ARM: 7709/1: mcpm: Add explicit AFLAGS to support v6/v7 multiplatform kernels
[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / sched / cputime.c
1 #include <linux/export.h>
2 #include <linux/sched.h>
3 #include <linux/tsacct_kern.h>
4 #include <linux/kernel_stat.h>
5 #include <linux/static_key.h>
6 #include <linux/context_tracking.h>
7 #include "sched.h"
8
9
10 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
11
12 /*
13 * There are no locks covering percpu hardirq/softirq time.
14 * They are only modified in vtime_account, on corresponding CPU
15 * with interrupts disabled. So, writes are safe.
16 * They are read and saved off onto struct rq in update_rq_clock().
17 * This may result in other CPU reading this CPU's irq time and can
18 * race with irq/vtime_account on this CPU. We would either get old
19 * or new value with a side effect of accounting a slice of irq time to wrong
20 * task when irq is in progress while we read rq->clock. That is a worthy
21 * compromise in place of having locks on each irq in account_system_time.
22 */
23 DEFINE_PER_CPU(u64, cpu_hardirq_time);
24 DEFINE_PER_CPU(u64, cpu_softirq_time);
25
26 static DEFINE_PER_CPU(u64, irq_start_time);
27 static int sched_clock_irqtime;
28
29 void enable_sched_clock_irqtime(void)
30 {
31 sched_clock_irqtime = 1;
32 }
33
34 void disable_sched_clock_irqtime(void)
35 {
36 sched_clock_irqtime = 0;
37 }
38
39 #ifndef CONFIG_64BIT
40 DEFINE_PER_CPU(seqcount_t, irq_time_seq);
41 #endif /* CONFIG_64BIT */
42
43 /*
44 * Called before incrementing preempt_count on {soft,}irq_enter
45 * and before decrementing preempt_count on {soft,}irq_exit.
46 */
47 void irqtime_account_irq(struct task_struct *curr)
48 {
49 unsigned long flags;
50 s64 delta;
51 int cpu;
52
53 if (!sched_clock_irqtime)
54 return;
55
56 local_irq_save(flags);
57
58 cpu = smp_processor_id();
59 delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time);
60 __this_cpu_add(irq_start_time, delta);
61
62 irq_time_write_begin();
63 /*
64 * We do not account for softirq time from ksoftirqd here.
65 * We want to continue accounting softirq time to ksoftirqd thread
66 * in that case, so as not to confuse scheduler with a special task
67 * that do not consume any time, but still wants to run.
68 */
69 if (hardirq_count())
70 __this_cpu_add(cpu_hardirq_time, delta);
71 else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
72 __this_cpu_add(cpu_softirq_time, delta);
73
74 irq_time_write_end();
75 local_irq_restore(flags);
76 }
77 EXPORT_SYMBOL_GPL(irqtime_account_irq);
78
79 static int irqtime_account_hi_update(void)
80 {
81 u64 *cpustat = kcpustat_this_cpu->cpustat;
82 unsigned long flags;
83 u64 latest_ns;
84 int ret = 0;
85
86 local_irq_save(flags);
87 latest_ns = this_cpu_read(cpu_hardirq_time);
88 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ])
89 ret = 1;
90 local_irq_restore(flags);
91 return ret;
92 }
93
94 static int irqtime_account_si_update(void)
95 {
96 u64 *cpustat = kcpustat_this_cpu->cpustat;
97 unsigned long flags;
98 u64 latest_ns;
99 int ret = 0;
100
101 local_irq_save(flags);
102 latest_ns = this_cpu_read(cpu_softirq_time);
103 if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ])
104 ret = 1;
105 local_irq_restore(flags);
106 return ret;
107 }
108
109 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
110
111 #define sched_clock_irqtime (0)
112
113 #endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
114
115 static inline void task_group_account_field(struct task_struct *p, int index,
116 u64 tmp)
117 {
118 #ifdef CONFIG_CGROUP_CPUACCT
119 struct kernel_cpustat *kcpustat;
120 struct cpuacct *ca;
121 #endif
122 /*
123 * Since all updates are sure to touch the root cgroup, we
124 * get ourselves ahead and touch it first. If the root cgroup
125 * is the only cgroup, then nothing else should be necessary.
126 *
127 */
128 __get_cpu_var(kernel_cpustat).cpustat[index] += tmp;
129
130 #ifdef CONFIG_CGROUP_CPUACCT
131 if (unlikely(!cpuacct_subsys.active))
132 return;
133
134 rcu_read_lock();
135 ca = task_ca(p);
136 while (ca && (ca != &root_cpuacct)) {
137 kcpustat = this_cpu_ptr(ca->cpustat);
138 kcpustat->cpustat[index] += tmp;
139 ca = parent_ca(ca);
140 }
141 rcu_read_unlock();
142 #endif
143 }
144
145 /*
146 * Account user cpu time to a process.
147 * @p: the process that the cpu time gets accounted to
148 * @cputime: the cpu time spent in user space since the last update
149 * @cputime_scaled: cputime scaled by cpu frequency
150 */
151 void account_user_time(struct task_struct *p, cputime_t cputime,
152 cputime_t cputime_scaled)
153 {
154 int index;
155
156 /* Add user time to process. */
157 p->utime += cputime;
158 p->utimescaled += cputime_scaled;
159 account_group_user_time(p, cputime);
160
161 index = (TASK_NICE(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
162
163 /* Add user time to cpustat. */
164 task_group_account_field(p, index, (__force u64) cputime);
165
166 /* Account for user time used */
167 acct_account_cputime(p);
168 }
169
170 /*
171 * Account guest cpu time to a process.
172 * @p: the process that the cpu time gets accounted to
173 * @cputime: the cpu time spent in virtual machine since the last update
174 * @cputime_scaled: cputime scaled by cpu frequency
175 */
176 static void account_guest_time(struct task_struct *p, cputime_t cputime,
177 cputime_t cputime_scaled)
178 {
179 u64 *cpustat = kcpustat_this_cpu->cpustat;
180
181 /* Add guest time to process. */
182 p->utime += cputime;
183 p->utimescaled += cputime_scaled;
184 account_group_user_time(p, cputime);
185 p->gtime += cputime;
186
187 /* Add guest time to cpustat. */
188 if (TASK_NICE(p) > 0) {
189 cpustat[CPUTIME_NICE] += (__force u64) cputime;
190 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
191 } else {
192 cpustat[CPUTIME_USER] += (__force u64) cputime;
193 cpustat[CPUTIME_GUEST] += (__force u64) cputime;
194 }
195 }
196
197 /*
198 * Account system cpu time to a process and desired cpustat field
199 * @p: the process that the cpu time gets accounted to
200 * @cputime: the cpu time spent in kernel space since the last update
201 * @cputime_scaled: cputime scaled by cpu frequency
202 * @target_cputime64: pointer to cpustat field that has to be updated
203 */
204 static inline
205 void __account_system_time(struct task_struct *p, cputime_t cputime,
206 cputime_t cputime_scaled, int index)
207 {
208 /* Add system time to process. */
209 p->stime += cputime;
210 p->stimescaled += cputime_scaled;
211 account_group_system_time(p, cputime);
212
213 /* Add system time to cpustat. */
214 task_group_account_field(p, index, (__force u64) cputime);
215
216 /* Account for system time used */
217 acct_account_cputime(p);
218 }
219
220 /*
221 * Account system cpu time to a process.
222 * @p: the process that the cpu time gets accounted to
223 * @hardirq_offset: the offset to subtract from hardirq_count()
224 * @cputime: the cpu time spent in kernel space since the last update
225 * @cputime_scaled: cputime scaled by cpu frequency
226 */
227 void account_system_time(struct task_struct *p, int hardirq_offset,
228 cputime_t cputime, cputime_t cputime_scaled)
229 {
230 int index;
231
232 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
233 account_guest_time(p, cputime, cputime_scaled);
234 return;
235 }
236
237 if (hardirq_count() - hardirq_offset)
238 index = CPUTIME_IRQ;
239 else if (in_serving_softirq())
240 index = CPUTIME_SOFTIRQ;
241 else
242 index = CPUTIME_SYSTEM;
243
244 __account_system_time(p, cputime, cputime_scaled, index);
245 }
246
247 /*
248 * Account for involuntary wait time.
249 * @cputime: the cpu time spent in involuntary wait
250 */
251 void account_steal_time(cputime_t cputime)
252 {
253 u64 *cpustat = kcpustat_this_cpu->cpustat;
254
255 cpustat[CPUTIME_STEAL] += (__force u64) cputime;
256 }
257
258 /*
259 * Account for idle time.
260 * @cputime: the cpu time spent in idle wait
261 */
262 void account_idle_time(cputime_t cputime)
263 {
264 u64 *cpustat = kcpustat_this_cpu->cpustat;
265 struct rq *rq = this_rq();
266
267 if (atomic_read(&rq->nr_iowait) > 0)
268 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
269 else
270 cpustat[CPUTIME_IDLE] += (__force u64) cputime;
271 }
272
273 static __always_inline bool steal_account_process_tick(void)
274 {
275 #ifdef CONFIG_PARAVIRT
276 if (static_key_false(&paravirt_steal_enabled)) {
277 u64 steal, st = 0;
278
279 steal = paravirt_steal_clock(smp_processor_id());
280 steal -= this_rq()->prev_steal_time;
281
282 st = steal_ticks(steal);
283 this_rq()->prev_steal_time += st * TICK_NSEC;
284
285 account_steal_time(st);
286 return st;
287 }
288 #endif
289 return false;
290 }
291
292 /*
293 * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
294 * tasks (sum on group iteration) belonging to @tsk's group.
295 */
296 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
297 {
298 struct signal_struct *sig = tsk->signal;
299 cputime_t utime, stime;
300 struct task_struct *t;
301
302 times->utime = sig->utime;
303 times->stime = sig->stime;
304 times->sum_exec_runtime = sig->sum_sched_runtime;
305
306 rcu_read_lock();
307 /* make sure we can trust tsk->thread_group list */
308 if (!likely(pid_alive(tsk)))
309 goto out;
310
311 t = tsk;
312 do {
313 task_cputime(tsk, &utime, &stime);
314 times->utime += utime;
315 times->stime += stime;
316 times->sum_exec_runtime += task_sched_runtime(t);
317 } while_each_thread(tsk, t);
318 out:
319 rcu_read_unlock();
320 }
321
322 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
323 /*
324 * Account a tick to a process and cpustat
325 * @p: the process that the cpu time gets accounted to
326 * @user_tick: is the tick from userspace
327 * @rq: the pointer to rq
328 *
329 * Tick demultiplexing follows the order
330 * - pending hardirq update
331 * - pending softirq update
332 * - user_time
333 * - idle_time
334 * - system time
335 * - check for guest_time
336 * - else account as system_time
337 *
338 * Check for hardirq is done both for system and user time as there is
339 * no timer going off while we are on hardirq and hence we may never get an
340 * opportunity to update it solely in system time.
341 * p->stime and friends are only updated on system time and not on irq
342 * softirq as those do not count in task exec_runtime any more.
343 */
344 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
345 struct rq *rq)
346 {
347 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
348 u64 *cpustat = kcpustat_this_cpu->cpustat;
349
350 if (steal_account_process_tick())
351 return;
352
353 if (irqtime_account_hi_update()) {
354 cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
355 } else if (irqtime_account_si_update()) {
356 cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
357 } else if (this_cpu_ksoftirqd() == p) {
358 /*
359 * ksoftirqd time do not get accounted in cpu_softirq_time.
360 * So, we have to handle it separately here.
361 * Also, p->stime needs to be updated for ksoftirqd.
362 */
363 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
364 CPUTIME_SOFTIRQ);
365 } else if (user_tick) {
366 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
367 } else if (p == rq->idle) {
368 account_idle_time(cputime_one_jiffy);
369 } else if (p->flags & PF_VCPU) { /* System time or guest time */
370 account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
371 } else {
372 __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
373 CPUTIME_SYSTEM);
374 }
375 }
376
377 static void irqtime_account_idle_ticks(int ticks)
378 {
379 int i;
380 struct rq *rq = this_rq();
381
382 for (i = 0; i < ticks; i++)
383 irqtime_account_process_tick(current, 0, rq);
384 }
385 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
386 static inline void irqtime_account_idle_ticks(int ticks) {}
387 static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
388 struct rq *rq) {}
389 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
390
391 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
392 /*
393 * Account a single tick of cpu time.
394 * @p: the process that the cpu time gets accounted to
395 * @user_tick: indicates if the tick is a user or a system tick
396 */
397 void account_process_tick(struct task_struct *p, int user_tick)
398 {
399 cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
400 struct rq *rq = this_rq();
401
402 if (vtime_accounting_enabled())
403 return;
404
405 if (sched_clock_irqtime) {
406 irqtime_account_process_tick(p, user_tick, rq);
407 return;
408 }
409
410 if (steal_account_process_tick())
411 return;
412
413 if (user_tick)
414 account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
415 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
416 account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy,
417 one_jiffy_scaled);
418 else
419 account_idle_time(cputime_one_jiffy);
420 }
421
422 /*
423 * Account multiple ticks of steal time.
424 * @p: the process from which the cpu time has been stolen
425 * @ticks: number of stolen ticks
426 */
427 void account_steal_ticks(unsigned long ticks)
428 {
429 account_steal_time(jiffies_to_cputime(ticks));
430 }
431
432 /*
433 * Account multiple ticks of idle time.
434 * @ticks: number of stolen ticks
435 */
436 void account_idle_ticks(unsigned long ticks)
437 {
438
439 if (sched_clock_irqtime) {
440 irqtime_account_idle_ticks(ticks);
441 return;
442 }
443
444 account_idle_time(jiffies_to_cputime(ticks));
445 }
446 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
447
448 /*
449 * Use precise platform statistics if available:
450 */
451 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
452 void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
453 {
454 *ut = p->utime;
455 *st = p->stime;
456 }
457
458 void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
459 {
460 struct task_cputime cputime;
461
462 thread_group_cputime(p, &cputime);
463
464 *ut = cputime.utime;
465 *st = cputime.stime;
466 }
467
468 #ifndef __ARCH_HAS_VTIME_TASK_SWITCH
469 void vtime_task_switch(struct task_struct *prev)
470 {
471 if (!vtime_accounting_enabled())
472 return;
473
474 if (is_idle_task(prev))
475 vtime_account_idle(prev);
476 else
477 vtime_account_system(prev);
478
479 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
480 vtime_account_user(prev);
481 #endif
482 arch_vtime_task_switch(prev);
483 }
484 #endif
485
486 /*
487 * Archs that account the whole time spent in the idle task
488 * (outside irq) as idle time can rely on this and just implement
489 * vtime_account_system() and vtime_account_idle(). Archs that
490 * have other meaning of the idle time (s390 only includes the
491 * time spent by the CPU when it's in low power mode) must override
492 * vtime_account().
493 */
494 #ifndef __ARCH_HAS_VTIME_ACCOUNT
495 void vtime_account_irq_enter(struct task_struct *tsk)
496 {
497 if (!vtime_accounting_enabled())
498 return;
499
500 if (!in_interrupt()) {
501 /*
502 * If we interrupted user, context_tracking_in_user()
503 * is 1 because the context tracking don't hook
504 * on irq entry/exit. This way we know if
505 * we need to flush user time on kernel entry.
506 */
507 if (context_tracking_in_user()) {
508 vtime_account_user(tsk);
509 return;
510 }
511
512 if (is_idle_task(tsk)) {
513 vtime_account_idle(tsk);
514 return;
515 }
516 }
517 vtime_account_system(tsk);
518 }
519 EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
520 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
521
522 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
523
524 static cputime_t scale_stime(cputime_t stime, cputime_t rtime, cputime_t total)
525 {
526 u64 temp = (__force u64) rtime;
527
528 temp *= (__force u64) stime;
529
530 if (sizeof(cputime_t) == 4)
531 temp = div_u64(temp, (__force u32) total);
532 else
533 temp = div64_u64(temp, (__force u64) total);
534
535 return (__force cputime_t) temp;
536 }
537
538 /*
539 * Adjust tick based cputime random precision against scheduler
540 * runtime accounting.
541 */
542 static void cputime_adjust(struct task_cputime *curr,
543 struct cputime *prev,
544 cputime_t *ut, cputime_t *st)
545 {
546 cputime_t rtime, stime, total;
547
548 stime = curr->stime;
549 total = stime + curr->utime;
550
551 /*
552 * Tick based cputime accounting depend on random scheduling
553 * timeslices of a task to be interrupted or not by the timer.
554 * Depending on these circumstances, the number of these interrupts
555 * may be over or under-optimistic, matching the real user and system
556 * cputime with a variable precision.
557 *
558 * Fix this by scaling these tick based values against the total
559 * runtime accounted by the CFS scheduler.
560 */
561 rtime = nsecs_to_cputime(curr->sum_exec_runtime);
562
563 if (total)
564 stime = scale_stime(stime, rtime, total);
565 else
566 stime = rtime;
567
568 /*
569 * If the tick based count grows faster than the scheduler one,
570 * the result of the scaling may go backward.
571 * Let's enforce monotonicity.
572 */
573 prev->stime = max(prev->stime, stime);
574 prev->utime = max(prev->utime, rtime - prev->stime);
575
576 *ut = prev->utime;
577 *st = prev->stime;
578 }
579
580 void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
581 {
582 struct task_cputime cputime = {
583 .sum_exec_runtime = p->se.sum_exec_runtime,
584 };
585
586 task_cputime(p, &cputime.utime, &cputime.stime);
587 cputime_adjust(&cputime, &p->prev_cputime, ut, st);
588 }
589
590 /*
591 * Must be called with siglock held.
592 */
593 void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
594 {
595 struct task_cputime cputime;
596
597 thread_group_cputime(p, &cputime);
598 cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
599 }
600 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING */
601
602 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
603 static unsigned long long vtime_delta(struct task_struct *tsk)
604 {
605 unsigned long long clock;
606
607 clock = local_clock();
608 if (clock < tsk->vtime_snap)
609 return 0;
610
611 return clock - tsk->vtime_snap;
612 }
613
614 static cputime_t get_vtime_delta(struct task_struct *tsk)
615 {
616 unsigned long long delta = vtime_delta(tsk);
617
618 WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_SLEEPING);
619 tsk->vtime_snap += delta;
620
621 /* CHECKME: always safe to convert nsecs to cputime? */
622 return nsecs_to_cputime(delta);
623 }
624
625 static void __vtime_account_system(struct task_struct *tsk)
626 {
627 cputime_t delta_cpu = get_vtime_delta(tsk);
628
629 account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
630 }
631
632 void vtime_account_system(struct task_struct *tsk)
633 {
634 if (!vtime_accounting_enabled())
635 return;
636
637 write_seqlock(&tsk->vtime_seqlock);
638 __vtime_account_system(tsk);
639 write_sequnlock(&tsk->vtime_seqlock);
640 }
641
642 void vtime_account_irq_exit(struct task_struct *tsk)
643 {
644 if (!vtime_accounting_enabled())
645 return;
646
647 write_seqlock(&tsk->vtime_seqlock);
648 if (context_tracking_in_user())
649 tsk->vtime_snap_whence = VTIME_USER;
650 __vtime_account_system(tsk);
651 write_sequnlock(&tsk->vtime_seqlock);
652 }
653
654 void vtime_account_user(struct task_struct *tsk)
655 {
656 cputime_t delta_cpu;
657
658 if (!vtime_accounting_enabled())
659 return;
660
661 delta_cpu = get_vtime_delta(tsk);
662
663 write_seqlock(&tsk->vtime_seqlock);
664 tsk->vtime_snap_whence = VTIME_SYS;
665 account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
666 write_sequnlock(&tsk->vtime_seqlock);
667 }
668
669 void vtime_user_enter(struct task_struct *tsk)
670 {
671 if (!vtime_accounting_enabled())
672 return;
673
674 write_seqlock(&tsk->vtime_seqlock);
675 tsk->vtime_snap_whence = VTIME_USER;
676 __vtime_account_system(tsk);
677 write_sequnlock(&tsk->vtime_seqlock);
678 }
679
680 void vtime_guest_enter(struct task_struct *tsk)
681 {
682 write_seqlock(&tsk->vtime_seqlock);
683 __vtime_account_system(tsk);
684 current->flags |= PF_VCPU;
685 write_sequnlock(&tsk->vtime_seqlock);
686 }
687
688 void vtime_guest_exit(struct task_struct *tsk)
689 {
690 write_seqlock(&tsk->vtime_seqlock);
691 __vtime_account_system(tsk);
692 current->flags &= ~PF_VCPU;
693 write_sequnlock(&tsk->vtime_seqlock);
694 }
695
696 void vtime_account_idle(struct task_struct *tsk)
697 {
698 cputime_t delta_cpu = get_vtime_delta(tsk);
699
700 account_idle_time(delta_cpu);
701 }
702
703 bool vtime_accounting_enabled(void)
704 {
705 return context_tracking_active();
706 }
707
708 void arch_vtime_task_switch(struct task_struct *prev)
709 {
710 write_seqlock(&prev->vtime_seqlock);
711 prev->vtime_snap_whence = VTIME_SLEEPING;
712 write_sequnlock(&prev->vtime_seqlock);
713
714 write_seqlock(&current->vtime_seqlock);
715 current->vtime_snap_whence = VTIME_SYS;
716 current->vtime_snap = sched_clock();
717 write_sequnlock(&current->vtime_seqlock);
718 }
719
720 void vtime_init_idle(struct task_struct *t)
721 {
722 unsigned long flags;
723
724 write_seqlock_irqsave(&t->vtime_seqlock, flags);
725 t->vtime_snap_whence = VTIME_SYS;
726 t->vtime_snap = sched_clock();
727 write_sequnlock_irqrestore(&t->vtime_seqlock, flags);
728 }
729
730 cputime_t task_gtime(struct task_struct *t)
731 {
732 unsigned int seq;
733 cputime_t gtime;
734
735 do {
736 seq = read_seqbegin(&t->vtime_seqlock);
737
738 gtime = t->gtime;
739 if (t->flags & PF_VCPU)
740 gtime += vtime_delta(t);
741
742 } while (read_seqretry(&t->vtime_seqlock, seq));
743
744 return gtime;
745 }
746
747 /*
748 * Fetch cputime raw values from fields of task_struct and
749 * add up the pending nohz execution time since the last
750 * cputime snapshot.
751 */
752 static void
753 fetch_task_cputime(struct task_struct *t,
754 cputime_t *u_dst, cputime_t *s_dst,
755 cputime_t *u_src, cputime_t *s_src,
756 cputime_t *udelta, cputime_t *sdelta)
757 {
758 unsigned int seq;
759 unsigned long long delta;
760
761 do {
762 *udelta = 0;
763 *sdelta = 0;
764
765 seq = read_seqbegin(&t->vtime_seqlock);
766
767 if (u_dst)
768 *u_dst = *u_src;
769 if (s_dst)
770 *s_dst = *s_src;
771
772 /* Task is sleeping, nothing to add */
773 if (t->vtime_snap_whence == VTIME_SLEEPING ||
774 is_idle_task(t))
775 continue;
776
777 delta = vtime_delta(t);
778
779 /*
780 * Task runs either in user or kernel space, add pending nohz time to
781 * the right place.
782 */
783 if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) {
784 *udelta = delta;
785 } else {
786 if (t->vtime_snap_whence == VTIME_SYS)
787 *sdelta = delta;
788 }
789 } while (read_seqretry(&t->vtime_seqlock, seq));
790 }
791
792
793 void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
794 {
795 cputime_t udelta, sdelta;
796
797 fetch_task_cputime(t, utime, stime, &t->utime,
798 &t->stime, &udelta, &sdelta);
799 if (utime)
800 *utime += udelta;
801 if (stime)
802 *stime += sdelta;
803 }
804
805 void task_cputime_scaled(struct task_struct *t,
806 cputime_t *utimescaled, cputime_t *stimescaled)
807 {
808 cputime_t udelta, sdelta;
809
810 fetch_task_cputime(t, utimescaled, stimescaled,
811 &t->utimescaled, &t->stimescaled, &udelta, &sdelta);
812 if (utimescaled)
813 *utimescaled += cputime_to_scaled(udelta);
814 if (stimescaled)
815 *stimescaled += cputime_to_scaled(sdelta);
816 }
817 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */