Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
391e43da | 2 | * kernel/sched/core.c |
1da177e4 LT |
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 | |
c31f2e8a IM |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. | |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements | |
22 | * by Peter Williams | |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith | |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri | |
b9131769 IM |
25 | * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, |
26 | * Thomas Gleixner, Mike Kravetz | |
1da177e4 LT |
27 | */ |
28 | ||
29 | #include <linux/mm.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/nmi.h> | |
32 | #include <linux/init.h> | |
dff06c15 | 33 | #include <linux/uaccess.h> |
1da177e4 | 34 | #include <linux/highmem.h> |
1da177e4 LT |
35 | #include <asm/mmu_context.h> |
36 | #include <linux/interrupt.h> | |
c59ede7b | 37 | #include <linux/capability.h> |
1da177e4 LT |
38 | #include <linux/completion.h> |
39 | #include <linux/kernel_stat.h> | |
9a11b49a | 40 | #include <linux/debug_locks.h> |
cdd6c482 | 41 | #include <linux/perf_event.h> |
1da177e4 LT |
42 | #include <linux/security.h> |
43 | #include <linux/notifier.h> | |
44 | #include <linux/profile.h> | |
7dfb7103 | 45 | #include <linux/freezer.h> |
198e2f18 | 46 | #include <linux/vmalloc.h> |
1da177e4 LT |
47 | #include <linux/blkdev.h> |
48 | #include <linux/delay.h> | |
b488893a | 49 | #include <linux/pid_namespace.h> |
1da177e4 LT |
50 | #include <linux/smp.h> |
51 | #include <linux/threads.h> | |
52 | #include <linux/timer.h> | |
53 | #include <linux/rcupdate.h> | |
54 | #include <linux/cpu.h> | |
55 | #include <linux/cpuset.h> | |
56 | #include <linux/percpu.h> | |
b5aadf7f | 57 | #include <linux/proc_fs.h> |
1da177e4 | 58 | #include <linux/seq_file.h> |
e692ab53 | 59 | #include <linux/sysctl.h> |
1da177e4 LT |
60 | #include <linux/syscalls.h> |
61 | #include <linux/times.h> | |
8f0ab514 | 62 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 63 | #include <linux/kprobes.h> |
0ff92245 | 64 | #include <linux/delayacct.h> |
dff06c15 | 65 | #include <linux/unistd.h> |
f5ff8422 | 66 | #include <linux/pagemap.h> |
8f4d37ec | 67 | #include <linux/hrtimer.h> |
30914a58 | 68 | #include <linux/tick.h> |
f00b45c1 PZ |
69 | #include <linux/debugfs.h> |
70 | #include <linux/ctype.h> | |
6cd8a4bb | 71 | #include <linux/ftrace.h> |
5a0e3ad6 | 72 | #include <linux/slab.h> |
f1c6f1a7 | 73 | #include <linux/init_task.h> |
40401530 | 74 | #include <linux/binfmts.h> |
91d1aa43 | 75 | #include <linux/context_tracking.h> |
1da177e4 | 76 | |
96f951ed | 77 | #include <asm/switch_to.h> |
5517d86b | 78 | #include <asm/tlb.h> |
838225b4 | 79 | #include <asm/irq_regs.h> |
db7e527d | 80 | #include <asm/mutex.h> |
e6e6685a GC |
81 | #ifdef CONFIG_PARAVIRT |
82 | #include <asm/paravirt.h> | |
83 | #endif | |
1da177e4 | 84 | |
029632fb | 85 | #include "sched.h" |
ea138446 | 86 | #include "../workqueue_internal.h" |
29d5e047 | 87 | #include "../smpboot.h" |
6e0534f2 | 88 | |
a8d154b0 | 89 | #define CREATE_TRACE_POINTS |
ad8d75ff | 90 | #include <trace/events/sched.h> |
a8d154b0 | 91 | |
029632fb | 92 | void start_bandwidth_timer(struct hrtimer *period_timer, ktime_t period) |
d0b27fa7 | 93 | { |
58088ad0 PT |
94 | unsigned long delta; |
95 | ktime_t soft, hard, now; | |
d0b27fa7 | 96 | |
58088ad0 PT |
97 | for (;;) { |
98 | if (hrtimer_active(period_timer)) | |
99 | break; | |
100 | ||
101 | now = hrtimer_cb_get_time(period_timer); | |
102 | hrtimer_forward(period_timer, now, period); | |
d0b27fa7 | 103 | |
58088ad0 PT |
104 | soft = hrtimer_get_softexpires(period_timer); |
105 | hard = hrtimer_get_expires(period_timer); | |
106 | delta = ktime_to_ns(ktime_sub(hard, soft)); | |
107 | __hrtimer_start_range_ns(period_timer, soft, delta, | |
108 | HRTIMER_MODE_ABS_PINNED, 0); | |
109 | } | |
110 | } | |
111 | ||
029632fb PZ |
112 | DEFINE_MUTEX(sched_domains_mutex); |
113 | DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); | |
dc61b1d6 | 114 | |
fe44d621 | 115 | static void update_rq_clock_task(struct rq *rq, s64 delta); |
305e6835 | 116 | |
029632fb | 117 | void update_rq_clock(struct rq *rq) |
3e51f33f | 118 | { |
fe44d621 | 119 | s64 delta; |
305e6835 | 120 | |
61eadef6 | 121 | if (rq->skip_clock_update > 0) |
f26f9aff | 122 | return; |
aa483808 | 123 | |
fe44d621 PZ |
124 | delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; |
125 | rq->clock += delta; | |
126 | update_rq_clock_task(rq, delta); | |
3e51f33f PZ |
127 | } |
128 | ||
bf5c91ba IM |
129 | /* |
130 | * Debugging: various feature bits | |
131 | */ | |
f00b45c1 | 132 | |
f00b45c1 PZ |
133 | #define SCHED_FEAT(name, enabled) \ |
134 | (1UL << __SCHED_FEAT_##name) * enabled | | |
135 | ||
bf5c91ba | 136 | const_debug unsigned int sysctl_sched_features = |
391e43da | 137 | #include "features.h" |
f00b45c1 PZ |
138 | 0; |
139 | ||
140 | #undef SCHED_FEAT | |
141 | ||
142 | #ifdef CONFIG_SCHED_DEBUG | |
143 | #define SCHED_FEAT(name, enabled) \ | |
144 | #name , | |
145 | ||
1292531f | 146 | static const char * const sched_feat_names[] = { |
391e43da | 147 | #include "features.h" |
f00b45c1 PZ |
148 | }; |
149 | ||
150 | #undef SCHED_FEAT | |
151 | ||
34f3a814 | 152 | static int sched_feat_show(struct seq_file *m, void *v) |
f00b45c1 | 153 | { |
f00b45c1 PZ |
154 | int i; |
155 | ||
f8b6d1cc | 156 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
34f3a814 LZ |
157 | if (!(sysctl_sched_features & (1UL << i))) |
158 | seq_puts(m, "NO_"); | |
159 | seq_printf(m, "%s ", sched_feat_names[i]); | |
f00b45c1 | 160 | } |
34f3a814 | 161 | seq_puts(m, "\n"); |
f00b45c1 | 162 | |
34f3a814 | 163 | return 0; |
f00b45c1 PZ |
164 | } |
165 | ||
f8b6d1cc PZ |
166 | #ifdef HAVE_JUMP_LABEL |
167 | ||
c5905afb IM |
168 | #define jump_label_key__true STATIC_KEY_INIT_TRUE |
169 | #define jump_label_key__false STATIC_KEY_INIT_FALSE | |
f8b6d1cc PZ |
170 | |
171 | #define SCHED_FEAT(name, enabled) \ | |
172 | jump_label_key__##enabled , | |
173 | ||
c5905afb | 174 | struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { |
f8b6d1cc PZ |
175 | #include "features.h" |
176 | }; | |
177 | ||
178 | #undef SCHED_FEAT | |
179 | ||
180 | static void sched_feat_disable(int i) | |
181 | { | |
c5905afb IM |
182 | if (static_key_enabled(&sched_feat_keys[i])) |
183 | static_key_slow_dec(&sched_feat_keys[i]); | |
f8b6d1cc PZ |
184 | } |
185 | ||
186 | static void sched_feat_enable(int i) | |
187 | { | |
c5905afb IM |
188 | if (!static_key_enabled(&sched_feat_keys[i])) |
189 | static_key_slow_inc(&sched_feat_keys[i]); | |
f8b6d1cc PZ |
190 | } |
191 | #else | |
192 | static void sched_feat_disable(int i) { }; | |
193 | static void sched_feat_enable(int i) { }; | |
194 | #endif /* HAVE_JUMP_LABEL */ | |
195 | ||
1a687c2e | 196 | static int sched_feat_set(char *cmp) |
f00b45c1 | 197 | { |
f00b45c1 | 198 | int i; |
1a687c2e | 199 | int neg = 0; |
f00b45c1 | 200 | |
524429c3 | 201 | if (strncmp(cmp, "NO_", 3) == 0) { |
f00b45c1 PZ |
202 | neg = 1; |
203 | cmp += 3; | |
204 | } | |
205 | ||
f8b6d1cc | 206 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
7740191c | 207 | if (strcmp(cmp, sched_feat_names[i]) == 0) { |
f8b6d1cc | 208 | if (neg) { |
f00b45c1 | 209 | sysctl_sched_features &= ~(1UL << i); |
f8b6d1cc PZ |
210 | sched_feat_disable(i); |
211 | } else { | |
f00b45c1 | 212 | sysctl_sched_features |= (1UL << i); |
f8b6d1cc PZ |
213 | sched_feat_enable(i); |
214 | } | |
f00b45c1 PZ |
215 | break; |
216 | } | |
217 | } | |
218 | ||
1a687c2e MG |
219 | return i; |
220 | } | |
221 | ||
222 | static ssize_t | |
223 | sched_feat_write(struct file *filp, const char __user *ubuf, | |
224 | size_t cnt, loff_t *ppos) | |
225 | { | |
226 | char buf[64]; | |
227 | char *cmp; | |
228 | int i; | |
229 | ||
230 | if (cnt > 63) | |
231 | cnt = 63; | |
232 | ||
233 | if (copy_from_user(&buf, ubuf, cnt)) | |
234 | return -EFAULT; | |
235 | ||
236 | buf[cnt] = 0; | |
237 | cmp = strstrip(buf); | |
238 | ||
239 | i = sched_feat_set(cmp); | |
f8b6d1cc | 240 | if (i == __SCHED_FEAT_NR) |
f00b45c1 PZ |
241 | return -EINVAL; |
242 | ||
42994724 | 243 | *ppos += cnt; |
f00b45c1 PZ |
244 | |
245 | return cnt; | |
246 | } | |
247 | ||
34f3a814 LZ |
248 | static int sched_feat_open(struct inode *inode, struct file *filp) |
249 | { | |
250 | return single_open(filp, sched_feat_show, NULL); | |
251 | } | |
252 | ||
828c0950 | 253 | static const struct file_operations sched_feat_fops = { |
34f3a814 LZ |
254 | .open = sched_feat_open, |
255 | .write = sched_feat_write, | |
256 | .read = seq_read, | |
257 | .llseek = seq_lseek, | |
258 | .release = single_release, | |
f00b45c1 PZ |
259 | }; |
260 | ||
261 | static __init int sched_init_debug(void) | |
262 | { | |
f00b45c1 PZ |
263 | debugfs_create_file("sched_features", 0644, NULL, NULL, |
264 | &sched_feat_fops); | |
265 | ||
266 | return 0; | |
267 | } | |
268 | late_initcall(sched_init_debug); | |
f8b6d1cc | 269 | #endif /* CONFIG_SCHED_DEBUG */ |
bf5c91ba | 270 | |
b82d9fdd PZ |
271 | /* |
272 | * Number of tasks to iterate in a single balance run. | |
273 | * Limited because this is done with IRQs disabled. | |
274 | */ | |
275 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
276 | ||
e9e9250b PZ |
277 | /* |
278 | * period over which we average the RT time consumption, measured | |
279 | * in ms. | |
280 | * | |
281 | * default: 1s | |
282 | */ | |
283 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; | |
284 | ||
fa85ae24 | 285 | /* |
9f0c1e56 | 286 | * period over which we measure -rt task cpu usage in us. |
fa85ae24 PZ |
287 | * default: 1s |
288 | */ | |
9f0c1e56 | 289 | unsigned int sysctl_sched_rt_period = 1000000; |
fa85ae24 | 290 | |
029632fb | 291 | __read_mostly int scheduler_running; |
6892b75e | 292 | |
9f0c1e56 PZ |
293 | /* |
294 | * part of the period that we allow rt tasks to run in us. | |
295 | * default: 0.95s | |
296 | */ | |
297 | int sysctl_sched_rt_runtime = 950000; | |
fa85ae24 | 298 | |
fa85ae24 | 299 | |
1da177e4 | 300 | |
0970d299 | 301 | /* |
0122ec5b | 302 | * __task_rq_lock - lock the rq @p resides on. |
b29739f9 | 303 | */ |
70b97a7f | 304 | static inline struct rq *__task_rq_lock(struct task_struct *p) |
b29739f9 IM |
305 | __acquires(rq->lock) |
306 | { | |
0970d299 PZ |
307 | struct rq *rq; |
308 | ||
0122ec5b PZ |
309 | lockdep_assert_held(&p->pi_lock); |
310 | ||
3a5c359a | 311 | for (;;) { |
0970d299 | 312 | rq = task_rq(p); |
05fa785c | 313 | raw_spin_lock(&rq->lock); |
65cc8e48 | 314 | if (likely(rq == task_rq(p))) |
3a5c359a | 315 | return rq; |
05fa785c | 316 | raw_spin_unlock(&rq->lock); |
b29739f9 | 317 | } |
b29739f9 IM |
318 | } |
319 | ||
1da177e4 | 320 | /* |
0122ec5b | 321 | * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. |
1da177e4 | 322 | */ |
70b97a7f | 323 | static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
0122ec5b | 324 | __acquires(p->pi_lock) |
1da177e4 LT |
325 | __acquires(rq->lock) |
326 | { | |
70b97a7f | 327 | struct rq *rq; |
1da177e4 | 328 | |
3a5c359a | 329 | for (;;) { |
0122ec5b | 330 | raw_spin_lock_irqsave(&p->pi_lock, *flags); |
3a5c359a | 331 | rq = task_rq(p); |
05fa785c | 332 | raw_spin_lock(&rq->lock); |
65cc8e48 | 333 | if (likely(rq == task_rq(p))) |
3a5c359a | 334 | return rq; |
0122ec5b PZ |
335 | raw_spin_unlock(&rq->lock); |
336 | raw_spin_unlock_irqrestore(&p->pi_lock, *flags); | |
1da177e4 | 337 | } |
1da177e4 LT |
338 | } |
339 | ||
a9957449 | 340 | static void __task_rq_unlock(struct rq *rq) |
b29739f9 IM |
341 | __releases(rq->lock) |
342 | { | |
05fa785c | 343 | raw_spin_unlock(&rq->lock); |
b29739f9 IM |
344 | } |
345 | ||
0122ec5b PZ |
346 | static inline void |
347 | task_rq_unlock(struct rq *rq, struct task_struct *p, unsigned long *flags) | |
1da177e4 | 348 | __releases(rq->lock) |
0122ec5b | 349 | __releases(p->pi_lock) |
1da177e4 | 350 | { |
0122ec5b PZ |
351 | raw_spin_unlock(&rq->lock); |
352 | raw_spin_unlock_irqrestore(&p->pi_lock, *flags); | |
1da177e4 LT |
353 | } |
354 | ||
1da177e4 | 355 | /* |
cc2a73b5 | 356 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 357 | */ |
a9957449 | 358 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
359 | __acquires(rq->lock) |
360 | { | |
70b97a7f | 361 | struct rq *rq; |
1da177e4 LT |
362 | |
363 | local_irq_disable(); | |
364 | rq = this_rq(); | |
05fa785c | 365 | raw_spin_lock(&rq->lock); |
1da177e4 LT |
366 | |
367 | return rq; | |
368 | } | |
369 | ||
8f4d37ec PZ |
370 | #ifdef CONFIG_SCHED_HRTICK |
371 | /* | |
372 | * Use HR-timers to deliver accurate preemption points. | |
8f4d37ec | 373 | */ |
8f4d37ec | 374 | |
8f4d37ec PZ |
375 | static void hrtick_clear(struct rq *rq) |
376 | { | |
377 | if (hrtimer_active(&rq->hrtick_timer)) | |
378 | hrtimer_cancel(&rq->hrtick_timer); | |
379 | } | |
380 | ||
8f4d37ec PZ |
381 | /* |
382 | * High-resolution timer tick. | |
383 | * Runs from hardirq context with interrupts disabled. | |
384 | */ | |
385 | static enum hrtimer_restart hrtick(struct hrtimer *timer) | |
386 | { | |
387 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); | |
388 | ||
389 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
390 | ||
05fa785c | 391 | raw_spin_lock(&rq->lock); |
3e51f33f | 392 | update_rq_clock(rq); |
8f4d37ec | 393 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
05fa785c | 394 | raw_spin_unlock(&rq->lock); |
8f4d37ec PZ |
395 | |
396 | return HRTIMER_NORESTART; | |
397 | } | |
398 | ||
95e904c7 | 399 | #ifdef CONFIG_SMP |
971ee28c PZ |
400 | |
401 | static int __hrtick_restart(struct rq *rq) | |
402 | { | |
403 | struct hrtimer *timer = &rq->hrtick_timer; | |
404 | ktime_t time = hrtimer_get_softexpires(timer); | |
405 | ||
406 | return __hrtimer_start_range_ns(timer, time, 0, HRTIMER_MODE_ABS_PINNED, 0); | |
407 | } | |
408 | ||
31656519 PZ |
409 | /* |
410 | * called from hardirq (IPI) context | |
411 | */ | |
412 | static void __hrtick_start(void *arg) | |
b328ca18 | 413 | { |
31656519 | 414 | struct rq *rq = arg; |
b328ca18 | 415 | |
05fa785c | 416 | raw_spin_lock(&rq->lock); |
971ee28c | 417 | __hrtick_restart(rq); |
31656519 | 418 | rq->hrtick_csd_pending = 0; |
05fa785c | 419 | raw_spin_unlock(&rq->lock); |
b328ca18 PZ |
420 | } |
421 | ||
31656519 PZ |
422 | /* |
423 | * Called to set the hrtick timer state. | |
424 | * | |
425 | * called with rq->lock held and irqs disabled | |
426 | */ | |
029632fb | 427 | void hrtick_start(struct rq *rq, u64 delay) |
b328ca18 | 428 | { |
31656519 PZ |
429 | struct hrtimer *timer = &rq->hrtick_timer; |
430 | ktime_t time = ktime_add_ns(timer->base->get_time(), delay); | |
b328ca18 | 431 | |
cc584b21 | 432 | hrtimer_set_expires(timer, time); |
31656519 PZ |
433 | |
434 | if (rq == this_rq()) { | |
971ee28c | 435 | __hrtick_restart(rq); |
31656519 | 436 | } else if (!rq->hrtick_csd_pending) { |
6e275637 | 437 | __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0); |
31656519 PZ |
438 | rq->hrtick_csd_pending = 1; |
439 | } | |
b328ca18 PZ |
440 | } |
441 | ||
442 | static int | |
443 | hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
444 | { | |
445 | int cpu = (int)(long)hcpu; | |
446 | ||
447 | switch (action) { | |
448 | case CPU_UP_CANCELED: | |
449 | case CPU_UP_CANCELED_FROZEN: | |
450 | case CPU_DOWN_PREPARE: | |
451 | case CPU_DOWN_PREPARE_FROZEN: | |
452 | case CPU_DEAD: | |
453 | case CPU_DEAD_FROZEN: | |
31656519 | 454 | hrtick_clear(cpu_rq(cpu)); |
b328ca18 PZ |
455 | return NOTIFY_OK; |
456 | } | |
457 | ||
458 | return NOTIFY_DONE; | |
459 | } | |
460 | ||
fa748203 | 461 | static __init void init_hrtick(void) |
b328ca18 PZ |
462 | { |
463 | hotcpu_notifier(hotplug_hrtick, 0); | |
464 | } | |
31656519 PZ |
465 | #else |
466 | /* | |
467 | * Called to set the hrtick timer state. | |
468 | * | |
469 | * called with rq->lock held and irqs disabled | |
470 | */ | |
029632fb | 471 | void hrtick_start(struct rq *rq, u64 delay) |
31656519 | 472 | { |
7f1e2ca9 | 473 | __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0, |
5c333864 | 474 | HRTIMER_MODE_REL_PINNED, 0); |
31656519 | 475 | } |
b328ca18 | 476 | |
006c75f1 | 477 | static inline void init_hrtick(void) |
8f4d37ec | 478 | { |
8f4d37ec | 479 | } |
31656519 | 480 | #endif /* CONFIG_SMP */ |
8f4d37ec | 481 | |
31656519 | 482 | static void init_rq_hrtick(struct rq *rq) |
8f4d37ec | 483 | { |
31656519 PZ |
484 | #ifdef CONFIG_SMP |
485 | rq->hrtick_csd_pending = 0; | |
8f4d37ec | 486 | |
31656519 PZ |
487 | rq->hrtick_csd.flags = 0; |
488 | rq->hrtick_csd.func = __hrtick_start; | |
489 | rq->hrtick_csd.info = rq; | |
490 | #endif | |
8f4d37ec | 491 | |
31656519 PZ |
492 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
493 | rq->hrtick_timer.function = hrtick; | |
8f4d37ec | 494 | } |
006c75f1 | 495 | #else /* CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
496 | static inline void hrtick_clear(struct rq *rq) |
497 | { | |
498 | } | |
499 | ||
8f4d37ec PZ |
500 | static inline void init_rq_hrtick(struct rq *rq) |
501 | { | |
502 | } | |
503 | ||
b328ca18 PZ |
504 | static inline void init_hrtick(void) |
505 | { | |
506 | } | |
006c75f1 | 507 | #endif /* CONFIG_SCHED_HRTICK */ |
8f4d37ec | 508 | |
c24d20db IM |
509 | /* |
510 | * resched_task - mark a task 'to be rescheduled now'. | |
511 | * | |
512 | * On UP this means the setting of the need_resched flag, on SMP it | |
513 | * might also involve a cross-CPU call to trigger the scheduler on | |
514 | * the target CPU. | |
515 | */ | |
516 | #ifdef CONFIG_SMP | |
029632fb | 517 | void resched_task(struct task_struct *p) |
c24d20db IM |
518 | { |
519 | int cpu; | |
520 | ||
05fa785c | 521 | assert_raw_spin_locked(&task_rq(p)->lock); |
c24d20db | 522 | |
5ed0cec0 | 523 | if (test_tsk_need_resched(p)) |
c24d20db IM |
524 | return; |
525 | ||
5ed0cec0 | 526 | set_tsk_need_resched(p); |
c24d20db IM |
527 | |
528 | cpu = task_cpu(p); | |
529 | if (cpu == smp_processor_id()) | |
530 | return; | |
531 | ||
532 | /* NEED_RESCHED must be visible before we test polling */ | |
533 | smp_mb(); | |
534 | if (!tsk_is_polling(p)) | |
535 | smp_send_reschedule(cpu); | |
536 | } | |
537 | ||
029632fb | 538 | void resched_cpu(int cpu) |
c24d20db IM |
539 | { |
540 | struct rq *rq = cpu_rq(cpu); | |
541 | unsigned long flags; | |
542 | ||
05fa785c | 543 | if (!raw_spin_trylock_irqsave(&rq->lock, flags)) |
c24d20db IM |
544 | return; |
545 | resched_task(cpu_curr(cpu)); | |
05fa785c | 546 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
c24d20db | 547 | } |
06d8308c | 548 | |
3451d024 | 549 | #ifdef CONFIG_NO_HZ_COMMON |
83cd4fe2 VP |
550 | /* |
551 | * In the semi idle case, use the nearest busy cpu for migrating timers | |
552 | * from an idle cpu. This is good for power-savings. | |
553 | * | |
554 | * We don't do similar optimization for completely idle system, as | |
555 | * selecting an idle cpu will add more delays to the timers than intended | |
556 | * (as that cpu's timer base may not be uptodate wrt jiffies etc). | |
557 | */ | |
558 | int get_nohz_timer_target(void) | |
559 | { | |
560 | int cpu = smp_processor_id(); | |
561 | int i; | |
562 | struct sched_domain *sd; | |
563 | ||
057f3fad | 564 | rcu_read_lock(); |
83cd4fe2 | 565 | for_each_domain(cpu, sd) { |
057f3fad PZ |
566 | for_each_cpu(i, sched_domain_span(sd)) { |
567 | if (!idle_cpu(i)) { | |
568 | cpu = i; | |
569 | goto unlock; | |
570 | } | |
571 | } | |
83cd4fe2 | 572 | } |
057f3fad PZ |
573 | unlock: |
574 | rcu_read_unlock(); | |
83cd4fe2 VP |
575 | return cpu; |
576 | } | |
06d8308c TG |
577 | /* |
578 | * When add_timer_on() enqueues a timer into the timer wheel of an | |
579 | * idle CPU then this timer might expire before the next timer event | |
580 | * which is scheduled to wake up that CPU. In case of a completely | |
581 | * idle system the next event might even be infinite time into the | |
582 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and | |
583 | * leaves the inner idle loop so the newly added timer is taken into | |
584 | * account when the CPU goes back to idle and evaluates the timer | |
585 | * wheel for the next timer event. | |
586 | */ | |
1c20091e | 587 | static void wake_up_idle_cpu(int cpu) |
06d8308c TG |
588 | { |
589 | struct rq *rq = cpu_rq(cpu); | |
590 | ||
591 | if (cpu == smp_processor_id()) | |
592 | return; | |
593 | ||
594 | /* | |
595 | * This is safe, as this function is called with the timer | |
596 | * wheel base lock of (cpu) held. When the CPU is on the way | |
597 | * to idle and has not yet set rq->curr to idle then it will | |
598 | * be serialized on the timer wheel base lock and take the new | |
599 | * timer into account automatically. | |
600 | */ | |
601 | if (rq->curr != rq->idle) | |
602 | return; | |
45bf76df | 603 | |
45bf76df | 604 | /* |
06d8308c TG |
605 | * We can set TIF_RESCHED on the idle task of the other CPU |
606 | * lockless. The worst case is that the other CPU runs the | |
607 | * idle task through an additional NOOP schedule() | |
45bf76df | 608 | */ |
5ed0cec0 | 609 | set_tsk_need_resched(rq->idle); |
45bf76df | 610 | |
06d8308c TG |
611 | /* NEED_RESCHED must be visible before we test polling */ |
612 | smp_mb(); | |
613 | if (!tsk_is_polling(rq->idle)) | |
614 | smp_send_reschedule(cpu); | |
45bf76df IM |
615 | } |
616 | ||
c5bfece2 | 617 | static bool wake_up_full_nohz_cpu(int cpu) |
1c20091e | 618 | { |
c5bfece2 | 619 | if (tick_nohz_full_cpu(cpu)) { |
1c20091e FW |
620 | if (cpu != smp_processor_id() || |
621 | tick_nohz_tick_stopped()) | |
622 | smp_send_reschedule(cpu); | |
623 | return true; | |
624 | } | |
625 | ||
626 | return false; | |
627 | } | |
628 | ||
629 | void wake_up_nohz_cpu(int cpu) | |
630 | { | |
c5bfece2 | 631 | if (!wake_up_full_nohz_cpu(cpu)) |
1c20091e FW |
632 | wake_up_idle_cpu(cpu); |
633 | } | |
634 | ||
ca38062e | 635 | static inline bool got_nohz_idle_kick(void) |
45bf76df | 636 | { |
1c792db7 | 637 | int cpu = smp_processor_id(); |
873b4c65 VG |
638 | |
639 | if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) | |
640 | return false; | |
641 | ||
642 | if (idle_cpu(cpu) && !need_resched()) | |
643 | return true; | |
644 | ||
645 | /* | |
646 | * We can't run Idle Load Balance on this CPU for this time so we | |
647 | * cancel it and clear NOHZ_BALANCE_KICK | |
648 | */ | |
649 | clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); | |
650 | return false; | |
45bf76df IM |
651 | } |
652 | ||
3451d024 | 653 | #else /* CONFIG_NO_HZ_COMMON */ |
45bf76df | 654 | |
ca38062e | 655 | static inline bool got_nohz_idle_kick(void) |
2069dd75 | 656 | { |
ca38062e | 657 | return false; |
2069dd75 PZ |
658 | } |
659 | ||
3451d024 | 660 | #endif /* CONFIG_NO_HZ_COMMON */ |
d842de87 | 661 | |
ce831b38 FW |
662 | #ifdef CONFIG_NO_HZ_FULL |
663 | bool sched_can_stop_tick(void) | |
664 | { | |
665 | struct rq *rq; | |
666 | ||
667 | rq = this_rq(); | |
668 | ||
669 | /* Make sure rq->nr_running update is visible after the IPI */ | |
670 | smp_rmb(); | |
671 | ||
672 | /* More than one running task need preemption */ | |
673 | if (rq->nr_running > 1) | |
674 | return false; | |
675 | ||
676 | return true; | |
677 | } | |
678 | #endif /* CONFIG_NO_HZ_FULL */ | |
d842de87 | 679 | |
029632fb | 680 | void sched_avg_update(struct rq *rq) |
18d95a28 | 681 | { |
e9e9250b PZ |
682 | s64 period = sched_avg_period(); |
683 | ||
78becc27 | 684 | while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { |
0d98bb26 WD |
685 | /* |
686 | * Inline assembly required to prevent the compiler | |
687 | * optimising this loop into a divmod call. | |
688 | * See __iter_div_u64_rem() for another example of this. | |
689 | */ | |
690 | asm("" : "+rm" (rq->age_stamp)); | |
e9e9250b PZ |
691 | rq->age_stamp += period; |
692 | rq->rt_avg /= 2; | |
693 | } | |
18d95a28 PZ |
694 | } |
695 | ||
6d6bc0ad | 696 | #else /* !CONFIG_SMP */ |
029632fb | 697 | void resched_task(struct task_struct *p) |
18d95a28 | 698 | { |
05fa785c | 699 | assert_raw_spin_locked(&task_rq(p)->lock); |
31656519 | 700 | set_tsk_need_resched(p); |
18d95a28 | 701 | } |
6d6bc0ad | 702 | #endif /* CONFIG_SMP */ |
18d95a28 | 703 | |
a790de99 PT |
704 | #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ |
705 | (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) | |
c09595f6 | 706 | /* |
8277434e PT |
707 | * Iterate task_group tree rooted at *from, calling @down when first entering a |
708 | * node and @up when leaving it for the final time. | |
709 | * | |
710 | * Caller must hold rcu_lock or sufficient equivalent. | |
c09595f6 | 711 | */ |
029632fb | 712 | int walk_tg_tree_from(struct task_group *from, |
8277434e | 713 | tg_visitor down, tg_visitor up, void *data) |
c09595f6 PZ |
714 | { |
715 | struct task_group *parent, *child; | |
eb755805 | 716 | int ret; |
c09595f6 | 717 | |
8277434e PT |
718 | parent = from; |
719 | ||
c09595f6 | 720 | down: |
eb755805 PZ |
721 | ret = (*down)(parent, data); |
722 | if (ret) | |
8277434e | 723 | goto out; |
c09595f6 PZ |
724 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
725 | parent = child; | |
726 | goto down; | |
727 | ||
728 | up: | |
729 | continue; | |
730 | } | |
eb755805 | 731 | ret = (*up)(parent, data); |
8277434e PT |
732 | if (ret || parent == from) |
733 | goto out; | |
c09595f6 PZ |
734 | |
735 | child = parent; | |
736 | parent = parent->parent; | |
737 | if (parent) | |
738 | goto up; | |
8277434e | 739 | out: |
eb755805 | 740 | return ret; |
c09595f6 PZ |
741 | } |
742 | ||
029632fb | 743 | int tg_nop(struct task_group *tg, void *data) |
eb755805 | 744 | { |
e2b245f8 | 745 | return 0; |
eb755805 | 746 | } |
18d95a28 PZ |
747 | #endif |
748 | ||
45bf76df IM |
749 | static void set_load_weight(struct task_struct *p) |
750 | { | |
f05998d4 NR |
751 | int prio = p->static_prio - MAX_RT_PRIO; |
752 | struct load_weight *load = &p->se.load; | |
753 | ||
dd41f596 IM |
754 | /* |
755 | * SCHED_IDLE tasks get minimal weight: | |
756 | */ | |
757 | if (p->policy == SCHED_IDLE) { | |
c8b28116 | 758 | load->weight = scale_load(WEIGHT_IDLEPRIO); |
f05998d4 | 759 | load->inv_weight = WMULT_IDLEPRIO; |
dd41f596 IM |
760 | return; |
761 | } | |
71f8bd46 | 762 | |
c8b28116 | 763 | load->weight = scale_load(prio_to_weight[prio]); |
f05998d4 | 764 | load->inv_weight = prio_to_wmult[prio]; |
71f8bd46 IM |
765 | } |
766 | ||
371fd7e7 | 767 | static void enqueue_task(struct rq *rq, struct task_struct *p, int flags) |
2087a1ad | 768 | { |
a64692a3 | 769 | update_rq_clock(rq); |
dd41f596 | 770 | sched_info_queued(p); |
371fd7e7 | 771 | p->sched_class->enqueue_task(rq, p, flags); |
71f8bd46 IM |
772 | } |
773 | ||
371fd7e7 | 774 | static void dequeue_task(struct rq *rq, struct task_struct *p, int flags) |
71f8bd46 | 775 | { |
a64692a3 | 776 | update_rq_clock(rq); |
46ac22ba | 777 | sched_info_dequeued(p); |
371fd7e7 | 778 | p->sched_class->dequeue_task(rq, p, flags); |
71f8bd46 IM |
779 | } |
780 | ||
029632fb | 781 | void activate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
782 | { |
783 | if (task_contributes_to_load(p)) | |
784 | rq->nr_uninterruptible--; | |
785 | ||
371fd7e7 | 786 | enqueue_task(rq, p, flags); |
1e3c88bd PZ |
787 | } |
788 | ||
029632fb | 789 | void deactivate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
790 | { |
791 | if (task_contributes_to_load(p)) | |
792 | rq->nr_uninterruptible++; | |
793 | ||
371fd7e7 | 794 | dequeue_task(rq, p, flags); |
1e3c88bd PZ |
795 | } |
796 | ||
fe44d621 | 797 | static void update_rq_clock_task(struct rq *rq, s64 delta) |
aa483808 | 798 | { |
095c0aa8 GC |
799 | /* |
800 | * In theory, the compile should just see 0 here, and optimize out the call | |
801 | * to sched_rt_avg_update. But I don't trust it... | |
802 | */ | |
803 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) | |
804 | s64 steal = 0, irq_delta = 0; | |
805 | #endif | |
806 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING | |
8e92c201 | 807 | irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; |
fe44d621 PZ |
808 | |
809 | /* | |
810 | * Since irq_time is only updated on {soft,}irq_exit, we might run into | |
811 | * this case when a previous update_rq_clock() happened inside a | |
812 | * {soft,}irq region. | |
813 | * | |
814 | * When this happens, we stop ->clock_task and only update the | |
815 | * prev_irq_time stamp to account for the part that fit, so that a next | |
816 | * update will consume the rest. This ensures ->clock_task is | |
817 | * monotonic. | |
818 | * | |
819 | * It does however cause some slight miss-attribution of {soft,}irq | |
820 | * time, a more accurate solution would be to update the irq_time using | |
821 | * the current rq->clock timestamp, except that would require using | |
822 | * atomic ops. | |
823 | */ | |
824 | if (irq_delta > delta) | |
825 | irq_delta = delta; | |
826 | ||
827 | rq->prev_irq_time += irq_delta; | |
828 | delta -= irq_delta; | |
095c0aa8 GC |
829 | #endif |
830 | #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING | |
c5905afb | 831 | if (static_key_false((¶virt_steal_rq_enabled))) { |
095c0aa8 GC |
832 | u64 st; |
833 | ||
834 | steal = paravirt_steal_clock(cpu_of(rq)); | |
835 | steal -= rq->prev_steal_time_rq; | |
836 | ||
837 | if (unlikely(steal > delta)) | |
838 | steal = delta; | |
839 | ||
840 | st = steal_ticks(steal); | |
841 | steal = st * TICK_NSEC; | |
842 | ||
843 | rq->prev_steal_time_rq += steal; | |
844 | ||
845 | delta -= steal; | |
846 | } | |
847 | #endif | |
848 | ||
fe44d621 PZ |
849 | rq->clock_task += delta; |
850 | ||
095c0aa8 GC |
851 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) |
852 | if ((irq_delta + steal) && sched_feat(NONTASK_POWER)) | |
853 | sched_rt_avg_update(rq, irq_delta + steal); | |
854 | #endif | |
aa483808 VP |
855 | } |
856 | ||
34f971f6 PZ |
857 | void sched_set_stop_task(int cpu, struct task_struct *stop) |
858 | { | |
859 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
860 | struct task_struct *old_stop = cpu_rq(cpu)->stop; | |
861 | ||
862 | if (stop) { | |
863 | /* | |
864 | * Make it appear like a SCHED_FIFO task, its something | |
865 | * userspace knows about and won't get confused about. | |
866 | * | |
867 | * Also, it will make PI more or less work without too | |
868 | * much confusion -- but then, stop work should not | |
869 | * rely on PI working anyway. | |
870 | */ | |
871 | sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); | |
872 | ||
873 | stop->sched_class = &stop_sched_class; | |
874 | } | |
875 | ||
876 | cpu_rq(cpu)->stop = stop; | |
877 | ||
878 | if (old_stop) { | |
879 | /* | |
880 | * Reset it back to a normal scheduling class so that | |
881 | * it can die in pieces. | |
882 | */ | |
883 | old_stop->sched_class = &rt_sched_class; | |
884 | } | |
885 | } | |
886 | ||
14531189 | 887 | /* |
dd41f596 | 888 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 889 | */ |
14531189 IM |
890 | static inline int __normal_prio(struct task_struct *p) |
891 | { | |
dd41f596 | 892 | return p->static_prio; |
14531189 IM |
893 | } |
894 | ||
b29739f9 IM |
895 | /* |
896 | * Calculate the expected normal priority: i.e. priority | |
897 | * without taking RT-inheritance into account. Might be | |
898 | * boosted by interactivity modifiers. Changes upon fork, | |
899 | * setprio syscalls, and whenever the interactivity | |
900 | * estimator recalculates. | |
901 | */ | |
36c8b586 | 902 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
903 | { |
904 | int prio; | |
905 | ||
e05606d3 | 906 | if (task_has_rt_policy(p)) |
b29739f9 IM |
907 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
908 | else | |
909 | prio = __normal_prio(p); | |
910 | return prio; | |
911 | } | |
912 | ||
913 | /* | |
914 | * Calculate the current priority, i.e. the priority | |
915 | * taken into account by the scheduler. This value might | |
916 | * be boosted by RT tasks, or might be boosted by | |
917 | * interactivity modifiers. Will be RT if the task got | |
918 | * RT-boosted. If not then it returns p->normal_prio. | |
919 | */ | |
36c8b586 | 920 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
921 | { |
922 | p->normal_prio = normal_prio(p); | |
923 | /* | |
924 | * If we are RT tasks or we were boosted to RT priority, | |
925 | * keep the priority unchanged. Otherwise, update priority | |
926 | * to the normal priority: | |
927 | */ | |
928 | if (!rt_prio(p->prio)) | |
929 | return p->normal_prio; | |
930 | return p->prio; | |
931 | } | |
932 | ||
1da177e4 LT |
933 | /** |
934 | * task_curr - is this task currently executing on a CPU? | |
935 | * @p: the task in question. | |
e69f6186 YB |
936 | * |
937 | * Return: 1 if the task is currently executing. 0 otherwise. | |
1da177e4 | 938 | */ |
36c8b586 | 939 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
940 | { |
941 | return cpu_curr(task_cpu(p)) == p; | |
942 | } | |
943 | ||
cb469845 SR |
944 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
945 | const struct sched_class *prev_class, | |
da7a735e | 946 | int oldprio) |
cb469845 SR |
947 | { |
948 | if (prev_class != p->sched_class) { | |
949 | if (prev_class->switched_from) | |
da7a735e PZ |
950 | prev_class->switched_from(rq, p); |
951 | p->sched_class->switched_to(rq, p); | |
952 | } else if (oldprio != p->prio) | |
953 | p->sched_class->prio_changed(rq, p, oldprio); | |
cb469845 SR |
954 | } |
955 | ||
029632fb | 956 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
1e5a7405 PZ |
957 | { |
958 | const struct sched_class *class; | |
959 | ||
960 | if (p->sched_class == rq->curr->sched_class) { | |
961 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); | |
962 | } else { | |
963 | for_each_class(class) { | |
964 | if (class == rq->curr->sched_class) | |
965 | break; | |
966 | if (class == p->sched_class) { | |
967 | resched_task(rq->curr); | |
968 | break; | |
969 | } | |
970 | } | |
971 | } | |
972 | ||
973 | /* | |
974 | * A queue event has occurred, and we're going to schedule. In | |
975 | * this case, we can save a useless back to back clock update. | |
976 | */ | |
fd2f4419 | 977 | if (rq->curr->on_rq && test_tsk_need_resched(rq->curr)) |
1e5a7405 PZ |
978 | rq->skip_clock_update = 1; |
979 | } | |
980 | ||
1da177e4 | 981 | #ifdef CONFIG_SMP |
dd41f596 | 982 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 983 | { |
e2912009 PZ |
984 | #ifdef CONFIG_SCHED_DEBUG |
985 | /* | |
986 | * We should never call set_task_cpu() on a blocked task, | |
987 | * ttwu() will sort out the placement. | |
988 | */ | |
077614ee PZ |
989 | WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && |
990 | !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); | |
0122ec5b PZ |
991 | |
992 | #ifdef CONFIG_LOCKDEP | |
6c6c54e1 PZ |
993 | /* |
994 | * The caller should hold either p->pi_lock or rq->lock, when changing | |
995 | * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. | |
996 | * | |
997 | * sched_move_task() holds both and thus holding either pins the cgroup, | |
8323f26c | 998 | * see task_group(). |
6c6c54e1 PZ |
999 | * |
1000 | * Furthermore, all task_rq users should acquire both locks, see | |
1001 | * task_rq_lock(). | |
1002 | */ | |
0122ec5b PZ |
1003 | WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || |
1004 | lockdep_is_held(&task_rq(p)->lock))); | |
1005 | #endif | |
e2912009 PZ |
1006 | #endif |
1007 | ||
de1d7286 | 1008 | trace_sched_migrate_task(p, new_cpu); |
cbc34ed1 | 1009 | |
0c69774e | 1010 | if (task_cpu(p) != new_cpu) { |
0a74bef8 PT |
1011 | if (p->sched_class->migrate_task_rq) |
1012 | p->sched_class->migrate_task_rq(p, new_cpu); | |
0c69774e | 1013 | p->se.nr_migrations++; |
a8b0ca17 | 1014 | perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0); |
0c69774e | 1015 | } |
dd41f596 IM |
1016 | |
1017 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1018 | } |
1019 | ||
969c7921 | 1020 | struct migration_arg { |
36c8b586 | 1021 | struct task_struct *task; |
1da177e4 | 1022 | int dest_cpu; |
70b97a7f | 1023 | }; |
1da177e4 | 1024 | |
969c7921 TH |
1025 | static int migration_cpu_stop(void *data); |
1026 | ||
1da177e4 LT |
1027 | /* |
1028 | * wait_task_inactive - wait for a thread to unschedule. | |
1029 | * | |
85ba2d86 RM |
1030 | * If @match_state is nonzero, it's the @p->state value just checked and |
1031 | * not expected to change. If it changes, i.e. @p might have woken up, | |
1032 | * then return zero. When we succeed in waiting for @p to be off its CPU, | |
1033 | * we return a positive number (its total switch count). If a second call | |
1034 | * a short while later returns the same number, the caller can be sure that | |
1035 | * @p has remained unscheduled the whole time. | |
1036 | * | |
1da177e4 LT |
1037 | * The caller must ensure that the task *will* unschedule sometime soon, |
1038 | * else this function might spin for a *long* time. This function can't | |
1039 | * be called with interrupts off, or it may introduce deadlock with | |
1040 | * smp_call_function() if an IPI is sent by the same process we are | |
1041 | * waiting to become inactive. | |
1042 | */ | |
85ba2d86 | 1043 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
1da177e4 LT |
1044 | { |
1045 | unsigned long flags; | |
dd41f596 | 1046 | int running, on_rq; |
85ba2d86 | 1047 | unsigned long ncsw; |
70b97a7f | 1048 | struct rq *rq; |
1da177e4 | 1049 | |
3a5c359a AK |
1050 | for (;;) { |
1051 | /* | |
1052 | * We do the initial early heuristics without holding | |
1053 | * any task-queue locks at all. We'll only try to get | |
1054 | * the runqueue lock when things look like they will | |
1055 | * work out! | |
1056 | */ | |
1057 | rq = task_rq(p); | |
fa490cfd | 1058 | |
3a5c359a AK |
1059 | /* |
1060 | * If the task is actively running on another CPU | |
1061 | * still, just relax and busy-wait without holding | |
1062 | * any locks. | |
1063 | * | |
1064 | * NOTE! Since we don't hold any locks, it's not | |
1065 | * even sure that "rq" stays as the right runqueue! | |
1066 | * But we don't care, since "task_running()" will | |
1067 | * return false if the runqueue has changed and p | |
1068 | * is actually now running somewhere else! | |
1069 | */ | |
85ba2d86 RM |
1070 | while (task_running(rq, p)) { |
1071 | if (match_state && unlikely(p->state != match_state)) | |
1072 | return 0; | |
3a5c359a | 1073 | cpu_relax(); |
85ba2d86 | 1074 | } |
fa490cfd | 1075 | |
3a5c359a AK |
1076 | /* |
1077 | * Ok, time to look more closely! We need the rq | |
1078 | * lock now, to be *sure*. If we're wrong, we'll | |
1079 | * just go back and repeat. | |
1080 | */ | |
1081 | rq = task_rq_lock(p, &flags); | |
27a9da65 | 1082 | trace_sched_wait_task(p); |
3a5c359a | 1083 | running = task_running(rq, p); |
fd2f4419 | 1084 | on_rq = p->on_rq; |
85ba2d86 | 1085 | ncsw = 0; |
f31e11d8 | 1086 | if (!match_state || p->state == match_state) |
93dcf55f | 1087 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
0122ec5b | 1088 | task_rq_unlock(rq, p, &flags); |
fa490cfd | 1089 | |
85ba2d86 RM |
1090 | /* |
1091 | * If it changed from the expected state, bail out now. | |
1092 | */ | |
1093 | if (unlikely(!ncsw)) | |
1094 | break; | |
1095 | ||
3a5c359a AK |
1096 | /* |
1097 | * Was it really running after all now that we | |
1098 | * checked with the proper locks actually held? | |
1099 | * | |
1100 | * Oops. Go back and try again.. | |
1101 | */ | |
1102 | if (unlikely(running)) { | |
1103 | cpu_relax(); | |
1104 | continue; | |
1105 | } | |
fa490cfd | 1106 | |
3a5c359a AK |
1107 | /* |
1108 | * It's not enough that it's not actively running, | |
1109 | * it must be off the runqueue _entirely_, and not | |
1110 | * preempted! | |
1111 | * | |
80dd99b3 | 1112 | * So if it was still runnable (but just not actively |
3a5c359a AK |
1113 | * running right now), it's preempted, and we should |
1114 | * yield - it could be a while. | |
1115 | */ | |
1116 | if (unlikely(on_rq)) { | |
8eb90c30 TG |
1117 | ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); |
1118 | ||
1119 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1120 | schedule_hrtimeout(&to, HRTIMER_MODE_REL); | |
3a5c359a AK |
1121 | continue; |
1122 | } | |
fa490cfd | 1123 | |
3a5c359a AK |
1124 | /* |
1125 | * Ahh, all good. It wasn't running, and it wasn't | |
1126 | * runnable, which means that it will never become | |
1127 | * running in the future either. We're all done! | |
1128 | */ | |
1129 | break; | |
1130 | } | |
85ba2d86 RM |
1131 | |
1132 | return ncsw; | |
1da177e4 LT |
1133 | } |
1134 | ||
1135 | /*** | |
1136 | * kick_process - kick a running thread to enter/exit the kernel | |
1137 | * @p: the to-be-kicked thread | |
1138 | * | |
1139 | * Cause a process which is running on another CPU to enter | |
1140 | * kernel-mode, without any delay. (to get signals handled.) | |
1141 | * | |
25985edc | 1142 | * NOTE: this function doesn't have to take the runqueue lock, |
1da177e4 LT |
1143 | * because all it wants to ensure is that the remote task enters |
1144 | * the kernel. If the IPI races and the task has been migrated | |
1145 | * to another CPU then no harm is done and the purpose has been | |
1146 | * achieved as well. | |
1147 | */ | |
36c8b586 | 1148 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1149 | { |
1150 | int cpu; | |
1151 | ||
1152 | preempt_disable(); | |
1153 | cpu = task_cpu(p); | |
1154 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1155 | smp_send_reschedule(cpu); | |
1156 | preempt_enable(); | |
1157 | } | |
b43e3521 | 1158 | EXPORT_SYMBOL_GPL(kick_process); |
476d139c | 1159 | #endif /* CONFIG_SMP */ |
1da177e4 | 1160 | |
970b13ba | 1161 | #ifdef CONFIG_SMP |
30da688e | 1162 | /* |
013fdb80 | 1163 | * ->cpus_allowed is protected by both rq->lock and p->pi_lock |
30da688e | 1164 | */ |
5da9a0fb PZ |
1165 | static int select_fallback_rq(int cpu, struct task_struct *p) |
1166 | { | |
aa00d89c TC |
1167 | int nid = cpu_to_node(cpu); |
1168 | const struct cpumask *nodemask = NULL; | |
2baab4e9 PZ |
1169 | enum { cpuset, possible, fail } state = cpuset; |
1170 | int dest_cpu; | |
5da9a0fb | 1171 | |
aa00d89c TC |
1172 | /* |
1173 | * If the node that the cpu is on has been offlined, cpu_to_node() | |
1174 | * will return -1. There is no cpu on the node, and we should | |
1175 | * select the cpu on the other node. | |
1176 | */ | |
1177 | if (nid != -1) { | |
1178 | nodemask = cpumask_of_node(nid); | |
1179 | ||
1180 | /* Look for allowed, online CPU in same node. */ | |
1181 | for_each_cpu(dest_cpu, nodemask) { | |
1182 | if (!cpu_online(dest_cpu)) | |
1183 | continue; | |
1184 | if (!cpu_active(dest_cpu)) | |
1185 | continue; | |
1186 | if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) | |
1187 | return dest_cpu; | |
1188 | } | |
2baab4e9 | 1189 | } |
5da9a0fb | 1190 | |
2baab4e9 PZ |
1191 | for (;;) { |
1192 | /* Any allowed, online CPU? */ | |
e3831edd | 1193 | for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { |
2baab4e9 PZ |
1194 | if (!cpu_online(dest_cpu)) |
1195 | continue; | |
1196 | if (!cpu_active(dest_cpu)) | |
1197 | continue; | |
1198 | goto out; | |
1199 | } | |
5da9a0fb | 1200 | |
2baab4e9 PZ |
1201 | switch (state) { |
1202 | case cpuset: | |
1203 | /* No more Mr. Nice Guy. */ | |
1204 | cpuset_cpus_allowed_fallback(p); | |
1205 | state = possible; | |
1206 | break; | |
1207 | ||
1208 | case possible: | |
1209 | do_set_cpus_allowed(p, cpu_possible_mask); | |
1210 | state = fail; | |
1211 | break; | |
1212 | ||
1213 | case fail: | |
1214 | BUG(); | |
1215 | break; | |
1216 | } | |
1217 | } | |
1218 | ||
1219 | out: | |
1220 | if (state != cpuset) { | |
1221 | /* | |
1222 | * Don't tell them about moving exiting tasks or | |
1223 | * kernel threads (both mm NULL), since they never | |
1224 | * leave kernel. | |
1225 | */ | |
1226 | if (p->mm && printk_ratelimit()) { | |
1227 | printk_sched("process %d (%s) no longer affine to cpu%d\n", | |
1228 | task_pid_nr(p), p->comm, cpu); | |
1229 | } | |
5da9a0fb PZ |
1230 | } |
1231 | ||
1232 | return dest_cpu; | |
1233 | } | |
1234 | ||
e2912009 | 1235 | /* |
013fdb80 | 1236 | * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. |
e2912009 | 1237 | */ |
970b13ba | 1238 | static inline |
7608dec2 | 1239 | int select_task_rq(struct task_struct *p, int sd_flags, int wake_flags) |
970b13ba | 1240 | { |
7608dec2 | 1241 | int cpu = p->sched_class->select_task_rq(p, sd_flags, wake_flags); |
e2912009 PZ |
1242 | |
1243 | /* | |
1244 | * In order not to call set_task_cpu() on a blocking task we need | |
1245 | * to rely on ttwu() to place the task on a valid ->cpus_allowed | |
1246 | * cpu. | |
1247 | * | |
1248 | * Since this is common to all placement strategies, this lives here. | |
1249 | * | |
1250 | * [ this allows ->select_task() to simply return task_cpu(p) and | |
1251 | * not worry about this generic constraint ] | |
1252 | */ | |
fa17b507 | 1253 | if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || |
70f11205 | 1254 | !cpu_online(cpu))) |
5da9a0fb | 1255 | cpu = select_fallback_rq(task_cpu(p), p); |
e2912009 PZ |
1256 | |
1257 | return cpu; | |
970b13ba | 1258 | } |
09a40af5 MG |
1259 | |
1260 | static void update_avg(u64 *avg, u64 sample) | |
1261 | { | |
1262 | s64 diff = sample - *avg; | |
1263 | *avg += diff >> 3; | |
1264 | } | |
970b13ba PZ |
1265 | #endif |
1266 | ||
d7c01d27 | 1267 | static void |
b84cb5df | 1268 | ttwu_stat(struct task_struct *p, int cpu, int wake_flags) |
9ed3811a | 1269 | { |
d7c01d27 | 1270 | #ifdef CONFIG_SCHEDSTATS |
b84cb5df PZ |
1271 | struct rq *rq = this_rq(); |
1272 | ||
d7c01d27 PZ |
1273 | #ifdef CONFIG_SMP |
1274 | int this_cpu = smp_processor_id(); | |
1275 | ||
1276 | if (cpu == this_cpu) { | |
1277 | schedstat_inc(rq, ttwu_local); | |
1278 | schedstat_inc(p, se.statistics.nr_wakeups_local); | |
1279 | } else { | |
1280 | struct sched_domain *sd; | |
1281 | ||
1282 | schedstat_inc(p, se.statistics.nr_wakeups_remote); | |
057f3fad | 1283 | rcu_read_lock(); |
d7c01d27 PZ |
1284 | for_each_domain(this_cpu, sd) { |
1285 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { | |
1286 | schedstat_inc(sd, ttwu_wake_remote); | |
1287 | break; | |
1288 | } | |
1289 | } | |
057f3fad | 1290 | rcu_read_unlock(); |
d7c01d27 | 1291 | } |
f339b9dc PZ |
1292 | |
1293 | if (wake_flags & WF_MIGRATED) | |
1294 | schedstat_inc(p, se.statistics.nr_wakeups_migrate); | |
1295 | ||
d7c01d27 PZ |
1296 | #endif /* CONFIG_SMP */ |
1297 | ||
1298 | schedstat_inc(rq, ttwu_count); | |
9ed3811a | 1299 | schedstat_inc(p, se.statistics.nr_wakeups); |
d7c01d27 PZ |
1300 | |
1301 | if (wake_flags & WF_SYNC) | |
9ed3811a | 1302 | schedstat_inc(p, se.statistics.nr_wakeups_sync); |
d7c01d27 | 1303 | |
d7c01d27 PZ |
1304 | #endif /* CONFIG_SCHEDSTATS */ |
1305 | } | |
1306 | ||
1307 | static void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) | |
1308 | { | |
9ed3811a | 1309 | activate_task(rq, p, en_flags); |
fd2f4419 | 1310 | p->on_rq = 1; |
c2f7115e PZ |
1311 | |
1312 | /* if a worker is waking up, notify workqueue */ | |
1313 | if (p->flags & PF_WQ_WORKER) | |
1314 | wq_worker_waking_up(p, cpu_of(rq)); | |
9ed3811a TH |
1315 | } |
1316 | ||
23f41eeb PZ |
1317 | /* |
1318 | * Mark the task runnable and perform wakeup-preemption. | |
1319 | */ | |
89363381 | 1320 | static void |
23f41eeb | 1321 | ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
9ed3811a | 1322 | { |
9ed3811a | 1323 | check_preempt_curr(rq, p, wake_flags); |
a8d7ad52 | 1324 | trace_sched_wakeup(p, true); |
9ed3811a TH |
1325 | |
1326 | p->state = TASK_RUNNING; | |
1327 | #ifdef CONFIG_SMP | |
1328 | if (p->sched_class->task_woken) | |
1329 | p->sched_class->task_woken(rq, p); | |
1330 | ||
e69c6341 | 1331 | if (rq->idle_stamp) { |
78becc27 | 1332 | u64 delta = rq_clock(rq) - rq->idle_stamp; |
9ed3811a TH |
1333 | u64 max = 2*sysctl_sched_migration_cost; |
1334 | ||
1335 | if (delta > max) | |
1336 | rq->avg_idle = max; | |
1337 | else | |
1338 | update_avg(&rq->avg_idle, delta); | |
1339 | rq->idle_stamp = 0; | |
1340 | } | |
1341 | #endif | |
1342 | } | |
1343 | ||
c05fbafb PZ |
1344 | static void |
1345 | ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) | |
1346 | { | |
1347 | #ifdef CONFIG_SMP | |
1348 | if (p->sched_contributes_to_load) | |
1349 | rq->nr_uninterruptible--; | |
1350 | #endif | |
1351 | ||
1352 | ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); | |
1353 | ttwu_do_wakeup(rq, p, wake_flags); | |
1354 | } | |
1355 | ||
1356 | /* | |
1357 | * Called in case the task @p isn't fully descheduled from its runqueue, | |
1358 | * in this case we must do a remote wakeup. Its a 'light' wakeup though, | |
1359 | * since all we need to do is flip p->state to TASK_RUNNING, since | |
1360 | * the task is still ->on_rq. | |
1361 | */ | |
1362 | static int ttwu_remote(struct task_struct *p, int wake_flags) | |
1363 | { | |
1364 | struct rq *rq; | |
1365 | int ret = 0; | |
1366 | ||
1367 | rq = __task_rq_lock(p); | |
1368 | if (p->on_rq) { | |
1ad4ec0d FW |
1369 | /* check_preempt_curr() may use rq clock */ |
1370 | update_rq_clock(rq); | |
c05fbafb PZ |
1371 | ttwu_do_wakeup(rq, p, wake_flags); |
1372 | ret = 1; | |
1373 | } | |
1374 | __task_rq_unlock(rq); | |
1375 | ||
1376 | return ret; | |
1377 | } | |
1378 | ||
317f3941 | 1379 | #ifdef CONFIG_SMP |
fa14ff4a | 1380 | static void sched_ttwu_pending(void) |
317f3941 PZ |
1381 | { |
1382 | struct rq *rq = this_rq(); | |
fa14ff4a PZ |
1383 | struct llist_node *llist = llist_del_all(&rq->wake_list); |
1384 | struct task_struct *p; | |
317f3941 PZ |
1385 | |
1386 | raw_spin_lock(&rq->lock); | |
1387 | ||
fa14ff4a PZ |
1388 | while (llist) { |
1389 | p = llist_entry(llist, struct task_struct, wake_entry); | |
1390 | llist = llist_next(llist); | |
317f3941 PZ |
1391 | ttwu_do_activate(rq, p, 0); |
1392 | } | |
1393 | ||
1394 | raw_spin_unlock(&rq->lock); | |
1395 | } | |
1396 | ||
1397 | void scheduler_ipi(void) | |
1398 | { | |
873b4c65 VG |
1399 | if (llist_empty(&this_rq()->wake_list) |
1400 | && !tick_nohz_full_cpu(smp_processor_id()) | |
1401 | && !got_nohz_idle_kick()) | |
c5d753a5 PZ |
1402 | return; |
1403 | ||
1404 | /* | |
1405 | * Not all reschedule IPI handlers call irq_enter/irq_exit, since | |
1406 | * traditionally all their work was done from the interrupt return | |
1407 | * path. Now that we actually do some work, we need to make sure | |
1408 | * we do call them. | |
1409 | * | |
1410 | * Some archs already do call them, luckily irq_enter/exit nest | |
1411 | * properly. | |
1412 | * | |
1413 | * Arguably we should visit all archs and update all handlers, | |
1414 | * however a fair share of IPIs are still resched only so this would | |
1415 | * somewhat pessimize the simple resched case. | |
1416 | */ | |
1417 | irq_enter(); | |
ff442c51 | 1418 | tick_nohz_full_check(); |
fa14ff4a | 1419 | sched_ttwu_pending(); |
ca38062e SS |
1420 | |
1421 | /* | |
1422 | * Check if someone kicked us for doing the nohz idle load balance. | |
1423 | */ | |
873b4c65 | 1424 | if (unlikely(got_nohz_idle_kick())) { |
6eb57e0d | 1425 | this_rq()->idle_balance = 1; |
ca38062e | 1426 | raise_softirq_irqoff(SCHED_SOFTIRQ); |
6eb57e0d | 1427 | } |
c5d753a5 | 1428 | irq_exit(); |
317f3941 PZ |
1429 | } |
1430 | ||
1431 | static void ttwu_queue_remote(struct task_struct *p, int cpu) | |
1432 | { | |
fa14ff4a | 1433 | if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) |
317f3941 PZ |
1434 | smp_send_reschedule(cpu); |
1435 | } | |
d6aa8f85 | 1436 | |
39be3501 | 1437 | bool cpus_share_cache(int this_cpu, int that_cpu) |
518cd623 PZ |
1438 | { |
1439 | return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); | |
1440 | } | |
d6aa8f85 | 1441 | #endif /* CONFIG_SMP */ |
317f3941 | 1442 | |
c05fbafb PZ |
1443 | static void ttwu_queue(struct task_struct *p, int cpu) |
1444 | { | |
1445 | struct rq *rq = cpu_rq(cpu); | |
1446 | ||
17d9f311 | 1447 | #if defined(CONFIG_SMP) |
39be3501 | 1448 | if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { |
f01114cb | 1449 | sched_clock_cpu(cpu); /* sync clocks x-cpu */ |
317f3941 PZ |
1450 | ttwu_queue_remote(p, cpu); |
1451 | return; | |
1452 | } | |
1453 | #endif | |
1454 | ||
c05fbafb PZ |
1455 | raw_spin_lock(&rq->lock); |
1456 | ttwu_do_activate(rq, p, 0); | |
1457 | raw_spin_unlock(&rq->lock); | |
9ed3811a TH |
1458 | } |
1459 | ||
1460 | /** | |
1da177e4 | 1461 | * try_to_wake_up - wake up a thread |
9ed3811a | 1462 | * @p: the thread to be awakened |
1da177e4 | 1463 | * @state: the mask of task states that can be woken |
9ed3811a | 1464 | * @wake_flags: wake modifier flags (WF_*) |
1da177e4 LT |
1465 | * |
1466 | * Put it on the run-queue if it's not already there. The "current" | |
1467 | * thread is always on the run-queue (except when the actual | |
1468 | * re-schedule is in progress), and as such you're allowed to do | |
1469 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1470 | * runnable without the overhead of this. | |
1471 | * | |
e69f6186 | 1472 | * Return: %true if @p was woken up, %false if it was already running. |
9ed3811a | 1473 | * or @state didn't match @p's state. |
1da177e4 | 1474 | */ |
e4a52bcb PZ |
1475 | static int |
1476 | try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) | |
1da177e4 | 1477 | { |
1da177e4 | 1478 | unsigned long flags; |
c05fbafb | 1479 | int cpu, success = 0; |
2398f2c6 | 1480 | |
e0acd0a6 ON |
1481 | /* |
1482 | * If we are going to wake up a thread waiting for CONDITION we | |
1483 | * need to ensure that CONDITION=1 done by the caller can not be | |
1484 | * reordered with p->state check below. This pairs with mb() in | |
1485 | * set_current_state() the waiting thread does. | |
1486 | */ | |
1487 | smp_mb__before_spinlock(); | |
013fdb80 | 1488 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
e9c84311 | 1489 | if (!(p->state & state)) |
1da177e4 LT |
1490 | goto out; |
1491 | ||
c05fbafb | 1492 | success = 1; /* we're going to change ->state */ |
1da177e4 | 1493 | cpu = task_cpu(p); |
1da177e4 | 1494 | |
c05fbafb PZ |
1495 | if (p->on_rq && ttwu_remote(p, wake_flags)) |
1496 | goto stat; | |
1da177e4 | 1497 | |
1da177e4 | 1498 | #ifdef CONFIG_SMP |
e9c84311 | 1499 | /* |
c05fbafb PZ |
1500 | * If the owning (remote) cpu is still in the middle of schedule() with |
1501 | * this task as prev, wait until its done referencing the task. | |
e9c84311 | 1502 | */ |
f3e94786 | 1503 | while (p->on_cpu) |
e4a52bcb | 1504 | cpu_relax(); |
0970d299 | 1505 | /* |
e4a52bcb | 1506 | * Pairs with the smp_wmb() in finish_lock_switch(). |
0970d299 | 1507 | */ |
e4a52bcb | 1508 | smp_rmb(); |
1da177e4 | 1509 | |
a8e4f2ea | 1510 | p->sched_contributes_to_load = !!task_contributes_to_load(p); |
e9c84311 | 1511 | p->state = TASK_WAKING; |
e7693a36 | 1512 | |
e4a52bcb | 1513 | if (p->sched_class->task_waking) |
74f8e4b2 | 1514 | p->sched_class->task_waking(p); |
efbbd05a | 1515 | |
7608dec2 | 1516 | cpu = select_task_rq(p, SD_BALANCE_WAKE, wake_flags); |
f339b9dc PZ |
1517 | if (task_cpu(p) != cpu) { |
1518 | wake_flags |= WF_MIGRATED; | |
e4a52bcb | 1519 | set_task_cpu(p, cpu); |
f339b9dc | 1520 | } |
1da177e4 | 1521 | #endif /* CONFIG_SMP */ |
1da177e4 | 1522 | |
c05fbafb PZ |
1523 | ttwu_queue(p, cpu); |
1524 | stat: | |
b84cb5df | 1525 | ttwu_stat(p, cpu, wake_flags); |
1da177e4 | 1526 | out: |
013fdb80 | 1527 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
1528 | |
1529 | return success; | |
1530 | } | |
1531 | ||
21aa9af0 TH |
1532 | /** |
1533 | * try_to_wake_up_local - try to wake up a local task with rq lock held | |
1534 | * @p: the thread to be awakened | |
1535 | * | |
2acca55e | 1536 | * Put @p on the run-queue if it's not already there. The caller must |
21aa9af0 | 1537 | * ensure that this_rq() is locked, @p is bound to this_rq() and not |
2acca55e | 1538 | * the current task. |
21aa9af0 TH |
1539 | */ |
1540 | static void try_to_wake_up_local(struct task_struct *p) | |
1541 | { | |
1542 | struct rq *rq = task_rq(p); | |
21aa9af0 | 1543 | |
383efcd0 TH |
1544 | if (WARN_ON_ONCE(rq != this_rq()) || |
1545 | WARN_ON_ONCE(p == current)) | |
1546 | return; | |
1547 | ||
21aa9af0 TH |
1548 | lockdep_assert_held(&rq->lock); |
1549 | ||
2acca55e PZ |
1550 | if (!raw_spin_trylock(&p->pi_lock)) { |
1551 | raw_spin_unlock(&rq->lock); | |
1552 | raw_spin_lock(&p->pi_lock); | |
1553 | raw_spin_lock(&rq->lock); | |
1554 | } | |
1555 | ||
21aa9af0 | 1556 | if (!(p->state & TASK_NORMAL)) |
2acca55e | 1557 | goto out; |
21aa9af0 | 1558 | |
fd2f4419 | 1559 | if (!p->on_rq) |
d7c01d27 PZ |
1560 | ttwu_activate(rq, p, ENQUEUE_WAKEUP); |
1561 | ||
23f41eeb | 1562 | ttwu_do_wakeup(rq, p, 0); |
b84cb5df | 1563 | ttwu_stat(p, smp_processor_id(), 0); |
2acca55e PZ |
1564 | out: |
1565 | raw_spin_unlock(&p->pi_lock); | |
21aa9af0 TH |
1566 | } |
1567 | ||
50fa610a DH |
1568 | /** |
1569 | * wake_up_process - Wake up a specific process | |
1570 | * @p: The process to be woken up. | |
1571 | * | |
1572 | * Attempt to wake up the nominated process and move it to the set of runnable | |
e69f6186 YB |
1573 | * processes. |
1574 | * | |
1575 | * Return: 1 if the process was woken up, 0 if it was already running. | |
50fa610a DH |
1576 | * |
1577 | * It may be assumed that this function implies a write memory barrier before | |
1578 | * changing the task state if and only if any tasks are woken up. | |
1579 | */ | |
7ad5b3a5 | 1580 | int wake_up_process(struct task_struct *p) |
1da177e4 | 1581 | { |
9067ac85 ON |
1582 | WARN_ON(task_is_stopped_or_traced(p)); |
1583 | return try_to_wake_up(p, TASK_NORMAL, 0); | |
1da177e4 | 1584 | } |
1da177e4 LT |
1585 | EXPORT_SYMBOL(wake_up_process); |
1586 | ||
7ad5b3a5 | 1587 | int wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
1588 | { |
1589 | return try_to_wake_up(p, state, 0); | |
1590 | } | |
1591 | ||
1da177e4 LT |
1592 | /* |
1593 | * Perform scheduler related setup for a newly forked process p. | |
1594 | * p is forked by current. | |
dd41f596 IM |
1595 | * |
1596 | * __sched_fork() is basic setup used by init_idle() too: | |
1597 | */ | |
1598 | static void __sched_fork(struct task_struct *p) | |
1599 | { | |
fd2f4419 PZ |
1600 | p->on_rq = 0; |
1601 | ||
1602 | p->se.on_rq = 0; | |
dd41f596 IM |
1603 | p->se.exec_start = 0; |
1604 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 1605 | p->se.prev_sum_exec_runtime = 0; |
6c594c21 | 1606 | p->se.nr_migrations = 0; |
da7a735e | 1607 | p->se.vruntime = 0; |
fd2f4419 | 1608 | INIT_LIST_HEAD(&p->se.group_node); |
6cfb0d5d IM |
1609 | |
1610 | #ifdef CONFIG_SCHEDSTATS | |
41acab88 | 1611 | memset(&p->se.statistics, 0, sizeof(p->se.statistics)); |
6cfb0d5d | 1612 | #endif |
476d139c | 1613 | |
fa717060 | 1614 | INIT_LIST_HEAD(&p->rt.run_list); |
476d139c | 1615 | |
e107be36 AK |
1616 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1617 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
1618 | #endif | |
cbee9f88 PZ |
1619 | |
1620 | #ifdef CONFIG_NUMA_BALANCING | |
1621 | if (p->mm && atomic_read(&p->mm->mm_users) == 1) { | |
1622 | p->mm->numa_next_scan = jiffies; | |
b8593bfd | 1623 | p->mm->numa_next_reset = jiffies; |
cbee9f88 PZ |
1624 | p->mm->numa_scan_seq = 0; |
1625 | } | |
1626 | ||
1627 | p->node_stamp = 0ULL; | |
1628 | p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; | |
1629 | p->numa_migrate_seq = p->mm ? p->mm->numa_scan_seq - 1 : 0; | |
4b96a29b | 1630 | p->numa_scan_period = sysctl_numa_balancing_scan_delay; |
cbee9f88 PZ |
1631 | p->numa_work.next = &p->numa_work; |
1632 | #endif /* CONFIG_NUMA_BALANCING */ | |
dd41f596 IM |
1633 | } |
1634 | ||
1a687c2e | 1635 | #ifdef CONFIG_NUMA_BALANCING |
3105b86a | 1636 | #ifdef CONFIG_SCHED_DEBUG |
1a687c2e MG |
1637 | void set_numabalancing_state(bool enabled) |
1638 | { | |
1639 | if (enabled) | |
1640 | sched_feat_set("NUMA"); | |
1641 | else | |
1642 | sched_feat_set("NO_NUMA"); | |
1643 | } | |
3105b86a MG |
1644 | #else |
1645 | __read_mostly bool numabalancing_enabled; | |
1646 | ||
1647 | void set_numabalancing_state(bool enabled) | |
1648 | { | |
1649 | numabalancing_enabled = enabled; | |
dd41f596 | 1650 | } |
3105b86a | 1651 | #endif /* CONFIG_SCHED_DEBUG */ |
1a687c2e | 1652 | #endif /* CONFIG_NUMA_BALANCING */ |
dd41f596 IM |
1653 | |
1654 | /* | |
1655 | * fork()/clone()-time setup: | |
1656 | */ | |
3e51e3ed | 1657 | void sched_fork(struct task_struct *p) |
dd41f596 | 1658 | { |
0122ec5b | 1659 | unsigned long flags; |
dd41f596 IM |
1660 | int cpu = get_cpu(); |
1661 | ||
1662 | __sched_fork(p); | |
06b83b5f | 1663 | /* |
0017d735 | 1664 | * We mark the process as running here. This guarantees that |
06b83b5f PZ |
1665 | * nobody will actually run it, and a signal or other external |
1666 | * event cannot wake it up and insert it on the runqueue either. | |
1667 | */ | |
0017d735 | 1668 | p->state = TASK_RUNNING; |
dd41f596 | 1669 | |
c350a04e MG |
1670 | /* |
1671 | * Make sure we do not leak PI boosting priority to the child. | |
1672 | */ | |
1673 | p->prio = current->normal_prio; | |
1674 | ||
b9dc29e7 MG |
1675 | /* |
1676 | * Revert to default priority/policy on fork if requested. | |
1677 | */ | |
1678 | if (unlikely(p->sched_reset_on_fork)) { | |
c350a04e | 1679 | if (task_has_rt_policy(p)) { |
b9dc29e7 | 1680 | p->policy = SCHED_NORMAL; |
6c697bdf | 1681 | p->static_prio = NICE_TO_PRIO(0); |
c350a04e MG |
1682 | p->rt_priority = 0; |
1683 | } else if (PRIO_TO_NICE(p->static_prio) < 0) | |
1684 | p->static_prio = NICE_TO_PRIO(0); | |
1685 | ||
1686 | p->prio = p->normal_prio = __normal_prio(p); | |
1687 | set_load_weight(p); | |
6c697bdf | 1688 | |
b9dc29e7 MG |
1689 | /* |
1690 | * We don't need the reset flag anymore after the fork. It has | |
1691 | * fulfilled its duty: | |
1692 | */ | |
1693 | p->sched_reset_on_fork = 0; | |
1694 | } | |
ca94c442 | 1695 | |
2ddbf952 HS |
1696 | if (!rt_prio(p->prio)) |
1697 | p->sched_class = &fair_sched_class; | |
b29739f9 | 1698 | |
cd29fe6f PZ |
1699 | if (p->sched_class->task_fork) |
1700 | p->sched_class->task_fork(p); | |
1701 | ||
86951599 PZ |
1702 | /* |
1703 | * The child is not yet in the pid-hash so no cgroup attach races, | |
1704 | * and the cgroup is pinned to this child due to cgroup_fork() | |
1705 | * is ran before sched_fork(). | |
1706 | * | |
1707 | * Silence PROVE_RCU. | |
1708 | */ | |
0122ec5b | 1709 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
5f3edc1b | 1710 | set_task_cpu(p, cpu); |
0122ec5b | 1711 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
5f3edc1b | 1712 | |
52f17b6c | 1713 | #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
dd41f596 | 1714 | if (likely(sched_info_on())) |
52f17b6c | 1715 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 1716 | #endif |
3ca7a440 PZ |
1717 | #if defined(CONFIG_SMP) |
1718 | p->on_cpu = 0; | |
4866cde0 | 1719 | #endif |
bdd4e85d | 1720 | #ifdef CONFIG_PREEMPT_COUNT |
4866cde0 | 1721 | /* Want to start with kernel preemption disabled. */ |
a1261f54 | 1722 | task_thread_info(p)->preempt_count = 1; |
1da177e4 | 1723 | #endif |
806c09a7 | 1724 | #ifdef CONFIG_SMP |
917b627d | 1725 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
806c09a7 | 1726 | #endif |
917b627d | 1727 | |
476d139c | 1728 | put_cpu(); |
1da177e4 LT |
1729 | } |
1730 | ||
1731 | /* | |
1732 | * wake_up_new_task - wake up a newly created task for the first time. | |
1733 | * | |
1734 | * This function will do some initial scheduler statistics housekeeping | |
1735 | * that must be done for every newly created context, then puts the task | |
1736 | * on the runqueue and wakes it. | |
1737 | */ | |
3e51e3ed | 1738 | void wake_up_new_task(struct task_struct *p) |
1da177e4 LT |
1739 | { |
1740 | unsigned long flags; | |
dd41f596 | 1741 | struct rq *rq; |
fabf318e | 1742 | |
ab2515c4 | 1743 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
fabf318e PZ |
1744 | #ifdef CONFIG_SMP |
1745 | /* | |
1746 | * Fork balancing, do it here and not earlier because: | |
1747 | * - cpus_allowed can change in the fork path | |
1748 | * - any previously selected cpu might disappear through hotplug | |
fabf318e | 1749 | */ |
ab2515c4 | 1750 | set_task_cpu(p, select_task_rq(p, SD_BALANCE_FORK, 0)); |
0017d735 PZ |
1751 | #endif |
1752 | ||
a75cdaa9 AS |
1753 | /* Initialize new task's runnable average */ |
1754 | init_task_runnable_average(p); | |
ab2515c4 | 1755 | rq = __task_rq_lock(p); |
cd29fe6f | 1756 | activate_task(rq, p, 0); |
fd2f4419 | 1757 | p->on_rq = 1; |
89363381 | 1758 | trace_sched_wakeup_new(p, true); |
a7558e01 | 1759 | check_preempt_curr(rq, p, WF_FORK); |
9a897c5a | 1760 | #ifdef CONFIG_SMP |
efbbd05a PZ |
1761 | if (p->sched_class->task_woken) |
1762 | p->sched_class->task_woken(rq, p); | |
9a897c5a | 1763 | #endif |
0122ec5b | 1764 | task_rq_unlock(rq, p, &flags); |
1da177e4 LT |
1765 | } |
1766 | ||
e107be36 AK |
1767 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
1768 | ||
1769 | /** | |
80dd99b3 | 1770 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
421cee29 | 1771 | * @notifier: notifier struct to register |
e107be36 AK |
1772 | */ |
1773 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
1774 | { | |
1775 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); | |
1776 | } | |
1777 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
1778 | ||
1779 | /** | |
1780 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 1781 | * @notifier: notifier struct to unregister |
e107be36 AK |
1782 | * |
1783 | * This is safe to call from within a preemption notifier. | |
1784 | */ | |
1785 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
1786 | { | |
1787 | hlist_del(¬ifier->link); | |
1788 | } | |
1789 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
1790 | ||
1791 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1792 | { | |
1793 | struct preempt_notifier *notifier; | |
e107be36 | 1794 | |
b67bfe0d | 1795 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
1796 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
1797 | } | |
1798 | ||
1799 | static void | |
1800 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1801 | struct task_struct *next) | |
1802 | { | |
1803 | struct preempt_notifier *notifier; | |
e107be36 | 1804 | |
b67bfe0d | 1805 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
1806 | notifier->ops->sched_out(notifier, next); |
1807 | } | |
1808 | ||
6d6bc0ad | 1809 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 AK |
1810 | |
1811 | static void fire_sched_in_preempt_notifiers(struct task_struct *curr) | |
1812 | { | |
1813 | } | |
1814 | ||
1815 | static void | |
1816 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
1817 | struct task_struct *next) | |
1818 | { | |
1819 | } | |
1820 | ||
6d6bc0ad | 1821 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 | 1822 | |
4866cde0 NP |
1823 | /** |
1824 | * prepare_task_switch - prepare to switch tasks | |
1825 | * @rq: the runqueue preparing to switch | |
421cee29 | 1826 | * @prev: the current task that is being switched out |
4866cde0 NP |
1827 | * @next: the task we are going to switch to. |
1828 | * | |
1829 | * This is called with the rq lock held and interrupts off. It must | |
1830 | * be paired with a subsequent finish_task_switch after the context | |
1831 | * switch. | |
1832 | * | |
1833 | * prepare_task_switch sets up locking and calls architecture specific | |
1834 | * hooks. | |
1835 | */ | |
e107be36 AK |
1836 | static inline void |
1837 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
1838 | struct task_struct *next) | |
4866cde0 | 1839 | { |
895dd92c | 1840 | trace_sched_switch(prev, next); |
fe4b04fa PZ |
1841 | sched_info_switch(prev, next); |
1842 | perf_event_task_sched_out(prev, next); | |
e107be36 | 1843 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
1844 | prepare_lock_switch(rq, next); |
1845 | prepare_arch_switch(next); | |
1846 | } | |
1847 | ||
1da177e4 LT |
1848 | /** |
1849 | * finish_task_switch - clean up after a task-switch | |
344babaa | 1850 | * @rq: runqueue associated with task-switch |
1da177e4 LT |
1851 | * @prev: the thread we just switched away from. |
1852 | * | |
4866cde0 NP |
1853 | * finish_task_switch must be called after the context switch, paired |
1854 | * with a prepare_task_switch call before the context switch. | |
1855 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
1856 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
1857 | * |
1858 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 1859 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
1860 | * with the lock held can cause deadlocks; see schedule() for |
1861 | * details.) | |
1862 | */ | |
a9957449 | 1863 | static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
1da177e4 LT |
1864 | __releases(rq->lock) |
1865 | { | |
1da177e4 | 1866 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 1867 | long prev_state; |
1da177e4 LT |
1868 | |
1869 | rq->prev_mm = NULL; | |
1870 | ||
1871 | /* | |
1872 | * A task struct has one reference for the use as "current". | |
c394cc9f | 1873 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
1874 | * schedule one last time. The schedule call will never return, and |
1875 | * the scheduled task must drop that reference. | |
c394cc9f | 1876 | * The test for TASK_DEAD must occur while the runqueue locks are |
1da177e4 LT |
1877 | * still held, otherwise prev could be scheduled on another cpu, die |
1878 | * there before we look at prev->state, and then the reference would | |
1879 | * be dropped twice. | |
1880 | * Manfred Spraul <manfred@colorfullife.com> | |
1881 | */ | |
55a101f8 | 1882 | prev_state = prev->state; |
bf9fae9f | 1883 | vtime_task_switch(prev); |
4866cde0 | 1884 | finish_arch_switch(prev); |
a8d757ef | 1885 | perf_event_task_sched_in(prev, current); |
4866cde0 | 1886 | finish_lock_switch(rq, prev); |
01f23e16 | 1887 | finish_arch_post_lock_switch(); |
e8fa1362 | 1888 | |
e107be36 | 1889 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
1890 | if (mm) |
1891 | mmdrop(mm); | |
c394cc9f | 1892 | if (unlikely(prev_state == TASK_DEAD)) { |
c6fd91f0 | 1893 | /* |
1894 | * Remove function-return probe instances associated with this | |
1895 | * task and put them back on the free list. | |
9761eea8 | 1896 | */ |
c6fd91f0 | 1897 | kprobe_flush_task(prev); |
1da177e4 | 1898 | put_task_struct(prev); |
c6fd91f0 | 1899 | } |
99e5ada9 FW |
1900 | |
1901 | tick_nohz_task_switch(current); | |
1da177e4 LT |
1902 | } |
1903 | ||
3f029d3c GH |
1904 | #ifdef CONFIG_SMP |
1905 | ||
1906 | /* assumes rq->lock is held */ | |
1907 | static inline void pre_schedule(struct rq *rq, struct task_struct *prev) | |
1908 | { | |
1909 | if (prev->sched_class->pre_schedule) | |
1910 | prev->sched_class->pre_schedule(rq, prev); | |
1911 | } | |
1912 | ||
1913 | /* rq->lock is NOT held, but preemption is disabled */ | |
1914 | static inline void post_schedule(struct rq *rq) | |
1915 | { | |
1916 | if (rq->post_schedule) { | |
1917 | unsigned long flags; | |
1918 | ||
05fa785c | 1919 | raw_spin_lock_irqsave(&rq->lock, flags); |
3f029d3c GH |
1920 | if (rq->curr->sched_class->post_schedule) |
1921 | rq->curr->sched_class->post_schedule(rq); | |
05fa785c | 1922 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
3f029d3c GH |
1923 | |
1924 | rq->post_schedule = 0; | |
1925 | } | |
1926 | } | |
1927 | ||
1928 | #else | |
da19ab51 | 1929 | |
3f029d3c GH |
1930 | static inline void pre_schedule(struct rq *rq, struct task_struct *p) |
1931 | { | |
1932 | } | |
1933 | ||
1934 | static inline void post_schedule(struct rq *rq) | |
1935 | { | |
1da177e4 LT |
1936 | } |
1937 | ||
3f029d3c GH |
1938 | #endif |
1939 | ||
1da177e4 LT |
1940 | /** |
1941 | * schedule_tail - first thing a freshly forked thread must call. | |
1942 | * @prev: the thread we just switched away from. | |
1943 | */ | |
36c8b586 | 1944 | asmlinkage void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
1945 | __releases(rq->lock) |
1946 | { | |
70b97a7f IM |
1947 | struct rq *rq = this_rq(); |
1948 | ||
4866cde0 | 1949 | finish_task_switch(rq, prev); |
da19ab51 | 1950 | |
3f029d3c GH |
1951 | /* |
1952 | * FIXME: do we need to worry about rq being invalidated by the | |
1953 | * task_switch? | |
1954 | */ | |
1955 | post_schedule(rq); | |
70b97a7f | 1956 | |
4866cde0 NP |
1957 | #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
1958 | /* In this case, finish_task_switch does not reenable preemption */ | |
1959 | preempt_enable(); | |
1960 | #endif | |
1da177e4 | 1961 | if (current->set_child_tid) |
b488893a | 1962 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
1963 | } |
1964 | ||
1965 | /* | |
1966 | * context_switch - switch to the new MM and the new | |
1967 | * thread's register state. | |
1968 | */ | |
dd41f596 | 1969 | static inline void |
70b97a7f | 1970 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 1971 | struct task_struct *next) |
1da177e4 | 1972 | { |
dd41f596 | 1973 | struct mm_struct *mm, *oldmm; |
1da177e4 | 1974 | |
e107be36 | 1975 | prepare_task_switch(rq, prev, next); |
fe4b04fa | 1976 | |
dd41f596 IM |
1977 | mm = next->mm; |
1978 | oldmm = prev->active_mm; | |
9226d125 ZA |
1979 | /* |
1980 | * For paravirt, this is coupled with an exit in switch_to to | |
1981 | * combine the page table reload and the switch backend into | |
1982 | * one hypercall. | |
1983 | */ | |
224101ed | 1984 | arch_start_context_switch(prev); |
9226d125 | 1985 | |
31915ab4 | 1986 | if (!mm) { |
1da177e4 LT |
1987 | next->active_mm = oldmm; |
1988 | atomic_inc(&oldmm->mm_count); | |
1989 | enter_lazy_tlb(oldmm, next); | |
1990 | } else | |
1991 | switch_mm(oldmm, mm, next); | |
1992 | ||
31915ab4 | 1993 | if (!prev->mm) { |
1da177e4 | 1994 | prev->active_mm = NULL; |
1da177e4 LT |
1995 | rq->prev_mm = oldmm; |
1996 | } | |
3a5f5e48 IM |
1997 | /* |
1998 | * Since the runqueue lock will be released by the next | |
1999 | * task (which is an invalid locking op but in the case | |
2000 | * of the scheduler it's an obvious special-case), so we | |
2001 | * do an early lockdep release here: | |
2002 | */ | |
2003 | #ifndef __ARCH_WANT_UNLOCKED_CTXSW | |
8a25d5de | 2004 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
3a5f5e48 | 2005 | #endif |
1da177e4 | 2006 | |
91d1aa43 | 2007 | context_tracking_task_switch(prev, next); |
1da177e4 LT |
2008 | /* Here we just switch the register state and the stack. */ |
2009 | switch_to(prev, next, prev); | |
2010 | ||
dd41f596 IM |
2011 | barrier(); |
2012 | /* | |
2013 | * this_rq must be evaluated again because prev may have moved | |
2014 | * CPUs since it called schedule(), thus the 'rq' on its stack | |
2015 | * frame will be invalid. | |
2016 | */ | |
2017 | finish_task_switch(this_rq(), prev); | |
1da177e4 LT |
2018 | } |
2019 | ||
2020 | /* | |
1c3e8264 | 2021 | * nr_running and nr_context_switches: |
1da177e4 LT |
2022 | * |
2023 | * externally visible scheduler statistics: current number of runnable | |
1c3e8264 | 2024 | * threads, total number of context switches performed since bootup. |
1da177e4 LT |
2025 | */ |
2026 | unsigned long nr_running(void) | |
2027 | { | |
2028 | unsigned long i, sum = 0; | |
2029 | ||
2030 | for_each_online_cpu(i) | |
2031 | sum += cpu_rq(i)->nr_running; | |
2032 | ||
2033 | return sum; | |
f711f609 | 2034 | } |
1da177e4 | 2035 | |
1da177e4 | 2036 | unsigned long long nr_context_switches(void) |
46cb4b7c | 2037 | { |
cc94abfc SR |
2038 | int i; |
2039 | unsigned long long sum = 0; | |
46cb4b7c | 2040 | |
0a945022 | 2041 | for_each_possible_cpu(i) |
1da177e4 | 2042 | sum += cpu_rq(i)->nr_switches; |
46cb4b7c | 2043 | |
1da177e4 LT |
2044 | return sum; |
2045 | } | |
483b4ee6 | 2046 | |
1da177e4 LT |
2047 | unsigned long nr_iowait(void) |
2048 | { | |
2049 | unsigned long i, sum = 0; | |
483b4ee6 | 2050 | |
0a945022 | 2051 | for_each_possible_cpu(i) |
1da177e4 | 2052 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
46cb4b7c | 2053 | |
1da177e4 LT |
2054 | return sum; |
2055 | } | |
483b4ee6 | 2056 | |
8c215bd3 | 2057 | unsigned long nr_iowait_cpu(int cpu) |
69d25870 | 2058 | { |
8c215bd3 | 2059 | struct rq *this = cpu_rq(cpu); |
69d25870 AV |
2060 | return atomic_read(&this->nr_iowait); |
2061 | } | |
46cb4b7c | 2062 | |
dd41f596 | 2063 | #ifdef CONFIG_SMP |
8a0be9ef | 2064 | |
46cb4b7c | 2065 | /* |
38022906 PZ |
2066 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2067 | * this point the task has the smallest effective memory and cache footprint. | |
46cb4b7c | 2068 | */ |
38022906 | 2069 | void sched_exec(void) |
46cb4b7c | 2070 | { |
38022906 | 2071 | struct task_struct *p = current; |
1da177e4 | 2072 | unsigned long flags; |
0017d735 | 2073 | int dest_cpu; |
46cb4b7c | 2074 | |
8f42ced9 | 2075 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
7608dec2 | 2076 | dest_cpu = p->sched_class->select_task_rq(p, SD_BALANCE_EXEC, 0); |
0017d735 PZ |
2077 | if (dest_cpu == smp_processor_id()) |
2078 | goto unlock; | |
38022906 | 2079 | |
8f42ced9 | 2080 | if (likely(cpu_active(dest_cpu))) { |
969c7921 | 2081 | struct migration_arg arg = { p, dest_cpu }; |
46cb4b7c | 2082 | |
8f42ced9 PZ |
2083 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
2084 | stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); | |
1da177e4 LT |
2085 | return; |
2086 | } | |
0017d735 | 2087 | unlock: |
8f42ced9 | 2088 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 | 2089 | } |
dd41f596 | 2090 | |
1da177e4 LT |
2091 | #endif |
2092 | ||
1da177e4 | 2093 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3292beb3 | 2094 | DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); |
1da177e4 LT |
2095 | |
2096 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3292beb3 | 2097 | EXPORT_PER_CPU_SYMBOL(kernel_cpustat); |
1da177e4 LT |
2098 | |
2099 | /* | |
c5f8d995 | 2100 | * Return any ns on the sched_clock that have not yet been accounted in |
f06febc9 | 2101 | * @p in case that task is currently running. |
c5f8d995 HS |
2102 | * |
2103 | * Called with task_rq_lock() held on @rq. | |
1da177e4 | 2104 | */ |
c5f8d995 HS |
2105 | static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq) |
2106 | { | |
2107 | u64 ns = 0; | |
2108 | ||
2109 | if (task_current(rq, p)) { | |
2110 | update_rq_clock(rq); | |
78becc27 | 2111 | ns = rq_clock_task(rq) - p->se.exec_start; |
c5f8d995 HS |
2112 | if ((s64)ns < 0) |
2113 | ns = 0; | |
2114 | } | |
2115 | ||
2116 | return ns; | |
2117 | } | |
2118 | ||
bb34d92f | 2119 | unsigned long long task_delta_exec(struct task_struct *p) |
1da177e4 | 2120 | { |
1da177e4 | 2121 | unsigned long flags; |
41b86e9c | 2122 | struct rq *rq; |
bb34d92f | 2123 | u64 ns = 0; |
48f24c4d | 2124 | |
41b86e9c | 2125 | rq = task_rq_lock(p, &flags); |
c5f8d995 | 2126 | ns = do_task_delta_exec(p, rq); |
0122ec5b | 2127 | task_rq_unlock(rq, p, &flags); |
1508487e | 2128 | |
c5f8d995 HS |
2129 | return ns; |
2130 | } | |
f06febc9 | 2131 | |
c5f8d995 HS |
2132 | /* |
2133 | * Return accounted runtime for the task. | |
2134 | * In case the task is currently running, return the runtime plus current's | |
2135 | * pending runtime that have not been accounted yet. | |
2136 | */ | |
2137 | unsigned long long task_sched_runtime(struct task_struct *p) | |
2138 | { | |
2139 | unsigned long flags; | |
2140 | struct rq *rq; | |
2141 | u64 ns = 0; | |
2142 | ||
2143 | rq = task_rq_lock(p, &flags); | |
2144 | ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq); | |
0122ec5b | 2145 | task_rq_unlock(rq, p, &flags); |
c5f8d995 HS |
2146 | |
2147 | return ns; | |
2148 | } | |
48f24c4d | 2149 | |
7835b98b CL |
2150 | /* |
2151 | * This function gets called by the timer code, with HZ frequency. | |
2152 | * We call it with interrupts disabled. | |
7835b98b CL |
2153 | */ |
2154 | void scheduler_tick(void) | |
2155 | { | |
7835b98b CL |
2156 | int cpu = smp_processor_id(); |
2157 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 2158 | struct task_struct *curr = rq->curr; |
3e51f33f PZ |
2159 | |
2160 | sched_clock_tick(); | |
dd41f596 | 2161 | |
05fa785c | 2162 | raw_spin_lock(&rq->lock); |
3e51f33f | 2163 | update_rq_clock(rq); |
fa85ae24 | 2164 | curr->sched_class->task_tick(rq, curr, 0); |
83dfd523 | 2165 | update_cpu_load_active(rq); |
05fa785c | 2166 | raw_spin_unlock(&rq->lock); |
7835b98b | 2167 | |
e9d2b064 | 2168 | perf_event_task_tick(); |
e220d2dc | 2169 | |
e418e1c2 | 2170 | #ifdef CONFIG_SMP |
6eb57e0d | 2171 | rq->idle_balance = idle_cpu(cpu); |
dd41f596 | 2172 | trigger_load_balance(rq, cpu); |
e418e1c2 | 2173 | #endif |
265f22a9 | 2174 | rq_last_tick_reset(rq); |
1da177e4 LT |
2175 | } |
2176 | ||
265f22a9 FW |
2177 | #ifdef CONFIG_NO_HZ_FULL |
2178 | /** | |
2179 | * scheduler_tick_max_deferment | |
2180 | * | |
2181 | * Keep at least one tick per second when a single | |
2182 | * active task is running because the scheduler doesn't | |
2183 | * yet completely support full dynticks environment. | |
2184 | * | |
2185 | * This makes sure that uptime, CFS vruntime, load | |
2186 | * balancing, etc... continue to move forward, even | |
2187 | * with a very low granularity. | |
e69f6186 YB |
2188 | * |
2189 | * Return: Maximum deferment in nanoseconds. | |
265f22a9 FW |
2190 | */ |
2191 | u64 scheduler_tick_max_deferment(void) | |
2192 | { | |
2193 | struct rq *rq = this_rq(); | |
2194 | unsigned long next, now = ACCESS_ONCE(jiffies); | |
2195 | ||
2196 | next = rq->last_sched_tick + HZ; | |
2197 | ||
2198 | if (time_before_eq(next, now)) | |
2199 | return 0; | |
2200 | ||
2201 | return jiffies_to_usecs(next - now) * NSEC_PER_USEC; | |
1da177e4 | 2202 | } |
265f22a9 | 2203 | #endif |
1da177e4 | 2204 | |
132380a0 | 2205 | notrace unsigned long get_parent_ip(unsigned long addr) |
6cd8a4bb SR |
2206 | { |
2207 | if (in_lock_functions(addr)) { | |
2208 | addr = CALLER_ADDR2; | |
2209 | if (in_lock_functions(addr)) | |
2210 | addr = CALLER_ADDR3; | |
2211 | } | |
2212 | return addr; | |
2213 | } | |
1da177e4 | 2214 | |
7e49fcce SR |
2215 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
2216 | defined(CONFIG_PREEMPT_TRACER)) | |
2217 | ||
43627582 | 2218 | void __kprobes add_preempt_count(int val) |
1da177e4 | 2219 | { |
6cd8a4bb | 2220 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
2221 | /* |
2222 | * Underflow? | |
2223 | */ | |
9a11b49a IM |
2224 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
2225 | return; | |
6cd8a4bb | 2226 | #endif |
1da177e4 | 2227 | preempt_count() += val; |
6cd8a4bb | 2228 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
2229 | /* |
2230 | * Spinlock count overflowing soon? | |
2231 | */ | |
33859f7f MOS |
2232 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
2233 | PREEMPT_MASK - 10); | |
6cd8a4bb SR |
2234 | #endif |
2235 | if (preempt_count() == val) | |
2236 | trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); | |
1da177e4 LT |
2237 | } |
2238 | EXPORT_SYMBOL(add_preempt_count); | |
2239 | ||
43627582 | 2240 | void __kprobes sub_preempt_count(int val) |
1da177e4 | 2241 | { |
6cd8a4bb | 2242 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
2243 | /* |
2244 | * Underflow? | |
2245 | */ | |
01e3eb82 | 2246 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
9a11b49a | 2247 | return; |
1da177e4 LT |
2248 | /* |
2249 | * Is the spinlock portion underflowing? | |
2250 | */ | |
9a11b49a IM |
2251 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
2252 | !(preempt_count() & PREEMPT_MASK))) | |
2253 | return; | |
6cd8a4bb | 2254 | #endif |
9a11b49a | 2255 | |
6cd8a4bb SR |
2256 | if (preempt_count() == val) |
2257 | trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); | |
1da177e4 LT |
2258 | preempt_count() -= val; |
2259 | } | |
2260 | EXPORT_SYMBOL(sub_preempt_count); | |
2261 | ||
2262 | #endif | |
2263 | ||
2264 | /* | |
dd41f596 | 2265 | * Print scheduling while atomic bug: |
1da177e4 | 2266 | */ |
dd41f596 | 2267 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 2268 | { |
664dfa65 DJ |
2269 | if (oops_in_progress) |
2270 | return; | |
2271 | ||
3df0fc5b PZ |
2272 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
2273 | prev->comm, prev->pid, preempt_count()); | |
838225b4 | 2274 | |
dd41f596 | 2275 | debug_show_held_locks(prev); |
e21f5b15 | 2276 | print_modules(); |
dd41f596 IM |
2277 | if (irqs_disabled()) |
2278 | print_irqtrace_events(prev); | |
6135fc1e | 2279 | dump_stack(); |
373d4d09 | 2280 | add_taint(TAINT_WARN, LOCKDEP_STILL_OK); |
dd41f596 | 2281 | } |
1da177e4 | 2282 | |
dd41f596 IM |
2283 | /* |
2284 | * Various schedule()-time debugging checks and statistics: | |
2285 | */ | |
2286 | static inline void schedule_debug(struct task_struct *prev) | |
2287 | { | |
1da177e4 | 2288 | /* |
41a2d6cf | 2289 | * Test if we are atomic. Since do_exit() needs to call into |
1da177e4 LT |
2290 | * schedule() atomically, we ignore that path for now. |
2291 | * Otherwise, whine if we are scheduling when we should not be. | |
2292 | */ | |
3f33a7ce | 2293 | if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) |
dd41f596 | 2294 | __schedule_bug(prev); |
b3fbab05 | 2295 | rcu_sleep_check(); |
dd41f596 | 2296 | |
1da177e4 LT |
2297 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
2298 | ||
2d72376b | 2299 | schedstat_inc(this_rq(), sched_count); |
dd41f596 IM |
2300 | } |
2301 | ||
6cecd084 | 2302 | static void put_prev_task(struct rq *rq, struct task_struct *prev) |
df1c99d4 | 2303 | { |
61eadef6 | 2304 | if (prev->on_rq || rq->skip_clock_update < 0) |
a64692a3 | 2305 | update_rq_clock(rq); |
6cecd084 | 2306 | prev->sched_class->put_prev_task(rq, prev); |
df1c99d4 MG |
2307 | } |
2308 | ||
dd41f596 IM |
2309 | /* |
2310 | * Pick up the highest-prio task: | |
2311 | */ | |
2312 | static inline struct task_struct * | |
b67802ea | 2313 | pick_next_task(struct rq *rq) |
dd41f596 | 2314 | { |
5522d5d5 | 2315 | const struct sched_class *class; |
dd41f596 | 2316 | struct task_struct *p; |
1da177e4 LT |
2317 | |
2318 | /* | |
dd41f596 IM |
2319 | * Optimization: we know that if all tasks are in |
2320 | * the fair class we can call that function directly: | |
1da177e4 | 2321 | */ |
953bfcd1 | 2322 | if (likely(rq->nr_running == rq->cfs.h_nr_running)) { |
fb8d4724 | 2323 | p = fair_sched_class.pick_next_task(rq); |
dd41f596 IM |
2324 | if (likely(p)) |
2325 | return p; | |
1da177e4 LT |
2326 | } |
2327 | ||
34f971f6 | 2328 | for_each_class(class) { |
fb8d4724 | 2329 | p = class->pick_next_task(rq); |
dd41f596 IM |
2330 | if (p) |
2331 | return p; | |
dd41f596 | 2332 | } |
34f971f6 PZ |
2333 | |
2334 | BUG(); /* the idle class will always have a runnable task */ | |
dd41f596 | 2335 | } |
1da177e4 | 2336 | |
dd41f596 | 2337 | /* |
c259e01a | 2338 | * __schedule() is the main scheduler function. |
edde96ea PE |
2339 | * |
2340 | * The main means of driving the scheduler and thus entering this function are: | |
2341 | * | |
2342 | * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. | |
2343 | * | |
2344 | * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return | |
2345 | * paths. For example, see arch/x86/entry_64.S. | |
2346 | * | |
2347 | * To drive preemption between tasks, the scheduler sets the flag in timer | |
2348 | * interrupt handler scheduler_tick(). | |
2349 | * | |
2350 | * 3. Wakeups don't really cause entry into schedule(). They add a | |
2351 | * task to the run-queue and that's it. | |
2352 | * | |
2353 | * Now, if the new task added to the run-queue preempts the current | |
2354 | * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets | |
2355 | * called on the nearest possible occasion: | |
2356 | * | |
2357 | * - If the kernel is preemptible (CONFIG_PREEMPT=y): | |
2358 | * | |
2359 | * - in syscall or exception context, at the next outmost | |
2360 | * preempt_enable(). (this might be as soon as the wake_up()'s | |
2361 | * spin_unlock()!) | |
2362 | * | |
2363 | * - in IRQ context, return from interrupt-handler to | |
2364 | * preemptible context | |
2365 | * | |
2366 | * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) | |
2367 | * then at the next: | |
2368 | * | |
2369 | * - cond_resched() call | |
2370 | * - explicit schedule() call | |
2371 | * - return from syscall or exception to user-space | |
2372 | * - return from interrupt-handler to user-space | |
dd41f596 | 2373 | */ |
c259e01a | 2374 | static void __sched __schedule(void) |
dd41f596 IM |
2375 | { |
2376 | struct task_struct *prev, *next; | |
67ca7bde | 2377 | unsigned long *switch_count; |
dd41f596 | 2378 | struct rq *rq; |
31656519 | 2379 | int cpu; |
dd41f596 | 2380 | |
ff743345 PZ |
2381 | need_resched: |
2382 | preempt_disable(); | |
dd41f596 IM |
2383 | cpu = smp_processor_id(); |
2384 | rq = cpu_rq(cpu); | |
25502a6c | 2385 | rcu_note_context_switch(cpu); |
dd41f596 | 2386 | prev = rq->curr; |
dd41f596 | 2387 | |
dd41f596 | 2388 | schedule_debug(prev); |
1da177e4 | 2389 | |
31656519 | 2390 | if (sched_feat(HRTICK)) |
f333fdc9 | 2391 | hrtick_clear(rq); |
8f4d37ec | 2392 | |
e0acd0a6 ON |
2393 | /* |
2394 | * Make sure that signal_pending_state()->signal_pending() below | |
2395 | * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) | |
2396 | * done by the caller to avoid the race with signal_wake_up(). | |
2397 | */ | |
2398 | smp_mb__before_spinlock(); | |
05fa785c | 2399 | raw_spin_lock_irq(&rq->lock); |
1da177e4 | 2400 | |
246d86b5 | 2401 | switch_count = &prev->nivcsw; |
1da177e4 | 2402 | if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
21aa9af0 | 2403 | if (unlikely(signal_pending_state(prev->state, prev))) { |
1da177e4 | 2404 | prev->state = TASK_RUNNING; |
21aa9af0 | 2405 | } else { |
2acca55e PZ |
2406 | deactivate_task(rq, prev, DEQUEUE_SLEEP); |
2407 | prev->on_rq = 0; | |
2408 | ||
21aa9af0 | 2409 | /* |
2acca55e PZ |
2410 | * If a worker went to sleep, notify and ask workqueue |
2411 | * whether it wants to wake up a task to maintain | |
2412 | * concurrency. | |
21aa9af0 TH |
2413 | */ |
2414 | if (prev->flags & PF_WQ_WORKER) { | |
2415 | struct task_struct *to_wakeup; | |
2416 | ||
2417 | to_wakeup = wq_worker_sleeping(prev, cpu); | |
2418 | if (to_wakeup) | |
2419 | try_to_wake_up_local(to_wakeup); | |
2420 | } | |
21aa9af0 | 2421 | } |
dd41f596 | 2422 | switch_count = &prev->nvcsw; |
1da177e4 LT |
2423 | } |
2424 | ||
3f029d3c | 2425 | pre_schedule(rq, prev); |
f65eda4f | 2426 | |
dd41f596 | 2427 | if (unlikely(!rq->nr_running)) |
1da177e4 | 2428 | idle_balance(cpu, rq); |
1da177e4 | 2429 | |
df1c99d4 | 2430 | put_prev_task(rq, prev); |
b67802ea | 2431 | next = pick_next_task(rq); |
f26f9aff MG |
2432 | clear_tsk_need_resched(prev); |
2433 | rq->skip_clock_update = 0; | |
1da177e4 | 2434 | |
1da177e4 | 2435 | if (likely(prev != next)) { |
1da177e4 LT |
2436 | rq->nr_switches++; |
2437 | rq->curr = next; | |
2438 | ++*switch_count; | |
2439 | ||
dd41f596 | 2440 | context_switch(rq, prev, next); /* unlocks the rq */ |
8f4d37ec | 2441 | /* |
246d86b5 ON |
2442 | * The context switch have flipped the stack from under us |
2443 | * and restored the local variables which were saved when | |
2444 | * this task called schedule() in the past. prev == current | |
2445 | * is still correct, but it can be moved to another cpu/rq. | |
8f4d37ec PZ |
2446 | */ |
2447 | cpu = smp_processor_id(); | |
2448 | rq = cpu_rq(cpu); | |
1da177e4 | 2449 | } else |
05fa785c | 2450 | raw_spin_unlock_irq(&rq->lock); |
1da177e4 | 2451 | |
3f029d3c | 2452 | post_schedule(rq); |
1da177e4 | 2453 | |
ba74c144 | 2454 | sched_preempt_enable_no_resched(); |
ff743345 | 2455 | if (need_resched()) |
1da177e4 LT |
2456 | goto need_resched; |
2457 | } | |
c259e01a | 2458 | |
9c40cef2 TG |
2459 | static inline void sched_submit_work(struct task_struct *tsk) |
2460 | { | |
3c7d5184 | 2461 | if (!tsk->state || tsk_is_pi_blocked(tsk)) |
9c40cef2 TG |
2462 | return; |
2463 | /* | |
2464 | * If we are going to sleep and we have plugged IO queued, | |
2465 | * make sure to submit it to avoid deadlocks. | |
2466 | */ | |
2467 | if (blk_needs_flush_plug(tsk)) | |
2468 | blk_schedule_flush_plug(tsk); | |
2469 | } | |
2470 | ||
6ebbe7a0 | 2471 | asmlinkage void __sched schedule(void) |
c259e01a | 2472 | { |
9c40cef2 TG |
2473 | struct task_struct *tsk = current; |
2474 | ||
2475 | sched_submit_work(tsk); | |
c259e01a TG |
2476 | __schedule(); |
2477 | } | |
1da177e4 LT |
2478 | EXPORT_SYMBOL(schedule); |
2479 | ||
91d1aa43 | 2480 | #ifdef CONFIG_CONTEXT_TRACKING |
20ab65e3 FW |
2481 | asmlinkage void __sched schedule_user(void) |
2482 | { | |
2483 | /* | |
2484 | * If we come here after a random call to set_need_resched(), | |
2485 | * or we have been woken up remotely but the IPI has not yet arrived, | |
2486 | * we haven't yet exited the RCU idle mode. Do it here manually until | |
2487 | * we find a better solution. | |
2488 | */ | |
91d1aa43 | 2489 | user_exit(); |
20ab65e3 | 2490 | schedule(); |
91d1aa43 | 2491 | user_enter(); |
20ab65e3 FW |
2492 | } |
2493 | #endif | |
2494 | ||
c5491ea7 TG |
2495 | /** |
2496 | * schedule_preempt_disabled - called with preemption disabled | |
2497 | * | |
2498 | * Returns with preemption disabled. Note: preempt_count must be 1 | |
2499 | */ | |
2500 | void __sched schedule_preempt_disabled(void) | |
2501 | { | |
ba74c144 | 2502 | sched_preempt_enable_no_resched(); |
c5491ea7 TG |
2503 | schedule(); |
2504 | preempt_disable(); | |
2505 | } | |
2506 | ||
1da177e4 LT |
2507 | #ifdef CONFIG_PREEMPT |
2508 | /* | |
2ed6e34f | 2509 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 2510 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
2511 | * occur there and call schedule directly. |
2512 | */ | |
d1f74e20 | 2513 | asmlinkage void __sched notrace preempt_schedule(void) |
1da177e4 | 2514 | { |
1da177e4 LT |
2515 | /* |
2516 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 2517 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 2518 | */ |
fbb00b56 | 2519 | if (likely(!preemptible())) |
1da177e4 LT |
2520 | return; |
2521 | ||
3a5c359a | 2522 | do { |
d1f74e20 | 2523 | add_preempt_count_notrace(PREEMPT_ACTIVE); |
c259e01a | 2524 | __schedule(); |
d1f74e20 | 2525 | sub_preempt_count_notrace(PREEMPT_ACTIVE); |
1da177e4 | 2526 | |
3a5c359a AK |
2527 | /* |
2528 | * Check again in case we missed a preemption opportunity | |
2529 | * between schedule and now. | |
2530 | */ | |
2531 | barrier(); | |
5ed0cec0 | 2532 | } while (need_resched()); |
1da177e4 | 2533 | } |
1da177e4 LT |
2534 | EXPORT_SYMBOL(preempt_schedule); |
2535 | ||
2536 | /* | |
2ed6e34f | 2537 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
2538 | * off of irq context. |
2539 | * Note, that this is called and return with irqs disabled. This will | |
2540 | * protect us against recursive calling from irq. | |
2541 | */ | |
2542 | asmlinkage void __sched preempt_schedule_irq(void) | |
2543 | { | |
2544 | struct thread_info *ti = current_thread_info(); | |
b22366cd | 2545 | enum ctx_state prev_state; |
6478d880 | 2546 | |
2ed6e34f | 2547 | /* Catch callers which need to be fixed */ |
1da177e4 LT |
2548 | BUG_ON(ti->preempt_count || !irqs_disabled()); |
2549 | ||
b22366cd FW |
2550 | prev_state = exception_enter(); |
2551 | ||
3a5c359a AK |
2552 | do { |
2553 | add_preempt_count(PREEMPT_ACTIVE); | |
3a5c359a | 2554 | local_irq_enable(); |
c259e01a | 2555 | __schedule(); |
3a5c359a | 2556 | local_irq_disable(); |
3a5c359a | 2557 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 | 2558 | |
3a5c359a AK |
2559 | /* |
2560 | * Check again in case we missed a preemption opportunity | |
2561 | * between schedule and now. | |
2562 | */ | |
2563 | barrier(); | |
5ed0cec0 | 2564 | } while (need_resched()); |
b22366cd FW |
2565 | |
2566 | exception_exit(prev_state); | |
1da177e4 LT |
2567 | } |
2568 | ||
2569 | #endif /* CONFIG_PREEMPT */ | |
2570 | ||
63859d4f | 2571 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
95cdf3b7 | 2572 | void *key) |
1da177e4 | 2573 | { |
63859d4f | 2574 | return try_to_wake_up(curr->private, mode, wake_flags); |
1da177e4 | 2575 | } |
1da177e4 LT |
2576 | EXPORT_SYMBOL(default_wake_function); |
2577 | ||
2578 | /* | |
41a2d6cf IM |
2579 | * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
2580 | * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve | |
1da177e4 LT |
2581 | * number) then we wake all the non-exclusive tasks and one exclusive task. |
2582 | * | |
2583 | * There are circumstances in which we can try to wake a task which has already | |
41a2d6cf | 2584 | * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
1da177e4 LT |
2585 | * zero in this (rare) case, and we handle it by continuing to scan the queue. |
2586 | */ | |
78ddb08f | 2587 | static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
63859d4f | 2588 | int nr_exclusive, int wake_flags, void *key) |
1da177e4 | 2589 | { |
2e45874c | 2590 | wait_queue_t *curr, *next; |
1da177e4 | 2591 | |
2e45874c | 2592 | list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
48f24c4d IM |
2593 | unsigned flags = curr->flags; |
2594 | ||
63859d4f | 2595 | if (curr->func(curr, mode, wake_flags, key) && |
48f24c4d | 2596 | (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
1da177e4 LT |
2597 | break; |
2598 | } | |
2599 | } | |
2600 | ||
2601 | /** | |
2602 | * __wake_up - wake up threads blocked on a waitqueue. | |
2603 | * @q: the waitqueue | |
2604 | * @mode: which threads | |
2605 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
67be2dd1 | 2606 | * @key: is directly passed to the wakeup function |
50fa610a DH |
2607 | * |
2608 | * It may be assumed that this function implies a write memory barrier before | |
2609 | * changing the task state if and only if any tasks are woken up. | |
1da177e4 | 2610 | */ |
7ad5b3a5 | 2611 | void __wake_up(wait_queue_head_t *q, unsigned int mode, |
95cdf3b7 | 2612 | int nr_exclusive, void *key) |
1da177e4 LT |
2613 | { |
2614 | unsigned long flags; | |
2615 | ||
2616 | spin_lock_irqsave(&q->lock, flags); | |
2617 | __wake_up_common(q, mode, nr_exclusive, 0, key); | |
2618 | spin_unlock_irqrestore(&q->lock, flags); | |
2619 | } | |
1da177e4 LT |
2620 | EXPORT_SYMBOL(__wake_up); |
2621 | ||
2622 | /* | |
2623 | * Same as __wake_up but called with the spinlock in wait_queue_head_t held. | |
2624 | */ | |
63b20011 | 2625 | void __wake_up_locked(wait_queue_head_t *q, unsigned int mode, int nr) |
1da177e4 | 2626 | { |
63b20011 | 2627 | __wake_up_common(q, mode, nr, 0, NULL); |
1da177e4 | 2628 | } |
22c43c81 | 2629 | EXPORT_SYMBOL_GPL(__wake_up_locked); |
1da177e4 | 2630 | |
4ede816a DL |
2631 | void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key) |
2632 | { | |
2633 | __wake_up_common(q, mode, 1, 0, key); | |
2634 | } | |
bf294b41 | 2635 | EXPORT_SYMBOL_GPL(__wake_up_locked_key); |
4ede816a | 2636 | |
1da177e4 | 2637 | /** |
4ede816a | 2638 | * __wake_up_sync_key - wake up threads blocked on a waitqueue. |
1da177e4 LT |
2639 | * @q: the waitqueue |
2640 | * @mode: which threads | |
2641 | * @nr_exclusive: how many wake-one or wake-many threads to wake up | |
4ede816a | 2642 | * @key: opaque value to be passed to wakeup targets |
1da177e4 LT |
2643 | * |
2644 | * The sync wakeup differs that the waker knows that it will schedule | |
2645 | * away soon, so while the target thread will be woken up, it will not | |
2646 | * be migrated to another CPU - ie. the two threads are 'synchronized' | |
2647 | * with each other. This can prevent needless bouncing between CPUs. | |
2648 | * | |
2649 | * On UP it can prevent extra preemption. | |
50fa610a DH |
2650 | * |
2651 | * It may be assumed that this function implies a write memory barrier before | |
2652 | * changing the task state if and only if any tasks are woken up. | |
1da177e4 | 2653 | */ |
4ede816a DL |
2654 | void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode, |
2655 | int nr_exclusive, void *key) | |
1da177e4 LT |
2656 | { |
2657 | unsigned long flags; | |
7d478721 | 2658 | int wake_flags = WF_SYNC; |
1da177e4 LT |
2659 | |
2660 | if (unlikely(!q)) | |
2661 | return; | |
2662 | ||
cedce3e7 | 2663 | if (unlikely(nr_exclusive != 1)) |
7d478721 | 2664 | wake_flags = 0; |
1da177e4 LT |
2665 | |
2666 | spin_lock_irqsave(&q->lock, flags); | |
7d478721 | 2667 | __wake_up_common(q, mode, nr_exclusive, wake_flags, key); |
1da177e4 LT |
2668 | spin_unlock_irqrestore(&q->lock, flags); |
2669 | } | |
4ede816a DL |
2670 | EXPORT_SYMBOL_GPL(__wake_up_sync_key); |
2671 | ||
2672 | /* | |
2673 | * __wake_up_sync - see __wake_up_sync_key() | |
2674 | */ | |
2675 | void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) | |
2676 | { | |
2677 | __wake_up_sync_key(q, mode, nr_exclusive, NULL); | |
2678 | } | |
1da177e4 LT |
2679 | EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
2680 | ||
65eb3dc6 KD |
2681 | /** |
2682 | * complete: - signals a single thread waiting on this completion | |
2683 | * @x: holds the state of this particular completion | |
2684 | * | |
2685 | * This will wake up a single thread waiting on this completion. Threads will be | |
2686 | * awakened in the same order in which they were queued. | |
2687 | * | |
2688 | * See also complete_all(), wait_for_completion() and related routines. | |
50fa610a DH |
2689 | * |
2690 | * It may be assumed that this function implies a write memory barrier before | |
2691 | * changing the task state if and only if any tasks are woken up. | |
65eb3dc6 | 2692 | */ |
b15136e9 | 2693 | void complete(struct completion *x) |
1da177e4 LT |
2694 | { |
2695 | unsigned long flags; | |
2696 | ||
2697 | spin_lock_irqsave(&x->wait.lock, flags); | |
2698 | x->done++; | |
d9514f6c | 2699 | __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); |
1da177e4 LT |
2700 | spin_unlock_irqrestore(&x->wait.lock, flags); |
2701 | } | |
2702 | EXPORT_SYMBOL(complete); | |
2703 | ||
65eb3dc6 KD |
2704 | /** |
2705 | * complete_all: - signals all threads waiting on this completion | |
2706 | * @x: holds the state of this particular completion | |
2707 | * | |
2708 | * This will wake up all threads waiting on this particular completion event. | |
50fa610a DH |
2709 | * |
2710 | * It may be assumed that this function implies a write memory barrier before | |
2711 | * changing the task state if and only if any tasks are woken up. | |
65eb3dc6 | 2712 | */ |
b15136e9 | 2713 | void complete_all(struct completion *x) |
1da177e4 LT |
2714 | { |
2715 | unsigned long flags; | |
2716 | ||
2717 | spin_lock_irqsave(&x->wait.lock, flags); | |
2718 | x->done += UINT_MAX/2; | |
d9514f6c | 2719 | __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); |
1da177e4 LT |
2720 | spin_unlock_irqrestore(&x->wait.lock, flags); |
2721 | } | |
2722 | EXPORT_SYMBOL(complete_all); | |
2723 | ||
8cbbe86d | 2724 | static inline long __sched |
686855f5 VD |
2725 | do_wait_for_common(struct completion *x, |
2726 | long (*action)(long), long timeout, int state) | |
1da177e4 | 2727 | { |
1da177e4 LT |
2728 | if (!x->done) { |
2729 | DECLARE_WAITQUEUE(wait, current); | |
2730 | ||
a93d2f17 | 2731 | __add_wait_queue_tail_exclusive(&x->wait, &wait); |
1da177e4 | 2732 | do { |
94d3d824 | 2733 | if (signal_pending_state(state, current)) { |
ea71a546 ON |
2734 | timeout = -ERESTARTSYS; |
2735 | break; | |
8cbbe86d AK |
2736 | } |
2737 | __set_current_state(state); | |
1da177e4 | 2738 | spin_unlock_irq(&x->wait.lock); |
686855f5 | 2739 | timeout = action(timeout); |
1da177e4 | 2740 | spin_lock_irq(&x->wait.lock); |
ea71a546 | 2741 | } while (!x->done && timeout); |
1da177e4 | 2742 | __remove_wait_queue(&x->wait, &wait); |
ea71a546 ON |
2743 | if (!x->done) |
2744 | return timeout; | |
1da177e4 LT |
2745 | } |
2746 | x->done--; | |
ea71a546 | 2747 | return timeout ?: 1; |
1da177e4 | 2748 | } |
1da177e4 | 2749 | |
686855f5 VD |
2750 | static inline long __sched |
2751 | __wait_for_common(struct completion *x, | |
2752 | long (*action)(long), long timeout, int state) | |
1da177e4 | 2753 | { |
1da177e4 LT |
2754 | might_sleep(); |
2755 | ||
2756 | spin_lock_irq(&x->wait.lock); | |
686855f5 | 2757 | timeout = do_wait_for_common(x, action, timeout, state); |
1da177e4 | 2758 | spin_unlock_irq(&x->wait.lock); |
8cbbe86d AK |
2759 | return timeout; |
2760 | } | |
1da177e4 | 2761 | |
686855f5 VD |
2762 | static long __sched |
2763 | wait_for_common(struct completion *x, long timeout, int state) | |
2764 | { | |
2765 | return __wait_for_common(x, schedule_timeout, timeout, state); | |
2766 | } | |
2767 | ||
2768 | static long __sched | |
2769 | wait_for_common_io(struct completion *x, long timeout, int state) | |
2770 | { | |
2771 | return __wait_for_common(x, io_schedule_timeout, timeout, state); | |
2772 | } | |
2773 | ||
65eb3dc6 KD |
2774 | /** |
2775 | * wait_for_completion: - waits for completion of a task | |
2776 | * @x: holds the state of this particular completion | |
2777 | * | |
2778 | * This waits to be signaled for completion of a specific task. It is NOT | |
2779 | * interruptible and there is no timeout. | |
2780 | * | |
2781 | * See also similar routines (i.e. wait_for_completion_timeout()) with timeout | |
2782 | * and interrupt capability. Also see complete(). | |
2783 | */ | |
b15136e9 | 2784 | void __sched wait_for_completion(struct completion *x) |
8cbbe86d AK |
2785 | { |
2786 | wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
1da177e4 | 2787 | } |
8cbbe86d | 2788 | EXPORT_SYMBOL(wait_for_completion); |
1da177e4 | 2789 | |
65eb3dc6 KD |
2790 | /** |
2791 | * wait_for_completion_timeout: - waits for completion of a task (w/timeout) | |
2792 | * @x: holds the state of this particular completion | |
2793 | * @timeout: timeout value in jiffies | |
2794 | * | |
2795 | * This waits for either a completion of a specific task to be signaled or for a | |
2796 | * specified timeout to expire. The timeout is in jiffies. It is not | |
2797 | * interruptible. | |
c6dc7f05 | 2798 | * |
e69f6186 YB |
2799 | * Return: 0 if timed out, and positive (at least 1, or number of jiffies left |
2800 | * till timeout) if completed. | |
65eb3dc6 | 2801 | */ |
b15136e9 | 2802 | unsigned long __sched |
8cbbe86d | 2803 | wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
1da177e4 | 2804 | { |
8cbbe86d | 2805 | return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
1da177e4 | 2806 | } |
8cbbe86d | 2807 | EXPORT_SYMBOL(wait_for_completion_timeout); |
1da177e4 | 2808 | |
686855f5 VD |
2809 | /** |
2810 | * wait_for_completion_io: - waits for completion of a task | |
2811 | * @x: holds the state of this particular completion | |
2812 | * | |
2813 | * This waits to be signaled for completion of a specific task. It is NOT | |
2814 | * interruptible and there is no timeout. The caller is accounted as waiting | |
2815 | * for IO. | |
2816 | */ | |
2817 | void __sched wait_for_completion_io(struct completion *x) | |
2818 | { | |
2819 | wait_for_common_io(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); | |
2820 | } | |
2821 | EXPORT_SYMBOL(wait_for_completion_io); | |
2822 | ||
2823 | /** | |
2824 | * wait_for_completion_io_timeout: - waits for completion of a task (w/timeout) | |
2825 | * @x: holds the state of this particular completion | |
2826 | * @timeout: timeout value in jiffies | |
2827 | * | |
2828 | * This waits for either a completion of a specific task to be signaled or for a | |
2829 | * specified timeout to expire. The timeout is in jiffies. It is not | |
2830 | * interruptible. The caller is accounted as waiting for IO. | |
2831 | * | |
e69f6186 YB |
2832 | * Return: 0 if timed out, and positive (at least 1, or number of jiffies left |
2833 | * till timeout) if completed. | |
686855f5 VD |
2834 | */ |
2835 | unsigned long __sched | |
2836 | wait_for_completion_io_timeout(struct completion *x, unsigned long timeout) | |
2837 | { | |
2838 | return wait_for_common_io(x, timeout, TASK_UNINTERRUPTIBLE); | |
2839 | } | |
2840 | EXPORT_SYMBOL(wait_for_completion_io_timeout); | |
2841 | ||
65eb3dc6 KD |
2842 | /** |
2843 | * wait_for_completion_interruptible: - waits for completion of a task (w/intr) | |
2844 | * @x: holds the state of this particular completion | |
2845 | * | |
2846 | * This waits for completion of a specific task to be signaled. It is | |
2847 | * interruptible. | |
c6dc7f05 | 2848 | * |
e69f6186 | 2849 | * Return: -ERESTARTSYS if interrupted, 0 if completed. |
65eb3dc6 | 2850 | */ |
8cbbe86d | 2851 | int __sched wait_for_completion_interruptible(struct completion *x) |
0fec171c | 2852 | { |
51e97990 AK |
2853 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
2854 | if (t == -ERESTARTSYS) | |
2855 | return t; | |
2856 | return 0; | |
0fec171c | 2857 | } |
8cbbe86d | 2858 | EXPORT_SYMBOL(wait_for_completion_interruptible); |
1da177e4 | 2859 | |
65eb3dc6 KD |
2860 | /** |
2861 | * wait_for_completion_interruptible_timeout: - waits for completion (w/(to,intr)) | |
2862 | * @x: holds the state of this particular completion | |
2863 | * @timeout: timeout value in jiffies | |
2864 | * | |
2865 | * This waits for either a completion of a specific task to be signaled or for a | |
2866 | * specified timeout to expire. It is interruptible. The timeout is in jiffies. | |
c6dc7f05 | 2867 | * |
e69f6186 YB |
2868 | * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1, |
2869 | * or number of jiffies left till timeout) if completed. | |
65eb3dc6 | 2870 | */ |
6bf41237 | 2871 | long __sched |
8cbbe86d AK |
2872 | wait_for_completion_interruptible_timeout(struct completion *x, |
2873 | unsigned long timeout) | |
0fec171c | 2874 | { |
8cbbe86d | 2875 | return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
0fec171c | 2876 | } |
8cbbe86d | 2877 | EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
1da177e4 | 2878 | |
65eb3dc6 KD |
2879 | /** |
2880 | * wait_for_completion_killable: - waits for completion of a task (killable) | |
2881 | * @x: holds the state of this particular completion | |
2882 | * | |
2883 | * This waits to be signaled for completion of a specific task. It can be | |
2884 | * interrupted by a kill signal. | |
c6dc7f05 | 2885 | * |
e69f6186 | 2886 | * Return: -ERESTARTSYS if interrupted, 0 if completed. |
65eb3dc6 | 2887 | */ |
009e577e MW |
2888 | int __sched wait_for_completion_killable(struct completion *x) |
2889 | { | |
2890 | long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); | |
2891 | if (t == -ERESTARTSYS) | |
2892 | return t; | |
2893 | return 0; | |
2894 | } | |
2895 | EXPORT_SYMBOL(wait_for_completion_killable); | |
2896 | ||
0aa12fb4 SW |
2897 | /** |
2898 | * wait_for_completion_killable_timeout: - waits for completion of a task (w/(to,killable)) | |
2899 | * @x: holds the state of this particular completion | |
2900 | * @timeout: timeout value in jiffies | |
2901 | * | |
2902 | * This waits for either a completion of a specific task to be | |
2903 | * signaled or for a specified timeout to expire. It can be | |
2904 | * interrupted by a kill signal. The timeout is in jiffies. | |
c6dc7f05 | 2905 | * |
e69f6186 YB |
2906 | * Return: -ERESTARTSYS if interrupted, 0 if timed out, positive (at least 1, |
2907 | * or number of jiffies left till timeout) if completed. | |
0aa12fb4 | 2908 | */ |
6bf41237 | 2909 | long __sched |
0aa12fb4 SW |
2910 | wait_for_completion_killable_timeout(struct completion *x, |
2911 | unsigned long timeout) | |
2912 | { | |
2913 | return wait_for_common(x, timeout, TASK_KILLABLE); | |
2914 | } | |
2915 | EXPORT_SYMBOL(wait_for_completion_killable_timeout); | |
2916 | ||
be4de352 DC |
2917 | /** |
2918 | * try_wait_for_completion - try to decrement a completion without blocking | |
2919 | * @x: completion structure | |
2920 | * | |
e69f6186 | 2921 | * Return: 0 if a decrement cannot be done without blocking |
be4de352 DC |
2922 | * 1 if a decrement succeeded. |
2923 | * | |
2924 | * If a completion is being used as a counting completion, | |
2925 | * attempt to decrement the counter without blocking. This | |
2926 | * enables us to avoid waiting if the resource the completion | |
2927 | * is protecting is not available. | |
2928 | */ | |
2929 | bool try_wait_for_completion(struct completion *x) | |
2930 | { | |
7539a3b3 | 2931 | unsigned long flags; |
be4de352 DC |
2932 | int ret = 1; |
2933 | ||
7539a3b3 | 2934 | spin_lock_irqsave(&x->wait.lock, flags); |
be4de352 DC |
2935 | if (!x->done) |
2936 | ret = 0; | |
2937 | else | |
2938 | x->done--; | |
7539a3b3 | 2939 | spin_unlock_irqrestore(&x->wait.lock, flags); |
be4de352 DC |
2940 | return ret; |
2941 | } | |
2942 | EXPORT_SYMBOL(try_wait_for_completion); | |
2943 | ||
2944 | /** | |
2945 | * completion_done - Test to see if a completion has any waiters | |
2946 | * @x: completion structure | |
2947 | * | |
e69f6186 | 2948 | * Return: 0 if there are waiters (wait_for_completion() in progress) |
be4de352 DC |
2949 | * 1 if there are no waiters. |
2950 | * | |
2951 | */ | |
2952 | bool completion_done(struct completion *x) | |
2953 | { | |
7539a3b3 | 2954 | unsigned long flags; |
be4de352 DC |
2955 | int ret = 1; |
2956 | ||
7539a3b3 | 2957 | spin_lock_irqsave(&x->wait.lock, flags); |
be4de352 DC |
2958 | if (!x->done) |
2959 | ret = 0; | |
7539a3b3 | 2960 | spin_unlock_irqrestore(&x->wait.lock, flags); |
be4de352 DC |
2961 | return ret; |
2962 | } | |
2963 | EXPORT_SYMBOL(completion_done); | |
2964 | ||
8cbbe86d AK |
2965 | static long __sched |
2966 | sleep_on_common(wait_queue_head_t *q, int state, long timeout) | |
1da177e4 | 2967 | { |
0fec171c IM |
2968 | unsigned long flags; |
2969 | wait_queue_t wait; | |
2970 | ||
2971 | init_waitqueue_entry(&wait, current); | |
1da177e4 | 2972 | |
8cbbe86d | 2973 | __set_current_state(state); |
1da177e4 | 2974 | |
8cbbe86d AK |
2975 | spin_lock_irqsave(&q->lock, flags); |
2976 | __add_wait_queue(q, &wait); | |
2977 | spin_unlock(&q->lock); | |
2978 | timeout = schedule_timeout(timeout); | |
2979 | spin_lock_irq(&q->lock); | |
2980 | __remove_wait_queue(q, &wait); | |
2981 | spin_unlock_irqrestore(&q->lock, flags); | |
2982 | ||
2983 | return timeout; | |
2984 | } | |
2985 | ||
2986 | void __sched interruptible_sleep_on(wait_queue_head_t *q) | |
2987 | { | |
2988 | sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); | |
1da177e4 | 2989 | } |
1da177e4 LT |
2990 | EXPORT_SYMBOL(interruptible_sleep_on); |
2991 | ||
0fec171c | 2992 | long __sched |
95cdf3b7 | 2993 | interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 2994 | { |
8cbbe86d | 2995 | return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
1da177e4 | 2996 | } |
1da177e4 LT |
2997 | EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
2998 | ||
0fec171c | 2999 | void __sched sleep_on(wait_queue_head_t *q) |
1da177e4 | 3000 | { |
8cbbe86d | 3001 | sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
1da177e4 | 3002 | } |
1da177e4 LT |
3003 | EXPORT_SYMBOL(sleep_on); |
3004 | ||
0fec171c | 3005 | long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
1da177e4 | 3006 | { |
8cbbe86d | 3007 | return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
1da177e4 | 3008 | } |
1da177e4 LT |
3009 | EXPORT_SYMBOL(sleep_on_timeout); |
3010 | ||
b29739f9 IM |
3011 | #ifdef CONFIG_RT_MUTEXES |
3012 | ||
3013 | /* | |
3014 | * rt_mutex_setprio - set the current priority of a task | |
3015 | * @p: task | |
3016 | * @prio: prio value (kernel-internal form) | |
3017 | * | |
3018 | * This function changes the 'effective' priority of a task. It does | |
3019 | * not touch ->normal_prio like __setscheduler(). | |
3020 | * | |
3021 | * Used by the rt_mutex code to implement priority inheritance logic. | |
3022 | */ | |
36c8b586 | 3023 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 | 3024 | { |
83b699ed | 3025 | int oldprio, on_rq, running; |
70b97a7f | 3026 | struct rq *rq; |
83ab0aa0 | 3027 | const struct sched_class *prev_class; |
b29739f9 IM |
3028 | |
3029 | BUG_ON(prio < 0 || prio > MAX_PRIO); | |
3030 | ||
0122ec5b | 3031 | rq = __task_rq_lock(p); |
b29739f9 | 3032 | |
1c4dd99b TG |
3033 | /* |
3034 | * Idle task boosting is a nono in general. There is one | |
3035 | * exception, when PREEMPT_RT and NOHZ is active: | |
3036 | * | |
3037 | * The idle task calls get_next_timer_interrupt() and holds | |
3038 | * the timer wheel base->lock on the CPU and another CPU wants | |
3039 | * to access the timer (probably to cancel it). We can safely | |
3040 | * ignore the boosting request, as the idle CPU runs this code | |
3041 | * with interrupts disabled and will complete the lock | |
3042 | * protected section without being interrupted. So there is no | |
3043 | * real need to boost. | |
3044 | */ | |
3045 | if (unlikely(p == rq->idle)) { | |
3046 | WARN_ON(p != rq->curr); | |
3047 | WARN_ON(p->pi_blocked_on); | |
3048 | goto out_unlock; | |
3049 | } | |
3050 | ||
a8027073 | 3051 | trace_sched_pi_setprio(p, prio); |
d5f9f942 | 3052 | oldprio = p->prio; |
83ab0aa0 | 3053 | prev_class = p->sched_class; |
fd2f4419 | 3054 | on_rq = p->on_rq; |
051a1d1a | 3055 | running = task_current(rq, p); |
0e1f3483 | 3056 | if (on_rq) |
69be72c1 | 3057 | dequeue_task(rq, p, 0); |
0e1f3483 HS |
3058 | if (running) |
3059 | p->sched_class->put_prev_task(rq, p); | |
dd41f596 IM |
3060 | |
3061 | if (rt_prio(prio)) | |
3062 | p->sched_class = &rt_sched_class; | |
3063 | else | |
3064 | p->sched_class = &fair_sched_class; | |
3065 | ||
b29739f9 IM |
3066 | p->prio = prio; |
3067 | ||
0e1f3483 HS |
3068 | if (running) |
3069 | p->sched_class->set_curr_task(rq); | |
da7a735e | 3070 | if (on_rq) |
371fd7e7 | 3071 | enqueue_task(rq, p, oldprio < prio ? ENQUEUE_HEAD : 0); |
cb469845 | 3072 | |
da7a735e | 3073 | check_class_changed(rq, p, prev_class, oldprio); |
1c4dd99b | 3074 | out_unlock: |
0122ec5b | 3075 | __task_rq_unlock(rq); |
b29739f9 | 3076 | } |
b29739f9 | 3077 | #endif |
36c8b586 | 3078 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3079 | { |
dd41f596 | 3080 | int old_prio, delta, on_rq; |
1da177e4 | 3081 | unsigned long flags; |
70b97a7f | 3082 | struct rq *rq; |
1da177e4 LT |
3083 | |
3084 | if (TASK_NICE(p) == nice || nice < -20 || nice > 19) | |
3085 | return; | |
3086 | /* | |
3087 | * We have to be careful, if called from sys_setpriority(), | |
3088 | * the task might be in the middle of scheduling on another CPU. | |
3089 | */ | |
3090 | rq = task_rq_lock(p, &flags); | |
3091 | /* | |
3092 | * The RT priorities are set via sched_setscheduler(), but we still | |
3093 | * allow the 'normal' nice value to be set - but as expected | |
3094 | * it wont have any effect on scheduling until the task is | |
dd41f596 | 3095 | * SCHED_FIFO/SCHED_RR: |
1da177e4 | 3096 | */ |
e05606d3 | 3097 | if (task_has_rt_policy(p)) { |
1da177e4 LT |
3098 | p->static_prio = NICE_TO_PRIO(nice); |
3099 | goto out_unlock; | |
3100 | } | |
fd2f4419 | 3101 | on_rq = p->on_rq; |
c09595f6 | 3102 | if (on_rq) |
69be72c1 | 3103 | dequeue_task(rq, p, 0); |
1da177e4 | 3104 | |
1da177e4 | 3105 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3106 | set_load_weight(p); |
b29739f9 IM |
3107 | old_prio = p->prio; |
3108 | p->prio = effective_prio(p); | |
3109 | delta = p->prio - old_prio; | |
1da177e4 | 3110 | |
dd41f596 | 3111 | if (on_rq) { |
371fd7e7 | 3112 | enqueue_task(rq, p, 0); |
1da177e4 | 3113 | /* |
d5f9f942 AM |
3114 | * If the task increased its priority or is running and |
3115 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3116 | */ |
d5f9f942 | 3117 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
1da177e4 LT |
3118 | resched_task(rq->curr); |
3119 | } | |
3120 | out_unlock: | |
0122ec5b | 3121 | task_rq_unlock(rq, p, &flags); |
1da177e4 | 3122 | } |
1da177e4 LT |
3123 | EXPORT_SYMBOL(set_user_nice); |
3124 | ||
e43379f1 MM |
3125 | /* |
3126 | * can_nice - check if a task can reduce its nice value | |
3127 | * @p: task | |
3128 | * @nice: nice value | |
3129 | */ | |
36c8b586 | 3130 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3131 | { |
024f4747 MM |
3132 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
3133 | int nice_rlim = 20 - nice; | |
48f24c4d | 3134 | |
78d7d407 | 3135 | return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || |
e43379f1 MM |
3136 | capable(CAP_SYS_NICE)); |
3137 | } | |
3138 | ||
1da177e4 LT |
3139 | #ifdef __ARCH_WANT_SYS_NICE |
3140 | ||
3141 | /* | |
3142 | * sys_nice - change the priority of the current process. | |
3143 | * @increment: priority increment | |
3144 | * | |
3145 | * sys_setpriority is a more generic, but much slower function that | |
3146 | * does similar things. | |
3147 | */ | |
5add95d4 | 3148 | SYSCALL_DEFINE1(nice, int, increment) |
1da177e4 | 3149 | { |
48f24c4d | 3150 | long nice, retval; |
1da177e4 LT |
3151 | |
3152 | /* | |
3153 | * Setpriority might change our priority at the same moment. | |
3154 | * We don't have to worry. Conceptually one call occurs first | |
3155 | * and we have a single winner. | |
3156 | */ | |
e43379f1 MM |
3157 | if (increment < -40) |
3158 | increment = -40; | |
1da177e4 LT |
3159 | if (increment > 40) |
3160 | increment = 40; | |
3161 | ||
2b8f836f | 3162 | nice = TASK_NICE(current) + increment; |
1da177e4 LT |
3163 | if (nice < -20) |
3164 | nice = -20; | |
3165 | if (nice > 19) | |
3166 | nice = 19; | |
3167 | ||
e43379f1 MM |
3168 | if (increment < 0 && !can_nice(current, nice)) |
3169 | return -EPERM; | |
3170 | ||
1da177e4 LT |
3171 | retval = security_task_setnice(current, nice); |
3172 | if (retval) | |
3173 | return retval; | |
3174 | ||
3175 | set_user_nice(current, nice); | |
3176 | return 0; | |
3177 | } | |
3178 | ||
3179 | #endif | |
3180 | ||
3181 | /** | |
3182 | * task_prio - return the priority value of a given task. | |
3183 | * @p: the task in question. | |
3184 | * | |
e69f6186 | 3185 | * Return: The priority value as seen by users in /proc. |
1da177e4 LT |
3186 | * RT tasks are offset by -200. Normal tasks are centered |
3187 | * around 0, value goes from -16 to +15. | |
3188 | */ | |
36c8b586 | 3189 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
3190 | { |
3191 | return p->prio - MAX_RT_PRIO; | |
3192 | } | |
3193 | ||
3194 | /** | |
3195 | * task_nice - return the nice value of a given task. | |
3196 | * @p: the task in question. | |
e69f6186 YB |
3197 | * |
3198 | * Return: The nice value [ -20 ... 0 ... 19 ]. | |
1da177e4 | 3199 | */ |
36c8b586 | 3200 | int task_nice(const struct task_struct *p) |
1da177e4 LT |
3201 | { |
3202 | return TASK_NICE(p); | |
3203 | } | |
150d8bed | 3204 | EXPORT_SYMBOL(task_nice); |
1da177e4 LT |
3205 | |
3206 | /** | |
3207 | * idle_cpu - is a given cpu idle currently? | |
3208 | * @cpu: the processor in question. | |
e69f6186 YB |
3209 | * |
3210 | * Return: 1 if the CPU is currently idle. 0 otherwise. | |
1da177e4 LT |
3211 | */ |
3212 | int idle_cpu(int cpu) | |
3213 | { | |
908a3283 TG |
3214 | struct rq *rq = cpu_rq(cpu); |
3215 | ||
3216 | if (rq->curr != rq->idle) | |
3217 | return 0; | |
3218 | ||
3219 | if (rq->nr_running) | |
3220 | return 0; | |
3221 | ||
3222 | #ifdef CONFIG_SMP | |
3223 | if (!llist_empty(&rq->wake_list)) | |
3224 | return 0; | |
3225 | #endif | |
3226 | ||
3227 | return 1; | |
1da177e4 LT |
3228 | } |
3229 | ||
1da177e4 LT |
3230 | /** |
3231 | * idle_task - return the idle task for a given cpu. | |
3232 | * @cpu: the processor in question. | |
e69f6186 YB |
3233 | * |
3234 | * Return: The idle task for the cpu @cpu. | |
1da177e4 | 3235 | */ |
36c8b586 | 3236 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
3237 | { |
3238 | return cpu_rq(cpu)->idle; | |
3239 | } | |
3240 | ||
3241 | /** | |
3242 | * find_process_by_pid - find a process with a matching PID value. | |
3243 | * @pid: the pid in question. | |
e69f6186 YB |
3244 | * |
3245 | * The task of @pid, if found. %NULL otherwise. | |
1da177e4 | 3246 | */ |
a9957449 | 3247 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 3248 | { |
228ebcbe | 3249 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
3250 | } |
3251 | ||
3252 | /* Actually do priority change: must hold rq lock. */ | |
dd41f596 IM |
3253 | static void |
3254 | __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) | |
1da177e4 | 3255 | { |
1da177e4 LT |
3256 | p->policy = policy; |
3257 | p->rt_priority = prio; | |
b29739f9 IM |
3258 | p->normal_prio = normal_prio(p); |
3259 | /* we are holding p->pi_lock already */ | |
3260 | p->prio = rt_mutex_getprio(p); | |
ffd44db5 PZ |
3261 | if (rt_prio(p->prio)) |
3262 | p->sched_class = &rt_sched_class; | |
3263 | else | |
3264 | p->sched_class = &fair_sched_class; | |
2dd73a4f | 3265 | set_load_weight(p); |
1da177e4 LT |
3266 | } |
3267 | ||
c69e8d9c DH |
3268 | /* |
3269 | * check the target process has a UID that matches the current process's | |
3270 | */ | |
3271 | static bool check_same_owner(struct task_struct *p) | |
3272 | { | |
3273 | const struct cred *cred = current_cred(), *pcred; | |
3274 | bool match; | |
3275 | ||
3276 | rcu_read_lock(); | |
3277 | pcred = __task_cred(p); | |
9c806aa0 EB |
3278 | match = (uid_eq(cred->euid, pcred->euid) || |
3279 | uid_eq(cred->euid, pcred->uid)); | |
c69e8d9c DH |
3280 | rcu_read_unlock(); |
3281 | return match; | |
3282 | } | |
3283 | ||
961ccddd | 3284 | static int __sched_setscheduler(struct task_struct *p, int policy, |
fe7de49f | 3285 | const struct sched_param *param, bool user) |
1da177e4 | 3286 | { |
83b699ed | 3287 | int retval, oldprio, oldpolicy = -1, on_rq, running; |
1da177e4 | 3288 | unsigned long flags; |
83ab0aa0 | 3289 | const struct sched_class *prev_class; |
70b97a7f | 3290 | struct rq *rq; |
ca94c442 | 3291 | int reset_on_fork; |
1da177e4 | 3292 | |
66e5393a SR |
3293 | /* may grab non-irq protected spin_locks */ |
3294 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
3295 | recheck: |
3296 | /* double check policy once rq lock held */ | |
ca94c442 LP |
3297 | if (policy < 0) { |
3298 | reset_on_fork = p->sched_reset_on_fork; | |
1da177e4 | 3299 | policy = oldpolicy = p->policy; |
ca94c442 LP |
3300 | } else { |
3301 | reset_on_fork = !!(policy & SCHED_RESET_ON_FORK); | |
3302 | policy &= ~SCHED_RESET_ON_FORK; | |
3303 | ||
3304 | if (policy != SCHED_FIFO && policy != SCHED_RR && | |
3305 | policy != SCHED_NORMAL && policy != SCHED_BATCH && | |
3306 | policy != SCHED_IDLE) | |
3307 | return -EINVAL; | |
3308 | } | |
3309 | ||
1da177e4 LT |
3310 | /* |
3311 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
3312 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
3313 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 LT |
3314 | */ |
3315 | if (param->sched_priority < 0 || | |
95cdf3b7 | 3316 | (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
d46523ea | 3317 | (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 3318 | return -EINVAL; |
e05606d3 | 3319 | if (rt_policy(policy) != (param->sched_priority != 0)) |
1da177e4 LT |
3320 | return -EINVAL; |
3321 | ||
37e4ab3f OC |
3322 | /* |
3323 | * Allow unprivileged RT tasks to decrease priority: | |
3324 | */ | |
961ccddd | 3325 | if (user && !capable(CAP_SYS_NICE)) { |
e05606d3 | 3326 | if (rt_policy(policy)) { |
a44702e8 ON |
3327 | unsigned long rlim_rtprio = |
3328 | task_rlimit(p, RLIMIT_RTPRIO); | |
8dc3e909 ON |
3329 | |
3330 | /* can't set/change the rt policy */ | |
3331 | if (policy != p->policy && !rlim_rtprio) | |
3332 | return -EPERM; | |
3333 | ||
3334 | /* can't increase priority */ | |
3335 | if (param->sched_priority > p->rt_priority && | |
3336 | param->sched_priority > rlim_rtprio) | |
3337 | return -EPERM; | |
3338 | } | |
c02aa73b | 3339 | |
dd41f596 | 3340 | /* |
c02aa73b DH |
3341 | * Treat SCHED_IDLE as nice 20. Only allow a switch to |
3342 | * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. | |
dd41f596 | 3343 | */ |
c02aa73b DH |
3344 | if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) { |
3345 | if (!can_nice(p, TASK_NICE(p))) | |
3346 | return -EPERM; | |
3347 | } | |
5fe1d75f | 3348 | |
37e4ab3f | 3349 | /* can't change other user's priorities */ |
c69e8d9c | 3350 | if (!check_same_owner(p)) |
37e4ab3f | 3351 | return -EPERM; |
ca94c442 LP |
3352 | |
3353 | /* Normal users shall not reset the sched_reset_on_fork flag */ | |
3354 | if (p->sched_reset_on_fork && !reset_on_fork) | |
3355 | return -EPERM; | |
37e4ab3f | 3356 | } |
1da177e4 | 3357 | |
725aad24 | 3358 | if (user) { |
b0ae1981 | 3359 | retval = security_task_setscheduler(p); |
725aad24 JF |
3360 | if (retval) |
3361 | return retval; | |
3362 | } | |
3363 | ||
b29739f9 IM |
3364 | /* |
3365 | * make sure no PI-waiters arrive (or leave) while we are | |
3366 | * changing the priority of the task: | |
0122ec5b | 3367 | * |
25985edc | 3368 | * To be able to change p->policy safely, the appropriate |
1da177e4 LT |
3369 | * runqueue lock must be held. |
3370 | */ | |
0122ec5b | 3371 | rq = task_rq_lock(p, &flags); |
dc61b1d6 | 3372 | |
34f971f6 PZ |
3373 | /* |
3374 | * Changing the policy of the stop threads its a very bad idea | |
3375 | */ | |
3376 | if (p == rq->stop) { | |
0122ec5b | 3377 | task_rq_unlock(rq, p, &flags); |
34f971f6 PZ |
3378 | return -EINVAL; |
3379 | } | |
3380 | ||
a51e9198 DF |
3381 | /* |
3382 | * If not changing anything there's no need to proceed further: | |
3383 | */ | |
3384 | if (unlikely(policy == p->policy && (!rt_policy(policy) || | |
3385 | param->sched_priority == p->rt_priority))) { | |
45afb173 | 3386 | task_rq_unlock(rq, p, &flags); |
a51e9198 DF |
3387 | return 0; |
3388 | } | |
3389 | ||
dc61b1d6 PZ |
3390 | #ifdef CONFIG_RT_GROUP_SCHED |
3391 | if (user) { | |
3392 | /* | |
3393 | * Do not allow realtime tasks into groups that have no runtime | |
3394 | * assigned. | |
3395 | */ | |
3396 | if (rt_bandwidth_enabled() && rt_policy(policy) && | |
f4493771 MG |
3397 | task_group(p)->rt_bandwidth.rt_runtime == 0 && |
3398 | !task_group_is_autogroup(task_group(p))) { | |
0122ec5b | 3399 | task_rq_unlock(rq, p, &flags); |
dc61b1d6 PZ |
3400 | return -EPERM; |
3401 | } | |
3402 | } | |
3403 | #endif | |
3404 | ||
1da177e4 LT |
3405 | /* recheck policy now with rq lock held */ |
3406 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
3407 | policy = oldpolicy = -1; | |
0122ec5b | 3408 | task_rq_unlock(rq, p, &flags); |
1da177e4 LT |
3409 | goto recheck; |
3410 | } | |
fd2f4419 | 3411 | on_rq = p->on_rq; |
051a1d1a | 3412 | running = task_current(rq, p); |
0e1f3483 | 3413 | if (on_rq) |
4ca9b72b | 3414 | dequeue_task(rq, p, 0); |
0e1f3483 HS |
3415 | if (running) |
3416 | p->sched_class->put_prev_task(rq, p); | |
f6b53205 | 3417 | |
ca94c442 LP |
3418 | p->sched_reset_on_fork = reset_on_fork; |
3419 | ||
1da177e4 | 3420 | oldprio = p->prio; |
83ab0aa0 | 3421 | prev_class = p->sched_class; |
dd41f596 | 3422 | __setscheduler(rq, p, policy, param->sched_priority); |
f6b53205 | 3423 | |
0e1f3483 HS |
3424 | if (running) |
3425 | p->sched_class->set_curr_task(rq); | |
da7a735e | 3426 | if (on_rq) |
4ca9b72b | 3427 | enqueue_task(rq, p, 0); |
cb469845 | 3428 | |
da7a735e | 3429 | check_class_changed(rq, p, prev_class, oldprio); |
0122ec5b | 3430 | task_rq_unlock(rq, p, &flags); |
b29739f9 | 3431 | |
95e02ca9 TG |
3432 | rt_mutex_adjust_pi(p); |
3433 | ||
1da177e4 LT |
3434 | return 0; |
3435 | } | |
961ccddd RR |
3436 | |
3437 | /** | |
3438 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. | |
3439 | * @p: the task in question. | |
3440 | * @policy: new policy. | |
3441 | * @param: structure containing the new RT priority. | |
3442 | * | |
e69f6186 YB |
3443 | * Return: 0 on success. An error code otherwise. |
3444 | * | |
961ccddd RR |
3445 | * NOTE that the task may be already dead. |
3446 | */ | |
3447 | int sched_setscheduler(struct task_struct *p, int policy, | |
fe7de49f | 3448 | const struct sched_param *param) |
961ccddd RR |
3449 | { |
3450 | return __sched_setscheduler(p, policy, param, true); | |
3451 | } | |
1da177e4 LT |
3452 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
3453 | ||
961ccddd RR |
3454 | /** |
3455 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. | |
3456 | * @p: the task in question. | |
3457 | * @policy: new policy. | |
3458 | * @param: structure containing the new RT priority. | |
3459 | * | |
3460 | * Just like sched_setscheduler, only don't bother checking if the | |
3461 | * current context has permission. For example, this is needed in | |
3462 | * stop_machine(): we create temporary high priority worker threads, | |
3463 | * but our caller might not have that capability. | |
e69f6186 YB |
3464 | * |
3465 | * Return: 0 on success. An error code otherwise. | |
961ccddd RR |
3466 | */ |
3467 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, | |
fe7de49f | 3468 | const struct sched_param *param) |
961ccddd RR |
3469 | { |
3470 | return __sched_setscheduler(p, policy, param, false); | |
3471 | } | |
3472 | ||
95cdf3b7 IM |
3473 | static int |
3474 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 3475 | { |
1da177e4 LT |
3476 | struct sched_param lparam; |
3477 | struct task_struct *p; | |
36c8b586 | 3478 | int retval; |
1da177e4 LT |
3479 | |
3480 | if (!param || pid < 0) | |
3481 | return -EINVAL; | |
3482 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
3483 | return -EFAULT; | |
5fe1d75f ON |
3484 | |
3485 | rcu_read_lock(); | |
3486 | retval = -ESRCH; | |
1da177e4 | 3487 | p = find_process_by_pid(pid); |
5fe1d75f ON |
3488 | if (p != NULL) |
3489 | retval = sched_setscheduler(p, policy, &lparam); | |
3490 | rcu_read_unlock(); | |
36c8b586 | 3491 | |
1da177e4 LT |
3492 | return retval; |
3493 | } | |
3494 | ||
3495 | /** | |
3496 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
3497 | * @pid: the pid in question. | |
3498 | * @policy: new policy. | |
3499 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
3500 | * |
3501 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 3502 | */ |
5add95d4 HC |
3503 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
3504 | struct sched_param __user *, param) | |
1da177e4 | 3505 | { |
c21761f1 JB |
3506 | /* negative values for policy are not valid */ |
3507 | if (policy < 0) | |
3508 | return -EINVAL; | |
3509 | ||
1da177e4 LT |
3510 | return do_sched_setscheduler(pid, policy, param); |
3511 | } | |
3512 | ||
3513 | /** | |
3514 | * sys_sched_setparam - set/change the RT priority of a thread | |
3515 | * @pid: the pid in question. | |
3516 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
3517 | * |
3518 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 3519 | */ |
5add95d4 | 3520 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 LT |
3521 | { |
3522 | return do_sched_setscheduler(pid, -1, param); | |
3523 | } | |
3524 | ||
3525 | /** | |
3526 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
3527 | * @pid: the pid in question. | |
e69f6186 YB |
3528 | * |
3529 | * Return: On success, the policy of the thread. Otherwise, a negative error | |
3530 | * code. | |
1da177e4 | 3531 | */ |
5add95d4 | 3532 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
1da177e4 | 3533 | { |
36c8b586 | 3534 | struct task_struct *p; |
3a5c359a | 3535 | int retval; |
1da177e4 LT |
3536 | |
3537 | if (pid < 0) | |
3a5c359a | 3538 | return -EINVAL; |
1da177e4 LT |
3539 | |
3540 | retval = -ESRCH; | |
5fe85be0 | 3541 | rcu_read_lock(); |
1da177e4 LT |
3542 | p = find_process_by_pid(pid); |
3543 | if (p) { | |
3544 | retval = security_task_getscheduler(p); | |
3545 | if (!retval) | |
ca94c442 LP |
3546 | retval = p->policy |
3547 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); | |
1da177e4 | 3548 | } |
5fe85be0 | 3549 | rcu_read_unlock(); |
1da177e4 LT |
3550 | return retval; |
3551 | } | |
3552 | ||
3553 | /** | |
ca94c442 | 3554 | * sys_sched_getparam - get the RT priority of a thread |
1da177e4 LT |
3555 | * @pid: the pid in question. |
3556 | * @param: structure containing the RT priority. | |
e69f6186 YB |
3557 | * |
3558 | * Return: On success, 0 and the RT priority is in @param. Otherwise, an error | |
3559 | * code. | |
1da177e4 | 3560 | */ |
5add95d4 | 3561 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 LT |
3562 | { |
3563 | struct sched_param lp; | |
36c8b586 | 3564 | struct task_struct *p; |
3a5c359a | 3565 | int retval; |
1da177e4 LT |
3566 | |
3567 | if (!param || pid < 0) | |
3a5c359a | 3568 | return -EINVAL; |
1da177e4 | 3569 | |
5fe85be0 | 3570 | rcu_read_lock(); |
1da177e4 LT |
3571 | p = find_process_by_pid(pid); |
3572 | retval = -ESRCH; | |
3573 | if (!p) | |
3574 | goto out_unlock; | |
3575 | ||
3576 | retval = security_task_getscheduler(p); | |
3577 | if (retval) | |
3578 | goto out_unlock; | |
3579 | ||
3580 | lp.sched_priority = p->rt_priority; | |
5fe85be0 | 3581 | rcu_read_unlock(); |
1da177e4 LT |
3582 | |
3583 | /* | |
3584 | * This one might sleep, we cannot do it with a spinlock held ... | |
3585 | */ | |
3586 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
3587 | ||
1da177e4 LT |
3588 | return retval; |
3589 | ||
3590 | out_unlock: | |
5fe85be0 | 3591 | rcu_read_unlock(); |
1da177e4 LT |
3592 | return retval; |
3593 | } | |
3594 | ||
96f874e2 | 3595 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
1da177e4 | 3596 | { |
5a16f3d3 | 3597 | cpumask_var_t cpus_allowed, new_mask; |
36c8b586 IM |
3598 | struct task_struct *p; |
3599 | int retval; | |
1da177e4 | 3600 | |
95402b38 | 3601 | get_online_cpus(); |
23f5d142 | 3602 | rcu_read_lock(); |
1da177e4 LT |
3603 | |
3604 | p = find_process_by_pid(pid); | |
3605 | if (!p) { | |
23f5d142 | 3606 | rcu_read_unlock(); |
95402b38 | 3607 | put_online_cpus(); |
1da177e4 LT |
3608 | return -ESRCH; |
3609 | } | |
3610 | ||
23f5d142 | 3611 | /* Prevent p going away */ |
1da177e4 | 3612 | get_task_struct(p); |
23f5d142 | 3613 | rcu_read_unlock(); |
1da177e4 | 3614 | |
14a40ffc TH |
3615 | if (p->flags & PF_NO_SETAFFINITY) { |
3616 | retval = -EINVAL; | |
3617 | goto out_put_task; | |
3618 | } | |
5a16f3d3 RR |
3619 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
3620 | retval = -ENOMEM; | |
3621 | goto out_put_task; | |
3622 | } | |
3623 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { | |
3624 | retval = -ENOMEM; | |
3625 | goto out_free_cpus_allowed; | |
3626 | } | |
1da177e4 | 3627 | retval = -EPERM; |
4c44aaaf EB |
3628 | if (!check_same_owner(p)) { |
3629 | rcu_read_lock(); | |
3630 | if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { | |
3631 | rcu_read_unlock(); | |
3632 | goto out_unlock; | |
3633 | } | |
3634 | rcu_read_unlock(); | |
3635 | } | |
1da177e4 | 3636 | |
b0ae1981 | 3637 | retval = security_task_setscheduler(p); |
e7834f8f DQ |
3638 | if (retval) |
3639 | goto out_unlock; | |
3640 | ||
5a16f3d3 RR |
3641 | cpuset_cpus_allowed(p, cpus_allowed); |
3642 | cpumask_and(new_mask, in_mask, cpus_allowed); | |
49246274 | 3643 | again: |
5a16f3d3 | 3644 | retval = set_cpus_allowed_ptr(p, new_mask); |
1da177e4 | 3645 | |
8707d8b8 | 3646 | if (!retval) { |
5a16f3d3 RR |
3647 | cpuset_cpus_allowed(p, cpus_allowed); |
3648 | if (!cpumask_subset(new_mask, cpus_allowed)) { | |
8707d8b8 PM |
3649 | /* |
3650 | * We must have raced with a concurrent cpuset | |
3651 | * update. Just reset the cpus_allowed to the | |
3652 | * cpuset's cpus_allowed | |
3653 | */ | |
5a16f3d3 | 3654 | cpumask_copy(new_mask, cpus_allowed); |
8707d8b8 PM |
3655 | goto again; |
3656 | } | |
3657 | } | |
1da177e4 | 3658 | out_unlock: |
5a16f3d3 RR |
3659 | free_cpumask_var(new_mask); |
3660 | out_free_cpus_allowed: | |
3661 | free_cpumask_var(cpus_allowed); | |
3662 | out_put_task: | |
1da177e4 | 3663 | put_task_struct(p); |
95402b38 | 3664 | put_online_cpus(); |
1da177e4 LT |
3665 | return retval; |
3666 | } | |
3667 | ||
3668 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
96f874e2 | 3669 | struct cpumask *new_mask) |
1da177e4 | 3670 | { |
96f874e2 RR |
3671 | if (len < cpumask_size()) |
3672 | cpumask_clear(new_mask); | |
3673 | else if (len > cpumask_size()) | |
3674 | len = cpumask_size(); | |
3675 | ||
1da177e4 LT |
3676 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
3677 | } | |
3678 | ||
3679 | /** | |
3680 | * sys_sched_setaffinity - set the cpu affinity of a process | |
3681 | * @pid: pid of the process | |
3682 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
3683 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
e69f6186 YB |
3684 | * |
3685 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 3686 | */ |
5add95d4 HC |
3687 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
3688 | unsigned long __user *, user_mask_ptr) | |
1da177e4 | 3689 | { |
5a16f3d3 | 3690 | cpumask_var_t new_mask; |
1da177e4 LT |
3691 | int retval; |
3692 | ||
5a16f3d3 RR |
3693 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
3694 | return -ENOMEM; | |
1da177e4 | 3695 | |
5a16f3d3 RR |
3696 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
3697 | if (retval == 0) | |
3698 | retval = sched_setaffinity(pid, new_mask); | |
3699 | free_cpumask_var(new_mask); | |
3700 | return retval; | |
1da177e4 LT |
3701 | } |
3702 | ||
96f874e2 | 3703 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
1da177e4 | 3704 | { |
36c8b586 | 3705 | struct task_struct *p; |
31605683 | 3706 | unsigned long flags; |
1da177e4 | 3707 | int retval; |
1da177e4 | 3708 | |
95402b38 | 3709 | get_online_cpus(); |
23f5d142 | 3710 | rcu_read_lock(); |
1da177e4 LT |
3711 | |
3712 | retval = -ESRCH; | |
3713 | p = find_process_by_pid(pid); | |
3714 | if (!p) | |
3715 | goto out_unlock; | |
3716 | ||
e7834f8f DQ |
3717 | retval = security_task_getscheduler(p); |
3718 | if (retval) | |
3719 | goto out_unlock; | |
3720 | ||
013fdb80 | 3721 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
96f874e2 | 3722 | cpumask_and(mask, &p->cpus_allowed, cpu_online_mask); |
013fdb80 | 3723 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
3724 | |
3725 | out_unlock: | |
23f5d142 | 3726 | rcu_read_unlock(); |
95402b38 | 3727 | put_online_cpus(); |
1da177e4 | 3728 | |
9531b62f | 3729 | return retval; |
1da177e4 LT |
3730 | } |
3731 | ||
3732 | /** | |
3733 | * sys_sched_getaffinity - get the cpu affinity of a process | |
3734 | * @pid: pid of the process | |
3735 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
3736 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
e69f6186 YB |
3737 | * |
3738 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 3739 | */ |
5add95d4 HC |
3740 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
3741 | unsigned long __user *, user_mask_ptr) | |
1da177e4 LT |
3742 | { |
3743 | int ret; | |
f17c8607 | 3744 | cpumask_var_t mask; |
1da177e4 | 3745 | |
84fba5ec | 3746 | if ((len * BITS_PER_BYTE) < nr_cpu_ids) |
cd3d8031 KM |
3747 | return -EINVAL; |
3748 | if (len & (sizeof(unsigned long)-1)) | |
1da177e4 LT |
3749 | return -EINVAL; |
3750 | ||
f17c8607 RR |
3751 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
3752 | return -ENOMEM; | |
1da177e4 | 3753 | |
f17c8607 RR |
3754 | ret = sched_getaffinity(pid, mask); |
3755 | if (ret == 0) { | |
8bc037fb | 3756 | size_t retlen = min_t(size_t, len, cpumask_size()); |
cd3d8031 KM |
3757 | |
3758 | if (copy_to_user(user_mask_ptr, mask, retlen)) | |
f17c8607 RR |
3759 | ret = -EFAULT; |
3760 | else | |
cd3d8031 | 3761 | ret = retlen; |
f17c8607 RR |
3762 | } |
3763 | free_cpumask_var(mask); | |
1da177e4 | 3764 | |
f17c8607 | 3765 | return ret; |
1da177e4 LT |
3766 | } |
3767 | ||
3768 | /** | |
3769 | * sys_sched_yield - yield the current processor to other threads. | |
3770 | * | |
dd41f596 IM |
3771 | * This function yields the current CPU to other tasks. If there are no |
3772 | * other threads running on this CPU then this function will return. | |
e69f6186 YB |
3773 | * |
3774 | * Return: 0. | |
1da177e4 | 3775 | */ |
5add95d4 | 3776 | SYSCALL_DEFINE0(sched_yield) |
1da177e4 | 3777 | { |
70b97a7f | 3778 | struct rq *rq = this_rq_lock(); |
1da177e4 | 3779 | |
2d72376b | 3780 | schedstat_inc(rq, yld_count); |
4530d7ab | 3781 | current->sched_class->yield_task(rq); |
1da177e4 LT |
3782 | |
3783 | /* | |
3784 | * Since we are going to call schedule() anyway, there's | |
3785 | * no need to preempt or enable interrupts: | |
3786 | */ | |
3787 | __release(rq->lock); | |
8a25d5de | 3788 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
9828ea9d | 3789 | do_raw_spin_unlock(&rq->lock); |
ba74c144 | 3790 | sched_preempt_enable_no_resched(); |
1da177e4 LT |
3791 | |
3792 | schedule(); | |
3793 | ||
3794 | return 0; | |
3795 | } | |
3796 | ||
d86ee480 PZ |
3797 | static inline int should_resched(void) |
3798 | { | |
3799 | return need_resched() && !(preempt_count() & PREEMPT_ACTIVE); | |
3800 | } | |
3801 | ||
e7b38404 | 3802 | static void __cond_resched(void) |
1da177e4 | 3803 | { |
e7aaaa69 | 3804 | add_preempt_count(PREEMPT_ACTIVE); |
c259e01a | 3805 | __schedule(); |
e7aaaa69 | 3806 | sub_preempt_count(PREEMPT_ACTIVE); |
1da177e4 LT |
3807 | } |
3808 | ||
02b67cc3 | 3809 | int __sched _cond_resched(void) |
1da177e4 | 3810 | { |
d86ee480 | 3811 | if (should_resched()) { |
1da177e4 LT |
3812 | __cond_resched(); |
3813 | return 1; | |
3814 | } | |
3815 | return 0; | |
3816 | } | |
02b67cc3 | 3817 | EXPORT_SYMBOL(_cond_resched); |
1da177e4 LT |
3818 | |
3819 | /* | |
613afbf8 | 3820 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
1da177e4 LT |
3821 | * call schedule, and on return reacquire the lock. |
3822 | * | |
41a2d6cf | 3823 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
3824 | * operations here to prevent schedule() from being called twice (once via |
3825 | * spin_unlock(), once by hand). | |
3826 | */ | |
613afbf8 | 3827 | int __cond_resched_lock(spinlock_t *lock) |
1da177e4 | 3828 | { |
d86ee480 | 3829 | int resched = should_resched(); |
6df3cecb JK |
3830 | int ret = 0; |
3831 | ||
f607c668 PZ |
3832 | lockdep_assert_held(lock); |
3833 | ||
95c354fe | 3834 | if (spin_needbreak(lock) || resched) { |
1da177e4 | 3835 | spin_unlock(lock); |
d86ee480 | 3836 | if (resched) |
95c354fe NP |
3837 | __cond_resched(); |
3838 | else | |
3839 | cpu_relax(); | |
6df3cecb | 3840 | ret = 1; |
1da177e4 | 3841 | spin_lock(lock); |
1da177e4 | 3842 | } |
6df3cecb | 3843 | return ret; |
1da177e4 | 3844 | } |
613afbf8 | 3845 | EXPORT_SYMBOL(__cond_resched_lock); |
1da177e4 | 3846 | |
613afbf8 | 3847 | int __sched __cond_resched_softirq(void) |
1da177e4 LT |
3848 | { |
3849 | BUG_ON(!in_softirq()); | |
3850 | ||
d86ee480 | 3851 | if (should_resched()) { |
98d82567 | 3852 | local_bh_enable(); |
1da177e4 LT |
3853 | __cond_resched(); |
3854 | local_bh_disable(); | |
3855 | return 1; | |
3856 | } | |
3857 | return 0; | |
3858 | } | |
613afbf8 | 3859 | EXPORT_SYMBOL(__cond_resched_softirq); |
1da177e4 | 3860 | |
1da177e4 LT |
3861 | /** |
3862 | * yield - yield the current processor to other threads. | |
3863 | * | |
8e3fabfd PZ |
3864 | * Do not ever use this function, there's a 99% chance you're doing it wrong. |
3865 | * | |
3866 | * The scheduler is at all times free to pick the calling task as the most | |
3867 | * eligible task to run, if removing the yield() call from your code breaks | |
3868 | * it, its already broken. | |
3869 | * | |
3870 | * Typical broken usage is: | |
3871 | * | |
3872 | * while (!event) | |
3873 | * yield(); | |
3874 | * | |
3875 | * where one assumes that yield() will let 'the other' process run that will | |
3876 | * make event true. If the current task is a SCHED_FIFO task that will never | |
3877 | * happen. Never use yield() as a progress guarantee!! | |
3878 | * | |
3879 | * If you want to use yield() to wait for something, use wait_event(). | |
3880 | * If you want to use yield() to be 'nice' for others, use cond_resched(). | |
3881 | * If you still want to use yield(), do not! | |
1da177e4 LT |
3882 | */ |
3883 | void __sched yield(void) | |
3884 | { | |
3885 | set_current_state(TASK_RUNNING); | |
3886 | sys_sched_yield(); | |
3887 | } | |
1da177e4 LT |
3888 | EXPORT_SYMBOL(yield); |
3889 | ||
d95f4122 MG |
3890 | /** |
3891 | * yield_to - yield the current processor to another thread in | |
3892 | * your thread group, or accelerate that thread toward the | |
3893 | * processor it's on. | |
16addf95 RD |
3894 | * @p: target task |
3895 | * @preempt: whether task preemption is allowed or not | |
d95f4122 MG |
3896 | * |
3897 | * It's the caller's job to ensure that the target task struct | |
3898 | * can't go away on us before we can do any checks. | |
3899 | * | |
e69f6186 | 3900 | * Return: |
7b270f60 PZ |
3901 | * true (>0) if we indeed boosted the target task. |
3902 | * false (0) if we failed to boost the target. | |
3903 | * -ESRCH if there's no task to yield to. | |
d95f4122 MG |
3904 | */ |
3905 | bool __sched yield_to(struct task_struct *p, bool preempt) | |
3906 | { | |
3907 | struct task_struct *curr = current; | |
3908 | struct rq *rq, *p_rq; | |
3909 | unsigned long flags; | |
c3c18640 | 3910 | int yielded = 0; |
d95f4122 MG |
3911 | |
3912 | local_irq_save(flags); | |
3913 | rq = this_rq(); | |
3914 | ||
3915 | again: | |
3916 | p_rq = task_rq(p); | |
7b270f60 PZ |
3917 | /* |
3918 | * If we're the only runnable task on the rq and target rq also | |
3919 | * has only one task, there's absolutely no point in yielding. | |
3920 | */ | |
3921 | if (rq->nr_running == 1 && p_rq->nr_running == 1) { | |
3922 | yielded = -ESRCH; | |
3923 | goto out_irq; | |
3924 | } | |
3925 | ||
d95f4122 MG |
3926 | double_rq_lock(rq, p_rq); |
3927 | while (task_rq(p) != p_rq) { | |
3928 | double_rq_unlock(rq, p_rq); | |
3929 | goto again; | |
3930 | } | |
3931 | ||
3932 | if (!curr->sched_class->yield_to_task) | |
7b270f60 | 3933 | goto out_unlock; |
d95f4122 MG |
3934 | |
3935 | if (curr->sched_class != p->sched_class) | |
7b270f60 | 3936 | goto out_unlock; |
d95f4122 MG |
3937 | |
3938 | if (task_running(p_rq, p) || p->state) | |
7b270f60 | 3939 | goto out_unlock; |
d95f4122 MG |
3940 | |
3941 | yielded = curr->sched_class->yield_to_task(rq, p, preempt); | |
6d1cafd8 | 3942 | if (yielded) { |
d95f4122 | 3943 | schedstat_inc(rq, yld_count); |
6d1cafd8 VP |
3944 | /* |
3945 | * Make p's CPU reschedule; pick_next_entity takes care of | |
3946 | * fairness. | |
3947 | */ | |
3948 | if (preempt && rq != p_rq) | |
3949 | resched_task(p_rq->curr); | |
3950 | } | |
d95f4122 | 3951 | |
7b270f60 | 3952 | out_unlock: |
d95f4122 | 3953 | double_rq_unlock(rq, p_rq); |
7b270f60 | 3954 | out_irq: |
d95f4122 MG |
3955 | local_irq_restore(flags); |
3956 | ||
7b270f60 | 3957 | if (yielded > 0) |
d95f4122 MG |
3958 | schedule(); |
3959 | ||
3960 | return yielded; | |
3961 | } | |
3962 | EXPORT_SYMBOL_GPL(yield_to); | |
3963 | ||
1da177e4 | 3964 | /* |
41a2d6cf | 3965 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 | 3966 | * that process accounting knows that this is a task in IO wait state. |
1da177e4 LT |
3967 | */ |
3968 | void __sched io_schedule(void) | |
3969 | { | |
54d35f29 | 3970 | struct rq *rq = raw_rq(); |
1da177e4 | 3971 | |
0ff92245 | 3972 | delayacct_blkio_start(); |
1da177e4 | 3973 | atomic_inc(&rq->nr_iowait); |
73c10101 | 3974 | blk_flush_plug(current); |
8f0dfc34 | 3975 | current->in_iowait = 1; |
1da177e4 | 3976 | schedule(); |
8f0dfc34 | 3977 | current->in_iowait = 0; |
1da177e4 | 3978 | atomic_dec(&rq->nr_iowait); |
0ff92245 | 3979 | delayacct_blkio_end(); |
1da177e4 | 3980 | } |
1da177e4 LT |
3981 | EXPORT_SYMBOL(io_schedule); |
3982 | ||
3983 | long __sched io_schedule_timeout(long timeout) | |
3984 | { | |
54d35f29 | 3985 | struct rq *rq = raw_rq(); |
1da177e4 LT |
3986 | long ret; |
3987 | ||
0ff92245 | 3988 | delayacct_blkio_start(); |
1da177e4 | 3989 | atomic_inc(&rq->nr_iowait); |
73c10101 | 3990 | blk_flush_plug(current); |
8f0dfc34 | 3991 | current->in_iowait = 1; |
1da177e4 | 3992 | ret = schedule_timeout(timeout); |
8f0dfc34 | 3993 | current->in_iowait = 0; |
1da177e4 | 3994 | atomic_dec(&rq->nr_iowait); |
0ff92245 | 3995 | delayacct_blkio_end(); |
1da177e4 LT |
3996 | return ret; |
3997 | } | |
3998 | ||
3999 | /** | |
4000 | * sys_sched_get_priority_max - return maximum RT priority. | |
4001 | * @policy: scheduling class. | |
4002 | * | |
e69f6186 YB |
4003 | * Return: On success, this syscall returns the maximum |
4004 | * rt_priority that can be used by a given scheduling class. | |
4005 | * On failure, a negative error code is returned. | |
1da177e4 | 4006 | */ |
5add95d4 | 4007 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
1da177e4 LT |
4008 | { |
4009 | int ret = -EINVAL; | |
4010 | ||
4011 | switch (policy) { | |
4012 | case SCHED_FIFO: | |
4013 | case SCHED_RR: | |
4014 | ret = MAX_USER_RT_PRIO-1; | |
4015 | break; | |
4016 | case SCHED_NORMAL: | |
b0a9499c | 4017 | case SCHED_BATCH: |
dd41f596 | 4018 | case SCHED_IDLE: |
1da177e4 LT |
4019 | ret = 0; |
4020 | break; | |
4021 | } | |
4022 | return ret; | |
4023 | } | |
4024 | ||
4025 | /** | |
4026 | * sys_sched_get_priority_min - return minimum RT priority. | |
4027 | * @policy: scheduling class. | |
4028 | * | |
e69f6186 YB |
4029 | * Return: On success, this syscall returns the minimum |
4030 | * rt_priority that can be used by a given scheduling class. | |
4031 | * On failure, a negative error code is returned. | |
1da177e4 | 4032 | */ |
5add95d4 | 4033 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
1da177e4 LT |
4034 | { |
4035 | int ret = -EINVAL; | |
4036 | ||
4037 | switch (policy) { | |
4038 | case SCHED_FIFO: | |
4039 | case SCHED_RR: | |
4040 | ret = 1; | |
4041 | break; | |
4042 | case SCHED_NORMAL: | |
b0a9499c | 4043 | case SCHED_BATCH: |
dd41f596 | 4044 | case SCHED_IDLE: |
1da177e4 LT |
4045 | ret = 0; |
4046 | } | |
4047 | return ret; | |
4048 | } | |
4049 | ||
4050 | /** | |
4051 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4052 | * @pid: pid of the process. | |
4053 | * @interval: userspace pointer to the timeslice value. | |
4054 | * | |
4055 | * this syscall writes the default timeslice value of a given process | |
4056 | * into the user-space timespec buffer. A value of '0' means infinity. | |
e69f6186 YB |
4057 | * |
4058 | * Return: On success, 0 and the timeslice is in @interval. Otherwise, | |
4059 | * an error code. | |
1da177e4 | 4060 | */ |
17da2bd9 | 4061 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
754fe8d2 | 4062 | struct timespec __user *, interval) |
1da177e4 | 4063 | { |
36c8b586 | 4064 | struct task_struct *p; |
a4ec24b4 | 4065 | unsigned int time_slice; |
dba091b9 TG |
4066 | unsigned long flags; |
4067 | struct rq *rq; | |
3a5c359a | 4068 | int retval; |
1da177e4 | 4069 | struct timespec t; |
1da177e4 LT |
4070 | |
4071 | if (pid < 0) | |
3a5c359a | 4072 | return -EINVAL; |
1da177e4 LT |
4073 | |
4074 | retval = -ESRCH; | |
1a551ae7 | 4075 | rcu_read_lock(); |
1da177e4 LT |
4076 | p = find_process_by_pid(pid); |
4077 | if (!p) | |
4078 | goto out_unlock; | |
4079 | ||
4080 | retval = security_task_getscheduler(p); | |
4081 | if (retval) | |
4082 | goto out_unlock; | |
4083 | ||
dba091b9 TG |
4084 | rq = task_rq_lock(p, &flags); |
4085 | time_slice = p->sched_class->get_rr_interval(rq, p); | |
0122ec5b | 4086 | task_rq_unlock(rq, p, &flags); |
a4ec24b4 | 4087 | |
1a551ae7 | 4088 | rcu_read_unlock(); |
a4ec24b4 | 4089 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4090 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4091 | return retval; |
3a5c359a | 4092 | |
1da177e4 | 4093 | out_unlock: |
1a551ae7 | 4094 | rcu_read_unlock(); |
1da177e4 LT |
4095 | return retval; |
4096 | } | |
4097 | ||
7c731e0a | 4098 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
36c8b586 | 4099 | |
82a1fcb9 | 4100 | void sched_show_task(struct task_struct *p) |
1da177e4 | 4101 | { |
1da177e4 | 4102 | unsigned long free = 0; |
4e79752c | 4103 | int ppid; |
36c8b586 | 4104 | unsigned state; |
1da177e4 | 4105 | |
1da177e4 | 4106 | state = p->state ? __ffs(p->state) + 1 : 0; |
28d0686c | 4107 | printk(KERN_INFO "%-15.15s %c", p->comm, |
2ed6e34f | 4108 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 4109 | #if BITS_PER_LONG == 32 |
1da177e4 | 4110 | if (state == TASK_RUNNING) |
3df0fc5b | 4111 | printk(KERN_CONT " running "); |
1da177e4 | 4112 | else |
3df0fc5b | 4113 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
4114 | #else |
4115 | if (state == TASK_RUNNING) | |
3df0fc5b | 4116 | printk(KERN_CONT " running task "); |
1da177e4 | 4117 | else |
3df0fc5b | 4118 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
4119 | #endif |
4120 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
7c9f8861 | 4121 | free = stack_not_used(p); |
1da177e4 | 4122 | #endif |
4e79752c PM |
4123 | rcu_read_lock(); |
4124 | ppid = task_pid_nr(rcu_dereference(p->real_parent)); | |
4125 | rcu_read_unlock(); | |
3df0fc5b | 4126 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
4e79752c | 4127 | task_pid_nr(p), ppid, |
aa47b7e0 | 4128 | (unsigned long)task_thread_info(p)->flags); |
1da177e4 | 4129 | |
3d1cb205 | 4130 | print_worker_info(KERN_INFO, p); |
5fb5e6de | 4131 | show_stack(p, NULL); |
1da177e4 LT |
4132 | } |
4133 | ||
e59e2ae2 | 4134 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 4135 | { |
36c8b586 | 4136 | struct task_struct *g, *p; |
1da177e4 | 4137 | |
4bd77321 | 4138 | #if BITS_PER_LONG == 32 |
3df0fc5b PZ |
4139 | printk(KERN_INFO |
4140 | " task PC stack pid father\n"); | |
1da177e4 | 4141 | #else |
3df0fc5b PZ |
4142 | printk(KERN_INFO |
4143 | " task PC stack pid father\n"); | |
1da177e4 | 4144 | #endif |
510f5acc | 4145 | rcu_read_lock(); |
1da177e4 LT |
4146 | do_each_thread(g, p) { |
4147 | /* | |
4148 | * reset the NMI-timeout, listing all files on a slow | |
25985edc | 4149 | * console might take a lot of time: |
1da177e4 LT |
4150 | */ |
4151 | touch_nmi_watchdog(); | |
39bc89fd | 4152 | if (!state_filter || (p->state & state_filter)) |
82a1fcb9 | 4153 | sched_show_task(p); |
1da177e4 LT |
4154 | } while_each_thread(g, p); |
4155 | ||
04c9167f JF |
4156 | touch_all_softlockup_watchdogs(); |
4157 | ||
dd41f596 IM |
4158 | #ifdef CONFIG_SCHED_DEBUG |
4159 | sysrq_sched_debug_show(); | |
4160 | #endif | |
510f5acc | 4161 | rcu_read_unlock(); |
e59e2ae2 IM |
4162 | /* |
4163 | * Only show locks if all tasks are dumped: | |
4164 | */ | |
93335a21 | 4165 | if (!state_filter) |
e59e2ae2 | 4166 | debug_show_all_locks(); |
1da177e4 LT |
4167 | } |
4168 | ||
0db0628d | 4169 | void init_idle_bootup_task(struct task_struct *idle) |
1df21055 | 4170 | { |
dd41f596 | 4171 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
4172 | } |
4173 | ||
f340c0d1 IM |
4174 | /** |
4175 | * init_idle - set up an idle thread for a given CPU | |
4176 | * @idle: task in question | |
4177 | * @cpu: cpu the idle task belongs to | |
4178 | * | |
4179 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
4180 | * flag, to make booting more robust. | |
4181 | */ | |
0db0628d | 4182 | void init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 4183 | { |
70b97a7f | 4184 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
4185 | unsigned long flags; |
4186 | ||
05fa785c | 4187 | raw_spin_lock_irqsave(&rq->lock, flags); |
5cbd54ef | 4188 | |
dd41f596 | 4189 | __sched_fork(idle); |
06b83b5f | 4190 | idle->state = TASK_RUNNING; |
dd41f596 IM |
4191 | idle->se.exec_start = sched_clock(); |
4192 | ||
1e1b6c51 | 4193 | do_set_cpus_allowed(idle, cpumask_of(cpu)); |
6506cf6c PZ |
4194 | /* |
4195 | * We're having a chicken and egg problem, even though we are | |
4196 | * holding rq->lock, the cpu isn't yet set to this cpu so the | |
4197 | * lockdep check in task_group() will fail. | |
4198 | * | |
4199 | * Similar case to sched_fork(). / Alternatively we could | |
4200 | * use task_rq_lock() here and obtain the other rq->lock. | |
4201 | * | |
4202 | * Silence PROVE_RCU | |
4203 | */ | |
4204 | rcu_read_lock(); | |
dd41f596 | 4205 | __set_task_cpu(idle, cpu); |
6506cf6c | 4206 | rcu_read_unlock(); |
1da177e4 | 4207 | |
1da177e4 | 4208 | rq->curr = rq->idle = idle; |
3ca7a440 PZ |
4209 | #if defined(CONFIG_SMP) |
4210 | idle->on_cpu = 1; | |
4866cde0 | 4211 | #endif |
05fa785c | 4212 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1da177e4 LT |
4213 | |
4214 | /* Set the preempt count _outside_ the spinlocks! */ | |
a1261f54 | 4215 | task_thread_info(idle)->preempt_count = 0; |
55cd5340 | 4216 | |
dd41f596 IM |
4217 | /* |
4218 | * The idle tasks have their own, simple scheduling class: | |
4219 | */ | |
4220 | idle->sched_class = &idle_sched_class; | |
868baf07 | 4221 | ftrace_graph_init_idle_task(idle, cpu); |
45eacc69 | 4222 | vtime_init_idle(idle, cpu); |
f1c6f1a7 CE |
4223 | #if defined(CONFIG_SMP) |
4224 | sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); | |
4225 | #endif | |
19978ca6 IM |
4226 | } |
4227 | ||
1da177e4 | 4228 | #ifdef CONFIG_SMP |
1e1b6c51 KM |
4229 | void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) |
4230 | { | |
4231 | if (p->sched_class && p->sched_class->set_cpus_allowed) | |
4232 | p->sched_class->set_cpus_allowed(p, new_mask); | |
4939602a PZ |
4233 | |
4234 | cpumask_copy(&p->cpus_allowed, new_mask); | |
29baa747 | 4235 | p->nr_cpus_allowed = cpumask_weight(new_mask); |
1e1b6c51 KM |
4236 | } |
4237 | ||
1da177e4 LT |
4238 | /* |
4239 | * This is how migration works: | |
4240 | * | |
969c7921 TH |
4241 | * 1) we invoke migration_cpu_stop() on the target CPU using |
4242 | * stop_one_cpu(). | |
4243 | * 2) stopper starts to run (implicitly forcing the migrated thread | |
4244 | * off the CPU) | |
4245 | * 3) it checks whether the migrated task is still in the wrong runqueue. | |
4246 | * 4) if it's in the wrong runqueue then the migration thread removes | |
1da177e4 | 4247 | * it and puts it into the right queue. |
969c7921 TH |
4248 | * 5) stopper completes and stop_one_cpu() returns and the migration |
4249 | * is done. | |
1da177e4 LT |
4250 | */ |
4251 | ||
4252 | /* | |
4253 | * Change a given task's CPU affinity. Migrate the thread to a | |
4254 | * proper CPU and schedule it away if the CPU it's executing on | |
4255 | * is removed from the allowed bitmask. | |
4256 | * | |
4257 | * NOTE: the caller must have a valid reference to the task, the | |
41a2d6cf | 4258 | * task must not exit() & deallocate itself prematurely. The |
1da177e4 LT |
4259 | * call is not atomic; no spinlocks may be held. |
4260 | */ | |
96f874e2 | 4261 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) |
1da177e4 LT |
4262 | { |
4263 | unsigned long flags; | |
70b97a7f | 4264 | struct rq *rq; |
969c7921 | 4265 | unsigned int dest_cpu; |
48f24c4d | 4266 | int ret = 0; |
1da177e4 LT |
4267 | |
4268 | rq = task_rq_lock(p, &flags); | |
e2912009 | 4269 | |
db44fc01 YZ |
4270 | if (cpumask_equal(&p->cpus_allowed, new_mask)) |
4271 | goto out; | |
4272 | ||
6ad4c188 | 4273 | if (!cpumask_intersects(new_mask, cpu_active_mask)) { |
1da177e4 LT |
4274 | ret = -EINVAL; |
4275 | goto out; | |
4276 | } | |
4277 | ||
1e1b6c51 | 4278 | do_set_cpus_allowed(p, new_mask); |
73fe6aae | 4279 | |
1da177e4 | 4280 | /* Can the task run on the task's current CPU? If so, we're done */ |
96f874e2 | 4281 | if (cpumask_test_cpu(task_cpu(p), new_mask)) |
1da177e4 LT |
4282 | goto out; |
4283 | ||
969c7921 | 4284 | dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); |
bd8e7dde | 4285 | if (p->on_rq) { |
969c7921 | 4286 | struct migration_arg arg = { p, dest_cpu }; |
1da177e4 | 4287 | /* Need help from migration thread: drop lock and wait. */ |
0122ec5b | 4288 | task_rq_unlock(rq, p, &flags); |
969c7921 | 4289 | stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); |
1da177e4 LT |
4290 | tlb_migrate_finish(p->mm); |
4291 | return 0; | |
4292 | } | |
4293 | out: | |
0122ec5b | 4294 | task_rq_unlock(rq, p, &flags); |
48f24c4d | 4295 | |
1da177e4 LT |
4296 | return ret; |
4297 | } | |
cd8ba7cd | 4298 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
1da177e4 LT |
4299 | |
4300 | /* | |
41a2d6cf | 4301 | * Move (not current) task off this cpu, onto dest cpu. We're doing |
1da177e4 LT |
4302 | * this because either it can't run here any more (set_cpus_allowed() |
4303 | * away from this CPU, or CPU going down), or because we're | |
4304 | * attempting to rebalance this task on exec (sched_exec). | |
4305 | * | |
4306 | * So we race with normal scheduler movements, but that's OK, as long | |
4307 | * as the task is no longer on this CPU. | |
efc30814 KK |
4308 | * |
4309 | * Returns non-zero if task was successfully migrated. | |
1da177e4 | 4310 | */ |
efc30814 | 4311 | static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
1da177e4 | 4312 | { |
70b97a7f | 4313 | struct rq *rq_dest, *rq_src; |
e2912009 | 4314 | int ret = 0; |
1da177e4 | 4315 | |
e761b772 | 4316 | if (unlikely(!cpu_active(dest_cpu))) |
efc30814 | 4317 | return ret; |
1da177e4 LT |
4318 | |
4319 | rq_src = cpu_rq(src_cpu); | |
4320 | rq_dest = cpu_rq(dest_cpu); | |
4321 | ||
0122ec5b | 4322 | raw_spin_lock(&p->pi_lock); |
1da177e4 LT |
4323 | double_rq_lock(rq_src, rq_dest); |
4324 | /* Already moved. */ | |
4325 | if (task_cpu(p) != src_cpu) | |
b1e38734 | 4326 | goto done; |
1da177e4 | 4327 | /* Affinity changed (again). */ |
fa17b507 | 4328 | if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) |
b1e38734 | 4329 | goto fail; |
1da177e4 | 4330 | |
e2912009 PZ |
4331 | /* |
4332 | * If we're not on a rq, the next wake-up will ensure we're | |
4333 | * placed properly. | |
4334 | */ | |
fd2f4419 | 4335 | if (p->on_rq) { |
4ca9b72b | 4336 | dequeue_task(rq_src, p, 0); |
e2912009 | 4337 | set_task_cpu(p, dest_cpu); |
4ca9b72b | 4338 | enqueue_task(rq_dest, p, 0); |
15afe09b | 4339 | check_preempt_curr(rq_dest, p, 0); |
1da177e4 | 4340 | } |
b1e38734 | 4341 | done: |
efc30814 | 4342 | ret = 1; |
b1e38734 | 4343 | fail: |
1da177e4 | 4344 | double_rq_unlock(rq_src, rq_dest); |
0122ec5b | 4345 | raw_spin_unlock(&p->pi_lock); |
efc30814 | 4346 | return ret; |
1da177e4 LT |
4347 | } |
4348 | ||
4349 | /* | |
969c7921 TH |
4350 | * migration_cpu_stop - this will be executed by a highprio stopper thread |
4351 | * and performs thread migration by bumping thread off CPU then | |
4352 | * 'pushing' onto another runqueue. | |
1da177e4 | 4353 | */ |
969c7921 | 4354 | static int migration_cpu_stop(void *data) |
1da177e4 | 4355 | { |
969c7921 | 4356 | struct migration_arg *arg = data; |
f7b4cddc | 4357 | |
969c7921 TH |
4358 | /* |
4359 | * The original target cpu might have gone down and we might | |
4360 | * be on another cpu but it doesn't matter. | |
4361 | */ | |
f7b4cddc | 4362 | local_irq_disable(); |
969c7921 | 4363 | __migrate_task(arg->task, raw_smp_processor_id(), arg->dest_cpu); |
f7b4cddc | 4364 | local_irq_enable(); |
1da177e4 | 4365 | return 0; |
f7b4cddc ON |
4366 | } |
4367 | ||
1da177e4 | 4368 | #ifdef CONFIG_HOTPLUG_CPU |
48c5ccae | 4369 | |
054b9108 | 4370 | /* |
48c5ccae PZ |
4371 | * Ensures that the idle task is using init_mm right before its cpu goes |
4372 | * offline. | |
054b9108 | 4373 | */ |
48c5ccae | 4374 | void idle_task_exit(void) |
1da177e4 | 4375 | { |
48c5ccae | 4376 | struct mm_struct *mm = current->active_mm; |
e76bd8d9 | 4377 | |
48c5ccae | 4378 | BUG_ON(cpu_online(smp_processor_id())); |
e76bd8d9 | 4379 | |
48c5ccae PZ |
4380 | if (mm != &init_mm) |
4381 | switch_mm(mm, &init_mm, current); | |
4382 | mmdrop(mm); | |
1da177e4 LT |
4383 | } |
4384 | ||
4385 | /* | |
5d180232 PZ |
4386 | * Since this CPU is going 'away' for a while, fold any nr_active delta |
4387 | * we might have. Assumes we're called after migrate_tasks() so that the | |
4388 | * nr_active count is stable. | |
4389 | * | |
4390 | * Also see the comment "Global load-average calculations". | |
1da177e4 | 4391 | */ |
5d180232 | 4392 | static void calc_load_migrate(struct rq *rq) |
1da177e4 | 4393 | { |
5d180232 PZ |
4394 | long delta = calc_load_fold_active(rq); |
4395 | if (delta) | |
4396 | atomic_long_add(delta, &calc_load_tasks); | |
1da177e4 LT |
4397 | } |
4398 | ||
48f24c4d | 4399 | /* |
48c5ccae PZ |
4400 | * Migrate all tasks from the rq, sleeping tasks will be migrated by |
4401 | * try_to_wake_up()->select_task_rq(). | |
4402 | * | |
4403 | * Called with rq->lock held even though we'er in stop_machine() and | |
4404 | * there's no concurrency possible, we hold the required locks anyway | |
4405 | * because of lock validation efforts. | |
1da177e4 | 4406 | */ |
48c5ccae | 4407 | static void migrate_tasks(unsigned int dead_cpu) |
1da177e4 | 4408 | { |
70b97a7f | 4409 | struct rq *rq = cpu_rq(dead_cpu); |
48c5ccae PZ |
4410 | struct task_struct *next, *stop = rq->stop; |
4411 | int dest_cpu; | |
1da177e4 LT |
4412 | |
4413 | /* | |
48c5ccae PZ |
4414 | * Fudge the rq selection such that the below task selection loop |
4415 | * doesn't get stuck on the currently eligible stop task. | |
4416 | * | |
4417 | * We're currently inside stop_machine() and the rq is either stuck | |
4418 | * in the stop_machine_cpu_stop() loop, or we're executing this code, | |
4419 | * either way we should never end up calling schedule() until we're | |
4420 | * done here. | |
1da177e4 | 4421 | */ |
48c5ccae | 4422 | rq->stop = NULL; |
48f24c4d | 4423 | |
77bd3970 FW |
4424 | /* |
4425 | * put_prev_task() and pick_next_task() sched | |
4426 | * class method both need to have an up-to-date | |
4427 | * value of rq->clock[_task] | |
4428 | */ | |
4429 | update_rq_clock(rq); | |
4430 | ||
dd41f596 | 4431 | for ( ; ; ) { |
48c5ccae PZ |
4432 | /* |
4433 | * There's this thread running, bail when that's the only | |
4434 | * remaining thread. | |
4435 | */ | |
4436 | if (rq->nr_running == 1) | |
dd41f596 | 4437 | break; |
48c5ccae | 4438 | |
b67802ea | 4439 | next = pick_next_task(rq); |
48c5ccae | 4440 | BUG_ON(!next); |
79c53799 | 4441 | next->sched_class->put_prev_task(rq, next); |
e692ab53 | 4442 | |
48c5ccae PZ |
4443 | /* Find suitable destination for @next, with force if needed. */ |
4444 | dest_cpu = select_fallback_rq(dead_cpu, next); | |
4445 | raw_spin_unlock(&rq->lock); | |
4446 | ||
4447 | __migrate_task(next, dead_cpu, dest_cpu); | |
4448 | ||
4449 | raw_spin_lock(&rq->lock); | |
1da177e4 | 4450 | } |
dce48a84 | 4451 | |
48c5ccae | 4452 | rq->stop = stop; |
dce48a84 | 4453 | } |
48c5ccae | 4454 | |
1da177e4 LT |
4455 | #endif /* CONFIG_HOTPLUG_CPU */ |
4456 | ||
e692ab53 NP |
4457 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
4458 | ||
4459 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
4460 | { |
4461 | .procname = "sched_domain", | |
c57baf1e | 4462 | .mode = 0555, |
e0361851 | 4463 | }, |
56992309 | 4464 | {} |
e692ab53 NP |
4465 | }; |
4466 | ||
4467 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 AD |
4468 | { |
4469 | .procname = "kernel", | |
c57baf1e | 4470 | .mode = 0555, |
e0361851 AD |
4471 | .child = sd_ctl_dir, |
4472 | }, | |
56992309 | 4473 | {} |
e692ab53 NP |
4474 | }; |
4475 | ||
4476 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
4477 | { | |
4478 | struct ctl_table *entry = | |
5cf9f062 | 4479 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
e692ab53 | 4480 | |
e692ab53 NP |
4481 | return entry; |
4482 | } | |
4483 | ||
6382bc90 MM |
4484 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
4485 | { | |
cd790076 | 4486 | struct ctl_table *entry; |
6382bc90 | 4487 | |
cd790076 MM |
4488 | /* |
4489 | * In the intermediate directories, both the child directory and | |
4490 | * procname are dynamically allocated and could fail but the mode | |
41a2d6cf | 4491 | * will always be set. In the lowest directory the names are |
cd790076 MM |
4492 | * static strings and all have proc handlers. |
4493 | */ | |
4494 | for (entry = *tablep; entry->mode; entry++) { | |
6382bc90 MM |
4495 | if (entry->child) |
4496 | sd_free_ctl_entry(&entry->child); | |
cd790076 MM |
4497 | if (entry->proc_handler == NULL) |
4498 | kfree(entry->procname); | |
4499 | } | |
6382bc90 MM |
4500 | |
4501 | kfree(*tablep); | |
4502 | *tablep = NULL; | |
4503 | } | |
4504 | ||
201c373e | 4505 | static int min_load_idx = 0; |
fd9b86d3 | 4506 | static int max_load_idx = CPU_LOAD_IDX_MAX-1; |
201c373e | 4507 | |
e692ab53 | 4508 | static void |
e0361851 | 4509 | set_table_entry(struct ctl_table *entry, |
e692ab53 | 4510 | const char *procname, void *data, int maxlen, |
201c373e NK |
4511 | umode_t mode, proc_handler *proc_handler, |
4512 | bool load_idx) | |
e692ab53 | 4513 | { |
e692ab53 NP |
4514 | entry->procname = procname; |
4515 | entry->data = data; | |
4516 | entry->maxlen = maxlen; | |
4517 | entry->mode = mode; | |
4518 | entry->proc_handler = proc_handler; | |
201c373e NK |
4519 | |
4520 | if (load_idx) { | |
4521 | entry->extra1 = &min_load_idx; | |
4522 | entry->extra2 = &max_load_idx; | |
4523 | } | |
e692ab53 NP |
4524 | } |
4525 | ||
4526 | static struct ctl_table * | |
4527 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
4528 | { | |
a5d8c348 | 4529 | struct ctl_table *table = sd_alloc_ctl_entry(13); |
e692ab53 | 4530 | |
ad1cdc1d MM |
4531 | if (table == NULL) |
4532 | return NULL; | |
4533 | ||
e0361851 | 4534 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
201c373e | 4535 | sizeof(long), 0644, proc_doulongvec_minmax, false); |
e0361851 | 4536 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
201c373e | 4537 | sizeof(long), 0644, proc_doulongvec_minmax, false); |
e0361851 | 4538 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
201c373e | 4539 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 4540 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
201c373e | 4541 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 4542 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
201c373e | 4543 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 4544 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
201c373e | 4545 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 4546 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
201c373e | 4547 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 4548 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
201c373e | 4549 | sizeof(int), 0644, proc_dointvec_minmax, false); |
e0361851 | 4550 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
201c373e | 4551 | sizeof(int), 0644, proc_dointvec_minmax, false); |
ace8b3d6 | 4552 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 | 4553 | &sd->cache_nice_tries, |
201c373e | 4554 | sizeof(int), 0644, proc_dointvec_minmax, false); |
ace8b3d6 | 4555 | set_table_entry(&table[10], "flags", &sd->flags, |
201c373e | 4556 | sizeof(int), 0644, proc_dointvec_minmax, false); |
a5d8c348 | 4557 | set_table_entry(&table[11], "name", sd->name, |
201c373e | 4558 | CORENAME_MAX_SIZE, 0444, proc_dostring, false); |
a5d8c348 | 4559 | /* &table[12] is terminator */ |
e692ab53 NP |
4560 | |
4561 | return table; | |
4562 | } | |
4563 | ||
be7002e6 | 4564 | static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
e692ab53 NP |
4565 | { |
4566 | struct ctl_table *entry, *table; | |
4567 | struct sched_domain *sd; | |
4568 | int domain_num = 0, i; | |
4569 | char buf[32]; | |
4570 | ||
4571 | for_each_domain(cpu, sd) | |
4572 | domain_num++; | |
4573 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
ad1cdc1d MM |
4574 | if (table == NULL) |
4575 | return NULL; | |
e692ab53 NP |
4576 | |
4577 | i = 0; | |
4578 | for_each_domain(cpu, sd) { | |
4579 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 4580 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 4581 | entry->mode = 0555; |
e692ab53 NP |
4582 | entry->child = sd_alloc_ctl_domain_table(sd); |
4583 | entry++; | |
4584 | i++; | |
4585 | } | |
4586 | return table; | |
4587 | } | |
4588 | ||
4589 | static struct ctl_table_header *sd_sysctl_header; | |
6382bc90 | 4590 | static void register_sched_domain_sysctl(void) |
e692ab53 | 4591 | { |
6ad4c188 | 4592 | int i, cpu_num = num_possible_cpus(); |
e692ab53 NP |
4593 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
4594 | char buf[32]; | |
4595 | ||
7378547f MM |
4596 | WARN_ON(sd_ctl_dir[0].child); |
4597 | sd_ctl_dir[0].child = entry; | |
4598 | ||
ad1cdc1d MM |
4599 | if (entry == NULL) |
4600 | return; | |
4601 | ||
6ad4c188 | 4602 | for_each_possible_cpu(i) { |
e692ab53 | 4603 | snprintf(buf, 32, "cpu%d", i); |
e692ab53 | 4604 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 4605 | entry->mode = 0555; |
e692ab53 | 4606 | entry->child = sd_alloc_ctl_cpu_table(i); |
97b6ea7b | 4607 | entry++; |
e692ab53 | 4608 | } |
7378547f MM |
4609 | |
4610 | WARN_ON(sd_sysctl_header); | |
e692ab53 NP |
4611 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
4612 | } | |
6382bc90 | 4613 | |
7378547f | 4614 | /* may be called multiple times per register */ |
6382bc90 MM |
4615 | static void unregister_sched_domain_sysctl(void) |
4616 | { | |
7378547f MM |
4617 | if (sd_sysctl_header) |
4618 | unregister_sysctl_table(sd_sysctl_header); | |
6382bc90 | 4619 | sd_sysctl_header = NULL; |
7378547f MM |
4620 | if (sd_ctl_dir[0].child) |
4621 | sd_free_ctl_entry(&sd_ctl_dir[0].child); | |
6382bc90 | 4622 | } |
e692ab53 | 4623 | #else |
6382bc90 MM |
4624 | static void register_sched_domain_sysctl(void) |
4625 | { | |
4626 | } | |
4627 | static void unregister_sched_domain_sysctl(void) | |
e692ab53 NP |
4628 | { |
4629 | } | |
4630 | #endif | |
4631 | ||
1f11eb6a GH |
4632 | static void set_rq_online(struct rq *rq) |
4633 | { | |
4634 | if (!rq->online) { | |
4635 | const struct sched_class *class; | |
4636 | ||
c6c4927b | 4637 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
4638 | rq->online = 1; |
4639 | ||
4640 | for_each_class(class) { | |
4641 | if (class->rq_online) | |
4642 | class->rq_online(rq); | |
4643 | } | |
4644 | } | |
4645 | } | |
4646 | ||
4647 | static void set_rq_offline(struct rq *rq) | |
4648 | { | |
4649 | if (rq->online) { | |
4650 | const struct sched_class *class; | |
4651 | ||
4652 | for_each_class(class) { | |
4653 | if (class->rq_offline) | |
4654 | class->rq_offline(rq); | |
4655 | } | |
4656 | ||
c6c4927b | 4657 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
4658 | rq->online = 0; |
4659 | } | |
4660 | } | |
4661 | ||
1da177e4 LT |
4662 | /* |
4663 | * migration_call - callback that gets triggered when a CPU is added. | |
4664 | * Here we can start up the necessary migration thread for the new CPU. | |
4665 | */ | |
0db0628d | 4666 | static int |
48f24c4d | 4667 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
1da177e4 | 4668 | { |
48f24c4d | 4669 | int cpu = (long)hcpu; |
1da177e4 | 4670 | unsigned long flags; |
969c7921 | 4671 | struct rq *rq = cpu_rq(cpu); |
1da177e4 | 4672 | |
48c5ccae | 4673 | switch (action & ~CPU_TASKS_FROZEN) { |
5be9361c | 4674 | |
1da177e4 | 4675 | case CPU_UP_PREPARE: |
a468d389 | 4676 | rq->calc_load_update = calc_load_update; |
1da177e4 | 4677 | break; |
48f24c4d | 4678 | |
1da177e4 | 4679 | case CPU_ONLINE: |
1f94ef59 | 4680 | /* Update our root-domain */ |
05fa785c | 4681 | raw_spin_lock_irqsave(&rq->lock, flags); |
1f94ef59 | 4682 | if (rq->rd) { |
c6c4927b | 4683 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
1f11eb6a GH |
4684 | |
4685 | set_rq_online(rq); | |
1f94ef59 | 4686 | } |
05fa785c | 4687 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1da177e4 | 4688 | break; |
48f24c4d | 4689 | |
1da177e4 | 4690 | #ifdef CONFIG_HOTPLUG_CPU |
08f503b0 | 4691 | case CPU_DYING: |
317f3941 | 4692 | sched_ttwu_pending(); |
57d885fe | 4693 | /* Update our root-domain */ |
05fa785c | 4694 | raw_spin_lock_irqsave(&rq->lock, flags); |
57d885fe | 4695 | if (rq->rd) { |
c6c4927b | 4696 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
1f11eb6a | 4697 | set_rq_offline(rq); |
57d885fe | 4698 | } |
48c5ccae PZ |
4699 | migrate_tasks(cpu); |
4700 | BUG_ON(rq->nr_running != 1); /* the migration thread */ | |
05fa785c | 4701 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5d180232 | 4702 | break; |
48c5ccae | 4703 | |
5d180232 | 4704 | case CPU_DEAD: |
f319da0c | 4705 | calc_load_migrate(rq); |
57d885fe | 4706 | break; |
1da177e4 LT |
4707 | #endif |
4708 | } | |
49c022e6 PZ |
4709 | |
4710 | update_max_interval(); | |
4711 | ||
1da177e4 LT |
4712 | return NOTIFY_OK; |
4713 | } | |
4714 | ||
f38b0820 PM |
4715 | /* |
4716 | * Register at high priority so that task migration (migrate_all_tasks) | |
4717 | * happens before everything else. This has to be lower priority than | |
cdd6c482 | 4718 | * the notifier in the perf_event subsystem, though. |
1da177e4 | 4719 | */ |
0db0628d | 4720 | static struct notifier_block migration_notifier = { |
1da177e4 | 4721 | .notifier_call = migration_call, |
50a323b7 | 4722 | .priority = CPU_PRI_MIGRATION, |
1da177e4 LT |
4723 | }; |
4724 | ||
0db0628d | 4725 | static int sched_cpu_active(struct notifier_block *nfb, |
3a101d05 TH |
4726 | unsigned long action, void *hcpu) |
4727 | { | |
4728 | switch (action & ~CPU_TASKS_FROZEN) { | |
5fbd036b | 4729 | case CPU_STARTING: |
3a101d05 TH |
4730 | case CPU_DOWN_FAILED: |
4731 | set_cpu_active((long)hcpu, true); | |
4732 | return NOTIFY_OK; | |
4733 | default: | |
4734 | return NOTIFY_DONE; | |
4735 | } | |
4736 | } | |
4737 | ||
0db0628d | 4738 | static int sched_cpu_inactive(struct notifier_block *nfb, |
3a101d05 TH |
4739 | unsigned long action, void *hcpu) |
4740 | { | |
4741 | switch (action & ~CPU_TASKS_FROZEN) { | |
4742 | case CPU_DOWN_PREPARE: | |
4743 | set_cpu_active((long)hcpu, false); | |
4744 | return NOTIFY_OK; | |
4745 | default: | |
4746 | return NOTIFY_DONE; | |
4747 | } | |
4748 | } | |
4749 | ||
7babe8db | 4750 | static int __init migration_init(void) |
1da177e4 LT |
4751 | { |
4752 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 4753 | int err; |
48f24c4d | 4754 | |
3a101d05 | 4755 | /* Initialize migration for the boot CPU */ |
07dccf33 AM |
4756 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
4757 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
4758 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
4759 | register_cpu_notifier(&migration_notifier); | |
7babe8db | 4760 | |
3a101d05 TH |
4761 | /* Register cpu active notifiers */ |
4762 | cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); | |
4763 | cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); | |
4764 | ||
a004cd42 | 4765 | return 0; |
1da177e4 | 4766 | } |
7babe8db | 4767 | early_initcall(migration_init); |
1da177e4 LT |
4768 | #endif |
4769 | ||
4770 | #ifdef CONFIG_SMP | |
476f3534 | 4771 | |
4cb98839 PZ |
4772 | static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ |
4773 | ||
3e9830dc | 4774 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff | 4775 | |
d039ac60 | 4776 | static __read_mostly int sched_debug_enabled; |
f6630114 | 4777 | |
d039ac60 | 4778 | static int __init sched_debug_setup(char *str) |
f6630114 | 4779 | { |
d039ac60 | 4780 | sched_debug_enabled = 1; |
f6630114 MT |
4781 | |
4782 | return 0; | |
4783 | } | |
d039ac60 PZ |
4784 | early_param("sched_debug", sched_debug_setup); |
4785 | ||
4786 | static inline bool sched_debug(void) | |
4787 | { | |
4788 | return sched_debug_enabled; | |
4789 | } | |
f6630114 | 4790 | |
7c16ec58 | 4791 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
96f874e2 | 4792 | struct cpumask *groupmask) |
1da177e4 | 4793 | { |
4dcf6aff | 4794 | struct sched_group *group = sd->groups; |
434d53b0 | 4795 | char str[256]; |
1da177e4 | 4796 | |
968ea6d8 | 4797 | cpulist_scnprintf(str, sizeof(str), sched_domain_span(sd)); |
96f874e2 | 4798 | cpumask_clear(groupmask); |
4dcf6aff IM |
4799 | |
4800 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
4801 | ||
4802 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
3df0fc5b | 4803 | printk("does not load-balance\n"); |
4dcf6aff | 4804 | if (sd->parent) |
3df0fc5b PZ |
4805 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
4806 | " has parent"); | |
4dcf6aff | 4807 | return -1; |
41c7ce9a NP |
4808 | } |
4809 | ||
3df0fc5b | 4810 | printk(KERN_CONT "span %s level %s\n", str, sd->name); |
4dcf6aff | 4811 | |
758b2cdc | 4812 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
3df0fc5b PZ |
4813 | printk(KERN_ERR "ERROR: domain->span does not contain " |
4814 | "CPU%d\n", cpu); | |
4dcf6aff | 4815 | } |
758b2cdc | 4816 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
3df0fc5b PZ |
4817 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
4818 | " CPU%d\n", cpu); | |
4dcf6aff | 4819 | } |
1da177e4 | 4820 | |
4dcf6aff | 4821 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 4822 | do { |
4dcf6aff | 4823 | if (!group) { |
3df0fc5b PZ |
4824 | printk("\n"); |
4825 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
4826 | break; |
4827 | } | |
4828 | ||
c3decf0d PZ |
4829 | /* |
4830 | * Even though we initialize ->power to something semi-sane, | |
4831 | * we leave power_orig unset. This allows us to detect if | |
4832 | * domain iteration is still funny without causing /0 traps. | |
4833 | */ | |
4834 | if (!group->sgp->power_orig) { | |
3df0fc5b PZ |
4835 | printk(KERN_CONT "\n"); |
4836 | printk(KERN_ERR "ERROR: domain->cpu_power not " | |
4837 | "set\n"); | |
4dcf6aff IM |
4838 | break; |
4839 | } | |
1da177e4 | 4840 | |
758b2cdc | 4841 | if (!cpumask_weight(sched_group_cpus(group))) { |
3df0fc5b PZ |
4842 | printk(KERN_CONT "\n"); |
4843 | printk(KERN_ERR "ERROR: empty group\n"); | |
4dcf6aff IM |
4844 | break; |
4845 | } | |
1da177e4 | 4846 | |
cb83b629 PZ |
4847 | if (!(sd->flags & SD_OVERLAP) && |
4848 | cpumask_intersects(groupmask, sched_group_cpus(group))) { | |
3df0fc5b PZ |
4849 | printk(KERN_CONT "\n"); |
4850 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
4dcf6aff IM |
4851 | break; |
4852 | } | |
1da177e4 | 4853 | |
758b2cdc | 4854 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
1da177e4 | 4855 | |
968ea6d8 | 4856 | cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group)); |
381512cf | 4857 | |
3df0fc5b | 4858 | printk(KERN_CONT " %s", str); |
9c3f75cb | 4859 | if (group->sgp->power != SCHED_POWER_SCALE) { |
3df0fc5b | 4860 | printk(KERN_CONT " (cpu_power = %d)", |
9c3f75cb | 4861 | group->sgp->power); |
381512cf | 4862 | } |
1da177e4 | 4863 | |
4dcf6aff IM |
4864 | group = group->next; |
4865 | } while (group != sd->groups); | |
3df0fc5b | 4866 | printk(KERN_CONT "\n"); |
1da177e4 | 4867 | |
758b2cdc | 4868 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
3df0fc5b | 4869 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
1da177e4 | 4870 | |
758b2cdc RR |
4871 | if (sd->parent && |
4872 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) | |
3df0fc5b PZ |
4873 | printk(KERN_ERR "ERROR: parent span is not a superset " |
4874 | "of domain->span\n"); | |
4dcf6aff IM |
4875 | return 0; |
4876 | } | |
1da177e4 | 4877 | |
4dcf6aff IM |
4878 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
4879 | { | |
4880 | int level = 0; | |
1da177e4 | 4881 | |
d039ac60 | 4882 | if (!sched_debug_enabled) |
f6630114 MT |
4883 | return; |
4884 | ||
4dcf6aff IM |
4885 | if (!sd) { |
4886 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
4887 | return; | |
4888 | } | |
1da177e4 | 4889 | |
4dcf6aff IM |
4890 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
4891 | ||
4892 | for (;;) { | |
4cb98839 | 4893 | if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) |
4dcf6aff | 4894 | break; |
1da177e4 LT |
4895 | level++; |
4896 | sd = sd->parent; | |
33859f7f | 4897 | if (!sd) |
4dcf6aff IM |
4898 | break; |
4899 | } | |
1da177e4 | 4900 | } |
6d6bc0ad | 4901 | #else /* !CONFIG_SCHED_DEBUG */ |
48f24c4d | 4902 | # define sched_domain_debug(sd, cpu) do { } while (0) |
d039ac60 PZ |
4903 | static inline bool sched_debug(void) |
4904 | { | |
4905 | return false; | |
4906 | } | |
6d6bc0ad | 4907 | #endif /* CONFIG_SCHED_DEBUG */ |
1da177e4 | 4908 | |
1a20ff27 | 4909 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 | 4910 | { |
758b2cdc | 4911 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
245af2c7 SS |
4912 | return 1; |
4913 | ||
4914 | /* Following flags need at least 2 groups */ | |
4915 | if (sd->flags & (SD_LOAD_BALANCE | | |
4916 | SD_BALANCE_NEWIDLE | | |
4917 | SD_BALANCE_FORK | | |
89c4710e SS |
4918 | SD_BALANCE_EXEC | |
4919 | SD_SHARE_CPUPOWER | | |
4920 | SD_SHARE_PKG_RESOURCES)) { | |
245af2c7 SS |
4921 | if (sd->groups != sd->groups->next) |
4922 | return 0; | |
4923 | } | |
4924 | ||
4925 | /* Following flags don't use groups */ | |
c88d5910 | 4926 | if (sd->flags & (SD_WAKE_AFFINE)) |
245af2c7 SS |
4927 | return 0; |
4928 | ||
4929 | return 1; | |
4930 | } | |
4931 | ||
48f24c4d IM |
4932 | static int |
4933 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
4934 | { |
4935 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
4936 | ||
4937 | if (sd_degenerate(parent)) | |
4938 | return 1; | |
4939 | ||
758b2cdc | 4940 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
245af2c7 SS |
4941 | return 0; |
4942 | ||
245af2c7 SS |
4943 | /* Flags needing groups don't count if only 1 group in parent */ |
4944 | if (parent->groups == parent->groups->next) { | |
4945 | pflags &= ~(SD_LOAD_BALANCE | | |
4946 | SD_BALANCE_NEWIDLE | | |
4947 | SD_BALANCE_FORK | | |
89c4710e SS |
4948 | SD_BALANCE_EXEC | |
4949 | SD_SHARE_CPUPOWER | | |
10866e62 PZ |
4950 | SD_SHARE_PKG_RESOURCES | |
4951 | SD_PREFER_SIBLING); | |
5436499e KC |
4952 | if (nr_node_ids == 1) |
4953 | pflags &= ~SD_SERIALIZE; | |
245af2c7 SS |
4954 | } |
4955 | if (~cflags & pflags) | |
4956 | return 0; | |
4957 | ||
4958 | return 1; | |
4959 | } | |
4960 | ||
dce840a0 | 4961 | static void free_rootdomain(struct rcu_head *rcu) |
c6c4927b | 4962 | { |
dce840a0 | 4963 | struct root_domain *rd = container_of(rcu, struct root_domain, rcu); |
047106ad | 4964 | |
68e74568 | 4965 | cpupri_cleanup(&rd->cpupri); |
c6c4927b RR |
4966 | free_cpumask_var(rd->rto_mask); |
4967 | free_cpumask_var(rd->online); | |
4968 | free_cpumask_var(rd->span); | |
4969 | kfree(rd); | |
4970 | } | |
4971 | ||
57d885fe GH |
4972 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
4973 | { | |
a0490fa3 | 4974 | struct root_domain *old_rd = NULL; |
57d885fe | 4975 | unsigned long flags; |
57d885fe | 4976 | |
05fa785c | 4977 | raw_spin_lock_irqsave(&rq->lock, flags); |
57d885fe GH |
4978 | |
4979 | if (rq->rd) { | |
a0490fa3 | 4980 | old_rd = rq->rd; |
57d885fe | 4981 | |
c6c4927b | 4982 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
1f11eb6a | 4983 | set_rq_offline(rq); |
57d885fe | 4984 | |
c6c4927b | 4985 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
dc938520 | 4986 | |
a0490fa3 IM |
4987 | /* |
4988 | * If we dont want to free the old_rt yet then | |
4989 | * set old_rd to NULL to skip the freeing later | |
4990 | * in this function: | |
4991 | */ | |
4992 | if (!atomic_dec_and_test(&old_rd->refcount)) | |
4993 | old_rd = NULL; | |
57d885fe GH |
4994 | } |
4995 | ||
4996 | atomic_inc(&rd->refcount); | |
4997 | rq->rd = rd; | |
4998 | ||
c6c4927b | 4999 | cpumask_set_cpu(rq->cpu, rd->span); |
00aec93d | 5000 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
1f11eb6a | 5001 | set_rq_online(rq); |
57d885fe | 5002 | |
05fa785c | 5003 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
a0490fa3 IM |
5004 | |
5005 | if (old_rd) | |
dce840a0 | 5006 | call_rcu_sched(&old_rd->rcu, free_rootdomain); |
57d885fe GH |
5007 | } |
5008 | ||
68c38fc3 | 5009 | static int init_rootdomain(struct root_domain *rd) |
57d885fe GH |
5010 | { |
5011 | memset(rd, 0, sizeof(*rd)); | |
5012 | ||
68c38fc3 | 5013 | if (!alloc_cpumask_var(&rd->span, GFP_KERNEL)) |
0c910d28 | 5014 | goto out; |
68c38fc3 | 5015 | if (!alloc_cpumask_var(&rd->online, GFP_KERNEL)) |
c6c4927b | 5016 | goto free_span; |
68c38fc3 | 5017 | if (!alloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) |
c6c4927b | 5018 | goto free_online; |
6e0534f2 | 5019 | |
68c38fc3 | 5020 | if (cpupri_init(&rd->cpupri) != 0) |
68e74568 | 5021 | goto free_rto_mask; |
c6c4927b | 5022 | return 0; |
6e0534f2 | 5023 | |
68e74568 RR |
5024 | free_rto_mask: |
5025 | free_cpumask_var(rd->rto_mask); | |
c6c4927b RR |
5026 | free_online: |
5027 | free_cpumask_var(rd->online); | |
5028 | free_span: | |
5029 | free_cpumask_var(rd->span); | |
0c910d28 | 5030 | out: |
c6c4927b | 5031 | return -ENOMEM; |
57d885fe GH |
5032 | } |
5033 | ||
029632fb PZ |
5034 | /* |
5035 | * By default the system creates a single root-domain with all cpus as | |
5036 | * members (mimicking the global state we have today). | |
5037 | */ | |
5038 | struct root_domain def_root_domain; | |
5039 | ||
57d885fe GH |
5040 | static void init_defrootdomain(void) |
5041 | { | |
68c38fc3 | 5042 | init_rootdomain(&def_root_domain); |
c6c4927b | 5043 | |
57d885fe GH |
5044 | atomic_set(&def_root_domain.refcount, 1); |
5045 | } | |
5046 | ||
dc938520 | 5047 | static struct root_domain *alloc_rootdomain(void) |
57d885fe GH |
5048 | { |
5049 | struct root_domain *rd; | |
5050 | ||
5051 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); | |
5052 | if (!rd) | |
5053 | return NULL; | |
5054 | ||
68c38fc3 | 5055 | if (init_rootdomain(rd) != 0) { |
c6c4927b RR |
5056 | kfree(rd); |
5057 | return NULL; | |
5058 | } | |
57d885fe GH |
5059 | |
5060 | return rd; | |
5061 | } | |
5062 | ||
e3589f6c PZ |
5063 | static void free_sched_groups(struct sched_group *sg, int free_sgp) |
5064 | { | |
5065 | struct sched_group *tmp, *first; | |
5066 | ||
5067 | if (!sg) | |
5068 | return; | |
5069 | ||
5070 | first = sg; | |
5071 | do { | |
5072 | tmp = sg->next; | |
5073 | ||
5074 | if (free_sgp && atomic_dec_and_test(&sg->sgp->ref)) | |
5075 | kfree(sg->sgp); | |
5076 | ||
5077 | kfree(sg); | |
5078 | sg = tmp; | |
5079 | } while (sg != first); | |
5080 | } | |
5081 | ||
dce840a0 PZ |
5082 | static void free_sched_domain(struct rcu_head *rcu) |
5083 | { | |
5084 | struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); | |
e3589f6c PZ |
5085 | |
5086 | /* | |
5087 | * If its an overlapping domain it has private groups, iterate and | |
5088 | * nuke them all. | |
5089 | */ | |
5090 | if (sd->flags & SD_OVERLAP) { | |
5091 | free_sched_groups(sd->groups, 1); | |
5092 | } else if (atomic_dec_and_test(&sd->groups->ref)) { | |
9c3f75cb | 5093 | kfree(sd->groups->sgp); |
dce840a0 | 5094 | kfree(sd->groups); |
9c3f75cb | 5095 | } |
dce840a0 PZ |
5096 | kfree(sd); |
5097 | } | |
5098 | ||
5099 | static void destroy_sched_domain(struct sched_domain *sd, int cpu) | |
5100 | { | |
5101 | call_rcu(&sd->rcu, free_sched_domain); | |
5102 | } | |
5103 | ||
5104 | static void destroy_sched_domains(struct sched_domain *sd, int cpu) | |
5105 | { | |
5106 | for (; sd; sd = sd->parent) | |
5107 | destroy_sched_domain(sd, cpu); | |
5108 | } | |
5109 | ||
518cd623 PZ |
5110 | /* |
5111 | * Keep a special pointer to the highest sched_domain that has | |
5112 | * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this | |
5113 | * allows us to avoid some pointer chasing select_idle_sibling(). | |
5114 | * | |
5115 | * Also keep a unique ID per domain (we use the first cpu number in | |
5116 | * the cpumask of the domain), this allows us to quickly tell if | |
39be3501 | 5117 | * two cpus are in the same cache domain, see cpus_share_cache(). |
518cd623 PZ |
5118 | */ |
5119 | DEFINE_PER_CPU(struct sched_domain *, sd_llc); | |
7d9ffa89 | 5120 | DEFINE_PER_CPU(int, sd_llc_size); |
518cd623 PZ |
5121 | DEFINE_PER_CPU(int, sd_llc_id); |
5122 | ||
5123 | static void update_top_cache_domain(int cpu) | |
5124 | { | |
5125 | struct sched_domain *sd; | |
5126 | int id = cpu; | |
7d9ffa89 | 5127 | int size = 1; |
518cd623 PZ |
5128 | |
5129 | sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); | |
7d9ffa89 | 5130 | if (sd) { |
518cd623 | 5131 | id = cpumask_first(sched_domain_span(sd)); |
7d9ffa89 PZ |
5132 | size = cpumask_weight(sched_domain_span(sd)); |
5133 | } | |
518cd623 PZ |
5134 | |
5135 | rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); | |
7d9ffa89 | 5136 | per_cpu(sd_llc_size, cpu) = size; |
518cd623 PZ |
5137 | per_cpu(sd_llc_id, cpu) = id; |
5138 | } | |
5139 | ||
1da177e4 | 5140 | /* |
0eab9146 | 5141 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
1da177e4 LT |
5142 | * hold the hotplug lock. |
5143 | */ | |
0eab9146 IM |
5144 | static void |
5145 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) | |
1da177e4 | 5146 | { |
70b97a7f | 5147 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
5148 | struct sched_domain *tmp; |
5149 | ||
5150 | /* Remove the sched domains which do not contribute to scheduling. */ | |
f29c9b1c | 5151 | for (tmp = sd; tmp; ) { |
245af2c7 SS |
5152 | struct sched_domain *parent = tmp->parent; |
5153 | if (!parent) | |
5154 | break; | |
f29c9b1c | 5155 | |
1a848870 | 5156 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 5157 | tmp->parent = parent->parent; |
1a848870 SS |
5158 | if (parent->parent) |
5159 | parent->parent->child = tmp; | |
10866e62 PZ |
5160 | /* |
5161 | * Transfer SD_PREFER_SIBLING down in case of a | |
5162 | * degenerate parent; the spans match for this | |
5163 | * so the property transfers. | |
5164 | */ | |
5165 | if (parent->flags & SD_PREFER_SIBLING) | |
5166 | tmp->flags |= SD_PREFER_SIBLING; | |
dce840a0 | 5167 | destroy_sched_domain(parent, cpu); |
f29c9b1c LZ |
5168 | } else |
5169 | tmp = tmp->parent; | |
245af2c7 SS |
5170 | } |
5171 | ||
1a848870 | 5172 | if (sd && sd_degenerate(sd)) { |
dce840a0 | 5173 | tmp = sd; |
245af2c7 | 5174 | sd = sd->parent; |
dce840a0 | 5175 | destroy_sched_domain(tmp, cpu); |
1a848870 SS |
5176 | if (sd) |
5177 | sd->child = NULL; | |
5178 | } | |
1da177e4 | 5179 | |
4cb98839 | 5180 | sched_domain_debug(sd, cpu); |
1da177e4 | 5181 | |
57d885fe | 5182 | rq_attach_root(rq, rd); |
dce840a0 | 5183 | tmp = rq->sd; |
674311d5 | 5184 | rcu_assign_pointer(rq->sd, sd); |
dce840a0 | 5185 | destroy_sched_domains(tmp, cpu); |
518cd623 PZ |
5186 | |
5187 | update_top_cache_domain(cpu); | |
1da177e4 LT |
5188 | } |
5189 | ||
5190 | /* cpus with isolated domains */ | |
dcc30a35 | 5191 | static cpumask_var_t cpu_isolated_map; |
1da177e4 LT |
5192 | |
5193 | /* Setup the mask of cpus configured for isolated domains */ | |
5194 | static int __init isolated_cpu_setup(char *str) | |
5195 | { | |
bdddd296 | 5196 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
968ea6d8 | 5197 | cpulist_parse(str, cpu_isolated_map); |
1da177e4 LT |
5198 | return 1; |
5199 | } | |
5200 | ||
8927f494 | 5201 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 | 5202 | |
d3081f52 PZ |
5203 | static const struct cpumask *cpu_cpu_mask(int cpu) |
5204 | { | |
5205 | return cpumask_of_node(cpu_to_node(cpu)); | |
5206 | } | |
5207 | ||
dce840a0 PZ |
5208 | struct sd_data { |
5209 | struct sched_domain **__percpu sd; | |
5210 | struct sched_group **__percpu sg; | |
9c3f75cb | 5211 | struct sched_group_power **__percpu sgp; |
dce840a0 PZ |
5212 | }; |
5213 | ||
49a02c51 | 5214 | struct s_data { |
21d42ccf | 5215 | struct sched_domain ** __percpu sd; |
49a02c51 AH |
5216 | struct root_domain *rd; |
5217 | }; | |
5218 | ||
2109b99e | 5219 | enum s_alloc { |
2109b99e | 5220 | sa_rootdomain, |
21d42ccf | 5221 | sa_sd, |
dce840a0 | 5222 | sa_sd_storage, |
2109b99e AH |
5223 | sa_none, |
5224 | }; | |
5225 | ||
54ab4ff4 PZ |
5226 | struct sched_domain_topology_level; |
5227 | ||
5228 | typedef struct sched_domain *(*sched_domain_init_f)(struct sched_domain_topology_level *tl, int cpu); | |
eb7a74e6 PZ |
5229 | typedef const struct cpumask *(*sched_domain_mask_f)(int cpu); |
5230 | ||
e3589f6c PZ |
5231 | #define SDTL_OVERLAP 0x01 |
5232 | ||
eb7a74e6 | 5233 | struct sched_domain_topology_level { |
2c402dc3 PZ |
5234 | sched_domain_init_f init; |
5235 | sched_domain_mask_f mask; | |
e3589f6c | 5236 | int flags; |
cb83b629 | 5237 | int numa_level; |
54ab4ff4 | 5238 | struct sd_data data; |
eb7a74e6 PZ |
5239 | }; |
5240 | ||
c1174876 PZ |
5241 | /* |
5242 | * Build an iteration mask that can exclude certain CPUs from the upwards | |
5243 | * domain traversal. | |
5244 | * | |
5245 | * Asymmetric node setups can result in situations where the domain tree is of | |
5246 | * unequal depth, make sure to skip domains that already cover the entire | |
5247 | * range. | |
5248 | * | |
5249 | * In that case build_sched_domains() will have terminated the iteration early | |
5250 | * and our sibling sd spans will be empty. Domains should always include the | |
5251 | * cpu they're built on, so check that. | |
5252 | * | |
5253 | */ | |
5254 | static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) | |
5255 | { | |
5256 | const struct cpumask *span = sched_domain_span(sd); | |
5257 | struct sd_data *sdd = sd->private; | |
5258 | struct sched_domain *sibling; | |
5259 | int i; | |
5260 | ||
5261 | for_each_cpu(i, span) { | |
5262 | sibling = *per_cpu_ptr(sdd->sd, i); | |
5263 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) | |
5264 | continue; | |
5265 | ||
5266 | cpumask_set_cpu(i, sched_group_mask(sg)); | |
5267 | } | |
5268 | } | |
5269 | ||
5270 | /* | |
5271 | * Return the canonical balance cpu for this group, this is the first cpu | |
5272 | * of this group that's also in the iteration mask. | |
5273 | */ | |
5274 | int group_balance_cpu(struct sched_group *sg) | |
5275 | { | |
5276 | return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); | |
5277 | } | |
5278 | ||
e3589f6c PZ |
5279 | static int |
5280 | build_overlap_sched_groups(struct sched_domain *sd, int cpu) | |
5281 | { | |
5282 | struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; | |
5283 | const struct cpumask *span = sched_domain_span(sd); | |
5284 | struct cpumask *covered = sched_domains_tmpmask; | |
5285 | struct sd_data *sdd = sd->private; | |
5286 | struct sched_domain *child; | |
5287 | int i; | |
5288 | ||
5289 | cpumask_clear(covered); | |
5290 | ||
5291 | for_each_cpu(i, span) { | |
5292 | struct cpumask *sg_span; | |
5293 | ||
5294 | if (cpumask_test_cpu(i, covered)) | |
5295 | continue; | |
5296 | ||
c1174876 PZ |
5297 | child = *per_cpu_ptr(sdd->sd, i); |
5298 | ||
5299 | /* See the comment near build_group_mask(). */ | |
5300 | if (!cpumask_test_cpu(i, sched_domain_span(child))) | |
5301 | continue; | |
5302 | ||
e3589f6c | 5303 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), |
4d78a223 | 5304 | GFP_KERNEL, cpu_to_node(cpu)); |
e3589f6c PZ |
5305 | |
5306 | if (!sg) | |
5307 | goto fail; | |
5308 | ||
5309 | sg_span = sched_group_cpus(sg); | |
e3589f6c PZ |
5310 | if (child->child) { |
5311 | child = child->child; | |
5312 | cpumask_copy(sg_span, sched_domain_span(child)); | |
5313 | } else | |
5314 | cpumask_set_cpu(i, sg_span); | |
5315 | ||
5316 | cpumask_or(covered, covered, sg_span); | |
5317 | ||
74a5ce20 | 5318 | sg->sgp = *per_cpu_ptr(sdd->sgp, i); |
c1174876 PZ |
5319 | if (atomic_inc_return(&sg->sgp->ref) == 1) |
5320 | build_group_mask(sd, sg); | |
5321 | ||
c3decf0d PZ |
5322 | /* |
5323 | * Initialize sgp->power such that even if we mess up the | |
5324 | * domains and no possible iteration will get us here, we won't | |
5325 | * die on a /0 trap. | |
5326 | */ | |
5327 | sg->sgp->power = SCHED_POWER_SCALE * cpumask_weight(sg_span); | |
e3589f6c | 5328 | |
c1174876 PZ |
5329 | /* |
5330 | * Make sure the first group of this domain contains the | |
5331 | * canonical balance cpu. Otherwise the sched_domain iteration | |
5332 | * breaks. See update_sg_lb_stats(). | |
5333 | */ | |
74a5ce20 | 5334 | if ((!groups && cpumask_test_cpu(cpu, sg_span)) || |
c1174876 | 5335 | group_balance_cpu(sg) == cpu) |
e3589f6c PZ |
5336 | groups = sg; |
5337 | ||
5338 | if (!first) | |
5339 | first = sg; | |
5340 | if (last) | |
5341 | last->next = sg; | |
5342 | last = sg; | |
5343 | last->next = first; | |
5344 | } | |
5345 | sd->groups = groups; | |
5346 | ||
5347 | return 0; | |
5348 | ||
5349 | fail: | |
5350 | free_sched_groups(first, 0); | |
5351 | ||
5352 | return -ENOMEM; | |
5353 | } | |
5354 | ||
dce840a0 | 5355 | static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) |
1da177e4 | 5356 | { |
dce840a0 PZ |
5357 | struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); |
5358 | struct sched_domain *child = sd->child; | |
1da177e4 | 5359 | |
dce840a0 PZ |
5360 | if (child) |
5361 | cpu = cpumask_first(sched_domain_span(child)); | |
1e9f28fa | 5362 | |
9c3f75cb | 5363 | if (sg) { |
dce840a0 | 5364 | *sg = *per_cpu_ptr(sdd->sg, cpu); |
9c3f75cb | 5365 | (*sg)->sgp = *per_cpu_ptr(sdd->sgp, cpu); |
e3589f6c | 5366 | atomic_set(&(*sg)->sgp->ref, 1); /* for claim_allocations */ |
9c3f75cb | 5367 | } |
dce840a0 PZ |
5368 | |
5369 | return cpu; | |
1e9f28fa | 5370 | } |
1e9f28fa | 5371 | |
01a08546 | 5372 | /* |
dce840a0 PZ |
5373 | * build_sched_groups will build a circular linked list of the groups |
5374 | * covered by the given span, and will set each group's ->cpumask correctly, | |
5375 | * and ->cpu_power to 0. | |
e3589f6c PZ |
5376 | * |
5377 | * Assumes the sched_domain tree is fully constructed | |
01a08546 | 5378 | */ |
e3589f6c PZ |
5379 | static int |
5380 | build_sched_groups(struct sched_domain *sd, int cpu) | |
1da177e4 | 5381 | { |
dce840a0 PZ |
5382 | struct sched_group *first = NULL, *last = NULL; |
5383 | struct sd_data *sdd = sd->private; | |
5384 | const struct cpumask *span = sched_domain_span(sd); | |
f96225fd | 5385 | struct cpumask *covered; |
dce840a0 | 5386 | int i; |
9c1cfda2 | 5387 | |
e3589f6c PZ |
5388 | get_group(cpu, sdd, &sd->groups); |
5389 | atomic_inc(&sd->groups->ref); | |
5390 | ||
0936629f | 5391 | if (cpu != cpumask_first(span)) |
e3589f6c PZ |
5392 | return 0; |
5393 | ||
f96225fd PZ |
5394 | lockdep_assert_held(&sched_domains_mutex); |
5395 | covered = sched_domains_tmpmask; | |
5396 | ||
dce840a0 | 5397 | cpumask_clear(covered); |
6711cab4 | 5398 | |
dce840a0 PZ |
5399 | for_each_cpu(i, span) { |
5400 | struct sched_group *sg; | |
cd08e923 | 5401 | int group, j; |
6711cab4 | 5402 | |
dce840a0 PZ |
5403 | if (cpumask_test_cpu(i, covered)) |
5404 | continue; | |
6711cab4 | 5405 | |
cd08e923 | 5406 | group = get_group(i, sdd, &sg); |
dce840a0 | 5407 | cpumask_clear(sched_group_cpus(sg)); |
9c3f75cb | 5408 | sg->sgp->power = 0; |
c1174876 | 5409 | cpumask_setall(sched_group_mask(sg)); |
0601a88d | 5410 | |
dce840a0 PZ |
5411 | for_each_cpu(j, span) { |
5412 | if (get_group(j, sdd, NULL) != group) | |
5413 | continue; | |
0601a88d | 5414 | |
dce840a0 PZ |
5415 | cpumask_set_cpu(j, covered); |
5416 | cpumask_set_cpu(j, sched_group_cpus(sg)); | |
5417 | } | |
0601a88d | 5418 | |
dce840a0 PZ |
5419 | if (!first) |
5420 | first = sg; | |
5421 | if (last) | |
5422 | last->next = sg; | |
5423 | last = sg; | |
5424 | } | |
5425 | last->next = first; | |
e3589f6c PZ |
5426 | |
5427 | return 0; | |
0601a88d | 5428 | } |
51888ca2 | 5429 | |
89c4710e SS |
5430 | /* |
5431 | * Initialize sched groups cpu_power. | |
5432 | * | |
5433 | * cpu_power indicates the capacity of sched group, which is used while | |
5434 | * distributing the load between different sched groups in a sched domain. | |
5435 | * Typically cpu_power for all the groups in a sched domain will be same unless | |
5436 | * there are asymmetries in the topology. If there are asymmetries, group | |
5437 | * having more cpu_power will pickup more load compared to the group having | |
5438 | * less cpu_power. | |
89c4710e SS |
5439 | */ |
5440 | static void init_sched_groups_power(int cpu, struct sched_domain *sd) | |
5441 | { | |
e3589f6c | 5442 | struct sched_group *sg = sd->groups; |
89c4710e | 5443 | |
94c95ba6 | 5444 | WARN_ON(!sg); |
e3589f6c PZ |
5445 | |
5446 | do { | |
5447 | sg->group_weight = cpumask_weight(sched_group_cpus(sg)); | |
5448 | sg = sg->next; | |
5449 | } while (sg != sd->groups); | |
89c4710e | 5450 | |
c1174876 | 5451 | if (cpu != group_balance_cpu(sg)) |
e3589f6c | 5452 | return; |
aae6d3dd | 5453 | |
d274cb30 | 5454 | update_group_power(sd, cpu); |
69e1e811 | 5455 | atomic_set(&sg->sgp->nr_busy_cpus, sg->group_weight); |
89c4710e SS |
5456 | } |
5457 | ||
029632fb PZ |
5458 | int __weak arch_sd_sibling_asym_packing(void) |
5459 | { | |
5460 | return 0*SD_ASYM_PACKING; | |
89c4710e SS |
5461 | } |
5462 | ||
7c16ec58 MT |
5463 | /* |
5464 | * Initializers for schedule domains | |
5465 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() | |
5466 | */ | |
5467 | ||
a5d8c348 IM |
5468 | #ifdef CONFIG_SCHED_DEBUG |
5469 | # define SD_INIT_NAME(sd, type) sd->name = #type | |
5470 | #else | |
5471 | # define SD_INIT_NAME(sd, type) do { } while (0) | |
5472 | #endif | |
5473 | ||
54ab4ff4 PZ |
5474 | #define SD_INIT_FUNC(type) \ |
5475 | static noinline struct sched_domain * \ | |
5476 | sd_init_##type(struct sched_domain_topology_level *tl, int cpu) \ | |
5477 | { \ | |
5478 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); \ | |
5479 | *sd = SD_##type##_INIT; \ | |
54ab4ff4 PZ |
5480 | SD_INIT_NAME(sd, type); \ |
5481 | sd->private = &tl->data; \ | |
5482 | return sd; \ | |
7c16ec58 MT |
5483 | } |
5484 | ||
5485 | SD_INIT_FUNC(CPU) | |
7c16ec58 MT |
5486 | #ifdef CONFIG_SCHED_SMT |
5487 | SD_INIT_FUNC(SIBLING) | |
5488 | #endif | |
5489 | #ifdef CONFIG_SCHED_MC | |
5490 | SD_INIT_FUNC(MC) | |
5491 | #endif | |
01a08546 HC |
5492 | #ifdef CONFIG_SCHED_BOOK |
5493 | SD_INIT_FUNC(BOOK) | |
5494 | #endif | |
7c16ec58 | 5495 | |
1d3504fc | 5496 | static int default_relax_domain_level = -1; |
60495e77 | 5497 | int sched_domain_level_max; |
1d3504fc HS |
5498 | |
5499 | static int __init setup_relax_domain_level(char *str) | |
5500 | { | |
a841f8ce DS |
5501 | if (kstrtoint(str, 0, &default_relax_domain_level)) |
5502 | pr_warn("Unable to set relax_domain_level\n"); | |
30e0e178 | 5503 | |
1d3504fc HS |
5504 | return 1; |
5505 | } | |
5506 | __setup("relax_domain_level=", setup_relax_domain_level); | |
5507 | ||
5508 | static void set_domain_attribute(struct sched_domain *sd, | |
5509 | struct sched_domain_attr *attr) | |
5510 | { | |
5511 | int request; | |
5512 | ||
5513 | if (!attr || attr->relax_domain_level < 0) { | |
5514 | if (default_relax_domain_level < 0) | |
5515 | return; | |
5516 | else | |
5517 | request = default_relax_domain_level; | |
5518 | } else | |
5519 | request = attr->relax_domain_level; | |
5520 | if (request < sd->level) { | |
5521 | /* turn off idle balance on this domain */ | |
c88d5910 | 5522 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
5523 | } else { |
5524 | /* turn on idle balance on this domain */ | |
c88d5910 | 5525 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
5526 | } |
5527 | } | |
5528 | ||
54ab4ff4 PZ |
5529 | static void __sdt_free(const struct cpumask *cpu_map); |
5530 | static int __sdt_alloc(const struct cpumask *cpu_map); | |
5531 | ||
2109b99e AH |
5532 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
5533 | const struct cpumask *cpu_map) | |
5534 | { | |
5535 | switch (what) { | |
2109b99e | 5536 | case sa_rootdomain: |
822ff793 PZ |
5537 | if (!atomic_read(&d->rd->refcount)) |
5538 | free_rootdomain(&d->rd->rcu); /* fall through */ | |
21d42ccf PZ |
5539 | case sa_sd: |
5540 | free_percpu(d->sd); /* fall through */ | |
dce840a0 | 5541 | case sa_sd_storage: |
54ab4ff4 | 5542 | __sdt_free(cpu_map); /* fall through */ |
2109b99e AH |
5543 | case sa_none: |
5544 | break; | |
5545 | } | |
5546 | } | |
3404c8d9 | 5547 | |
2109b99e AH |
5548 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
5549 | const struct cpumask *cpu_map) | |
5550 | { | |
dce840a0 PZ |
5551 | memset(d, 0, sizeof(*d)); |
5552 | ||
54ab4ff4 PZ |
5553 | if (__sdt_alloc(cpu_map)) |
5554 | return sa_sd_storage; | |
dce840a0 PZ |
5555 | d->sd = alloc_percpu(struct sched_domain *); |
5556 | if (!d->sd) | |
5557 | return sa_sd_storage; | |
2109b99e | 5558 | d->rd = alloc_rootdomain(); |
dce840a0 | 5559 | if (!d->rd) |
21d42ccf | 5560 | return sa_sd; |
2109b99e AH |
5561 | return sa_rootdomain; |
5562 | } | |
57d885fe | 5563 | |
dce840a0 PZ |
5564 | /* |
5565 | * NULL the sd_data elements we've used to build the sched_domain and | |
5566 | * sched_group structure so that the subsequent __free_domain_allocs() | |
5567 | * will not free the data we're using. | |
5568 | */ | |
5569 | static void claim_allocations(int cpu, struct sched_domain *sd) | |
5570 | { | |
5571 | struct sd_data *sdd = sd->private; | |
dce840a0 PZ |
5572 | |
5573 | WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); | |
5574 | *per_cpu_ptr(sdd->sd, cpu) = NULL; | |
5575 | ||
e3589f6c | 5576 | if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) |
dce840a0 | 5577 | *per_cpu_ptr(sdd->sg, cpu) = NULL; |
e3589f6c PZ |
5578 | |
5579 | if (atomic_read(&(*per_cpu_ptr(sdd->sgp, cpu))->ref)) | |
9c3f75cb | 5580 | *per_cpu_ptr(sdd->sgp, cpu) = NULL; |
dce840a0 PZ |
5581 | } |
5582 | ||
2c402dc3 PZ |
5583 | #ifdef CONFIG_SCHED_SMT |
5584 | static const struct cpumask *cpu_smt_mask(int cpu) | |
7f4588f3 | 5585 | { |
2c402dc3 | 5586 | return topology_thread_cpumask(cpu); |
3bd65a80 | 5587 | } |
2c402dc3 | 5588 | #endif |
7f4588f3 | 5589 | |
d069b916 PZ |
5590 | /* |
5591 | * Topology list, bottom-up. | |
5592 | */ | |
2c402dc3 | 5593 | static struct sched_domain_topology_level default_topology[] = { |
d069b916 PZ |
5594 | #ifdef CONFIG_SCHED_SMT |
5595 | { sd_init_SIBLING, cpu_smt_mask, }, | |
01a08546 | 5596 | #endif |
1e9f28fa | 5597 | #ifdef CONFIG_SCHED_MC |
2c402dc3 | 5598 | { sd_init_MC, cpu_coregroup_mask, }, |
1e9f28fa | 5599 | #endif |
d069b916 PZ |
5600 | #ifdef CONFIG_SCHED_BOOK |
5601 | { sd_init_BOOK, cpu_book_mask, }, | |
5602 | #endif | |
5603 | { sd_init_CPU, cpu_cpu_mask, }, | |
eb7a74e6 PZ |
5604 | { NULL, }, |
5605 | }; | |
5606 | ||
5607 | static struct sched_domain_topology_level *sched_domain_topology = default_topology; | |
5608 | ||
27723a68 VK |
5609 | #define for_each_sd_topology(tl) \ |
5610 | for (tl = sched_domain_topology; tl->init; tl++) | |
5611 | ||
cb83b629 PZ |
5612 | #ifdef CONFIG_NUMA |
5613 | ||
5614 | static int sched_domains_numa_levels; | |
cb83b629 PZ |
5615 | static int *sched_domains_numa_distance; |
5616 | static struct cpumask ***sched_domains_numa_masks; | |
5617 | static int sched_domains_curr_level; | |
5618 | ||
cb83b629 PZ |
5619 | static inline int sd_local_flags(int level) |
5620 | { | |
10717dcd | 5621 | if (sched_domains_numa_distance[level] > RECLAIM_DISTANCE) |
cb83b629 PZ |
5622 | return 0; |
5623 | ||
5624 | return SD_BALANCE_EXEC | SD_BALANCE_FORK | SD_WAKE_AFFINE; | |
5625 | } | |
5626 | ||
5627 | static struct sched_domain * | |
5628 | sd_numa_init(struct sched_domain_topology_level *tl, int cpu) | |
5629 | { | |
5630 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); | |
5631 | int level = tl->numa_level; | |
5632 | int sd_weight = cpumask_weight( | |
5633 | sched_domains_numa_masks[level][cpu_to_node(cpu)]); | |
5634 | ||
5635 | *sd = (struct sched_domain){ | |
5636 | .min_interval = sd_weight, | |
5637 | .max_interval = 2*sd_weight, | |
5638 | .busy_factor = 32, | |
870a0bb5 | 5639 | .imbalance_pct = 125, |
cb83b629 PZ |
5640 | .cache_nice_tries = 2, |
5641 | .busy_idx = 3, | |
5642 | .idle_idx = 2, | |
5643 | .newidle_idx = 0, | |
5644 | .wake_idx = 0, | |
5645 | .forkexec_idx = 0, | |
5646 | ||
5647 | .flags = 1*SD_LOAD_BALANCE | |
5648 | | 1*SD_BALANCE_NEWIDLE | |
5649 | | 0*SD_BALANCE_EXEC | |
5650 | | 0*SD_BALANCE_FORK | |
5651 | | 0*SD_BALANCE_WAKE | |
5652 | | 0*SD_WAKE_AFFINE | |
cb83b629 | 5653 | | 0*SD_SHARE_CPUPOWER |
cb83b629 PZ |
5654 | | 0*SD_SHARE_PKG_RESOURCES |
5655 | | 1*SD_SERIALIZE | |
5656 | | 0*SD_PREFER_SIBLING | |
5657 | | sd_local_flags(level) | |
5658 | , | |
5659 | .last_balance = jiffies, | |
5660 | .balance_interval = sd_weight, | |
5661 | }; | |
5662 | SD_INIT_NAME(sd, NUMA); | |
5663 | sd->private = &tl->data; | |
5664 | ||
5665 | /* | |
5666 | * Ugly hack to pass state to sd_numa_mask()... | |
5667 | */ | |
5668 | sched_domains_curr_level = tl->numa_level; | |
5669 | ||
5670 | return sd; | |
5671 | } | |
5672 | ||
5673 | static const struct cpumask *sd_numa_mask(int cpu) | |
5674 | { | |
5675 | return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; | |
5676 | } | |
5677 | ||
d039ac60 PZ |
5678 | static void sched_numa_warn(const char *str) |
5679 | { | |
5680 | static int done = false; | |
5681 | int i,j; | |
5682 | ||
5683 | if (done) | |
5684 | return; | |
5685 | ||
5686 | done = true; | |
5687 | ||
5688 | printk(KERN_WARNING "ERROR: %s\n\n", str); | |
5689 | ||
5690 | for (i = 0; i < nr_node_ids; i++) { | |
5691 | printk(KERN_WARNING " "); | |
5692 | for (j = 0; j < nr_node_ids; j++) | |
5693 | printk(KERN_CONT "%02d ", node_distance(i,j)); | |
5694 | printk(KERN_CONT "\n"); | |
5695 | } | |
5696 | printk(KERN_WARNING "\n"); | |
5697 | } | |
5698 | ||
5699 | static bool find_numa_distance(int distance) | |
5700 | { | |
5701 | int i; | |
5702 | ||
5703 | if (distance == node_distance(0, 0)) | |
5704 | return true; | |
5705 | ||
5706 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
5707 | if (sched_domains_numa_distance[i] == distance) | |
5708 | return true; | |
5709 | } | |
5710 | ||
5711 | return false; | |
5712 | } | |
5713 | ||
cb83b629 PZ |
5714 | static void sched_init_numa(void) |
5715 | { | |
5716 | int next_distance, curr_distance = node_distance(0, 0); | |
5717 | struct sched_domain_topology_level *tl; | |
5718 | int level = 0; | |
5719 | int i, j, k; | |
5720 | ||
cb83b629 PZ |
5721 | sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); |
5722 | if (!sched_domains_numa_distance) | |
5723 | return; | |
5724 | ||
5725 | /* | |
5726 | * O(nr_nodes^2) deduplicating selection sort -- in order to find the | |
5727 | * unique distances in the node_distance() table. | |
5728 | * | |
5729 | * Assumes node_distance(0,j) includes all distances in | |
5730 | * node_distance(i,j) in order to avoid cubic time. | |
cb83b629 PZ |
5731 | */ |
5732 | next_distance = curr_distance; | |
5733 | for (i = 0; i < nr_node_ids; i++) { | |
5734 | for (j = 0; j < nr_node_ids; j++) { | |
d039ac60 PZ |
5735 | for (k = 0; k < nr_node_ids; k++) { |
5736 | int distance = node_distance(i, k); | |
5737 | ||
5738 | if (distance > curr_distance && | |
5739 | (distance < next_distance || | |
5740 | next_distance == curr_distance)) | |
5741 | next_distance = distance; | |
5742 | ||
5743 | /* | |
5744 | * While not a strong assumption it would be nice to know | |
5745 | * about cases where if node A is connected to B, B is not | |
5746 | * equally connected to A. | |
5747 | */ | |
5748 | if (sched_debug() && node_distance(k, i) != distance) | |
5749 | sched_numa_warn("Node-distance not symmetric"); | |
5750 | ||
5751 | if (sched_debug() && i && !find_numa_distance(distance)) | |
5752 | sched_numa_warn("Node-0 not representative"); | |
5753 | } | |
5754 | if (next_distance != curr_distance) { | |
5755 | sched_domains_numa_distance[level++] = next_distance; | |
5756 | sched_domains_numa_levels = level; | |
5757 | curr_distance = next_distance; | |
5758 | } else break; | |
cb83b629 | 5759 | } |
d039ac60 PZ |
5760 | |
5761 | /* | |
5762 | * In case of sched_debug() we verify the above assumption. | |
5763 | */ | |
5764 | if (!sched_debug()) | |
5765 | break; | |
cb83b629 PZ |
5766 | } |
5767 | /* | |
5768 | * 'level' contains the number of unique distances, excluding the | |
5769 | * identity distance node_distance(i,i). | |
5770 | * | |
28b4a521 | 5771 | * The sched_domains_numa_distance[] array includes the actual distance |
cb83b629 PZ |
5772 | * numbers. |
5773 | */ | |
5774 | ||
5f7865f3 TC |
5775 | /* |
5776 | * Here, we should temporarily reset sched_domains_numa_levels to 0. | |
5777 | * If it fails to allocate memory for array sched_domains_numa_masks[][], | |
5778 | * the array will contain less then 'level' members. This could be | |
5779 | * dangerous when we use it to iterate array sched_domains_numa_masks[][] | |
5780 | * in other functions. | |
5781 | * | |
5782 | * We reset it to 'level' at the end of this function. | |
5783 | */ | |
5784 | sched_domains_numa_levels = 0; | |
5785 | ||
cb83b629 PZ |
5786 | sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); |
5787 | if (!sched_domains_numa_masks) | |
5788 | return; | |
5789 | ||
5790 | /* | |
5791 | * Now for each level, construct a mask per node which contains all | |
5792 | * cpus of nodes that are that many hops away from us. | |
5793 | */ | |
5794 | for (i = 0; i < level; i++) { | |
5795 | sched_domains_numa_masks[i] = | |
5796 | kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); | |
5797 | if (!sched_domains_numa_masks[i]) | |
5798 | return; | |
5799 | ||
5800 | for (j = 0; j < nr_node_ids; j++) { | |
2ea45800 | 5801 | struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); |
cb83b629 PZ |
5802 | if (!mask) |
5803 | return; | |
5804 | ||
5805 | sched_domains_numa_masks[i][j] = mask; | |
5806 | ||
5807 | for (k = 0; k < nr_node_ids; k++) { | |
dd7d8634 | 5808 | if (node_distance(j, k) > sched_domains_numa_distance[i]) |
cb83b629 PZ |
5809 | continue; |
5810 | ||
5811 | cpumask_or(mask, mask, cpumask_of_node(k)); | |
5812 | } | |
5813 | } | |
5814 | } | |
5815 | ||
5816 | tl = kzalloc((ARRAY_SIZE(default_topology) + level) * | |
5817 | sizeof(struct sched_domain_topology_level), GFP_KERNEL); | |
5818 | if (!tl) | |
5819 | return; | |
5820 | ||
5821 | /* | |
5822 | * Copy the default topology bits.. | |
5823 | */ | |
5824 | for (i = 0; default_topology[i].init; i++) | |
5825 | tl[i] = default_topology[i]; | |
5826 | ||
5827 | /* | |
5828 | * .. and append 'j' levels of NUMA goodness. | |
5829 | */ | |
5830 | for (j = 0; j < level; i++, j++) { | |
5831 | tl[i] = (struct sched_domain_topology_level){ | |
5832 | .init = sd_numa_init, | |
5833 | .mask = sd_numa_mask, | |
5834 | .flags = SDTL_OVERLAP, | |
5835 | .numa_level = j, | |
5836 | }; | |
5837 | } | |
5838 | ||
5839 | sched_domain_topology = tl; | |
5f7865f3 TC |
5840 | |
5841 | sched_domains_numa_levels = level; | |
cb83b629 | 5842 | } |
301a5cba TC |
5843 | |
5844 | static void sched_domains_numa_masks_set(int cpu) | |
5845 | { | |
5846 | int i, j; | |
5847 | int node = cpu_to_node(cpu); | |
5848 | ||
5849 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
5850 | for (j = 0; j < nr_node_ids; j++) { | |
5851 | if (node_distance(j, node) <= sched_domains_numa_distance[i]) | |
5852 | cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); | |
5853 | } | |
5854 | } | |
5855 | } | |
5856 | ||
5857 | static void sched_domains_numa_masks_clear(int cpu) | |
5858 | { | |
5859 | int i, j; | |
5860 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
5861 | for (j = 0; j < nr_node_ids; j++) | |
5862 | cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); | |
5863 | } | |
5864 | } | |
5865 | ||
5866 | /* | |
5867 | * Update sched_domains_numa_masks[level][node] array when new cpus | |
5868 | * are onlined. | |
5869 | */ | |
5870 | static int sched_domains_numa_masks_update(struct notifier_block *nfb, | |
5871 | unsigned long action, | |
5872 | void *hcpu) | |
5873 | { | |
5874 | int cpu = (long)hcpu; | |
5875 | ||
5876 | switch (action & ~CPU_TASKS_FROZEN) { | |
5877 | case CPU_ONLINE: | |
5878 | sched_domains_numa_masks_set(cpu); | |
5879 | break; | |
5880 | ||
5881 | case CPU_DEAD: | |
5882 | sched_domains_numa_masks_clear(cpu); | |
5883 | break; | |
5884 | ||
5885 | default: | |
5886 | return NOTIFY_DONE; | |
5887 | } | |
5888 | ||
5889 | return NOTIFY_OK; | |
cb83b629 PZ |
5890 | } |
5891 | #else | |
5892 | static inline void sched_init_numa(void) | |
5893 | { | |
5894 | } | |
301a5cba TC |
5895 | |
5896 | static int sched_domains_numa_masks_update(struct notifier_block *nfb, | |
5897 | unsigned long action, | |
5898 | void *hcpu) | |
5899 | { | |
5900 | return 0; | |
5901 | } | |
cb83b629 PZ |
5902 | #endif /* CONFIG_NUMA */ |
5903 | ||
54ab4ff4 PZ |
5904 | static int __sdt_alloc(const struct cpumask *cpu_map) |
5905 | { | |
5906 | struct sched_domain_topology_level *tl; | |
5907 | int j; | |
5908 | ||
27723a68 | 5909 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
5910 | struct sd_data *sdd = &tl->data; |
5911 | ||
5912 | sdd->sd = alloc_percpu(struct sched_domain *); | |
5913 | if (!sdd->sd) | |
5914 | return -ENOMEM; | |
5915 | ||
5916 | sdd->sg = alloc_percpu(struct sched_group *); | |
5917 | if (!sdd->sg) | |
5918 | return -ENOMEM; | |
5919 | ||
9c3f75cb PZ |
5920 | sdd->sgp = alloc_percpu(struct sched_group_power *); |
5921 | if (!sdd->sgp) | |
5922 | return -ENOMEM; | |
5923 | ||
54ab4ff4 PZ |
5924 | for_each_cpu(j, cpu_map) { |
5925 | struct sched_domain *sd; | |
5926 | struct sched_group *sg; | |
9c3f75cb | 5927 | struct sched_group_power *sgp; |
54ab4ff4 PZ |
5928 | |
5929 | sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), | |
5930 | GFP_KERNEL, cpu_to_node(j)); | |
5931 | if (!sd) | |
5932 | return -ENOMEM; | |
5933 | ||
5934 | *per_cpu_ptr(sdd->sd, j) = sd; | |
5935 | ||
5936 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), | |
5937 | GFP_KERNEL, cpu_to_node(j)); | |
5938 | if (!sg) | |
5939 | return -ENOMEM; | |
5940 | ||
30b4e9eb IM |
5941 | sg->next = sg; |
5942 | ||
54ab4ff4 | 5943 | *per_cpu_ptr(sdd->sg, j) = sg; |
9c3f75cb | 5944 | |
c1174876 | 5945 | sgp = kzalloc_node(sizeof(struct sched_group_power) + cpumask_size(), |
9c3f75cb PZ |
5946 | GFP_KERNEL, cpu_to_node(j)); |
5947 | if (!sgp) | |
5948 | return -ENOMEM; | |
5949 | ||
5950 | *per_cpu_ptr(sdd->sgp, j) = sgp; | |
54ab4ff4 PZ |
5951 | } |
5952 | } | |
5953 | ||
5954 | return 0; | |
5955 | } | |
5956 | ||
5957 | static void __sdt_free(const struct cpumask *cpu_map) | |
5958 | { | |
5959 | struct sched_domain_topology_level *tl; | |
5960 | int j; | |
5961 | ||
27723a68 | 5962 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
5963 | struct sd_data *sdd = &tl->data; |
5964 | ||
5965 | for_each_cpu(j, cpu_map) { | |
fb2cf2c6 | 5966 | struct sched_domain *sd; |
5967 | ||
5968 | if (sdd->sd) { | |
5969 | sd = *per_cpu_ptr(sdd->sd, j); | |
5970 | if (sd && (sd->flags & SD_OVERLAP)) | |
5971 | free_sched_groups(sd->groups, 0); | |
5972 | kfree(*per_cpu_ptr(sdd->sd, j)); | |
5973 | } | |
5974 | ||
5975 | if (sdd->sg) | |
5976 | kfree(*per_cpu_ptr(sdd->sg, j)); | |
5977 | if (sdd->sgp) | |
5978 | kfree(*per_cpu_ptr(sdd->sgp, j)); | |
54ab4ff4 PZ |
5979 | } |
5980 | free_percpu(sdd->sd); | |
fb2cf2c6 | 5981 | sdd->sd = NULL; |
54ab4ff4 | 5982 | free_percpu(sdd->sg); |
fb2cf2c6 | 5983 | sdd->sg = NULL; |
9c3f75cb | 5984 | free_percpu(sdd->sgp); |
fb2cf2c6 | 5985 | sdd->sgp = NULL; |
54ab4ff4 PZ |
5986 | } |
5987 | } | |
5988 | ||
2c402dc3 | 5989 | struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, |
4a850cbe VK |
5990 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
5991 | struct sched_domain *child, int cpu) | |
2c402dc3 | 5992 | { |
54ab4ff4 | 5993 | struct sched_domain *sd = tl->init(tl, cpu); |
2c402dc3 | 5994 | if (!sd) |
d069b916 | 5995 | return child; |
2c402dc3 | 5996 | |
2c402dc3 | 5997 | cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); |
60495e77 PZ |
5998 | if (child) { |
5999 | sd->level = child->level + 1; | |
6000 | sched_domain_level_max = max(sched_domain_level_max, sd->level); | |
d069b916 | 6001 | child->parent = sd; |
c75e0128 | 6002 | sd->child = child; |
60495e77 | 6003 | } |
a841f8ce | 6004 | set_domain_attribute(sd, attr); |
2c402dc3 PZ |
6005 | |
6006 | return sd; | |
6007 | } | |
6008 | ||
2109b99e AH |
6009 | /* |
6010 | * Build sched domains for a given set of cpus and attach the sched domains | |
6011 | * to the individual cpus | |
6012 | */ | |
dce840a0 PZ |
6013 | static int build_sched_domains(const struct cpumask *cpu_map, |
6014 | struct sched_domain_attr *attr) | |
2109b99e | 6015 | { |
1c632169 | 6016 | enum s_alloc alloc_state; |
dce840a0 | 6017 | struct sched_domain *sd; |
2109b99e | 6018 | struct s_data d; |
822ff793 | 6019 | int i, ret = -ENOMEM; |
9c1cfda2 | 6020 | |
2109b99e AH |
6021 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
6022 | if (alloc_state != sa_rootdomain) | |
6023 | goto error; | |
9c1cfda2 | 6024 | |
dce840a0 | 6025 | /* Set up domains for cpus specified by the cpu_map. */ |
abcd083a | 6026 | for_each_cpu(i, cpu_map) { |
eb7a74e6 PZ |
6027 | struct sched_domain_topology_level *tl; |
6028 | ||
3bd65a80 | 6029 | sd = NULL; |
27723a68 | 6030 | for_each_sd_topology(tl) { |
4a850cbe | 6031 | sd = build_sched_domain(tl, cpu_map, attr, sd, i); |
22da9569 VK |
6032 | if (tl == sched_domain_topology) |
6033 | *per_cpu_ptr(d.sd, i) = sd; | |
e3589f6c PZ |
6034 | if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) |
6035 | sd->flags |= SD_OVERLAP; | |
d110235d PZ |
6036 | if (cpumask_equal(cpu_map, sched_domain_span(sd))) |
6037 | break; | |
e3589f6c | 6038 | } |
dce840a0 PZ |
6039 | } |
6040 | ||
6041 | /* Build the groups for the domains */ | |
6042 | for_each_cpu(i, cpu_map) { | |
6043 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { | |
6044 | sd->span_weight = cpumask_weight(sched_domain_span(sd)); | |
e3589f6c PZ |
6045 | if (sd->flags & SD_OVERLAP) { |
6046 | if (build_overlap_sched_groups(sd, i)) | |
6047 | goto error; | |
6048 | } else { | |
6049 | if (build_sched_groups(sd, i)) | |
6050 | goto error; | |
6051 | } | |
1cf51902 | 6052 | } |
a06dadbe | 6053 | } |
9c1cfda2 | 6054 | |
1da177e4 | 6055 | /* Calculate CPU power for physical packages and nodes */ |
a9c9a9b6 PZ |
6056 | for (i = nr_cpumask_bits-1; i >= 0; i--) { |
6057 | if (!cpumask_test_cpu(i, cpu_map)) | |
6058 | continue; | |
9c1cfda2 | 6059 | |
dce840a0 PZ |
6060 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { |
6061 | claim_allocations(i, sd); | |
cd4ea6ae | 6062 | init_sched_groups_power(i, sd); |
dce840a0 | 6063 | } |
f712c0c7 | 6064 | } |
9c1cfda2 | 6065 | |
1da177e4 | 6066 | /* Attach the domains */ |
dce840a0 | 6067 | rcu_read_lock(); |
abcd083a | 6068 | for_each_cpu(i, cpu_map) { |
21d42ccf | 6069 | sd = *per_cpu_ptr(d.sd, i); |
49a02c51 | 6070 | cpu_attach_domain(sd, d.rd, i); |
1da177e4 | 6071 | } |
dce840a0 | 6072 | rcu_read_unlock(); |
51888ca2 | 6073 | |
822ff793 | 6074 | ret = 0; |
51888ca2 | 6075 | error: |
2109b99e | 6076 | __free_domain_allocs(&d, alloc_state, cpu_map); |
822ff793 | 6077 | return ret; |
1da177e4 | 6078 | } |
029190c5 | 6079 | |
acc3f5d7 | 6080 | static cpumask_var_t *doms_cur; /* current sched domains */ |
029190c5 | 6081 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
4285f594 IM |
6082 | static struct sched_domain_attr *dattr_cur; |
6083 | /* attribues of custom domains in 'doms_cur' */ | |
029190c5 PJ |
6084 | |
6085 | /* | |
6086 | * Special case: If a kmalloc of a doms_cur partition (array of | |
4212823f RR |
6087 | * cpumask) fails, then fallback to a single sched domain, |
6088 | * as determined by the single cpumask fallback_doms. | |
029190c5 | 6089 | */ |
4212823f | 6090 | static cpumask_var_t fallback_doms; |
029190c5 | 6091 | |
ee79d1bd HC |
6092 | /* |
6093 | * arch_update_cpu_topology lets virtualized architectures update the | |
6094 | * cpu core maps. It is supposed to return 1 if the topology changed | |
6095 | * or 0 if it stayed the same. | |
6096 | */ | |
6097 | int __attribute__((weak)) arch_update_cpu_topology(void) | |
22e52b07 | 6098 | { |
ee79d1bd | 6099 | return 0; |
22e52b07 HC |
6100 | } |
6101 | ||
acc3f5d7 RR |
6102 | cpumask_var_t *alloc_sched_domains(unsigned int ndoms) |
6103 | { | |
6104 | int i; | |
6105 | cpumask_var_t *doms; | |
6106 | ||
6107 | doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); | |
6108 | if (!doms) | |
6109 | return NULL; | |
6110 | for (i = 0; i < ndoms; i++) { | |
6111 | if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { | |
6112 | free_sched_domains(doms, i); | |
6113 | return NULL; | |
6114 | } | |
6115 | } | |
6116 | return doms; | |
6117 | } | |
6118 | ||
6119 | void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) | |
6120 | { | |
6121 | unsigned int i; | |
6122 | for (i = 0; i < ndoms; i++) | |
6123 | free_cpumask_var(doms[i]); | |
6124 | kfree(doms); | |
6125 | } | |
6126 | ||
1a20ff27 | 6127 | /* |
41a2d6cf | 6128 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
6129 | * For now this just excludes isolated cpus, but could be used to |
6130 | * exclude other special cases in the future. | |
1a20ff27 | 6131 | */ |
c4a8849a | 6132 | static int init_sched_domains(const struct cpumask *cpu_map) |
1a20ff27 | 6133 | { |
7378547f MM |
6134 | int err; |
6135 | ||
22e52b07 | 6136 | arch_update_cpu_topology(); |
029190c5 | 6137 | ndoms_cur = 1; |
acc3f5d7 | 6138 | doms_cur = alloc_sched_domains(ndoms_cur); |
029190c5 | 6139 | if (!doms_cur) |
acc3f5d7 RR |
6140 | doms_cur = &fallback_doms; |
6141 | cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); | |
dce840a0 | 6142 | err = build_sched_domains(doms_cur[0], NULL); |
6382bc90 | 6143 | register_sched_domain_sysctl(); |
7378547f MM |
6144 | |
6145 | return err; | |
1a20ff27 DG |
6146 | } |
6147 | ||
1a20ff27 DG |
6148 | /* |
6149 | * Detach sched domains from a group of cpus specified in cpu_map | |
6150 | * These cpus will now be attached to the NULL domain | |
6151 | */ | |
96f874e2 | 6152 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
1a20ff27 DG |
6153 | { |
6154 | int i; | |
6155 | ||
dce840a0 | 6156 | rcu_read_lock(); |
abcd083a | 6157 | for_each_cpu(i, cpu_map) |
57d885fe | 6158 | cpu_attach_domain(NULL, &def_root_domain, i); |
dce840a0 | 6159 | rcu_read_unlock(); |
1a20ff27 DG |
6160 | } |
6161 | ||
1d3504fc HS |
6162 | /* handle null as "default" */ |
6163 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, | |
6164 | struct sched_domain_attr *new, int idx_new) | |
6165 | { | |
6166 | struct sched_domain_attr tmp; | |
6167 | ||
6168 | /* fast path */ | |
6169 | if (!new && !cur) | |
6170 | return 1; | |
6171 | ||
6172 | tmp = SD_ATTR_INIT; | |
6173 | return !memcmp(cur ? (cur + idx_cur) : &tmp, | |
6174 | new ? (new + idx_new) : &tmp, | |
6175 | sizeof(struct sched_domain_attr)); | |
6176 | } | |
6177 | ||
029190c5 PJ |
6178 | /* |
6179 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 6180 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
6181 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
6182 | * It destroys each deleted domain and builds each new domain. | |
6183 | * | |
acc3f5d7 | 6184 | * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. |
41a2d6cf IM |
6185 | * The masks don't intersect (don't overlap.) We should setup one |
6186 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
6187 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
6188 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
6189 | * it as it is. | |
6190 | * | |
acc3f5d7 RR |
6191 | * The passed in 'doms_new' should be allocated using |
6192 | * alloc_sched_domains. This routine takes ownership of it and will | |
6193 | * free_sched_domains it when done with it. If the caller failed the | |
6194 | * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, | |
6195 | * and partition_sched_domains() will fallback to the single partition | |
6196 | * 'fallback_doms', it also forces the domains to be rebuilt. | |
029190c5 | 6197 | * |
96f874e2 | 6198 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
700018e0 LZ |
6199 | * ndoms_new == 0 is a special case for destroying existing domains, |
6200 | * and it will not create the default domain. | |
dfb512ec | 6201 | * |
029190c5 PJ |
6202 | * Call with hotplug lock held |
6203 | */ | |
acc3f5d7 | 6204 | void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
1d3504fc | 6205 | struct sched_domain_attr *dattr_new) |
029190c5 | 6206 | { |
dfb512ec | 6207 | int i, j, n; |
d65bd5ec | 6208 | int new_topology; |
029190c5 | 6209 | |
712555ee | 6210 | mutex_lock(&sched_domains_mutex); |
a1835615 | 6211 | |
7378547f MM |
6212 | /* always unregister in case we don't destroy any domains */ |
6213 | unregister_sched_domain_sysctl(); | |
6214 | ||
d65bd5ec HC |
6215 | /* Let architecture update cpu core mappings. */ |
6216 | new_topology = arch_update_cpu_topology(); | |
6217 | ||
dfb512ec | 6218 | n = doms_new ? ndoms_new : 0; |
029190c5 PJ |
6219 | |
6220 | /* Destroy deleted domains */ | |
6221 | for (i = 0; i < ndoms_cur; i++) { | |
d65bd5ec | 6222 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 6223 | if (cpumask_equal(doms_cur[i], doms_new[j]) |
1d3504fc | 6224 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
029190c5 PJ |
6225 | goto match1; |
6226 | } | |
6227 | /* no match - a current sched domain not in new doms_new[] */ | |
acc3f5d7 | 6228 | detach_destroy_domains(doms_cur[i]); |
029190c5 PJ |
6229 | match1: |
6230 | ; | |
6231 | } | |
6232 | ||
c8d2d47a | 6233 | n = ndoms_cur; |
e761b772 | 6234 | if (doms_new == NULL) { |
c8d2d47a | 6235 | n = 0; |
acc3f5d7 | 6236 | doms_new = &fallback_doms; |
6ad4c188 | 6237 | cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); |
faa2f98f | 6238 | WARN_ON_ONCE(dattr_new); |
e761b772 MK |
6239 | } |
6240 | ||
029190c5 PJ |
6241 | /* Build new domains */ |
6242 | for (i = 0; i < ndoms_new; i++) { | |
c8d2d47a | 6243 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 6244 | if (cpumask_equal(doms_new[i], doms_cur[j]) |
1d3504fc | 6245 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
029190c5 PJ |
6246 | goto match2; |
6247 | } | |
6248 | /* no match - add a new doms_new */ | |
dce840a0 | 6249 | build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); |
029190c5 PJ |
6250 | match2: |
6251 | ; | |
6252 | } | |
6253 | ||
6254 | /* Remember the new sched domains */ | |
acc3f5d7 RR |
6255 | if (doms_cur != &fallback_doms) |
6256 | free_sched_domains(doms_cur, ndoms_cur); | |
1d3504fc | 6257 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
029190c5 | 6258 | doms_cur = doms_new; |
1d3504fc | 6259 | dattr_cur = dattr_new; |
029190c5 | 6260 | ndoms_cur = ndoms_new; |
7378547f MM |
6261 | |
6262 | register_sched_domain_sysctl(); | |
a1835615 | 6263 | |
712555ee | 6264 | mutex_unlock(&sched_domains_mutex); |
029190c5 PJ |
6265 | } |
6266 | ||
d35be8ba SB |
6267 | static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ |
6268 | ||
1da177e4 | 6269 | /* |
3a101d05 TH |
6270 | * Update cpusets according to cpu_active mask. If cpusets are |
6271 | * disabled, cpuset_update_active_cpus() becomes a simple wrapper | |
6272 | * around partition_sched_domains(). | |
d35be8ba SB |
6273 | * |
6274 | * If we come here as part of a suspend/resume, don't touch cpusets because we | |
6275 | * want to restore it back to its original state upon resume anyway. | |
1da177e4 | 6276 | */ |
0b2e918a TH |
6277 | static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, |
6278 | void *hcpu) | |
e761b772 | 6279 | { |
d35be8ba SB |
6280 | switch (action) { |
6281 | case CPU_ONLINE_FROZEN: | |
6282 | case CPU_DOWN_FAILED_FROZEN: | |
6283 | ||
6284 | /* | |
6285 | * num_cpus_frozen tracks how many CPUs are involved in suspend | |
6286 | * resume sequence. As long as this is not the last online | |
6287 | * operation in the resume sequence, just build a single sched | |
6288 | * domain, ignoring cpusets. | |
6289 | */ | |
6290 | num_cpus_frozen--; | |
6291 | if (likely(num_cpus_frozen)) { | |
6292 | partition_sched_domains(1, NULL, NULL); | |
6293 | break; | |
6294 | } | |
6295 | ||
6296 | /* | |
6297 | * This is the last CPU online operation. So fall through and | |
6298 | * restore the original sched domains by considering the | |
6299 | * cpuset configurations. | |
6300 | */ | |
6301 | ||
e761b772 | 6302 | case CPU_ONLINE: |
6ad4c188 | 6303 | case CPU_DOWN_FAILED: |
7ddf96b0 | 6304 | cpuset_update_active_cpus(true); |
d35be8ba | 6305 | break; |
3a101d05 TH |
6306 | default: |
6307 | return NOTIFY_DONE; | |
6308 | } | |
d35be8ba | 6309 | return NOTIFY_OK; |
3a101d05 | 6310 | } |
e761b772 | 6311 | |
0b2e918a TH |
6312 | static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, |
6313 | void *hcpu) | |
3a101d05 | 6314 | { |
d35be8ba | 6315 | switch (action) { |
3a101d05 | 6316 | case CPU_DOWN_PREPARE: |
7ddf96b0 | 6317 | cpuset_update_active_cpus(false); |
d35be8ba SB |
6318 | break; |
6319 | case CPU_DOWN_PREPARE_FROZEN: | |
6320 | num_cpus_frozen++; | |
6321 | partition_sched_domains(1, NULL, NULL); | |
6322 | break; | |
e761b772 MK |
6323 | default: |
6324 | return NOTIFY_DONE; | |
6325 | } | |
d35be8ba | 6326 | return NOTIFY_OK; |
e761b772 | 6327 | } |
e761b772 | 6328 | |
1da177e4 LT |
6329 | void __init sched_init_smp(void) |
6330 | { | |
dcc30a35 RR |
6331 | cpumask_var_t non_isolated_cpus; |
6332 | ||
6333 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); | |
cb5fd13f | 6334 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
5c1e1767 | 6335 | |
cb83b629 PZ |
6336 | sched_init_numa(); |
6337 | ||
95402b38 | 6338 | get_online_cpus(); |
712555ee | 6339 | mutex_lock(&sched_domains_mutex); |
c4a8849a | 6340 | init_sched_domains(cpu_active_mask); |
dcc30a35 RR |
6341 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
6342 | if (cpumask_empty(non_isolated_cpus)) | |
6343 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); | |
712555ee | 6344 | mutex_unlock(&sched_domains_mutex); |
95402b38 | 6345 | put_online_cpus(); |
e761b772 | 6346 | |
301a5cba | 6347 | hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); |
3a101d05 TH |
6348 | hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); |
6349 | hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); | |
e761b772 | 6350 | |
b328ca18 | 6351 | init_hrtick(); |
5c1e1767 NP |
6352 | |
6353 | /* Move init over to a non-isolated CPU */ | |
dcc30a35 | 6354 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
5c1e1767 | 6355 | BUG(); |
19978ca6 | 6356 | sched_init_granularity(); |
dcc30a35 | 6357 | free_cpumask_var(non_isolated_cpus); |
4212823f | 6358 | |
0e3900e6 | 6359 | init_sched_rt_class(); |
1da177e4 LT |
6360 | } |
6361 | #else | |
6362 | void __init sched_init_smp(void) | |
6363 | { | |
19978ca6 | 6364 | sched_init_granularity(); |
1da177e4 LT |
6365 | } |
6366 | #endif /* CONFIG_SMP */ | |
6367 | ||
cd1bb94b AB |
6368 | const_debug unsigned int sysctl_timer_migration = 1; |
6369 | ||
1da177e4 LT |
6370 | int in_sched_functions(unsigned long addr) |
6371 | { | |
1da177e4 LT |
6372 | return in_lock_functions(addr) || |
6373 | (addr >= (unsigned long)__sched_text_start | |
6374 | && addr < (unsigned long)__sched_text_end); | |
6375 | } | |
6376 | ||
029632fb | 6377 | #ifdef CONFIG_CGROUP_SCHED |
27b4b931 LZ |
6378 | /* |
6379 | * Default task group. | |
6380 | * Every task in system belongs to this group at bootup. | |
6381 | */ | |
029632fb | 6382 | struct task_group root_task_group; |
35cf4e50 | 6383 | LIST_HEAD(task_groups); |
052f1dc7 | 6384 | #endif |
6f505b16 | 6385 | |
e6252c3e | 6386 | DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); |
6f505b16 | 6387 | |
1da177e4 LT |
6388 | void __init sched_init(void) |
6389 | { | |
dd41f596 | 6390 | int i, j; |
434d53b0 MT |
6391 | unsigned long alloc_size = 0, ptr; |
6392 | ||
6393 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
6394 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
6395 | #endif | |
6396 | #ifdef CONFIG_RT_GROUP_SCHED | |
6397 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
eff766a6 | 6398 | #endif |
df7c8e84 | 6399 | #ifdef CONFIG_CPUMASK_OFFSTACK |
8c083f08 | 6400 | alloc_size += num_possible_cpus() * cpumask_size(); |
434d53b0 | 6401 | #endif |
434d53b0 | 6402 | if (alloc_size) { |
36b7b6d4 | 6403 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
434d53b0 MT |
6404 | |
6405 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
07e06b01 | 6406 | root_task_group.se = (struct sched_entity **)ptr; |
434d53b0 MT |
6407 | ptr += nr_cpu_ids * sizeof(void **); |
6408 | ||
07e06b01 | 6409 | root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
434d53b0 | 6410 | ptr += nr_cpu_ids * sizeof(void **); |
eff766a6 | 6411 | |
6d6bc0ad | 6412 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
434d53b0 | 6413 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 6414 | root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
434d53b0 MT |
6415 | ptr += nr_cpu_ids * sizeof(void **); |
6416 | ||
07e06b01 | 6417 | root_task_group.rt_rq = (struct rt_rq **)ptr; |
eff766a6 PZ |
6418 | ptr += nr_cpu_ids * sizeof(void **); |
6419 | ||
6d6bc0ad | 6420 | #endif /* CONFIG_RT_GROUP_SCHED */ |
df7c8e84 RR |
6421 | #ifdef CONFIG_CPUMASK_OFFSTACK |
6422 | for_each_possible_cpu(i) { | |
e6252c3e | 6423 | per_cpu(load_balance_mask, i) = (void *)ptr; |
df7c8e84 RR |
6424 | ptr += cpumask_size(); |
6425 | } | |
6426 | #endif /* CONFIG_CPUMASK_OFFSTACK */ | |
434d53b0 | 6427 | } |
dd41f596 | 6428 | |
57d885fe GH |
6429 | #ifdef CONFIG_SMP |
6430 | init_defrootdomain(); | |
6431 | #endif | |
6432 | ||
d0b27fa7 PZ |
6433 | init_rt_bandwidth(&def_rt_bandwidth, |
6434 | global_rt_period(), global_rt_runtime()); | |
6435 | ||
6436 | #ifdef CONFIG_RT_GROUP_SCHED | |
07e06b01 | 6437 | init_rt_bandwidth(&root_task_group.rt_bandwidth, |
d0b27fa7 | 6438 | global_rt_period(), global_rt_runtime()); |
6d6bc0ad | 6439 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 6440 | |
7c941438 | 6441 | #ifdef CONFIG_CGROUP_SCHED |
07e06b01 YZ |
6442 | list_add(&root_task_group.list, &task_groups); |
6443 | INIT_LIST_HEAD(&root_task_group.children); | |
f4d6f6c2 | 6444 | INIT_LIST_HEAD(&root_task_group.siblings); |
5091faa4 | 6445 | autogroup_init(&init_task); |
54c707e9 | 6446 | |
7c941438 | 6447 | #endif /* CONFIG_CGROUP_SCHED */ |
6f505b16 | 6448 | |
0a945022 | 6449 | for_each_possible_cpu(i) { |
70b97a7f | 6450 | struct rq *rq; |
1da177e4 LT |
6451 | |
6452 | rq = cpu_rq(i); | |
05fa785c | 6453 | raw_spin_lock_init(&rq->lock); |
7897986b | 6454 | rq->nr_running = 0; |
dce48a84 TG |
6455 | rq->calc_load_active = 0; |
6456 | rq->calc_load_update = jiffies + LOAD_FREQ; | |
acb5a9ba | 6457 | init_cfs_rq(&rq->cfs); |
6f505b16 | 6458 | init_rt_rq(&rq->rt, rq); |
dd41f596 | 6459 | #ifdef CONFIG_FAIR_GROUP_SCHED |
029632fb | 6460 | root_task_group.shares = ROOT_TASK_GROUP_LOAD; |
6f505b16 | 6461 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
354d60c2 | 6462 | /* |
07e06b01 | 6463 | * How much cpu bandwidth does root_task_group get? |
354d60c2 DG |
6464 | * |
6465 | * In case of task-groups formed thr' the cgroup filesystem, it | |
6466 | * gets 100% of the cpu resources in the system. This overall | |
6467 | * system cpu resource is divided among the tasks of | |
07e06b01 | 6468 | * root_task_group and its child task-groups in a fair manner, |
354d60c2 DG |
6469 | * based on each entity's (task or task-group's) weight |
6470 | * (se->load.weight). | |
6471 | * | |
07e06b01 | 6472 | * In other words, if root_task_group has 10 tasks of weight |
354d60c2 DG |
6473 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
6474 | * then A0's share of the cpu resource is: | |
6475 | * | |
0d905bca | 6476 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
354d60c2 | 6477 | * |
07e06b01 YZ |
6478 | * We achieve this by letting root_task_group's tasks sit |
6479 | * directly in rq->cfs (i.e root_task_group->se[] = NULL). | |
354d60c2 | 6480 | */ |
ab84d31e | 6481 | init_cfs_bandwidth(&root_task_group.cfs_bandwidth); |
07e06b01 | 6482 | init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); |
354d60c2 DG |
6483 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
6484 | ||
6485 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; | |
052f1dc7 | 6486 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 6487 | INIT_LIST_HEAD(&rq->leaf_rt_rq_list); |
07e06b01 | 6488 | init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); |
dd41f596 | 6489 | #endif |
1da177e4 | 6490 | |
dd41f596 IM |
6491 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
6492 | rq->cpu_load[j] = 0; | |
fdf3e95d VP |
6493 | |
6494 | rq->last_load_update_tick = jiffies; | |
6495 | ||
1da177e4 | 6496 | #ifdef CONFIG_SMP |
41c7ce9a | 6497 | rq->sd = NULL; |
57d885fe | 6498 | rq->rd = NULL; |
1399fa78 | 6499 | rq->cpu_power = SCHED_POWER_SCALE; |
3f029d3c | 6500 | rq->post_schedule = 0; |
1da177e4 | 6501 | rq->active_balance = 0; |
dd41f596 | 6502 | rq->next_balance = jiffies; |
1da177e4 | 6503 | rq->push_cpu = 0; |
0a2966b4 | 6504 | rq->cpu = i; |
1f11eb6a | 6505 | rq->online = 0; |
eae0c9df MG |
6506 | rq->idle_stamp = 0; |
6507 | rq->avg_idle = 2*sysctl_sched_migration_cost; | |
367456c7 PZ |
6508 | |
6509 | INIT_LIST_HEAD(&rq->cfs_tasks); | |
6510 | ||
dc938520 | 6511 | rq_attach_root(rq, &def_root_domain); |
3451d024 | 6512 | #ifdef CONFIG_NO_HZ_COMMON |
1c792db7 | 6513 | rq->nohz_flags = 0; |
83cd4fe2 | 6514 | #endif |
265f22a9 FW |
6515 | #ifdef CONFIG_NO_HZ_FULL |
6516 | rq->last_sched_tick = 0; | |
6517 | #endif | |
1da177e4 | 6518 | #endif |
8f4d37ec | 6519 | init_rq_hrtick(rq); |
1da177e4 | 6520 | atomic_set(&rq->nr_iowait, 0); |
1da177e4 LT |
6521 | } |
6522 | ||
2dd73a4f | 6523 | set_load_weight(&init_task); |
b50f60ce | 6524 | |
e107be36 AK |
6525 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
6526 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
6527 | #endif | |
6528 | ||
b50f60ce | 6529 | #ifdef CONFIG_RT_MUTEXES |
732375c6 | 6530 | plist_head_init(&init_task.pi_waiters); |
b50f60ce HC |
6531 | #endif |
6532 | ||
1da177e4 LT |
6533 | /* |
6534 | * The boot idle thread does lazy MMU switching as well: | |
6535 | */ | |
6536 | atomic_inc(&init_mm.mm_count); | |
6537 | enter_lazy_tlb(&init_mm, current); | |
6538 | ||
6539 | /* | |
6540 | * Make us the idle thread. Technically, schedule() should not be | |
6541 | * called from this thread, however somewhere below it might be, | |
6542 | * but because we are the idle thread, we just pick up running again | |
6543 | * when this runqueue becomes "idle". | |
6544 | */ | |
6545 | init_idle(current, smp_processor_id()); | |
dce48a84 TG |
6546 | |
6547 | calc_load_update = jiffies + LOAD_FREQ; | |
6548 | ||
dd41f596 IM |
6549 | /* |
6550 | * During early bootup we pretend to be a normal task: | |
6551 | */ | |
6552 | current->sched_class = &fair_sched_class; | |
6892b75e | 6553 | |
bf4d83f6 | 6554 | #ifdef CONFIG_SMP |
4cb98839 | 6555 | zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); |
bdddd296 RR |
6556 | /* May be allocated at isolcpus cmdline parse time */ |
6557 | if (cpu_isolated_map == NULL) | |
6558 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); | |
29d5e047 | 6559 | idle_thread_set_boot_cpu(); |
029632fb PZ |
6560 | #endif |
6561 | init_sched_fair_class(); | |
6a7b3dc3 | 6562 | |
6892b75e | 6563 | scheduler_running = 1; |
1da177e4 LT |
6564 | } |
6565 | ||
d902db1e | 6566 | #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
e4aafea2 FW |
6567 | static inline int preempt_count_equals(int preempt_offset) |
6568 | { | |
234da7bc | 6569 | int nested = (preempt_count() & ~PREEMPT_ACTIVE) + rcu_preempt_depth(); |
e4aafea2 | 6570 | |
4ba8216c | 6571 | return (nested == preempt_offset); |
e4aafea2 FW |
6572 | } |
6573 | ||
d894837f | 6574 | void __might_sleep(const char *file, int line, int preempt_offset) |
1da177e4 | 6575 | { |
1da177e4 LT |
6576 | static unsigned long prev_jiffy; /* ratelimiting */ |
6577 | ||
b3fbab05 | 6578 | rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ |
e4aafea2 FW |
6579 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) || |
6580 | system_state != SYSTEM_RUNNING || oops_in_progress) | |
aef745fc IM |
6581 | return; |
6582 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
6583 | return; | |
6584 | prev_jiffy = jiffies; | |
6585 | ||
3df0fc5b PZ |
6586 | printk(KERN_ERR |
6587 | "BUG: sleeping function called from invalid context at %s:%d\n", | |
6588 | file, line); | |
6589 | printk(KERN_ERR | |
6590 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", | |
6591 | in_atomic(), irqs_disabled(), | |
6592 | current->pid, current->comm); | |
aef745fc IM |
6593 | |
6594 | debug_show_held_locks(current); | |
6595 | if (irqs_disabled()) | |
6596 | print_irqtrace_events(current); | |
6597 | dump_stack(); | |
1da177e4 LT |
6598 | } |
6599 | EXPORT_SYMBOL(__might_sleep); | |
6600 | #endif | |
6601 | ||
6602 | #ifdef CONFIG_MAGIC_SYSRQ | |
3a5e4dc1 AK |
6603 | static void normalize_task(struct rq *rq, struct task_struct *p) |
6604 | { | |
da7a735e PZ |
6605 | const struct sched_class *prev_class = p->sched_class; |
6606 | int old_prio = p->prio; | |
3a5e4dc1 | 6607 | int on_rq; |
3e51f33f | 6608 | |
fd2f4419 | 6609 | on_rq = p->on_rq; |
3a5e4dc1 | 6610 | if (on_rq) |
4ca9b72b | 6611 | dequeue_task(rq, p, 0); |
3a5e4dc1 AK |
6612 | __setscheduler(rq, p, SCHED_NORMAL, 0); |
6613 | if (on_rq) { | |
4ca9b72b | 6614 | enqueue_task(rq, p, 0); |
3a5e4dc1 AK |
6615 | resched_task(rq->curr); |
6616 | } | |
da7a735e PZ |
6617 | |
6618 | check_class_changed(rq, p, prev_class, old_prio); | |
3a5e4dc1 AK |
6619 | } |
6620 | ||
1da177e4 LT |
6621 | void normalize_rt_tasks(void) |
6622 | { | |
a0f98a1c | 6623 | struct task_struct *g, *p; |
1da177e4 | 6624 | unsigned long flags; |
70b97a7f | 6625 | struct rq *rq; |
1da177e4 | 6626 | |
4cf5d77a | 6627 | read_lock_irqsave(&tasklist_lock, flags); |
a0f98a1c | 6628 | do_each_thread(g, p) { |
178be793 IM |
6629 | /* |
6630 | * Only normalize user tasks: | |
6631 | */ | |
6632 | if (!p->mm) | |
6633 | continue; | |
6634 | ||
6cfb0d5d | 6635 | p->se.exec_start = 0; |
6cfb0d5d | 6636 | #ifdef CONFIG_SCHEDSTATS |
41acab88 LDM |
6637 | p->se.statistics.wait_start = 0; |
6638 | p->se.statistics.sleep_start = 0; | |
6639 | p->se.statistics.block_start = 0; | |
6cfb0d5d | 6640 | #endif |
dd41f596 IM |
6641 | |
6642 | if (!rt_task(p)) { | |
6643 | /* | |
6644 | * Renice negative nice level userspace | |
6645 | * tasks back to 0: | |
6646 | */ | |
6647 | if (TASK_NICE(p) < 0 && p->mm) | |
6648 | set_user_nice(p, 0); | |
1da177e4 | 6649 | continue; |
dd41f596 | 6650 | } |
1da177e4 | 6651 | |
1d615482 | 6652 | raw_spin_lock(&p->pi_lock); |
b29739f9 | 6653 | rq = __task_rq_lock(p); |
1da177e4 | 6654 | |
178be793 | 6655 | normalize_task(rq, p); |
3a5e4dc1 | 6656 | |
b29739f9 | 6657 | __task_rq_unlock(rq); |
1d615482 | 6658 | raw_spin_unlock(&p->pi_lock); |
a0f98a1c IM |
6659 | } while_each_thread(g, p); |
6660 | ||
4cf5d77a | 6661 | read_unlock_irqrestore(&tasklist_lock, flags); |
1da177e4 LT |
6662 | } |
6663 | ||
6664 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a | 6665 | |
67fc4e0c | 6666 | #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) |
1df5c10a | 6667 | /* |
67fc4e0c | 6668 | * These functions are only useful for the IA64 MCA handling, or kdb. |
1df5c10a LT |
6669 | * |
6670 | * They can only be called when the whole system has been | |
6671 | * stopped - every CPU needs to be quiescent, and no scheduling | |
6672 | * activity can take place. Using them for anything else would | |
6673 | * be a serious bug, and as a result, they aren't even visible | |
6674 | * under any other configuration. | |
6675 | */ | |
6676 | ||
6677 | /** | |
6678 | * curr_task - return the current task for a given cpu. | |
6679 | * @cpu: the processor in question. | |
6680 | * | |
6681 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
e69f6186 YB |
6682 | * |
6683 | * Return: The current task for @cpu. | |
1df5c10a | 6684 | */ |
36c8b586 | 6685 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
6686 | { |
6687 | return cpu_curr(cpu); | |
6688 | } | |
6689 | ||
67fc4e0c JW |
6690 | #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ |
6691 | ||
6692 | #ifdef CONFIG_IA64 | |
1df5c10a LT |
6693 | /** |
6694 | * set_curr_task - set the current task for a given cpu. | |
6695 | * @cpu: the processor in question. | |
6696 | * @p: the task pointer to set. | |
6697 | * | |
6698 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
6699 | * are serviced on a separate stack. It allows the architecture to switch the |
6700 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
6701 | * must be called with all CPU's synchronized, and interrupts disabled, the |
6702 | * and caller must save the original value of the current task (see | |
6703 | * curr_task() above) and restore that value before reenabling interrupts and | |
6704 | * re-starting the system. | |
6705 | * | |
6706 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
6707 | */ | |
36c8b586 | 6708 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
6709 | { |
6710 | cpu_curr(cpu) = p; | |
6711 | } | |
6712 | ||
6713 | #endif | |
29f59db3 | 6714 | |
7c941438 | 6715 | #ifdef CONFIG_CGROUP_SCHED |
029632fb PZ |
6716 | /* task_group_lock serializes the addition/removal of task groups */ |
6717 | static DEFINE_SPINLOCK(task_group_lock); | |
6718 | ||
bccbe08a PZ |
6719 | static void free_sched_group(struct task_group *tg) |
6720 | { | |
6721 | free_fair_sched_group(tg); | |
6722 | free_rt_sched_group(tg); | |
e9aa1dd1 | 6723 | autogroup_free(tg); |
bccbe08a PZ |
6724 | kfree(tg); |
6725 | } | |
6726 | ||
6727 | /* allocate runqueue etc for a new task group */ | |
ec7dc8ac | 6728 | struct task_group *sched_create_group(struct task_group *parent) |
bccbe08a PZ |
6729 | { |
6730 | struct task_group *tg; | |
bccbe08a PZ |
6731 | |
6732 | tg = kzalloc(sizeof(*tg), GFP_KERNEL); | |
6733 | if (!tg) | |
6734 | return ERR_PTR(-ENOMEM); | |
6735 | ||
ec7dc8ac | 6736 | if (!alloc_fair_sched_group(tg, parent)) |
bccbe08a PZ |
6737 | goto err; |
6738 | ||
ec7dc8ac | 6739 | if (!alloc_rt_sched_group(tg, parent)) |
bccbe08a PZ |
6740 | goto err; |
6741 | ||
ace783b9 LZ |
6742 | return tg; |
6743 | ||
6744 | err: | |
6745 | free_sched_group(tg); | |
6746 | return ERR_PTR(-ENOMEM); | |
6747 | } | |
6748 | ||
6749 | void sched_online_group(struct task_group *tg, struct task_group *parent) | |
6750 | { | |
6751 | unsigned long flags; | |
6752 | ||
8ed36996 | 6753 | spin_lock_irqsave(&task_group_lock, flags); |
6f505b16 | 6754 | list_add_rcu(&tg->list, &task_groups); |
f473aa5e PZ |
6755 | |
6756 | WARN_ON(!parent); /* root should already exist */ | |
6757 | ||
6758 | tg->parent = parent; | |
f473aa5e | 6759 | INIT_LIST_HEAD(&tg->children); |
09f2724a | 6760 | list_add_rcu(&tg->siblings, &parent->children); |
8ed36996 | 6761 | spin_unlock_irqrestore(&task_group_lock, flags); |
29f59db3 SV |
6762 | } |
6763 | ||
9b5b7751 | 6764 | /* rcu callback to free various structures associated with a task group */ |
6f505b16 | 6765 | static void free_sched_group_rcu(struct rcu_head *rhp) |
29f59db3 | 6766 | { |
29f59db3 | 6767 | /* now it should be safe to free those cfs_rqs */ |
6f505b16 | 6768 | free_sched_group(container_of(rhp, struct task_group, rcu)); |
29f59db3 SV |
6769 | } |
6770 | ||
9b5b7751 | 6771 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 6772 | void sched_destroy_group(struct task_group *tg) |
ace783b9 LZ |
6773 | { |
6774 | /* wait for possible concurrent references to cfs_rqs complete */ | |
6775 | call_rcu(&tg->rcu, free_sched_group_rcu); | |
6776 | } | |
6777 | ||
6778 | void sched_offline_group(struct task_group *tg) | |
29f59db3 | 6779 | { |
8ed36996 | 6780 | unsigned long flags; |
9b5b7751 | 6781 | int i; |
29f59db3 | 6782 | |
3d4b47b4 PZ |
6783 | /* end participation in shares distribution */ |
6784 | for_each_possible_cpu(i) | |
bccbe08a | 6785 | unregister_fair_sched_group(tg, i); |
3d4b47b4 PZ |
6786 | |
6787 | spin_lock_irqsave(&task_group_lock, flags); | |
6f505b16 | 6788 | list_del_rcu(&tg->list); |
f473aa5e | 6789 | list_del_rcu(&tg->siblings); |
8ed36996 | 6790 | spin_unlock_irqrestore(&task_group_lock, flags); |
29f59db3 SV |
6791 | } |
6792 | ||
9b5b7751 | 6793 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
6794 | * The caller of this function should have put the task in its new group |
6795 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
6796 | * reflect its new group. | |
9b5b7751 SV |
6797 | */ |
6798 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 | 6799 | { |
8323f26c | 6800 | struct task_group *tg; |
29f59db3 SV |
6801 | int on_rq, running; |
6802 | unsigned long flags; | |
6803 | struct rq *rq; | |
6804 | ||
6805 | rq = task_rq_lock(tsk, &flags); | |
6806 | ||
051a1d1a | 6807 | running = task_current(rq, tsk); |
fd2f4419 | 6808 | on_rq = tsk->on_rq; |
29f59db3 | 6809 | |
0e1f3483 | 6810 | if (on_rq) |
29f59db3 | 6811 | dequeue_task(rq, tsk, 0); |
0e1f3483 HS |
6812 | if (unlikely(running)) |
6813 | tsk->sched_class->put_prev_task(rq, tsk); | |
29f59db3 | 6814 | |
8af01f56 | 6815 | tg = container_of(task_css_check(tsk, cpu_cgroup_subsys_id, |
8323f26c PZ |
6816 | lockdep_is_held(&tsk->sighand->siglock)), |
6817 | struct task_group, css); | |
6818 | tg = autogroup_task_group(tsk, tg); | |
6819 | tsk->sched_task_group = tg; | |
6820 | ||
810b3817 | 6821 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 PZ |
6822 | if (tsk->sched_class->task_move_group) |
6823 | tsk->sched_class->task_move_group(tsk, on_rq); | |
6824 | else | |
810b3817 | 6825 | #endif |
b2b5ce02 | 6826 | set_task_rq(tsk, task_cpu(tsk)); |
810b3817 | 6827 | |
0e1f3483 HS |
6828 | if (unlikely(running)) |
6829 | tsk->sched_class->set_curr_task(rq); | |
6830 | if (on_rq) | |
371fd7e7 | 6831 | enqueue_task(rq, tsk, 0); |
29f59db3 | 6832 | |
0122ec5b | 6833 | task_rq_unlock(rq, tsk, &flags); |
29f59db3 | 6834 | } |
7c941438 | 6835 | #endif /* CONFIG_CGROUP_SCHED */ |
29f59db3 | 6836 | |
a790de99 | 6837 | #if defined(CONFIG_RT_GROUP_SCHED) || defined(CONFIG_CFS_BANDWIDTH) |
9f0c1e56 PZ |
6838 | static unsigned long to_ratio(u64 period, u64 runtime) |
6839 | { | |
6840 | if (runtime == RUNTIME_INF) | |
9a7e0b18 | 6841 | return 1ULL << 20; |
9f0c1e56 | 6842 | |
9a7e0b18 | 6843 | return div64_u64(runtime << 20, period); |
9f0c1e56 | 6844 | } |
a790de99 PT |
6845 | #endif |
6846 | ||
6847 | #ifdef CONFIG_RT_GROUP_SCHED | |
6848 | /* | |
6849 | * Ensure that the real time constraints are schedulable. | |
6850 | */ | |
6851 | static DEFINE_MUTEX(rt_constraints_mutex); | |
9f0c1e56 | 6852 | |
9a7e0b18 PZ |
6853 | /* Must be called with tasklist_lock held */ |
6854 | static inline int tg_has_rt_tasks(struct task_group *tg) | |
b40b2e8e | 6855 | { |
9a7e0b18 | 6856 | struct task_struct *g, *p; |
b40b2e8e | 6857 | |
9a7e0b18 | 6858 | do_each_thread(g, p) { |
029632fb | 6859 | if (rt_task(p) && task_rq(p)->rt.tg == tg) |
9a7e0b18 PZ |
6860 | return 1; |
6861 | } while_each_thread(g, p); | |
b40b2e8e | 6862 | |
9a7e0b18 PZ |
6863 | return 0; |
6864 | } | |
b40b2e8e | 6865 | |
9a7e0b18 PZ |
6866 | struct rt_schedulable_data { |
6867 | struct task_group *tg; | |
6868 | u64 rt_period; | |
6869 | u64 rt_runtime; | |
6870 | }; | |
b40b2e8e | 6871 | |
a790de99 | 6872 | static int tg_rt_schedulable(struct task_group *tg, void *data) |
9a7e0b18 PZ |
6873 | { |
6874 | struct rt_schedulable_data *d = data; | |
6875 | struct task_group *child; | |
6876 | unsigned long total, sum = 0; | |
6877 | u64 period, runtime; | |
b40b2e8e | 6878 | |
9a7e0b18 PZ |
6879 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
6880 | runtime = tg->rt_bandwidth.rt_runtime; | |
b40b2e8e | 6881 | |
9a7e0b18 PZ |
6882 | if (tg == d->tg) { |
6883 | period = d->rt_period; | |
6884 | runtime = d->rt_runtime; | |
b40b2e8e | 6885 | } |
b40b2e8e | 6886 | |
4653f803 PZ |
6887 | /* |
6888 | * Cannot have more runtime than the period. | |
6889 | */ | |
6890 | if (runtime > period && runtime != RUNTIME_INF) | |
6891 | return -EINVAL; | |
6f505b16 | 6892 | |
4653f803 PZ |
6893 | /* |
6894 | * Ensure we don't starve existing RT tasks. | |
6895 | */ | |
9a7e0b18 PZ |
6896 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
6897 | return -EBUSY; | |
6f505b16 | 6898 | |
9a7e0b18 | 6899 | total = to_ratio(period, runtime); |
6f505b16 | 6900 | |
4653f803 PZ |
6901 | /* |
6902 | * Nobody can have more than the global setting allows. | |
6903 | */ | |
6904 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) | |
6905 | return -EINVAL; | |
6f505b16 | 6906 | |
4653f803 PZ |
6907 | /* |
6908 | * The sum of our children's runtime should not exceed our own. | |
6909 | */ | |
9a7e0b18 PZ |
6910 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
6911 | period = ktime_to_ns(child->rt_bandwidth.rt_period); | |
6912 | runtime = child->rt_bandwidth.rt_runtime; | |
6f505b16 | 6913 | |
9a7e0b18 PZ |
6914 | if (child == d->tg) { |
6915 | period = d->rt_period; | |
6916 | runtime = d->rt_runtime; | |
6917 | } | |
6f505b16 | 6918 | |
9a7e0b18 | 6919 | sum += to_ratio(period, runtime); |
9f0c1e56 | 6920 | } |
6f505b16 | 6921 | |
9a7e0b18 PZ |
6922 | if (sum > total) |
6923 | return -EINVAL; | |
6924 | ||
6925 | return 0; | |
6f505b16 PZ |
6926 | } |
6927 | ||
9a7e0b18 | 6928 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
521f1a24 | 6929 | { |
8277434e PT |
6930 | int ret; |
6931 | ||
9a7e0b18 PZ |
6932 | struct rt_schedulable_data data = { |
6933 | .tg = tg, | |
6934 | .rt_period = period, | |
6935 | .rt_runtime = runtime, | |
6936 | }; | |
6937 | ||
8277434e PT |
6938 | rcu_read_lock(); |
6939 | ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); | |
6940 | rcu_read_unlock(); | |
6941 | ||
6942 | return ret; | |
521f1a24 DG |
6943 | } |
6944 | ||
ab84d31e | 6945 | static int tg_set_rt_bandwidth(struct task_group *tg, |
d0b27fa7 | 6946 | u64 rt_period, u64 rt_runtime) |
6f505b16 | 6947 | { |
ac086bc2 | 6948 | int i, err = 0; |
9f0c1e56 | 6949 | |
9f0c1e56 | 6950 | mutex_lock(&rt_constraints_mutex); |
521f1a24 | 6951 | read_lock(&tasklist_lock); |
9a7e0b18 PZ |
6952 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
6953 | if (err) | |
9f0c1e56 | 6954 | goto unlock; |
ac086bc2 | 6955 | |
0986b11b | 6956 | raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
d0b27fa7 PZ |
6957 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
6958 | tg->rt_bandwidth.rt_runtime = rt_runtime; | |
ac086bc2 PZ |
6959 | |
6960 | for_each_possible_cpu(i) { | |
6961 | struct rt_rq *rt_rq = tg->rt_rq[i]; | |
6962 | ||
0986b11b | 6963 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 6964 | rt_rq->rt_runtime = rt_runtime; |
0986b11b | 6965 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 6966 | } |
0986b11b | 6967 | raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
49246274 | 6968 | unlock: |
521f1a24 | 6969 | read_unlock(&tasklist_lock); |
9f0c1e56 PZ |
6970 | mutex_unlock(&rt_constraints_mutex); |
6971 | ||
6972 | return err; | |
6f505b16 PZ |
6973 | } |
6974 | ||
25cc7da7 | 6975 | static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
d0b27fa7 PZ |
6976 | { |
6977 | u64 rt_runtime, rt_period; | |
6978 | ||
6979 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
6980 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; | |
6981 | if (rt_runtime_us < 0) | |
6982 | rt_runtime = RUNTIME_INF; | |
6983 | ||
ab84d31e | 6984 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
6985 | } |
6986 | ||
25cc7da7 | 6987 | static long sched_group_rt_runtime(struct task_group *tg) |
9f0c1e56 PZ |
6988 | { |
6989 | u64 rt_runtime_us; | |
6990 | ||
d0b27fa7 | 6991 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
9f0c1e56 PZ |
6992 | return -1; |
6993 | ||
d0b27fa7 | 6994 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
9f0c1e56 PZ |
6995 | do_div(rt_runtime_us, NSEC_PER_USEC); |
6996 | return rt_runtime_us; | |
6997 | } | |
d0b27fa7 | 6998 | |
25cc7da7 | 6999 | static int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) |
d0b27fa7 PZ |
7000 | { |
7001 | u64 rt_runtime, rt_period; | |
7002 | ||
7003 | rt_period = (u64)rt_period_us * NSEC_PER_USEC; | |
7004 | rt_runtime = tg->rt_bandwidth.rt_runtime; | |
7005 | ||
619b0488 R |
7006 | if (rt_period == 0) |
7007 | return -EINVAL; | |
7008 | ||
ab84d31e | 7009 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
7010 | } |
7011 | ||
25cc7da7 | 7012 | static long sched_group_rt_period(struct task_group *tg) |
d0b27fa7 PZ |
7013 | { |
7014 | u64 rt_period_us; | |
7015 | ||
7016 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
7017 | do_div(rt_period_us, NSEC_PER_USEC); | |
7018 | return rt_period_us; | |
7019 | } | |
7020 | ||
7021 | static int sched_rt_global_constraints(void) | |
7022 | { | |
4653f803 | 7023 | u64 runtime, period; |
d0b27fa7 PZ |
7024 | int ret = 0; |
7025 | ||
ec5d4989 HS |
7026 | if (sysctl_sched_rt_period <= 0) |
7027 | return -EINVAL; | |
7028 | ||
4653f803 PZ |
7029 | runtime = global_rt_runtime(); |
7030 | period = global_rt_period(); | |
7031 | ||
7032 | /* | |
7033 | * Sanity check on the sysctl variables. | |
7034 | */ | |
7035 | if (runtime > period && runtime != RUNTIME_INF) | |
7036 | return -EINVAL; | |
10b612f4 | 7037 | |
d0b27fa7 | 7038 | mutex_lock(&rt_constraints_mutex); |
9a7e0b18 | 7039 | read_lock(&tasklist_lock); |
4653f803 | 7040 | ret = __rt_schedulable(NULL, 0, 0); |
9a7e0b18 | 7041 | read_unlock(&tasklist_lock); |
d0b27fa7 PZ |
7042 | mutex_unlock(&rt_constraints_mutex); |
7043 | ||
7044 | return ret; | |
7045 | } | |
54e99124 | 7046 | |
25cc7da7 | 7047 | static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
54e99124 DG |
7048 | { |
7049 | /* Don't accept realtime tasks when there is no way for them to run */ | |
7050 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) | |
7051 | return 0; | |
7052 | ||
7053 | return 1; | |
7054 | } | |
7055 | ||
6d6bc0ad | 7056 | #else /* !CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 PZ |
7057 | static int sched_rt_global_constraints(void) |
7058 | { | |
ac086bc2 PZ |
7059 | unsigned long flags; |
7060 | int i; | |
7061 | ||
ec5d4989 HS |
7062 | if (sysctl_sched_rt_period <= 0) |
7063 | return -EINVAL; | |
7064 | ||
60aa605d PZ |
7065 | /* |
7066 | * There's always some RT tasks in the root group | |
7067 | * -- migration, kstopmachine etc.. | |
7068 | */ | |
7069 | if (sysctl_sched_rt_runtime == 0) | |
7070 | return -EBUSY; | |
7071 | ||
0986b11b | 7072 | raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 PZ |
7073 | for_each_possible_cpu(i) { |
7074 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; | |
7075 | ||
0986b11b | 7076 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 7077 | rt_rq->rt_runtime = global_rt_runtime(); |
0986b11b | 7078 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 7079 | } |
0986b11b | 7080 | raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 | 7081 | |
d0b27fa7 PZ |
7082 | return 0; |
7083 | } | |
6d6bc0ad | 7084 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 7085 | |
ce0dbbbb CW |
7086 | int sched_rr_handler(struct ctl_table *table, int write, |
7087 | void __user *buffer, size_t *lenp, | |
7088 | loff_t *ppos) | |
7089 | { | |
7090 | int ret; | |
7091 | static DEFINE_MUTEX(mutex); | |
7092 | ||
7093 | mutex_lock(&mutex); | |
7094 | ret = proc_dointvec(table, write, buffer, lenp, ppos); | |
7095 | /* make sure that internally we keep jiffies */ | |
7096 | /* also, writing zero resets timeslice to default */ | |
7097 | if (!ret && write) { | |
7098 | sched_rr_timeslice = sched_rr_timeslice <= 0 ? | |
7099 | RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); | |
7100 | } | |
7101 | mutex_unlock(&mutex); | |
7102 | return ret; | |
7103 | } | |
7104 | ||
d0b27fa7 | 7105 | int sched_rt_handler(struct ctl_table *table, int write, |
8d65af78 | 7106 | void __user *buffer, size_t *lenp, |
d0b27fa7 PZ |
7107 | loff_t *ppos) |
7108 | { | |
7109 | int ret; | |
7110 | int old_period, old_runtime; | |
7111 | static DEFINE_MUTEX(mutex); | |
7112 | ||
7113 | mutex_lock(&mutex); | |
7114 | old_period = sysctl_sched_rt_period; | |
7115 | old_runtime = sysctl_sched_rt_runtime; | |
7116 | ||
8d65af78 | 7117 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
d0b27fa7 PZ |
7118 | |
7119 | if (!ret && write) { | |
7120 | ret = sched_rt_global_constraints(); | |
7121 | if (ret) { | |
7122 | sysctl_sched_rt_period = old_period; | |
7123 | sysctl_sched_rt_runtime = old_runtime; | |
7124 | } else { | |
7125 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); | |
7126 | def_rt_bandwidth.rt_period = | |
7127 | ns_to_ktime(global_rt_period()); | |
7128 | } | |
7129 | } | |
7130 | mutex_unlock(&mutex); | |
7131 | ||
7132 | return ret; | |
7133 | } | |
68318b8e | 7134 | |
052f1dc7 | 7135 | #ifdef CONFIG_CGROUP_SCHED |
68318b8e | 7136 | |
a7c6d554 | 7137 | static inline struct task_group *css_tg(struct cgroup_subsys_state *css) |
68318b8e | 7138 | { |
a7c6d554 | 7139 | return css ? container_of(css, struct task_group, css) : NULL; |
68318b8e SV |
7140 | } |
7141 | ||
eb95419b TH |
7142 | static struct cgroup_subsys_state * |
7143 | cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) | |
68318b8e | 7144 | { |
eb95419b TH |
7145 | struct task_group *parent = css_tg(parent_css); |
7146 | struct task_group *tg; | |
68318b8e | 7147 | |
eb95419b | 7148 | if (!parent) { |
68318b8e | 7149 | /* This is early initialization for the top cgroup */ |
07e06b01 | 7150 | return &root_task_group.css; |
68318b8e SV |
7151 | } |
7152 | ||
ec7dc8ac | 7153 | tg = sched_create_group(parent); |
68318b8e SV |
7154 | if (IS_ERR(tg)) |
7155 | return ERR_PTR(-ENOMEM); | |
7156 | ||
68318b8e SV |
7157 | return &tg->css; |
7158 | } | |
7159 | ||
eb95419b | 7160 | static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) |
ace783b9 | 7161 | { |
eb95419b TH |
7162 | struct task_group *tg = css_tg(css); |
7163 | struct task_group *parent = css_tg(css_parent(css)); | |
ace783b9 | 7164 | |
63876986 TH |
7165 | if (parent) |
7166 | sched_online_group(tg, parent); | |
ace783b9 LZ |
7167 | return 0; |
7168 | } | |
7169 | ||
eb95419b | 7170 | static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) |
68318b8e | 7171 | { |
eb95419b | 7172 | struct task_group *tg = css_tg(css); |
68318b8e SV |
7173 | |
7174 | sched_destroy_group(tg); | |
7175 | } | |
7176 | ||
eb95419b | 7177 | static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) |
ace783b9 | 7178 | { |
eb95419b | 7179 | struct task_group *tg = css_tg(css); |
ace783b9 LZ |
7180 | |
7181 | sched_offline_group(tg); | |
7182 | } | |
7183 | ||
eb95419b | 7184 | static int cpu_cgroup_can_attach(struct cgroup_subsys_state *css, |
bb9d97b6 | 7185 | struct cgroup_taskset *tset) |
68318b8e | 7186 | { |
bb9d97b6 TH |
7187 | struct task_struct *task; |
7188 | ||
d99c8727 | 7189 | cgroup_taskset_for_each(task, css, tset) { |
b68aa230 | 7190 | #ifdef CONFIG_RT_GROUP_SCHED |
eb95419b | 7191 | if (!sched_rt_can_attach(css_tg(css), task)) |
bb9d97b6 | 7192 | return -EINVAL; |
b68aa230 | 7193 | #else |
bb9d97b6 TH |
7194 | /* We don't support RT-tasks being in separate groups */ |
7195 | if (task->sched_class != &fair_sched_class) | |
7196 | return -EINVAL; | |
b68aa230 | 7197 | #endif |
bb9d97b6 | 7198 | } |
be367d09 BB |
7199 | return 0; |
7200 | } | |
68318b8e | 7201 | |
eb95419b | 7202 | static void cpu_cgroup_attach(struct cgroup_subsys_state *css, |
bb9d97b6 | 7203 | struct cgroup_taskset *tset) |
68318b8e | 7204 | { |
bb9d97b6 TH |
7205 | struct task_struct *task; |
7206 | ||
d99c8727 | 7207 | cgroup_taskset_for_each(task, css, tset) |
bb9d97b6 | 7208 | sched_move_task(task); |
68318b8e SV |
7209 | } |
7210 | ||
eb95419b TH |
7211 | static void cpu_cgroup_exit(struct cgroup_subsys_state *css, |
7212 | struct cgroup_subsys_state *old_css, | |
7213 | struct task_struct *task) | |
068c5cc5 PZ |
7214 | { |
7215 | /* | |
7216 | * cgroup_exit() is called in the copy_process() failure path. | |
7217 | * Ignore this case since the task hasn't ran yet, this avoids | |
7218 | * trying to poke a half freed task state from generic code. | |
7219 | */ | |
7220 | if (!(task->flags & PF_EXITING)) | |
7221 | return; | |
7222 | ||
7223 | sched_move_task(task); | |
7224 | } | |
7225 | ||
052f1dc7 | 7226 | #ifdef CONFIG_FAIR_GROUP_SCHED |
182446d0 TH |
7227 | static int cpu_shares_write_u64(struct cgroup_subsys_state *css, |
7228 | struct cftype *cftype, u64 shareval) | |
68318b8e | 7229 | { |
182446d0 | 7230 | return sched_group_set_shares(css_tg(css), scale_load(shareval)); |
68318b8e SV |
7231 | } |
7232 | ||
182446d0 TH |
7233 | static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, |
7234 | struct cftype *cft) | |
68318b8e | 7235 | { |
182446d0 | 7236 | struct task_group *tg = css_tg(css); |
68318b8e | 7237 | |
c8b28116 | 7238 | return (u64) scale_load_down(tg->shares); |
68318b8e | 7239 | } |
ab84d31e PT |
7240 | |
7241 | #ifdef CONFIG_CFS_BANDWIDTH | |
a790de99 PT |
7242 | static DEFINE_MUTEX(cfs_constraints_mutex); |
7243 | ||
ab84d31e PT |
7244 | const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ |
7245 | const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ | |
7246 | ||
a790de99 PT |
7247 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); |
7248 | ||
ab84d31e PT |
7249 | static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) |
7250 | { | |
56f570e5 | 7251 | int i, ret = 0, runtime_enabled, runtime_was_enabled; |
029632fb | 7252 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
ab84d31e PT |
7253 | |
7254 | if (tg == &root_task_group) | |
7255 | return -EINVAL; | |
7256 | ||
7257 | /* | |
7258 | * Ensure we have at some amount of bandwidth every period. This is | |
7259 | * to prevent reaching a state of large arrears when throttled via | |
7260 | * entity_tick() resulting in prolonged exit starvation. | |
7261 | */ | |
7262 | if (quota < min_cfs_quota_period || period < min_cfs_quota_period) | |
7263 | return -EINVAL; | |
7264 | ||
7265 | /* | |
7266 | * Likewise, bound things on the otherside by preventing insane quota | |
7267 | * periods. This also allows us to normalize in computing quota | |
7268 | * feasibility. | |
7269 | */ | |
7270 | if (period > max_cfs_quota_period) | |
7271 | return -EINVAL; | |
7272 | ||
a790de99 PT |
7273 | mutex_lock(&cfs_constraints_mutex); |
7274 | ret = __cfs_schedulable(tg, period, quota); | |
7275 | if (ret) | |
7276 | goto out_unlock; | |
7277 | ||
58088ad0 | 7278 | runtime_enabled = quota != RUNTIME_INF; |
56f570e5 PT |
7279 | runtime_was_enabled = cfs_b->quota != RUNTIME_INF; |
7280 | account_cfs_bandwidth_used(runtime_enabled, runtime_was_enabled); | |
ab84d31e PT |
7281 | raw_spin_lock_irq(&cfs_b->lock); |
7282 | cfs_b->period = ns_to_ktime(period); | |
7283 | cfs_b->quota = quota; | |
58088ad0 | 7284 | |
a9cf55b2 | 7285 | __refill_cfs_bandwidth_runtime(cfs_b); |
58088ad0 PT |
7286 | /* restart the period timer (if active) to handle new period expiry */ |
7287 | if (runtime_enabled && cfs_b->timer_active) { | |
7288 | /* force a reprogram */ | |
7289 | cfs_b->timer_active = 0; | |
7290 | __start_cfs_bandwidth(cfs_b); | |
7291 | } | |
ab84d31e PT |
7292 | raw_spin_unlock_irq(&cfs_b->lock); |
7293 | ||
7294 | for_each_possible_cpu(i) { | |
7295 | struct cfs_rq *cfs_rq = tg->cfs_rq[i]; | |
029632fb | 7296 | struct rq *rq = cfs_rq->rq; |
ab84d31e PT |
7297 | |
7298 | raw_spin_lock_irq(&rq->lock); | |
58088ad0 | 7299 | cfs_rq->runtime_enabled = runtime_enabled; |
ab84d31e | 7300 | cfs_rq->runtime_remaining = 0; |
671fd9da | 7301 | |
029632fb | 7302 | if (cfs_rq->throttled) |
671fd9da | 7303 | unthrottle_cfs_rq(cfs_rq); |
ab84d31e PT |
7304 | raw_spin_unlock_irq(&rq->lock); |
7305 | } | |
a790de99 PT |
7306 | out_unlock: |
7307 | mutex_unlock(&cfs_constraints_mutex); | |
ab84d31e | 7308 | |
a790de99 | 7309 | return ret; |
ab84d31e PT |
7310 | } |
7311 | ||
7312 | int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) | |
7313 | { | |
7314 | u64 quota, period; | |
7315 | ||
029632fb | 7316 | period = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
7317 | if (cfs_quota_us < 0) |
7318 | quota = RUNTIME_INF; | |
7319 | else | |
7320 | quota = (u64)cfs_quota_us * NSEC_PER_USEC; | |
7321 | ||
7322 | return tg_set_cfs_bandwidth(tg, period, quota); | |
7323 | } | |
7324 | ||
7325 | long tg_get_cfs_quota(struct task_group *tg) | |
7326 | { | |
7327 | u64 quota_us; | |
7328 | ||
029632fb | 7329 | if (tg->cfs_bandwidth.quota == RUNTIME_INF) |
ab84d31e PT |
7330 | return -1; |
7331 | ||
029632fb | 7332 | quota_us = tg->cfs_bandwidth.quota; |
ab84d31e PT |
7333 | do_div(quota_us, NSEC_PER_USEC); |
7334 | ||
7335 | return quota_us; | |
7336 | } | |
7337 | ||
7338 | int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) | |
7339 | { | |
7340 | u64 quota, period; | |
7341 | ||
7342 | period = (u64)cfs_period_us * NSEC_PER_USEC; | |
029632fb | 7343 | quota = tg->cfs_bandwidth.quota; |
ab84d31e | 7344 | |
ab84d31e PT |
7345 | return tg_set_cfs_bandwidth(tg, period, quota); |
7346 | } | |
7347 | ||
7348 | long tg_get_cfs_period(struct task_group *tg) | |
7349 | { | |
7350 | u64 cfs_period_us; | |
7351 | ||
029632fb | 7352 | cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
7353 | do_div(cfs_period_us, NSEC_PER_USEC); |
7354 | ||
7355 | return cfs_period_us; | |
7356 | } | |
7357 | ||
182446d0 TH |
7358 | static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, |
7359 | struct cftype *cft) | |
ab84d31e | 7360 | { |
182446d0 | 7361 | return tg_get_cfs_quota(css_tg(css)); |
ab84d31e PT |
7362 | } |
7363 | ||
182446d0 TH |
7364 | static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, |
7365 | struct cftype *cftype, s64 cfs_quota_us) | |
ab84d31e | 7366 | { |
182446d0 | 7367 | return tg_set_cfs_quota(css_tg(css), cfs_quota_us); |
ab84d31e PT |
7368 | } |
7369 | ||
182446d0 TH |
7370 | static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, |
7371 | struct cftype *cft) | |
ab84d31e | 7372 | { |
182446d0 | 7373 | return tg_get_cfs_period(css_tg(css)); |
ab84d31e PT |
7374 | } |
7375 | ||
182446d0 TH |
7376 | static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, |
7377 | struct cftype *cftype, u64 cfs_period_us) | |
ab84d31e | 7378 | { |
182446d0 | 7379 | return tg_set_cfs_period(css_tg(css), cfs_period_us); |
ab84d31e PT |
7380 | } |
7381 | ||
a790de99 PT |
7382 | struct cfs_schedulable_data { |
7383 | struct task_group *tg; | |
7384 | u64 period, quota; | |
7385 | }; | |
7386 | ||
7387 | /* | |
7388 | * normalize group quota/period to be quota/max_period | |
7389 | * note: units are usecs | |
7390 | */ | |
7391 | static u64 normalize_cfs_quota(struct task_group *tg, | |
7392 | struct cfs_schedulable_data *d) | |
7393 | { | |
7394 | u64 quota, period; | |
7395 | ||
7396 | if (tg == d->tg) { | |
7397 | period = d->period; | |
7398 | quota = d->quota; | |
7399 | } else { | |
7400 | period = tg_get_cfs_period(tg); | |
7401 | quota = tg_get_cfs_quota(tg); | |
7402 | } | |
7403 | ||
7404 | /* note: these should typically be equivalent */ | |
7405 | if (quota == RUNTIME_INF || quota == -1) | |
7406 | return RUNTIME_INF; | |
7407 | ||
7408 | return to_ratio(period, quota); | |
7409 | } | |
7410 | ||
7411 | static int tg_cfs_schedulable_down(struct task_group *tg, void *data) | |
7412 | { | |
7413 | struct cfs_schedulable_data *d = data; | |
029632fb | 7414 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
a790de99 PT |
7415 | s64 quota = 0, parent_quota = -1; |
7416 | ||
7417 | if (!tg->parent) { | |
7418 | quota = RUNTIME_INF; | |
7419 | } else { | |
029632fb | 7420 | struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; |
a790de99 PT |
7421 | |
7422 | quota = normalize_cfs_quota(tg, d); | |
7423 | parent_quota = parent_b->hierarchal_quota; | |
7424 | ||
7425 | /* | |
7426 | * ensure max(child_quota) <= parent_quota, inherit when no | |
7427 | * limit is set | |
7428 | */ | |
7429 | if (quota == RUNTIME_INF) | |
7430 | quota = parent_quota; | |
7431 | else if (parent_quota != RUNTIME_INF && quota > parent_quota) | |
7432 | return -EINVAL; | |
7433 | } | |
7434 | cfs_b->hierarchal_quota = quota; | |
7435 | ||
7436 | return 0; | |
7437 | } | |
7438 | ||
7439 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) | |
7440 | { | |
8277434e | 7441 | int ret; |
a790de99 PT |
7442 | struct cfs_schedulable_data data = { |
7443 | .tg = tg, | |
7444 | .period = period, | |
7445 | .quota = quota, | |
7446 | }; | |
7447 | ||
7448 | if (quota != RUNTIME_INF) { | |
7449 | do_div(data.period, NSEC_PER_USEC); | |
7450 | do_div(data.quota, NSEC_PER_USEC); | |
7451 | } | |
7452 | ||
8277434e PT |
7453 | rcu_read_lock(); |
7454 | ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); | |
7455 | rcu_read_unlock(); | |
7456 | ||
7457 | return ret; | |
a790de99 | 7458 | } |
e8da1b18 | 7459 | |
182446d0 | 7460 | static int cpu_stats_show(struct cgroup_subsys_state *css, struct cftype *cft, |
e8da1b18 NR |
7461 | struct cgroup_map_cb *cb) |
7462 | { | |
182446d0 | 7463 | struct task_group *tg = css_tg(css); |
029632fb | 7464 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
e8da1b18 NR |
7465 | |
7466 | cb->fill(cb, "nr_periods", cfs_b->nr_periods); | |
7467 | cb->fill(cb, "nr_throttled", cfs_b->nr_throttled); | |
7468 | cb->fill(cb, "throttled_time", cfs_b->throttled_time); | |
7469 | ||
7470 | return 0; | |
7471 | } | |
ab84d31e | 7472 | #endif /* CONFIG_CFS_BANDWIDTH */ |
6d6bc0ad | 7473 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e | 7474 | |
052f1dc7 | 7475 | #ifdef CONFIG_RT_GROUP_SCHED |
182446d0 TH |
7476 | static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, |
7477 | struct cftype *cft, s64 val) | |
6f505b16 | 7478 | { |
182446d0 | 7479 | return sched_group_set_rt_runtime(css_tg(css), val); |
6f505b16 PZ |
7480 | } |
7481 | ||
182446d0 TH |
7482 | static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, |
7483 | struct cftype *cft) | |
6f505b16 | 7484 | { |
182446d0 | 7485 | return sched_group_rt_runtime(css_tg(css)); |
6f505b16 | 7486 | } |
d0b27fa7 | 7487 | |
182446d0 TH |
7488 | static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, |
7489 | struct cftype *cftype, u64 rt_period_us) | |
d0b27fa7 | 7490 | { |
182446d0 | 7491 | return sched_group_set_rt_period(css_tg(css), rt_period_us); |
d0b27fa7 PZ |
7492 | } |
7493 | ||
182446d0 TH |
7494 | static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, |
7495 | struct cftype *cft) | |
d0b27fa7 | 7496 | { |
182446d0 | 7497 | return sched_group_rt_period(css_tg(css)); |
d0b27fa7 | 7498 | } |
6d6bc0ad | 7499 | #endif /* CONFIG_RT_GROUP_SCHED */ |
6f505b16 | 7500 | |
fe5c7cc2 | 7501 | static struct cftype cpu_files[] = { |
052f1dc7 | 7502 | #ifdef CONFIG_FAIR_GROUP_SCHED |
fe5c7cc2 PM |
7503 | { |
7504 | .name = "shares", | |
f4c753b7 PM |
7505 | .read_u64 = cpu_shares_read_u64, |
7506 | .write_u64 = cpu_shares_write_u64, | |
fe5c7cc2 | 7507 | }, |
052f1dc7 | 7508 | #endif |
ab84d31e PT |
7509 | #ifdef CONFIG_CFS_BANDWIDTH |
7510 | { | |
7511 | .name = "cfs_quota_us", | |
7512 | .read_s64 = cpu_cfs_quota_read_s64, | |
7513 | .write_s64 = cpu_cfs_quota_write_s64, | |
7514 | }, | |
7515 | { | |
7516 | .name = "cfs_period_us", | |
7517 | .read_u64 = cpu_cfs_period_read_u64, | |
7518 | .write_u64 = cpu_cfs_period_write_u64, | |
7519 | }, | |
e8da1b18 NR |
7520 | { |
7521 | .name = "stat", | |
7522 | .read_map = cpu_stats_show, | |
7523 | }, | |
ab84d31e | 7524 | #endif |
052f1dc7 | 7525 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 7526 | { |
9f0c1e56 | 7527 | .name = "rt_runtime_us", |
06ecb27c PM |
7528 | .read_s64 = cpu_rt_runtime_read, |
7529 | .write_s64 = cpu_rt_runtime_write, | |
6f505b16 | 7530 | }, |
d0b27fa7 PZ |
7531 | { |
7532 | .name = "rt_period_us", | |
f4c753b7 PM |
7533 | .read_u64 = cpu_rt_period_read_uint, |
7534 | .write_u64 = cpu_rt_period_write_uint, | |
d0b27fa7 | 7535 | }, |
052f1dc7 | 7536 | #endif |
4baf6e33 | 7537 | { } /* terminate */ |
68318b8e SV |
7538 | }; |
7539 | ||
68318b8e | 7540 | struct cgroup_subsys cpu_cgroup_subsys = { |
38605cae | 7541 | .name = "cpu", |
92fb9748 TH |
7542 | .css_alloc = cpu_cgroup_css_alloc, |
7543 | .css_free = cpu_cgroup_css_free, | |
ace783b9 LZ |
7544 | .css_online = cpu_cgroup_css_online, |
7545 | .css_offline = cpu_cgroup_css_offline, | |
bb9d97b6 TH |
7546 | .can_attach = cpu_cgroup_can_attach, |
7547 | .attach = cpu_cgroup_attach, | |
068c5cc5 | 7548 | .exit = cpu_cgroup_exit, |
38605cae | 7549 | .subsys_id = cpu_cgroup_subsys_id, |
4baf6e33 | 7550 | .base_cftypes = cpu_files, |
68318b8e SV |
7551 | .early_init = 1, |
7552 | }; | |
7553 | ||
052f1dc7 | 7554 | #endif /* CONFIG_CGROUP_SCHED */ |
d842de87 | 7555 | |
b637a328 PM |
7556 | void dump_cpu_task(int cpu) |
7557 | { | |
7558 | pr_info("Task dump for CPU %d:\n", cpu); | |
7559 | sched_show_task(cpu_curr(cpu)); | |
7560 | } |