLEEP_AVG)) { |
1da177e4 | 2898 | run_time = now - prev->timestamp; |
238628ed | 2899 | if (unlikely((long long)(now - prev->timestamp) < 0)) |
1da177e4 LT |
2900 | run_time = 0; |
2901 | } else | |
2902 | run_time = NS_MAX_SLEEP_AVG; | |
2903 | ||
2904 | /* | |
2905 | * Tasks charged proportionately less run_time at high sleep_avg to | |
2906 | * delay them losing their interactive status | |
2907 | */ | |
2908 | run_time /= (CURRENT_BONUS(prev) ? : 1); | |
2909 | ||
2910 | spin_lock_irq(&rq->lock); | |
2911 | ||
2912 | if (unlikely(prev->flags & PF_DEAD)) | |
2913 | prev->state = EXIT_DEAD; | |
2914 | ||
2915 | switch_count = &prev->nivcsw; | |
2916 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { | |
2917 | switch_count = &prev->nvcsw; | |
2918 | if (unlikely((prev->state & TASK_INTERRUPTIBLE) && | |
2919 | unlikely(signal_pending(prev)))) | |
2920 | prev->state = TASK_RUNNING; | |
2921 | else { | |
2922 | if (prev->state == TASK_UNINTERRUPTIBLE) | |
2923 | rq->nr_uninterruptible++; | |
2924 | deactivate_task(prev, rq); | |
2925 | } | |
2926 | } | |
2927 | ||
2928 | cpu = smp_processor_id(); | |
2929 | if (unlikely(!rq->nr_running)) { | |
1da177e4 LT |
2930 | idle_balance(cpu, rq); |
2931 | if (!rq->nr_running) { | |
2932 | next = rq->idle; | |
2933 | rq->expired_timestamp = 0; | |
c96d145e | 2934 | wake_sleeping_dependent(cpu); |
1da177e4 LT |
2935 | goto switch_tasks; |
2936 | } | |
1da177e4 LT |
2937 | } |
2938 | ||
2939 | array = rq->active; | |
2940 | if (unlikely(!array->nr_active)) { | |
2941 | /* | |
2942 | * Switch the active and expired arrays. | |
2943 | */ | |
2944 | schedstat_inc(rq, sched_switch); | |
2945 | rq->active = rq->expired; | |
2946 | rq->expired = array; | |
2947 | array = rq->active; | |
2948 | rq->expired_timestamp = 0; | |
2949 | rq->best_expired_prio = MAX_PRIO; | |
2950 | } | |
2951 | ||
2952 | idx = sched_find_first_bit(array->bitmap); | |
2953 | queue = array->queue + idx; | |
2954 | next = list_entry(queue->next, task_t, run_list); | |
2955 | ||
3dee386e | 2956 | if (!rt_task(next) && interactive_sleep(next->sleep_type)) { |
1da177e4 | 2957 | unsigned long long delta = now - next->timestamp; |
238628ed | 2958 | if (unlikely((long long)(now - next->timestamp) < 0)) |
1da177e4 LT |
2959 | delta = 0; |
2960 | ||
3dee386e | 2961 | if (next->sleep_type == SLEEP_INTERACTIVE) |
1da177e4 LT |
2962 | delta = delta * (ON_RUNQUEUE_WEIGHT * 128 / 100) / 128; |
2963 | ||
2964 | array = next->array; | |
a3464a10 CS |
2965 | new_prio = recalc_task_prio(next, next->timestamp + delta); |
2966 | ||
2967 | if (unlikely(next->prio != new_prio)) { | |
2968 | dequeue_task(next, array); | |
2969 | next->prio = new_prio; | |
2970 | enqueue_task(next, array); | |
7c4bb1f9 | 2971 | } |
1da177e4 | 2972 | } |
3dee386e | 2973 | next->sleep_type = SLEEP_NORMAL; |
c96d145e CK |
2974 | if (dependent_sleeper(cpu, rq, next)) |
2975 | next = rq->idle; | |
1da177e4 LT |
2976 | switch_tasks: |
2977 | if (next == rq->idle) | |
2978 | schedstat_inc(rq, sched_goidle); | |
2979 | prefetch(next); | |
383f2835 | 2980 | prefetch_stack(next); |
1da177e4 LT |
2981 | clear_tsk_need_resched(prev); |
2982 | rcu_qsctr_inc(task_cpu(prev)); | |
2983 | ||
2984 | update_cpu_clock(prev, rq, now); | |
2985 | ||
2986 | prev->sleep_avg -= run_time; | |
2987 | if ((long)prev->sleep_avg <= 0) | |
2988 | prev->sleep_avg = 0; | |
2989 | prev->timestamp = prev->last_ran = now; | |
2990 | ||
2991 | sched_info_switch(prev, next); | |
2992 | if (likely(prev != next)) { | |
2993 | next->timestamp = now; | |
2994 | rq->nr_switches++; | |
2995 | rq->curr = next; | |
2996 | ++*switch_count; | |
2997 | ||
4866cde0 | 2998 | prepare_task_switch(rq, next); |
1da177e4 LT |
2999 | prev = context_switch(rq, prev, next); |
3000 | barrier(); | |
4866cde0 NP |
3001 | /* |
3002 | * this_rq must be evaluated again because prev may have moved | |
3003 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
3004 | * frame will be invalid. | |
3005 | */ | |
3006 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
3007 | } else |
3008 | spin_unlock_irq(&rq->lock); | |
3009 | ||
3010 | prev = current; | |
3011 | if (unlikely(reacquire_kernel_lock(prev) < 0)) | |
3012 | goto need_resched_nonpreemptible; | |
3013 | preempt_enable_no_resched(); | |
3014 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3015 | goto need_resched; | |
3016 | } | |
3017 | ||
3018 | EXPORT_SYMBOL(schedule); | |
3019 | ||
3020 | #ifdef CONFIG_PREEMPT | |
3021 | /* | |
3022 | * this is is the entry point to schedule() from in-kernel preemption | |
3023 | * off of preempt_enable. Kernel preemptions off return from interrupt | |
3024 | * occur there and call schedule directly. | |
3025 | */ | |
3026 | asmlinkage void __sched preempt_schedule(void) | |
3027 | { | |
3028 | struct thread_info *ti = current_thread_info(); | |
3029 | #ifdef CONFIG_PREEMPT_BKL | |
3030 | struct task_struct *task = current; | |
3031 | int saved_lock_depth; | |
3032 | #endif | |
3033 | /* | |
3034 | * If there is a non-zero preempt_count or interrupts are disabled, | |
3035 | * we do not want to preempt the current task. Just return.. | |
3036 | */ | |
3037 | if (unlikely(ti->preempt_count || irqs_disabled())) | |
3038 | return; | |
3039 | ||
3040 | need_resched: | |
3041 | add_preempt_count(PREEMPT_ACTIVE); | |
3042 | /* | |
3043 | * We keep the big kernel semaphore locked, but we | |
3044 | * clear ->lock_depth so that schedule() doesnt | |
3045 | * auto-release the semaphore: | |
3046 | */ | |
3047 | #ifdef CONFIG_PREEMPT_BKL | |
3048 | saved_lock_depth = task->lock_depth; | |
3049 | task->lock_depth = -1; | |
3050 | #endif | |
3051 | schedule(); | |
3052 | #ifdef CONFIG_PREEMPT_BKL | |
3053 | task->lock_depth = saved_lock_depth; | |
3054 | #endif | |
3055 | sub_preempt_count(PREEMPT_ACTIVE); | |
3056 | ||
3057 | /* we could miss a preemption opportunity between schedule and now */ | |
3058 | barrier(); | |
3059 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3060 | goto need_resched; | |
3061 | } | |
3062 | ||
3063 | EXPORT_SYMBOL(preempt_schedule); | |
3064 | ||
3065 | /* | |
3066 | * this is is the entry point to schedule() from kernel preemption | |
3067 | * off of irq context. | |
3068 | * Note, that this is called and return with irqs disabled. This will | |
3069 | * protect us against recursive calling from irq. | |
3070 | */ | |
3071 | asmlinkage void __sched preempt_schedule_irq(void) | |
3072 | { | |
3073 | struct thread_info *ti = current_thread_info(); | |
3074 | #ifdef CONFIG_PREEMPT_BKL | |
3075 | struct task_struct *task = current; | |
3076 | int saved_lock_depth; | |
3077 | #endif | |
3078 | /* Catch callers which need to be fixed*/ | |
3079 | BUG_ON(ti->preempt_count || !irqs_disabled()); | |
3080 | ||
3081 | need_resched: | |
3082 | add_preempt_count(PREEMPT_ACTIVE); | |
3083 | /* | |
3084 | * We keep the big kernel semaphore locked, but we | |
3085 | * clear ->lock_depth so that schedule() doesnt | |
3086 | * auto-release the semaphore: | |
3087 | */ | |
3088 | #ifdef CONFIG_PREEMPT_BKL | |
3089 | saved_lock_depth = task->lock_depth; | |
3090 | task->lock_depth = -1; | |
3091 | #endif | |
3092 | local_irq_enable(); | |
3093 | schedule(); | |
3094 | local_irq_disable(); | |
3095 | #ifdef CONFIG_PREEMPT_BKL | |
3096 | task->lock_depth = saved_lock_depth; | |
3097 | #endif | |
3098 | sub_preempt_count(PREEMPT_ACTIVE); | |
3099 | ||
3100 | /* we could miss a preemption opportunity between schedule and now */ | |
3101 | barrier(); | |
3102 | if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) | |
3103 | goto need_resched; | |
3104 | } | |
3105 | ||
3106 | #endif /* CONFIG_PREEMPT */ | |
3107 | ||
95cdf3b7 IM |
3108 | int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
3109 | void *key) | |
1da177e4 | 3110 | { |
c43dc2fd | 3111 | task_t *p = curr->private; |
1da177e4 LT |
3112 | return try_to_wake_up(p, mode, sync); |
3113 | } | |
3114 | ||
3115 | EXPORT_SYMBOL(default_wake_function); | |
3116 | ||
3117 | /* | |
3118 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just | |
3119 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
3120 | * number) then we wake all the non-exclusive tasks and one exclusive task. | |
3121 | * | |
3122 | * There are circumstances in which we can try to wake a task which has already | |
3123 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns | |
3124 | * zero in this (rare) case, and we handle it by continuing to scan the queue. | |
3125 | */ | |
3126 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, | |
3127 | int nr_exclusive, int sync, void *key) | |
3128 | { | |
3129 | struct list_head *tmp, *next; | |
3130 | ||
3131 | list_for_each_safe(tmp, next, &q->task_list) { | |
3132 | wait_queue_t *curr; | |
3133 | unsigned flags; | |
3134 | curr = list_entry(tmp, wait_queue_t, task_list); | |
3135 | flags = curr->flags; | |
3136 | if (curr->func(curr, mode, sync, key) && | |
3137 | (flags & WQ_FLAG_EXCLUSIVE) && | |
3138 | !--nr_exclusive) | |
3139 | break; | |
3140 | } | |
3141 | } | |
3142 | ||
3143 | /** | |
3144 | * __wake_up - wake up threads blocked on a waitqueue. | |
3145 | * @q: the waitqueue | |
3146 | * @mode: which threads | |
3147 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 3148 | * @key: is directly passed to the wakeup function |
1da177e4 LT |
3149 | */ |
3150 | void fastcall __wake_up(wait_queue_head_t *q, unsigned int mode, | |
95cdf3b7 | 3151 | int nr_exclusive, void *key) |
1da177e4 LT |
3152 | { |
3153 | unsigned long flags; | |
3154 | ||
3155 | spin_lock_irqsave(&q->lock, flags); | |
3156 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
3157 | spin_unlock_irqrestore(&q->lock, flags); | |
3158 | } | |
3159 | ||
3160 | EXPORT_SYMBOL(__wake_up); | |
3161 | ||
3162 | /* | |
3163 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
3164 | */ | |
3165 | void fastcall __wake_up_locked(wait_queue_head_t *q, unsigned int mode) | |
3166 | { | |
3167 | __wake_up_common(q, mode, 1, 0, NULL); | |
3168 | } | |
3169 | ||
3170 | /** | |
67be2dd1 | 3171 | * __wake_up_sync - wake up threads blocked on a waitqueue. |
1da177e4 LT |
3172 | * @q: the waitqueue |
3173 | * @mode: which threads | |
3174 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
3175 | * | |
3176 | * The sync wakeup differs that the waker knows that it will schedule | |
3177 | * away soon, so while the target thread will be woken up, it will not | |
3178 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
3179 | * with each other. This can prevent needless bouncing between CPUs. | |
3180 | * | |
3181 | * On UP it can prevent extra preemption. | |
3182 | */ | |
95cdf3b7 IM |
3183 | void fastcall |
3184 | __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
1da177e4 LT |
3185 | { |
3186 | unsigned long flags; | |
3187 | int sync = 1; | |
3188 | ||
3189 | if (unlikely(!q)) | |
3190 | return; | |
3191 | ||
3192 | if (unlikely(!nr_exclusive)) | |
3193 | sync = 0; | |
3194 | ||
3195 | spin_lock_irqsave(&q->lock, flags); | |
3196 | __wake_up_common(q, mode, nr_exclusive, sync, NULL); | |
3197 | spin_unlock_irqrestore(&q->lock, flags); | |
3198 | } | |
3199 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ | |
3200 | ||
3201 | void fastcall complete(struct completion *x) | |
3202 | { | |
3203 | unsigned long flags; | |
3204 | ||
3205 | spin_lock_irqsave(&x->wait.lock, flags); | |
3206 | x->done++; | |
3207 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3208 | 1, 0, NULL); | |
3209 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3210 | } | |
3211 | EXPORT_SYMBOL(complete); | |
3212 | ||
3213 | void fastcall complete_all(struct completion *x) | |
3214 | { | |
3215 | unsigned long flags; | |
3216 | ||
3217 | spin_lock_irqsave(&x->wait.lock, flags); | |
3218 | x->done += UINT_MAX/2; | |
3219 | __wake_up_common(&x->wait, TASK_UNINTERRUPTIBLE | TASK_INTERRUPTIBLE, | |
3220 | 0, 0, NULL); | |
3221 | spin_unlock_irqrestore(&x->wait.lock, flags); | |
3222 | } | |
3223 | EXPORT_SYMBOL(complete_all); | |
3224 | ||
3225 | void fastcall __sched wait_for_completion(struct completion *x) | |
3226 | { | |
3227 | might_sleep(); | |
3228 | spin_lock_irq(&x->wait.lock); | |
3229 | if (!x->done) { | |
3230 | DECLARE_WAITQUEUE(wait, current); | |
3231 | ||
3232 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3233 | __add_wait_queue_tail(&x->wait, &wait); | |
3234 | do { | |
3235 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3236 | spin_unlock_irq(&x->wait.lock); | |
3237 | schedule(); | |
3238 | spin_lock_irq(&x->wait.lock); | |
3239 | } while (!x->done); | |
3240 | __remove_wait_queue(&x->wait, &wait); | |
3241 | } | |
3242 | x->done--; | |
3243 | spin_unlock_irq(&x->wait.lock); | |
3244 | } | |
3245 | EXPORT_SYMBOL(wait_for_completion); | |
3246 | ||
3247 | unsigned long fastcall __sched | |
3248 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) | |
3249 | { | |
3250 | might_sleep(); | |
3251 | ||
3252 | spin_lock_irq(&x->wait.lock); | |
3253 | if (!x->done) { | |
3254 | DECLARE_WAITQUEUE(wait, current); | |
3255 | ||
3256 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3257 | __add_wait_queue_tail(&x->wait, &wait); | |
3258 | do { | |
3259 | __set_current_state(TASK_UNINTERRUPTIBLE); | |
3260 | spin_unlock_irq(&x->wait.lock); | |
3261 | timeout = schedule_timeout(timeout); | |
3262 | spin_lock_irq(&x->wait.lock); | |
3263 | if (!timeout) { | |
3264 | __remove_wait_queue(&x->wait, &wait); | |
3265 | goto out; | |
3266 | } | |
3267 | } while (!x->done); | |
3268 | __remove_wait_queue(&x->wait, &wait); | |
3269 | } | |
3270 | x->done--; | |
3271 | out: | |
3272 | spin_unlock_irq(&x->wait.lock); | |
3273 | return timeout; | |
3274 | } | |
3275 | EXPORT_SYMBOL(wait_for_completion_timeout); | |
3276 | ||
3277 | int fastcall __sched wait_for_completion_interruptible(struct completion *x) | |
3278 | { | |
3279 | int ret = 0; | |
3280 | ||
3281 | might_sleep(); | |
3282 | ||
3283 | spin_lock_irq(&x->wait.lock); | |
3284 | if (!x->done) { | |
3285 | DECLARE_WAITQUEUE(wait, current); | |
3286 | ||
3287 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3288 | __add_wait_queue_tail(&x->wait, &wait); | |
3289 | do { | |
3290 | if (signal_pending(current)) { | |
3291 | ret = -ERESTARTSYS; | |
3292 | __remove_wait_queue(&x->wait, &wait); | |
3293 | goto out; | |
3294 | } | |
3295 | __set_current_state(TASK_INTERRUPTIBLE); | |
3296 | spin_unlock_irq(&x->wait.lock); | |
3297 | schedule(); | |
3298 | spin_lock_irq(&x->wait.lock); | |
3299 | } while (!x->done); | |
3300 | __remove_wait_queue(&x->wait, &wait); | |
3301 | } | |
3302 | x->done--; | |
3303 | out: | |
3304 | spin_unlock_irq(&x->wait.lock); | |
3305 | ||
3306 | return ret; | |
3307 | } | |
3308 | EXPORT_SYMBOL(wait_for_completion_interruptible); | |
3309 | ||
3310 | unsigned long fastcall __sched | |
3311 | wait_for_completion_interruptible_timeout(struct completion *x, | |
3312 | unsigned long timeout) | |
3313 | { | |
3314 | might_sleep(); | |
3315 | ||
3316 | spin_lock_irq(&x->wait.lock); | |
3317 | if (!x->done) { | |
3318 | DECLARE_WAITQUEUE(wait, current); | |
3319 | ||
3320 | wait.flags |= WQ_FLAG_EXCLUSIVE; | |
3321 | __add_wait_queue_tail(&x->wait, &wait); | |
3322 | do { | |
3323 | if (signal_pending(current)) { | |
3324 | timeout = -ERESTARTSYS; | |
3325 | __remove_wait_queue(&x->wait, &wait); | |
3326 | goto out; | |
3327 | } | |
3328 | __set_current_state(TASK_INTERRUPTIBLE); | |
3329 | spin_unlock_irq(&x->wait.lock); | |
3330 | timeout = schedule_timeout(timeout); | |
3331 | spin_lock_irq(&x->wait.lock); | |
3332 | if (!timeout) { | |
3333 | __remove_wait_queue(&x->wait, &wait); | |
3334 | goto out; | |
3335 | } | |
3336 | } while (!x->done); | |
3337 | __remove_wait_queue(&x->wait, &wait); | |
3338 | } | |
3339 | x->done--; | |
3340 | out: | |
3341 | spin_unlock_irq(&x->wait.lock); | |
3342 | return timeout; | |
3343 | } | |
3344 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); | |
3345 | ||
3346 | ||
3347 | #define SLEEP_ON_VAR \ | |
3348 | unsigned long flags; \ | |
3349 | wait_queue_t wait; \ | |
3350 | init_waitqueue_entry(&wait, current); | |
3351 | ||
3352 | #define SLEEP_ON_HEAD \ | |
3353 | spin_lock_irqsave(&q->lock,flags); \ | |
3354 | __add_wait_queue(q, &wait); \ | |
3355 | spin_unlock(&q->lock); | |
3356 | ||
3357 | #define SLEEP_ON_TAIL \ | |
3358 | spin_lock_irq(&q->lock); \ | |
3359 | __remove_wait_queue(q, &wait); \ | |
3360 | spin_unlock_irqrestore(&q->lock, flags); | |
3361 | ||
3362 | void fastcall __sched interruptible_sleep_on(wait_queue_head_t *q) | |
3363 | { | |
3364 | SLEEP_ON_VAR | |
3365 | ||
3366 | current->state = TASK_INTERRUPTIBLE; | |
3367 | ||
3368 | SLEEP_ON_HEAD | |
3369 | schedule(); | |
3370 | SLEEP_ON_TAIL | |
3371 | } | |
3372 | ||
3373 | EXPORT_SYMBOL(interruptible_sleep_on); | |
3374 | ||
95cdf3b7 IM |
3375 | long fastcall __sched |
3376 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) | |
1da177e4 LT |
3377 | { |
3378 | SLEEP_ON_VAR | |
3379 | ||
3380 | current->state = TASK_INTERRUPTIBLE; | |
3381 | ||
3382 | SLEEP_ON_HEAD | |
3383 | timeout = schedule_timeout(timeout); | |
3384 | SLEEP_ON_TAIL | |
3385 | ||
3386 | return timeout; | |
3387 | } | |
3388 | ||
3389 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); | |
3390 | ||
3391 | void fastcall __sched sleep_on(wait_queue_head_t *q) | |
3392 | { | |
3393 | SLEEP_ON_VAR | |
3394 | ||
3395 | current->state = TASK_UNINTERRUPTIBLE; | |
3396 | ||
3397 | SLEEP_ON_HEAD | |
3398 | schedule(); | |
3399 | SLEEP_ON_TAIL | |
3400 | } | |
3401 | ||
3402 | EXPORT_SYMBOL(sleep_on); | |
3403 | ||
3404 | long fastcall __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) | |
3405 | { | |
3406 | SLEEP_ON_VAR | |
3407 | ||
3408 | current->state = TASK_UNINTERRUPTIBLE; | |
3409 | ||
3410 | SLEEP_ON_HEAD | |
3411 | timeout = schedule_timeout(timeout); | |
3412 | SLEEP_ON_TAIL | |
3413 | ||
3414 | return timeout; | |
3415 | } | |
3416 | ||
3417 | EXPORT_SYMBOL(sleep_on_timeout); | |
3418 | ||
3419 | void set_user_nice(task_t *p, long nice) | |
3420 | { | |
3421 | unsigned long flags; | |
3422 | prio_array_t *array; | |
3423 | runqueue_t *rq; | |
3424 | int old_prio, new_prio, delta; | |
3425 | ||
3426 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
3427 | return; | |
3428 | /* | |
3429 | * We have to be careful, if called from sys_setpriority(), | |
3430 | * the task might be in the middle of scheduling on another CPU. | |
3431 | */ | |
3432 | rq = task_rq_lock(p, &flags); | |
3433 | /* | |
3434 | * The RT priorities are set via sched_setscheduler(), but we still | |
3435 | * allow the 'normal' nice value to be set - but as expected | |
3436 | * it wont have any effect on scheduling until the task is | |
b0a9499c | 3437 | * not SCHED_NORMAL/SCHED_BATCH: |
1da177e4 LT |
3438 | */ |
3439 | if (rt_task(p)) { | |
3440 | p->static_prio = NICE_TO_PRIO(nice); | |
3441 | goto out_unlock; | |
3442 | } | |
3443 | array = p->array; | |
a2000572 | 3444 | if (array) |
1da177e4 LT |
3445 | dequeue_task(p, array); |
3446 | ||
3447 | old_prio = p->prio; | |
3448 | new_prio = NICE_TO_PRIO(nice); | |
3449 | delta = new_prio - old_prio; | |
3450 | p->static_prio = NICE_TO_PRIO(nice); | |
3451 | p->prio += delta; | |
3452 | ||
3453 | if (array) { | |
3454 | enqueue_task(p, array); | |
3455 | /* | |
3456 | * If the task increased its priority or is running and | |
3457 | * lowered its priority, then reschedule its CPU: | |
3458 | */ | |
3459 | if (delta < 0 || (delta > 0 && task_running(rq, p))) | |
3460 | resched_task(rq->curr); | |
3461 | } | |
3462 | out_unlock: | |
3463 | task_rq_unlock(rq, &flags); | |
3464 | } | |
3465 | ||
3466 | EXPORT_SYMBOL(set_user_nice); | |
3467 | ||
e43379f1 MM |
3468 | /* |
3469 | * can_nice - check if a task can reduce its nice value | |
3470 | * @p: task | |
3471 | * @nice: nice value | |
3472 | */ | |
3473 | int can_nice(const task_t *p, const int nice) | |
3474 | { | |
024f4747 MM |
3475 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
3476 | int nice_rlim = 20 - nice; | |
e43379f1 MM |
3477 | return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
3478 | capable(CAP_SYS_NICE)); | |
3479 | } | |
3480 | ||
1da177e4 LT |
3481 | #ifdef __ARCH_WANT_SYS_NICE |
3482 | ||
3483 | /* | |
3484 | * sys_nice - change the priority of the current process. | |
3485 | * @increment: priority increment | |
3486 | * | |
3487 | * sys_setpriority is a more generic, but much slower function that | |
3488 | * does similar things. | |
3489 | */ | |
3490 | asmlinkage long sys_nice(int increment) | |
3491 | { | |
3492 | int retval; | |
3493 | long nice; | |
3494 | ||
3495 | /* | |
3496 | * Setpriority might change our priority at the same moment. | |
3497 | * We don't have to worry. Conceptually one call occurs first | |
3498 | * and we have a single winner. | |
3499 | */ | |
e43379f1 MM |
3500 | if (increment < -40) |
3501 | increment = -40; | |
1da177e4 LT |
3502 | if (increment > 40) |
3503 | increment = 40; | |
3504 | ||
3505 | nice = PRIO_TO_NICE(current->static_prio) + increment; | |
3506 | if (nice < -20) | |
3507 | nice = -20; | |
3508 | if (nice > 19) | |
3509 | nice = 19; | |
3510 | ||
e43379f1 MM |
3511 | if (increment < 0 && !can_nice(current, nice)) |
3512 | return -EPERM; | |
3513 | ||
1da177e4 LT |
3514 | retval = security_task_setnice(current, nice); |
3515 | if (retval) | |
3516 | return retval; | |
3517 | ||
3518 | set_user_nice(current, nice); | |
3519 | return 0; | |
3520 | } | |
3521 | ||
3522 | #endif | |
3523 | ||
3524 | /** | |
3525 | * task_prio - return the priority value of a given task. | |
3526 | * @p: the task in question. | |
3527 | * | |
3528 | * This is the priority value as seen by users in /proc. | |
3529 | * RT tasks are offset by -200. Normal tasks are centered | |
3530 | * around 0, value goes from -16 to +15. | |
3531 | */ | |
3532 | int task_prio(const task_t *p) | |
3533 | { | |
3534 | return p->prio - MAX_RT_PRIO; | |
3535 | } | |
3536 | ||
3537 | /** | |
3538 | * task_nice - return the nice value of a given task. | |
3539 | * @p: the task in question. | |
3540 | */ | |
3541 | int task_nice(const task_t *p) | |
3542 | { | |
3543 | return TASK_NICE(p); | |
3544 | } | |
1da177e4 | 3545 | EXPORT_SYMBOL_GPL(task_nice); |
1da177e4 LT |
3546 | |
3547 | /** | |
3548 | * idle_cpu - is a given cpu idle currently? | |
3549 | * @cpu: the processor in question. | |
3550 | */ | |
3551 | int idle_cpu(int cpu) | |
3552 | { | |
3553 | return cpu_curr(cpu) == cpu_rq(cpu)->idle; | |
3554 | } | |
3555 | ||
1da177e4 LT |
3556 | /** |
3557 | * idle_task - return the idle task for a given cpu. | |
3558 | * @cpu: the processor in question. | |
3559 | */ | |
3560 | task_t *idle_task(int cpu) | |
3561 | { | |
3562 | return cpu_rq(cpu)->idle; | |
3563 | } | |
3564 | ||
3565 | /** | |
3566 | * find_process_by_pid - find a process with a matching PID value. | |
3567 | * @pid: the pid in question. | |
3568 | */ | |
3569 | static inline task_t *find_process_by_pid(pid_t pid) | |
3570 | { | |
3571 | return pid ? find_task_by_pid(pid) : current; | |
3572 | } | |
3573 | ||
3574 | /* Actually do priority change: must hold rq lock. */ | |
3575 | static void __setscheduler(struct task_struct *p, int policy, int prio) | |
3576 | { | |
3577 | BUG_ON(p->array); | |
3578 | p->policy = policy; | |
3579 | p->rt_priority = prio; | |
b0a9499c | 3580 | if (policy != SCHED_NORMAL && policy != SCHED_BATCH) { |
d46523ea | 3581 | p->prio = MAX_RT_PRIO-1 - p->rt_priority; |
b0a9499c | 3582 | } else { |
1da177e4 | 3583 | p->prio = p->static_prio; |
b0a9499c IM |
3584 | /* |
3585 | * SCHED_BATCH tasks are treated as perpetual CPU hogs: | |
3586 | */ | |
3587 | if (policy == SCHED_BATCH) | |
3588 | p->sleep_avg = 0; | |
3589 | } | |
1da177e4 LT |
3590 | } |
3591 | ||
3592 | /** | |
3593 | * sched_setscheduler - change the scheduling policy and/or RT priority of | |
3594 | * a thread. | |
3595 | * @p: the task in question. | |
3596 | * @policy: new policy. | |
3597 | * @param: structure containing the new RT priority. | |
3598 | */ | |
95cdf3b7 IM |
3599 | int sched_setscheduler(struct task_struct *p, int policy, |
3600 | struct sched_param *param) | |
1da177e4 LT |
3601 | { |
3602 | int retval; | |
3603 | int oldprio, oldpolicy = -1; | |
3604 | prio_array_t *array; | |
3605 | unsigned long flags; | |
3606 | runqueue_t *rq; | |
3607 | ||
3608 | recheck: | |
3609 | /* double check policy once rq lock held */ | |
3610 | if (policy < 0) | |
3611 | policy = oldpolicy = p->policy; | |
3612 | else if (policy != SCHED_FIFO && policy != SCHED_RR && | |
b0a9499c IM |
3613 | policy != SCHED_NORMAL && policy != SCHED_BATCH) |
3614 | return -EINVAL; | |
1da177e4 LT |
3615 | /* |
3616 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
b0a9499c IM |
3617 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL and |
3618 | * SCHED_BATCH is 0. | |
1da177e4 LT |
3619 | */ |
3620 | if (param->sched_priority < 0 || | |
95cdf3b7 | 3621 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 3622 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 3623 | return -EINVAL; |
b0a9499c IM |
3624 | if ((policy == SCHED_NORMAL || policy == SCHED_BATCH) |
3625 | != (param->sched_priority == 0)) | |
1da177e4 LT |
3626 | return -EINVAL; |
3627 | ||
37e4ab3f OC |
3628 | /* |
3629 | * Allow unprivileged RT tasks to decrease priority: | |
3630 | */ | |
3631 | if (!capable(CAP_SYS_NICE)) { | |
b0a9499c IM |
3632 | /* |
3633 | * can't change policy, except between SCHED_NORMAL | |
3634 | * and SCHED_BATCH: | |
3635 | */ | |
3636 | if (((policy != SCHED_NORMAL && p->policy != SCHED_BATCH) && | |
3637 | (policy != SCHED_BATCH && p->policy != SCHED_NORMAL)) && | |
3638 | !p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) | |
37e4ab3f OC |
3639 | return -EPERM; |
3640 | /* can't increase priority */ | |
b0a9499c | 3641 | if ((policy != SCHED_NORMAL && policy != SCHED_BATCH) && |
37e4ab3f OC |
3642 | param->sched_priority > p->rt_priority && |
3643 | param->sched_priority > | |
3644 | p->signal->rlim[RLIMIT_RTPRIO].rlim_cur) | |
3645 | return -EPERM; | |
3646 | /* can't change other user's priorities */ | |
3647 | if ((current->euid != p->euid) && | |
3648 | (current->euid != p->uid)) | |
3649 | return -EPERM; | |
3650 | } | |
1da177e4 LT |
3651 | |
3652 | retval = security_task_setscheduler(p, policy, param); | |
3653 | if (retval) | |
3654 | return retval; | |
3655 | /* | |
3656 | * To be able to change p->policy safely, the apropriate | |
3657 | * runqueue lock must be held. | |
3658 | */ | |
3659 | rq = task_rq_lock(p, &flags); | |
3660 | /* recheck policy now with rq lock held */ | |
3661 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
3662 | policy = oldpolicy = -1; | |
3663 | task_rq_unlock(rq, &flags); | |
3664 | goto recheck; | |
3665 | } | |
3666 | array = p->array; | |
3667 | if (array) | |
3668 | deactivate_task(p, rq); | |
3669 | oldprio = p->prio; | |
3670 | __setscheduler(p, policy, param->sched_priority); | |
3671 | if (array) { | |
3672 | __activate_task(p, rq); | |
3673 | /* | |
3674 | * Reschedule if we are currently running on this runqueue and | |
3675 | * our priority decreased, or if we are not currently running on | |
3676 | * this runqueue and our priority is higher than the current's | |
3677 | */ | |
3678 | if (task_running(rq, p)) { | |
3679 | if (p->prio > oldprio) | |
3680 | resched_task(rq->curr); | |
3681 | } else if (TASK_PREEMPTS_CURR(p, rq)) | |
3682 | resched_task(rq->curr); | |
3683 | } | |
3684 | task_rq_unlock(rq, &flags); | |
3685 | return 0; | |
3686 | } | |
3687 | EXPORT_SYMBOL_GPL(sched_setscheduler); | |
3688 | ||
95cdf3b7 IM |
3689 | static int |
3690 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 LT |
3691 | { |
3692 | int retval; | |
3693 | struct sched_param lparam; | |
3694 | struct task_struct *p; | |
3695 | ||
3696 | if (!param || pid < 0) | |
3697 | return -EINVAL; | |
3698 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
3699 | return -EFAULT; | |
3700 | read_lock_irq(&tasklist_lock); | |
3701 | p = find_process_by_pid(pid); | |
3702 | if (!p) { | |
3703 | read_unlock_irq(&tasklist_lock); | |
3704 | return -ESRCH; | |
3705 | } | |
3706 | retval = sched_setscheduler(p, policy, &lparam); | |
3707 | read_unlock_irq(&tasklist_lock); | |
3708 | return retval; | |
3709 | } | |
3710 | ||
3711 | /** | |
3712 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
3713 | * @pid: the pid in question. | |
3714 | * @policy: new policy. | |
3715 | * @param: structure containing the new RT priority. | |
3716 | */ | |
3717 | asmlinkage long sys_sched_setscheduler(pid_t pid, int policy, | |
3718 | struct sched_param __user *param) | |
3719 | { | |
c21761f1 JB |
3720 | /* negative values for policy are not valid */ |
3721 | if (policy < 0) | |
3722 | return -EINVAL; | |
3723 | ||
1da177e4 LT |
3724 | return do_sched_setscheduler(pid, policy, param); |
3725 | } | |
3726 | ||
3727 | /** | |
3728 | * sys_sched_setparam - set/change the RT priority of a thread | |
3729 | * @pid: the pid in question. | |
3730 | * @param: structure containing the new RT priority. | |
3731 | */ | |
3732 | asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) | |
3733 | { | |
3734 | return do_sched_setscheduler(pid, -1, param); | |
3735 | } | |
3736 | ||
3737 | /** | |
3738 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
3739 | * @pid: the pid in question. | |
3740 | */ | |
3741 | asmlinkage long sys_sched_getscheduler(pid_t pid) | |
3742 | { | |
3743 | int retval = -EINVAL; | |
3744 | task_t *p; | |
3745 | ||
3746 | if (pid < 0) | |
3747 | goto out_nounlock; | |
3748 | ||
3749 | retval = -ESRCH; | |
3750 | read_lock(&tasklist_lock); | |
3751 | p = find_process_by_pid(pid); | |
3752 | if (p) { | |
3753 | retval = security_task_getscheduler(p); | |
3754 | if (!retval) | |
3755 | retval = p->policy; | |
3756 | } | |
3757 | read_unlock(&tasklist_lock); | |
3758 | ||
3759 | out_nounlock: | |
3760 | return retval; | |
3761 | } | |
3762 | ||
3763 | /** | |
3764 | * sys_sched_getscheduler - get the RT priority of a thread | |
3765 | * @pid: the pid in question. | |
3766 | * @param: structure containing the RT priority. | |
3767 | */ | |
3768 | asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) | |
3769 | { | |
3770 | struct sched_param lp; | |
3771 | int retval = -EINVAL; | |
3772 | task_t *p; | |
3773 | ||
3774 | if (!param || pid < 0) | |
3775 | goto out_nounlock; | |
3776 | ||
3777 | read_lock(&tasklist_lock); | |
3778 | p = find_process_by_pid(pid); | |
3779 | retval = -ESRCH; | |
3780 | if (!p) | |
3781 | goto out_unlock; | |
3782 | ||
3783 | retval = security_task_getscheduler(p); | |
3784 | if (retval) | |
3785 | goto out_unlock; | |
3786 | ||
3787 | lp.sched_priority = p->rt_priority; | |
3788 | read_unlock(&tasklist_lock); | |
3789 | ||
3790 | /* | |
3791 | * This one might sleep, we cannot do it with a spinlock held ... | |
3792 | */ | |
3793 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
3794 | ||
3795 | out_nounlock: | |
3796 | return retval; | |
3797 | ||
3798 | out_unlock: | |
3799 | read_unlock(&tasklist_lock); | |
3800 | return retval; | |
3801 | } | |
3802 | ||
3803 | long sched_setaffinity(pid_t pid, cpumask_t new_mask) | |
3804 | { | |
3805 | task_t *p; | |
3806 | int retval; | |
3807 | cpumask_t cpus_allowed; | |
3808 | ||
3809 | lock_cpu_hotplug(); | |
3810 | read_lock(&tasklist_lock); | |
3811 | ||
3812 | p = find_process_by_pid(pid); | |
3813 | if (!p) { | |
3814 | read_unlock(&tasklist_lock); | |
3815 | unlock_cpu_hotplug(); | |
3816 | return -ESRCH; | |
3817 | } | |
3818 | ||
3819 | /* | |
3820 | * It is not safe to call set_cpus_allowed with the | |
3821 | * tasklist_lock held. We will bump the task_struct's | |
3822 | * usage count and then drop tasklist_lock. | |
3823 | */ | |
3824 | get_task_struct(p); | |
3825 | read_unlock(&tasklist_lock); | |
3826 | ||
3827 | retval = -EPERM; | |
3828 | if ((current->euid != p->euid) && (current->euid != p->uid) && | |
3829 | !capable(CAP_SYS_NICE)) | |
3830 | goto out_unlock; | |
3831 | ||
e7834f8f DQ |
3832 | retval = security_task_setscheduler(p, 0, NULL); |
3833 | if (retval) | |
3834 | goto out_unlock; | |
3835 | ||
1da177e4 LT |
3836 | cpus_allowed = cpuset_cpus_allowed(p); |
3837 | cpus_and(new_mask, new_mask, cpus_allowed); | |
3838 | retval = set_cpus_allowed(p, new_mask); | |
3839 | ||
3840 | out_unlock: | |
3841 | put_task_struct(p); | |
3842 | unlock_cpu_hotplug(); | |
3843 | return retval; | |
3844 | } | |
3845 | ||
3846 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
3847 | cpumask_t *new_mask) | |
3848 | { | |
3849 | if (len < sizeof(cpumask_t)) { | |
3850 | memset(new_mask, 0, sizeof(cpumask_t)); | |
3851 | } else if (len > sizeof(cpumask_t)) { | |
3852 | len = sizeof(cpumask_t); | |
3853 | } | |
3854 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; | |
3855 | } | |
3856 | ||
3857 | /** | |
3858 | * sys_sched_setaffinity - set the cpu affinity of a process | |
3859 | * @pid: pid of the process | |
3860 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
3861 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
3862 | */ | |
3863 | asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, | |
3864 | unsigned long __user *user_mask_ptr) | |
3865 | { | |
3866 | cpumask_t new_mask; | |
3867 | int retval; | |
3868 | ||
3869 | retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); | |
3870 | if (retval) | |
3871 | return retval; | |
3872 | ||
3873 | return sched_setaffinity(pid, new_mask); | |
3874 | } | |
3875 | ||
3876 | /* | |
3877 | * Represents all cpu's present in the system | |
3878 | * In systems capable of hotplug, this map could dynamically grow | |
3879 | * as new cpu's are detected in the system via any platform specific | |
3880 | * method, such as ACPI for e.g. | |
3881 | */ | |
3882 | ||
4cef0c61 | 3883 | cpumask_t cpu_present_map __read_mostly; |
1da177e4 LT |
3884 | EXPORT_SYMBOL(cpu_present_map); |
3885 | ||
3886 | #ifndef CONFIG_SMP | |
4cef0c61 AK |
3887 | cpumask_t cpu_online_map __read_mostly = CPU_MASK_ALL; |
3888 | cpumask_t cpu_possible_map __read_mostly = CPU_MASK_ALL; | |
1da177e4 LT |
3889 | #endif |
3890 | ||
3891 | long sched_getaffinity(pid_t pid, cpumask_t *mask) | |
3892 | { | |
3893 | int retval; | |
3894 | task_t *p; | |
3895 | ||
3896 | lock_cpu_hotplug(); | |
3897 | read_lock(&tasklist_lock); | |
3898 | ||
3899 | retval = -ESRCH; | |
3900 | p = find_process_by_pid(pid); | |
3901 | if (!p) | |
3902 | goto out_unlock; | |
3903 | ||
e7834f8f DQ |
3904 | retval = security_task_getscheduler(p); |
3905 | if (retval) | |
3906 | goto out_unlock; | |
3907 | ||
2f7016d9 | 3908 | cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
1da177e4 LT |
3909 | |
3910 | out_unlock: | |
3911 | read_unlock(&tasklist_lock); | |
3912 | unlock_cpu_hotplug(); | |
3913 | if (retval) | |
3914 | return retval; | |
3915 | ||
3916 | return 0; | |
3917 | } | |
3918 | ||
3919 | /** | |
3920 | * sys_sched_getaffinity - get the cpu affinity of a process | |
3921 | * @pid: pid of the process | |
3922 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
3923 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
3924 | */ | |
3925 | asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, | |
3926 | unsigned long __user *user_mask_ptr) | |
3927 | { | |
3928 | int ret; | |
3929 | cpumask_t mask; | |
3930 | ||
3931 | if (len < sizeof(cpumask_t)) | |
3932 | return -EINVAL; | |
3933 | ||
3934 | ret = sched_getaffinity(pid, &mask); | |
3935 | if (ret < 0) | |
3936 | return ret; | |
3937 | ||
3938 | if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) | |
3939 | return -EFAULT; | |
3940 | ||
3941 | return sizeof(cpumask_t); | |
3942 | } | |
3943 | ||
3944 | /** | |
3945 | * sys_sched_yield - yield the current processor to other threads. | |
3946 | * | |
3947 | * this function yields the current CPU by moving the calling thread | |
3948 | * to the expired array. If there are no other threads running on this | |
3949 | * CPU then this function will return. | |
3950 | */ | |
3951 | asmlinkage long sys_sched_yield(void) | |
3952 | { | |
3953 | runqueue_t *rq = this_rq_lock(); | |
3954 | prio_array_t *array = current->array; | |
3955 | prio_array_t *target = rq->expired; | |
3956 | ||
3957 | schedstat_inc(rq, yld_cnt); | |
3958 | /* | |
3959 | * We implement yielding by moving the task into the expired | |
3960 | * queue. | |
3961 | * | |
3962 | * (special rule: RT tasks will just roundrobin in the active | |
3963 | * array.) | |
3964 | */ | |
3965 | if (rt_task(current)) | |
3966 | target = rq->active; | |
3967 | ||
5927ad78 | 3968 | if (array->nr_active == 1) { |
1da177e4 LT |
3969 | schedstat_inc(rq, yld_act_empty); |
3970 | if (!rq->expired->nr_active) | |
3971 | schedstat_inc(rq, yld_both_empty); | |
3972 | } else if (!rq->expired->nr_active) | |
3973 | schedstat_inc(rq, yld_exp_empty); | |
3974 | ||
3975 | if (array != target) { | |
3976 | dequeue_task(current, array); | |
3977 | enqueue_task(current, target); | |
3978 | } else | |
3979 | /* | |
3980 | * requeue_task is cheaper so perform that if possible. | |
3981 | */ | |
3982 | requeue_task(current, array); | |
3983 | ||
3984 | /* | |
3985 | * Since we are going to call schedule() anyway, there's | |
3986 | * no need to preempt or enable interrupts: | |
3987 | */ | |
3988 | __release(rq->lock); | |
3989 | _raw_spin_unlock(&rq->lock); | |
3990 | preempt_enable_no_resched(); | |
3991 | ||
3992 | schedule(); | |
3993 | ||
3994 | return 0; | |
3995 | } | |
3996 | ||
3997 | static inline void __cond_resched(void) | |
3998 | { | |
8e0a43d8 IM |
3999 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
4000 | __might_sleep(__FILE__, __LINE__); | |
4001 | #endif | |
5bbcfd90 IM |
4002 | /* |
4003 | * The BKS might be reacquired before we have dropped | |
4004 | * PREEMPT_ACTIVE, which could trigger a second | |
4005 | * cond_resched() call. | |
4006 | */ | |
4007 | if (unlikely(preempt_count())) | |
4008 | return; | |
8ba7b0a1 LT |
4009 | if (unlikely(system_state != SYSTEM_RUNNING)) |
4010 | return; | |
1da177e4 LT |
4011 | do { |
4012 | add_preempt_count(PREEMPT_ACTIVE); | |
4013 | schedule(); | |
4014 | sub_preempt_count(PREEMPT_ACTIVE); | |
4015 | } while (need_resched()); | |
4016 | } | |
4017 | ||
4018 | int __sched cond_resched(void) | |
4019 | { | |
4020 | if (need_resched()) { | |
4021 | __cond_resched(); | |
4022 | return 1; | |
4023 | } | |
4024 | return 0; | |
4025 | } | |
4026 | ||
4027 | EXPORT_SYMBOL(cond_resched); | |
4028 | ||
4029 | /* | |
4030 | * cond_resched_lock() - if a reschedule is pending, drop the given lock, | |
4031 | * call schedule, and on return reacquire the lock. | |
4032 | * | |
4033 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level | |
4034 | * operations here to prevent schedule() from being called twice (once via | |
4035 | * spin_unlock(), once by hand). | |
4036 | */ | |
95cdf3b7 | 4037 | int cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4038 | { |
6df3cecb JK |
4039 | int ret = 0; |
4040 | ||
1da177e4 LT |
4041 | if (need_lockbreak(lock)) { |
4042 | spin_unlock(lock); | |
4043 | cpu_relax(); | |
6df3cecb | 4044 | ret = 1; |
1da177e4 LT |
4045 | spin_lock(lock); |
4046 | } | |
4047 | if (need_resched()) { | |
4048 | _raw_spin_unlock(lock); | |
4049 | preempt_enable_no_resched(); | |
4050 | __cond_resched(); | |
6df3cecb | 4051 | ret = 1; |
1da177e4 | 4052 | spin_lock(lock); |
1da177e4 | 4053 | } |
6df3cecb | 4054 | return ret; |
1da177e4 LT |
4055 | } |
4056 | ||
4057 | EXPORT_SYMBOL(cond_resched_lock); | |
4058 | ||
4059 | int __sched cond_resched_softirq(void) | |
4060 | { | |
4061 | BUG_ON(!in_softirq()); | |
4062 | ||
4063 | if (need_resched()) { | |
4064 | __local_bh_enable(); | |
4065 | __cond_resched(); | |
4066 | local_bh_disable(); | |
4067 | return 1; | |
4068 | } | |
4069 | return 0; | |
4070 | } | |
4071 | ||
4072 | EXPORT_SYMBOL(cond_resched_softirq); | |
4073 | ||
4074 | ||
4075 | /** | |
4076 | * yield - yield the current processor to other threads. | |
4077 | * | |
4078 | * this is a shortcut for kernel-space yielding - it marks the | |
4079 | * thread runnable and calls sys_sched_yield(). | |
4080 | */ | |
4081 | void __sched yield(void) | |
4082 | { | |
4083 | set_current_state(TASK_RUNNING); | |
4084 | sys_sched_yield(); | |
4085 | } | |
4086 | ||
4087 | EXPORT_SYMBOL(yield); | |
4088 | ||
4089 | /* | |
4090 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so | |
4091 | * that process accounting knows that this is a task in IO wait state. | |
4092 | * | |
4093 | * But don't do that if it is a deliberate, throttling IO wait (this task | |
4094 | * has set its backing_dev_info: the queue against which it should throttle) | |
4095 | */ | |
4096 | void __sched io_schedule(void) | |
4097 | { | |
bfe5d834 | 4098 | struct runqueue *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4099 | |
4100 | atomic_inc(&rq->nr_iowait); | |
4101 | schedule(); | |
4102 | atomic_dec(&rq->nr_iowait); | |
4103 | } | |
4104 | ||
4105 | EXPORT_SYMBOL(io_schedule); | |
4106 | ||
4107 | long __sched io_schedule_timeout(long timeout) | |
4108 | { | |
bfe5d834 | 4109 | struct runqueue *rq = &__raw_get_cpu_var(runqueues); |
1da177e4 LT |
4110 | long ret; |
4111 | ||
4112 | atomic_inc(&rq->nr_iowait); | |
4113 | ret = schedule_timeout(timeout); | |
4114 | atomic_dec(&rq->nr_iowait); | |
4115 | return ret; | |
4116 | } | |
4117 | ||
4118 | /** | |
4119 | * sys_sched_get_priority_max - return maximum RT priority. | |
4120 | * @policy: scheduling class. | |
4121 | * | |
4122 | * this syscall returns the maximum rt_priority that can be used | |
4123 | * by a given scheduling class. | |
4124 | */ | |
4125 | asmlinkage long sys_sched_get_priority_max(int policy) | |
4126 | { | |
4127 | int ret = -EINVAL; | |
4128 | ||
4129 | switch (policy) { | |
4130 | case SCHED_FIFO: | |
4131 | case SCHED_RR: | |
4132 | ret = MAX_USER_RT_PRIO-1; | |
4133 | break; | |
4134 | case SCHED_NORMAL: | |
b0a9499c | 4135 | case SCHED_BATCH: |
1da177e4 LT |
4136 | ret = 0; |
4137 | break; | |
4138 | } | |
4139 | return ret; | |
4140 | } | |
4141 | ||
4142 | /** | |
4143 | * sys_sched_get_priority_min - return minimum RT priority. | |
4144 | * @policy: scheduling class. | |
4145 | * | |
4146 | * this syscall returns the minimum rt_priority that can be used | |
4147 | * by a given scheduling class. | |
4148 | */ | |
4149 | asmlinkage long sys_sched_get_priority_min(int policy) | |
4150 | { | |
4151 | int ret = -EINVAL; | |
4152 | ||
4153 | switch (policy) { | |
4154 | case SCHED_FIFO: | |
4155 | case SCHED_RR: | |
4156 | ret = 1; | |
4157 | break; | |
4158 | case SCHED_NORMAL: | |
b0a9499c | 4159 | case SCHED_BATCH: |
1da177e4 LT |
4160 | ret = 0; |
4161 | } | |
4162 | return ret; | |
4163 | } | |
4164 | ||
4165 | /** | |
4166 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4167 | * @pid: pid of the process. | |
4168 | * @interval: userspace pointer to the timeslice value. | |
4169 | * | |
4170 | * this syscall writes the default timeslice value of a given process | |
4171 | * into the user-space timespec buffer. A value of '0' means infinity. | |
4172 | */ | |
4173 | asmlinkage | |
4174 | long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) | |
4175 | { | |
4176 | int retval = -EINVAL; | |
4177 | struct timespec t; | |
4178 | task_t *p; | |
4179 | ||
4180 | if (pid < 0) | |
4181 | goto out_nounlock; | |
4182 | ||
4183 | retval = -ESRCH; | |
4184 | read_lock(&tasklist_lock); | |
4185 | p = find_process_by_pid(pid); | |
4186 | if (!p) | |
4187 | goto out_unlock; | |
4188 | ||
4189 | retval = security_task_getscheduler(p); | |
4190 | if (retval) | |
4191 | goto out_unlock; | |
4192 | ||
b78709cf | 4193 | jiffies_to_timespec(p->policy == SCHED_FIFO ? |
1da177e4 LT |
4194 | 0 : task_timeslice(p), &t); |
4195 | read_unlock(&tasklist_lock); | |
4196 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; | |
4197 | out_nounlock: | |
4198 | return retval; | |
4199 | out_unlock: | |
4200 | read_unlock(&tasklist_lock); | |
4201 | return retval; | |
4202 | } | |
4203 | ||
4204 | static inline struct task_struct *eldest_child(struct task_struct *p) | |
4205 | { | |
4206 | if (list_empty(&p->children)) return NULL; | |
4207 | return list_entry(p->children.next,struct task_struct,sibling); | |
4208 | } | |
4209 | ||
4210 | static inline struct task_struct *older_sibling(struct task_struct *p) | |
4211 | { | |
4212 | if (p->sibling.prev==&p->parent->children) return NULL; | |
4213 | return list_entry(p->sibling.prev,struct task_struct,sibling); | |
4214 | } | |
4215 | ||
4216 | static inline struct task_struct *younger_sibling(struct task_struct *p) | |
4217 | { | |
4218 | if (p->sibling.next==&p->parent->children) return NULL; | |
4219 | return list_entry(p->sibling.next,struct task_struct,sibling); | |
4220 | } | |
4221 | ||
95cdf3b7 | 4222 | static void show_task(task_t *p) |
1da177e4 LT |
4223 | { |
4224 | task_t *relative; | |
4225 | unsigned state; | |
4226 | unsigned long free = 0; | |
4227 | static const char *stat_nam[] = { "R", "S", "D", "T", "t", "Z", "X" }; | |
4228 | ||
4229 | printk("%-13.13s ", p->comm); | |
4230 | state = p->state ? __ffs(p->state) + 1 : 0; | |
4231 | if (state < ARRAY_SIZE(stat_nam)) | |
4232 | printk(stat_nam[state]); | |
4233 | else | |
4234 | printk("?"); | |
4235 | #if (BITS_PER_LONG == 32) | |
4236 | if (state == TASK_RUNNING) | |
4237 | printk(" running "); | |
4238 | else | |
4239 | printk(" %08lX ", thread_saved_pc(p)); | |
4240 | #else | |
4241 | if (state == TASK_RUNNING) | |
4242 | printk(" running task "); | |
4243 | else | |
4244 | printk(" %016lx ", thread_saved_pc(p)); | |
4245 | #endif | |
4246 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
4247 | { | |
10ebffde | 4248 | unsigned long *n = end_of_stack(p); |
1da177e4 LT |
4249 | while (!*n) |
4250 | n++; | |
10ebffde | 4251 | free = (unsigned long)n - (unsigned long)end_of_stack(p); |
1da177e4 LT |
4252 | } |
4253 | #endif | |
4254 | printk("%5lu %5d %6d ", free, p->pid, p->parent->pid); | |
4255 | if ((relative = eldest_child(p))) | |
4256 | printk("%5d ", relative->pid); | |
4257 | else | |
4258 | printk(" "); | |
4259 | if ((relative = younger_sibling(p))) | |
4260 | printk("%7d", relative->pid); | |
4261 | else | |
4262 | printk(" "); | |
4263 | if ((relative = older_sibling(p))) | |
4264 | printk(" %5d", relative->pid); | |
4265 | else | |
4266 | printk(" "); | |
4267 | if (!p->mm) | |
4268 | printk(" (L-TLB)\n"); | |
4269 | else | |
4270 | printk(" (NOTLB)\n"); | |
4271 | ||
4272 | if (state != TASK_RUNNING) | |
4273 | show_stack(p, NULL); | |
4274 | } | |
4275 | ||
4276 | void show_state(void) | |
4277 | { | |
4278 | task_t *g, *p; | |
4279 | ||
4280 | #if (BITS_PER_LONG == 32) | |
4281 | printk("\n" | |
4282 | " sibling\n"); | |
4283 | printk(" task PC pid father child younger older\n"); | |
4284 | #else | |
4285 | printk("\n" | |
4286 | " sibling\n"); | |
4287 | printk(" task PC pid father child younger older\n"); | |
4288 | #endif | |
4289 | read_lock(&tasklist_lock); | |
4290 | do_each_thread(g, p) { | |
4291 | /* | |
4292 | * reset the NMI-timeout, listing all files on a slow | |
4293 | * console might take alot of time: | |
4294 | */ | |
4295 | touch_nmi_watchdog(); | |
4296 | show_task(p); | |
4297 | } while_each_thread(g, p); | |
4298 | ||
4299 | read_unlock(&tasklist_lock); | |
de5097c2 | 4300 | mutex_debug_show_all_locks(); |
1da177e4 LT |
4301 | } |
4302 | ||
f340c0d1 IM |
4303 | /** |
4304 | * init_idle - set up an idle thread for a given CPU | |
4305 | * @idle: task in question | |
4306 | * @cpu: cpu the idle task belongs to | |
4307 | * | |
4308 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4309 | * flag, to make booting more robust. | |
4310 | */ | |
1da177e4 LT |
4311 | void __devinit init_idle(task_t *idle, int cpu) |
4312 | { | |
4313 | runqueue_t *rq = cpu_rq(cpu); | |
4314 | unsigned long flags; | |
4315 | ||
81c29a85 | 4316 | idle->timestamp = sched_clock(); |
1da177e4 LT |
4317 | idle->sleep_avg = 0; |
4318 | idle->array = NULL; | |
4319 | idle->prio = MAX_PRIO; | |
4320 | idle->state = TASK_RUNNING; | |
4321 | idle->cpus_allowed = cpumask_of_cpu(cpu); | |
4322 | set_task_cpu(idle, cpu); | |
4323 | ||
4324 | spin_lock_irqsave(&rq->lock, flags); | |
4325 | rq->curr = rq->idle = idle; | |
4866cde0 NP |
4326 | #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
4327 | idle->oncpu = 1; | |
4328 | #endif | |
1da177e4 LT |
4329 | spin_unlock_irqrestore(&rq->lock, flags); |
4330 | ||
4331 | /* Set the preempt count _outside_ the spinlocks! */ | |
4332 | #if defined(CONFIG_PREEMPT) && !defined(CONFIG_PREEMPT_BKL) | |
a1261f54 | 4333 | task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
1da177e4 | 4334 | #else |
a1261f54 | 4335 | task_thread_info(idle)->preempt_count = 0; |
1da177e4 LT |
4336 | #endif |
4337 | } | |
4338 | ||
4339 | /* | |
4340 | * In a system that switches off the HZ timer nohz_cpu_mask | |
4341 | * indicates which cpus entered this state. This is used | |
4342 | * in the rcu update to wait only for active cpus. For system | |
4343 | * which do not switch off the HZ timer nohz_cpu_mask should | |
4344 | * always be CPU_MASK_NONE. | |
4345 | */ | |
4346 | cpumask_t nohz_cpu_mask = CPU_MASK_NONE; | |
4347 | ||
4348 | #ifdef CONFIG_SMP | |
4349 | /* | |
4350 | * This is how migration works: | |
4351 | * | |
4352 | * 1) we queue a migration_req_t structure in the source CPU's | |
4353 | * runqueue and wake up that CPU's migration thread. | |
4354 | * 2) we down() the locked semaphore => thread blocks. | |
4355 | * 3) migration thread wakes up (implicitly it forces the migrated | |
4356 | * thread off the CPU) | |
4357 | * 4) it gets the migration request and checks whether the migrated | |
4358 | * task is still in the wrong runqueue. | |
4359 | * 5) if it's in the wrong runqueue then the migration thread removes | |
4360 | * it and puts it into the right queue. | |
4361 | * 6) migration thread up()s the semaphore. | |
4362 | * 7) we wake up and the migration is done. | |
4363 | */ | |
4364 | ||
4365 | /* | |
4366 | * Change a given task's CPU affinity. Migrate the thread to a | |
4367 | * proper CPU and schedule it away if the CPU it's executing on | |
4368 | * is removed from the allowed bitmask. | |
4369 | * | |
4370 | * NOTE: the caller must have a valid reference to the task, the | |
4371 | * task must not exit() & deallocate itself prematurely. The | |
4372 | * call is not atomic; no spinlocks may be held. | |
4373 | */ | |
4374 | int set_cpus_allowed(task_t *p, cpumask_t new_mask) | |
4375 | { | |
4376 | unsigned long flags; | |
4377 | int ret = 0; | |
4378 | migration_req_t req; | |
4379 | runqueue_t *rq; | |
4380 | ||
4381 | rq = task_rq_lock(p, &flags); | |
4382 | if (!cpus_intersects(new_mask, cpu_online_map)) { | |
4383 | ret = -EINVAL; | |
4384 | goto out; | |
4385 | } | |
4386 | ||
4387 | p->cpus_allowed = new_mask; | |
4388 | /* Can the task run on the task's current CPU? If so, we're done */ | |
4389 | if (cpu_isset(task_cpu(p), new_mask)) | |
4390 | goto out; | |
4391 | ||
4392 | if (migrate_task(p, any_online_cpu(new_mask), &req)) { | |
4393 | /* Need help from migration thread: drop lock and wait. */ | |
4394 | task_rq_unlock(rq, &flags); | |
4395 | wake_up_process(rq->migration_thread); | |
4396 | wait_for_completion(&req.done); | |
4397 | tlb_migrate_finish(p->mm); | |
4398 | return 0; | |
4399 | } | |
4400 | out: | |
4401 | task_rq_unlock(rq, &flags); | |
4402 | return ret; | |
4403 | } | |
4404 | ||
4405 | EXPORT_SYMBOL_GPL(set_cpus_allowed); | |
4406 | ||
4407 | /* | |
4408 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
4409 | * this because either it can't run here any more (set_cpus_allowed() | |
4410 | * away from this CPU, or CPU going down), or because we're | |
4411 | * attempting to rebalance this task on exec (sched_exec). | |
4412 | * | |
4413 | * So we race with normal scheduler movements, but that's OK, as long | |
4414 | * as the task is no longer on this CPU. | |
efc30814 KK |
4415 | * |
4416 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4417 | */ |
efc30814 | 4418 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 LT |
4419 | { |
4420 | runqueue_t *rq_dest, *rq_src; | |
efc30814 | 4421 | int ret = 0; |
1da177e4 LT |
4422 | |
4423 | if (unlikely(cpu_is_offline(dest_cpu))) | |
efc30814 | 4424 | return ret; |
1da177e4 LT |
4425 | |
4426 | rq_src = cpu_rq(src_cpu); | |
4427 | rq_dest = cpu_rq(dest_cpu); | |
4428 | ||
4429 | double_rq_lock(rq_src, rq_dest); | |
4430 | /* Already moved. */ | |
4431 | if (task_cpu(p) != src_cpu) | |
4432 | goto out; | |
4433 | /* Affinity changed (again). */ | |
4434 | if (!cpu_isset(dest_cpu, p->cpus_allowed)) | |
4435 | goto out; | |
4436 | ||
4437 | set_task_cpu(p, dest_cpu); | |
4438 | if (p->array) { | |
4439 | /* | |
4440 | * Sync timestamp with rq_dest's before activating. | |
4441 | * The same thing could be achieved by doing this step | |
4442 | * afterwards, and pretending it was a local activate. | |
4443 | * This way is cleaner and logically correct. | |
4444 | */ | |
4445 | p->timestamp = p->timestamp - rq_src->timestamp_last_tick | |
4446 | + rq_dest->timestamp_last_tick; | |
4447 | deactivate_task(p, rq_src); | |
4448 | activate_task(p, rq_dest, 0); | |
4449 | if (TASK_PREEMPTS_CURR(p, rq_dest)) | |
4450 | resched_task(rq_dest->curr); | |
4451 | } | |
efc30814 | 4452 | ret = 1; |
1da177e4 LT |
4453 | out: |
4454 | double_rq_unlock(rq_src, rq_dest); | |
efc30814 | 4455 | return ret; |
1da177e4 LT |
4456 | } |
4457 | ||
4458 | /* | |
4459 | * migration_thread - this is a highprio system thread that performs | |
4460 | * thread migration by bumping thread off CPU then 'pushing' onto | |
4461 | * another runqueue. | |
4462 | */ | |
95cdf3b7 | 4463 | static int migration_thread(void *data) |
1da177e4 LT |
4464 | { |
4465 | runqueue_t *rq; | |
4466 | int cpu = (long)data; | |
4467 | ||
4468 | rq = cpu_rq(cpu); | |
4469 | BUG_ON(rq->migration_thread != current); | |
4470 | ||
4471 | set_current_state(TASK_INTERRUPTIBLE); | |
4472 | while (!kthread_should_stop()) { | |
4473 | struct list_head *head; | |
4474 | migration_req_t *req; | |
4475 | ||
3e1d1d28 | 4476 | try_to_freeze(); |
1da177e4 LT |
4477 | |
4478 | spin_lock_irq(&rq->lock); | |
4479 | ||
4480 | if (cpu_is_offline(cpu)) { | |
4481 | spin_unlock_irq(&rq->lock); | |
4482 | goto wait_to_die; | |
4483 | } | |
4484 | ||
4485 | if (rq->active_balance) { | |
4486 | active_load_balance(rq, cpu); | |
4487 | rq->active_balance = 0; | |
4488 | } | |
4489 | ||
4490 | head = &rq->migration_queue; | |
4491 | ||
4492 | if (list_empty(head)) { | |
4493 | spin_unlock_irq(&rq->lock); | |
4494 | schedule(); | |
4495 | set_current_state(TASK_INTERRUPTIBLE); | |
4496 | continue; | |
4497 | } | |
4498 | req = list_entry(head->next, migration_req_t, list); | |
4499 | list_del_init(head->next); | |
4500 | ||
674311d5 NP |
4501 | spin_unlock(&rq->lock); |
4502 | __migrate_task(req->task, cpu, req->dest_cpu); | |
4503 | local_irq_enable(); | |
1da177e4 LT |
4504 | |
4505 | complete(&req->done); | |
4506 | } | |
4507 | __set_current_state(TASK_RUNNING); | |
4508 | return 0; | |
4509 | ||
4510 | wait_to_die: | |
4511 | /* Wait for kthread_stop */ | |
4512 | set_current_state(TASK_INTERRUPTIBLE); | |
4513 | while (!kthread_should_stop()) { | |
4514 | schedule(); | |
4515 | set_current_state(TASK_INTERRUPTIBLE); | |
4516 | } | |
4517 | __set_current_state(TASK_RUNNING); | |
4518 | return 0; | |
4519 | } | |
4520 | ||
4521 | #ifdef CONFIG_HOTPLUG_CPU | |
4522 | /* Figure out where task on dead CPU should go, use force if neccessary. */ | |
4523 | static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *tsk) | |
4524 | { | |
efc30814 KK |
4525 | runqueue_t *rq; |
4526 | unsigned long flags; | |
1da177e4 LT |
4527 | int dest_cpu; |
4528 | cpumask_t mask; | |
4529 | ||
efc30814 | 4530 | restart: |
1da177e4 LT |
4531 | /* On same node? */ |
4532 | mask = node_to_cpumask(cpu_to_node(dead_cpu)); | |
4533 | cpus_and(mask, mask, tsk->cpus_allowed); | |
4534 | dest_cpu = any_online_cpu(mask); | |
4535 | ||
4536 | /* On any allowed CPU? */ | |
4537 | if (dest_cpu == NR_CPUS) | |
4538 | dest_cpu = any_online_cpu(tsk->cpus_allowed); | |
4539 | ||
4540 | /* No more Mr. Nice Guy. */ | |
4541 | if (dest_cpu == NR_CPUS) { | |
efc30814 | 4542 | rq = task_rq_lock(tsk, &flags); |
b39c4fab | 4543 | cpus_setall(tsk->cpus_allowed); |
1da177e4 | 4544 | dest_cpu = any_online_cpu(tsk->cpus_allowed); |
efc30814 | 4545 | task_rq_unlock(rq, &flags); |
1da177e4 LT |
4546 | |
4547 | /* | |
4548 | * Don't tell them about moving exiting tasks or | |
4549 | * kernel threads (both mm NULL), since they never | |
4550 | * leave kernel. | |
4551 | */ | |
4552 | if (tsk->mm && printk_ratelimit()) | |
4553 | printk(KERN_INFO "process %d (%s) no " | |
4554 | "longer affine to cpu%d\n", | |
4555 | tsk->pid, tsk->comm, dead_cpu); | |
4556 | } | |
efc30814 KK |
4557 | if (!__migrate_task(tsk, dead_cpu, dest_cpu)) |
4558 | goto restart; | |
1da177e4 LT |
4559 | } |
4560 | ||
4561 | /* | |
4562 | * While a dead CPU has no uninterruptible tasks queued at this point, | |
4563 | * it might still have a nonzero ->nr_uninterruptible counter, because | |
4564 | * for performance reasons the counter is not stricly tracking tasks to | |
4565 | * their home CPUs. So we just add the counter to another CPU's counter, | |
4566 | * to keep the global sum constant after CPU-down: | |
4567 | */ | |
4568 | static void migrate_nr_uninterruptible(runqueue_t *rq_src) | |
4569 | { | |
4570 | runqueue_t *rq_dest = cpu_rq(any_online_cpu(CPU_MASK_ALL)); | |
4571 | unsigned long flags; | |
4572 | ||
4573 | local_irq_save(flags); | |
4574 | double_rq_lock(rq_src, rq_dest); | |
4575 | rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; | |
4576 | rq_src->nr_uninterruptible = 0; | |
4577 | double_rq_unlock(rq_src, rq_dest); | |
4578 | local_irq_restore(flags); | |
4579 | } | |
4580 | ||
4581 | /* Run through task list and migrate tasks from the dead cpu. */ | |
4582 | static void migrate_live_tasks(int src_cpu) | |
4583 | { | |
4584 | struct task_struct *tsk, *t; | |
4585 | ||
4586 | write_lock_irq(&tasklist_lock); | |
4587 | ||
4588 | do_each_thread(t, tsk) { | |
4589 | if (tsk == current) | |
4590 | continue; | |
4591 | ||
4592 | if (task_cpu(tsk) == src_cpu) | |
4593 | move_task_off_dead_cpu(src_cpu, tsk); | |
4594 | } while_each_thread(t, tsk); | |
4595 | ||
4596 | write_unlock_irq(&tasklist_lock); | |
4597 | } | |
4598 | ||
4599 | /* Schedules idle task to be the next runnable task on current CPU. | |
4600 | * It does so by boosting its priority to highest possible and adding it to | |
4601 | * the _front_ of runqueue. Used by CPU offline code. | |
4602 | */ | |
4603 | void sched_idle_next(void) | |
4604 | { | |
4605 | int cpu = smp_processor_id(); | |
4606 | runqueue_t *rq = this_rq(); | |
4607 | struct task_struct *p = rq->idle; | |
4608 | unsigned long flags; | |
4609 | ||
4610 | /* cpu has to be offline */ | |
4611 | BUG_ON(cpu_online(cpu)); | |
4612 | ||
4613 | /* Strictly not necessary since rest of the CPUs are stopped by now | |
4614 | * and interrupts disabled on current cpu. | |
4615 | */ | |
4616 | spin_lock_irqsave(&rq->lock, flags); | |
4617 | ||
4618 | __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); | |
4619 | /* Add idle task to _front_ of it's priority queue */ | |
4620 | __activate_idle_task(p, rq); | |
4621 | ||
4622 | spin_unlock_irqrestore(&rq->lock, flags); | |
4623 | } | |
4624 | ||
4625 | /* Ensures that the idle task is using init_mm right before its cpu goes | |
4626 | * offline. | |
4627 | */ | |
4628 | void idle_task_exit(void) | |
4629 | { | |
4630 | struct mm_struct *mm = current->active_mm; | |
4631 | ||
4632 | BUG_ON(cpu_online(smp_processor_id())); | |
4633 | ||
4634 | if (mm != &init_mm) | |
4635 | switch_mm(mm, &init_mm, current); | |
4636 | mmdrop(mm); | |
4637 | } | |
4638 | ||
4639 | static void migrate_dead(unsigned int dead_cpu, task_t *tsk) | |
4640 | { | |
4641 | struct runqueue *rq = cpu_rq(dead_cpu); | |
4642 | ||
4643 | /* Must be exiting, otherwise would be on tasklist. */ | |
4644 | BUG_ON(tsk->exit_state != EXIT_ZOMBIE && tsk->exit_state != EXIT_DEAD); | |
4645 | ||
4646 | /* Cannot have done final schedule yet: would have vanished. */ | |
4647 | BUG_ON(tsk->flags & PF_DEAD); | |
4648 | ||
4649 | get_task_struct(tsk); | |
4650 | ||
4651 | /* | |
4652 | * Drop lock around migration; if someone else moves it, | |
4653 | * that's OK. No task can be added to this CPU, so iteration is | |
4654 | * fine. | |
4655 | */ | |
4656 | spin_unlock_irq(&rq->lock); | |
4657 | move_task_off_dead_cpu(dead_cpu, tsk); | |
4658 | spin_lock_irq(&rq->lock); | |
4659 | ||
4660 | put_task_struct(tsk); | |
4661 | } | |
4662 | ||
4663 | /* release_task() removes task from tasklist, so we won't find dead tasks. */ | |
4664 | static void migrate_dead_tasks(unsigned int dead_cpu) | |
4665 | { | |
4666 | unsigned arr, i; | |
4667 | struct runqueue *rq = cpu_rq(dead_cpu); | |
4668 | ||
4669 | for (arr = 0; arr < 2; arr++) { | |
4670 | for (i = 0; i < MAX_PRIO; i++) { | |
4671 | struct list_head *list = &rq->arrays[arr].queue[i]; | |
4672 | while (!list_empty(list)) | |
4673 | migrate_dead(dead_cpu, | |
4674 | list_entry(list->next, task_t, | |
4675 | run_list)); | |
4676 | } | |
4677 | } | |
4678 | } | |
4679 | #endif /* CONFIG_HOTPLUG_CPU */ | |
4680 | ||
4681 | /* | |
4682 | * migration_call - callback that gets triggered when a CPU is added. | |
4683 | * Here we can start up the necessary migration thread for the new CPU. | |
4684 | */ | |
26c2143b CS |
4685 | static int __cpuinit migration_call(struct notifier_block *nfb, |
4686 | unsigned long action, | |
4687 | void *hcpu) | |
1da177e4 LT |
4688 | { |
4689 | int cpu = (long)hcpu; | |
4690 | struct task_struct *p; | |
4691 | struct runqueue *rq; | |
4692 | unsigned long flags; | |
4693 | ||
4694 | switch (action) { | |
4695 | case CPU_UP_PREPARE: | |
4696 | p = kthread_create(migration_thread, hcpu, "migration/%d",cpu); | |
4697 | if (IS_ERR(p)) | |
4698 | return NOTIFY_BAD; | |
4699 | p->flags |= PF_NOFREEZE; | |
4700 | kthread_bind(p, cpu); | |
4701 | /* Must be high prio: stop_machine expects to yield to it. */ | |
4702 | rq = task_rq_lock(p, &flags); | |
4703 | __setscheduler(p, SCHED_FIFO, MAX_RT_PRIO-1); | |
4704 | task_rq_unlock(rq, &flags); | |
4705 | cpu_rq(cpu)->migration_thread = p; | |
4706 | break; | |
4707 | case CPU_ONLINE: | |
4708 | /* Strictly unneccessary, as first user will wake it. */ | |
4709 | wake_up_process(cpu_rq(cpu)->migration_thread); | |
4710 | break; | |
4711 | #ifdef CONFIG_HOTPLUG_CPU | |
4712 | case CPU_UP_CANCELED: | |
fc75cdfa HC |
4713 | if (!cpu_rq(cpu)->migration_thread) |
4714 | break; | |
1da177e4 | 4715 | /* Unbind it from offline cpu so it can run. Fall thru. */ |
a4c4af7c HC |
4716 | kthread_bind(cpu_rq(cpu)->migration_thread, |
4717 | any_online_cpu(cpu_online_map)); | |
1da177e4 LT |
4718 | kthread_stop(cpu_rq(cpu)->migration_thread); |
4719 | cpu_rq(cpu)->migration_thread = NULL; | |
4720 | break; | |
4721 | case CPU_DEAD: | |
4722 | migrate_live_tasks(cpu); | |
4723 | rq = cpu_rq(cpu); | |
4724 | kthread_stop(rq->migration_thread); | |
4725 | rq->migration_thread = NULL; | |
4726 | /* Idle task back to normal (off runqueue, low prio) */ | |
4727 | rq = task_rq_lock(rq->idle, &flags); | |
4728 | deactivate_task(rq->idle, rq); | |
4729 | rq->idle->static_prio = MAX_PRIO; | |
4730 | __setscheduler(rq->idle, SCHED_NORMAL, 0); | |
4731 | migrate_dead_tasks(cpu); | |
4732 | task_rq_unlock(rq, &flags); | |
4733 | migrate_nr_uninterruptible(rq); | |
4734 | BUG_ON(rq->nr_running != 0); | |
4735 | ||
4736 | /* No need to migrate the tasks: it was best-effort if | |
4737 | * they didn't do lock_cpu_hotplug(). Just wake up | |
4738 | * the requestors. */ | |
4739 | spin_lock_irq(&rq->lock); | |
4740 | while (!list_empty(&rq->migration_queue)) { | |
4741 | migration_req_t *req; | |
4742 | req = list_entry(rq->migration_queue.next, | |
4743 | migration_req_t, list); | |
1da177e4 LT |
4744 | list_del_init(&req->list); |
4745 | complete(&req->done); | |
4746 | } | |
4747 | spin_unlock_irq(&rq->lock); | |
4748 | break; | |
4749 | #endif | |
4750 | } | |
4751 | return NOTIFY_OK; | |
4752 | } | |
4753 | ||
4754 | /* Register at highest priority so that task migration (migrate_all_tasks) | |
4755 | * happens before everything else. | |
4756 | */ | |
26c2143b | 4757 | static struct notifier_block __cpuinitdata migration_notifier = { |
1da177e4 LT |
4758 | .notifier_call = migration_call, |
4759 | .priority = 10 | |
4760 | }; | |
4761 | ||
4762 | int __init migration_init(void) | |
4763 | { | |
4764 | void *cpu = (void *)(long)smp_processor_id(); | |
4765 | /* Start one for boot CPU. */ | |
4766 | migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); | |
4767 | migration_call(&migration_notifier, CPU_ONLINE, cpu); | |
4768 | register_cpu_notifier(&migration_notifier); | |
4769 | return 0; | |
4770 | } | |
4771 | #endif | |
4772 | ||
4773 | #ifdef CONFIG_SMP | |
1a20ff27 | 4774 | #undef SCHED_DOMAIN_DEBUG |
1da177e4 LT |
4775 | #ifdef SCHED_DOMAIN_DEBUG |
4776 | static void sched_domain_debug(struct sched_domain *sd, int cpu) | |
4777 | { | |
4778 | int level = 0; | |
4779 | ||
41c7ce9a NP |
4780 | if (!sd) { |
4781 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
4782 | return; | |
4783 | } | |
4784 | ||
1da177e4 LT |
4785 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
4786 | ||
4787 | do { | |
4788 | int i; | |
4789 | char str[NR_CPUS]; | |
4790 | struct sched_group *group = sd->groups; | |
4791 | cpumask_t groupmask; | |
4792 | ||
4793 | cpumask_scnprintf(str, NR_CPUS, sd->span); | |
4794 | cpus_clear(groupmask); | |
4795 | ||
4796 | printk(KERN_DEBUG); | |
4797 | for (i = 0; i < level + 1; i++) | |
4798 | printk(" "); | |
4799 | printk("domain %d: ", level); | |
4800 | ||
4801 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
4802 | printk("does not load-balance\n"); | |
4803 | if (sd->parent) | |
4804 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain has parent"); | |
4805 | break; | |
4806 | } | |
4807 | ||
4808 | printk("span %s\n", str); | |
4809 | ||
4810 | if (!cpu_isset(cpu, sd->span)) | |
4811 | printk(KERN_ERR "ERROR: domain->span does not contain CPU%d\n", cpu); | |
4812 | if (!cpu_isset(cpu, group->cpumask)) | |
4813 | printk(KERN_ERR "ERROR: domain->groups does not contain CPU%d\n", cpu); | |
4814 | ||
4815 | printk(KERN_DEBUG); | |
4816 | for (i = 0; i < level + 2; i++) | |
4817 | printk(" "); | |
4818 | printk("groups:"); | |
4819 | do { | |
4820 | if (!group) { | |
4821 | printk("\n"); | |
4822 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
4823 | break; | |
4824 | } | |
4825 | ||
4826 | if (!group->cpu_power) { | |
4827 | printk("\n"); | |
4828 | printk(KERN_ERR "ERROR: domain->cpu_power not set\n"); | |
4829 | } | |
4830 | ||
4831 | if (!cpus_weight(group->cpumask)) { | |
4832 | printk("\n"); | |
4833 | printk(KERN_ERR "ERROR: empty group\n"); | |
4834 | } | |
4835 | ||
4836 | if (cpus_intersects(groupmask, group->cpumask)) { | |
4837 | printk("\n"); | |
4838 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
4839 | } | |
4840 | ||
4841 | cpus_or(groupmask, groupmask, group->cpumask); | |
4842 | ||
4843 | cpumask_scnprintf(str, NR_CPUS, group->cpumask); | |
4844 | printk(" %s", str); | |
4845 | ||
4846 | group = group->next; | |
4847 | } while (group != sd->groups); | |
4848 | printk("\n"); | |
4849 | ||
4850 | if (!cpus_equal(sd->span, groupmask)) | |
4851 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); | |
4852 | ||
4853 | level++; | |
4854 | sd = sd->parent; | |
4855 | ||
4856 | if (sd) { | |
4857 | if (!cpus_subset(groupmask, sd->span)) | |
4858 | printk(KERN_ERR "ERROR: parent span is not a superset of domain->span\n"); | |
4859 | } | |
4860 | ||
4861 | } while (sd); | |
4862 | } | |
4863 | #else | |
4864 | #define sched_domain_debug(sd, cpu) {} | |
4865 | #endif | |
4866 | ||
1a20ff27 | 4867 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 SS |
4868 | { |
4869 | if (cpus_weight(sd->span) == 1) | |
4870 | return 1; | |
4871 | ||
4872 | /* Following flags need at least 2 groups */ | |
4873 | if (sd->flags & (SD_LOAD_BALANCE | | |
4874 | SD_BALANCE_NEWIDLE | | |
4875 | SD_BALANCE_FORK | | |
4876 | SD_BALANCE_EXEC)) { | |
4877 | if (sd->groups != sd->groups->next) | |
4878 | return 0; | |
4879 | } | |
4880 | ||
4881 | /* Following flags don't use groups */ | |
4882 | if (sd->flags & (SD_WAKE_IDLE | | |
4883 | SD_WAKE_AFFINE | | |
4884 | SD_WAKE_BALANCE)) | |
4885 | return 0; | |
4886 | ||
4887 | return 1; | |
4888 | } | |
4889 | ||
1a20ff27 | 4890 | static int sd_parent_degenerate(struct sched_domain *sd, |
245af2c7 SS |
4891 | struct sched_domain *parent) |
4892 | { | |
4893 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
4894 | ||
4895 | if (sd_degenerate(parent)) | |
4896 | return 1; | |
4897 | ||
4898 | if (!cpus_equal(sd->span, parent->span)) | |
4899 | return 0; | |
4900 | ||
4901 | /* Does parent contain flags not in child? */ | |
4902 | /* WAKE_BALANCE is a subset of WAKE_AFFINE */ | |
4903 | if (cflags & SD_WAKE_AFFINE) | |
4904 | pflags &= ~SD_WAKE_BALANCE; | |
4905 | /* Flags needing groups don't count if only 1 group in parent */ | |
4906 | if (parent->groups == parent->groups->next) { | |
4907 | pflags &= ~(SD_LOAD_BALANCE | | |
4908 | SD_BALANCE_NEWIDLE | | |
4909 | SD_BALANCE_FORK | | |
4910 | SD_BALANCE_EXEC); | |
4911 | } | |
4912 | if (~cflags & pflags) | |
4913 | return 0; | |
4914 | ||
4915 | return 1; | |
4916 | } | |
4917 | ||
1da177e4 LT |
4918 | /* |
4919 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must | |
4920 | * hold the hotplug lock. | |
4921 | */ | |
9c1cfda2 | 4922 | static void cpu_attach_domain(struct sched_domain *sd, int cpu) |
1da177e4 | 4923 | { |
1da177e4 | 4924 | runqueue_t *rq = cpu_rq(cpu); |
245af2c7 SS |
4925 | struct sched_domain *tmp; |
4926 | ||
4927 | /* Remove the sched domains which do not contribute to scheduling. */ | |
4928 | for (tmp = sd; tmp; tmp = tmp->parent) { | |
4929 | struct sched_domain *parent = tmp->parent; | |
4930 | if (!parent) | |
4931 | break; | |
4932 | if (sd_parent_degenerate(tmp, parent)) | |
4933 | tmp->parent = parent->parent; | |
4934 | } | |
4935 | ||
4936 | if (sd && sd_degenerate(sd)) | |
4937 | sd = sd->parent; | |
1da177e4 LT |
4938 | |
4939 | sched_domain_debug(sd, cpu); | |
4940 | ||
674311d5 | 4941 | rcu_assign_pointer(rq->sd, sd); |
1da177e4 LT |
4942 | } |
4943 | ||
4944 | /* cpus with isolated domains */ | |
9c1cfda2 | 4945 | static cpumask_t __devinitdata cpu_isolated_map = CPU_MASK_NONE; |
1da177e4 LT |
4946 | |
4947 | /* Setup the mask of cpus configured for isolated domains */ | |
4948 | static int __init isolated_cpu_setup(char *str) | |
4949 | { | |
4950 | int ints[NR_CPUS], i; | |
4951 | ||
4952 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
4953 | cpus_clear(cpu_isolated_map); | |
4954 | for (i = 1; i <= ints[0]; i++) | |
4955 | if (ints[i] < NR_CPUS) | |
4956 | cpu_set(ints[i], cpu_isolated_map); | |
4957 | return 1; | |
4958 | } | |
4959 | ||
4960 | __setup ("isolcpus=", isolated_cpu_setup); | |
4961 | ||
4962 | /* | |
4963 | * init_sched_build_groups takes an array of groups, the cpumask we wish | |
4964 | * to span, and a pointer to a function which identifies what group a CPU | |
4965 | * belongs to. The return value of group_fn must be a valid index into the | |
4966 | * groups[] array, and must be >= 0 and < NR_CPUS (due to the fact that we | |
4967 | * keep track of groups covered with a cpumask_t). | |
4968 | * | |
4969 | * init_sched_build_groups will build a circular linked list of the groups | |
4970 | * covered by the given span, and will set each group's ->cpumask correctly, | |
4971 | * and ->cpu_power to 0. | |
4972 | */ | |
9c1cfda2 JH |
4973 | static void init_sched_build_groups(struct sched_group groups[], cpumask_t span, |
4974 | int (*group_fn)(int cpu)) | |
1da177e4 LT |
4975 | { |
4976 | struct sched_group *first = NULL, *last = NULL; | |
4977 | cpumask_t covered = CPU_MASK_NONE; | |
4978 | int i; | |
4979 | ||
4980 | for_each_cpu_mask(i, span) { | |
4981 | int group = group_fn(i); | |
4982 | struct sched_group *sg = &groups[group]; | |
4983 | int j; | |
4984 | ||
4985 | if (cpu_isset(i, covered)) | |
4986 | continue; | |
4987 | ||
4988 | sg->cpumask = CPU_MASK_NONE; | |
4989 | sg->cpu_power = 0; | |
4990 | ||
4991 | for_each_cpu_mask(j, span) { | |
4992 | if (group_fn(j) != group) | |
4993 | continue; | |
4994 | ||
4995 | cpu_set(j, covered); | |
4996 | cpu_set(j, sg->cpumask); | |
4997 | } | |
4998 | if (!first) | |
4999 | first = sg; | |
5000 | if (last) | |
5001 | last->next = sg; | |
5002 | last = sg; | |
5003 | } | |
5004 | last->next = first; | |
5005 | } | |
5006 | ||
9c1cfda2 | 5007 | #define SD_NODES_PER_DOMAIN 16 |
1da177e4 | 5008 | |
198e2f18 | 5009 | /* |
5010 | * Self-tuning task migration cost measurement between source and target CPUs. | |
5011 | * | |
5012 | * This is done by measuring the cost of manipulating buffers of varying | |
5013 | * sizes. For a given buffer-size here are the steps that are taken: | |
5014 | * | |
5015 | * 1) the source CPU reads+dirties a shared buffer | |
5016 | * 2) the target CPU reads+dirties the same shared buffer | |
5017 | * | |
5018 | * We measure how long they take, in the following 4 scenarios: | |
5019 | * | |
5020 | * - source: CPU1, target: CPU2 | cost1 | |
5021 | * - source: CPU2, target: CPU1 | cost2 | |
5022 | * - source: CPU1, target: CPU1 | cost3 | |
5023 | * - source: CPU2, target: CPU2 | cost4 | |
5024 | * | |
5025 | * We then calculate the cost3+cost4-cost1-cost2 difference - this is | |
5026 | * the cost of migration. | |
5027 | * | |
5028 | * We then start off from a small buffer-size and iterate up to larger | |
5029 | * buffer sizes, in 5% steps - measuring each buffer-size separately, and | |
5030 | * doing a maximum search for the cost. (The maximum cost for a migration | |
5031 | * normally occurs when the working set size is around the effective cache | |
5032 | * size.) | |
5033 | */ | |
5034 | #define SEARCH_SCOPE 2 | |
5035 | #define MIN_CACHE_SIZE (64*1024U) | |
5036 | #define DEFAULT_CACHE_SIZE (5*1024*1024U) | |
70b4d63e | 5037 | #define ITERATIONS 1 |
198e2f18 | 5038 | #define SIZE_THRESH 130 |
5039 | #define COST_THRESH 130 | |
5040 | ||
5041 | /* | |
5042 | * The migration cost is a function of 'domain distance'. Domain | |
5043 | * distance is the number of steps a CPU has to iterate down its | |
5044 | * domain tree to share a domain with the other CPU. The farther | |
5045 | * two CPUs are from each other, the larger the distance gets. | |
5046 | * | |
5047 | * Note that we use the distance only to cache measurement results, | |
5048 | * the distance value is not used numerically otherwise. When two | |
5049 | * CPUs have the same distance it is assumed that the migration | |
5050 | * cost is the same. (this is a simplification but quite practical) | |
5051 | */ | |
5052 | #define MAX_DOMAIN_DISTANCE 32 | |
5053 | ||
5054 | static unsigned long long migration_cost[MAX_DOMAIN_DISTANCE] = | |
4bbf39c2 IM |
5055 | { [ 0 ... MAX_DOMAIN_DISTANCE-1 ] = |
5056 | /* | |
5057 | * Architectures may override the migration cost and thus avoid | |
5058 | * boot-time calibration. Unit is nanoseconds. Mostly useful for | |
5059 | * virtualized hardware: | |
5060 | */ | |
5061 | #ifdef CONFIG_DEFAULT_MIGRATION_COST | |
5062 | CONFIG_DEFAULT_MIGRATION_COST | |
5063 | #else | |
5064 | -1LL | |
5065 | #endif | |
5066 | }; | |
198e2f18 | 5067 | |
5068 | /* | |
5069 | * Allow override of migration cost - in units of microseconds. | |
5070 | * E.g. migration_cost=1000,2000,3000 will set up a level-1 cost | |
5071 | * of 1 msec, level-2 cost of 2 msecs and level3 cost of 3 msecs: | |
5072 | */ | |
5073 | static int __init migration_cost_setup(char *str) | |
5074 | { | |
5075 | int ints[MAX_DOMAIN_DISTANCE+1], i; | |
5076 | ||
5077 | str = get_options(str, ARRAY_SIZE(ints), ints); | |
5078 | ||
5079 | printk("#ints: %d\n", ints[0]); | |
5080 | for (i = 1; i <= ints[0]; i++) { | |
5081 | migration_cost[i-1] = (unsigned long long)ints[i]*1000; | |
5082 | printk("migration_cost[%d]: %Ld\n", i-1, migration_cost[i-1]); | |
5083 | } | |
5084 | return 1; | |
5085 | } | |
5086 | ||
5087 | __setup ("migration_cost=", migration_cost_setup); | |
5088 | ||
5089 | /* | |
5090 | * Global multiplier (divisor) for migration-cutoff values, | |
5091 | * in percentiles. E.g. use a value of 150 to get 1.5 times | |
5092 | * longer cache-hot cutoff times. | |
5093 | * | |
5094 | * (We scale it from 100 to 128 to long long handling easier.) | |
5095 | */ | |
5096 | ||
5097 | #define MIGRATION_FACTOR_SCALE 128 | |
5098 | ||
5099 | static unsigned int migration_factor = MIGRATION_FACTOR_SCALE; | |
5100 | ||
5101 | static int __init setup_migration_factor(char *str) | |
5102 | { | |
5103 | get_option(&str, &migration_factor); | |
5104 | migration_factor = migration_factor * MIGRATION_FACTOR_SCALE / 100; | |
5105 | return 1; | |
5106 | } | |
5107 | ||
5108 | __setup("migration_factor=", setup_migration_factor); | |
5109 | ||
5110 | /* | |
5111 | * Estimated distance of two CPUs, measured via the number of domains | |
5112 | * we have to pass for the two CPUs to be in the same span: | |
5113 | */ | |
5114 | static unsigned long domain_distance(int cpu1, int cpu2) | |
5115 | { | |
5116 | unsigned long distance = 0; | |
5117 | struct sched_domain *sd; | |
5118 | ||
5119 | for_each_domain(cpu1, sd) { | |
5120 | WARN_ON(!cpu_isset(cpu1, sd->span)); | |
5121 | if (cpu_isset(cpu2, sd->span)) | |
5122 | return distance; | |
5123 | distance++; | |
5124 | } | |
5125 | if (distance >= MAX_DOMAIN_DISTANCE) { | |
5126 | WARN_ON(1); | |
5127 | distance = MAX_DOMAIN_DISTANCE-1; | |
5128 | } | |
5129 | ||
5130 | return distance; | |
5131 | } | |
5132 | ||
5133 | static unsigned int migration_debug; | |
5134 | ||
5135 | static int __init setup_migration_debug(char *str) | |
5136 | { | |
5137 | get_option(&str, &migration_debug); | |
5138 | return 1; | |
5139 | } | |
5140 | ||
5141 | __setup("migration_debug=", setup_migration_debug); | |
5142 | ||
5143 | /* | |
5144 | * Maximum cache-size that the scheduler should try to measure. | |
5145 | * Architectures with larger caches should tune this up during | |
5146 | * bootup. Gets used in the domain-setup code (i.e. during SMP | |
5147 | * bootup). | |
5148 | */ | |
5149 | unsigned int max_cache_size; | |
5150 | ||
5151 | static int __init setup_max_cache_size(char *str) | |
5152 | { | |
5153 | get_option(&str, &max_cache_size); | |
5154 | return 1; | |
5155 | } | |
5156 | ||
5157 | __setup("max_cache_size=", setup_max_cache_size); | |
5158 | ||
5159 | /* | |
5160 | * Dirty a big buffer in a hard-to-predict (for the L2 cache) way. This | |
5161 | * is the operation that is timed, so we try to generate unpredictable | |
5162 | * cachemisses that still end up filling the L2 cache: | |
5163 | */ | |
5164 | static void touch_cache(void *__cache, unsigned long __size) | |
5165 | { | |
5166 | unsigned long size = __size/sizeof(long), chunk1 = size/3, | |
5167 | chunk2 = 2*size/3; | |
5168 | unsigned long *cache = __cache; | |
5169 | int i; | |
5170 | ||
5171 | for (i = 0; i < size/6; i += 8) { | |
5172 | switch (i % 6) { | |
5173 | case 0: cache[i]++; | |
5174 | case 1: cache[size-1-i]++; | |
5175 | case 2: cache[chunk1-i]++; | |
5176 | case 3: cache[chunk1+i]++; | |
5177 | case 4: cache[chunk2-i]++; | |
5178 | case 5: cache[chunk2+i]++; | |
5179 | } | |
5180 | } | |
5181 | } | |
5182 | ||
5183 | /* | |
5184 | * Measure the cache-cost of one task migration. Returns in units of nsec. | |
5185 | */ | |
5186 | static unsigned long long measure_one(void *cache, unsigned long size, | |
5187 | int source, int target) | |
5188 | { | |
5189 | cpumask_t mask, saved_mask; | |
5190 | unsigned long long t0, t1, t2, t3, cost; | |
5191 | ||
5192 | saved_mask = current->cpus_allowed; | |
5193 | ||
5194 | /* | |
5195 | * Flush source caches to RAM and invalidate them: | |
5196 | */ | |
5197 | sched_cacheflush(); | |
5198 | ||
5199 | /* | |
5200 | * Migrate to the source CPU: | |
5201 | */ | |
5202 | mask = cpumask_of_cpu(source); | |
5203 | set_cpus_allowed(current, mask); | |
5204 | WARN_ON(smp_processor_id() != source); | |
5205 | ||
5206 | /* | |
5207 | * Dirty the working set: | |
5208 | */ | |
5209 | t0 = sched_clock(); | |
5210 | touch_cache(cache, size); | |
5211 | t1 = sched_clock(); | |
5212 | ||
5213 | /* | |
5214 | * Migrate to the target CPU, dirty the L2 cache and access | |
5215 | * the shared buffer. (which represents the working set | |
5216 | * of a migrated task.) | |
5217 | */ | |
5218 | mask = cpumask_of_cpu(target); | |
5219 | set_cpus_allowed(current, mask); | |
5220 | WARN_ON(smp_processor_id() != target); | |
5221 | ||
5222 | t2 = sched_clock(); | |
5223 | touch_cache(cache, size); | |
5224 | t3 = sched_clock(); | |
5225 | ||
5226 | cost = t1-t0 + t3-t2; | |
5227 | ||
5228 | if (migration_debug >= 2) | |
5229 | printk("[%d->%d]: %8Ld %8Ld %8Ld => %10Ld.\n", | |
5230 | source, target, t1-t0, t1-t0, t3-t2, cost); | |
5231 | /* | |
5232 | * Flush target caches to RAM and invalidate them: | |
5233 | */ | |
5234 | sched_cacheflush(); | |
5235 | ||
5236 | set_cpus_allowed(current, saved_mask); | |
5237 | ||
5238 | return cost; | |
5239 | } | |
5240 | ||
5241 | /* | |
5242 | * Measure a series of task migrations and return the average | |
5243 | * result. Since this code runs early during bootup the system | |
5244 | * is 'undisturbed' and the average latency makes sense. | |
5245 | * | |
5246 | * The algorithm in essence auto-detects the relevant cache-size, | |
5247 | * so it will properly detect different cachesizes for different | |
5248 | * cache-hierarchies, depending on how the CPUs are connected. | |
5249 | * | |
5250 | * Architectures can prime the upper limit of the search range via | |
5251 | * max_cache_size, otherwise the search range defaults to 20MB...64K. | |
5252 | */ | |
5253 | static unsigned long long | |
5254 | measure_cost(int cpu1, int cpu2, void *cache, unsigned int size) | |
5255 | { | |
5256 | unsigned long long cost1, cost2; | |
5257 | int i; | |
5258 | ||
5259 | /* | |
5260 | * Measure the migration cost of 'size' bytes, over an | |
5261 | * average of 10 runs: | |
5262 | * | |
5263 | * (We perturb the cache size by a small (0..4k) | |
5264 | * value to compensate size/alignment related artifacts. | |
5265 | * We also subtract the cost of the operation done on | |
5266 | * the same CPU.) | |
5267 | */ | |
5268 | cost1 = 0; | |
5269 | ||
5270 | /* | |
5271 | * dry run, to make sure we start off cache-cold on cpu1, | |
5272 | * and to get any vmalloc pagefaults in advance: | |
5273 | */ | |
5274 | measure_one(cache, size, cpu1, cpu2); | |
5275 | for (i = 0; i < ITERATIONS; i++) | |
5276 | cost1 += measure_one(cache, size - i*1024, cpu1, cpu2); | |
5277 | ||
5278 | measure_one(cache, size, cpu2, cpu1); | |
5279 | for (i = 0; i < ITERATIONS; i++) | |
5280 | cost1 += measure_one(cache, size - i*1024, cpu2, cpu1); | |
5281 | ||
5282 | /* | |
5283 | * (We measure the non-migrating [cached] cost on both | |
5284 | * cpu1 and cpu2, to handle CPUs with different speeds) | |
5285 | */ | |
5286 | cost2 = 0; | |
5287 | ||
5288 | measure_one(cache, size, cpu1, cpu1); | |
5289 | for (i = 0; i < ITERATIONS; i++) | |
5290 | cost2 += measure_one(cache, size - i*1024, cpu1, cpu1); | |
5291 | ||
5292 | measure_one(cache, size, cpu2, cpu2); | |
5293 | for (i = 0; i < ITERATIONS; i++) | |
5294 | cost2 += measure_one(cache, size - i*1024, cpu2, cpu2); | |
5295 | ||
5296 | /* | |
5297 | * Get the per-iteration migration cost: | |
5298 | */ | |
5299 | do_div(cost1, 2*ITERATIONS); | |
5300 | do_div(cost2, 2*ITERATIONS); | |
5301 | ||
5302 | return cost1 - cost2; | |
5303 | } | |
5304 | ||
5305 | static unsigned long long measure_migration_cost(int cpu1, int cpu2) | |
5306 | { | |
5307 | unsigned long long max_cost = 0, fluct = 0, avg_fluct = 0; | |
5308 | unsigned int max_size, size, size_found = 0; | |
5309 | long long cost = 0, prev_cost; | |
5310 | void *cache; | |
5311 | ||
5312 | /* | |
5313 | * Search from max_cache_size*5 down to 64K - the real relevant | |
5314 | * cachesize has to lie somewhere inbetween. | |
5315 | */ | |
5316 | if (max_cache_size) { | |
5317 | max_size = max(max_cache_size * SEARCH_SCOPE, MIN_CACHE_SIZE); | |
5318 | size = max(max_cache_size / SEARCH_SCOPE, MIN_CACHE_SIZE); | |
5319 | } else { | |
5320 | /* | |
5321 | * Since we have no estimation about the relevant | |
5322 | * search range | |
5323 | */ | |
5324 | max_size = DEFAULT_CACHE_SIZE * SEARCH_SCOPE; | |
5325 | size = MIN_CACHE_SIZE; | |
5326 | } | |
5327 | ||
5328 | if (!cpu_online(cpu1) || !cpu_online(cpu2)) { | |
5329 | printk("cpu %d and %d not both online!\n", cpu1, cpu2); | |
5330 | return 0; | |
5331 | } | |
5332 | ||
5333 | /* | |
5334 | * Allocate the working set: | |
5335 | */ | |
5336 | cache = vmalloc(max_size); | |
5337 | if (!cache) { | |
5338 | printk("could not vmalloc %d bytes for cache!\n", 2*max_size); | |
5339 | return 1000000; // return 1 msec on very small boxen | |
5340 | } | |
5341 | ||
5342 | while (size <= max_size) { | |
5343 | prev_cost = cost; | |
5344 | cost = measure_cost(cpu1, cpu2, cache, size); | |
5345 | ||
5346 | /* | |
5347 | * Update the max: | |
5348 | */ | |
5349 | if (cost > 0) { | |
5350 | if (max_cost < cost) { | |
5351 | max_cost = cost; | |
5352 | size_found = size; | |
5353 | } | |
5354 | } | |
5355 | /* | |
5356 | * Calculate average fluctuation, we use this to prevent | |
5357 | * noise from triggering an early break out of the loop: | |
5358 | */ | |
5359 | fluct = abs(cost - prev_cost); | |
5360 | avg_fluct = (avg_fluct + fluct)/2; | |
5361 | ||
5362 | if (migration_debug) | |
5363 | printk("-> [%d][%d][%7d] %3ld.%ld [%3ld.%ld] (%ld): (%8Ld %8Ld)\n", | |
5364 | cpu1, cpu2, size, | |
5365 | (long)cost / 1000000, | |
5366 | ((long)cost / 100000) % 10, | |
5367 | (long)max_cost / 1000000, | |
5368 | ((long)max_cost / 100000) % 10, | |
5369 | domain_distance(cpu1, cpu2), | |
5370 | cost, avg_fluct); | |
5371 | ||
5372 | /* | |
5373 | * If we iterated at least 20% past the previous maximum, | |
5374 | * and the cost has dropped by more than 20% already, | |
5375 | * (taking fluctuations into account) then we assume to | |
5376 | * have found the maximum and break out of the loop early: | |
5377 | */ | |
5378 | if (size_found && (size*100 > size_found*SIZE_THRESH)) | |
5379 | if (cost+avg_fluct <= 0 || | |
5380 | max_cost*100 > (cost+avg_fluct)*COST_THRESH) { | |
5381 | ||
5382 | if (migration_debug) | |
5383 | printk("-> found max.\n"); | |
5384 | break; | |
5385 | } | |
5386 | /* | |
70b4d63e | 5387 | * Increase the cachesize in 10% steps: |
198e2f18 | 5388 | */ |
70b4d63e | 5389 | size = size * 10 / 9; |
198e2f18 | 5390 | } |
5391 | ||
5392 | if (migration_debug) | |
5393 | printk("[%d][%d] working set size found: %d, cost: %Ld\n", | |
5394 | cpu1, cpu2, size_found, max_cost); | |
5395 | ||
5396 | vfree(cache); | |
5397 | ||
5398 | /* | |
5399 | * A task is considered 'cache cold' if at least 2 times | |
5400 | * the worst-case cost of migration has passed. | |
5401 | * | |
5402 | * (this limit is only listened to if the load-balancing | |
5403 | * situation is 'nice' - if there is a large imbalance we | |
5404 | * ignore it for the sake of CPU utilization and | |
5405 | * processing fairness.) | |
5406 | */ | |
5407 | return 2 * max_cost * migration_factor / MIGRATION_FACTOR_SCALE; | |
5408 | } | |
5409 | ||
5410 | static void calibrate_migration_costs(const cpumask_t *cpu_map) | |
5411 | { | |
5412 | int cpu1 = -1, cpu2 = -1, cpu, orig_cpu = raw_smp_processor_id(); | |
5413 | unsigned long j0, j1, distance, max_distance = 0; | |
5414 | struct sched_domain *sd; | |
5415 | ||
5416 | j0 = jiffies; | |
5417 | ||
5418 | /* | |
5419 | * First pass - calculate the cacheflush times: | |
5420 | */ | |
5421 | for_each_cpu_mask(cpu1, *cpu_map) { | |
5422 | for_each_cpu_mask(cpu2, *cpu_map) { | |
5423 | if (cpu1 == cpu2) | |
5424 | continue; | |
5425 | distance = domain_distance(cpu1, cpu2); | |
5426 | max_distance = max(max_distance, distance); | |
5427 | /* | |
5428 | * No result cached yet? | |
5429 | */ | |
5430 | if (migration_cost[distance] == -1LL) | |
5431 | migration_cost[distance] = | |
5432 | measure_migration_cost(cpu1, cpu2); | |
5433 | } | |
5434 | } | |
5435 | /* | |
5436 | * Second pass - update the sched domain hierarchy with | |
5437 | * the new cache-hot-time estimations: | |
5438 | */ | |
5439 | for_each_cpu_mask(cpu, *cpu_map) { | |
5440 | distance = 0; | |
5441 | for_each_domain(cpu, sd) { | |
5442 | sd->cache_hot_time = migration_cost[distance]; | |
5443 | distance++; | |
5444 | } | |
5445 | } | |
5446 | /* | |
5447 | * Print the matrix: | |
5448 | */ | |
5449 | if (migration_debug) | |
5450 | printk("migration: max_cache_size: %d, cpu: %d MHz:\n", | |
5451 | max_cache_size, | |
5452 | #ifdef CONFIG_X86 | |
5453 | cpu_khz/1000 | |
5454 | #else | |
5455 | -1 | |
5456 | #endif | |
5457 | ); | |
bd576c95 CE |
5458 | if (system_state == SYSTEM_BOOTING) { |
5459 | printk("migration_cost="); | |
5460 | for (distance = 0; distance <= max_distance; distance++) { | |
5461 | if (distance) | |
5462 | printk(","); | |
5463 | printk("%ld", (long)migration_cost[distance] / 1000); | |
5464 | } | |
5465 | printk("\n"); | |
198e2f18 | 5466 | } |
198e2f18 | 5467 | j1 = jiffies; |
5468 | if (migration_debug) | |
5469 | printk("migration: %ld seconds\n", (j1-j0)/HZ); | |
5470 | ||
5471 | /* | |
5472 | * Move back to the original CPU. NUMA-Q gets confused | |
5473 | * if we migrate to another quad during bootup. | |
5474 | */ | |
5475 | if (raw_smp_processor_id() != orig_cpu) { | |
5476 | cpumask_t mask = cpumask_of_cpu(orig_cpu), | |
5477 | saved_mask = current->cpus_allowed; | |
5478 | ||
5479 | set_cpus_allowed(current, mask); | |
5480 | set_cpus_allowed(current, saved_mask); | |
5481 | } | |
5482 | } | |
5483 | ||
9c1cfda2 | 5484 | #ifdef CONFIG_NUMA |
198e2f18 | 5485 | |
9c1cfda2 JH |
5486 | /** |
5487 | * find_next_best_node - find the next node to include in a sched_domain | |
5488 | * @node: node whose sched_domain we're building | |
5489 | * @used_nodes: nodes already in the sched_domain | |
5490 | * | |
5491 | * Find the next node to include in a given scheduling domain. Simply | |
5492 | * finds the closest node not already in the @used_nodes map. | |
5493 | * | |
5494 | * Should use nodemask_t. | |
5495 | */ | |
5496 | static int find_next_best_node(int node, unsigned long *used_nodes) | |
5497 | { | |
5498 | int i, n, val, min_val, best_node = 0; | |
5499 | ||
5500 | min_val = INT_MAX; | |
5501 | ||
5502 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5503 | /* Start at @node */ | |
5504 | n = (node + i) % MAX_NUMNODES; | |
5505 | ||
5506 | if (!nr_cpus_node(n)) | |
5507 | continue; | |
5508 | ||
5509 | /* Skip already used nodes */ | |
5510 | if (test_bit(n, used_nodes)) | |
5511 | continue; | |
5512 | ||
5513 | /* Simple min distance search */ | |
5514 | val = node_distance(node, n); | |
5515 | ||
5516 | if (val < min_val) { | |
5517 | min_val = val; | |
5518 | best_node = n; | |
5519 | } | |
5520 | } | |
5521 | ||
5522 | set_bit(best_node, used_nodes); | |
5523 | return best_node; | |
5524 | } | |
5525 | ||
5526 | /** | |
5527 | * sched_domain_node_span - get a cpumask for a node's sched_domain | |
5528 | * @node: node whose cpumask we're constructing | |
5529 | * @size: number of nodes to include in this span | |
5530 | * | |
5531 | * Given a node, construct a good cpumask for its sched_domain to span. It | |
5532 | * should be one that prevents unnecessary balancing, but also spreads tasks | |
5533 | * out optimally. | |
5534 | */ | |
5535 | static cpumask_t sched_domain_node_span(int node) | |
5536 | { | |
5537 | int i; | |
5538 | cpumask_t span, nodemask; | |
5539 | DECLARE_BITMAP(used_nodes, MAX_NUMNODES); | |
5540 | ||
5541 | cpus_clear(span); | |
5542 | bitmap_zero(used_nodes, MAX_NUMNODES); | |
5543 | ||
5544 | nodemask = node_to_cpumask(node); | |
5545 | cpus_or(span, span, nodemask); | |
5546 | set_bit(node, used_nodes); | |
5547 | ||
5548 | for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { | |
5549 | int next_node = find_next_best_node(node, used_nodes); | |
5550 | nodemask = node_to_cpumask(next_node); | |
5551 | cpus_or(span, span, nodemask); | |
5552 | } | |
5553 | ||
5554 | return span; | |
5555 | } | |
5556 | #endif | |
5557 | ||
5558 | /* | |
5559 | * At the moment, CONFIG_SCHED_SMT is never defined, but leave it in so we | |
5560 | * can switch it on easily if needed. | |
5561 | */ | |
1da177e4 LT |
5562 | #ifdef CONFIG_SCHED_SMT |
5563 | static DEFINE_PER_CPU(struct sched_domain, cpu_domains); | |
5564 | static struct sched_group sched_group_cpus[NR_CPUS]; | |
1a20ff27 | 5565 | static int cpu_to_cpu_group(int cpu) |
1da177e4 LT |
5566 | { |
5567 | return cpu; | |
5568 | } | |
5569 | #endif | |
5570 | ||
1e9f28fa SS |
5571 | #ifdef CONFIG_SCHED_MC |
5572 | static DEFINE_PER_CPU(struct sched_domain, core_domains); | |
5573 | static struct sched_group sched_group_core[NR_CPUS]; | |
5574 | #endif | |
5575 | ||
5576 | #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) | |
5577 | static int cpu_to_core_group(int cpu) | |
5578 | { | |
5579 | return first_cpu(cpu_sibling_map[cpu]); | |
5580 | } | |
5581 | #elif defined(CONFIG_SCHED_MC) | |
5582 | static int cpu_to_core_group(int cpu) | |
5583 | { | |
5584 | return cpu; | |
5585 | } | |
5586 | #endif | |
5587 | ||
1da177e4 LT |
5588 | static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
5589 | static struct sched_group sched_group_phys[NR_CPUS]; | |
1a20ff27 | 5590 | static int cpu_to_phys_group(int cpu) |
1da177e4 | 5591 | { |
1e9f28fa SS |
5592 | #if defined(CONFIG_SCHED_MC) |
5593 | cpumask_t mask = cpu_coregroup_map(cpu); | |
5594 | return first_cpu(mask); | |
5595 | #elif defined(CONFIG_SCHED_SMT) | |
1da177e4 LT |
5596 | return first_cpu(cpu_sibling_map[cpu]); |
5597 | #else | |
5598 | return cpu; | |
5599 | #endif | |
5600 | } | |
5601 | ||
5602 | #ifdef CONFIG_NUMA | |
1da177e4 | 5603 | /* |
9c1cfda2 JH |
5604 | * The init_sched_build_groups can't handle what we want to do with node |
5605 | * groups, so roll our own. Now each node has its own list of groups which | |
5606 | * gets dynamically allocated. | |
1da177e4 | 5607 | */ |
9c1cfda2 | 5608 | static DEFINE_PER_CPU(struct sched_domain, node_domains); |
d1b55138 | 5609 | static struct sched_group **sched_group_nodes_bycpu[NR_CPUS]; |
1da177e4 | 5610 | |
9c1cfda2 | 5611 | static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
d1b55138 | 5612 | static struct sched_group *sched_group_allnodes_bycpu[NR_CPUS]; |
9c1cfda2 JH |
5613 | |
5614 | static int cpu_to_allnodes_group(int cpu) | |
5615 | { | |
5616 | return cpu_to_node(cpu); | |
1da177e4 | 5617 | } |
08069033 SS |
5618 | static void init_numa_sched_groups_power(struct sched_group *group_head) |
5619 | { | |
5620 | struct sched_group *sg = group_head; | |
5621 | int j; | |
5622 | ||
5623 | if (!sg) | |
5624 | return; | |
5625 | next_sg: | |
5626 | for_each_cpu_mask(j, sg->cpumask) { | |
5627 | struct sched_domain *sd; | |
5628 | ||
5629 | sd = &per_cpu(phys_domains, j); | |
5630 | if (j != first_cpu(sd->groups->cpumask)) { | |
5631 | /* | |
5632 | * Only add "power" once for each | |
5633 | * physical package. | |
5634 | */ | |
5635 | continue; | |
5636 | } | |
5637 | ||
5638 | sg->cpu_power += sd->groups->cpu_power; | |
5639 | } | |
5640 | sg = sg->next; | |
5641 | if (sg != group_head) | |
5642 | goto next_sg; | |
5643 | } | |
1da177e4 LT |
5644 | #endif |
5645 | ||
5646 | /* | |
1a20ff27 DG |
5647 | * Build sched domains for a given set of cpus and attach the sched domains |
5648 | * to the individual cpus | |
1da177e4 | 5649 | */ |
9c1cfda2 | 5650 | void build_sched_domains(const cpumask_t *cpu_map) |
1da177e4 LT |
5651 | { |
5652 | int i; | |
d1b55138 JH |
5653 | #ifdef CONFIG_NUMA |
5654 | struct sched_group **sched_group_nodes = NULL; | |
5655 | struct sched_group *sched_group_allnodes = NULL; | |
5656 | ||
5657 | /* | |
5658 | * Allocate the per-node list of sched groups | |
5659 | */ | |
5660 | sched_group_nodes = kmalloc(sizeof(struct sched_group*)*MAX_NUMNODES, | |
5661 | GFP_ATOMIC); | |
5662 | if (!sched_group_nodes) { | |
5663 | printk(KERN_WARNING "Can not alloc sched group node list\n"); | |
5664 | return; | |
5665 | } | |
5666 | sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; | |
5667 | #endif | |
1da177e4 LT |
5668 | |
5669 | /* | |
1a20ff27 | 5670 | * Set up domains for cpus specified by the cpu_map. |
1da177e4 | 5671 | */ |
1a20ff27 | 5672 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5673 | int group; |
5674 | struct sched_domain *sd = NULL, *p; | |
5675 | cpumask_t nodemask = node_to_cpumask(cpu_to_node(i)); | |
5676 | ||
1a20ff27 | 5677 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5678 | |
5679 | #ifdef CONFIG_NUMA | |
d1b55138 | 5680 | if (cpus_weight(*cpu_map) |
9c1cfda2 | 5681 | > SD_NODES_PER_DOMAIN*cpus_weight(nodemask)) { |
d1b55138 JH |
5682 | if (!sched_group_allnodes) { |
5683 | sched_group_allnodes | |
5684 | = kmalloc(sizeof(struct sched_group) | |
5685 | * MAX_NUMNODES, | |
5686 | GFP_KERNEL); | |
5687 | if (!sched_group_allnodes) { | |
5688 | printk(KERN_WARNING | |
5689 | "Can not alloc allnodes sched group\n"); | |
5690 | break; | |
5691 | } | |
5692 | sched_group_allnodes_bycpu[i] | |
5693 | = sched_group_allnodes; | |
5694 | } | |
9c1cfda2 JH |
5695 | sd = &per_cpu(allnodes_domains, i); |
5696 | *sd = SD_ALLNODES_INIT; | |
5697 | sd->span = *cpu_map; | |
5698 | group = cpu_to_allnodes_group(i); | |
5699 | sd->groups = &sched_group_allnodes[group]; | |
5700 | p = sd; | |
5701 | } else | |
5702 | p = NULL; | |
5703 | ||
1da177e4 | 5704 | sd = &per_cpu(node_domains, i); |
1da177e4 | 5705 | *sd = SD_NODE_INIT; |
9c1cfda2 JH |
5706 | sd->span = sched_domain_node_span(cpu_to_node(i)); |
5707 | sd->parent = p; | |
5708 | cpus_and(sd->span, sd->span, *cpu_map); | |
1da177e4 LT |
5709 | #endif |
5710 | ||
5711 | p = sd; | |
5712 | sd = &per_cpu(phys_domains, i); | |
5713 | group = cpu_to_phys_group(i); | |
5714 | *sd = SD_CPU_INIT; | |
5715 | sd->span = nodemask; | |
5716 | sd->parent = p; | |
5717 | sd->groups = &sched_group_phys[group]; | |
5718 | ||
1e9f28fa SS |
5719 | #ifdef CONFIG_SCHED_MC |
5720 | p = sd; | |
5721 | sd = &per_cpu(core_domains, i); | |
5722 | group = cpu_to_core_group(i); | |
5723 | *sd = SD_MC_INIT; | |
5724 | sd->span = cpu_coregroup_map(i); | |
5725 | cpus_and(sd->span, sd->span, *cpu_map); | |
5726 | sd->parent = p; | |
5727 | sd->groups = &sched_group_core[group]; | |
5728 | #endif | |
5729 | ||
1da177e4 LT |
5730 | #ifdef CONFIG_SCHED_SMT |
5731 | p = sd; | |
5732 | sd = &per_cpu(cpu_domains, i); | |
5733 | group = cpu_to_cpu_group(i); | |
5734 | *sd = SD_SIBLING_INIT; | |
5735 | sd->span = cpu_sibling_map[i]; | |
1a20ff27 | 5736 | cpus_and(sd->span, sd->span, *cpu_map); |
1da177e4 LT |
5737 | sd->parent = p; |
5738 | sd->groups = &sched_group_cpus[group]; | |
5739 | #endif | |
5740 | } | |
5741 | ||
5742 | #ifdef CONFIG_SCHED_SMT | |
5743 | /* Set up CPU (sibling) groups */ | |
9c1cfda2 | 5744 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 | 5745 | cpumask_t this_sibling_map = cpu_sibling_map[i]; |
1a20ff27 | 5746 | cpus_and(this_sibling_map, this_sibling_map, *cpu_map); |
1da177e4 LT |
5747 | if (i != first_cpu(this_sibling_map)) |
5748 | continue; | |
5749 | ||
5750 | init_sched_build_groups(sched_group_cpus, this_sibling_map, | |
5751 | &cpu_to_cpu_group); | |
5752 | } | |
5753 | #endif | |
5754 | ||
1e9f28fa SS |
5755 | #ifdef CONFIG_SCHED_MC |
5756 | /* Set up multi-core groups */ | |
5757 | for_each_cpu_mask(i, *cpu_map) { | |
5758 | cpumask_t this_core_map = cpu_coregroup_map(i); | |
5759 | cpus_and(this_core_map, this_core_map, *cpu_map); | |
5760 | if (i != first_cpu(this_core_map)) | |
5761 | continue; | |
5762 | init_sched_build_groups(sched_group_core, this_core_map, | |
5763 | &cpu_to_core_group); | |
5764 | } | |
5765 | #endif | |
5766 | ||
5767 | ||
1da177e4 LT |
5768 | /* Set up physical groups */ |
5769 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5770 | cpumask_t nodemask = node_to_cpumask(i); | |
5771 | ||
1a20ff27 | 5772 | cpus_and(nodemask, nodemask, *cpu_map); |
1da177e4 LT |
5773 | if (cpus_empty(nodemask)) |
5774 | continue; | |
5775 | ||
5776 | init_sched_build_groups(sched_group_phys, nodemask, | |
5777 | &cpu_to_phys_group); | |
5778 | } | |
5779 | ||
5780 | #ifdef CONFIG_NUMA | |
5781 | /* Set up node groups */ | |
d1b55138 JH |
5782 | if (sched_group_allnodes) |
5783 | init_sched_build_groups(sched_group_allnodes, *cpu_map, | |
5784 | &cpu_to_allnodes_group); | |
9c1cfda2 JH |
5785 | |
5786 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5787 | /* Set up node groups */ | |
5788 | struct sched_group *sg, *prev; | |
5789 | cpumask_t nodemask = node_to_cpumask(i); | |
5790 | cpumask_t domainspan; | |
5791 | cpumask_t covered = CPU_MASK_NONE; | |
5792 | int j; | |
5793 | ||
5794 | cpus_and(nodemask, nodemask, *cpu_map); | |
d1b55138 JH |
5795 | if (cpus_empty(nodemask)) { |
5796 | sched_group_nodes[i] = NULL; | |
9c1cfda2 | 5797 | continue; |
d1b55138 | 5798 | } |
9c1cfda2 JH |
5799 | |
5800 | domainspan = sched_domain_node_span(i); | |
5801 | cpus_and(domainspan, domainspan, *cpu_map); | |
5802 | ||
5803 | sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL); | |
5804 | sched_group_nodes[i] = sg; | |
5805 | for_each_cpu_mask(j, nodemask) { | |
5806 | struct sched_domain *sd; | |
5807 | sd = &per_cpu(node_domains, j); | |
5808 | sd->groups = sg; | |
5809 | if (sd->groups == NULL) { | |
5810 | /* Turn off balancing if we have no groups */ | |
5811 | sd->flags = 0; | |
5812 | } | |
5813 | } | |
5814 | if (!sg) { | |
5815 | printk(KERN_WARNING | |
5816 | "Can not alloc domain group for node %d\n", i); | |
5817 | continue; | |
5818 | } | |
5819 | sg->cpu_power = 0; | |
5820 | sg->cpumask = nodemask; | |
5821 | cpus_or(covered, covered, nodemask); | |
5822 | prev = sg; | |
5823 | ||
5824 | for (j = 0; j < MAX_NUMNODES; j++) { | |
5825 | cpumask_t tmp, notcovered; | |
5826 | int n = (i + j) % MAX_NUMNODES; | |
5827 | ||
5828 | cpus_complement(notcovered, covered); | |
5829 | cpus_and(tmp, notcovered, *cpu_map); | |
5830 | cpus_and(tmp, tmp, domainspan); | |
5831 | if (cpus_empty(tmp)) | |
5832 | break; | |
5833 | ||
5834 | nodemask = node_to_cpumask(n); | |
5835 | cpus_and(tmp, tmp, nodemask); | |
5836 | if (cpus_empty(tmp)) | |
5837 | continue; | |
5838 | ||
5839 | sg = kmalloc(sizeof(struct sched_group), GFP_KERNEL); | |
5840 | if (!sg) { | |
5841 | printk(KERN_WARNING | |
5842 | "Can not alloc domain group for node %d\n", j); | |
5843 | break; | |
5844 | } | |
5845 | sg->cpu_power = 0; | |
5846 | sg->cpumask = tmp; | |
5847 | cpus_or(covered, covered, tmp); | |
5848 | prev->next = sg; | |
5849 | prev = sg; | |
5850 | } | |
5851 | prev->next = sched_group_nodes[i]; | |
5852 | } | |
1da177e4 LT |
5853 | #endif |
5854 | ||
5855 | /* Calculate CPU power for physical packages and nodes */ | |
1a20ff27 | 5856 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5857 | int power; |
5858 | struct sched_domain *sd; | |
5859 | #ifdef CONFIG_SCHED_SMT | |
5860 | sd = &per_cpu(cpu_domains, i); | |
5861 | power = SCHED_LOAD_SCALE; | |
5862 | sd->groups->cpu_power = power; | |
5863 | #endif | |
1e9f28fa SS |
5864 | #ifdef CONFIG_SCHED_MC |
5865 | sd = &per_cpu(core_domains, i); | |
5866 | power = SCHED_LOAD_SCALE + (cpus_weight(sd->groups->cpumask)-1) | |
5867 | * SCHED_LOAD_SCALE / 10; | |
5868 | sd->groups->cpu_power = power; | |
5869 | ||
5870 | sd = &per_cpu(phys_domains, i); | |
1da177e4 | 5871 | |
1e9f28fa SS |
5872 | /* |
5873 | * This has to be < 2 * SCHED_LOAD_SCALE | |
5874 | * Lets keep it SCHED_LOAD_SCALE, so that | |
5875 | * while calculating NUMA group's cpu_power | |
5876 | * we can simply do | |
5877 | * numa_group->cpu_power += phys_group->cpu_power; | |
5878 | * | |
5879 | * See "only add power once for each physical pkg" | |
5880 | * comment below | |
5881 | */ | |
5882 | sd->groups->cpu_power = SCHED_LOAD_SCALE; | |
5883 | #else | |
1da177e4 LT |
5884 | sd = &per_cpu(phys_domains, i); |
5885 | power = SCHED_LOAD_SCALE + SCHED_LOAD_SCALE * | |
5886 | (cpus_weight(sd->groups->cpumask)-1) / 10; | |
5887 | sd->groups->cpu_power = power; | |
1e9f28fa | 5888 | #endif |
1da177e4 LT |
5889 | } |
5890 | ||
9c1cfda2 | 5891 | #ifdef CONFIG_NUMA |
08069033 SS |
5892 | for (i = 0; i < MAX_NUMNODES; i++) |
5893 | init_numa_sched_groups_power(sched_group_nodes[i]); | |
9c1cfda2 | 5894 | |
08069033 | 5895 | init_numa_sched_groups_power(sched_group_allnodes); |
9c1cfda2 JH |
5896 | #endif |
5897 | ||
1da177e4 | 5898 | /* Attach the domains */ |
1a20ff27 | 5899 | for_each_cpu_mask(i, *cpu_map) { |
1da177e4 LT |
5900 | struct sched_domain *sd; |
5901 | #ifdef CONFIG_SCHED_SMT | |
5902 | sd = &per_cpu(cpu_domains, i); | |
1e9f28fa SS |
5903 | #elif defined(CONFIG_SCHED_MC) |
5904 | sd = &per_cpu(core_domains, i); | |
1da177e4 LT |
5905 | #else |
5906 | sd = &per_cpu(phys_domains, i); | |
5907 | #endif | |
5908 | cpu_attach_domain(sd, i); | |
5909 | } | |
198e2f18 | 5910 | /* |
5911 | * Tune cache-hot values: | |
5912 | */ | |
5913 | calibrate_migration_costs(cpu_map); | |
1da177e4 | 5914 | } |
1a20ff27 DG |
5915 | /* |
5916 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. | |
5917 | */ | |
9c1cfda2 | 5918 | static void arch_init_sched_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
5919 | { |
5920 | cpumask_t cpu_default_map; | |
1da177e4 | 5921 | |
1a20ff27 DG |
5922 | /* |
5923 | * Setup mask for cpus without special case scheduling requirements. | |
5924 | * For now this just excludes isolated cpus, but could be used to | |
5925 | * exclude other special cases in the future. | |
5926 | */ | |
5927 | cpus_andnot(cpu_default_map, *cpu_map, cpu_isolated_map); | |
5928 | ||
5929 | build_sched_domains(&cpu_default_map); | |
5930 | } | |
5931 | ||
5932 | static void arch_destroy_sched_domains(const cpumask_t *cpu_map) | |
1da177e4 | 5933 | { |
9c1cfda2 JH |
5934 | #ifdef CONFIG_NUMA |
5935 | int i; | |
d1b55138 | 5936 | int cpu; |
1da177e4 | 5937 | |
d1b55138 JH |
5938 | for_each_cpu_mask(cpu, *cpu_map) { |
5939 | struct sched_group *sched_group_allnodes | |
5940 | = sched_group_allnodes_bycpu[cpu]; | |
5941 | struct sched_group **sched_group_nodes | |
5942 | = sched_group_nodes_bycpu[cpu]; | |
9c1cfda2 | 5943 | |
d1b55138 JH |
5944 | if (sched_group_allnodes) { |
5945 | kfree(sched_group_allnodes); | |
5946 | sched_group_allnodes_bycpu[cpu] = NULL; | |
5947 | } | |
5948 | ||
5949 | if (!sched_group_nodes) | |
9c1cfda2 | 5950 | continue; |
d1b55138 JH |
5951 | |
5952 | for (i = 0; i < MAX_NUMNODES; i++) { | |
5953 | cpumask_t nodemask = node_to_cpumask(i); | |
5954 | struct sched_group *oldsg, *sg = sched_group_nodes[i]; | |
5955 | ||
5956 | cpus_and(nodemask, nodemask, *cpu_map); | |
5957 | if (cpus_empty(nodemask)) | |
5958 | continue; | |
5959 | ||
5960 | if (sg == NULL) | |
5961 | continue; | |
5962 | sg = sg->next; | |
9c1cfda2 | 5963 | next_sg: |
d1b55138 JH |
5964 | oldsg = sg; |
5965 | sg = sg->next; | |
5966 | kfree(oldsg); | |
5967 | if (oldsg != sched_group_nodes[i]) | |
5968 | goto next_sg; | |
5969 | } | |
5970 | kfree(sched_group_nodes); | |
5971 | sched_group_nodes_bycpu[cpu] = NULL; | |
9c1cfda2 JH |
5972 | } |
5973 | #endif | |
5974 | } | |
1da177e4 | 5975 | |
1a20ff27 DG |
5976 | /* |
5977 | * Detach sched domains from a group of cpus specified in cpu_map | |
5978 | * These cpus will now be attached to the NULL domain | |
5979 | */ | |
858119e1 | 5980 | static void detach_destroy_domains(const cpumask_t *cpu_map) |
1a20ff27 DG |
5981 | { |
5982 | int i; | |
5983 | ||
5984 | for_each_cpu_mask(i, *cpu_map) | |
5985 | cpu_attach_domain(NULL, i); | |
5986 | synchronize_sched(); | |
5987 | arch_destroy_sched_domains(cpu_map); | |
5988 | } | |
5989 | ||
5990 | /* | |
5991 | * Partition sched domains as specified by the cpumasks below. | |
5992 | * This attaches all cpus from the cpumasks to the NULL domain, | |
5993 | * waits for a RCU quiescent period, recalculates sched | |
5994 | * domain information and then attaches them back to the | |
5995 | * correct sched domains | |
5996 | * Call with hotplug lock held | |
5997 | */ | |
5998 | void partition_sched_domains(cpumask_t *partition1, cpumask_t *partition2) | |
5999 | { | |
6000 | cpumask_t change_map; | |
6001 | ||
6002 | cpus_and(*partition1, *partition1, cpu_online_map); | |
6003 | cpus_and(*partition2, *partition2, cpu_online_map); | |
6004 | cpus_or(change_map, *partition1, *partition2); | |
6005 | ||
6006 | /* Detach sched domains from all of the affected cpus */ | |
6007 | detach_destroy_domains(&change_map); | |
6008 | if (!cpus_empty(*partition1)) | |
6009 | build_sched_domains(partition1); | |
6010 | if (!cpus_empty(*partition2)) | |
6011 | build_sched_domains(partition2); | |
6012 | } | |
6013 | ||
1da177e4 LT |
6014 | #ifdef CONFIG_HOTPLUG_CPU |
6015 | /* | |
6016 | * Force a reinitialization of the sched domains hierarchy. The domains | |
6017 | * and groups cannot be updated in place without racing with the balancing | |
41c7ce9a | 6018 | * code, so we temporarily attach all running cpus to the NULL domain |
1da177e4 LT |
6019 | * which will prevent rebalancing while the sched domains are recalculated. |
6020 | */ | |
6021 | static int update_sched_domains(struct notifier_block *nfb, | |
6022 | unsigned long action, void *hcpu) | |
6023 | { | |
1da177e4 LT |
6024 | switch (action) { |
6025 | case CPU_UP_PREPARE: | |
6026 | case CPU_DOWN_PREPARE: | |
1a20ff27 | 6027 | detach_destroy_domains(&cpu_online_map); |
1da177e4 LT |
6028 | return NOTIFY_OK; |
6029 | ||
6030 | case CPU_UP_CANCELED: | |
6031 | case CPU_DOWN_FAILED: | |
6032 | case CPU_ONLINE: | |
6033 | case CPU_DEAD: | |
6034 | /* | |
6035 | * Fall through and re-initialise the domains. | |
6036 | */ | |
6037 | break; | |
6038 | default: | |
6039 | return NOTIFY_DONE; | |
6040 | } | |
6041 | ||
6042 | /* The hotplug lock is already held by cpu_up/cpu_down */ | |
1a20ff27 | 6043 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6044 | |
6045 | return NOTIFY_OK; | |
6046 | } | |
6047 | #endif | |
6048 | ||
6049 | void __init sched_init_smp(void) | |
6050 | { | |
6051 | lock_cpu_hotplug(); | |
1a20ff27 | 6052 | arch_init_sched_domains(&cpu_online_map); |
1da177e4 LT |
6053 | unlock_cpu_hotplug(); |
6054 | /* XXX: Theoretical race here - CPU may be hotplugged now */ | |
6055 | hotcpu_notifier(update_sched_domains, 0); | |
6056 | } | |
6057 | #else | |
6058 | void __init sched_init_smp(void) | |
6059 | { | |
6060 | } | |
6061 | #endif /* CONFIG_SMP */ | |
6062 | ||
6063 | int in_sched_functions(unsigned long addr) | |
6064 | { | |
6065 | /* Linker adds these: start and end of __sched functions */ | |
6066 | extern char __sched_text_start[], __sched_text_end[]; | |
6067 | return in_lock_functions(addr) || | |
6068 | (addr >= (unsigned long)__sched_text_start | |
6069 | && addr < (unsigned long)__sched_text_end); | |
6070 | } | |
6071 | ||
6072 | void __init sched_init(void) | |
6073 | { | |
6074 | runqueue_t *rq; | |
6075 | int i, j, k; | |
6076 | ||
0a945022 | 6077 | for_each_possible_cpu(i) { |
1da177e4 LT |
6078 | prio_array_t *array; |
6079 | ||
6080 | rq = cpu_rq(i); | |
6081 | spin_lock_init(&rq->lock); | |
7897986b | 6082 | rq->nr_running = 0; |
1da177e4 LT |
6083 | rq->active = rq->arrays; |
6084 | rq->expired = rq->arrays + 1; | |
6085 | rq->best_expired_prio = MAX_PRIO; | |
6086 | ||
6087 | #ifdef CONFIG_SMP | |
41c7ce9a | 6088 | rq->sd = NULL; |
7897986b NP |
6089 | for (j = 1; j < 3; j++) |
6090 | rq->cpu_load[j] = 0; | |
1da177e4 LT |
6091 | rq->active_balance = 0; |
6092 | rq->push_cpu = 0; | |
6093 | rq->migration_thread = NULL; | |
6094 | INIT_LIST_HEAD(&rq->migration_queue); | |
6095 | #endif | |
6096 | atomic_set(&rq->nr_iowait, 0); | |
6097 | ||
6098 | for (j = 0; j < 2; j++) { | |
6099 | array = rq->arrays + j; | |
6100 | for (k = 0; k < MAX_PRIO; k++) { | |
6101 | INIT_LIST_HEAD(array->queue + k); | |
6102 | __clear_bit(k, array->bitmap); | |
6103 | } | |
6104 | // delimiter for bitsearch | |
6105 | __set_bit(MAX_PRIO, array->bitmap); | |
6106 | } | |
6107 | } | |
6108 | ||
6109 | /* | |
6110 | * The boot idle thread does lazy MMU switching as well: | |
6111 | */ | |
6112 | atomic_inc(&init_mm.mm_count); | |
6113 | enter_lazy_tlb(&init_mm, current); | |
6114 | ||
6115 | /* | |
6116 | * Make us the idle thread. Technically, schedule() should not be | |
6117 | * called from this thread, however somewhere below it might be, | |
6118 | * but because we are the idle thread, we just pick up running again | |
6119 | * when this runqueue becomes "idle". | |
6120 | */ | |
6121 | init_idle(current, smp_processor_id()); | |
6122 | } | |
6123 | ||
6124 | #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP | |
6125 | void __might_sleep(char *file, int line) | |
6126 | { | |
6127 | #if defined(in_atomic) | |
6128 | static unsigned long prev_jiffy; /* ratelimiting */ | |
6129 | ||
6130 | if ((in_atomic() || irqs_disabled()) && | |
6131 | system_state == SYSTEM_RUNNING && !oops_in_progress) { | |
6132 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6133 | return; | |
6134 | prev_jiffy = jiffies; | |
91368d73 | 6135 | printk(KERN_ERR "BUG: sleeping function called from invalid" |
1da177e4 LT |
6136 | " context at %s:%d\n", file, line); |
6137 | printk("in_atomic():%d, irqs_disabled():%d\n", | |
6138 | in_atomic(), irqs_disabled()); | |
6139 | dump_stack(); | |
6140 | } | |
6141 | #endif | |
6142 | } | |
6143 | EXPORT_SYMBOL(__might_sleep); | |
6144 | #endif | |
6145 | ||
6146 | #ifdef CONFIG_MAGIC_SYSRQ | |
6147 | void normalize_rt_tasks(void) | |
6148 | { | |
6149 | struct task_struct *p; | |
6150 | prio_array_t *array; | |
6151 | unsigned long flags; | |
6152 | runqueue_t *rq; | |
6153 | ||
6154 | read_lock_irq(&tasklist_lock); | |
c96d145e | 6155 | for_each_process(p) { |
1da177e4 LT |
6156 | if (!rt_task(p)) |
6157 | continue; | |
6158 | ||
6159 | rq = task_rq_lock(p, &flags); | |
6160 | ||
6161 | array = p->array; | |
6162 | if (array) | |
6163 | deactivate_task(p, task_rq(p)); | |
6164 | __setscheduler(p, SCHED_NORMAL, 0); | |
6165 | if (array) { | |
6166 | __activate_task(p, task_rq(p)); | |
6167 | resched_task(rq->curr); | |
6168 | } | |
6169 | ||
6170 | task_rq_unlock(rq, &flags); | |
6171 | } | |
6172 | read_unlock_irq(&tasklist_lock); | |
6173 | } | |
6174 | ||
6175 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a LT |
6176 | |
6177 | #ifdef CONFIG_IA64 | |
6178 | /* | |
6179 | * These functions are only useful for the IA64 MCA handling. | |
6180 | * | |
6181 | * They can only be called when the whole system has been | |
6182 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6183 | * activity can take place. Using them for anything else would | |
6184 | * be a serious bug, and as a result, they aren't even visible | |
6185 | * under any other configuration. | |
6186 | */ | |
6187 | ||
6188 | /** | |
6189 | * curr_task - return the current task for a given cpu. | |
6190 | * @cpu: the processor in question. | |
6191 | * | |
6192 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6193 | */ | |
6194 | task_t *curr_task(int cpu) | |
6195 | { | |
6196 | return cpu_curr(cpu); | |
6197 | } | |
6198 | ||
6199 | /** | |
6200 | * set_curr_task - set the current task for a given cpu. | |
6201 | * @cpu: the processor in question. | |
6202 | * @p: the task pointer to set. | |
6203 | * | |
6204 | * Description: This function must only be used when non-maskable interrupts | |
6205 | * are serviced on a separate stack. It allows the architecture to switch the | |
6206 | * notion of the current task on a cpu in a non-blocking manner. This function | |
6207 | * must be called with all CPU's synchronized, and interrupts disabled, the | |
6208 | * and caller must save the original value of the current task (see | |
6209 | * curr_task() above) and restore that value before reenabling interrupts and | |
6210 | * re-starting the system. | |
6211 | * | |
6212 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6213 | */ | |
6214 | void set_curr_task(int cpu, task_t *p) | |
6215 | { | |
6216 | cpu_curr(cpu) = p; | |
6217 | } | |
6218 | ||
6219 | #endif |