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 | ||
e1b77c92 | 29 | #include <linux/kasan.h> |
1da177e4 LT |
30 | #include <linux/mm.h> |
31 | #include <linux/module.h> | |
32 | #include <linux/nmi.h> | |
33 | #include <linux/init.h> | |
dff06c15 | 34 | #include <linux/uaccess.h> |
1da177e4 | 35 | #include <linux/highmem.h> |
f98db601 | 36 | #include <linux/mmu_context.h> |
1da177e4 | 37 | #include <linux/interrupt.h> |
c59ede7b | 38 | #include <linux/capability.h> |
1da177e4 LT |
39 | #include <linux/completion.h> |
40 | #include <linux/kernel_stat.h> | |
9a11b49a | 41 | #include <linux/debug_locks.h> |
cdd6c482 | 42 | #include <linux/perf_event.h> |
1da177e4 LT |
43 | #include <linux/security.h> |
44 | #include <linux/notifier.h> | |
45 | #include <linux/profile.h> | |
7dfb7103 | 46 | #include <linux/freezer.h> |
198e2f18 | 47 | #include <linux/vmalloc.h> |
1da177e4 LT |
48 | #include <linux/blkdev.h> |
49 | #include <linux/delay.h> | |
b488893a | 50 | #include <linux/pid_namespace.h> |
1da177e4 LT |
51 | #include <linux/smp.h> |
52 | #include <linux/threads.h> | |
53 | #include <linux/timer.h> | |
54 | #include <linux/rcupdate.h> | |
55 | #include <linux/cpu.h> | |
56 | #include <linux/cpuset.h> | |
57 | #include <linux/percpu.h> | |
b5aadf7f | 58 | #include <linux/proc_fs.h> |
1da177e4 | 59 | #include <linux/seq_file.h> |
e692ab53 | 60 | #include <linux/sysctl.h> |
1da177e4 LT |
61 | #include <linux/syscalls.h> |
62 | #include <linux/times.h> | |
8f0ab514 | 63 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 64 | #include <linux/kprobes.h> |
0ff92245 | 65 | #include <linux/delayacct.h> |
dff06c15 | 66 | #include <linux/unistd.h> |
f5ff8422 | 67 | #include <linux/pagemap.h> |
8f4d37ec | 68 | #include <linux/hrtimer.h> |
30914a58 | 69 | #include <linux/tick.h> |
f00b45c1 | 70 | #include <linux/ctype.h> |
6cd8a4bb | 71 | #include <linux/ftrace.h> |
5a0e3ad6 | 72 | #include <linux/slab.h> |
f1c6f1a7 | 73 | #include <linux/init_task.h> |
91d1aa43 | 74 | #include <linux/context_tracking.h> |
52f5684c | 75 | #include <linux/compiler.h> |
8e05e96a | 76 | #include <linux/frame.h> |
6075620b | 77 | #include <linux/prefetch.h> |
1da177e4 | 78 | |
96f951ed | 79 | #include <asm/switch_to.h> |
5517d86b | 80 | #include <asm/tlb.h> |
838225b4 | 81 | #include <asm/irq_regs.h> |
db7e527d | 82 | #include <asm/mutex.h> |
e6e6685a GC |
83 | #ifdef CONFIG_PARAVIRT |
84 | #include <asm/paravirt.h> | |
85 | #endif | |
1da177e4 | 86 | |
029632fb | 87 | #include "sched.h" |
ea138446 | 88 | #include "../workqueue_internal.h" |
29d5e047 | 89 | #include "../smpboot.h" |
6e0534f2 | 90 | |
a8d154b0 | 91 | #define CREATE_TRACE_POINTS |
ad8d75ff | 92 | #include <trace/events/sched.h> |
a8d154b0 | 93 | |
029632fb PZ |
94 | DEFINE_MUTEX(sched_domains_mutex); |
95 | DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); | |
dc61b1d6 | 96 | |
fe44d621 | 97 | static void update_rq_clock_task(struct rq *rq, s64 delta); |
305e6835 | 98 | |
029632fb | 99 | void update_rq_clock(struct rq *rq) |
3e51f33f | 100 | { |
fe44d621 | 101 | s64 delta; |
305e6835 | 102 | |
9edfbfed PZ |
103 | lockdep_assert_held(&rq->lock); |
104 | ||
105 | if (rq->clock_skip_update & RQCF_ACT_SKIP) | |
f26f9aff | 106 | return; |
aa483808 | 107 | |
fe44d621 | 108 | delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; |
4036ac15 MG |
109 | if (delta < 0) |
110 | return; | |
fe44d621 PZ |
111 | rq->clock += delta; |
112 | update_rq_clock_task(rq, delta); | |
3e51f33f PZ |
113 | } |
114 | ||
bf5c91ba IM |
115 | /* |
116 | * Debugging: various feature bits | |
117 | */ | |
f00b45c1 | 118 | |
f00b45c1 PZ |
119 | #define SCHED_FEAT(name, enabled) \ |
120 | (1UL << __SCHED_FEAT_##name) * enabled | | |
121 | ||
bf5c91ba | 122 | const_debug unsigned int sysctl_sched_features = |
391e43da | 123 | #include "features.h" |
f00b45c1 PZ |
124 | 0; |
125 | ||
126 | #undef SCHED_FEAT | |
127 | ||
b82d9fdd PZ |
128 | /* |
129 | * Number of tasks to iterate in a single balance run. | |
130 | * Limited because this is done with IRQs disabled. | |
131 | */ | |
132 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
133 | ||
e9e9250b PZ |
134 | /* |
135 | * period over which we average the RT time consumption, measured | |
136 | * in ms. | |
137 | * | |
138 | * default: 1s | |
139 | */ | |
140 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; | |
141 | ||
fa85ae24 | 142 | /* |
9f0c1e56 | 143 | * period over which we measure -rt task cpu usage in us. |
fa85ae24 PZ |
144 | * default: 1s |
145 | */ | |
9f0c1e56 | 146 | unsigned int sysctl_sched_rt_period = 1000000; |
fa85ae24 | 147 | |
029632fb | 148 | __read_mostly int scheduler_running; |
6892b75e | 149 | |
9f0c1e56 PZ |
150 | /* |
151 | * part of the period that we allow rt tasks to run in us. | |
152 | * default: 0.95s | |
153 | */ | |
154 | int sysctl_sched_rt_runtime = 950000; | |
fa85ae24 | 155 | |
3fa0818b RR |
156 | /* cpus with isolated domains */ |
157 | cpumask_var_t cpu_isolated_map; | |
158 | ||
1da177e4 | 159 | /* |
cc2a73b5 | 160 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 161 | */ |
a9957449 | 162 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
163 | __acquires(rq->lock) |
164 | { | |
70b97a7f | 165 | struct rq *rq; |
1da177e4 LT |
166 | |
167 | local_irq_disable(); | |
168 | rq = this_rq(); | |
05fa785c | 169 | raw_spin_lock(&rq->lock); |
1da177e4 LT |
170 | |
171 | return rq; | |
172 | } | |
173 | ||
3e71a462 PZ |
174 | /* |
175 | * __task_rq_lock - lock the rq @p resides on. | |
176 | */ | |
eb580751 | 177 | struct rq *__task_rq_lock(struct task_struct *p, struct rq_flags *rf) |
3e71a462 PZ |
178 | __acquires(rq->lock) |
179 | { | |
180 | struct rq *rq; | |
181 | ||
182 | lockdep_assert_held(&p->pi_lock); | |
183 | ||
184 | for (;;) { | |
185 | rq = task_rq(p); | |
186 | raw_spin_lock(&rq->lock); | |
187 | if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) { | |
e7904a28 | 188 | rf->cookie = lockdep_pin_lock(&rq->lock); |
3e71a462 PZ |
189 | return rq; |
190 | } | |
191 | raw_spin_unlock(&rq->lock); | |
192 | ||
193 | while (unlikely(task_on_rq_migrating(p))) | |
194 | cpu_relax(); | |
195 | } | |
196 | } | |
197 | ||
198 | /* | |
199 | * task_rq_lock - lock p->pi_lock and lock the rq @p resides on. | |
200 | */ | |
eb580751 | 201 | struct rq *task_rq_lock(struct task_struct *p, struct rq_flags *rf) |
3e71a462 PZ |
202 | __acquires(p->pi_lock) |
203 | __acquires(rq->lock) | |
204 | { | |
205 | struct rq *rq; | |
206 | ||
207 | for (;;) { | |
eb580751 | 208 | raw_spin_lock_irqsave(&p->pi_lock, rf->flags); |
3e71a462 PZ |
209 | rq = task_rq(p); |
210 | raw_spin_lock(&rq->lock); | |
211 | /* | |
212 | * move_queued_task() task_rq_lock() | |
213 | * | |
214 | * ACQUIRE (rq->lock) | |
215 | * [S] ->on_rq = MIGRATING [L] rq = task_rq() | |
216 | * WMB (__set_task_cpu()) ACQUIRE (rq->lock); | |
217 | * [S] ->cpu = new_cpu [L] task_rq() | |
218 | * [L] ->on_rq | |
219 | * RELEASE (rq->lock) | |
220 | * | |
221 | * If we observe the old cpu in task_rq_lock, the acquire of | |
222 | * the old rq->lock will fully serialize against the stores. | |
223 | * | |
224 | * If we observe the new cpu in task_rq_lock, the acquire will | |
225 | * pair with the WMB to ensure we must then also see migrating. | |
226 | */ | |
227 | if (likely(rq == task_rq(p) && !task_on_rq_migrating(p))) { | |
e7904a28 | 228 | rf->cookie = lockdep_pin_lock(&rq->lock); |
3e71a462 PZ |
229 | return rq; |
230 | } | |
231 | raw_spin_unlock(&rq->lock); | |
eb580751 | 232 | raw_spin_unlock_irqrestore(&p->pi_lock, rf->flags); |
3e71a462 PZ |
233 | |
234 | while (unlikely(task_on_rq_migrating(p))) | |
235 | cpu_relax(); | |
236 | } | |
237 | } | |
238 | ||
8f4d37ec PZ |
239 | #ifdef CONFIG_SCHED_HRTICK |
240 | /* | |
241 | * Use HR-timers to deliver accurate preemption points. | |
8f4d37ec | 242 | */ |
8f4d37ec | 243 | |
8f4d37ec PZ |
244 | static void hrtick_clear(struct rq *rq) |
245 | { | |
246 | if (hrtimer_active(&rq->hrtick_timer)) | |
247 | hrtimer_cancel(&rq->hrtick_timer); | |
248 | } | |
249 | ||
8f4d37ec PZ |
250 | /* |
251 | * High-resolution timer tick. | |
252 | * Runs from hardirq context with interrupts disabled. | |
253 | */ | |
254 | static enum hrtimer_restart hrtick(struct hrtimer *timer) | |
255 | { | |
256 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); | |
257 | ||
258 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
259 | ||
05fa785c | 260 | raw_spin_lock(&rq->lock); |
3e51f33f | 261 | update_rq_clock(rq); |
8f4d37ec | 262 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
05fa785c | 263 | raw_spin_unlock(&rq->lock); |
8f4d37ec PZ |
264 | |
265 | return HRTIMER_NORESTART; | |
266 | } | |
267 | ||
95e904c7 | 268 | #ifdef CONFIG_SMP |
971ee28c | 269 | |
4961b6e1 | 270 | static void __hrtick_restart(struct rq *rq) |
971ee28c PZ |
271 | { |
272 | struct hrtimer *timer = &rq->hrtick_timer; | |
971ee28c | 273 | |
4961b6e1 | 274 | hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); |
971ee28c PZ |
275 | } |
276 | ||
31656519 PZ |
277 | /* |
278 | * called from hardirq (IPI) context | |
279 | */ | |
280 | static void __hrtick_start(void *arg) | |
b328ca18 | 281 | { |
31656519 | 282 | struct rq *rq = arg; |
b328ca18 | 283 | |
05fa785c | 284 | raw_spin_lock(&rq->lock); |
971ee28c | 285 | __hrtick_restart(rq); |
31656519 | 286 | rq->hrtick_csd_pending = 0; |
05fa785c | 287 | raw_spin_unlock(&rq->lock); |
b328ca18 PZ |
288 | } |
289 | ||
31656519 PZ |
290 | /* |
291 | * Called to set the hrtick timer state. | |
292 | * | |
293 | * called with rq->lock held and irqs disabled | |
294 | */ | |
029632fb | 295 | void hrtick_start(struct rq *rq, u64 delay) |
b328ca18 | 296 | { |
31656519 | 297 | struct hrtimer *timer = &rq->hrtick_timer; |
177ef2a6 | 298 | ktime_t time; |
299 | s64 delta; | |
300 | ||
301 | /* | |
302 | * Don't schedule slices shorter than 10000ns, that just | |
303 | * doesn't make sense and can cause timer DoS. | |
304 | */ | |
305 | delta = max_t(s64, delay, 10000LL); | |
306 | time = ktime_add_ns(timer->base->get_time(), delta); | |
b328ca18 | 307 | |
cc584b21 | 308 | hrtimer_set_expires(timer, time); |
31656519 PZ |
309 | |
310 | if (rq == this_rq()) { | |
971ee28c | 311 | __hrtick_restart(rq); |
31656519 | 312 | } else if (!rq->hrtick_csd_pending) { |
c46fff2a | 313 | smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); |
31656519 PZ |
314 | rq->hrtick_csd_pending = 1; |
315 | } | |
b328ca18 PZ |
316 | } |
317 | ||
31656519 PZ |
318 | #else |
319 | /* | |
320 | * Called to set the hrtick timer state. | |
321 | * | |
322 | * called with rq->lock held and irqs disabled | |
323 | */ | |
029632fb | 324 | void hrtick_start(struct rq *rq, u64 delay) |
31656519 | 325 | { |
86893335 WL |
326 | /* |
327 | * Don't schedule slices shorter than 10000ns, that just | |
328 | * doesn't make sense. Rely on vruntime for fairness. | |
329 | */ | |
330 | delay = max_t(u64, delay, 10000LL); | |
4961b6e1 TG |
331 | hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), |
332 | HRTIMER_MODE_REL_PINNED); | |
31656519 | 333 | } |
31656519 | 334 | #endif /* CONFIG_SMP */ |
8f4d37ec | 335 | |
31656519 | 336 | static void init_rq_hrtick(struct rq *rq) |
8f4d37ec | 337 | { |
31656519 PZ |
338 | #ifdef CONFIG_SMP |
339 | rq->hrtick_csd_pending = 0; | |
8f4d37ec | 340 | |
31656519 PZ |
341 | rq->hrtick_csd.flags = 0; |
342 | rq->hrtick_csd.func = __hrtick_start; | |
343 | rq->hrtick_csd.info = rq; | |
344 | #endif | |
8f4d37ec | 345 | |
31656519 PZ |
346 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
347 | rq->hrtick_timer.function = hrtick; | |
8f4d37ec | 348 | } |
006c75f1 | 349 | #else /* CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
350 | static inline void hrtick_clear(struct rq *rq) |
351 | { | |
352 | } | |
353 | ||
8f4d37ec PZ |
354 | static inline void init_rq_hrtick(struct rq *rq) |
355 | { | |
356 | } | |
006c75f1 | 357 | #endif /* CONFIG_SCHED_HRTICK */ |
8f4d37ec | 358 | |
5529578a FW |
359 | /* |
360 | * cmpxchg based fetch_or, macro so it works for different integer types | |
361 | */ | |
362 | #define fetch_or(ptr, mask) \ | |
363 | ({ \ | |
364 | typeof(ptr) _ptr = (ptr); \ | |
365 | typeof(mask) _mask = (mask); \ | |
366 | typeof(*_ptr) _old, _val = *_ptr; \ | |
367 | \ | |
368 | for (;;) { \ | |
369 | _old = cmpxchg(_ptr, _val, _val | _mask); \ | |
370 | if (_old == _val) \ | |
371 | break; \ | |
372 | _val = _old; \ | |
373 | } \ | |
374 | _old; \ | |
375 | }) | |
376 | ||
e3baac47 | 377 | #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) |
fd99f91a PZ |
378 | /* |
379 | * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, | |
380 | * this avoids any races wrt polling state changes and thereby avoids | |
381 | * spurious IPIs. | |
382 | */ | |
383 | static bool set_nr_and_not_polling(struct task_struct *p) | |
384 | { | |
385 | struct thread_info *ti = task_thread_info(p); | |
386 | return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); | |
387 | } | |
e3baac47 PZ |
388 | |
389 | /* | |
390 | * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. | |
391 | * | |
392 | * If this returns true, then the idle task promises to call | |
393 | * sched_ttwu_pending() and reschedule soon. | |
394 | */ | |
395 | static bool set_nr_if_polling(struct task_struct *p) | |
396 | { | |
397 | struct thread_info *ti = task_thread_info(p); | |
316c1608 | 398 | typeof(ti->flags) old, val = READ_ONCE(ti->flags); |
e3baac47 PZ |
399 | |
400 | for (;;) { | |
401 | if (!(val & _TIF_POLLING_NRFLAG)) | |
402 | return false; | |
403 | if (val & _TIF_NEED_RESCHED) | |
404 | return true; | |
405 | old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); | |
406 | if (old == val) | |
407 | break; | |
408 | val = old; | |
409 | } | |
410 | return true; | |
411 | } | |
412 | ||
fd99f91a PZ |
413 | #else |
414 | static bool set_nr_and_not_polling(struct task_struct *p) | |
415 | { | |
416 | set_tsk_need_resched(p); | |
417 | return true; | |
418 | } | |
e3baac47 PZ |
419 | |
420 | #ifdef CONFIG_SMP | |
421 | static bool set_nr_if_polling(struct task_struct *p) | |
422 | { | |
423 | return false; | |
424 | } | |
425 | #endif | |
fd99f91a PZ |
426 | #endif |
427 | ||
76751049 PZ |
428 | void wake_q_add(struct wake_q_head *head, struct task_struct *task) |
429 | { | |
430 | struct wake_q_node *node = &task->wake_q; | |
431 | ||
432 | /* | |
433 | * Atomically grab the task, if ->wake_q is !nil already it means | |
434 | * its already queued (either by us or someone else) and will get the | |
435 | * wakeup due to that. | |
436 | * | |
437 | * This cmpxchg() implies a full barrier, which pairs with the write | |
58fe9c46 | 438 | * barrier implied by the wakeup in wake_up_q(). |
76751049 PZ |
439 | */ |
440 | if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL)) | |
441 | return; | |
442 | ||
443 | get_task_struct(task); | |
444 | ||
445 | /* | |
446 | * The head is context local, there can be no concurrency. | |
447 | */ | |
448 | *head->lastp = node; | |
449 | head->lastp = &node->next; | |
450 | } | |
451 | ||
452 | void wake_up_q(struct wake_q_head *head) | |
453 | { | |
454 | struct wake_q_node *node = head->first; | |
455 | ||
456 | while (node != WAKE_Q_TAIL) { | |
457 | struct task_struct *task; | |
458 | ||
459 | task = container_of(node, struct task_struct, wake_q); | |
460 | BUG_ON(!task); | |
461 | /* task can safely be re-inserted now */ | |
462 | node = node->next; | |
463 | task->wake_q.next = NULL; | |
464 | ||
465 | /* | |
466 | * wake_up_process() implies a wmb() to pair with the queueing | |
467 | * in wake_q_add() so as not to miss wakeups. | |
468 | */ | |
469 | wake_up_process(task); | |
470 | put_task_struct(task); | |
471 | } | |
472 | } | |
473 | ||
c24d20db | 474 | /* |
8875125e | 475 | * resched_curr - mark rq's current task 'to be rescheduled now'. |
c24d20db IM |
476 | * |
477 | * On UP this means the setting of the need_resched flag, on SMP it | |
478 | * might also involve a cross-CPU call to trigger the scheduler on | |
479 | * the target CPU. | |
480 | */ | |
8875125e | 481 | void resched_curr(struct rq *rq) |
c24d20db | 482 | { |
8875125e | 483 | struct task_struct *curr = rq->curr; |
c24d20db IM |
484 | int cpu; |
485 | ||
8875125e | 486 | lockdep_assert_held(&rq->lock); |
c24d20db | 487 | |
8875125e | 488 | if (test_tsk_need_resched(curr)) |
c24d20db IM |
489 | return; |
490 | ||
8875125e | 491 | cpu = cpu_of(rq); |
fd99f91a | 492 | |
f27dde8d | 493 | if (cpu == smp_processor_id()) { |
8875125e | 494 | set_tsk_need_resched(curr); |
f27dde8d | 495 | set_preempt_need_resched(); |
c24d20db | 496 | return; |
f27dde8d | 497 | } |
c24d20db | 498 | |
8875125e | 499 | if (set_nr_and_not_polling(curr)) |
c24d20db | 500 | smp_send_reschedule(cpu); |
dfc68f29 AL |
501 | else |
502 | trace_sched_wake_idle_without_ipi(cpu); | |
c24d20db IM |
503 | } |
504 | ||
029632fb | 505 | void resched_cpu(int cpu) |
c24d20db IM |
506 | { |
507 | struct rq *rq = cpu_rq(cpu); | |
508 | unsigned long flags; | |
509 | ||
05fa785c | 510 | if (!raw_spin_trylock_irqsave(&rq->lock, flags)) |
c24d20db | 511 | return; |
8875125e | 512 | resched_curr(rq); |
05fa785c | 513 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
c24d20db | 514 | } |
06d8308c | 515 | |
b021fe3e | 516 | #ifdef CONFIG_SMP |
3451d024 | 517 | #ifdef CONFIG_NO_HZ_COMMON |
83cd4fe2 VP |
518 | /* |
519 | * In the semi idle case, use the nearest busy cpu for migrating timers | |
520 | * from an idle cpu. This is good for power-savings. | |
521 | * | |
522 | * We don't do similar optimization for completely idle system, as | |
523 | * selecting an idle cpu will add more delays to the timers than intended | |
524 | * (as that cpu's timer base may not be uptodate wrt jiffies etc). | |
525 | */ | |
bc7a34b8 | 526 | int get_nohz_timer_target(void) |
83cd4fe2 | 527 | { |
bc7a34b8 | 528 | int i, cpu = smp_processor_id(); |
83cd4fe2 VP |
529 | struct sched_domain *sd; |
530 | ||
9642d18e | 531 | if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu)) |
6201b4d6 VK |
532 | return cpu; |
533 | ||
057f3fad | 534 | rcu_read_lock(); |
83cd4fe2 | 535 | for_each_domain(cpu, sd) { |
057f3fad | 536 | for_each_cpu(i, sched_domain_span(sd)) { |
44496922 WL |
537 | if (cpu == i) |
538 | continue; | |
539 | ||
540 | if (!idle_cpu(i) && is_housekeeping_cpu(i)) { | |
057f3fad PZ |
541 | cpu = i; |
542 | goto unlock; | |
543 | } | |
544 | } | |
83cd4fe2 | 545 | } |
9642d18e VH |
546 | |
547 | if (!is_housekeeping_cpu(cpu)) | |
548 | cpu = housekeeping_any_cpu(); | |
057f3fad PZ |
549 | unlock: |
550 | rcu_read_unlock(); | |
83cd4fe2 VP |
551 | return cpu; |
552 | } | |
06d8308c TG |
553 | /* |
554 | * When add_timer_on() enqueues a timer into the timer wheel of an | |
555 | * idle CPU then this timer might expire before the next timer event | |
556 | * which is scheduled to wake up that CPU. In case of a completely | |
557 | * idle system the next event might even be infinite time into the | |
558 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and | |
559 | * leaves the inner idle loop so the newly added timer is taken into | |
560 | * account when the CPU goes back to idle and evaluates the timer | |
561 | * wheel for the next timer event. | |
562 | */ | |
1c20091e | 563 | static void wake_up_idle_cpu(int cpu) |
06d8308c TG |
564 | { |
565 | struct rq *rq = cpu_rq(cpu); | |
566 | ||
567 | if (cpu == smp_processor_id()) | |
568 | return; | |
569 | ||
67b9ca70 | 570 | if (set_nr_and_not_polling(rq->idle)) |
06d8308c | 571 | smp_send_reschedule(cpu); |
dfc68f29 AL |
572 | else |
573 | trace_sched_wake_idle_without_ipi(cpu); | |
45bf76df IM |
574 | } |
575 | ||
c5bfece2 | 576 | static bool wake_up_full_nohz_cpu(int cpu) |
1c20091e | 577 | { |
53c5fa16 FW |
578 | /* |
579 | * We just need the target to call irq_exit() and re-evaluate | |
580 | * the next tick. The nohz full kick at least implies that. | |
581 | * If needed we can still optimize that later with an | |
582 | * empty IRQ. | |
583 | */ | |
379d9ecb PM |
584 | if (cpu_is_offline(cpu)) |
585 | return true; /* Don't try to wake offline CPUs. */ | |
c5bfece2 | 586 | if (tick_nohz_full_cpu(cpu)) { |
1c20091e FW |
587 | if (cpu != smp_processor_id() || |
588 | tick_nohz_tick_stopped()) | |
53c5fa16 | 589 | tick_nohz_full_kick_cpu(cpu); |
1c20091e FW |
590 | return true; |
591 | } | |
592 | ||
593 | return false; | |
594 | } | |
595 | ||
379d9ecb PM |
596 | /* |
597 | * Wake up the specified CPU. If the CPU is going offline, it is the | |
598 | * caller's responsibility to deal with the lost wakeup, for example, | |
599 | * by hooking into the CPU_DEAD notifier like timers and hrtimers do. | |
600 | */ | |
1c20091e FW |
601 | void wake_up_nohz_cpu(int cpu) |
602 | { | |
c5bfece2 | 603 | if (!wake_up_full_nohz_cpu(cpu)) |
1c20091e FW |
604 | wake_up_idle_cpu(cpu); |
605 | } | |
606 | ||
ca38062e | 607 | static inline bool got_nohz_idle_kick(void) |
45bf76df | 608 | { |
1c792db7 | 609 | int cpu = smp_processor_id(); |
873b4c65 VG |
610 | |
611 | if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) | |
612 | return false; | |
613 | ||
614 | if (idle_cpu(cpu) && !need_resched()) | |
615 | return true; | |
616 | ||
617 | /* | |
618 | * We can't run Idle Load Balance on this CPU for this time so we | |
619 | * cancel it and clear NOHZ_BALANCE_KICK | |
620 | */ | |
621 | clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); | |
622 | return false; | |
45bf76df IM |
623 | } |
624 | ||
3451d024 | 625 | #else /* CONFIG_NO_HZ_COMMON */ |
45bf76df | 626 | |
ca38062e | 627 | static inline bool got_nohz_idle_kick(void) |
2069dd75 | 628 | { |
ca38062e | 629 | return false; |
2069dd75 PZ |
630 | } |
631 | ||
3451d024 | 632 | #endif /* CONFIG_NO_HZ_COMMON */ |
d842de87 | 633 | |
ce831b38 | 634 | #ifdef CONFIG_NO_HZ_FULL |
76d92ac3 | 635 | bool sched_can_stop_tick(struct rq *rq) |
ce831b38 | 636 | { |
76d92ac3 FW |
637 | int fifo_nr_running; |
638 | ||
639 | /* Deadline tasks, even if single, need the tick */ | |
640 | if (rq->dl.dl_nr_running) | |
641 | return false; | |
642 | ||
1e78cdbd | 643 | /* |
2548d546 PZ |
644 | * If there are more than one RR tasks, we need the tick to effect the |
645 | * actual RR behaviour. | |
1e78cdbd | 646 | */ |
76d92ac3 FW |
647 | if (rq->rt.rr_nr_running) { |
648 | if (rq->rt.rr_nr_running == 1) | |
649 | return true; | |
650 | else | |
651 | return false; | |
1e78cdbd RR |
652 | } |
653 | ||
2548d546 PZ |
654 | /* |
655 | * If there's no RR tasks, but FIFO tasks, we can skip the tick, no | |
656 | * forced preemption between FIFO tasks. | |
657 | */ | |
658 | fifo_nr_running = rq->rt.rt_nr_running - rq->rt.rr_nr_running; | |
659 | if (fifo_nr_running) | |
660 | return true; | |
661 | ||
662 | /* | |
663 | * If there are no DL,RR/FIFO tasks, there must only be CFS tasks left; | |
664 | * if there's more than one we need the tick for involuntary | |
665 | * preemption. | |
666 | */ | |
667 | if (rq->nr_running > 1) | |
541b8264 | 668 | return false; |
ce831b38 | 669 | |
541b8264 | 670 | return true; |
ce831b38 FW |
671 | } |
672 | #endif /* CONFIG_NO_HZ_FULL */ | |
d842de87 | 673 | |
029632fb | 674 | void sched_avg_update(struct rq *rq) |
18d95a28 | 675 | { |
e9e9250b PZ |
676 | s64 period = sched_avg_period(); |
677 | ||
78becc27 | 678 | while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { |
0d98bb26 WD |
679 | /* |
680 | * Inline assembly required to prevent the compiler | |
681 | * optimising this loop into a divmod call. | |
682 | * See __iter_div_u64_rem() for another example of this. | |
683 | */ | |
684 | asm("" : "+rm" (rq->age_stamp)); | |
e9e9250b PZ |
685 | rq->age_stamp += period; |
686 | rq->rt_avg /= 2; | |
687 | } | |
18d95a28 PZ |
688 | } |
689 | ||
6d6bc0ad | 690 | #endif /* CONFIG_SMP */ |
18d95a28 | 691 | |
a790de99 PT |
692 | #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ |
693 | (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) | |
c09595f6 | 694 | /* |
8277434e PT |
695 | * Iterate task_group tree rooted at *from, calling @down when first entering a |
696 | * node and @up when leaving it for the final time. | |
697 | * | |
698 | * Caller must hold rcu_lock or sufficient equivalent. | |
c09595f6 | 699 | */ |
029632fb | 700 | int walk_tg_tree_from(struct task_group *from, |
8277434e | 701 | tg_visitor down, tg_visitor up, void *data) |
c09595f6 PZ |
702 | { |
703 | struct task_group *parent, *child; | |
eb755805 | 704 | int ret; |
c09595f6 | 705 | |
8277434e PT |
706 | parent = from; |
707 | ||
c09595f6 | 708 | down: |
eb755805 PZ |
709 | ret = (*down)(parent, data); |
710 | if (ret) | |
8277434e | 711 | goto out; |
c09595f6 PZ |
712 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
713 | parent = child; | |
714 | goto down; | |
715 | ||
716 | up: | |
717 | continue; | |
718 | } | |
eb755805 | 719 | ret = (*up)(parent, data); |
8277434e PT |
720 | if (ret || parent == from) |
721 | goto out; | |
c09595f6 PZ |
722 | |
723 | child = parent; | |
724 | parent = parent->parent; | |
725 | if (parent) | |
726 | goto up; | |
8277434e | 727 | out: |
eb755805 | 728 | return ret; |
c09595f6 PZ |
729 | } |
730 | ||
029632fb | 731 | int tg_nop(struct task_group *tg, void *data) |
eb755805 | 732 | { |
e2b245f8 | 733 | return 0; |
eb755805 | 734 | } |
18d95a28 PZ |
735 | #endif |
736 | ||
45bf76df IM |
737 | static void set_load_weight(struct task_struct *p) |
738 | { | |
f05998d4 NR |
739 | int prio = p->static_prio - MAX_RT_PRIO; |
740 | struct load_weight *load = &p->se.load; | |
741 | ||
dd41f596 IM |
742 | /* |
743 | * SCHED_IDLE tasks get minimal weight: | |
744 | */ | |
20f9cd2a | 745 | if (idle_policy(p->policy)) { |
c8b28116 | 746 | load->weight = scale_load(WEIGHT_IDLEPRIO); |
f05998d4 | 747 | load->inv_weight = WMULT_IDLEPRIO; |
dd41f596 IM |
748 | return; |
749 | } | |
71f8bd46 | 750 | |
ed82b8a1 AK |
751 | load->weight = scale_load(sched_prio_to_weight[prio]); |
752 | load->inv_weight = sched_prio_to_wmult[prio]; | |
71f8bd46 IM |
753 | } |
754 | ||
1de64443 | 755 | static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags) |
2087a1ad | 756 | { |
a64692a3 | 757 | update_rq_clock(rq); |
1de64443 PZ |
758 | if (!(flags & ENQUEUE_RESTORE)) |
759 | sched_info_queued(rq, p); | |
371fd7e7 | 760 | p->sched_class->enqueue_task(rq, p, flags); |
71f8bd46 IM |
761 | } |
762 | ||
1de64443 | 763 | static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags) |
71f8bd46 | 764 | { |
a64692a3 | 765 | update_rq_clock(rq); |
1de64443 PZ |
766 | if (!(flags & DEQUEUE_SAVE)) |
767 | sched_info_dequeued(rq, p); | |
371fd7e7 | 768 | p->sched_class->dequeue_task(rq, p, flags); |
71f8bd46 IM |
769 | } |
770 | ||
029632fb | 771 | void activate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
772 | { |
773 | if (task_contributes_to_load(p)) | |
774 | rq->nr_uninterruptible--; | |
775 | ||
371fd7e7 | 776 | enqueue_task(rq, p, flags); |
1e3c88bd PZ |
777 | } |
778 | ||
029632fb | 779 | void deactivate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
780 | { |
781 | if (task_contributes_to_load(p)) | |
782 | rq->nr_uninterruptible++; | |
783 | ||
371fd7e7 | 784 | dequeue_task(rq, p, flags); |
1e3c88bd PZ |
785 | } |
786 | ||
fe44d621 | 787 | static void update_rq_clock_task(struct rq *rq, s64 delta) |
aa483808 | 788 | { |
095c0aa8 GC |
789 | /* |
790 | * In theory, the compile should just see 0 here, and optimize out the call | |
791 | * to sched_rt_avg_update. But I don't trust it... | |
792 | */ | |
793 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) | |
794 | s64 steal = 0, irq_delta = 0; | |
795 | #endif | |
796 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING | |
8e92c201 | 797 | irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; |
fe44d621 PZ |
798 | |
799 | /* | |
800 | * Since irq_time is only updated on {soft,}irq_exit, we might run into | |
801 | * this case when a previous update_rq_clock() happened inside a | |
802 | * {soft,}irq region. | |
803 | * | |
804 | * When this happens, we stop ->clock_task and only update the | |
805 | * prev_irq_time stamp to account for the part that fit, so that a next | |
806 | * update will consume the rest. This ensures ->clock_task is | |
807 | * monotonic. | |
808 | * | |
809 | * It does however cause some slight miss-attribution of {soft,}irq | |
810 | * time, a more accurate solution would be to update the irq_time using | |
811 | * the current rq->clock timestamp, except that would require using | |
812 | * atomic ops. | |
813 | */ | |
814 | if (irq_delta > delta) | |
815 | irq_delta = delta; | |
816 | ||
817 | rq->prev_irq_time += irq_delta; | |
818 | delta -= irq_delta; | |
095c0aa8 GC |
819 | #endif |
820 | #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING | |
c5905afb | 821 | if (static_key_false((¶virt_steal_rq_enabled))) { |
095c0aa8 GC |
822 | steal = paravirt_steal_clock(cpu_of(rq)); |
823 | steal -= rq->prev_steal_time_rq; | |
824 | ||
825 | if (unlikely(steal > delta)) | |
826 | steal = delta; | |
827 | ||
095c0aa8 | 828 | rq->prev_steal_time_rq += steal; |
095c0aa8 GC |
829 | delta -= steal; |
830 | } | |
831 | #endif | |
832 | ||
fe44d621 PZ |
833 | rq->clock_task += delta; |
834 | ||
095c0aa8 | 835 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) |
5d4dfddd | 836 | if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) |
095c0aa8 GC |
837 | sched_rt_avg_update(rq, irq_delta + steal); |
838 | #endif | |
aa483808 VP |
839 | } |
840 | ||
34f971f6 PZ |
841 | void sched_set_stop_task(int cpu, struct task_struct *stop) |
842 | { | |
843 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
844 | struct task_struct *old_stop = cpu_rq(cpu)->stop; | |
845 | ||
846 | if (stop) { | |
847 | /* | |
848 | * Make it appear like a SCHED_FIFO task, its something | |
849 | * userspace knows about and won't get confused about. | |
850 | * | |
851 | * Also, it will make PI more or less work without too | |
852 | * much confusion -- but then, stop work should not | |
853 | * rely on PI working anyway. | |
854 | */ | |
855 | sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); | |
856 | ||
857 | stop->sched_class = &stop_sched_class; | |
858 | } | |
859 | ||
860 | cpu_rq(cpu)->stop = stop; | |
861 | ||
862 | if (old_stop) { | |
863 | /* | |
864 | * Reset it back to a normal scheduling class so that | |
865 | * it can die in pieces. | |
866 | */ | |
867 | old_stop->sched_class = &rt_sched_class; | |
868 | } | |
869 | } | |
870 | ||
14531189 | 871 | /* |
dd41f596 | 872 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 873 | */ |
14531189 IM |
874 | static inline int __normal_prio(struct task_struct *p) |
875 | { | |
dd41f596 | 876 | return p->static_prio; |
14531189 IM |
877 | } |
878 | ||
b29739f9 IM |
879 | /* |
880 | * Calculate the expected normal priority: i.e. priority | |
881 | * without taking RT-inheritance into account. Might be | |
882 | * boosted by interactivity modifiers. Changes upon fork, | |
883 | * setprio syscalls, and whenever the interactivity | |
884 | * estimator recalculates. | |
885 | */ | |
36c8b586 | 886 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
887 | { |
888 | int prio; | |
889 | ||
aab03e05 DF |
890 | if (task_has_dl_policy(p)) |
891 | prio = MAX_DL_PRIO-1; | |
892 | else if (task_has_rt_policy(p)) | |
b29739f9 IM |
893 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
894 | else | |
895 | prio = __normal_prio(p); | |
896 | return prio; | |
897 | } | |
898 | ||
899 | /* | |
900 | * Calculate the current priority, i.e. the priority | |
901 | * taken into account by the scheduler. This value might | |
902 | * be boosted by RT tasks, or might be boosted by | |
903 | * interactivity modifiers. Will be RT if the task got | |
904 | * RT-boosted. If not then it returns p->normal_prio. | |
905 | */ | |
36c8b586 | 906 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
907 | { |
908 | p->normal_prio = normal_prio(p); | |
909 | /* | |
910 | * If we are RT tasks or we were boosted to RT priority, | |
911 | * keep the priority unchanged. Otherwise, update priority | |
912 | * to the normal priority: | |
913 | */ | |
914 | if (!rt_prio(p->prio)) | |
915 | return p->normal_prio; | |
916 | return p->prio; | |
917 | } | |
918 | ||
1da177e4 LT |
919 | /** |
920 | * task_curr - is this task currently executing on a CPU? | |
921 | * @p: the task in question. | |
e69f6186 YB |
922 | * |
923 | * Return: 1 if the task is currently executing. 0 otherwise. | |
1da177e4 | 924 | */ |
36c8b586 | 925 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
926 | { |
927 | return cpu_curr(task_cpu(p)) == p; | |
928 | } | |
929 | ||
67dfa1b7 | 930 | /* |
4c9a4bc8 PZ |
931 | * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock, |
932 | * use the balance_callback list if you want balancing. | |
933 | * | |
934 | * this means any call to check_class_changed() must be followed by a call to | |
935 | * balance_callback(). | |
67dfa1b7 | 936 | */ |
cb469845 SR |
937 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
938 | const struct sched_class *prev_class, | |
da7a735e | 939 | int oldprio) |
cb469845 SR |
940 | { |
941 | if (prev_class != p->sched_class) { | |
942 | if (prev_class->switched_from) | |
da7a735e | 943 | prev_class->switched_from(rq, p); |
4c9a4bc8 | 944 | |
da7a735e | 945 | p->sched_class->switched_to(rq, p); |
2d3d891d | 946 | } else if (oldprio != p->prio || dl_task(p)) |
da7a735e | 947 | p->sched_class->prio_changed(rq, p, oldprio); |
cb469845 SR |
948 | } |
949 | ||
029632fb | 950 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
1e5a7405 PZ |
951 | { |
952 | const struct sched_class *class; | |
953 | ||
954 | if (p->sched_class == rq->curr->sched_class) { | |
955 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); | |
956 | } else { | |
957 | for_each_class(class) { | |
958 | if (class == rq->curr->sched_class) | |
959 | break; | |
960 | if (class == p->sched_class) { | |
8875125e | 961 | resched_curr(rq); |
1e5a7405 PZ |
962 | break; |
963 | } | |
964 | } | |
965 | } | |
966 | ||
967 | /* | |
968 | * A queue event has occurred, and we're going to schedule. In | |
969 | * this case, we can save a useless back to back clock update. | |
970 | */ | |
da0c1e65 | 971 | if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr)) |
9edfbfed | 972 | rq_clock_skip_update(rq, true); |
1e5a7405 PZ |
973 | } |
974 | ||
1da177e4 | 975 | #ifdef CONFIG_SMP |
5cc389bc PZ |
976 | /* |
977 | * This is how migration works: | |
978 | * | |
979 | * 1) we invoke migration_cpu_stop() on the target CPU using | |
980 | * stop_one_cpu(). | |
981 | * 2) stopper starts to run (implicitly forcing the migrated thread | |
982 | * off the CPU) | |
983 | * 3) it checks whether the migrated task is still in the wrong runqueue. | |
984 | * 4) if it's in the wrong runqueue then the migration thread removes | |
985 | * it and puts it into the right queue. | |
986 | * 5) stopper completes and stop_one_cpu() returns and the migration | |
987 | * is done. | |
988 | */ | |
989 | ||
990 | /* | |
991 | * move_queued_task - move a queued task to new rq. | |
992 | * | |
993 | * Returns (locked) new rq. Old rq's lock is released. | |
994 | */ | |
5e16bbc2 | 995 | static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int new_cpu) |
5cc389bc | 996 | { |
5cc389bc PZ |
997 | lockdep_assert_held(&rq->lock); |
998 | ||
5cc389bc | 999 | p->on_rq = TASK_ON_RQ_MIGRATING; |
3ea94de1 | 1000 | dequeue_task(rq, p, 0); |
5cc389bc PZ |
1001 | set_task_cpu(p, new_cpu); |
1002 | raw_spin_unlock(&rq->lock); | |
1003 | ||
1004 | rq = cpu_rq(new_cpu); | |
1005 | ||
1006 | raw_spin_lock(&rq->lock); | |
1007 | BUG_ON(task_cpu(p) != new_cpu); | |
5cc389bc | 1008 | enqueue_task(rq, p, 0); |
3ea94de1 | 1009 | p->on_rq = TASK_ON_RQ_QUEUED; |
5cc389bc PZ |
1010 | check_preempt_curr(rq, p, 0); |
1011 | ||
1012 | return rq; | |
1013 | } | |
1014 | ||
1015 | struct migration_arg { | |
1016 | struct task_struct *task; | |
1017 | int dest_cpu; | |
1018 | }; | |
1019 | ||
1020 | /* | |
1021 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
1022 | * this because either it can't run here any more (set_cpus_allowed() | |
1023 | * away from this CPU, or CPU going down), or because we're | |
1024 | * attempting to rebalance this task on exec (sched_exec). | |
1025 | * | |
1026 | * So we race with normal scheduler movements, but that's OK, as long | |
1027 | * as the task is no longer on this CPU. | |
5cc389bc | 1028 | */ |
5e16bbc2 | 1029 | static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_cpu) |
5cc389bc | 1030 | { |
5cc389bc | 1031 | if (unlikely(!cpu_active(dest_cpu))) |
5e16bbc2 | 1032 | return rq; |
5cc389bc PZ |
1033 | |
1034 | /* Affinity changed (again). */ | |
1035 | if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) | |
5e16bbc2 | 1036 | return rq; |
5cc389bc | 1037 | |
5e16bbc2 PZ |
1038 | rq = move_queued_task(rq, p, dest_cpu); |
1039 | ||
1040 | return rq; | |
5cc389bc PZ |
1041 | } |
1042 | ||
1043 | /* | |
1044 | * migration_cpu_stop - this will be executed by a highprio stopper thread | |
1045 | * and performs thread migration by bumping thread off CPU then | |
1046 | * 'pushing' onto another runqueue. | |
1047 | */ | |
1048 | static int migration_cpu_stop(void *data) | |
1049 | { | |
1050 | struct migration_arg *arg = data; | |
5e16bbc2 PZ |
1051 | struct task_struct *p = arg->task; |
1052 | struct rq *rq = this_rq(); | |
5cc389bc PZ |
1053 | |
1054 | /* | |
1055 | * The original target cpu might have gone down and we might | |
1056 | * be on another cpu but it doesn't matter. | |
1057 | */ | |
1058 | local_irq_disable(); | |
1059 | /* | |
1060 | * We need to explicitly wake pending tasks before running | |
1061 | * __migrate_task() such that we will not miss enforcing cpus_allowed | |
1062 | * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. | |
1063 | */ | |
1064 | sched_ttwu_pending(); | |
5e16bbc2 PZ |
1065 | |
1066 | raw_spin_lock(&p->pi_lock); | |
1067 | raw_spin_lock(&rq->lock); | |
1068 | /* | |
1069 | * If task_rq(p) != rq, it cannot be migrated here, because we're | |
1070 | * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because | |
1071 | * we're holding p->pi_lock. | |
1072 | */ | |
1073 | if (task_rq(p) == rq && task_on_rq_queued(p)) | |
1074 | rq = __migrate_task(rq, p, arg->dest_cpu); | |
1075 | raw_spin_unlock(&rq->lock); | |
1076 | raw_spin_unlock(&p->pi_lock); | |
1077 | ||
5cc389bc PZ |
1078 | local_irq_enable(); |
1079 | return 0; | |
1080 | } | |
1081 | ||
c5b28038 PZ |
1082 | /* |
1083 | * sched_class::set_cpus_allowed must do the below, but is not required to | |
1084 | * actually call this function. | |
1085 | */ | |
1086 | void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask) | |
5cc389bc | 1087 | { |
5cc389bc PZ |
1088 | cpumask_copy(&p->cpus_allowed, new_mask); |
1089 | p->nr_cpus_allowed = cpumask_weight(new_mask); | |
1090 | } | |
1091 | ||
c5b28038 PZ |
1092 | void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) |
1093 | { | |
6c37067e PZ |
1094 | struct rq *rq = task_rq(p); |
1095 | bool queued, running; | |
1096 | ||
c5b28038 | 1097 | lockdep_assert_held(&p->pi_lock); |
6c37067e PZ |
1098 | |
1099 | queued = task_on_rq_queued(p); | |
1100 | running = task_current(rq, p); | |
1101 | ||
1102 | if (queued) { | |
1103 | /* | |
1104 | * Because __kthread_bind() calls this on blocked tasks without | |
1105 | * holding rq->lock. | |
1106 | */ | |
1107 | lockdep_assert_held(&rq->lock); | |
1de64443 | 1108 | dequeue_task(rq, p, DEQUEUE_SAVE); |
6c37067e PZ |
1109 | } |
1110 | if (running) | |
1111 | put_prev_task(rq, p); | |
1112 | ||
c5b28038 | 1113 | p->sched_class->set_cpus_allowed(p, new_mask); |
6c37067e PZ |
1114 | |
1115 | if (running) | |
1116 | p->sched_class->set_curr_task(rq); | |
1117 | if (queued) | |
1de64443 | 1118 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
c5b28038 PZ |
1119 | } |
1120 | ||
5cc389bc PZ |
1121 | /* |
1122 | * Change a given task's CPU affinity. Migrate the thread to a | |
1123 | * proper CPU and schedule it away if the CPU it's executing on | |
1124 | * is removed from the allowed bitmask. | |
1125 | * | |
1126 | * NOTE: the caller must have a valid reference to the task, the | |
1127 | * task must not exit() & deallocate itself prematurely. The | |
1128 | * call is not atomic; no spinlocks may be held. | |
1129 | */ | |
25834c73 PZ |
1130 | static int __set_cpus_allowed_ptr(struct task_struct *p, |
1131 | const struct cpumask *new_mask, bool check) | |
5cc389bc | 1132 | { |
e9d867a6 | 1133 | const struct cpumask *cpu_valid_mask = cpu_active_mask; |
5cc389bc | 1134 | unsigned int dest_cpu; |
eb580751 PZ |
1135 | struct rq_flags rf; |
1136 | struct rq *rq; | |
5cc389bc PZ |
1137 | int ret = 0; |
1138 | ||
eb580751 | 1139 | rq = task_rq_lock(p, &rf); |
5cc389bc | 1140 | |
e9d867a6 PZI |
1141 | if (p->flags & PF_KTHREAD) { |
1142 | /* | |
1143 | * Kernel threads are allowed on online && !active CPUs | |
1144 | */ | |
1145 | cpu_valid_mask = cpu_online_mask; | |
1146 | } | |
1147 | ||
25834c73 PZ |
1148 | /* |
1149 | * Must re-check here, to close a race against __kthread_bind(), | |
1150 | * sched_setaffinity() is not guaranteed to observe the flag. | |
1151 | */ | |
1152 | if (check && (p->flags & PF_NO_SETAFFINITY)) { | |
1153 | ret = -EINVAL; | |
1154 | goto out; | |
1155 | } | |
1156 | ||
5cc389bc PZ |
1157 | if (cpumask_equal(&p->cpus_allowed, new_mask)) |
1158 | goto out; | |
1159 | ||
e9d867a6 | 1160 | if (!cpumask_intersects(new_mask, cpu_valid_mask)) { |
5cc389bc PZ |
1161 | ret = -EINVAL; |
1162 | goto out; | |
1163 | } | |
1164 | ||
1165 | do_set_cpus_allowed(p, new_mask); | |
1166 | ||
e9d867a6 PZI |
1167 | if (p->flags & PF_KTHREAD) { |
1168 | /* | |
1169 | * For kernel threads that do indeed end up on online && | |
1170 | * !active we want to ensure they are strict per-cpu threads. | |
1171 | */ | |
1172 | WARN_ON(cpumask_intersects(new_mask, cpu_online_mask) && | |
1173 | !cpumask_intersects(new_mask, cpu_active_mask) && | |
1174 | p->nr_cpus_allowed != 1); | |
1175 | } | |
1176 | ||
5cc389bc PZ |
1177 | /* Can the task run on the task's current CPU? If so, we're done */ |
1178 | if (cpumask_test_cpu(task_cpu(p), new_mask)) | |
1179 | goto out; | |
1180 | ||
e9d867a6 | 1181 | dest_cpu = cpumask_any_and(cpu_valid_mask, new_mask); |
5cc389bc PZ |
1182 | if (task_running(rq, p) || p->state == TASK_WAKING) { |
1183 | struct migration_arg arg = { p, dest_cpu }; | |
1184 | /* Need help from migration thread: drop lock and wait. */ | |
eb580751 | 1185 | task_rq_unlock(rq, p, &rf); |
5cc389bc PZ |
1186 | stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); |
1187 | tlb_migrate_finish(p->mm); | |
1188 | return 0; | |
cbce1a68 PZ |
1189 | } else if (task_on_rq_queued(p)) { |
1190 | /* | |
1191 | * OK, since we're going to drop the lock immediately | |
1192 | * afterwards anyway. | |
1193 | */ | |
e7904a28 | 1194 | lockdep_unpin_lock(&rq->lock, rf.cookie); |
5e16bbc2 | 1195 | rq = move_queued_task(rq, p, dest_cpu); |
e7904a28 | 1196 | lockdep_repin_lock(&rq->lock, rf.cookie); |
cbce1a68 | 1197 | } |
5cc389bc | 1198 | out: |
eb580751 | 1199 | task_rq_unlock(rq, p, &rf); |
5cc389bc PZ |
1200 | |
1201 | return ret; | |
1202 | } | |
25834c73 PZ |
1203 | |
1204 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) | |
1205 | { | |
1206 | return __set_cpus_allowed_ptr(p, new_mask, false); | |
1207 | } | |
5cc389bc PZ |
1208 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
1209 | ||
dd41f596 | 1210 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1211 | { |
e2912009 PZ |
1212 | #ifdef CONFIG_SCHED_DEBUG |
1213 | /* | |
1214 | * We should never call set_task_cpu() on a blocked task, | |
1215 | * ttwu() will sort out the placement. | |
1216 | */ | |
077614ee | 1217 | WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && |
e2336f6e | 1218 | !p->on_rq); |
0122ec5b | 1219 | |
3ea94de1 JP |
1220 | /* |
1221 | * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING, | |
1222 | * because schedstat_wait_{start,end} rebase migrating task's wait_start | |
1223 | * time relying on p->on_rq. | |
1224 | */ | |
1225 | WARN_ON_ONCE(p->state == TASK_RUNNING && | |
1226 | p->sched_class == &fair_sched_class && | |
1227 | (p->on_rq && !task_on_rq_migrating(p))); | |
1228 | ||
0122ec5b | 1229 | #ifdef CONFIG_LOCKDEP |
6c6c54e1 PZ |
1230 | /* |
1231 | * The caller should hold either p->pi_lock or rq->lock, when changing | |
1232 | * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. | |
1233 | * | |
1234 | * sched_move_task() holds both and thus holding either pins the cgroup, | |
8323f26c | 1235 | * see task_group(). |
6c6c54e1 PZ |
1236 | * |
1237 | * Furthermore, all task_rq users should acquire both locks, see | |
1238 | * task_rq_lock(). | |
1239 | */ | |
0122ec5b PZ |
1240 | WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || |
1241 | lockdep_is_held(&task_rq(p)->lock))); | |
1242 | #endif | |
e2912009 PZ |
1243 | #endif |
1244 | ||
de1d7286 | 1245 | trace_sched_migrate_task(p, new_cpu); |
cbc34ed1 | 1246 | |
0c69774e | 1247 | if (task_cpu(p) != new_cpu) { |
0a74bef8 | 1248 | if (p->sched_class->migrate_task_rq) |
5a4fd036 | 1249 | p->sched_class->migrate_task_rq(p); |
0c69774e | 1250 | p->se.nr_migrations++; |
ff303e66 | 1251 | perf_event_task_migrate(p); |
0c69774e | 1252 | } |
dd41f596 IM |
1253 | |
1254 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1255 | } |
1256 | ||
ac66f547 PZ |
1257 | static void __migrate_swap_task(struct task_struct *p, int cpu) |
1258 | { | |
da0c1e65 | 1259 | if (task_on_rq_queued(p)) { |
ac66f547 PZ |
1260 | struct rq *src_rq, *dst_rq; |
1261 | ||
1262 | src_rq = task_rq(p); | |
1263 | dst_rq = cpu_rq(cpu); | |
1264 | ||
3ea94de1 | 1265 | p->on_rq = TASK_ON_RQ_MIGRATING; |
ac66f547 PZ |
1266 | deactivate_task(src_rq, p, 0); |
1267 | set_task_cpu(p, cpu); | |
1268 | activate_task(dst_rq, p, 0); | |
3ea94de1 | 1269 | p->on_rq = TASK_ON_RQ_QUEUED; |
ac66f547 PZ |
1270 | check_preempt_curr(dst_rq, p, 0); |
1271 | } else { | |
1272 | /* | |
1273 | * Task isn't running anymore; make it appear like we migrated | |
1274 | * it before it went to sleep. This means on wakeup we make the | |
a1fd4656 | 1275 | * previous cpu our target instead of where it really is. |
ac66f547 PZ |
1276 | */ |
1277 | p->wake_cpu = cpu; | |
1278 | } | |
1279 | } | |
1280 | ||
1281 | struct migration_swap_arg { | |
1282 | struct task_struct *src_task, *dst_task; | |
1283 | int src_cpu, dst_cpu; | |
1284 | }; | |
1285 | ||
1286 | static int migrate_swap_stop(void *data) | |
1287 | { | |
1288 | struct migration_swap_arg *arg = data; | |
1289 | struct rq *src_rq, *dst_rq; | |
1290 | int ret = -EAGAIN; | |
1291 | ||
62694cd5 PZ |
1292 | if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu)) |
1293 | return -EAGAIN; | |
1294 | ||
ac66f547 PZ |
1295 | src_rq = cpu_rq(arg->src_cpu); |
1296 | dst_rq = cpu_rq(arg->dst_cpu); | |
1297 | ||
74602315 PZ |
1298 | double_raw_lock(&arg->src_task->pi_lock, |
1299 | &arg->dst_task->pi_lock); | |
ac66f547 | 1300 | double_rq_lock(src_rq, dst_rq); |
62694cd5 | 1301 | |
ac66f547 PZ |
1302 | if (task_cpu(arg->dst_task) != arg->dst_cpu) |
1303 | goto unlock; | |
1304 | ||
1305 | if (task_cpu(arg->src_task) != arg->src_cpu) | |
1306 | goto unlock; | |
1307 | ||
1308 | if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) | |
1309 | goto unlock; | |
1310 | ||
1311 | if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) | |
1312 | goto unlock; | |
1313 | ||
1314 | __migrate_swap_task(arg->src_task, arg->dst_cpu); | |
1315 | __migrate_swap_task(arg->dst_task, arg->src_cpu); | |
1316 | ||
1317 | ret = 0; | |
1318 | ||
1319 | unlock: | |
1320 | double_rq_unlock(src_rq, dst_rq); | |
74602315 PZ |
1321 | raw_spin_unlock(&arg->dst_task->pi_lock); |
1322 | raw_spin_unlock(&arg->src_task->pi_lock); | |
ac66f547 PZ |
1323 | |
1324 | return ret; | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * Cross migrate two tasks | |
1329 | */ | |
1330 | int migrate_swap(struct task_struct *cur, struct task_struct *p) | |
1331 | { | |
1332 | struct migration_swap_arg arg; | |
1333 | int ret = -EINVAL; | |
1334 | ||
ac66f547 PZ |
1335 | arg = (struct migration_swap_arg){ |
1336 | .src_task = cur, | |
1337 | .src_cpu = task_cpu(cur), | |
1338 | .dst_task = p, | |
1339 | .dst_cpu = task_cpu(p), | |
1340 | }; | |
1341 | ||
1342 | if (arg.src_cpu == arg.dst_cpu) | |
1343 | goto out; | |
1344 | ||
6acce3ef PZ |
1345 | /* |
1346 | * These three tests are all lockless; this is OK since all of them | |
1347 | * will be re-checked with proper locks held further down the line. | |
1348 | */ | |
ac66f547 PZ |
1349 | if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) |
1350 | goto out; | |
1351 | ||
1352 | if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) | |
1353 | goto out; | |
1354 | ||
1355 | if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) | |
1356 | goto out; | |
1357 | ||
286549dc | 1358 | trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); |
ac66f547 PZ |
1359 | ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); |
1360 | ||
1361 | out: | |
ac66f547 PZ |
1362 | return ret; |
1363 | } | |
1364 | ||
1da177e4 LT |
1365 | /* |
1366 | * wait_task_inactive - wait for a thread to unschedule. | |
1367 | * | |
85ba2d86 RM |
1368 | * If @match_state is nonzero, it's the @p->state value just checked and |
1369 | * not expected to change. If it changes, i.e. @p might have woken up, | |
1370 | * then return zero. When we succeed in waiting for @p to be off its CPU, | |
1371 | * we return a positive number (its total switch count). If a second call | |
1372 | * a short while later returns the same number, the caller can be sure that | |
1373 | * @p has remained unscheduled the whole time. | |
1374 | * | |
1da177e4 LT |
1375 | * The caller must ensure that the task *will* unschedule sometime soon, |
1376 | * else this function might spin for a *long* time. This function can't | |
1377 | * be called with interrupts off, or it may introduce deadlock with | |
1378 | * smp_call_function() if an IPI is sent by the same process we are | |
1379 | * waiting to become inactive. | |
1380 | */ | |
85ba2d86 | 1381 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
1da177e4 | 1382 | { |
da0c1e65 | 1383 | int running, queued; |
eb580751 | 1384 | struct rq_flags rf; |
85ba2d86 | 1385 | unsigned long ncsw; |
70b97a7f | 1386 | struct rq *rq; |
1da177e4 | 1387 | |
3a5c359a AK |
1388 | for (;;) { |
1389 | /* | |
1390 | * We do the initial early heuristics without holding | |
1391 | * any task-queue locks at all. We'll only try to get | |
1392 | * the runqueue lock when things look like they will | |
1393 | * work out! | |
1394 | */ | |
1395 | rq = task_rq(p); | |
fa490cfd | 1396 | |
3a5c359a AK |
1397 | /* |
1398 | * If the task is actively running on another CPU | |
1399 | * still, just relax and busy-wait without holding | |
1400 | * any locks. | |
1401 | * | |
1402 | * NOTE! Since we don't hold any locks, it's not | |
1403 | * even sure that "rq" stays as the right runqueue! | |
1404 | * But we don't care, since "task_running()" will | |
1405 | * return false if the runqueue has changed and p | |
1406 | * is actually now running somewhere else! | |
1407 | */ | |
85ba2d86 RM |
1408 | while (task_running(rq, p)) { |
1409 | if (match_state && unlikely(p->state != match_state)) | |
1410 | return 0; | |
3a5c359a | 1411 | cpu_relax(); |
85ba2d86 | 1412 | } |
fa490cfd | 1413 | |
3a5c359a AK |
1414 | /* |
1415 | * Ok, time to look more closely! We need the rq | |
1416 | * lock now, to be *sure*. If we're wrong, we'll | |
1417 | * just go back and repeat. | |
1418 | */ | |
eb580751 | 1419 | rq = task_rq_lock(p, &rf); |
27a9da65 | 1420 | trace_sched_wait_task(p); |
3a5c359a | 1421 | running = task_running(rq, p); |
da0c1e65 | 1422 | queued = task_on_rq_queued(p); |
85ba2d86 | 1423 | ncsw = 0; |
f31e11d8 | 1424 | if (!match_state || p->state == match_state) |
93dcf55f | 1425 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
eb580751 | 1426 | task_rq_unlock(rq, p, &rf); |
fa490cfd | 1427 | |
85ba2d86 RM |
1428 | /* |
1429 | * If it changed from the expected state, bail out now. | |
1430 | */ | |
1431 | if (unlikely(!ncsw)) | |
1432 | break; | |
1433 | ||
3a5c359a AK |
1434 | /* |
1435 | * Was it really running after all now that we | |
1436 | * checked with the proper locks actually held? | |
1437 | * | |
1438 | * Oops. Go back and try again.. | |
1439 | */ | |
1440 | if (unlikely(running)) { | |
1441 | cpu_relax(); | |
1442 | continue; | |
1443 | } | |
fa490cfd | 1444 | |
3a5c359a AK |
1445 | /* |
1446 | * It's not enough that it's not actively running, | |
1447 | * it must be off the runqueue _entirely_, and not | |
1448 | * preempted! | |
1449 | * | |
80dd99b3 | 1450 | * So if it was still runnable (but just not actively |
3a5c359a AK |
1451 | * running right now), it's preempted, and we should |
1452 | * yield - it could be a while. | |
1453 | */ | |
da0c1e65 | 1454 | if (unlikely(queued)) { |
8eb90c30 TG |
1455 | ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); |
1456 | ||
1457 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1458 | schedule_hrtimeout(&to, HRTIMER_MODE_REL); | |
3a5c359a AK |
1459 | continue; |
1460 | } | |
fa490cfd | 1461 | |
3a5c359a AK |
1462 | /* |
1463 | * Ahh, all good. It wasn't running, and it wasn't | |
1464 | * runnable, which means that it will never become | |
1465 | * running in the future either. We're all done! | |
1466 | */ | |
1467 | break; | |
1468 | } | |
85ba2d86 RM |
1469 | |
1470 | return ncsw; | |
1da177e4 LT |
1471 | } |
1472 | ||
1473 | /*** | |
1474 | * kick_process - kick a running thread to enter/exit the kernel | |
1475 | * @p: the to-be-kicked thread | |
1476 | * | |
1477 | * Cause a process which is running on another CPU to enter | |
1478 | * kernel-mode, without any delay. (to get signals handled.) | |
1479 | * | |
25985edc | 1480 | * NOTE: this function doesn't have to take the runqueue lock, |
1da177e4 LT |
1481 | * because all it wants to ensure is that the remote task enters |
1482 | * the kernel. If the IPI races and the task has been migrated | |
1483 | * to another CPU then no harm is done and the purpose has been | |
1484 | * achieved as well. | |
1485 | */ | |
36c8b586 | 1486 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1487 | { |
1488 | int cpu; | |
1489 | ||
1490 | preempt_disable(); | |
1491 | cpu = task_cpu(p); | |
1492 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1493 | smp_send_reschedule(cpu); | |
1494 | preempt_enable(); | |
1495 | } | |
b43e3521 | 1496 | EXPORT_SYMBOL_GPL(kick_process); |
1da177e4 | 1497 | |
30da688e | 1498 | /* |
013fdb80 | 1499 | * ->cpus_allowed is protected by both rq->lock and p->pi_lock |
e9d867a6 PZI |
1500 | * |
1501 | * A few notes on cpu_active vs cpu_online: | |
1502 | * | |
1503 | * - cpu_active must be a subset of cpu_online | |
1504 | * | |
1505 | * - on cpu-up we allow per-cpu kthreads on the online && !active cpu, | |
1506 | * see __set_cpus_allowed_ptr(). At this point the newly online | |
1507 | * cpu isn't yet part of the sched domains, and balancing will not | |
1508 | * see it. | |
1509 | * | |
1510 | * - on cpu-down we clear cpu_active() to mask the sched domains and | |
1511 | * avoid the load balancer to place new tasks on the to be removed | |
1512 | * cpu. Existing tasks will remain running there and will be taken | |
1513 | * off. | |
1514 | * | |
1515 | * This means that fallback selection must not select !active CPUs. | |
1516 | * And can assume that any active CPU must be online. Conversely | |
1517 | * select_task_rq() below may allow selection of !active CPUs in order | |
1518 | * to satisfy the above rules. | |
30da688e | 1519 | */ |
5da9a0fb PZ |
1520 | static int select_fallback_rq(int cpu, struct task_struct *p) |
1521 | { | |
aa00d89c TC |
1522 | int nid = cpu_to_node(cpu); |
1523 | const struct cpumask *nodemask = NULL; | |
2baab4e9 PZ |
1524 | enum { cpuset, possible, fail } state = cpuset; |
1525 | int dest_cpu; | |
5da9a0fb | 1526 | |
aa00d89c TC |
1527 | /* |
1528 | * If the node that the cpu is on has been offlined, cpu_to_node() | |
1529 | * will return -1. There is no cpu on the node, and we should | |
1530 | * select the cpu on the other node. | |
1531 | */ | |
1532 | if (nid != -1) { | |
1533 | nodemask = cpumask_of_node(nid); | |
1534 | ||
1535 | /* Look for allowed, online CPU in same node. */ | |
1536 | for_each_cpu(dest_cpu, nodemask) { | |
aa00d89c TC |
1537 | if (!cpu_active(dest_cpu)) |
1538 | continue; | |
1539 | if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) | |
1540 | return dest_cpu; | |
1541 | } | |
2baab4e9 | 1542 | } |
5da9a0fb | 1543 | |
2baab4e9 PZ |
1544 | for (;;) { |
1545 | /* Any allowed, online CPU? */ | |
e3831edd | 1546 | for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { |
feb245e3 TH |
1547 | if (!(p->flags & PF_KTHREAD) && !cpu_active(dest_cpu)) |
1548 | continue; | |
1549 | if (!cpu_online(dest_cpu)) | |
2baab4e9 PZ |
1550 | continue; |
1551 | goto out; | |
1552 | } | |
5da9a0fb | 1553 | |
e73e85f0 | 1554 | /* No more Mr. Nice Guy. */ |
2baab4e9 PZ |
1555 | switch (state) { |
1556 | case cpuset: | |
e73e85f0 ON |
1557 | if (IS_ENABLED(CONFIG_CPUSETS)) { |
1558 | cpuset_cpus_allowed_fallback(p); | |
1559 | state = possible; | |
1560 | break; | |
1561 | } | |
1562 | /* fall-through */ | |
2baab4e9 PZ |
1563 | case possible: |
1564 | do_set_cpus_allowed(p, cpu_possible_mask); | |
1565 | state = fail; | |
1566 | break; | |
1567 | ||
1568 | case fail: | |
1569 | BUG(); | |
1570 | break; | |
1571 | } | |
1572 | } | |
1573 | ||
1574 | out: | |
1575 | if (state != cpuset) { | |
1576 | /* | |
1577 | * Don't tell them about moving exiting tasks or | |
1578 | * kernel threads (both mm NULL), since they never | |
1579 | * leave kernel. | |
1580 | */ | |
1581 | if (p->mm && printk_ratelimit()) { | |
aac74dc4 | 1582 | printk_deferred("process %d (%s) no longer affine to cpu%d\n", |
2baab4e9 PZ |
1583 | task_pid_nr(p), p->comm, cpu); |
1584 | } | |
5da9a0fb PZ |
1585 | } |
1586 | ||
1587 | return dest_cpu; | |
1588 | } | |
1589 | ||
e2912009 | 1590 | /* |
013fdb80 | 1591 | * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. |
e2912009 | 1592 | */ |
970b13ba | 1593 | static inline |
ac66f547 | 1594 | int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) |
970b13ba | 1595 | { |
cbce1a68 PZ |
1596 | lockdep_assert_held(&p->pi_lock); |
1597 | ||
50605ffb | 1598 | if (tsk_nr_cpus_allowed(p) > 1) |
6c1d9410 | 1599 | cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); |
e9d867a6 PZI |
1600 | else |
1601 | cpu = cpumask_any(tsk_cpus_allowed(p)); | |
e2912009 PZ |
1602 | |
1603 | /* | |
1604 | * In order not to call set_task_cpu() on a blocking task we need | |
1605 | * to rely on ttwu() to place the task on a valid ->cpus_allowed | |
1606 | * cpu. | |
1607 | * | |
1608 | * Since this is common to all placement strategies, this lives here. | |
1609 | * | |
1610 | * [ this allows ->select_task() to simply return task_cpu(p) and | |
1611 | * not worry about this generic constraint ] | |
1612 | */ | |
fa17b507 | 1613 | if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || |
70f11205 | 1614 | !cpu_online(cpu))) |
5da9a0fb | 1615 | cpu = select_fallback_rq(task_cpu(p), p); |
e2912009 PZ |
1616 | |
1617 | return cpu; | |
970b13ba | 1618 | } |
09a40af5 MG |
1619 | |
1620 | static void update_avg(u64 *avg, u64 sample) | |
1621 | { | |
1622 | s64 diff = sample - *avg; | |
1623 | *avg += diff >> 3; | |
1624 | } | |
25834c73 PZ |
1625 | |
1626 | #else | |
1627 | ||
1628 | static inline int __set_cpus_allowed_ptr(struct task_struct *p, | |
1629 | const struct cpumask *new_mask, bool check) | |
1630 | { | |
1631 | return set_cpus_allowed_ptr(p, new_mask); | |
1632 | } | |
1633 | ||
5cc389bc | 1634 | #endif /* CONFIG_SMP */ |
970b13ba | 1635 | |
d7c01d27 | 1636 | static void |
b84cb5df | 1637 | ttwu_stat(struct task_struct *p, int cpu, int wake_flags) |
9ed3811a | 1638 | { |
4fa8d299 | 1639 | struct rq *rq; |
b84cb5df | 1640 | |
4fa8d299 JP |
1641 | if (!schedstat_enabled()) |
1642 | return; | |
1643 | ||
1644 | rq = this_rq(); | |
d7c01d27 | 1645 | |
4fa8d299 JP |
1646 | #ifdef CONFIG_SMP |
1647 | if (cpu == rq->cpu) { | |
ae92882e JP |
1648 | schedstat_inc(rq->ttwu_local); |
1649 | schedstat_inc(p->se.statistics.nr_wakeups_local); | |
d7c01d27 PZ |
1650 | } else { |
1651 | struct sched_domain *sd; | |
1652 | ||
ae92882e | 1653 | schedstat_inc(p->se.statistics.nr_wakeups_remote); |
057f3fad | 1654 | rcu_read_lock(); |
4fa8d299 | 1655 | for_each_domain(rq->cpu, sd) { |
d7c01d27 | 1656 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
ae92882e | 1657 | schedstat_inc(sd->ttwu_wake_remote); |
d7c01d27 PZ |
1658 | break; |
1659 | } | |
1660 | } | |
057f3fad | 1661 | rcu_read_unlock(); |
d7c01d27 | 1662 | } |
f339b9dc PZ |
1663 | |
1664 | if (wake_flags & WF_MIGRATED) | |
ae92882e | 1665 | schedstat_inc(p->se.statistics.nr_wakeups_migrate); |
d7c01d27 PZ |
1666 | #endif /* CONFIG_SMP */ |
1667 | ||
ae92882e JP |
1668 | schedstat_inc(rq->ttwu_count); |
1669 | schedstat_inc(p->se.statistics.nr_wakeups); | |
d7c01d27 PZ |
1670 | |
1671 | if (wake_flags & WF_SYNC) | |
ae92882e | 1672 | schedstat_inc(p->se.statistics.nr_wakeups_sync); |
d7c01d27 PZ |
1673 | } |
1674 | ||
1de64443 | 1675 | static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) |
d7c01d27 | 1676 | { |
9ed3811a | 1677 | activate_task(rq, p, en_flags); |
da0c1e65 | 1678 | p->on_rq = TASK_ON_RQ_QUEUED; |
c2f7115e PZ |
1679 | |
1680 | /* if a worker is waking up, notify workqueue */ | |
1681 | if (p->flags & PF_WQ_WORKER) | |
1682 | wq_worker_waking_up(p, cpu_of(rq)); | |
9ed3811a TH |
1683 | } |
1684 | ||
23f41eeb PZ |
1685 | /* |
1686 | * Mark the task runnable and perform wakeup-preemption. | |
1687 | */ | |
e7904a28 PZ |
1688 | static void ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags, |
1689 | struct pin_cookie cookie) | |
9ed3811a | 1690 | { |
9ed3811a | 1691 | check_preempt_curr(rq, p, wake_flags); |
9ed3811a | 1692 | p->state = TASK_RUNNING; |
fbd705a0 PZ |
1693 | trace_sched_wakeup(p); |
1694 | ||
9ed3811a | 1695 | #ifdef CONFIG_SMP |
4c9a4bc8 PZ |
1696 | if (p->sched_class->task_woken) { |
1697 | /* | |
cbce1a68 PZ |
1698 | * Our task @p is fully woken up and running; so its safe to |
1699 | * drop the rq->lock, hereafter rq is only used for statistics. | |
4c9a4bc8 | 1700 | */ |
e7904a28 | 1701 | lockdep_unpin_lock(&rq->lock, cookie); |
9ed3811a | 1702 | p->sched_class->task_woken(rq, p); |
e7904a28 | 1703 | lockdep_repin_lock(&rq->lock, cookie); |
4c9a4bc8 | 1704 | } |
9ed3811a | 1705 | |
e69c6341 | 1706 | if (rq->idle_stamp) { |
78becc27 | 1707 | u64 delta = rq_clock(rq) - rq->idle_stamp; |
9bd721c5 | 1708 | u64 max = 2*rq->max_idle_balance_cost; |
9ed3811a | 1709 | |
abfafa54 JL |
1710 | update_avg(&rq->avg_idle, delta); |
1711 | ||
1712 | if (rq->avg_idle > max) | |
9ed3811a | 1713 | rq->avg_idle = max; |
abfafa54 | 1714 | |
9ed3811a TH |
1715 | rq->idle_stamp = 0; |
1716 | } | |
1717 | #endif | |
1718 | } | |
1719 | ||
c05fbafb | 1720 | static void |
e7904a28 PZ |
1721 | ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags, |
1722 | struct pin_cookie cookie) | |
c05fbafb | 1723 | { |
b5179ac7 PZ |
1724 | int en_flags = ENQUEUE_WAKEUP; |
1725 | ||
cbce1a68 PZ |
1726 | lockdep_assert_held(&rq->lock); |
1727 | ||
c05fbafb PZ |
1728 | #ifdef CONFIG_SMP |
1729 | if (p->sched_contributes_to_load) | |
1730 | rq->nr_uninterruptible--; | |
b5179ac7 | 1731 | |
b5179ac7 | 1732 | if (wake_flags & WF_MIGRATED) |
59efa0ba | 1733 | en_flags |= ENQUEUE_MIGRATED; |
c05fbafb PZ |
1734 | #endif |
1735 | ||
b5179ac7 | 1736 | ttwu_activate(rq, p, en_flags); |
e7904a28 | 1737 | ttwu_do_wakeup(rq, p, wake_flags, cookie); |
c05fbafb PZ |
1738 | } |
1739 | ||
1740 | /* | |
1741 | * Called in case the task @p isn't fully descheduled from its runqueue, | |
1742 | * in this case we must do a remote wakeup. Its a 'light' wakeup though, | |
1743 | * since all we need to do is flip p->state to TASK_RUNNING, since | |
1744 | * the task is still ->on_rq. | |
1745 | */ | |
1746 | static int ttwu_remote(struct task_struct *p, int wake_flags) | |
1747 | { | |
eb580751 | 1748 | struct rq_flags rf; |
c05fbafb PZ |
1749 | struct rq *rq; |
1750 | int ret = 0; | |
1751 | ||
eb580751 | 1752 | rq = __task_rq_lock(p, &rf); |
da0c1e65 | 1753 | if (task_on_rq_queued(p)) { |
1ad4ec0d FW |
1754 | /* check_preempt_curr() may use rq clock */ |
1755 | update_rq_clock(rq); | |
e7904a28 | 1756 | ttwu_do_wakeup(rq, p, wake_flags, rf.cookie); |
c05fbafb PZ |
1757 | ret = 1; |
1758 | } | |
eb580751 | 1759 | __task_rq_unlock(rq, &rf); |
c05fbafb PZ |
1760 | |
1761 | return ret; | |
1762 | } | |
1763 | ||
317f3941 | 1764 | #ifdef CONFIG_SMP |
e3baac47 | 1765 | void sched_ttwu_pending(void) |
317f3941 PZ |
1766 | { |
1767 | struct rq *rq = this_rq(); | |
fa14ff4a | 1768 | struct llist_node *llist = llist_del_all(&rq->wake_list); |
e7904a28 | 1769 | struct pin_cookie cookie; |
fa14ff4a | 1770 | struct task_struct *p; |
e3baac47 | 1771 | unsigned long flags; |
317f3941 | 1772 | |
e3baac47 PZ |
1773 | if (!llist) |
1774 | return; | |
1775 | ||
1776 | raw_spin_lock_irqsave(&rq->lock, flags); | |
e7904a28 | 1777 | cookie = lockdep_pin_lock(&rq->lock); |
317f3941 | 1778 | |
fa14ff4a | 1779 | while (llist) { |
b7e7ade3 PZ |
1780 | int wake_flags = 0; |
1781 | ||
fa14ff4a PZ |
1782 | p = llist_entry(llist, struct task_struct, wake_entry); |
1783 | llist = llist_next(llist); | |
b7e7ade3 PZ |
1784 | |
1785 | if (p->sched_remote_wakeup) | |
1786 | wake_flags = WF_MIGRATED; | |
1787 | ||
1788 | ttwu_do_activate(rq, p, wake_flags, cookie); | |
317f3941 PZ |
1789 | } |
1790 | ||
e7904a28 | 1791 | lockdep_unpin_lock(&rq->lock, cookie); |
e3baac47 | 1792 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
317f3941 PZ |
1793 | } |
1794 | ||
1795 | void scheduler_ipi(void) | |
1796 | { | |
f27dde8d PZ |
1797 | /* |
1798 | * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting | |
1799 | * TIF_NEED_RESCHED remotely (for the first time) will also send | |
1800 | * this IPI. | |
1801 | */ | |
8cb75e0c | 1802 | preempt_fold_need_resched(); |
f27dde8d | 1803 | |
fd2ac4f4 | 1804 | if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) |
c5d753a5 PZ |
1805 | return; |
1806 | ||
1807 | /* | |
1808 | * Not all reschedule IPI handlers call irq_enter/irq_exit, since | |
1809 | * traditionally all their work was done from the interrupt return | |
1810 | * path. Now that we actually do some work, we need to make sure | |
1811 | * we do call them. | |
1812 | * | |
1813 | * Some archs already do call them, luckily irq_enter/exit nest | |
1814 | * properly. | |
1815 | * | |
1816 | * Arguably we should visit all archs and update all handlers, | |
1817 | * however a fair share of IPIs are still resched only so this would | |
1818 | * somewhat pessimize the simple resched case. | |
1819 | */ | |
1820 | irq_enter(); | |
fa14ff4a | 1821 | sched_ttwu_pending(); |
ca38062e SS |
1822 | |
1823 | /* | |
1824 | * Check if someone kicked us for doing the nohz idle load balance. | |
1825 | */ | |
873b4c65 | 1826 | if (unlikely(got_nohz_idle_kick())) { |
6eb57e0d | 1827 | this_rq()->idle_balance = 1; |
ca38062e | 1828 | raise_softirq_irqoff(SCHED_SOFTIRQ); |
6eb57e0d | 1829 | } |
c5d753a5 | 1830 | irq_exit(); |
317f3941 PZ |
1831 | } |
1832 | ||
b7e7ade3 | 1833 | static void ttwu_queue_remote(struct task_struct *p, int cpu, int wake_flags) |
317f3941 | 1834 | { |
e3baac47 PZ |
1835 | struct rq *rq = cpu_rq(cpu); |
1836 | ||
b7e7ade3 PZ |
1837 | p->sched_remote_wakeup = !!(wake_flags & WF_MIGRATED); |
1838 | ||
e3baac47 PZ |
1839 | if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { |
1840 | if (!set_nr_if_polling(rq->idle)) | |
1841 | smp_send_reschedule(cpu); | |
1842 | else | |
1843 | trace_sched_wake_idle_without_ipi(cpu); | |
1844 | } | |
317f3941 | 1845 | } |
d6aa8f85 | 1846 | |
f6be8af1 CL |
1847 | void wake_up_if_idle(int cpu) |
1848 | { | |
1849 | struct rq *rq = cpu_rq(cpu); | |
1850 | unsigned long flags; | |
1851 | ||
fd7de1e8 AL |
1852 | rcu_read_lock(); |
1853 | ||
1854 | if (!is_idle_task(rcu_dereference(rq->curr))) | |
1855 | goto out; | |
f6be8af1 CL |
1856 | |
1857 | if (set_nr_if_polling(rq->idle)) { | |
1858 | trace_sched_wake_idle_without_ipi(cpu); | |
1859 | } else { | |
1860 | raw_spin_lock_irqsave(&rq->lock, flags); | |
1861 | if (is_idle_task(rq->curr)) | |
1862 | smp_send_reschedule(cpu); | |
1863 | /* Else cpu is not in idle, do nothing here */ | |
1864 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
1865 | } | |
fd7de1e8 AL |
1866 | |
1867 | out: | |
1868 | rcu_read_unlock(); | |
f6be8af1 CL |
1869 | } |
1870 | ||
39be3501 | 1871 | bool cpus_share_cache(int this_cpu, int that_cpu) |
518cd623 PZ |
1872 | { |
1873 | return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); | |
1874 | } | |
d6aa8f85 | 1875 | #endif /* CONFIG_SMP */ |
317f3941 | 1876 | |
b5179ac7 | 1877 | static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) |
c05fbafb PZ |
1878 | { |
1879 | struct rq *rq = cpu_rq(cpu); | |
e7904a28 | 1880 | struct pin_cookie cookie; |
c05fbafb | 1881 | |
17d9f311 | 1882 | #if defined(CONFIG_SMP) |
39be3501 | 1883 | if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { |
f01114cb | 1884 | sched_clock_cpu(cpu); /* sync clocks x-cpu */ |
b7e7ade3 | 1885 | ttwu_queue_remote(p, cpu, wake_flags); |
317f3941 PZ |
1886 | return; |
1887 | } | |
1888 | #endif | |
1889 | ||
c05fbafb | 1890 | raw_spin_lock(&rq->lock); |
e7904a28 | 1891 | cookie = lockdep_pin_lock(&rq->lock); |
b5179ac7 | 1892 | ttwu_do_activate(rq, p, wake_flags, cookie); |
e7904a28 | 1893 | lockdep_unpin_lock(&rq->lock, cookie); |
c05fbafb | 1894 | raw_spin_unlock(&rq->lock); |
9ed3811a TH |
1895 | } |
1896 | ||
8643cda5 PZ |
1897 | /* |
1898 | * Notes on Program-Order guarantees on SMP systems. | |
1899 | * | |
1900 | * MIGRATION | |
1901 | * | |
1902 | * The basic program-order guarantee on SMP systems is that when a task [t] | |
1903 | * migrates, all its activity on its old cpu [c0] happens-before any subsequent | |
1904 | * execution on its new cpu [c1]. | |
1905 | * | |
1906 | * For migration (of runnable tasks) this is provided by the following means: | |
1907 | * | |
1908 | * A) UNLOCK of the rq(c0)->lock scheduling out task t | |
1909 | * B) migration for t is required to synchronize *both* rq(c0)->lock and | |
1910 | * rq(c1)->lock (if not at the same time, then in that order). | |
1911 | * C) LOCK of the rq(c1)->lock scheduling in task | |
1912 | * | |
1913 | * Transitivity guarantees that B happens after A and C after B. | |
1914 | * Note: we only require RCpc transitivity. | |
1915 | * Note: the cpu doing B need not be c0 or c1 | |
1916 | * | |
1917 | * Example: | |
1918 | * | |
1919 | * CPU0 CPU1 CPU2 | |
1920 | * | |
1921 | * LOCK rq(0)->lock | |
1922 | * sched-out X | |
1923 | * sched-in Y | |
1924 | * UNLOCK rq(0)->lock | |
1925 | * | |
1926 | * LOCK rq(0)->lock // orders against CPU0 | |
1927 | * dequeue X | |
1928 | * UNLOCK rq(0)->lock | |
1929 | * | |
1930 | * LOCK rq(1)->lock | |
1931 | * enqueue X | |
1932 | * UNLOCK rq(1)->lock | |
1933 | * | |
1934 | * LOCK rq(1)->lock // orders against CPU2 | |
1935 | * sched-out Z | |
1936 | * sched-in X | |
1937 | * UNLOCK rq(1)->lock | |
1938 | * | |
1939 | * | |
1940 | * BLOCKING -- aka. SLEEP + WAKEUP | |
1941 | * | |
1942 | * For blocking we (obviously) need to provide the same guarantee as for | |
1943 | * migration. However the means are completely different as there is no lock | |
1944 | * chain to provide order. Instead we do: | |
1945 | * | |
1946 | * 1) smp_store_release(X->on_cpu, 0) | |
1f03e8d2 | 1947 | * 2) smp_cond_load_acquire(!X->on_cpu) |
8643cda5 PZ |
1948 | * |
1949 | * Example: | |
1950 | * | |
1951 | * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule) | |
1952 | * | |
1953 | * LOCK rq(0)->lock LOCK X->pi_lock | |
1954 | * dequeue X | |
1955 | * sched-out X | |
1956 | * smp_store_release(X->on_cpu, 0); | |
1957 | * | |
1f03e8d2 | 1958 | * smp_cond_load_acquire(&X->on_cpu, !VAL); |
8643cda5 PZ |
1959 | * X->state = WAKING |
1960 | * set_task_cpu(X,2) | |
1961 | * | |
1962 | * LOCK rq(2)->lock | |
1963 | * enqueue X | |
1964 | * X->state = RUNNING | |
1965 | * UNLOCK rq(2)->lock | |
1966 | * | |
1967 | * LOCK rq(2)->lock // orders against CPU1 | |
1968 | * sched-out Z | |
1969 | * sched-in X | |
1970 | * UNLOCK rq(2)->lock | |
1971 | * | |
1972 | * UNLOCK X->pi_lock | |
1973 | * UNLOCK rq(0)->lock | |
1974 | * | |
1975 | * | |
1976 | * However; for wakeups there is a second guarantee we must provide, namely we | |
1977 | * must observe the state that lead to our wakeup. That is, not only must our | |
1978 | * task observe its own prior state, it must also observe the stores prior to | |
1979 | * its wakeup. | |
1980 | * | |
1981 | * This means that any means of doing remote wakeups must order the CPU doing | |
1982 | * the wakeup against the CPU the task is going to end up running on. This, | |
1983 | * however, is already required for the regular Program-Order guarantee above, | |
1f03e8d2 | 1984 | * since the waking CPU is the one issueing the ACQUIRE (smp_cond_load_acquire). |
8643cda5 PZ |
1985 | * |
1986 | */ | |
1987 | ||
9ed3811a | 1988 | /** |
1da177e4 | 1989 | * try_to_wake_up - wake up a thread |
9ed3811a | 1990 | * @p: the thread to be awakened |
1da177e4 | 1991 | * @state: the mask of task states that can be woken |
9ed3811a | 1992 | * @wake_flags: wake modifier flags (WF_*) |
1da177e4 LT |
1993 | * |
1994 | * Put it on the run-queue if it's not already there. The "current" | |
1995 | * thread is always on the run-queue (except when the actual | |
1996 | * re-schedule is in progress), and as such you're allowed to do | |
1997 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
1998 | * runnable without the overhead of this. | |
1999 | * | |
e69f6186 | 2000 | * Return: %true if @p was woken up, %false if it was already running. |
9ed3811a | 2001 | * or @state didn't match @p's state. |
1da177e4 | 2002 | */ |
e4a52bcb PZ |
2003 | static int |
2004 | try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) | |
1da177e4 | 2005 | { |
1da177e4 | 2006 | unsigned long flags; |
c05fbafb | 2007 | int cpu, success = 0; |
2398f2c6 | 2008 | |
e0acd0a6 ON |
2009 | /* |
2010 | * If we are going to wake up a thread waiting for CONDITION we | |
2011 | * need to ensure that CONDITION=1 done by the caller can not be | |
2012 | * reordered with p->state check below. This pairs with mb() in | |
2013 | * set_current_state() the waiting thread does. | |
2014 | */ | |
2015 | smp_mb__before_spinlock(); | |
013fdb80 | 2016 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
e9c84311 | 2017 | if (!(p->state & state)) |
1da177e4 LT |
2018 | goto out; |
2019 | ||
fbd705a0 PZ |
2020 | trace_sched_waking(p); |
2021 | ||
c05fbafb | 2022 | success = 1; /* we're going to change ->state */ |
1da177e4 | 2023 | cpu = task_cpu(p); |
1da177e4 | 2024 | |
135e8c92 BS |
2025 | /* |
2026 | * Ensure we load p->on_rq _after_ p->state, otherwise it would | |
2027 | * be possible to, falsely, observe p->on_rq == 0 and get stuck | |
2028 | * in smp_cond_load_acquire() below. | |
2029 | * | |
2030 | * sched_ttwu_pending() try_to_wake_up() | |
2031 | * [S] p->on_rq = 1; [L] P->state | |
2032 | * UNLOCK rq->lock -----. | |
2033 | * \ | |
2034 | * +--- RMB | |
2035 | * schedule() / | |
2036 | * LOCK rq->lock -----' | |
2037 | * UNLOCK rq->lock | |
2038 | * | |
2039 | * [task p] | |
2040 | * [S] p->state = UNINTERRUPTIBLE [L] p->on_rq | |
2041 | * | |
2042 | * Pairs with the UNLOCK+LOCK on rq->lock from the | |
2043 | * last wakeup of our task and the schedule that got our task | |
2044 | * current. | |
2045 | */ | |
2046 | smp_rmb(); | |
c05fbafb PZ |
2047 | if (p->on_rq && ttwu_remote(p, wake_flags)) |
2048 | goto stat; | |
1da177e4 | 2049 | |
1da177e4 | 2050 | #ifdef CONFIG_SMP |
ecf7d01c PZ |
2051 | /* |
2052 | * Ensure we load p->on_cpu _after_ p->on_rq, otherwise it would be | |
2053 | * possible to, falsely, observe p->on_cpu == 0. | |
2054 | * | |
2055 | * One must be running (->on_cpu == 1) in order to remove oneself | |
2056 | * from the runqueue. | |
2057 | * | |
2058 | * [S] ->on_cpu = 1; [L] ->on_rq | |
2059 | * UNLOCK rq->lock | |
2060 | * RMB | |
2061 | * LOCK rq->lock | |
2062 | * [S] ->on_rq = 0; [L] ->on_cpu | |
2063 | * | |
2064 | * Pairs with the full barrier implied in the UNLOCK+LOCK on rq->lock | |
2065 | * from the consecutive calls to schedule(); the first switching to our | |
2066 | * task, the second putting it to sleep. | |
2067 | */ | |
2068 | smp_rmb(); | |
2069 | ||
e9c84311 | 2070 | /* |
c05fbafb PZ |
2071 | * If the owning (remote) cpu is still in the middle of schedule() with |
2072 | * this task as prev, wait until its done referencing the task. | |
b75a2253 PZ |
2073 | * |
2074 | * Pairs with the smp_store_release() in finish_lock_switch(). | |
2075 | * | |
2076 | * This ensures that tasks getting woken will be fully ordered against | |
2077 | * their previous state and preserve Program Order. | |
0970d299 | 2078 | */ |
1f03e8d2 | 2079 | smp_cond_load_acquire(&p->on_cpu, !VAL); |
1da177e4 | 2080 | |
a8e4f2ea | 2081 | p->sched_contributes_to_load = !!task_contributes_to_load(p); |
e9c84311 | 2082 | p->state = TASK_WAKING; |
e7693a36 | 2083 | |
ac66f547 | 2084 | cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); |
f339b9dc PZ |
2085 | if (task_cpu(p) != cpu) { |
2086 | wake_flags |= WF_MIGRATED; | |
e4a52bcb | 2087 | set_task_cpu(p, cpu); |
f339b9dc | 2088 | } |
1da177e4 | 2089 | #endif /* CONFIG_SMP */ |
1da177e4 | 2090 | |
b5179ac7 | 2091 | ttwu_queue(p, cpu, wake_flags); |
c05fbafb | 2092 | stat: |
4fa8d299 | 2093 | ttwu_stat(p, cpu, wake_flags); |
1da177e4 | 2094 | out: |
013fdb80 | 2095 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
2096 | |
2097 | return success; | |
2098 | } | |
2099 | ||
21aa9af0 TH |
2100 | /** |
2101 | * try_to_wake_up_local - try to wake up a local task with rq lock held | |
2102 | * @p: the thread to be awakened | |
9279e0d2 | 2103 | * @cookie: context's cookie for pinning |
21aa9af0 | 2104 | * |
2acca55e | 2105 | * Put @p on the run-queue if it's not already there. The caller must |
21aa9af0 | 2106 | * ensure that this_rq() is locked, @p is bound to this_rq() and not |
2acca55e | 2107 | * the current task. |
21aa9af0 | 2108 | */ |
e7904a28 | 2109 | static void try_to_wake_up_local(struct task_struct *p, struct pin_cookie cookie) |
21aa9af0 TH |
2110 | { |
2111 | struct rq *rq = task_rq(p); | |
21aa9af0 | 2112 | |
383efcd0 TH |
2113 | if (WARN_ON_ONCE(rq != this_rq()) || |
2114 | WARN_ON_ONCE(p == current)) | |
2115 | return; | |
2116 | ||
21aa9af0 TH |
2117 | lockdep_assert_held(&rq->lock); |
2118 | ||
2acca55e | 2119 | if (!raw_spin_trylock(&p->pi_lock)) { |
cbce1a68 PZ |
2120 | /* |
2121 | * This is OK, because current is on_cpu, which avoids it being | |
2122 | * picked for load-balance and preemption/IRQs are still | |
2123 | * disabled avoiding further scheduler activity on it and we've | |
2124 | * not yet picked a replacement task. | |
2125 | */ | |
e7904a28 | 2126 | lockdep_unpin_lock(&rq->lock, cookie); |
2acca55e PZ |
2127 | raw_spin_unlock(&rq->lock); |
2128 | raw_spin_lock(&p->pi_lock); | |
2129 | raw_spin_lock(&rq->lock); | |
e7904a28 | 2130 | lockdep_repin_lock(&rq->lock, cookie); |
2acca55e PZ |
2131 | } |
2132 | ||
21aa9af0 | 2133 | if (!(p->state & TASK_NORMAL)) |
2acca55e | 2134 | goto out; |
21aa9af0 | 2135 | |
fbd705a0 PZ |
2136 | trace_sched_waking(p); |
2137 | ||
da0c1e65 | 2138 | if (!task_on_rq_queued(p)) |
d7c01d27 PZ |
2139 | ttwu_activate(rq, p, ENQUEUE_WAKEUP); |
2140 | ||
e7904a28 | 2141 | ttwu_do_wakeup(rq, p, 0, cookie); |
4fa8d299 | 2142 | ttwu_stat(p, smp_processor_id(), 0); |
2acca55e PZ |
2143 | out: |
2144 | raw_spin_unlock(&p->pi_lock); | |
21aa9af0 TH |
2145 | } |
2146 | ||
50fa610a DH |
2147 | /** |
2148 | * wake_up_process - Wake up a specific process | |
2149 | * @p: The process to be woken up. | |
2150 | * | |
2151 | * Attempt to wake up the nominated process and move it to the set of runnable | |
e69f6186 YB |
2152 | * processes. |
2153 | * | |
2154 | * Return: 1 if the process was woken up, 0 if it was already running. | |
50fa610a DH |
2155 | * |
2156 | * It may be assumed that this function implies a write memory barrier before | |
2157 | * changing the task state if and only if any tasks are woken up. | |
2158 | */ | |
7ad5b3a5 | 2159 | int wake_up_process(struct task_struct *p) |
1da177e4 | 2160 | { |
9067ac85 | 2161 | return try_to_wake_up(p, TASK_NORMAL, 0); |
1da177e4 | 2162 | } |
1da177e4 LT |
2163 | EXPORT_SYMBOL(wake_up_process); |
2164 | ||
7ad5b3a5 | 2165 | int wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
2166 | { |
2167 | return try_to_wake_up(p, state, 0); | |
2168 | } | |
2169 | ||
a5e7be3b JL |
2170 | /* |
2171 | * This function clears the sched_dl_entity static params. | |
2172 | */ | |
2173 | void __dl_clear_params(struct task_struct *p) | |
2174 | { | |
2175 | struct sched_dl_entity *dl_se = &p->dl; | |
2176 | ||
2177 | dl_se->dl_runtime = 0; | |
2178 | dl_se->dl_deadline = 0; | |
2179 | dl_se->dl_period = 0; | |
2180 | dl_se->flags = 0; | |
2181 | dl_se->dl_bw = 0; | |
40767b0d PZ |
2182 | |
2183 | dl_se->dl_throttled = 0; | |
40767b0d | 2184 | dl_se->dl_yielded = 0; |
a5e7be3b JL |
2185 | } |
2186 | ||
1da177e4 LT |
2187 | /* |
2188 | * Perform scheduler related setup for a newly forked process p. | |
2189 | * p is forked by current. | |
dd41f596 IM |
2190 | * |
2191 | * __sched_fork() is basic setup used by init_idle() too: | |
2192 | */ | |
5e1576ed | 2193 | static void __sched_fork(unsigned long clone_flags, struct task_struct *p) |
dd41f596 | 2194 | { |
fd2f4419 PZ |
2195 | p->on_rq = 0; |
2196 | ||
2197 | p->se.on_rq = 0; | |
dd41f596 IM |
2198 | p->se.exec_start = 0; |
2199 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 2200 | p->se.prev_sum_exec_runtime = 0; |
6c594c21 | 2201 | p->se.nr_migrations = 0; |
da7a735e | 2202 | p->se.vruntime = 0; |
fd2f4419 | 2203 | INIT_LIST_HEAD(&p->se.group_node); |
6cfb0d5d | 2204 | |
ad936d86 BP |
2205 | #ifdef CONFIG_FAIR_GROUP_SCHED |
2206 | p->se.cfs_rq = NULL; | |
2207 | #endif | |
2208 | ||
6cfb0d5d | 2209 | #ifdef CONFIG_SCHEDSTATS |
cb251765 | 2210 | /* Even if schedstat is disabled, there should not be garbage */ |
41acab88 | 2211 | memset(&p->se.statistics, 0, sizeof(p->se.statistics)); |
6cfb0d5d | 2212 | #endif |
476d139c | 2213 | |
aab03e05 | 2214 | RB_CLEAR_NODE(&p->dl.rb_node); |
40767b0d | 2215 | init_dl_task_timer(&p->dl); |
a5e7be3b | 2216 | __dl_clear_params(p); |
aab03e05 | 2217 | |
fa717060 | 2218 | INIT_LIST_HEAD(&p->rt.run_list); |
ff77e468 PZ |
2219 | p->rt.timeout = 0; |
2220 | p->rt.time_slice = sched_rr_timeslice; | |
2221 | p->rt.on_rq = 0; | |
2222 | p->rt.on_list = 0; | |
476d139c | 2223 | |
e107be36 AK |
2224 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2225 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
2226 | #endif | |
cbee9f88 PZ |
2227 | |
2228 | #ifdef CONFIG_NUMA_BALANCING | |
2229 | if (p->mm && atomic_read(&p->mm->mm_users) == 1) { | |
7e8d16b6 | 2230 | p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); |
cbee9f88 PZ |
2231 | p->mm->numa_scan_seq = 0; |
2232 | } | |
2233 | ||
5e1576ed RR |
2234 | if (clone_flags & CLONE_VM) |
2235 | p->numa_preferred_nid = current->numa_preferred_nid; | |
2236 | else | |
2237 | p->numa_preferred_nid = -1; | |
2238 | ||
cbee9f88 PZ |
2239 | p->node_stamp = 0ULL; |
2240 | p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; | |
4b96a29b | 2241 | p->numa_scan_period = sysctl_numa_balancing_scan_delay; |
cbee9f88 | 2242 | p->numa_work.next = &p->numa_work; |
44dba3d5 | 2243 | p->numa_faults = NULL; |
7e2703e6 RR |
2244 | p->last_task_numa_placement = 0; |
2245 | p->last_sum_exec_runtime = 0; | |
8c8a743c | 2246 | |
8c8a743c | 2247 | p->numa_group = NULL; |
cbee9f88 | 2248 | #endif /* CONFIG_NUMA_BALANCING */ |
dd41f596 IM |
2249 | } |
2250 | ||
2a595721 SD |
2251 | DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); |
2252 | ||
1a687c2e | 2253 | #ifdef CONFIG_NUMA_BALANCING |
c3b9bc5b | 2254 | |
1a687c2e MG |
2255 | void set_numabalancing_state(bool enabled) |
2256 | { | |
2257 | if (enabled) | |
2a595721 | 2258 | static_branch_enable(&sched_numa_balancing); |
1a687c2e | 2259 | else |
2a595721 | 2260 | static_branch_disable(&sched_numa_balancing); |
1a687c2e | 2261 | } |
54a43d54 AK |
2262 | |
2263 | #ifdef CONFIG_PROC_SYSCTL | |
2264 | int sysctl_numa_balancing(struct ctl_table *table, int write, | |
2265 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2266 | { | |
2267 | struct ctl_table t; | |
2268 | int err; | |
2a595721 | 2269 | int state = static_branch_likely(&sched_numa_balancing); |
54a43d54 AK |
2270 | |
2271 | if (write && !capable(CAP_SYS_ADMIN)) | |
2272 | return -EPERM; | |
2273 | ||
2274 | t = *table; | |
2275 | t.data = &state; | |
2276 | err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2277 | if (err < 0) | |
2278 | return err; | |
2279 | if (write) | |
2280 | set_numabalancing_state(state); | |
2281 | return err; | |
2282 | } | |
2283 | #endif | |
2284 | #endif | |
dd41f596 | 2285 | |
4698f88c JP |
2286 | #ifdef CONFIG_SCHEDSTATS |
2287 | ||
cb251765 | 2288 | DEFINE_STATIC_KEY_FALSE(sched_schedstats); |
4698f88c | 2289 | static bool __initdata __sched_schedstats = false; |
cb251765 | 2290 | |
cb251765 MG |
2291 | static void set_schedstats(bool enabled) |
2292 | { | |
2293 | if (enabled) | |
2294 | static_branch_enable(&sched_schedstats); | |
2295 | else | |
2296 | static_branch_disable(&sched_schedstats); | |
2297 | } | |
2298 | ||
2299 | void force_schedstat_enabled(void) | |
2300 | { | |
2301 | if (!schedstat_enabled()) { | |
2302 | pr_info("kernel profiling enabled schedstats, disable via kernel.sched_schedstats.\n"); | |
2303 | static_branch_enable(&sched_schedstats); | |
2304 | } | |
2305 | } | |
2306 | ||
2307 | static int __init setup_schedstats(char *str) | |
2308 | { | |
2309 | int ret = 0; | |
2310 | if (!str) | |
2311 | goto out; | |
2312 | ||
4698f88c JP |
2313 | /* |
2314 | * This code is called before jump labels have been set up, so we can't | |
2315 | * change the static branch directly just yet. Instead set a temporary | |
2316 | * variable so init_schedstats() can do it later. | |
2317 | */ | |
cb251765 | 2318 | if (!strcmp(str, "enable")) { |
4698f88c | 2319 | __sched_schedstats = true; |
cb251765 MG |
2320 | ret = 1; |
2321 | } else if (!strcmp(str, "disable")) { | |
4698f88c | 2322 | __sched_schedstats = false; |
cb251765 MG |
2323 | ret = 1; |
2324 | } | |
2325 | out: | |
2326 | if (!ret) | |
2327 | pr_warn("Unable to parse schedstats=\n"); | |
2328 | ||
2329 | return ret; | |
2330 | } | |
2331 | __setup("schedstats=", setup_schedstats); | |
2332 | ||
4698f88c JP |
2333 | static void __init init_schedstats(void) |
2334 | { | |
2335 | set_schedstats(__sched_schedstats); | |
2336 | } | |
2337 | ||
cb251765 MG |
2338 | #ifdef CONFIG_PROC_SYSCTL |
2339 | int sysctl_schedstats(struct ctl_table *table, int write, | |
2340 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2341 | { | |
2342 | struct ctl_table t; | |
2343 | int err; | |
2344 | int state = static_branch_likely(&sched_schedstats); | |
2345 | ||
2346 | if (write && !capable(CAP_SYS_ADMIN)) | |
2347 | return -EPERM; | |
2348 | ||
2349 | t = *table; | |
2350 | t.data = &state; | |
2351 | err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2352 | if (err < 0) | |
2353 | return err; | |
2354 | if (write) | |
2355 | set_schedstats(state); | |
2356 | return err; | |
2357 | } | |
4698f88c JP |
2358 | #endif /* CONFIG_PROC_SYSCTL */ |
2359 | #else /* !CONFIG_SCHEDSTATS */ | |
2360 | static inline void init_schedstats(void) {} | |
2361 | #endif /* CONFIG_SCHEDSTATS */ | |
dd41f596 IM |
2362 | |
2363 | /* | |
2364 | * fork()/clone()-time setup: | |
2365 | */ | |
aab03e05 | 2366 | int sched_fork(unsigned long clone_flags, struct task_struct *p) |
dd41f596 | 2367 | { |
0122ec5b | 2368 | unsigned long flags; |
dd41f596 IM |
2369 | int cpu = get_cpu(); |
2370 | ||
5e1576ed | 2371 | __sched_fork(clone_flags, p); |
06b83b5f | 2372 | /* |
7dc603c9 | 2373 | * We mark the process as NEW here. This guarantees that |
06b83b5f PZ |
2374 | * nobody will actually run it, and a signal or other external |
2375 | * event cannot wake it up and insert it on the runqueue either. | |
2376 | */ | |
7dc603c9 | 2377 | p->state = TASK_NEW; |
dd41f596 | 2378 | |
c350a04e MG |
2379 | /* |
2380 | * Make sure we do not leak PI boosting priority to the child. | |
2381 | */ | |
2382 | p->prio = current->normal_prio; | |
2383 | ||
b9dc29e7 MG |
2384 | /* |
2385 | * Revert to default priority/policy on fork if requested. | |
2386 | */ | |
2387 | if (unlikely(p->sched_reset_on_fork)) { | |
aab03e05 | 2388 | if (task_has_dl_policy(p) || task_has_rt_policy(p)) { |
b9dc29e7 | 2389 | p->policy = SCHED_NORMAL; |
6c697bdf | 2390 | p->static_prio = NICE_TO_PRIO(0); |
c350a04e MG |
2391 | p->rt_priority = 0; |
2392 | } else if (PRIO_TO_NICE(p->static_prio) < 0) | |
2393 | p->static_prio = NICE_TO_PRIO(0); | |
2394 | ||
2395 | p->prio = p->normal_prio = __normal_prio(p); | |
2396 | set_load_weight(p); | |
6c697bdf | 2397 | |
b9dc29e7 MG |
2398 | /* |
2399 | * We don't need the reset flag anymore after the fork. It has | |
2400 | * fulfilled its duty: | |
2401 | */ | |
2402 | p->sched_reset_on_fork = 0; | |
2403 | } | |
ca94c442 | 2404 | |
aab03e05 DF |
2405 | if (dl_prio(p->prio)) { |
2406 | put_cpu(); | |
2407 | return -EAGAIN; | |
2408 | } else if (rt_prio(p->prio)) { | |
2409 | p->sched_class = &rt_sched_class; | |
2410 | } else { | |
2ddbf952 | 2411 | p->sched_class = &fair_sched_class; |
aab03e05 | 2412 | } |
b29739f9 | 2413 | |
7dc603c9 | 2414 | init_entity_runnable_average(&p->se); |
cd29fe6f | 2415 | |
86951599 PZ |
2416 | /* |
2417 | * The child is not yet in the pid-hash so no cgroup attach races, | |
2418 | * and the cgroup is pinned to this child due to cgroup_fork() | |
2419 | * is ran before sched_fork(). | |
2420 | * | |
2421 | * Silence PROVE_RCU. | |
2422 | */ | |
0122ec5b | 2423 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
e210bffd PZ |
2424 | /* |
2425 | * We're setting the cpu for the first time, we don't migrate, | |
2426 | * so use __set_task_cpu(). | |
2427 | */ | |
2428 | __set_task_cpu(p, cpu); | |
2429 | if (p->sched_class->task_fork) | |
2430 | p->sched_class->task_fork(p); | |
0122ec5b | 2431 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
5f3edc1b | 2432 | |
f6db8347 | 2433 | #ifdef CONFIG_SCHED_INFO |
dd41f596 | 2434 | if (likely(sched_info_on())) |
52f17b6c | 2435 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 2436 | #endif |
3ca7a440 PZ |
2437 | #if defined(CONFIG_SMP) |
2438 | p->on_cpu = 0; | |
4866cde0 | 2439 | #endif |
01028747 | 2440 | init_task_preempt_count(p); |
806c09a7 | 2441 | #ifdef CONFIG_SMP |
917b627d | 2442 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
1baca4ce | 2443 | RB_CLEAR_NODE(&p->pushable_dl_tasks); |
806c09a7 | 2444 | #endif |
917b627d | 2445 | |
476d139c | 2446 | put_cpu(); |
aab03e05 | 2447 | return 0; |
1da177e4 LT |
2448 | } |
2449 | ||
332ac17e DF |
2450 | unsigned long to_ratio(u64 period, u64 runtime) |
2451 | { | |
2452 | if (runtime == RUNTIME_INF) | |
2453 | return 1ULL << 20; | |
2454 | ||
2455 | /* | |
2456 | * Doing this here saves a lot of checks in all | |
2457 | * the calling paths, and returning zero seems | |
2458 | * safe for them anyway. | |
2459 | */ | |
2460 | if (period == 0) | |
2461 | return 0; | |
2462 | ||
2463 | return div64_u64(runtime << 20, period); | |
2464 | } | |
2465 | ||
2466 | #ifdef CONFIG_SMP | |
2467 | inline struct dl_bw *dl_bw_of(int i) | |
2468 | { | |
f78f5b90 PM |
2469 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
2470 | "sched RCU must be held"); | |
332ac17e DF |
2471 | return &cpu_rq(i)->rd->dl_bw; |
2472 | } | |
2473 | ||
de212f18 | 2474 | static inline int dl_bw_cpus(int i) |
332ac17e | 2475 | { |
de212f18 PZ |
2476 | struct root_domain *rd = cpu_rq(i)->rd; |
2477 | int cpus = 0; | |
2478 | ||
f78f5b90 PM |
2479 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
2480 | "sched RCU must be held"); | |
de212f18 PZ |
2481 | for_each_cpu_and(i, rd->span, cpu_active_mask) |
2482 | cpus++; | |
2483 | ||
2484 | return cpus; | |
332ac17e DF |
2485 | } |
2486 | #else | |
2487 | inline struct dl_bw *dl_bw_of(int i) | |
2488 | { | |
2489 | return &cpu_rq(i)->dl.dl_bw; | |
2490 | } | |
2491 | ||
de212f18 | 2492 | static inline int dl_bw_cpus(int i) |
332ac17e DF |
2493 | { |
2494 | return 1; | |
2495 | } | |
2496 | #endif | |
2497 | ||
332ac17e DF |
2498 | /* |
2499 | * We must be sure that accepting a new task (or allowing changing the | |
2500 | * parameters of an existing one) is consistent with the bandwidth | |
2501 | * constraints. If yes, this function also accordingly updates the currently | |
2502 | * allocated bandwidth to reflect the new situation. | |
2503 | * | |
2504 | * This function is called while holding p's rq->lock. | |
40767b0d PZ |
2505 | * |
2506 | * XXX we should delay bw change until the task's 0-lag point, see | |
2507 | * __setparam_dl(). | |
332ac17e DF |
2508 | */ |
2509 | static int dl_overflow(struct task_struct *p, int policy, | |
2510 | const struct sched_attr *attr) | |
2511 | { | |
2512 | ||
2513 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); | |
4df1638c | 2514 | u64 period = attr->sched_period ?: attr->sched_deadline; |
332ac17e DF |
2515 | u64 runtime = attr->sched_runtime; |
2516 | u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; | |
de212f18 | 2517 | int cpus, err = -1; |
332ac17e | 2518 | |
fec148c0 XP |
2519 | /* !deadline task may carry old deadline bandwidth */ |
2520 | if (new_bw == p->dl.dl_bw && task_has_dl_policy(p)) | |
332ac17e DF |
2521 | return 0; |
2522 | ||
2523 | /* | |
2524 | * Either if a task, enters, leave, or stays -deadline but changes | |
2525 | * its parameters, we may need to update accordingly the total | |
2526 | * allocated bandwidth of the container. | |
2527 | */ | |
2528 | raw_spin_lock(&dl_b->lock); | |
de212f18 | 2529 | cpus = dl_bw_cpus(task_cpu(p)); |
332ac17e DF |
2530 | if (dl_policy(policy) && !task_has_dl_policy(p) && |
2531 | !__dl_overflow(dl_b, cpus, 0, new_bw)) { | |
2532 | __dl_add(dl_b, new_bw); | |
2533 | err = 0; | |
2534 | } else if (dl_policy(policy) && task_has_dl_policy(p) && | |
2535 | !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { | |
2536 | __dl_clear(dl_b, p->dl.dl_bw); | |
2537 | __dl_add(dl_b, new_bw); | |
2538 | err = 0; | |
2539 | } else if (!dl_policy(policy) && task_has_dl_policy(p)) { | |
2540 | __dl_clear(dl_b, p->dl.dl_bw); | |
2541 | err = 0; | |
2542 | } | |
2543 | raw_spin_unlock(&dl_b->lock); | |
2544 | ||
2545 | return err; | |
2546 | } | |
2547 | ||
2548 | extern void init_dl_bw(struct dl_bw *dl_b); | |
2549 | ||
1da177e4 LT |
2550 | /* |
2551 | * wake_up_new_task - wake up a newly created task for the first time. | |
2552 | * | |
2553 | * This function will do some initial scheduler statistics housekeeping | |
2554 | * that must be done for every newly created context, then puts the task | |
2555 | * on the runqueue and wakes it. | |
2556 | */ | |
3e51e3ed | 2557 | void wake_up_new_task(struct task_struct *p) |
1da177e4 | 2558 | { |
eb580751 | 2559 | struct rq_flags rf; |
dd41f596 | 2560 | struct rq *rq; |
fabf318e | 2561 | |
eb580751 | 2562 | raw_spin_lock_irqsave(&p->pi_lock, rf.flags); |
7dc603c9 | 2563 | p->state = TASK_RUNNING; |
fabf318e PZ |
2564 | #ifdef CONFIG_SMP |
2565 | /* | |
2566 | * Fork balancing, do it here and not earlier because: | |
2567 | * - cpus_allowed can change in the fork path | |
2568 | * - any previously selected cpu might disappear through hotplug | |
e210bffd PZ |
2569 | * |
2570 | * Use __set_task_cpu() to avoid calling sched_class::migrate_task_rq, | |
2571 | * as we're not fully set-up yet. | |
fabf318e | 2572 | */ |
e210bffd | 2573 | __set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); |
0017d735 | 2574 | #endif |
b7fa30c9 | 2575 | rq = __task_rq_lock(p, &rf); |
2b8c41da | 2576 | post_init_entity_util_avg(&p->se); |
0017d735 | 2577 | |
cd29fe6f | 2578 | activate_task(rq, p, 0); |
da0c1e65 | 2579 | p->on_rq = TASK_ON_RQ_QUEUED; |
fbd705a0 | 2580 | trace_sched_wakeup_new(p); |
a7558e01 | 2581 | check_preempt_curr(rq, p, WF_FORK); |
9a897c5a | 2582 | #ifdef CONFIG_SMP |
0aaafaab PZ |
2583 | if (p->sched_class->task_woken) { |
2584 | /* | |
2585 | * Nothing relies on rq->lock after this, so its fine to | |
2586 | * drop it. | |
2587 | */ | |
e7904a28 | 2588 | lockdep_unpin_lock(&rq->lock, rf.cookie); |
efbbd05a | 2589 | p->sched_class->task_woken(rq, p); |
e7904a28 | 2590 | lockdep_repin_lock(&rq->lock, rf.cookie); |
0aaafaab | 2591 | } |
9a897c5a | 2592 | #endif |
eb580751 | 2593 | task_rq_unlock(rq, p, &rf); |
1da177e4 LT |
2594 | } |
2595 | ||
e107be36 AK |
2596 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2597 | ||
1cde2930 PZ |
2598 | static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE; |
2599 | ||
2ecd9d29 PZ |
2600 | void preempt_notifier_inc(void) |
2601 | { | |
2602 | static_key_slow_inc(&preempt_notifier_key); | |
2603 | } | |
2604 | EXPORT_SYMBOL_GPL(preempt_notifier_inc); | |
2605 | ||
2606 | void preempt_notifier_dec(void) | |
2607 | { | |
2608 | static_key_slow_dec(&preempt_notifier_key); | |
2609 | } | |
2610 | EXPORT_SYMBOL_GPL(preempt_notifier_dec); | |
2611 | ||
e107be36 | 2612 | /** |
80dd99b3 | 2613 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
421cee29 | 2614 | * @notifier: notifier struct to register |
e107be36 AK |
2615 | */ |
2616 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
2617 | { | |
2ecd9d29 PZ |
2618 | if (!static_key_false(&preempt_notifier_key)) |
2619 | WARN(1, "registering preempt_notifier while notifiers disabled\n"); | |
2620 | ||
e107be36 AK |
2621 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
2622 | } | |
2623 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
2624 | ||
2625 | /** | |
2626 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 2627 | * @notifier: notifier struct to unregister |
e107be36 | 2628 | * |
d84525a8 | 2629 | * This is *not* safe to call from within a preemption notifier. |
e107be36 AK |
2630 | */ |
2631 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
2632 | { | |
2633 | hlist_del(¬ifier->link); | |
2634 | } | |
2635 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
2636 | ||
1cde2930 | 2637 | static void __fire_sched_in_preempt_notifiers(struct task_struct *curr) |
e107be36 AK |
2638 | { |
2639 | struct preempt_notifier *notifier; | |
e107be36 | 2640 | |
b67bfe0d | 2641 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
2642 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
2643 | } | |
2644 | ||
1cde2930 PZ |
2645 | static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2646 | { | |
2647 | if (static_key_false(&preempt_notifier_key)) | |
2648 | __fire_sched_in_preempt_notifiers(curr); | |
2649 | } | |
2650 | ||
e107be36 | 2651 | static void |
1cde2930 PZ |
2652 | __fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2653 | struct task_struct *next) | |
e107be36 AK |
2654 | { |
2655 | struct preempt_notifier *notifier; | |
e107be36 | 2656 | |
b67bfe0d | 2657 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
2658 | notifier->ops->sched_out(notifier, next); |
2659 | } | |
2660 | ||
1cde2930 PZ |
2661 | static __always_inline void |
2662 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
2663 | struct task_struct *next) | |
2664 | { | |
2665 | if (static_key_false(&preempt_notifier_key)) | |
2666 | __fire_sched_out_preempt_notifiers(curr, next); | |
2667 | } | |
2668 | ||
6d6bc0ad | 2669 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 | 2670 | |
1cde2930 | 2671 | static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
e107be36 AK |
2672 | { |
2673 | } | |
2674 | ||
1cde2930 | 2675 | static inline void |
e107be36 AK |
2676 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2677 | struct task_struct *next) | |
2678 | { | |
2679 | } | |
2680 | ||
6d6bc0ad | 2681 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 | 2682 | |
4866cde0 NP |
2683 | /** |
2684 | * prepare_task_switch - prepare to switch tasks | |
2685 | * @rq: the runqueue preparing to switch | |
421cee29 | 2686 | * @prev: the current task that is being switched out |
4866cde0 NP |
2687 | * @next: the task we are going to switch to. |
2688 | * | |
2689 | * This is called with the rq lock held and interrupts off. It must | |
2690 | * be paired with a subsequent finish_task_switch after the context | |
2691 | * switch. | |
2692 | * | |
2693 | * prepare_task_switch sets up locking and calls architecture specific | |
2694 | * hooks. | |
2695 | */ | |
e107be36 AK |
2696 | static inline void |
2697 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
2698 | struct task_struct *next) | |
4866cde0 | 2699 | { |
43148951 | 2700 | sched_info_switch(rq, prev, next); |
fe4b04fa | 2701 | perf_event_task_sched_out(prev, next); |
e107be36 | 2702 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
2703 | prepare_lock_switch(rq, next); |
2704 | prepare_arch_switch(next); | |
2705 | } | |
2706 | ||
1da177e4 LT |
2707 | /** |
2708 | * finish_task_switch - clean up after a task-switch | |
2709 | * @prev: the thread we just switched away from. | |
2710 | * | |
4866cde0 NP |
2711 | * finish_task_switch must be called after the context switch, paired |
2712 | * with a prepare_task_switch call before the context switch. | |
2713 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
2714 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
2715 | * |
2716 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 2717 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
2718 | * with the lock held can cause deadlocks; see schedule() for |
2719 | * details.) | |
dfa50b60 ON |
2720 | * |
2721 | * The context switch have flipped the stack from under us and restored the | |
2722 | * local variables which were saved when this task called schedule() in the | |
2723 | * past. prev == current is still correct but we need to recalculate this_rq | |
2724 | * because prev may have moved to another CPU. | |
1da177e4 | 2725 | */ |
dfa50b60 | 2726 | static struct rq *finish_task_switch(struct task_struct *prev) |
1da177e4 LT |
2727 | __releases(rq->lock) |
2728 | { | |
dfa50b60 | 2729 | struct rq *rq = this_rq(); |
1da177e4 | 2730 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 2731 | long prev_state; |
1da177e4 | 2732 | |
609ca066 PZ |
2733 | /* |
2734 | * The previous task will have left us with a preempt_count of 2 | |
2735 | * because it left us after: | |
2736 | * | |
2737 | * schedule() | |
2738 | * preempt_disable(); // 1 | |
2739 | * __schedule() | |
2740 | * raw_spin_lock_irq(&rq->lock) // 2 | |
2741 | * | |
2742 | * Also, see FORK_PREEMPT_COUNT. | |
2743 | */ | |
e2bf1c4b PZ |
2744 | if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET, |
2745 | "corrupted preempt_count: %s/%d/0x%x\n", | |
2746 | current->comm, current->pid, preempt_count())) | |
2747 | preempt_count_set(FORK_PREEMPT_COUNT); | |
609ca066 | 2748 | |
1da177e4 LT |
2749 | rq->prev_mm = NULL; |
2750 | ||
2751 | /* | |
2752 | * A task struct has one reference for the use as "current". | |
c394cc9f | 2753 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
2754 | * schedule one last time. The schedule call will never return, and |
2755 | * the scheduled task must drop that reference. | |
95913d97 PZ |
2756 | * |
2757 | * We must observe prev->state before clearing prev->on_cpu (in | |
2758 | * finish_lock_switch), otherwise a concurrent wakeup can get prev | |
2759 | * running on another CPU and we could rave with its RUNNING -> DEAD | |
2760 | * transition, resulting in a double drop. | |
1da177e4 | 2761 | */ |
55a101f8 | 2762 | prev_state = prev->state; |
bf9fae9f | 2763 | vtime_task_switch(prev); |
a8d757ef | 2764 | perf_event_task_sched_in(prev, current); |
4866cde0 | 2765 | finish_lock_switch(rq, prev); |
01f23e16 | 2766 | finish_arch_post_lock_switch(); |
e8fa1362 | 2767 | |
e107be36 | 2768 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
2769 | if (mm) |
2770 | mmdrop(mm); | |
c394cc9f | 2771 | if (unlikely(prev_state == TASK_DEAD)) { |
e6c390f2 DF |
2772 | if (prev->sched_class->task_dead) |
2773 | prev->sched_class->task_dead(prev); | |
2774 | ||
c6fd91f0 | 2775 | /* |
2776 | * Remove function-return probe instances associated with this | |
2777 | * task and put them back on the free list. | |
9761eea8 | 2778 | */ |
c6fd91f0 | 2779 | kprobe_flush_task(prev); |
1da177e4 | 2780 | put_task_struct(prev); |
c6fd91f0 | 2781 | } |
99e5ada9 | 2782 | |
de734f89 | 2783 | tick_nohz_task_switch(); |
dfa50b60 | 2784 | return rq; |
1da177e4 LT |
2785 | } |
2786 | ||
3f029d3c GH |
2787 | #ifdef CONFIG_SMP |
2788 | ||
3f029d3c | 2789 | /* rq->lock is NOT held, but preemption is disabled */ |
e3fca9e7 | 2790 | static void __balance_callback(struct rq *rq) |
3f029d3c | 2791 | { |
e3fca9e7 PZ |
2792 | struct callback_head *head, *next; |
2793 | void (*func)(struct rq *rq); | |
2794 | unsigned long flags; | |
3f029d3c | 2795 | |
e3fca9e7 PZ |
2796 | raw_spin_lock_irqsave(&rq->lock, flags); |
2797 | head = rq->balance_callback; | |
2798 | rq->balance_callback = NULL; | |
2799 | while (head) { | |
2800 | func = (void (*)(struct rq *))head->func; | |
2801 | next = head->next; | |
2802 | head->next = NULL; | |
2803 | head = next; | |
3f029d3c | 2804 | |
e3fca9e7 | 2805 | func(rq); |
3f029d3c | 2806 | } |
e3fca9e7 PZ |
2807 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
2808 | } | |
2809 | ||
2810 | static inline void balance_callback(struct rq *rq) | |
2811 | { | |
2812 | if (unlikely(rq->balance_callback)) | |
2813 | __balance_callback(rq); | |
3f029d3c GH |
2814 | } |
2815 | ||
2816 | #else | |
da19ab51 | 2817 | |
e3fca9e7 | 2818 | static inline void balance_callback(struct rq *rq) |
3f029d3c | 2819 | { |
1da177e4 LT |
2820 | } |
2821 | ||
3f029d3c GH |
2822 | #endif |
2823 | ||
1da177e4 LT |
2824 | /** |
2825 | * schedule_tail - first thing a freshly forked thread must call. | |
2826 | * @prev: the thread we just switched away from. | |
2827 | */ | |
722a9f92 | 2828 | asmlinkage __visible void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
2829 | __releases(rq->lock) |
2830 | { | |
1a43a14a | 2831 | struct rq *rq; |
da19ab51 | 2832 | |
609ca066 PZ |
2833 | /* |
2834 | * New tasks start with FORK_PREEMPT_COUNT, see there and | |
2835 | * finish_task_switch() for details. | |
2836 | * | |
2837 | * finish_task_switch() will drop rq->lock() and lower preempt_count | |
2838 | * and the preempt_enable() will end up enabling preemption (on | |
2839 | * PREEMPT_COUNT kernels). | |
2840 | */ | |
2841 | ||
dfa50b60 | 2842 | rq = finish_task_switch(prev); |
e3fca9e7 | 2843 | balance_callback(rq); |
1a43a14a | 2844 | preempt_enable(); |
70b97a7f | 2845 | |
1da177e4 | 2846 | if (current->set_child_tid) |
b488893a | 2847 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
2848 | } |
2849 | ||
2850 | /* | |
dfa50b60 | 2851 | * context_switch - switch to the new MM and the new thread's register state. |
1da177e4 | 2852 | */ |
04936948 | 2853 | static __always_inline struct rq * |
70b97a7f | 2854 | context_switch(struct rq *rq, struct task_struct *prev, |
e7904a28 | 2855 | struct task_struct *next, struct pin_cookie cookie) |
1da177e4 | 2856 | { |
dd41f596 | 2857 | struct mm_struct *mm, *oldmm; |
1da177e4 | 2858 | |
e107be36 | 2859 | prepare_task_switch(rq, prev, next); |
fe4b04fa | 2860 | |
dd41f596 IM |
2861 | mm = next->mm; |
2862 | oldmm = prev->active_mm; | |
9226d125 ZA |
2863 | /* |
2864 | * For paravirt, this is coupled with an exit in switch_to to | |
2865 | * combine the page table reload and the switch backend into | |
2866 | * one hypercall. | |
2867 | */ | |
224101ed | 2868 | arch_start_context_switch(prev); |
9226d125 | 2869 | |
31915ab4 | 2870 | if (!mm) { |
1da177e4 LT |
2871 | next->active_mm = oldmm; |
2872 | atomic_inc(&oldmm->mm_count); | |
2873 | enter_lazy_tlb(oldmm, next); | |
2874 | } else | |
f98db601 | 2875 | switch_mm_irqs_off(oldmm, mm, next); |
1da177e4 | 2876 | |
31915ab4 | 2877 | if (!prev->mm) { |
1da177e4 | 2878 | prev->active_mm = NULL; |
1da177e4 LT |
2879 | rq->prev_mm = oldmm; |
2880 | } | |
3a5f5e48 IM |
2881 | /* |
2882 | * Since the runqueue lock will be released by the next | |
2883 | * task (which is an invalid locking op but in the case | |
2884 | * of the scheduler it's an obvious special-case), so we | |
2885 | * do an early lockdep release here: | |
2886 | */ | |
e7904a28 | 2887 | lockdep_unpin_lock(&rq->lock, cookie); |
8a25d5de | 2888 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
2889 | |
2890 | /* Here we just switch the register state and the stack. */ | |
2891 | switch_to(prev, next, prev); | |
dd41f596 | 2892 | barrier(); |
dfa50b60 ON |
2893 | |
2894 | return finish_task_switch(prev); | |
1da177e4 LT |
2895 | } |
2896 | ||
2897 | /* | |
1c3e8264 | 2898 | * nr_running and nr_context_switches: |
1da177e4 LT |
2899 | * |
2900 | * externally visible scheduler statistics: current number of runnable | |
1c3e8264 | 2901 | * threads, total number of context switches performed since bootup. |
1da177e4 LT |
2902 | */ |
2903 | unsigned long nr_running(void) | |
2904 | { | |
2905 | unsigned long i, sum = 0; | |
2906 | ||
2907 | for_each_online_cpu(i) | |
2908 | sum += cpu_rq(i)->nr_running; | |
2909 | ||
2910 | return sum; | |
f711f609 | 2911 | } |
1da177e4 | 2912 | |
2ee507c4 TC |
2913 | /* |
2914 | * Check if only the current task is running on the cpu. | |
00cc1633 DD |
2915 | * |
2916 | * Caution: this function does not check that the caller has disabled | |
2917 | * preemption, thus the result might have a time-of-check-to-time-of-use | |
2918 | * race. The caller is responsible to use it correctly, for example: | |
2919 | * | |
2920 | * - from a non-preemptable section (of course) | |
2921 | * | |
2922 | * - from a thread that is bound to a single CPU | |
2923 | * | |
2924 | * - in a loop with very short iterations (e.g. a polling loop) | |
2ee507c4 TC |
2925 | */ |
2926 | bool single_task_running(void) | |
2927 | { | |
00cc1633 | 2928 | return raw_rq()->nr_running == 1; |
2ee507c4 TC |
2929 | } |
2930 | EXPORT_SYMBOL(single_task_running); | |
2931 | ||
1da177e4 | 2932 | unsigned long long nr_context_switches(void) |
46cb4b7c | 2933 | { |
cc94abfc SR |
2934 | int i; |
2935 | unsigned long long sum = 0; | |
46cb4b7c | 2936 | |
0a945022 | 2937 | for_each_possible_cpu(i) |
1da177e4 | 2938 | sum += cpu_rq(i)->nr_switches; |
46cb4b7c | 2939 | |
1da177e4 LT |
2940 | return sum; |
2941 | } | |
483b4ee6 | 2942 | |
1da177e4 LT |
2943 | unsigned long nr_iowait(void) |
2944 | { | |
2945 | unsigned long i, sum = 0; | |
483b4ee6 | 2946 | |
0a945022 | 2947 | for_each_possible_cpu(i) |
1da177e4 | 2948 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
46cb4b7c | 2949 | |
1da177e4 LT |
2950 | return sum; |
2951 | } | |
483b4ee6 | 2952 | |
8c215bd3 | 2953 | unsigned long nr_iowait_cpu(int cpu) |
69d25870 | 2954 | { |
8c215bd3 | 2955 | struct rq *this = cpu_rq(cpu); |
69d25870 AV |
2956 | return atomic_read(&this->nr_iowait); |
2957 | } | |
46cb4b7c | 2958 | |
372ba8cb MG |
2959 | void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) |
2960 | { | |
3289bdb4 PZ |
2961 | struct rq *rq = this_rq(); |
2962 | *nr_waiters = atomic_read(&rq->nr_iowait); | |
2963 | *load = rq->load.weight; | |
372ba8cb MG |
2964 | } |
2965 | ||
dd41f596 | 2966 | #ifdef CONFIG_SMP |
8a0be9ef | 2967 | |
46cb4b7c | 2968 | /* |
38022906 PZ |
2969 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2970 | * this point the task has the smallest effective memory and cache footprint. | |
46cb4b7c | 2971 | */ |
38022906 | 2972 | void sched_exec(void) |
46cb4b7c | 2973 | { |
38022906 | 2974 | struct task_struct *p = current; |
1da177e4 | 2975 | unsigned long flags; |
0017d735 | 2976 | int dest_cpu; |
46cb4b7c | 2977 | |
8f42ced9 | 2978 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
ac66f547 | 2979 | dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); |
0017d735 PZ |
2980 | if (dest_cpu == smp_processor_id()) |
2981 | goto unlock; | |
38022906 | 2982 | |
8f42ced9 | 2983 | if (likely(cpu_active(dest_cpu))) { |
969c7921 | 2984 | struct migration_arg arg = { p, dest_cpu }; |
46cb4b7c | 2985 | |
8f42ced9 PZ |
2986 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
2987 | stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); | |
1da177e4 LT |
2988 | return; |
2989 | } | |
0017d735 | 2990 | unlock: |
8f42ced9 | 2991 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 | 2992 | } |
dd41f596 | 2993 | |
1da177e4 LT |
2994 | #endif |
2995 | ||
1da177e4 | 2996 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3292beb3 | 2997 | DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); |
1da177e4 LT |
2998 | |
2999 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3292beb3 | 3000 | EXPORT_PER_CPU_SYMBOL(kernel_cpustat); |
1da177e4 | 3001 | |
6075620b GG |
3002 | /* |
3003 | * The function fair_sched_class.update_curr accesses the struct curr | |
3004 | * and its field curr->exec_start; when called from task_sched_runtime(), | |
3005 | * we observe a high rate of cache misses in practice. | |
3006 | * Prefetching this data results in improved performance. | |
3007 | */ | |
3008 | static inline void prefetch_curr_exec_start(struct task_struct *p) | |
3009 | { | |
3010 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
3011 | struct sched_entity *curr = (&p->se)->cfs_rq->curr; | |
3012 | #else | |
3013 | struct sched_entity *curr = (&task_rq(p)->cfs)->curr; | |
3014 | #endif | |
3015 | prefetch(curr); | |
3016 | prefetch(&curr->exec_start); | |
3017 | } | |
3018 | ||
c5f8d995 HS |
3019 | /* |
3020 | * Return accounted runtime for the task. | |
3021 | * In case the task is currently running, return the runtime plus current's | |
3022 | * pending runtime that have not been accounted yet. | |
3023 | */ | |
3024 | unsigned long long task_sched_runtime(struct task_struct *p) | |
3025 | { | |
eb580751 | 3026 | struct rq_flags rf; |
c5f8d995 | 3027 | struct rq *rq; |
6e998916 | 3028 | u64 ns; |
c5f8d995 | 3029 | |
911b2898 PZ |
3030 | #if defined(CONFIG_64BIT) && defined(CONFIG_SMP) |
3031 | /* | |
3032 | * 64-bit doesn't need locks to atomically read a 64bit value. | |
3033 | * So we have a optimization chance when the task's delta_exec is 0. | |
3034 | * Reading ->on_cpu is racy, but this is ok. | |
3035 | * | |
3036 | * If we race with it leaving cpu, we'll take a lock. So we're correct. | |
3037 | * If we race with it entering cpu, unaccounted time is 0. This is | |
3038 | * indistinguishable from the read occurring a few cycles earlier. | |
4036ac15 MG |
3039 | * If we see ->on_cpu without ->on_rq, the task is leaving, and has |
3040 | * been accounted, so we're correct here as well. | |
911b2898 | 3041 | */ |
da0c1e65 | 3042 | if (!p->on_cpu || !task_on_rq_queued(p)) |
911b2898 PZ |
3043 | return p->se.sum_exec_runtime; |
3044 | #endif | |
3045 | ||
eb580751 | 3046 | rq = task_rq_lock(p, &rf); |
6e998916 SG |
3047 | /* |
3048 | * Must be ->curr _and_ ->on_rq. If dequeued, we would | |
3049 | * project cycles that may never be accounted to this | |
3050 | * thread, breaking clock_gettime(). | |
3051 | */ | |
3052 | if (task_current(rq, p) && task_on_rq_queued(p)) { | |
6075620b | 3053 | prefetch_curr_exec_start(p); |
6e998916 SG |
3054 | update_rq_clock(rq); |
3055 | p->sched_class->update_curr(rq); | |
3056 | } | |
3057 | ns = p->se.sum_exec_runtime; | |
eb580751 | 3058 | task_rq_unlock(rq, p, &rf); |
c5f8d995 HS |
3059 | |
3060 | return ns; | |
3061 | } | |
48f24c4d | 3062 | |
7835b98b CL |
3063 | /* |
3064 | * This function gets called by the timer code, with HZ frequency. | |
3065 | * We call it with interrupts disabled. | |
7835b98b CL |
3066 | */ |
3067 | void scheduler_tick(void) | |
3068 | { | |
7835b98b CL |
3069 | int cpu = smp_processor_id(); |
3070 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 3071 | struct task_struct *curr = rq->curr; |
3e51f33f PZ |
3072 | |
3073 | sched_clock_tick(); | |
dd41f596 | 3074 | |
05fa785c | 3075 | raw_spin_lock(&rq->lock); |
3e51f33f | 3076 | update_rq_clock(rq); |
fa85ae24 | 3077 | curr->sched_class->task_tick(rq, curr, 0); |
cee1afce | 3078 | cpu_load_update_active(rq); |
3289bdb4 | 3079 | calc_global_load_tick(rq); |
05fa785c | 3080 | raw_spin_unlock(&rq->lock); |
7835b98b | 3081 | |
e9d2b064 | 3082 | perf_event_task_tick(); |
e220d2dc | 3083 | |
e418e1c2 | 3084 | #ifdef CONFIG_SMP |
6eb57e0d | 3085 | rq->idle_balance = idle_cpu(cpu); |
7caff66f | 3086 | trigger_load_balance(rq); |
e418e1c2 | 3087 | #endif |
265f22a9 | 3088 | rq_last_tick_reset(rq); |
1da177e4 LT |
3089 | } |
3090 | ||
265f22a9 FW |
3091 | #ifdef CONFIG_NO_HZ_FULL |
3092 | /** | |
3093 | * scheduler_tick_max_deferment | |
3094 | * | |
3095 | * Keep at least one tick per second when a single | |
3096 | * active task is running because the scheduler doesn't | |
3097 | * yet completely support full dynticks environment. | |
3098 | * | |
3099 | * This makes sure that uptime, CFS vruntime, load | |
3100 | * balancing, etc... continue to move forward, even | |
3101 | * with a very low granularity. | |
e69f6186 YB |
3102 | * |
3103 | * Return: Maximum deferment in nanoseconds. | |
265f22a9 FW |
3104 | */ |
3105 | u64 scheduler_tick_max_deferment(void) | |
3106 | { | |
3107 | struct rq *rq = this_rq(); | |
316c1608 | 3108 | unsigned long next, now = READ_ONCE(jiffies); |
265f22a9 FW |
3109 | |
3110 | next = rq->last_sched_tick + HZ; | |
3111 | ||
3112 | if (time_before_eq(next, now)) | |
3113 | return 0; | |
3114 | ||
8fe8ff09 | 3115 | return jiffies_to_nsecs(next - now); |
1da177e4 | 3116 | } |
265f22a9 | 3117 | #endif |
1da177e4 | 3118 | |
7e49fcce SR |
3119 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
3120 | defined(CONFIG_PREEMPT_TRACER)) | |
47252cfb SR |
3121 | /* |
3122 | * If the value passed in is equal to the current preempt count | |
3123 | * then we just disabled preemption. Start timing the latency. | |
3124 | */ | |
3125 | static inline void preempt_latency_start(int val) | |
3126 | { | |
3127 | if (preempt_count() == val) { | |
3128 | unsigned long ip = get_lock_parent_ip(); | |
3129 | #ifdef CONFIG_DEBUG_PREEMPT | |
3130 | current->preempt_disable_ip = ip; | |
3131 | #endif | |
3132 | trace_preempt_off(CALLER_ADDR0, ip); | |
3133 | } | |
3134 | } | |
7e49fcce | 3135 | |
edafe3a5 | 3136 | void preempt_count_add(int val) |
1da177e4 | 3137 | { |
6cd8a4bb | 3138 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3139 | /* |
3140 | * Underflow? | |
3141 | */ | |
9a11b49a IM |
3142 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3143 | return; | |
6cd8a4bb | 3144 | #endif |
bdb43806 | 3145 | __preempt_count_add(val); |
6cd8a4bb | 3146 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3147 | /* |
3148 | * Spinlock count overflowing soon? | |
3149 | */ | |
33859f7f MOS |
3150 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3151 | PREEMPT_MASK - 10); | |
6cd8a4bb | 3152 | #endif |
47252cfb | 3153 | preempt_latency_start(val); |
1da177e4 | 3154 | } |
bdb43806 | 3155 | EXPORT_SYMBOL(preempt_count_add); |
edafe3a5 | 3156 | NOKPROBE_SYMBOL(preempt_count_add); |
1da177e4 | 3157 | |
47252cfb SR |
3158 | /* |
3159 | * If the value passed in equals to the current preempt count | |
3160 | * then we just enabled preemption. Stop timing the latency. | |
3161 | */ | |
3162 | static inline void preempt_latency_stop(int val) | |
3163 | { | |
3164 | if (preempt_count() == val) | |
3165 | trace_preempt_on(CALLER_ADDR0, get_lock_parent_ip()); | |
3166 | } | |
3167 | ||
edafe3a5 | 3168 | void preempt_count_sub(int val) |
1da177e4 | 3169 | { |
6cd8a4bb | 3170 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3171 | /* |
3172 | * Underflow? | |
3173 | */ | |
01e3eb82 | 3174 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
9a11b49a | 3175 | return; |
1da177e4 LT |
3176 | /* |
3177 | * Is the spinlock portion underflowing? | |
3178 | */ | |
9a11b49a IM |
3179 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3180 | !(preempt_count() & PREEMPT_MASK))) | |
3181 | return; | |
6cd8a4bb | 3182 | #endif |
9a11b49a | 3183 | |
47252cfb | 3184 | preempt_latency_stop(val); |
bdb43806 | 3185 | __preempt_count_sub(val); |
1da177e4 | 3186 | } |
bdb43806 | 3187 | EXPORT_SYMBOL(preempt_count_sub); |
edafe3a5 | 3188 | NOKPROBE_SYMBOL(preempt_count_sub); |
1da177e4 | 3189 | |
47252cfb SR |
3190 | #else |
3191 | static inline void preempt_latency_start(int val) { } | |
3192 | static inline void preempt_latency_stop(int val) { } | |
1da177e4 LT |
3193 | #endif |
3194 | ||
3195 | /* | |
dd41f596 | 3196 | * Print scheduling while atomic bug: |
1da177e4 | 3197 | */ |
dd41f596 | 3198 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3199 | { |
d1c6d149 VN |
3200 | /* Save this before calling printk(), since that will clobber it */ |
3201 | unsigned long preempt_disable_ip = get_preempt_disable_ip(current); | |
3202 | ||
664dfa65 DJ |
3203 | if (oops_in_progress) |
3204 | return; | |
3205 | ||
3df0fc5b PZ |
3206 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
3207 | prev->comm, prev->pid, preempt_count()); | |
838225b4 | 3208 | |
dd41f596 | 3209 | debug_show_held_locks(prev); |
e21f5b15 | 3210 | print_modules(); |
dd41f596 IM |
3211 | if (irqs_disabled()) |
3212 | print_irqtrace_events(prev); | |
d1c6d149 VN |
3213 | if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) |
3214 | && in_atomic_preempt_off()) { | |
8f47b187 | 3215 | pr_err("Preemption disabled at:"); |
d1c6d149 | 3216 | print_ip_sym(preempt_disable_ip); |
8f47b187 TG |
3217 | pr_cont("\n"); |
3218 | } | |
748c7201 DBO |
3219 | if (panic_on_warn) |
3220 | panic("scheduling while atomic\n"); | |
3221 | ||
6135fc1e | 3222 | dump_stack(); |
373d4d09 | 3223 | add_taint(TAINT_WARN, LOCKDEP_STILL_OK); |
dd41f596 | 3224 | } |
1da177e4 | 3225 | |
dd41f596 IM |
3226 | /* |
3227 | * Various schedule()-time debugging checks and statistics: | |
3228 | */ | |
3229 | static inline void schedule_debug(struct task_struct *prev) | |
3230 | { | |
0d9e2632 | 3231 | #ifdef CONFIG_SCHED_STACK_END_CHECK |
29d64551 JH |
3232 | if (task_stack_end_corrupted(prev)) |
3233 | panic("corrupted stack end detected inside scheduler\n"); | |
0d9e2632 | 3234 | #endif |
b99def8b | 3235 | |
1dc0fffc | 3236 | if (unlikely(in_atomic_preempt_off())) { |
dd41f596 | 3237 | __schedule_bug(prev); |
1dc0fffc PZ |
3238 | preempt_count_set(PREEMPT_DISABLED); |
3239 | } | |
b3fbab05 | 3240 | rcu_sleep_check(); |
dd41f596 | 3241 | |
1da177e4 LT |
3242 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3243 | ||
ae92882e | 3244 | schedstat_inc(this_rq()->sched_count); |
dd41f596 IM |
3245 | } |
3246 | ||
3247 | /* | |
3248 | * Pick up the highest-prio task: | |
3249 | */ | |
3250 | static inline struct task_struct * | |
e7904a28 | 3251 | pick_next_task(struct rq *rq, struct task_struct *prev, struct pin_cookie cookie) |
dd41f596 | 3252 | { |
37e117c0 | 3253 | const struct sched_class *class = &fair_sched_class; |
dd41f596 | 3254 | struct task_struct *p; |
1da177e4 LT |
3255 | |
3256 | /* | |
dd41f596 IM |
3257 | * Optimization: we know that if all tasks are in |
3258 | * the fair class we can call that function directly: | |
1da177e4 | 3259 | */ |
37e117c0 | 3260 | if (likely(prev->sched_class == class && |
38033c37 | 3261 | rq->nr_running == rq->cfs.h_nr_running)) { |
e7904a28 | 3262 | p = fair_sched_class.pick_next_task(rq, prev, cookie); |
6ccdc84b PZ |
3263 | if (unlikely(p == RETRY_TASK)) |
3264 | goto again; | |
3265 | ||
3266 | /* assumes fair_sched_class->next == idle_sched_class */ | |
3267 | if (unlikely(!p)) | |
e7904a28 | 3268 | p = idle_sched_class.pick_next_task(rq, prev, cookie); |
6ccdc84b PZ |
3269 | |
3270 | return p; | |
1da177e4 LT |
3271 | } |
3272 | ||
37e117c0 | 3273 | again: |
34f971f6 | 3274 | for_each_class(class) { |
e7904a28 | 3275 | p = class->pick_next_task(rq, prev, cookie); |
37e117c0 PZ |
3276 | if (p) { |
3277 | if (unlikely(p == RETRY_TASK)) | |
3278 | goto again; | |
dd41f596 | 3279 | return p; |
37e117c0 | 3280 | } |
dd41f596 | 3281 | } |
34f971f6 PZ |
3282 | |
3283 | BUG(); /* the idle class will always have a runnable task */ | |
dd41f596 | 3284 | } |
1da177e4 | 3285 | |
dd41f596 | 3286 | /* |
c259e01a | 3287 | * __schedule() is the main scheduler function. |
edde96ea PE |
3288 | * |
3289 | * The main means of driving the scheduler and thus entering this function are: | |
3290 | * | |
3291 | * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. | |
3292 | * | |
3293 | * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return | |
3294 | * paths. For example, see arch/x86/entry_64.S. | |
3295 | * | |
3296 | * To drive preemption between tasks, the scheduler sets the flag in timer | |
3297 | * interrupt handler scheduler_tick(). | |
3298 | * | |
3299 | * 3. Wakeups don't really cause entry into schedule(). They add a | |
3300 | * task to the run-queue and that's it. | |
3301 | * | |
3302 | * Now, if the new task added to the run-queue preempts the current | |
3303 | * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets | |
3304 | * called on the nearest possible occasion: | |
3305 | * | |
3306 | * - If the kernel is preemptible (CONFIG_PREEMPT=y): | |
3307 | * | |
3308 | * - in syscall or exception context, at the next outmost | |
3309 | * preempt_enable(). (this might be as soon as the wake_up()'s | |
3310 | * spin_unlock()!) | |
3311 | * | |
3312 | * - in IRQ context, return from interrupt-handler to | |
3313 | * preemptible context | |
3314 | * | |
3315 | * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) | |
3316 | * then at the next: | |
3317 | * | |
3318 | * - cond_resched() call | |
3319 | * - explicit schedule() call | |
3320 | * - return from syscall or exception to user-space | |
3321 | * - return from interrupt-handler to user-space | |
bfd9b2b5 | 3322 | * |
b30f0e3f | 3323 | * WARNING: must be called with preemption disabled! |
dd41f596 | 3324 | */ |
499d7955 | 3325 | static void __sched notrace __schedule(bool preempt) |
dd41f596 IM |
3326 | { |
3327 | struct task_struct *prev, *next; | |
67ca7bde | 3328 | unsigned long *switch_count; |
e7904a28 | 3329 | struct pin_cookie cookie; |
dd41f596 | 3330 | struct rq *rq; |
31656519 | 3331 | int cpu; |
dd41f596 | 3332 | |
dd41f596 IM |
3333 | cpu = smp_processor_id(); |
3334 | rq = cpu_rq(cpu); | |
dd41f596 | 3335 | prev = rq->curr; |
dd41f596 | 3336 | |
b99def8b PZ |
3337 | /* |
3338 | * do_exit() calls schedule() with preemption disabled as an exception; | |
3339 | * however we must fix that up, otherwise the next task will see an | |
3340 | * inconsistent (higher) preempt count. | |
3341 | * | |
3342 | * It also avoids the below schedule_debug() test from complaining | |
3343 | * about this. | |
3344 | */ | |
3345 | if (unlikely(prev->state == TASK_DEAD)) | |
3346 | preempt_enable_no_resched_notrace(); | |
3347 | ||
dd41f596 | 3348 | schedule_debug(prev); |
1da177e4 | 3349 | |
31656519 | 3350 | if (sched_feat(HRTICK)) |
f333fdc9 | 3351 | hrtick_clear(rq); |
8f4d37ec | 3352 | |
46a5d164 PM |
3353 | local_irq_disable(); |
3354 | rcu_note_context_switch(); | |
3355 | ||
e0acd0a6 ON |
3356 | /* |
3357 | * Make sure that signal_pending_state()->signal_pending() below | |
3358 | * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) | |
3359 | * done by the caller to avoid the race with signal_wake_up(). | |
3360 | */ | |
3361 | smp_mb__before_spinlock(); | |
46a5d164 | 3362 | raw_spin_lock(&rq->lock); |
e7904a28 | 3363 | cookie = lockdep_pin_lock(&rq->lock); |
1da177e4 | 3364 | |
9edfbfed PZ |
3365 | rq->clock_skip_update <<= 1; /* promote REQ to ACT */ |
3366 | ||
246d86b5 | 3367 | switch_count = &prev->nivcsw; |
fc13aeba | 3368 | if (!preempt && prev->state) { |
21aa9af0 | 3369 | if (unlikely(signal_pending_state(prev->state, prev))) { |
1da177e4 | 3370 | prev->state = TASK_RUNNING; |
21aa9af0 | 3371 | } else { |
2acca55e PZ |
3372 | deactivate_task(rq, prev, DEQUEUE_SLEEP); |
3373 | prev->on_rq = 0; | |
3374 | ||
21aa9af0 | 3375 | /* |
2acca55e PZ |
3376 | * If a worker went to sleep, notify and ask workqueue |
3377 | * whether it wants to wake up a task to maintain | |
3378 | * concurrency. | |
21aa9af0 TH |
3379 | */ |
3380 | if (prev->flags & PF_WQ_WORKER) { | |
3381 | struct task_struct *to_wakeup; | |
3382 | ||
9b7f6597 | 3383 | to_wakeup = wq_worker_sleeping(prev); |
21aa9af0 | 3384 | if (to_wakeup) |
e7904a28 | 3385 | try_to_wake_up_local(to_wakeup, cookie); |
21aa9af0 | 3386 | } |
21aa9af0 | 3387 | } |
dd41f596 | 3388 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3389 | } |
3390 | ||
9edfbfed | 3391 | if (task_on_rq_queued(prev)) |
606dba2e PZ |
3392 | update_rq_clock(rq); |
3393 | ||
e7904a28 | 3394 | next = pick_next_task(rq, prev, cookie); |
f26f9aff | 3395 | clear_tsk_need_resched(prev); |
f27dde8d | 3396 | clear_preempt_need_resched(); |
9edfbfed | 3397 | rq->clock_skip_update = 0; |
1da177e4 | 3398 | |
1da177e4 | 3399 | if (likely(prev != next)) { |
1da177e4 LT |
3400 | rq->nr_switches++; |
3401 | rq->curr = next; | |
3402 | ++*switch_count; | |
3403 | ||
c73464b1 | 3404 | trace_sched_switch(preempt, prev, next); |
e7904a28 | 3405 | rq = context_switch(rq, prev, next, cookie); /* unlocks the rq */ |
cbce1a68 | 3406 | } else { |
e7904a28 | 3407 | lockdep_unpin_lock(&rq->lock, cookie); |
05fa785c | 3408 | raw_spin_unlock_irq(&rq->lock); |
cbce1a68 | 3409 | } |
1da177e4 | 3410 | |
e3fca9e7 | 3411 | balance_callback(rq); |
1da177e4 | 3412 | } |
c259e01a | 3413 | |
9c40cef2 TG |
3414 | static inline void sched_submit_work(struct task_struct *tsk) |
3415 | { | |
3c7d5184 | 3416 | if (!tsk->state || tsk_is_pi_blocked(tsk)) |
9c40cef2 TG |
3417 | return; |
3418 | /* | |
3419 | * If we are going to sleep and we have plugged IO queued, | |
3420 | * make sure to submit it to avoid deadlocks. | |
3421 | */ | |
3422 | if (blk_needs_flush_plug(tsk)) | |
3423 | blk_schedule_flush_plug(tsk); | |
3424 | } | |
3425 | ||
722a9f92 | 3426 | asmlinkage __visible void __sched schedule(void) |
c259e01a | 3427 | { |
9c40cef2 TG |
3428 | struct task_struct *tsk = current; |
3429 | ||
3430 | sched_submit_work(tsk); | |
bfd9b2b5 | 3431 | do { |
b30f0e3f | 3432 | preempt_disable(); |
fc13aeba | 3433 | __schedule(false); |
b30f0e3f | 3434 | sched_preempt_enable_no_resched(); |
bfd9b2b5 | 3435 | } while (need_resched()); |
c259e01a | 3436 | } |
1da177e4 LT |
3437 | EXPORT_SYMBOL(schedule); |
3438 | ||
91d1aa43 | 3439 | #ifdef CONFIG_CONTEXT_TRACKING |
722a9f92 | 3440 | asmlinkage __visible void __sched schedule_user(void) |
20ab65e3 FW |
3441 | { |
3442 | /* | |
3443 | * If we come here after a random call to set_need_resched(), | |
3444 | * or we have been woken up remotely but the IPI has not yet arrived, | |
3445 | * we haven't yet exited the RCU idle mode. Do it here manually until | |
3446 | * we find a better solution. | |
7cc78f8f AL |
3447 | * |
3448 | * NB: There are buggy callers of this function. Ideally we | |
c467ea76 | 3449 | * should warn if prev_state != CONTEXT_USER, but that will trigger |
7cc78f8f | 3450 | * too frequently to make sense yet. |
20ab65e3 | 3451 | */ |
7cc78f8f | 3452 | enum ctx_state prev_state = exception_enter(); |
20ab65e3 | 3453 | schedule(); |
7cc78f8f | 3454 | exception_exit(prev_state); |
20ab65e3 FW |
3455 | } |
3456 | #endif | |
3457 | ||
c5491ea7 TG |
3458 | /** |
3459 | * schedule_preempt_disabled - called with preemption disabled | |
3460 | * | |
3461 | * Returns with preemption disabled. Note: preempt_count must be 1 | |
3462 | */ | |
3463 | void __sched schedule_preempt_disabled(void) | |
3464 | { | |
ba74c144 | 3465 | sched_preempt_enable_no_resched(); |
c5491ea7 TG |
3466 | schedule(); |
3467 | preempt_disable(); | |
3468 | } | |
3469 | ||
06b1f808 | 3470 | static void __sched notrace preempt_schedule_common(void) |
a18b5d01 FW |
3471 | { |
3472 | do { | |
47252cfb SR |
3473 | /* |
3474 | * Because the function tracer can trace preempt_count_sub() | |
3475 | * and it also uses preempt_enable/disable_notrace(), if | |
3476 | * NEED_RESCHED is set, the preempt_enable_notrace() called | |
3477 | * by the function tracer will call this function again and | |
3478 | * cause infinite recursion. | |
3479 | * | |
3480 | * Preemption must be disabled here before the function | |
3481 | * tracer can trace. Break up preempt_disable() into two | |
3482 | * calls. One to disable preemption without fear of being | |
3483 | * traced. The other to still record the preemption latency, | |
3484 | * which can also be traced by the function tracer. | |
3485 | */ | |
499d7955 | 3486 | preempt_disable_notrace(); |
47252cfb | 3487 | preempt_latency_start(1); |
fc13aeba | 3488 | __schedule(true); |
47252cfb | 3489 | preempt_latency_stop(1); |
499d7955 | 3490 | preempt_enable_no_resched_notrace(); |
a18b5d01 FW |
3491 | |
3492 | /* | |
3493 | * Check again in case we missed a preemption opportunity | |
3494 | * between schedule and now. | |
3495 | */ | |
a18b5d01 FW |
3496 | } while (need_resched()); |
3497 | } | |
3498 | ||
1da177e4 LT |
3499 | #ifdef CONFIG_PREEMPT |
3500 | /* | |
2ed6e34f | 3501 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 3502 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
3503 | * occur there and call schedule directly. |
3504 | */ | |
722a9f92 | 3505 | asmlinkage __visible void __sched notrace preempt_schedule(void) |
1da177e4 | 3506 | { |
1da177e4 LT |
3507 | /* |
3508 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 3509 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 3510 | */ |
fbb00b56 | 3511 | if (likely(!preemptible())) |
1da177e4 LT |
3512 | return; |
3513 | ||
a18b5d01 | 3514 | preempt_schedule_common(); |
1da177e4 | 3515 | } |
376e2424 | 3516 | NOKPROBE_SYMBOL(preempt_schedule); |
1da177e4 | 3517 | EXPORT_SYMBOL(preempt_schedule); |
009f60e2 | 3518 | |
009f60e2 | 3519 | /** |
4eaca0a8 | 3520 | * preempt_schedule_notrace - preempt_schedule called by tracing |
009f60e2 ON |
3521 | * |
3522 | * The tracing infrastructure uses preempt_enable_notrace to prevent | |
3523 | * recursion and tracing preempt enabling caused by the tracing | |
3524 | * infrastructure itself. But as tracing can happen in areas coming | |
3525 | * from userspace or just about to enter userspace, a preempt enable | |
3526 | * can occur before user_exit() is called. This will cause the scheduler | |
3527 | * to be called when the system is still in usermode. | |
3528 | * | |
3529 | * To prevent this, the preempt_enable_notrace will use this function | |
3530 | * instead of preempt_schedule() to exit user context if needed before | |
3531 | * calling the scheduler. | |
3532 | */ | |
4eaca0a8 | 3533 | asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) |
009f60e2 ON |
3534 | { |
3535 | enum ctx_state prev_ctx; | |
3536 | ||
3537 | if (likely(!preemptible())) | |
3538 | return; | |
3539 | ||
3540 | do { | |
47252cfb SR |
3541 | /* |
3542 | * Because the function tracer can trace preempt_count_sub() | |
3543 | * and it also uses preempt_enable/disable_notrace(), if | |
3544 | * NEED_RESCHED is set, the preempt_enable_notrace() called | |
3545 | * by the function tracer will call this function again and | |
3546 | * cause infinite recursion. | |
3547 | * | |
3548 | * Preemption must be disabled here before the function | |
3549 | * tracer can trace. Break up preempt_disable() into two | |
3550 | * calls. One to disable preemption without fear of being | |
3551 | * traced. The other to still record the preemption latency, | |
3552 | * which can also be traced by the function tracer. | |
3553 | */ | |
3d8f74dd | 3554 | preempt_disable_notrace(); |
47252cfb | 3555 | preempt_latency_start(1); |
009f60e2 ON |
3556 | /* |
3557 | * Needs preempt disabled in case user_exit() is traced | |
3558 | * and the tracer calls preempt_enable_notrace() causing | |
3559 | * an infinite recursion. | |
3560 | */ | |
3561 | prev_ctx = exception_enter(); | |
fc13aeba | 3562 | __schedule(true); |
009f60e2 ON |
3563 | exception_exit(prev_ctx); |
3564 | ||
47252cfb | 3565 | preempt_latency_stop(1); |
3d8f74dd | 3566 | preempt_enable_no_resched_notrace(); |
009f60e2 ON |
3567 | } while (need_resched()); |
3568 | } | |
4eaca0a8 | 3569 | EXPORT_SYMBOL_GPL(preempt_schedule_notrace); |
009f60e2 | 3570 | |
32e475d7 | 3571 | #endif /* CONFIG_PREEMPT */ |
1da177e4 LT |
3572 | |
3573 | /* | |
2ed6e34f | 3574 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3575 | * off of irq context. |
3576 | * Note, that this is called and return with irqs disabled. This will | |
3577 | * protect us against recursive calling from irq. | |
3578 | */ | |
722a9f92 | 3579 | asmlinkage __visible void __sched preempt_schedule_irq(void) |
1da177e4 | 3580 | { |
b22366cd | 3581 | enum ctx_state prev_state; |
6478d880 | 3582 | |
2ed6e34f | 3583 | /* Catch callers which need to be fixed */ |
f27dde8d | 3584 | BUG_ON(preempt_count() || !irqs_disabled()); |
1da177e4 | 3585 | |
b22366cd FW |
3586 | prev_state = exception_enter(); |
3587 | ||
3a5c359a | 3588 | do { |
3d8f74dd | 3589 | preempt_disable(); |
3a5c359a | 3590 | local_irq_enable(); |
fc13aeba | 3591 | __schedule(true); |
3a5c359a | 3592 | local_irq_disable(); |
3d8f74dd | 3593 | sched_preempt_enable_no_resched(); |
5ed0cec0 | 3594 | } while (need_resched()); |
b22366cd FW |
3595 | |
3596 | exception_exit(prev_state); | |
1da177e4 LT |
3597 | } |
3598 | ||
63859d4f | 3599 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
95cdf3b7 | 3600 | void *key) |
1da177e4 | 3601 | { |
63859d4f | 3602 | return try_to_wake_up(curr->private, mode, wake_flags); |
1da177e4 | 3603 | } |
1da177e4 LT |
3604 | EXPORT_SYMBOL(default_wake_function); |
3605 | ||
b29739f9 IM |
3606 | #ifdef CONFIG_RT_MUTEXES |
3607 | ||
3608 | /* | |
3609 | * rt_mutex_setprio - set the current priority of a task | |
3610 | * @p: task | |
3611 | * @prio: prio value (kernel-internal form) | |
3612 | * | |
3613 | * This function changes the 'effective' priority of a task. It does | |
3614 | * not touch ->normal_prio like __setscheduler(). | |
3615 | * | |
c365c292 TG |
3616 | * Used by the rt_mutex code to implement priority inheritance |
3617 | * logic. Call site only calls if the priority of the task changed. | |
b29739f9 | 3618 | */ |
36c8b586 | 3619 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 | 3620 | { |
ff77e468 | 3621 | int oldprio, queued, running, queue_flag = DEQUEUE_SAVE | DEQUEUE_MOVE; |
83ab0aa0 | 3622 | const struct sched_class *prev_class; |
eb580751 PZ |
3623 | struct rq_flags rf; |
3624 | struct rq *rq; | |
b29739f9 | 3625 | |
aab03e05 | 3626 | BUG_ON(prio > MAX_PRIO); |
b29739f9 | 3627 | |
eb580751 | 3628 | rq = __task_rq_lock(p, &rf); |
b29739f9 | 3629 | |
1c4dd99b TG |
3630 | /* |
3631 | * Idle task boosting is a nono in general. There is one | |
3632 | * exception, when PREEMPT_RT and NOHZ is active: | |
3633 | * | |
3634 | * The idle task calls get_next_timer_interrupt() and holds | |
3635 | * the timer wheel base->lock on the CPU and another CPU wants | |
3636 | * to access the timer (probably to cancel it). We can safely | |
3637 | * ignore the boosting request, as the idle CPU runs this code | |
3638 | * with interrupts disabled and will complete the lock | |
3639 | * protected section without being interrupted. So there is no | |
3640 | * real need to boost. | |
3641 | */ | |
3642 | if (unlikely(p == rq->idle)) { | |
3643 | WARN_ON(p != rq->curr); | |
3644 | WARN_ON(p->pi_blocked_on); | |
3645 | goto out_unlock; | |
3646 | } | |
3647 | ||
a8027073 | 3648 | trace_sched_pi_setprio(p, prio); |
d5f9f942 | 3649 | oldprio = p->prio; |
ff77e468 PZ |
3650 | |
3651 | if (oldprio == prio) | |
3652 | queue_flag &= ~DEQUEUE_MOVE; | |
3653 | ||
83ab0aa0 | 3654 | prev_class = p->sched_class; |
da0c1e65 | 3655 | queued = task_on_rq_queued(p); |
051a1d1a | 3656 | running = task_current(rq, p); |
da0c1e65 | 3657 | if (queued) |
ff77e468 | 3658 | dequeue_task(rq, p, queue_flag); |
0e1f3483 | 3659 | if (running) |
f3cd1c4e | 3660 | put_prev_task(rq, p); |
dd41f596 | 3661 | |
2d3d891d DF |
3662 | /* |
3663 | * Boosting condition are: | |
3664 | * 1. -rt task is running and holds mutex A | |
3665 | * --> -dl task blocks on mutex A | |
3666 | * | |
3667 | * 2. -dl task is running and holds mutex A | |
3668 | * --> -dl task blocks on mutex A and could preempt the | |
3669 | * running task | |
3670 | */ | |
3671 | if (dl_prio(prio)) { | |
466af29b ON |
3672 | struct task_struct *pi_task = rt_mutex_get_top_task(p); |
3673 | if (!dl_prio(p->normal_prio) || | |
3674 | (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { | |
2d3d891d | 3675 | p->dl.dl_boosted = 1; |
ff77e468 | 3676 | queue_flag |= ENQUEUE_REPLENISH; |
2d3d891d DF |
3677 | } else |
3678 | p->dl.dl_boosted = 0; | |
aab03e05 | 3679 | p->sched_class = &dl_sched_class; |
2d3d891d DF |
3680 | } else if (rt_prio(prio)) { |
3681 | if (dl_prio(oldprio)) | |
3682 | p->dl.dl_boosted = 0; | |
3683 | if (oldprio < prio) | |
ff77e468 | 3684 | queue_flag |= ENQUEUE_HEAD; |
dd41f596 | 3685 | p->sched_class = &rt_sched_class; |
2d3d891d DF |
3686 | } else { |
3687 | if (dl_prio(oldprio)) | |
3688 | p->dl.dl_boosted = 0; | |
746db944 BS |
3689 | if (rt_prio(oldprio)) |
3690 | p->rt.timeout = 0; | |
dd41f596 | 3691 | p->sched_class = &fair_sched_class; |
2d3d891d | 3692 | } |
dd41f596 | 3693 | |
b29739f9 IM |
3694 | p->prio = prio; |
3695 | ||
0e1f3483 HS |
3696 | if (running) |
3697 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 3698 | if (queued) |
ff77e468 | 3699 | enqueue_task(rq, p, queue_flag); |
cb469845 | 3700 | |
da7a735e | 3701 | check_class_changed(rq, p, prev_class, oldprio); |
1c4dd99b | 3702 | out_unlock: |
4c9a4bc8 | 3703 | preempt_disable(); /* avoid rq from going away on us */ |
eb580751 | 3704 | __task_rq_unlock(rq, &rf); |
4c9a4bc8 PZ |
3705 | |
3706 | balance_callback(rq); | |
3707 | preempt_enable(); | |
b29739f9 | 3708 | } |
b29739f9 | 3709 | #endif |
d50dde5a | 3710 | |
36c8b586 | 3711 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3712 | { |
da0c1e65 | 3713 | int old_prio, delta, queued; |
eb580751 | 3714 | struct rq_flags rf; |
70b97a7f | 3715 | struct rq *rq; |
1da177e4 | 3716 | |
75e45d51 | 3717 | if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) |
1da177e4 LT |
3718 | return; |
3719 | /* | |
3720 | * We have to be careful, if called from sys_setpriority(), | |
3721 | * the task might be in the middle of scheduling on another CPU. | |
3722 | */ | |
eb580751 | 3723 | rq = task_rq_lock(p, &rf); |
1da177e4 LT |
3724 | /* |
3725 | * The RT priorities are set via sched_setscheduler(), but we still | |
3726 | * allow the 'normal' nice value to be set - but as expected | |
3727 | * it wont have any effect on scheduling until the task is | |
aab03e05 | 3728 | * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: |
1da177e4 | 3729 | */ |
aab03e05 | 3730 | if (task_has_dl_policy(p) || task_has_rt_policy(p)) { |
1da177e4 LT |
3731 | p->static_prio = NICE_TO_PRIO(nice); |
3732 | goto out_unlock; | |
3733 | } | |
da0c1e65 KT |
3734 | queued = task_on_rq_queued(p); |
3735 | if (queued) | |
1de64443 | 3736 | dequeue_task(rq, p, DEQUEUE_SAVE); |
1da177e4 | 3737 | |
1da177e4 | 3738 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3739 | set_load_weight(p); |
b29739f9 IM |
3740 | old_prio = p->prio; |
3741 | p->prio = effective_prio(p); | |
3742 | delta = p->prio - old_prio; | |
1da177e4 | 3743 | |
da0c1e65 | 3744 | if (queued) { |
1de64443 | 3745 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
1da177e4 | 3746 | /* |
d5f9f942 AM |
3747 | * If the task increased its priority or is running and |
3748 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3749 | */ |
d5f9f942 | 3750 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
8875125e | 3751 | resched_curr(rq); |
1da177e4 LT |
3752 | } |
3753 | out_unlock: | |
90db6ecb | 3754 | trace_sched_update_prio(p); |
eb580751 | 3755 | task_rq_unlock(rq, p, &rf); |
1da177e4 | 3756 | } |
1da177e4 LT |
3757 | EXPORT_SYMBOL(set_user_nice); |
3758 | ||
e43379f1 MM |
3759 | /* |
3760 | * can_nice - check if a task can reduce its nice value | |
3761 | * @p: task | |
3762 | * @nice: nice value | |
3763 | */ | |
36c8b586 | 3764 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3765 | { |
024f4747 | 3766 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
7aa2c016 | 3767 | int nice_rlim = nice_to_rlimit(nice); |
48f24c4d | 3768 | |
78d7d407 | 3769 | return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || |
e43379f1 MM |
3770 | capable(CAP_SYS_NICE)); |
3771 | } | |
3772 | ||
1da177e4 LT |
3773 | #ifdef __ARCH_WANT_SYS_NICE |
3774 | ||
3775 | /* | |
3776 | * sys_nice - change the priority of the current process. | |
3777 | * @increment: priority increment | |
3778 | * | |
3779 | * sys_setpriority is a more generic, but much slower function that | |
3780 | * does similar things. | |
3781 | */ | |
5add95d4 | 3782 | SYSCALL_DEFINE1(nice, int, increment) |
1da177e4 | 3783 | { |
48f24c4d | 3784 | long nice, retval; |
1da177e4 LT |
3785 | |
3786 | /* | |
3787 | * Setpriority might change our priority at the same moment. | |
3788 | * We don't have to worry. Conceptually one call occurs first | |
3789 | * and we have a single winner. | |
3790 | */ | |
a9467fa3 | 3791 | increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); |
d0ea0268 | 3792 | nice = task_nice(current) + increment; |
1da177e4 | 3793 | |
a9467fa3 | 3794 | nice = clamp_val(nice, MIN_NICE, MAX_NICE); |
e43379f1 MM |
3795 | if (increment < 0 && !can_nice(current, nice)) |
3796 | return -EPERM; | |
3797 | ||
1da177e4 LT |
3798 | retval = security_task_setnice(current, nice); |
3799 | if (retval) | |
3800 | return retval; | |
3801 | ||
3802 | set_user_nice(current, nice); | |
3803 | return 0; | |
3804 | } | |
3805 | ||
3806 | #endif | |
3807 | ||
3808 | /** | |
3809 | * task_prio - return the priority value of a given task. | |
3810 | * @p: the task in question. | |
3811 | * | |
e69f6186 | 3812 | * Return: The priority value as seen by users in /proc. |
1da177e4 LT |
3813 | * RT tasks are offset by -200. Normal tasks are centered |
3814 | * around 0, value goes from -16 to +15. | |
3815 | */ | |
36c8b586 | 3816 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
3817 | { |
3818 | return p->prio - MAX_RT_PRIO; | |
3819 | } | |
3820 | ||
1da177e4 LT |
3821 | /** |
3822 | * idle_cpu - is a given cpu idle currently? | |
3823 | * @cpu: the processor in question. | |
e69f6186 YB |
3824 | * |
3825 | * Return: 1 if the CPU is currently idle. 0 otherwise. | |
1da177e4 LT |
3826 | */ |
3827 | int idle_cpu(int cpu) | |
3828 | { | |
908a3283 TG |
3829 | struct rq *rq = cpu_rq(cpu); |
3830 | ||
3831 | if (rq->curr != rq->idle) | |
3832 | return 0; | |
3833 | ||
3834 | if (rq->nr_running) | |
3835 | return 0; | |
3836 | ||
3837 | #ifdef CONFIG_SMP | |
3838 | if (!llist_empty(&rq->wake_list)) | |
3839 | return 0; | |
3840 | #endif | |
3841 | ||
3842 | return 1; | |
1da177e4 LT |
3843 | } |
3844 | ||
1da177e4 LT |
3845 | /** |
3846 | * idle_task - return the idle task for a given cpu. | |
3847 | * @cpu: the processor in question. | |
e69f6186 YB |
3848 | * |
3849 | * Return: The idle task for the cpu @cpu. | |
1da177e4 | 3850 | */ |
36c8b586 | 3851 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
3852 | { |
3853 | return cpu_rq(cpu)->idle; | |
3854 | } | |
3855 | ||
3856 | /** | |
3857 | * find_process_by_pid - find a process with a matching PID value. | |
3858 | * @pid: the pid in question. | |
e69f6186 YB |
3859 | * |
3860 | * The task of @pid, if found. %NULL otherwise. | |
1da177e4 | 3861 | */ |
a9957449 | 3862 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 3863 | { |
228ebcbe | 3864 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
3865 | } |
3866 | ||
aab03e05 DF |
3867 | /* |
3868 | * This function initializes the sched_dl_entity of a newly becoming | |
3869 | * SCHED_DEADLINE task. | |
3870 | * | |
3871 | * Only the static values are considered here, the actual runtime and the | |
3872 | * absolute deadline will be properly calculated when the task is enqueued | |
3873 | * for the first time with its new policy. | |
3874 | */ | |
3875 | static void | |
3876 | __setparam_dl(struct task_struct *p, const struct sched_attr *attr) | |
3877 | { | |
3878 | struct sched_dl_entity *dl_se = &p->dl; | |
3879 | ||
aab03e05 DF |
3880 | dl_se->dl_runtime = attr->sched_runtime; |
3881 | dl_se->dl_deadline = attr->sched_deadline; | |
755378a4 | 3882 | dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; |
aab03e05 | 3883 | dl_se->flags = attr->sched_flags; |
332ac17e | 3884 | dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); |
40767b0d PZ |
3885 | |
3886 | /* | |
3887 | * Changing the parameters of a task is 'tricky' and we're not doing | |
3888 | * the correct thing -- also see task_dead_dl() and switched_from_dl(). | |
3889 | * | |
3890 | * What we SHOULD do is delay the bandwidth release until the 0-lag | |
3891 | * point. This would include retaining the task_struct until that time | |
3892 | * and change dl_overflow() to not immediately decrement the current | |
3893 | * amount. | |
3894 | * | |
3895 | * Instead we retain the current runtime/deadline and let the new | |
3896 | * parameters take effect after the current reservation period lapses. | |
3897 | * This is safe (albeit pessimistic) because the 0-lag point is always | |
3898 | * before the current scheduling deadline. | |
3899 | * | |
3900 | * We can still have temporary overloads because we do not delay the | |
3901 | * change in bandwidth until that time; so admission control is | |
3902 | * not on the safe side. It does however guarantee tasks will never | |
3903 | * consume more than promised. | |
3904 | */ | |
aab03e05 DF |
3905 | } |
3906 | ||
c13db6b1 SR |
3907 | /* |
3908 | * sched_setparam() passes in -1 for its policy, to let the functions | |
3909 | * it calls know not to change it. | |
3910 | */ | |
3911 | #define SETPARAM_POLICY -1 | |
3912 | ||
c365c292 TG |
3913 | static void __setscheduler_params(struct task_struct *p, |
3914 | const struct sched_attr *attr) | |
1da177e4 | 3915 | { |
d50dde5a DF |
3916 | int policy = attr->sched_policy; |
3917 | ||
c13db6b1 | 3918 | if (policy == SETPARAM_POLICY) |
39fd8fd2 PZ |
3919 | policy = p->policy; |
3920 | ||
1da177e4 | 3921 | p->policy = policy; |
d50dde5a | 3922 | |
aab03e05 DF |
3923 | if (dl_policy(policy)) |
3924 | __setparam_dl(p, attr); | |
39fd8fd2 | 3925 | else if (fair_policy(policy)) |
d50dde5a DF |
3926 | p->static_prio = NICE_TO_PRIO(attr->sched_nice); |
3927 | ||
39fd8fd2 PZ |
3928 | /* |
3929 | * __sched_setscheduler() ensures attr->sched_priority == 0 when | |
3930 | * !rt_policy. Always setting this ensures that things like | |
3931 | * getparam()/getattr() don't report silly values for !rt tasks. | |
3932 | */ | |
3933 | p->rt_priority = attr->sched_priority; | |
383afd09 | 3934 | p->normal_prio = normal_prio(p); |
c365c292 TG |
3935 | set_load_weight(p); |
3936 | } | |
39fd8fd2 | 3937 | |
c365c292 TG |
3938 | /* Actually do priority change: must hold pi & rq lock. */ |
3939 | static void __setscheduler(struct rq *rq, struct task_struct *p, | |
0782e63b | 3940 | const struct sched_attr *attr, bool keep_boost) |
c365c292 TG |
3941 | { |
3942 | __setscheduler_params(p, attr); | |
d50dde5a | 3943 | |
383afd09 | 3944 | /* |
0782e63b TG |
3945 | * Keep a potential priority boosting if called from |
3946 | * sched_setscheduler(). | |
383afd09 | 3947 | */ |
0782e63b TG |
3948 | if (keep_boost) |
3949 | p->prio = rt_mutex_get_effective_prio(p, normal_prio(p)); | |
3950 | else | |
3951 | p->prio = normal_prio(p); | |
383afd09 | 3952 | |
aab03e05 DF |
3953 | if (dl_prio(p->prio)) |
3954 | p->sched_class = &dl_sched_class; | |
3955 | else if (rt_prio(p->prio)) | |
ffd44db5 PZ |
3956 | p->sched_class = &rt_sched_class; |
3957 | else | |
3958 | p->sched_class = &fair_sched_class; | |
90db6ecb JD |
3959 | |
3960 | trace_sched_update_prio(p); | |
1da177e4 | 3961 | } |
aab03e05 DF |
3962 | |
3963 | static void | |
3964 | __getparam_dl(struct task_struct *p, struct sched_attr *attr) | |
3965 | { | |
3966 | struct sched_dl_entity *dl_se = &p->dl; | |
3967 | ||
3968 | attr->sched_priority = p->rt_priority; | |
3969 | attr->sched_runtime = dl_se->dl_runtime; | |
3970 | attr->sched_deadline = dl_se->dl_deadline; | |
755378a4 | 3971 | attr->sched_period = dl_se->dl_period; |
aab03e05 DF |
3972 | attr->sched_flags = dl_se->flags; |
3973 | } | |
3974 | ||
3975 | /* | |
3976 | * This function validates the new parameters of a -deadline task. | |
3977 | * We ask for the deadline not being zero, and greater or equal | |
755378a4 | 3978 | * than the runtime, as well as the period of being zero or |
332ac17e | 3979 | * greater than deadline. Furthermore, we have to be sure that |
b0827819 JL |
3980 | * user parameters are above the internal resolution of 1us (we |
3981 | * check sched_runtime only since it is always the smaller one) and | |
3982 | * below 2^63 ns (we have to check both sched_deadline and | |
3983 | * sched_period, as the latter can be zero). | |
aab03e05 DF |
3984 | */ |
3985 | static bool | |
3986 | __checkparam_dl(const struct sched_attr *attr) | |
3987 | { | |
b0827819 JL |
3988 | /* deadline != 0 */ |
3989 | if (attr->sched_deadline == 0) | |
3990 | return false; | |
3991 | ||
3992 | /* | |
3993 | * Since we truncate DL_SCALE bits, make sure we're at least | |
3994 | * that big. | |
3995 | */ | |
3996 | if (attr->sched_runtime < (1ULL << DL_SCALE)) | |
3997 | return false; | |
3998 | ||
3999 | /* | |
4000 | * Since we use the MSB for wrap-around and sign issues, make | |
4001 | * sure it's not set (mind that period can be equal to zero). | |
4002 | */ | |
4003 | if (attr->sched_deadline & (1ULL << 63) || | |
4004 | attr->sched_period & (1ULL << 63)) | |
4005 | return false; | |
4006 | ||
4007 | /* runtime <= deadline <= period (if period != 0) */ | |
4008 | if ((attr->sched_period != 0 && | |
4009 | attr->sched_period < attr->sched_deadline) || | |
4010 | attr->sched_deadline < attr->sched_runtime) | |
4011 | return false; | |
4012 | ||
4013 | return true; | |
aab03e05 DF |
4014 | } |
4015 | ||
c69e8d9c DH |
4016 | /* |
4017 | * check the target process has a UID that matches the current process's | |
4018 | */ | |
4019 | static bool check_same_owner(struct task_struct *p) | |
4020 | { | |
4021 | const struct cred *cred = current_cred(), *pcred; | |
4022 | bool match; | |
4023 | ||
4024 | rcu_read_lock(); | |
4025 | pcred = __task_cred(p); | |
9c806aa0 EB |
4026 | match = (uid_eq(cred->euid, pcred->euid) || |
4027 | uid_eq(cred->euid, pcred->uid)); | |
c69e8d9c DH |
4028 | rcu_read_unlock(); |
4029 | return match; | |
4030 | } | |
4031 | ||
75381608 WL |
4032 | static bool dl_param_changed(struct task_struct *p, |
4033 | const struct sched_attr *attr) | |
4034 | { | |
4035 | struct sched_dl_entity *dl_se = &p->dl; | |
4036 | ||
4037 | if (dl_se->dl_runtime != attr->sched_runtime || | |
4038 | dl_se->dl_deadline != attr->sched_deadline || | |
4039 | dl_se->dl_period != attr->sched_period || | |
4040 | dl_se->flags != attr->sched_flags) | |
4041 | return true; | |
4042 | ||
4043 | return false; | |
4044 | } | |
4045 | ||
d50dde5a DF |
4046 | static int __sched_setscheduler(struct task_struct *p, |
4047 | const struct sched_attr *attr, | |
dbc7f069 | 4048 | bool user, bool pi) |
1da177e4 | 4049 | { |
383afd09 SR |
4050 | int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : |
4051 | MAX_RT_PRIO - 1 - attr->sched_priority; | |
da0c1e65 | 4052 | int retval, oldprio, oldpolicy = -1, queued, running; |
0782e63b | 4053 | int new_effective_prio, policy = attr->sched_policy; |
83ab0aa0 | 4054 | const struct sched_class *prev_class; |
eb580751 | 4055 | struct rq_flags rf; |
ca94c442 | 4056 | int reset_on_fork; |
ff77e468 | 4057 | int queue_flags = DEQUEUE_SAVE | DEQUEUE_MOVE; |
eb580751 | 4058 | struct rq *rq; |
1da177e4 | 4059 | |
66e5393a SR |
4060 | /* may grab non-irq protected spin_locks */ |
4061 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
4062 | recheck: |
4063 | /* double check policy once rq lock held */ | |
ca94c442 LP |
4064 | if (policy < 0) { |
4065 | reset_on_fork = p->sched_reset_on_fork; | |
1da177e4 | 4066 | policy = oldpolicy = p->policy; |
ca94c442 | 4067 | } else { |
7479f3c9 | 4068 | reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); |
ca94c442 | 4069 | |
20f9cd2a | 4070 | if (!valid_policy(policy)) |
ca94c442 LP |
4071 | return -EINVAL; |
4072 | } | |
4073 | ||
7479f3c9 PZ |
4074 | if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) |
4075 | return -EINVAL; | |
4076 | ||
1da177e4 LT |
4077 | /* |
4078 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
4079 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
4080 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 | 4081 | */ |
0bb040a4 | 4082 | if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || |
d50dde5a | 4083 | (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 4084 | return -EINVAL; |
aab03e05 DF |
4085 | if ((dl_policy(policy) && !__checkparam_dl(attr)) || |
4086 | (rt_policy(policy) != (attr->sched_priority != 0))) | |
1da177e4 LT |
4087 | return -EINVAL; |
4088 | ||
37e4ab3f OC |
4089 | /* |
4090 | * Allow unprivileged RT tasks to decrease priority: | |
4091 | */ | |
961ccddd | 4092 | if (user && !capable(CAP_SYS_NICE)) { |
d50dde5a | 4093 | if (fair_policy(policy)) { |
d0ea0268 | 4094 | if (attr->sched_nice < task_nice(p) && |
eaad4513 | 4095 | !can_nice(p, attr->sched_nice)) |
d50dde5a DF |
4096 | return -EPERM; |
4097 | } | |
4098 | ||
e05606d3 | 4099 | if (rt_policy(policy)) { |
a44702e8 ON |
4100 | unsigned long rlim_rtprio = |
4101 | task_rlimit(p, RLIMIT_RTPRIO); | |
8dc3e909 ON |
4102 | |
4103 | /* can't set/change the rt policy */ | |
4104 | if (policy != p->policy && !rlim_rtprio) | |
4105 | return -EPERM; | |
4106 | ||
4107 | /* can't increase priority */ | |
d50dde5a DF |
4108 | if (attr->sched_priority > p->rt_priority && |
4109 | attr->sched_priority > rlim_rtprio) | |
8dc3e909 ON |
4110 | return -EPERM; |
4111 | } | |
c02aa73b | 4112 | |
d44753b8 JL |
4113 | /* |
4114 | * Can't set/change SCHED_DEADLINE policy at all for now | |
4115 | * (safest behavior); in the future we would like to allow | |
4116 | * unprivileged DL tasks to increase their relative deadline | |
4117 | * or reduce their runtime (both ways reducing utilization) | |
4118 | */ | |
4119 | if (dl_policy(policy)) | |
4120 | return -EPERM; | |
4121 | ||
dd41f596 | 4122 | /* |
c02aa73b DH |
4123 | * Treat SCHED_IDLE as nice 20. Only allow a switch to |
4124 | * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. | |
dd41f596 | 4125 | */ |
20f9cd2a | 4126 | if (idle_policy(p->policy) && !idle_policy(policy)) { |
d0ea0268 | 4127 | if (!can_nice(p, task_nice(p))) |
c02aa73b DH |
4128 | return -EPERM; |
4129 | } | |
5fe1d75f | 4130 | |
37e4ab3f | 4131 | /* can't change other user's priorities */ |
c69e8d9c | 4132 | if (!check_same_owner(p)) |
37e4ab3f | 4133 | return -EPERM; |
ca94c442 LP |
4134 | |
4135 | /* Normal users shall not reset the sched_reset_on_fork flag */ | |
4136 | if (p->sched_reset_on_fork && !reset_on_fork) | |
4137 | return -EPERM; | |
37e4ab3f | 4138 | } |
1da177e4 | 4139 | |
725aad24 | 4140 | if (user) { |
b0ae1981 | 4141 | retval = security_task_setscheduler(p); |
725aad24 JF |
4142 | if (retval) |
4143 | return retval; | |
4144 | } | |
4145 | ||
b29739f9 IM |
4146 | /* |
4147 | * make sure no PI-waiters arrive (or leave) while we are | |
4148 | * changing the priority of the task: | |
0122ec5b | 4149 | * |
25985edc | 4150 | * To be able to change p->policy safely, the appropriate |
1da177e4 LT |
4151 | * runqueue lock must be held. |
4152 | */ | |
eb580751 | 4153 | rq = task_rq_lock(p, &rf); |
dc61b1d6 | 4154 | |
34f971f6 PZ |
4155 | /* |
4156 | * Changing the policy of the stop threads its a very bad idea | |
4157 | */ | |
4158 | if (p == rq->stop) { | |
eb580751 | 4159 | task_rq_unlock(rq, p, &rf); |
34f971f6 PZ |
4160 | return -EINVAL; |
4161 | } | |
4162 | ||
a51e9198 | 4163 | /* |
d6b1e911 TG |
4164 | * If not changing anything there's no need to proceed further, |
4165 | * but store a possible modification of reset_on_fork. | |
a51e9198 | 4166 | */ |
d50dde5a | 4167 | if (unlikely(policy == p->policy)) { |
d0ea0268 | 4168 | if (fair_policy(policy) && attr->sched_nice != task_nice(p)) |
d50dde5a DF |
4169 | goto change; |
4170 | if (rt_policy(policy) && attr->sched_priority != p->rt_priority) | |
4171 | goto change; | |
75381608 | 4172 | if (dl_policy(policy) && dl_param_changed(p, attr)) |
aab03e05 | 4173 | goto change; |
d50dde5a | 4174 | |
d6b1e911 | 4175 | p->sched_reset_on_fork = reset_on_fork; |
eb580751 | 4176 | task_rq_unlock(rq, p, &rf); |
a51e9198 DF |
4177 | return 0; |
4178 | } | |
d50dde5a | 4179 | change: |
a51e9198 | 4180 | |
dc61b1d6 | 4181 | if (user) { |
332ac17e | 4182 | #ifdef CONFIG_RT_GROUP_SCHED |
dc61b1d6 PZ |
4183 | /* |
4184 | * Do not allow realtime tasks into groups that have no runtime | |
4185 | * assigned. | |
4186 | */ | |
4187 | if (rt_bandwidth_enabled() && rt_policy(policy) && | |
f4493771 MG |
4188 | task_group(p)->rt_bandwidth.rt_runtime == 0 && |
4189 | !task_group_is_autogroup(task_group(p))) { | |
eb580751 | 4190 | task_rq_unlock(rq, p, &rf); |
dc61b1d6 PZ |
4191 | return -EPERM; |
4192 | } | |
dc61b1d6 | 4193 | #endif |
332ac17e DF |
4194 | #ifdef CONFIG_SMP |
4195 | if (dl_bandwidth_enabled() && dl_policy(policy)) { | |
4196 | cpumask_t *span = rq->rd->span; | |
332ac17e DF |
4197 | |
4198 | /* | |
4199 | * Don't allow tasks with an affinity mask smaller than | |
4200 | * the entire root_domain to become SCHED_DEADLINE. We | |
4201 | * will also fail if there's no bandwidth available. | |
4202 | */ | |
e4099a5e PZ |
4203 | if (!cpumask_subset(span, &p->cpus_allowed) || |
4204 | rq->rd->dl_bw.bw == 0) { | |
eb580751 | 4205 | task_rq_unlock(rq, p, &rf); |
332ac17e DF |
4206 | return -EPERM; |
4207 | } | |
4208 | } | |
4209 | #endif | |
4210 | } | |
dc61b1d6 | 4211 | |
1da177e4 LT |
4212 | /* recheck policy now with rq lock held */ |
4213 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4214 | policy = oldpolicy = -1; | |
eb580751 | 4215 | task_rq_unlock(rq, p, &rf); |
1da177e4 LT |
4216 | goto recheck; |
4217 | } | |
332ac17e DF |
4218 | |
4219 | /* | |
4220 | * If setscheduling to SCHED_DEADLINE (or changing the parameters | |
4221 | * of a SCHED_DEADLINE task) we need to check if enough bandwidth | |
4222 | * is available. | |
4223 | */ | |
e4099a5e | 4224 | if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { |
eb580751 | 4225 | task_rq_unlock(rq, p, &rf); |
332ac17e DF |
4226 | return -EBUSY; |
4227 | } | |
4228 | ||
c365c292 TG |
4229 | p->sched_reset_on_fork = reset_on_fork; |
4230 | oldprio = p->prio; | |
4231 | ||
dbc7f069 PZ |
4232 | if (pi) { |
4233 | /* | |
4234 | * Take priority boosted tasks into account. If the new | |
4235 | * effective priority is unchanged, we just store the new | |
4236 | * normal parameters and do not touch the scheduler class and | |
4237 | * the runqueue. This will be done when the task deboost | |
4238 | * itself. | |
4239 | */ | |
4240 | new_effective_prio = rt_mutex_get_effective_prio(p, newprio); | |
ff77e468 PZ |
4241 | if (new_effective_prio == oldprio) |
4242 | queue_flags &= ~DEQUEUE_MOVE; | |
c365c292 TG |
4243 | } |
4244 | ||
da0c1e65 | 4245 | queued = task_on_rq_queued(p); |
051a1d1a | 4246 | running = task_current(rq, p); |
da0c1e65 | 4247 | if (queued) |
ff77e468 | 4248 | dequeue_task(rq, p, queue_flags); |
0e1f3483 | 4249 | if (running) |
f3cd1c4e | 4250 | put_prev_task(rq, p); |
f6b53205 | 4251 | |
83ab0aa0 | 4252 | prev_class = p->sched_class; |
dbc7f069 | 4253 | __setscheduler(rq, p, attr, pi); |
f6b53205 | 4254 | |
0e1f3483 HS |
4255 | if (running) |
4256 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 4257 | if (queued) { |
81a44c54 TG |
4258 | /* |
4259 | * We enqueue to tail when the priority of a task is | |
4260 | * increased (user space view). | |
4261 | */ | |
ff77e468 PZ |
4262 | if (oldprio < p->prio) |
4263 | queue_flags |= ENQUEUE_HEAD; | |
1de64443 | 4264 | |
ff77e468 | 4265 | enqueue_task(rq, p, queue_flags); |
81a44c54 | 4266 | } |
cb469845 | 4267 | |
da7a735e | 4268 | check_class_changed(rq, p, prev_class, oldprio); |
4c9a4bc8 | 4269 | preempt_disable(); /* avoid rq from going away on us */ |
eb580751 | 4270 | task_rq_unlock(rq, p, &rf); |
b29739f9 | 4271 | |
dbc7f069 PZ |
4272 | if (pi) |
4273 | rt_mutex_adjust_pi(p); | |
95e02ca9 | 4274 | |
4c9a4bc8 PZ |
4275 | /* |
4276 | * Run balance callbacks after we've adjusted the PI chain. | |
4277 | */ | |
4278 | balance_callback(rq); | |
4279 | preempt_enable(); | |
95e02ca9 | 4280 | |
1da177e4 LT |
4281 | return 0; |
4282 | } | |
961ccddd | 4283 | |
7479f3c9 PZ |
4284 | static int _sched_setscheduler(struct task_struct *p, int policy, |
4285 | const struct sched_param *param, bool check) | |
4286 | { | |
4287 | struct sched_attr attr = { | |
4288 | .sched_policy = policy, | |
4289 | .sched_priority = param->sched_priority, | |
4290 | .sched_nice = PRIO_TO_NICE(p->static_prio), | |
4291 | }; | |
4292 | ||
c13db6b1 SR |
4293 | /* Fixup the legacy SCHED_RESET_ON_FORK hack. */ |
4294 | if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) { | |
7479f3c9 PZ |
4295 | attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; |
4296 | policy &= ~SCHED_RESET_ON_FORK; | |
4297 | attr.sched_policy = policy; | |
4298 | } | |
4299 | ||
dbc7f069 | 4300 | return __sched_setscheduler(p, &attr, check, true); |
7479f3c9 | 4301 | } |
961ccddd RR |
4302 | /** |
4303 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. | |
4304 | * @p: the task in question. | |
4305 | * @policy: new policy. | |
4306 | * @param: structure containing the new RT priority. | |
4307 | * | |
e69f6186 YB |
4308 | * Return: 0 on success. An error code otherwise. |
4309 | * | |
961ccddd RR |
4310 | * NOTE that the task may be already dead. |
4311 | */ | |
4312 | int sched_setscheduler(struct task_struct *p, int policy, | |
fe7de49f | 4313 | const struct sched_param *param) |
961ccddd | 4314 | { |
7479f3c9 | 4315 | return _sched_setscheduler(p, policy, param, true); |
961ccddd | 4316 | } |
1da177e4 LT |
4317 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
4318 | ||
d50dde5a DF |
4319 | int sched_setattr(struct task_struct *p, const struct sched_attr *attr) |
4320 | { | |
dbc7f069 | 4321 | return __sched_setscheduler(p, attr, true, true); |
d50dde5a DF |
4322 | } |
4323 | EXPORT_SYMBOL_GPL(sched_setattr); | |
4324 | ||
961ccddd RR |
4325 | /** |
4326 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. | |
4327 | * @p: the task in question. | |
4328 | * @policy: new policy. | |
4329 | * @param: structure containing the new RT priority. | |
4330 | * | |
4331 | * Just like sched_setscheduler, only don't bother checking if the | |
4332 | * current context has permission. For example, this is needed in | |
4333 | * stop_machine(): we create temporary high priority worker threads, | |
4334 | * but our caller might not have that capability. | |
e69f6186 YB |
4335 | * |
4336 | * Return: 0 on success. An error code otherwise. | |
961ccddd RR |
4337 | */ |
4338 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, | |
fe7de49f | 4339 | const struct sched_param *param) |
961ccddd | 4340 | { |
7479f3c9 | 4341 | return _sched_setscheduler(p, policy, param, false); |
961ccddd | 4342 | } |
84778472 | 4343 | EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck); |
961ccddd | 4344 | |
95cdf3b7 IM |
4345 | static int |
4346 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4347 | { |
1da177e4 LT |
4348 | struct sched_param lparam; |
4349 | struct task_struct *p; | |
36c8b586 | 4350 | int retval; |
1da177e4 LT |
4351 | |
4352 | if (!param || pid < 0) | |
4353 | return -EINVAL; | |
4354 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4355 | return -EFAULT; | |
5fe1d75f ON |
4356 | |
4357 | rcu_read_lock(); | |
4358 | retval = -ESRCH; | |
1da177e4 | 4359 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4360 | if (p != NULL) |
4361 | retval = sched_setscheduler(p, policy, &lparam); | |
4362 | rcu_read_unlock(); | |
36c8b586 | 4363 | |
1da177e4 LT |
4364 | return retval; |
4365 | } | |
4366 | ||
d50dde5a DF |
4367 | /* |
4368 | * Mimics kernel/events/core.c perf_copy_attr(). | |
4369 | */ | |
4370 | static int sched_copy_attr(struct sched_attr __user *uattr, | |
4371 | struct sched_attr *attr) | |
4372 | { | |
4373 | u32 size; | |
4374 | int ret; | |
4375 | ||
4376 | if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) | |
4377 | return -EFAULT; | |
4378 | ||
4379 | /* | |
4380 | * zero the full structure, so that a short copy will be nice. | |
4381 | */ | |
4382 | memset(attr, 0, sizeof(*attr)); | |
4383 | ||
4384 | ret = get_user(size, &uattr->size); | |
4385 | if (ret) | |
4386 | return ret; | |
4387 | ||
4388 | if (size > PAGE_SIZE) /* silly large */ | |
4389 | goto err_size; | |
4390 | ||
4391 | if (!size) /* abi compat */ | |
4392 | size = SCHED_ATTR_SIZE_VER0; | |
4393 | ||
4394 | if (size < SCHED_ATTR_SIZE_VER0) | |
4395 | goto err_size; | |
4396 | ||
4397 | /* | |
4398 | * If we're handed a bigger struct than we know of, | |
4399 | * ensure all the unknown bits are 0 - i.e. new | |
4400 | * user-space does not rely on any kernel feature | |
4401 | * extensions we dont know about yet. | |
4402 | */ | |
4403 | if (size > sizeof(*attr)) { | |
4404 | unsigned char __user *addr; | |
4405 | unsigned char __user *end; | |
4406 | unsigned char val; | |
4407 | ||
4408 | addr = (void __user *)uattr + sizeof(*attr); | |
4409 | end = (void __user *)uattr + size; | |
4410 | ||
4411 | for (; addr < end; addr++) { | |
4412 | ret = get_user(val, addr); | |
4413 | if (ret) | |
4414 | return ret; | |
4415 | if (val) | |
4416 | goto err_size; | |
4417 | } | |
4418 | size = sizeof(*attr); | |
4419 | } | |
4420 | ||
4421 | ret = copy_from_user(attr, uattr, size); | |
4422 | if (ret) | |
4423 | return -EFAULT; | |
4424 | ||
4425 | /* | |
4426 | * XXX: do we want to be lenient like existing syscalls; or do we want | |
4427 | * to be strict and return an error on out-of-bounds values? | |
4428 | */ | |
75e45d51 | 4429 | attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); |
d50dde5a | 4430 | |
e78c7bca | 4431 | return 0; |
d50dde5a DF |
4432 | |
4433 | err_size: | |
4434 | put_user(sizeof(*attr), &uattr->size); | |
e78c7bca | 4435 | return -E2BIG; |
d50dde5a DF |
4436 | } |
4437 | ||
1da177e4 LT |
4438 | /** |
4439 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4440 | * @pid: the pid in question. | |
4441 | * @policy: new policy. | |
4442 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
4443 | * |
4444 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4445 | */ |
5add95d4 HC |
4446 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
4447 | struct sched_param __user *, param) | |
1da177e4 | 4448 | { |
c21761f1 JB |
4449 | /* negative values for policy are not valid */ |
4450 | if (policy < 0) | |
4451 | return -EINVAL; | |
4452 | ||
1da177e4 LT |
4453 | return do_sched_setscheduler(pid, policy, param); |
4454 | } | |
4455 | ||
4456 | /** | |
4457 | * sys_sched_setparam - set/change the RT priority of a thread | |
4458 | * @pid: the pid in question. | |
4459 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
4460 | * |
4461 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4462 | */ |
5add95d4 | 4463 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 | 4464 | { |
c13db6b1 | 4465 | return do_sched_setscheduler(pid, SETPARAM_POLICY, param); |
1da177e4 LT |
4466 | } |
4467 | ||
d50dde5a DF |
4468 | /** |
4469 | * sys_sched_setattr - same as above, but with extended sched_attr | |
4470 | * @pid: the pid in question. | |
5778fccf | 4471 | * @uattr: structure containing the extended parameters. |
db66d756 | 4472 | * @flags: for future extension. |
d50dde5a | 4473 | */ |
6d35ab48 PZ |
4474 | SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, |
4475 | unsigned int, flags) | |
d50dde5a DF |
4476 | { |
4477 | struct sched_attr attr; | |
4478 | struct task_struct *p; | |
4479 | int retval; | |
4480 | ||
6d35ab48 | 4481 | if (!uattr || pid < 0 || flags) |
d50dde5a DF |
4482 | return -EINVAL; |
4483 | ||
143cf23d MK |
4484 | retval = sched_copy_attr(uattr, &attr); |
4485 | if (retval) | |
4486 | return retval; | |
d50dde5a | 4487 | |
b14ed2c2 | 4488 | if ((int)attr.sched_policy < 0) |
dbdb2275 | 4489 | return -EINVAL; |
d50dde5a DF |
4490 | |
4491 | rcu_read_lock(); | |
4492 | retval = -ESRCH; | |
4493 | p = find_process_by_pid(pid); | |
4494 | if (p != NULL) | |
4495 | retval = sched_setattr(p, &attr); | |
4496 | rcu_read_unlock(); | |
4497 | ||
4498 | return retval; | |
4499 | } | |
4500 | ||
1da177e4 LT |
4501 | /** |
4502 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4503 | * @pid: the pid in question. | |
e69f6186 YB |
4504 | * |
4505 | * Return: On success, the policy of the thread. Otherwise, a negative error | |
4506 | * code. | |
1da177e4 | 4507 | */ |
5add95d4 | 4508 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
1da177e4 | 4509 | { |
36c8b586 | 4510 | struct task_struct *p; |
3a5c359a | 4511 | int retval; |
1da177e4 LT |
4512 | |
4513 | if (pid < 0) | |
3a5c359a | 4514 | return -EINVAL; |
1da177e4 LT |
4515 | |
4516 | retval = -ESRCH; | |
5fe85be0 | 4517 | rcu_read_lock(); |
1da177e4 LT |
4518 | p = find_process_by_pid(pid); |
4519 | if (p) { | |
4520 | retval = security_task_getscheduler(p); | |
4521 | if (!retval) | |
ca94c442 LP |
4522 | retval = p->policy |
4523 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); | |
1da177e4 | 4524 | } |
5fe85be0 | 4525 | rcu_read_unlock(); |
1da177e4 LT |
4526 | return retval; |
4527 | } | |
4528 | ||
4529 | /** | |
ca94c442 | 4530 | * sys_sched_getparam - get the RT priority of a thread |
1da177e4 LT |
4531 | * @pid: the pid in question. |
4532 | * @param: structure containing the RT priority. | |
e69f6186 YB |
4533 | * |
4534 | * Return: On success, 0 and the RT priority is in @param. Otherwise, an error | |
4535 | * code. | |
1da177e4 | 4536 | */ |
5add95d4 | 4537 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 | 4538 | { |
ce5f7f82 | 4539 | struct sched_param lp = { .sched_priority = 0 }; |
36c8b586 | 4540 | struct task_struct *p; |
3a5c359a | 4541 | int retval; |
1da177e4 LT |
4542 | |
4543 | if (!param || pid < 0) | |
3a5c359a | 4544 | return -EINVAL; |
1da177e4 | 4545 | |
5fe85be0 | 4546 | rcu_read_lock(); |
1da177e4 LT |
4547 | p = find_process_by_pid(pid); |
4548 | retval = -ESRCH; | |
4549 | if (!p) | |
4550 | goto out_unlock; | |
4551 | ||
4552 | retval = security_task_getscheduler(p); | |
4553 | if (retval) | |
4554 | goto out_unlock; | |
4555 | ||
ce5f7f82 PZ |
4556 | if (task_has_rt_policy(p)) |
4557 | lp.sched_priority = p->rt_priority; | |
5fe85be0 | 4558 | rcu_read_unlock(); |
1da177e4 LT |
4559 | |
4560 | /* | |
4561 | * This one might sleep, we cannot do it with a spinlock held ... | |
4562 | */ | |
4563 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4564 | ||
1da177e4 LT |
4565 | return retval; |
4566 | ||
4567 | out_unlock: | |
5fe85be0 | 4568 | rcu_read_unlock(); |
1da177e4 LT |
4569 | return retval; |
4570 | } | |
4571 | ||
d50dde5a DF |
4572 | static int sched_read_attr(struct sched_attr __user *uattr, |
4573 | struct sched_attr *attr, | |
4574 | unsigned int usize) | |
4575 | { | |
4576 | int ret; | |
4577 | ||
4578 | if (!access_ok(VERIFY_WRITE, uattr, usize)) | |
4579 | return -EFAULT; | |
4580 | ||
4581 | /* | |
4582 | * If we're handed a smaller struct than we know of, | |
4583 | * ensure all the unknown bits are 0 - i.e. old | |
4584 | * user-space does not get uncomplete information. | |
4585 | */ | |
4586 | if (usize < sizeof(*attr)) { | |
4587 | unsigned char *addr; | |
4588 | unsigned char *end; | |
4589 | ||
4590 | addr = (void *)attr + usize; | |
4591 | end = (void *)attr + sizeof(*attr); | |
4592 | ||
4593 | for (; addr < end; addr++) { | |
4594 | if (*addr) | |
22400674 | 4595 | return -EFBIG; |
d50dde5a DF |
4596 | } |
4597 | ||
4598 | attr->size = usize; | |
4599 | } | |
4600 | ||
4efbc454 | 4601 | ret = copy_to_user(uattr, attr, attr->size); |
d50dde5a DF |
4602 | if (ret) |
4603 | return -EFAULT; | |
4604 | ||
22400674 | 4605 | return 0; |
d50dde5a DF |
4606 | } |
4607 | ||
4608 | /** | |
aab03e05 | 4609 | * sys_sched_getattr - similar to sched_getparam, but with sched_attr |
d50dde5a | 4610 | * @pid: the pid in question. |
5778fccf | 4611 | * @uattr: structure containing the extended parameters. |
d50dde5a | 4612 | * @size: sizeof(attr) for fwd/bwd comp. |
db66d756 | 4613 | * @flags: for future extension. |
d50dde5a | 4614 | */ |
6d35ab48 PZ |
4615 | SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, |
4616 | unsigned int, size, unsigned int, flags) | |
d50dde5a DF |
4617 | { |
4618 | struct sched_attr attr = { | |
4619 | .size = sizeof(struct sched_attr), | |
4620 | }; | |
4621 | struct task_struct *p; | |
4622 | int retval; | |
4623 | ||
4624 | if (!uattr || pid < 0 || size > PAGE_SIZE || | |
6d35ab48 | 4625 | size < SCHED_ATTR_SIZE_VER0 || flags) |
d50dde5a DF |
4626 | return -EINVAL; |
4627 | ||
4628 | rcu_read_lock(); | |
4629 | p = find_process_by_pid(pid); | |
4630 | retval = -ESRCH; | |
4631 | if (!p) | |
4632 | goto out_unlock; | |
4633 | ||
4634 | retval = security_task_getscheduler(p); | |
4635 | if (retval) | |
4636 | goto out_unlock; | |
4637 | ||
4638 | attr.sched_policy = p->policy; | |
7479f3c9 PZ |
4639 | if (p->sched_reset_on_fork) |
4640 | attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; | |
aab03e05 DF |
4641 | if (task_has_dl_policy(p)) |
4642 | __getparam_dl(p, &attr); | |
4643 | else if (task_has_rt_policy(p)) | |
d50dde5a DF |
4644 | attr.sched_priority = p->rt_priority; |
4645 | else | |
d0ea0268 | 4646 | attr.sched_nice = task_nice(p); |
d50dde5a DF |
4647 | |
4648 | rcu_read_unlock(); | |
4649 | ||
4650 | retval = sched_read_attr(uattr, &attr, size); | |
4651 | return retval; | |
4652 | ||
4653 | out_unlock: | |
4654 | rcu_read_unlock(); | |
4655 | return retval; | |
4656 | } | |
4657 | ||
96f874e2 | 4658 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
1da177e4 | 4659 | { |
5a16f3d3 | 4660 | cpumask_var_t cpus_allowed, new_mask; |
36c8b586 IM |
4661 | struct task_struct *p; |
4662 | int retval; | |
1da177e4 | 4663 | |
23f5d142 | 4664 | rcu_read_lock(); |
1da177e4 LT |
4665 | |
4666 | p = find_process_by_pid(pid); | |
4667 | if (!p) { | |
23f5d142 | 4668 | rcu_read_unlock(); |
1da177e4 LT |
4669 | return -ESRCH; |
4670 | } | |
4671 | ||
23f5d142 | 4672 | /* Prevent p going away */ |
1da177e4 | 4673 | get_task_struct(p); |
23f5d142 | 4674 | rcu_read_unlock(); |
1da177e4 | 4675 | |
14a40ffc TH |
4676 | if (p->flags & PF_NO_SETAFFINITY) { |
4677 | retval = -EINVAL; | |
4678 | goto out_put_task; | |
4679 | } | |
5a16f3d3 RR |
4680 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
4681 | retval = -ENOMEM; | |
4682 | goto out_put_task; | |
4683 | } | |
4684 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { | |
4685 | retval = -ENOMEM; | |
4686 | goto out_free_cpus_allowed; | |
4687 | } | |
1da177e4 | 4688 | retval = -EPERM; |
4c44aaaf EB |
4689 | if (!check_same_owner(p)) { |
4690 | rcu_read_lock(); | |
4691 | if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { | |
4692 | rcu_read_unlock(); | |
16303ab2 | 4693 | goto out_free_new_mask; |
4c44aaaf EB |
4694 | } |
4695 | rcu_read_unlock(); | |
4696 | } | |
1da177e4 | 4697 | |
b0ae1981 | 4698 | retval = security_task_setscheduler(p); |
e7834f8f | 4699 | if (retval) |
16303ab2 | 4700 | goto out_free_new_mask; |
e7834f8f | 4701 | |
e4099a5e PZ |
4702 | |
4703 | cpuset_cpus_allowed(p, cpus_allowed); | |
4704 | cpumask_and(new_mask, in_mask, cpus_allowed); | |
4705 | ||
332ac17e DF |
4706 | /* |
4707 | * Since bandwidth control happens on root_domain basis, | |
4708 | * if admission test is enabled, we only admit -deadline | |
4709 | * tasks allowed to run on all the CPUs in the task's | |
4710 | * root_domain. | |
4711 | */ | |
4712 | #ifdef CONFIG_SMP | |
f1e3a093 KT |
4713 | if (task_has_dl_policy(p) && dl_bandwidth_enabled()) { |
4714 | rcu_read_lock(); | |
4715 | if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) { | |
332ac17e | 4716 | retval = -EBUSY; |
f1e3a093 | 4717 | rcu_read_unlock(); |
16303ab2 | 4718 | goto out_free_new_mask; |
332ac17e | 4719 | } |
f1e3a093 | 4720 | rcu_read_unlock(); |
332ac17e DF |
4721 | } |
4722 | #endif | |
49246274 | 4723 | again: |
25834c73 | 4724 | retval = __set_cpus_allowed_ptr(p, new_mask, true); |
1da177e4 | 4725 | |
8707d8b8 | 4726 | if (!retval) { |
5a16f3d3 RR |
4727 | cpuset_cpus_allowed(p, cpus_allowed); |
4728 | if (!cpumask_subset(new_mask, cpus_allowed)) { | |
8707d8b8 PM |
4729 | /* |
4730 | * We must have raced with a concurrent cpuset | |
4731 | * update. Just reset the cpus_allowed to the | |
4732 | * cpuset's cpus_allowed | |
4733 | */ | |
5a16f3d3 | 4734 | cpumask_copy(new_mask, cpus_allowed); |
8707d8b8 PM |
4735 | goto again; |
4736 | } | |
4737 | } | |
16303ab2 | 4738 | out_free_new_mask: |
5a16f3d3 RR |
4739 | free_cpumask_var(new_mask); |
4740 | out_free_cpus_allowed: | |
4741 | free_cpumask_var(cpus_allowed); | |
4742 | out_put_task: | |
1da177e4 | 4743 | put_task_struct(p); |
1da177e4 LT |
4744 | return retval; |
4745 | } | |
4746 | ||
4747 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
96f874e2 | 4748 | struct cpumask *new_mask) |
1da177e4 | 4749 | { |
96f874e2 RR |
4750 | if (len < cpumask_size()) |
4751 | cpumask_clear(new_mask); | |
4752 | else if (len > cpumask_size()) | |
4753 | len = cpumask_size(); | |
4754 | ||
1da177e4 LT |
4755 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
4756 | } | |
4757 | ||
4758 | /** | |
4759 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4760 | * @pid: pid of the process | |
4761 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4762 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
e69f6186 YB |
4763 | * |
4764 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4765 | */ |
5add95d4 HC |
4766 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
4767 | unsigned long __user *, user_mask_ptr) | |
1da177e4 | 4768 | { |
5a16f3d3 | 4769 | cpumask_var_t new_mask; |
1da177e4 LT |
4770 | int retval; |
4771 | ||
5a16f3d3 RR |
4772 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
4773 | return -ENOMEM; | |
1da177e4 | 4774 | |
5a16f3d3 RR |
4775 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
4776 | if (retval == 0) | |
4777 | retval = sched_setaffinity(pid, new_mask); | |
4778 | free_cpumask_var(new_mask); | |
4779 | return retval; | |
1da177e4 LT |
4780 | } |
4781 | ||
96f874e2 | 4782 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
1da177e4 | 4783 | { |
36c8b586 | 4784 | struct task_struct *p; |
31605683 | 4785 | unsigned long flags; |
1da177e4 | 4786 | int retval; |
1da177e4 | 4787 | |
23f5d142 | 4788 | rcu_read_lock(); |
1da177e4 LT |
4789 | |
4790 | retval = -ESRCH; | |
4791 | p = find_process_by_pid(pid); | |
4792 | if (!p) | |
4793 | goto out_unlock; | |
4794 | ||
e7834f8f DQ |
4795 | retval = security_task_getscheduler(p); |
4796 | if (retval) | |
4797 | goto out_unlock; | |
4798 | ||
013fdb80 | 4799 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
6acce3ef | 4800 | cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); |
013fdb80 | 4801 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
4802 | |
4803 | out_unlock: | |
23f5d142 | 4804 | rcu_read_unlock(); |
1da177e4 | 4805 | |
9531b62f | 4806 | return retval; |
1da177e4 LT |
4807 | } |
4808 | ||
4809 | /** | |
4810 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4811 | * @pid: pid of the process | |
4812 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4813 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
e69f6186 | 4814 | * |
599b4840 ZW |
4815 | * Return: size of CPU mask copied to user_mask_ptr on success. An |
4816 | * error code otherwise. | |
1da177e4 | 4817 | */ |
5add95d4 HC |
4818 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
4819 | unsigned long __user *, user_mask_ptr) | |
1da177e4 LT |
4820 | { |
4821 | int ret; | |
f17c8607 | 4822 | cpumask_var_t mask; |
1da177e4 | 4823 | |
84fba5ec | 4824 | if ((len * BITS_PER_BYTE) < nr_cpu_ids) |
cd3d8031 KM |
4825 | return -EINVAL; |
4826 | if (len & (sizeof(unsigned long)-1)) | |
1da177e4 LT |
4827 | return -EINVAL; |
4828 | ||
f17c8607 RR |
4829 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
4830 | return -ENOMEM; | |
1da177e4 | 4831 | |
f17c8607 RR |
4832 | ret = sched_getaffinity(pid, mask); |
4833 | if (ret == 0) { | |
8bc037fb | 4834 | size_t retlen = min_t(size_t, len, cpumask_size()); |
cd3d8031 KM |
4835 | |
4836 | if (copy_to_user(user_mask_ptr, mask, retlen)) | |
f17c8607 RR |
4837 | ret = -EFAULT; |
4838 | else | |
cd3d8031 | 4839 | ret = retlen; |
f17c8607 RR |
4840 | } |
4841 | free_cpumask_var(mask); | |
1da177e4 | 4842 | |
f17c8607 | 4843 | return ret; |
1da177e4 LT |
4844 | } |
4845 | ||
4846 | /** | |
4847 | * sys_sched_yield - yield the current processor to other threads. | |
4848 | * | |
dd41f596 IM |
4849 | * This function yields the current CPU to other tasks. If there are no |
4850 | * other threads running on this CPU then this function will return. | |
e69f6186 YB |
4851 | * |
4852 | * Return: 0. | |
1da177e4 | 4853 | */ |
5add95d4 | 4854 | SYSCALL_DEFINE0(sched_yield) |
1da177e4 | 4855 | { |
70b97a7f | 4856 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4857 | |
ae92882e | 4858 | schedstat_inc(rq->yld_count); |
4530d7ab | 4859 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4860 | |
4861 | /* | |
4862 | * Since we are going to call schedule() anyway, there's | |
4863 | * no need to preempt or enable interrupts: | |
4864 | */ | |
4865 | __release(rq->lock); | |
8a25d5de | 4866 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
9828ea9d | 4867 | do_raw_spin_unlock(&rq->lock); |
ba74c144 | 4868 | sched_preempt_enable_no_resched(); |
1da177e4 LT |
4869 | |
4870 | schedule(); | |
4871 | ||
4872 | return 0; | |
4873 | } | |
4874 | ||
02b67cc3 | 4875 | int __sched _cond_resched(void) |
1da177e4 | 4876 | { |
fe32d3cd | 4877 | if (should_resched(0)) { |
a18b5d01 | 4878 | preempt_schedule_common(); |
1da177e4 LT |
4879 | return 1; |
4880 | } | |
4881 | return 0; | |
4882 | } | |
02b67cc3 | 4883 | EXPORT_SYMBOL(_cond_resched); |
1da177e4 LT |
4884 | |
4885 | /* | |
613afbf8 | 4886 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
1da177e4 LT |
4887 | * call schedule, and on return reacquire the lock. |
4888 | * | |
41a2d6cf | 4889 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
4890 | * operations here to prevent schedule() from being called twice (once via |
4891 | * spin_unlock(), once by hand). | |
4892 | */ | |
613afbf8 | 4893 | int __cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4894 | { |
fe32d3cd | 4895 | int resched = should_resched(PREEMPT_LOCK_OFFSET); |
6df3cecb JK |
4896 | int ret = 0; |
4897 | ||
f607c668 PZ |
4898 | lockdep_assert_held(lock); |
4899 | ||
4a81e832 | 4900 | if (spin_needbreak(lock) || resched) { |
1da177e4 | 4901 | spin_unlock(lock); |
d86ee480 | 4902 | if (resched) |
a18b5d01 | 4903 | preempt_schedule_common(); |
95c354fe NP |
4904 | else |
4905 | cpu_relax(); | |
6df3cecb | 4906 | ret = 1; |
1da177e4 | 4907 | spin_lock(lock); |
1da177e4 | 4908 | } |
6df3cecb | 4909 | return ret; |
1da177e4 | 4910 | } |
613afbf8 | 4911 | EXPORT_SYMBOL(__cond_resched_lock); |
1da177e4 | 4912 | |
613afbf8 | 4913 | int __sched __cond_resched_softirq(void) |
1da177e4 LT |
4914 | { |
4915 | BUG_ON(!in_softirq()); | |
4916 | ||
fe32d3cd | 4917 | if (should_resched(SOFTIRQ_DISABLE_OFFSET)) { |
98d82567 | 4918 | local_bh_enable(); |
a18b5d01 | 4919 | preempt_schedule_common(); |
1da177e4 LT |
4920 | local_bh_disable(); |
4921 | return 1; | |
4922 | } | |
4923 | return 0; | |
4924 | } | |
613afbf8 | 4925 | EXPORT_SYMBOL(__cond_resched_softirq); |
1da177e4 | 4926 | |
1da177e4 LT |
4927 | /** |
4928 | * yield - yield the current processor to other threads. | |
4929 | * | |
8e3fabfd PZ |
4930 | * Do not ever use this function, there's a 99% chance you're doing it wrong. |
4931 | * | |
4932 | * The scheduler is at all times free to pick the calling task as the most | |
4933 | * eligible task to run, if removing the yield() call from your code breaks | |
4934 | * it, its already broken. | |
4935 | * | |
4936 | * Typical broken usage is: | |
4937 | * | |
4938 | * while (!event) | |
4939 | * yield(); | |
4940 | * | |
4941 | * where one assumes that yield() will let 'the other' process run that will | |
4942 | * make event true. If the current task is a SCHED_FIFO task that will never | |
4943 | * happen. Never use yield() as a progress guarantee!! | |
4944 | * | |
4945 | * If you want to use yield() to wait for something, use wait_event(). | |
4946 | * If you want to use yield() to be 'nice' for others, use cond_resched(). | |
4947 | * If you still want to use yield(), do not! | |
1da177e4 LT |
4948 | */ |
4949 | void __sched yield(void) | |
4950 | { | |
4951 | set_current_state(TASK_RUNNING); | |
4952 | sys_sched_yield(); | |
4953 | } | |
1da177e4 LT |
4954 | EXPORT_SYMBOL(yield); |
4955 | ||
d95f4122 MG |
4956 | /** |
4957 | * yield_to - yield the current processor to another thread in | |
4958 | * your thread group, or accelerate that thread toward the | |
4959 | * processor it's on. | |
16addf95 RD |
4960 | * @p: target task |
4961 | * @preempt: whether task preemption is allowed or not | |
d95f4122 MG |
4962 | * |
4963 | * It's the caller's job to ensure that the target task struct | |
4964 | * can't go away on us before we can do any checks. | |
4965 | * | |
e69f6186 | 4966 | * Return: |
7b270f60 PZ |
4967 | * true (>0) if we indeed boosted the target task. |
4968 | * false (0) if we failed to boost the target. | |
4969 | * -ESRCH if there's no task to yield to. | |
d95f4122 | 4970 | */ |
fa93384f | 4971 | int __sched yield_to(struct task_struct *p, bool preempt) |
d95f4122 MG |
4972 | { |
4973 | struct task_struct *curr = current; | |
4974 | struct rq *rq, *p_rq; | |
4975 | unsigned long flags; | |
c3c18640 | 4976 | int yielded = 0; |
d95f4122 MG |
4977 | |
4978 | local_irq_save(flags); | |
4979 | rq = this_rq(); | |
4980 | ||
4981 | again: | |
4982 | p_rq = task_rq(p); | |
7b270f60 PZ |
4983 | /* |
4984 | * If we're the only runnable task on the rq and target rq also | |
4985 | * has only one task, there's absolutely no point in yielding. | |
4986 | */ | |
4987 | if (rq->nr_running == 1 && p_rq->nr_running == 1) { | |
4988 | yielded = -ESRCH; | |
4989 | goto out_irq; | |
4990 | } | |
4991 | ||
d95f4122 | 4992 | double_rq_lock(rq, p_rq); |
39e24d8f | 4993 | if (task_rq(p) != p_rq) { |
d95f4122 MG |
4994 | double_rq_unlock(rq, p_rq); |
4995 | goto again; | |
4996 | } | |
4997 | ||
4998 | if (!curr->sched_class->yield_to_task) | |
7b270f60 | 4999 | goto out_unlock; |
d95f4122 MG |
5000 | |
5001 | if (curr->sched_class != p->sched_class) | |
7b270f60 | 5002 | goto out_unlock; |
d95f4122 MG |
5003 | |
5004 | if (task_running(p_rq, p) || p->state) | |
7b270f60 | 5005 | goto out_unlock; |
d95f4122 MG |
5006 | |
5007 | yielded = curr->sched_class->yield_to_task(rq, p, preempt); | |
6d1cafd8 | 5008 | if (yielded) { |
ae92882e | 5009 | schedstat_inc(rq->yld_count); |
6d1cafd8 VP |
5010 | /* |
5011 | * Make p's CPU reschedule; pick_next_entity takes care of | |
5012 | * fairness. | |
5013 | */ | |
5014 | if (preempt && rq != p_rq) | |
8875125e | 5015 | resched_curr(p_rq); |
6d1cafd8 | 5016 | } |
d95f4122 | 5017 | |
7b270f60 | 5018 | out_unlock: |
d95f4122 | 5019 | double_rq_unlock(rq, p_rq); |
7b270f60 | 5020 | out_irq: |
d95f4122 MG |
5021 | local_irq_restore(flags); |
5022 | ||
7b270f60 | 5023 | if (yielded > 0) |
d95f4122 MG |
5024 | schedule(); |
5025 | ||
5026 | return yielded; | |
5027 | } | |
5028 | EXPORT_SYMBOL_GPL(yield_to); | |
5029 | ||
1da177e4 | 5030 | /* |
41a2d6cf | 5031 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 | 5032 | * that process accounting knows that this is a task in IO wait state. |
1da177e4 | 5033 | */ |
1da177e4 LT |
5034 | long __sched io_schedule_timeout(long timeout) |
5035 | { | |
9cff8ade N |
5036 | int old_iowait = current->in_iowait; |
5037 | struct rq *rq; | |
1da177e4 LT |
5038 | long ret; |
5039 | ||
9cff8ade | 5040 | current->in_iowait = 1; |
10d784ea | 5041 | blk_schedule_flush_plug(current); |
9cff8ade | 5042 | |
0ff92245 | 5043 | delayacct_blkio_start(); |
9cff8ade | 5044 | rq = raw_rq(); |
1da177e4 LT |
5045 | atomic_inc(&rq->nr_iowait); |
5046 | ret = schedule_timeout(timeout); | |
9cff8ade | 5047 | current->in_iowait = old_iowait; |
1da177e4 | 5048 | atomic_dec(&rq->nr_iowait); |
0ff92245 | 5049 | delayacct_blkio_end(); |
9cff8ade | 5050 | |
1da177e4 LT |
5051 | return ret; |
5052 | } | |
9cff8ade | 5053 | EXPORT_SYMBOL(io_schedule_timeout); |
1da177e4 LT |
5054 | |
5055 | /** | |
5056 | * sys_sched_get_priority_max - return maximum RT priority. | |
5057 | * @policy: scheduling class. | |
5058 | * | |
e69f6186 YB |
5059 | * Return: On success, this syscall returns the maximum |
5060 | * rt_priority that can be used by a given scheduling class. | |
5061 | * On failure, a negative error code is returned. | |
1da177e4 | 5062 | */ |
5add95d4 | 5063 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
1da177e4 LT |
5064 | { |
5065 | int ret = -EINVAL; | |
5066 | ||
5067 | switch (policy) { | |
5068 | case SCHED_FIFO: | |
5069 | case SCHED_RR: | |
5070 | ret = MAX_USER_RT_PRIO-1; | |
5071 | break; | |
aab03e05 | 5072 | case SCHED_DEADLINE: |
1da177e4 | 5073 | case SCHED_NORMAL: |
b0a9499c | 5074 | case SCHED_BATCH: |
dd41f596 | 5075 | case SCHED_IDLE: |
1da177e4 LT |
5076 | ret = 0; |
5077 | break; | |
5078 | } | |
5079 | return ret; | |
5080 | } | |
5081 | ||
5082 | /** | |
5083 | * sys_sched_get_priority_min - return minimum RT priority. | |
5084 | * @policy: scheduling class. | |
5085 | * | |
e69f6186 YB |
5086 | * Return: On success, this syscall returns the minimum |
5087 | * rt_priority that can be used by a given scheduling class. | |
5088 | * On failure, a negative error code is returned. | |
1da177e4 | 5089 | */ |
5add95d4 | 5090 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
1da177e4 LT |
5091 | { |
5092 | int ret = -EINVAL; | |
5093 | ||
5094 | switch (policy) { | |
5095 | case SCHED_FIFO: | |
5096 | case SCHED_RR: | |
5097 | ret = 1; | |
5098 | break; | |
aab03e05 | 5099 | case SCHED_DEADLINE: |
1da177e4 | 5100 | case SCHED_NORMAL: |
b0a9499c | 5101 | case SCHED_BATCH: |
dd41f596 | 5102 | case SCHED_IDLE: |
1da177e4 LT |
5103 | ret = 0; |
5104 | } | |
5105 | return ret; | |
5106 | } | |
5107 | ||
5108 | /** | |
5109 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
5110 | * @pid: pid of the process. | |
5111 | * @interval: userspace pointer to the timeslice value. | |
5112 | * | |
5113 | * this syscall writes the default timeslice value of a given process | |
5114 | * into the user-space timespec buffer. A value of '0' means infinity. | |
e69f6186 YB |
5115 | * |
5116 | * Return: On success, 0 and the timeslice is in @interval. Otherwise, | |
5117 | * an error code. | |
1da177e4 | 5118 | */ |
17da2bd9 | 5119 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
754fe8d2 | 5120 | struct timespec __user *, interval) |
1da177e4 | 5121 | { |
36c8b586 | 5122 | struct task_struct *p; |
a4ec24b4 | 5123 | unsigned int time_slice; |
eb580751 PZ |
5124 | struct rq_flags rf; |
5125 | struct timespec t; | |
dba091b9 | 5126 | struct rq *rq; |
3a5c359a | 5127 | int retval; |
1da177e4 LT |
5128 | |
5129 | if (pid < 0) | |
3a5c359a | 5130 | return -EINVAL; |
1da177e4 LT |
5131 | |
5132 | retval = -ESRCH; | |
1a551ae7 | 5133 | rcu_read_lock(); |
1da177e4 LT |
5134 | p = find_process_by_pid(pid); |
5135 | if (!p) | |
5136 | goto out_unlock; | |
5137 | ||
5138 | retval = security_task_getscheduler(p); | |
5139 | if (retval) | |
5140 | goto out_unlock; | |
5141 | ||
eb580751 | 5142 | rq = task_rq_lock(p, &rf); |
a57beec5 PZ |
5143 | time_slice = 0; |
5144 | if (p->sched_class->get_rr_interval) | |
5145 | time_slice = p->sched_class->get_rr_interval(rq, p); | |
eb580751 | 5146 | task_rq_unlock(rq, p, &rf); |
a4ec24b4 | 5147 | |
1a551ae7 | 5148 | rcu_read_unlock(); |
a4ec24b4 | 5149 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 5150 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 5151 | return retval; |
3a5c359a | 5152 | |
1da177e4 | 5153 | out_unlock: |
1a551ae7 | 5154 | rcu_read_unlock(); |
1da177e4 LT |
5155 | return retval; |
5156 | } | |
5157 | ||
7c731e0a | 5158 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
36c8b586 | 5159 | |
82a1fcb9 | 5160 | void sched_show_task(struct task_struct *p) |
1da177e4 | 5161 | { |
1da177e4 | 5162 | unsigned long free = 0; |
4e79752c | 5163 | int ppid; |
1f8a7633 | 5164 | unsigned long state = p->state; |
1da177e4 | 5165 | |
1f8a7633 TH |
5166 | if (state) |
5167 | state = __ffs(state) + 1; | |
28d0686c | 5168 | printk(KERN_INFO "%-15.15s %c", p->comm, |
2ed6e34f | 5169 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 5170 | #if BITS_PER_LONG == 32 |
1da177e4 | 5171 | if (state == TASK_RUNNING) |
3df0fc5b | 5172 | printk(KERN_CONT " running "); |
1da177e4 | 5173 | else |
3df0fc5b | 5174 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
5175 | #else |
5176 | if (state == TASK_RUNNING) | |
3df0fc5b | 5177 | printk(KERN_CONT " running task "); |
1da177e4 | 5178 | else |
3df0fc5b | 5179 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
5180 | #endif |
5181 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
7c9f8861 | 5182 | free = stack_not_used(p); |
1da177e4 | 5183 | #endif |
a90e984c | 5184 | ppid = 0; |
4e79752c | 5185 | rcu_read_lock(); |
a90e984c ON |
5186 | if (pid_alive(p)) |
5187 | ppid = task_pid_nr(rcu_dereference(p->real_parent)); | |
4e79752c | 5188 | rcu_read_unlock(); |
3df0fc5b | 5189 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
4e79752c | 5190 | task_pid_nr(p), ppid, |
aa47b7e0 | 5191 | (unsigned long)task_thread_info(p)->flags); |
1da177e4 | 5192 | |
3d1cb205 | 5193 | print_worker_info(KERN_INFO, p); |
5fb5e6de | 5194 | show_stack(p, NULL); |
1da177e4 LT |
5195 | } |
5196 | ||
e59e2ae2 | 5197 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 5198 | { |
36c8b586 | 5199 | struct task_struct *g, *p; |
1da177e4 | 5200 | |
4bd77321 | 5201 | #if BITS_PER_LONG == 32 |
3df0fc5b PZ |
5202 | printk(KERN_INFO |
5203 | " task PC stack pid father\n"); | |
1da177e4 | 5204 | #else |
3df0fc5b PZ |
5205 | printk(KERN_INFO |
5206 | " task PC stack pid father\n"); | |
1da177e4 | 5207 | #endif |
510f5acc | 5208 | rcu_read_lock(); |
5d07f420 | 5209 | for_each_process_thread(g, p) { |
1da177e4 LT |
5210 | /* |
5211 | * reset the NMI-timeout, listing all files on a slow | |
25985edc | 5212 | * console might take a lot of time: |
57675cb9 AR |
5213 | * Also, reset softlockup watchdogs on all CPUs, because |
5214 | * another CPU might be blocked waiting for us to process | |
5215 | * an IPI. | |
1da177e4 LT |
5216 | */ |
5217 | touch_nmi_watchdog(); | |
57675cb9 | 5218 | touch_all_softlockup_watchdogs(); |
39bc89fd | 5219 | if (!state_filter || (p->state & state_filter)) |
82a1fcb9 | 5220 | sched_show_task(p); |
5d07f420 | 5221 | } |
1da177e4 | 5222 | |
dd41f596 | 5223 | #ifdef CONFIG_SCHED_DEBUG |
fb90a6e9 RV |
5224 | if (!state_filter) |
5225 | sysrq_sched_debug_show(); | |
dd41f596 | 5226 | #endif |
510f5acc | 5227 | rcu_read_unlock(); |
e59e2ae2 IM |
5228 | /* |
5229 | * Only show locks if all tasks are dumped: | |
5230 | */ | |
93335a21 | 5231 | if (!state_filter) |
e59e2ae2 | 5232 | debug_show_all_locks(); |
1da177e4 LT |
5233 | } |
5234 | ||
0db0628d | 5235 | void init_idle_bootup_task(struct task_struct *idle) |
1df21055 | 5236 | { |
dd41f596 | 5237 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
5238 | } |
5239 | ||
f340c0d1 IM |
5240 | /** |
5241 | * init_idle - set up an idle thread for a given CPU | |
5242 | * @idle: task in question | |
5243 | * @cpu: cpu the idle task belongs to | |
5244 | * | |
5245 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
5246 | * flag, to make booting more robust. | |
5247 | */ | |
0db0628d | 5248 | void init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 5249 | { |
70b97a7f | 5250 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
5251 | unsigned long flags; |
5252 | ||
25834c73 PZ |
5253 | raw_spin_lock_irqsave(&idle->pi_lock, flags); |
5254 | raw_spin_lock(&rq->lock); | |
5cbd54ef | 5255 | |
5e1576ed | 5256 | __sched_fork(0, idle); |
06b83b5f | 5257 | idle->state = TASK_RUNNING; |
dd41f596 IM |
5258 | idle->se.exec_start = sched_clock(); |
5259 | ||
e1b77c92 MR |
5260 | kasan_unpoison_task_stack(idle); |
5261 | ||
de9b8f5d PZ |
5262 | #ifdef CONFIG_SMP |
5263 | /* | |
5264 | * Its possible that init_idle() gets called multiple times on a task, | |
5265 | * in that case do_set_cpus_allowed() will not do the right thing. | |
5266 | * | |
5267 | * And since this is boot we can forgo the serialization. | |
5268 | */ | |
5269 | set_cpus_allowed_common(idle, cpumask_of(cpu)); | |
5270 | #endif | |
6506cf6c PZ |
5271 | /* |
5272 | * We're having a chicken and egg problem, even though we are | |
5273 | * holding rq->lock, the cpu isn't yet set to this cpu so the | |
5274 | * lockdep check in task_group() will fail. | |
5275 | * | |
5276 | * Similar case to sched_fork(). / Alternatively we could | |
5277 | * use task_rq_lock() here and obtain the other rq->lock. | |
5278 | * | |
5279 | * Silence PROVE_RCU | |
5280 | */ | |
5281 | rcu_read_lock(); | |
dd41f596 | 5282 | __set_task_cpu(idle, cpu); |
6506cf6c | 5283 | rcu_read_unlock(); |
1da177e4 | 5284 | |
1da177e4 | 5285 | rq->curr = rq->idle = idle; |
da0c1e65 | 5286 | idle->on_rq = TASK_ON_RQ_QUEUED; |
de9b8f5d | 5287 | #ifdef CONFIG_SMP |
3ca7a440 | 5288 | idle->on_cpu = 1; |
4866cde0 | 5289 | #endif |
25834c73 PZ |
5290 | raw_spin_unlock(&rq->lock); |
5291 | raw_spin_unlock_irqrestore(&idle->pi_lock, flags); | |
1da177e4 LT |
5292 | |
5293 | /* Set the preempt count _outside_ the spinlocks! */ | |
01028747 | 5294 | init_idle_preempt_count(idle, cpu); |
55cd5340 | 5295 | |
dd41f596 IM |
5296 | /* |
5297 | * The idle tasks have their own, simple scheduling class: | |
5298 | */ | |
5299 | idle->sched_class = &idle_sched_class; | |
868baf07 | 5300 | ftrace_graph_init_idle_task(idle, cpu); |
45eacc69 | 5301 | vtime_init_idle(idle, cpu); |
de9b8f5d | 5302 | #ifdef CONFIG_SMP |
f1c6f1a7 CE |
5303 | sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); |
5304 | #endif | |
19978ca6 IM |
5305 | } |
5306 | ||
f82f8042 JL |
5307 | int cpuset_cpumask_can_shrink(const struct cpumask *cur, |
5308 | const struct cpumask *trial) | |
5309 | { | |
5310 | int ret = 1, trial_cpus; | |
5311 | struct dl_bw *cur_dl_b; | |
5312 | unsigned long flags; | |
5313 | ||
bb2bc55a MG |
5314 | if (!cpumask_weight(cur)) |
5315 | return ret; | |
5316 | ||
75e23e49 | 5317 | rcu_read_lock_sched(); |
f82f8042 JL |
5318 | cur_dl_b = dl_bw_of(cpumask_any(cur)); |
5319 | trial_cpus = cpumask_weight(trial); | |
5320 | ||
5321 | raw_spin_lock_irqsave(&cur_dl_b->lock, flags); | |
5322 | if (cur_dl_b->bw != -1 && | |
5323 | cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw) | |
5324 | ret = 0; | |
5325 | raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); | |
75e23e49 | 5326 | rcu_read_unlock_sched(); |
f82f8042 JL |
5327 | |
5328 | return ret; | |
5329 | } | |
5330 | ||
7f51412a JL |
5331 | int task_can_attach(struct task_struct *p, |
5332 | const struct cpumask *cs_cpus_allowed) | |
5333 | { | |
5334 | int ret = 0; | |
5335 | ||
5336 | /* | |
5337 | * Kthreads which disallow setaffinity shouldn't be moved | |
5338 | * to a new cpuset; we don't want to change their cpu | |
5339 | * affinity and isolating such threads by their set of | |
5340 | * allowed nodes is unnecessary. Thus, cpusets are not | |
5341 | * applicable for such threads. This prevents checking for | |
5342 | * success of set_cpus_allowed_ptr() on all attached tasks | |
5343 | * before cpus_allowed may be changed. | |
5344 | */ | |
5345 | if (p->flags & PF_NO_SETAFFINITY) { | |
5346 | ret = -EINVAL; | |
5347 | goto out; | |
5348 | } | |
5349 | ||
5350 | #ifdef CONFIG_SMP | |
5351 | if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span, | |
5352 | cs_cpus_allowed)) { | |
5353 | unsigned int dest_cpu = cpumask_any_and(cpu_active_mask, | |
5354 | cs_cpus_allowed); | |
75e23e49 | 5355 | struct dl_bw *dl_b; |
7f51412a JL |
5356 | bool overflow; |
5357 | int cpus; | |
5358 | unsigned long flags; | |
5359 | ||
75e23e49 JL |
5360 | rcu_read_lock_sched(); |
5361 | dl_b = dl_bw_of(dest_cpu); | |
7f51412a JL |
5362 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
5363 | cpus = dl_bw_cpus(dest_cpu); | |
5364 | overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw); | |
5365 | if (overflow) | |
5366 | ret = -EBUSY; | |
5367 | else { | |
5368 | /* | |
5369 | * We reserve space for this task in the destination | |
5370 | * root_domain, as we can't fail after this point. | |
5371 | * We will free resources in the source root_domain | |
5372 | * later on (see set_cpus_allowed_dl()). | |
5373 | */ | |
5374 | __dl_add(dl_b, p->dl.dl_bw); | |
5375 | } | |
5376 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
75e23e49 | 5377 | rcu_read_unlock_sched(); |
7f51412a JL |
5378 | |
5379 | } | |
5380 | #endif | |
5381 | out: | |
5382 | return ret; | |
5383 | } | |
5384 | ||
1da177e4 | 5385 | #ifdef CONFIG_SMP |
1da177e4 | 5386 | |
e26fbffd TG |
5387 | static bool sched_smp_initialized __read_mostly; |
5388 | ||
e6628d5b MG |
5389 | #ifdef CONFIG_NUMA_BALANCING |
5390 | /* Migrate current task p to target_cpu */ | |
5391 | int migrate_task_to(struct task_struct *p, int target_cpu) | |
5392 | { | |
5393 | struct migration_arg arg = { p, target_cpu }; | |
5394 | int curr_cpu = task_cpu(p); | |
5395 | ||
5396 | if (curr_cpu == target_cpu) | |
5397 | return 0; | |
5398 | ||
5399 | if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) | |
5400 | return -EINVAL; | |
5401 | ||
5402 | /* TODO: This is not properly updating schedstats */ | |
5403 | ||
286549dc | 5404 | trace_sched_move_numa(p, curr_cpu, target_cpu); |
e6628d5b MG |
5405 | return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); |
5406 | } | |
0ec8aa00 PZ |
5407 | |
5408 | /* | |
5409 | * Requeue a task on a given node and accurately track the number of NUMA | |
5410 | * tasks on the runqueues | |
5411 | */ | |
5412 | void sched_setnuma(struct task_struct *p, int nid) | |
5413 | { | |
da0c1e65 | 5414 | bool queued, running; |
eb580751 PZ |
5415 | struct rq_flags rf; |
5416 | struct rq *rq; | |
0ec8aa00 | 5417 | |
eb580751 | 5418 | rq = task_rq_lock(p, &rf); |
da0c1e65 | 5419 | queued = task_on_rq_queued(p); |
0ec8aa00 PZ |
5420 | running = task_current(rq, p); |
5421 | ||
da0c1e65 | 5422 | if (queued) |
1de64443 | 5423 | dequeue_task(rq, p, DEQUEUE_SAVE); |
0ec8aa00 | 5424 | if (running) |
f3cd1c4e | 5425 | put_prev_task(rq, p); |
0ec8aa00 PZ |
5426 | |
5427 | p->numa_preferred_nid = nid; | |
0ec8aa00 PZ |
5428 | |
5429 | if (running) | |
5430 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 5431 | if (queued) |
1de64443 | 5432 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
eb580751 | 5433 | task_rq_unlock(rq, p, &rf); |
0ec8aa00 | 5434 | } |
5cc389bc | 5435 | #endif /* CONFIG_NUMA_BALANCING */ |
f7b4cddc | 5436 | |
1da177e4 | 5437 | #ifdef CONFIG_HOTPLUG_CPU |
054b9108 | 5438 | /* |
48c5ccae PZ |
5439 | * Ensures that the idle task is using init_mm right before its cpu goes |
5440 | * offline. | |
054b9108 | 5441 | */ |
48c5ccae | 5442 | void idle_task_exit(void) |
1da177e4 | 5443 | { |
48c5ccae | 5444 | struct mm_struct *mm = current->active_mm; |
e76bd8d9 | 5445 | |
48c5ccae | 5446 | BUG_ON(cpu_online(smp_processor_id())); |
e76bd8d9 | 5447 | |
a53efe5f | 5448 | if (mm != &init_mm) { |
f98db601 | 5449 | switch_mm_irqs_off(mm, &init_mm, current); |
a53efe5f MS |
5450 | finish_arch_post_lock_switch(); |
5451 | } | |
48c5ccae | 5452 | mmdrop(mm); |
1da177e4 LT |
5453 | } |
5454 | ||
5455 | /* | |
5d180232 PZ |
5456 | * Since this CPU is going 'away' for a while, fold any nr_active delta |
5457 | * we might have. Assumes we're called after migrate_tasks() so that the | |
d60585c5 TG |
5458 | * nr_active count is stable. We need to take the teardown thread which |
5459 | * is calling this into account, so we hand in adjust = 1 to the load | |
5460 | * calculation. | |
5d180232 PZ |
5461 | * |
5462 | * Also see the comment "Global load-average calculations". | |
1da177e4 | 5463 | */ |
5d180232 | 5464 | static void calc_load_migrate(struct rq *rq) |
1da177e4 | 5465 | { |
d60585c5 | 5466 | long delta = calc_load_fold_active(rq, 1); |
5d180232 PZ |
5467 | if (delta) |
5468 | atomic_long_add(delta, &calc_load_tasks); | |
1da177e4 LT |
5469 | } |
5470 | ||
3f1d2a31 PZ |
5471 | static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) |
5472 | { | |
5473 | } | |
5474 | ||
5475 | static const struct sched_class fake_sched_class = { | |
5476 | .put_prev_task = put_prev_task_fake, | |
5477 | }; | |
5478 | ||
5479 | static struct task_struct fake_task = { | |
5480 | /* | |
5481 | * Avoid pull_{rt,dl}_task() | |
5482 | */ | |
5483 | .prio = MAX_PRIO + 1, | |
5484 | .sched_class = &fake_sched_class, | |
5485 | }; | |
5486 | ||
48f24c4d | 5487 | /* |
48c5ccae PZ |
5488 | * Migrate all tasks from the rq, sleeping tasks will be migrated by |
5489 | * try_to_wake_up()->select_task_rq(). | |
5490 | * | |
5491 | * Called with rq->lock held even though we'er in stop_machine() and | |
5492 | * there's no concurrency possible, we hold the required locks anyway | |
5493 | * because of lock validation efforts. | |
1da177e4 | 5494 | */ |
5e16bbc2 | 5495 | static void migrate_tasks(struct rq *dead_rq) |
1da177e4 | 5496 | { |
5e16bbc2 | 5497 | struct rq *rq = dead_rq; |
48c5ccae | 5498 | struct task_struct *next, *stop = rq->stop; |
e7904a28 | 5499 | struct pin_cookie cookie; |
48c5ccae | 5500 | int dest_cpu; |
1da177e4 LT |
5501 | |
5502 | /* | |
48c5ccae PZ |
5503 | * Fudge the rq selection such that the below task selection loop |
5504 | * doesn't get stuck on the currently eligible stop task. | |
5505 | * | |
5506 | * We're currently inside stop_machine() and the rq is either stuck | |
5507 | * in the stop_machine_cpu_stop() loop, or we're executing this code, | |
5508 | * either way we should never end up calling schedule() until we're | |
5509 | * done here. | |
1da177e4 | 5510 | */ |
48c5ccae | 5511 | rq->stop = NULL; |
48f24c4d | 5512 | |
77bd3970 FW |
5513 | /* |
5514 | * put_prev_task() and pick_next_task() sched | |
5515 | * class method both need to have an up-to-date | |
5516 | * value of rq->clock[_task] | |
5517 | */ | |
5518 | update_rq_clock(rq); | |
5519 | ||
5e16bbc2 | 5520 | for (;;) { |
48c5ccae PZ |
5521 | /* |
5522 | * There's this thread running, bail when that's the only | |
5523 | * remaining thread. | |
5524 | */ | |
5525 | if (rq->nr_running == 1) | |
dd41f596 | 5526 | break; |
48c5ccae | 5527 | |
cbce1a68 | 5528 | /* |
5473e0cc | 5529 | * pick_next_task assumes pinned rq->lock. |
cbce1a68 | 5530 | */ |
e7904a28 PZ |
5531 | cookie = lockdep_pin_lock(&rq->lock); |
5532 | next = pick_next_task(rq, &fake_task, cookie); | |
48c5ccae | 5533 | BUG_ON(!next); |
79c53799 | 5534 | next->sched_class->put_prev_task(rq, next); |
e692ab53 | 5535 | |
5473e0cc WL |
5536 | /* |
5537 | * Rules for changing task_struct::cpus_allowed are holding | |
5538 | * both pi_lock and rq->lock, such that holding either | |
5539 | * stabilizes the mask. | |
5540 | * | |
5541 | * Drop rq->lock is not quite as disastrous as it usually is | |
5542 | * because !cpu_active at this point, which means load-balance | |
5543 | * will not interfere. Also, stop-machine. | |
5544 | */ | |
e7904a28 | 5545 | lockdep_unpin_lock(&rq->lock, cookie); |
5473e0cc WL |
5546 | raw_spin_unlock(&rq->lock); |
5547 | raw_spin_lock(&next->pi_lock); | |
5548 | raw_spin_lock(&rq->lock); | |
5549 | ||
5550 | /* | |
5551 | * Since we're inside stop-machine, _nothing_ should have | |
5552 | * changed the task, WARN if weird stuff happened, because in | |
5553 | * that case the above rq->lock drop is a fail too. | |
5554 | */ | |
5555 | if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) { | |
5556 | raw_spin_unlock(&next->pi_lock); | |
5557 | continue; | |
5558 | } | |
5559 | ||
48c5ccae | 5560 | /* Find suitable destination for @next, with force if needed. */ |
5e16bbc2 | 5561 | dest_cpu = select_fallback_rq(dead_rq->cpu, next); |
48c5ccae | 5562 | |
5e16bbc2 PZ |
5563 | rq = __migrate_task(rq, next, dest_cpu); |
5564 | if (rq != dead_rq) { | |
5565 | raw_spin_unlock(&rq->lock); | |
5566 | rq = dead_rq; | |
5567 | raw_spin_lock(&rq->lock); | |
5568 | } | |
5473e0cc | 5569 | raw_spin_unlock(&next->pi_lock); |
1da177e4 | 5570 | } |
dce48a84 | 5571 | |
48c5ccae | 5572 | rq->stop = stop; |
dce48a84 | 5573 | } |
1da177e4 LT |
5574 | #endif /* CONFIG_HOTPLUG_CPU */ |
5575 | ||
1f11eb6a GH |
5576 | static void set_rq_online(struct rq *rq) |
5577 | { | |
5578 | if (!rq->online) { | |
5579 | const struct sched_class *class; | |
5580 | ||
c6c4927b | 5581 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
5582 | rq->online = 1; |
5583 | ||
5584 | for_each_class(class) { | |
5585 | if (class->rq_online) | |
5586 | class->rq_online(rq); | |
5587 | } | |
5588 | } | |
5589 | } | |
5590 | ||
5591 | static void set_rq_offline(struct rq *rq) | |
5592 | { | |
5593 | if (rq->online) { | |
5594 | const struct sched_class *class; | |
5595 | ||
5596 | for_each_class(class) { | |
5597 | if (class->rq_offline) | |
5598 | class->rq_offline(rq); | |
5599 | } | |
5600 | ||
c6c4927b | 5601 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
5602 | rq->online = 0; |
5603 | } | |
5604 | } | |
5605 | ||
9cf7243d | 5606 | static void set_cpu_rq_start_time(unsigned int cpu) |
1da177e4 | 5607 | { |
969c7921 | 5608 | struct rq *rq = cpu_rq(cpu); |
1da177e4 | 5609 | |
a803f026 CM |
5610 | rq->age_stamp = sched_clock_cpu(cpu); |
5611 | } | |
5612 | ||
4cb98839 PZ |
5613 | static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ |
5614 | ||
3e9830dc | 5615 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff | 5616 | |
d039ac60 | 5617 | static __read_mostly int sched_debug_enabled; |
f6630114 | 5618 | |
d039ac60 | 5619 | static int __init sched_debug_setup(char *str) |
f6630114 | 5620 | { |
d039ac60 | 5621 | sched_debug_enabled = 1; |
f6630114 MT |
5622 | |
5623 | return 0; | |
5624 | } | |
d039ac60 PZ |
5625 | early_param("sched_debug", sched_debug_setup); |
5626 | ||
5627 | static inline bool sched_debug(void) | |
5628 | { | |
5629 | return sched_debug_enabled; | |
5630 | } | |
f6630114 | 5631 | |
7c16ec58 | 5632 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
96f874e2 | 5633 | struct cpumask *groupmask) |
1da177e4 | 5634 | { |
4dcf6aff | 5635 | struct sched_group *group = sd->groups; |
1da177e4 | 5636 | |
96f874e2 | 5637 | cpumask_clear(groupmask); |
4dcf6aff IM |
5638 | |
5639 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
5640 | ||
5641 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
3df0fc5b | 5642 | printk("does not load-balance\n"); |
4dcf6aff | 5643 | if (sd->parent) |
3df0fc5b PZ |
5644 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5645 | " has parent"); | |
4dcf6aff | 5646 | return -1; |
41c7ce9a NP |
5647 | } |
5648 | ||
333470ee TH |
5649 | printk(KERN_CONT "span %*pbl level %s\n", |
5650 | cpumask_pr_args(sched_domain_span(sd)), sd->name); | |
4dcf6aff | 5651 | |
758b2cdc | 5652 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
3df0fc5b PZ |
5653 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5654 | "CPU%d\n", cpu); | |
4dcf6aff | 5655 | } |
758b2cdc | 5656 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
3df0fc5b PZ |
5657 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5658 | " CPU%d\n", cpu); | |
4dcf6aff | 5659 | } |
1da177e4 | 5660 | |
4dcf6aff | 5661 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 5662 | do { |
4dcf6aff | 5663 | if (!group) { |
3df0fc5b PZ |
5664 | printk("\n"); |
5665 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
5666 | break; |
5667 | } | |
5668 | ||
758b2cdc | 5669 | if (!cpumask_weight(sched_group_cpus(group))) { |
3df0fc5b PZ |
5670 | printk(KERN_CONT "\n"); |
5671 | printk(KERN_ERR "ERROR: empty group\n"); | |
4dcf6aff IM |
5672 | break; |
5673 | } | |
1da177e4 | 5674 | |
cb83b629 PZ |
5675 | if (!(sd->flags & SD_OVERLAP) && |
5676 | cpumask_intersects(groupmask, sched_group_cpus(group))) { | |
3df0fc5b PZ |
5677 | printk(KERN_CONT "\n"); |
5678 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
4dcf6aff IM |
5679 | break; |
5680 | } | |
1da177e4 | 5681 | |
758b2cdc | 5682 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
1da177e4 | 5683 | |
333470ee TH |
5684 | printk(KERN_CONT " %*pbl", |
5685 | cpumask_pr_args(sched_group_cpus(group))); | |
ca8ce3d0 | 5686 | if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { |
63b2ca30 NP |
5687 | printk(KERN_CONT " (cpu_capacity = %d)", |
5688 | group->sgc->capacity); | |
381512cf | 5689 | } |
1da177e4 | 5690 | |
4dcf6aff IM |
5691 | group = group->next; |
5692 | } while (group != sd->groups); | |
3df0fc5b | 5693 | printk(KERN_CONT "\n"); |
1da177e4 | 5694 | |
758b2cdc | 5695 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
3df0fc5b | 5696 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
1da177e4 | 5697 | |
758b2cdc RR |
5698 | if (sd->parent && |
5699 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) | |
3df0fc5b PZ |
5700 | printk(KERN_ERR "ERROR: parent span is not a superset " |
5701 | "of domain->span\n"); | |
4dcf6aff IM |
5702 | return 0; |
5703 | } | |
1da177e4 | 5704 | |
4dcf6aff IM |
5705 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5706 | { | |
5707 | int level = 0; | |
1da177e4 | 5708 | |
d039ac60 | 5709 | if (!sched_debug_enabled) |
f6630114 MT |
5710 | return; |
5711 | ||
4dcf6aff IM |
5712 | if (!sd) { |
5713 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5714 | return; | |
5715 | } | |
1da177e4 | 5716 | |
4dcf6aff IM |
5717 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5718 | ||
5719 | for (;;) { | |
4cb98839 | 5720 | if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) |
4dcf6aff | 5721 | break; |
1da177e4 LT |
5722 | level++; |
5723 | sd = sd->parent; | |
33859f7f | 5724 | if (!sd) |
4dcf6aff IM |
5725 | break; |
5726 | } | |
1da177e4 | 5727 | } |
6d6bc0ad | 5728 | #else /* !CONFIG_SCHED_DEBUG */ |
48f24c4d | 5729 | # define sched_domain_debug(sd, cpu) do { } while (0) |
d039ac60 PZ |
5730 | static inline bool sched_debug(void) |
5731 | { | |
5732 | return false; | |
5733 | } | |
6d6bc0ad | 5734 | #endif /* CONFIG_SCHED_DEBUG */ |
1da177e4 | 5735 | |
1a20ff27 | 5736 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 | 5737 | { |
758b2cdc | 5738 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
245af2c7 SS |
5739 | return 1; |
5740 | ||
5741 | /* Following flags need at least 2 groups */ | |
5742 | if (sd->flags & (SD_LOAD_BALANCE | | |
5743 | SD_BALANCE_NEWIDLE | | |
5744 | SD_BALANCE_FORK | | |
89c4710e | 5745 | SD_BALANCE_EXEC | |
5d4dfddd | 5746 | SD_SHARE_CPUCAPACITY | |
1f6e6c7c | 5747 | SD_ASYM_CPUCAPACITY | |
d77b3ed5 VG |
5748 | SD_SHARE_PKG_RESOURCES | |
5749 | SD_SHARE_POWERDOMAIN)) { | |
245af2c7 SS |
5750 | if (sd->groups != sd->groups->next) |
5751 | return 0; | |
5752 | } | |
5753 | ||
5754 | /* Following flags don't use groups */ | |
c88d5910 | 5755 | if (sd->flags & (SD_WAKE_AFFINE)) |
245af2c7 SS |
5756 | return 0; |
5757 | ||
5758 | return 1; | |
5759 | } | |
5760 | ||
48f24c4d IM |
5761 | static int |
5762 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5763 | { |
5764 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5765 | ||
5766 | if (sd_degenerate(parent)) | |
5767 | return 1; | |
5768 | ||
758b2cdc | 5769 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
245af2c7 SS |
5770 | return 0; |
5771 | ||
245af2c7 SS |
5772 | /* Flags needing groups don't count if only 1 group in parent */ |
5773 | if (parent->groups == parent->groups->next) { | |
5774 | pflags &= ~(SD_LOAD_BALANCE | | |
5775 | SD_BALANCE_NEWIDLE | | |
5776 | SD_BALANCE_FORK | | |
89c4710e | 5777 | SD_BALANCE_EXEC | |
1f6e6c7c | 5778 | SD_ASYM_CPUCAPACITY | |
5d4dfddd | 5779 | SD_SHARE_CPUCAPACITY | |
10866e62 | 5780 | SD_SHARE_PKG_RESOURCES | |
d77b3ed5 VG |
5781 | SD_PREFER_SIBLING | |
5782 | SD_SHARE_POWERDOMAIN); | |
5436499e KC |
5783 | if (nr_node_ids == 1) |
5784 | pflags &= ~SD_SERIALIZE; | |
245af2c7 SS |
5785 | } |
5786 | if (~cflags & pflags) | |
5787 | return 0; | |
5788 | ||
5789 | return 1; | |
5790 | } | |
5791 | ||
dce840a0 | 5792 | static void free_rootdomain(struct rcu_head *rcu) |
c6c4927b | 5793 | { |
dce840a0 | 5794 | struct root_domain *rd = container_of(rcu, struct root_domain, rcu); |
047106ad | 5795 | |
68e74568 | 5796 | cpupri_cleanup(&rd->cpupri); |
6bfd6d72 | 5797 | cpudl_cleanup(&rd->cpudl); |
1baca4ce | 5798 | free_cpumask_var(rd->dlo_mask); |
c6c4927b RR |
5799 | free_cpumask_var(rd->rto_mask); |
5800 | free_cpumask_var(rd->online); | |
5801 | free_cpumask_var(rd->span); | |
5802 | kfree(rd); | |
5803 | } | |
5804 | ||
57d885fe GH |
5805 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
5806 | { | |
a0490fa3 | 5807 | struct root_domain *old_rd = NULL; |
57d885fe | 5808 | unsigned long flags; |
57d885fe | 5809 | |
05fa785c | 5810 | raw_spin_lock_irqsave(&rq->lock, flags); |
57d885fe GH |
5811 | |
5812 | if (rq->rd) { | |
a0490fa3 | 5813 | old_rd = rq->rd; |
57d885fe | 5814 | |
c6c4927b | 5815 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
1f11eb6a | 5816 | set_rq_offline(rq); |
57d885fe | 5817 | |
c6c4927b | 5818 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
dc938520 | 5819 | |
a0490fa3 | 5820 | /* |
0515973f | 5821 | * If we dont want to free the old_rd yet then |
a0490fa3 IM |
5822 | * set old_rd to NULL to skip the freeing later |
5823 | * in this function: | |
5824 | */ | |
5825 | if (!atomic_dec_and_test(&old_rd->refcount)) | |
5826 | old_rd = NULL; | |
57d885fe GH |
5827 | } |
5828 | ||
5829 | atomic_inc(&rd->refcount); | |
5830 | rq->rd = rd; | |
5831 | ||
c6c4927b | 5832 | cpumask_set_cpu(rq->cpu, rd->span); |
00aec93d | 5833 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
1f11eb6a | 5834 | set_rq_online(rq); |
57d885fe | 5835 | |
05fa785c | 5836 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
a0490fa3 IM |
5837 | |
5838 | if (old_rd) | |
dce840a0 | 5839 | call_rcu_sched(&old_rd->rcu, free_rootdomain); |
57d885fe GH |
5840 | } |
5841 | ||
68c38fc3 | 5842 | static int init_rootdomain(struct root_domain *rd) |
57d885fe GH |
5843 | { |
5844 | memset(rd, 0, sizeof(*rd)); | |
5845 | ||
8295c699 | 5846 | if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) |
0c910d28 | 5847 | goto out; |
8295c699 | 5848 | if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) |
c6c4927b | 5849 | goto free_span; |
8295c699 | 5850 | if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) |
c6c4927b | 5851 | goto free_online; |
8295c699 | 5852 | if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) |
1baca4ce | 5853 | goto free_dlo_mask; |
6e0534f2 | 5854 | |
332ac17e | 5855 | init_dl_bw(&rd->dl_bw); |
6bfd6d72 JL |
5856 | if (cpudl_init(&rd->cpudl) != 0) |
5857 | goto free_dlo_mask; | |
332ac17e | 5858 | |
68c38fc3 | 5859 | if (cpupri_init(&rd->cpupri) != 0) |
68e74568 | 5860 | goto free_rto_mask; |
c6c4927b | 5861 | return 0; |
6e0534f2 | 5862 | |
68e74568 RR |
5863 | free_rto_mask: |
5864 | free_cpumask_var(rd->rto_mask); | |
1baca4ce JL |
5865 | free_dlo_mask: |
5866 | free_cpumask_var(rd->dlo_mask); | |
c6c4927b RR |
5867 | free_online: |
5868 | free_cpumask_var(rd->online); | |
5869 | free_span: | |
5870 | free_cpumask_var(rd->span); | |
0c910d28 | 5871 | out: |
c6c4927b | 5872 | return -ENOMEM; |
57d885fe GH |
5873 | } |
5874 | ||
029632fb PZ |
5875 | /* |
5876 | * By default the system creates a single root-domain with all cpus as | |
5877 | * members (mimicking the global state we have today). | |
5878 | */ | |
5879 | struct root_domain def_root_domain; | |
5880 | ||
57d885fe GH |
5881 | static void init_defrootdomain(void) |
5882 | { | |
68c38fc3 | 5883 | init_rootdomain(&def_root_domain); |
c6c4927b | 5884 | |
57d885fe GH |
5885 | atomic_set(&def_root_domain.refcount, 1); |
5886 | } | |
5887 | ||
dc938520 | 5888 | static struct root_domain *alloc_rootdomain(void) |
57d885fe GH |
5889 | { |
5890 | struct root_domain *rd; | |
5891 | ||
5892 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); | |
5893 | if (!rd) | |
5894 | return NULL; | |
5895 | ||
68c38fc3 | 5896 | if (init_rootdomain(rd) != 0) { |
c6c4927b RR |
5897 | kfree(rd); |
5898 | return NULL; | |
5899 | } | |
57d885fe GH |
5900 | |
5901 | return rd; | |
5902 | } | |
5903 | ||
63b2ca30 | 5904 | static void free_sched_groups(struct sched_group *sg, int free_sgc) |
e3589f6c PZ |
5905 | { |
5906 | struct sched_group *tmp, *first; | |
5907 | ||
5908 | if (!sg) | |
5909 | return; | |
5910 | ||
5911 | first = sg; | |
5912 | do { | |
5913 | tmp = sg->next; | |
5914 | ||
63b2ca30 NP |
5915 | if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) |
5916 | kfree(sg->sgc); | |
e3589f6c PZ |
5917 | |
5918 | kfree(sg); | |
5919 | sg = tmp; | |
5920 | } while (sg != first); | |
5921 | } | |
5922 | ||
dce840a0 PZ |
5923 | static void free_sched_domain(struct rcu_head *rcu) |
5924 | { | |
5925 | struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); | |
e3589f6c PZ |
5926 | |
5927 | /* | |
5928 | * If its an overlapping domain it has private groups, iterate and | |
5929 | * nuke them all. | |
5930 | */ | |
5931 | if (sd->flags & SD_OVERLAP) { | |
5932 | free_sched_groups(sd->groups, 1); | |
5933 | } else if (atomic_dec_and_test(&sd->groups->ref)) { | |
63b2ca30 | 5934 | kfree(sd->groups->sgc); |
dce840a0 | 5935 | kfree(sd->groups); |
9c3f75cb | 5936 | } |
dce840a0 PZ |
5937 | kfree(sd); |
5938 | } | |
5939 | ||
5940 | static void destroy_sched_domain(struct sched_domain *sd, int cpu) | |
5941 | { | |
5942 | call_rcu(&sd->rcu, free_sched_domain); | |
5943 | } | |
5944 | ||
5945 | static void destroy_sched_domains(struct sched_domain *sd, int cpu) | |
5946 | { | |
5947 | for (; sd; sd = sd->parent) | |
5948 | destroy_sched_domain(sd, cpu); | |
5949 | } | |
5950 | ||
518cd623 PZ |
5951 | /* |
5952 | * Keep a special pointer to the highest sched_domain that has | |
5953 | * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this | |
5954 | * allows us to avoid some pointer chasing select_idle_sibling(). | |
5955 | * | |
5956 | * Also keep a unique ID per domain (we use the first cpu number in | |
5957 | * the cpumask of the domain), this allows us to quickly tell if | |
39be3501 | 5958 | * two cpus are in the same cache domain, see cpus_share_cache(). |
518cd623 PZ |
5959 | */ |
5960 | DEFINE_PER_CPU(struct sched_domain *, sd_llc); | |
7d9ffa89 | 5961 | DEFINE_PER_CPU(int, sd_llc_size); |
518cd623 | 5962 | DEFINE_PER_CPU(int, sd_llc_id); |
fb13c7ee | 5963 | DEFINE_PER_CPU(struct sched_domain *, sd_numa); |
37dc6b50 PM |
5964 | DEFINE_PER_CPU(struct sched_domain *, sd_busy); |
5965 | DEFINE_PER_CPU(struct sched_domain *, sd_asym); | |
518cd623 PZ |
5966 | |
5967 | static void update_top_cache_domain(int cpu) | |
5968 | { | |
5969 | struct sched_domain *sd; | |
5d4cf996 | 5970 | struct sched_domain *busy_sd = NULL; |
518cd623 | 5971 | int id = cpu; |
7d9ffa89 | 5972 | int size = 1; |
518cd623 PZ |
5973 | |
5974 | sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); | |
7d9ffa89 | 5975 | if (sd) { |
518cd623 | 5976 | id = cpumask_first(sched_domain_span(sd)); |
7d9ffa89 | 5977 | size = cpumask_weight(sched_domain_span(sd)); |
5d4cf996 | 5978 | busy_sd = sd->parent; /* sd_busy */ |
7d9ffa89 | 5979 | } |
5d4cf996 | 5980 | rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); |
518cd623 PZ |
5981 | |
5982 | rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); | |
7d9ffa89 | 5983 | per_cpu(sd_llc_size, cpu) = size; |
518cd623 | 5984 | per_cpu(sd_llc_id, cpu) = id; |
fb13c7ee MG |
5985 | |
5986 | sd = lowest_flag_domain(cpu, SD_NUMA); | |
5987 | rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); | |
37dc6b50 PM |
5988 | |
5989 | sd = highest_flag_domain(cpu, SD_ASYM_PACKING); | |
5990 | rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); | |
518cd623 PZ |
5991 | } |
5992 | ||
1da177e4 | 5993 | /* |
0eab9146 | 5994 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
1da177e4 LT |
5995 | * hold the hotplug lock. |
5996 | */ | |
0eab9146 IM |
5997 | static void |
5998 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) | |
1da177e4 | 5999 | { |
70b97a7f | 6000 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
6001 | struct sched_domain *tmp; |
6002 | ||
6003 | /* Remove the sched domains which do not contribute to scheduling. */ | |
f29c9b1c | 6004 | for (tmp = sd; tmp; ) { |
245af2c7 SS |
6005 | struct sched_domain *parent = tmp->parent; |
6006 | if (!parent) | |
6007 | break; | |
f29c9b1c | 6008 | |
1a848870 | 6009 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 6010 | tmp->parent = parent->parent; |
1a848870 SS |
6011 | if (parent->parent) |
6012 | parent->parent->child = tmp; | |
10866e62 PZ |
6013 | /* |
6014 | * Transfer SD_PREFER_SIBLING down in case of a | |
6015 | * degenerate parent; the spans match for this | |
6016 | * so the property transfers. | |
6017 | */ | |
6018 | if (parent->flags & SD_PREFER_SIBLING) | |
6019 | tmp->flags |= SD_PREFER_SIBLING; | |
dce840a0 | 6020 | destroy_sched_domain(parent, cpu); |
f29c9b1c LZ |
6021 | } else |
6022 | tmp = tmp->parent; | |
245af2c7 SS |
6023 | } |
6024 | ||
1a848870 | 6025 | if (sd && sd_degenerate(sd)) { |
dce840a0 | 6026 | tmp = sd; |
245af2c7 | 6027 | sd = sd->parent; |
dce840a0 | 6028 | destroy_sched_domain(tmp, cpu); |
1a848870 SS |
6029 | if (sd) |
6030 | sd->child = NULL; | |
6031 | } | |
1da177e4 | 6032 | |
4cb98839 | 6033 | sched_domain_debug(sd, cpu); |
1da177e4 | 6034 | |
57d885fe | 6035 | rq_attach_root(rq, rd); |
dce840a0 | 6036 | tmp = rq->sd; |
674311d5 | 6037 | rcu_assign_pointer(rq->sd, sd); |
dce840a0 | 6038 | destroy_sched_domains(tmp, cpu); |
518cd623 PZ |
6039 | |
6040 | update_top_cache_domain(cpu); | |
1da177e4 LT |
6041 | } |
6042 | ||
1da177e4 LT |
6043 | /* Setup the mask of cpus configured for isolated domains */ |
6044 | static int __init isolated_cpu_setup(char *str) | |
6045 | { | |
a6e4491c PB |
6046 | int ret; |
6047 | ||
bdddd296 | 6048 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
a6e4491c PB |
6049 | ret = cpulist_parse(str, cpu_isolated_map); |
6050 | if (ret) { | |
6051 | pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids); | |
6052 | return 0; | |
6053 | } | |
1da177e4 LT |
6054 | return 1; |
6055 | } | |
8927f494 | 6056 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 | 6057 | |
49a02c51 | 6058 | struct s_data { |
21d42ccf | 6059 | struct sched_domain ** __percpu sd; |
49a02c51 AH |
6060 | struct root_domain *rd; |
6061 | }; | |
6062 | ||
2109b99e | 6063 | enum s_alloc { |
2109b99e | 6064 | sa_rootdomain, |
21d42ccf | 6065 | sa_sd, |
dce840a0 | 6066 | sa_sd_storage, |
2109b99e AH |
6067 | sa_none, |
6068 | }; | |
6069 | ||
c1174876 PZ |
6070 | /* |
6071 | * Build an iteration mask that can exclude certain CPUs from the upwards | |
6072 | * domain traversal. | |
6073 | * | |
6074 | * Asymmetric node setups can result in situations where the domain tree is of | |
6075 | * unequal depth, make sure to skip domains that already cover the entire | |
6076 | * range. | |
6077 | * | |
6078 | * In that case build_sched_domains() will have terminated the iteration early | |
6079 | * and our sibling sd spans will be empty. Domains should always include the | |
6080 | * cpu they're built on, so check that. | |
6081 | * | |
6082 | */ | |
6083 | static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) | |
6084 | { | |
6085 | const struct cpumask *span = sched_domain_span(sd); | |
6086 | struct sd_data *sdd = sd->private; | |
6087 | struct sched_domain *sibling; | |
6088 | int i; | |
6089 | ||
6090 | for_each_cpu(i, span) { | |
6091 | sibling = *per_cpu_ptr(sdd->sd, i); | |
6092 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) | |
6093 | continue; | |
6094 | ||
6095 | cpumask_set_cpu(i, sched_group_mask(sg)); | |
6096 | } | |
6097 | } | |
6098 | ||
6099 | /* | |
6100 | * Return the canonical balance cpu for this group, this is the first cpu | |
6101 | * of this group that's also in the iteration mask. | |
6102 | */ | |
6103 | int group_balance_cpu(struct sched_group *sg) | |
6104 | { | |
6105 | return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); | |
6106 | } | |
6107 | ||
e3589f6c PZ |
6108 | static int |
6109 | build_overlap_sched_groups(struct sched_domain *sd, int cpu) | |
6110 | { | |
6111 | struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; | |
6112 | const struct cpumask *span = sched_domain_span(sd); | |
6113 | struct cpumask *covered = sched_domains_tmpmask; | |
6114 | struct sd_data *sdd = sd->private; | |
aaecac4a | 6115 | struct sched_domain *sibling; |
e3589f6c PZ |
6116 | int i; |
6117 | ||
6118 | cpumask_clear(covered); | |
6119 | ||
6120 | for_each_cpu(i, span) { | |
6121 | struct cpumask *sg_span; | |
6122 | ||
6123 | if (cpumask_test_cpu(i, covered)) | |
6124 | continue; | |
6125 | ||
aaecac4a | 6126 | sibling = *per_cpu_ptr(sdd->sd, i); |
c1174876 PZ |
6127 | |
6128 | /* See the comment near build_group_mask(). */ | |
aaecac4a | 6129 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) |
c1174876 PZ |
6130 | continue; |
6131 | ||
e3589f6c | 6132 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), |
4d78a223 | 6133 | GFP_KERNEL, cpu_to_node(cpu)); |
e3589f6c PZ |
6134 | |
6135 | if (!sg) | |
6136 | goto fail; | |
6137 | ||
6138 | sg_span = sched_group_cpus(sg); | |
aaecac4a ZZ |
6139 | if (sibling->child) |
6140 | cpumask_copy(sg_span, sched_domain_span(sibling->child)); | |
6141 | else | |
e3589f6c PZ |
6142 | cpumask_set_cpu(i, sg_span); |
6143 | ||
6144 | cpumask_or(covered, covered, sg_span); | |
6145 | ||
63b2ca30 NP |
6146 | sg->sgc = *per_cpu_ptr(sdd->sgc, i); |
6147 | if (atomic_inc_return(&sg->sgc->ref) == 1) | |
c1174876 PZ |
6148 | build_group_mask(sd, sg); |
6149 | ||
c3decf0d | 6150 | /* |
63b2ca30 | 6151 | * Initialize sgc->capacity such that even if we mess up the |
c3decf0d PZ |
6152 | * domains and no possible iteration will get us here, we won't |
6153 | * die on a /0 trap. | |
6154 | */ | |
ca8ce3d0 | 6155 | sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); |
e3589f6c | 6156 | |
c1174876 PZ |
6157 | /* |
6158 | * Make sure the first group of this domain contains the | |
6159 | * canonical balance cpu. Otherwise the sched_domain iteration | |
6160 | * breaks. See update_sg_lb_stats(). | |
6161 | */ | |
74a5ce20 | 6162 | if ((!groups && cpumask_test_cpu(cpu, sg_span)) || |
c1174876 | 6163 | group_balance_cpu(sg) == cpu) |
e3589f6c PZ |
6164 | groups = sg; |
6165 | ||
6166 | if (!first) | |
6167 | first = sg; | |
6168 | if (last) | |
6169 | last->next = sg; | |
6170 | last = sg; | |
6171 | last->next = first; | |
6172 | } | |
6173 | sd->groups = groups; | |
6174 | ||
6175 | return 0; | |
6176 | ||
6177 | fail: | |
6178 | free_sched_groups(first, 0); | |
6179 | ||
6180 | return -ENOMEM; | |
6181 | } | |
6182 | ||
dce840a0 | 6183 | static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) |
1da177e4 | 6184 | { |
dce840a0 PZ |
6185 | struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); |
6186 | struct sched_domain *child = sd->child; | |
1da177e4 | 6187 | |
dce840a0 PZ |
6188 | if (child) |
6189 | cpu = cpumask_first(sched_domain_span(child)); | |
1e9f28fa | 6190 | |
9c3f75cb | 6191 | if (sg) { |
dce840a0 | 6192 | *sg = *per_cpu_ptr(sdd->sg, cpu); |
63b2ca30 NP |
6193 | (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); |
6194 | atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ | |
9c3f75cb | 6195 | } |
dce840a0 PZ |
6196 | |
6197 | return cpu; | |
1e9f28fa | 6198 | } |
1e9f28fa | 6199 | |
01a08546 | 6200 | /* |
dce840a0 PZ |
6201 | * build_sched_groups will build a circular linked list of the groups |
6202 | * covered by the given span, and will set each group's ->cpumask correctly, | |
ced549fa | 6203 | * and ->cpu_capacity to 0. |
e3589f6c PZ |
6204 | * |
6205 | * Assumes the sched_domain tree is fully constructed | |
01a08546 | 6206 | */ |
e3589f6c PZ |
6207 | static int |
6208 | build_sched_groups(struct sched_domain *sd, int cpu) | |
1da177e4 | 6209 | { |
dce840a0 PZ |
6210 | struct sched_group *first = NULL, *last = NULL; |
6211 | struct sd_data *sdd = sd->private; | |
6212 | const struct cpumask *span = sched_domain_span(sd); | |
f96225fd | 6213 | struct cpumask *covered; |
dce840a0 | 6214 | int i; |
9c1cfda2 | 6215 | |
e3589f6c PZ |
6216 | get_group(cpu, sdd, &sd->groups); |
6217 | atomic_inc(&sd->groups->ref); | |
6218 | ||
0936629f | 6219 | if (cpu != cpumask_first(span)) |
e3589f6c PZ |
6220 | return 0; |
6221 | ||
f96225fd PZ |
6222 | lockdep_assert_held(&sched_domains_mutex); |
6223 | covered = sched_domains_tmpmask; | |
6224 | ||
dce840a0 | 6225 | cpumask_clear(covered); |
6711cab4 | 6226 | |
dce840a0 PZ |
6227 | for_each_cpu(i, span) { |
6228 | struct sched_group *sg; | |
cd08e923 | 6229 | int group, j; |
6711cab4 | 6230 | |
dce840a0 PZ |
6231 | if (cpumask_test_cpu(i, covered)) |
6232 | continue; | |
6711cab4 | 6233 | |
cd08e923 | 6234 | group = get_group(i, sdd, &sg); |
c1174876 | 6235 | cpumask_setall(sched_group_mask(sg)); |
0601a88d | 6236 | |
dce840a0 PZ |
6237 | for_each_cpu(j, span) { |
6238 | if (get_group(j, sdd, NULL) != group) | |
6239 | continue; | |
0601a88d | 6240 | |
dce840a0 PZ |
6241 | cpumask_set_cpu(j, covered); |
6242 | cpumask_set_cpu(j, sched_group_cpus(sg)); | |
6243 | } | |
0601a88d | 6244 | |
dce840a0 PZ |
6245 | if (!first) |
6246 | first = sg; | |
6247 | if (last) | |
6248 | last->next = sg; | |
6249 | last = sg; | |
6250 | } | |
6251 | last->next = first; | |
e3589f6c PZ |
6252 | |
6253 | return 0; | |
0601a88d | 6254 | } |
51888ca2 | 6255 | |
89c4710e | 6256 | /* |
63b2ca30 | 6257 | * Initialize sched groups cpu_capacity. |
89c4710e | 6258 | * |
63b2ca30 | 6259 | * cpu_capacity indicates the capacity of sched group, which is used while |
89c4710e | 6260 | * distributing the load between different sched groups in a sched domain. |
63b2ca30 NP |
6261 | * Typically cpu_capacity for all the groups in a sched domain will be same |
6262 | * unless there are asymmetries in the topology. If there are asymmetries, | |
6263 | * group having more cpu_capacity will pickup more load compared to the | |
6264 | * group having less cpu_capacity. | |
89c4710e | 6265 | */ |
63b2ca30 | 6266 | static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) |
89c4710e | 6267 | { |
e3589f6c | 6268 | struct sched_group *sg = sd->groups; |
89c4710e | 6269 | |
94c95ba6 | 6270 | WARN_ON(!sg); |
e3589f6c PZ |
6271 | |
6272 | do { | |
6273 | sg->group_weight = cpumask_weight(sched_group_cpus(sg)); | |
6274 | sg = sg->next; | |
6275 | } while (sg != sd->groups); | |
89c4710e | 6276 | |
c1174876 | 6277 | if (cpu != group_balance_cpu(sg)) |
e3589f6c | 6278 | return; |
aae6d3dd | 6279 | |
63b2ca30 NP |
6280 | update_group_capacity(sd, cpu); |
6281 | atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); | |
89c4710e SS |
6282 | } |
6283 | ||
7c16ec58 MT |
6284 | /* |
6285 | * Initializers for schedule domains | |
6286 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() | |
6287 | */ | |
6288 | ||
1d3504fc | 6289 | static int default_relax_domain_level = -1; |
60495e77 | 6290 | int sched_domain_level_max; |
1d3504fc HS |
6291 | |
6292 | static int __init setup_relax_domain_level(char *str) | |
6293 | { | |
a841f8ce DS |
6294 | if (kstrtoint(str, 0, &default_relax_domain_level)) |
6295 | pr_warn("Unable to set relax_domain_level\n"); | |
30e0e178 | 6296 | |
1d3504fc HS |
6297 | return 1; |
6298 | } | |
6299 | __setup("relax_domain_level=", setup_relax_domain_level); | |
6300 | ||
6301 | static void set_domain_attribute(struct sched_domain *sd, | |
6302 | struct sched_domain_attr *attr) | |
6303 | { | |
6304 | int request; | |
6305 | ||
6306 | if (!attr || attr->relax_domain_level < 0) { | |
6307 | if (default_relax_domain_level < 0) | |
6308 | return; | |
6309 | else | |
6310 | request = default_relax_domain_level; | |
6311 | } else | |
6312 | request = attr->relax_domain_level; | |
6313 | if (request < sd->level) { | |
6314 | /* turn off idle balance on this domain */ | |
c88d5910 | 6315 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
6316 | } else { |
6317 | /* turn on idle balance on this domain */ | |
c88d5910 | 6318 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
6319 | } |
6320 | } | |
6321 | ||
54ab4ff4 PZ |
6322 | static void __sdt_free(const struct cpumask *cpu_map); |
6323 | static int __sdt_alloc(const struct cpumask *cpu_map); | |
6324 | ||
2109b99e AH |
6325 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
6326 | const struct cpumask *cpu_map) | |
6327 | { | |
6328 | switch (what) { | |
2109b99e | 6329 | case sa_rootdomain: |
822ff793 PZ |
6330 | if (!atomic_read(&d->rd->refcount)) |
6331 | free_rootdomain(&d->rd->rcu); /* fall through */ | |
21d42ccf PZ |
6332 | case sa_sd: |
6333 | free_percpu(d->sd); /* fall through */ | |
dce840a0 | 6334 | case sa_sd_storage: |
54ab4ff4 | 6335 | __sdt_free(cpu_map); /* fall through */ |
2109b99e AH |
6336 | case sa_none: |
6337 | break; | |
6338 | } | |
6339 | } | |
3404c8d9 | 6340 | |
2109b99e AH |
6341 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
6342 | const struct cpumask *cpu_map) | |
6343 | { | |
dce840a0 PZ |
6344 | memset(d, 0, sizeof(*d)); |
6345 | ||
54ab4ff4 PZ |
6346 | if (__sdt_alloc(cpu_map)) |
6347 | return sa_sd_storage; | |
dce840a0 PZ |
6348 | d->sd = alloc_percpu(struct sched_domain *); |
6349 | if (!d->sd) | |
6350 | return sa_sd_storage; | |
2109b99e | 6351 | d->rd = alloc_rootdomain(); |
dce840a0 | 6352 | if (!d->rd) |
21d42ccf | 6353 | return sa_sd; |
2109b99e AH |
6354 | return sa_rootdomain; |
6355 | } | |
57d885fe | 6356 | |
dce840a0 PZ |
6357 | /* |
6358 | * NULL the sd_data elements we've used to build the sched_domain and | |
6359 | * sched_group structure so that the subsequent __free_domain_allocs() | |
6360 | * will not free the data we're using. | |
6361 | */ | |
6362 | static void claim_allocations(int cpu, struct sched_domain *sd) | |
6363 | { | |
6364 | struct sd_data *sdd = sd->private; | |
dce840a0 PZ |
6365 | |
6366 | WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); | |
6367 | *per_cpu_ptr(sdd->sd, cpu) = NULL; | |
6368 | ||
e3589f6c | 6369 | if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) |
dce840a0 | 6370 | *per_cpu_ptr(sdd->sg, cpu) = NULL; |
e3589f6c | 6371 | |
63b2ca30 NP |
6372 | if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) |
6373 | *per_cpu_ptr(sdd->sgc, cpu) = NULL; | |
dce840a0 PZ |
6374 | } |
6375 | ||
cb83b629 | 6376 | #ifdef CONFIG_NUMA |
cb83b629 | 6377 | static int sched_domains_numa_levels; |
e3fe70b1 | 6378 | enum numa_topology_type sched_numa_topology_type; |
cb83b629 | 6379 | static int *sched_domains_numa_distance; |
9942f79b | 6380 | int sched_max_numa_distance; |
cb83b629 PZ |
6381 | static struct cpumask ***sched_domains_numa_masks; |
6382 | static int sched_domains_curr_level; | |
143e1e28 | 6383 | #endif |
cb83b629 | 6384 | |
143e1e28 VG |
6385 | /* |
6386 | * SD_flags allowed in topology descriptions. | |
6387 | * | |
94f438c8 PZ |
6388 | * These flags are purely descriptive of the topology and do not prescribe |
6389 | * behaviour. Behaviour is artificial and mapped in the below sd_init() | |
6390 | * function: | |
143e1e28 | 6391 | * |
94f438c8 PZ |
6392 | * SD_SHARE_CPUCAPACITY - describes SMT topologies |
6393 | * SD_SHARE_PKG_RESOURCES - describes shared caches | |
6394 | * SD_NUMA - describes NUMA topologies | |
6395 | * SD_SHARE_POWERDOMAIN - describes shared power domain | |
1f6e6c7c | 6396 | * SD_ASYM_CPUCAPACITY - describes mixed capacity topologies |
94f438c8 PZ |
6397 | * |
6398 | * Odd one out, which beside describing the topology has a quirk also | |
6399 | * prescribes the desired behaviour that goes along with it: | |
6400 | * | |
6401 | * SD_ASYM_PACKING - describes SMT quirks | |
143e1e28 VG |
6402 | */ |
6403 | #define TOPOLOGY_SD_FLAGS \ | |
5d4dfddd | 6404 | (SD_SHARE_CPUCAPACITY | \ |
143e1e28 VG |
6405 | SD_SHARE_PKG_RESOURCES | \ |
6406 | SD_NUMA | \ | |
d77b3ed5 | 6407 | SD_ASYM_PACKING | \ |
1f6e6c7c | 6408 | SD_ASYM_CPUCAPACITY | \ |
d77b3ed5 | 6409 | SD_SHARE_POWERDOMAIN) |
cb83b629 PZ |
6410 | |
6411 | static struct sched_domain * | |
3676b13e MR |
6412 | sd_init(struct sched_domain_topology_level *tl, |
6413 | struct sched_domain *child, int cpu) | |
cb83b629 PZ |
6414 | { |
6415 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); | |
143e1e28 VG |
6416 | int sd_weight, sd_flags = 0; |
6417 | ||
6418 | #ifdef CONFIG_NUMA | |
6419 | /* | |
6420 | * Ugly hack to pass state to sd_numa_mask()... | |
6421 | */ | |
6422 | sched_domains_curr_level = tl->numa_level; | |
6423 | #endif | |
6424 | ||
6425 | sd_weight = cpumask_weight(tl->mask(cpu)); | |
6426 | ||
6427 | if (tl->sd_flags) | |
6428 | sd_flags = (*tl->sd_flags)(); | |
6429 | if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, | |
6430 | "wrong sd_flags in topology description\n")) | |
6431 | sd_flags &= ~TOPOLOGY_SD_FLAGS; | |
cb83b629 PZ |
6432 | |
6433 | *sd = (struct sched_domain){ | |
6434 | .min_interval = sd_weight, | |
6435 | .max_interval = 2*sd_weight, | |
6436 | .busy_factor = 32, | |
870a0bb5 | 6437 | .imbalance_pct = 125, |
143e1e28 VG |
6438 | |
6439 | .cache_nice_tries = 0, | |
6440 | .busy_idx = 0, | |
6441 | .idle_idx = 0, | |
cb83b629 PZ |
6442 | .newidle_idx = 0, |
6443 | .wake_idx = 0, | |
6444 | .forkexec_idx = 0, | |
6445 | ||
6446 | .flags = 1*SD_LOAD_BALANCE | |
6447 | | 1*SD_BALANCE_NEWIDLE | |
143e1e28 VG |
6448 | | 1*SD_BALANCE_EXEC |
6449 | | 1*SD_BALANCE_FORK | |
cb83b629 | 6450 | | 0*SD_BALANCE_WAKE |
143e1e28 | 6451 | | 1*SD_WAKE_AFFINE |
5d4dfddd | 6452 | | 0*SD_SHARE_CPUCAPACITY |
cb83b629 | 6453 | | 0*SD_SHARE_PKG_RESOURCES |
143e1e28 | 6454 | | 0*SD_SERIALIZE |
cb83b629 | 6455 | | 0*SD_PREFER_SIBLING |
143e1e28 VG |
6456 | | 0*SD_NUMA |
6457 | | sd_flags | |
cb83b629 | 6458 | , |
143e1e28 | 6459 | |
cb83b629 PZ |
6460 | .last_balance = jiffies, |
6461 | .balance_interval = sd_weight, | |
143e1e28 | 6462 | .smt_gain = 0, |
2b4cfe64 JL |
6463 | .max_newidle_lb_cost = 0, |
6464 | .next_decay_max_lb_cost = jiffies, | |
3676b13e | 6465 | .child = child, |
143e1e28 VG |
6466 | #ifdef CONFIG_SCHED_DEBUG |
6467 | .name = tl->name, | |
6468 | #endif | |
cb83b629 | 6469 | }; |
cb83b629 PZ |
6470 | |
6471 | /* | |
143e1e28 | 6472 | * Convert topological properties into behaviour. |
cb83b629 | 6473 | */ |
143e1e28 | 6474 | |
9ee1cda5 MR |
6475 | if (sd->flags & SD_ASYM_CPUCAPACITY) { |
6476 | struct sched_domain *t = sd; | |
6477 | ||
6478 | for_each_lower_domain(t) | |
6479 | t->flags |= SD_BALANCE_WAKE; | |
6480 | } | |
6481 | ||
5d4dfddd | 6482 | if (sd->flags & SD_SHARE_CPUCAPACITY) { |
caff37ef | 6483 | sd->flags |= SD_PREFER_SIBLING; |
143e1e28 VG |
6484 | sd->imbalance_pct = 110; |
6485 | sd->smt_gain = 1178; /* ~15% */ | |
143e1e28 VG |
6486 | |
6487 | } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { | |
6488 | sd->imbalance_pct = 117; | |
6489 | sd->cache_nice_tries = 1; | |
6490 | sd->busy_idx = 2; | |
6491 | ||
6492 | #ifdef CONFIG_NUMA | |
6493 | } else if (sd->flags & SD_NUMA) { | |
6494 | sd->cache_nice_tries = 2; | |
6495 | sd->busy_idx = 3; | |
6496 | sd->idle_idx = 2; | |
6497 | ||
6498 | sd->flags |= SD_SERIALIZE; | |
6499 | if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { | |
6500 | sd->flags &= ~(SD_BALANCE_EXEC | | |
6501 | SD_BALANCE_FORK | | |
6502 | SD_WAKE_AFFINE); | |
6503 | } | |
6504 | ||
6505 | #endif | |
6506 | } else { | |
6507 | sd->flags |= SD_PREFER_SIBLING; | |
6508 | sd->cache_nice_tries = 1; | |
6509 | sd->busy_idx = 2; | |
6510 | sd->idle_idx = 1; | |
6511 | } | |
6512 | ||
6513 | sd->private = &tl->data; | |
cb83b629 PZ |
6514 | |
6515 | return sd; | |
6516 | } | |
6517 | ||
143e1e28 VG |
6518 | /* |
6519 | * Topology list, bottom-up. | |
6520 | */ | |
6521 | static struct sched_domain_topology_level default_topology[] = { | |
6522 | #ifdef CONFIG_SCHED_SMT | |
6523 | { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, | |
6524 | #endif | |
6525 | #ifdef CONFIG_SCHED_MC | |
6526 | { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, | |
143e1e28 VG |
6527 | #endif |
6528 | { cpu_cpu_mask, SD_INIT_NAME(DIE) }, | |
6529 | { NULL, }, | |
6530 | }; | |
6531 | ||
c6e1e7b5 JG |
6532 | static struct sched_domain_topology_level *sched_domain_topology = |
6533 | default_topology; | |
143e1e28 VG |
6534 | |
6535 | #define for_each_sd_topology(tl) \ | |
6536 | for (tl = sched_domain_topology; tl->mask; tl++) | |
6537 | ||
6538 | void set_sched_topology(struct sched_domain_topology_level *tl) | |
6539 | { | |
6540 | sched_domain_topology = tl; | |
6541 | } | |
6542 | ||
6543 | #ifdef CONFIG_NUMA | |
6544 | ||
cb83b629 PZ |
6545 | static const struct cpumask *sd_numa_mask(int cpu) |
6546 | { | |
6547 | return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; | |
6548 | } | |
6549 | ||
d039ac60 PZ |
6550 | static void sched_numa_warn(const char *str) |
6551 | { | |
6552 | static int done = false; | |
6553 | int i,j; | |
6554 | ||
6555 | if (done) | |
6556 | return; | |
6557 | ||
6558 | done = true; | |
6559 | ||
6560 | printk(KERN_WARNING "ERROR: %s\n\n", str); | |
6561 | ||
6562 | for (i = 0; i < nr_node_ids; i++) { | |
6563 | printk(KERN_WARNING " "); | |
6564 | for (j = 0; j < nr_node_ids; j++) | |
6565 | printk(KERN_CONT "%02d ", node_distance(i,j)); | |
6566 | printk(KERN_CONT "\n"); | |
6567 | } | |
6568 | printk(KERN_WARNING "\n"); | |
6569 | } | |
6570 | ||
9942f79b | 6571 | bool find_numa_distance(int distance) |
d039ac60 PZ |
6572 | { |
6573 | int i; | |
6574 | ||
6575 | if (distance == node_distance(0, 0)) | |
6576 | return true; | |
6577 | ||
6578 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
6579 | if (sched_domains_numa_distance[i] == distance) | |
6580 | return true; | |
6581 | } | |
6582 | ||
6583 | return false; | |
6584 | } | |
6585 | ||
e3fe70b1 RR |
6586 | /* |
6587 | * A system can have three types of NUMA topology: | |
6588 | * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system | |
6589 | * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes | |
6590 | * NUMA_BACKPLANE: nodes can reach other nodes through a backplane | |
6591 | * | |
6592 | * The difference between a glueless mesh topology and a backplane | |
6593 | * topology lies in whether communication between not directly | |
6594 | * connected nodes goes through intermediary nodes (where programs | |
6595 | * could run), or through backplane controllers. This affects | |
6596 | * placement of programs. | |
6597 | * | |
6598 | * The type of topology can be discerned with the following tests: | |
6599 | * - If the maximum distance between any nodes is 1 hop, the system | |
6600 | * is directly connected. | |
6601 | * - If for two nodes A and B, located N > 1 hops away from each other, | |
6602 | * there is an intermediary node C, which is < N hops away from both | |
6603 | * nodes A and B, the system is a glueless mesh. | |
6604 | */ | |
6605 | static void init_numa_topology_type(void) | |
6606 | { | |
6607 | int a, b, c, n; | |
6608 | ||
6609 | n = sched_max_numa_distance; | |
6610 | ||
e237882b | 6611 | if (sched_domains_numa_levels <= 1) { |
e3fe70b1 | 6612 | sched_numa_topology_type = NUMA_DIRECT; |
e237882b AG |
6613 | return; |
6614 | } | |
e3fe70b1 RR |
6615 | |
6616 | for_each_online_node(a) { | |
6617 | for_each_online_node(b) { | |
6618 | /* Find two nodes furthest removed from each other. */ | |
6619 | if (node_distance(a, b) < n) | |
6620 | continue; | |
6621 | ||
6622 | /* Is there an intermediary node between a and b? */ | |
6623 | for_each_online_node(c) { | |
6624 | if (node_distance(a, c) < n && | |
6625 | node_distance(b, c) < n) { | |
6626 | sched_numa_topology_type = | |
6627 | NUMA_GLUELESS_MESH; | |
6628 | return; | |
6629 | } | |
6630 | } | |
6631 | ||
6632 | sched_numa_topology_type = NUMA_BACKPLANE; | |
6633 | return; | |
6634 | } | |
6635 | } | |
6636 | } | |
6637 | ||
cb83b629 PZ |
6638 | static void sched_init_numa(void) |
6639 | { | |
6640 | int next_distance, curr_distance = node_distance(0, 0); | |
6641 | struct sched_domain_topology_level *tl; | |
6642 | int level = 0; | |
6643 | int i, j, k; | |
6644 | ||
cb83b629 PZ |
6645 | sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); |
6646 | if (!sched_domains_numa_distance) | |
6647 | return; | |
6648 | ||
6649 | /* | |
6650 | * O(nr_nodes^2) deduplicating selection sort -- in order to find the | |
6651 | * unique distances in the node_distance() table. | |
6652 | * | |
6653 | * Assumes node_distance(0,j) includes all distances in | |
6654 | * node_distance(i,j) in order to avoid cubic time. | |
cb83b629 PZ |
6655 | */ |
6656 | next_distance = curr_distance; | |
6657 | for (i = 0; i < nr_node_ids; i++) { | |
6658 | for (j = 0; j < nr_node_ids; j++) { | |
d039ac60 PZ |
6659 | for (k = 0; k < nr_node_ids; k++) { |
6660 | int distance = node_distance(i, k); | |
6661 | ||
6662 | if (distance > curr_distance && | |
6663 | (distance < next_distance || | |
6664 | next_distance == curr_distance)) | |
6665 | next_distance = distance; | |
6666 | ||
6667 | /* | |
6668 | * While not a strong assumption it would be nice to know | |
6669 | * about cases where if node A is connected to B, B is not | |
6670 | * equally connected to A. | |
6671 | */ | |
6672 | if (sched_debug() && node_distance(k, i) != distance) | |
6673 | sched_numa_warn("Node-distance not symmetric"); | |
6674 | ||
6675 | if (sched_debug() && i && !find_numa_distance(distance)) | |
6676 | sched_numa_warn("Node-0 not representative"); | |
6677 | } | |
6678 | if (next_distance != curr_distance) { | |
6679 | sched_domains_numa_distance[level++] = next_distance; | |
6680 | sched_domains_numa_levels = level; | |
6681 | curr_distance = next_distance; | |
6682 | } else break; | |
cb83b629 | 6683 | } |
d039ac60 PZ |
6684 | |
6685 | /* | |
6686 | * In case of sched_debug() we verify the above assumption. | |
6687 | */ | |
6688 | if (!sched_debug()) | |
6689 | break; | |
cb83b629 | 6690 | } |
c123588b AR |
6691 | |
6692 | if (!level) | |
6693 | return; | |
6694 | ||
cb83b629 PZ |
6695 | /* |
6696 | * 'level' contains the number of unique distances, excluding the | |
6697 | * identity distance node_distance(i,i). | |
6698 | * | |
28b4a521 | 6699 | * The sched_domains_numa_distance[] array includes the actual distance |
cb83b629 PZ |
6700 | * numbers. |
6701 | */ | |
6702 | ||
5f7865f3 TC |
6703 | /* |
6704 | * Here, we should temporarily reset sched_domains_numa_levels to 0. | |
6705 | * If it fails to allocate memory for array sched_domains_numa_masks[][], | |
6706 | * the array will contain less then 'level' members. This could be | |
6707 | * dangerous when we use it to iterate array sched_domains_numa_masks[][] | |
6708 | * in other functions. | |
6709 | * | |
6710 | * We reset it to 'level' at the end of this function. | |
6711 | */ | |
6712 | sched_domains_numa_levels = 0; | |
6713 | ||
cb83b629 PZ |
6714 | sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); |
6715 | if (!sched_domains_numa_masks) | |
6716 | return; | |
6717 | ||
6718 | /* | |
6719 | * Now for each level, construct a mask per node which contains all | |
6720 | * cpus of nodes that are that many hops away from us. | |
6721 | */ | |
6722 | for (i = 0; i < level; i++) { | |
6723 | sched_domains_numa_masks[i] = | |
6724 | kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); | |
6725 | if (!sched_domains_numa_masks[i]) | |
6726 | return; | |
6727 | ||
6728 | for (j = 0; j < nr_node_ids; j++) { | |
2ea45800 | 6729 | struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); |
cb83b629 PZ |
6730 | if (!mask) |
6731 | return; | |
6732 | ||
6733 | sched_domains_numa_masks[i][j] = mask; | |
6734 | ||
9c03ee14 | 6735 | for_each_node(k) { |
dd7d8634 | 6736 | if (node_distance(j, k) > sched_domains_numa_distance[i]) |
cb83b629 PZ |
6737 | continue; |
6738 | ||
6739 | cpumask_or(mask, mask, cpumask_of_node(k)); | |
6740 | } | |
6741 | } | |
6742 | } | |
6743 | ||
143e1e28 VG |
6744 | /* Compute default topology size */ |
6745 | for (i = 0; sched_domain_topology[i].mask; i++); | |
6746 | ||
c515db8c | 6747 | tl = kzalloc((i + level + 1) * |
cb83b629 PZ |
6748 | sizeof(struct sched_domain_topology_level), GFP_KERNEL); |
6749 | if (!tl) | |
6750 | return; | |
6751 | ||
6752 | /* | |
6753 | * Copy the default topology bits.. | |
6754 | */ | |
143e1e28 VG |
6755 | for (i = 0; sched_domain_topology[i].mask; i++) |
6756 | tl[i] = sched_domain_topology[i]; | |
cb83b629 PZ |
6757 | |
6758 | /* | |
6759 | * .. and append 'j' levels of NUMA goodness. | |
6760 | */ | |
6761 | for (j = 0; j < level; i++, j++) { | |
6762 | tl[i] = (struct sched_domain_topology_level){ | |
cb83b629 | 6763 | .mask = sd_numa_mask, |
143e1e28 | 6764 | .sd_flags = cpu_numa_flags, |
cb83b629 PZ |
6765 | .flags = SDTL_OVERLAP, |
6766 | .numa_level = j, | |
143e1e28 | 6767 | SD_INIT_NAME(NUMA) |
cb83b629 PZ |
6768 | }; |
6769 | } | |
6770 | ||
6771 | sched_domain_topology = tl; | |
5f7865f3 TC |
6772 | |
6773 | sched_domains_numa_levels = level; | |
9942f79b | 6774 | sched_max_numa_distance = sched_domains_numa_distance[level - 1]; |
e3fe70b1 RR |
6775 | |
6776 | init_numa_topology_type(); | |
cb83b629 | 6777 | } |
301a5cba | 6778 | |
135fb3e1 | 6779 | static void sched_domains_numa_masks_set(unsigned int cpu) |
301a5cba | 6780 | { |
301a5cba | 6781 | int node = cpu_to_node(cpu); |
135fb3e1 | 6782 | int i, j; |
301a5cba TC |
6783 | |
6784 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
6785 | for (j = 0; j < nr_node_ids; j++) { | |
6786 | if (node_distance(j, node) <= sched_domains_numa_distance[i]) | |
6787 | cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); | |
6788 | } | |
6789 | } | |
6790 | } | |
6791 | ||
135fb3e1 | 6792 | static void sched_domains_numa_masks_clear(unsigned int cpu) |
301a5cba TC |
6793 | { |
6794 | int i, j; | |
135fb3e1 | 6795 | |
301a5cba TC |
6796 | for (i = 0; i < sched_domains_numa_levels; i++) { |
6797 | for (j = 0; j < nr_node_ids; j++) | |
6798 | cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); | |
6799 | } | |
6800 | } | |
6801 | ||
cb83b629 | 6802 | #else |
135fb3e1 TG |
6803 | static inline void sched_init_numa(void) { } |
6804 | static void sched_domains_numa_masks_set(unsigned int cpu) { } | |
6805 | static void sched_domains_numa_masks_clear(unsigned int cpu) { } | |
cb83b629 PZ |
6806 | #endif /* CONFIG_NUMA */ |
6807 | ||
54ab4ff4 PZ |
6808 | static int __sdt_alloc(const struct cpumask *cpu_map) |
6809 | { | |
6810 | struct sched_domain_topology_level *tl; | |
6811 | int j; | |
6812 | ||
27723a68 | 6813 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
6814 | struct sd_data *sdd = &tl->data; |
6815 | ||
6816 | sdd->sd = alloc_percpu(struct sched_domain *); | |
6817 | if (!sdd->sd) | |
6818 | return -ENOMEM; | |
6819 | ||
6820 | sdd->sg = alloc_percpu(struct sched_group *); | |
6821 | if (!sdd->sg) | |
6822 | return -ENOMEM; | |
6823 | ||
63b2ca30 NP |
6824 | sdd->sgc = alloc_percpu(struct sched_group_capacity *); |
6825 | if (!sdd->sgc) | |
9c3f75cb PZ |
6826 | return -ENOMEM; |
6827 | ||
54ab4ff4 PZ |
6828 | for_each_cpu(j, cpu_map) { |
6829 | struct sched_domain *sd; | |
6830 | struct sched_group *sg; | |
63b2ca30 | 6831 | struct sched_group_capacity *sgc; |
54ab4ff4 | 6832 | |
5cc389bc | 6833 | sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), |
54ab4ff4 PZ |
6834 | GFP_KERNEL, cpu_to_node(j)); |
6835 | if (!sd) | |
6836 | return -ENOMEM; | |
6837 | ||
6838 | *per_cpu_ptr(sdd->sd, j) = sd; | |
6839 | ||
6840 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), | |
6841 | GFP_KERNEL, cpu_to_node(j)); | |
6842 | if (!sg) | |
6843 | return -ENOMEM; | |
6844 | ||
30b4e9eb IM |
6845 | sg->next = sg; |
6846 | ||
54ab4ff4 | 6847 | *per_cpu_ptr(sdd->sg, j) = sg; |
9c3f75cb | 6848 | |
63b2ca30 | 6849 | sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), |
9c3f75cb | 6850 | GFP_KERNEL, cpu_to_node(j)); |
63b2ca30 | 6851 | if (!sgc) |
9c3f75cb PZ |
6852 | return -ENOMEM; |
6853 | ||
63b2ca30 | 6854 | *per_cpu_ptr(sdd->sgc, j) = sgc; |
54ab4ff4 PZ |
6855 | } |
6856 | } | |
6857 | ||
6858 | return 0; | |
6859 | } | |
6860 | ||
6861 | static void __sdt_free(const struct cpumask *cpu_map) | |
6862 | { | |
6863 | struct sched_domain_topology_level *tl; | |
6864 | int j; | |
6865 | ||
27723a68 | 6866 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
6867 | struct sd_data *sdd = &tl->data; |
6868 | ||
6869 | for_each_cpu(j, cpu_map) { | |
fb2cf2c6 | 6870 | struct sched_domain *sd; |
6871 | ||
6872 | if (sdd->sd) { | |
6873 | sd = *per_cpu_ptr(sdd->sd, j); | |
6874 | if (sd && (sd->flags & SD_OVERLAP)) | |
6875 | free_sched_groups(sd->groups, 0); | |
6876 | kfree(*per_cpu_ptr(sdd->sd, j)); | |
6877 | } | |
6878 | ||
6879 | if (sdd->sg) | |
6880 | kfree(*per_cpu_ptr(sdd->sg, j)); | |
63b2ca30 NP |
6881 | if (sdd->sgc) |
6882 | kfree(*per_cpu_ptr(sdd->sgc, j)); | |
54ab4ff4 PZ |
6883 | } |
6884 | free_percpu(sdd->sd); | |
fb2cf2c6 | 6885 | sdd->sd = NULL; |
54ab4ff4 | 6886 | free_percpu(sdd->sg); |
fb2cf2c6 | 6887 | sdd->sg = NULL; |
63b2ca30 NP |
6888 | free_percpu(sdd->sgc); |
6889 | sdd->sgc = NULL; | |
54ab4ff4 PZ |
6890 | } |
6891 | } | |
6892 | ||
2c402dc3 | 6893 | struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, |
4a850cbe VK |
6894 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
6895 | struct sched_domain *child, int cpu) | |
2c402dc3 | 6896 | { |
3676b13e | 6897 | struct sched_domain *sd = sd_init(tl, child, cpu); |
2c402dc3 | 6898 | |
2c402dc3 | 6899 | cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); |
60495e77 PZ |
6900 | if (child) { |
6901 | sd->level = child->level + 1; | |
6902 | sched_domain_level_max = max(sched_domain_level_max, sd->level); | |
d069b916 | 6903 | child->parent = sd; |
6ae72dff PZ |
6904 | |
6905 | if (!cpumask_subset(sched_domain_span(child), | |
6906 | sched_domain_span(sd))) { | |
6907 | pr_err("BUG: arch topology borken\n"); | |
6908 | #ifdef CONFIG_SCHED_DEBUG | |
6909 | pr_err(" the %s domain not a subset of the %s domain\n", | |
6910 | child->name, sd->name); | |
6911 | #endif | |
6912 | /* Fixup, ensure @sd has at least @child cpus. */ | |
6913 | cpumask_or(sched_domain_span(sd), | |
6914 | sched_domain_span(sd), | |
6915 | sched_domain_span(child)); | |
6916 | } | |
6917 | ||
60495e77 | 6918 | } |
a841f8ce | 6919 | set_domain_attribute(sd, attr); |
2c402dc3 PZ |
6920 | |
6921 | return sd; | |
6922 | } | |
6923 | ||
2109b99e AH |
6924 | /* |
6925 | * Build sched domains for a given set of cpus and attach the sched domains | |
6926 | * to the individual cpus | |
6927 | */ | |
dce840a0 PZ |
6928 | static int build_sched_domains(const struct cpumask *cpu_map, |
6929 | struct sched_domain_attr *attr) | |
2109b99e | 6930 | { |
1c632169 | 6931 | enum s_alloc alloc_state; |
dce840a0 | 6932 | struct sched_domain *sd; |
2109b99e | 6933 | struct s_data d; |
cd92bfd3 | 6934 | struct rq *rq = NULL; |
822ff793 | 6935 | int i, ret = -ENOMEM; |
9c1cfda2 | 6936 | |
2109b99e AH |
6937 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
6938 | if (alloc_state != sa_rootdomain) | |
6939 | goto error; | |
9c1cfda2 | 6940 | |
dce840a0 | 6941 | /* Set up domains for cpus specified by the cpu_map. */ |
abcd083a | 6942 | for_each_cpu(i, cpu_map) { |
eb7a74e6 PZ |
6943 | struct sched_domain_topology_level *tl; |
6944 | ||
3bd65a80 | 6945 | sd = NULL; |
27723a68 | 6946 | for_each_sd_topology(tl) { |
4a850cbe | 6947 | sd = build_sched_domain(tl, cpu_map, attr, sd, i); |
22da9569 VK |
6948 | if (tl == sched_domain_topology) |
6949 | *per_cpu_ptr(d.sd, i) = sd; | |
e3589f6c PZ |
6950 | if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) |
6951 | sd->flags |= SD_OVERLAP; | |
d110235d PZ |
6952 | if (cpumask_equal(cpu_map, sched_domain_span(sd))) |
6953 | break; | |
e3589f6c | 6954 | } |
dce840a0 PZ |
6955 | } |
6956 | ||
6957 | /* Build the groups for the domains */ | |
6958 | for_each_cpu(i, cpu_map) { | |
6959 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { | |
6960 | sd->span_weight = cpumask_weight(sched_domain_span(sd)); | |
e3589f6c PZ |
6961 | if (sd->flags & SD_OVERLAP) { |
6962 | if (build_overlap_sched_groups(sd, i)) | |
6963 | goto error; | |
6964 | } else { | |
6965 | if (build_sched_groups(sd, i)) | |
6966 | goto error; | |
6967 | } | |
1cf51902 | 6968 | } |
a06dadbe | 6969 | } |
9c1cfda2 | 6970 | |
ced549fa | 6971 | /* Calculate CPU capacity for physical packages and nodes */ |
a9c9a9b6 PZ |
6972 | for (i = nr_cpumask_bits-1; i >= 0; i--) { |
6973 | if (!cpumask_test_cpu(i, cpu_map)) | |
6974 | continue; | |
9c1cfda2 | 6975 | |
dce840a0 PZ |
6976 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { |
6977 | claim_allocations(i, sd); | |
63b2ca30 | 6978 | init_sched_groups_capacity(i, sd); |
dce840a0 | 6979 | } |
f712c0c7 | 6980 | } |
9c1cfda2 | 6981 | |
1da177e4 | 6982 | /* Attach the domains */ |
dce840a0 | 6983 | rcu_read_lock(); |
abcd083a | 6984 | for_each_cpu(i, cpu_map) { |
cd92bfd3 | 6985 | rq = cpu_rq(i); |
21d42ccf | 6986 | sd = *per_cpu_ptr(d.sd, i); |
cd92bfd3 DE |
6987 | |
6988 | /* Use READ_ONCE()/WRITE_ONCE() to avoid load/store tearing: */ | |
6989 | if (rq->cpu_capacity_orig > READ_ONCE(d.rd->max_cpu_capacity)) | |
6990 | WRITE_ONCE(d.rd->max_cpu_capacity, rq->cpu_capacity_orig); | |
6991 | ||
49a02c51 | 6992 | cpu_attach_domain(sd, d.rd, i); |
1da177e4 | 6993 | } |
dce840a0 | 6994 | rcu_read_unlock(); |
51888ca2 | 6995 | |
cd92bfd3 DE |
6996 | if (rq) { |
6997 | pr_info("span: %*pbl (max cpu_capacity = %lu)\n", | |
6998 | cpumask_pr_args(cpu_map), rq->rd->max_cpu_capacity); | |
6999 | } | |
7000 | ||
822ff793 | 7001 | ret = 0; |
51888ca2 | 7002 | error: |
2109b99e | 7003 | __free_domain_allocs(&d, alloc_state, cpu_map); |
822ff793 | 7004 | return ret; |
1da177e4 | 7005 | } |
029190c5 | 7006 | |
acc3f5d7 | 7007 | static cpumask_var_t *doms_cur; /* current sched domains */ |
029190c5 | 7008 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
4285f594 IM |
7009 | static struct sched_domain_attr *dattr_cur; |
7010 | /* attribues of custom domains in 'doms_cur' */ | |
029190c5 PJ |
7011 | |
7012 | /* | |
7013 | * Special case: If a kmalloc of a doms_cur partition (array of | |
4212823f RR |
7014 | * cpumask) fails, then fallback to a single sched domain, |
7015 | * as determined by the single cpumask fallback_doms. | |
029190c5 | 7016 | */ |
4212823f | 7017 | static cpumask_var_t fallback_doms; |
029190c5 | 7018 | |
ee79d1bd HC |
7019 | /* |
7020 | * arch_update_cpu_topology lets virtualized architectures update the | |
7021 | * cpu core maps. It is supposed to return 1 if the topology changed | |
7022 | * or 0 if it stayed the same. | |
7023 | */ | |
52f5684c | 7024 | int __weak arch_update_cpu_topology(void) |
22e52b07 | 7025 | { |
ee79d1bd | 7026 | return 0; |
22e52b07 HC |
7027 | } |
7028 | ||
acc3f5d7 RR |
7029 | cpumask_var_t *alloc_sched_domains(unsigned int ndoms) |
7030 | { | |
7031 | int i; | |
7032 | cpumask_var_t *doms; | |
7033 | ||
7034 | doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); | |
7035 | if (!doms) | |
7036 | return NULL; | |
7037 | for (i = 0; i < ndoms; i++) { | |
7038 | if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { | |
7039 | free_sched_domains(doms, i); | |
7040 | return NULL; | |
7041 | } | |
7042 | } | |
7043 | return doms; | |
7044 | } | |
7045 | ||
7046 | void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) | |
7047 | { | |
7048 | unsigned int i; | |
7049 | for (i = 0; i < ndoms; i++) | |
7050 | free_cpumask_var(doms[i]); | |
7051 | kfree(doms); | |
7052 | } | |
7053 | ||
1a20ff27 | 7054 | /* |
41a2d6cf | 7055 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
7056 | * For now this just excludes isolated cpus, but could be used to |
7057 | * exclude other special cases in the future. | |
1a20ff27 | 7058 | */ |
c4a8849a | 7059 | static int init_sched_domains(const struct cpumask *cpu_map) |
1a20ff27 | 7060 | { |
7378547f MM |
7061 | int err; |
7062 | ||
22e52b07 | 7063 | arch_update_cpu_topology(); |
029190c5 | 7064 | ndoms_cur = 1; |
acc3f5d7 | 7065 | doms_cur = alloc_sched_domains(ndoms_cur); |
029190c5 | 7066 | if (!doms_cur) |
acc3f5d7 RR |
7067 | doms_cur = &fallback_doms; |
7068 | cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); | |
dce840a0 | 7069 | err = build_sched_domains(doms_cur[0], NULL); |
6382bc90 | 7070 | register_sched_domain_sysctl(); |
7378547f MM |
7071 | |
7072 | return err; | |
1a20ff27 DG |
7073 | } |
7074 | ||
1a20ff27 DG |
7075 | /* |
7076 | * Detach sched domains from a group of cpus specified in cpu_map | |
7077 | * These cpus will now be attached to the NULL domain | |
7078 | */ | |
96f874e2 | 7079 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
1a20ff27 DG |
7080 | { |
7081 | int i; | |
7082 | ||
dce840a0 | 7083 | rcu_read_lock(); |
abcd083a | 7084 | for_each_cpu(i, cpu_map) |
57d885fe | 7085 | cpu_attach_domain(NULL, &def_root_domain, i); |
dce840a0 | 7086 | rcu_read_unlock(); |
1a20ff27 DG |
7087 | } |
7088 | ||
1d3504fc HS |
7089 | /* handle null as "default" */ |
7090 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, | |
7091 | struct sched_domain_attr *new, int idx_new) | |
7092 | { | |
7093 | struct sched_domain_attr tmp; | |
7094 | ||
7095 | /* fast path */ | |
7096 | if (!new && !cur) | |
7097 | return 1; | |
7098 | ||
7099 | tmp = SD_ATTR_INIT; | |
7100 | return !memcmp(cur ? (cur + idx_cur) : &tmp, | |
7101 | new ? (new + idx_new) : &tmp, | |
7102 | sizeof(struct sched_domain_attr)); | |
7103 | } | |
7104 | ||
029190c5 PJ |
7105 | /* |
7106 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 7107 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
7108 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
7109 | * It destroys each deleted domain and builds each new domain. | |
7110 | * | |
acc3f5d7 | 7111 | * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. |
41a2d6cf IM |
7112 | * The masks don't intersect (don't overlap.) We should setup one |
7113 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
7114 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
7115 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
7116 | * it as it is. | |
7117 | * | |
acc3f5d7 RR |
7118 | * The passed in 'doms_new' should be allocated using |
7119 | * alloc_sched_domains. This routine takes ownership of it and will | |
7120 | * free_sched_domains it when done with it. If the caller failed the | |
7121 | * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, | |
7122 | * and partition_sched_domains() will fallback to the single partition | |
7123 | * 'fallback_doms', it also forces the domains to be rebuilt. | |
029190c5 | 7124 | * |
96f874e2 | 7125 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
700018e0 LZ |
7126 | * ndoms_new == 0 is a special case for destroying existing domains, |
7127 | * and it will not create the default domain. | |
dfb512ec | 7128 | * |
029190c5 PJ |
7129 | * Call with hotplug lock held |
7130 | */ | |
acc3f5d7 | 7131 | void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
1d3504fc | 7132 | struct sched_domain_attr *dattr_new) |
029190c5 | 7133 | { |
dfb512ec | 7134 | int i, j, n; |
d65bd5ec | 7135 | int new_topology; |
029190c5 | 7136 | |
712555ee | 7137 | mutex_lock(&sched_domains_mutex); |
a1835615 | 7138 | |
7378547f MM |
7139 | /* always unregister in case we don't destroy any domains */ |
7140 | unregister_sched_domain_sysctl(); | |
7141 | ||
d65bd5ec HC |
7142 | /* Let architecture update cpu core mappings. */ |
7143 | new_topology = arch_update_cpu_topology(); | |
7144 | ||
dfb512ec | 7145 | n = doms_new ? ndoms_new : 0; |
029190c5 PJ |
7146 | |
7147 | /* Destroy deleted domains */ | |
7148 | for (i = 0; i < ndoms_cur; i++) { | |
d65bd5ec | 7149 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 7150 | if (cpumask_equal(doms_cur[i], doms_new[j]) |
1d3504fc | 7151 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
029190c5 PJ |
7152 | goto match1; |
7153 | } | |
7154 | /* no match - a current sched domain not in new doms_new[] */ | |
acc3f5d7 | 7155 | detach_destroy_domains(doms_cur[i]); |
029190c5 PJ |
7156 | match1: |
7157 | ; | |
7158 | } | |
7159 | ||
c8d2d47a | 7160 | n = ndoms_cur; |
e761b772 | 7161 | if (doms_new == NULL) { |
c8d2d47a | 7162 | n = 0; |
acc3f5d7 | 7163 | doms_new = &fallback_doms; |
6ad4c188 | 7164 | cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); |
faa2f98f | 7165 | WARN_ON_ONCE(dattr_new); |
e761b772 MK |
7166 | } |
7167 | ||
029190c5 PJ |
7168 | /* Build new domains */ |
7169 | for (i = 0; i < ndoms_new; i++) { | |
c8d2d47a | 7170 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 7171 | if (cpumask_equal(doms_new[i], doms_cur[j]) |
1d3504fc | 7172 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
029190c5 PJ |
7173 | goto match2; |
7174 | } | |
7175 | /* no match - add a new doms_new */ | |
dce840a0 | 7176 | build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); |
029190c5 PJ |
7177 | match2: |
7178 | ; | |
7179 | } | |
7180 | ||
7181 | /* Remember the new sched domains */ | |
acc3f5d7 RR |
7182 | if (doms_cur != &fallback_doms) |
7183 | free_sched_domains(doms_cur, ndoms_cur); | |
1d3504fc | 7184 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
029190c5 | 7185 | doms_cur = doms_new; |
1d3504fc | 7186 | dattr_cur = dattr_new; |
029190c5 | 7187 | ndoms_cur = ndoms_new; |
7378547f MM |
7188 | |
7189 | register_sched_domain_sysctl(); | |
a1835615 | 7190 | |
712555ee | 7191 | mutex_unlock(&sched_domains_mutex); |
029190c5 PJ |
7192 | } |
7193 | ||
d35be8ba SB |
7194 | static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ |
7195 | ||
1da177e4 | 7196 | /* |
3a101d05 TH |
7197 | * Update cpusets according to cpu_active mask. If cpusets are |
7198 | * disabled, cpuset_update_active_cpus() becomes a simple wrapper | |
7199 | * around partition_sched_domains(). | |
d35be8ba SB |
7200 | * |
7201 | * If we come here as part of a suspend/resume, don't touch cpusets because we | |
7202 | * want to restore it back to its original state upon resume anyway. | |
1da177e4 | 7203 | */ |
40190a78 | 7204 | static void cpuset_cpu_active(void) |
e761b772 | 7205 | { |
40190a78 | 7206 | if (cpuhp_tasks_frozen) { |
d35be8ba SB |
7207 | /* |
7208 | * num_cpus_frozen tracks how many CPUs are involved in suspend | |
7209 | * resume sequence. As long as this is not the last online | |
7210 | * operation in the resume sequence, just build a single sched | |
7211 | * domain, ignoring cpusets. | |
7212 | */ | |
7213 | num_cpus_frozen--; | |
7214 | if (likely(num_cpus_frozen)) { | |
7215 | partition_sched_domains(1, NULL, NULL); | |
135fb3e1 | 7216 | return; |
d35be8ba | 7217 | } |
d35be8ba SB |
7218 | /* |
7219 | * This is the last CPU online operation. So fall through and | |
7220 | * restore the original sched domains by considering the | |
7221 | * cpuset configurations. | |
7222 | */ | |
3a101d05 | 7223 | } |
135fb3e1 | 7224 | cpuset_update_active_cpus(true); |
3a101d05 | 7225 | } |
e761b772 | 7226 | |
40190a78 | 7227 | static int cpuset_cpu_inactive(unsigned int cpu) |
3a101d05 | 7228 | { |
3c18d447 | 7229 | unsigned long flags; |
3c18d447 | 7230 | struct dl_bw *dl_b; |
533445c6 OS |
7231 | bool overflow; |
7232 | int cpus; | |
3c18d447 | 7233 | |
40190a78 | 7234 | if (!cpuhp_tasks_frozen) { |
533445c6 OS |
7235 | rcu_read_lock_sched(); |
7236 | dl_b = dl_bw_of(cpu); | |
3c18d447 | 7237 | |
533445c6 OS |
7238 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
7239 | cpus = dl_bw_cpus(cpu); | |
7240 | overflow = __dl_overflow(dl_b, cpus, 0, 0); | |
7241 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
3c18d447 | 7242 | |
533445c6 | 7243 | rcu_read_unlock_sched(); |
3c18d447 | 7244 | |
533445c6 | 7245 | if (overflow) |
135fb3e1 | 7246 | return -EBUSY; |
7ddf96b0 | 7247 | cpuset_update_active_cpus(false); |
135fb3e1 | 7248 | } else { |
d35be8ba SB |
7249 | num_cpus_frozen++; |
7250 | partition_sched_domains(1, NULL, NULL); | |
e761b772 | 7251 | } |
135fb3e1 | 7252 | return 0; |
e761b772 | 7253 | } |
e761b772 | 7254 | |
40190a78 | 7255 | int sched_cpu_activate(unsigned int cpu) |
135fb3e1 | 7256 | { |
7d976699 TG |
7257 | struct rq *rq = cpu_rq(cpu); |
7258 | unsigned long flags; | |
7259 | ||
40190a78 | 7260 | set_cpu_active(cpu, true); |
135fb3e1 | 7261 | |
40190a78 | 7262 | if (sched_smp_initialized) { |
135fb3e1 | 7263 | sched_domains_numa_masks_set(cpu); |
40190a78 | 7264 | cpuset_cpu_active(); |
e761b772 | 7265 | } |
7d976699 TG |
7266 | |
7267 | /* | |
7268 | * Put the rq online, if not already. This happens: | |
7269 | * | |
7270 | * 1) In the early boot process, because we build the real domains | |
7271 | * after all cpus have been brought up. | |
7272 | * | |
7273 | * 2) At runtime, if cpuset_cpu_active() fails to rebuild the | |
7274 | * domains. | |
7275 | */ | |
7276 | raw_spin_lock_irqsave(&rq->lock, flags); | |
7277 | if (rq->rd) { | |
7278 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); | |
7279 | set_rq_online(rq); | |
7280 | } | |
7281 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
7282 | ||
7283 | update_max_interval(); | |
7284 | ||
40190a78 | 7285 | return 0; |
135fb3e1 TG |
7286 | } |
7287 | ||
40190a78 | 7288 | int sched_cpu_deactivate(unsigned int cpu) |
135fb3e1 | 7289 | { |
135fb3e1 TG |
7290 | int ret; |
7291 | ||
40190a78 | 7292 | set_cpu_active(cpu, false); |
b2454caa PZ |
7293 | /* |
7294 | * We've cleared cpu_active_mask, wait for all preempt-disabled and RCU | |
7295 | * users of this state to go away such that all new such users will | |
7296 | * observe it. | |
7297 | * | |
7298 | * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might | |
7299 | * not imply sync_sched(), so wait for both. | |
7300 | * | |
7301 | * Do sync before park smpboot threads to take care the rcu boost case. | |
7302 | */ | |
7303 | if (IS_ENABLED(CONFIG_PREEMPT)) | |
7304 | synchronize_rcu_mult(call_rcu, call_rcu_sched); | |
7305 | else | |
7306 | synchronize_rcu(); | |
40190a78 TG |
7307 | |
7308 | if (!sched_smp_initialized) | |
7309 | return 0; | |
7310 | ||
7311 | ret = cpuset_cpu_inactive(cpu); | |
7312 | if (ret) { | |
7313 | set_cpu_active(cpu, true); | |
7314 | return ret; | |
135fb3e1 | 7315 | } |
40190a78 TG |
7316 | sched_domains_numa_masks_clear(cpu); |
7317 | return 0; | |
135fb3e1 TG |
7318 | } |
7319 | ||
94baf7a5 TG |
7320 | static void sched_rq_cpu_starting(unsigned int cpu) |
7321 | { | |
7322 | struct rq *rq = cpu_rq(cpu); | |
7323 | ||
7324 | rq->calc_load_update = calc_load_update; | |
94baf7a5 TG |
7325 | update_max_interval(); |
7326 | } | |
7327 | ||
135fb3e1 TG |
7328 | int sched_cpu_starting(unsigned int cpu) |
7329 | { | |
7330 | set_cpu_rq_start_time(cpu); | |
94baf7a5 | 7331 | sched_rq_cpu_starting(cpu); |
135fb3e1 | 7332 | return 0; |
e761b772 | 7333 | } |
e761b772 | 7334 | |
f2785ddb TG |
7335 | #ifdef CONFIG_HOTPLUG_CPU |
7336 | int sched_cpu_dying(unsigned int cpu) | |
7337 | { | |
7338 | struct rq *rq = cpu_rq(cpu); | |
7339 | unsigned long flags; | |
7340 | ||
7341 | /* Handle pending wakeups and then migrate everything off */ | |
7342 | sched_ttwu_pending(); | |
7343 | raw_spin_lock_irqsave(&rq->lock, flags); | |
7344 | if (rq->rd) { | |
7345 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); | |
7346 | set_rq_offline(rq); | |
7347 | } | |
7348 | migrate_tasks(rq); | |
7349 | BUG_ON(rq->nr_running != 1); | |
7350 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
7351 | calc_load_migrate(rq); | |
7352 | update_max_interval(); | |
20a5c8cc | 7353 | nohz_balance_exit_idle(cpu); |
e5ef27d0 | 7354 | hrtick_clear(rq); |
f2785ddb TG |
7355 | return 0; |
7356 | } | |
7357 | #endif | |
7358 | ||
1da177e4 LT |
7359 | void __init sched_init_smp(void) |
7360 | { | |
dcc30a35 RR |
7361 | cpumask_var_t non_isolated_cpus; |
7362 | ||
7363 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); | |
cb5fd13f | 7364 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
5c1e1767 | 7365 | |
cb83b629 PZ |
7366 | sched_init_numa(); |
7367 | ||
6acce3ef PZ |
7368 | /* |
7369 | * There's no userspace yet to cause hotplug operations; hence all the | |
7370 | * cpu masks are stable and all blatant races in the below code cannot | |
7371 | * happen. | |
7372 | */ | |
712555ee | 7373 | mutex_lock(&sched_domains_mutex); |
c4a8849a | 7374 | init_sched_domains(cpu_active_mask); |
dcc30a35 RR |
7375 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
7376 | if (cpumask_empty(non_isolated_cpus)) | |
7377 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); | |
712555ee | 7378 | mutex_unlock(&sched_domains_mutex); |
e761b772 | 7379 | |
5c1e1767 | 7380 | /* Move init over to a non-isolated CPU */ |
dcc30a35 | 7381 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
5c1e1767 | 7382 | BUG(); |
19978ca6 | 7383 | sched_init_granularity(); |
dcc30a35 | 7384 | free_cpumask_var(non_isolated_cpus); |
4212823f | 7385 | |
0e3900e6 | 7386 | init_sched_rt_class(); |
1baca4ce | 7387 | init_sched_dl_class(); |
e26fbffd | 7388 | sched_smp_initialized = true; |
1da177e4 | 7389 | } |
e26fbffd TG |
7390 | |
7391 | static int __init migration_init(void) | |
7392 | { | |
94baf7a5 | 7393 | sched_rq_cpu_starting(smp_processor_id()); |
e26fbffd | 7394 | return 0; |
1da177e4 | 7395 | } |
e26fbffd TG |
7396 | early_initcall(migration_init); |
7397 | ||
1da177e4 LT |
7398 | #else |
7399 | void __init sched_init_smp(void) | |
7400 | { | |
19978ca6 | 7401 | sched_init_granularity(); |
1da177e4 LT |
7402 | } |
7403 | #endif /* CONFIG_SMP */ | |
7404 | ||
7405 | int in_sched_functions(unsigned long addr) | |
7406 | { | |
1da177e4 LT |
7407 | return in_lock_functions(addr) || |
7408 | (addr >= (unsigned long)__sched_text_start | |
7409 | && addr < (unsigned long)__sched_text_end); | |
7410 | } | |
7411 | ||
029632fb | 7412 | #ifdef CONFIG_CGROUP_SCHED |
27b4b931 LZ |
7413 | /* |
7414 | * Default task group. | |
7415 | * Every task in system belongs to this group at bootup. | |
7416 | */ | |
029632fb | 7417 | struct task_group root_task_group; |
35cf4e50 | 7418 | LIST_HEAD(task_groups); |
b0367629 WL |
7419 | |
7420 | /* Cacheline aligned slab cache for task_group */ | |
7421 | static struct kmem_cache *task_group_cache __read_mostly; | |
052f1dc7 | 7422 | #endif |
6f505b16 | 7423 | |
e6252c3e | 7424 | DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); |
6f505b16 | 7425 | |
1da177e4 LT |
7426 | void __init sched_init(void) |
7427 | { | |
dd41f596 | 7428 | int i, j; |
434d53b0 MT |
7429 | unsigned long alloc_size = 0, ptr; |
7430 | ||
7431 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
7432 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
7433 | #endif | |
7434 | #ifdef CONFIG_RT_GROUP_SCHED | |
7435 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
7436 | #endif | |
434d53b0 | 7437 | if (alloc_size) { |
36b7b6d4 | 7438 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
434d53b0 MT |
7439 | |
7440 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
07e06b01 | 7441 | root_task_group.se = (struct sched_entity **)ptr; |
434d53b0 MT |
7442 | ptr += nr_cpu_ids * sizeof(void **); |
7443 | ||
07e06b01 | 7444 | root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
434d53b0 | 7445 | ptr += nr_cpu_ids * sizeof(void **); |
eff766a6 | 7446 | |
6d6bc0ad | 7447 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
434d53b0 | 7448 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7449 | root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
434d53b0 MT |
7450 | ptr += nr_cpu_ids * sizeof(void **); |
7451 | ||
07e06b01 | 7452 | root_task_group.rt_rq = (struct rt_rq **)ptr; |
eff766a6 PZ |
7453 | ptr += nr_cpu_ids * sizeof(void **); |
7454 | ||
6d6bc0ad | 7455 | #endif /* CONFIG_RT_GROUP_SCHED */ |
b74e6278 | 7456 | } |
df7c8e84 | 7457 | #ifdef CONFIG_CPUMASK_OFFSTACK |
b74e6278 AT |
7458 | for_each_possible_cpu(i) { |
7459 | per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node( | |
7460 | cpumask_size(), GFP_KERNEL, cpu_to_node(i)); | |
434d53b0 | 7461 | } |
b74e6278 | 7462 | #endif /* CONFIG_CPUMASK_OFFSTACK */ |
dd41f596 | 7463 | |
332ac17e DF |
7464 | init_rt_bandwidth(&def_rt_bandwidth, |
7465 | global_rt_period(), global_rt_runtime()); | |
7466 | init_dl_bandwidth(&def_dl_bandwidth, | |
1724813d | 7467 | global_rt_period(), global_rt_runtime()); |
332ac17e | 7468 | |
57d885fe GH |
7469 | #ifdef CONFIG_SMP |
7470 | init_defrootdomain(); | |
7471 | #endif | |
7472 | ||
d0b27fa7 | 7473 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7474 | init_rt_bandwidth(&root_task_group.rt_bandwidth, |
d0b27fa7 | 7475 | global_rt_period(), global_rt_runtime()); |
6d6bc0ad | 7476 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 7477 | |
7c941438 | 7478 | #ifdef CONFIG_CGROUP_SCHED |
b0367629 WL |
7479 | task_group_cache = KMEM_CACHE(task_group, 0); |
7480 | ||
07e06b01 YZ |
7481 | list_add(&root_task_group.list, &task_groups); |
7482 | INIT_LIST_HEAD(&root_task_group.children); | |
f4d6f6c2 | 7483 | INIT_LIST_HEAD(&root_task_group.siblings); |
5091faa4 | 7484 | autogroup_init(&init_task); |
7c941438 | 7485 | #endif /* CONFIG_CGROUP_SCHED */ |
6f505b16 | 7486 | |
0a945022 | 7487 | for_each_possible_cpu(i) { |
70b97a7f | 7488 | struct rq *rq; |
1da177e4 LT |
7489 | |
7490 | rq = cpu_rq(i); | |
05fa785c | 7491 | raw_spin_lock_init(&rq->lock); |
7897986b | 7492 | rq->nr_running = 0; |
dce48a84 TG |
7493 | rq->calc_load_active = 0; |
7494 | rq->calc_load_update = jiffies + LOAD_FREQ; | |
acb5a9ba | 7495 | init_cfs_rq(&rq->cfs); |
07c54f7a AV |
7496 | init_rt_rq(&rq->rt); |
7497 | init_dl_rq(&rq->dl); | |
dd41f596 | 7498 | #ifdef CONFIG_FAIR_GROUP_SCHED |
029632fb | 7499 | root_task_group.shares = ROOT_TASK_GROUP_LOAD; |
6f505b16 | 7500 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
354d60c2 | 7501 | /* |
07e06b01 | 7502 | * How much cpu bandwidth does root_task_group get? |
354d60c2 DG |
7503 | * |
7504 | * In case of task-groups formed thr' the cgroup filesystem, it | |
7505 | * gets 100% of the cpu resources in the system. This overall | |
7506 | * system cpu resource is divided among the tasks of | |
07e06b01 | 7507 | * root_task_group and its child task-groups in a fair manner, |
354d60c2 DG |
7508 | * based on each entity's (task or task-group's) weight |
7509 | * (se->load.weight). | |
7510 | * | |
07e06b01 | 7511 | * In other words, if root_task_group has 10 tasks of weight |
354d60c2 DG |
7512 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
7513 | * then A0's share of the cpu resource is: | |
7514 | * | |
0d905bca | 7515 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
354d60c2 | 7516 | * |
07e06b01 YZ |
7517 | * We achieve this by letting root_task_group's tasks sit |
7518 | * directly in rq->cfs (i.e root_task_group->se[] = NULL). | |
354d60c2 | 7519 | */ |
ab84d31e | 7520 | init_cfs_bandwidth(&root_task_group.cfs_bandwidth); |
07e06b01 | 7521 | init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); |
354d60c2 DG |
7522 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7523 | ||
7524 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; | |
052f1dc7 | 7525 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7526 | init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); |
dd41f596 | 7527 | #endif |
1da177e4 | 7528 | |
dd41f596 IM |
7529 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
7530 | rq->cpu_load[j] = 0; | |
fdf3e95d | 7531 | |
1da177e4 | 7532 | #ifdef CONFIG_SMP |
41c7ce9a | 7533 | rq->sd = NULL; |
57d885fe | 7534 | rq->rd = NULL; |
ca6d75e6 | 7535 | rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE; |
e3fca9e7 | 7536 | rq->balance_callback = NULL; |
1da177e4 | 7537 | rq->active_balance = 0; |
dd41f596 | 7538 | rq->next_balance = jiffies; |
1da177e4 | 7539 | rq->push_cpu = 0; |
0a2966b4 | 7540 | rq->cpu = i; |
1f11eb6a | 7541 | rq->online = 0; |
eae0c9df MG |
7542 | rq->idle_stamp = 0; |
7543 | rq->avg_idle = 2*sysctl_sched_migration_cost; | |
9bd721c5 | 7544 | rq->max_idle_balance_cost = sysctl_sched_migration_cost; |
367456c7 PZ |
7545 | |
7546 | INIT_LIST_HEAD(&rq->cfs_tasks); | |
7547 | ||
dc938520 | 7548 | rq_attach_root(rq, &def_root_domain); |
3451d024 | 7549 | #ifdef CONFIG_NO_HZ_COMMON |
9fd81dd5 | 7550 | rq->last_load_update_tick = jiffies; |
1c792db7 | 7551 | rq->nohz_flags = 0; |
83cd4fe2 | 7552 | #endif |
265f22a9 FW |
7553 | #ifdef CONFIG_NO_HZ_FULL |
7554 | rq->last_sched_tick = 0; | |
7555 | #endif | |
9fd81dd5 | 7556 | #endif /* CONFIG_SMP */ |
8f4d37ec | 7557 | init_rq_hrtick(rq); |
1da177e4 | 7558 | atomic_set(&rq->nr_iowait, 0); |
1da177e4 LT |
7559 | } |
7560 | ||
2dd73a4f | 7561 | set_load_weight(&init_task); |
b50f60ce | 7562 | |
1da177e4 LT |
7563 | /* |
7564 | * The boot idle thread does lazy MMU switching as well: | |
7565 | */ | |
7566 | atomic_inc(&init_mm.mm_count); | |
7567 | enter_lazy_tlb(&init_mm, current); | |
7568 | ||
1b537c7d YD |
7569 | /* |
7570 | * During early bootup we pretend to be a normal task: | |
7571 | */ | |
7572 | current->sched_class = &fair_sched_class; | |
7573 | ||
1da177e4 LT |
7574 | /* |
7575 | * Make us the idle thread. Technically, schedule() should not be | |
7576 | * called from this thread, however somewhere below it might be, | |
7577 | * but because we are the idle thread, we just pick up running again | |
7578 | * when this runqueue becomes "idle". | |
7579 | */ | |
7580 | init_idle(current, smp_processor_id()); | |
dce48a84 TG |
7581 | |
7582 | calc_load_update = jiffies + LOAD_FREQ; | |
7583 | ||
bf4d83f6 | 7584 | #ifdef CONFIG_SMP |
4cb98839 | 7585 | zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); |
bdddd296 RR |
7586 | /* May be allocated at isolcpus cmdline parse time */ |
7587 | if (cpu_isolated_map == NULL) | |
7588 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); | |
29d5e047 | 7589 | idle_thread_set_boot_cpu(); |
9cf7243d | 7590 | set_cpu_rq_start_time(smp_processor_id()); |
029632fb PZ |
7591 | #endif |
7592 | init_sched_fair_class(); | |
6a7b3dc3 | 7593 | |
4698f88c JP |
7594 | init_schedstats(); |
7595 | ||
6892b75e | 7596 | scheduler_running = 1; |
1da177e4 LT |
7597 | } |
7598 | ||
d902db1e | 7599 | #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
e4aafea2 FW |
7600 | static inline int preempt_count_equals(int preempt_offset) |
7601 | { | |
da7142e2 | 7602 | int nested = preempt_count() + rcu_preempt_depth(); |
e4aafea2 | 7603 | |
4ba8216c | 7604 | return (nested == preempt_offset); |
e4aafea2 FW |
7605 | } |
7606 | ||
d894837f | 7607 | void __might_sleep(const char *file, int line, int preempt_offset) |
1da177e4 | 7608 | { |
8eb23b9f PZ |
7609 | /* |
7610 | * Blocking primitives will set (and therefore destroy) current->state, | |
7611 | * since we will exit with TASK_RUNNING make sure we enter with it, | |
7612 | * otherwise we will destroy state. | |
7613 | */ | |
00845eb9 | 7614 | WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, |
8eb23b9f PZ |
7615 | "do not call blocking ops when !TASK_RUNNING; " |
7616 | "state=%lx set at [<%p>] %pS\n", | |
7617 | current->state, | |
7618 | (void *)current->task_state_change, | |
00845eb9 | 7619 | (void *)current->task_state_change); |
8eb23b9f | 7620 | |
3427445a PZ |
7621 | ___might_sleep(file, line, preempt_offset); |
7622 | } | |
7623 | EXPORT_SYMBOL(__might_sleep); | |
7624 | ||
7625 | void ___might_sleep(const char *file, int line, int preempt_offset) | |
1da177e4 | 7626 | { |
1da177e4 | 7627 | static unsigned long prev_jiffy; /* ratelimiting */ |
d1c6d149 | 7628 | unsigned long preempt_disable_ip; |
1da177e4 | 7629 | |
b3fbab05 | 7630 | rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ |
db273be2 TG |
7631 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && |
7632 | !is_idle_task(current)) || | |
e4aafea2 | 7633 | system_state != SYSTEM_RUNNING || oops_in_progress) |
aef745fc IM |
7634 | return; |
7635 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
7636 | return; | |
7637 | prev_jiffy = jiffies; | |
7638 | ||
d1c6d149 VN |
7639 | /* Save this before calling printk(), since that will clobber it */ |
7640 | preempt_disable_ip = get_preempt_disable_ip(current); | |
7641 | ||
3df0fc5b PZ |
7642 | printk(KERN_ERR |
7643 | "BUG: sleeping function called from invalid context at %s:%d\n", | |
7644 | file, line); | |
7645 | printk(KERN_ERR | |
7646 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", | |
7647 | in_atomic(), irqs_disabled(), | |
7648 | current->pid, current->comm); | |
aef745fc | 7649 | |
a8b686b3 ES |
7650 | if (task_stack_end_corrupted(current)) |
7651 | printk(KERN_EMERG "Thread overran stack, or stack corrupted\n"); | |
7652 | ||
aef745fc IM |
7653 | debug_show_held_locks(current); |
7654 | if (irqs_disabled()) | |
7655 | print_irqtrace_events(current); | |
d1c6d149 VN |
7656 | if (IS_ENABLED(CONFIG_DEBUG_PREEMPT) |
7657 | && !preempt_count_equals(preempt_offset)) { | |
8f47b187 | 7658 | pr_err("Preemption disabled at:"); |
d1c6d149 | 7659 | print_ip_sym(preempt_disable_ip); |
8f47b187 TG |
7660 | pr_cont("\n"); |
7661 | } | |
aef745fc | 7662 | dump_stack(); |
f0b22e39 | 7663 | add_taint(TAINT_WARN, LOCKDEP_STILL_OK); |
1da177e4 | 7664 | } |
3427445a | 7665 | EXPORT_SYMBOL(___might_sleep); |
1da177e4 LT |
7666 | #endif |
7667 | ||
7668 | #ifdef CONFIG_MAGIC_SYSRQ | |
dbc7f069 | 7669 | void normalize_rt_tasks(void) |
3a5e4dc1 | 7670 | { |
dbc7f069 | 7671 | struct task_struct *g, *p; |
d50dde5a DF |
7672 | struct sched_attr attr = { |
7673 | .sched_policy = SCHED_NORMAL, | |
7674 | }; | |
1da177e4 | 7675 | |
3472eaa1 | 7676 | read_lock(&tasklist_lock); |
5d07f420 | 7677 | for_each_process_thread(g, p) { |
178be793 IM |
7678 | /* |
7679 | * Only normalize user tasks: | |
7680 | */ | |
3472eaa1 | 7681 | if (p->flags & PF_KTHREAD) |
178be793 IM |
7682 | continue; |
7683 | ||
4fa8d299 JP |
7684 | p->se.exec_start = 0; |
7685 | schedstat_set(p->se.statistics.wait_start, 0); | |
7686 | schedstat_set(p->se.statistics.sleep_start, 0); | |
7687 | schedstat_set(p->se.statistics.block_start, 0); | |
dd41f596 | 7688 | |
aab03e05 | 7689 | if (!dl_task(p) && !rt_task(p)) { |
dd41f596 IM |
7690 | /* |
7691 | * Renice negative nice level userspace | |
7692 | * tasks back to 0: | |
7693 | */ | |
3472eaa1 | 7694 | if (task_nice(p) < 0) |
dd41f596 | 7695 | set_user_nice(p, 0); |
1da177e4 | 7696 | continue; |
dd41f596 | 7697 | } |
1da177e4 | 7698 | |
dbc7f069 | 7699 | __sched_setscheduler(p, &attr, false, false); |
5d07f420 | 7700 | } |
3472eaa1 | 7701 | read_unlock(&tasklist_lock); |
1da177e4 LT |
7702 | } |
7703 | ||
7704 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a | 7705 | |
67fc4e0c | 7706 | #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) |
1df5c10a | 7707 | /* |
67fc4e0c | 7708 | * These functions are only useful for the IA64 MCA handling, or kdb. |
1df5c10a LT |
7709 | * |
7710 | * They can only be called when the whole system has been | |
7711 | * stopped - every CPU needs to be quiescent, and no scheduling | |
7712 | * activity can take place. Using them for anything else would | |
7713 | * be a serious bug, and as a result, they aren't even visible | |
7714 | * under any other configuration. | |
7715 | */ | |
7716 | ||
7717 | /** | |
7718 | * curr_task - return the current task for a given cpu. | |
7719 | * @cpu: the processor in question. | |
7720 | * | |
7721 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
e69f6186 YB |
7722 | * |
7723 | * Return: The current task for @cpu. | |
1df5c10a | 7724 | */ |
36c8b586 | 7725 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
7726 | { |
7727 | return cpu_curr(cpu); | |
7728 | } | |
7729 | ||
67fc4e0c JW |
7730 | #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ |
7731 | ||
7732 | #ifdef CONFIG_IA64 | |
1df5c10a LT |
7733 | /** |
7734 | * set_curr_task - set the current task for a given cpu. | |
7735 | * @cpu: the processor in question. | |
7736 | * @p: the task pointer to set. | |
7737 | * | |
7738 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
7739 | * are serviced on a separate stack. It allows the architecture to switch the |
7740 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
7741 | * must be called with all CPU's synchronized, and interrupts disabled, the |
7742 | * and caller must save the original value of the current task (see | |
7743 | * curr_task() above) and restore that value before reenabling interrupts and | |
7744 | * re-starting the system. | |
7745 | * | |
7746 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
7747 | */ | |
36c8b586 | 7748 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
7749 | { |
7750 | cpu_curr(cpu) = p; | |
7751 | } | |
7752 | ||
7753 | #endif | |
29f59db3 | 7754 | |
7c941438 | 7755 | #ifdef CONFIG_CGROUP_SCHED |
029632fb PZ |
7756 | /* task_group_lock serializes the addition/removal of task groups */ |
7757 | static DEFINE_SPINLOCK(task_group_lock); | |
7758 | ||
2f5177f0 | 7759 | static void sched_free_group(struct task_group *tg) |
bccbe08a PZ |
7760 | { |
7761 | free_fair_sched_group(tg); | |
7762 | free_rt_sched_group(tg); | |
e9aa1dd1 | 7763 | autogroup_free(tg); |
b0367629 | 7764 | kmem_cache_free(task_group_cache, tg); |
bccbe08a PZ |
7765 | } |
7766 | ||
7767 | /* allocate runqueue etc for a new task group */ | |
ec7dc8ac | 7768 | struct task_group *sched_create_group(struct task_group *parent) |
bccbe08a PZ |
7769 | { |
7770 | struct task_group *tg; | |
bccbe08a | 7771 | |
b0367629 | 7772 | tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO); |
bccbe08a PZ |
7773 | if (!tg) |
7774 | return ERR_PTR(-ENOMEM); | |
7775 | ||
ec7dc8ac | 7776 | if (!alloc_fair_sched_group(tg, parent)) |
bccbe08a PZ |
7777 | goto err; |
7778 | ||
ec7dc8ac | 7779 | if (!alloc_rt_sched_group(tg, parent)) |
bccbe08a PZ |
7780 | goto err; |
7781 | ||
ace783b9 LZ |
7782 | return tg; |
7783 | ||
7784 | err: | |
2f5177f0 | 7785 | sched_free_group(tg); |
ace783b9 LZ |
7786 | return ERR_PTR(-ENOMEM); |
7787 | } | |
7788 | ||
7789 | void sched_online_group(struct task_group *tg, struct task_group *parent) | |
7790 | { | |
7791 | unsigned long flags; | |
7792 | ||
8ed36996 | 7793 | spin_lock_irqsave(&task_group_lock, flags); |
6f505b16 | 7794 | list_add_rcu(&tg->list, &task_groups); |
f473aa5e PZ |
7795 | |
7796 | WARN_ON(!parent); /* root should already exist */ | |
7797 | ||
7798 | tg->parent = parent; | |
f473aa5e | 7799 | INIT_LIST_HEAD(&tg->children); |
09f2724a | 7800 | list_add_rcu(&tg->siblings, &parent->children); |
8ed36996 | 7801 | spin_unlock_irqrestore(&task_group_lock, flags); |
8663e24d PZ |
7802 | |
7803 | online_fair_sched_group(tg); | |
29f59db3 SV |
7804 | } |
7805 | ||
9b5b7751 | 7806 | /* rcu callback to free various structures associated with a task group */ |
2f5177f0 | 7807 | static void sched_free_group_rcu(struct rcu_head *rhp) |
29f59db3 | 7808 | { |
29f59db3 | 7809 | /* now it should be safe to free those cfs_rqs */ |
2f5177f0 | 7810 | sched_free_group(container_of(rhp, struct task_group, rcu)); |
29f59db3 SV |
7811 | } |
7812 | ||
4cf86d77 | 7813 | void sched_destroy_group(struct task_group *tg) |
ace783b9 LZ |
7814 | { |
7815 | /* wait for possible concurrent references to cfs_rqs complete */ | |
2f5177f0 | 7816 | call_rcu(&tg->rcu, sched_free_group_rcu); |
ace783b9 LZ |
7817 | } |
7818 | ||
7819 | void sched_offline_group(struct task_group *tg) | |
29f59db3 | 7820 | { |
8ed36996 | 7821 | unsigned long flags; |
29f59db3 | 7822 | |
3d4b47b4 | 7823 | /* end participation in shares distribution */ |
6fe1f348 | 7824 | unregister_fair_sched_group(tg); |
3d4b47b4 PZ |
7825 | |
7826 | spin_lock_irqsave(&task_group_lock, flags); | |
6f505b16 | 7827 | list_del_rcu(&tg->list); |
f473aa5e | 7828 | list_del_rcu(&tg->siblings); |
8ed36996 | 7829 | spin_unlock_irqrestore(&task_group_lock, flags); |
29f59db3 SV |
7830 | } |
7831 | ||
ea86cb4b | 7832 | static void sched_change_group(struct task_struct *tsk, int type) |
29f59db3 | 7833 | { |
8323f26c | 7834 | struct task_group *tg; |
29f59db3 | 7835 | |
f7b8a47d KT |
7836 | /* |
7837 | * All callers are synchronized by task_rq_lock(); we do not use RCU | |
7838 | * which is pointless here. Thus, we pass "true" to task_css_check() | |
7839 | * to prevent lockdep warnings. | |
7840 | */ | |
7841 | tg = container_of(task_css_check(tsk, cpu_cgrp_id, true), | |
8323f26c PZ |
7842 | struct task_group, css); |
7843 | tg = autogroup_task_group(tsk, tg); | |
7844 | tsk->sched_task_group = tg; | |
7845 | ||
810b3817 | 7846 | #ifdef CONFIG_FAIR_GROUP_SCHED |
ea86cb4b VG |
7847 | if (tsk->sched_class->task_change_group) |
7848 | tsk->sched_class->task_change_group(tsk, type); | |
b2b5ce02 | 7849 | else |
810b3817 | 7850 | #endif |
b2b5ce02 | 7851 | set_task_rq(tsk, task_cpu(tsk)); |
ea86cb4b VG |
7852 | } |
7853 | ||
7854 | /* | |
7855 | * Change task's runqueue when it moves between groups. | |
7856 | * | |
7857 | * The caller of this function should have put the task in its new group by | |
7858 | * now. This function just updates tsk->se.cfs_rq and tsk->se.parent to reflect | |
7859 | * its new group. | |
7860 | */ | |
7861 | void sched_move_task(struct task_struct *tsk) | |
7862 | { | |
7863 | int queued, running; | |
7864 | struct rq_flags rf; | |
7865 | struct rq *rq; | |
7866 | ||
7867 | rq = task_rq_lock(tsk, &rf); | |
7868 | ||
7869 | running = task_current(rq, tsk); | |
7870 | queued = task_on_rq_queued(tsk); | |
7871 | ||
7872 | if (queued) | |
7873 | dequeue_task(rq, tsk, DEQUEUE_SAVE | DEQUEUE_MOVE); | |
7874 | if (unlikely(running)) | |
7875 | put_prev_task(rq, tsk); | |
7876 | ||
7877 | sched_change_group(tsk, TASK_MOVE_GROUP); | |
810b3817 | 7878 | |
0e1f3483 HS |
7879 | if (unlikely(running)) |
7880 | tsk->sched_class->set_curr_task(rq); | |
da0c1e65 | 7881 | if (queued) |
ff77e468 | 7882 | enqueue_task(rq, tsk, ENQUEUE_RESTORE | ENQUEUE_MOVE); |
29f59db3 | 7883 | |
eb580751 | 7884 | task_rq_unlock(rq, tsk, &rf); |
29f59db3 | 7885 | } |
7c941438 | 7886 | #endif /* CONFIG_CGROUP_SCHED */ |
29f59db3 | 7887 | |
a790de99 PT |
7888 | #ifdef CONFIG_RT_GROUP_SCHED |
7889 | /* | |
7890 | * Ensure that the real time constraints are schedulable. | |
7891 | */ | |
7892 | static DEFINE_MUTEX(rt_constraints_mutex); | |
9f0c1e56 | 7893 | |
9a7e0b18 PZ |
7894 | /* Must be called with tasklist_lock held */ |
7895 | static inline int tg_has_rt_tasks(struct task_group *tg) | |
b40b2e8e | 7896 | { |
9a7e0b18 | 7897 | struct task_struct *g, *p; |
b40b2e8e | 7898 | |
1fe89e1b PZ |
7899 | /* |
7900 | * Autogroups do not have RT tasks; see autogroup_create(). | |
7901 | */ | |
7902 | if (task_group_is_autogroup(tg)) | |
7903 | return 0; | |
7904 | ||
5d07f420 | 7905 | for_each_process_thread(g, p) { |
8651c658 | 7906 | if (rt_task(p) && task_group(p) == tg) |
9a7e0b18 | 7907 | return 1; |
5d07f420 | 7908 | } |
b40b2e8e | 7909 | |
9a7e0b18 PZ |
7910 | return 0; |
7911 | } | |
b40b2e8e | 7912 | |
9a7e0b18 PZ |
7913 | struct rt_schedulable_data { |
7914 | struct task_group *tg; | |
7915 | u64 rt_period; | |
7916 | u64 rt_runtime; | |
7917 | }; | |
b40b2e8e | 7918 | |
a790de99 | 7919 | static int tg_rt_schedulable(struct task_group *tg, void *data) |
9a7e0b18 PZ |
7920 | { |
7921 | struct rt_schedulable_data *d = data; | |
7922 | struct task_group *child; | |
7923 | unsigned long total, sum = 0; | |
7924 | u64 period, runtime; | |
b40b2e8e | 7925 | |
9a7e0b18 PZ |
7926 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
7927 | runtime = tg->rt_bandwidth.rt_runtime; | |
b40b2e8e | 7928 | |
9a7e0b18 PZ |
7929 | if (tg == d->tg) { |
7930 | period = d->rt_period; | |
7931 | runtime = d->rt_runtime; | |
b40b2e8e | 7932 | } |
b40b2e8e | 7933 | |
4653f803 PZ |
7934 | /* |
7935 | * Cannot have more runtime than the period. | |
7936 | */ | |
7937 | if (runtime > period && runtime != RUNTIME_INF) | |
7938 | return -EINVAL; | |
6f505b16 | 7939 | |
4653f803 PZ |
7940 | /* |
7941 | * Ensure we don't starve existing RT tasks. | |
7942 | */ | |
9a7e0b18 PZ |
7943 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
7944 | return -EBUSY; | |
6f505b16 | 7945 | |
9a7e0b18 | 7946 | total = to_ratio(period, runtime); |
6f505b16 | 7947 | |
4653f803 PZ |
7948 | /* |
7949 | * Nobody can have more than the global setting allows. | |
7950 | */ | |
7951 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) | |
7952 | return -EINVAL; | |
6f505b16 | 7953 | |
4653f803 PZ |
7954 | /* |
7955 | * The sum of our children's runtime should not exceed our own. | |
7956 | */ | |
9a7e0b18 PZ |
7957 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
7958 | period = ktime_to_ns(child->rt_bandwidth.rt_period); | |
7959 | runtime = child->rt_bandwidth.rt_runtime; | |
6f505b16 | 7960 | |
9a7e0b18 PZ |
7961 | if (child == d->tg) { |
7962 | period = d->rt_period; | |
7963 | runtime = d->rt_runtime; | |
7964 | } | |
6f505b16 | 7965 | |
9a7e0b18 | 7966 | sum += to_ratio(period, runtime); |
9f0c1e56 | 7967 | } |
6f505b16 | 7968 | |
9a7e0b18 PZ |
7969 | if (sum > total) |
7970 | return -EINVAL; | |
7971 | ||
7972 | return 0; | |
6f505b16 PZ |
7973 | } |
7974 | ||
9a7e0b18 | 7975 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
521f1a24 | 7976 | { |
8277434e PT |
7977 | int ret; |
7978 | ||
9a7e0b18 PZ |
7979 | struct rt_schedulable_data data = { |
7980 | .tg = tg, | |
7981 | .rt_period = period, | |
7982 | .rt_runtime = runtime, | |
7983 | }; | |
7984 | ||
8277434e PT |
7985 | rcu_read_lock(); |
7986 | ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); | |
7987 | rcu_read_unlock(); | |
7988 | ||
7989 | return ret; | |
521f1a24 DG |
7990 | } |
7991 | ||
ab84d31e | 7992 | static int tg_set_rt_bandwidth(struct task_group *tg, |
d0b27fa7 | 7993 | u64 rt_period, u64 rt_runtime) |
6f505b16 | 7994 | { |
ac086bc2 | 7995 | int i, err = 0; |
9f0c1e56 | 7996 | |
2636ed5f PZ |
7997 | /* |
7998 | * Disallowing the root group RT runtime is BAD, it would disallow the | |
7999 | * kernel creating (and or operating) RT threads. | |
8000 | */ | |
8001 | if (tg == &root_task_group && rt_runtime == 0) | |
8002 | return -EINVAL; | |
8003 | ||
8004 | /* No period doesn't make any sense. */ | |
8005 | if (rt_period == 0) | |
8006 | return -EINVAL; | |
8007 | ||
9f0c1e56 | 8008 | mutex_lock(&rt_constraints_mutex); |
521f1a24 | 8009 | read_lock(&tasklist_lock); |
9a7e0b18 PZ |
8010 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
8011 | if (err) | |
9f0c1e56 | 8012 | goto unlock; |
ac086bc2 | 8013 | |
0986b11b | 8014 | raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
d0b27fa7 PZ |
8015 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
8016 | tg->rt_bandwidth.rt_runtime = rt_runtime; | |
ac086bc2 PZ |
8017 | |
8018 | for_each_possible_cpu(i) { | |
8019 | struct rt_rq *rt_rq = tg->rt_rq[i]; | |
8020 | ||
0986b11b | 8021 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8022 | rt_rq->rt_runtime = rt_runtime; |
0986b11b | 8023 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8024 | } |
0986b11b | 8025 | raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
49246274 | 8026 | unlock: |
521f1a24 | 8027 | read_unlock(&tasklist_lock); |
9f0c1e56 PZ |
8028 | mutex_unlock(&rt_constraints_mutex); |
8029 | ||
8030 | return err; | |
6f505b16 PZ |
8031 | } |
8032 | ||
25cc7da7 | 8033 | static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
d0b27fa7 PZ |
8034 | { |
8035 | u64 rt_runtime, rt_period; | |
8036 | ||
8037 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
8038 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; | |
8039 | if (rt_runtime_us < 0) | |
8040 | rt_runtime = RUNTIME_INF; | |
8041 | ||
ab84d31e | 8042 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
8043 | } |
8044 | ||
25cc7da7 | 8045 | static long sched_group_rt_runtime(struct task_group *tg) |
9f0c1e56 PZ |
8046 | { |
8047 | u64 rt_runtime_us; | |
8048 | ||
d0b27fa7 | 8049 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
9f0c1e56 PZ |
8050 | return -1; |
8051 | ||
d0b27fa7 | 8052 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
9f0c1e56 PZ |
8053 | do_div(rt_runtime_us, NSEC_PER_USEC); |
8054 | return rt_runtime_us; | |
8055 | } | |
d0b27fa7 | 8056 | |
ce2f5fe4 | 8057 | static int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us) |
d0b27fa7 PZ |
8058 | { |
8059 | u64 rt_runtime, rt_period; | |
8060 | ||
ce2f5fe4 | 8061 | rt_period = rt_period_us * NSEC_PER_USEC; |
d0b27fa7 PZ |
8062 | rt_runtime = tg->rt_bandwidth.rt_runtime; |
8063 | ||
ab84d31e | 8064 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
8065 | } |
8066 | ||
25cc7da7 | 8067 | static long sched_group_rt_period(struct task_group *tg) |
d0b27fa7 PZ |
8068 | { |
8069 | u64 rt_period_us; | |
8070 | ||
8071 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
8072 | do_div(rt_period_us, NSEC_PER_USEC); | |
8073 | return rt_period_us; | |
8074 | } | |
332ac17e | 8075 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 8076 | |
332ac17e | 8077 | #ifdef CONFIG_RT_GROUP_SCHED |
d0b27fa7 PZ |
8078 | static int sched_rt_global_constraints(void) |
8079 | { | |
8080 | int ret = 0; | |
8081 | ||
8082 | mutex_lock(&rt_constraints_mutex); | |
9a7e0b18 | 8083 | read_lock(&tasklist_lock); |
4653f803 | 8084 | ret = __rt_schedulable(NULL, 0, 0); |
9a7e0b18 | 8085 | read_unlock(&tasklist_lock); |
d0b27fa7 PZ |
8086 | mutex_unlock(&rt_constraints_mutex); |
8087 | ||
8088 | return ret; | |
8089 | } | |
54e99124 | 8090 | |
25cc7da7 | 8091 | static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
54e99124 DG |
8092 | { |
8093 | /* Don't accept realtime tasks when there is no way for them to run */ | |
8094 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) | |
8095 | return 0; | |
8096 | ||
8097 | return 1; | |
8098 | } | |
8099 | ||
6d6bc0ad | 8100 | #else /* !CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 PZ |
8101 | static int sched_rt_global_constraints(void) |
8102 | { | |
ac086bc2 | 8103 | unsigned long flags; |
8c5e9554 | 8104 | int i; |
ec5d4989 | 8105 | |
0986b11b | 8106 | raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 PZ |
8107 | for_each_possible_cpu(i) { |
8108 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; | |
8109 | ||
0986b11b | 8110 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8111 | rt_rq->rt_runtime = global_rt_runtime(); |
0986b11b | 8112 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8113 | } |
0986b11b | 8114 | raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 | 8115 | |
8c5e9554 | 8116 | return 0; |
d0b27fa7 | 8117 | } |
6d6bc0ad | 8118 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 8119 | |
a1963b81 | 8120 | static int sched_dl_global_validate(void) |
332ac17e | 8121 | { |
1724813d PZ |
8122 | u64 runtime = global_rt_runtime(); |
8123 | u64 period = global_rt_period(); | |
332ac17e | 8124 | u64 new_bw = to_ratio(period, runtime); |
f10e00f4 | 8125 | struct dl_bw *dl_b; |
1724813d | 8126 | int cpu, ret = 0; |
49516342 | 8127 | unsigned long flags; |
332ac17e DF |
8128 | |
8129 | /* | |
8130 | * Here we want to check the bandwidth not being set to some | |
8131 | * value smaller than the currently allocated bandwidth in | |
8132 | * any of the root_domains. | |
8133 | * | |
8134 | * FIXME: Cycling on all the CPUs is overdoing, but simpler than | |
8135 | * cycling on root_domains... Discussion on different/better | |
8136 | * solutions is welcome! | |
8137 | */ | |
1724813d | 8138 | for_each_possible_cpu(cpu) { |
f10e00f4 KT |
8139 | rcu_read_lock_sched(); |
8140 | dl_b = dl_bw_of(cpu); | |
332ac17e | 8141 | |
49516342 | 8142 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
1724813d PZ |
8143 | if (new_bw < dl_b->total_bw) |
8144 | ret = -EBUSY; | |
49516342 | 8145 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
1724813d | 8146 | |
f10e00f4 KT |
8147 | rcu_read_unlock_sched(); |
8148 | ||
1724813d PZ |
8149 | if (ret) |
8150 | break; | |
332ac17e DF |
8151 | } |
8152 | ||
1724813d | 8153 | return ret; |
332ac17e DF |
8154 | } |
8155 | ||
1724813d | 8156 | static void sched_dl_do_global(void) |
ce0dbbbb | 8157 | { |
1724813d | 8158 | u64 new_bw = -1; |
f10e00f4 | 8159 | struct dl_bw *dl_b; |
1724813d | 8160 | int cpu; |
49516342 | 8161 | unsigned long flags; |
ce0dbbbb | 8162 | |
1724813d PZ |
8163 | def_dl_bandwidth.dl_period = global_rt_period(); |
8164 | def_dl_bandwidth.dl_runtime = global_rt_runtime(); | |
8165 | ||
8166 | if (global_rt_runtime() != RUNTIME_INF) | |
8167 | new_bw = to_ratio(global_rt_period(), global_rt_runtime()); | |
8168 | ||
8169 | /* | |
8170 | * FIXME: As above... | |
8171 | */ | |
8172 | for_each_possible_cpu(cpu) { | |
f10e00f4 KT |
8173 | rcu_read_lock_sched(); |
8174 | dl_b = dl_bw_of(cpu); | |
1724813d | 8175 | |
49516342 | 8176 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
1724813d | 8177 | dl_b->bw = new_bw; |
49516342 | 8178 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
f10e00f4 KT |
8179 | |
8180 | rcu_read_unlock_sched(); | |
ce0dbbbb | 8181 | } |
1724813d PZ |
8182 | } |
8183 | ||
8184 | static int sched_rt_global_validate(void) | |
8185 | { | |
8186 | if (sysctl_sched_rt_period <= 0) | |
8187 | return -EINVAL; | |
8188 | ||
e9e7cb38 JL |
8189 | if ((sysctl_sched_rt_runtime != RUNTIME_INF) && |
8190 | (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) | |
1724813d PZ |
8191 | return -EINVAL; |
8192 | ||
8193 | return 0; | |
8194 | } | |
8195 | ||
8196 | static void sched_rt_do_global(void) | |
8197 | { | |
8198 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); | |
8199 | def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); | |
ce0dbbbb CW |
8200 | } |
8201 | ||
d0b27fa7 | 8202 | int sched_rt_handler(struct ctl_table *table, int write, |
8d65af78 | 8203 | void __user *buffer, size_t *lenp, |
d0b27fa7 PZ |
8204 | loff_t *ppos) |
8205 | { | |
d0b27fa7 PZ |
8206 | int old_period, old_runtime; |
8207 | static DEFINE_MUTEX(mutex); | |
1724813d | 8208 | int ret; |
d0b27fa7 PZ |
8209 | |
8210 | mutex_lock(&mutex); | |
8211 | old_period = sysctl_sched_rt_period; | |
8212 | old_runtime = sysctl_sched_rt_runtime; | |
8213 | ||
8d65af78 | 8214 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
d0b27fa7 PZ |
8215 | |
8216 | if (!ret && write) { | |
1724813d PZ |
8217 | ret = sched_rt_global_validate(); |
8218 | if (ret) | |
8219 | goto undo; | |
8220 | ||
a1963b81 | 8221 | ret = sched_dl_global_validate(); |
1724813d PZ |
8222 | if (ret) |
8223 | goto undo; | |
8224 | ||
a1963b81 | 8225 | ret = sched_rt_global_constraints(); |
1724813d PZ |
8226 | if (ret) |
8227 | goto undo; | |
8228 | ||
8229 | sched_rt_do_global(); | |
8230 | sched_dl_do_global(); | |
8231 | } | |
8232 | if (0) { | |
8233 | undo: | |
8234 | sysctl_sched_rt_period = old_period; | |
8235 | sysctl_sched_rt_runtime = old_runtime; | |
d0b27fa7 PZ |
8236 | } |
8237 | mutex_unlock(&mutex); | |
8238 | ||
8239 | return ret; | |
8240 | } | |
68318b8e | 8241 | |
1724813d | 8242 | int sched_rr_handler(struct ctl_table *table, int write, |
332ac17e DF |
8243 | void __user *buffer, size_t *lenp, |
8244 | loff_t *ppos) | |
8245 | { | |
8246 | int ret; | |
332ac17e | 8247 | static DEFINE_MUTEX(mutex); |
332ac17e DF |
8248 | |
8249 | mutex_lock(&mutex); | |
332ac17e | 8250 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
1724813d PZ |
8251 | /* make sure that internally we keep jiffies */ |
8252 | /* also, writing zero resets timeslice to default */ | |
332ac17e | 8253 | if (!ret && write) { |
1724813d PZ |
8254 | sched_rr_timeslice = sched_rr_timeslice <= 0 ? |
8255 | RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); | |
332ac17e DF |
8256 | } |
8257 | mutex_unlock(&mutex); | |
332ac17e DF |
8258 | return ret; |
8259 | } | |
8260 | ||
052f1dc7 | 8261 | #ifdef CONFIG_CGROUP_SCHED |
68318b8e | 8262 | |
a7c6d554 | 8263 | static inline struct task_group *css_tg(struct cgroup_subsys_state *css) |
68318b8e | 8264 | { |
a7c6d554 | 8265 | return css ? container_of(css, struct task_group, css) : NULL; |
68318b8e SV |
8266 | } |
8267 | ||
eb95419b TH |
8268 | static struct cgroup_subsys_state * |
8269 | cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) | |
68318b8e | 8270 | { |
eb95419b TH |
8271 | struct task_group *parent = css_tg(parent_css); |
8272 | struct task_group *tg; | |
68318b8e | 8273 | |
eb95419b | 8274 | if (!parent) { |
68318b8e | 8275 | /* This is early initialization for the top cgroup */ |
07e06b01 | 8276 | return &root_task_group.css; |
68318b8e SV |
8277 | } |
8278 | ||
ec7dc8ac | 8279 | tg = sched_create_group(parent); |
68318b8e SV |
8280 | if (IS_ERR(tg)) |
8281 | return ERR_PTR(-ENOMEM); | |
8282 | ||
2f5177f0 PZ |
8283 | sched_online_group(tg, parent); |
8284 | ||
68318b8e SV |
8285 | return &tg->css; |
8286 | } | |
8287 | ||
2f5177f0 | 8288 | static void cpu_cgroup_css_released(struct cgroup_subsys_state *css) |
ace783b9 | 8289 | { |
eb95419b | 8290 | struct task_group *tg = css_tg(css); |
ace783b9 | 8291 | |
2f5177f0 | 8292 | sched_offline_group(tg); |
ace783b9 LZ |
8293 | } |
8294 | ||
eb95419b | 8295 | static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) |
68318b8e | 8296 | { |
eb95419b | 8297 | struct task_group *tg = css_tg(css); |
68318b8e | 8298 | |
2f5177f0 PZ |
8299 | /* |
8300 | * Relies on the RCU grace period between css_released() and this. | |
8301 | */ | |
8302 | sched_free_group(tg); | |
ace783b9 LZ |
8303 | } |
8304 | ||
ea86cb4b VG |
8305 | /* |
8306 | * This is called before wake_up_new_task(), therefore we really only | |
8307 | * have to set its group bits, all the other stuff does not apply. | |
8308 | */ | |
b53202e6 | 8309 | static void cpu_cgroup_fork(struct task_struct *task) |
eeb61e53 | 8310 | { |
ea86cb4b VG |
8311 | struct rq_flags rf; |
8312 | struct rq *rq; | |
8313 | ||
8314 | rq = task_rq_lock(task, &rf); | |
8315 | ||
8316 | sched_change_group(task, TASK_SET_GROUP); | |
8317 | ||
8318 | task_rq_unlock(rq, task, &rf); | |
eeb61e53 KT |
8319 | } |
8320 | ||
1f7dd3e5 | 8321 | static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) |
68318b8e | 8322 | { |
bb9d97b6 | 8323 | struct task_struct *task; |
1f7dd3e5 | 8324 | struct cgroup_subsys_state *css; |
7dc603c9 | 8325 | int ret = 0; |
bb9d97b6 | 8326 | |
1f7dd3e5 | 8327 | cgroup_taskset_for_each(task, css, tset) { |
b68aa230 | 8328 | #ifdef CONFIG_RT_GROUP_SCHED |
eb95419b | 8329 | if (!sched_rt_can_attach(css_tg(css), task)) |
bb9d97b6 | 8330 | return -EINVAL; |
b68aa230 | 8331 | #else |
bb9d97b6 TH |
8332 | /* We don't support RT-tasks being in separate groups */ |
8333 | if (task->sched_class != &fair_sched_class) | |
8334 | return -EINVAL; | |
b68aa230 | 8335 | #endif |
7dc603c9 PZ |
8336 | /* |
8337 | * Serialize against wake_up_new_task() such that if its | |
8338 | * running, we're sure to observe its full state. | |
8339 | */ | |
8340 | raw_spin_lock_irq(&task->pi_lock); | |
8341 | /* | |
8342 | * Avoid calling sched_move_task() before wake_up_new_task() | |
8343 | * has happened. This would lead to problems with PELT, due to | |
8344 | * move wanting to detach+attach while we're not attached yet. | |
8345 | */ | |
8346 | if (task->state == TASK_NEW) | |
8347 | ret = -EINVAL; | |
8348 | raw_spin_unlock_irq(&task->pi_lock); | |
8349 | ||
8350 | if (ret) | |
8351 | break; | |
bb9d97b6 | 8352 | } |
7dc603c9 | 8353 | return ret; |
be367d09 | 8354 | } |
68318b8e | 8355 | |
1f7dd3e5 | 8356 | static void cpu_cgroup_attach(struct cgroup_taskset *tset) |
68318b8e | 8357 | { |
bb9d97b6 | 8358 | struct task_struct *task; |
1f7dd3e5 | 8359 | struct cgroup_subsys_state *css; |
bb9d97b6 | 8360 | |
1f7dd3e5 | 8361 | cgroup_taskset_for_each(task, css, tset) |
bb9d97b6 | 8362 | sched_move_task(task); |
68318b8e SV |
8363 | } |
8364 | ||
052f1dc7 | 8365 | #ifdef CONFIG_FAIR_GROUP_SCHED |
182446d0 TH |
8366 | static int cpu_shares_write_u64(struct cgroup_subsys_state *css, |
8367 | struct cftype *cftype, u64 shareval) | |
68318b8e | 8368 | { |
182446d0 | 8369 | return sched_group_set_shares(css_tg(css), scale_load(shareval)); |
68318b8e SV |
8370 | } |
8371 | ||
182446d0 TH |
8372 | static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, |
8373 | struct cftype *cft) | |
68318b8e | 8374 | { |
182446d0 | 8375 | struct task_group *tg = css_tg(css); |
68318b8e | 8376 | |
c8b28116 | 8377 | return (u64) scale_load_down(tg->shares); |
68318b8e | 8378 | } |
ab84d31e PT |
8379 | |
8380 | #ifdef CONFIG_CFS_BANDWIDTH | |
a790de99 PT |
8381 | static DEFINE_MUTEX(cfs_constraints_mutex); |
8382 | ||
ab84d31e PT |
8383 | const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ |
8384 | const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ | |
8385 | ||
a790de99 PT |
8386 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); |
8387 | ||
ab84d31e PT |
8388 | static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) |
8389 | { | |
56f570e5 | 8390 | int i, ret = 0, runtime_enabled, runtime_was_enabled; |
029632fb | 8391 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
ab84d31e PT |
8392 | |
8393 | if (tg == &root_task_group) | |
8394 | return -EINVAL; | |
8395 | ||
8396 | /* | |
8397 | * Ensure we have at some amount of bandwidth every period. This is | |
8398 | * to prevent reaching a state of large arrears when throttled via | |
8399 | * entity_tick() resulting in prolonged exit starvation. | |
8400 | */ | |
8401 | if (quota < min_cfs_quota_period || period < min_cfs_quota_period) | |
8402 | return -EINVAL; | |
8403 | ||
8404 | /* | |
8405 | * Likewise, bound things on the otherside by preventing insane quota | |
8406 | * periods. This also allows us to normalize in computing quota | |
8407 | * feasibility. | |
8408 | */ | |
8409 | if (period > max_cfs_quota_period) | |
8410 | return -EINVAL; | |
8411 | ||
0e59bdae KT |
8412 | /* |
8413 | * Prevent race between setting of cfs_rq->runtime_enabled and | |
8414 | * unthrottle_offline_cfs_rqs(). | |
8415 | */ | |
8416 | get_online_cpus(); | |
a790de99 PT |
8417 | mutex_lock(&cfs_constraints_mutex); |
8418 | ret = __cfs_schedulable(tg, period, quota); | |
8419 | if (ret) | |
8420 | goto out_unlock; | |
8421 | ||
58088ad0 | 8422 | runtime_enabled = quota != RUNTIME_INF; |
56f570e5 | 8423 | runtime_was_enabled = cfs_b->quota != RUNTIME_INF; |
1ee14e6c BS |
8424 | /* |
8425 | * If we need to toggle cfs_bandwidth_used, off->on must occur | |
8426 | * before making related changes, and on->off must occur afterwards | |
8427 | */ | |
8428 | if (runtime_enabled && !runtime_was_enabled) | |
8429 | cfs_bandwidth_usage_inc(); | |
ab84d31e PT |
8430 | raw_spin_lock_irq(&cfs_b->lock); |
8431 | cfs_b->period = ns_to_ktime(period); | |
8432 | cfs_b->quota = quota; | |
58088ad0 | 8433 | |
a9cf55b2 | 8434 | __refill_cfs_bandwidth_runtime(cfs_b); |
58088ad0 | 8435 | /* restart the period timer (if active) to handle new period expiry */ |
77a4d1a1 PZ |
8436 | if (runtime_enabled) |
8437 | start_cfs_bandwidth(cfs_b); | |
ab84d31e PT |
8438 | raw_spin_unlock_irq(&cfs_b->lock); |
8439 | ||
0e59bdae | 8440 | for_each_online_cpu(i) { |
ab84d31e | 8441 | struct cfs_rq *cfs_rq = tg->cfs_rq[i]; |
029632fb | 8442 | struct rq *rq = cfs_rq->rq; |
ab84d31e PT |
8443 | |
8444 | raw_spin_lock_irq(&rq->lock); | |
58088ad0 | 8445 | cfs_rq->runtime_enabled = runtime_enabled; |
ab84d31e | 8446 | cfs_rq->runtime_remaining = 0; |
671fd9da | 8447 | |
029632fb | 8448 | if (cfs_rq->throttled) |
671fd9da | 8449 | unthrottle_cfs_rq(cfs_rq); |
ab84d31e PT |
8450 | raw_spin_unlock_irq(&rq->lock); |
8451 | } | |
1ee14e6c BS |
8452 | if (runtime_was_enabled && !runtime_enabled) |
8453 | cfs_bandwidth_usage_dec(); | |
a790de99 PT |
8454 | out_unlock: |
8455 | mutex_unlock(&cfs_constraints_mutex); | |
0e59bdae | 8456 | put_online_cpus(); |
ab84d31e | 8457 | |
a790de99 | 8458 | return ret; |
ab84d31e PT |
8459 | } |
8460 | ||
8461 | int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) | |
8462 | { | |
8463 | u64 quota, period; | |
8464 | ||
029632fb | 8465 | period = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
8466 | if (cfs_quota_us < 0) |
8467 | quota = RUNTIME_INF; | |
8468 | else | |
8469 | quota = (u64)cfs_quota_us * NSEC_PER_USEC; | |
8470 | ||
8471 | return tg_set_cfs_bandwidth(tg, period, quota); | |
8472 | } | |
8473 | ||
8474 | long tg_get_cfs_quota(struct task_group *tg) | |
8475 | { | |
8476 | u64 quota_us; | |
8477 | ||
029632fb | 8478 | if (tg->cfs_bandwidth.quota == RUNTIME_INF) |
ab84d31e PT |
8479 | return -1; |
8480 | ||
029632fb | 8481 | quota_us = tg->cfs_bandwidth.quota; |
ab84d31e PT |
8482 | do_div(quota_us, NSEC_PER_USEC); |
8483 | ||
8484 | return quota_us; | |
8485 | } | |
8486 | ||
8487 | int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) | |
8488 | { | |
8489 | u64 quota, period; | |
8490 | ||
8491 | period = (u64)cfs_period_us * NSEC_PER_USEC; | |
029632fb | 8492 | quota = tg->cfs_bandwidth.quota; |
ab84d31e | 8493 | |
ab84d31e PT |
8494 | return tg_set_cfs_bandwidth(tg, period, quota); |
8495 | } | |
8496 | ||
8497 | long tg_get_cfs_period(struct task_group *tg) | |
8498 | { | |
8499 | u64 cfs_period_us; | |
8500 | ||
029632fb | 8501 | cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
8502 | do_div(cfs_period_us, NSEC_PER_USEC); |
8503 | ||
8504 | return cfs_period_us; | |
8505 | } | |
8506 | ||
182446d0 TH |
8507 | static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, |
8508 | struct cftype *cft) | |
ab84d31e | 8509 | { |
182446d0 | 8510 | return tg_get_cfs_quota(css_tg(css)); |
ab84d31e PT |
8511 | } |
8512 | ||
182446d0 TH |
8513 | static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, |
8514 | struct cftype *cftype, s64 cfs_quota_us) | |
ab84d31e | 8515 | { |
182446d0 | 8516 | return tg_set_cfs_quota(css_tg(css), cfs_quota_us); |
ab84d31e PT |
8517 | } |
8518 | ||
182446d0 TH |
8519 | static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, |
8520 | struct cftype *cft) | |
ab84d31e | 8521 | { |
182446d0 | 8522 | return tg_get_cfs_period(css_tg(css)); |
ab84d31e PT |
8523 | } |
8524 | ||
182446d0 TH |
8525 | static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, |
8526 | struct cftype *cftype, u64 cfs_period_us) | |
ab84d31e | 8527 | { |
182446d0 | 8528 | return tg_set_cfs_period(css_tg(css), cfs_period_us); |
ab84d31e PT |
8529 | } |
8530 | ||
a790de99 PT |
8531 | struct cfs_schedulable_data { |
8532 | struct task_group *tg; | |
8533 | u64 period, quota; | |
8534 | }; | |
8535 | ||
8536 | /* | |
8537 | * normalize group quota/period to be quota/max_period | |
8538 | * note: units are usecs | |
8539 | */ | |
8540 | static u64 normalize_cfs_quota(struct task_group *tg, | |
8541 | struct cfs_schedulable_data *d) | |
8542 | { | |
8543 | u64 quota, period; | |
8544 | ||
8545 | if (tg == d->tg) { | |
8546 | period = d->period; | |
8547 | quota = d->quota; | |
8548 | } else { | |
8549 | period = tg_get_cfs_period(tg); | |
8550 | quota = tg_get_cfs_quota(tg); | |
8551 | } | |
8552 | ||
8553 | /* note: these should typically be equivalent */ | |
8554 | if (quota == RUNTIME_INF || quota == -1) | |
8555 | return RUNTIME_INF; | |
8556 | ||
8557 | return to_ratio(period, quota); | |
8558 | } | |
8559 | ||
8560 | static int tg_cfs_schedulable_down(struct task_group *tg, void *data) | |
8561 | { | |
8562 | struct cfs_schedulable_data *d = data; | |
029632fb | 8563 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
a790de99 PT |
8564 | s64 quota = 0, parent_quota = -1; |
8565 | ||
8566 | if (!tg->parent) { | |
8567 | quota = RUNTIME_INF; | |
8568 | } else { | |
029632fb | 8569 | struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; |
a790de99 PT |
8570 | |
8571 | quota = normalize_cfs_quota(tg, d); | |
9c58c79a | 8572 | parent_quota = parent_b->hierarchical_quota; |
a790de99 PT |
8573 | |
8574 | /* | |
8575 | * ensure max(child_quota) <= parent_quota, inherit when no | |
8576 | * limit is set | |
8577 | */ | |
8578 | if (quota == RUNTIME_INF) | |
8579 | quota = parent_quota; | |
8580 | else if (parent_quota != RUNTIME_INF && quota > parent_quota) | |
8581 | return -EINVAL; | |
8582 | } | |
9c58c79a | 8583 | cfs_b->hierarchical_quota = quota; |
a790de99 PT |
8584 | |
8585 | return 0; | |
8586 | } | |
8587 | ||
8588 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) | |
8589 | { | |
8277434e | 8590 | int ret; |
a790de99 PT |
8591 | struct cfs_schedulable_data data = { |
8592 | .tg = tg, | |
8593 | .period = period, | |
8594 | .quota = quota, | |
8595 | }; | |
8596 | ||
8597 | if (quota != RUNTIME_INF) { | |
8598 | do_div(data.period, NSEC_PER_USEC); | |
8599 | do_div(data.quota, NSEC_PER_USEC); | |
8600 | } | |
8601 | ||
8277434e PT |
8602 | rcu_read_lock(); |
8603 | ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); | |
8604 | rcu_read_unlock(); | |
8605 | ||
8606 | return ret; | |
a790de99 | 8607 | } |
e8da1b18 | 8608 | |
2da8ca82 | 8609 | static int cpu_stats_show(struct seq_file *sf, void *v) |
e8da1b18 | 8610 | { |
2da8ca82 | 8611 | struct task_group *tg = css_tg(seq_css(sf)); |
029632fb | 8612 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
e8da1b18 | 8613 | |
44ffc75b TH |
8614 | seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); |
8615 | seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); | |
8616 | seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); | |
e8da1b18 NR |
8617 | |
8618 | return 0; | |
8619 | } | |
ab84d31e | 8620 | #endif /* CONFIG_CFS_BANDWIDTH */ |
6d6bc0ad | 8621 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e | 8622 | |
052f1dc7 | 8623 | #ifdef CONFIG_RT_GROUP_SCHED |
182446d0 TH |
8624 | static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, |
8625 | struct cftype *cft, s64 val) | |
6f505b16 | 8626 | { |
182446d0 | 8627 | return sched_group_set_rt_runtime(css_tg(css), val); |
6f505b16 PZ |
8628 | } |
8629 | ||
182446d0 TH |
8630 | static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, |
8631 | struct cftype *cft) | |
6f505b16 | 8632 | { |
182446d0 | 8633 | return sched_group_rt_runtime(css_tg(css)); |
6f505b16 | 8634 | } |
d0b27fa7 | 8635 | |
182446d0 TH |
8636 | static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, |
8637 | struct cftype *cftype, u64 rt_period_us) | |
d0b27fa7 | 8638 | { |
182446d0 | 8639 | return sched_group_set_rt_period(css_tg(css), rt_period_us); |
d0b27fa7 PZ |
8640 | } |
8641 | ||
182446d0 TH |
8642 | static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, |
8643 | struct cftype *cft) | |
d0b27fa7 | 8644 | { |
182446d0 | 8645 | return sched_group_rt_period(css_tg(css)); |
d0b27fa7 | 8646 | } |
6d6bc0ad | 8647 | #endif /* CONFIG_RT_GROUP_SCHED */ |
6f505b16 | 8648 | |
fe5c7cc2 | 8649 | static struct cftype cpu_files[] = { |
052f1dc7 | 8650 | #ifdef CONFIG_FAIR_GROUP_SCHED |
fe5c7cc2 PM |
8651 | { |
8652 | .name = "shares", | |
f4c753b7 PM |
8653 | .read_u64 = cpu_shares_read_u64, |
8654 | .write_u64 = cpu_shares_write_u64, | |
fe5c7cc2 | 8655 | }, |
052f1dc7 | 8656 | #endif |
ab84d31e PT |
8657 | #ifdef CONFIG_CFS_BANDWIDTH |
8658 | { | |
8659 | .name = "cfs_quota_us", | |
8660 | .read_s64 = cpu_cfs_quota_read_s64, | |
8661 | .write_s64 = cpu_cfs_quota_write_s64, | |
8662 | }, | |
8663 | { | |
8664 | .name = "cfs_period_us", | |
8665 | .read_u64 = cpu_cfs_period_read_u64, | |
8666 | .write_u64 = cpu_cfs_period_write_u64, | |
8667 | }, | |
e8da1b18 NR |
8668 | { |
8669 | .name = "stat", | |
2da8ca82 | 8670 | .seq_show = cpu_stats_show, |
e8da1b18 | 8671 | }, |
ab84d31e | 8672 | #endif |
052f1dc7 | 8673 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 8674 | { |
9f0c1e56 | 8675 | .name = "rt_runtime_us", |
06ecb27c PM |
8676 | .read_s64 = cpu_rt_runtime_read, |
8677 | .write_s64 = cpu_rt_runtime_write, | |
6f505b16 | 8678 | }, |
d0b27fa7 PZ |
8679 | { |
8680 | .name = "rt_period_us", | |
f4c753b7 PM |
8681 | .read_u64 = cpu_rt_period_read_uint, |
8682 | .write_u64 = cpu_rt_period_write_uint, | |
d0b27fa7 | 8683 | }, |
052f1dc7 | 8684 | #endif |
4baf6e33 | 8685 | { } /* terminate */ |
68318b8e SV |
8686 | }; |
8687 | ||
073219e9 | 8688 | struct cgroup_subsys cpu_cgrp_subsys = { |
92fb9748 | 8689 | .css_alloc = cpu_cgroup_css_alloc, |
2f5177f0 | 8690 | .css_released = cpu_cgroup_css_released, |
92fb9748 | 8691 | .css_free = cpu_cgroup_css_free, |
eeb61e53 | 8692 | .fork = cpu_cgroup_fork, |
bb9d97b6 TH |
8693 | .can_attach = cpu_cgroup_can_attach, |
8694 | .attach = cpu_cgroup_attach, | |
5577964e | 8695 | .legacy_cftypes = cpu_files, |
b38e42e9 | 8696 | .early_init = true, |
68318b8e SV |
8697 | }; |
8698 | ||
052f1dc7 | 8699 | #endif /* CONFIG_CGROUP_SCHED */ |
d842de87 | 8700 | |
b637a328 PM |
8701 | void dump_cpu_task(int cpu) |
8702 | { | |
8703 | pr_info("Task dump for CPU %d:\n", cpu); | |
8704 | sched_show_task(cpu_curr(cpu)); | |
8705 | } | |
ed82b8a1 AK |
8706 | |
8707 | /* | |
8708 | * Nice levels are multiplicative, with a gentle 10% change for every | |
8709 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
8710 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
8711 | * that remained on nice 0. | |
8712 | * | |
8713 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
8714 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
8715 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. | |
8716 | * If a task goes up by ~10% and another task goes down by ~10% then | |
8717 | * the relative distance between them is ~25%.) | |
8718 | */ | |
8719 | const int sched_prio_to_weight[40] = { | |
8720 | /* -20 */ 88761, 71755, 56483, 46273, 36291, | |
8721 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
8722 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
8723 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
8724 | /* 0 */ 1024, 820, 655, 526, 423, | |
8725 | /* 5 */ 335, 272, 215, 172, 137, | |
8726 | /* 10 */ 110, 87, 70, 56, 45, | |
8727 | /* 15 */ 36, 29, 23, 18, 15, | |
8728 | }; | |
8729 | ||
8730 | /* | |
8731 | * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated. | |
8732 | * | |
8733 | * In cases where the weight does not change often, we can use the | |
8734 | * precalculated inverse to speed up arithmetics by turning divisions | |
8735 | * into multiplications: | |
8736 | */ | |
8737 | const u32 sched_prio_to_wmult[40] = { | |
8738 | /* -20 */ 48388, 59856, 76040, 92818, 118348, | |
8739 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
8740 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
8741 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
8742 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
8743 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
8744 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
8745 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
8746 | }; |