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>
9 #include <asm/paravirt.h>
13 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
16 * There are no locks covering percpu hardirq/softirq time.
17 * They are only modified in vtime_account, on corresponding CPU
18 * with interrupts disabled. So, writes are safe.
19 * They are read and saved off onto struct rq in update_rq_clock().
20 * This may result in other CPU reading this CPU's irq time and can
21 * race with irq/vtime_account on this CPU. We would either get old
22 * or new value with a side effect of accounting a slice of irq time to wrong
23 * task when irq is in progress while we read rq->clock. That is a worthy
24 * compromise in place of having locks on each irq in account_system_time.
26 DEFINE_PER_CPU(u64, cpu_hardirq_time);
27 DEFINE_PER_CPU(u64, cpu_softirq_time);
29 static DEFINE_PER_CPU(u64, irq_start_time);
30 static int sched_clock_irqtime;
32 void enable_sched_clock_irqtime(void)
34 sched_clock_irqtime = 1;
37 void disable_sched_clock_irqtime(void)
39 sched_clock_irqtime = 0;
43 DEFINE_PER_CPU(seqcount_t, irq_time_seq);
44 #endif /* CONFIG_64BIT */
47 * Called before incrementing preempt_count on {soft,}irq_enter
48 * and before decrementing preempt_count on {soft,}irq_exit.
50 void irqtime_account_irq(struct task_struct *curr)
55 if (!sched_clock_irqtime)
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);
62 irq_time_write_begin();
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.
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);
76 EXPORT_SYMBOL_GPL(irqtime_account_irq);
78 static cputime_t irqtime_account_hi_update(cputime_t maxtime)
80 u64 *cpustat = kcpustat_this_cpu->cpustat;
82 cputime_t irq_cputime;
84 local_irq_save(flags);
85 irq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_hardirq_time)) -
87 irq_cputime = min(irq_cputime, maxtime);
88 cpustat[CPUTIME_IRQ] += irq_cputime;
89 local_irq_restore(flags);
93 static cputime_t irqtime_account_si_update(cputime_t maxtime)
95 u64 *cpustat = kcpustat_this_cpu->cpustat;
97 cputime_t softirq_cputime;
99 local_irq_save(flags);
100 softirq_cputime = nsecs_to_cputime64(this_cpu_read(cpu_softirq_time)) -
101 cpustat[CPUTIME_SOFTIRQ];
102 softirq_cputime = min(softirq_cputime, maxtime);
103 cpustat[CPUTIME_SOFTIRQ] += softirq_cputime;
104 local_irq_restore(flags);
105 return softirq_cputime;
108 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
110 #define sched_clock_irqtime (0)
112 static cputime_t irqtime_account_hi_update(cputime_t dummy)
117 static cputime_t irqtime_account_si_update(cputime_t dummy)
122 #endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
124 static inline void task_group_account_field(struct task_struct *p, int index,
128 * Since all updates are sure to touch the root cgroup, we
129 * get ourselves ahead and touch it first. If the root cgroup
130 * is the only cgroup, then nothing else should be necessary.
133 __this_cpu_add(kernel_cpustat.cpustat[index], tmp);
135 cpuacct_account_field(p, index, tmp);
139 * Account user cpu time to a process.
140 * @p: the process that the cpu time gets accounted to
141 * @cputime: the cpu time spent in user space since the last update
142 * @cputime_scaled: cputime scaled by cpu frequency
144 void account_user_time(struct task_struct *p, cputime_t cputime,
145 cputime_t cputime_scaled)
149 /* Add user time to process. */
151 p->utimescaled += cputime_scaled;
152 account_group_user_time(p, cputime);
154 index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
156 /* Add user time to cpustat. */
157 task_group_account_field(p, index, (__force u64) cputime);
159 /* Account for user time used */
160 acct_account_cputime(p);
164 * Account guest cpu time to a process.
165 * @p: the process that the cpu time gets accounted to
166 * @cputime: the cpu time spent in virtual machine since the last update
167 * @cputime_scaled: cputime scaled by cpu frequency
169 static void account_guest_time(struct task_struct *p, cputime_t cputime,
170 cputime_t cputime_scaled)
172 u64 *cpustat = kcpustat_this_cpu->cpustat;
174 /* Add guest time to process. */
176 p->utimescaled += cputime_scaled;
177 account_group_user_time(p, cputime);
180 /* Add guest time to cpustat. */
181 if (task_nice(p) > 0) {
182 cpustat[CPUTIME_NICE] += (__force u64) cputime;
183 cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime;
185 cpustat[CPUTIME_USER] += (__force u64) cputime;
186 cpustat[CPUTIME_GUEST] += (__force u64) cputime;
191 * Account system cpu time to a process and desired cpustat field
192 * @p: the process that the cpu time gets accounted to
193 * @cputime: the cpu time spent in kernel space since the last update
194 * @cputime_scaled: cputime scaled by cpu frequency
195 * @target_cputime64: pointer to cpustat field that has to be updated
198 void __account_system_time(struct task_struct *p, cputime_t cputime,
199 cputime_t cputime_scaled, int index)
201 /* Add system time to process. */
203 p->stimescaled += cputime_scaled;
204 account_group_system_time(p, cputime);
206 /* Add system time to cpustat. */
207 task_group_account_field(p, index, (__force u64) cputime);
209 /* Account for system time used */
210 acct_account_cputime(p);
214 * Account system cpu time to a process.
215 * @p: the process that the cpu time gets accounted to
216 * @hardirq_offset: the offset to subtract from hardirq_count()
217 * @cputime: the cpu time spent in kernel space since the last update
218 * @cputime_scaled: cputime scaled by cpu frequency
220 void account_system_time(struct task_struct *p, int hardirq_offset,
221 cputime_t cputime, cputime_t cputime_scaled)
225 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
226 account_guest_time(p, cputime, cputime_scaled);
230 if (hardirq_count() - hardirq_offset)
232 else if (in_serving_softirq())
233 index = CPUTIME_SOFTIRQ;
235 index = CPUTIME_SYSTEM;
237 __account_system_time(p, cputime, cputime_scaled, index);
241 * Account for involuntary wait time.
242 * @cputime: the cpu time spent in involuntary wait
244 void account_steal_time(cputime_t cputime)
246 u64 *cpustat = kcpustat_this_cpu->cpustat;
248 cpustat[CPUTIME_STEAL] += (__force u64) cputime;
252 * Account for idle time.
253 * @cputime: the cpu time spent in idle wait
255 void account_idle_time(cputime_t cputime)
257 u64 *cpustat = kcpustat_this_cpu->cpustat;
258 struct rq *rq = this_rq();
260 if (atomic_read(&rq->nr_iowait) > 0)
261 cpustat[CPUTIME_IOWAIT] += (__force u64) cputime;
263 cpustat[CPUTIME_IDLE] += (__force u64) cputime;
267 * When a guest is interrupted for a longer amount of time, missed clock
268 * ticks are not redelivered later. Due to that, this function may on
269 * occasion account more time than the calling functions think elapsed.
271 static __always_inline cputime_t steal_account_process_time(cputime_t maxtime)
273 #ifdef CONFIG_PARAVIRT
274 if (static_key_false(¶virt_steal_enabled)) {
275 cputime_t steal_cputime;
278 steal = paravirt_steal_clock(smp_processor_id());
279 steal -= this_rq()->prev_steal_time;
281 steal_cputime = min(nsecs_to_cputime(steal), maxtime);
282 account_steal_time(steal_cputime);
283 this_rq()->prev_steal_time += cputime_to_nsecs(steal_cputime);
285 return steal_cputime;
292 * Account how much elapsed time was spent in steal, irq, or softirq time.
294 static inline cputime_t account_other_time(cputime_t max)
298 accounted = steal_account_process_time(max);
301 accounted += irqtime_account_hi_update(max - accounted);
304 accounted += irqtime_account_si_update(max - accounted);
310 static inline u64 read_sum_exec_runtime(struct task_struct *t)
312 return t->se.sum_exec_runtime;
315 static u64 read_sum_exec_runtime(struct task_struct *t)
321 rq = task_rq_lock(t, &rf);
322 ns = t->se.sum_exec_runtime;
323 task_rq_unlock(rq, t, &rf);
330 * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
331 * tasks (sum on group iteration) belonging to @tsk's group.
333 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
335 struct signal_struct *sig = tsk->signal;
336 cputime_t utime, stime;
337 struct task_struct *t;
338 unsigned int seq, nextseq;
342 * Update current task runtime to account pending time since last
343 * scheduler action or thread_group_cputime() call. This thread group
344 * might have other running tasks on different CPUs, but updating
345 * their runtime can affect syscall performance, so we skip account
346 * those pending times and rely only on values updated on tick or
347 * other scheduler action.
349 if (same_thread_group(current, tsk))
350 (void) task_sched_runtime(current);
353 /* Attempt a lockless read on the first round. */
357 flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
358 times->utime = sig->utime;
359 times->stime = sig->stime;
360 times->sum_exec_runtime = sig->sum_sched_runtime;
362 for_each_thread(tsk, t) {
363 task_cputime(t, &utime, &stime);
364 times->utime += utime;
365 times->stime += stime;
366 times->sum_exec_runtime += read_sum_exec_runtime(t);
368 /* If lockless access failed, take the lock. */
370 } while (need_seqretry(&sig->stats_lock, seq));
371 done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
375 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
377 * Account a tick to a process and cpustat
378 * @p: the process that the cpu time gets accounted to
379 * @user_tick: is the tick from userspace
380 * @rq: the pointer to rq
382 * Tick demultiplexing follows the order
383 * - pending hardirq update
384 * - pending softirq update
388 * - check for guest_time
389 * - else account as system_time
391 * Check for hardirq is done both for system and user time as there is
392 * no timer going off while we are on hardirq and hence we may never get an
393 * opportunity to update it solely in system time.
394 * p->stime and friends are only updated on system time and not on irq
395 * softirq as those do not count in task exec_runtime any more.
397 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
398 struct rq *rq, int ticks)
400 u64 cputime = (__force u64) cputime_one_jiffy * ticks;
401 cputime_t scaled, other;
404 * When returning from idle, many ticks can get accounted at
405 * once, including some ticks of steal, irq, and softirq time.
406 * Subtract those ticks from the amount of time accounted to
407 * idle, or potentially user or system time. Due to rounding,
408 * other time can exceed ticks occasionally.
410 other = account_other_time(ULONG_MAX);
411 if (other >= cputime)
414 scaled = cputime_to_scaled(cputime);
416 if (this_cpu_ksoftirqd() == p) {
418 * ksoftirqd time do not get accounted in cpu_softirq_time.
419 * So, we have to handle it separately here.
420 * Also, p->stime needs to be updated for ksoftirqd.
422 __account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ);
423 } else if (user_tick) {
424 account_user_time(p, cputime, scaled);
425 } else if (p == rq->idle) {
426 account_idle_time(cputime);
427 } else if (p->flags & PF_VCPU) { /* System time or guest time */
428 account_guest_time(p, cputime, scaled);
430 __account_system_time(p, cputime, scaled, CPUTIME_SYSTEM);
434 static void irqtime_account_idle_ticks(int ticks)
436 struct rq *rq = this_rq();
438 irqtime_account_process_tick(current, 0, rq, ticks);
440 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
441 static inline void irqtime_account_idle_ticks(int ticks) {}
442 static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
443 struct rq *rq, int nr_ticks) {}
444 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
447 * Use precise platform statistics if available:
449 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
451 #ifndef __ARCH_HAS_VTIME_TASK_SWITCH
452 void vtime_common_task_switch(struct task_struct *prev)
454 if (is_idle_task(prev))
455 vtime_account_idle(prev);
457 vtime_account_system(prev);
459 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
460 vtime_account_user(prev);
462 arch_vtime_task_switch(prev);
466 #endif /* CONFIG_VIRT_CPU_ACCOUNTING */
469 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
471 * Archs that account the whole time spent in the idle task
472 * (outside irq) as idle time can rely on this and just implement
473 * vtime_account_system() and vtime_account_idle(). Archs that
474 * have other meaning of the idle time (s390 only includes the
475 * time spent by the CPU when it's in low power mode) must override
478 #ifndef __ARCH_HAS_VTIME_ACCOUNT
479 void vtime_account_irq_enter(struct task_struct *tsk)
481 if (!in_interrupt() && is_idle_task(tsk))
482 vtime_account_idle(tsk);
484 vtime_account_system(tsk);
486 EXPORT_SYMBOL_GPL(vtime_account_irq_enter);
487 #endif /* __ARCH_HAS_VTIME_ACCOUNT */
489 void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
494 EXPORT_SYMBOL_GPL(task_cputime_adjusted);
496 void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
498 struct task_cputime cputime;
500 thread_group_cputime(p, &cputime);
505 #else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
507 * Account a single tick of cpu time.
508 * @p: the process that the cpu time gets accounted to
509 * @user_tick: indicates if the tick is a user or a system tick
511 void account_process_tick(struct task_struct *p, int user_tick)
513 cputime_t cputime, scaled, steal;
514 struct rq *rq = this_rq();
516 if (vtime_accounting_cpu_enabled())
519 if (sched_clock_irqtime) {
520 irqtime_account_process_tick(p, user_tick, rq, 1);
524 cputime = cputime_one_jiffy;
525 steal = steal_account_process_time(ULONG_MAX);
527 if (steal >= cputime)
531 scaled = cputime_to_scaled(cputime);
534 account_user_time(p, cputime, scaled);
535 else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET))
536 account_system_time(p, HARDIRQ_OFFSET, cputime, scaled);
538 account_idle_time(cputime);
542 * Account multiple ticks of idle time.
543 * @ticks: number of stolen ticks
545 void account_idle_ticks(unsigned long ticks)
547 cputime_t cputime, steal;
549 if (sched_clock_irqtime) {
550 irqtime_account_idle_ticks(ticks);
554 cputime = jiffies_to_cputime(ticks);
555 steal = steal_account_process_time(ULONG_MAX);
557 if (steal >= cputime)
561 account_idle_time(cputime);
565 * Perform (stime * rtime) / total, but avoid multiplication overflow by
566 * loosing precision when the numbers are big.
568 static cputime_t scale_stime(u64 stime, u64 rtime, u64 total)
573 /* Make sure "rtime" is the bigger of stime/rtime */
577 /* Make sure 'total' fits in 32 bits */
581 /* Does rtime (and thus stime) fit in 32 bits? */
585 /* Can we just balance rtime/stime rather than dropping bits? */
589 /* We can grow stime and shrink rtime and try to make them both fit */
595 /* We drop from rtime, it has more bits than stime */
601 * Make sure gcc understands that this is a 32x32->64 multiply,
602 * followed by a 64/32->64 divide.
604 scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total);
605 return (__force cputime_t) scaled;
609 * Adjust tick based cputime random precision against scheduler runtime
612 * Tick based cputime accounting depend on random scheduling timeslices of a
613 * task to be interrupted or not by the timer. Depending on these
614 * circumstances, the number of these interrupts may be over or
615 * under-optimistic, matching the real user and system cputime with a variable
618 * Fix this by scaling these tick based values against the total runtime
619 * accounted by the CFS scheduler.
621 * This code provides the following guarantees:
623 * stime + utime == rtime
624 * stime_i+1 >= stime_i, utime_i+1 >= utime_i
626 * Assuming that rtime_i+1 >= rtime_i.
628 static void cputime_adjust(struct task_cputime *curr,
629 struct prev_cputime *prev,
630 cputime_t *ut, cputime_t *st)
632 cputime_t rtime, stime, utime;
635 /* Serialize concurrent callers such that we can honour our guarantees */
636 raw_spin_lock_irqsave(&prev->lock, flags);
637 rtime = nsecs_to_cputime(curr->sum_exec_runtime);
640 * This is possible under two circumstances:
641 * - rtime isn't monotonic after all (a bug);
642 * - we got reordered by the lock.
644 * In both cases this acts as a filter such that the rest of the code
645 * can assume it is monotonic regardless of anything else.
647 if (prev->stime + prev->utime >= rtime)
654 * If either stime or both stime and utime are 0, assume all runtime is
655 * userspace. Once a task gets some ticks, the monotonicy code at
656 * 'update' will ensure things converge to the observed ratio.
668 stime = scale_stime((__force u64)stime, (__force u64)rtime,
669 (__force u64)(stime + utime));
673 * Make sure stime doesn't go backwards; this preserves monotonicity
674 * for utime because rtime is monotonic.
676 * utime_i+1 = rtime_i+1 - stime_i
677 * = rtime_i+1 - (rtime_i - utime_i)
678 * = (rtime_i+1 - rtime_i) + utime_i
681 if (stime < prev->stime)
683 utime = rtime - stime;
686 * Make sure utime doesn't go backwards; this still preserves
687 * monotonicity for stime, analogous argument to above.
689 if (utime < prev->utime) {
691 stime = rtime - utime;
699 raw_spin_unlock_irqrestore(&prev->lock, flags);
702 void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
704 struct task_cputime cputime = {
705 .sum_exec_runtime = p->se.sum_exec_runtime,
708 task_cputime(p, &cputime.utime, &cputime.stime);
709 cputime_adjust(&cputime, &p->prev_cputime, ut, st);
711 EXPORT_SYMBOL_GPL(task_cputime_adjusted);
713 void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st)
715 struct task_cputime cputime;
717 thread_group_cputime(p, &cputime);
718 cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
720 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
722 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
723 static cputime_t vtime_delta(struct task_struct *tsk)
725 unsigned long now = READ_ONCE(jiffies);
727 if (time_before(now, (unsigned long)tsk->vtime_snap))
730 return jiffies_to_cputime(now - tsk->vtime_snap);
733 static cputime_t get_vtime_delta(struct task_struct *tsk)
735 unsigned long now = READ_ONCE(jiffies);
736 cputime_t delta, other;
739 * Unlike tick based timing, vtime based timing never has lost
740 * ticks, and no need for steal time accounting to make up for
741 * lost ticks. Vtime accounts a rounded version of actual
742 * elapsed time. Limit account_other_time to prevent rounding
743 * errors from causing elapsed vtime to go negative.
745 delta = jiffies_to_cputime(now - tsk->vtime_snap);
746 other = account_other_time(delta);
747 WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_INACTIVE);
748 tsk->vtime_snap = now;
750 return delta - other;
753 static void __vtime_account_system(struct task_struct *tsk)
755 cputime_t delta_cpu = get_vtime_delta(tsk);
757 account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
760 void vtime_account_system(struct task_struct *tsk)
762 if (!vtime_delta(tsk))
765 write_seqcount_begin(&tsk->vtime_seqcount);
766 __vtime_account_system(tsk);
767 write_seqcount_end(&tsk->vtime_seqcount);
770 void vtime_account_user(struct task_struct *tsk)
774 write_seqcount_begin(&tsk->vtime_seqcount);
775 tsk->vtime_snap_whence = VTIME_SYS;
776 if (vtime_delta(tsk)) {
777 delta_cpu = get_vtime_delta(tsk);
778 account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
780 write_seqcount_end(&tsk->vtime_seqcount);
783 void vtime_user_enter(struct task_struct *tsk)
785 write_seqcount_begin(&tsk->vtime_seqcount);
786 if (vtime_delta(tsk))
787 __vtime_account_system(tsk);
788 tsk->vtime_snap_whence = VTIME_USER;
789 write_seqcount_end(&tsk->vtime_seqcount);
792 void vtime_guest_enter(struct task_struct *tsk)
795 * The flags must be updated under the lock with
796 * the vtime_snap flush and update.
797 * That enforces a right ordering and update sequence
798 * synchronization against the reader (task_gtime())
799 * that can thus safely catch up with a tickless delta.
801 write_seqcount_begin(&tsk->vtime_seqcount);
802 if (vtime_delta(tsk))
803 __vtime_account_system(tsk);
804 current->flags |= PF_VCPU;
805 write_seqcount_end(&tsk->vtime_seqcount);
807 EXPORT_SYMBOL_GPL(vtime_guest_enter);
809 void vtime_guest_exit(struct task_struct *tsk)
811 write_seqcount_begin(&tsk->vtime_seqcount);
812 __vtime_account_system(tsk);
813 current->flags &= ~PF_VCPU;
814 write_seqcount_end(&tsk->vtime_seqcount);
816 EXPORT_SYMBOL_GPL(vtime_guest_exit);
818 void vtime_account_idle(struct task_struct *tsk)
820 cputime_t delta_cpu = get_vtime_delta(tsk);
822 account_idle_time(delta_cpu);
825 void arch_vtime_task_switch(struct task_struct *prev)
827 write_seqcount_begin(&prev->vtime_seqcount);
828 prev->vtime_snap_whence = VTIME_INACTIVE;
829 write_seqcount_end(&prev->vtime_seqcount);
831 write_seqcount_begin(¤t->vtime_seqcount);
832 current->vtime_snap_whence = VTIME_SYS;
833 current->vtime_snap = jiffies;
834 write_seqcount_end(¤t->vtime_seqcount);
837 void vtime_init_idle(struct task_struct *t, int cpu)
841 local_irq_save(flags);
842 write_seqcount_begin(&t->vtime_seqcount);
843 t->vtime_snap_whence = VTIME_SYS;
844 t->vtime_snap = jiffies;
845 write_seqcount_end(&t->vtime_seqcount);
846 local_irq_restore(flags);
849 cputime_t task_gtime(struct task_struct *t)
854 if (!vtime_accounting_enabled())
858 seq = read_seqcount_begin(&t->vtime_seqcount);
861 if (t->vtime_snap_whence == VTIME_SYS && t->flags & PF_VCPU)
862 gtime += vtime_delta(t);
864 } while (read_seqcount_retry(&t->vtime_seqcount, seq));
870 * Fetch cputime raw values from fields of task_struct and
871 * add up the pending nohz execution time since the last
875 fetch_task_cputime(struct task_struct *t,
876 cputime_t *u_dst, cputime_t *s_dst,
877 cputime_t *u_src, cputime_t *s_src,
878 cputime_t *udelta, cputime_t *sdelta)
881 unsigned long long delta;
887 seq = read_seqcount_begin(&t->vtime_seqcount);
894 /* Task is sleeping, nothing to add */
895 if (t->vtime_snap_whence == VTIME_INACTIVE ||
899 delta = vtime_delta(t);
902 * Task runs either in user or kernel space, add pending nohz time to
905 if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) {
908 if (t->vtime_snap_whence == VTIME_SYS)
911 } while (read_seqcount_retry(&t->vtime_seqcount, seq));
915 void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime)
917 cputime_t udelta, sdelta;
919 if (!vtime_accounting_enabled()) {
927 fetch_task_cputime(t, utime, stime, &t->utime,
928 &t->stime, &udelta, &sdelta);
935 void task_cputime_scaled(struct task_struct *t,
936 cputime_t *utimescaled, cputime_t *stimescaled)
938 cputime_t udelta, sdelta;
940 if (!vtime_accounting_enabled()) {
942 *utimescaled = t->utimescaled;
944 *stimescaled = t->stimescaled;
948 fetch_task_cputime(t, utimescaled, stimescaled,
949 &t->utimescaled, &t->stimescaled, &udelta, &sdelta);
951 *utimescaled += cputime_to_scaled(udelta);
953 *stimescaled += cputime_to_scaled(sdelta);
955 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */