1 // SPDX-License-Identifier: GPL-2.0-only
3 * Simple CPU accounting cgroup controller
6 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
9 * There are no locks covering percpu hardirq/softirq time.
10 * They are only modified in vtime_account, on corresponding CPU
11 * with interrupts disabled. So, writes are safe.
12 * They are read and saved off onto struct rq in update_rq_clock().
13 * This may result in other CPU reading this CPU's irq time and can
14 * race with irq/vtime_account on this CPU. We would either get old
15 * or new value with a side effect of accounting a slice of irq time to wrong
16 * task when irq is in progress while we read rq->clock. That is a worthy
17 * compromise in place of having locks on each irq in account_system_time.
19 DEFINE_PER_CPU(struct irqtime, cpu_irqtime);
21 static int sched_clock_irqtime;
23 void enable_sched_clock_irqtime(void)
25 sched_clock_irqtime = 1;
28 void disable_sched_clock_irqtime(void)
30 sched_clock_irqtime = 0;
33 static void irqtime_account_delta(struct irqtime *irqtime, u64 delta,
34 enum cpu_usage_stat idx)
36 u64 *cpustat = kcpustat_this_cpu->cpustat;
38 u64_stats_update_begin(&irqtime->sync);
39 cpustat[idx] += delta;
40 irqtime->total += delta;
41 irqtime->tick_delta += delta;
42 u64_stats_update_end(&irqtime->sync);
46 * Called after incrementing preempt_count on {soft,}irq_enter
47 * and before decrementing preempt_count on {soft,}irq_exit.
49 void irqtime_account_irq(struct task_struct *curr, unsigned int offset)
51 struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
56 if (!sched_clock_irqtime)
59 cpu = smp_processor_id();
60 delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
61 irqtime->irq_start_time += delta;
62 pc = irq_count() - offset;
65 * We do not account for softirq time from ksoftirqd here.
66 * We want to continue accounting softirq time to ksoftirqd thread
67 * in that case, so as not to confuse scheduler with a special task
68 * that do not consume any time, but still wants to run.
70 if (pc & HARDIRQ_MASK)
71 irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
72 else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd())
73 irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
76 static u64 irqtime_tick_accounted(u64 maxtime)
78 struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
81 delta = min(irqtime->tick_delta, maxtime);
82 irqtime->tick_delta -= delta;
87 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
89 #define sched_clock_irqtime (0)
91 static u64 irqtime_tick_accounted(u64 dummy)
96 #endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
98 static inline void task_group_account_field(struct task_struct *p, int index,
102 * Since all updates are sure to touch the root cgroup, we
103 * get ourselves ahead and touch it first. If the root cgroup
104 * is the only cgroup, then nothing else should be necessary.
107 __this_cpu_add(kernel_cpustat.cpustat[index], tmp);
109 cgroup_account_cputime_field(p, index, tmp);
113 * Account user CPU time to a process.
114 * @p: the process that the CPU time gets accounted to
115 * @cputime: the CPU time spent in user space since the last update
117 void account_user_time(struct task_struct *p, u64 cputime)
121 /* Add user time to process. */
123 account_group_user_time(p, cputime);
125 index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
127 /* Add user time to cpustat. */
128 task_group_account_field(p, index, cputime);
130 /* Account for user time used */
131 acct_account_cputime(p);
135 * Account guest CPU time to a process.
136 * @p: the process that the CPU time gets accounted to
137 * @cputime: the CPU time spent in virtual machine since the last update
139 void account_guest_time(struct task_struct *p, u64 cputime)
141 u64 *cpustat = kcpustat_this_cpu->cpustat;
143 /* Add guest time to process. */
145 account_group_user_time(p, cputime);
148 /* Add guest time to cpustat. */
149 if (task_nice(p) > 0) {
150 task_group_account_field(p, CPUTIME_NICE, cputime);
151 cpustat[CPUTIME_GUEST_NICE] += cputime;
153 task_group_account_field(p, CPUTIME_USER, cputime);
154 cpustat[CPUTIME_GUEST] += cputime;
159 * Account system CPU time to a process and desired cpustat field
160 * @p: the process that the CPU time gets accounted to
161 * @cputime: the CPU time spent in kernel space since the last update
162 * @index: pointer to cpustat field that has to be updated
164 void account_system_index_time(struct task_struct *p,
165 u64 cputime, enum cpu_usage_stat index)
167 /* Add system time to process. */
169 account_group_system_time(p, cputime);
171 /* Add system time to cpustat. */
172 task_group_account_field(p, index, cputime);
174 /* Account for system time used */
175 acct_account_cputime(p);
179 * Account system CPU time to a process.
180 * @p: the process that the CPU time gets accounted to
181 * @hardirq_offset: the offset to subtract from hardirq_count()
182 * @cputime: the CPU time spent in kernel space since the last update
184 void account_system_time(struct task_struct *p, int hardirq_offset, u64 cputime)
188 if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
189 account_guest_time(p, cputime);
193 if (hardirq_count() - hardirq_offset)
195 else if (in_serving_softirq())
196 index = CPUTIME_SOFTIRQ;
198 index = CPUTIME_SYSTEM;
200 account_system_index_time(p, cputime, index);
204 * Account for involuntary wait time.
205 * @cputime: the CPU time spent in involuntary wait
207 void account_steal_time(u64 cputime)
209 u64 *cpustat = kcpustat_this_cpu->cpustat;
211 cpustat[CPUTIME_STEAL] += cputime;
215 * Account for idle time.
216 * @cputime: the CPU time spent in idle wait
218 void account_idle_time(u64 cputime)
220 u64 *cpustat = kcpustat_this_cpu->cpustat;
221 struct rq *rq = this_rq();
223 if (atomic_read(&rq->nr_iowait) > 0)
224 cpustat[CPUTIME_IOWAIT] += cputime;
226 cpustat[CPUTIME_IDLE] += cputime;
230 #ifdef CONFIG_SCHED_CORE
232 * Account for forceidle time due to core scheduling.
234 * REQUIRES: schedstat is enabled.
236 void __account_forceidle_time(struct task_struct *p, u64 delta)
238 __schedstat_add(p->stats.core_forceidle_sum, delta);
240 task_group_account_field(p, CPUTIME_FORCEIDLE, delta);
245 * When a guest is interrupted for a longer amount of time, missed clock
246 * ticks are not redelivered later. Due to that, this function may on
247 * occasion account more time than the calling functions think elapsed.
249 static __always_inline u64 steal_account_process_time(u64 maxtime)
251 #ifdef CONFIG_PARAVIRT
252 if (static_key_false(¶virt_steal_enabled)) {
255 steal = paravirt_steal_clock(smp_processor_id());
256 steal -= this_rq()->prev_steal_time;
257 steal = min(steal, maxtime);
258 account_steal_time(steal);
259 this_rq()->prev_steal_time += steal;
268 * Account how much elapsed time was spent in steal, irq, or softirq time.
270 static inline u64 account_other_time(u64 max)
274 lockdep_assert_irqs_disabled();
276 accounted = steal_account_process_time(max);
279 accounted += irqtime_tick_accounted(max - accounted);
285 static inline u64 read_sum_exec_runtime(struct task_struct *t)
287 return t->se.sum_exec_runtime;
290 static u64 read_sum_exec_runtime(struct task_struct *t)
296 rq = task_rq_lock(t, &rf);
297 ns = t->se.sum_exec_runtime;
298 task_rq_unlock(rq, t, &rf);
305 * Accumulate raw cputime values of dead tasks (sig->[us]time) and live
306 * tasks (sum on group iteration) belonging to @tsk's group.
308 void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times)
310 struct signal_struct *sig = tsk->signal;
312 struct task_struct *t;
313 unsigned int seq, nextseq;
317 * Update current task runtime to account pending time since last
318 * scheduler action or thread_group_cputime() call. This thread group
319 * might have other running tasks on different CPUs, but updating
320 * their runtime can affect syscall performance, so we skip account
321 * those pending times and rely only on values updated on tick or
322 * other scheduler action.
324 if (same_thread_group(current, tsk))
325 (void) task_sched_runtime(current);
328 /* Attempt a lockless read on the first round. */
332 flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq);
333 times->utime = sig->utime;
334 times->stime = sig->stime;
335 times->sum_exec_runtime = sig->sum_sched_runtime;
337 for_each_thread(tsk, t) {
338 task_cputime(t, &utime, &stime);
339 times->utime += utime;
340 times->stime += stime;
341 times->sum_exec_runtime += read_sum_exec_runtime(t);
343 /* If lockless access failed, take the lock. */
345 } while (need_seqretry(&sig->stats_lock, seq));
346 done_seqretry_irqrestore(&sig->stats_lock, seq, flags);
350 #ifdef CONFIG_IRQ_TIME_ACCOUNTING
352 * Account a tick to a process and cpustat
353 * @p: the process that the CPU time gets accounted to
354 * @user_tick: is the tick from userspace
355 * @rq: the pointer to rq
357 * Tick demultiplexing follows the order
358 * - pending hardirq update
359 * - pending softirq update
363 * - check for guest_time
364 * - else account as system_time
366 * Check for hardirq is done both for system and user time as there is
367 * no timer going off while we are on hardirq and hence we may never get an
368 * opportunity to update it solely in system time.
369 * p->stime and friends are only updated on system time and not on irq
370 * softirq as those do not count in task exec_runtime any more.
372 static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
375 u64 other, cputime = TICK_NSEC * ticks;
378 * When returning from idle, many ticks can get accounted at
379 * once, including some ticks of steal, irq, and softirq time.
380 * Subtract those ticks from the amount of time accounted to
381 * idle, or potentially user or system time. Due to rounding,
382 * other time can exceed ticks occasionally.
384 other = account_other_time(ULONG_MAX);
385 if (other >= cputime)
390 if (this_cpu_ksoftirqd() == p) {
392 * ksoftirqd time do not get accounted in cpu_softirq_time.
393 * So, we have to handle it separately here.
394 * Also, p->stime needs to be updated for ksoftirqd.
396 account_system_index_time(p, cputime, CPUTIME_SOFTIRQ);
397 } else if (user_tick) {
398 account_user_time(p, cputime);
399 } else if (p == this_rq()->idle) {
400 account_idle_time(cputime);
401 } else if (p->flags & PF_VCPU) { /* System time or guest time */
402 account_guest_time(p, cputime);
404 account_system_index_time(p, cputime, CPUTIME_SYSTEM);
408 static void irqtime_account_idle_ticks(int ticks)
410 irqtime_account_process_tick(current, 0, ticks);
412 #else /* CONFIG_IRQ_TIME_ACCOUNTING */
413 static inline void irqtime_account_idle_ticks(int ticks) { }
414 static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
416 #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
419 * Use precise platform statistics if available:
421 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
423 # ifndef __ARCH_HAS_VTIME_TASK_SWITCH
424 void vtime_task_switch(struct task_struct *prev)
426 if (is_idle_task(prev))
427 vtime_account_idle(prev);
429 vtime_account_kernel(prev);
432 arch_vtime_task_switch(prev);
436 void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
438 unsigned int pc = irq_count() - offset;
440 if (pc & HARDIRQ_OFFSET) {
441 vtime_account_hardirq(tsk);
442 } else if (pc & SOFTIRQ_OFFSET) {
443 vtime_account_softirq(tsk);
444 } else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
446 vtime_account_idle(tsk);
448 vtime_account_kernel(tsk);
452 void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
459 void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
464 EXPORT_SYMBOL_GPL(task_cputime_adjusted);
466 void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
468 struct task_cputime cputime;
470 thread_group_cputime(p, &cputime);
476 #else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE: */
479 * Account a single tick of CPU time.
480 * @p: the process that the CPU time gets accounted to
481 * @user_tick: indicates if the tick is a user or a system tick
483 void account_process_tick(struct task_struct *p, int user_tick)
487 if (vtime_accounting_enabled_this_cpu())
490 if (sched_clock_irqtime) {
491 irqtime_account_process_tick(p, user_tick, 1);
496 steal = steal_account_process_time(ULONG_MAX);
498 if (steal >= cputime)
504 account_user_time(p, cputime);
505 else if ((p != this_rq()->idle) || (irq_count() != HARDIRQ_OFFSET))
506 account_system_time(p, HARDIRQ_OFFSET, cputime);
508 account_idle_time(cputime);
512 * Account multiple ticks of idle time.
513 * @ticks: number of stolen ticks
515 void account_idle_ticks(unsigned long ticks)
519 if (sched_clock_irqtime) {
520 irqtime_account_idle_ticks(ticks);
524 cputime = ticks * TICK_NSEC;
525 steal = steal_account_process_time(ULONG_MAX);
527 if (steal >= cputime)
531 account_idle_time(cputime);
535 * Adjust tick based cputime random precision against scheduler runtime
538 * Tick based cputime accounting depend on random scheduling timeslices of a
539 * task to be interrupted or not by the timer. Depending on these
540 * circumstances, the number of these interrupts may be over or
541 * under-optimistic, matching the real user and system cputime with a variable
544 * Fix this by scaling these tick based values against the total runtime
545 * accounted by the CFS scheduler.
547 * This code provides the following guarantees:
549 * stime + utime == rtime
550 * stime_i+1 >= stime_i, utime_i+1 >= utime_i
552 * Assuming that rtime_i+1 >= rtime_i.
554 void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev,
557 u64 rtime, stime, utime;
560 /* Serialize concurrent callers such that we can honour our guarantees */
561 raw_spin_lock_irqsave(&prev->lock, flags);
562 rtime = curr->sum_exec_runtime;
565 * This is possible under two circumstances:
566 * - rtime isn't monotonic after all (a bug);
567 * - we got reordered by the lock.
569 * In both cases this acts as a filter such that the rest of the code
570 * can assume it is monotonic regardless of anything else.
572 if (prev->stime + prev->utime >= rtime)
579 * If either stime or utime are 0, assume all runtime is userspace.
580 * Once a task gets some ticks, the monotonicity code at 'update:'
581 * will ensure things converge to the observed ratio.
593 stime = mul_u64_u64_div_u64(stime, rtime, stime + utime);
597 * Make sure stime doesn't go backwards; this preserves monotonicity
598 * for utime because rtime is monotonic.
600 * utime_i+1 = rtime_i+1 - stime_i
601 * = rtime_i+1 - (rtime_i - utime_i)
602 * = (rtime_i+1 - rtime_i) + utime_i
605 if (stime < prev->stime)
607 utime = rtime - stime;
610 * Make sure utime doesn't go backwards; this still preserves
611 * monotonicity for stime, analogous argument to above.
613 if (utime < prev->utime) {
615 stime = rtime - utime;
623 raw_spin_unlock_irqrestore(&prev->lock, flags);
626 void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
628 struct task_cputime cputime = {
629 .sum_exec_runtime = p->se.sum_exec_runtime,
632 if (task_cputime(p, &cputime.utime, &cputime.stime))
633 cputime.sum_exec_runtime = task_sched_runtime(p);
634 cputime_adjust(&cputime, &p->prev_cputime, ut, st);
636 EXPORT_SYMBOL_GPL(task_cputime_adjusted);
638 void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st)
640 struct task_cputime cputime;
642 thread_group_cputime(p, &cputime);
643 cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st);
645 #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */
647 #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
648 static u64 vtime_delta(struct vtime *vtime)
650 unsigned long long clock;
652 clock = sched_clock();
653 if (clock < vtime->starttime)
656 return clock - vtime->starttime;
659 static u64 get_vtime_delta(struct vtime *vtime)
661 u64 delta = vtime_delta(vtime);
665 * Unlike tick based timing, vtime based timing never has lost
666 * ticks, and no need for steal time accounting to make up for
667 * lost ticks. Vtime accounts a rounded version of actual
668 * elapsed time. Limit account_other_time to prevent rounding
669 * errors from causing elapsed vtime to go negative.
671 other = account_other_time(delta);
672 WARN_ON_ONCE(vtime->state == VTIME_INACTIVE);
673 vtime->starttime += delta;
675 return delta - other;
678 static void vtime_account_system(struct task_struct *tsk,
681 vtime->stime += get_vtime_delta(vtime);
682 if (vtime->stime >= TICK_NSEC) {
683 account_system_time(tsk, irq_count(), vtime->stime);
688 static void vtime_account_guest(struct task_struct *tsk,
691 vtime->gtime += get_vtime_delta(vtime);
692 if (vtime->gtime >= TICK_NSEC) {
693 account_guest_time(tsk, vtime->gtime);
698 static void __vtime_account_kernel(struct task_struct *tsk,
701 /* We might have scheduled out from guest path */
702 if (vtime->state == VTIME_GUEST)
703 vtime_account_guest(tsk, vtime);
705 vtime_account_system(tsk, vtime);
708 void vtime_account_kernel(struct task_struct *tsk)
710 struct vtime *vtime = &tsk->vtime;
712 if (!vtime_delta(vtime))
715 write_seqcount_begin(&vtime->seqcount);
716 __vtime_account_kernel(tsk, vtime);
717 write_seqcount_end(&vtime->seqcount);
720 void vtime_user_enter(struct task_struct *tsk)
722 struct vtime *vtime = &tsk->vtime;
724 write_seqcount_begin(&vtime->seqcount);
725 vtime_account_system(tsk, vtime);
726 vtime->state = VTIME_USER;
727 write_seqcount_end(&vtime->seqcount);
730 void vtime_user_exit(struct task_struct *tsk)
732 struct vtime *vtime = &tsk->vtime;
734 write_seqcount_begin(&vtime->seqcount);
735 vtime->utime += get_vtime_delta(vtime);
736 if (vtime->utime >= TICK_NSEC) {
737 account_user_time(tsk, vtime->utime);
740 vtime->state = VTIME_SYS;
741 write_seqcount_end(&vtime->seqcount);
744 void vtime_guest_enter(struct task_struct *tsk)
746 struct vtime *vtime = &tsk->vtime;
748 * The flags must be updated under the lock with
749 * the vtime_starttime flush and update.
750 * That enforces a right ordering and update sequence
751 * synchronization against the reader (task_gtime())
752 * that can thus safely catch up with a tickless delta.
754 write_seqcount_begin(&vtime->seqcount);
755 vtime_account_system(tsk, vtime);
756 tsk->flags |= PF_VCPU;
757 vtime->state = VTIME_GUEST;
758 write_seqcount_end(&vtime->seqcount);
760 EXPORT_SYMBOL_GPL(vtime_guest_enter);
762 void vtime_guest_exit(struct task_struct *tsk)
764 struct vtime *vtime = &tsk->vtime;
766 write_seqcount_begin(&vtime->seqcount);
767 vtime_account_guest(tsk, vtime);
768 tsk->flags &= ~PF_VCPU;
769 vtime->state = VTIME_SYS;
770 write_seqcount_end(&vtime->seqcount);
772 EXPORT_SYMBOL_GPL(vtime_guest_exit);
774 void vtime_account_idle(struct task_struct *tsk)
776 account_idle_time(get_vtime_delta(&tsk->vtime));
779 void vtime_task_switch_generic(struct task_struct *prev)
781 struct vtime *vtime = &prev->vtime;
783 write_seqcount_begin(&vtime->seqcount);
784 if (vtime->state == VTIME_IDLE)
785 vtime_account_idle(prev);
787 __vtime_account_kernel(prev, vtime);
788 vtime->state = VTIME_INACTIVE;
790 write_seqcount_end(&vtime->seqcount);
792 vtime = ¤t->vtime;
794 write_seqcount_begin(&vtime->seqcount);
795 if (is_idle_task(current))
796 vtime->state = VTIME_IDLE;
797 else if (current->flags & PF_VCPU)
798 vtime->state = VTIME_GUEST;
800 vtime->state = VTIME_SYS;
801 vtime->starttime = sched_clock();
802 vtime->cpu = smp_processor_id();
803 write_seqcount_end(&vtime->seqcount);
806 void vtime_init_idle(struct task_struct *t, int cpu)
808 struct vtime *vtime = &t->vtime;
811 local_irq_save(flags);
812 write_seqcount_begin(&vtime->seqcount);
813 vtime->state = VTIME_IDLE;
814 vtime->starttime = sched_clock();
816 write_seqcount_end(&vtime->seqcount);
817 local_irq_restore(flags);
820 u64 task_gtime(struct task_struct *t)
822 struct vtime *vtime = &t->vtime;
826 if (!vtime_accounting_enabled())
830 seq = read_seqcount_begin(&vtime->seqcount);
833 if (vtime->state == VTIME_GUEST)
834 gtime += vtime->gtime + vtime_delta(vtime);
836 } while (read_seqcount_retry(&vtime->seqcount, seq));
842 * Fetch cputime raw values from fields of task_struct and
843 * add up the pending nohz execution time since the last
846 bool task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
848 struct vtime *vtime = &t->vtime;
853 if (!vtime_accounting_enabled()) {
861 seq = read_seqcount_begin(&vtime->seqcount);
866 /* Task is sleeping or idle, nothing to add */
867 if (vtime->state < VTIME_SYS)
871 delta = vtime_delta(vtime);
874 * Task runs either in user (including guest) or kernel space,
875 * add pending nohz time to the right place.
877 if (vtime->state == VTIME_SYS)
878 *stime += vtime->stime + delta;
880 *utime += vtime->utime + delta;
881 } while (read_seqcount_retry(&vtime->seqcount, seq));
886 static int vtime_state_fetch(struct vtime *vtime, int cpu)
888 int state = READ_ONCE(vtime->state);
891 * We raced against a context switch, fetch the
892 * kcpustat task again.
894 if (vtime->cpu != cpu && vtime->cpu != -1)
898 * Two possible things here:
899 * 1) We are seeing the scheduling out task (prev) or any past one.
900 * 2) We are seeing the scheduling in task (next) but it hasn't
901 * passed though vtime_task_switch() yet so the pending
902 * cputime of the prev task may not be flushed yet.
904 * Case 1) is ok but 2) is not. So wait for a safe VTIME state.
906 if (state == VTIME_INACTIVE)
912 static u64 kcpustat_user_vtime(struct vtime *vtime)
914 if (vtime->state == VTIME_USER)
915 return vtime->utime + vtime_delta(vtime);
916 else if (vtime->state == VTIME_GUEST)
917 return vtime->gtime + vtime_delta(vtime);
921 static int kcpustat_field_vtime(u64 *cpustat,
922 struct task_struct *tsk,
923 enum cpu_usage_stat usage,
926 struct vtime *vtime = &tsk->vtime;
932 seq = read_seqcount_begin(&vtime->seqcount);
934 state = vtime_state_fetch(vtime, cpu);
938 *val = cpustat[usage];
941 * Nice VS unnice cputime accounting may be inaccurate if
942 * the nice value has changed since the last vtime update.
943 * But proper fix would involve interrupting target on nice
944 * updates which is a no go on nohz_full (although the scheduler
945 * may still interrupt the target if rescheduling is needed...)
949 if (state == VTIME_SYS)
950 *val += vtime->stime + vtime_delta(vtime);
953 if (task_nice(tsk) <= 0)
954 *val += kcpustat_user_vtime(vtime);
957 if (task_nice(tsk) > 0)
958 *val += kcpustat_user_vtime(vtime);
961 if (state == VTIME_GUEST && task_nice(tsk) <= 0)
962 *val += vtime->gtime + vtime_delta(vtime);
964 case CPUTIME_GUEST_NICE:
965 if (state == VTIME_GUEST && task_nice(tsk) > 0)
966 *val += vtime->gtime + vtime_delta(vtime);
971 } while (read_seqcount_retry(&vtime->seqcount, seq));
976 u64 kcpustat_field(struct kernel_cpustat *kcpustat,
977 enum cpu_usage_stat usage, int cpu)
979 u64 *cpustat = kcpustat->cpustat;
980 u64 val = cpustat[usage];
984 if (!vtime_accounting_enabled_cpu(cpu))
990 struct task_struct *curr;
993 curr = rcu_dereference(rq->curr);
994 if (WARN_ON_ONCE(!curr)) {
996 return cpustat[usage];
999 err = kcpustat_field_vtime(cpustat, curr, usage, cpu, &val);
1008 EXPORT_SYMBOL_GPL(kcpustat_field);
1010 static int kcpustat_cpu_fetch_vtime(struct kernel_cpustat *dst,
1011 const struct kernel_cpustat *src,
1012 struct task_struct *tsk, int cpu)
1014 struct vtime *vtime = &tsk->vtime;
1022 seq = read_seqcount_begin(&vtime->seqcount);
1024 state = vtime_state_fetch(vtime, cpu);
1029 cpustat = dst->cpustat;
1031 /* Task is sleeping, dead or idle, nothing to add */
1032 if (state < VTIME_SYS)
1035 delta = vtime_delta(vtime);
1038 * Task runs either in user (including guest) or kernel space,
1039 * add pending nohz time to the right place.
1041 if (state == VTIME_SYS) {
1042 cpustat[CPUTIME_SYSTEM] += vtime->stime + delta;
1043 } else if (state == VTIME_USER) {
1044 if (task_nice(tsk) > 0)
1045 cpustat[CPUTIME_NICE] += vtime->utime + delta;
1047 cpustat[CPUTIME_USER] += vtime->utime + delta;
1049 WARN_ON_ONCE(state != VTIME_GUEST);
1050 if (task_nice(tsk) > 0) {
1051 cpustat[CPUTIME_GUEST_NICE] += vtime->gtime + delta;
1052 cpustat[CPUTIME_NICE] += vtime->gtime + delta;
1054 cpustat[CPUTIME_GUEST] += vtime->gtime + delta;
1055 cpustat[CPUTIME_USER] += vtime->gtime + delta;
1058 } while (read_seqcount_retry(&vtime->seqcount, seq));
1063 void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
1065 const struct kernel_cpustat *src = &kcpustat_cpu(cpu);
1069 if (!vtime_accounting_enabled_cpu(cpu)) {
1077 struct task_struct *curr;
1080 curr = rcu_dereference(rq->curr);
1081 if (WARN_ON_ONCE(!curr)) {
1087 err = kcpustat_cpu_fetch_vtime(dst, src, curr, cpu);
1096 EXPORT_SYMBOL_GPL(kcpustat_cpu_fetch);
1098 #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */