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Commit | Line | Data |
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1da177e4 | 1 | /* |
391e43da | 2 | * kernel/sched/core.c |
1da177e4 LT |
3 | * |
4 | * Kernel scheduler and related syscalls | |
5 | * | |
6 | * Copyright (C) 1991-2002 Linus Torvalds | |
7 | * | |
8 | * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and | |
9 | * make semaphores SMP safe | |
10 | * 1998-11-19 Implemented schedule_timeout() and related stuff | |
11 | * by Andrea Arcangeli | |
12 | * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: | |
13 | * hybrid priority-list and round-robin design with | |
14 | * an array-switch method of distributing timeslices | |
15 | * and per-CPU runqueues. Cleanups and useful suggestions | |
16 | * by Davide Libenzi, preemptible kernel bits by Robert Love. | |
17 | * 2003-09-03 Interactivity tuning by Con Kolivas. | |
18 | * 2004-04-02 Scheduler domains code by Nick Piggin | |
c31f2e8a IM |
19 | * 2007-04-15 Work begun on replacing all interactivity tuning with a |
20 | * fair scheduling design by Con Kolivas. | |
21 | * 2007-05-05 Load balancing (smp-nice) and other improvements | |
22 | * by Peter Williams | |
23 | * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith | |
24 | * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri | |
b9131769 IM |
25 | * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, |
26 | * Thomas Gleixner, Mike Kravetz | |
1da177e4 LT |
27 | */ |
28 | ||
29 | #include <linux/mm.h> | |
30 | #include <linux/module.h> | |
31 | #include <linux/nmi.h> | |
32 | #include <linux/init.h> | |
dff06c15 | 33 | #include <linux/uaccess.h> |
1da177e4 | 34 | #include <linux/highmem.h> |
1da177e4 LT |
35 | #include <asm/mmu_context.h> |
36 | #include <linux/interrupt.h> | |
c59ede7b | 37 | #include <linux/capability.h> |
1da177e4 LT |
38 | #include <linux/completion.h> |
39 | #include <linux/kernel_stat.h> | |
9a11b49a | 40 | #include <linux/debug_locks.h> |
cdd6c482 | 41 | #include <linux/perf_event.h> |
1da177e4 LT |
42 | #include <linux/security.h> |
43 | #include <linux/notifier.h> | |
44 | #include <linux/profile.h> | |
7dfb7103 | 45 | #include <linux/freezer.h> |
198e2f18 | 46 | #include <linux/vmalloc.h> |
1da177e4 LT |
47 | #include <linux/blkdev.h> |
48 | #include <linux/delay.h> | |
b488893a | 49 | #include <linux/pid_namespace.h> |
1da177e4 LT |
50 | #include <linux/smp.h> |
51 | #include <linux/threads.h> | |
52 | #include <linux/timer.h> | |
53 | #include <linux/rcupdate.h> | |
54 | #include <linux/cpu.h> | |
55 | #include <linux/cpuset.h> | |
56 | #include <linux/percpu.h> | |
b5aadf7f | 57 | #include <linux/proc_fs.h> |
1da177e4 | 58 | #include <linux/seq_file.h> |
e692ab53 | 59 | #include <linux/sysctl.h> |
1da177e4 LT |
60 | #include <linux/syscalls.h> |
61 | #include <linux/times.h> | |
8f0ab514 | 62 | #include <linux/tsacct_kern.h> |
c6fd91f0 | 63 | #include <linux/kprobes.h> |
0ff92245 | 64 | #include <linux/delayacct.h> |
dff06c15 | 65 | #include <linux/unistd.h> |
f5ff8422 | 66 | #include <linux/pagemap.h> |
8f4d37ec | 67 | #include <linux/hrtimer.h> |
30914a58 | 68 | #include <linux/tick.h> |
f00b45c1 PZ |
69 | #include <linux/debugfs.h> |
70 | #include <linux/ctype.h> | |
6cd8a4bb | 71 | #include <linux/ftrace.h> |
5a0e3ad6 | 72 | #include <linux/slab.h> |
f1c6f1a7 | 73 | #include <linux/init_task.h> |
40401530 | 74 | #include <linux/binfmts.h> |
91d1aa43 | 75 | #include <linux/context_tracking.h> |
52f5684c | 76 | #include <linux/compiler.h> |
1da177e4 | 77 | |
96f951ed | 78 | #include <asm/switch_to.h> |
5517d86b | 79 | #include <asm/tlb.h> |
838225b4 | 80 | #include <asm/irq_regs.h> |
db7e527d | 81 | #include <asm/mutex.h> |
e6e6685a GC |
82 | #ifdef CONFIG_PARAVIRT |
83 | #include <asm/paravirt.h> | |
84 | #endif | |
1da177e4 | 85 | |
029632fb | 86 | #include "sched.h" |
ea138446 | 87 | #include "../workqueue_internal.h" |
29d5e047 | 88 | #include "../smpboot.h" |
6e0534f2 | 89 | |
a8d154b0 | 90 | #define CREATE_TRACE_POINTS |
ad8d75ff | 91 | #include <trace/events/sched.h> |
a8d154b0 | 92 | |
029632fb PZ |
93 | DEFINE_MUTEX(sched_domains_mutex); |
94 | DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); | |
dc61b1d6 | 95 | |
fe44d621 | 96 | static void update_rq_clock_task(struct rq *rq, s64 delta); |
305e6835 | 97 | |
029632fb | 98 | void update_rq_clock(struct rq *rq) |
3e51f33f | 99 | { |
fe44d621 | 100 | s64 delta; |
305e6835 | 101 | |
9edfbfed PZ |
102 | lockdep_assert_held(&rq->lock); |
103 | ||
104 | if (rq->clock_skip_update & RQCF_ACT_SKIP) | |
f26f9aff | 105 | return; |
aa483808 | 106 | |
fe44d621 | 107 | delta = sched_clock_cpu(cpu_of(rq)) - rq->clock; |
4036ac15 MG |
108 | if (delta < 0) |
109 | return; | |
fe44d621 PZ |
110 | rq->clock += delta; |
111 | update_rq_clock_task(rq, delta); | |
3e51f33f PZ |
112 | } |
113 | ||
bf5c91ba IM |
114 | /* |
115 | * Debugging: various feature bits | |
116 | */ | |
f00b45c1 | 117 | |
f00b45c1 PZ |
118 | #define SCHED_FEAT(name, enabled) \ |
119 | (1UL << __SCHED_FEAT_##name) * enabled | | |
120 | ||
bf5c91ba | 121 | const_debug unsigned int sysctl_sched_features = |
391e43da | 122 | #include "features.h" |
f00b45c1 PZ |
123 | 0; |
124 | ||
125 | #undef SCHED_FEAT | |
126 | ||
127 | #ifdef CONFIG_SCHED_DEBUG | |
128 | #define SCHED_FEAT(name, enabled) \ | |
129 | #name , | |
130 | ||
1292531f | 131 | static const char * const sched_feat_names[] = { |
391e43da | 132 | #include "features.h" |
f00b45c1 PZ |
133 | }; |
134 | ||
135 | #undef SCHED_FEAT | |
136 | ||
34f3a814 | 137 | static int sched_feat_show(struct seq_file *m, void *v) |
f00b45c1 | 138 | { |
f00b45c1 PZ |
139 | int i; |
140 | ||
f8b6d1cc | 141 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
34f3a814 LZ |
142 | if (!(sysctl_sched_features & (1UL << i))) |
143 | seq_puts(m, "NO_"); | |
144 | seq_printf(m, "%s ", sched_feat_names[i]); | |
f00b45c1 | 145 | } |
34f3a814 | 146 | seq_puts(m, "\n"); |
f00b45c1 | 147 | |
34f3a814 | 148 | return 0; |
f00b45c1 PZ |
149 | } |
150 | ||
f8b6d1cc PZ |
151 | #ifdef HAVE_JUMP_LABEL |
152 | ||
c5905afb IM |
153 | #define jump_label_key__true STATIC_KEY_INIT_TRUE |
154 | #define jump_label_key__false STATIC_KEY_INIT_FALSE | |
f8b6d1cc PZ |
155 | |
156 | #define SCHED_FEAT(name, enabled) \ | |
157 | jump_label_key__##enabled , | |
158 | ||
c5905afb | 159 | struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { |
f8b6d1cc PZ |
160 | #include "features.h" |
161 | }; | |
162 | ||
163 | #undef SCHED_FEAT | |
164 | ||
165 | static void sched_feat_disable(int i) | |
166 | { | |
e33886b3 | 167 | static_key_disable(&sched_feat_keys[i]); |
f8b6d1cc PZ |
168 | } |
169 | ||
170 | static void sched_feat_enable(int i) | |
171 | { | |
e33886b3 | 172 | static_key_enable(&sched_feat_keys[i]); |
f8b6d1cc PZ |
173 | } |
174 | #else | |
175 | static void sched_feat_disable(int i) { }; | |
176 | static void sched_feat_enable(int i) { }; | |
177 | #endif /* HAVE_JUMP_LABEL */ | |
178 | ||
1a687c2e | 179 | static int sched_feat_set(char *cmp) |
f00b45c1 | 180 | { |
f00b45c1 | 181 | int i; |
1a687c2e | 182 | int neg = 0; |
f00b45c1 | 183 | |
524429c3 | 184 | if (strncmp(cmp, "NO_", 3) == 0) { |
f00b45c1 PZ |
185 | neg = 1; |
186 | cmp += 3; | |
187 | } | |
188 | ||
f8b6d1cc | 189 | for (i = 0; i < __SCHED_FEAT_NR; i++) { |
7740191c | 190 | if (strcmp(cmp, sched_feat_names[i]) == 0) { |
f8b6d1cc | 191 | if (neg) { |
f00b45c1 | 192 | sysctl_sched_features &= ~(1UL << i); |
f8b6d1cc PZ |
193 | sched_feat_disable(i); |
194 | } else { | |
f00b45c1 | 195 | sysctl_sched_features |= (1UL << i); |
f8b6d1cc PZ |
196 | sched_feat_enable(i); |
197 | } | |
f00b45c1 PZ |
198 | break; |
199 | } | |
200 | } | |
201 | ||
1a687c2e MG |
202 | return i; |
203 | } | |
204 | ||
205 | static ssize_t | |
206 | sched_feat_write(struct file *filp, const char __user *ubuf, | |
207 | size_t cnt, loff_t *ppos) | |
208 | { | |
209 | char buf[64]; | |
210 | char *cmp; | |
211 | int i; | |
5cd08fbf | 212 | struct inode *inode; |
1a687c2e MG |
213 | |
214 | if (cnt > 63) | |
215 | cnt = 63; | |
216 | ||
217 | if (copy_from_user(&buf, ubuf, cnt)) | |
218 | return -EFAULT; | |
219 | ||
220 | buf[cnt] = 0; | |
221 | cmp = strstrip(buf); | |
222 | ||
5cd08fbf JB |
223 | /* Ensure the static_key remains in a consistent state */ |
224 | inode = file_inode(filp); | |
5955102c | 225 | inode_lock(inode); |
1a687c2e | 226 | i = sched_feat_set(cmp); |
5955102c | 227 | inode_unlock(inode); |
f8b6d1cc | 228 | if (i == __SCHED_FEAT_NR) |
f00b45c1 PZ |
229 | return -EINVAL; |
230 | ||
42994724 | 231 | *ppos += cnt; |
f00b45c1 PZ |
232 | |
233 | return cnt; | |
234 | } | |
235 | ||
34f3a814 LZ |
236 | static int sched_feat_open(struct inode *inode, struct file *filp) |
237 | { | |
238 | return single_open(filp, sched_feat_show, NULL); | |
239 | } | |
240 | ||
828c0950 | 241 | static const struct file_operations sched_feat_fops = { |
34f3a814 LZ |
242 | .open = sched_feat_open, |
243 | .write = sched_feat_write, | |
244 | .read = seq_read, | |
245 | .llseek = seq_lseek, | |
246 | .release = single_release, | |
f00b45c1 PZ |
247 | }; |
248 | ||
249 | static __init int sched_init_debug(void) | |
250 | { | |
f00b45c1 PZ |
251 | debugfs_create_file("sched_features", 0644, NULL, NULL, |
252 | &sched_feat_fops); | |
253 | ||
254 | return 0; | |
255 | } | |
256 | late_initcall(sched_init_debug); | |
f8b6d1cc | 257 | #endif /* CONFIG_SCHED_DEBUG */ |
bf5c91ba | 258 | |
b82d9fdd PZ |
259 | /* |
260 | * Number of tasks to iterate in a single balance run. | |
261 | * Limited because this is done with IRQs disabled. | |
262 | */ | |
263 | const_debug unsigned int sysctl_sched_nr_migrate = 32; | |
264 | ||
e9e9250b PZ |
265 | /* |
266 | * period over which we average the RT time consumption, measured | |
267 | * in ms. | |
268 | * | |
269 | * default: 1s | |
270 | */ | |
271 | const_debug unsigned int sysctl_sched_time_avg = MSEC_PER_SEC; | |
272 | ||
fa85ae24 | 273 | /* |
9f0c1e56 | 274 | * period over which we measure -rt task cpu usage in us. |
fa85ae24 PZ |
275 | * default: 1s |
276 | */ | |
9f0c1e56 | 277 | unsigned int sysctl_sched_rt_period = 1000000; |
fa85ae24 | 278 | |
029632fb | 279 | __read_mostly int scheduler_running; |
6892b75e | 280 | |
9f0c1e56 PZ |
281 | /* |
282 | * part of the period that we allow rt tasks to run in us. | |
283 | * default: 0.95s | |
284 | */ | |
285 | int sysctl_sched_rt_runtime = 950000; | |
fa85ae24 | 286 | |
3fa0818b RR |
287 | /* cpus with isolated domains */ |
288 | cpumask_var_t cpu_isolated_map; | |
289 | ||
1da177e4 | 290 | /* |
cc2a73b5 | 291 | * this_rq_lock - lock this runqueue and disable interrupts. |
1da177e4 | 292 | */ |
a9957449 | 293 | static struct rq *this_rq_lock(void) |
1da177e4 LT |
294 | __acquires(rq->lock) |
295 | { | |
70b97a7f | 296 | struct rq *rq; |
1da177e4 LT |
297 | |
298 | local_irq_disable(); | |
299 | rq = this_rq(); | |
05fa785c | 300 | raw_spin_lock(&rq->lock); |
1da177e4 LT |
301 | |
302 | return rq; | |
303 | } | |
304 | ||
8f4d37ec PZ |
305 | #ifdef CONFIG_SCHED_HRTICK |
306 | /* | |
307 | * Use HR-timers to deliver accurate preemption points. | |
8f4d37ec | 308 | */ |
8f4d37ec | 309 | |
8f4d37ec PZ |
310 | static void hrtick_clear(struct rq *rq) |
311 | { | |
312 | if (hrtimer_active(&rq->hrtick_timer)) | |
313 | hrtimer_cancel(&rq->hrtick_timer); | |
314 | } | |
315 | ||
8f4d37ec PZ |
316 | /* |
317 | * High-resolution timer tick. | |
318 | * Runs from hardirq context with interrupts disabled. | |
319 | */ | |
320 | static enum hrtimer_restart hrtick(struct hrtimer *timer) | |
321 | { | |
322 | struct rq *rq = container_of(timer, struct rq, hrtick_timer); | |
323 | ||
324 | WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); | |
325 | ||
05fa785c | 326 | raw_spin_lock(&rq->lock); |
3e51f33f | 327 | update_rq_clock(rq); |
8f4d37ec | 328 | rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
05fa785c | 329 | raw_spin_unlock(&rq->lock); |
8f4d37ec PZ |
330 | |
331 | return HRTIMER_NORESTART; | |
332 | } | |
333 | ||
95e904c7 | 334 | #ifdef CONFIG_SMP |
971ee28c | 335 | |
4961b6e1 | 336 | static void __hrtick_restart(struct rq *rq) |
971ee28c PZ |
337 | { |
338 | struct hrtimer *timer = &rq->hrtick_timer; | |
971ee28c | 339 | |
4961b6e1 | 340 | hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED); |
971ee28c PZ |
341 | } |
342 | ||
31656519 PZ |
343 | /* |
344 | * called from hardirq (IPI) context | |
345 | */ | |
346 | static void __hrtick_start(void *arg) | |
b328ca18 | 347 | { |
31656519 | 348 | struct rq *rq = arg; |
b328ca18 | 349 | |
05fa785c | 350 | raw_spin_lock(&rq->lock); |
971ee28c | 351 | __hrtick_restart(rq); |
31656519 | 352 | rq->hrtick_csd_pending = 0; |
05fa785c | 353 | raw_spin_unlock(&rq->lock); |
b328ca18 PZ |
354 | } |
355 | ||
31656519 PZ |
356 | /* |
357 | * Called to set the hrtick timer state. | |
358 | * | |
359 | * called with rq->lock held and irqs disabled | |
360 | */ | |
029632fb | 361 | void hrtick_start(struct rq *rq, u64 delay) |
b328ca18 | 362 | { |
31656519 | 363 | struct hrtimer *timer = &rq->hrtick_timer; |
177ef2a6 | 364 | ktime_t time; |
365 | s64 delta; | |
366 | ||
367 | /* | |
368 | * Don't schedule slices shorter than 10000ns, that just | |
369 | * doesn't make sense and can cause timer DoS. | |
370 | */ | |
371 | delta = max_t(s64, delay, 10000LL); | |
372 | time = ktime_add_ns(timer->base->get_time(), delta); | |
b328ca18 | 373 | |
cc584b21 | 374 | hrtimer_set_expires(timer, time); |
31656519 PZ |
375 | |
376 | if (rq == this_rq()) { | |
971ee28c | 377 | __hrtick_restart(rq); |
31656519 | 378 | } else if (!rq->hrtick_csd_pending) { |
c46fff2a | 379 | smp_call_function_single_async(cpu_of(rq), &rq->hrtick_csd); |
31656519 PZ |
380 | rq->hrtick_csd_pending = 1; |
381 | } | |
b328ca18 PZ |
382 | } |
383 | ||
384 | static int | |
385 | hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) | |
386 | { | |
387 | int cpu = (int)(long)hcpu; | |
388 | ||
389 | switch (action) { | |
390 | case CPU_UP_CANCELED: | |
391 | case CPU_UP_CANCELED_FROZEN: | |
392 | case CPU_DOWN_PREPARE: | |
393 | case CPU_DOWN_PREPARE_FROZEN: | |
394 | case CPU_DEAD: | |
395 | case CPU_DEAD_FROZEN: | |
31656519 | 396 | hrtick_clear(cpu_rq(cpu)); |
b328ca18 PZ |
397 | return NOTIFY_OK; |
398 | } | |
399 | ||
400 | return NOTIFY_DONE; | |
401 | } | |
402 | ||
fa748203 | 403 | static __init void init_hrtick(void) |
b328ca18 PZ |
404 | { |
405 | hotcpu_notifier(hotplug_hrtick, 0); | |
406 | } | |
31656519 PZ |
407 | #else |
408 | /* | |
409 | * Called to set the hrtick timer state. | |
410 | * | |
411 | * called with rq->lock held and irqs disabled | |
412 | */ | |
029632fb | 413 | void hrtick_start(struct rq *rq, u64 delay) |
31656519 | 414 | { |
86893335 WL |
415 | /* |
416 | * Don't schedule slices shorter than 10000ns, that just | |
417 | * doesn't make sense. Rely on vruntime for fairness. | |
418 | */ | |
419 | delay = max_t(u64, delay, 10000LL); | |
4961b6e1 TG |
420 | hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), |
421 | HRTIMER_MODE_REL_PINNED); | |
31656519 | 422 | } |
b328ca18 | 423 | |
006c75f1 | 424 | static inline void init_hrtick(void) |
8f4d37ec | 425 | { |
8f4d37ec | 426 | } |
31656519 | 427 | #endif /* CONFIG_SMP */ |
8f4d37ec | 428 | |
31656519 | 429 | static void init_rq_hrtick(struct rq *rq) |
8f4d37ec | 430 | { |
31656519 PZ |
431 | #ifdef CONFIG_SMP |
432 | rq->hrtick_csd_pending = 0; | |
8f4d37ec | 433 | |
31656519 PZ |
434 | rq->hrtick_csd.flags = 0; |
435 | rq->hrtick_csd.func = __hrtick_start; | |
436 | rq->hrtick_csd.info = rq; | |
437 | #endif | |
8f4d37ec | 438 | |
31656519 PZ |
439 | hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
440 | rq->hrtick_timer.function = hrtick; | |
8f4d37ec | 441 | } |
006c75f1 | 442 | #else /* CONFIG_SCHED_HRTICK */ |
8f4d37ec PZ |
443 | static inline void hrtick_clear(struct rq *rq) |
444 | { | |
445 | } | |
446 | ||
8f4d37ec PZ |
447 | static inline void init_rq_hrtick(struct rq *rq) |
448 | { | |
449 | } | |
450 | ||
b328ca18 PZ |
451 | static inline void init_hrtick(void) |
452 | { | |
453 | } | |
006c75f1 | 454 | #endif /* CONFIG_SCHED_HRTICK */ |
8f4d37ec | 455 | |
fd99f91a PZ |
456 | /* |
457 | * cmpxchg based fetch_or, macro so it works for different integer types | |
458 | */ | |
459 | #define fetch_or(ptr, val) \ | |
460 | ({ typeof(*(ptr)) __old, __val = *(ptr); \ | |
461 | for (;;) { \ | |
462 | __old = cmpxchg((ptr), __val, __val | (val)); \ | |
463 | if (__old == __val) \ | |
464 | break; \ | |
465 | __val = __old; \ | |
466 | } \ | |
467 | __old; \ | |
468 | }) | |
469 | ||
e3baac47 | 470 | #if defined(CONFIG_SMP) && defined(TIF_POLLING_NRFLAG) |
fd99f91a PZ |
471 | /* |
472 | * Atomically set TIF_NEED_RESCHED and test for TIF_POLLING_NRFLAG, | |
473 | * this avoids any races wrt polling state changes and thereby avoids | |
474 | * spurious IPIs. | |
475 | */ | |
476 | static bool set_nr_and_not_polling(struct task_struct *p) | |
477 | { | |
478 | struct thread_info *ti = task_thread_info(p); | |
479 | return !(fetch_or(&ti->flags, _TIF_NEED_RESCHED) & _TIF_POLLING_NRFLAG); | |
480 | } | |
e3baac47 PZ |
481 | |
482 | /* | |
483 | * Atomically set TIF_NEED_RESCHED if TIF_POLLING_NRFLAG is set. | |
484 | * | |
485 | * If this returns true, then the idle task promises to call | |
486 | * sched_ttwu_pending() and reschedule soon. | |
487 | */ | |
488 | static bool set_nr_if_polling(struct task_struct *p) | |
489 | { | |
490 | struct thread_info *ti = task_thread_info(p); | |
316c1608 | 491 | typeof(ti->flags) old, val = READ_ONCE(ti->flags); |
e3baac47 PZ |
492 | |
493 | for (;;) { | |
494 | if (!(val & _TIF_POLLING_NRFLAG)) | |
495 | return false; | |
496 | if (val & _TIF_NEED_RESCHED) | |
497 | return true; | |
498 | old = cmpxchg(&ti->flags, val, val | _TIF_NEED_RESCHED); | |
499 | if (old == val) | |
500 | break; | |
501 | val = old; | |
502 | } | |
503 | return true; | |
504 | } | |
505 | ||
fd99f91a PZ |
506 | #else |
507 | static bool set_nr_and_not_polling(struct task_struct *p) | |
508 | { | |
509 | set_tsk_need_resched(p); | |
510 | return true; | |
511 | } | |
e3baac47 PZ |
512 | |
513 | #ifdef CONFIG_SMP | |
514 | static bool set_nr_if_polling(struct task_struct *p) | |
515 | { | |
516 | return false; | |
517 | } | |
518 | #endif | |
fd99f91a PZ |
519 | #endif |
520 | ||
76751049 PZ |
521 | void wake_q_add(struct wake_q_head *head, struct task_struct *task) |
522 | { | |
523 | struct wake_q_node *node = &task->wake_q; | |
524 | ||
525 | /* | |
526 | * Atomically grab the task, if ->wake_q is !nil already it means | |
527 | * its already queued (either by us or someone else) and will get the | |
528 | * wakeup due to that. | |
529 | * | |
530 | * This cmpxchg() implies a full barrier, which pairs with the write | |
531 | * barrier implied by the wakeup in wake_up_list(). | |
532 | */ | |
533 | if (cmpxchg(&node->next, NULL, WAKE_Q_TAIL)) | |
534 | return; | |
535 | ||
536 | get_task_struct(task); | |
537 | ||
538 | /* | |
539 | * The head is context local, there can be no concurrency. | |
540 | */ | |
541 | *head->lastp = node; | |
542 | head->lastp = &node->next; | |
543 | } | |
544 | ||
545 | void wake_up_q(struct wake_q_head *head) | |
546 | { | |
547 | struct wake_q_node *node = head->first; | |
548 | ||
549 | while (node != WAKE_Q_TAIL) { | |
550 | struct task_struct *task; | |
551 | ||
552 | task = container_of(node, struct task_struct, wake_q); | |
553 | BUG_ON(!task); | |
554 | /* task can safely be re-inserted now */ | |
555 | node = node->next; | |
556 | task->wake_q.next = NULL; | |
557 | ||
558 | /* | |
559 | * wake_up_process() implies a wmb() to pair with the queueing | |
560 | * in wake_q_add() so as not to miss wakeups. | |
561 | */ | |
562 | wake_up_process(task); | |
563 | put_task_struct(task); | |
564 | } | |
565 | } | |
566 | ||
c24d20db | 567 | /* |
8875125e | 568 | * resched_curr - mark rq's current task 'to be rescheduled now'. |
c24d20db IM |
569 | * |
570 | * On UP this means the setting of the need_resched flag, on SMP it | |
571 | * might also involve a cross-CPU call to trigger the scheduler on | |
572 | * the target CPU. | |
573 | */ | |
8875125e | 574 | void resched_curr(struct rq *rq) |
c24d20db | 575 | { |
8875125e | 576 | struct task_struct *curr = rq->curr; |
c24d20db IM |
577 | int cpu; |
578 | ||
8875125e | 579 | lockdep_assert_held(&rq->lock); |
c24d20db | 580 | |
8875125e | 581 | if (test_tsk_need_resched(curr)) |
c24d20db IM |
582 | return; |
583 | ||
8875125e | 584 | cpu = cpu_of(rq); |
fd99f91a | 585 | |
f27dde8d | 586 | if (cpu == smp_processor_id()) { |
8875125e | 587 | set_tsk_need_resched(curr); |
f27dde8d | 588 | set_preempt_need_resched(); |
c24d20db | 589 | return; |
f27dde8d | 590 | } |
c24d20db | 591 | |
8875125e | 592 | if (set_nr_and_not_polling(curr)) |
c24d20db | 593 | smp_send_reschedule(cpu); |
dfc68f29 AL |
594 | else |
595 | trace_sched_wake_idle_without_ipi(cpu); | |
c24d20db IM |
596 | } |
597 | ||
029632fb | 598 | void resched_cpu(int cpu) |
c24d20db IM |
599 | { |
600 | struct rq *rq = cpu_rq(cpu); | |
601 | unsigned long flags; | |
602 | ||
05fa785c | 603 | if (!raw_spin_trylock_irqsave(&rq->lock, flags)) |
c24d20db | 604 | return; |
8875125e | 605 | resched_curr(rq); |
05fa785c | 606 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
c24d20db | 607 | } |
06d8308c | 608 | |
b021fe3e | 609 | #ifdef CONFIG_SMP |
3451d024 | 610 | #ifdef CONFIG_NO_HZ_COMMON |
83cd4fe2 VP |
611 | /* |
612 | * In the semi idle case, use the nearest busy cpu for migrating timers | |
613 | * from an idle cpu. This is good for power-savings. | |
614 | * | |
615 | * We don't do similar optimization for completely idle system, as | |
616 | * selecting an idle cpu will add more delays to the timers than intended | |
617 | * (as that cpu's timer base may not be uptodate wrt jiffies etc). | |
618 | */ | |
bc7a34b8 | 619 | int get_nohz_timer_target(void) |
83cd4fe2 | 620 | { |
bc7a34b8 | 621 | int i, cpu = smp_processor_id(); |
83cd4fe2 VP |
622 | struct sched_domain *sd; |
623 | ||
9642d18e | 624 | if (!idle_cpu(cpu) && is_housekeeping_cpu(cpu)) |
6201b4d6 VK |
625 | return cpu; |
626 | ||
057f3fad | 627 | rcu_read_lock(); |
83cd4fe2 | 628 | for_each_domain(cpu, sd) { |
057f3fad | 629 | for_each_cpu(i, sched_domain_span(sd)) { |
9642d18e | 630 | if (!idle_cpu(i) && is_housekeeping_cpu(cpu)) { |
057f3fad PZ |
631 | cpu = i; |
632 | goto unlock; | |
633 | } | |
634 | } | |
83cd4fe2 | 635 | } |
9642d18e VH |
636 | |
637 | if (!is_housekeeping_cpu(cpu)) | |
638 | cpu = housekeeping_any_cpu(); | |
057f3fad PZ |
639 | unlock: |
640 | rcu_read_unlock(); | |
83cd4fe2 VP |
641 | return cpu; |
642 | } | |
06d8308c TG |
643 | /* |
644 | * When add_timer_on() enqueues a timer into the timer wheel of an | |
645 | * idle CPU then this timer might expire before the next timer event | |
646 | * which is scheduled to wake up that CPU. In case of a completely | |
647 | * idle system the next event might even be infinite time into the | |
648 | * future. wake_up_idle_cpu() ensures that the CPU is woken up and | |
649 | * leaves the inner idle loop so the newly added timer is taken into | |
650 | * account when the CPU goes back to idle and evaluates the timer | |
651 | * wheel for the next timer event. | |
652 | */ | |
1c20091e | 653 | static void wake_up_idle_cpu(int cpu) |
06d8308c TG |
654 | { |
655 | struct rq *rq = cpu_rq(cpu); | |
656 | ||
657 | if (cpu == smp_processor_id()) | |
658 | return; | |
659 | ||
67b9ca70 | 660 | if (set_nr_and_not_polling(rq->idle)) |
06d8308c | 661 | smp_send_reschedule(cpu); |
dfc68f29 AL |
662 | else |
663 | trace_sched_wake_idle_without_ipi(cpu); | |
45bf76df IM |
664 | } |
665 | ||
c5bfece2 | 666 | static bool wake_up_full_nohz_cpu(int cpu) |
1c20091e | 667 | { |
53c5fa16 FW |
668 | /* |
669 | * We just need the target to call irq_exit() and re-evaluate | |
670 | * the next tick. The nohz full kick at least implies that. | |
671 | * If needed we can still optimize that later with an | |
672 | * empty IRQ. | |
673 | */ | |
c5bfece2 | 674 | if (tick_nohz_full_cpu(cpu)) { |
1c20091e FW |
675 | if (cpu != smp_processor_id() || |
676 | tick_nohz_tick_stopped()) | |
53c5fa16 | 677 | tick_nohz_full_kick_cpu(cpu); |
1c20091e FW |
678 | return true; |
679 | } | |
680 | ||
681 | return false; | |
682 | } | |
683 | ||
684 | void wake_up_nohz_cpu(int cpu) | |
685 | { | |
c5bfece2 | 686 | if (!wake_up_full_nohz_cpu(cpu)) |
1c20091e FW |
687 | wake_up_idle_cpu(cpu); |
688 | } | |
689 | ||
ca38062e | 690 | static inline bool got_nohz_idle_kick(void) |
45bf76df | 691 | { |
1c792db7 | 692 | int cpu = smp_processor_id(); |
873b4c65 VG |
693 | |
694 | if (!test_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu))) | |
695 | return false; | |
696 | ||
697 | if (idle_cpu(cpu) && !need_resched()) | |
698 | return true; | |
699 | ||
700 | /* | |
701 | * We can't run Idle Load Balance on this CPU for this time so we | |
702 | * cancel it and clear NOHZ_BALANCE_KICK | |
703 | */ | |
704 | clear_bit(NOHZ_BALANCE_KICK, nohz_flags(cpu)); | |
705 | return false; | |
45bf76df IM |
706 | } |
707 | ||
3451d024 | 708 | #else /* CONFIG_NO_HZ_COMMON */ |
45bf76df | 709 | |
ca38062e | 710 | static inline bool got_nohz_idle_kick(void) |
2069dd75 | 711 | { |
ca38062e | 712 | return false; |
2069dd75 PZ |
713 | } |
714 | ||
3451d024 | 715 | #endif /* CONFIG_NO_HZ_COMMON */ |
d842de87 | 716 | |
ce831b38 FW |
717 | #ifdef CONFIG_NO_HZ_FULL |
718 | bool sched_can_stop_tick(void) | |
719 | { | |
1e78cdbd RR |
720 | /* |
721 | * FIFO realtime policy runs the highest priority task. Other runnable | |
722 | * tasks are of a lower priority. The scheduler tick does nothing. | |
723 | */ | |
724 | if (current->policy == SCHED_FIFO) | |
725 | return true; | |
726 | ||
727 | /* | |
728 | * Round-robin realtime tasks time slice with other tasks at the same | |
729 | * realtime priority. Is this task the only one at this priority? | |
730 | */ | |
731 | if (current->policy == SCHED_RR) { | |
732 | struct sched_rt_entity *rt_se = ¤t->rt; | |
733 | ||
01783e0d | 734 | return list_is_singular(&rt_se->run_list); |
1e78cdbd RR |
735 | } |
736 | ||
3882ec64 FW |
737 | /* |
738 | * More than one running task need preemption. | |
739 | * nr_running update is assumed to be visible | |
740 | * after IPI is sent from wakers. | |
741 | */ | |
541b8264 VK |
742 | if (this_rq()->nr_running > 1) |
743 | return false; | |
ce831b38 | 744 | |
541b8264 | 745 | return true; |
ce831b38 FW |
746 | } |
747 | #endif /* CONFIG_NO_HZ_FULL */ | |
d842de87 | 748 | |
029632fb | 749 | void sched_avg_update(struct rq *rq) |
18d95a28 | 750 | { |
e9e9250b PZ |
751 | s64 period = sched_avg_period(); |
752 | ||
78becc27 | 753 | while ((s64)(rq_clock(rq) - rq->age_stamp) > period) { |
0d98bb26 WD |
754 | /* |
755 | * Inline assembly required to prevent the compiler | |
756 | * optimising this loop into a divmod call. | |
757 | * See __iter_div_u64_rem() for another example of this. | |
758 | */ | |
759 | asm("" : "+rm" (rq->age_stamp)); | |
e9e9250b PZ |
760 | rq->age_stamp += period; |
761 | rq->rt_avg /= 2; | |
762 | } | |
18d95a28 PZ |
763 | } |
764 | ||
6d6bc0ad | 765 | #endif /* CONFIG_SMP */ |
18d95a28 | 766 | |
a790de99 PT |
767 | #if defined(CONFIG_RT_GROUP_SCHED) || (defined(CONFIG_FAIR_GROUP_SCHED) && \ |
768 | (defined(CONFIG_SMP) || defined(CONFIG_CFS_BANDWIDTH))) | |
c09595f6 | 769 | /* |
8277434e PT |
770 | * Iterate task_group tree rooted at *from, calling @down when first entering a |
771 | * node and @up when leaving it for the final time. | |
772 | * | |
773 | * Caller must hold rcu_lock or sufficient equivalent. | |
c09595f6 | 774 | */ |
029632fb | 775 | int walk_tg_tree_from(struct task_group *from, |
8277434e | 776 | tg_visitor down, tg_visitor up, void *data) |
c09595f6 PZ |
777 | { |
778 | struct task_group *parent, *child; | |
eb755805 | 779 | int ret; |
c09595f6 | 780 | |
8277434e PT |
781 | parent = from; |
782 | ||
c09595f6 | 783 | down: |
eb755805 PZ |
784 | ret = (*down)(parent, data); |
785 | if (ret) | |
8277434e | 786 | goto out; |
c09595f6 PZ |
787 | list_for_each_entry_rcu(child, &parent->children, siblings) { |
788 | parent = child; | |
789 | goto down; | |
790 | ||
791 | up: | |
792 | continue; | |
793 | } | |
eb755805 | 794 | ret = (*up)(parent, data); |
8277434e PT |
795 | if (ret || parent == from) |
796 | goto out; | |
c09595f6 PZ |
797 | |
798 | child = parent; | |
799 | parent = parent->parent; | |
800 | if (parent) | |
801 | goto up; | |
8277434e | 802 | out: |
eb755805 | 803 | return ret; |
c09595f6 PZ |
804 | } |
805 | ||
029632fb | 806 | int tg_nop(struct task_group *tg, void *data) |
eb755805 | 807 | { |
e2b245f8 | 808 | return 0; |
eb755805 | 809 | } |
18d95a28 PZ |
810 | #endif |
811 | ||
45bf76df IM |
812 | static void set_load_weight(struct task_struct *p) |
813 | { | |
f05998d4 NR |
814 | int prio = p->static_prio - MAX_RT_PRIO; |
815 | struct load_weight *load = &p->se.load; | |
816 | ||
dd41f596 IM |
817 | /* |
818 | * SCHED_IDLE tasks get minimal weight: | |
819 | */ | |
20f9cd2a | 820 | if (idle_policy(p->policy)) { |
c8b28116 | 821 | load->weight = scale_load(WEIGHT_IDLEPRIO); |
f05998d4 | 822 | load->inv_weight = WMULT_IDLEPRIO; |
dd41f596 IM |
823 | return; |
824 | } | |
71f8bd46 | 825 | |
ed82b8a1 AK |
826 | load->weight = scale_load(sched_prio_to_weight[prio]); |
827 | load->inv_weight = sched_prio_to_wmult[prio]; | |
71f8bd46 IM |
828 | } |
829 | ||
1de64443 | 830 | static inline void enqueue_task(struct rq *rq, struct task_struct *p, int flags) |
2087a1ad | 831 | { |
a64692a3 | 832 | update_rq_clock(rq); |
1de64443 PZ |
833 | if (!(flags & ENQUEUE_RESTORE)) |
834 | sched_info_queued(rq, p); | |
371fd7e7 | 835 | p->sched_class->enqueue_task(rq, p, flags); |
71f8bd46 IM |
836 | } |
837 | ||
1de64443 | 838 | static inline void dequeue_task(struct rq *rq, struct task_struct *p, int flags) |
71f8bd46 | 839 | { |
a64692a3 | 840 | update_rq_clock(rq); |
1de64443 PZ |
841 | if (!(flags & DEQUEUE_SAVE)) |
842 | sched_info_dequeued(rq, p); | |
371fd7e7 | 843 | p->sched_class->dequeue_task(rq, p, flags); |
71f8bd46 IM |
844 | } |
845 | ||
029632fb | 846 | void activate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
847 | { |
848 | if (task_contributes_to_load(p)) | |
849 | rq->nr_uninterruptible--; | |
850 | ||
371fd7e7 | 851 | enqueue_task(rq, p, flags); |
1e3c88bd PZ |
852 | } |
853 | ||
029632fb | 854 | void deactivate_task(struct rq *rq, struct task_struct *p, int flags) |
1e3c88bd PZ |
855 | { |
856 | if (task_contributes_to_load(p)) | |
857 | rq->nr_uninterruptible++; | |
858 | ||
371fd7e7 | 859 | dequeue_task(rq, p, flags); |
1e3c88bd PZ |
860 | } |
861 | ||
fe44d621 | 862 | static void update_rq_clock_task(struct rq *rq, s64 delta) |
aa483808 | 863 | { |
095c0aa8 GC |
864 | /* |
865 | * In theory, the compile should just see 0 here, and optimize out the call | |
866 | * to sched_rt_avg_update. But I don't trust it... | |
867 | */ | |
868 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) | |
869 | s64 steal = 0, irq_delta = 0; | |
870 | #endif | |
871 | #ifdef CONFIG_IRQ_TIME_ACCOUNTING | |
8e92c201 | 872 | irq_delta = irq_time_read(cpu_of(rq)) - rq->prev_irq_time; |
fe44d621 PZ |
873 | |
874 | /* | |
875 | * Since irq_time is only updated on {soft,}irq_exit, we might run into | |
876 | * this case when a previous update_rq_clock() happened inside a | |
877 | * {soft,}irq region. | |
878 | * | |
879 | * When this happens, we stop ->clock_task and only update the | |
880 | * prev_irq_time stamp to account for the part that fit, so that a next | |
881 | * update will consume the rest. This ensures ->clock_task is | |
882 | * monotonic. | |
883 | * | |
884 | * It does however cause some slight miss-attribution of {soft,}irq | |
885 | * time, a more accurate solution would be to update the irq_time using | |
886 | * the current rq->clock timestamp, except that would require using | |
887 | * atomic ops. | |
888 | */ | |
889 | if (irq_delta > delta) | |
890 | irq_delta = delta; | |
891 | ||
892 | rq->prev_irq_time += irq_delta; | |
893 | delta -= irq_delta; | |
095c0aa8 GC |
894 | #endif |
895 | #ifdef CONFIG_PARAVIRT_TIME_ACCOUNTING | |
c5905afb | 896 | if (static_key_false((¶virt_steal_rq_enabled))) { |
095c0aa8 GC |
897 | steal = paravirt_steal_clock(cpu_of(rq)); |
898 | steal -= rq->prev_steal_time_rq; | |
899 | ||
900 | if (unlikely(steal > delta)) | |
901 | steal = delta; | |
902 | ||
095c0aa8 | 903 | rq->prev_steal_time_rq += steal; |
095c0aa8 GC |
904 | delta -= steal; |
905 | } | |
906 | #endif | |
907 | ||
fe44d621 PZ |
908 | rq->clock_task += delta; |
909 | ||
095c0aa8 | 910 | #if defined(CONFIG_IRQ_TIME_ACCOUNTING) || defined(CONFIG_PARAVIRT_TIME_ACCOUNTING) |
5d4dfddd | 911 | if ((irq_delta + steal) && sched_feat(NONTASK_CAPACITY)) |
095c0aa8 GC |
912 | sched_rt_avg_update(rq, irq_delta + steal); |
913 | #endif | |
aa483808 VP |
914 | } |
915 | ||
34f971f6 PZ |
916 | void sched_set_stop_task(int cpu, struct task_struct *stop) |
917 | { | |
918 | struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 }; | |
919 | struct task_struct *old_stop = cpu_rq(cpu)->stop; | |
920 | ||
921 | if (stop) { | |
922 | /* | |
923 | * Make it appear like a SCHED_FIFO task, its something | |
924 | * userspace knows about and won't get confused about. | |
925 | * | |
926 | * Also, it will make PI more or less work without too | |
927 | * much confusion -- but then, stop work should not | |
928 | * rely on PI working anyway. | |
929 | */ | |
930 | sched_setscheduler_nocheck(stop, SCHED_FIFO, ¶m); | |
931 | ||
932 | stop->sched_class = &stop_sched_class; | |
933 | } | |
934 | ||
935 | cpu_rq(cpu)->stop = stop; | |
936 | ||
937 | if (old_stop) { | |
938 | /* | |
939 | * Reset it back to a normal scheduling class so that | |
940 | * it can die in pieces. | |
941 | */ | |
942 | old_stop->sched_class = &rt_sched_class; | |
943 | } | |
944 | } | |
945 | ||
14531189 | 946 | /* |
dd41f596 | 947 | * __normal_prio - return the priority that is based on the static prio |
14531189 | 948 | */ |
14531189 IM |
949 | static inline int __normal_prio(struct task_struct *p) |
950 | { | |
dd41f596 | 951 | return p->static_prio; |
14531189 IM |
952 | } |
953 | ||
b29739f9 IM |
954 | /* |
955 | * Calculate the expected normal priority: i.e. priority | |
956 | * without taking RT-inheritance into account. Might be | |
957 | * boosted by interactivity modifiers. Changes upon fork, | |
958 | * setprio syscalls, and whenever the interactivity | |
959 | * estimator recalculates. | |
960 | */ | |
36c8b586 | 961 | static inline int normal_prio(struct task_struct *p) |
b29739f9 IM |
962 | { |
963 | int prio; | |
964 | ||
aab03e05 DF |
965 | if (task_has_dl_policy(p)) |
966 | prio = MAX_DL_PRIO-1; | |
967 | else if (task_has_rt_policy(p)) | |
b29739f9 IM |
968 | prio = MAX_RT_PRIO-1 - p->rt_priority; |
969 | else | |
970 | prio = __normal_prio(p); | |
971 | return prio; | |
972 | } | |
973 | ||
974 | /* | |
975 | * Calculate the current priority, i.e. the priority | |
976 | * taken into account by the scheduler. This value might | |
977 | * be boosted by RT tasks, or might be boosted by | |
978 | * interactivity modifiers. Will be RT if the task got | |
979 | * RT-boosted. If not then it returns p->normal_prio. | |
980 | */ | |
36c8b586 | 981 | static int effective_prio(struct task_struct *p) |
b29739f9 IM |
982 | { |
983 | p->normal_prio = normal_prio(p); | |
984 | /* | |
985 | * If we are RT tasks or we were boosted to RT priority, | |
986 | * keep the priority unchanged. Otherwise, update priority | |
987 | * to the normal priority: | |
988 | */ | |
989 | if (!rt_prio(p->prio)) | |
990 | return p->normal_prio; | |
991 | return p->prio; | |
992 | } | |
993 | ||
1da177e4 LT |
994 | /** |
995 | * task_curr - is this task currently executing on a CPU? | |
996 | * @p: the task in question. | |
e69f6186 YB |
997 | * |
998 | * Return: 1 if the task is currently executing. 0 otherwise. | |
1da177e4 | 999 | */ |
36c8b586 | 1000 | inline int task_curr(const struct task_struct *p) |
1da177e4 LT |
1001 | { |
1002 | return cpu_curr(task_cpu(p)) == p; | |
1003 | } | |
1004 | ||
67dfa1b7 | 1005 | /* |
4c9a4bc8 PZ |
1006 | * switched_from, switched_to and prio_changed must _NOT_ drop rq->lock, |
1007 | * use the balance_callback list if you want balancing. | |
1008 | * | |
1009 | * this means any call to check_class_changed() must be followed by a call to | |
1010 | * balance_callback(). | |
67dfa1b7 | 1011 | */ |
cb469845 SR |
1012 | static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
1013 | const struct sched_class *prev_class, | |
da7a735e | 1014 | int oldprio) |
cb469845 SR |
1015 | { |
1016 | if (prev_class != p->sched_class) { | |
1017 | if (prev_class->switched_from) | |
da7a735e | 1018 | prev_class->switched_from(rq, p); |
4c9a4bc8 | 1019 | |
da7a735e | 1020 | p->sched_class->switched_to(rq, p); |
2d3d891d | 1021 | } else if (oldprio != p->prio || dl_task(p)) |
da7a735e | 1022 | p->sched_class->prio_changed(rq, p, oldprio); |
cb469845 SR |
1023 | } |
1024 | ||
029632fb | 1025 | void check_preempt_curr(struct rq *rq, struct task_struct *p, int flags) |
1e5a7405 PZ |
1026 | { |
1027 | const struct sched_class *class; | |
1028 | ||
1029 | if (p->sched_class == rq->curr->sched_class) { | |
1030 | rq->curr->sched_class->check_preempt_curr(rq, p, flags); | |
1031 | } else { | |
1032 | for_each_class(class) { | |
1033 | if (class == rq->curr->sched_class) | |
1034 | break; | |
1035 | if (class == p->sched_class) { | |
8875125e | 1036 | resched_curr(rq); |
1e5a7405 PZ |
1037 | break; |
1038 | } | |
1039 | } | |
1040 | } | |
1041 | ||
1042 | /* | |
1043 | * A queue event has occurred, and we're going to schedule. In | |
1044 | * this case, we can save a useless back to back clock update. | |
1045 | */ | |
da0c1e65 | 1046 | if (task_on_rq_queued(rq->curr) && test_tsk_need_resched(rq->curr)) |
9edfbfed | 1047 | rq_clock_skip_update(rq, true); |
1e5a7405 PZ |
1048 | } |
1049 | ||
1da177e4 | 1050 | #ifdef CONFIG_SMP |
5cc389bc PZ |
1051 | /* |
1052 | * This is how migration works: | |
1053 | * | |
1054 | * 1) we invoke migration_cpu_stop() on the target CPU using | |
1055 | * stop_one_cpu(). | |
1056 | * 2) stopper starts to run (implicitly forcing the migrated thread | |
1057 | * off the CPU) | |
1058 | * 3) it checks whether the migrated task is still in the wrong runqueue. | |
1059 | * 4) if it's in the wrong runqueue then the migration thread removes | |
1060 | * it and puts it into the right queue. | |
1061 | * 5) stopper completes and stop_one_cpu() returns and the migration | |
1062 | * is done. | |
1063 | */ | |
1064 | ||
1065 | /* | |
1066 | * move_queued_task - move a queued task to new rq. | |
1067 | * | |
1068 | * Returns (locked) new rq. Old rq's lock is released. | |
1069 | */ | |
5e16bbc2 | 1070 | static struct rq *move_queued_task(struct rq *rq, struct task_struct *p, int new_cpu) |
5cc389bc | 1071 | { |
5cc389bc PZ |
1072 | lockdep_assert_held(&rq->lock); |
1073 | ||
5cc389bc | 1074 | p->on_rq = TASK_ON_RQ_MIGRATING; |
3ea94de1 | 1075 | dequeue_task(rq, p, 0); |
5cc389bc PZ |
1076 | set_task_cpu(p, new_cpu); |
1077 | raw_spin_unlock(&rq->lock); | |
1078 | ||
1079 | rq = cpu_rq(new_cpu); | |
1080 | ||
1081 | raw_spin_lock(&rq->lock); | |
1082 | BUG_ON(task_cpu(p) != new_cpu); | |
5cc389bc | 1083 | enqueue_task(rq, p, 0); |
3ea94de1 | 1084 | p->on_rq = TASK_ON_RQ_QUEUED; |
5cc389bc PZ |
1085 | check_preempt_curr(rq, p, 0); |
1086 | ||
1087 | return rq; | |
1088 | } | |
1089 | ||
1090 | struct migration_arg { | |
1091 | struct task_struct *task; | |
1092 | int dest_cpu; | |
1093 | }; | |
1094 | ||
1095 | /* | |
1096 | * Move (not current) task off this cpu, onto dest cpu. We're doing | |
1097 | * this because either it can't run here any more (set_cpus_allowed() | |
1098 | * away from this CPU, or CPU going down), or because we're | |
1099 | * attempting to rebalance this task on exec (sched_exec). | |
1100 | * | |
1101 | * So we race with normal scheduler movements, but that's OK, as long | |
1102 | * as the task is no longer on this CPU. | |
5cc389bc | 1103 | */ |
5e16bbc2 | 1104 | static struct rq *__migrate_task(struct rq *rq, struct task_struct *p, int dest_cpu) |
5cc389bc | 1105 | { |
5cc389bc | 1106 | if (unlikely(!cpu_active(dest_cpu))) |
5e16bbc2 | 1107 | return rq; |
5cc389bc PZ |
1108 | |
1109 | /* Affinity changed (again). */ | |
1110 | if (!cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) | |
5e16bbc2 | 1111 | return rq; |
5cc389bc | 1112 | |
5e16bbc2 PZ |
1113 | rq = move_queued_task(rq, p, dest_cpu); |
1114 | ||
1115 | return rq; | |
5cc389bc PZ |
1116 | } |
1117 | ||
1118 | /* | |
1119 | * migration_cpu_stop - this will be executed by a highprio stopper thread | |
1120 | * and performs thread migration by bumping thread off CPU then | |
1121 | * 'pushing' onto another runqueue. | |
1122 | */ | |
1123 | static int migration_cpu_stop(void *data) | |
1124 | { | |
1125 | struct migration_arg *arg = data; | |
5e16bbc2 PZ |
1126 | struct task_struct *p = arg->task; |
1127 | struct rq *rq = this_rq(); | |
5cc389bc PZ |
1128 | |
1129 | /* | |
1130 | * The original target cpu might have gone down and we might | |
1131 | * be on another cpu but it doesn't matter. | |
1132 | */ | |
1133 | local_irq_disable(); | |
1134 | /* | |
1135 | * We need to explicitly wake pending tasks before running | |
1136 | * __migrate_task() such that we will not miss enforcing cpus_allowed | |
1137 | * during wakeups, see set_cpus_allowed_ptr()'s TASK_WAKING test. | |
1138 | */ | |
1139 | sched_ttwu_pending(); | |
5e16bbc2 PZ |
1140 | |
1141 | raw_spin_lock(&p->pi_lock); | |
1142 | raw_spin_lock(&rq->lock); | |
1143 | /* | |
1144 | * If task_rq(p) != rq, it cannot be migrated here, because we're | |
1145 | * holding rq->lock, if p->on_rq == 0 it cannot get enqueued because | |
1146 | * we're holding p->pi_lock. | |
1147 | */ | |
1148 | if (task_rq(p) == rq && task_on_rq_queued(p)) | |
1149 | rq = __migrate_task(rq, p, arg->dest_cpu); | |
1150 | raw_spin_unlock(&rq->lock); | |
1151 | raw_spin_unlock(&p->pi_lock); | |
1152 | ||
5cc389bc PZ |
1153 | local_irq_enable(); |
1154 | return 0; | |
1155 | } | |
1156 | ||
c5b28038 PZ |
1157 | /* |
1158 | * sched_class::set_cpus_allowed must do the below, but is not required to | |
1159 | * actually call this function. | |
1160 | */ | |
1161 | void set_cpus_allowed_common(struct task_struct *p, const struct cpumask *new_mask) | |
5cc389bc | 1162 | { |
5cc389bc PZ |
1163 | cpumask_copy(&p->cpus_allowed, new_mask); |
1164 | p->nr_cpus_allowed = cpumask_weight(new_mask); | |
1165 | } | |
1166 | ||
c5b28038 PZ |
1167 | void do_set_cpus_allowed(struct task_struct *p, const struct cpumask *new_mask) |
1168 | { | |
6c37067e PZ |
1169 | struct rq *rq = task_rq(p); |
1170 | bool queued, running; | |
1171 | ||
c5b28038 | 1172 | lockdep_assert_held(&p->pi_lock); |
6c37067e PZ |
1173 | |
1174 | queued = task_on_rq_queued(p); | |
1175 | running = task_current(rq, p); | |
1176 | ||
1177 | if (queued) { | |
1178 | /* | |
1179 | * Because __kthread_bind() calls this on blocked tasks without | |
1180 | * holding rq->lock. | |
1181 | */ | |
1182 | lockdep_assert_held(&rq->lock); | |
1de64443 | 1183 | dequeue_task(rq, p, DEQUEUE_SAVE); |
6c37067e PZ |
1184 | } |
1185 | if (running) | |
1186 | put_prev_task(rq, p); | |
1187 | ||
c5b28038 | 1188 | p->sched_class->set_cpus_allowed(p, new_mask); |
6c37067e PZ |
1189 | |
1190 | if (running) | |
1191 | p->sched_class->set_curr_task(rq); | |
1192 | if (queued) | |
1de64443 | 1193 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
c5b28038 PZ |
1194 | } |
1195 | ||
5cc389bc PZ |
1196 | /* |
1197 | * Change a given task's CPU affinity. Migrate the thread to a | |
1198 | * proper CPU and schedule it away if the CPU it's executing on | |
1199 | * is removed from the allowed bitmask. | |
1200 | * | |
1201 | * NOTE: the caller must have a valid reference to the task, the | |
1202 | * task must not exit() & deallocate itself prematurely. The | |
1203 | * call is not atomic; no spinlocks may be held. | |
1204 | */ | |
25834c73 PZ |
1205 | static int __set_cpus_allowed_ptr(struct task_struct *p, |
1206 | const struct cpumask *new_mask, bool check) | |
5cc389bc PZ |
1207 | { |
1208 | unsigned long flags; | |
1209 | struct rq *rq; | |
1210 | unsigned int dest_cpu; | |
1211 | int ret = 0; | |
1212 | ||
1213 | rq = task_rq_lock(p, &flags); | |
1214 | ||
25834c73 PZ |
1215 | /* |
1216 | * Must re-check here, to close a race against __kthread_bind(), | |
1217 | * sched_setaffinity() is not guaranteed to observe the flag. | |
1218 | */ | |
1219 | if (check && (p->flags & PF_NO_SETAFFINITY)) { | |
1220 | ret = -EINVAL; | |
1221 | goto out; | |
1222 | } | |
1223 | ||
5cc389bc PZ |
1224 | if (cpumask_equal(&p->cpus_allowed, new_mask)) |
1225 | goto out; | |
1226 | ||
1227 | if (!cpumask_intersects(new_mask, cpu_active_mask)) { | |
1228 | ret = -EINVAL; | |
1229 | goto out; | |
1230 | } | |
1231 | ||
1232 | do_set_cpus_allowed(p, new_mask); | |
1233 | ||
1234 | /* Can the task run on the task's current CPU? If so, we're done */ | |
1235 | if (cpumask_test_cpu(task_cpu(p), new_mask)) | |
1236 | goto out; | |
1237 | ||
1238 | dest_cpu = cpumask_any_and(cpu_active_mask, new_mask); | |
1239 | if (task_running(rq, p) || p->state == TASK_WAKING) { | |
1240 | struct migration_arg arg = { p, dest_cpu }; | |
1241 | /* Need help from migration thread: drop lock and wait. */ | |
1242 | task_rq_unlock(rq, p, &flags); | |
1243 | stop_one_cpu(cpu_of(rq), migration_cpu_stop, &arg); | |
1244 | tlb_migrate_finish(p->mm); | |
1245 | return 0; | |
cbce1a68 PZ |
1246 | } else if (task_on_rq_queued(p)) { |
1247 | /* | |
1248 | * OK, since we're going to drop the lock immediately | |
1249 | * afterwards anyway. | |
1250 | */ | |
1251 | lockdep_unpin_lock(&rq->lock); | |
5e16bbc2 | 1252 | rq = move_queued_task(rq, p, dest_cpu); |
cbce1a68 PZ |
1253 | lockdep_pin_lock(&rq->lock); |
1254 | } | |
5cc389bc PZ |
1255 | out: |
1256 | task_rq_unlock(rq, p, &flags); | |
1257 | ||
1258 | return ret; | |
1259 | } | |
25834c73 PZ |
1260 | |
1261 | int set_cpus_allowed_ptr(struct task_struct *p, const struct cpumask *new_mask) | |
1262 | { | |
1263 | return __set_cpus_allowed_ptr(p, new_mask, false); | |
1264 | } | |
5cc389bc PZ |
1265 | EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
1266 | ||
dd41f596 | 1267 | void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
c65cc870 | 1268 | { |
e2912009 PZ |
1269 | #ifdef CONFIG_SCHED_DEBUG |
1270 | /* | |
1271 | * We should never call set_task_cpu() on a blocked task, | |
1272 | * ttwu() will sort out the placement. | |
1273 | */ | |
077614ee | 1274 | WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING && |
e2336f6e | 1275 | !p->on_rq); |
0122ec5b | 1276 | |
3ea94de1 JP |
1277 | /* |
1278 | * Migrating fair class task must have p->on_rq = TASK_ON_RQ_MIGRATING, | |
1279 | * because schedstat_wait_{start,end} rebase migrating task's wait_start | |
1280 | * time relying on p->on_rq. | |
1281 | */ | |
1282 | WARN_ON_ONCE(p->state == TASK_RUNNING && | |
1283 | p->sched_class == &fair_sched_class && | |
1284 | (p->on_rq && !task_on_rq_migrating(p))); | |
1285 | ||
0122ec5b | 1286 | #ifdef CONFIG_LOCKDEP |
6c6c54e1 PZ |
1287 | /* |
1288 | * The caller should hold either p->pi_lock or rq->lock, when changing | |
1289 | * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. | |
1290 | * | |
1291 | * sched_move_task() holds both and thus holding either pins the cgroup, | |
8323f26c | 1292 | * see task_group(). |
6c6c54e1 PZ |
1293 | * |
1294 | * Furthermore, all task_rq users should acquire both locks, see | |
1295 | * task_rq_lock(). | |
1296 | */ | |
0122ec5b PZ |
1297 | WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || |
1298 | lockdep_is_held(&task_rq(p)->lock))); | |
1299 | #endif | |
e2912009 PZ |
1300 | #endif |
1301 | ||
de1d7286 | 1302 | trace_sched_migrate_task(p, new_cpu); |
cbc34ed1 | 1303 | |
0c69774e | 1304 | if (task_cpu(p) != new_cpu) { |
0a74bef8 | 1305 | if (p->sched_class->migrate_task_rq) |
5a4fd036 | 1306 | p->sched_class->migrate_task_rq(p); |
0c69774e | 1307 | p->se.nr_migrations++; |
ff303e66 | 1308 | perf_event_task_migrate(p); |
0c69774e | 1309 | } |
dd41f596 IM |
1310 | |
1311 | __set_task_cpu(p, new_cpu); | |
c65cc870 IM |
1312 | } |
1313 | ||
ac66f547 PZ |
1314 | static void __migrate_swap_task(struct task_struct *p, int cpu) |
1315 | { | |
da0c1e65 | 1316 | if (task_on_rq_queued(p)) { |
ac66f547 PZ |
1317 | struct rq *src_rq, *dst_rq; |
1318 | ||
1319 | src_rq = task_rq(p); | |
1320 | dst_rq = cpu_rq(cpu); | |
1321 | ||
3ea94de1 | 1322 | p->on_rq = TASK_ON_RQ_MIGRATING; |
ac66f547 PZ |
1323 | deactivate_task(src_rq, p, 0); |
1324 | set_task_cpu(p, cpu); | |
1325 | activate_task(dst_rq, p, 0); | |
3ea94de1 | 1326 | p->on_rq = TASK_ON_RQ_QUEUED; |
ac66f547 PZ |
1327 | check_preempt_curr(dst_rq, p, 0); |
1328 | } else { | |
1329 | /* | |
1330 | * Task isn't running anymore; make it appear like we migrated | |
1331 | * it before it went to sleep. This means on wakeup we make the | |
1332 | * previous cpu our targer instead of where it really is. | |
1333 | */ | |
1334 | p->wake_cpu = cpu; | |
1335 | } | |
1336 | } | |
1337 | ||
1338 | struct migration_swap_arg { | |
1339 | struct task_struct *src_task, *dst_task; | |
1340 | int src_cpu, dst_cpu; | |
1341 | }; | |
1342 | ||
1343 | static int migrate_swap_stop(void *data) | |
1344 | { | |
1345 | struct migration_swap_arg *arg = data; | |
1346 | struct rq *src_rq, *dst_rq; | |
1347 | int ret = -EAGAIN; | |
1348 | ||
62694cd5 PZ |
1349 | if (!cpu_active(arg->src_cpu) || !cpu_active(arg->dst_cpu)) |
1350 | return -EAGAIN; | |
1351 | ||
ac66f547 PZ |
1352 | src_rq = cpu_rq(arg->src_cpu); |
1353 | dst_rq = cpu_rq(arg->dst_cpu); | |
1354 | ||
74602315 PZ |
1355 | double_raw_lock(&arg->src_task->pi_lock, |
1356 | &arg->dst_task->pi_lock); | |
ac66f547 | 1357 | double_rq_lock(src_rq, dst_rq); |
62694cd5 | 1358 | |
ac66f547 PZ |
1359 | if (task_cpu(arg->dst_task) != arg->dst_cpu) |
1360 | goto unlock; | |
1361 | ||
1362 | if (task_cpu(arg->src_task) != arg->src_cpu) | |
1363 | goto unlock; | |
1364 | ||
1365 | if (!cpumask_test_cpu(arg->dst_cpu, tsk_cpus_allowed(arg->src_task))) | |
1366 | goto unlock; | |
1367 | ||
1368 | if (!cpumask_test_cpu(arg->src_cpu, tsk_cpus_allowed(arg->dst_task))) | |
1369 | goto unlock; | |
1370 | ||
1371 | __migrate_swap_task(arg->src_task, arg->dst_cpu); | |
1372 | __migrate_swap_task(arg->dst_task, arg->src_cpu); | |
1373 | ||
1374 | ret = 0; | |
1375 | ||
1376 | unlock: | |
1377 | double_rq_unlock(src_rq, dst_rq); | |
74602315 PZ |
1378 | raw_spin_unlock(&arg->dst_task->pi_lock); |
1379 | raw_spin_unlock(&arg->src_task->pi_lock); | |
ac66f547 PZ |
1380 | |
1381 | return ret; | |
1382 | } | |
1383 | ||
1384 | /* | |
1385 | * Cross migrate two tasks | |
1386 | */ | |
1387 | int migrate_swap(struct task_struct *cur, struct task_struct *p) | |
1388 | { | |
1389 | struct migration_swap_arg arg; | |
1390 | int ret = -EINVAL; | |
1391 | ||
ac66f547 PZ |
1392 | arg = (struct migration_swap_arg){ |
1393 | .src_task = cur, | |
1394 | .src_cpu = task_cpu(cur), | |
1395 | .dst_task = p, | |
1396 | .dst_cpu = task_cpu(p), | |
1397 | }; | |
1398 | ||
1399 | if (arg.src_cpu == arg.dst_cpu) | |
1400 | goto out; | |
1401 | ||
6acce3ef PZ |
1402 | /* |
1403 | * These three tests are all lockless; this is OK since all of them | |
1404 | * will be re-checked with proper locks held further down the line. | |
1405 | */ | |
ac66f547 PZ |
1406 | if (!cpu_active(arg.src_cpu) || !cpu_active(arg.dst_cpu)) |
1407 | goto out; | |
1408 | ||
1409 | if (!cpumask_test_cpu(arg.dst_cpu, tsk_cpus_allowed(arg.src_task))) | |
1410 | goto out; | |
1411 | ||
1412 | if (!cpumask_test_cpu(arg.src_cpu, tsk_cpus_allowed(arg.dst_task))) | |
1413 | goto out; | |
1414 | ||
286549dc | 1415 | trace_sched_swap_numa(cur, arg.src_cpu, p, arg.dst_cpu); |
ac66f547 PZ |
1416 | ret = stop_two_cpus(arg.dst_cpu, arg.src_cpu, migrate_swap_stop, &arg); |
1417 | ||
1418 | out: | |
ac66f547 PZ |
1419 | return ret; |
1420 | } | |
1421 | ||
1da177e4 LT |
1422 | /* |
1423 | * wait_task_inactive - wait for a thread to unschedule. | |
1424 | * | |
85ba2d86 RM |
1425 | * If @match_state is nonzero, it's the @p->state value just checked and |
1426 | * not expected to change. If it changes, i.e. @p might have woken up, | |
1427 | * then return zero. When we succeed in waiting for @p to be off its CPU, | |
1428 | * we return a positive number (its total switch count). If a second call | |
1429 | * a short while later returns the same number, the caller can be sure that | |
1430 | * @p has remained unscheduled the whole time. | |
1431 | * | |
1da177e4 LT |
1432 | * The caller must ensure that the task *will* unschedule sometime soon, |
1433 | * else this function might spin for a *long* time. This function can't | |
1434 | * be called with interrupts off, or it may introduce deadlock with | |
1435 | * smp_call_function() if an IPI is sent by the same process we are | |
1436 | * waiting to become inactive. | |
1437 | */ | |
85ba2d86 | 1438 | unsigned long wait_task_inactive(struct task_struct *p, long match_state) |
1da177e4 LT |
1439 | { |
1440 | unsigned long flags; | |
da0c1e65 | 1441 | int running, queued; |
85ba2d86 | 1442 | unsigned long ncsw; |
70b97a7f | 1443 | struct rq *rq; |
1da177e4 | 1444 | |
3a5c359a AK |
1445 | for (;;) { |
1446 | /* | |
1447 | * We do the initial early heuristics without holding | |
1448 | * any task-queue locks at all. We'll only try to get | |
1449 | * the runqueue lock when things look like they will | |
1450 | * work out! | |
1451 | */ | |
1452 | rq = task_rq(p); | |
fa490cfd | 1453 | |
3a5c359a AK |
1454 | /* |
1455 | * If the task is actively running on another CPU | |
1456 | * still, just relax and busy-wait without holding | |
1457 | * any locks. | |
1458 | * | |
1459 | * NOTE! Since we don't hold any locks, it's not | |
1460 | * even sure that "rq" stays as the right runqueue! | |
1461 | * But we don't care, since "task_running()" will | |
1462 | * return false if the runqueue has changed and p | |
1463 | * is actually now running somewhere else! | |
1464 | */ | |
85ba2d86 RM |
1465 | while (task_running(rq, p)) { |
1466 | if (match_state && unlikely(p->state != match_state)) | |
1467 | return 0; | |
3a5c359a | 1468 | cpu_relax(); |
85ba2d86 | 1469 | } |
fa490cfd | 1470 | |
3a5c359a AK |
1471 | /* |
1472 | * Ok, time to look more closely! We need the rq | |
1473 | * lock now, to be *sure*. If we're wrong, we'll | |
1474 | * just go back and repeat. | |
1475 | */ | |
1476 | rq = task_rq_lock(p, &flags); | |
27a9da65 | 1477 | trace_sched_wait_task(p); |
3a5c359a | 1478 | running = task_running(rq, p); |
da0c1e65 | 1479 | queued = task_on_rq_queued(p); |
85ba2d86 | 1480 | ncsw = 0; |
f31e11d8 | 1481 | if (!match_state || p->state == match_state) |
93dcf55f | 1482 | ncsw = p->nvcsw | LONG_MIN; /* sets MSB */ |
0122ec5b | 1483 | task_rq_unlock(rq, p, &flags); |
fa490cfd | 1484 | |
85ba2d86 RM |
1485 | /* |
1486 | * If it changed from the expected state, bail out now. | |
1487 | */ | |
1488 | if (unlikely(!ncsw)) | |
1489 | break; | |
1490 | ||
3a5c359a AK |
1491 | /* |
1492 | * Was it really running after all now that we | |
1493 | * checked with the proper locks actually held? | |
1494 | * | |
1495 | * Oops. Go back and try again.. | |
1496 | */ | |
1497 | if (unlikely(running)) { | |
1498 | cpu_relax(); | |
1499 | continue; | |
1500 | } | |
fa490cfd | 1501 | |
3a5c359a AK |
1502 | /* |
1503 | * It's not enough that it's not actively running, | |
1504 | * it must be off the runqueue _entirely_, and not | |
1505 | * preempted! | |
1506 | * | |
80dd99b3 | 1507 | * So if it was still runnable (but just not actively |
3a5c359a AK |
1508 | * running right now), it's preempted, and we should |
1509 | * yield - it could be a while. | |
1510 | */ | |
da0c1e65 | 1511 | if (unlikely(queued)) { |
8eb90c30 TG |
1512 | ktime_t to = ktime_set(0, NSEC_PER_SEC/HZ); |
1513 | ||
1514 | set_current_state(TASK_UNINTERRUPTIBLE); | |
1515 | schedule_hrtimeout(&to, HRTIMER_MODE_REL); | |
3a5c359a AK |
1516 | continue; |
1517 | } | |
fa490cfd | 1518 | |
3a5c359a AK |
1519 | /* |
1520 | * Ahh, all good. It wasn't running, and it wasn't | |
1521 | * runnable, which means that it will never become | |
1522 | * running in the future either. We're all done! | |
1523 | */ | |
1524 | break; | |
1525 | } | |
85ba2d86 RM |
1526 | |
1527 | return ncsw; | |
1da177e4 LT |
1528 | } |
1529 | ||
1530 | /*** | |
1531 | * kick_process - kick a running thread to enter/exit the kernel | |
1532 | * @p: the to-be-kicked thread | |
1533 | * | |
1534 | * Cause a process which is running on another CPU to enter | |
1535 | * kernel-mode, without any delay. (to get signals handled.) | |
1536 | * | |
25985edc | 1537 | * NOTE: this function doesn't have to take the runqueue lock, |
1da177e4 LT |
1538 | * because all it wants to ensure is that the remote task enters |
1539 | * the kernel. If the IPI races and the task has been migrated | |
1540 | * to another CPU then no harm is done and the purpose has been | |
1541 | * achieved as well. | |
1542 | */ | |
36c8b586 | 1543 | void kick_process(struct task_struct *p) |
1da177e4 LT |
1544 | { |
1545 | int cpu; | |
1546 | ||
1547 | preempt_disable(); | |
1548 | cpu = task_cpu(p); | |
1549 | if ((cpu != smp_processor_id()) && task_curr(p)) | |
1550 | smp_send_reschedule(cpu); | |
1551 | preempt_enable(); | |
1552 | } | |
b43e3521 | 1553 | EXPORT_SYMBOL_GPL(kick_process); |
1da177e4 | 1554 | |
30da688e | 1555 | /* |
013fdb80 | 1556 | * ->cpus_allowed is protected by both rq->lock and p->pi_lock |
30da688e | 1557 | */ |
5da9a0fb PZ |
1558 | static int select_fallback_rq(int cpu, struct task_struct *p) |
1559 | { | |
aa00d89c TC |
1560 | int nid = cpu_to_node(cpu); |
1561 | const struct cpumask *nodemask = NULL; | |
2baab4e9 PZ |
1562 | enum { cpuset, possible, fail } state = cpuset; |
1563 | int dest_cpu; | |
5da9a0fb | 1564 | |
aa00d89c TC |
1565 | /* |
1566 | * If the node that the cpu is on has been offlined, cpu_to_node() | |
1567 | * will return -1. There is no cpu on the node, and we should | |
1568 | * select the cpu on the other node. | |
1569 | */ | |
1570 | if (nid != -1) { | |
1571 | nodemask = cpumask_of_node(nid); | |
1572 | ||
1573 | /* Look for allowed, online CPU in same node. */ | |
1574 | for_each_cpu(dest_cpu, nodemask) { | |
1575 | if (!cpu_online(dest_cpu)) | |
1576 | continue; | |
1577 | if (!cpu_active(dest_cpu)) | |
1578 | continue; | |
1579 | if (cpumask_test_cpu(dest_cpu, tsk_cpus_allowed(p))) | |
1580 | return dest_cpu; | |
1581 | } | |
2baab4e9 | 1582 | } |
5da9a0fb | 1583 | |
2baab4e9 PZ |
1584 | for (;;) { |
1585 | /* Any allowed, online CPU? */ | |
e3831edd | 1586 | for_each_cpu(dest_cpu, tsk_cpus_allowed(p)) { |
2baab4e9 PZ |
1587 | if (!cpu_online(dest_cpu)) |
1588 | continue; | |
1589 | if (!cpu_active(dest_cpu)) | |
1590 | continue; | |
1591 | goto out; | |
1592 | } | |
5da9a0fb | 1593 | |
e73e85f0 | 1594 | /* No more Mr. Nice Guy. */ |
2baab4e9 PZ |
1595 | switch (state) { |
1596 | case cpuset: | |
e73e85f0 ON |
1597 | if (IS_ENABLED(CONFIG_CPUSETS)) { |
1598 | cpuset_cpus_allowed_fallback(p); | |
1599 | state = possible; | |
1600 | break; | |
1601 | } | |
1602 | /* fall-through */ | |
2baab4e9 PZ |
1603 | case possible: |
1604 | do_set_cpus_allowed(p, cpu_possible_mask); | |
1605 | state = fail; | |
1606 | break; | |
1607 | ||
1608 | case fail: | |
1609 | BUG(); | |
1610 | break; | |
1611 | } | |
1612 | } | |
1613 | ||
1614 | out: | |
1615 | if (state != cpuset) { | |
1616 | /* | |
1617 | * Don't tell them about moving exiting tasks or | |
1618 | * kernel threads (both mm NULL), since they never | |
1619 | * leave kernel. | |
1620 | */ | |
1621 | if (p->mm && printk_ratelimit()) { | |
aac74dc4 | 1622 | printk_deferred("process %d (%s) no longer affine to cpu%d\n", |
2baab4e9 PZ |
1623 | task_pid_nr(p), p->comm, cpu); |
1624 | } | |
5da9a0fb PZ |
1625 | } |
1626 | ||
1627 | return dest_cpu; | |
1628 | } | |
1629 | ||
e2912009 | 1630 | /* |
013fdb80 | 1631 | * The caller (fork, wakeup) owns p->pi_lock, ->cpus_allowed is stable. |
e2912009 | 1632 | */ |
970b13ba | 1633 | static inline |
ac66f547 | 1634 | int select_task_rq(struct task_struct *p, int cpu, int sd_flags, int wake_flags) |
970b13ba | 1635 | { |
cbce1a68 PZ |
1636 | lockdep_assert_held(&p->pi_lock); |
1637 | ||
6c1d9410 WL |
1638 | if (p->nr_cpus_allowed > 1) |
1639 | cpu = p->sched_class->select_task_rq(p, cpu, sd_flags, wake_flags); | |
e2912009 PZ |
1640 | |
1641 | /* | |
1642 | * In order not to call set_task_cpu() on a blocking task we need | |
1643 | * to rely on ttwu() to place the task on a valid ->cpus_allowed | |
1644 | * cpu. | |
1645 | * | |
1646 | * Since this is common to all placement strategies, this lives here. | |
1647 | * | |
1648 | * [ this allows ->select_task() to simply return task_cpu(p) and | |
1649 | * not worry about this generic constraint ] | |
1650 | */ | |
fa17b507 | 1651 | if (unlikely(!cpumask_test_cpu(cpu, tsk_cpus_allowed(p)) || |
70f11205 | 1652 | !cpu_online(cpu))) |
5da9a0fb | 1653 | cpu = select_fallback_rq(task_cpu(p), p); |
e2912009 PZ |
1654 | |
1655 | return cpu; | |
970b13ba | 1656 | } |
09a40af5 MG |
1657 | |
1658 | static void update_avg(u64 *avg, u64 sample) | |
1659 | { | |
1660 | s64 diff = sample - *avg; | |
1661 | *avg += diff >> 3; | |
1662 | } | |
25834c73 PZ |
1663 | |
1664 | #else | |
1665 | ||
1666 | static inline int __set_cpus_allowed_ptr(struct task_struct *p, | |
1667 | const struct cpumask *new_mask, bool check) | |
1668 | { | |
1669 | return set_cpus_allowed_ptr(p, new_mask); | |
1670 | } | |
1671 | ||
5cc389bc | 1672 | #endif /* CONFIG_SMP */ |
970b13ba | 1673 | |
d7c01d27 | 1674 | static void |
b84cb5df | 1675 | ttwu_stat(struct task_struct *p, int cpu, int wake_flags) |
9ed3811a | 1676 | { |
d7c01d27 | 1677 | #ifdef CONFIG_SCHEDSTATS |
b84cb5df PZ |
1678 | struct rq *rq = this_rq(); |
1679 | ||
d7c01d27 PZ |
1680 | #ifdef CONFIG_SMP |
1681 | int this_cpu = smp_processor_id(); | |
1682 | ||
1683 | if (cpu == this_cpu) { | |
1684 | schedstat_inc(rq, ttwu_local); | |
1685 | schedstat_inc(p, se.statistics.nr_wakeups_local); | |
1686 | } else { | |
1687 | struct sched_domain *sd; | |
1688 | ||
1689 | schedstat_inc(p, se.statistics.nr_wakeups_remote); | |
057f3fad | 1690 | rcu_read_lock(); |
d7c01d27 PZ |
1691 | for_each_domain(this_cpu, sd) { |
1692 | if (cpumask_test_cpu(cpu, sched_domain_span(sd))) { | |
1693 | schedstat_inc(sd, ttwu_wake_remote); | |
1694 | break; | |
1695 | } | |
1696 | } | |
057f3fad | 1697 | rcu_read_unlock(); |
d7c01d27 | 1698 | } |
f339b9dc PZ |
1699 | |
1700 | if (wake_flags & WF_MIGRATED) | |
1701 | schedstat_inc(p, se.statistics.nr_wakeups_migrate); | |
1702 | ||
d7c01d27 PZ |
1703 | #endif /* CONFIG_SMP */ |
1704 | ||
1705 | schedstat_inc(rq, ttwu_count); | |
9ed3811a | 1706 | schedstat_inc(p, se.statistics.nr_wakeups); |
d7c01d27 PZ |
1707 | |
1708 | if (wake_flags & WF_SYNC) | |
9ed3811a | 1709 | schedstat_inc(p, se.statistics.nr_wakeups_sync); |
d7c01d27 | 1710 | |
d7c01d27 PZ |
1711 | #endif /* CONFIG_SCHEDSTATS */ |
1712 | } | |
1713 | ||
1de64443 | 1714 | static inline void ttwu_activate(struct rq *rq, struct task_struct *p, int en_flags) |
d7c01d27 | 1715 | { |
9ed3811a | 1716 | activate_task(rq, p, en_flags); |
da0c1e65 | 1717 | p->on_rq = TASK_ON_RQ_QUEUED; |
c2f7115e PZ |
1718 | |
1719 | /* if a worker is waking up, notify workqueue */ | |
1720 | if (p->flags & PF_WQ_WORKER) | |
1721 | wq_worker_waking_up(p, cpu_of(rq)); | |
9ed3811a TH |
1722 | } |
1723 | ||
23f41eeb PZ |
1724 | /* |
1725 | * Mark the task runnable and perform wakeup-preemption. | |
1726 | */ | |
89363381 | 1727 | static void |
23f41eeb | 1728 | ttwu_do_wakeup(struct rq *rq, struct task_struct *p, int wake_flags) |
9ed3811a | 1729 | { |
9ed3811a | 1730 | check_preempt_curr(rq, p, wake_flags); |
9ed3811a | 1731 | p->state = TASK_RUNNING; |
fbd705a0 PZ |
1732 | trace_sched_wakeup(p); |
1733 | ||
9ed3811a | 1734 | #ifdef CONFIG_SMP |
4c9a4bc8 PZ |
1735 | if (p->sched_class->task_woken) { |
1736 | /* | |
cbce1a68 PZ |
1737 | * Our task @p is fully woken up and running; so its safe to |
1738 | * drop the rq->lock, hereafter rq is only used for statistics. | |
4c9a4bc8 | 1739 | */ |
cbce1a68 | 1740 | lockdep_unpin_lock(&rq->lock); |
9ed3811a | 1741 | p->sched_class->task_woken(rq, p); |
cbce1a68 | 1742 | lockdep_pin_lock(&rq->lock); |
4c9a4bc8 | 1743 | } |
9ed3811a | 1744 | |
e69c6341 | 1745 | if (rq->idle_stamp) { |
78becc27 | 1746 | u64 delta = rq_clock(rq) - rq->idle_stamp; |
9bd721c5 | 1747 | u64 max = 2*rq->max_idle_balance_cost; |
9ed3811a | 1748 | |
abfafa54 JL |
1749 | update_avg(&rq->avg_idle, delta); |
1750 | ||
1751 | if (rq->avg_idle > max) | |
9ed3811a | 1752 | rq->avg_idle = max; |
abfafa54 | 1753 | |
9ed3811a TH |
1754 | rq->idle_stamp = 0; |
1755 | } | |
1756 | #endif | |
1757 | } | |
1758 | ||
c05fbafb PZ |
1759 | static void |
1760 | ttwu_do_activate(struct rq *rq, struct task_struct *p, int wake_flags) | |
1761 | { | |
cbce1a68 PZ |
1762 | lockdep_assert_held(&rq->lock); |
1763 | ||
c05fbafb PZ |
1764 | #ifdef CONFIG_SMP |
1765 | if (p->sched_contributes_to_load) | |
1766 | rq->nr_uninterruptible--; | |
1767 | #endif | |
1768 | ||
1769 | ttwu_activate(rq, p, ENQUEUE_WAKEUP | ENQUEUE_WAKING); | |
1770 | ttwu_do_wakeup(rq, p, wake_flags); | |
1771 | } | |
1772 | ||
1773 | /* | |
1774 | * Called in case the task @p isn't fully descheduled from its runqueue, | |
1775 | * in this case we must do a remote wakeup. Its a 'light' wakeup though, | |
1776 | * since all we need to do is flip p->state to TASK_RUNNING, since | |
1777 | * the task is still ->on_rq. | |
1778 | */ | |
1779 | static int ttwu_remote(struct task_struct *p, int wake_flags) | |
1780 | { | |
1781 | struct rq *rq; | |
1782 | int ret = 0; | |
1783 | ||
1784 | rq = __task_rq_lock(p); | |
da0c1e65 | 1785 | if (task_on_rq_queued(p)) { |
1ad4ec0d FW |
1786 | /* check_preempt_curr() may use rq clock */ |
1787 | update_rq_clock(rq); | |
c05fbafb PZ |
1788 | ttwu_do_wakeup(rq, p, wake_flags); |
1789 | ret = 1; | |
1790 | } | |
1791 | __task_rq_unlock(rq); | |
1792 | ||
1793 | return ret; | |
1794 | } | |
1795 | ||
317f3941 | 1796 | #ifdef CONFIG_SMP |
e3baac47 | 1797 | void sched_ttwu_pending(void) |
317f3941 PZ |
1798 | { |
1799 | struct rq *rq = this_rq(); | |
fa14ff4a PZ |
1800 | struct llist_node *llist = llist_del_all(&rq->wake_list); |
1801 | struct task_struct *p; | |
e3baac47 | 1802 | unsigned long flags; |
317f3941 | 1803 | |
e3baac47 PZ |
1804 | if (!llist) |
1805 | return; | |
1806 | ||
1807 | raw_spin_lock_irqsave(&rq->lock, flags); | |
cbce1a68 | 1808 | lockdep_pin_lock(&rq->lock); |
317f3941 | 1809 | |
fa14ff4a PZ |
1810 | while (llist) { |
1811 | p = llist_entry(llist, struct task_struct, wake_entry); | |
1812 | llist = llist_next(llist); | |
317f3941 PZ |
1813 | ttwu_do_activate(rq, p, 0); |
1814 | } | |
1815 | ||
cbce1a68 | 1816 | lockdep_unpin_lock(&rq->lock); |
e3baac47 | 1817 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
317f3941 PZ |
1818 | } |
1819 | ||
1820 | void scheduler_ipi(void) | |
1821 | { | |
f27dde8d PZ |
1822 | /* |
1823 | * Fold TIF_NEED_RESCHED into the preempt_count; anybody setting | |
1824 | * TIF_NEED_RESCHED remotely (for the first time) will also send | |
1825 | * this IPI. | |
1826 | */ | |
8cb75e0c | 1827 | preempt_fold_need_resched(); |
f27dde8d | 1828 | |
fd2ac4f4 | 1829 | if (llist_empty(&this_rq()->wake_list) && !got_nohz_idle_kick()) |
c5d753a5 PZ |
1830 | return; |
1831 | ||
1832 | /* | |
1833 | * Not all reschedule IPI handlers call irq_enter/irq_exit, since | |
1834 | * traditionally all their work was done from the interrupt return | |
1835 | * path. Now that we actually do some work, we need to make sure | |
1836 | * we do call them. | |
1837 | * | |
1838 | * Some archs already do call them, luckily irq_enter/exit nest | |
1839 | * properly. | |
1840 | * | |
1841 | * Arguably we should visit all archs and update all handlers, | |
1842 | * however a fair share of IPIs are still resched only so this would | |
1843 | * somewhat pessimize the simple resched case. | |
1844 | */ | |
1845 | irq_enter(); | |
fa14ff4a | 1846 | sched_ttwu_pending(); |
ca38062e SS |
1847 | |
1848 | /* | |
1849 | * Check if someone kicked us for doing the nohz idle load balance. | |
1850 | */ | |
873b4c65 | 1851 | if (unlikely(got_nohz_idle_kick())) { |
6eb57e0d | 1852 | this_rq()->idle_balance = 1; |
ca38062e | 1853 | raise_softirq_irqoff(SCHED_SOFTIRQ); |
6eb57e0d | 1854 | } |
c5d753a5 | 1855 | irq_exit(); |
317f3941 PZ |
1856 | } |
1857 | ||
1858 | static void ttwu_queue_remote(struct task_struct *p, int cpu) | |
1859 | { | |
e3baac47 PZ |
1860 | struct rq *rq = cpu_rq(cpu); |
1861 | ||
1862 | if (llist_add(&p->wake_entry, &cpu_rq(cpu)->wake_list)) { | |
1863 | if (!set_nr_if_polling(rq->idle)) | |
1864 | smp_send_reschedule(cpu); | |
1865 | else | |
1866 | trace_sched_wake_idle_without_ipi(cpu); | |
1867 | } | |
317f3941 | 1868 | } |
d6aa8f85 | 1869 | |
f6be8af1 CL |
1870 | void wake_up_if_idle(int cpu) |
1871 | { | |
1872 | struct rq *rq = cpu_rq(cpu); | |
1873 | unsigned long flags; | |
1874 | ||
fd7de1e8 AL |
1875 | rcu_read_lock(); |
1876 | ||
1877 | if (!is_idle_task(rcu_dereference(rq->curr))) | |
1878 | goto out; | |
f6be8af1 CL |
1879 | |
1880 | if (set_nr_if_polling(rq->idle)) { | |
1881 | trace_sched_wake_idle_without_ipi(cpu); | |
1882 | } else { | |
1883 | raw_spin_lock_irqsave(&rq->lock, flags); | |
1884 | if (is_idle_task(rq->curr)) | |
1885 | smp_send_reschedule(cpu); | |
1886 | /* Else cpu is not in idle, do nothing here */ | |
1887 | raw_spin_unlock_irqrestore(&rq->lock, flags); | |
1888 | } | |
fd7de1e8 AL |
1889 | |
1890 | out: | |
1891 | rcu_read_unlock(); | |
f6be8af1 CL |
1892 | } |
1893 | ||
39be3501 | 1894 | bool cpus_share_cache(int this_cpu, int that_cpu) |
518cd623 PZ |
1895 | { |
1896 | return per_cpu(sd_llc_id, this_cpu) == per_cpu(sd_llc_id, that_cpu); | |
1897 | } | |
d6aa8f85 | 1898 | #endif /* CONFIG_SMP */ |
317f3941 | 1899 | |
c05fbafb PZ |
1900 | static void ttwu_queue(struct task_struct *p, int cpu) |
1901 | { | |
1902 | struct rq *rq = cpu_rq(cpu); | |
1903 | ||
17d9f311 | 1904 | #if defined(CONFIG_SMP) |
39be3501 | 1905 | if (sched_feat(TTWU_QUEUE) && !cpus_share_cache(smp_processor_id(), cpu)) { |
f01114cb | 1906 | sched_clock_cpu(cpu); /* sync clocks x-cpu */ |
317f3941 PZ |
1907 | ttwu_queue_remote(p, cpu); |
1908 | return; | |
1909 | } | |
1910 | #endif | |
1911 | ||
c05fbafb | 1912 | raw_spin_lock(&rq->lock); |
cbce1a68 | 1913 | lockdep_pin_lock(&rq->lock); |
c05fbafb | 1914 | ttwu_do_activate(rq, p, 0); |
cbce1a68 | 1915 | lockdep_unpin_lock(&rq->lock); |
c05fbafb | 1916 | raw_spin_unlock(&rq->lock); |
9ed3811a TH |
1917 | } |
1918 | ||
8643cda5 PZ |
1919 | /* |
1920 | * Notes on Program-Order guarantees on SMP systems. | |
1921 | * | |
1922 | * MIGRATION | |
1923 | * | |
1924 | * The basic program-order guarantee on SMP systems is that when a task [t] | |
1925 | * migrates, all its activity on its old cpu [c0] happens-before any subsequent | |
1926 | * execution on its new cpu [c1]. | |
1927 | * | |
1928 | * For migration (of runnable tasks) this is provided by the following means: | |
1929 | * | |
1930 | * A) UNLOCK of the rq(c0)->lock scheduling out task t | |
1931 | * B) migration for t is required to synchronize *both* rq(c0)->lock and | |
1932 | * rq(c1)->lock (if not at the same time, then in that order). | |
1933 | * C) LOCK of the rq(c1)->lock scheduling in task | |
1934 | * | |
1935 | * Transitivity guarantees that B happens after A and C after B. | |
1936 | * Note: we only require RCpc transitivity. | |
1937 | * Note: the cpu doing B need not be c0 or c1 | |
1938 | * | |
1939 | * Example: | |
1940 | * | |
1941 | * CPU0 CPU1 CPU2 | |
1942 | * | |
1943 | * LOCK rq(0)->lock | |
1944 | * sched-out X | |
1945 | * sched-in Y | |
1946 | * UNLOCK rq(0)->lock | |
1947 | * | |
1948 | * LOCK rq(0)->lock // orders against CPU0 | |
1949 | * dequeue X | |
1950 | * UNLOCK rq(0)->lock | |
1951 | * | |
1952 | * LOCK rq(1)->lock | |
1953 | * enqueue X | |
1954 | * UNLOCK rq(1)->lock | |
1955 | * | |
1956 | * LOCK rq(1)->lock // orders against CPU2 | |
1957 | * sched-out Z | |
1958 | * sched-in X | |
1959 | * UNLOCK rq(1)->lock | |
1960 | * | |
1961 | * | |
1962 | * BLOCKING -- aka. SLEEP + WAKEUP | |
1963 | * | |
1964 | * For blocking we (obviously) need to provide the same guarantee as for | |
1965 | * migration. However the means are completely different as there is no lock | |
1966 | * chain to provide order. Instead we do: | |
1967 | * | |
1968 | * 1) smp_store_release(X->on_cpu, 0) | |
1969 | * 2) smp_cond_acquire(!X->on_cpu) | |
1970 | * | |
1971 | * Example: | |
1972 | * | |
1973 | * CPU0 (schedule) CPU1 (try_to_wake_up) CPU2 (schedule) | |
1974 | * | |
1975 | * LOCK rq(0)->lock LOCK X->pi_lock | |
1976 | * dequeue X | |
1977 | * sched-out X | |
1978 | * smp_store_release(X->on_cpu, 0); | |
1979 | * | |
1980 | * smp_cond_acquire(!X->on_cpu); | |
1981 | * X->state = WAKING | |
1982 | * set_task_cpu(X,2) | |
1983 | * | |
1984 | * LOCK rq(2)->lock | |
1985 | * enqueue X | |
1986 | * X->state = RUNNING | |
1987 | * UNLOCK rq(2)->lock | |
1988 | * | |
1989 | * LOCK rq(2)->lock // orders against CPU1 | |
1990 | * sched-out Z | |
1991 | * sched-in X | |
1992 | * UNLOCK rq(2)->lock | |
1993 | * | |
1994 | * UNLOCK X->pi_lock | |
1995 | * UNLOCK rq(0)->lock | |
1996 | * | |
1997 | * | |
1998 | * However; for wakeups there is a second guarantee we must provide, namely we | |
1999 | * must observe the state that lead to our wakeup. That is, not only must our | |
2000 | * task observe its own prior state, it must also observe the stores prior to | |
2001 | * its wakeup. | |
2002 | * | |
2003 | * This means that any means of doing remote wakeups must order the CPU doing | |
2004 | * the wakeup against the CPU the task is going to end up running on. This, | |
2005 | * however, is already required for the regular Program-Order guarantee above, | |
2006 | * since the waking CPU is the one issueing the ACQUIRE (smp_cond_acquire). | |
2007 | * | |
2008 | */ | |
2009 | ||
9ed3811a | 2010 | /** |
1da177e4 | 2011 | * try_to_wake_up - wake up a thread |
9ed3811a | 2012 | * @p: the thread to be awakened |
1da177e4 | 2013 | * @state: the mask of task states that can be woken |
9ed3811a | 2014 | * @wake_flags: wake modifier flags (WF_*) |
1da177e4 LT |
2015 | * |
2016 | * Put it on the run-queue if it's not already there. The "current" | |
2017 | * thread is always on the run-queue (except when the actual | |
2018 | * re-schedule is in progress), and as such you're allowed to do | |
2019 | * the simpler "current->state = TASK_RUNNING" to mark yourself | |
2020 | * runnable without the overhead of this. | |
2021 | * | |
e69f6186 | 2022 | * Return: %true if @p was woken up, %false if it was already running. |
9ed3811a | 2023 | * or @state didn't match @p's state. |
1da177e4 | 2024 | */ |
e4a52bcb PZ |
2025 | static int |
2026 | try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) | |
1da177e4 | 2027 | { |
1da177e4 | 2028 | unsigned long flags; |
c05fbafb | 2029 | int cpu, success = 0; |
2398f2c6 | 2030 | |
e0acd0a6 ON |
2031 | /* |
2032 | * If we are going to wake up a thread waiting for CONDITION we | |
2033 | * need to ensure that CONDITION=1 done by the caller can not be | |
2034 | * reordered with p->state check below. This pairs with mb() in | |
2035 | * set_current_state() the waiting thread does. | |
2036 | */ | |
2037 | smp_mb__before_spinlock(); | |
013fdb80 | 2038 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
e9c84311 | 2039 | if (!(p->state & state)) |
1da177e4 LT |
2040 | goto out; |
2041 | ||
fbd705a0 PZ |
2042 | trace_sched_waking(p); |
2043 | ||
c05fbafb | 2044 | success = 1; /* we're going to change ->state */ |
1da177e4 | 2045 | cpu = task_cpu(p); |
1da177e4 | 2046 | |
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 | */ |
b3e0b1b6 | 2079 | smp_cond_acquire(!p->on_cpu); |
1da177e4 | 2080 | |
a8e4f2ea | 2081 | p->sched_contributes_to_load = !!task_contributes_to_load(p); |
e9c84311 | 2082 | p->state = TASK_WAKING; |
e7693a36 | 2083 | |
e4a52bcb | 2084 | if (p->sched_class->task_waking) |
74f8e4b2 | 2085 | p->sched_class->task_waking(p); |
efbbd05a | 2086 | |
ac66f547 | 2087 | cpu = select_task_rq(p, p->wake_cpu, SD_BALANCE_WAKE, wake_flags); |
f339b9dc PZ |
2088 | if (task_cpu(p) != cpu) { |
2089 | wake_flags |= WF_MIGRATED; | |
e4a52bcb | 2090 | set_task_cpu(p, cpu); |
f339b9dc | 2091 | } |
1da177e4 | 2092 | #endif /* CONFIG_SMP */ |
1da177e4 | 2093 | |
c05fbafb PZ |
2094 | ttwu_queue(p, cpu); |
2095 | stat: | |
b84cb5df | 2096 | ttwu_stat(p, cpu, wake_flags); |
1da177e4 | 2097 | out: |
013fdb80 | 2098 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
2099 | |
2100 | return success; | |
2101 | } | |
2102 | ||
21aa9af0 TH |
2103 | /** |
2104 | * try_to_wake_up_local - try to wake up a local task with rq lock held | |
2105 | * @p: the thread to be awakened | |
2106 | * | |
2acca55e | 2107 | * Put @p on the run-queue if it's not already there. The caller must |
21aa9af0 | 2108 | * ensure that this_rq() is locked, @p is bound to this_rq() and not |
2acca55e | 2109 | * the current task. |
21aa9af0 TH |
2110 | */ |
2111 | static void try_to_wake_up_local(struct task_struct *p) | |
2112 | { | |
2113 | struct rq *rq = task_rq(p); | |
21aa9af0 | 2114 | |
383efcd0 TH |
2115 | if (WARN_ON_ONCE(rq != this_rq()) || |
2116 | WARN_ON_ONCE(p == current)) | |
2117 | return; | |
2118 | ||
21aa9af0 TH |
2119 | lockdep_assert_held(&rq->lock); |
2120 | ||
2acca55e | 2121 | if (!raw_spin_trylock(&p->pi_lock)) { |
cbce1a68 PZ |
2122 | /* |
2123 | * This is OK, because current is on_cpu, which avoids it being | |
2124 | * picked for load-balance and preemption/IRQs are still | |
2125 | * disabled avoiding further scheduler activity on it and we've | |
2126 | * not yet picked a replacement task. | |
2127 | */ | |
2128 | lockdep_unpin_lock(&rq->lock); | |
2acca55e PZ |
2129 | raw_spin_unlock(&rq->lock); |
2130 | raw_spin_lock(&p->pi_lock); | |
2131 | raw_spin_lock(&rq->lock); | |
cbce1a68 | 2132 | lockdep_pin_lock(&rq->lock); |
2acca55e PZ |
2133 | } |
2134 | ||
21aa9af0 | 2135 | if (!(p->state & TASK_NORMAL)) |
2acca55e | 2136 | goto out; |
21aa9af0 | 2137 | |
fbd705a0 PZ |
2138 | trace_sched_waking(p); |
2139 | ||
da0c1e65 | 2140 | if (!task_on_rq_queued(p)) |
d7c01d27 PZ |
2141 | ttwu_activate(rq, p, ENQUEUE_WAKEUP); |
2142 | ||
23f41eeb | 2143 | ttwu_do_wakeup(rq, p, 0); |
b84cb5df | 2144 | ttwu_stat(p, smp_processor_id(), 0); |
2acca55e PZ |
2145 | out: |
2146 | raw_spin_unlock(&p->pi_lock); | |
21aa9af0 TH |
2147 | } |
2148 | ||
50fa610a DH |
2149 | /** |
2150 | * wake_up_process - Wake up a specific process | |
2151 | * @p: The process to be woken up. | |
2152 | * | |
2153 | * Attempt to wake up the nominated process and move it to the set of runnable | |
e69f6186 YB |
2154 | * processes. |
2155 | * | |
2156 | * Return: 1 if the process was woken up, 0 if it was already running. | |
50fa610a DH |
2157 | * |
2158 | * It may be assumed that this function implies a write memory barrier before | |
2159 | * changing the task state if and only if any tasks are woken up. | |
2160 | */ | |
7ad5b3a5 | 2161 | int wake_up_process(struct task_struct *p) |
1da177e4 | 2162 | { |
9067ac85 | 2163 | return try_to_wake_up(p, TASK_NORMAL, 0); |
1da177e4 | 2164 | } |
1da177e4 LT |
2165 | EXPORT_SYMBOL(wake_up_process); |
2166 | ||
7ad5b3a5 | 2167 | int wake_up_state(struct task_struct *p, unsigned int state) |
1da177e4 LT |
2168 | { |
2169 | return try_to_wake_up(p, state, 0); | |
2170 | } | |
2171 | ||
a5e7be3b JL |
2172 | /* |
2173 | * This function clears the sched_dl_entity static params. | |
2174 | */ | |
2175 | void __dl_clear_params(struct task_struct *p) | |
2176 | { | |
2177 | struct sched_dl_entity *dl_se = &p->dl; | |
2178 | ||
2179 | dl_se->dl_runtime = 0; | |
2180 | dl_se->dl_deadline = 0; | |
2181 | dl_se->dl_period = 0; | |
2182 | dl_se->flags = 0; | |
2183 | dl_se->dl_bw = 0; | |
40767b0d PZ |
2184 | |
2185 | dl_se->dl_throttled = 0; | |
2186 | dl_se->dl_new = 1; | |
2187 | dl_se->dl_yielded = 0; | |
a5e7be3b JL |
2188 | } |
2189 | ||
1da177e4 LT |
2190 | /* |
2191 | * Perform scheduler related setup for a newly forked process p. | |
2192 | * p is forked by current. | |
dd41f596 IM |
2193 | * |
2194 | * __sched_fork() is basic setup used by init_idle() too: | |
2195 | */ | |
5e1576ed | 2196 | static void __sched_fork(unsigned long clone_flags, struct task_struct *p) |
dd41f596 | 2197 | { |
fd2f4419 PZ |
2198 | p->on_rq = 0; |
2199 | ||
2200 | p->se.on_rq = 0; | |
dd41f596 IM |
2201 | p->se.exec_start = 0; |
2202 | p->se.sum_exec_runtime = 0; | |
f6cf891c | 2203 | p->se.prev_sum_exec_runtime = 0; |
6c594c21 | 2204 | p->se.nr_migrations = 0; |
da7a735e | 2205 | p->se.vruntime = 0; |
fd2f4419 | 2206 | INIT_LIST_HEAD(&p->se.group_node); |
6cfb0d5d | 2207 | |
ad936d86 BP |
2208 | #ifdef CONFIG_FAIR_GROUP_SCHED |
2209 | p->se.cfs_rq = NULL; | |
2210 | #endif | |
2211 | ||
6cfb0d5d | 2212 | #ifdef CONFIG_SCHEDSTATS |
41acab88 | 2213 | memset(&p->se.statistics, 0, sizeof(p->se.statistics)); |
6cfb0d5d | 2214 | #endif |
476d139c | 2215 | |
aab03e05 | 2216 | RB_CLEAR_NODE(&p->dl.rb_node); |
40767b0d | 2217 | init_dl_task_timer(&p->dl); |
a5e7be3b | 2218 | __dl_clear_params(p); |
aab03e05 | 2219 | |
fa717060 | 2220 | INIT_LIST_HEAD(&p->rt.run_list); |
476d139c | 2221 | |
e107be36 AK |
2222 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2223 | INIT_HLIST_HEAD(&p->preempt_notifiers); | |
2224 | #endif | |
cbee9f88 PZ |
2225 | |
2226 | #ifdef CONFIG_NUMA_BALANCING | |
2227 | if (p->mm && atomic_read(&p->mm->mm_users) == 1) { | |
7e8d16b6 | 2228 | p->mm->numa_next_scan = jiffies + msecs_to_jiffies(sysctl_numa_balancing_scan_delay); |
cbee9f88 PZ |
2229 | p->mm->numa_scan_seq = 0; |
2230 | } | |
2231 | ||
5e1576ed RR |
2232 | if (clone_flags & CLONE_VM) |
2233 | p->numa_preferred_nid = current->numa_preferred_nid; | |
2234 | else | |
2235 | p->numa_preferred_nid = -1; | |
2236 | ||
cbee9f88 PZ |
2237 | p->node_stamp = 0ULL; |
2238 | p->numa_scan_seq = p->mm ? p->mm->numa_scan_seq : 0; | |
4b96a29b | 2239 | p->numa_scan_period = sysctl_numa_balancing_scan_delay; |
cbee9f88 | 2240 | p->numa_work.next = &p->numa_work; |
44dba3d5 | 2241 | p->numa_faults = NULL; |
7e2703e6 RR |
2242 | p->last_task_numa_placement = 0; |
2243 | p->last_sum_exec_runtime = 0; | |
8c8a743c | 2244 | |
8c8a743c | 2245 | p->numa_group = NULL; |
cbee9f88 | 2246 | #endif /* CONFIG_NUMA_BALANCING */ |
dd41f596 IM |
2247 | } |
2248 | ||
2a595721 SD |
2249 | DEFINE_STATIC_KEY_FALSE(sched_numa_balancing); |
2250 | ||
1a687c2e | 2251 | #ifdef CONFIG_NUMA_BALANCING |
c3b9bc5b | 2252 | |
1a687c2e MG |
2253 | void set_numabalancing_state(bool enabled) |
2254 | { | |
2255 | if (enabled) | |
2a595721 | 2256 | static_branch_enable(&sched_numa_balancing); |
1a687c2e | 2257 | else |
2a595721 | 2258 | static_branch_disable(&sched_numa_balancing); |
1a687c2e | 2259 | } |
54a43d54 AK |
2260 | |
2261 | #ifdef CONFIG_PROC_SYSCTL | |
2262 | int sysctl_numa_balancing(struct ctl_table *table, int write, | |
2263 | void __user *buffer, size_t *lenp, loff_t *ppos) | |
2264 | { | |
2265 | struct ctl_table t; | |
2266 | int err; | |
2a595721 | 2267 | int state = static_branch_likely(&sched_numa_balancing); |
54a43d54 AK |
2268 | |
2269 | if (write && !capable(CAP_SYS_ADMIN)) | |
2270 | return -EPERM; | |
2271 | ||
2272 | t = *table; | |
2273 | t.data = &state; | |
2274 | err = proc_dointvec_minmax(&t, write, buffer, lenp, ppos); | |
2275 | if (err < 0) | |
2276 | return err; | |
2277 | if (write) | |
2278 | set_numabalancing_state(state); | |
2279 | return err; | |
2280 | } | |
2281 | #endif | |
2282 | #endif | |
dd41f596 IM |
2283 | |
2284 | /* | |
2285 | * fork()/clone()-time setup: | |
2286 | */ | |
aab03e05 | 2287 | int sched_fork(unsigned long clone_flags, struct task_struct *p) |
dd41f596 | 2288 | { |
0122ec5b | 2289 | unsigned long flags; |
dd41f596 IM |
2290 | int cpu = get_cpu(); |
2291 | ||
5e1576ed | 2292 | __sched_fork(clone_flags, p); |
06b83b5f | 2293 | /* |
0017d735 | 2294 | * We mark the process as running here. This guarantees that |
06b83b5f PZ |
2295 | * nobody will actually run it, and a signal or other external |
2296 | * event cannot wake it up and insert it on the runqueue either. | |
2297 | */ | |
0017d735 | 2298 | p->state = TASK_RUNNING; |
dd41f596 | 2299 | |
c350a04e MG |
2300 | /* |
2301 | * Make sure we do not leak PI boosting priority to the child. | |
2302 | */ | |
2303 | p->prio = current->normal_prio; | |
2304 | ||
b9dc29e7 MG |
2305 | /* |
2306 | * Revert to default priority/policy on fork if requested. | |
2307 | */ | |
2308 | if (unlikely(p->sched_reset_on_fork)) { | |
aab03e05 | 2309 | if (task_has_dl_policy(p) || task_has_rt_policy(p)) { |
b9dc29e7 | 2310 | p->policy = SCHED_NORMAL; |
6c697bdf | 2311 | p->static_prio = NICE_TO_PRIO(0); |
c350a04e MG |
2312 | p->rt_priority = 0; |
2313 | } else if (PRIO_TO_NICE(p->static_prio) < 0) | |
2314 | p->static_prio = NICE_TO_PRIO(0); | |
2315 | ||
2316 | p->prio = p->normal_prio = __normal_prio(p); | |
2317 | set_load_weight(p); | |
6c697bdf | 2318 | |
b9dc29e7 MG |
2319 | /* |
2320 | * We don't need the reset flag anymore after the fork. It has | |
2321 | * fulfilled its duty: | |
2322 | */ | |
2323 | p->sched_reset_on_fork = 0; | |
2324 | } | |
ca94c442 | 2325 | |
aab03e05 DF |
2326 | if (dl_prio(p->prio)) { |
2327 | put_cpu(); | |
2328 | return -EAGAIN; | |
2329 | } else if (rt_prio(p->prio)) { | |
2330 | p->sched_class = &rt_sched_class; | |
2331 | } else { | |
2ddbf952 | 2332 | p->sched_class = &fair_sched_class; |
aab03e05 | 2333 | } |
b29739f9 | 2334 | |
cd29fe6f PZ |
2335 | if (p->sched_class->task_fork) |
2336 | p->sched_class->task_fork(p); | |
2337 | ||
86951599 PZ |
2338 | /* |
2339 | * The child is not yet in the pid-hash so no cgroup attach races, | |
2340 | * and the cgroup is pinned to this child due to cgroup_fork() | |
2341 | * is ran before sched_fork(). | |
2342 | * | |
2343 | * Silence PROVE_RCU. | |
2344 | */ | |
0122ec5b | 2345 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
5f3edc1b | 2346 | set_task_cpu(p, cpu); |
0122ec5b | 2347 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
5f3edc1b | 2348 | |
f6db8347 | 2349 | #ifdef CONFIG_SCHED_INFO |
dd41f596 | 2350 | if (likely(sched_info_on())) |
52f17b6c | 2351 | memset(&p->sched_info, 0, sizeof(p->sched_info)); |
1da177e4 | 2352 | #endif |
3ca7a440 PZ |
2353 | #if defined(CONFIG_SMP) |
2354 | p->on_cpu = 0; | |
4866cde0 | 2355 | #endif |
01028747 | 2356 | init_task_preempt_count(p); |
806c09a7 | 2357 | #ifdef CONFIG_SMP |
917b627d | 2358 | plist_node_init(&p->pushable_tasks, MAX_PRIO); |
1baca4ce | 2359 | RB_CLEAR_NODE(&p->pushable_dl_tasks); |
806c09a7 | 2360 | #endif |
917b627d | 2361 | |
476d139c | 2362 | put_cpu(); |
aab03e05 | 2363 | return 0; |
1da177e4 LT |
2364 | } |
2365 | ||
332ac17e DF |
2366 | unsigned long to_ratio(u64 period, u64 runtime) |
2367 | { | |
2368 | if (runtime == RUNTIME_INF) | |
2369 | return 1ULL << 20; | |
2370 | ||
2371 | /* | |
2372 | * Doing this here saves a lot of checks in all | |
2373 | * the calling paths, and returning zero seems | |
2374 | * safe for them anyway. | |
2375 | */ | |
2376 | if (period == 0) | |
2377 | return 0; | |
2378 | ||
2379 | return div64_u64(runtime << 20, period); | |
2380 | } | |
2381 | ||
2382 | #ifdef CONFIG_SMP | |
2383 | inline struct dl_bw *dl_bw_of(int i) | |
2384 | { | |
f78f5b90 PM |
2385 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
2386 | "sched RCU must be held"); | |
332ac17e DF |
2387 | return &cpu_rq(i)->rd->dl_bw; |
2388 | } | |
2389 | ||
de212f18 | 2390 | static inline int dl_bw_cpus(int i) |
332ac17e | 2391 | { |
de212f18 PZ |
2392 | struct root_domain *rd = cpu_rq(i)->rd; |
2393 | int cpus = 0; | |
2394 | ||
f78f5b90 PM |
2395 | RCU_LOCKDEP_WARN(!rcu_read_lock_sched_held(), |
2396 | "sched RCU must be held"); | |
de212f18 PZ |
2397 | for_each_cpu_and(i, rd->span, cpu_active_mask) |
2398 | cpus++; | |
2399 | ||
2400 | return cpus; | |
332ac17e DF |
2401 | } |
2402 | #else | |
2403 | inline struct dl_bw *dl_bw_of(int i) | |
2404 | { | |
2405 | return &cpu_rq(i)->dl.dl_bw; | |
2406 | } | |
2407 | ||
de212f18 | 2408 | static inline int dl_bw_cpus(int i) |
332ac17e DF |
2409 | { |
2410 | return 1; | |
2411 | } | |
2412 | #endif | |
2413 | ||
332ac17e DF |
2414 | /* |
2415 | * We must be sure that accepting a new task (or allowing changing the | |
2416 | * parameters of an existing one) is consistent with the bandwidth | |
2417 | * constraints. If yes, this function also accordingly updates the currently | |
2418 | * allocated bandwidth to reflect the new situation. | |
2419 | * | |
2420 | * This function is called while holding p's rq->lock. | |
40767b0d PZ |
2421 | * |
2422 | * XXX we should delay bw change until the task's 0-lag point, see | |
2423 | * __setparam_dl(). | |
332ac17e DF |
2424 | */ |
2425 | static int dl_overflow(struct task_struct *p, int policy, | |
2426 | const struct sched_attr *attr) | |
2427 | { | |
2428 | ||
2429 | struct dl_bw *dl_b = dl_bw_of(task_cpu(p)); | |
4df1638c | 2430 | u64 period = attr->sched_period ?: attr->sched_deadline; |
332ac17e DF |
2431 | u64 runtime = attr->sched_runtime; |
2432 | u64 new_bw = dl_policy(policy) ? to_ratio(period, runtime) : 0; | |
de212f18 | 2433 | int cpus, err = -1; |
332ac17e DF |
2434 | |
2435 | if (new_bw == p->dl.dl_bw) | |
2436 | return 0; | |
2437 | ||
2438 | /* | |
2439 | * Either if a task, enters, leave, or stays -deadline but changes | |
2440 | * its parameters, we may need to update accordingly the total | |
2441 | * allocated bandwidth of the container. | |
2442 | */ | |
2443 | raw_spin_lock(&dl_b->lock); | |
de212f18 | 2444 | cpus = dl_bw_cpus(task_cpu(p)); |
332ac17e DF |
2445 | if (dl_policy(policy) && !task_has_dl_policy(p) && |
2446 | !__dl_overflow(dl_b, cpus, 0, new_bw)) { | |
2447 | __dl_add(dl_b, new_bw); | |
2448 | err = 0; | |
2449 | } else if (dl_policy(policy) && task_has_dl_policy(p) && | |
2450 | !__dl_overflow(dl_b, cpus, p->dl.dl_bw, new_bw)) { | |
2451 | __dl_clear(dl_b, p->dl.dl_bw); | |
2452 | __dl_add(dl_b, new_bw); | |
2453 | err = 0; | |
2454 | } else if (!dl_policy(policy) && task_has_dl_policy(p)) { | |
2455 | __dl_clear(dl_b, p->dl.dl_bw); | |
2456 | err = 0; | |
2457 | } | |
2458 | raw_spin_unlock(&dl_b->lock); | |
2459 | ||
2460 | return err; | |
2461 | } | |
2462 | ||
2463 | extern void init_dl_bw(struct dl_bw *dl_b); | |
2464 | ||
1da177e4 LT |
2465 | /* |
2466 | * wake_up_new_task - wake up a newly created task for the first time. | |
2467 | * | |
2468 | * This function will do some initial scheduler statistics housekeeping | |
2469 | * that must be done for every newly created context, then puts the task | |
2470 | * on the runqueue and wakes it. | |
2471 | */ | |
3e51e3ed | 2472 | void wake_up_new_task(struct task_struct *p) |
1da177e4 LT |
2473 | { |
2474 | unsigned long flags; | |
dd41f596 | 2475 | struct rq *rq; |
fabf318e | 2476 | |
ab2515c4 | 2477 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
98d8fd81 MR |
2478 | /* Initialize new task's runnable average */ |
2479 | init_entity_runnable_average(&p->se); | |
fabf318e PZ |
2480 | #ifdef CONFIG_SMP |
2481 | /* | |
2482 | * Fork balancing, do it here and not earlier because: | |
2483 | * - cpus_allowed can change in the fork path | |
2484 | * - any previously selected cpu might disappear through hotplug | |
fabf318e | 2485 | */ |
ac66f547 | 2486 | set_task_cpu(p, select_task_rq(p, task_cpu(p), SD_BALANCE_FORK, 0)); |
0017d735 PZ |
2487 | #endif |
2488 | ||
ab2515c4 | 2489 | rq = __task_rq_lock(p); |
cd29fe6f | 2490 | activate_task(rq, p, 0); |
da0c1e65 | 2491 | p->on_rq = TASK_ON_RQ_QUEUED; |
fbd705a0 | 2492 | trace_sched_wakeup_new(p); |
a7558e01 | 2493 | check_preempt_curr(rq, p, WF_FORK); |
9a897c5a | 2494 | #ifdef CONFIG_SMP |
0aaafaab PZ |
2495 | if (p->sched_class->task_woken) { |
2496 | /* | |
2497 | * Nothing relies on rq->lock after this, so its fine to | |
2498 | * drop it. | |
2499 | */ | |
2500 | lockdep_unpin_lock(&rq->lock); | |
efbbd05a | 2501 | p->sched_class->task_woken(rq, p); |
0aaafaab PZ |
2502 | lockdep_pin_lock(&rq->lock); |
2503 | } | |
9a897c5a | 2504 | #endif |
0122ec5b | 2505 | task_rq_unlock(rq, p, &flags); |
1da177e4 LT |
2506 | } |
2507 | ||
e107be36 AK |
2508 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
2509 | ||
1cde2930 PZ |
2510 | static struct static_key preempt_notifier_key = STATIC_KEY_INIT_FALSE; |
2511 | ||
2ecd9d29 PZ |
2512 | void preempt_notifier_inc(void) |
2513 | { | |
2514 | static_key_slow_inc(&preempt_notifier_key); | |
2515 | } | |
2516 | EXPORT_SYMBOL_GPL(preempt_notifier_inc); | |
2517 | ||
2518 | void preempt_notifier_dec(void) | |
2519 | { | |
2520 | static_key_slow_dec(&preempt_notifier_key); | |
2521 | } | |
2522 | EXPORT_SYMBOL_GPL(preempt_notifier_dec); | |
2523 | ||
e107be36 | 2524 | /** |
80dd99b3 | 2525 | * preempt_notifier_register - tell me when current is being preempted & rescheduled |
421cee29 | 2526 | * @notifier: notifier struct to register |
e107be36 AK |
2527 | */ |
2528 | void preempt_notifier_register(struct preempt_notifier *notifier) | |
2529 | { | |
2ecd9d29 PZ |
2530 | if (!static_key_false(&preempt_notifier_key)) |
2531 | WARN(1, "registering preempt_notifier while notifiers disabled\n"); | |
2532 | ||
e107be36 AK |
2533 | hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
2534 | } | |
2535 | EXPORT_SYMBOL_GPL(preempt_notifier_register); | |
2536 | ||
2537 | /** | |
2538 | * preempt_notifier_unregister - no longer interested in preemption notifications | |
421cee29 | 2539 | * @notifier: notifier struct to unregister |
e107be36 | 2540 | * |
d84525a8 | 2541 | * This is *not* safe to call from within a preemption notifier. |
e107be36 AK |
2542 | */ |
2543 | void preempt_notifier_unregister(struct preempt_notifier *notifier) | |
2544 | { | |
2545 | hlist_del(¬ifier->link); | |
2546 | } | |
2547 | EXPORT_SYMBOL_GPL(preempt_notifier_unregister); | |
2548 | ||
1cde2930 | 2549 | static void __fire_sched_in_preempt_notifiers(struct task_struct *curr) |
e107be36 AK |
2550 | { |
2551 | struct preempt_notifier *notifier; | |
e107be36 | 2552 | |
b67bfe0d | 2553 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
2554 | notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
2555 | } | |
2556 | ||
1cde2930 PZ |
2557 | static __always_inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
2558 | { | |
2559 | if (static_key_false(&preempt_notifier_key)) | |
2560 | __fire_sched_in_preempt_notifiers(curr); | |
2561 | } | |
2562 | ||
e107be36 | 2563 | static void |
1cde2930 PZ |
2564 | __fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2565 | struct task_struct *next) | |
e107be36 AK |
2566 | { |
2567 | struct preempt_notifier *notifier; | |
e107be36 | 2568 | |
b67bfe0d | 2569 | hlist_for_each_entry(notifier, &curr->preempt_notifiers, link) |
e107be36 AK |
2570 | notifier->ops->sched_out(notifier, next); |
2571 | } | |
2572 | ||
1cde2930 PZ |
2573 | static __always_inline void |
2574 | fire_sched_out_preempt_notifiers(struct task_struct *curr, | |
2575 | struct task_struct *next) | |
2576 | { | |
2577 | if (static_key_false(&preempt_notifier_key)) | |
2578 | __fire_sched_out_preempt_notifiers(curr, next); | |
2579 | } | |
2580 | ||
6d6bc0ad | 2581 | #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 | 2582 | |
1cde2930 | 2583 | static inline void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
e107be36 AK |
2584 | { |
2585 | } | |
2586 | ||
1cde2930 | 2587 | static inline void |
e107be36 AK |
2588 | fire_sched_out_preempt_notifiers(struct task_struct *curr, |
2589 | struct task_struct *next) | |
2590 | { | |
2591 | } | |
2592 | ||
6d6bc0ad | 2593 | #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
e107be36 | 2594 | |
4866cde0 NP |
2595 | /** |
2596 | * prepare_task_switch - prepare to switch tasks | |
2597 | * @rq: the runqueue preparing to switch | |
421cee29 | 2598 | * @prev: the current task that is being switched out |
4866cde0 NP |
2599 | * @next: the task we are going to switch to. |
2600 | * | |
2601 | * This is called with the rq lock held and interrupts off. It must | |
2602 | * be paired with a subsequent finish_task_switch after the context | |
2603 | * switch. | |
2604 | * | |
2605 | * prepare_task_switch sets up locking and calls architecture specific | |
2606 | * hooks. | |
2607 | */ | |
e107be36 AK |
2608 | static inline void |
2609 | prepare_task_switch(struct rq *rq, struct task_struct *prev, | |
2610 | struct task_struct *next) | |
4866cde0 | 2611 | { |
43148951 | 2612 | sched_info_switch(rq, prev, next); |
fe4b04fa | 2613 | perf_event_task_sched_out(prev, next); |
e107be36 | 2614 | fire_sched_out_preempt_notifiers(prev, next); |
4866cde0 NP |
2615 | prepare_lock_switch(rq, next); |
2616 | prepare_arch_switch(next); | |
2617 | } | |
2618 | ||
1da177e4 LT |
2619 | /** |
2620 | * finish_task_switch - clean up after a task-switch | |
2621 | * @prev: the thread we just switched away from. | |
2622 | * | |
4866cde0 NP |
2623 | * finish_task_switch must be called after the context switch, paired |
2624 | * with a prepare_task_switch call before the context switch. | |
2625 | * finish_task_switch will reconcile locking set up by prepare_task_switch, | |
2626 | * and do any other architecture-specific cleanup actions. | |
1da177e4 LT |
2627 | * |
2628 | * Note that we may have delayed dropping an mm in context_switch(). If | |
41a2d6cf | 2629 | * so, we finish that here outside of the runqueue lock. (Doing it |
1da177e4 LT |
2630 | * with the lock held can cause deadlocks; see schedule() for |
2631 | * details.) | |
dfa50b60 ON |
2632 | * |
2633 | * The context switch have flipped the stack from under us and restored the | |
2634 | * local variables which were saved when this task called schedule() in the | |
2635 | * past. prev == current is still correct but we need to recalculate this_rq | |
2636 | * because prev may have moved to another CPU. | |
1da177e4 | 2637 | */ |
dfa50b60 | 2638 | static struct rq *finish_task_switch(struct task_struct *prev) |
1da177e4 LT |
2639 | __releases(rq->lock) |
2640 | { | |
dfa50b60 | 2641 | struct rq *rq = this_rq(); |
1da177e4 | 2642 | struct mm_struct *mm = rq->prev_mm; |
55a101f8 | 2643 | long prev_state; |
1da177e4 | 2644 | |
609ca066 PZ |
2645 | /* |
2646 | * The previous task will have left us with a preempt_count of 2 | |
2647 | * because it left us after: | |
2648 | * | |
2649 | * schedule() | |
2650 | * preempt_disable(); // 1 | |
2651 | * __schedule() | |
2652 | * raw_spin_lock_irq(&rq->lock) // 2 | |
2653 | * | |
2654 | * Also, see FORK_PREEMPT_COUNT. | |
2655 | */ | |
e2bf1c4b PZ |
2656 | if (WARN_ONCE(preempt_count() != 2*PREEMPT_DISABLE_OFFSET, |
2657 | "corrupted preempt_count: %s/%d/0x%x\n", | |
2658 | current->comm, current->pid, preempt_count())) | |
2659 | preempt_count_set(FORK_PREEMPT_COUNT); | |
609ca066 | 2660 | |
1da177e4 LT |
2661 | rq->prev_mm = NULL; |
2662 | ||
2663 | /* | |
2664 | * A task struct has one reference for the use as "current". | |
c394cc9f | 2665 | * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
55a101f8 ON |
2666 | * schedule one last time. The schedule call will never return, and |
2667 | * the scheduled task must drop that reference. | |
95913d97 PZ |
2668 | * |
2669 | * We must observe prev->state before clearing prev->on_cpu (in | |
2670 | * finish_lock_switch), otherwise a concurrent wakeup can get prev | |
2671 | * running on another CPU and we could rave with its RUNNING -> DEAD | |
2672 | * transition, resulting in a double drop. | |
1da177e4 | 2673 | */ |
55a101f8 | 2674 | prev_state = prev->state; |
bf9fae9f | 2675 | vtime_task_switch(prev); |
a8d757ef | 2676 | perf_event_task_sched_in(prev, current); |
4866cde0 | 2677 | finish_lock_switch(rq, prev); |
01f23e16 | 2678 | finish_arch_post_lock_switch(); |
e8fa1362 | 2679 | |
e107be36 | 2680 | fire_sched_in_preempt_notifiers(current); |
1da177e4 LT |
2681 | if (mm) |
2682 | mmdrop(mm); | |
c394cc9f | 2683 | if (unlikely(prev_state == TASK_DEAD)) { |
e6c390f2 DF |
2684 | if (prev->sched_class->task_dead) |
2685 | prev->sched_class->task_dead(prev); | |
2686 | ||
c6fd91f0 | 2687 | /* |
2688 | * Remove function-return probe instances associated with this | |
2689 | * task and put them back on the free list. | |
9761eea8 | 2690 | */ |
c6fd91f0 | 2691 | kprobe_flush_task(prev); |
1da177e4 | 2692 | put_task_struct(prev); |
c6fd91f0 | 2693 | } |
99e5ada9 | 2694 | |
de734f89 | 2695 | tick_nohz_task_switch(); |
dfa50b60 | 2696 | return rq; |
1da177e4 LT |
2697 | } |
2698 | ||
3f029d3c GH |
2699 | #ifdef CONFIG_SMP |
2700 | ||
3f029d3c | 2701 | /* rq->lock is NOT held, but preemption is disabled */ |
e3fca9e7 | 2702 | static void __balance_callback(struct rq *rq) |
3f029d3c | 2703 | { |
e3fca9e7 PZ |
2704 | struct callback_head *head, *next; |
2705 | void (*func)(struct rq *rq); | |
2706 | unsigned long flags; | |
3f029d3c | 2707 | |
e3fca9e7 PZ |
2708 | raw_spin_lock_irqsave(&rq->lock, flags); |
2709 | head = rq->balance_callback; | |
2710 | rq->balance_callback = NULL; | |
2711 | while (head) { | |
2712 | func = (void (*)(struct rq *))head->func; | |
2713 | next = head->next; | |
2714 | head->next = NULL; | |
2715 | head = next; | |
3f029d3c | 2716 | |
e3fca9e7 | 2717 | func(rq); |
3f029d3c | 2718 | } |
e3fca9e7 PZ |
2719 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
2720 | } | |
2721 | ||
2722 | static inline void balance_callback(struct rq *rq) | |
2723 | { | |
2724 | if (unlikely(rq->balance_callback)) | |
2725 | __balance_callback(rq); | |
3f029d3c GH |
2726 | } |
2727 | ||
2728 | #else | |
da19ab51 | 2729 | |
e3fca9e7 | 2730 | static inline void balance_callback(struct rq *rq) |
3f029d3c | 2731 | { |
1da177e4 LT |
2732 | } |
2733 | ||
3f029d3c GH |
2734 | #endif |
2735 | ||
1da177e4 LT |
2736 | /** |
2737 | * schedule_tail - first thing a freshly forked thread must call. | |
2738 | * @prev: the thread we just switched away from. | |
2739 | */ | |
722a9f92 | 2740 | asmlinkage __visible void schedule_tail(struct task_struct *prev) |
1da177e4 LT |
2741 | __releases(rq->lock) |
2742 | { | |
1a43a14a | 2743 | struct rq *rq; |
da19ab51 | 2744 | |
609ca066 PZ |
2745 | /* |
2746 | * New tasks start with FORK_PREEMPT_COUNT, see there and | |
2747 | * finish_task_switch() for details. | |
2748 | * | |
2749 | * finish_task_switch() will drop rq->lock() and lower preempt_count | |
2750 | * and the preempt_enable() will end up enabling preemption (on | |
2751 | * PREEMPT_COUNT kernels). | |
2752 | */ | |
2753 | ||
dfa50b60 | 2754 | rq = finish_task_switch(prev); |
e3fca9e7 | 2755 | balance_callback(rq); |
1a43a14a | 2756 | preempt_enable(); |
70b97a7f | 2757 | |
1da177e4 | 2758 | if (current->set_child_tid) |
b488893a | 2759 | put_user(task_pid_vnr(current), current->set_child_tid); |
1da177e4 LT |
2760 | } |
2761 | ||
2762 | /* | |
dfa50b60 | 2763 | * context_switch - switch to the new MM and the new thread's register state. |
1da177e4 | 2764 | */ |
dfa50b60 | 2765 | static inline struct rq * |
70b97a7f | 2766 | context_switch(struct rq *rq, struct task_struct *prev, |
36c8b586 | 2767 | struct task_struct *next) |
1da177e4 | 2768 | { |
dd41f596 | 2769 | struct mm_struct *mm, *oldmm; |
1da177e4 | 2770 | |
e107be36 | 2771 | prepare_task_switch(rq, prev, next); |
fe4b04fa | 2772 | |
dd41f596 IM |
2773 | mm = next->mm; |
2774 | oldmm = prev->active_mm; | |
9226d125 ZA |
2775 | /* |
2776 | * For paravirt, this is coupled with an exit in switch_to to | |
2777 | * combine the page table reload and the switch backend into | |
2778 | * one hypercall. | |
2779 | */ | |
224101ed | 2780 | arch_start_context_switch(prev); |
9226d125 | 2781 | |
31915ab4 | 2782 | if (!mm) { |
1da177e4 LT |
2783 | next->active_mm = oldmm; |
2784 | atomic_inc(&oldmm->mm_count); | |
2785 | enter_lazy_tlb(oldmm, next); | |
2786 | } else | |
2787 | switch_mm(oldmm, mm, next); | |
2788 | ||
31915ab4 | 2789 | if (!prev->mm) { |
1da177e4 | 2790 | prev->active_mm = NULL; |
1da177e4 LT |
2791 | rq->prev_mm = oldmm; |
2792 | } | |
3a5f5e48 IM |
2793 | /* |
2794 | * Since the runqueue lock will be released by the next | |
2795 | * task (which is an invalid locking op but in the case | |
2796 | * of the scheduler it's an obvious special-case), so we | |
2797 | * do an early lockdep release here: | |
2798 | */ | |
cbce1a68 | 2799 | lockdep_unpin_lock(&rq->lock); |
8a25d5de | 2800 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
1da177e4 LT |
2801 | |
2802 | /* Here we just switch the register state and the stack. */ | |
2803 | switch_to(prev, next, prev); | |
dd41f596 | 2804 | barrier(); |
dfa50b60 ON |
2805 | |
2806 | return finish_task_switch(prev); | |
1da177e4 LT |
2807 | } |
2808 | ||
2809 | /* | |
1c3e8264 | 2810 | * nr_running and nr_context_switches: |
1da177e4 LT |
2811 | * |
2812 | * externally visible scheduler statistics: current number of runnable | |
1c3e8264 | 2813 | * threads, total number of context switches performed since bootup. |
1da177e4 LT |
2814 | */ |
2815 | unsigned long nr_running(void) | |
2816 | { | |
2817 | unsigned long i, sum = 0; | |
2818 | ||
2819 | for_each_online_cpu(i) | |
2820 | sum += cpu_rq(i)->nr_running; | |
2821 | ||
2822 | return sum; | |
f711f609 | 2823 | } |
1da177e4 | 2824 | |
2ee507c4 TC |
2825 | /* |
2826 | * Check if only the current task is running on the cpu. | |
00cc1633 DD |
2827 | * |
2828 | * Caution: this function does not check that the caller has disabled | |
2829 | * preemption, thus the result might have a time-of-check-to-time-of-use | |
2830 | * race. The caller is responsible to use it correctly, for example: | |
2831 | * | |
2832 | * - from a non-preemptable section (of course) | |
2833 | * | |
2834 | * - from a thread that is bound to a single CPU | |
2835 | * | |
2836 | * - in a loop with very short iterations (e.g. a polling loop) | |
2ee507c4 TC |
2837 | */ |
2838 | bool single_task_running(void) | |
2839 | { | |
00cc1633 | 2840 | return raw_rq()->nr_running == 1; |
2ee507c4 TC |
2841 | } |
2842 | EXPORT_SYMBOL(single_task_running); | |
2843 | ||
1da177e4 | 2844 | unsigned long long nr_context_switches(void) |
46cb4b7c | 2845 | { |
cc94abfc SR |
2846 | int i; |
2847 | unsigned long long sum = 0; | |
46cb4b7c | 2848 | |
0a945022 | 2849 | for_each_possible_cpu(i) |
1da177e4 | 2850 | sum += cpu_rq(i)->nr_switches; |
46cb4b7c | 2851 | |
1da177e4 LT |
2852 | return sum; |
2853 | } | |
483b4ee6 | 2854 | |
1da177e4 LT |
2855 | unsigned long nr_iowait(void) |
2856 | { | |
2857 | unsigned long i, sum = 0; | |
483b4ee6 | 2858 | |
0a945022 | 2859 | for_each_possible_cpu(i) |
1da177e4 | 2860 | sum += atomic_read(&cpu_rq(i)->nr_iowait); |
46cb4b7c | 2861 | |
1da177e4 LT |
2862 | return sum; |
2863 | } | |
483b4ee6 | 2864 | |
8c215bd3 | 2865 | unsigned long nr_iowait_cpu(int cpu) |
69d25870 | 2866 | { |
8c215bd3 | 2867 | struct rq *this = cpu_rq(cpu); |
69d25870 AV |
2868 | return atomic_read(&this->nr_iowait); |
2869 | } | |
46cb4b7c | 2870 | |
372ba8cb MG |
2871 | void get_iowait_load(unsigned long *nr_waiters, unsigned long *load) |
2872 | { | |
3289bdb4 PZ |
2873 | struct rq *rq = this_rq(); |
2874 | *nr_waiters = atomic_read(&rq->nr_iowait); | |
2875 | *load = rq->load.weight; | |
372ba8cb MG |
2876 | } |
2877 | ||
dd41f596 | 2878 | #ifdef CONFIG_SMP |
8a0be9ef | 2879 | |
46cb4b7c | 2880 | /* |
38022906 PZ |
2881 | * sched_exec - execve() is a valuable balancing opportunity, because at |
2882 | * this point the task has the smallest effective memory and cache footprint. | |
46cb4b7c | 2883 | */ |
38022906 | 2884 | void sched_exec(void) |
46cb4b7c | 2885 | { |
38022906 | 2886 | struct task_struct *p = current; |
1da177e4 | 2887 | unsigned long flags; |
0017d735 | 2888 | int dest_cpu; |
46cb4b7c | 2889 | |
8f42ced9 | 2890 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
ac66f547 | 2891 | dest_cpu = p->sched_class->select_task_rq(p, task_cpu(p), SD_BALANCE_EXEC, 0); |
0017d735 PZ |
2892 | if (dest_cpu == smp_processor_id()) |
2893 | goto unlock; | |
38022906 | 2894 | |
8f42ced9 | 2895 | if (likely(cpu_active(dest_cpu))) { |
969c7921 | 2896 | struct migration_arg arg = { p, dest_cpu }; |
46cb4b7c | 2897 | |
8f42ced9 PZ |
2898 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
2899 | stop_one_cpu(task_cpu(p), migration_cpu_stop, &arg); | |
1da177e4 LT |
2900 | return; |
2901 | } | |
0017d735 | 2902 | unlock: |
8f42ced9 | 2903 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 | 2904 | } |
dd41f596 | 2905 | |
1da177e4 LT |
2906 | #endif |
2907 | ||
1da177e4 | 2908 | DEFINE_PER_CPU(struct kernel_stat, kstat); |
3292beb3 | 2909 | DEFINE_PER_CPU(struct kernel_cpustat, kernel_cpustat); |
1da177e4 LT |
2910 | |
2911 | EXPORT_PER_CPU_SYMBOL(kstat); | |
3292beb3 | 2912 | EXPORT_PER_CPU_SYMBOL(kernel_cpustat); |
1da177e4 | 2913 | |
c5f8d995 HS |
2914 | /* |
2915 | * Return accounted runtime for the task. | |
2916 | * In case the task is currently running, return the runtime plus current's | |
2917 | * pending runtime that have not been accounted yet. | |
2918 | */ | |
2919 | unsigned long long task_sched_runtime(struct task_struct *p) | |
2920 | { | |
2921 | unsigned long flags; | |
2922 | struct rq *rq; | |
6e998916 | 2923 | u64 ns; |
c5f8d995 | 2924 | |
911b2898 PZ |
2925 | #if defined(CONFIG_64BIT) && defined(CONFIG_SMP) |
2926 | /* | |
2927 | * 64-bit doesn't need locks to atomically read a 64bit value. | |
2928 | * So we have a optimization chance when the task's delta_exec is 0. | |
2929 | * Reading ->on_cpu is racy, but this is ok. | |
2930 | * | |
2931 | * If we race with it leaving cpu, we'll take a lock. So we're correct. | |
2932 | * If we race with it entering cpu, unaccounted time is 0. This is | |
2933 | * indistinguishable from the read occurring a few cycles earlier. | |
4036ac15 MG |
2934 | * If we see ->on_cpu without ->on_rq, the task is leaving, and has |
2935 | * been accounted, so we're correct here as well. | |
911b2898 | 2936 | */ |
da0c1e65 | 2937 | if (!p->on_cpu || !task_on_rq_queued(p)) |
911b2898 PZ |
2938 | return p->se.sum_exec_runtime; |
2939 | #endif | |
2940 | ||
c5f8d995 | 2941 | rq = task_rq_lock(p, &flags); |
6e998916 SG |
2942 | /* |
2943 | * Must be ->curr _and_ ->on_rq. If dequeued, we would | |
2944 | * project cycles that may never be accounted to this | |
2945 | * thread, breaking clock_gettime(). | |
2946 | */ | |
2947 | if (task_current(rq, p) && task_on_rq_queued(p)) { | |
2948 | update_rq_clock(rq); | |
2949 | p->sched_class->update_curr(rq); | |
2950 | } | |
2951 | ns = p->se.sum_exec_runtime; | |
0122ec5b | 2952 | task_rq_unlock(rq, p, &flags); |
c5f8d995 HS |
2953 | |
2954 | return ns; | |
2955 | } | |
48f24c4d | 2956 | |
7835b98b CL |
2957 | /* |
2958 | * This function gets called by the timer code, with HZ frequency. | |
2959 | * We call it with interrupts disabled. | |
7835b98b CL |
2960 | */ |
2961 | void scheduler_tick(void) | |
2962 | { | |
7835b98b CL |
2963 | int cpu = smp_processor_id(); |
2964 | struct rq *rq = cpu_rq(cpu); | |
dd41f596 | 2965 | struct task_struct *curr = rq->curr; |
3e51f33f PZ |
2966 | |
2967 | sched_clock_tick(); | |
dd41f596 | 2968 | |
05fa785c | 2969 | raw_spin_lock(&rq->lock); |
3e51f33f | 2970 | update_rq_clock(rq); |
fa85ae24 | 2971 | curr->sched_class->task_tick(rq, curr, 0); |
83dfd523 | 2972 | update_cpu_load_active(rq); |
3289bdb4 | 2973 | calc_global_load_tick(rq); |
05fa785c | 2974 | raw_spin_unlock(&rq->lock); |
7835b98b | 2975 | |
e9d2b064 | 2976 | perf_event_task_tick(); |
e220d2dc | 2977 | |
e418e1c2 | 2978 | #ifdef CONFIG_SMP |
6eb57e0d | 2979 | rq->idle_balance = idle_cpu(cpu); |
7caff66f | 2980 | trigger_load_balance(rq); |
e418e1c2 | 2981 | #endif |
265f22a9 | 2982 | rq_last_tick_reset(rq); |
1da177e4 LT |
2983 | } |
2984 | ||
265f22a9 FW |
2985 | #ifdef CONFIG_NO_HZ_FULL |
2986 | /** | |
2987 | * scheduler_tick_max_deferment | |
2988 | * | |
2989 | * Keep at least one tick per second when a single | |
2990 | * active task is running because the scheduler doesn't | |
2991 | * yet completely support full dynticks environment. | |
2992 | * | |
2993 | * This makes sure that uptime, CFS vruntime, load | |
2994 | * balancing, etc... continue to move forward, even | |
2995 | * with a very low granularity. | |
e69f6186 YB |
2996 | * |
2997 | * Return: Maximum deferment in nanoseconds. | |
265f22a9 FW |
2998 | */ |
2999 | u64 scheduler_tick_max_deferment(void) | |
3000 | { | |
3001 | struct rq *rq = this_rq(); | |
316c1608 | 3002 | unsigned long next, now = READ_ONCE(jiffies); |
265f22a9 FW |
3003 | |
3004 | next = rq->last_sched_tick + HZ; | |
3005 | ||
3006 | if (time_before_eq(next, now)) | |
3007 | return 0; | |
3008 | ||
8fe8ff09 | 3009 | return jiffies_to_nsecs(next - now); |
1da177e4 | 3010 | } |
265f22a9 | 3011 | #endif |
1da177e4 | 3012 | |
132380a0 | 3013 | notrace unsigned long get_parent_ip(unsigned long addr) |
6cd8a4bb SR |
3014 | { |
3015 | if (in_lock_functions(addr)) { | |
3016 | addr = CALLER_ADDR2; | |
3017 | if (in_lock_functions(addr)) | |
3018 | addr = CALLER_ADDR3; | |
3019 | } | |
3020 | return addr; | |
3021 | } | |
1da177e4 | 3022 | |
7e49fcce SR |
3023 | #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
3024 | defined(CONFIG_PREEMPT_TRACER)) | |
3025 | ||
edafe3a5 | 3026 | void preempt_count_add(int val) |
1da177e4 | 3027 | { |
6cd8a4bb | 3028 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3029 | /* |
3030 | * Underflow? | |
3031 | */ | |
9a11b49a IM |
3032 | if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
3033 | return; | |
6cd8a4bb | 3034 | #endif |
bdb43806 | 3035 | __preempt_count_add(val); |
6cd8a4bb | 3036 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3037 | /* |
3038 | * Spinlock count overflowing soon? | |
3039 | */ | |
33859f7f MOS |
3040 | DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
3041 | PREEMPT_MASK - 10); | |
6cd8a4bb | 3042 | #endif |
8f47b187 TG |
3043 | if (preempt_count() == val) { |
3044 | unsigned long ip = get_parent_ip(CALLER_ADDR1); | |
3045 | #ifdef CONFIG_DEBUG_PREEMPT | |
3046 | current->preempt_disable_ip = ip; | |
3047 | #endif | |
3048 | trace_preempt_off(CALLER_ADDR0, ip); | |
3049 | } | |
1da177e4 | 3050 | } |
bdb43806 | 3051 | EXPORT_SYMBOL(preempt_count_add); |
edafe3a5 | 3052 | NOKPROBE_SYMBOL(preempt_count_add); |
1da177e4 | 3053 | |
edafe3a5 | 3054 | void preempt_count_sub(int val) |
1da177e4 | 3055 | { |
6cd8a4bb | 3056 | #ifdef CONFIG_DEBUG_PREEMPT |
1da177e4 LT |
3057 | /* |
3058 | * Underflow? | |
3059 | */ | |
01e3eb82 | 3060 | if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
9a11b49a | 3061 | return; |
1da177e4 LT |
3062 | /* |
3063 | * Is the spinlock portion underflowing? | |
3064 | */ | |
9a11b49a IM |
3065 | if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
3066 | !(preempt_count() & PREEMPT_MASK))) | |
3067 | return; | |
6cd8a4bb | 3068 | #endif |
9a11b49a | 3069 | |
6cd8a4bb SR |
3070 | if (preempt_count() == val) |
3071 | trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); | |
bdb43806 | 3072 | __preempt_count_sub(val); |
1da177e4 | 3073 | } |
bdb43806 | 3074 | EXPORT_SYMBOL(preempt_count_sub); |
edafe3a5 | 3075 | NOKPROBE_SYMBOL(preempt_count_sub); |
1da177e4 LT |
3076 | |
3077 | #endif | |
3078 | ||
3079 | /* | |
dd41f596 | 3080 | * Print scheduling while atomic bug: |
1da177e4 | 3081 | */ |
dd41f596 | 3082 | static noinline void __schedule_bug(struct task_struct *prev) |
1da177e4 | 3083 | { |
664dfa65 DJ |
3084 | if (oops_in_progress) |
3085 | return; | |
3086 | ||
3df0fc5b PZ |
3087 | printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
3088 | prev->comm, prev->pid, preempt_count()); | |
838225b4 | 3089 | |
dd41f596 | 3090 | debug_show_held_locks(prev); |
e21f5b15 | 3091 | print_modules(); |
dd41f596 IM |
3092 | if (irqs_disabled()) |
3093 | print_irqtrace_events(prev); | |
8f47b187 TG |
3094 | #ifdef CONFIG_DEBUG_PREEMPT |
3095 | if (in_atomic_preempt_off()) { | |
3096 | pr_err("Preemption disabled at:"); | |
3097 | print_ip_sym(current->preempt_disable_ip); | |
3098 | pr_cont("\n"); | |
3099 | } | |
3100 | #endif | |
6135fc1e | 3101 | dump_stack(); |
373d4d09 | 3102 | add_taint(TAINT_WARN, LOCKDEP_STILL_OK); |
dd41f596 | 3103 | } |
1da177e4 | 3104 | |
dd41f596 IM |
3105 | /* |
3106 | * Various schedule()-time debugging checks and statistics: | |
3107 | */ | |
3108 | static inline void schedule_debug(struct task_struct *prev) | |
3109 | { | |
0d9e2632 | 3110 | #ifdef CONFIG_SCHED_STACK_END_CHECK |
ce03e413 | 3111 | BUG_ON(task_stack_end_corrupted(prev)); |
0d9e2632 | 3112 | #endif |
b99def8b | 3113 | |
1dc0fffc | 3114 | if (unlikely(in_atomic_preempt_off())) { |
dd41f596 | 3115 | __schedule_bug(prev); |
1dc0fffc PZ |
3116 | preempt_count_set(PREEMPT_DISABLED); |
3117 | } | |
b3fbab05 | 3118 | rcu_sleep_check(); |
dd41f596 | 3119 | |
1da177e4 LT |
3120 | profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
3121 | ||
2d72376b | 3122 | schedstat_inc(this_rq(), sched_count); |
dd41f596 IM |
3123 | } |
3124 | ||
3125 | /* | |
3126 | * Pick up the highest-prio task: | |
3127 | */ | |
3128 | static inline struct task_struct * | |
606dba2e | 3129 | pick_next_task(struct rq *rq, struct task_struct *prev) |
dd41f596 | 3130 | { |
37e117c0 | 3131 | const struct sched_class *class = &fair_sched_class; |
dd41f596 | 3132 | struct task_struct *p; |
1da177e4 LT |
3133 | |
3134 | /* | |
dd41f596 IM |
3135 | * Optimization: we know that if all tasks are in |
3136 | * the fair class we can call that function directly: | |
1da177e4 | 3137 | */ |
37e117c0 | 3138 | if (likely(prev->sched_class == class && |
38033c37 | 3139 | rq->nr_running == rq->cfs.h_nr_running)) { |
606dba2e | 3140 | p = fair_sched_class.pick_next_task(rq, prev); |
6ccdc84b PZ |
3141 | if (unlikely(p == RETRY_TASK)) |
3142 | goto again; | |
3143 | ||
3144 | /* assumes fair_sched_class->next == idle_sched_class */ | |
3145 | if (unlikely(!p)) | |
3146 | p = idle_sched_class.pick_next_task(rq, prev); | |
3147 | ||
3148 | return p; | |
1da177e4 LT |
3149 | } |
3150 | ||
37e117c0 | 3151 | again: |
34f971f6 | 3152 | for_each_class(class) { |
606dba2e | 3153 | p = class->pick_next_task(rq, prev); |
37e117c0 PZ |
3154 | if (p) { |
3155 | if (unlikely(p == RETRY_TASK)) | |
3156 | goto again; | |
dd41f596 | 3157 | return p; |
37e117c0 | 3158 | } |
dd41f596 | 3159 | } |
34f971f6 PZ |
3160 | |
3161 | BUG(); /* the idle class will always have a runnable task */ | |
dd41f596 | 3162 | } |
1da177e4 | 3163 | |
dd41f596 | 3164 | /* |
c259e01a | 3165 | * __schedule() is the main scheduler function. |
edde96ea PE |
3166 | * |
3167 | * The main means of driving the scheduler and thus entering this function are: | |
3168 | * | |
3169 | * 1. Explicit blocking: mutex, semaphore, waitqueue, etc. | |
3170 | * | |
3171 | * 2. TIF_NEED_RESCHED flag is checked on interrupt and userspace return | |
3172 | * paths. For example, see arch/x86/entry_64.S. | |
3173 | * | |
3174 | * To drive preemption between tasks, the scheduler sets the flag in timer | |
3175 | * interrupt handler scheduler_tick(). | |
3176 | * | |
3177 | * 3. Wakeups don't really cause entry into schedule(). They add a | |
3178 | * task to the run-queue and that's it. | |
3179 | * | |
3180 | * Now, if the new task added to the run-queue preempts the current | |
3181 | * task, then the wakeup sets TIF_NEED_RESCHED and schedule() gets | |
3182 | * called on the nearest possible occasion: | |
3183 | * | |
3184 | * - If the kernel is preemptible (CONFIG_PREEMPT=y): | |
3185 | * | |
3186 | * - in syscall or exception context, at the next outmost | |
3187 | * preempt_enable(). (this might be as soon as the wake_up()'s | |
3188 | * spin_unlock()!) | |
3189 | * | |
3190 | * - in IRQ context, return from interrupt-handler to | |
3191 | * preemptible context | |
3192 | * | |
3193 | * - If the kernel is not preemptible (CONFIG_PREEMPT is not set) | |
3194 | * then at the next: | |
3195 | * | |
3196 | * - cond_resched() call | |
3197 | * - explicit schedule() call | |
3198 | * - return from syscall or exception to user-space | |
3199 | * - return from interrupt-handler to user-space | |
bfd9b2b5 | 3200 | * |
b30f0e3f | 3201 | * WARNING: must be called with preemption disabled! |
dd41f596 | 3202 | */ |
499d7955 | 3203 | static void __sched notrace __schedule(bool preempt) |
dd41f596 IM |
3204 | { |
3205 | struct task_struct *prev, *next; | |
67ca7bde | 3206 | unsigned long *switch_count; |
dd41f596 | 3207 | struct rq *rq; |
31656519 | 3208 | int cpu; |
dd41f596 | 3209 | |
dd41f596 IM |
3210 | cpu = smp_processor_id(); |
3211 | rq = cpu_rq(cpu); | |
dd41f596 | 3212 | prev = rq->curr; |
dd41f596 | 3213 | |
b99def8b PZ |
3214 | /* |
3215 | * do_exit() calls schedule() with preemption disabled as an exception; | |
3216 | * however we must fix that up, otherwise the next task will see an | |
3217 | * inconsistent (higher) preempt count. | |
3218 | * | |
3219 | * It also avoids the below schedule_debug() test from complaining | |
3220 | * about this. | |
3221 | */ | |
3222 | if (unlikely(prev->state == TASK_DEAD)) | |
3223 | preempt_enable_no_resched_notrace(); | |
3224 | ||
dd41f596 | 3225 | schedule_debug(prev); |
1da177e4 | 3226 | |
31656519 | 3227 | if (sched_feat(HRTICK)) |
f333fdc9 | 3228 | hrtick_clear(rq); |
8f4d37ec | 3229 | |
46a5d164 PM |
3230 | local_irq_disable(); |
3231 | rcu_note_context_switch(); | |
3232 | ||
e0acd0a6 ON |
3233 | /* |
3234 | * Make sure that signal_pending_state()->signal_pending() below | |
3235 | * can't be reordered with __set_current_state(TASK_INTERRUPTIBLE) | |
3236 | * done by the caller to avoid the race with signal_wake_up(). | |
3237 | */ | |
3238 | smp_mb__before_spinlock(); | |
46a5d164 | 3239 | raw_spin_lock(&rq->lock); |
cbce1a68 | 3240 | lockdep_pin_lock(&rq->lock); |
1da177e4 | 3241 | |
9edfbfed PZ |
3242 | rq->clock_skip_update <<= 1; /* promote REQ to ACT */ |
3243 | ||
246d86b5 | 3244 | switch_count = &prev->nivcsw; |
fc13aeba | 3245 | if (!preempt && prev->state) { |
21aa9af0 | 3246 | if (unlikely(signal_pending_state(prev->state, prev))) { |
1da177e4 | 3247 | prev->state = TASK_RUNNING; |
21aa9af0 | 3248 | } else { |
2acca55e PZ |
3249 | deactivate_task(rq, prev, DEQUEUE_SLEEP); |
3250 | prev->on_rq = 0; | |
3251 | ||
21aa9af0 | 3252 | /* |
2acca55e PZ |
3253 | * If a worker went to sleep, notify and ask workqueue |
3254 | * whether it wants to wake up a task to maintain | |
3255 | * concurrency. | |
21aa9af0 TH |
3256 | */ |
3257 | if (prev->flags & PF_WQ_WORKER) { | |
3258 | struct task_struct *to_wakeup; | |
3259 | ||
3260 | to_wakeup = wq_worker_sleeping(prev, cpu); | |
3261 | if (to_wakeup) | |
3262 | try_to_wake_up_local(to_wakeup); | |
3263 | } | |
21aa9af0 | 3264 | } |
dd41f596 | 3265 | switch_count = &prev->nvcsw; |
1da177e4 LT |
3266 | } |
3267 | ||
9edfbfed | 3268 | if (task_on_rq_queued(prev)) |
606dba2e PZ |
3269 | update_rq_clock(rq); |
3270 | ||
3271 | next = pick_next_task(rq, prev); | |
f26f9aff | 3272 | clear_tsk_need_resched(prev); |
f27dde8d | 3273 | clear_preempt_need_resched(); |
9edfbfed | 3274 | rq->clock_skip_update = 0; |
1da177e4 | 3275 | |
1da177e4 | 3276 | if (likely(prev != next)) { |
1da177e4 LT |
3277 | rq->nr_switches++; |
3278 | rq->curr = next; | |
3279 | ++*switch_count; | |
3280 | ||
c73464b1 | 3281 | trace_sched_switch(preempt, prev, next); |
dfa50b60 ON |
3282 | rq = context_switch(rq, prev, next); /* unlocks the rq */ |
3283 | cpu = cpu_of(rq); | |
cbce1a68 PZ |
3284 | } else { |
3285 | lockdep_unpin_lock(&rq->lock); | |
05fa785c | 3286 | raw_spin_unlock_irq(&rq->lock); |
cbce1a68 | 3287 | } |
1da177e4 | 3288 | |
e3fca9e7 | 3289 | balance_callback(rq); |
1da177e4 | 3290 | } |
c259e01a | 3291 | |
9c40cef2 TG |
3292 | static inline void sched_submit_work(struct task_struct *tsk) |
3293 | { | |
3c7d5184 | 3294 | if (!tsk->state || tsk_is_pi_blocked(tsk)) |
9c40cef2 TG |
3295 | return; |
3296 | /* | |
3297 | * If we are going to sleep and we have plugged IO queued, | |
3298 | * make sure to submit it to avoid deadlocks. | |
3299 | */ | |
3300 | if (blk_needs_flush_plug(tsk)) | |
3301 | blk_schedule_flush_plug(tsk); | |
3302 | } | |
3303 | ||
722a9f92 | 3304 | asmlinkage __visible void __sched schedule(void) |
c259e01a | 3305 | { |
9c40cef2 TG |
3306 | struct task_struct *tsk = current; |
3307 | ||
3308 | sched_submit_work(tsk); | |
bfd9b2b5 | 3309 | do { |
b30f0e3f | 3310 | preempt_disable(); |
fc13aeba | 3311 | __schedule(false); |
b30f0e3f | 3312 | sched_preempt_enable_no_resched(); |
bfd9b2b5 | 3313 | } while (need_resched()); |
c259e01a | 3314 | } |
1da177e4 LT |
3315 | EXPORT_SYMBOL(schedule); |
3316 | ||
91d1aa43 | 3317 | #ifdef CONFIG_CONTEXT_TRACKING |
722a9f92 | 3318 | asmlinkage __visible void __sched schedule_user(void) |
20ab65e3 FW |
3319 | { |
3320 | /* | |
3321 | * If we come here after a random call to set_need_resched(), | |
3322 | * or we have been woken up remotely but the IPI has not yet arrived, | |
3323 | * we haven't yet exited the RCU idle mode. Do it here manually until | |
3324 | * we find a better solution. | |
7cc78f8f AL |
3325 | * |
3326 | * NB: There are buggy callers of this function. Ideally we | |
c467ea76 | 3327 | * should warn if prev_state != CONTEXT_USER, but that will trigger |
7cc78f8f | 3328 | * too frequently to make sense yet. |
20ab65e3 | 3329 | */ |
7cc78f8f | 3330 | enum ctx_state prev_state = exception_enter(); |
20ab65e3 | 3331 | schedule(); |
7cc78f8f | 3332 | exception_exit(prev_state); |
20ab65e3 FW |
3333 | } |
3334 | #endif | |
3335 | ||
c5491ea7 TG |
3336 | /** |
3337 | * schedule_preempt_disabled - called with preemption disabled | |
3338 | * | |
3339 | * Returns with preemption disabled. Note: preempt_count must be 1 | |
3340 | */ | |
3341 | void __sched schedule_preempt_disabled(void) | |
3342 | { | |
ba74c144 | 3343 | sched_preempt_enable_no_resched(); |
c5491ea7 TG |
3344 | schedule(); |
3345 | preempt_disable(); | |
3346 | } | |
3347 | ||
06b1f808 | 3348 | static void __sched notrace preempt_schedule_common(void) |
a18b5d01 FW |
3349 | { |
3350 | do { | |
499d7955 | 3351 | preempt_disable_notrace(); |
fc13aeba | 3352 | __schedule(true); |
499d7955 | 3353 | preempt_enable_no_resched_notrace(); |
a18b5d01 FW |
3354 | |
3355 | /* | |
3356 | * Check again in case we missed a preemption opportunity | |
3357 | * between schedule and now. | |
3358 | */ | |
a18b5d01 FW |
3359 | } while (need_resched()); |
3360 | } | |
3361 | ||
1da177e4 LT |
3362 | #ifdef CONFIG_PREEMPT |
3363 | /* | |
2ed6e34f | 3364 | * this is the entry point to schedule() from in-kernel preemption |
41a2d6cf | 3365 | * off of preempt_enable. Kernel preemptions off return from interrupt |
1da177e4 LT |
3366 | * occur there and call schedule directly. |
3367 | */ | |
722a9f92 | 3368 | asmlinkage __visible void __sched notrace preempt_schedule(void) |
1da177e4 | 3369 | { |
1da177e4 LT |
3370 | /* |
3371 | * If there is a non-zero preempt_count or interrupts are disabled, | |
41a2d6cf | 3372 | * we do not want to preempt the current task. Just return.. |
1da177e4 | 3373 | */ |
fbb00b56 | 3374 | if (likely(!preemptible())) |
1da177e4 LT |
3375 | return; |
3376 | ||
a18b5d01 | 3377 | preempt_schedule_common(); |
1da177e4 | 3378 | } |
376e2424 | 3379 | NOKPROBE_SYMBOL(preempt_schedule); |
1da177e4 | 3380 | EXPORT_SYMBOL(preempt_schedule); |
009f60e2 | 3381 | |
009f60e2 | 3382 | /** |
4eaca0a8 | 3383 | * preempt_schedule_notrace - preempt_schedule called by tracing |
009f60e2 ON |
3384 | * |
3385 | * The tracing infrastructure uses preempt_enable_notrace to prevent | |
3386 | * recursion and tracing preempt enabling caused by the tracing | |
3387 | * infrastructure itself. But as tracing can happen in areas coming | |
3388 | * from userspace or just about to enter userspace, a preempt enable | |
3389 | * can occur before user_exit() is called. This will cause the scheduler | |
3390 | * to be called when the system is still in usermode. | |
3391 | * | |
3392 | * To prevent this, the preempt_enable_notrace will use this function | |
3393 | * instead of preempt_schedule() to exit user context if needed before | |
3394 | * calling the scheduler. | |
3395 | */ | |
4eaca0a8 | 3396 | asmlinkage __visible void __sched notrace preempt_schedule_notrace(void) |
009f60e2 ON |
3397 | { |
3398 | enum ctx_state prev_ctx; | |
3399 | ||
3400 | if (likely(!preemptible())) | |
3401 | return; | |
3402 | ||
3403 | do { | |
3d8f74dd | 3404 | preempt_disable_notrace(); |
009f60e2 ON |
3405 | /* |
3406 | * Needs preempt disabled in case user_exit() is traced | |
3407 | * and the tracer calls preempt_enable_notrace() causing | |
3408 | * an infinite recursion. | |
3409 | */ | |
3410 | prev_ctx = exception_enter(); | |
fc13aeba | 3411 | __schedule(true); |
009f60e2 ON |
3412 | exception_exit(prev_ctx); |
3413 | ||
3d8f74dd | 3414 | preempt_enable_no_resched_notrace(); |
009f60e2 ON |
3415 | } while (need_resched()); |
3416 | } | |
4eaca0a8 | 3417 | EXPORT_SYMBOL_GPL(preempt_schedule_notrace); |
009f60e2 | 3418 | |
32e475d7 | 3419 | #endif /* CONFIG_PREEMPT */ |
1da177e4 LT |
3420 | |
3421 | /* | |
2ed6e34f | 3422 | * this is the entry point to schedule() from kernel preemption |
1da177e4 LT |
3423 | * off of irq context. |
3424 | * Note, that this is called and return with irqs disabled. This will | |
3425 | * protect us against recursive calling from irq. | |
3426 | */ | |
722a9f92 | 3427 | asmlinkage __visible void __sched preempt_schedule_irq(void) |
1da177e4 | 3428 | { |
b22366cd | 3429 | enum ctx_state prev_state; |
6478d880 | 3430 | |
2ed6e34f | 3431 | /* Catch callers which need to be fixed */ |
f27dde8d | 3432 | BUG_ON(preempt_count() || !irqs_disabled()); |
1da177e4 | 3433 | |
b22366cd FW |
3434 | prev_state = exception_enter(); |
3435 | ||
3a5c359a | 3436 | do { |
3d8f74dd | 3437 | preempt_disable(); |
3a5c359a | 3438 | local_irq_enable(); |
fc13aeba | 3439 | __schedule(true); |
3a5c359a | 3440 | local_irq_disable(); |
3d8f74dd | 3441 | sched_preempt_enable_no_resched(); |
5ed0cec0 | 3442 | } while (need_resched()); |
b22366cd FW |
3443 | |
3444 | exception_exit(prev_state); | |
1da177e4 LT |
3445 | } |
3446 | ||
63859d4f | 3447 | int default_wake_function(wait_queue_t *curr, unsigned mode, int wake_flags, |
95cdf3b7 | 3448 | void *key) |
1da177e4 | 3449 | { |
63859d4f | 3450 | return try_to_wake_up(curr->private, mode, wake_flags); |
1da177e4 | 3451 | } |
1da177e4 LT |
3452 | EXPORT_SYMBOL(default_wake_function); |
3453 | ||
b29739f9 IM |
3454 | #ifdef CONFIG_RT_MUTEXES |
3455 | ||
3456 | /* | |
3457 | * rt_mutex_setprio - set the current priority of a task | |
3458 | * @p: task | |
3459 | * @prio: prio value (kernel-internal form) | |
3460 | * | |
3461 | * This function changes the 'effective' priority of a task. It does | |
3462 | * not touch ->normal_prio like __setscheduler(). | |
3463 | * | |
c365c292 TG |
3464 | * Used by the rt_mutex code to implement priority inheritance |
3465 | * logic. Call site only calls if the priority of the task changed. | |
b29739f9 | 3466 | */ |
36c8b586 | 3467 | void rt_mutex_setprio(struct task_struct *p, int prio) |
b29739f9 | 3468 | { |
1de64443 | 3469 | int oldprio, queued, running, enqueue_flag = ENQUEUE_RESTORE; |
70b97a7f | 3470 | struct rq *rq; |
83ab0aa0 | 3471 | const struct sched_class *prev_class; |
b29739f9 | 3472 | |
aab03e05 | 3473 | BUG_ON(prio > MAX_PRIO); |
b29739f9 | 3474 | |
0122ec5b | 3475 | rq = __task_rq_lock(p); |
b29739f9 | 3476 | |
1c4dd99b TG |
3477 | /* |
3478 | * Idle task boosting is a nono in general. There is one | |
3479 | * exception, when PREEMPT_RT and NOHZ is active: | |
3480 | * | |
3481 | * The idle task calls get_next_timer_interrupt() and holds | |
3482 | * the timer wheel base->lock on the CPU and another CPU wants | |
3483 | * to access the timer (probably to cancel it). We can safely | |
3484 | * ignore the boosting request, as the idle CPU runs this code | |
3485 | * with interrupts disabled and will complete the lock | |
3486 | * protected section without being interrupted. So there is no | |
3487 | * real need to boost. | |
3488 | */ | |
3489 | if (unlikely(p == rq->idle)) { | |
3490 | WARN_ON(p != rq->curr); | |
3491 | WARN_ON(p->pi_blocked_on); | |
3492 | goto out_unlock; | |
3493 | } | |
3494 | ||
a8027073 | 3495 | trace_sched_pi_setprio(p, prio); |
d5f9f942 | 3496 | oldprio = p->prio; |
83ab0aa0 | 3497 | prev_class = p->sched_class; |
da0c1e65 | 3498 | queued = task_on_rq_queued(p); |
051a1d1a | 3499 | running = task_current(rq, p); |
da0c1e65 | 3500 | if (queued) |
1de64443 | 3501 | dequeue_task(rq, p, DEQUEUE_SAVE); |
0e1f3483 | 3502 | if (running) |
f3cd1c4e | 3503 | put_prev_task(rq, p); |
dd41f596 | 3504 | |
2d3d891d DF |
3505 | /* |
3506 | * Boosting condition are: | |
3507 | * 1. -rt task is running and holds mutex A | |
3508 | * --> -dl task blocks on mutex A | |
3509 | * | |
3510 | * 2. -dl task is running and holds mutex A | |
3511 | * --> -dl task blocks on mutex A and could preempt the | |
3512 | * running task | |
3513 | */ | |
3514 | if (dl_prio(prio)) { | |
466af29b ON |
3515 | struct task_struct *pi_task = rt_mutex_get_top_task(p); |
3516 | if (!dl_prio(p->normal_prio) || | |
3517 | (pi_task && dl_entity_preempt(&pi_task->dl, &p->dl))) { | |
2d3d891d | 3518 | p->dl.dl_boosted = 1; |
1de64443 | 3519 | enqueue_flag |= ENQUEUE_REPLENISH; |
2d3d891d DF |
3520 | } else |
3521 | p->dl.dl_boosted = 0; | |
aab03e05 | 3522 | p->sched_class = &dl_sched_class; |
2d3d891d DF |
3523 | } else if (rt_prio(prio)) { |
3524 | if (dl_prio(oldprio)) | |
3525 | p->dl.dl_boosted = 0; | |
3526 | if (oldprio < prio) | |
1de64443 | 3527 | enqueue_flag |= ENQUEUE_HEAD; |
dd41f596 | 3528 | p->sched_class = &rt_sched_class; |
2d3d891d DF |
3529 | } else { |
3530 | if (dl_prio(oldprio)) | |
3531 | p->dl.dl_boosted = 0; | |
746db944 BS |
3532 | if (rt_prio(oldprio)) |
3533 | p->rt.timeout = 0; | |
dd41f596 | 3534 | p->sched_class = &fair_sched_class; |
2d3d891d | 3535 | } |
dd41f596 | 3536 | |
b29739f9 IM |
3537 | p->prio = prio; |
3538 | ||
0e1f3483 HS |
3539 | if (running) |
3540 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 3541 | if (queued) |
2d3d891d | 3542 | enqueue_task(rq, p, enqueue_flag); |
cb469845 | 3543 | |
da7a735e | 3544 | check_class_changed(rq, p, prev_class, oldprio); |
1c4dd99b | 3545 | out_unlock: |
4c9a4bc8 | 3546 | preempt_disable(); /* avoid rq from going away on us */ |
0122ec5b | 3547 | __task_rq_unlock(rq); |
4c9a4bc8 PZ |
3548 | |
3549 | balance_callback(rq); | |
3550 | preempt_enable(); | |
b29739f9 | 3551 | } |
b29739f9 | 3552 | #endif |
d50dde5a | 3553 | |
36c8b586 | 3554 | void set_user_nice(struct task_struct *p, long nice) |
1da177e4 | 3555 | { |
da0c1e65 | 3556 | int old_prio, delta, queued; |
1da177e4 | 3557 | unsigned long flags; |
70b97a7f | 3558 | struct rq *rq; |
1da177e4 | 3559 | |
75e45d51 | 3560 | if (task_nice(p) == nice || nice < MIN_NICE || nice > MAX_NICE) |
1da177e4 LT |
3561 | return; |
3562 | /* | |
3563 | * We have to be careful, if called from sys_setpriority(), | |
3564 | * the task might be in the middle of scheduling on another CPU. | |
3565 | */ | |
3566 | rq = task_rq_lock(p, &flags); | |
3567 | /* | |
3568 | * The RT priorities are set via sched_setscheduler(), but we still | |
3569 | * allow the 'normal' nice value to be set - but as expected | |
3570 | * it wont have any effect on scheduling until the task is | |
aab03e05 | 3571 | * SCHED_DEADLINE, SCHED_FIFO or SCHED_RR: |
1da177e4 | 3572 | */ |
aab03e05 | 3573 | if (task_has_dl_policy(p) || task_has_rt_policy(p)) { |
1da177e4 LT |
3574 | p->static_prio = NICE_TO_PRIO(nice); |
3575 | goto out_unlock; | |
3576 | } | |
da0c1e65 KT |
3577 | queued = task_on_rq_queued(p); |
3578 | if (queued) | |
1de64443 | 3579 | dequeue_task(rq, p, DEQUEUE_SAVE); |
1da177e4 | 3580 | |
1da177e4 | 3581 | p->static_prio = NICE_TO_PRIO(nice); |
2dd73a4f | 3582 | set_load_weight(p); |
b29739f9 IM |
3583 | old_prio = p->prio; |
3584 | p->prio = effective_prio(p); | |
3585 | delta = p->prio - old_prio; | |
1da177e4 | 3586 | |
da0c1e65 | 3587 | if (queued) { |
1de64443 | 3588 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
1da177e4 | 3589 | /* |
d5f9f942 AM |
3590 | * If the task increased its priority or is running and |
3591 | * lowered its priority, then reschedule its CPU: | |
1da177e4 | 3592 | */ |
d5f9f942 | 3593 | if (delta < 0 || (delta > 0 && task_running(rq, p))) |
8875125e | 3594 | resched_curr(rq); |
1da177e4 LT |
3595 | } |
3596 | out_unlock: | |
0122ec5b | 3597 | task_rq_unlock(rq, p, &flags); |
1da177e4 | 3598 | } |
1da177e4 LT |
3599 | EXPORT_SYMBOL(set_user_nice); |
3600 | ||
e43379f1 MM |
3601 | /* |
3602 | * can_nice - check if a task can reduce its nice value | |
3603 | * @p: task | |
3604 | * @nice: nice value | |
3605 | */ | |
36c8b586 | 3606 | int can_nice(const struct task_struct *p, const int nice) |
e43379f1 | 3607 | { |
024f4747 | 3608 | /* convert nice value [19,-20] to rlimit style value [1,40] */ |
7aa2c016 | 3609 | int nice_rlim = nice_to_rlimit(nice); |
48f24c4d | 3610 | |
78d7d407 | 3611 | return (nice_rlim <= task_rlimit(p, RLIMIT_NICE) || |
e43379f1 MM |
3612 | capable(CAP_SYS_NICE)); |
3613 | } | |
3614 | ||
1da177e4 LT |
3615 | #ifdef __ARCH_WANT_SYS_NICE |
3616 | ||
3617 | /* | |
3618 | * sys_nice - change the priority of the current process. | |
3619 | * @increment: priority increment | |
3620 | * | |
3621 | * sys_setpriority is a more generic, but much slower function that | |
3622 | * does similar things. | |
3623 | */ | |
5add95d4 | 3624 | SYSCALL_DEFINE1(nice, int, increment) |
1da177e4 | 3625 | { |
48f24c4d | 3626 | long nice, retval; |
1da177e4 LT |
3627 | |
3628 | /* | |
3629 | * Setpriority might change our priority at the same moment. | |
3630 | * We don't have to worry. Conceptually one call occurs first | |
3631 | * and we have a single winner. | |
3632 | */ | |
a9467fa3 | 3633 | increment = clamp(increment, -NICE_WIDTH, NICE_WIDTH); |
d0ea0268 | 3634 | nice = task_nice(current) + increment; |
1da177e4 | 3635 | |
a9467fa3 | 3636 | nice = clamp_val(nice, MIN_NICE, MAX_NICE); |
e43379f1 MM |
3637 | if (increment < 0 && !can_nice(current, nice)) |
3638 | return -EPERM; | |
3639 | ||
1da177e4 LT |
3640 | retval = security_task_setnice(current, nice); |
3641 | if (retval) | |
3642 | return retval; | |
3643 | ||
3644 | set_user_nice(current, nice); | |
3645 | return 0; | |
3646 | } | |
3647 | ||
3648 | #endif | |
3649 | ||
3650 | /** | |
3651 | * task_prio - return the priority value of a given task. | |
3652 | * @p: the task in question. | |
3653 | * | |
e69f6186 | 3654 | * Return: The priority value as seen by users in /proc. |
1da177e4 LT |
3655 | * RT tasks are offset by -200. Normal tasks are centered |
3656 | * around 0, value goes from -16 to +15. | |
3657 | */ | |
36c8b586 | 3658 | int task_prio(const struct task_struct *p) |
1da177e4 LT |
3659 | { |
3660 | return p->prio - MAX_RT_PRIO; | |
3661 | } | |
3662 | ||
1da177e4 LT |
3663 | /** |
3664 | * idle_cpu - is a given cpu idle currently? | |
3665 | * @cpu: the processor in question. | |
e69f6186 YB |
3666 | * |
3667 | * Return: 1 if the CPU is currently idle. 0 otherwise. | |
1da177e4 LT |
3668 | */ |
3669 | int idle_cpu(int cpu) | |
3670 | { | |
908a3283 TG |
3671 | struct rq *rq = cpu_rq(cpu); |
3672 | ||
3673 | if (rq->curr != rq->idle) | |
3674 | return 0; | |
3675 | ||
3676 | if (rq->nr_running) | |
3677 | return 0; | |
3678 | ||
3679 | #ifdef CONFIG_SMP | |
3680 | if (!llist_empty(&rq->wake_list)) | |
3681 | return 0; | |
3682 | #endif | |
3683 | ||
3684 | return 1; | |
1da177e4 LT |
3685 | } |
3686 | ||
1da177e4 LT |
3687 | /** |
3688 | * idle_task - return the idle task for a given cpu. | |
3689 | * @cpu: the processor in question. | |
e69f6186 YB |
3690 | * |
3691 | * Return: The idle task for the cpu @cpu. | |
1da177e4 | 3692 | */ |
36c8b586 | 3693 | struct task_struct *idle_task(int cpu) |
1da177e4 LT |
3694 | { |
3695 | return cpu_rq(cpu)->idle; | |
3696 | } | |
3697 | ||
3698 | /** | |
3699 | * find_process_by_pid - find a process with a matching PID value. | |
3700 | * @pid: the pid in question. | |
e69f6186 YB |
3701 | * |
3702 | * The task of @pid, if found. %NULL otherwise. | |
1da177e4 | 3703 | */ |
a9957449 | 3704 | static struct task_struct *find_process_by_pid(pid_t pid) |
1da177e4 | 3705 | { |
228ebcbe | 3706 | return pid ? find_task_by_vpid(pid) : current; |
1da177e4 LT |
3707 | } |
3708 | ||
aab03e05 DF |
3709 | /* |
3710 | * This function initializes the sched_dl_entity of a newly becoming | |
3711 | * SCHED_DEADLINE task. | |
3712 | * | |
3713 | * Only the static values are considered here, the actual runtime and the | |
3714 | * absolute deadline will be properly calculated when the task is enqueued | |
3715 | * for the first time with its new policy. | |
3716 | */ | |
3717 | static void | |
3718 | __setparam_dl(struct task_struct *p, const struct sched_attr *attr) | |
3719 | { | |
3720 | struct sched_dl_entity *dl_se = &p->dl; | |
3721 | ||
aab03e05 DF |
3722 | dl_se->dl_runtime = attr->sched_runtime; |
3723 | dl_se->dl_deadline = attr->sched_deadline; | |
755378a4 | 3724 | dl_se->dl_period = attr->sched_period ?: dl_se->dl_deadline; |
aab03e05 | 3725 | dl_se->flags = attr->sched_flags; |
332ac17e | 3726 | dl_se->dl_bw = to_ratio(dl_se->dl_period, dl_se->dl_runtime); |
40767b0d PZ |
3727 | |
3728 | /* | |
3729 | * Changing the parameters of a task is 'tricky' and we're not doing | |
3730 | * the correct thing -- also see task_dead_dl() and switched_from_dl(). | |
3731 | * | |
3732 | * What we SHOULD do is delay the bandwidth release until the 0-lag | |
3733 | * point. This would include retaining the task_struct until that time | |
3734 | * and change dl_overflow() to not immediately decrement the current | |
3735 | * amount. | |
3736 | * | |
3737 | * Instead we retain the current runtime/deadline and let the new | |
3738 | * parameters take effect after the current reservation period lapses. | |
3739 | * This is safe (albeit pessimistic) because the 0-lag point is always | |
3740 | * before the current scheduling deadline. | |
3741 | * | |
3742 | * We can still have temporary overloads because we do not delay the | |
3743 | * change in bandwidth until that time; so admission control is | |
3744 | * not on the safe side. It does however guarantee tasks will never | |
3745 | * consume more than promised. | |
3746 | */ | |
aab03e05 DF |
3747 | } |
3748 | ||
c13db6b1 SR |
3749 | /* |
3750 | * sched_setparam() passes in -1 for its policy, to let the functions | |
3751 | * it calls know not to change it. | |
3752 | */ | |
3753 | #define SETPARAM_POLICY -1 | |
3754 | ||
c365c292 TG |
3755 | static void __setscheduler_params(struct task_struct *p, |
3756 | const struct sched_attr *attr) | |
1da177e4 | 3757 | { |
d50dde5a DF |
3758 | int policy = attr->sched_policy; |
3759 | ||
c13db6b1 | 3760 | if (policy == SETPARAM_POLICY) |
39fd8fd2 PZ |
3761 | policy = p->policy; |
3762 | ||
1da177e4 | 3763 | p->policy = policy; |
d50dde5a | 3764 | |
aab03e05 DF |
3765 | if (dl_policy(policy)) |
3766 | __setparam_dl(p, attr); | |
39fd8fd2 | 3767 | else if (fair_policy(policy)) |
d50dde5a DF |
3768 | p->static_prio = NICE_TO_PRIO(attr->sched_nice); |
3769 | ||
39fd8fd2 PZ |
3770 | /* |
3771 | * __sched_setscheduler() ensures attr->sched_priority == 0 when | |
3772 | * !rt_policy. Always setting this ensures that things like | |
3773 | * getparam()/getattr() don't report silly values for !rt tasks. | |
3774 | */ | |
3775 | p->rt_priority = attr->sched_priority; | |
383afd09 | 3776 | p->normal_prio = normal_prio(p); |
c365c292 TG |
3777 | set_load_weight(p); |
3778 | } | |
39fd8fd2 | 3779 | |
c365c292 TG |
3780 | /* Actually do priority change: must hold pi & rq lock. */ |
3781 | static void __setscheduler(struct rq *rq, struct task_struct *p, | |
0782e63b | 3782 | const struct sched_attr *attr, bool keep_boost) |
c365c292 TG |
3783 | { |
3784 | __setscheduler_params(p, attr); | |
d50dde5a | 3785 | |
383afd09 | 3786 | /* |
0782e63b TG |
3787 | * Keep a potential priority boosting if called from |
3788 | * sched_setscheduler(). | |
383afd09 | 3789 | */ |
0782e63b TG |
3790 | if (keep_boost) |
3791 | p->prio = rt_mutex_get_effective_prio(p, normal_prio(p)); | |
3792 | else | |
3793 | p->prio = normal_prio(p); | |
383afd09 | 3794 | |
aab03e05 DF |
3795 | if (dl_prio(p->prio)) |
3796 | p->sched_class = &dl_sched_class; | |
3797 | else if (rt_prio(p->prio)) | |
ffd44db5 PZ |
3798 | p->sched_class = &rt_sched_class; |
3799 | else | |
3800 | p->sched_class = &fair_sched_class; | |
1da177e4 | 3801 | } |
aab03e05 DF |
3802 | |
3803 | static void | |
3804 | __getparam_dl(struct task_struct *p, struct sched_attr *attr) | |
3805 | { | |
3806 | struct sched_dl_entity *dl_se = &p->dl; | |
3807 | ||
3808 | attr->sched_priority = p->rt_priority; | |
3809 | attr->sched_runtime = dl_se->dl_runtime; | |
3810 | attr->sched_deadline = dl_se->dl_deadline; | |
755378a4 | 3811 | attr->sched_period = dl_se->dl_period; |
aab03e05 DF |
3812 | attr->sched_flags = dl_se->flags; |
3813 | } | |
3814 | ||
3815 | /* | |
3816 | * This function validates the new parameters of a -deadline task. | |
3817 | * We ask for the deadline not being zero, and greater or equal | |
755378a4 | 3818 | * than the runtime, as well as the period of being zero or |
332ac17e | 3819 | * greater than deadline. Furthermore, we have to be sure that |
b0827819 JL |
3820 | * user parameters are above the internal resolution of 1us (we |
3821 | * check sched_runtime only since it is always the smaller one) and | |
3822 | * below 2^63 ns (we have to check both sched_deadline and | |
3823 | * sched_period, as the latter can be zero). | |
aab03e05 DF |
3824 | */ |
3825 | static bool | |
3826 | __checkparam_dl(const struct sched_attr *attr) | |
3827 | { | |
b0827819 JL |
3828 | /* deadline != 0 */ |
3829 | if (attr->sched_deadline == 0) | |
3830 | return false; | |
3831 | ||
3832 | /* | |
3833 | * Since we truncate DL_SCALE bits, make sure we're at least | |
3834 | * that big. | |
3835 | */ | |
3836 | if (attr->sched_runtime < (1ULL << DL_SCALE)) | |
3837 | return false; | |
3838 | ||
3839 | /* | |
3840 | * Since we use the MSB for wrap-around and sign issues, make | |
3841 | * sure it's not set (mind that period can be equal to zero). | |
3842 | */ | |
3843 | if (attr->sched_deadline & (1ULL << 63) || | |
3844 | attr->sched_period & (1ULL << 63)) | |
3845 | return false; | |
3846 | ||
3847 | /* runtime <= deadline <= period (if period != 0) */ | |
3848 | if ((attr->sched_period != 0 && | |
3849 | attr->sched_period < attr->sched_deadline) || | |
3850 | attr->sched_deadline < attr->sched_runtime) | |
3851 | return false; | |
3852 | ||
3853 | return true; | |
aab03e05 DF |
3854 | } |
3855 | ||
c69e8d9c DH |
3856 | /* |
3857 | * check the target process has a UID that matches the current process's | |
3858 | */ | |
3859 | static bool check_same_owner(struct task_struct *p) | |
3860 | { | |
3861 | const struct cred *cred = current_cred(), *pcred; | |
3862 | bool match; | |
3863 | ||
3864 | rcu_read_lock(); | |
3865 | pcred = __task_cred(p); | |
9c806aa0 EB |
3866 | match = (uid_eq(cred->euid, pcred->euid) || |
3867 | uid_eq(cred->euid, pcred->uid)); | |
c69e8d9c DH |
3868 | rcu_read_unlock(); |
3869 | return match; | |
3870 | } | |
3871 | ||
75381608 WL |
3872 | static bool dl_param_changed(struct task_struct *p, |
3873 | const struct sched_attr *attr) | |
3874 | { | |
3875 | struct sched_dl_entity *dl_se = &p->dl; | |
3876 | ||
3877 | if (dl_se->dl_runtime != attr->sched_runtime || | |
3878 | dl_se->dl_deadline != attr->sched_deadline || | |
3879 | dl_se->dl_period != attr->sched_period || | |
3880 | dl_se->flags != attr->sched_flags) | |
3881 | return true; | |
3882 | ||
3883 | return false; | |
3884 | } | |
3885 | ||
d50dde5a DF |
3886 | static int __sched_setscheduler(struct task_struct *p, |
3887 | const struct sched_attr *attr, | |
dbc7f069 | 3888 | bool user, bool pi) |
1da177e4 | 3889 | { |
383afd09 SR |
3890 | int newprio = dl_policy(attr->sched_policy) ? MAX_DL_PRIO - 1 : |
3891 | MAX_RT_PRIO - 1 - attr->sched_priority; | |
da0c1e65 | 3892 | int retval, oldprio, oldpolicy = -1, queued, running; |
0782e63b | 3893 | int new_effective_prio, policy = attr->sched_policy; |
1da177e4 | 3894 | unsigned long flags; |
83ab0aa0 | 3895 | const struct sched_class *prev_class; |
70b97a7f | 3896 | struct rq *rq; |
ca94c442 | 3897 | int reset_on_fork; |
1da177e4 | 3898 | |
66e5393a SR |
3899 | /* may grab non-irq protected spin_locks */ |
3900 | BUG_ON(in_interrupt()); | |
1da177e4 LT |
3901 | recheck: |
3902 | /* double check policy once rq lock held */ | |
ca94c442 LP |
3903 | if (policy < 0) { |
3904 | reset_on_fork = p->sched_reset_on_fork; | |
1da177e4 | 3905 | policy = oldpolicy = p->policy; |
ca94c442 | 3906 | } else { |
7479f3c9 | 3907 | reset_on_fork = !!(attr->sched_flags & SCHED_FLAG_RESET_ON_FORK); |
ca94c442 | 3908 | |
20f9cd2a | 3909 | if (!valid_policy(policy)) |
ca94c442 LP |
3910 | return -EINVAL; |
3911 | } | |
3912 | ||
7479f3c9 PZ |
3913 | if (attr->sched_flags & ~(SCHED_FLAG_RESET_ON_FORK)) |
3914 | return -EINVAL; | |
3915 | ||
1da177e4 LT |
3916 | /* |
3917 | * Valid priorities for SCHED_FIFO and SCHED_RR are | |
dd41f596 IM |
3918 | * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
3919 | * SCHED_BATCH and SCHED_IDLE is 0. | |
1da177e4 | 3920 | */ |
0bb040a4 | 3921 | if ((p->mm && attr->sched_priority > MAX_USER_RT_PRIO-1) || |
d50dde5a | 3922 | (!p->mm && attr->sched_priority > MAX_RT_PRIO-1)) |
1da177e4 | 3923 | return -EINVAL; |
aab03e05 DF |
3924 | if ((dl_policy(policy) && !__checkparam_dl(attr)) || |
3925 | (rt_policy(policy) != (attr->sched_priority != 0))) | |
1da177e4 LT |
3926 | return -EINVAL; |
3927 | ||
37e4ab3f OC |
3928 | /* |
3929 | * Allow unprivileged RT tasks to decrease priority: | |
3930 | */ | |
961ccddd | 3931 | if (user && !capable(CAP_SYS_NICE)) { |
d50dde5a | 3932 | if (fair_policy(policy)) { |
d0ea0268 | 3933 | if (attr->sched_nice < task_nice(p) && |
eaad4513 | 3934 | !can_nice(p, attr->sched_nice)) |
d50dde5a DF |
3935 | return -EPERM; |
3936 | } | |
3937 | ||
e05606d3 | 3938 | if (rt_policy(policy)) { |
a44702e8 ON |
3939 | unsigned long rlim_rtprio = |
3940 | task_rlimit(p, RLIMIT_RTPRIO); | |
8dc3e909 ON |
3941 | |
3942 | /* can't set/change the rt policy */ | |
3943 | if (policy != p->policy && !rlim_rtprio) | |
3944 | return -EPERM; | |
3945 | ||
3946 | /* can't increase priority */ | |
d50dde5a DF |
3947 | if (attr->sched_priority > p->rt_priority && |
3948 | attr->sched_priority > rlim_rtprio) | |
8dc3e909 ON |
3949 | return -EPERM; |
3950 | } | |
c02aa73b | 3951 | |
d44753b8 JL |
3952 | /* |
3953 | * Can't set/change SCHED_DEADLINE policy at all for now | |
3954 | * (safest behavior); in the future we would like to allow | |
3955 | * unprivileged DL tasks to increase their relative deadline | |
3956 | * or reduce their runtime (both ways reducing utilization) | |
3957 | */ | |
3958 | if (dl_policy(policy)) | |
3959 | return -EPERM; | |
3960 | ||
dd41f596 | 3961 | /* |
c02aa73b DH |
3962 | * Treat SCHED_IDLE as nice 20. Only allow a switch to |
3963 | * SCHED_NORMAL if the RLIMIT_NICE would normally permit it. | |
dd41f596 | 3964 | */ |
20f9cd2a | 3965 | if (idle_policy(p->policy) && !idle_policy(policy)) { |
d0ea0268 | 3966 | if (!can_nice(p, task_nice(p))) |
c02aa73b DH |
3967 | return -EPERM; |
3968 | } | |
5fe1d75f | 3969 | |
37e4ab3f | 3970 | /* can't change other user's priorities */ |
c69e8d9c | 3971 | if (!check_same_owner(p)) |
37e4ab3f | 3972 | return -EPERM; |
ca94c442 LP |
3973 | |
3974 | /* Normal users shall not reset the sched_reset_on_fork flag */ | |
3975 | if (p->sched_reset_on_fork && !reset_on_fork) | |
3976 | return -EPERM; | |
37e4ab3f | 3977 | } |
1da177e4 | 3978 | |
725aad24 | 3979 | if (user) { |
b0ae1981 | 3980 | retval = security_task_setscheduler(p); |
725aad24 JF |
3981 | if (retval) |
3982 | return retval; | |
3983 | } | |
3984 | ||
b29739f9 IM |
3985 | /* |
3986 | * make sure no PI-waiters arrive (or leave) while we are | |
3987 | * changing the priority of the task: | |
0122ec5b | 3988 | * |
25985edc | 3989 | * To be able to change p->policy safely, the appropriate |
1da177e4 LT |
3990 | * runqueue lock must be held. |
3991 | */ | |
0122ec5b | 3992 | rq = task_rq_lock(p, &flags); |
dc61b1d6 | 3993 | |
34f971f6 PZ |
3994 | /* |
3995 | * Changing the policy of the stop threads its a very bad idea | |
3996 | */ | |
3997 | if (p == rq->stop) { | |
0122ec5b | 3998 | task_rq_unlock(rq, p, &flags); |
34f971f6 PZ |
3999 | return -EINVAL; |
4000 | } | |
4001 | ||
a51e9198 | 4002 | /* |
d6b1e911 TG |
4003 | * If not changing anything there's no need to proceed further, |
4004 | * but store a possible modification of reset_on_fork. | |
a51e9198 | 4005 | */ |
d50dde5a | 4006 | if (unlikely(policy == p->policy)) { |
d0ea0268 | 4007 | if (fair_policy(policy) && attr->sched_nice != task_nice(p)) |
d50dde5a DF |
4008 | goto change; |
4009 | if (rt_policy(policy) && attr->sched_priority != p->rt_priority) | |
4010 | goto change; | |
75381608 | 4011 | if (dl_policy(policy) && dl_param_changed(p, attr)) |
aab03e05 | 4012 | goto change; |
d50dde5a | 4013 | |
d6b1e911 | 4014 | p->sched_reset_on_fork = reset_on_fork; |
45afb173 | 4015 | task_rq_unlock(rq, p, &flags); |
a51e9198 DF |
4016 | return 0; |
4017 | } | |
d50dde5a | 4018 | change: |
a51e9198 | 4019 | |
dc61b1d6 | 4020 | if (user) { |
332ac17e | 4021 | #ifdef CONFIG_RT_GROUP_SCHED |
dc61b1d6 PZ |
4022 | /* |
4023 | * Do not allow realtime tasks into groups that have no runtime | |
4024 | * assigned. | |
4025 | */ | |
4026 | if (rt_bandwidth_enabled() && rt_policy(policy) && | |
f4493771 MG |
4027 | task_group(p)->rt_bandwidth.rt_runtime == 0 && |
4028 | !task_group_is_autogroup(task_group(p))) { | |
0122ec5b | 4029 | task_rq_unlock(rq, p, &flags); |
dc61b1d6 PZ |
4030 | return -EPERM; |
4031 | } | |
dc61b1d6 | 4032 | #endif |
332ac17e DF |
4033 | #ifdef CONFIG_SMP |
4034 | if (dl_bandwidth_enabled() && dl_policy(policy)) { | |
4035 | cpumask_t *span = rq->rd->span; | |
332ac17e DF |
4036 | |
4037 | /* | |
4038 | * Don't allow tasks with an affinity mask smaller than | |
4039 | * the entire root_domain to become SCHED_DEADLINE. We | |
4040 | * will also fail if there's no bandwidth available. | |
4041 | */ | |
e4099a5e PZ |
4042 | if (!cpumask_subset(span, &p->cpus_allowed) || |
4043 | rq->rd->dl_bw.bw == 0) { | |
332ac17e DF |
4044 | task_rq_unlock(rq, p, &flags); |
4045 | return -EPERM; | |
4046 | } | |
4047 | } | |
4048 | #endif | |
4049 | } | |
dc61b1d6 | 4050 | |
1da177e4 LT |
4051 | /* recheck policy now with rq lock held */ |
4052 | if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { | |
4053 | policy = oldpolicy = -1; | |
0122ec5b | 4054 | task_rq_unlock(rq, p, &flags); |
1da177e4 LT |
4055 | goto recheck; |
4056 | } | |
332ac17e DF |
4057 | |
4058 | /* | |
4059 | * If setscheduling to SCHED_DEADLINE (or changing the parameters | |
4060 | * of a SCHED_DEADLINE task) we need to check if enough bandwidth | |
4061 | * is available. | |
4062 | */ | |
e4099a5e | 4063 | if ((dl_policy(policy) || dl_task(p)) && dl_overflow(p, policy, attr)) { |
332ac17e DF |
4064 | task_rq_unlock(rq, p, &flags); |
4065 | return -EBUSY; | |
4066 | } | |
4067 | ||
c365c292 TG |
4068 | p->sched_reset_on_fork = reset_on_fork; |
4069 | oldprio = p->prio; | |
4070 | ||
dbc7f069 PZ |
4071 | if (pi) { |
4072 | /* | |
4073 | * Take priority boosted tasks into account. If the new | |
4074 | * effective priority is unchanged, we just store the new | |
4075 | * normal parameters and do not touch the scheduler class and | |
4076 | * the runqueue. This will be done when the task deboost | |
4077 | * itself. | |
4078 | */ | |
4079 | new_effective_prio = rt_mutex_get_effective_prio(p, newprio); | |
4080 | if (new_effective_prio == oldprio) { | |
4081 | __setscheduler_params(p, attr); | |
4082 | task_rq_unlock(rq, p, &flags); | |
4083 | return 0; | |
4084 | } | |
c365c292 TG |
4085 | } |
4086 | ||
da0c1e65 | 4087 | queued = task_on_rq_queued(p); |
051a1d1a | 4088 | running = task_current(rq, p); |
da0c1e65 | 4089 | if (queued) |
1de64443 | 4090 | dequeue_task(rq, p, DEQUEUE_SAVE); |
0e1f3483 | 4091 | if (running) |
f3cd1c4e | 4092 | put_prev_task(rq, p); |
f6b53205 | 4093 | |
83ab0aa0 | 4094 | prev_class = p->sched_class; |
dbc7f069 | 4095 | __setscheduler(rq, p, attr, pi); |
f6b53205 | 4096 | |
0e1f3483 HS |
4097 | if (running) |
4098 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 4099 | if (queued) { |
1de64443 | 4100 | int enqueue_flags = ENQUEUE_RESTORE; |
81a44c54 TG |
4101 | /* |
4102 | * We enqueue to tail when the priority of a task is | |
4103 | * increased (user space view). | |
4104 | */ | |
1de64443 PZ |
4105 | if (oldprio <= p->prio) |
4106 | enqueue_flags |= ENQUEUE_HEAD; | |
4107 | ||
4108 | enqueue_task(rq, p, enqueue_flags); | |
81a44c54 | 4109 | } |
cb469845 | 4110 | |
da7a735e | 4111 | check_class_changed(rq, p, prev_class, oldprio); |
4c9a4bc8 | 4112 | preempt_disable(); /* avoid rq from going away on us */ |
0122ec5b | 4113 | task_rq_unlock(rq, p, &flags); |
b29739f9 | 4114 | |
dbc7f069 PZ |
4115 | if (pi) |
4116 | rt_mutex_adjust_pi(p); | |
95e02ca9 | 4117 | |
4c9a4bc8 PZ |
4118 | /* |
4119 | * Run balance callbacks after we've adjusted the PI chain. | |
4120 | */ | |
4121 | balance_callback(rq); | |
4122 | preempt_enable(); | |
95e02ca9 | 4123 | |
1da177e4 LT |
4124 | return 0; |
4125 | } | |
961ccddd | 4126 | |
7479f3c9 PZ |
4127 | static int _sched_setscheduler(struct task_struct *p, int policy, |
4128 | const struct sched_param *param, bool check) | |
4129 | { | |
4130 | struct sched_attr attr = { | |
4131 | .sched_policy = policy, | |
4132 | .sched_priority = param->sched_priority, | |
4133 | .sched_nice = PRIO_TO_NICE(p->static_prio), | |
4134 | }; | |
4135 | ||
c13db6b1 SR |
4136 | /* Fixup the legacy SCHED_RESET_ON_FORK hack. */ |
4137 | if ((policy != SETPARAM_POLICY) && (policy & SCHED_RESET_ON_FORK)) { | |
7479f3c9 PZ |
4138 | attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; |
4139 | policy &= ~SCHED_RESET_ON_FORK; | |
4140 | attr.sched_policy = policy; | |
4141 | } | |
4142 | ||
dbc7f069 | 4143 | return __sched_setscheduler(p, &attr, check, true); |
7479f3c9 | 4144 | } |
961ccddd RR |
4145 | /** |
4146 | * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. | |
4147 | * @p: the task in question. | |
4148 | * @policy: new policy. | |
4149 | * @param: structure containing the new RT priority. | |
4150 | * | |
e69f6186 YB |
4151 | * Return: 0 on success. An error code otherwise. |
4152 | * | |
961ccddd RR |
4153 | * NOTE that the task may be already dead. |
4154 | */ | |
4155 | int sched_setscheduler(struct task_struct *p, int policy, | |
fe7de49f | 4156 | const struct sched_param *param) |
961ccddd | 4157 | { |
7479f3c9 | 4158 | return _sched_setscheduler(p, policy, param, true); |
961ccddd | 4159 | } |
1da177e4 LT |
4160 | EXPORT_SYMBOL_GPL(sched_setscheduler); |
4161 | ||
d50dde5a DF |
4162 | int sched_setattr(struct task_struct *p, const struct sched_attr *attr) |
4163 | { | |
dbc7f069 | 4164 | return __sched_setscheduler(p, attr, true, true); |
d50dde5a DF |
4165 | } |
4166 | EXPORT_SYMBOL_GPL(sched_setattr); | |
4167 | ||
961ccddd RR |
4168 | /** |
4169 | * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. | |
4170 | * @p: the task in question. | |
4171 | * @policy: new policy. | |
4172 | * @param: structure containing the new RT priority. | |
4173 | * | |
4174 | * Just like sched_setscheduler, only don't bother checking if the | |
4175 | * current context has permission. For example, this is needed in | |
4176 | * stop_machine(): we create temporary high priority worker threads, | |
4177 | * but our caller might not have that capability. | |
e69f6186 YB |
4178 | * |
4179 | * Return: 0 on success. An error code otherwise. | |
961ccddd RR |
4180 | */ |
4181 | int sched_setscheduler_nocheck(struct task_struct *p, int policy, | |
fe7de49f | 4182 | const struct sched_param *param) |
961ccddd | 4183 | { |
7479f3c9 | 4184 | return _sched_setscheduler(p, policy, param, false); |
961ccddd | 4185 | } |
84778472 | 4186 | EXPORT_SYMBOL_GPL(sched_setscheduler_nocheck); |
961ccddd | 4187 | |
95cdf3b7 IM |
4188 | static int |
4189 | do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) | |
1da177e4 | 4190 | { |
1da177e4 LT |
4191 | struct sched_param lparam; |
4192 | struct task_struct *p; | |
36c8b586 | 4193 | int retval; |
1da177e4 LT |
4194 | |
4195 | if (!param || pid < 0) | |
4196 | return -EINVAL; | |
4197 | if (copy_from_user(&lparam, param, sizeof(struct sched_param))) | |
4198 | return -EFAULT; | |
5fe1d75f ON |
4199 | |
4200 | rcu_read_lock(); | |
4201 | retval = -ESRCH; | |
1da177e4 | 4202 | p = find_process_by_pid(pid); |
5fe1d75f ON |
4203 | if (p != NULL) |
4204 | retval = sched_setscheduler(p, policy, &lparam); | |
4205 | rcu_read_unlock(); | |
36c8b586 | 4206 | |
1da177e4 LT |
4207 | return retval; |
4208 | } | |
4209 | ||
d50dde5a DF |
4210 | /* |
4211 | * Mimics kernel/events/core.c perf_copy_attr(). | |
4212 | */ | |
4213 | static int sched_copy_attr(struct sched_attr __user *uattr, | |
4214 | struct sched_attr *attr) | |
4215 | { | |
4216 | u32 size; | |
4217 | int ret; | |
4218 | ||
4219 | if (!access_ok(VERIFY_WRITE, uattr, SCHED_ATTR_SIZE_VER0)) | |
4220 | return -EFAULT; | |
4221 | ||
4222 | /* | |
4223 | * zero the full structure, so that a short copy will be nice. | |
4224 | */ | |
4225 | memset(attr, 0, sizeof(*attr)); | |
4226 | ||
4227 | ret = get_user(size, &uattr->size); | |
4228 | if (ret) | |
4229 | return ret; | |
4230 | ||
4231 | if (size > PAGE_SIZE) /* silly large */ | |
4232 | goto err_size; | |
4233 | ||
4234 | if (!size) /* abi compat */ | |
4235 | size = SCHED_ATTR_SIZE_VER0; | |
4236 | ||
4237 | if (size < SCHED_ATTR_SIZE_VER0) | |
4238 | goto err_size; | |
4239 | ||
4240 | /* | |
4241 | * If we're handed a bigger struct than we know of, | |
4242 | * ensure all the unknown bits are 0 - i.e. new | |
4243 | * user-space does not rely on any kernel feature | |
4244 | * extensions we dont know about yet. | |
4245 | */ | |
4246 | if (size > sizeof(*attr)) { | |
4247 | unsigned char __user *addr; | |
4248 | unsigned char __user *end; | |
4249 | unsigned char val; | |
4250 | ||
4251 | addr = (void __user *)uattr + sizeof(*attr); | |
4252 | end = (void __user *)uattr + size; | |
4253 | ||
4254 | for (; addr < end; addr++) { | |
4255 | ret = get_user(val, addr); | |
4256 | if (ret) | |
4257 | return ret; | |
4258 | if (val) | |
4259 | goto err_size; | |
4260 | } | |
4261 | size = sizeof(*attr); | |
4262 | } | |
4263 | ||
4264 | ret = copy_from_user(attr, uattr, size); | |
4265 | if (ret) | |
4266 | return -EFAULT; | |
4267 | ||
4268 | /* | |
4269 | * XXX: do we want to be lenient like existing syscalls; or do we want | |
4270 | * to be strict and return an error on out-of-bounds values? | |
4271 | */ | |
75e45d51 | 4272 | attr->sched_nice = clamp(attr->sched_nice, MIN_NICE, MAX_NICE); |
d50dde5a | 4273 | |
e78c7bca | 4274 | return 0; |
d50dde5a DF |
4275 | |
4276 | err_size: | |
4277 | put_user(sizeof(*attr), &uattr->size); | |
e78c7bca | 4278 | return -E2BIG; |
d50dde5a DF |
4279 | } |
4280 | ||
1da177e4 LT |
4281 | /** |
4282 | * sys_sched_setscheduler - set/change the scheduler policy and RT priority | |
4283 | * @pid: the pid in question. | |
4284 | * @policy: new policy. | |
4285 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
4286 | * |
4287 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4288 | */ |
5add95d4 HC |
4289 | SYSCALL_DEFINE3(sched_setscheduler, pid_t, pid, int, policy, |
4290 | struct sched_param __user *, param) | |
1da177e4 | 4291 | { |
c21761f1 JB |
4292 | /* negative values for policy are not valid */ |
4293 | if (policy < 0) | |
4294 | return -EINVAL; | |
4295 | ||
1da177e4 LT |
4296 | return do_sched_setscheduler(pid, policy, param); |
4297 | } | |
4298 | ||
4299 | /** | |
4300 | * sys_sched_setparam - set/change the RT priority of a thread | |
4301 | * @pid: the pid in question. | |
4302 | * @param: structure containing the new RT priority. | |
e69f6186 YB |
4303 | * |
4304 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4305 | */ |
5add95d4 | 4306 | SYSCALL_DEFINE2(sched_setparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 | 4307 | { |
c13db6b1 | 4308 | return do_sched_setscheduler(pid, SETPARAM_POLICY, param); |
1da177e4 LT |
4309 | } |
4310 | ||
d50dde5a DF |
4311 | /** |
4312 | * sys_sched_setattr - same as above, but with extended sched_attr | |
4313 | * @pid: the pid in question. | |
5778fccf | 4314 | * @uattr: structure containing the extended parameters. |
db66d756 | 4315 | * @flags: for future extension. |
d50dde5a | 4316 | */ |
6d35ab48 PZ |
4317 | SYSCALL_DEFINE3(sched_setattr, pid_t, pid, struct sched_attr __user *, uattr, |
4318 | unsigned int, flags) | |
d50dde5a DF |
4319 | { |
4320 | struct sched_attr attr; | |
4321 | struct task_struct *p; | |
4322 | int retval; | |
4323 | ||
6d35ab48 | 4324 | if (!uattr || pid < 0 || flags) |
d50dde5a DF |
4325 | return -EINVAL; |
4326 | ||
143cf23d MK |
4327 | retval = sched_copy_attr(uattr, &attr); |
4328 | if (retval) | |
4329 | return retval; | |
d50dde5a | 4330 | |
b14ed2c2 | 4331 | if ((int)attr.sched_policy < 0) |
dbdb2275 | 4332 | return -EINVAL; |
d50dde5a DF |
4333 | |
4334 | rcu_read_lock(); | |
4335 | retval = -ESRCH; | |
4336 | p = find_process_by_pid(pid); | |
4337 | if (p != NULL) | |
4338 | retval = sched_setattr(p, &attr); | |
4339 | rcu_read_unlock(); | |
4340 | ||
4341 | return retval; | |
4342 | } | |
4343 | ||
1da177e4 LT |
4344 | /** |
4345 | * sys_sched_getscheduler - get the policy (scheduling class) of a thread | |
4346 | * @pid: the pid in question. | |
e69f6186 YB |
4347 | * |
4348 | * Return: On success, the policy of the thread. Otherwise, a negative error | |
4349 | * code. | |
1da177e4 | 4350 | */ |
5add95d4 | 4351 | SYSCALL_DEFINE1(sched_getscheduler, pid_t, pid) |
1da177e4 | 4352 | { |
36c8b586 | 4353 | struct task_struct *p; |
3a5c359a | 4354 | int retval; |
1da177e4 LT |
4355 | |
4356 | if (pid < 0) | |
3a5c359a | 4357 | return -EINVAL; |
1da177e4 LT |
4358 | |
4359 | retval = -ESRCH; | |
5fe85be0 | 4360 | rcu_read_lock(); |
1da177e4 LT |
4361 | p = find_process_by_pid(pid); |
4362 | if (p) { | |
4363 | retval = security_task_getscheduler(p); | |
4364 | if (!retval) | |
ca94c442 LP |
4365 | retval = p->policy |
4366 | | (p->sched_reset_on_fork ? SCHED_RESET_ON_FORK : 0); | |
1da177e4 | 4367 | } |
5fe85be0 | 4368 | rcu_read_unlock(); |
1da177e4 LT |
4369 | return retval; |
4370 | } | |
4371 | ||
4372 | /** | |
ca94c442 | 4373 | * sys_sched_getparam - get the RT priority of a thread |
1da177e4 LT |
4374 | * @pid: the pid in question. |
4375 | * @param: structure containing the RT priority. | |
e69f6186 YB |
4376 | * |
4377 | * Return: On success, 0 and the RT priority is in @param. Otherwise, an error | |
4378 | * code. | |
1da177e4 | 4379 | */ |
5add95d4 | 4380 | SYSCALL_DEFINE2(sched_getparam, pid_t, pid, struct sched_param __user *, param) |
1da177e4 | 4381 | { |
ce5f7f82 | 4382 | struct sched_param lp = { .sched_priority = 0 }; |
36c8b586 | 4383 | struct task_struct *p; |
3a5c359a | 4384 | int retval; |
1da177e4 LT |
4385 | |
4386 | if (!param || pid < 0) | |
3a5c359a | 4387 | return -EINVAL; |
1da177e4 | 4388 | |
5fe85be0 | 4389 | rcu_read_lock(); |
1da177e4 LT |
4390 | p = find_process_by_pid(pid); |
4391 | retval = -ESRCH; | |
4392 | if (!p) | |
4393 | goto out_unlock; | |
4394 | ||
4395 | retval = security_task_getscheduler(p); | |
4396 | if (retval) | |
4397 | goto out_unlock; | |
4398 | ||
ce5f7f82 PZ |
4399 | if (task_has_rt_policy(p)) |
4400 | lp.sched_priority = p->rt_priority; | |
5fe85be0 | 4401 | rcu_read_unlock(); |
1da177e4 LT |
4402 | |
4403 | /* | |
4404 | * This one might sleep, we cannot do it with a spinlock held ... | |
4405 | */ | |
4406 | retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; | |
4407 | ||
1da177e4 LT |
4408 | return retval; |
4409 | ||
4410 | out_unlock: | |
5fe85be0 | 4411 | rcu_read_unlock(); |
1da177e4 LT |
4412 | return retval; |
4413 | } | |
4414 | ||
d50dde5a DF |
4415 | static int sched_read_attr(struct sched_attr __user *uattr, |
4416 | struct sched_attr *attr, | |
4417 | unsigned int usize) | |
4418 | { | |
4419 | int ret; | |
4420 | ||
4421 | if (!access_ok(VERIFY_WRITE, uattr, usize)) | |
4422 | return -EFAULT; | |
4423 | ||
4424 | /* | |
4425 | * If we're handed a smaller struct than we know of, | |
4426 | * ensure all the unknown bits are 0 - i.e. old | |
4427 | * user-space does not get uncomplete information. | |
4428 | */ | |
4429 | if (usize < sizeof(*attr)) { | |
4430 | unsigned char *addr; | |
4431 | unsigned char *end; | |
4432 | ||
4433 | addr = (void *)attr + usize; | |
4434 | end = (void *)attr + sizeof(*attr); | |
4435 | ||
4436 | for (; addr < end; addr++) { | |
4437 | if (*addr) | |
22400674 | 4438 | return -EFBIG; |
d50dde5a DF |
4439 | } |
4440 | ||
4441 | attr->size = usize; | |
4442 | } | |
4443 | ||
4efbc454 | 4444 | ret = copy_to_user(uattr, attr, attr->size); |
d50dde5a DF |
4445 | if (ret) |
4446 | return -EFAULT; | |
4447 | ||
22400674 | 4448 | return 0; |
d50dde5a DF |
4449 | } |
4450 | ||
4451 | /** | |
aab03e05 | 4452 | * sys_sched_getattr - similar to sched_getparam, but with sched_attr |
d50dde5a | 4453 | * @pid: the pid in question. |
5778fccf | 4454 | * @uattr: structure containing the extended parameters. |
d50dde5a | 4455 | * @size: sizeof(attr) for fwd/bwd comp. |
db66d756 | 4456 | * @flags: for future extension. |
d50dde5a | 4457 | */ |
6d35ab48 PZ |
4458 | SYSCALL_DEFINE4(sched_getattr, pid_t, pid, struct sched_attr __user *, uattr, |
4459 | unsigned int, size, unsigned int, flags) | |
d50dde5a DF |
4460 | { |
4461 | struct sched_attr attr = { | |
4462 | .size = sizeof(struct sched_attr), | |
4463 | }; | |
4464 | struct task_struct *p; | |
4465 | int retval; | |
4466 | ||
4467 | if (!uattr || pid < 0 || size > PAGE_SIZE || | |
6d35ab48 | 4468 | size < SCHED_ATTR_SIZE_VER0 || flags) |
d50dde5a DF |
4469 | return -EINVAL; |
4470 | ||
4471 | rcu_read_lock(); | |
4472 | p = find_process_by_pid(pid); | |
4473 | retval = -ESRCH; | |
4474 | if (!p) | |
4475 | goto out_unlock; | |
4476 | ||
4477 | retval = security_task_getscheduler(p); | |
4478 | if (retval) | |
4479 | goto out_unlock; | |
4480 | ||
4481 | attr.sched_policy = p->policy; | |
7479f3c9 PZ |
4482 | if (p->sched_reset_on_fork) |
4483 | attr.sched_flags |= SCHED_FLAG_RESET_ON_FORK; | |
aab03e05 DF |
4484 | if (task_has_dl_policy(p)) |
4485 | __getparam_dl(p, &attr); | |
4486 | else if (task_has_rt_policy(p)) | |
d50dde5a DF |
4487 | attr.sched_priority = p->rt_priority; |
4488 | else | |
d0ea0268 | 4489 | attr.sched_nice = task_nice(p); |
d50dde5a DF |
4490 | |
4491 | rcu_read_unlock(); | |
4492 | ||
4493 | retval = sched_read_attr(uattr, &attr, size); | |
4494 | return retval; | |
4495 | ||
4496 | out_unlock: | |
4497 | rcu_read_unlock(); | |
4498 | return retval; | |
4499 | } | |
4500 | ||
96f874e2 | 4501 | long sched_setaffinity(pid_t pid, const struct cpumask *in_mask) |
1da177e4 | 4502 | { |
5a16f3d3 | 4503 | cpumask_var_t cpus_allowed, new_mask; |
36c8b586 IM |
4504 | struct task_struct *p; |
4505 | int retval; | |
1da177e4 | 4506 | |
23f5d142 | 4507 | rcu_read_lock(); |
1da177e4 LT |
4508 | |
4509 | p = find_process_by_pid(pid); | |
4510 | if (!p) { | |
23f5d142 | 4511 | rcu_read_unlock(); |
1da177e4 LT |
4512 | return -ESRCH; |
4513 | } | |
4514 | ||
23f5d142 | 4515 | /* Prevent p going away */ |
1da177e4 | 4516 | get_task_struct(p); |
23f5d142 | 4517 | rcu_read_unlock(); |
1da177e4 | 4518 | |
14a40ffc TH |
4519 | if (p->flags & PF_NO_SETAFFINITY) { |
4520 | retval = -EINVAL; | |
4521 | goto out_put_task; | |
4522 | } | |
5a16f3d3 RR |
4523 | if (!alloc_cpumask_var(&cpus_allowed, GFP_KERNEL)) { |
4524 | retval = -ENOMEM; | |
4525 | goto out_put_task; | |
4526 | } | |
4527 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) { | |
4528 | retval = -ENOMEM; | |
4529 | goto out_free_cpus_allowed; | |
4530 | } | |
1da177e4 | 4531 | retval = -EPERM; |
4c44aaaf EB |
4532 | if (!check_same_owner(p)) { |
4533 | rcu_read_lock(); | |
4534 | if (!ns_capable(__task_cred(p)->user_ns, CAP_SYS_NICE)) { | |
4535 | rcu_read_unlock(); | |
16303ab2 | 4536 | goto out_free_new_mask; |
4c44aaaf EB |
4537 | } |
4538 | rcu_read_unlock(); | |
4539 | } | |
1da177e4 | 4540 | |
b0ae1981 | 4541 | retval = security_task_setscheduler(p); |
e7834f8f | 4542 | if (retval) |
16303ab2 | 4543 | goto out_free_new_mask; |
e7834f8f | 4544 | |
e4099a5e PZ |
4545 | |
4546 | cpuset_cpus_allowed(p, cpus_allowed); | |
4547 | cpumask_and(new_mask, in_mask, cpus_allowed); | |
4548 | ||
332ac17e DF |
4549 | /* |
4550 | * Since bandwidth control happens on root_domain basis, | |
4551 | * if admission test is enabled, we only admit -deadline | |
4552 | * tasks allowed to run on all the CPUs in the task's | |
4553 | * root_domain. | |
4554 | */ | |
4555 | #ifdef CONFIG_SMP | |
f1e3a093 KT |
4556 | if (task_has_dl_policy(p) && dl_bandwidth_enabled()) { |
4557 | rcu_read_lock(); | |
4558 | if (!cpumask_subset(task_rq(p)->rd->span, new_mask)) { | |
332ac17e | 4559 | retval = -EBUSY; |
f1e3a093 | 4560 | rcu_read_unlock(); |
16303ab2 | 4561 | goto out_free_new_mask; |
332ac17e | 4562 | } |
f1e3a093 | 4563 | rcu_read_unlock(); |
332ac17e DF |
4564 | } |
4565 | #endif | |
49246274 | 4566 | again: |
25834c73 | 4567 | retval = __set_cpus_allowed_ptr(p, new_mask, true); |
1da177e4 | 4568 | |
8707d8b8 | 4569 | if (!retval) { |
5a16f3d3 RR |
4570 | cpuset_cpus_allowed(p, cpus_allowed); |
4571 | if (!cpumask_subset(new_mask, cpus_allowed)) { | |
8707d8b8 PM |
4572 | /* |
4573 | * We must have raced with a concurrent cpuset | |
4574 | * update. Just reset the cpus_allowed to the | |
4575 | * cpuset's cpus_allowed | |
4576 | */ | |
5a16f3d3 | 4577 | cpumask_copy(new_mask, cpus_allowed); |
8707d8b8 PM |
4578 | goto again; |
4579 | } | |
4580 | } | |
16303ab2 | 4581 | out_free_new_mask: |
5a16f3d3 RR |
4582 | free_cpumask_var(new_mask); |
4583 | out_free_cpus_allowed: | |
4584 | free_cpumask_var(cpus_allowed); | |
4585 | out_put_task: | |
1da177e4 | 4586 | put_task_struct(p); |
1da177e4 LT |
4587 | return retval; |
4588 | } | |
4589 | ||
4590 | static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, | |
96f874e2 | 4591 | struct cpumask *new_mask) |
1da177e4 | 4592 | { |
96f874e2 RR |
4593 | if (len < cpumask_size()) |
4594 | cpumask_clear(new_mask); | |
4595 | else if (len > cpumask_size()) | |
4596 | len = cpumask_size(); | |
4597 | ||
1da177e4 LT |
4598 | return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
4599 | } | |
4600 | ||
4601 | /** | |
4602 | * sys_sched_setaffinity - set the cpu affinity of a process | |
4603 | * @pid: pid of the process | |
4604 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4605 | * @user_mask_ptr: user-space pointer to the new cpu mask | |
e69f6186 YB |
4606 | * |
4607 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4608 | */ |
5add95d4 HC |
4609 | SYSCALL_DEFINE3(sched_setaffinity, pid_t, pid, unsigned int, len, |
4610 | unsigned long __user *, user_mask_ptr) | |
1da177e4 | 4611 | { |
5a16f3d3 | 4612 | cpumask_var_t new_mask; |
1da177e4 LT |
4613 | int retval; |
4614 | ||
5a16f3d3 RR |
4615 | if (!alloc_cpumask_var(&new_mask, GFP_KERNEL)) |
4616 | return -ENOMEM; | |
1da177e4 | 4617 | |
5a16f3d3 RR |
4618 | retval = get_user_cpu_mask(user_mask_ptr, len, new_mask); |
4619 | if (retval == 0) | |
4620 | retval = sched_setaffinity(pid, new_mask); | |
4621 | free_cpumask_var(new_mask); | |
4622 | return retval; | |
1da177e4 LT |
4623 | } |
4624 | ||
96f874e2 | 4625 | long sched_getaffinity(pid_t pid, struct cpumask *mask) |
1da177e4 | 4626 | { |
36c8b586 | 4627 | struct task_struct *p; |
31605683 | 4628 | unsigned long flags; |
1da177e4 | 4629 | int retval; |
1da177e4 | 4630 | |
23f5d142 | 4631 | rcu_read_lock(); |
1da177e4 LT |
4632 | |
4633 | retval = -ESRCH; | |
4634 | p = find_process_by_pid(pid); | |
4635 | if (!p) | |
4636 | goto out_unlock; | |
4637 | ||
e7834f8f DQ |
4638 | retval = security_task_getscheduler(p); |
4639 | if (retval) | |
4640 | goto out_unlock; | |
4641 | ||
013fdb80 | 4642 | raw_spin_lock_irqsave(&p->pi_lock, flags); |
6acce3ef | 4643 | cpumask_and(mask, &p->cpus_allowed, cpu_active_mask); |
013fdb80 | 4644 | raw_spin_unlock_irqrestore(&p->pi_lock, flags); |
1da177e4 LT |
4645 | |
4646 | out_unlock: | |
23f5d142 | 4647 | rcu_read_unlock(); |
1da177e4 | 4648 | |
9531b62f | 4649 | return retval; |
1da177e4 LT |
4650 | } |
4651 | ||
4652 | /** | |
4653 | * sys_sched_getaffinity - get the cpu affinity of a process | |
4654 | * @pid: pid of the process | |
4655 | * @len: length in bytes of the bitmask pointed to by user_mask_ptr | |
4656 | * @user_mask_ptr: user-space pointer to hold the current cpu mask | |
e69f6186 YB |
4657 | * |
4658 | * Return: 0 on success. An error code otherwise. | |
1da177e4 | 4659 | */ |
5add95d4 HC |
4660 | SYSCALL_DEFINE3(sched_getaffinity, pid_t, pid, unsigned int, len, |
4661 | unsigned long __user *, user_mask_ptr) | |
1da177e4 LT |
4662 | { |
4663 | int ret; | |
f17c8607 | 4664 | cpumask_var_t mask; |
1da177e4 | 4665 | |
84fba5ec | 4666 | if ((len * BITS_PER_BYTE) < nr_cpu_ids) |
cd3d8031 KM |
4667 | return -EINVAL; |
4668 | if (len & (sizeof(unsigned long)-1)) | |
1da177e4 LT |
4669 | return -EINVAL; |
4670 | ||
f17c8607 RR |
4671 | if (!alloc_cpumask_var(&mask, GFP_KERNEL)) |
4672 | return -ENOMEM; | |
1da177e4 | 4673 | |
f17c8607 RR |
4674 | ret = sched_getaffinity(pid, mask); |
4675 | if (ret == 0) { | |
8bc037fb | 4676 | size_t retlen = min_t(size_t, len, cpumask_size()); |
cd3d8031 KM |
4677 | |
4678 | if (copy_to_user(user_mask_ptr, mask, retlen)) | |
f17c8607 RR |
4679 | ret = -EFAULT; |
4680 | else | |
cd3d8031 | 4681 | ret = retlen; |
f17c8607 RR |
4682 | } |
4683 | free_cpumask_var(mask); | |
1da177e4 | 4684 | |
f17c8607 | 4685 | return ret; |
1da177e4 LT |
4686 | } |
4687 | ||
4688 | /** | |
4689 | * sys_sched_yield - yield the current processor to other threads. | |
4690 | * | |
dd41f596 IM |
4691 | * This function yields the current CPU to other tasks. If there are no |
4692 | * other threads running on this CPU then this function will return. | |
e69f6186 YB |
4693 | * |
4694 | * Return: 0. | |
1da177e4 | 4695 | */ |
5add95d4 | 4696 | SYSCALL_DEFINE0(sched_yield) |
1da177e4 | 4697 | { |
70b97a7f | 4698 | struct rq *rq = this_rq_lock(); |
1da177e4 | 4699 | |
2d72376b | 4700 | schedstat_inc(rq, yld_count); |
4530d7ab | 4701 | current->sched_class->yield_task(rq); |
1da177e4 LT |
4702 | |
4703 | /* | |
4704 | * Since we are going to call schedule() anyway, there's | |
4705 | * no need to preempt or enable interrupts: | |
4706 | */ | |
4707 | __release(rq->lock); | |
8a25d5de | 4708 | spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
9828ea9d | 4709 | do_raw_spin_unlock(&rq->lock); |
ba74c144 | 4710 | sched_preempt_enable_no_resched(); |
1da177e4 LT |
4711 | |
4712 | schedule(); | |
4713 | ||
4714 | return 0; | |
4715 | } | |
4716 | ||
02b67cc3 | 4717 | int __sched _cond_resched(void) |
1da177e4 | 4718 | { |
fe32d3cd | 4719 | if (should_resched(0)) { |
a18b5d01 | 4720 | preempt_schedule_common(); |
1da177e4 LT |
4721 | return 1; |
4722 | } | |
4723 | return 0; | |
4724 | } | |
02b67cc3 | 4725 | EXPORT_SYMBOL(_cond_resched); |
1da177e4 LT |
4726 | |
4727 | /* | |
613afbf8 | 4728 | * __cond_resched_lock() - if a reschedule is pending, drop the given lock, |
1da177e4 LT |
4729 | * call schedule, and on return reacquire the lock. |
4730 | * | |
41a2d6cf | 4731 | * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
1da177e4 LT |
4732 | * operations here to prevent schedule() from being called twice (once via |
4733 | * spin_unlock(), once by hand). | |
4734 | */ | |
613afbf8 | 4735 | int __cond_resched_lock(spinlock_t *lock) |
1da177e4 | 4736 | { |
fe32d3cd | 4737 | int resched = should_resched(PREEMPT_LOCK_OFFSET); |
6df3cecb JK |
4738 | int ret = 0; |
4739 | ||
f607c668 PZ |
4740 | lockdep_assert_held(lock); |
4741 | ||
4a81e832 | 4742 | if (spin_needbreak(lock) || resched) { |
1da177e4 | 4743 | spin_unlock(lock); |
d86ee480 | 4744 | if (resched) |
a18b5d01 | 4745 | preempt_schedule_common(); |
95c354fe NP |
4746 | else |
4747 | cpu_relax(); | |
6df3cecb | 4748 | ret = 1; |
1da177e4 | 4749 | spin_lock(lock); |
1da177e4 | 4750 | } |
6df3cecb | 4751 | return ret; |
1da177e4 | 4752 | } |
613afbf8 | 4753 | EXPORT_SYMBOL(__cond_resched_lock); |
1da177e4 | 4754 | |
613afbf8 | 4755 | int __sched __cond_resched_softirq(void) |
1da177e4 LT |
4756 | { |
4757 | BUG_ON(!in_softirq()); | |
4758 | ||
fe32d3cd | 4759 | if (should_resched(SOFTIRQ_DISABLE_OFFSET)) { |
98d82567 | 4760 | local_bh_enable(); |
a18b5d01 | 4761 | preempt_schedule_common(); |
1da177e4 LT |
4762 | local_bh_disable(); |
4763 | return 1; | |
4764 | } | |
4765 | return 0; | |
4766 | } | |
613afbf8 | 4767 | EXPORT_SYMBOL(__cond_resched_softirq); |
1da177e4 | 4768 | |
1da177e4 LT |
4769 | /** |
4770 | * yield - yield the current processor to other threads. | |
4771 | * | |
8e3fabfd PZ |
4772 | * Do not ever use this function, there's a 99% chance you're doing it wrong. |
4773 | * | |
4774 | * The scheduler is at all times free to pick the calling task as the most | |
4775 | * eligible task to run, if removing the yield() call from your code breaks | |
4776 | * it, its already broken. | |
4777 | * | |
4778 | * Typical broken usage is: | |
4779 | * | |
4780 | * while (!event) | |
4781 | * yield(); | |
4782 | * | |
4783 | * where one assumes that yield() will let 'the other' process run that will | |
4784 | * make event true. If the current task is a SCHED_FIFO task that will never | |
4785 | * happen. Never use yield() as a progress guarantee!! | |
4786 | * | |
4787 | * If you want to use yield() to wait for something, use wait_event(). | |
4788 | * If you want to use yield() to be 'nice' for others, use cond_resched(). | |
4789 | * If you still want to use yield(), do not! | |
1da177e4 LT |
4790 | */ |
4791 | void __sched yield(void) | |
4792 | { | |
4793 | set_current_state(TASK_RUNNING); | |
4794 | sys_sched_yield(); | |
4795 | } | |
1da177e4 LT |
4796 | EXPORT_SYMBOL(yield); |
4797 | ||
d95f4122 MG |
4798 | /** |
4799 | * yield_to - yield the current processor to another thread in | |
4800 | * your thread group, or accelerate that thread toward the | |
4801 | * processor it's on. | |
16addf95 RD |
4802 | * @p: target task |
4803 | * @preempt: whether task preemption is allowed or not | |
d95f4122 MG |
4804 | * |
4805 | * It's the caller's job to ensure that the target task struct | |
4806 | * can't go away on us before we can do any checks. | |
4807 | * | |
e69f6186 | 4808 | * Return: |
7b270f60 PZ |
4809 | * true (>0) if we indeed boosted the target task. |
4810 | * false (0) if we failed to boost the target. | |
4811 | * -ESRCH if there's no task to yield to. | |
d95f4122 | 4812 | */ |
fa93384f | 4813 | int __sched yield_to(struct task_struct *p, bool preempt) |
d95f4122 MG |
4814 | { |
4815 | struct task_struct *curr = current; | |
4816 | struct rq *rq, *p_rq; | |
4817 | unsigned long flags; | |
c3c18640 | 4818 | int yielded = 0; |
d95f4122 MG |
4819 | |
4820 | local_irq_save(flags); | |
4821 | rq = this_rq(); | |
4822 | ||
4823 | again: | |
4824 | p_rq = task_rq(p); | |
7b270f60 PZ |
4825 | /* |
4826 | * If we're the only runnable task on the rq and target rq also | |
4827 | * has only one task, there's absolutely no point in yielding. | |
4828 | */ | |
4829 | if (rq->nr_running == 1 && p_rq->nr_running == 1) { | |
4830 | yielded = -ESRCH; | |
4831 | goto out_irq; | |
4832 | } | |
4833 | ||
d95f4122 | 4834 | double_rq_lock(rq, p_rq); |
39e24d8f | 4835 | if (task_rq(p) != p_rq) { |
d95f4122 MG |
4836 | double_rq_unlock(rq, p_rq); |
4837 | goto again; | |
4838 | } | |
4839 | ||
4840 | if (!curr->sched_class->yield_to_task) | |
7b270f60 | 4841 | goto out_unlock; |
d95f4122 MG |
4842 | |
4843 | if (curr->sched_class != p->sched_class) | |
7b270f60 | 4844 | goto out_unlock; |
d95f4122 MG |
4845 | |
4846 | if (task_running(p_rq, p) || p->state) | |
7b270f60 | 4847 | goto out_unlock; |
d95f4122 MG |
4848 | |
4849 | yielded = curr->sched_class->yield_to_task(rq, p, preempt); | |
6d1cafd8 | 4850 | if (yielded) { |
d95f4122 | 4851 | schedstat_inc(rq, yld_count); |
6d1cafd8 VP |
4852 | /* |
4853 | * Make p's CPU reschedule; pick_next_entity takes care of | |
4854 | * fairness. | |
4855 | */ | |
4856 | if (preempt && rq != p_rq) | |
8875125e | 4857 | resched_curr(p_rq); |
6d1cafd8 | 4858 | } |
d95f4122 | 4859 | |
7b270f60 | 4860 | out_unlock: |
d95f4122 | 4861 | double_rq_unlock(rq, p_rq); |
7b270f60 | 4862 | out_irq: |
d95f4122 MG |
4863 | local_irq_restore(flags); |
4864 | ||
7b270f60 | 4865 | if (yielded > 0) |
d95f4122 MG |
4866 | schedule(); |
4867 | ||
4868 | return yielded; | |
4869 | } | |
4870 | EXPORT_SYMBOL_GPL(yield_to); | |
4871 | ||
1da177e4 | 4872 | /* |
41a2d6cf | 4873 | * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
1da177e4 | 4874 | * that process accounting knows that this is a task in IO wait state. |
1da177e4 | 4875 | */ |
1da177e4 LT |
4876 | long __sched io_schedule_timeout(long timeout) |
4877 | { | |
9cff8ade N |
4878 | int old_iowait = current->in_iowait; |
4879 | struct rq *rq; | |
1da177e4 LT |
4880 | long ret; |
4881 | ||
9cff8ade | 4882 | current->in_iowait = 1; |
10d784ea | 4883 | blk_schedule_flush_plug(current); |
9cff8ade | 4884 | |
0ff92245 | 4885 | delayacct_blkio_start(); |
9cff8ade | 4886 | rq = raw_rq(); |
1da177e4 LT |
4887 | atomic_inc(&rq->nr_iowait); |
4888 | ret = schedule_timeout(timeout); | |
9cff8ade | 4889 | current->in_iowait = old_iowait; |
1da177e4 | 4890 | atomic_dec(&rq->nr_iowait); |
0ff92245 | 4891 | delayacct_blkio_end(); |
9cff8ade | 4892 | |
1da177e4 LT |
4893 | return ret; |
4894 | } | |
9cff8ade | 4895 | EXPORT_SYMBOL(io_schedule_timeout); |
1da177e4 LT |
4896 | |
4897 | /** | |
4898 | * sys_sched_get_priority_max - return maximum RT priority. | |
4899 | * @policy: scheduling class. | |
4900 | * | |
e69f6186 YB |
4901 | * Return: On success, this syscall returns the maximum |
4902 | * rt_priority that can be used by a given scheduling class. | |
4903 | * On failure, a negative error code is returned. | |
1da177e4 | 4904 | */ |
5add95d4 | 4905 | SYSCALL_DEFINE1(sched_get_priority_max, int, policy) |
1da177e4 LT |
4906 | { |
4907 | int ret = -EINVAL; | |
4908 | ||
4909 | switch (policy) { | |
4910 | case SCHED_FIFO: | |
4911 | case SCHED_RR: | |
4912 | ret = MAX_USER_RT_PRIO-1; | |
4913 | break; | |
aab03e05 | 4914 | case SCHED_DEADLINE: |
1da177e4 | 4915 | case SCHED_NORMAL: |
b0a9499c | 4916 | case SCHED_BATCH: |
dd41f596 | 4917 | case SCHED_IDLE: |
1da177e4 LT |
4918 | ret = 0; |
4919 | break; | |
4920 | } | |
4921 | return ret; | |
4922 | } | |
4923 | ||
4924 | /** | |
4925 | * sys_sched_get_priority_min - return minimum RT priority. | |
4926 | * @policy: scheduling class. | |
4927 | * | |
e69f6186 YB |
4928 | * Return: On success, this syscall returns the minimum |
4929 | * rt_priority that can be used by a given scheduling class. | |
4930 | * On failure, a negative error code is returned. | |
1da177e4 | 4931 | */ |
5add95d4 | 4932 | SYSCALL_DEFINE1(sched_get_priority_min, int, policy) |
1da177e4 LT |
4933 | { |
4934 | int ret = -EINVAL; | |
4935 | ||
4936 | switch (policy) { | |
4937 | case SCHED_FIFO: | |
4938 | case SCHED_RR: | |
4939 | ret = 1; | |
4940 | break; | |
aab03e05 | 4941 | case SCHED_DEADLINE: |
1da177e4 | 4942 | case SCHED_NORMAL: |
b0a9499c | 4943 | case SCHED_BATCH: |
dd41f596 | 4944 | case SCHED_IDLE: |
1da177e4 LT |
4945 | ret = 0; |
4946 | } | |
4947 | return ret; | |
4948 | } | |
4949 | ||
4950 | /** | |
4951 | * sys_sched_rr_get_interval - return the default timeslice of a process. | |
4952 | * @pid: pid of the process. | |
4953 | * @interval: userspace pointer to the timeslice value. | |
4954 | * | |
4955 | * this syscall writes the default timeslice value of a given process | |
4956 | * into the user-space timespec buffer. A value of '0' means infinity. | |
e69f6186 YB |
4957 | * |
4958 | * Return: On success, 0 and the timeslice is in @interval. Otherwise, | |
4959 | * an error code. | |
1da177e4 | 4960 | */ |
17da2bd9 | 4961 | SYSCALL_DEFINE2(sched_rr_get_interval, pid_t, pid, |
754fe8d2 | 4962 | struct timespec __user *, interval) |
1da177e4 | 4963 | { |
36c8b586 | 4964 | struct task_struct *p; |
a4ec24b4 | 4965 | unsigned int time_slice; |
dba091b9 TG |
4966 | unsigned long flags; |
4967 | struct rq *rq; | |
3a5c359a | 4968 | int retval; |
1da177e4 | 4969 | struct timespec t; |
1da177e4 LT |
4970 | |
4971 | if (pid < 0) | |
3a5c359a | 4972 | return -EINVAL; |
1da177e4 LT |
4973 | |
4974 | retval = -ESRCH; | |
1a551ae7 | 4975 | rcu_read_lock(); |
1da177e4 LT |
4976 | p = find_process_by_pid(pid); |
4977 | if (!p) | |
4978 | goto out_unlock; | |
4979 | ||
4980 | retval = security_task_getscheduler(p); | |
4981 | if (retval) | |
4982 | goto out_unlock; | |
4983 | ||
dba091b9 | 4984 | rq = task_rq_lock(p, &flags); |
a57beec5 PZ |
4985 | time_slice = 0; |
4986 | if (p->sched_class->get_rr_interval) | |
4987 | time_slice = p->sched_class->get_rr_interval(rq, p); | |
0122ec5b | 4988 | task_rq_unlock(rq, p, &flags); |
a4ec24b4 | 4989 | |
1a551ae7 | 4990 | rcu_read_unlock(); |
a4ec24b4 | 4991 | jiffies_to_timespec(time_slice, &t); |
1da177e4 | 4992 | retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
1da177e4 | 4993 | return retval; |
3a5c359a | 4994 | |
1da177e4 | 4995 | out_unlock: |
1a551ae7 | 4996 | rcu_read_unlock(); |
1da177e4 LT |
4997 | return retval; |
4998 | } | |
4999 | ||
7c731e0a | 5000 | static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
36c8b586 | 5001 | |
82a1fcb9 | 5002 | void sched_show_task(struct task_struct *p) |
1da177e4 | 5003 | { |
1da177e4 | 5004 | unsigned long free = 0; |
4e79752c | 5005 | int ppid; |
1f8a7633 | 5006 | unsigned long state = p->state; |
1da177e4 | 5007 | |
1f8a7633 TH |
5008 | if (state) |
5009 | state = __ffs(state) + 1; | |
28d0686c | 5010 | printk(KERN_INFO "%-15.15s %c", p->comm, |
2ed6e34f | 5011 | state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
4bd77321 | 5012 | #if BITS_PER_LONG == 32 |
1da177e4 | 5013 | if (state == TASK_RUNNING) |
3df0fc5b | 5014 | printk(KERN_CONT " running "); |
1da177e4 | 5015 | else |
3df0fc5b | 5016 | printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
1da177e4 LT |
5017 | #else |
5018 | if (state == TASK_RUNNING) | |
3df0fc5b | 5019 | printk(KERN_CONT " running task "); |
1da177e4 | 5020 | else |
3df0fc5b | 5021 | printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
1da177e4 LT |
5022 | #endif |
5023 | #ifdef CONFIG_DEBUG_STACK_USAGE | |
7c9f8861 | 5024 | free = stack_not_used(p); |
1da177e4 | 5025 | #endif |
a90e984c | 5026 | ppid = 0; |
4e79752c | 5027 | rcu_read_lock(); |
a90e984c ON |
5028 | if (pid_alive(p)) |
5029 | ppid = task_pid_nr(rcu_dereference(p->real_parent)); | |
4e79752c | 5030 | rcu_read_unlock(); |
3df0fc5b | 5031 | printk(KERN_CONT "%5lu %5d %6d 0x%08lx\n", free, |
4e79752c | 5032 | task_pid_nr(p), ppid, |
aa47b7e0 | 5033 | (unsigned long)task_thread_info(p)->flags); |
1da177e4 | 5034 | |
3d1cb205 | 5035 | print_worker_info(KERN_INFO, p); |
5fb5e6de | 5036 | show_stack(p, NULL); |
1da177e4 LT |
5037 | } |
5038 | ||
e59e2ae2 | 5039 | void show_state_filter(unsigned long state_filter) |
1da177e4 | 5040 | { |
36c8b586 | 5041 | struct task_struct *g, *p; |
1da177e4 | 5042 | |
4bd77321 | 5043 | #if BITS_PER_LONG == 32 |
3df0fc5b PZ |
5044 | printk(KERN_INFO |
5045 | " task PC stack pid father\n"); | |
1da177e4 | 5046 | #else |
3df0fc5b PZ |
5047 | printk(KERN_INFO |
5048 | " task PC stack pid father\n"); | |
1da177e4 | 5049 | #endif |
510f5acc | 5050 | rcu_read_lock(); |
5d07f420 | 5051 | for_each_process_thread(g, p) { |
1da177e4 LT |
5052 | /* |
5053 | * reset the NMI-timeout, listing all files on a slow | |
25985edc | 5054 | * console might take a lot of time: |
1da177e4 LT |
5055 | */ |
5056 | touch_nmi_watchdog(); | |
39bc89fd | 5057 | if (!state_filter || (p->state & state_filter)) |
82a1fcb9 | 5058 | sched_show_task(p); |
5d07f420 | 5059 | } |
1da177e4 | 5060 | |
04c9167f JF |
5061 | touch_all_softlockup_watchdogs(); |
5062 | ||
dd41f596 IM |
5063 | #ifdef CONFIG_SCHED_DEBUG |
5064 | sysrq_sched_debug_show(); | |
5065 | #endif | |
510f5acc | 5066 | rcu_read_unlock(); |
e59e2ae2 IM |
5067 | /* |
5068 | * Only show locks if all tasks are dumped: | |
5069 | */ | |
93335a21 | 5070 | if (!state_filter) |
e59e2ae2 | 5071 | debug_show_all_locks(); |
1da177e4 LT |
5072 | } |
5073 | ||
0db0628d | 5074 | void init_idle_bootup_task(struct task_struct *idle) |
1df21055 | 5075 | { |
dd41f596 | 5076 | idle->sched_class = &idle_sched_class; |
1df21055 IM |
5077 | } |
5078 | ||
f340c0d1 IM |
5079 | /** |
5080 | * init_idle - set up an idle thread for a given CPU | |
5081 | * @idle: task in question | |
5082 | * @cpu: cpu the idle task belongs to | |
5083 | * | |
5084 | * NOTE: this function does not set the idle thread's NEED_RESCHED | |
5085 | * flag, to make booting more robust. | |
5086 | */ | |
0db0628d | 5087 | void init_idle(struct task_struct *idle, int cpu) |
1da177e4 | 5088 | { |
70b97a7f | 5089 | struct rq *rq = cpu_rq(cpu); |
1da177e4 LT |
5090 | unsigned long flags; |
5091 | ||
25834c73 PZ |
5092 | raw_spin_lock_irqsave(&idle->pi_lock, flags); |
5093 | raw_spin_lock(&rq->lock); | |
5cbd54ef | 5094 | |
5e1576ed | 5095 | __sched_fork(0, idle); |
06b83b5f | 5096 | idle->state = TASK_RUNNING; |
dd41f596 IM |
5097 | idle->se.exec_start = sched_clock(); |
5098 | ||
de9b8f5d PZ |
5099 | #ifdef CONFIG_SMP |
5100 | /* | |
5101 | * Its possible that init_idle() gets called multiple times on a task, | |
5102 | * in that case do_set_cpus_allowed() will not do the right thing. | |
5103 | * | |
5104 | * And since this is boot we can forgo the serialization. | |
5105 | */ | |
5106 | set_cpus_allowed_common(idle, cpumask_of(cpu)); | |
5107 | #endif | |
6506cf6c PZ |
5108 | /* |
5109 | * We're having a chicken and egg problem, even though we are | |
5110 | * holding rq->lock, the cpu isn't yet set to this cpu so the | |
5111 | * lockdep check in task_group() will fail. | |
5112 | * | |
5113 | * Similar case to sched_fork(). / Alternatively we could | |
5114 | * use task_rq_lock() here and obtain the other rq->lock. | |
5115 | * | |
5116 | * Silence PROVE_RCU | |
5117 | */ | |
5118 | rcu_read_lock(); | |
dd41f596 | 5119 | __set_task_cpu(idle, cpu); |
6506cf6c | 5120 | rcu_read_unlock(); |
1da177e4 | 5121 | |
1da177e4 | 5122 | rq->curr = rq->idle = idle; |
da0c1e65 | 5123 | idle->on_rq = TASK_ON_RQ_QUEUED; |
de9b8f5d | 5124 | #ifdef CONFIG_SMP |
3ca7a440 | 5125 | idle->on_cpu = 1; |
4866cde0 | 5126 | #endif |
25834c73 PZ |
5127 | raw_spin_unlock(&rq->lock); |
5128 | raw_spin_unlock_irqrestore(&idle->pi_lock, flags); | |
1da177e4 LT |
5129 | |
5130 | /* Set the preempt count _outside_ the spinlocks! */ | |
01028747 | 5131 | init_idle_preempt_count(idle, cpu); |
55cd5340 | 5132 | |
dd41f596 IM |
5133 | /* |
5134 | * The idle tasks have their own, simple scheduling class: | |
5135 | */ | |
5136 | idle->sched_class = &idle_sched_class; | |
868baf07 | 5137 | ftrace_graph_init_idle_task(idle, cpu); |
45eacc69 | 5138 | vtime_init_idle(idle, cpu); |
de9b8f5d | 5139 | #ifdef CONFIG_SMP |
f1c6f1a7 CE |
5140 | sprintf(idle->comm, "%s/%d", INIT_TASK_COMM, cpu); |
5141 | #endif | |
19978ca6 IM |
5142 | } |
5143 | ||
f82f8042 JL |
5144 | int cpuset_cpumask_can_shrink(const struct cpumask *cur, |
5145 | const struct cpumask *trial) | |
5146 | { | |
5147 | int ret = 1, trial_cpus; | |
5148 | struct dl_bw *cur_dl_b; | |
5149 | unsigned long flags; | |
5150 | ||
bb2bc55a MG |
5151 | if (!cpumask_weight(cur)) |
5152 | return ret; | |
5153 | ||
75e23e49 | 5154 | rcu_read_lock_sched(); |
f82f8042 JL |
5155 | cur_dl_b = dl_bw_of(cpumask_any(cur)); |
5156 | trial_cpus = cpumask_weight(trial); | |
5157 | ||
5158 | raw_spin_lock_irqsave(&cur_dl_b->lock, flags); | |
5159 | if (cur_dl_b->bw != -1 && | |
5160 | cur_dl_b->bw * trial_cpus < cur_dl_b->total_bw) | |
5161 | ret = 0; | |
5162 | raw_spin_unlock_irqrestore(&cur_dl_b->lock, flags); | |
75e23e49 | 5163 | rcu_read_unlock_sched(); |
f82f8042 JL |
5164 | |
5165 | return ret; | |
5166 | } | |
5167 | ||
7f51412a JL |
5168 | int task_can_attach(struct task_struct *p, |
5169 | const struct cpumask *cs_cpus_allowed) | |
5170 | { | |
5171 | int ret = 0; | |
5172 | ||
5173 | /* | |
5174 | * Kthreads which disallow setaffinity shouldn't be moved | |
5175 | * to a new cpuset; we don't want to change their cpu | |
5176 | * affinity and isolating such threads by their set of | |
5177 | * allowed nodes is unnecessary. Thus, cpusets are not | |
5178 | * applicable for such threads. This prevents checking for | |
5179 | * success of set_cpus_allowed_ptr() on all attached tasks | |
5180 | * before cpus_allowed may be changed. | |
5181 | */ | |
5182 | if (p->flags & PF_NO_SETAFFINITY) { | |
5183 | ret = -EINVAL; | |
5184 | goto out; | |
5185 | } | |
5186 | ||
5187 | #ifdef CONFIG_SMP | |
5188 | if (dl_task(p) && !cpumask_intersects(task_rq(p)->rd->span, | |
5189 | cs_cpus_allowed)) { | |
5190 | unsigned int dest_cpu = cpumask_any_and(cpu_active_mask, | |
5191 | cs_cpus_allowed); | |
75e23e49 | 5192 | struct dl_bw *dl_b; |
7f51412a JL |
5193 | bool overflow; |
5194 | int cpus; | |
5195 | unsigned long flags; | |
5196 | ||
75e23e49 JL |
5197 | rcu_read_lock_sched(); |
5198 | dl_b = dl_bw_of(dest_cpu); | |
7f51412a JL |
5199 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
5200 | cpus = dl_bw_cpus(dest_cpu); | |
5201 | overflow = __dl_overflow(dl_b, cpus, 0, p->dl.dl_bw); | |
5202 | if (overflow) | |
5203 | ret = -EBUSY; | |
5204 | else { | |
5205 | /* | |
5206 | * We reserve space for this task in the destination | |
5207 | * root_domain, as we can't fail after this point. | |
5208 | * We will free resources in the source root_domain | |
5209 | * later on (see set_cpus_allowed_dl()). | |
5210 | */ | |
5211 | __dl_add(dl_b, p->dl.dl_bw); | |
5212 | } | |
5213 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
75e23e49 | 5214 | rcu_read_unlock_sched(); |
7f51412a JL |
5215 | |
5216 | } | |
5217 | #endif | |
5218 | out: | |
5219 | return ret; | |
5220 | } | |
5221 | ||
1da177e4 | 5222 | #ifdef CONFIG_SMP |
1da177e4 | 5223 | |
e6628d5b MG |
5224 | #ifdef CONFIG_NUMA_BALANCING |
5225 | /* Migrate current task p to target_cpu */ | |
5226 | int migrate_task_to(struct task_struct *p, int target_cpu) | |
5227 | { | |
5228 | struct migration_arg arg = { p, target_cpu }; | |
5229 | int curr_cpu = task_cpu(p); | |
5230 | ||
5231 | if (curr_cpu == target_cpu) | |
5232 | return 0; | |
5233 | ||
5234 | if (!cpumask_test_cpu(target_cpu, tsk_cpus_allowed(p))) | |
5235 | return -EINVAL; | |
5236 | ||
5237 | /* TODO: This is not properly updating schedstats */ | |
5238 | ||
286549dc | 5239 | trace_sched_move_numa(p, curr_cpu, target_cpu); |
e6628d5b MG |
5240 | return stop_one_cpu(curr_cpu, migration_cpu_stop, &arg); |
5241 | } | |
0ec8aa00 PZ |
5242 | |
5243 | /* | |
5244 | * Requeue a task on a given node and accurately track the number of NUMA | |
5245 | * tasks on the runqueues | |
5246 | */ | |
5247 | void sched_setnuma(struct task_struct *p, int nid) | |
5248 | { | |
5249 | struct rq *rq; | |
5250 | unsigned long flags; | |
da0c1e65 | 5251 | bool queued, running; |
0ec8aa00 PZ |
5252 | |
5253 | rq = task_rq_lock(p, &flags); | |
da0c1e65 | 5254 | queued = task_on_rq_queued(p); |
0ec8aa00 PZ |
5255 | running = task_current(rq, p); |
5256 | ||
da0c1e65 | 5257 | if (queued) |
1de64443 | 5258 | dequeue_task(rq, p, DEQUEUE_SAVE); |
0ec8aa00 | 5259 | if (running) |
f3cd1c4e | 5260 | put_prev_task(rq, p); |
0ec8aa00 PZ |
5261 | |
5262 | p->numa_preferred_nid = nid; | |
0ec8aa00 PZ |
5263 | |
5264 | if (running) | |
5265 | p->sched_class->set_curr_task(rq); | |
da0c1e65 | 5266 | if (queued) |
1de64443 | 5267 | enqueue_task(rq, p, ENQUEUE_RESTORE); |
0ec8aa00 PZ |
5268 | task_rq_unlock(rq, p, &flags); |
5269 | } | |
5cc389bc | 5270 | #endif /* CONFIG_NUMA_BALANCING */ |
f7b4cddc | 5271 | |
1da177e4 | 5272 | #ifdef CONFIG_HOTPLUG_CPU |
054b9108 | 5273 | /* |
48c5ccae PZ |
5274 | * Ensures that the idle task is using init_mm right before its cpu goes |
5275 | * offline. | |
054b9108 | 5276 | */ |
48c5ccae | 5277 | void idle_task_exit(void) |
1da177e4 | 5278 | { |
48c5ccae | 5279 | struct mm_struct *mm = current->active_mm; |
e76bd8d9 | 5280 | |
48c5ccae | 5281 | BUG_ON(cpu_online(smp_processor_id())); |
e76bd8d9 | 5282 | |
a53efe5f | 5283 | if (mm != &init_mm) { |
48c5ccae | 5284 | switch_mm(mm, &init_mm, current); |
a53efe5f MS |
5285 | finish_arch_post_lock_switch(); |
5286 | } | |
48c5ccae | 5287 | mmdrop(mm); |
1da177e4 LT |
5288 | } |
5289 | ||
5290 | /* | |
5d180232 PZ |
5291 | * Since this CPU is going 'away' for a while, fold any nr_active delta |
5292 | * we might have. Assumes we're called after migrate_tasks() so that the | |
5293 | * nr_active count is stable. | |
5294 | * | |
5295 | * Also see the comment "Global load-average calculations". | |
1da177e4 | 5296 | */ |
5d180232 | 5297 | static void calc_load_migrate(struct rq *rq) |
1da177e4 | 5298 | { |
5d180232 PZ |
5299 | long delta = calc_load_fold_active(rq); |
5300 | if (delta) | |
5301 | atomic_long_add(delta, &calc_load_tasks); | |
1da177e4 LT |
5302 | } |
5303 | ||
3f1d2a31 PZ |
5304 | static void put_prev_task_fake(struct rq *rq, struct task_struct *prev) |
5305 | { | |
5306 | } | |
5307 | ||
5308 | static const struct sched_class fake_sched_class = { | |
5309 | .put_prev_task = put_prev_task_fake, | |
5310 | }; | |
5311 | ||
5312 | static struct task_struct fake_task = { | |
5313 | /* | |
5314 | * Avoid pull_{rt,dl}_task() | |
5315 | */ | |
5316 | .prio = MAX_PRIO + 1, | |
5317 | .sched_class = &fake_sched_class, | |
5318 | }; | |
5319 | ||
48f24c4d | 5320 | /* |
48c5ccae PZ |
5321 | * Migrate all tasks from the rq, sleeping tasks will be migrated by |
5322 | * try_to_wake_up()->select_task_rq(). | |
5323 | * | |
5324 | * Called with rq->lock held even though we'er in stop_machine() and | |
5325 | * there's no concurrency possible, we hold the required locks anyway | |
5326 | * because of lock validation efforts. | |
1da177e4 | 5327 | */ |
5e16bbc2 | 5328 | static void migrate_tasks(struct rq *dead_rq) |
1da177e4 | 5329 | { |
5e16bbc2 | 5330 | struct rq *rq = dead_rq; |
48c5ccae PZ |
5331 | struct task_struct *next, *stop = rq->stop; |
5332 | int dest_cpu; | |
1da177e4 LT |
5333 | |
5334 | /* | |
48c5ccae PZ |
5335 | * Fudge the rq selection such that the below task selection loop |
5336 | * doesn't get stuck on the currently eligible stop task. | |
5337 | * | |
5338 | * We're currently inside stop_machine() and the rq is either stuck | |
5339 | * in the stop_machine_cpu_stop() loop, or we're executing this code, | |
5340 | * either way we should never end up calling schedule() until we're | |
5341 | * done here. | |
1da177e4 | 5342 | */ |
48c5ccae | 5343 | rq->stop = NULL; |
48f24c4d | 5344 | |
77bd3970 FW |
5345 | /* |
5346 | * put_prev_task() and pick_next_task() sched | |
5347 | * class method both need to have an up-to-date | |
5348 | * value of rq->clock[_task] | |
5349 | */ | |
5350 | update_rq_clock(rq); | |
5351 | ||
5e16bbc2 | 5352 | for (;;) { |
48c5ccae PZ |
5353 | /* |
5354 | * There's this thread running, bail when that's the only | |
5355 | * remaining thread. | |
5356 | */ | |
5357 | if (rq->nr_running == 1) | |
dd41f596 | 5358 | break; |
48c5ccae | 5359 | |
cbce1a68 | 5360 | /* |
5473e0cc | 5361 | * pick_next_task assumes pinned rq->lock. |
cbce1a68 PZ |
5362 | */ |
5363 | lockdep_pin_lock(&rq->lock); | |
3f1d2a31 | 5364 | next = pick_next_task(rq, &fake_task); |
48c5ccae | 5365 | BUG_ON(!next); |
79c53799 | 5366 | next->sched_class->put_prev_task(rq, next); |
e692ab53 | 5367 | |
5473e0cc WL |
5368 | /* |
5369 | * Rules for changing task_struct::cpus_allowed are holding | |
5370 | * both pi_lock and rq->lock, such that holding either | |
5371 | * stabilizes the mask. | |
5372 | * | |
5373 | * Drop rq->lock is not quite as disastrous as it usually is | |
5374 | * because !cpu_active at this point, which means load-balance | |
5375 | * will not interfere. Also, stop-machine. | |
5376 | */ | |
5377 | lockdep_unpin_lock(&rq->lock); | |
5378 | raw_spin_unlock(&rq->lock); | |
5379 | raw_spin_lock(&next->pi_lock); | |
5380 | raw_spin_lock(&rq->lock); | |
5381 | ||
5382 | /* | |
5383 | * Since we're inside stop-machine, _nothing_ should have | |
5384 | * changed the task, WARN if weird stuff happened, because in | |
5385 | * that case the above rq->lock drop is a fail too. | |
5386 | */ | |
5387 | if (WARN_ON(task_rq(next) != rq || !task_on_rq_queued(next))) { | |
5388 | raw_spin_unlock(&next->pi_lock); | |
5389 | continue; | |
5390 | } | |
5391 | ||
48c5ccae | 5392 | /* Find suitable destination for @next, with force if needed. */ |
5e16bbc2 | 5393 | dest_cpu = select_fallback_rq(dead_rq->cpu, next); |
48c5ccae | 5394 | |
5e16bbc2 PZ |
5395 | rq = __migrate_task(rq, next, dest_cpu); |
5396 | if (rq != dead_rq) { | |
5397 | raw_spin_unlock(&rq->lock); | |
5398 | rq = dead_rq; | |
5399 | raw_spin_lock(&rq->lock); | |
5400 | } | |
5473e0cc | 5401 | raw_spin_unlock(&next->pi_lock); |
1da177e4 | 5402 | } |
dce48a84 | 5403 | |
48c5ccae | 5404 | rq->stop = stop; |
dce48a84 | 5405 | } |
1da177e4 LT |
5406 | #endif /* CONFIG_HOTPLUG_CPU */ |
5407 | ||
e692ab53 NP |
5408 | #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
5409 | ||
5410 | static struct ctl_table sd_ctl_dir[] = { | |
e0361851 AD |
5411 | { |
5412 | .procname = "sched_domain", | |
c57baf1e | 5413 | .mode = 0555, |
e0361851 | 5414 | }, |
56992309 | 5415 | {} |
e692ab53 NP |
5416 | }; |
5417 | ||
5418 | static struct ctl_table sd_ctl_root[] = { | |
e0361851 AD |
5419 | { |
5420 | .procname = "kernel", | |
c57baf1e | 5421 | .mode = 0555, |
e0361851 AD |
5422 | .child = sd_ctl_dir, |
5423 | }, | |
56992309 | 5424 | {} |
e692ab53 NP |
5425 | }; |
5426 | ||
5427 | static struct ctl_table *sd_alloc_ctl_entry(int n) | |
5428 | { | |
5429 | struct ctl_table *entry = | |
5cf9f062 | 5430 | kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
e692ab53 | 5431 | |
e692ab53 NP |
5432 | return entry; |
5433 | } | |
5434 | ||
6382bc90 MM |
5435 | static void sd_free_ctl_entry(struct ctl_table **tablep) |
5436 | { | |
cd790076 | 5437 | struct ctl_table *entry; |
6382bc90 | 5438 | |
cd790076 MM |
5439 | /* |
5440 | * In the intermediate directories, both the child directory and | |
5441 | * procname are dynamically allocated and could fail but the mode | |
41a2d6cf | 5442 | * will always be set. In the lowest directory the names are |
cd790076 MM |
5443 | * static strings and all have proc handlers. |
5444 | */ | |
5445 | for (entry = *tablep; entry->mode; entry++) { | |
6382bc90 MM |
5446 | if (entry->child) |
5447 | sd_free_ctl_entry(&entry->child); | |
cd790076 MM |
5448 | if (entry->proc_handler == NULL) |
5449 | kfree(entry->procname); | |
5450 | } | |
6382bc90 MM |
5451 | |
5452 | kfree(*tablep); | |
5453 | *tablep = NULL; | |
5454 | } | |
5455 | ||
201c373e | 5456 | static int min_load_idx = 0; |
fd9b86d3 | 5457 | static int max_load_idx = CPU_LOAD_IDX_MAX-1; |
201c373e | 5458 | |
e692ab53 | 5459 | static void |
e0361851 | 5460 | set_table_entry(struct ctl_table *entry, |
e692ab53 | 5461 | const char *procname, void *data, int maxlen, |
201c373e NK |
5462 | umode_t mode, proc_handler *proc_handler, |
5463 | bool load_idx) | |
e692ab53 | 5464 | { |
e692ab53 NP |
5465 | entry->procname = procname; |
5466 | entry->data = data; | |
5467 | entry->maxlen = maxlen; | |
5468 | entry->mode = mode; | |
5469 | entry->proc_handler = proc_handler; | |
201c373e NK |
5470 | |
5471 | if (load_idx) { | |
5472 | entry->extra1 = &min_load_idx; | |
5473 | entry->extra2 = &max_load_idx; | |
5474 | } | |
e692ab53 NP |
5475 | } |
5476 | ||
5477 | static struct ctl_table * | |
5478 | sd_alloc_ctl_domain_table(struct sched_domain *sd) | |
5479 | { | |
37e6bae8 | 5480 | struct ctl_table *table = sd_alloc_ctl_entry(14); |
e692ab53 | 5481 | |
ad1cdc1d MM |
5482 | if (table == NULL) |
5483 | return NULL; | |
5484 | ||
e0361851 | 5485 | set_table_entry(&table[0], "min_interval", &sd->min_interval, |
201c373e | 5486 | sizeof(long), 0644, proc_doulongvec_minmax, false); |
e0361851 | 5487 | set_table_entry(&table[1], "max_interval", &sd->max_interval, |
201c373e | 5488 | sizeof(long), 0644, proc_doulongvec_minmax, false); |
e0361851 | 5489 | set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
201c373e | 5490 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 5491 | set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
201c373e | 5492 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 5493 | set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
201c373e | 5494 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 5495 | set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
201c373e | 5496 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 5497 | set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
201c373e | 5498 | sizeof(int), 0644, proc_dointvec_minmax, true); |
e0361851 | 5499 | set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
201c373e | 5500 | sizeof(int), 0644, proc_dointvec_minmax, false); |
e0361851 | 5501 | set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
201c373e | 5502 | sizeof(int), 0644, proc_dointvec_minmax, false); |
ace8b3d6 | 5503 | set_table_entry(&table[9], "cache_nice_tries", |
e692ab53 | 5504 | &sd->cache_nice_tries, |
201c373e | 5505 | sizeof(int), 0644, proc_dointvec_minmax, false); |
ace8b3d6 | 5506 | set_table_entry(&table[10], "flags", &sd->flags, |
201c373e | 5507 | sizeof(int), 0644, proc_dointvec_minmax, false); |
37e6bae8 AS |
5508 | set_table_entry(&table[11], "max_newidle_lb_cost", |
5509 | &sd->max_newidle_lb_cost, | |
5510 | sizeof(long), 0644, proc_doulongvec_minmax, false); | |
5511 | set_table_entry(&table[12], "name", sd->name, | |
201c373e | 5512 | CORENAME_MAX_SIZE, 0444, proc_dostring, false); |
37e6bae8 | 5513 | /* &table[13] is terminator */ |
e692ab53 NP |
5514 | |
5515 | return table; | |
5516 | } | |
5517 | ||
be7002e6 | 5518 | static struct ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
e692ab53 NP |
5519 | { |
5520 | struct ctl_table *entry, *table; | |
5521 | struct sched_domain *sd; | |
5522 | int domain_num = 0, i; | |
5523 | char buf[32]; | |
5524 | ||
5525 | for_each_domain(cpu, sd) | |
5526 | domain_num++; | |
5527 | entry = table = sd_alloc_ctl_entry(domain_num + 1); | |
ad1cdc1d MM |
5528 | if (table == NULL) |
5529 | return NULL; | |
e692ab53 NP |
5530 | |
5531 | i = 0; | |
5532 | for_each_domain(cpu, sd) { | |
5533 | snprintf(buf, 32, "domain%d", i); | |
e692ab53 | 5534 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5535 | entry->mode = 0555; |
e692ab53 NP |
5536 | entry->child = sd_alloc_ctl_domain_table(sd); |
5537 | entry++; | |
5538 | i++; | |
5539 | } | |
5540 | return table; | |
5541 | } | |
5542 | ||
5543 | static struct ctl_table_header *sd_sysctl_header; | |
6382bc90 | 5544 | static void register_sched_domain_sysctl(void) |
e692ab53 | 5545 | { |
6ad4c188 | 5546 | int i, cpu_num = num_possible_cpus(); |
e692ab53 NP |
5547 | struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
5548 | char buf[32]; | |
5549 | ||
7378547f MM |
5550 | WARN_ON(sd_ctl_dir[0].child); |
5551 | sd_ctl_dir[0].child = entry; | |
5552 | ||
ad1cdc1d MM |
5553 | if (entry == NULL) |
5554 | return; | |
5555 | ||
6ad4c188 | 5556 | for_each_possible_cpu(i) { |
e692ab53 | 5557 | snprintf(buf, 32, "cpu%d", i); |
e692ab53 | 5558 | entry->procname = kstrdup(buf, GFP_KERNEL); |
c57baf1e | 5559 | entry->mode = 0555; |
e692ab53 | 5560 | entry->child = sd_alloc_ctl_cpu_table(i); |
97b6ea7b | 5561 | entry++; |
e692ab53 | 5562 | } |
7378547f MM |
5563 | |
5564 | WARN_ON(sd_sysctl_header); | |
e692ab53 NP |
5565 | sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
5566 | } | |
6382bc90 | 5567 | |
7378547f | 5568 | /* may be called multiple times per register */ |
6382bc90 MM |
5569 | static void unregister_sched_domain_sysctl(void) |
5570 | { | |
781b0203 | 5571 | unregister_sysctl_table(sd_sysctl_header); |
6382bc90 | 5572 | sd_sysctl_header = NULL; |
7378547f MM |
5573 | if (sd_ctl_dir[0].child) |
5574 | sd_free_ctl_entry(&sd_ctl_dir[0].child); | |
6382bc90 | 5575 | } |
e692ab53 | 5576 | #else |
6382bc90 MM |
5577 | static void register_sched_domain_sysctl(void) |
5578 | { | |
5579 | } | |
5580 | static void unregister_sched_domain_sysctl(void) | |
e692ab53 NP |
5581 | { |
5582 | } | |
5cc389bc | 5583 | #endif /* CONFIG_SCHED_DEBUG && CONFIG_SYSCTL */ |
e692ab53 | 5584 | |
1f11eb6a GH |
5585 | static void set_rq_online(struct rq *rq) |
5586 | { | |
5587 | if (!rq->online) { | |
5588 | const struct sched_class *class; | |
5589 | ||
c6c4927b | 5590 | cpumask_set_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
5591 | rq->online = 1; |
5592 | ||
5593 | for_each_class(class) { | |
5594 | if (class->rq_online) | |
5595 | class->rq_online(rq); | |
5596 | } | |
5597 | } | |
5598 | } | |
5599 | ||
5600 | static void set_rq_offline(struct rq *rq) | |
5601 | { | |
5602 | if (rq->online) { | |
5603 | const struct sched_class *class; | |
5604 | ||
5605 | for_each_class(class) { | |
5606 | if (class->rq_offline) | |
5607 | class->rq_offline(rq); | |
5608 | } | |
5609 | ||
c6c4927b | 5610 | cpumask_clear_cpu(rq->cpu, rq->rd->online); |
1f11eb6a GH |
5611 | rq->online = 0; |
5612 | } | |
5613 | } | |
5614 | ||
1da177e4 LT |
5615 | /* |
5616 | * migration_call - callback that gets triggered when a CPU is added. | |
5617 | * Here we can start up the necessary migration thread for the new CPU. | |
5618 | */ | |
0db0628d | 5619 | static int |
48f24c4d | 5620 | migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
1da177e4 | 5621 | { |
48f24c4d | 5622 | int cpu = (long)hcpu; |
1da177e4 | 5623 | unsigned long flags; |
969c7921 | 5624 | struct rq *rq = cpu_rq(cpu); |
1da177e4 | 5625 | |
48c5ccae | 5626 | switch (action & ~CPU_TASKS_FROZEN) { |
5be9361c | 5627 | |
1da177e4 | 5628 | case CPU_UP_PREPARE: |
a468d389 | 5629 | rq->calc_load_update = calc_load_update; |
1da177e4 | 5630 | break; |
48f24c4d | 5631 | |
1da177e4 | 5632 | case CPU_ONLINE: |
1f94ef59 | 5633 | /* Update our root-domain */ |
05fa785c | 5634 | raw_spin_lock_irqsave(&rq->lock, flags); |
1f94ef59 | 5635 | if (rq->rd) { |
c6c4927b | 5636 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
1f11eb6a GH |
5637 | |
5638 | set_rq_online(rq); | |
1f94ef59 | 5639 | } |
05fa785c | 5640 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
1da177e4 | 5641 | break; |
48f24c4d | 5642 | |
1da177e4 | 5643 | #ifdef CONFIG_HOTPLUG_CPU |
08f503b0 | 5644 | case CPU_DYING: |
317f3941 | 5645 | sched_ttwu_pending(); |
57d885fe | 5646 | /* Update our root-domain */ |
05fa785c | 5647 | raw_spin_lock_irqsave(&rq->lock, flags); |
57d885fe | 5648 | if (rq->rd) { |
c6c4927b | 5649 | BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); |
1f11eb6a | 5650 | set_rq_offline(rq); |
57d885fe | 5651 | } |
5e16bbc2 | 5652 | migrate_tasks(rq); |
48c5ccae | 5653 | BUG_ON(rq->nr_running != 1); /* the migration thread */ |
05fa785c | 5654 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
5d180232 | 5655 | break; |
48c5ccae | 5656 | |
5d180232 | 5657 | case CPU_DEAD: |
f319da0c | 5658 | calc_load_migrate(rq); |
57d885fe | 5659 | break; |
1da177e4 LT |
5660 | #endif |
5661 | } | |
49c022e6 PZ |
5662 | |
5663 | update_max_interval(); | |
5664 | ||
1da177e4 LT |
5665 | return NOTIFY_OK; |
5666 | } | |
5667 | ||
f38b0820 PM |
5668 | /* |
5669 | * Register at high priority so that task migration (migrate_all_tasks) | |
5670 | * happens before everything else. This has to be lower priority than | |
cdd6c482 | 5671 | * the notifier in the perf_event subsystem, though. |
1da177e4 | 5672 | */ |
0db0628d | 5673 | static struct notifier_block migration_notifier = { |
1da177e4 | 5674 | .notifier_call = migration_call, |
50a323b7 | 5675 | .priority = CPU_PRI_MIGRATION, |
1da177e4 LT |
5676 | }; |
5677 | ||
6a82b60d | 5678 | static void set_cpu_rq_start_time(void) |
a803f026 CM |
5679 | { |
5680 | int cpu = smp_processor_id(); | |
5681 | struct rq *rq = cpu_rq(cpu); | |
5682 | rq->age_stamp = sched_clock_cpu(cpu); | |
5683 | } | |
5684 | ||
0db0628d | 5685 | static int sched_cpu_active(struct notifier_block *nfb, |
3a101d05 TH |
5686 | unsigned long action, void *hcpu) |
5687 | { | |
07f06cb3 PZ |
5688 | int cpu = (long)hcpu; |
5689 | ||
3a101d05 | 5690 | switch (action & ~CPU_TASKS_FROZEN) { |
a803f026 CM |
5691 | case CPU_STARTING: |
5692 | set_cpu_rq_start_time(); | |
5693 | return NOTIFY_OK; | |
07f06cb3 | 5694 | |
dd9d3843 JS |
5695 | case CPU_ONLINE: |
5696 | /* | |
5697 | * At this point a starting CPU has marked itself as online via | |
5698 | * set_cpu_online(). But it might not yet have marked itself | |
5699 | * as active, which is essential from here on. | |
dd9d3843 | 5700 | */ |
07f06cb3 PZ |
5701 | set_cpu_active(cpu, true); |
5702 | stop_machine_unpark(cpu); | |
5703 | return NOTIFY_OK; | |
5704 | ||
3a101d05 | 5705 | case CPU_DOWN_FAILED: |
07f06cb3 | 5706 | set_cpu_active(cpu, true); |
3a101d05 | 5707 | return NOTIFY_OK; |
07f06cb3 | 5708 | |
3a101d05 TH |
5709 | default: |
5710 | return NOTIFY_DONE; | |
5711 | } | |
5712 | } | |
5713 | ||
0db0628d | 5714 | static int sched_cpu_inactive(struct notifier_block *nfb, |
3a101d05 TH |
5715 | unsigned long action, void *hcpu) |
5716 | { | |
5717 | switch (action & ~CPU_TASKS_FROZEN) { | |
5718 | case CPU_DOWN_PREPARE: | |
3c18d447 | 5719 | set_cpu_active((long)hcpu, false); |
3a101d05 | 5720 | return NOTIFY_OK; |
3c18d447 JL |
5721 | default: |
5722 | return NOTIFY_DONE; | |
3a101d05 TH |
5723 | } |
5724 | } | |
5725 | ||
7babe8db | 5726 | static int __init migration_init(void) |
1da177e4 LT |
5727 | { |
5728 | void *cpu = (void *)(long)smp_processor_id(); | |
07dccf33 | 5729 | int err; |
48f24c4d | 5730 | |
3a101d05 | 5731 | /* Initialize migration for the boot CPU */ |
07dccf33 AM |
5732 | err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
5733 | BUG_ON(err == NOTIFY_BAD); | |
1da177e4 LT |
5734 | migration_call(&migration_notifier, CPU_ONLINE, cpu); |
5735 | register_cpu_notifier(&migration_notifier); | |
7babe8db | 5736 | |
3a101d05 TH |
5737 | /* Register cpu active notifiers */ |
5738 | cpu_notifier(sched_cpu_active, CPU_PRI_SCHED_ACTIVE); | |
5739 | cpu_notifier(sched_cpu_inactive, CPU_PRI_SCHED_INACTIVE); | |
5740 | ||
a004cd42 | 5741 | return 0; |
1da177e4 | 5742 | } |
7babe8db | 5743 | early_initcall(migration_init); |
476f3534 | 5744 | |
4cb98839 PZ |
5745 | static cpumask_var_t sched_domains_tmpmask; /* sched_domains_mutex */ |
5746 | ||
3e9830dc | 5747 | #ifdef CONFIG_SCHED_DEBUG |
4dcf6aff | 5748 | |
d039ac60 | 5749 | static __read_mostly int sched_debug_enabled; |
f6630114 | 5750 | |
d039ac60 | 5751 | static int __init sched_debug_setup(char *str) |
f6630114 | 5752 | { |
d039ac60 | 5753 | sched_debug_enabled = 1; |
f6630114 MT |
5754 | |
5755 | return 0; | |
5756 | } | |
d039ac60 PZ |
5757 | early_param("sched_debug", sched_debug_setup); |
5758 | ||
5759 | static inline bool sched_debug(void) | |
5760 | { | |
5761 | return sched_debug_enabled; | |
5762 | } | |
f6630114 | 5763 | |
7c16ec58 | 5764 | static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
96f874e2 | 5765 | struct cpumask *groupmask) |
1da177e4 | 5766 | { |
4dcf6aff | 5767 | struct sched_group *group = sd->groups; |
1da177e4 | 5768 | |
96f874e2 | 5769 | cpumask_clear(groupmask); |
4dcf6aff IM |
5770 | |
5771 | printk(KERN_DEBUG "%*s domain %d: ", level, "", level); | |
5772 | ||
5773 | if (!(sd->flags & SD_LOAD_BALANCE)) { | |
3df0fc5b | 5774 | printk("does not load-balance\n"); |
4dcf6aff | 5775 | if (sd->parent) |
3df0fc5b PZ |
5776 | printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
5777 | " has parent"); | |
4dcf6aff | 5778 | return -1; |
41c7ce9a NP |
5779 | } |
5780 | ||
333470ee TH |
5781 | printk(KERN_CONT "span %*pbl level %s\n", |
5782 | cpumask_pr_args(sched_domain_span(sd)), sd->name); | |
4dcf6aff | 5783 | |
758b2cdc | 5784 | if (!cpumask_test_cpu(cpu, sched_domain_span(sd))) { |
3df0fc5b PZ |
5785 | printk(KERN_ERR "ERROR: domain->span does not contain " |
5786 | "CPU%d\n", cpu); | |
4dcf6aff | 5787 | } |
758b2cdc | 5788 | if (!cpumask_test_cpu(cpu, sched_group_cpus(group))) { |
3df0fc5b PZ |
5789 | printk(KERN_ERR "ERROR: domain->groups does not contain" |
5790 | " CPU%d\n", cpu); | |
4dcf6aff | 5791 | } |
1da177e4 | 5792 | |
4dcf6aff | 5793 | printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
1da177e4 | 5794 | do { |
4dcf6aff | 5795 | if (!group) { |
3df0fc5b PZ |
5796 | printk("\n"); |
5797 | printk(KERN_ERR "ERROR: group is NULL\n"); | |
1da177e4 LT |
5798 | break; |
5799 | } | |
5800 | ||
758b2cdc | 5801 | if (!cpumask_weight(sched_group_cpus(group))) { |
3df0fc5b PZ |
5802 | printk(KERN_CONT "\n"); |
5803 | printk(KERN_ERR "ERROR: empty group\n"); | |
4dcf6aff IM |
5804 | break; |
5805 | } | |
1da177e4 | 5806 | |
cb83b629 PZ |
5807 | if (!(sd->flags & SD_OVERLAP) && |
5808 | cpumask_intersects(groupmask, sched_group_cpus(group))) { | |
3df0fc5b PZ |
5809 | printk(KERN_CONT "\n"); |
5810 | printk(KERN_ERR "ERROR: repeated CPUs\n"); | |
4dcf6aff IM |
5811 | break; |
5812 | } | |
1da177e4 | 5813 | |
758b2cdc | 5814 | cpumask_or(groupmask, groupmask, sched_group_cpus(group)); |
1da177e4 | 5815 | |
333470ee TH |
5816 | printk(KERN_CONT " %*pbl", |
5817 | cpumask_pr_args(sched_group_cpus(group))); | |
ca8ce3d0 | 5818 | if (group->sgc->capacity != SCHED_CAPACITY_SCALE) { |
63b2ca30 NP |
5819 | printk(KERN_CONT " (cpu_capacity = %d)", |
5820 | group->sgc->capacity); | |
381512cf | 5821 | } |
1da177e4 | 5822 | |
4dcf6aff IM |
5823 | group = group->next; |
5824 | } while (group != sd->groups); | |
3df0fc5b | 5825 | printk(KERN_CONT "\n"); |
1da177e4 | 5826 | |
758b2cdc | 5827 | if (!cpumask_equal(sched_domain_span(sd), groupmask)) |
3df0fc5b | 5828 | printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
1da177e4 | 5829 | |
758b2cdc RR |
5830 | if (sd->parent && |
5831 | !cpumask_subset(groupmask, sched_domain_span(sd->parent))) | |
3df0fc5b PZ |
5832 | printk(KERN_ERR "ERROR: parent span is not a superset " |
5833 | "of domain->span\n"); | |
4dcf6aff IM |
5834 | return 0; |
5835 | } | |
1da177e4 | 5836 | |
4dcf6aff IM |
5837 | static void sched_domain_debug(struct sched_domain *sd, int cpu) |
5838 | { | |
5839 | int level = 0; | |
1da177e4 | 5840 | |
d039ac60 | 5841 | if (!sched_debug_enabled) |
f6630114 MT |
5842 | return; |
5843 | ||
4dcf6aff IM |
5844 | if (!sd) { |
5845 | printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); | |
5846 | return; | |
5847 | } | |
1da177e4 | 5848 | |
4dcf6aff IM |
5849 | printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
5850 | ||
5851 | for (;;) { | |
4cb98839 | 5852 | if (sched_domain_debug_one(sd, cpu, level, sched_domains_tmpmask)) |
4dcf6aff | 5853 | break; |
1da177e4 LT |
5854 | level++; |
5855 | sd = sd->parent; | |
33859f7f | 5856 | if (!sd) |
4dcf6aff IM |
5857 | break; |
5858 | } | |
1da177e4 | 5859 | } |
6d6bc0ad | 5860 | #else /* !CONFIG_SCHED_DEBUG */ |
48f24c4d | 5861 | # define sched_domain_debug(sd, cpu) do { } while (0) |
d039ac60 PZ |
5862 | static inline bool sched_debug(void) |
5863 | { | |
5864 | return false; | |
5865 | } | |
6d6bc0ad | 5866 | #endif /* CONFIG_SCHED_DEBUG */ |
1da177e4 | 5867 | |
1a20ff27 | 5868 | static int sd_degenerate(struct sched_domain *sd) |
245af2c7 | 5869 | { |
758b2cdc | 5870 | if (cpumask_weight(sched_domain_span(sd)) == 1) |
245af2c7 SS |
5871 | return 1; |
5872 | ||
5873 | /* Following flags need at least 2 groups */ | |
5874 | if (sd->flags & (SD_LOAD_BALANCE | | |
5875 | SD_BALANCE_NEWIDLE | | |
5876 | SD_BALANCE_FORK | | |
89c4710e | 5877 | SD_BALANCE_EXEC | |
5d4dfddd | 5878 | SD_SHARE_CPUCAPACITY | |
d77b3ed5 VG |
5879 | SD_SHARE_PKG_RESOURCES | |
5880 | SD_SHARE_POWERDOMAIN)) { | |
245af2c7 SS |
5881 | if (sd->groups != sd->groups->next) |
5882 | return 0; | |
5883 | } | |
5884 | ||
5885 | /* Following flags don't use groups */ | |
c88d5910 | 5886 | if (sd->flags & (SD_WAKE_AFFINE)) |
245af2c7 SS |
5887 | return 0; |
5888 | ||
5889 | return 1; | |
5890 | } | |
5891 | ||
48f24c4d IM |
5892 | static int |
5893 | sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) | |
245af2c7 SS |
5894 | { |
5895 | unsigned long cflags = sd->flags, pflags = parent->flags; | |
5896 | ||
5897 | if (sd_degenerate(parent)) | |
5898 | return 1; | |
5899 | ||
758b2cdc | 5900 | if (!cpumask_equal(sched_domain_span(sd), sched_domain_span(parent))) |
245af2c7 SS |
5901 | return 0; |
5902 | ||
245af2c7 SS |
5903 | /* Flags needing groups don't count if only 1 group in parent */ |
5904 | if (parent->groups == parent->groups->next) { | |
5905 | pflags &= ~(SD_LOAD_BALANCE | | |
5906 | SD_BALANCE_NEWIDLE | | |
5907 | SD_BALANCE_FORK | | |
89c4710e | 5908 | SD_BALANCE_EXEC | |
5d4dfddd | 5909 | SD_SHARE_CPUCAPACITY | |
10866e62 | 5910 | SD_SHARE_PKG_RESOURCES | |
d77b3ed5 VG |
5911 | SD_PREFER_SIBLING | |
5912 | SD_SHARE_POWERDOMAIN); | |
5436499e KC |
5913 | if (nr_node_ids == 1) |
5914 | pflags &= ~SD_SERIALIZE; | |
245af2c7 SS |
5915 | } |
5916 | if (~cflags & pflags) | |
5917 | return 0; | |
5918 | ||
5919 | return 1; | |
5920 | } | |
5921 | ||
dce840a0 | 5922 | static void free_rootdomain(struct rcu_head *rcu) |
c6c4927b | 5923 | { |
dce840a0 | 5924 | struct root_domain *rd = container_of(rcu, struct root_domain, rcu); |
047106ad | 5925 | |
68e74568 | 5926 | cpupri_cleanup(&rd->cpupri); |
6bfd6d72 | 5927 | cpudl_cleanup(&rd->cpudl); |
1baca4ce | 5928 | free_cpumask_var(rd->dlo_mask); |
c6c4927b RR |
5929 | free_cpumask_var(rd->rto_mask); |
5930 | free_cpumask_var(rd->online); | |
5931 | free_cpumask_var(rd->span); | |
5932 | kfree(rd); | |
5933 | } | |
5934 | ||
57d885fe GH |
5935 | static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
5936 | { | |
a0490fa3 | 5937 | struct root_domain *old_rd = NULL; |
57d885fe | 5938 | unsigned long flags; |
57d885fe | 5939 | |
05fa785c | 5940 | raw_spin_lock_irqsave(&rq->lock, flags); |
57d885fe GH |
5941 | |
5942 | if (rq->rd) { | |
a0490fa3 | 5943 | old_rd = rq->rd; |
57d885fe | 5944 | |
c6c4927b | 5945 | if (cpumask_test_cpu(rq->cpu, old_rd->online)) |
1f11eb6a | 5946 | set_rq_offline(rq); |
57d885fe | 5947 | |
c6c4927b | 5948 | cpumask_clear_cpu(rq->cpu, old_rd->span); |
dc938520 | 5949 | |
a0490fa3 | 5950 | /* |
0515973f | 5951 | * If we dont want to free the old_rd yet then |
a0490fa3 IM |
5952 | * set old_rd to NULL to skip the freeing later |
5953 | * in this function: | |
5954 | */ | |
5955 | if (!atomic_dec_and_test(&old_rd->refcount)) | |
5956 | old_rd = NULL; | |
57d885fe GH |
5957 | } |
5958 | ||
5959 | atomic_inc(&rd->refcount); | |
5960 | rq->rd = rd; | |
5961 | ||
c6c4927b | 5962 | cpumask_set_cpu(rq->cpu, rd->span); |
00aec93d | 5963 | if (cpumask_test_cpu(rq->cpu, cpu_active_mask)) |
1f11eb6a | 5964 | set_rq_online(rq); |
57d885fe | 5965 | |
05fa785c | 5966 | raw_spin_unlock_irqrestore(&rq->lock, flags); |
a0490fa3 IM |
5967 | |
5968 | if (old_rd) | |
dce840a0 | 5969 | call_rcu_sched(&old_rd->rcu, free_rootdomain); |
57d885fe GH |
5970 | } |
5971 | ||
68c38fc3 | 5972 | static int init_rootdomain(struct root_domain *rd) |
57d885fe GH |
5973 | { |
5974 | memset(rd, 0, sizeof(*rd)); | |
5975 | ||
8295c699 | 5976 | if (!zalloc_cpumask_var(&rd->span, GFP_KERNEL)) |
0c910d28 | 5977 | goto out; |
8295c699 | 5978 | if (!zalloc_cpumask_var(&rd->online, GFP_KERNEL)) |
c6c4927b | 5979 | goto free_span; |
8295c699 | 5980 | if (!zalloc_cpumask_var(&rd->dlo_mask, GFP_KERNEL)) |
c6c4927b | 5981 | goto free_online; |
8295c699 | 5982 | if (!zalloc_cpumask_var(&rd->rto_mask, GFP_KERNEL)) |
1baca4ce | 5983 | goto free_dlo_mask; |
6e0534f2 | 5984 | |
332ac17e | 5985 | init_dl_bw(&rd->dl_bw); |
6bfd6d72 JL |
5986 | if (cpudl_init(&rd->cpudl) != 0) |
5987 | goto free_dlo_mask; | |
332ac17e | 5988 | |
68c38fc3 | 5989 | if (cpupri_init(&rd->cpupri) != 0) |
68e74568 | 5990 | goto free_rto_mask; |
c6c4927b | 5991 | return 0; |
6e0534f2 | 5992 | |
68e74568 RR |
5993 | free_rto_mask: |
5994 | free_cpumask_var(rd->rto_mask); | |
1baca4ce JL |
5995 | free_dlo_mask: |
5996 | free_cpumask_var(rd->dlo_mask); | |
c6c4927b RR |
5997 | free_online: |
5998 | free_cpumask_var(rd->online); | |
5999 | free_span: | |
6000 | free_cpumask_var(rd->span); | |
0c910d28 | 6001 | out: |
c6c4927b | 6002 | return -ENOMEM; |
57d885fe GH |
6003 | } |
6004 | ||
029632fb PZ |
6005 | /* |
6006 | * By default the system creates a single root-domain with all cpus as | |
6007 | * members (mimicking the global state we have today). | |
6008 | */ | |
6009 | struct root_domain def_root_domain; | |
6010 | ||
57d885fe GH |
6011 | static void init_defrootdomain(void) |
6012 | { | |
68c38fc3 | 6013 | init_rootdomain(&def_root_domain); |
c6c4927b | 6014 | |
57d885fe GH |
6015 | atomic_set(&def_root_domain.refcount, 1); |
6016 | } | |
6017 | ||
dc938520 | 6018 | static struct root_domain *alloc_rootdomain(void) |
57d885fe GH |
6019 | { |
6020 | struct root_domain *rd; | |
6021 | ||
6022 | rd = kmalloc(sizeof(*rd), GFP_KERNEL); | |
6023 | if (!rd) | |
6024 | return NULL; | |
6025 | ||
68c38fc3 | 6026 | if (init_rootdomain(rd) != 0) { |
c6c4927b RR |
6027 | kfree(rd); |
6028 | return NULL; | |
6029 | } | |
57d885fe GH |
6030 | |
6031 | return rd; | |
6032 | } | |
6033 | ||
63b2ca30 | 6034 | static void free_sched_groups(struct sched_group *sg, int free_sgc) |
e3589f6c PZ |
6035 | { |
6036 | struct sched_group *tmp, *first; | |
6037 | ||
6038 | if (!sg) | |
6039 | return; | |
6040 | ||
6041 | first = sg; | |
6042 | do { | |
6043 | tmp = sg->next; | |
6044 | ||
63b2ca30 NP |
6045 | if (free_sgc && atomic_dec_and_test(&sg->sgc->ref)) |
6046 | kfree(sg->sgc); | |
e3589f6c PZ |
6047 | |
6048 | kfree(sg); | |
6049 | sg = tmp; | |
6050 | } while (sg != first); | |
6051 | } | |
6052 | ||
dce840a0 PZ |
6053 | static void free_sched_domain(struct rcu_head *rcu) |
6054 | { | |
6055 | struct sched_domain *sd = container_of(rcu, struct sched_domain, rcu); | |
e3589f6c PZ |
6056 | |
6057 | /* | |
6058 | * If its an overlapping domain it has private groups, iterate and | |
6059 | * nuke them all. | |
6060 | */ | |
6061 | if (sd->flags & SD_OVERLAP) { | |
6062 | free_sched_groups(sd->groups, 1); | |
6063 | } else if (atomic_dec_and_test(&sd->groups->ref)) { | |
63b2ca30 | 6064 | kfree(sd->groups->sgc); |
dce840a0 | 6065 | kfree(sd->groups); |
9c3f75cb | 6066 | } |
dce840a0 PZ |
6067 | kfree(sd); |
6068 | } | |
6069 | ||
6070 | static void destroy_sched_domain(struct sched_domain *sd, int cpu) | |
6071 | { | |
6072 | call_rcu(&sd->rcu, free_sched_domain); | |
6073 | } | |
6074 | ||
6075 | static void destroy_sched_domains(struct sched_domain *sd, int cpu) | |
6076 | { | |
6077 | for (; sd; sd = sd->parent) | |
6078 | destroy_sched_domain(sd, cpu); | |
6079 | } | |
6080 | ||
518cd623 PZ |
6081 | /* |
6082 | * Keep a special pointer to the highest sched_domain that has | |
6083 | * SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this | |
6084 | * allows us to avoid some pointer chasing select_idle_sibling(). | |
6085 | * | |
6086 | * Also keep a unique ID per domain (we use the first cpu number in | |
6087 | * the cpumask of the domain), this allows us to quickly tell if | |
39be3501 | 6088 | * two cpus are in the same cache domain, see cpus_share_cache(). |
518cd623 PZ |
6089 | */ |
6090 | DEFINE_PER_CPU(struct sched_domain *, sd_llc); | |
7d9ffa89 | 6091 | DEFINE_PER_CPU(int, sd_llc_size); |
518cd623 | 6092 | DEFINE_PER_CPU(int, sd_llc_id); |
fb13c7ee | 6093 | DEFINE_PER_CPU(struct sched_domain *, sd_numa); |
37dc6b50 PM |
6094 | DEFINE_PER_CPU(struct sched_domain *, sd_busy); |
6095 | DEFINE_PER_CPU(struct sched_domain *, sd_asym); | |
518cd623 PZ |
6096 | |
6097 | static void update_top_cache_domain(int cpu) | |
6098 | { | |
6099 | struct sched_domain *sd; | |
5d4cf996 | 6100 | struct sched_domain *busy_sd = NULL; |
518cd623 | 6101 | int id = cpu; |
7d9ffa89 | 6102 | int size = 1; |
518cd623 PZ |
6103 | |
6104 | sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES); | |
7d9ffa89 | 6105 | if (sd) { |
518cd623 | 6106 | id = cpumask_first(sched_domain_span(sd)); |
7d9ffa89 | 6107 | size = cpumask_weight(sched_domain_span(sd)); |
5d4cf996 | 6108 | busy_sd = sd->parent; /* sd_busy */ |
7d9ffa89 | 6109 | } |
5d4cf996 | 6110 | rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd); |
518cd623 PZ |
6111 | |
6112 | rcu_assign_pointer(per_cpu(sd_llc, cpu), sd); | |
7d9ffa89 | 6113 | per_cpu(sd_llc_size, cpu) = size; |
518cd623 | 6114 | per_cpu(sd_llc_id, cpu) = id; |
fb13c7ee MG |
6115 | |
6116 | sd = lowest_flag_domain(cpu, SD_NUMA); | |
6117 | rcu_assign_pointer(per_cpu(sd_numa, cpu), sd); | |
37dc6b50 PM |
6118 | |
6119 | sd = highest_flag_domain(cpu, SD_ASYM_PACKING); | |
6120 | rcu_assign_pointer(per_cpu(sd_asym, cpu), sd); | |
518cd623 PZ |
6121 | } |
6122 | ||
1da177e4 | 6123 | /* |
0eab9146 | 6124 | * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
1da177e4 LT |
6125 | * hold the hotplug lock. |
6126 | */ | |
0eab9146 IM |
6127 | static void |
6128 | cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) | |
1da177e4 | 6129 | { |
70b97a7f | 6130 | struct rq *rq = cpu_rq(cpu); |
245af2c7 SS |
6131 | struct sched_domain *tmp; |
6132 | ||
6133 | /* Remove the sched domains which do not contribute to scheduling. */ | |
f29c9b1c | 6134 | for (tmp = sd; tmp; ) { |
245af2c7 SS |
6135 | struct sched_domain *parent = tmp->parent; |
6136 | if (!parent) | |
6137 | break; | |
f29c9b1c | 6138 | |
1a848870 | 6139 | if (sd_parent_degenerate(tmp, parent)) { |
245af2c7 | 6140 | tmp->parent = parent->parent; |
1a848870 SS |
6141 | if (parent->parent) |
6142 | parent->parent->child = tmp; | |
10866e62 PZ |
6143 | /* |
6144 | * Transfer SD_PREFER_SIBLING down in case of a | |
6145 | * degenerate parent; the spans match for this | |
6146 | * so the property transfers. | |
6147 | */ | |
6148 | if (parent->flags & SD_PREFER_SIBLING) | |
6149 | tmp->flags |= SD_PREFER_SIBLING; | |
dce840a0 | 6150 | destroy_sched_domain(parent, cpu); |
f29c9b1c LZ |
6151 | } else |
6152 | tmp = tmp->parent; | |
245af2c7 SS |
6153 | } |
6154 | ||
1a848870 | 6155 | if (sd && sd_degenerate(sd)) { |
dce840a0 | 6156 | tmp = sd; |
245af2c7 | 6157 | sd = sd->parent; |
dce840a0 | 6158 | destroy_sched_domain(tmp, cpu); |
1a848870 SS |
6159 | if (sd) |
6160 | sd->child = NULL; | |
6161 | } | |
1da177e4 | 6162 | |
4cb98839 | 6163 | sched_domain_debug(sd, cpu); |
1da177e4 | 6164 | |
57d885fe | 6165 | rq_attach_root(rq, rd); |
dce840a0 | 6166 | tmp = rq->sd; |
674311d5 | 6167 | rcu_assign_pointer(rq->sd, sd); |
dce840a0 | 6168 | destroy_sched_domains(tmp, cpu); |
518cd623 PZ |
6169 | |
6170 | update_top_cache_domain(cpu); | |
1da177e4 LT |
6171 | } |
6172 | ||
1da177e4 LT |
6173 | /* Setup the mask of cpus configured for isolated domains */ |
6174 | static int __init isolated_cpu_setup(char *str) | |
6175 | { | |
a6e4491c PB |
6176 | int ret; |
6177 | ||
bdddd296 | 6178 | alloc_bootmem_cpumask_var(&cpu_isolated_map); |
a6e4491c PB |
6179 | ret = cpulist_parse(str, cpu_isolated_map); |
6180 | if (ret) { | |
6181 | pr_err("sched: Error, all isolcpus= values must be between 0 and %d\n", nr_cpu_ids); | |
6182 | return 0; | |
6183 | } | |
1da177e4 LT |
6184 | return 1; |
6185 | } | |
8927f494 | 6186 | __setup("isolcpus=", isolated_cpu_setup); |
1da177e4 | 6187 | |
49a02c51 | 6188 | struct s_data { |
21d42ccf | 6189 | struct sched_domain ** __percpu sd; |
49a02c51 AH |
6190 | struct root_domain *rd; |
6191 | }; | |
6192 | ||
2109b99e | 6193 | enum s_alloc { |
2109b99e | 6194 | sa_rootdomain, |
21d42ccf | 6195 | sa_sd, |
dce840a0 | 6196 | sa_sd_storage, |
2109b99e AH |
6197 | sa_none, |
6198 | }; | |
6199 | ||
c1174876 PZ |
6200 | /* |
6201 | * Build an iteration mask that can exclude certain CPUs from the upwards | |
6202 | * domain traversal. | |
6203 | * | |
6204 | * Asymmetric node setups can result in situations where the domain tree is of | |
6205 | * unequal depth, make sure to skip domains that already cover the entire | |
6206 | * range. | |
6207 | * | |
6208 | * In that case build_sched_domains() will have terminated the iteration early | |
6209 | * and our sibling sd spans will be empty. Domains should always include the | |
6210 | * cpu they're built on, so check that. | |
6211 | * | |
6212 | */ | |
6213 | static void build_group_mask(struct sched_domain *sd, struct sched_group *sg) | |
6214 | { | |
6215 | const struct cpumask *span = sched_domain_span(sd); | |
6216 | struct sd_data *sdd = sd->private; | |
6217 | struct sched_domain *sibling; | |
6218 | int i; | |
6219 | ||
6220 | for_each_cpu(i, span) { | |
6221 | sibling = *per_cpu_ptr(sdd->sd, i); | |
6222 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) | |
6223 | continue; | |
6224 | ||
6225 | cpumask_set_cpu(i, sched_group_mask(sg)); | |
6226 | } | |
6227 | } | |
6228 | ||
6229 | /* | |
6230 | * Return the canonical balance cpu for this group, this is the first cpu | |
6231 | * of this group that's also in the iteration mask. | |
6232 | */ | |
6233 | int group_balance_cpu(struct sched_group *sg) | |
6234 | { | |
6235 | return cpumask_first_and(sched_group_cpus(sg), sched_group_mask(sg)); | |
6236 | } | |
6237 | ||
e3589f6c PZ |
6238 | static int |
6239 | build_overlap_sched_groups(struct sched_domain *sd, int cpu) | |
6240 | { | |
6241 | struct sched_group *first = NULL, *last = NULL, *groups = NULL, *sg; | |
6242 | const struct cpumask *span = sched_domain_span(sd); | |
6243 | struct cpumask *covered = sched_domains_tmpmask; | |
6244 | struct sd_data *sdd = sd->private; | |
aaecac4a | 6245 | struct sched_domain *sibling; |
e3589f6c PZ |
6246 | int i; |
6247 | ||
6248 | cpumask_clear(covered); | |
6249 | ||
6250 | for_each_cpu(i, span) { | |
6251 | struct cpumask *sg_span; | |
6252 | ||
6253 | if (cpumask_test_cpu(i, covered)) | |
6254 | continue; | |
6255 | ||
aaecac4a | 6256 | sibling = *per_cpu_ptr(sdd->sd, i); |
c1174876 PZ |
6257 | |
6258 | /* See the comment near build_group_mask(). */ | |
aaecac4a | 6259 | if (!cpumask_test_cpu(i, sched_domain_span(sibling))) |
c1174876 PZ |
6260 | continue; |
6261 | ||
e3589f6c | 6262 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), |
4d78a223 | 6263 | GFP_KERNEL, cpu_to_node(cpu)); |
e3589f6c PZ |
6264 | |
6265 | if (!sg) | |
6266 | goto fail; | |
6267 | ||
6268 | sg_span = sched_group_cpus(sg); | |
aaecac4a ZZ |
6269 | if (sibling->child) |
6270 | cpumask_copy(sg_span, sched_domain_span(sibling->child)); | |
6271 | else | |
e3589f6c PZ |
6272 | cpumask_set_cpu(i, sg_span); |
6273 | ||
6274 | cpumask_or(covered, covered, sg_span); | |
6275 | ||
63b2ca30 NP |
6276 | sg->sgc = *per_cpu_ptr(sdd->sgc, i); |
6277 | if (atomic_inc_return(&sg->sgc->ref) == 1) | |
c1174876 PZ |
6278 | build_group_mask(sd, sg); |
6279 | ||
c3decf0d | 6280 | /* |
63b2ca30 | 6281 | * Initialize sgc->capacity such that even if we mess up the |
c3decf0d PZ |
6282 | * domains and no possible iteration will get us here, we won't |
6283 | * die on a /0 trap. | |
6284 | */ | |
ca8ce3d0 | 6285 | sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sg_span); |
e3589f6c | 6286 | |
c1174876 PZ |
6287 | /* |
6288 | * Make sure the first group of this domain contains the | |
6289 | * canonical balance cpu. Otherwise the sched_domain iteration | |
6290 | * breaks. See update_sg_lb_stats(). | |
6291 | */ | |
74a5ce20 | 6292 | if ((!groups && cpumask_test_cpu(cpu, sg_span)) || |
c1174876 | 6293 | group_balance_cpu(sg) == cpu) |
e3589f6c PZ |
6294 | groups = sg; |
6295 | ||
6296 | if (!first) | |
6297 | first = sg; | |
6298 | if (last) | |
6299 | last->next = sg; | |
6300 | last = sg; | |
6301 | last->next = first; | |
6302 | } | |
6303 | sd->groups = groups; | |
6304 | ||
6305 | return 0; | |
6306 | ||
6307 | fail: | |
6308 | free_sched_groups(first, 0); | |
6309 | ||
6310 | return -ENOMEM; | |
6311 | } | |
6312 | ||
dce840a0 | 6313 | static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg) |
1da177e4 | 6314 | { |
dce840a0 PZ |
6315 | struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu); |
6316 | struct sched_domain *child = sd->child; | |
1da177e4 | 6317 | |
dce840a0 PZ |
6318 | if (child) |
6319 | cpu = cpumask_first(sched_domain_span(child)); | |
1e9f28fa | 6320 | |
9c3f75cb | 6321 | if (sg) { |
dce840a0 | 6322 | *sg = *per_cpu_ptr(sdd->sg, cpu); |
63b2ca30 NP |
6323 | (*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu); |
6324 | atomic_set(&(*sg)->sgc->ref, 1); /* for claim_allocations */ | |
9c3f75cb | 6325 | } |
dce840a0 PZ |
6326 | |
6327 | return cpu; | |
1e9f28fa | 6328 | } |
1e9f28fa | 6329 | |
01a08546 | 6330 | /* |
dce840a0 PZ |
6331 | * build_sched_groups will build a circular linked list of the groups |
6332 | * covered by the given span, and will set each group's ->cpumask correctly, | |
ced549fa | 6333 | * and ->cpu_capacity to 0. |
e3589f6c PZ |
6334 | * |
6335 | * Assumes the sched_domain tree is fully constructed | |
01a08546 | 6336 | */ |
e3589f6c PZ |
6337 | static int |
6338 | build_sched_groups(struct sched_domain *sd, int cpu) | |
1da177e4 | 6339 | { |
dce840a0 PZ |
6340 | struct sched_group *first = NULL, *last = NULL; |
6341 | struct sd_data *sdd = sd->private; | |
6342 | const struct cpumask *span = sched_domain_span(sd); | |
f96225fd | 6343 | struct cpumask *covered; |
dce840a0 | 6344 | int i; |
9c1cfda2 | 6345 | |
e3589f6c PZ |
6346 | get_group(cpu, sdd, &sd->groups); |
6347 | atomic_inc(&sd->groups->ref); | |
6348 | ||
0936629f | 6349 | if (cpu != cpumask_first(span)) |
e3589f6c PZ |
6350 | return 0; |
6351 | ||
f96225fd PZ |
6352 | lockdep_assert_held(&sched_domains_mutex); |
6353 | covered = sched_domains_tmpmask; | |
6354 | ||
dce840a0 | 6355 | cpumask_clear(covered); |
6711cab4 | 6356 | |
dce840a0 PZ |
6357 | for_each_cpu(i, span) { |
6358 | struct sched_group *sg; | |
cd08e923 | 6359 | int group, j; |
6711cab4 | 6360 | |
dce840a0 PZ |
6361 | if (cpumask_test_cpu(i, covered)) |
6362 | continue; | |
6711cab4 | 6363 | |
cd08e923 | 6364 | group = get_group(i, sdd, &sg); |
c1174876 | 6365 | cpumask_setall(sched_group_mask(sg)); |
0601a88d | 6366 | |
dce840a0 PZ |
6367 | for_each_cpu(j, span) { |
6368 | if (get_group(j, sdd, NULL) != group) | |
6369 | continue; | |
0601a88d | 6370 | |
dce840a0 PZ |
6371 | cpumask_set_cpu(j, covered); |
6372 | cpumask_set_cpu(j, sched_group_cpus(sg)); | |
6373 | } | |
0601a88d | 6374 | |
dce840a0 PZ |
6375 | if (!first) |
6376 | first = sg; | |
6377 | if (last) | |
6378 | last->next = sg; | |
6379 | last = sg; | |
6380 | } | |
6381 | last->next = first; | |
e3589f6c PZ |
6382 | |
6383 | return 0; | |
0601a88d | 6384 | } |
51888ca2 | 6385 | |
89c4710e | 6386 | /* |
63b2ca30 | 6387 | * Initialize sched groups cpu_capacity. |
89c4710e | 6388 | * |
63b2ca30 | 6389 | * cpu_capacity indicates the capacity of sched group, which is used while |
89c4710e | 6390 | * distributing the load between different sched groups in a sched domain. |
63b2ca30 NP |
6391 | * Typically cpu_capacity for all the groups in a sched domain will be same |
6392 | * unless there are asymmetries in the topology. If there are asymmetries, | |
6393 | * group having more cpu_capacity will pickup more load compared to the | |
6394 | * group having less cpu_capacity. | |
89c4710e | 6395 | */ |
63b2ca30 | 6396 | static void init_sched_groups_capacity(int cpu, struct sched_domain *sd) |
89c4710e | 6397 | { |
e3589f6c | 6398 | struct sched_group *sg = sd->groups; |
89c4710e | 6399 | |
94c95ba6 | 6400 | WARN_ON(!sg); |
e3589f6c PZ |
6401 | |
6402 | do { | |
6403 | sg->group_weight = cpumask_weight(sched_group_cpus(sg)); | |
6404 | sg = sg->next; | |
6405 | } while (sg != sd->groups); | |
89c4710e | 6406 | |
c1174876 | 6407 | if (cpu != group_balance_cpu(sg)) |
e3589f6c | 6408 | return; |
aae6d3dd | 6409 | |
63b2ca30 NP |
6410 | update_group_capacity(sd, cpu); |
6411 | atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight); | |
89c4710e SS |
6412 | } |
6413 | ||
7c16ec58 MT |
6414 | /* |
6415 | * Initializers for schedule domains | |
6416 | * Non-inlined to reduce accumulated stack pressure in build_sched_domains() | |
6417 | */ | |
6418 | ||
1d3504fc | 6419 | static int default_relax_domain_level = -1; |
60495e77 | 6420 | int sched_domain_level_max; |
1d3504fc HS |
6421 | |
6422 | static int __init setup_relax_domain_level(char *str) | |
6423 | { | |
a841f8ce DS |
6424 | if (kstrtoint(str, 0, &default_relax_domain_level)) |
6425 | pr_warn("Unable to set relax_domain_level\n"); | |
30e0e178 | 6426 | |
1d3504fc HS |
6427 | return 1; |
6428 | } | |
6429 | __setup("relax_domain_level=", setup_relax_domain_level); | |
6430 | ||
6431 | static void set_domain_attribute(struct sched_domain *sd, | |
6432 | struct sched_domain_attr *attr) | |
6433 | { | |
6434 | int request; | |
6435 | ||
6436 | if (!attr || attr->relax_domain_level < 0) { | |
6437 | if (default_relax_domain_level < 0) | |
6438 | return; | |
6439 | else | |
6440 | request = default_relax_domain_level; | |
6441 | } else | |
6442 | request = attr->relax_domain_level; | |
6443 | if (request < sd->level) { | |
6444 | /* turn off idle balance on this domain */ | |
c88d5910 | 6445 | sd->flags &= ~(SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
6446 | } else { |
6447 | /* turn on idle balance on this domain */ | |
c88d5910 | 6448 | sd->flags |= (SD_BALANCE_WAKE|SD_BALANCE_NEWIDLE); |
1d3504fc HS |
6449 | } |
6450 | } | |
6451 | ||
54ab4ff4 PZ |
6452 | static void __sdt_free(const struct cpumask *cpu_map); |
6453 | static int __sdt_alloc(const struct cpumask *cpu_map); | |
6454 | ||
2109b99e AH |
6455 | static void __free_domain_allocs(struct s_data *d, enum s_alloc what, |
6456 | const struct cpumask *cpu_map) | |
6457 | { | |
6458 | switch (what) { | |
2109b99e | 6459 | case sa_rootdomain: |
822ff793 PZ |
6460 | if (!atomic_read(&d->rd->refcount)) |
6461 | free_rootdomain(&d->rd->rcu); /* fall through */ | |
21d42ccf PZ |
6462 | case sa_sd: |
6463 | free_percpu(d->sd); /* fall through */ | |
dce840a0 | 6464 | case sa_sd_storage: |
54ab4ff4 | 6465 | __sdt_free(cpu_map); /* fall through */ |
2109b99e AH |
6466 | case sa_none: |
6467 | break; | |
6468 | } | |
6469 | } | |
3404c8d9 | 6470 | |
2109b99e AH |
6471 | static enum s_alloc __visit_domain_allocation_hell(struct s_data *d, |
6472 | const struct cpumask *cpu_map) | |
6473 | { | |
dce840a0 PZ |
6474 | memset(d, 0, sizeof(*d)); |
6475 | ||
54ab4ff4 PZ |
6476 | if (__sdt_alloc(cpu_map)) |
6477 | return sa_sd_storage; | |
dce840a0 PZ |
6478 | d->sd = alloc_percpu(struct sched_domain *); |
6479 | if (!d->sd) | |
6480 | return sa_sd_storage; | |
2109b99e | 6481 | d->rd = alloc_rootdomain(); |
dce840a0 | 6482 | if (!d->rd) |
21d42ccf | 6483 | return sa_sd; |
2109b99e AH |
6484 | return sa_rootdomain; |
6485 | } | |
57d885fe | 6486 | |
dce840a0 PZ |
6487 | /* |
6488 | * NULL the sd_data elements we've used to build the sched_domain and | |
6489 | * sched_group structure so that the subsequent __free_domain_allocs() | |
6490 | * will not free the data we're using. | |
6491 | */ | |
6492 | static void claim_allocations(int cpu, struct sched_domain *sd) | |
6493 | { | |
6494 | struct sd_data *sdd = sd->private; | |
dce840a0 PZ |
6495 | |
6496 | WARN_ON_ONCE(*per_cpu_ptr(sdd->sd, cpu) != sd); | |
6497 | *per_cpu_ptr(sdd->sd, cpu) = NULL; | |
6498 | ||
e3589f6c | 6499 | if (atomic_read(&(*per_cpu_ptr(sdd->sg, cpu))->ref)) |
dce840a0 | 6500 | *per_cpu_ptr(sdd->sg, cpu) = NULL; |
e3589f6c | 6501 | |
63b2ca30 NP |
6502 | if (atomic_read(&(*per_cpu_ptr(sdd->sgc, cpu))->ref)) |
6503 | *per_cpu_ptr(sdd->sgc, cpu) = NULL; | |
dce840a0 PZ |
6504 | } |
6505 | ||
cb83b629 | 6506 | #ifdef CONFIG_NUMA |
cb83b629 | 6507 | static int sched_domains_numa_levels; |
e3fe70b1 | 6508 | enum numa_topology_type sched_numa_topology_type; |
cb83b629 | 6509 | static int *sched_domains_numa_distance; |
9942f79b | 6510 | int sched_max_numa_distance; |
cb83b629 PZ |
6511 | static struct cpumask ***sched_domains_numa_masks; |
6512 | static int sched_domains_curr_level; | |
143e1e28 | 6513 | #endif |
cb83b629 | 6514 | |
143e1e28 VG |
6515 | /* |
6516 | * SD_flags allowed in topology descriptions. | |
6517 | * | |
5d4dfddd | 6518 | * SD_SHARE_CPUCAPACITY - describes SMT topologies |
143e1e28 VG |
6519 | * SD_SHARE_PKG_RESOURCES - describes shared caches |
6520 | * SD_NUMA - describes NUMA topologies | |
d77b3ed5 | 6521 | * SD_SHARE_POWERDOMAIN - describes shared power domain |
143e1e28 VG |
6522 | * |
6523 | * Odd one out: | |
6524 | * SD_ASYM_PACKING - describes SMT quirks | |
6525 | */ | |
6526 | #define TOPOLOGY_SD_FLAGS \ | |
5d4dfddd | 6527 | (SD_SHARE_CPUCAPACITY | \ |
143e1e28 VG |
6528 | SD_SHARE_PKG_RESOURCES | \ |
6529 | SD_NUMA | \ | |
d77b3ed5 VG |
6530 | SD_ASYM_PACKING | \ |
6531 | SD_SHARE_POWERDOMAIN) | |
cb83b629 PZ |
6532 | |
6533 | static struct sched_domain * | |
143e1e28 | 6534 | sd_init(struct sched_domain_topology_level *tl, int cpu) |
cb83b629 PZ |
6535 | { |
6536 | struct sched_domain *sd = *per_cpu_ptr(tl->data.sd, cpu); | |
143e1e28 VG |
6537 | int sd_weight, sd_flags = 0; |
6538 | ||
6539 | #ifdef CONFIG_NUMA | |
6540 | /* | |
6541 | * Ugly hack to pass state to sd_numa_mask()... | |
6542 | */ | |
6543 | sched_domains_curr_level = tl->numa_level; | |
6544 | #endif | |
6545 | ||
6546 | sd_weight = cpumask_weight(tl->mask(cpu)); | |
6547 | ||
6548 | if (tl->sd_flags) | |
6549 | sd_flags = (*tl->sd_flags)(); | |
6550 | if (WARN_ONCE(sd_flags & ~TOPOLOGY_SD_FLAGS, | |
6551 | "wrong sd_flags in topology description\n")) | |
6552 | sd_flags &= ~TOPOLOGY_SD_FLAGS; | |
cb83b629 PZ |
6553 | |
6554 | *sd = (struct sched_domain){ | |
6555 | .min_interval = sd_weight, | |
6556 | .max_interval = 2*sd_weight, | |
6557 | .busy_factor = 32, | |
870a0bb5 | 6558 | .imbalance_pct = 125, |
143e1e28 VG |
6559 | |
6560 | .cache_nice_tries = 0, | |
6561 | .busy_idx = 0, | |
6562 | .idle_idx = 0, | |
cb83b629 PZ |
6563 | .newidle_idx = 0, |
6564 | .wake_idx = 0, | |
6565 | .forkexec_idx = 0, | |
6566 | ||
6567 | .flags = 1*SD_LOAD_BALANCE | |
6568 | | 1*SD_BALANCE_NEWIDLE | |
143e1e28 VG |
6569 | | 1*SD_BALANCE_EXEC |
6570 | | 1*SD_BALANCE_FORK | |
cb83b629 | 6571 | | 0*SD_BALANCE_WAKE |
143e1e28 | 6572 | | 1*SD_WAKE_AFFINE |
5d4dfddd | 6573 | | 0*SD_SHARE_CPUCAPACITY |
cb83b629 | 6574 | | 0*SD_SHARE_PKG_RESOURCES |
143e1e28 | 6575 | | 0*SD_SERIALIZE |
cb83b629 | 6576 | | 0*SD_PREFER_SIBLING |
143e1e28 VG |
6577 | | 0*SD_NUMA |
6578 | | sd_flags | |
cb83b629 | 6579 | , |
143e1e28 | 6580 | |
cb83b629 PZ |
6581 | .last_balance = jiffies, |
6582 | .balance_interval = sd_weight, | |
143e1e28 | 6583 | .smt_gain = 0, |
2b4cfe64 JL |
6584 | .max_newidle_lb_cost = 0, |
6585 | .next_decay_max_lb_cost = jiffies, | |
143e1e28 VG |
6586 | #ifdef CONFIG_SCHED_DEBUG |
6587 | .name = tl->name, | |
6588 | #endif | |
cb83b629 | 6589 | }; |
cb83b629 PZ |
6590 | |
6591 | /* | |
143e1e28 | 6592 | * Convert topological properties into behaviour. |
cb83b629 | 6593 | */ |
143e1e28 | 6594 | |
5d4dfddd | 6595 | if (sd->flags & SD_SHARE_CPUCAPACITY) { |
caff37ef | 6596 | sd->flags |= SD_PREFER_SIBLING; |
143e1e28 VG |
6597 | sd->imbalance_pct = 110; |
6598 | sd->smt_gain = 1178; /* ~15% */ | |
143e1e28 VG |
6599 | |
6600 | } else if (sd->flags & SD_SHARE_PKG_RESOURCES) { | |
6601 | sd->imbalance_pct = 117; | |
6602 | sd->cache_nice_tries = 1; | |
6603 | sd->busy_idx = 2; | |
6604 | ||
6605 | #ifdef CONFIG_NUMA | |
6606 | } else if (sd->flags & SD_NUMA) { | |
6607 | sd->cache_nice_tries = 2; | |
6608 | sd->busy_idx = 3; | |
6609 | sd->idle_idx = 2; | |
6610 | ||
6611 | sd->flags |= SD_SERIALIZE; | |
6612 | if (sched_domains_numa_distance[tl->numa_level] > RECLAIM_DISTANCE) { | |
6613 | sd->flags &= ~(SD_BALANCE_EXEC | | |
6614 | SD_BALANCE_FORK | | |
6615 | SD_WAKE_AFFINE); | |
6616 | } | |
6617 | ||
6618 | #endif | |
6619 | } else { | |
6620 | sd->flags |= SD_PREFER_SIBLING; | |
6621 | sd->cache_nice_tries = 1; | |
6622 | sd->busy_idx = 2; | |
6623 | sd->idle_idx = 1; | |
6624 | } | |
6625 | ||
6626 | sd->private = &tl->data; | |
cb83b629 PZ |
6627 | |
6628 | return sd; | |
6629 | } | |
6630 | ||
143e1e28 VG |
6631 | /* |
6632 | * Topology list, bottom-up. | |
6633 | */ | |
6634 | static struct sched_domain_topology_level default_topology[] = { | |
6635 | #ifdef CONFIG_SCHED_SMT | |
6636 | { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) }, | |
6637 | #endif | |
6638 | #ifdef CONFIG_SCHED_MC | |
6639 | { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) }, | |
143e1e28 VG |
6640 | #endif |
6641 | { cpu_cpu_mask, SD_INIT_NAME(DIE) }, | |
6642 | { NULL, }, | |
6643 | }; | |
6644 | ||
c6e1e7b5 JG |
6645 | static struct sched_domain_topology_level *sched_domain_topology = |
6646 | default_topology; | |
143e1e28 VG |
6647 | |
6648 | #define for_each_sd_topology(tl) \ | |
6649 | for (tl = sched_domain_topology; tl->mask; tl++) | |
6650 | ||
6651 | void set_sched_topology(struct sched_domain_topology_level *tl) | |
6652 | { | |
6653 | sched_domain_topology = tl; | |
6654 | } | |
6655 | ||
6656 | #ifdef CONFIG_NUMA | |
6657 | ||
cb83b629 PZ |
6658 | static const struct cpumask *sd_numa_mask(int cpu) |
6659 | { | |
6660 | return sched_domains_numa_masks[sched_domains_curr_level][cpu_to_node(cpu)]; | |
6661 | } | |
6662 | ||
d039ac60 PZ |
6663 | static void sched_numa_warn(const char *str) |
6664 | { | |
6665 | static int done = false; | |
6666 | int i,j; | |
6667 | ||
6668 | if (done) | |
6669 | return; | |
6670 | ||
6671 | done = true; | |
6672 | ||
6673 | printk(KERN_WARNING "ERROR: %s\n\n", str); | |
6674 | ||
6675 | for (i = 0; i < nr_node_ids; i++) { | |
6676 | printk(KERN_WARNING " "); | |
6677 | for (j = 0; j < nr_node_ids; j++) | |
6678 | printk(KERN_CONT "%02d ", node_distance(i,j)); | |
6679 | printk(KERN_CONT "\n"); | |
6680 | } | |
6681 | printk(KERN_WARNING "\n"); | |
6682 | } | |
6683 | ||
9942f79b | 6684 | bool find_numa_distance(int distance) |
d039ac60 PZ |
6685 | { |
6686 | int i; | |
6687 | ||
6688 | if (distance == node_distance(0, 0)) | |
6689 | return true; | |
6690 | ||
6691 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
6692 | if (sched_domains_numa_distance[i] == distance) | |
6693 | return true; | |
6694 | } | |
6695 | ||
6696 | return false; | |
6697 | } | |
6698 | ||
e3fe70b1 RR |
6699 | /* |
6700 | * A system can have three types of NUMA topology: | |
6701 | * NUMA_DIRECT: all nodes are directly connected, or not a NUMA system | |
6702 | * NUMA_GLUELESS_MESH: some nodes reachable through intermediary nodes | |
6703 | * NUMA_BACKPLANE: nodes can reach other nodes through a backplane | |
6704 | * | |
6705 | * The difference between a glueless mesh topology and a backplane | |
6706 | * topology lies in whether communication between not directly | |
6707 | * connected nodes goes through intermediary nodes (where programs | |
6708 | * could run), or through backplane controllers. This affects | |
6709 | * placement of programs. | |
6710 | * | |
6711 | * The type of topology can be discerned with the following tests: | |
6712 | * - If the maximum distance between any nodes is 1 hop, the system | |
6713 | * is directly connected. | |
6714 | * - If for two nodes A and B, located N > 1 hops away from each other, | |
6715 | * there is an intermediary node C, which is < N hops away from both | |
6716 | * nodes A and B, the system is a glueless mesh. | |
6717 | */ | |
6718 | static void init_numa_topology_type(void) | |
6719 | { | |
6720 | int a, b, c, n; | |
6721 | ||
6722 | n = sched_max_numa_distance; | |
6723 | ||
e237882b | 6724 | if (sched_domains_numa_levels <= 1) { |
e3fe70b1 | 6725 | sched_numa_topology_type = NUMA_DIRECT; |
e237882b AG |
6726 | return; |
6727 | } | |
e3fe70b1 RR |
6728 | |
6729 | for_each_online_node(a) { | |
6730 | for_each_online_node(b) { | |
6731 | /* Find two nodes furthest removed from each other. */ | |
6732 | if (node_distance(a, b) < n) | |
6733 | continue; | |
6734 | ||
6735 | /* Is there an intermediary node between a and b? */ | |
6736 | for_each_online_node(c) { | |
6737 | if (node_distance(a, c) < n && | |
6738 | node_distance(b, c) < n) { | |
6739 | sched_numa_topology_type = | |
6740 | NUMA_GLUELESS_MESH; | |
6741 | return; | |
6742 | } | |
6743 | } | |
6744 | ||
6745 | sched_numa_topology_type = NUMA_BACKPLANE; | |
6746 | return; | |
6747 | } | |
6748 | } | |
6749 | } | |
6750 | ||
cb83b629 PZ |
6751 | static void sched_init_numa(void) |
6752 | { | |
6753 | int next_distance, curr_distance = node_distance(0, 0); | |
6754 | struct sched_domain_topology_level *tl; | |
6755 | int level = 0; | |
6756 | int i, j, k; | |
6757 | ||
cb83b629 PZ |
6758 | sched_domains_numa_distance = kzalloc(sizeof(int) * nr_node_ids, GFP_KERNEL); |
6759 | if (!sched_domains_numa_distance) | |
6760 | return; | |
6761 | ||
6762 | /* | |
6763 | * O(nr_nodes^2) deduplicating selection sort -- in order to find the | |
6764 | * unique distances in the node_distance() table. | |
6765 | * | |
6766 | * Assumes node_distance(0,j) includes all distances in | |
6767 | * node_distance(i,j) in order to avoid cubic time. | |
cb83b629 PZ |
6768 | */ |
6769 | next_distance = curr_distance; | |
6770 | for (i = 0; i < nr_node_ids; i++) { | |
6771 | for (j = 0; j < nr_node_ids; j++) { | |
d039ac60 PZ |
6772 | for (k = 0; k < nr_node_ids; k++) { |
6773 | int distance = node_distance(i, k); | |
6774 | ||
6775 | if (distance > curr_distance && | |
6776 | (distance < next_distance || | |
6777 | next_distance == curr_distance)) | |
6778 | next_distance = distance; | |
6779 | ||
6780 | /* | |
6781 | * While not a strong assumption it would be nice to know | |
6782 | * about cases where if node A is connected to B, B is not | |
6783 | * equally connected to A. | |
6784 | */ | |
6785 | if (sched_debug() && node_distance(k, i) != distance) | |
6786 | sched_numa_warn("Node-distance not symmetric"); | |
6787 | ||
6788 | if (sched_debug() && i && !find_numa_distance(distance)) | |
6789 | sched_numa_warn("Node-0 not representative"); | |
6790 | } | |
6791 | if (next_distance != curr_distance) { | |
6792 | sched_domains_numa_distance[level++] = next_distance; | |
6793 | sched_domains_numa_levels = level; | |
6794 | curr_distance = next_distance; | |
6795 | } else break; | |
cb83b629 | 6796 | } |
d039ac60 PZ |
6797 | |
6798 | /* | |
6799 | * In case of sched_debug() we verify the above assumption. | |
6800 | */ | |
6801 | if (!sched_debug()) | |
6802 | break; | |
cb83b629 | 6803 | } |
c123588b AR |
6804 | |
6805 | if (!level) | |
6806 | return; | |
6807 | ||
cb83b629 PZ |
6808 | /* |
6809 | * 'level' contains the number of unique distances, excluding the | |
6810 | * identity distance node_distance(i,i). | |
6811 | * | |
28b4a521 | 6812 | * The sched_domains_numa_distance[] array includes the actual distance |
cb83b629 PZ |
6813 | * numbers. |
6814 | */ | |
6815 | ||
5f7865f3 TC |
6816 | /* |
6817 | * Here, we should temporarily reset sched_domains_numa_levels to 0. | |
6818 | * If it fails to allocate memory for array sched_domains_numa_masks[][], | |
6819 | * the array will contain less then 'level' members. This could be | |
6820 | * dangerous when we use it to iterate array sched_domains_numa_masks[][] | |
6821 | * in other functions. | |
6822 | * | |
6823 | * We reset it to 'level' at the end of this function. | |
6824 | */ | |
6825 | sched_domains_numa_levels = 0; | |
6826 | ||
cb83b629 PZ |
6827 | sched_domains_numa_masks = kzalloc(sizeof(void *) * level, GFP_KERNEL); |
6828 | if (!sched_domains_numa_masks) | |
6829 | return; | |
6830 | ||
6831 | /* | |
6832 | * Now for each level, construct a mask per node which contains all | |
6833 | * cpus of nodes that are that many hops away from us. | |
6834 | */ | |
6835 | for (i = 0; i < level; i++) { | |
6836 | sched_domains_numa_masks[i] = | |
6837 | kzalloc(nr_node_ids * sizeof(void *), GFP_KERNEL); | |
6838 | if (!sched_domains_numa_masks[i]) | |
6839 | return; | |
6840 | ||
6841 | for (j = 0; j < nr_node_ids; j++) { | |
2ea45800 | 6842 | struct cpumask *mask = kzalloc(cpumask_size(), GFP_KERNEL); |
cb83b629 PZ |
6843 | if (!mask) |
6844 | return; | |
6845 | ||
6846 | sched_domains_numa_masks[i][j] = mask; | |
6847 | ||
9c03ee14 | 6848 | for_each_node(k) { |
dd7d8634 | 6849 | if (node_distance(j, k) > sched_domains_numa_distance[i]) |
cb83b629 PZ |
6850 | continue; |
6851 | ||
6852 | cpumask_or(mask, mask, cpumask_of_node(k)); | |
6853 | } | |
6854 | } | |
6855 | } | |
6856 | ||
143e1e28 VG |
6857 | /* Compute default topology size */ |
6858 | for (i = 0; sched_domain_topology[i].mask; i++); | |
6859 | ||
c515db8c | 6860 | tl = kzalloc((i + level + 1) * |
cb83b629 PZ |
6861 | sizeof(struct sched_domain_topology_level), GFP_KERNEL); |
6862 | if (!tl) | |
6863 | return; | |
6864 | ||
6865 | /* | |
6866 | * Copy the default topology bits.. | |
6867 | */ | |
143e1e28 VG |
6868 | for (i = 0; sched_domain_topology[i].mask; i++) |
6869 | tl[i] = sched_domain_topology[i]; | |
cb83b629 PZ |
6870 | |
6871 | /* | |
6872 | * .. and append 'j' levels of NUMA goodness. | |
6873 | */ | |
6874 | for (j = 0; j < level; i++, j++) { | |
6875 | tl[i] = (struct sched_domain_topology_level){ | |
cb83b629 | 6876 | .mask = sd_numa_mask, |
143e1e28 | 6877 | .sd_flags = cpu_numa_flags, |
cb83b629 PZ |
6878 | .flags = SDTL_OVERLAP, |
6879 | .numa_level = j, | |
143e1e28 | 6880 | SD_INIT_NAME(NUMA) |
cb83b629 PZ |
6881 | }; |
6882 | } | |
6883 | ||
6884 | sched_domain_topology = tl; | |
5f7865f3 TC |
6885 | |
6886 | sched_domains_numa_levels = level; | |
9942f79b | 6887 | sched_max_numa_distance = sched_domains_numa_distance[level - 1]; |
e3fe70b1 RR |
6888 | |
6889 | init_numa_topology_type(); | |
cb83b629 | 6890 | } |
301a5cba TC |
6891 | |
6892 | static void sched_domains_numa_masks_set(int cpu) | |
6893 | { | |
6894 | int i, j; | |
6895 | int node = cpu_to_node(cpu); | |
6896 | ||
6897 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
6898 | for (j = 0; j < nr_node_ids; j++) { | |
6899 | if (node_distance(j, node) <= sched_domains_numa_distance[i]) | |
6900 | cpumask_set_cpu(cpu, sched_domains_numa_masks[i][j]); | |
6901 | } | |
6902 | } | |
6903 | } | |
6904 | ||
6905 | static void sched_domains_numa_masks_clear(int cpu) | |
6906 | { | |
6907 | int i, j; | |
6908 | for (i = 0; i < sched_domains_numa_levels; i++) { | |
6909 | for (j = 0; j < nr_node_ids; j++) | |
6910 | cpumask_clear_cpu(cpu, sched_domains_numa_masks[i][j]); | |
6911 | } | |
6912 | } | |
6913 | ||
6914 | /* | |
6915 | * Update sched_domains_numa_masks[level][node] array when new cpus | |
6916 | * are onlined. | |
6917 | */ | |
6918 | static int sched_domains_numa_masks_update(struct notifier_block *nfb, | |
6919 | unsigned long action, | |
6920 | void *hcpu) | |
6921 | { | |
6922 | int cpu = (long)hcpu; | |
6923 | ||
6924 | switch (action & ~CPU_TASKS_FROZEN) { | |
6925 | case CPU_ONLINE: | |
6926 | sched_domains_numa_masks_set(cpu); | |
6927 | break; | |
6928 | ||
6929 | case CPU_DEAD: | |
6930 | sched_domains_numa_masks_clear(cpu); | |
6931 | break; | |
6932 | ||
6933 | default: | |
6934 | return NOTIFY_DONE; | |
6935 | } | |
6936 | ||
6937 | return NOTIFY_OK; | |
cb83b629 PZ |
6938 | } |
6939 | #else | |
6940 | static inline void sched_init_numa(void) | |
6941 | { | |
6942 | } | |
301a5cba TC |
6943 | |
6944 | static int sched_domains_numa_masks_update(struct notifier_block *nfb, | |
6945 | unsigned long action, | |
6946 | void *hcpu) | |
6947 | { | |
6948 | return 0; | |
6949 | } | |
cb83b629 PZ |
6950 | #endif /* CONFIG_NUMA */ |
6951 | ||
54ab4ff4 PZ |
6952 | static int __sdt_alloc(const struct cpumask *cpu_map) |
6953 | { | |
6954 | struct sched_domain_topology_level *tl; | |
6955 | int j; | |
6956 | ||
27723a68 | 6957 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
6958 | struct sd_data *sdd = &tl->data; |
6959 | ||
6960 | sdd->sd = alloc_percpu(struct sched_domain *); | |
6961 | if (!sdd->sd) | |
6962 | return -ENOMEM; | |
6963 | ||
6964 | sdd->sg = alloc_percpu(struct sched_group *); | |
6965 | if (!sdd->sg) | |
6966 | return -ENOMEM; | |
6967 | ||
63b2ca30 NP |
6968 | sdd->sgc = alloc_percpu(struct sched_group_capacity *); |
6969 | if (!sdd->sgc) | |
9c3f75cb PZ |
6970 | return -ENOMEM; |
6971 | ||
54ab4ff4 PZ |
6972 | for_each_cpu(j, cpu_map) { |
6973 | struct sched_domain *sd; | |
6974 | struct sched_group *sg; | |
63b2ca30 | 6975 | struct sched_group_capacity *sgc; |
54ab4ff4 | 6976 | |
5cc389bc | 6977 | sd = kzalloc_node(sizeof(struct sched_domain) + cpumask_size(), |
54ab4ff4 PZ |
6978 | GFP_KERNEL, cpu_to_node(j)); |
6979 | if (!sd) | |
6980 | return -ENOMEM; | |
6981 | ||
6982 | *per_cpu_ptr(sdd->sd, j) = sd; | |
6983 | ||
6984 | sg = kzalloc_node(sizeof(struct sched_group) + cpumask_size(), | |
6985 | GFP_KERNEL, cpu_to_node(j)); | |
6986 | if (!sg) | |
6987 | return -ENOMEM; | |
6988 | ||
30b4e9eb IM |
6989 | sg->next = sg; |
6990 | ||
54ab4ff4 | 6991 | *per_cpu_ptr(sdd->sg, j) = sg; |
9c3f75cb | 6992 | |
63b2ca30 | 6993 | sgc = kzalloc_node(sizeof(struct sched_group_capacity) + cpumask_size(), |
9c3f75cb | 6994 | GFP_KERNEL, cpu_to_node(j)); |
63b2ca30 | 6995 | if (!sgc) |
9c3f75cb PZ |
6996 | return -ENOMEM; |
6997 | ||
63b2ca30 | 6998 | *per_cpu_ptr(sdd->sgc, j) = sgc; |
54ab4ff4 PZ |
6999 | } |
7000 | } | |
7001 | ||
7002 | return 0; | |
7003 | } | |
7004 | ||
7005 | static void __sdt_free(const struct cpumask *cpu_map) | |
7006 | { | |
7007 | struct sched_domain_topology_level *tl; | |
7008 | int j; | |
7009 | ||
27723a68 | 7010 | for_each_sd_topology(tl) { |
54ab4ff4 PZ |
7011 | struct sd_data *sdd = &tl->data; |
7012 | ||
7013 | for_each_cpu(j, cpu_map) { | |
fb2cf2c6 | 7014 | struct sched_domain *sd; |
7015 | ||
7016 | if (sdd->sd) { | |
7017 | sd = *per_cpu_ptr(sdd->sd, j); | |
7018 | if (sd && (sd->flags & SD_OVERLAP)) | |
7019 | free_sched_groups(sd->groups, 0); | |
7020 | kfree(*per_cpu_ptr(sdd->sd, j)); | |
7021 | } | |
7022 | ||
7023 | if (sdd->sg) | |
7024 | kfree(*per_cpu_ptr(sdd->sg, j)); | |
63b2ca30 NP |
7025 | if (sdd->sgc) |
7026 | kfree(*per_cpu_ptr(sdd->sgc, j)); | |
54ab4ff4 PZ |
7027 | } |
7028 | free_percpu(sdd->sd); | |
fb2cf2c6 | 7029 | sdd->sd = NULL; |
54ab4ff4 | 7030 | free_percpu(sdd->sg); |
fb2cf2c6 | 7031 | sdd->sg = NULL; |
63b2ca30 NP |
7032 | free_percpu(sdd->sgc); |
7033 | sdd->sgc = NULL; | |
54ab4ff4 PZ |
7034 | } |
7035 | } | |
7036 | ||
2c402dc3 | 7037 | struct sched_domain *build_sched_domain(struct sched_domain_topology_level *tl, |
4a850cbe VK |
7038 | const struct cpumask *cpu_map, struct sched_domain_attr *attr, |
7039 | struct sched_domain *child, int cpu) | |
2c402dc3 | 7040 | { |
143e1e28 | 7041 | struct sched_domain *sd = sd_init(tl, cpu); |
2c402dc3 | 7042 | if (!sd) |
d069b916 | 7043 | return child; |
2c402dc3 | 7044 | |
2c402dc3 | 7045 | cpumask_and(sched_domain_span(sd), cpu_map, tl->mask(cpu)); |
60495e77 PZ |
7046 | if (child) { |
7047 | sd->level = child->level + 1; | |
7048 | sched_domain_level_max = max(sched_domain_level_max, sd->level); | |
d069b916 | 7049 | child->parent = sd; |
c75e0128 | 7050 | sd->child = child; |
6ae72dff PZ |
7051 | |
7052 | if (!cpumask_subset(sched_domain_span(child), | |
7053 | sched_domain_span(sd))) { | |
7054 | pr_err("BUG: arch topology borken\n"); | |
7055 | #ifdef CONFIG_SCHED_DEBUG | |
7056 | pr_err(" the %s domain not a subset of the %s domain\n", | |
7057 | child->name, sd->name); | |
7058 | #endif | |
7059 | /* Fixup, ensure @sd has at least @child cpus. */ | |
7060 | cpumask_or(sched_domain_span(sd), | |
7061 | sched_domain_span(sd), | |
7062 | sched_domain_span(child)); | |
7063 | } | |
7064 | ||
60495e77 | 7065 | } |
a841f8ce | 7066 | set_domain_attribute(sd, attr); |
2c402dc3 PZ |
7067 | |
7068 | return sd; | |
7069 | } | |
7070 | ||
2109b99e AH |
7071 | /* |
7072 | * Build sched domains for a given set of cpus and attach the sched domains | |
7073 | * to the individual cpus | |
7074 | */ | |
dce840a0 PZ |
7075 | static int build_sched_domains(const struct cpumask *cpu_map, |
7076 | struct sched_domain_attr *attr) | |
2109b99e | 7077 | { |
1c632169 | 7078 | enum s_alloc alloc_state; |
dce840a0 | 7079 | struct sched_domain *sd; |
2109b99e | 7080 | struct s_data d; |
822ff793 | 7081 | int i, ret = -ENOMEM; |
9c1cfda2 | 7082 | |
2109b99e AH |
7083 | alloc_state = __visit_domain_allocation_hell(&d, cpu_map); |
7084 | if (alloc_state != sa_rootdomain) | |
7085 | goto error; | |
9c1cfda2 | 7086 | |
dce840a0 | 7087 | /* Set up domains for cpus specified by the cpu_map. */ |
abcd083a | 7088 | for_each_cpu(i, cpu_map) { |
eb7a74e6 PZ |
7089 | struct sched_domain_topology_level *tl; |
7090 | ||
3bd65a80 | 7091 | sd = NULL; |
27723a68 | 7092 | for_each_sd_topology(tl) { |
4a850cbe | 7093 | sd = build_sched_domain(tl, cpu_map, attr, sd, i); |
22da9569 VK |
7094 | if (tl == sched_domain_topology) |
7095 | *per_cpu_ptr(d.sd, i) = sd; | |
e3589f6c PZ |
7096 | if (tl->flags & SDTL_OVERLAP || sched_feat(FORCE_SD_OVERLAP)) |
7097 | sd->flags |= SD_OVERLAP; | |
d110235d PZ |
7098 | if (cpumask_equal(cpu_map, sched_domain_span(sd))) |
7099 | break; | |
e3589f6c | 7100 | } |
dce840a0 PZ |
7101 | } |
7102 | ||
7103 | /* Build the groups for the domains */ | |
7104 | for_each_cpu(i, cpu_map) { | |
7105 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { | |
7106 | sd->span_weight = cpumask_weight(sched_domain_span(sd)); | |
e3589f6c PZ |
7107 | if (sd->flags & SD_OVERLAP) { |
7108 | if (build_overlap_sched_groups(sd, i)) | |
7109 | goto error; | |
7110 | } else { | |
7111 | if (build_sched_groups(sd, i)) | |
7112 | goto error; | |
7113 | } | |
1cf51902 | 7114 | } |
a06dadbe | 7115 | } |
9c1cfda2 | 7116 | |
ced549fa | 7117 | /* Calculate CPU capacity for physical packages and nodes */ |
a9c9a9b6 PZ |
7118 | for (i = nr_cpumask_bits-1; i >= 0; i--) { |
7119 | if (!cpumask_test_cpu(i, cpu_map)) | |
7120 | continue; | |
9c1cfda2 | 7121 | |
dce840a0 PZ |
7122 | for (sd = *per_cpu_ptr(d.sd, i); sd; sd = sd->parent) { |
7123 | claim_allocations(i, sd); | |
63b2ca30 | 7124 | init_sched_groups_capacity(i, sd); |
dce840a0 | 7125 | } |
f712c0c7 | 7126 | } |
9c1cfda2 | 7127 | |
1da177e4 | 7128 | /* Attach the domains */ |
dce840a0 | 7129 | rcu_read_lock(); |
abcd083a | 7130 | for_each_cpu(i, cpu_map) { |
21d42ccf | 7131 | sd = *per_cpu_ptr(d.sd, i); |
49a02c51 | 7132 | cpu_attach_domain(sd, d.rd, i); |
1da177e4 | 7133 | } |
dce840a0 | 7134 | rcu_read_unlock(); |
51888ca2 | 7135 | |
822ff793 | 7136 | ret = 0; |
51888ca2 | 7137 | error: |
2109b99e | 7138 | __free_domain_allocs(&d, alloc_state, cpu_map); |
822ff793 | 7139 | return ret; |
1da177e4 | 7140 | } |
029190c5 | 7141 | |
acc3f5d7 | 7142 | static cpumask_var_t *doms_cur; /* current sched domains */ |
029190c5 | 7143 | static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
4285f594 IM |
7144 | static struct sched_domain_attr *dattr_cur; |
7145 | /* attribues of custom domains in 'doms_cur' */ | |
029190c5 PJ |
7146 | |
7147 | /* | |
7148 | * Special case: If a kmalloc of a doms_cur partition (array of | |
4212823f RR |
7149 | * cpumask) fails, then fallback to a single sched domain, |
7150 | * as determined by the single cpumask fallback_doms. | |
029190c5 | 7151 | */ |
4212823f | 7152 | static cpumask_var_t fallback_doms; |
029190c5 | 7153 | |
ee79d1bd HC |
7154 | /* |
7155 | * arch_update_cpu_topology lets virtualized architectures update the | |
7156 | * cpu core maps. It is supposed to return 1 if the topology changed | |
7157 | * or 0 if it stayed the same. | |
7158 | */ | |
52f5684c | 7159 | int __weak arch_update_cpu_topology(void) |
22e52b07 | 7160 | { |
ee79d1bd | 7161 | return 0; |
22e52b07 HC |
7162 | } |
7163 | ||
acc3f5d7 RR |
7164 | cpumask_var_t *alloc_sched_domains(unsigned int ndoms) |
7165 | { | |
7166 | int i; | |
7167 | cpumask_var_t *doms; | |
7168 | ||
7169 | doms = kmalloc(sizeof(*doms) * ndoms, GFP_KERNEL); | |
7170 | if (!doms) | |
7171 | return NULL; | |
7172 | for (i = 0; i < ndoms; i++) { | |
7173 | if (!alloc_cpumask_var(&doms[i], GFP_KERNEL)) { | |
7174 | free_sched_domains(doms, i); | |
7175 | return NULL; | |
7176 | } | |
7177 | } | |
7178 | return doms; | |
7179 | } | |
7180 | ||
7181 | void free_sched_domains(cpumask_var_t doms[], unsigned int ndoms) | |
7182 | { | |
7183 | unsigned int i; | |
7184 | for (i = 0; i < ndoms; i++) | |
7185 | free_cpumask_var(doms[i]); | |
7186 | kfree(doms); | |
7187 | } | |
7188 | ||
1a20ff27 | 7189 | /* |
41a2d6cf | 7190 | * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
029190c5 PJ |
7191 | * For now this just excludes isolated cpus, but could be used to |
7192 | * exclude other special cases in the future. | |
1a20ff27 | 7193 | */ |
c4a8849a | 7194 | static int init_sched_domains(const struct cpumask *cpu_map) |
1a20ff27 | 7195 | { |
7378547f MM |
7196 | int err; |
7197 | ||
22e52b07 | 7198 | arch_update_cpu_topology(); |
029190c5 | 7199 | ndoms_cur = 1; |
acc3f5d7 | 7200 | doms_cur = alloc_sched_domains(ndoms_cur); |
029190c5 | 7201 | if (!doms_cur) |
acc3f5d7 RR |
7202 | doms_cur = &fallback_doms; |
7203 | cpumask_andnot(doms_cur[0], cpu_map, cpu_isolated_map); | |
dce840a0 | 7204 | err = build_sched_domains(doms_cur[0], NULL); |
6382bc90 | 7205 | register_sched_domain_sysctl(); |
7378547f MM |
7206 | |
7207 | return err; | |
1a20ff27 DG |
7208 | } |
7209 | ||
1a20ff27 DG |
7210 | /* |
7211 | * Detach sched domains from a group of cpus specified in cpu_map | |
7212 | * These cpus will now be attached to the NULL domain | |
7213 | */ | |
96f874e2 | 7214 | static void detach_destroy_domains(const struct cpumask *cpu_map) |
1a20ff27 DG |
7215 | { |
7216 | int i; | |
7217 | ||
dce840a0 | 7218 | rcu_read_lock(); |
abcd083a | 7219 | for_each_cpu(i, cpu_map) |
57d885fe | 7220 | cpu_attach_domain(NULL, &def_root_domain, i); |
dce840a0 | 7221 | rcu_read_unlock(); |
1a20ff27 DG |
7222 | } |
7223 | ||
1d3504fc HS |
7224 | /* handle null as "default" */ |
7225 | static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, | |
7226 | struct sched_domain_attr *new, int idx_new) | |
7227 | { | |
7228 | struct sched_domain_attr tmp; | |
7229 | ||
7230 | /* fast path */ | |
7231 | if (!new && !cur) | |
7232 | return 1; | |
7233 | ||
7234 | tmp = SD_ATTR_INIT; | |
7235 | return !memcmp(cur ? (cur + idx_cur) : &tmp, | |
7236 | new ? (new + idx_new) : &tmp, | |
7237 | sizeof(struct sched_domain_attr)); | |
7238 | } | |
7239 | ||
029190c5 PJ |
7240 | /* |
7241 | * Partition sched domains as specified by the 'ndoms_new' | |
41a2d6cf | 7242 | * cpumasks in the array doms_new[] of cpumasks. This compares |
029190c5 PJ |
7243 | * doms_new[] to the current sched domain partitioning, doms_cur[]. |
7244 | * It destroys each deleted domain and builds each new domain. | |
7245 | * | |
acc3f5d7 | 7246 | * 'doms_new' is an array of cpumask_var_t's of length 'ndoms_new'. |
41a2d6cf IM |
7247 | * The masks don't intersect (don't overlap.) We should setup one |
7248 | * sched domain for each mask. CPUs not in any of the cpumasks will | |
7249 | * not be load balanced. If the same cpumask appears both in the | |
029190c5 PJ |
7250 | * current 'doms_cur' domains and in the new 'doms_new', we can leave |
7251 | * it as it is. | |
7252 | * | |
acc3f5d7 RR |
7253 | * The passed in 'doms_new' should be allocated using |
7254 | * alloc_sched_domains. This routine takes ownership of it and will | |
7255 | * free_sched_domains it when done with it. If the caller failed the | |
7256 | * alloc call, then it can pass in doms_new == NULL && ndoms_new == 1, | |
7257 | * and partition_sched_domains() will fallback to the single partition | |
7258 | * 'fallback_doms', it also forces the domains to be rebuilt. | |
029190c5 | 7259 | * |
96f874e2 | 7260 | * If doms_new == NULL it will be replaced with cpu_online_mask. |
700018e0 LZ |
7261 | * ndoms_new == 0 is a special case for destroying existing domains, |
7262 | * and it will not create the default domain. | |
dfb512ec | 7263 | * |
029190c5 PJ |
7264 | * Call with hotplug lock held |
7265 | */ | |
acc3f5d7 | 7266 | void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[], |
1d3504fc | 7267 | struct sched_domain_attr *dattr_new) |
029190c5 | 7268 | { |
dfb512ec | 7269 | int i, j, n; |
d65bd5ec | 7270 | int new_topology; |
029190c5 | 7271 | |
712555ee | 7272 | mutex_lock(&sched_domains_mutex); |
a1835615 | 7273 | |
7378547f MM |
7274 | /* always unregister in case we don't destroy any domains */ |
7275 | unregister_sched_domain_sysctl(); | |
7276 | ||
d65bd5ec HC |
7277 | /* Let architecture update cpu core mappings. */ |
7278 | new_topology = arch_update_cpu_topology(); | |
7279 | ||
dfb512ec | 7280 | n = doms_new ? ndoms_new : 0; |
029190c5 PJ |
7281 | |
7282 | /* Destroy deleted domains */ | |
7283 | for (i = 0; i < ndoms_cur; i++) { | |
d65bd5ec | 7284 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 7285 | if (cpumask_equal(doms_cur[i], doms_new[j]) |
1d3504fc | 7286 | && dattrs_equal(dattr_cur, i, dattr_new, j)) |
029190c5 PJ |
7287 | goto match1; |
7288 | } | |
7289 | /* no match - a current sched domain not in new doms_new[] */ | |
acc3f5d7 | 7290 | detach_destroy_domains(doms_cur[i]); |
029190c5 PJ |
7291 | match1: |
7292 | ; | |
7293 | } | |
7294 | ||
c8d2d47a | 7295 | n = ndoms_cur; |
e761b772 | 7296 | if (doms_new == NULL) { |
c8d2d47a | 7297 | n = 0; |
acc3f5d7 | 7298 | doms_new = &fallback_doms; |
6ad4c188 | 7299 | cpumask_andnot(doms_new[0], cpu_active_mask, cpu_isolated_map); |
faa2f98f | 7300 | WARN_ON_ONCE(dattr_new); |
e761b772 MK |
7301 | } |
7302 | ||
029190c5 PJ |
7303 | /* Build new domains */ |
7304 | for (i = 0; i < ndoms_new; i++) { | |
c8d2d47a | 7305 | for (j = 0; j < n && !new_topology; j++) { |
acc3f5d7 | 7306 | if (cpumask_equal(doms_new[i], doms_cur[j]) |
1d3504fc | 7307 | && dattrs_equal(dattr_new, i, dattr_cur, j)) |
029190c5 PJ |
7308 | goto match2; |
7309 | } | |
7310 | /* no match - add a new doms_new */ | |
dce840a0 | 7311 | build_sched_domains(doms_new[i], dattr_new ? dattr_new + i : NULL); |
029190c5 PJ |
7312 | match2: |
7313 | ; | |
7314 | } | |
7315 | ||
7316 | /* Remember the new sched domains */ | |
acc3f5d7 RR |
7317 | if (doms_cur != &fallback_doms) |
7318 | free_sched_domains(doms_cur, ndoms_cur); | |
1d3504fc | 7319 | kfree(dattr_cur); /* kfree(NULL) is safe */ |
029190c5 | 7320 | doms_cur = doms_new; |
1d3504fc | 7321 | dattr_cur = dattr_new; |
029190c5 | 7322 | ndoms_cur = ndoms_new; |
7378547f MM |
7323 | |
7324 | register_sched_domain_sysctl(); | |
a1835615 | 7325 | |
712555ee | 7326 | mutex_unlock(&sched_domains_mutex); |
029190c5 PJ |
7327 | } |
7328 | ||
d35be8ba SB |
7329 | static int num_cpus_frozen; /* used to mark begin/end of suspend/resume */ |
7330 | ||
1da177e4 | 7331 | /* |
3a101d05 TH |
7332 | * Update cpusets according to cpu_active mask. If cpusets are |
7333 | * disabled, cpuset_update_active_cpus() becomes a simple wrapper | |
7334 | * around partition_sched_domains(). | |
d35be8ba SB |
7335 | * |
7336 | * If we come here as part of a suspend/resume, don't touch cpusets because we | |
7337 | * want to restore it back to its original state upon resume anyway. | |
1da177e4 | 7338 | */ |
0b2e918a TH |
7339 | static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, |
7340 | void *hcpu) | |
e761b772 | 7341 | { |
d35be8ba SB |
7342 | switch (action) { |
7343 | case CPU_ONLINE_FROZEN: | |
7344 | case CPU_DOWN_FAILED_FROZEN: | |
7345 | ||
7346 | /* | |
7347 | * num_cpus_frozen tracks how many CPUs are involved in suspend | |
7348 | * resume sequence. As long as this is not the last online | |
7349 | * operation in the resume sequence, just build a single sched | |
7350 | * domain, ignoring cpusets. | |
7351 | */ | |
7352 | num_cpus_frozen--; | |
7353 | if (likely(num_cpus_frozen)) { | |
7354 | partition_sched_domains(1, NULL, NULL); | |
7355 | break; | |
7356 | } | |
7357 | ||
7358 | /* | |
7359 | * This is the last CPU online operation. So fall through and | |
7360 | * restore the original sched domains by considering the | |
7361 | * cpuset configurations. | |
7362 | */ | |
7363 | ||
e761b772 | 7364 | case CPU_ONLINE: |
7ddf96b0 | 7365 | cpuset_update_active_cpus(true); |
d35be8ba | 7366 | break; |
3a101d05 TH |
7367 | default: |
7368 | return NOTIFY_DONE; | |
7369 | } | |
d35be8ba | 7370 | return NOTIFY_OK; |
3a101d05 | 7371 | } |
e761b772 | 7372 | |
0b2e918a TH |
7373 | static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, |
7374 | void *hcpu) | |
3a101d05 | 7375 | { |
3c18d447 JL |
7376 | unsigned long flags; |
7377 | long cpu = (long)hcpu; | |
7378 | struct dl_bw *dl_b; | |
533445c6 OS |
7379 | bool overflow; |
7380 | int cpus; | |
3c18d447 | 7381 | |
533445c6 | 7382 | switch (action) { |
3a101d05 | 7383 | case CPU_DOWN_PREPARE: |
533445c6 OS |
7384 | rcu_read_lock_sched(); |
7385 | dl_b = dl_bw_of(cpu); | |
3c18d447 | 7386 | |
533445c6 OS |
7387 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
7388 | cpus = dl_bw_cpus(cpu); | |
7389 | overflow = __dl_overflow(dl_b, cpus, 0, 0); | |
7390 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); | |
3c18d447 | 7391 | |
533445c6 | 7392 | rcu_read_unlock_sched(); |
3c18d447 | 7393 | |
533445c6 OS |
7394 | if (overflow) |
7395 | return notifier_from_errno(-EBUSY); | |
7ddf96b0 | 7396 | cpuset_update_active_cpus(false); |
d35be8ba SB |
7397 | break; |
7398 | case CPU_DOWN_PREPARE_FROZEN: | |
7399 | num_cpus_frozen++; | |
7400 | partition_sched_domains(1, NULL, NULL); | |
7401 | break; | |
e761b772 MK |
7402 | default: |
7403 | return NOTIFY_DONE; | |
7404 | } | |
d35be8ba | 7405 | return NOTIFY_OK; |
e761b772 | 7406 | } |
e761b772 | 7407 | |
1da177e4 LT |
7408 | void __init sched_init_smp(void) |
7409 | { | |
dcc30a35 RR |
7410 | cpumask_var_t non_isolated_cpus; |
7411 | ||
7412 | alloc_cpumask_var(&non_isolated_cpus, GFP_KERNEL); | |
cb5fd13f | 7413 | alloc_cpumask_var(&fallback_doms, GFP_KERNEL); |
5c1e1767 | 7414 | |
cb83b629 PZ |
7415 | sched_init_numa(); |
7416 | ||
6acce3ef PZ |
7417 | /* |
7418 | * There's no userspace yet to cause hotplug operations; hence all the | |
7419 | * cpu masks are stable and all blatant races in the below code cannot | |
7420 | * happen. | |
7421 | */ | |
712555ee | 7422 | mutex_lock(&sched_domains_mutex); |
c4a8849a | 7423 | init_sched_domains(cpu_active_mask); |
dcc30a35 RR |
7424 | cpumask_andnot(non_isolated_cpus, cpu_possible_mask, cpu_isolated_map); |
7425 | if (cpumask_empty(non_isolated_cpus)) | |
7426 | cpumask_set_cpu(smp_processor_id(), non_isolated_cpus); | |
712555ee | 7427 | mutex_unlock(&sched_domains_mutex); |
e761b772 | 7428 | |
301a5cba | 7429 | hotcpu_notifier(sched_domains_numa_masks_update, CPU_PRI_SCHED_ACTIVE); |
3a101d05 TH |
7430 | hotcpu_notifier(cpuset_cpu_active, CPU_PRI_CPUSET_ACTIVE); |
7431 | hotcpu_notifier(cpuset_cpu_inactive, CPU_PRI_CPUSET_INACTIVE); | |
e761b772 | 7432 | |
b328ca18 | 7433 | init_hrtick(); |
5c1e1767 NP |
7434 | |
7435 | /* Move init over to a non-isolated CPU */ | |
dcc30a35 | 7436 | if (set_cpus_allowed_ptr(current, non_isolated_cpus) < 0) |
5c1e1767 | 7437 | BUG(); |
19978ca6 | 7438 | sched_init_granularity(); |
dcc30a35 | 7439 | free_cpumask_var(non_isolated_cpus); |
4212823f | 7440 | |
0e3900e6 | 7441 | init_sched_rt_class(); |
1baca4ce | 7442 | init_sched_dl_class(); |
1da177e4 LT |
7443 | } |
7444 | #else | |
7445 | void __init sched_init_smp(void) | |
7446 | { | |
19978ca6 | 7447 | sched_init_granularity(); |
1da177e4 LT |
7448 | } |
7449 | #endif /* CONFIG_SMP */ | |
7450 | ||
7451 | int in_sched_functions(unsigned long addr) | |
7452 | { | |
1da177e4 LT |
7453 | return in_lock_functions(addr) || |
7454 | (addr >= (unsigned long)__sched_text_start | |
7455 | && addr < (unsigned long)__sched_text_end); | |
7456 | } | |
7457 | ||
029632fb | 7458 | #ifdef CONFIG_CGROUP_SCHED |
27b4b931 LZ |
7459 | /* |
7460 | * Default task group. | |
7461 | * Every task in system belongs to this group at bootup. | |
7462 | */ | |
029632fb | 7463 | struct task_group root_task_group; |
35cf4e50 | 7464 | LIST_HEAD(task_groups); |
b0367629 WL |
7465 | |
7466 | /* Cacheline aligned slab cache for task_group */ | |
7467 | static struct kmem_cache *task_group_cache __read_mostly; | |
052f1dc7 | 7468 | #endif |
6f505b16 | 7469 | |
e6252c3e | 7470 | DECLARE_PER_CPU(cpumask_var_t, load_balance_mask); |
6f505b16 | 7471 | |
1da177e4 LT |
7472 | void __init sched_init(void) |
7473 | { | |
dd41f596 | 7474 | int i, j; |
434d53b0 MT |
7475 | unsigned long alloc_size = 0, ptr; |
7476 | ||
7477 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
7478 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
7479 | #endif | |
7480 | #ifdef CONFIG_RT_GROUP_SCHED | |
7481 | alloc_size += 2 * nr_cpu_ids * sizeof(void **); | |
7482 | #endif | |
434d53b0 | 7483 | if (alloc_size) { |
36b7b6d4 | 7484 | ptr = (unsigned long)kzalloc(alloc_size, GFP_NOWAIT); |
434d53b0 MT |
7485 | |
7486 | #ifdef CONFIG_FAIR_GROUP_SCHED | |
07e06b01 | 7487 | root_task_group.se = (struct sched_entity **)ptr; |
434d53b0 MT |
7488 | ptr += nr_cpu_ids * sizeof(void **); |
7489 | ||
07e06b01 | 7490 | root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
434d53b0 | 7491 | ptr += nr_cpu_ids * sizeof(void **); |
eff766a6 | 7492 | |
6d6bc0ad | 7493 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
434d53b0 | 7494 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7495 | root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
434d53b0 MT |
7496 | ptr += nr_cpu_ids * sizeof(void **); |
7497 | ||
07e06b01 | 7498 | root_task_group.rt_rq = (struct rt_rq **)ptr; |
eff766a6 PZ |
7499 | ptr += nr_cpu_ids * sizeof(void **); |
7500 | ||
6d6bc0ad | 7501 | #endif /* CONFIG_RT_GROUP_SCHED */ |
b74e6278 | 7502 | } |
df7c8e84 | 7503 | #ifdef CONFIG_CPUMASK_OFFSTACK |
b74e6278 AT |
7504 | for_each_possible_cpu(i) { |
7505 | per_cpu(load_balance_mask, i) = (cpumask_var_t)kzalloc_node( | |
7506 | cpumask_size(), GFP_KERNEL, cpu_to_node(i)); | |
434d53b0 | 7507 | } |
b74e6278 | 7508 | #endif /* CONFIG_CPUMASK_OFFSTACK */ |
dd41f596 | 7509 | |
332ac17e DF |
7510 | init_rt_bandwidth(&def_rt_bandwidth, |
7511 | global_rt_period(), global_rt_runtime()); | |
7512 | init_dl_bandwidth(&def_dl_bandwidth, | |
1724813d | 7513 | global_rt_period(), global_rt_runtime()); |
332ac17e | 7514 | |
57d885fe GH |
7515 | #ifdef CONFIG_SMP |
7516 | init_defrootdomain(); | |
7517 | #endif | |
7518 | ||
d0b27fa7 | 7519 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7520 | init_rt_bandwidth(&root_task_group.rt_bandwidth, |
d0b27fa7 | 7521 | global_rt_period(), global_rt_runtime()); |
6d6bc0ad | 7522 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 7523 | |
7c941438 | 7524 | #ifdef CONFIG_CGROUP_SCHED |
b0367629 WL |
7525 | task_group_cache = KMEM_CACHE(task_group, 0); |
7526 | ||
07e06b01 YZ |
7527 | list_add(&root_task_group.list, &task_groups); |
7528 | INIT_LIST_HEAD(&root_task_group.children); | |
f4d6f6c2 | 7529 | INIT_LIST_HEAD(&root_task_group.siblings); |
5091faa4 | 7530 | autogroup_init(&init_task); |
7c941438 | 7531 | #endif /* CONFIG_CGROUP_SCHED */ |
6f505b16 | 7532 | |
0a945022 | 7533 | for_each_possible_cpu(i) { |
70b97a7f | 7534 | struct rq *rq; |
1da177e4 LT |
7535 | |
7536 | rq = cpu_rq(i); | |
05fa785c | 7537 | raw_spin_lock_init(&rq->lock); |
7897986b | 7538 | rq->nr_running = 0; |
dce48a84 TG |
7539 | rq->calc_load_active = 0; |
7540 | rq->calc_load_update = jiffies + LOAD_FREQ; | |
acb5a9ba | 7541 | init_cfs_rq(&rq->cfs); |
07c54f7a AV |
7542 | init_rt_rq(&rq->rt); |
7543 | init_dl_rq(&rq->dl); | |
dd41f596 | 7544 | #ifdef CONFIG_FAIR_GROUP_SCHED |
029632fb | 7545 | root_task_group.shares = ROOT_TASK_GROUP_LOAD; |
6f505b16 | 7546 | INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
354d60c2 | 7547 | /* |
07e06b01 | 7548 | * How much cpu bandwidth does root_task_group get? |
354d60c2 DG |
7549 | * |
7550 | * In case of task-groups formed thr' the cgroup filesystem, it | |
7551 | * gets 100% of the cpu resources in the system. This overall | |
7552 | * system cpu resource is divided among the tasks of | |
07e06b01 | 7553 | * root_task_group and its child task-groups in a fair manner, |
354d60c2 DG |
7554 | * based on each entity's (task or task-group's) weight |
7555 | * (se->load.weight). | |
7556 | * | |
07e06b01 | 7557 | * In other words, if root_task_group has 10 tasks of weight |
354d60c2 DG |
7558 | * 1024) and two child groups A0 and A1 (of weight 1024 each), |
7559 | * then A0's share of the cpu resource is: | |
7560 | * | |
0d905bca | 7561 | * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
354d60c2 | 7562 | * |
07e06b01 YZ |
7563 | * We achieve this by letting root_task_group's tasks sit |
7564 | * directly in rq->cfs (i.e root_task_group->se[] = NULL). | |
354d60c2 | 7565 | */ |
ab84d31e | 7566 | init_cfs_bandwidth(&root_task_group.cfs_bandwidth); |
07e06b01 | 7567 | init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, NULL); |
354d60c2 DG |
7568 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
7569 | ||
7570 | rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; | |
052f1dc7 | 7571 | #ifdef CONFIG_RT_GROUP_SCHED |
07e06b01 | 7572 | init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, NULL); |
dd41f596 | 7573 | #endif |
1da177e4 | 7574 | |
dd41f596 IM |
7575 | for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
7576 | rq->cpu_load[j] = 0; | |
fdf3e95d VP |
7577 | |
7578 | rq->last_load_update_tick = jiffies; | |
7579 | ||
1da177e4 | 7580 | #ifdef CONFIG_SMP |
41c7ce9a | 7581 | rq->sd = NULL; |
57d885fe | 7582 | rq->rd = NULL; |
ca6d75e6 | 7583 | rq->cpu_capacity = rq->cpu_capacity_orig = SCHED_CAPACITY_SCALE; |
e3fca9e7 | 7584 | rq->balance_callback = NULL; |
1da177e4 | 7585 | rq->active_balance = 0; |
dd41f596 | 7586 | rq->next_balance = jiffies; |
1da177e4 | 7587 | rq->push_cpu = 0; |
0a2966b4 | 7588 | rq->cpu = i; |
1f11eb6a | 7589 | rq->online = 0; |
eae0c9df MG |
7590 | rq->idle_stamp = 0; |
7591 | rq->avg_idle = 2*sysctl_sched_migration_cost; | |
9bd721c5 | 7592 | rq->max_idle_balance_cost = sysctl_sched_migration_cost; |
367456c7 PZ |
7593 | |
7594 | INIT_LIST_HEAD(&rq->cfs_tasks); | |
7595 | ||
dc938520 | 7596 | rq_attach_root(rq, &def_root_domain); |
3451d024 | 7597 | #ifdef CONFIG_NO_HZ_COMMON |
1c792db7 | 7598 | rq->nohz_flags = 0; |
83cd4fe2 | 7599 | #endif |
265f22a9 FW |
7600 | #ifdef CONFIG_NO_HZ_FULL |
7601 | rq->last_sched_tick = 0; | |
7602 | #endif | |
1da177e4 | 7603 | #endif |
8f4d37ec | 7604 | init_rq_hrtick(rq); |
1da177e4 | 7605 | atomic_set(&rq->nr_iowait, 0); |
1da177e4 LT |
7606 | } |
7607 | ||
2dd73a4f | 7608 | set_load_weight(&init_task); |
b50f60ce | 7609 | |
e107be36 AK |
7610 | #ifdef CONFIG_PREEMPT_NOTIFIERS |
7611 | INIT_HLIST_HEAD(&init_task.preempt_notifiers); | |
7612 | #endif | |
7613 | ||
1da177e4 LT |
7614 | /* |
7615 | * The boot idle thread does lazy MMU switching as well: | |
7616 | */ | |
7617 | atomic_inc(&init_mm.mm_count); | |
7618 | enter_lazy_tlb(&init_mm, current); | |
7619 | ||
1b537c7d YD |
7620 | /* |
7621 | * During early bootup we pretend to be a normal task: | |
7622 | */ | |
7623 | current->sched_class = &fair_sched_class; | |
7624 | ||
1da177e4 LT |
7625 | /* |
7626 | * Make us the idle thread. Technically, schedule() should not be | |
7627 | * called from this thread, however somewhere below it might be, | |
7628 | * but because we are the idle thread, we just pick up running again | |
7629 | * when this runqueue becomes "idle". | |
7630 | */ | |
7631 | init_idle(current, smp_processor_id()); | |
dce48a84 TG |
7632 | |
7633 | calc_load_update = jiffies + LOAD_FREQ; | |
7634 | ||
bf4d83f6 | 7635 | #ifdef CONFIG_SMP |
4cb98839 | 7636 | zalloc_cpumask_var(&sched_domains_tmpmask, GFP_NOWAIT); |
bdddd296 RR |
7637 | /* May be allocated at isolcpus cmdline parse time */ |
7638 | if (cpu_isolated_map == NULL) | |
7639 | zalloc_cpumask_var(&cpu_isolated_map, GFP_NOWAIT); | |
29d5e047 | 7640 | idle_thread_set_boot_cpu(); |
a803f026 | 7641 | set_cpu_rq_start_time(); |
029632fb PZ |
7642 | #endif |
7643 | init_sched_fair_class(); | |
6a7b3dc3 | 7644 | |
6892b75e | 7645 | scheduler_running = 1; |
1da177e4 LT |
7646 | } |
7647 | ||
d902db1e | 7648 | #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
e4aafea2 FW |
7649 | static inline int preempt_count_equals(int preempt_offset) |
7650 | { | |
da7142e2 | 7651 | int nested = preempt_count() + rcu_preempt_depth(); |
e4aafea2 | 7652 | |
4ba8216c | 7653 | return (nested == preempt_offset); |
e4aafea2 FW |
7654 | } |
7655 | ||
d894837f | 7656 | void __might_sleep(const char *file, int line, int preempt_offset) |
1da177e4 | 7657 | { |
8eb23b9f PZ |
7658 | /* |
7659 | * Blocking primitives will set (and therefore destroy) current->state, | |
7660 | * since we will exit with TASK_RUNNING make sure we enter with it, | |
7661 | * otherwise we will destroy state. | |
7662 | */ | |
00845eb9 | 7663 | WARN_ONCE(current->state != TASK_RUNNING && current->task_state_change, |
8eb23b9f PZ |
7664 | "do not call blocking ops when !TASK_RUNNING; " |
7665 | "state=%lx set at [<%p>] %pS\n", | |
7666 | current->state, | |
7667 | (void *)current->task_state_change, | |
00845eb9 | 7668 | (void *)current->task_state_change); |
8eb23b9f | 7669 | |
3427445a PZ |
7670 | ___might_sleep(file, line, preempt_offset); |
7671 | } | |
7672 | EXPORT_SYMBOL(__might_sleep); | |
7673 | ||
7674 | void ___might_sleep(const char *file, int line, int preempt_offset) | |
1da177e4 | 7675 | { |
1da177e4 LT |
7676 | static unsigned long prev_jiffy; /* ratelimiting */ |
7677 | ||
b3fbab05 | 7678 | rcu_sleep_check(); /* WARN_ON_ONCE() by default, no rate limit reqd. */ |
db273be2 TG |
7679 | if ((preempt_count_equals(preempt_offset) && !irqs_disabled() && |
7680 | !is_idle_task(current)) || | |
e4aafea2 | 7681 | system_state != SYSTEM_RUNNING || oops_in_progress) |
aef745fc IM |
7682 | return; |
7683 | if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) | |
7684 | return; | |
7685 | prev_jiffy = jiffies; | |
7686 | ||
3df0fc5b PZ |
7687 | printk(KERN_ERR |
7688 | "BUG: sleeping function called from invalid context at %s:%d\n", | |
7689 | file, line); | |
7690 | printk(KERN_ERR | |
7691 | "in_atomic(): %d, irqs_disabled(): %d, pid: %d, name: %s\n", | |
7692 | in_atomic(), irqs_disabled(), | |
7693 | current->pid, current->comm); | |
aef745fc | 7694 | |
a8b686b3 ES |
7695 | if (task_stack_end_corrupted(current)) |
7696 | printk(KERN_EMERG "Thread overran stack, or stack corrupted\n"); | |
7697 | ||
aef745fc IM |
7698 | debug_show_held_locks(current); |
7699 | if (irqs_disabled()) | |
7700 | print_irqtrace_events(current); | |
8f47b187 TG |
7701 | #ifdef CONFIG_DEBUG_PREEMPT |
7702 | if (!preempt_count_equals(preempt_offset)) { | |
7703 | pr_err("Preemption disabled at:"); | |
7704 | print_ip_sym(current->preempt_disable_ip); | |
7705 | pr_cont("\n"); | |
7706 | } | |
7707 | #endif | |
aef745fc | 7708 | dump_stack(); |
1da177e4 | 7709 | } |
3427445a | 7710 | EXPORT_SYMBOL(___might_sleep); |
1da177e4 LT |
7711 | #endif |
7712 | ||
7713 | #ifdef CONFIG_MAGIC_SYSRQ | |
dbc7f069 | 7714 | void normalize_rt_tasks(void) |
3a5e4dc1 | 7715 | { |
dbc7f069 | 7716 | struct task_struct *g, *p; |
d50dde5a DF |
7717 | struct sched_attr attr = { |
7718 | .sched_policy = SCHED_NORMAL, | |
7719 | }; | |
1da177e4 | 7720 | |
3472eaa1 | 7721 | read_lock(&tasklist_lock); |
5d07f420 | 7722 | for_each_process_thread(g, p) { |
178be793 IM |
7723 | /* |
7724 | * Only normalize user tasks: | |
7725 | */ | |
3472eaa1 | 7726 | if (p->flags & PF_KTHREAD) |
178be793 IM |
7727 | continue; |
7728 | ||
6cfb0d5d | 7729 | p->se.exec_start = 0; |
6cfb0d5d | 7730 | #ifdef CONFIG_SCHEDSTATS |
41acab88 LDM |
7731 | p->se.statistics.wait_start = 0; |
7732 | p->se.statistics.sleep_start = 0; | |
7733 | p->se.statistics.block_start = 0; | |
6cfb0d5d | 7734 | #endif |
dd41f596 | 7735 | |
aab03e05 | 7736 | if (!dl_task(p) && !rt_task(p)) { |
dd41f596 IM |
7737 | /* |
7738 | * Renice negative nice level userspace | |
7739 | * tasks back to 0: | |
7740 | */ | |
3472eaa1 | 7741 | if (task_nice(p) < 0) |
dd41f596 | 7742 | set_user_nice(p, 0); |
1da177e4 | 7743 | continue; |
dd41f596 | 7744 | } |
1da177e4 | 7745 | |
dbc7f069 | 7746 | __sched_setscheduler(p, &attr, false, false); |
5d07f420 | 7747 | } |
3472eaa1 | 7748 | read_unlock(&tasklist_lock); |
1da177e4 LT |
7749 | } |
7750 | ||
7751 | #endif /* CONFIG_MAGIC_SYSRQ */ | |
1df5c10a | 7752 | |
67fc4e0c | 7753 | #if defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) |
1df5c10a | 7754 | /* |
67fc4e0c | 7755 | * These functions are only useful for the IA64 MCA handling, or kdb. |
1df5c10a LT |
7756 | * |
7757 | * They can only be called when the whole system has been | |
7758 | * stopped - every CPU needs to be quiescent, and no scheduling | |
7759 | * activity can take place. Using them for anything else would | |
7760 | * be a serious bug, and as a result, they aren't even visible | |
7761 | * under any other configuration. | |
7762 | */ | |
7763 | ||
7764 | /** | |
7765 | * curr_task - return the current task for a given cpu. | |
7766 | * @cpu: the processor in question. | |
7767 | * | |
7768 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
e69f6186 YB |
7769 | * |
7770 | * Return: The current task for @cpu. | |
1df5c10a | 7771 | */ |
36c8b586 | 7772 | struct task_struct *curr_task(int cpu) |
1df5c10a LT |
7773 | { |
7774 | return cpu_curr(cpu); | |
7775 | } | |
7776 | ||
67fc4e0c JW |
7777 | #endif /* defined(CONFIG_IA64) || defined(CONFIG_KGDB_KDB) */ |
7778 | ||
7779 | #ifdef CONFIG_IA64 | |
1df5c10a LT |
7780 | /** |
7781 | * set_curr_task - set the current task for a given cpu. | |
7782 | * @cpu: the processor in question. | |
7783 | * @p: the task pointer to set. | |
7784 | * | |
7785 | * Description: This function must only be used when non-maskable interrupts | |
41a2d6cf IM |
7786 | * are serviced on a separate stack. It allows the architecture to switch the |
7787 | * notion of the current task on a cpu in a non-blocking manner. This function | |
1df5c10a LT |
7788 | * must be called with all CPU's synchronized, and interrupts disabled, the |
7789 | * and caller must save the original value of the current task (see | |
7790 | * curr_task() above) and restore that value before reenabling interrupts and | |
7791 | * re-starting the system. | |
7792 | * | |
7793 | * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! | |
7794 | */ | |
36c8b586 | 7795 | void set_curr_task(int cpu, struct task_struct *p) |
1df5c10a LT |
7796 | { |
7797 | cpu_curr(cpu) = p; | |
7798 | } | |
7799 | ||
7800 | #endif | |
29f59db3 | 7801 | |
7c941438 | 7802 | #ifdef CONFIG_CGROUP_SCHED |
029632fb PZ |
7803 | /* task_group_lock serializes the addition/removal of task groups */ |
7804 | static DEFINE_SPINLOCK(task_group_lock); | |
7805 | ||
bccbe08a PZ |
7806 | static void free_sched_group(struct task_group *tg) |
7807 | { | |
7808 | free_fair_sched_group(tg); | |
7809 | free_rt_sched_group(tg); | |
e9aa1dd1 | 7810 | autogroup_free(tg); |
b0367629 | 7811 | kmem_cache_free(task_group_cache, tg); |
bccbe08a PZ |
7812 | } |
7813 | ||
7814 | /* allocate runqueue etc for a new task group */ | |
ec7dc8ac | 7815 | struct task_group *sched_create_group(struct task_group *parent) |
bccbe08a PZ |
7816 | { |
7817 | struct task_group *tg; | |
bccbe08a | 7818 | |
b0367629 | 7819 | tg = kmem_cache_alloc(task_group_cache, GFP_KERNEL | __GFP_ZERO); |
bccbe08a PZ |
7820 | if (!tg) |
7821 | return ERR_PTR(-ENOMEM); | |
7822 | ||
ec7dc8ac | 7823 | if (!alloc_fair_sched_group(tg, parent)) |
bccbe08a PZ |
7824 | goto err; |
7825 | ||
ec7dc8ac | 7826 | if (!alloc_rt_sched_group(tg, parent)) |
bccbe08a PZ |
7827 | goto err; |
7828 | ||
ace783b9 LZ |
7829 | return tg; |
7830 | ||
7831 | err: | |
7832 | free_sched_group(tg); | |
7833 | return ERR_PTR(-ENOMEM); | |
7834 | } | |
7835 | ||
7836 | void sched_online_group(struct task_group *tg, struct task_group *parent) | |
7837 | { | |
7838 | unsigned long flags; | |
7839 | ||
8ed36996 | 7840 | spin_lock_irqsave(&task_group_lock, flags); |
6f505b16 | 7841 | list_add_rcu(&tg->list, &task_groups); |
f473aa5e PZ |
7842 | |
7843 | WARN_ON(!parent); /* root should already exist */ | |
7844 | ||
7845 | tg->parent = parent; | |
f473aa5e | 7846 | INIT_LIST_HEAD(&tg->children); |
09f2724a | 7847 | list_add_rcu(&tg->siblings, &parent->children); |
8ed36996 | 7848 | spin_unlock_irqrestore(&task_group_lock, flags); |
29f59db3 SV |
7849 | } |
7850 | ||
9b5b7751 | 7851 | /* rcu callback to free various structures associated with a task group */ |
6f505b16 | 7852 | static void free_sched_group_rcu(struct rcu_head *rhp) |
29f59db3 | 7853 | { |
29f59db3 | 7854 | /* now it should be safe to free those cfs_rqs */ |
6f505b16 | 7855 | free_sched_group(container_of(rhp, struct task_group, rcu)); |
29f59db3 SV |
7856 | } |
7857 | ||
9b5b7751 | 7858 | /* Destroy runqueue etc associated with a task group */ |
4cf86d77 | 7859 | void sched_destroy_group(struct task_group *tg) |
ace783b9 LZ |
7860 | { |
7861 | /* wait for possible concurrent references to cfs_rqs complete */ | |
7862 | call_rcu(&tg->rcu, free_sched_group_rcu); | |
7863 | } | |
7864 | ||
7865 | void sched_offline_group(struct task_group *tg) | |
29f59db3 | 7866 | { |
8ed36996 | 7867 | unsigned long flags; |
9b5b7751 | 7868 | int i; |
29f59db3 | 7869 | |
3d4b47b4 PZ |
7870 | /* end participation in shares distribution */ |
7871 | for_each_possible_cpu(i) | |
bccbe08a | 7872 | unregister_fair_sched_group(tg, i); |
3d4b47b4 PZ |
7873 | |
7874 | spin_lock_irqsave(&task_group_lock, flags); | |
6f505b16 | 7875 | list_del_rcu(&tg->list); |
f473aa5e | 7876 | list_del_rcu(&tg->siblings); |
8ed36996 | 7877 | spin_unlock_irqrestore(&task_group_lock, flags); |
29f59db3 SV |
7878 | } |
7879 | ||
9b5b7751 | 7880 | /* change task's runqueue when it moves between groups. |
3a252015 IM |
7881 | * The caller of this function should have put the task in its new group |
7882 | * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to | |
7883 | * reflect its new group. | |
9b5b7751 SV |
7884 | */ |
7885 | void sched_move_task(struct task_struct *tsk) | |
29f59db3 | 7886 | { |
8323f26c | 7887 | struct task_group *tg; |
da0c1e65 | 7888 | int queued, running; |
29f59db3 SV |
7889 | unsigned long flags; |
7890 | struct rq *rq; | |
7891 | ||
7892 | rq = task_rq_lock(tsk, &flags); | |
7893 | ||
051a1d1a | 7894 | running = task_current(rq, tsk); |
da0c1e65 | 7895 | queued = task_on_rq_queued(tsk); |
29f59db3 | 7896 | |
da0c1e65 | 7897 | if (queued) |
1de64443 | 7898 | dequeue_task(rq, tsk, DEQUEUE_SAVE); |
0e1f3483 | 7899 | if (unlikely(running)) |
f3cd1c4e | 7900 | put_prev_task(rq, tsk); |
29f59db3 | 7901 | |
f7b8a47d KT |
7902 | /* |
7903 | * All callers are synchronized by task_rq_lock(); we do not use RCU | |
7904 | * which is pointless here. Thus, we pass "true" to task_css_check() | |
7905 | * to prevent lockdep warnings. | |
7906 | */ | |
7907 | tg = container_of(task_css_check(tsk, cpu_cgrp_id, true), | |
8323f26c PZ |
7908 | struct task_group, css); |
7909 | tg = autogroup_task_group(tsk, tg); | |
7910 | tsk->sched_task_group = tg; | |
7911 | ||
810b3817 | 7912 | #ifdef CONFIG_FAIR_GROUP_SCHED |
b2b5ce02 | 7913 | if (tsk->sched_class->task_move_group) |
bc54da21 | 7914 | tsk->sched_class->task_move_group(tsk); |
b2b5ce02 | 7915 | else |
810b3817 | 7916 | #endif |
b2b5ce02 | 7917 | set_task_rq(tsk, task_cpu(tsk)); |
810b3817 | 7918 | |
0e1f3483 HS |
7919 | if (unlikely(running)) |
7920 | tsk->sched_class->set_curr_task(rq); | |
da0c1e65 | 7921 | if (queued) |
1de64443 | 7922 | enqueue_task(rq, tsk, ENQUEUE_RESTORE); |
29f59db3 | 7923 | |
0122ec5b | 7924 | task_rq_unlock(rq, tsk, &flags); |
29f59db3 | 7925 | } |
7c941438 | 7926 | #endif /* CONFIG_CGROUP_SCHED */ |
29f59db3 | 7927 | |
a790de99 PT |
7928 | #ifdef CONFIG_RT_GROUP_SCHED |
7929 | /* | |
7930 | * Ensure that the real time constraints are schedulable. | |
7931 | */ | |
7932 | static DEFINE_MUTEX(rt_constraints_mutex); | |
9f0c1e56 | 7933 | |
9a7e0b18 PZ |
7934 | /* Must be called with tasklist_lock held */ |
7935 | static inline int tg_has_rt_tasks(struct task_group *tg) | |
b40b2e8e | 7936 | { |
9a7e0b18 | 7937 | struct task_struct *g, *p; |
b40b2e8e | 7938 | |
1fe89e1b PZ |
7939 | /* |
7940 | * Autogroups do not have RT tasks; see autogroup_create(). | |
7941 | */ | |
7942 | if (task_group_is_autogroup(tg)) | |
7943 | return 0; | |
7944 | ||
5d07f420 | 7945 | for_each_process_thread(g, p) { |
8651c658 | 7946 | if (rt_task(p) && task_group(p) == tg) |
9a7e0b18 | 7947 | return 1; |
5d07f420 | 7948 | } |
b40b2e8e | 7949 | |
9a7e0b18 PZ |
7950 | return 0; |
7951 | } | |
b40b2e8e | 7952 | |
9a7e0b18 PZ |
7953 | struct rt_schedulable_data { |
7954 | struct task_group *tg; | |
7955 | u64 rt_period; | |
7956 | u64 rt_runtime; | |
7957 | }; | |
b40b2e8e | 7958 | |
a790de99 | 7959 | static int tg_rt_schedulable(struct task_group *tg, void *data) |
9a7e0b18 PZ |
7960 | { |
7961 | struct rt_schedulable_data *d = data; | |
7962 | struct task_group *child; | |
7963 | unsigned long total, sum = 0; | |
7964 | u64 period, runtime; | |
b40b2e8e | 7965 | |
9a7e0b18 PZ |
7966 | period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
7967 | runtime = tg->rt_bandwidth.rt_runtime; | |
b40b2e8e | 7968 | |
9a7e0b18 PZ |
7969 | if (tg == d->tg) { |
7970 | period = d->rt_period; | |
7971 | runtime = d->rt_runtime; | |
b40b2e8e | 7972 | } |
b40b2e8e | 7973 | |
4653f803 PZ |
7974 | /* |
7975 | * Cannot have more runtime than the period. | |
7976 | */ | |
7977 | if (runtime > period && runtime != RUNTIME_INF) | |
7978 | return -EINVAL; | |
6f505b16 | 7979 | |
4653f803 PZ |
7980 | /* |
7981 | * Ensure we don't starve existing RT tasks. | |
7982 | */ | |
9a7e0b18 PZ |
7983 | if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg)) |
7984 | return -EBUSY; | |
6f505b16 | 7985 | |
9a7e0b18 | 7986 | total = to_ratio(period, runtime); |
6f505b16 | 7987 | |
4653f803 PZ |
7988 | /* |
7989 | * Nobody can have more than the global setting allows. | |
7990 | */ | |
7991 | if (total > to_ratio(global_rt_period(), global_rt_runtime())) | |
7992 | return -EINVAL; | |
6f505b16 | 7993 | |
4653f803 PZ |
7994 | /* |
7995 | * The sum of our children's runtime should not exceed our own. | |
7996 | */ | |
9a7e0b18 PZ |
7997 | list_for_each_entry_rcu(child, &tg->children, siblings) { |
7998 | period = ktime_to_ns(child->rt_bandwidth.rt_period); | |
7999 | runtime = child->rt_bandwidth.rt_runtime; | |
6f505b16 | 8000 | |
9a7e0b18 PZ |
8001 | if (child == d->tg) { |
8002 | period = d->rt_period; | |
8003 | runtime = d->rt_runtime; | |
8004 | } | |
6f505b16 | 8005 | |
9a7e0b18 | 8006 | sum += to_ratio(period, runtime); |
9f0c1e56 | 8007 | } |
6f505b16 | 8008 | |
9a7e0b18 PZ |
8009 | if (sum > total) |
8010 | return -EINVAL; | |
8011 | ||
8012 | return 0; | |
6f505b16 PZ |
8013 | } |
8014 | ||
9a7e0b18 | 8015 | static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
521f1a24 | 8016 | { |
8277434e PT |
8017 | int ret; |
8018 | ||
9a7e0b18 PZ |
8019 | struct rt_schedulable_data data = { |
8020 | .tg = tg, | |
8021 | .rt_period = period, | |
8022 | .rt_runtime = runtime, | |
8023 | }; | |
8024 | ||
8277434e PT |
8025 | rcu_read_lock(); |
8026 | ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data); | |
8027 | rcu_read_unlock(); | |
8028 | ||
8029 | return ret; | |
521f1a24 DG |
8030 | } |
8031 | ||
ab84d31e | 8032 | static int tg_set_rt_bandwidth(struct task_group *tg, |
d0b27fa7 | 8033 | u64 rt_period, u64 rt_runtime) |
6f505b16 | 8034 | { |
ac086bc2 | 8035 | int i, err = 0; |
9f0c1e56 | 8036 | |
2636ed5f PZ |
8037 | /* |
8038 | * Disallowing the root group RT runtime is BAD, it would disallow the | |
8039 | * kernel creating (and or operating) RT threads. | |
8040 | */ | |
8041 | if (tg == &root_task_group && rt_runtime == 0) | |
8042 | return -EINVAL; | |
8043 | ||
8044 | /* No period doesn't make any sense. */ | |
8045 | if (rt_period == 0) | |
8046 | return -EINVAL; | |
8047 | ||
9f0c1e56 | 8048 | mutex_lock(&rt_constraints_mutex); |
521f1a24 | 8049 | read_lock(&tasklist_lock); |
9a7e0b18 PZ |
8050 | err = __rt_schedulable(tg, rt_period, rt_runtime); |
8051 | if (err) | |
9f0c1e56 | 8052 | goto unlock; |
ac086bc2 | 8053 | |
0986b11b | 8054 | raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
d0b27fa7 PZ |
8055 | tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
8056 | tg->rt_bandwidth.rt_runtime = rt_runtime; | |
ac086bc2 PZ |
8057 | |
8058 | for_each_possible_cpu(i) { | |
8059 | struct rt_rq *rt_rq = tg->rt_rq[i]; | |
8060 | ||
0986b11b | 8061 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8062 | rt_rq->rt_runtime = rt_runtime; |
0986b11b | 8063 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8064 | } |
0986b11b | 8065 | raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
49246274 | 8066 | unlock: |
521f1a24 | 8067 | read_unlock(&tasklist_lock); |
9f0c1e56 PZ |
8068 | mutex_unlock(&rt_constraints_mutex); |
8069 | ||
8070 | return err; | |
6f505b16 PZ |
8071 | } |
8072 | ||
25cc7da7 | 8073 | static int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
d0b27fa7 PZ |
8074 | { |
8075 | u64 rt_runtime, rt_period; | |
8076 | ||
8077 | rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
8078 | rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; | |
8079 | if (rt_runtime_us < 0) | |
8080 | rt_runtime = RUNTIME_INF; | |
8081 | ||
ab84d31e | 8082 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
8083 | } |
8084 | ||
25cc7da7 | 8085 | static long sched_group_rt_runtime(struct task_group *tg) |
9f0c1e56 PZ |
8086 | { |
8087 | u64 rt_runtime_us; | |
8088 | ||
d0b27fa7 | 8089 | if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
9f0c1e56 PZ |
8090 | return -1; |
8091 | ||
d0b27fa7 | 8092 | rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
9f0c1e56 PZ |
8093 | do_div(rt_runtime_us, NSEC_PER_USEC); |
8094 | return rt_runtime_us; | |
8095 | } | |
d0b27fa7 | 8096 | |
ce2f5fe4 | 8097 | static int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us) |
d0b27fa7 PZ |
8098 | { |
8099 | u64 rt_runtime, rt_period; | |
8100 | ||
ce2f5fe4 | 8101 | rt_period = rt_period_us * NSEC_PER_USEC; |
d0b27fa7 PZ |
8102 | rt_runtime = tg->rt_bandwidth.rt_runtime; |
8103 | ||
ab84d31e | 8104 | return tg_set_rt_bandwidth(tg, rt_period, rt_runtime); |
d0b27fa7 PZ |
8105 | } |
8106 | ||
25cc7da7 | 8107 | static long sched_group_rt_period(struct task_group *tg) |
d0b27fa7 PZ |
8108 | { |
8109 | u64 rt_period_us; | |
8110 | ||
8111 | rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); | |
8112 | do_div(rt_period_us, NSEC_PER_USEC); | |
8113 | return rt_period_us; | |
8114 | } | |
332ac17e | 8115 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 8116 | |
332ac17e | 8117 | #ifdef CONFIG_RT_GROUP_SCHED |
d0b27fa7 PZ |
8118 | static int sched_rt_global_constraints(void) |
8119 | { | |
8120 | int ret = 0; | |
8121 | ||
8122 | mutex_lock(&rt_constraints_mutex); | |
9a7e0b18 | 8123 | read_lock(&tasklist_lock); |
4653f803 | 8124 | ret = __rt_schedulable(NULL, 0, 0); |
9a7e0b18 | 8125 | read_unlock(&tasklist_lock); |
d0b27fa7 PZ |
8126 | mutex_unlock(&rt_constraints_mutex); |
8127 | ||
8128 | return ret; | |
8129 | } | |
54e99124 | 8130 | |
25cc7da7 | 8131 | static int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk) |
54e99124 DG |
8132 | { |
8133 | /* Don't accept realtime tasks when there is no way for them to run */ | |
8134 | if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0) | |
8135 | return 0; | |
8136 | ||
8137 | return 1; | |
8138 | } | |
8139 | ||
6d6bc0ad | 8140 | #else /* !CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 PZ |
8141 | static int sched_rt_global_constraints(void) |
8142 | { | |
ac086bc2 | 8143 | unsigned long flags; |
332ac17e | 8144 | int i, ret = 0; |
ec5d4989 | 8145 | |
0986b11b | 8146 | raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 PZ |
8147 | for_each_possible_cpu(i) { |
8148 | struct rt_rq *rt_rq = &cpu_rq(i)->rt; | |
8149 | ||
0986b11b | 8150 | raw_spin_lock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8151 | rt_rq->rt_runtime = global_rt_runtime(); |
0986b11b | 8152 | raw_spin_unlock(&rt_rq->rt_runtime_lock); |
ac086bc2 | 8153 | } |
0986b11b | 8154 | raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
ac086bc2 | 8155 | |
332ac17e | 8156 | return ret; |
d0b27fa7 | 8157 | } |
6d6bc0ad | 8158 | #endif /* CONFIG_RT_GROUP_SCHED */ |
d0b27fa7 | 8159 | |
a1963b81 | 8160 | static int sched_dl_global_validate(void) |
332ac17e | 8161 | { |
1724813d PZ |
8162 | u64 runtime = global_rt_runtime(); |
8163 | u64 period = global_rt_period(); | |
332ac17e | 8164 | u64 new_bw = to_ratio(period, runtime); |
f10e00f4 | 8165 | struct dl_bw *dl_b; |
1724813d | 8166 | int cpu, ret = 0; |
49516342 | 8167 | unsigned long flags; |
332ac17e DF |
8168 | |
8169 | /* | |
8170 | * Here we want to check the bandwidth not being set to some | |
8171 | * value smaller than the currently allocated bandwidth in | |
8172 | * any of the root_domains. | |
8173 | * | |
8174 | * FIXME: Cycling on all the CPUs is overdoing, but simpler than | |
8175 | * cycling on root_domains... Discussion on different/better | |
8176 | * solutions is welcome! | |
8177 | */ | |
1724813d | 8178 | for_each_possible_cpu(cpu) { |
f10e00f4 KT |
8179 | rcu_read_lock_sched(); |
8180 | dl_b = dl_bw_of(cpu); | |
332ac17e | 8181 | |
49516342 | 8182 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
1724813d PZ |
8183 | if (new_bw < dl_b->total_bw) |
8184 | ret = -EBUSY; | |
49516342 | 8185 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
1724813d | 8186 | |
f10e00f4 KT |
8187 | rcu_read_unlock_sched(); |
8188 | ||
1724813d PZ |
8189 | if (ret) |
8190 | break; | |
332ac17e DF |
8191 | } |
8192 | ||
1724813d | 8193 | return ret; |
332ac17e DF |
8194 | } |
8195 | ||
1724813d | 8196 | static void sched_dl_do_global(void) |
ce0dbbbb | 8197 | { |
1724813d | 8198 | u64 new_bw = -1; |
f10e00f4 | 8199 | struct dl_bw *dl_b; |
1724813d | 8200 | int cpu; |
49516342 | 8201 | unsigned long flags; |
ce0dbbbb | 8202 | |
1724813d PZ |
8203 | def_dl_bandwidth.dl_period = global_rt_period(); |
8204 | def_dl_bandwidth.dl_runtime = global_rt_runtime(); | |
8205 | ||
8206 | if (global_rt_runtime() != RUNTIME_INF) | |
8207 | new_bw = to_ratio(global_rt_period(), global_rt_runtime()); | |
8208 | ||
8209 | /* | |
8210 | * FIXME: As above... | |
8211 | */ | |
8212 | for_each_possible_cpu(cpu) { | |
f10e00f4 KT |
8213 | rcu_read_lock_sched(); |
8214 | dl_b = dl_bw_of(cpu); | |
1724813d | 8215 | |
49516342 | 8216 | raw_spin_lock_irqsave(&dl_b->lock, flags); |
1724813d | 8217 | dl_b->bw = new_bw; |
49516342 | 8218 | raw_spin_unlock_irqrestore(&dl_b->lock, flags); |
f10e00f4 KT |
8219 | |
8220 | rcu_read_unlock_sched(); | |
ce0dbbbb | 8221 | } |
1724813d PZ |
8222 | } |
8223 | ||
8224 | static int sched_rt_global_validate(void) | |
8225 | { | |
8226 | if (sysctl_sched_rt_period <= 0) | |
8227 | return -EINVAL; | |
8228 | ||
e9e7cb38 JL |
8229 | if ((sysctl_sched_rt_runtime != RUNTIME_INF) && |
8230 | (sysctl_sched_rt_runtime > sysctl_sched_rt_period)) | |
1724813d PZ |
8231 | return -EINVAL; |
8232 | ||
8233 | return 0; | |
8234 | } | |
8235 | ||
8236 | static void sched_rt_do_global(void) | |
8237 | { | |
8238 | def_rt_bandwidth.rt_runtime = global_rt_runtime(); | |
8239 | def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period()); | |
ce0dbbbb CW |
8240 | } |
8241 | ||
d0b27fa7 | 8242 | int sched_rt_handler(struct ctl_table *table, int write, |
8d65af78 | 8243 | void __user *buffer, size_t *lenp, |
d0b27fa7 PZ |
8244 | loff_t *ppos) |
8245 | { | |
d0b27fa7 PZ |
8246 | int old_period, old_runtime; |
8247 | static DEFINE_MUTEX(mutex); | |
1724813d | 8248 | int ret; |
d0b27fa7 PZ |
8249 | |
8250 | mutex_lock(&mutex); | |
8251 | old_period = sysctl_sched_rt_period; | |
8252 | old_runtime = sysctl_sched_rt_runtime; | |
8253 | ||
8d65af78 | 8254 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
d0b27fa7 PZ |
8255 | |
8256 | if (!ret && write) { | |
1724813d PZ |
8257 | ret = sched_rt_global_validate(); |
8258 | if (ret) | |
8259 | goto undo; | |
8260 | ||
a1963b81 | 8261 | ret = sched_dl_global_validate(); |
1724813d PZ |
8262 | if (ret) |
8263 | goto undo; | |
8264 | ||
a1963b81 | 8265 | ret = sched_rt_global_constraints(); |
1724813d PZ |
8266 | if (ret) |
8267 | goto undo; | |
8268 | ||
8269 | sched_rt_do_global(); | |
8270 | sched_dl_do_global(); | |
8271 | } | |
8272 | if (0) { | |
8273 | undo: | |
8274 | sysctl_sched_rt_period = old_period; | |
8275 | sysctl_sched_rt_runtime = old_runtime; | |
d0b27fa7 PZ |
8276 | } |
8277 | mutex_unlock(&mutex); | |
8278 | ||
8279 | return ret; | |
8280 | } | |
68318b8e | 8281 | |
1724813d | 8282 | int sched_rr_handler(struct ctl_table *table, int write, |
332ac17e DF |
8283 | void __user *buffer, size_t *lenp, |
8284 | loff_t *ppos) | |
8285 | { | |
8286 | int ret; | |
332ac17e | 8287 | static DEFINE_MUTEX(mutex); |
332ac17e DF |
8288 | |
8289 | mutex_lock(&mutex); | |
332ac17e | 8290 | ret = proc_dointvec(table, write, buffer, lenp, ppos); |
1724813d PZ |
8291 | /* make sure that internally we keep jiffies */ |
8292 | /* also, writing zero resets timeslice to default */ | |
332ac17e | 8293 | if (!ret && write) { |
1724813d PZ |
8294 | sched_rr_timeslice = sched_rr_timeslice <= 0 ? |
8295 | RR_TIMESLICE : msecs_to_jiffies(sched_rr_timeslice); | |
332ac17e DF |
8296 | } |
8297 | mutex_unlock(&mutex); | |
332ac17e DF |
8298 | return ret; |
8299 | } | |
8300 | ||
052f1dc7 | 8301 | #ifdef CONFIG_CGROUP_SCHED |
68318b8e | 8302 | |
a7c6d554 | 8303 | static inline struct task_group *css_tg(struct cgroup_subsys_state *css) |
68318b8e | 8304 | { |
a7c6d554 | 8305 | return css ? container_of(css, struct task_group, css) : NULL; |
68318b8e SV |
8306 | } |
8307 | ||
eb95419b TH |
8308 | static struct cgroup_subsys_state * |
8309 | cpu_cgroup_css_alloc(struct cgroup_subsys_state *parent_css) | |
68318b8e | 8310 | { |
eb95419b TH |
8311 | struct task_group *parent = css_tg(parent_css); |
8312 | struct task_group *tg; | |
68318b8e | 8313 | |
eb95419b | 8314 | if (!parent) { |
68318b8e | 8315 | /* This is early initialization for the top cgroup */ |
07e06b01 | 8316 | return &root_task_group.css; |
68318b8e SV |
8317 | } |
8318 | ||
ec7dc8ac | 8319 | tg = sched_create_group(parent); |
68318b8e SV |
8320 | if (IS_ERR(tg)) |
8321 | return ERR_PTR(-ENOMEM); | |
8322 | ||
68318b8e SV |
8323 | return &tg->css; |
8324 | } | |
8325 | ||
eb95419b | 8326 | static int cpu_cgroup_css_online(struct cgroup_subsys_state *css) |
ace783b9 | 8327 | { |
eb95419b | 8328 | struct task_group *tg = css_tg(css); |
5c9d535b | 8329 | struct task_group *parent = css_tg(css->parent); |
ace783b9 | 8330 | |
63876986 TH |
8331 | if (parent) |
8332 | sched_online_group(tg, parent); | |
ace783b9 LZ |
8333 | return 0; |
8334 | } | |
8335 | ||
eb95419b | 8336 | static void cpu_cgroup_css_free(struct cgroup_subsys_state *css) |
68318b8e | 8337 | { |
eb95419b | 8338 | struct task_group *tg = css_tg(css); |
68318b8e SV |
8339 | |
8340 | sched_destroy_group(tg); | |
8341 | } | |
8342 | ||
eb95419b | 8343 | static void cpu_cgroup_css_offline(struct cgroup_subsys_state *css) |
ace783b9 | 8344 | { |
eb95419b | 8345 | struct task_group *tg = css_tg(css); |
ace783b9 LZ |
8346 | |
8347 | sched_offline_group(tg); | |
8348 | } | |
8349 | ||
b53202e6 | 8350 | static void cpu_cgroup_fork(struct task_struct *task) |
eeb61e53 KT |
8351 | { |
8352 | sched_move_task(task); | |
8353 | } | |
8354 | ||
1f7dd3e5 | 8355 | static int cpu_cgroup_can_attach(struct cgroup_taskset *tset) |
68318b8e | 8356 | { |
bb9d97b6 | 8357 | struct task_struct *task; |
1f7dd3e5 | 8358 | struct cgroup_subsys_state *css; |
bb9d97b6 | 8359 | |
1f7dd3e5 | 8360 | cgroup_taskset_for_each(task, css, tset) { |
b68aa230 | 8361 | #ifdef CONFIG_RT_GROUP_SCHED |
eb95419b | 8362 | if (!sched_rt_can_attach(css_tg(css), task)) |
bb9d97b6 | 8363 | return -EINVAL; |
b68aa230 | 8364 | #else |
bb9d97b6 TH |
8365 | /* We don't support RT-tasks being in separate groups */ |
8366 | if (task->sched_class != &fair_sched_class) | |
8367 | return -EINVAL; | |
b68aa230 | 8368 | #endif |
bb9d97b6 | 8369 | } |
be367d09 BB |
8370 | return 0; |
8371 | } | |
68318b8e | 8372 | |
1f7dd3e5 | 8373 | static void cpu_cgroup_attach(struct cgroup_taskset *tset) |
68318b8e | 8374 | { |
bb9d97b6 | 8375 | struct task_struct *task; |
1f7dd3e5 | 8376 | struct cgroup_subsys_state *css; |
bb9d97b6 | 8377 | |
1f7dd3e5 | 8378 | cgroup_taskset_for_each(task, css, tset) |
bb9d97b6 | 8379 | sched_move_task(task); |
68318b8e SV |
8380 | } |
8381 | ||
052f1dc7 | 8382 | #ifdef CONFIG_FAIR_GROUP_SCHED |
182446d0 TH |
8383 | static int cpu_shares_write_u64(struct cgroup_subsys_state *css, |
8384 | struct cftype *cftype, u64 shareval) | |
68318b8e | 8385 | { |
182446d0 | 8386 | return sched_group_set_shares(css_tg(css), scale_load(shareval)); |
68318b8e SV |
8387 | } |
8388 | ||
182446d0 TH |
8389 | static u64 cpu_shares_read_u64(struct cgroup_subsys_state *css, |
8390 | struct cftype *cft) | |
68318b8e | 8391 | { |
182446d0 | 8392 | struct task_group *tg = css_tg(css); |
68318b8e | 8393 | |
c8b28116 | 8394 | return (u64) scale_load_down(tg->shares); |
68318b8e | 8395 | } |
ab84d31e PT |
8396 | |
8397 | #ifdef CONFIG_CFS_BANDWIDTH | |
a790de99 PT |
8398 | static DEFINE_MUTEX(cfs_constraints_mutex); |
8399 | ||
ab84d31e PT |
8400 | const u64 max_cfs_quota_period = 1 * NSEC_PER_SEC; /* 1s */ |
8401 | const u64 min_cfs_quota_period = 1 * NSEC_PER_MSEC; /* 1ms */ | |
8402 | ||
a790de99 PT |
8403 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 runtime); |
8404 | ||
ab84d31e PT |
8405 | static int tg_set_cfs_bandwidth(struct task_group *tg, u64 period, u64 quota) |
8406 | { | |
56f570e5 | 8407 | int i, ret = 0, runtime_enabled, runtime_was_enabled; |
029632fb | 8408 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
ab84d31e PT |
8409 | |
8410 | if (tg == &root_task_group) | |
8411 | return -EINVAL; | |
8412 | ||
8413 | /* | |
8414 | * Ensure we have at some amount of bandwidth every period. This is | |
8415 | * to prevent reaching a state of large arrears when throttled via | |
8416 | * entity_tick() resulting in prolonged exit starvation. | |
8417 | */ | |
8418 | if (quota < min_cfs_quota_period || period < min_cfs_quota_period) | |
8419 | return -EINVAL; | |
8420 | ||
8421 | /* | |
8422 | * Likewise, bound things on the otherside by preventing insane quota | |
8423 | * periods. This also allows us to normalize in computing quota | |
8424 | * feasibility. | |
8425 | */ | |
8426 | if (period > max_cfs_quota_period) | |
8427 | return -EINVAL; | |
8428 | ||
0e59bdae KT |
8429 | /* |
8430 | * Prevent race between setting of cfs_rq->runtime_enabled and | |
8431 | * unthrottle_offline_cfs_rqs(). | |
8432 | */ | |
8433 | get_online_cpus(); | |
a790de99 PT |
8434 | mutex_lock(&cfs_constraints_mutex); |
8435 | ret = __cfs_schedulable(tg, period, quota); | |
8436 | if (ret) | |
8437 | goto out_unlock; | |
8438 | ||
58088ad0 | 8439 | runtime_enabled = quota != RUNTIME_INF; |
56f570e5 | 8440 | runtime_was_enabled = cfs_b->quota != RUNTIME_INF; |
1ee14e6c BS |
8441 | /* |
8442 | * If we need to toggle cfs_bandwidth_used, off->on must occur | |
8443 | * before making related changes, and on->off must occur afterwards | |
8444 | */ | |
8445 | if (runtime_enabled && !runtime_was_enabled) | |
8446 | cfs_bandwidth_usage_inc(); | |
ab84d31e PT |
8447 | raw_spin_lock_irq(&cfs_b->lock); |
8448 | cfs_b->period = ns_to_ktime(period); | |
8449 | cfs_b->quota = quota; | |
58088ad0 | 8450 | |
a9cf55b2 | 8451 | __refill_cfs_bandwidth_runtime(cfs_b); |
58088ad0 | 8452 | /* restart the period timer (if active) to handle new period expiry */ |
77a4d1a1 PZ |
8453 | if (runtime_enabled) |
8454 | start_cfs_bandwidth(cfs_b); | |
ab84d31e PT |
8455 | raw_spin_unlock_irq(&cfs_b->lock); |
8456 | ||
0e59bdae | 8457 | for_each_online_cpu(i) { |
ab84d31e | 8458 | struct cfs_rq *cfs_rq = tg->cfs_rq[i]; |
029632fb | 8459 | struct rq *rq = cfs_rq->rq; |
ab84d31e PT |
8460 | |
8461 | raw_spin_lock_irq(&rq->lock); | |
58088ad0 | 8462 | cfs_rq->runtime_enabled = runtime_enabled; |
ab84d31e | 8463 | cfs_rq->runtime_remaining = 0; |
671fd9da | 8464 | |
029632fb | 8465 | if (cfs_rq->throttled) |
671fd9da | 8466 | unthrottle_cfs_rq(cfs_rq); |
ab84d31e PT |
8467 | raw_spin_unlock_irq(&rq->lock); |
8468 | } | |
1ee14e6c BS |
8469 | if (runtime_was_enabled && !runtime_enabled) |
8470 | cfs_bandwidth_usage_dec(); | |
a790de99 PT |
8471 | out_unlock: |
8472 | mutex_unlock(&cfs_constraints_mutex); | |
0e59bdae | 8473 | put_online_cpus(); |
ab84d31e | 8474 | |
a790de99 | 8475 | return ret; |
ab84d31e PT |
8476 | } |
8477 | ||
8478 | int tg_set_cfs_quota(struct task_group *tg, long cfs_quota_us) | |
8479 | { | |
8480 | u64 quota, period; | |
8481 | ||
029632fb | 8482 | period = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
8483 | if (cfs_quota_us < 0) |
8484 | quota = RUNTIME_INF; | |
8485 | else | |
8486 | quota = (u64)cfs_quota_us * NSEC_PER_USEC; | |
8487 | ||
8488 | return tg_set_cfs_bandwidth(tg, period, quota); | |
8489 | } | |
8490 | ||
8491 | long tg_get_cfs_quota(struct task_group *tg) | |
8492 | { | |
8493 | u64 quota_us; | |
8494 | ||
029632fb | 8495 | if (tg->cfs_bandwidth.quota == RUNTIME_INF) |
ab84d31e PT |
8496 | return -1; |
8497 | ||
029632fb | 8498 | quota_us = tg->cfs_bandwidth.quota; |
ab84d31e PT |
8499 | do_div(quota_us, NSEC_PER_USEC); |
8500 | ||
8501 | return quota_us; | |
8502 | } | |
8503 | ||
8504 | int tg_set_cfs_period(struct task_group *tg, long cfs_period_us) | |
8505 | { | |
8506 | u64 quota, period; | |
8507 | ||
8508 | period = (u64)cfs_period_us * NSEC_PER_USEC; | |
029632fb | 8509 | quota = tg->cfs_bandwidth.quota; |
ab84d31e | 8510 | |
ab84d31e PT |
8511 | return tg_set_cfs_bandwidth(tg, period, quota); |
8512 | } | |
8513 | ||
8514 | long tg_get_cfs_period(struct task_group *tg) | |
8515 | { | |
8516 | u64 cfs_period_us; | |
8517 | ||
029632fb | 8518 | cfs_period_us = ktime_to_ns(tg->cfs_bandwidth.period); |
ab84d31e PT |
8519 | do_div(cfs_period_us, NSEC_PER_USEC); |
8520 | ||
8521 | return cfs_period_us; | |
8522 | } | |
8523 | ||
182446d0 TH |
8524 | static s64 cpu_cfs_quota_read_s64(struct cgroup_subsys_state *css, |
8525 | struct cftype *cft) | |
ab84d31e | 8526 | { |
182446d0 | 8527 | return tg_get_cfs_quota(css_tg(css)); |
ab84d31e PT |
8528 | } |
8529 | ||
182446d0 TH |
8530 | static int cpu_cfs_quota_write_s64(struct cgroup_subsys_state *css, |
8531 | struct cftype *cftype, s64 cfs_quota_us) | |
ab84d31e | 8532 | { |
182446d0 | 8533 | return tg_set_cfs_quota(css_tg(css), cfs_quota_us); |
ab84d31e PT |
8534 | } |
8535 | ||
182446d0 TH |
8536 | static u64 cpu_cfs_period_read_u64(struct cgroup_subsys_state *css, |
8537 | struct cftype *cft) | |
ab84d31e | 8538 | { |
182446d0 | 8539 | return tg_get_cfs_period(css_tg(css)); |
ab84d31e PT |
8540 | } |
8541 | ||
182446d0 TH |
8542 | static int cpu_cfs_period_write_u64(struct cgroup_subsys_state *css, |
8543 | struct cftype *cftype, u64 cfs_period_us) | |
ab84d31e | 8544 | { |
182446d0 | 8545 | return tg_set_cfs_period(css_tg(css), cfs_period_us); |
ab84d31e PT |
8546 | } |
8547 | ||
a790de99 PT |
8548 | struct cfs_schedulable_data { |
8549 | struct task_group *tg; | |
8550 | u64 period, quota; | |
8551 | }; | |
8552 | ||
8553 | /* | |
8554 | * normalize group quota/period to be quota/max_period | |
8555 | * note: units are usecs | |
8556 | */ | |
8557 | static u64 normalize_cfs_quota(struct task_group *tg, | |
8558 | struct cfs_schedulable_data *d) | |
8559 | { | |
8560 | u64 quota, period; | |
8561 | ||
8562 | if (tg == d->tg) { | |
8563 | period = d->period; | |
8564 | quota = d->quota; | |
8565 | } else { | |
8566 | period = tg_get_cfs_period(tg); | |
8567 | quota = tg_get_cfs_quota(tg); | |
8568 | } | |
8569 | ||
8570 | /* note: these should typically be equivalent */ | |
8571 | if (quota == RUNTIME_INF || quota == -1) | |
8572 | return RUNTIME_INF; | |
8573 | ||
8574 | return to_ratio(period, quota); | |
8575 | } | |
8576 | ||
8577 | static int tg_cfs_schedulable_down(struct task_group *tg, void *data) | |
8578 | { | |
8579 | struct cfs_schedulable_data *d = data; | |
029632fb | 8580 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
a790de99 PT |
8581 | s64 quota = 0, parent_quota = -1; |
8582 | ||
8583 | if (!tg->parent) { | |
8584 | quota = RUNTIME_INF; | |
8585 | } else { | |
029632fb | 8586 | struct cfs_bandwidth *parent_b = &tg->parent->cfs_bandwidth; |
a790de99 PT |
8587 | |
8588 | quota = normalize_cfs_quota(tg, d); | |
9c58c79a | 8589 | parent_quota = parent_b->hierarchical_quota; |
a790de99 PT |
8590 | |
8591 | /* | |
8592 | * ensure max(child_quota) <= parent_quota, inherit when no | |
8593 | * limit is set | |
8594 | */ | |
8595 | if (quota == RUNTIME_INF) | |
8596 | quota = parent_quota; | |
8597 | else if (parent_quota != RUNTIME_INF && quota > parent_quota) | |
8598 | return -EINVAL; | |
8599 | } | |
9c58c79a | 8600 | cfs_b->hierarchical_quota = quota; |
a790de99 PT |
8601 | |
8602 | return 0; | |
8603 | } | |
8604 | ||
8605 | static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) | |
8606 | { | |
8277434e | 8607 | int ret; |
a790de99 PT |
8608 | struct cfs_schedulable_data data = { |
8609 | .tg = tg, | |
8610 | .period = period, | |
8611 | .quota = quota, | |
8612 | }; | |
8613 | ||
8614 | if (quota != RUNTIME_INF) { | |
8615 | do_div(data.period, NSEC_PER_USEC); | |
8616 | do_div(data.quota, NSEC_PER_USEC); | |
8617 | } | |
8618 | ||
8277434e PT |
8619 | rcu_read_lock(); |
8620 | ret = walk_tg_tree(tg_cfs_schedulable_down, tg_nop, &data); | |
8621 | rcu_read_unlock(); | |
8622 | ||
8623 | return ret; | |
a790de99 | 8624 | } |
e8da1b18 | 8625 | |
2da8ca82 | 8626 | static int cpu_stats_show(struct seq_file *sf, void *v) |
e8da1b18 | 8627 | { |
2da8ca82 | 8628 | struct task_group *tg = css_tg(seq_css(sf)); |
029632fb | 8629 | struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; |
e8da1b18 | 8630 | |
44ffc75b TH |
8631 | seq_printf(sf, "nr_periods %d\n", cfs_b->nr_periods); |
8632 | seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); | |
8633 | seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); | |
e8da1b18 NR |
8634 | |
8635 | return 0; | |
8636 | } | |
ab84d31e | 8637 | #endif /* CONFIG_CFS_BANDWIDTH */ |
6d6bc0ad | 8638 | #endif /* CONFIG_FAIR_GROUP_SCHED */ |
68318b8e | 8639 | |
052f1dc7 | 8640 | #ifdef CONFIG_RT_GROUP_SCHED |
182446d0 TH |
8641 | static int cpu_rt_runtime_write(struct cgroup_subsys_state *css, |
8642 | struct cftype *cft, s64 val) | |
6f505b16 | 8643 | { |
182446d0 | 8644 | return sched_group_set_rt_runtime(css_tg(css), val); |
6f505b16 PZ |
8645 | } |
8646 | ||
182446d0 TH |
8647 | static s64 cpu_rt_runtime_read(struct cgroup_subsys_state *css, |
8648 | struct cftype *cft) | |
6f505b16 | 8649 | { |
182446d0 | 8650 | return sched_group_rt_runtime(css_tg(css)); |
6f505b16 | 8651 | } |
d0b27fa7 | 8652 | |
182446d0 TH |
8653 | static int cpu_rt_period_write_uint(struct cgroup_subsys_state *css, |
8654 | struct cftype *cftype, u64 rt_period_us) | |
d0b27fa7 | 8655 | { |
182446d0 | 8656 | return sched_group_set_rt_period(css_tg(css), rt_period_us); |
d0b27fa7 PZ |
8657 | } |
8658 | ||
182446d0 TH |
8659 | static u64 cpu_rt_period_read_uint(struct cgroup_subsys_state *css, |
8660 | struct cftype *cft) | |
d0b27fa7 | 8661 | { |
182446d0 | 8662 | return sched_group_rt_period(css_tg(css)); |
d0b27fa7 | 8663 | } |
6d6bc0ad | 8664 | #endif /* CONFIG_RT_GROUP_SCHED */ |
6f505b16 | 8665 | |
fe5c7cc2 | 8666 | static struct cftype cpu_files[] = { |
052f1dc7 | 8667 | #ifdef CONFIG_FAIR_GROUP_SCHED |
fe5c7cc2 PM |
8668 | { |
8669 | .name = "shares", | |
f4c753b7 PM |
8670 | .read_u64 = cpu_shares_read_u64, |
8671 | .write_u64 = cpu_shares_write_u64, | |
fe5c7cc2 | 8672 | }, |
052f1dc7 | 8673 | #endif |
ab84d31e PT |
8674 | #ifdef CONFIG_CFS_BANDWIDTH |
8675 | { | |
8676 | .name = "cfs_quota_us", | |
8677 | .read_s64 = cpu_cfs_quota_read_s64, | |
8678 | .write_s64 = cpu_cfs_quota_write_s64, | |
8679 | }, | |
8680 | { | |
8681 | .name = "cfs_period_us", | |
8682 | .read_u64 = cpu_cfs_period_read_u64, | |
8683 | .write_u64 = cpu_cfs_period_write_u64, | |
8684 | }, | |
e8da1b18 NR |
8685 | { |
8686 | .name = "stat", | |
2da8ca82 | 8687 | .seq_show = cpu_stats_show, |
e8da1b18 | 8688 | }, |
ab84d31e | 8689 | #endif |
052f1dc7 | 8690 | #ifdef CONFIG_RT_GROUP_SCHED |
6f505b16 | 8691 | { |
9f0c1e56 | 8692 | .name = "rt_runtime_us", |
06ecb27c PM |
8693 | .read_s64 = cpu_rt_runtime_read, |
8694 | .write_s64 = cpu_rt_runtime_write, | |
6f505b16 | 8695 | }, |
d0b27fa7 PZ |
8696 | { |
8697 | .name = "rt_period_us", | |
f4c753b7 PM |
8698 | .read_u64 = cpu_rt_period_read_uint, |
8699 | .write_u64 = cpu_rt_period_write_uint, | |
d0b27fa7 | 8700 | }, |
052f1dc7 | 8701 | #endif |
4baf6e33 | 8702 | { } /* terminate */ |
68318b8e SV |
8703 | }; |
8704 | ||
073219e9 | 8705 | struct cgroup_subsys cpu_cgrp_subsys = { |
92fb9748 TH |
8706 | .css_alloc = cpu_cgroup_css_alloc, |
8707 | .css_free = cpu_cgroup_css_free, | |
ace783b9 LZ |
8708 | .css_online = cpu_cgroup_css_online, |
8709 | .css_offline = cpu_cgroup_css_offline, | |
eeb61e53 | 8710 | .fork = cpu_cgroup_fork, |
bb9d97b6 TH |
8711 | .can_attach = cpu_cgroup_can_attach, |
8712 | .attach = cpu_cgroup_attach, | |
5577964e | 8713 | .legacy_cftypes = cpu_files, |
68318b8e SV |
8714 | .early_init = 1, |
8715 | }; | |
8716 | ||
052f1dc7 | 8717 | #endif /* CONFIG_CGROUP_SCHED */ |
d842de87 | 8718 | |
b637a328 PM |
8719 | void dump_cpu_task(int cpu) |
8720 | { | |
8721 | pr_info("Task dump for CPU %d:\n", cpu); | |
8722 | sched_show_task(cpu_curr(cpu)); | |
8723 | } | |
ed82b8a1 AK |
8724 | |
8725 | /* | |
8726 | * Nice levels are multiplicative, with a gentle 10% change for every | |
8727 | * nice level changed. I.e. when a CPU-bound task goes from nice 0 to | |
8728 | * nice 1, it will get ~10% less CPU time than another CPU-bound task | |
8729 | * that remained on nice 0. | |
8730 | * | |
8731 | * The "10% effect" is relative and cumulative: from _any_ nice level, | |
8732 | * if you go up 1 level, it's -10% CPU usage, if you go down 1 level | |
8733 | * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. | |
8734 | * If a task goes up by ~10% and another task goes down by ~10% then | |
8735 | * the relative distance between them is ~25%.) | |
8736 | */ | |
8737 | const int sched_prio_to_weight[40] = { | |
8738 | /* -20 */ 88761, 71755, 56483, 46273, 36291, | |
8739 | /* -15 */ 29154, 23254, 18705, 14949, 11916, | |
8740 | /* -10 */ 9548, 7620, 6100, 4904, 3906, | |
8741 | /* -5 */ 3121, 2501, 1991, 1586, 1277, | |
8742 | /* 0 */ 1024, 820, 655, 526, 423, | |
8743 | /* 5 */ 335, 272, 215, 172, 137, | |
8744 | /* 10 */ 110, 87, 70, 56, 45, | |
8745 | /* 15 */ 36, 29, 23, 18, 15, | |
8746 | }; | |
8747 | ||
8748 | /* | |
8749 | * Inverse (2^32/x) values of the sched_prio_to_weight[] array, precalculated. | |
8750 | * | |
8751 | * In cases where the weight does not change often, we can use the | |
8752 | * precalculated inverse to speed up arithmetics by turning divisions | |
8753 | * into multiplications: | |
8754 | */ | |
8755 | const u32 sched_prio_to_wmult[40] = { | |
8756 | /* -20 */ 48388, 59856, 76040, 92818, 118348, | |
8757 | /* -15 */ 147320, 184698, 229616, 287308, 360437, | |
8758 | /* -10 */ 449829, 563644, 704093, 875809, 1099582, | |
8759 | /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, | |
8760 | /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, | |
8761 | /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, | |
8762 | /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, | |
8763 | /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, | |
8764 | }; |