diff options
Diffstat (limited to 'kernel/sched/cputime.c')
| -rw-r--r-- | kernel/sched/cputime.c | 838 | 
1 files changed, 838 insertions, 0 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c new file mode 100644 index 00000000000..72fdf06ef86 --- /dev/null +++ b/kernel/sched/cputime.c @@ -0,0 +1,838 @@ +#include <linux/export.h> +#include <linux/sched.h> +#include <linux/tsacct_kern.h> +#include <linux/kernel_stat.h> +#include <linux/static_key.h> +#include <linux/context_tracking.h> +#include "sched.h" + + +#ifdef CONFIG_IRQ_TIME_ACCOUNTING + +/* + * There are no locks covering percpu hardirq/softirq time. + * They are only modified in vtime_account, on corresponding CPU + * with interrupts disabled. So, writes are safe. + * They are read and saved off onto struct rq in update_rq_clock(). + * This may result in other CPU reading this CPU's irq time and can + * race with irq/vtime_account on this CPU. We would either get old + * or new value with a side effect of accounting a slice of irq time to wrong + * task when irq is in progress while we read rq->clock. That is a worthy + * compromise in place of having locks on each irq in account_system_time. + */ +DEFINE_PER_CPU(u64, cpu_hardirq_time); +DEFINE_PER_CPU(u64, cpu_softirq_time); + +static DEFINE_PER_CPU(u64, irq_start_time); +static int sched_clock_irqtime; + +void enable_sched_clock_irqtime(void) +{ +	sched_clock_irqtime = 1; +} + +void disable_sched_clock_irqtime(void) +{ +	sched_clock_irqtime = 0; +} + +#ifndef CONFIG_64BIT +DEFINE_PER_CPU(seqcount_t, irq_time_seq); +#endif /* CONFIG_64BIT */ + +/* + * Called before incrementing preempt_count on {soft,}irq_enter + * and before decrementing preempt_count on {soft,}irq_exit. + */ +void irqtime_account_irq(struct task_struct *curr) +{ +	unsigned long flags; +	s64 delta; +	int cpu; + +	if (!sched_clock_irqtime) +		return; + +	local_irq_save(flags); + +	cpu = smp_processor_id(); +	delta = sched_clock_cpu(cpu) - __this_cpu_read(irq_start_time); +	__this_cpu_add(irq_start_time, delta); + +	irq_time_write_begin(); +	/* +	 * We do not account for softirq time from ksoftirqd here. +	 * We want to continue accounting softirq time to ksoftirqd thread +	 * in that case, so as not to confuse scheduler with a special task +	 * that do not consume any time, but still wants to run. +	 */ +	if (hardirq_count()) +		__this_cpu_add(cpu_hardirq_time, delta); +	else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) +		__this_cpu_add(cpu_softirq_time, delta); + +	irq_time_write_end(); +	local_irq_restore(flags); +} +EXPORT_SYMBOL_GPL(irqtime_account_irq); + +static int irqtime_account_hi_update(void) +{ +	u64 *cpustat = kcpustat_this_cpu->cpustat; +	unsigned long flags; +	u64 latest_ns; +	int ret = 0; + +	local_irq_save(flags); +	latest_ns = this_cpu_read(cpu_hardirq_time); +	if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_IRQ]) +		ret = 1; +	local_irq_restore(flags); +	return ret; +} + +static int irqtime_account_si_update(void) +{ +	u64 *cpustat = kcpustat_this_cpu->cpustat; +	unsigned long flags; +	u64 latest_ns; +	int ret = 0; + +	local_irq_save(flags); +	latest_ns = this_cpu_read(cpu_softirq_time); +	if (nsecs_to_cputime64(latest_ns) > cpustat[CPUTIME_SOFTIRQ]) +		ret = 1; +	local_irq_restore(flags); +	return ret; +} + +#else /* CONFIG_IRQ_TIME_ACCOUNTING */ + +#define sched_clock_irqtime	(0) + +#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */ + +static inline void task_group_account_field(struct task_struct *p, int index, +					    u64 tmp) +{ +	/* +	 * Since all updates are sure to touch the root cgroup, we +	 * get ourselves ahead and touch it first. If the root cgroup +	 * is the only cgroup, then nothing else should be necessary. +	 * +	 */ +	__this_cpu_add(kernel_cpustat.cpustat[index], tmp); + +	cpuacct_account_field(p, index, tmp); +} + +/* + * Account user cpu time to a process. + * @p: the process that the cpu time gets accounted to + * @cputime: the cpu time spent in user space since the last update + * @cputime_scaled: cputime scaled by cpu frequency + */ +void account_user_time(struct task_struct *p, cputime_t cputime, +		       cputime_t cputime_scaled) +{ +	int index; + +	/* Add user time to process. */ +	p->utime += cputime; +	p->utimescaled += cputime_scaled; +	account_group_user_time(p, cputime); + +	index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER; + +	/* Add user time to cpustat. */ +	task_group_account_field(p, index, (__force u64) cputime); + +	/* Account for user time used */ +	acct_account_cputime(p); +} + +/* + * Account guest cpu time to a process. + * @p: the process that the cpu time gets accounted to + * @cputime: the cpu time spent in virtual machine since the last update + * @cputime_scaled: cputime scaled by cpu frequency + */ +static void account_guest_time(struct task_struct *p, cputime_t cputime, +			       cputime_t cputime_scaled) +{ +	u64 *cpustat = kcpustat_this_cpu->cpustat; + +	/* Add guest time to process. */ +	p->utime += cputime; +	p->utimescaled += cputime_scaled; +	account_group_user_time(p, cputime); +	p->gtime += cputime; + +	/* Add guest time to cpustat. */ +	if (task_nice(p) > 0) { +		cpustat[CPUTIME_NICE] += (__force u64) cputime; +		cpustat[CPUTIME_GUEST_NICE] += (__force u64) cputime; +	} else { +		cpustat[CPUTIME_USER] += (__force u64) cputime; +		cpustat[CPUTIME_GUEST] += (__force u64) cputime; +	} +} + +/* + * Account system cpu time to a process and desired cpustat field + * @p: the process that the cpu time gets accounted to + * @cputime: the cpu time spent in kernel space since the last update + * @cputime_scaled: cputime scaled by cpu frequency + * @target_cputime64: pointer to cpustat field that has to be updated + */ +static inline +void __account_system_time(struct task_struct *p, cputime_t cputime, +			cputime_t cputime_scaled, int index) +{ +	/* Add system time to process. */ +	p->stime += cputime; +	p->stimescaled += cputime_scaled; +	account_group_system_time(p, cputime); + +	/* Add system time to cpustat. */ +	task_group_account_field(p, index, (__force u64) cputime); + +	/* Account for system time used */ +	acct_account_cputime(p); +} + +/* + * Account system cpu time to a process. + * @p: the process that the cpu time gets accounted to + * @hardirq_offset: the offset to subtract from hardirq_count() + * @cputime: the cpu time spent in kernel space since the last update + * @cputime_scaled: cputime scaled by cpu frequency + */ +void account_system_time(struct task_struct *p, int hardirq_offset, +			 cputime_t cputime, cputime_t cputime_scaled) +{ +	int index; + +	if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { +		account_guest_time(p, cputime, cputime_scaled); +		return; +	} + +	if (hardirq_count() - hardirq_offset) +		index = CPUTIME_IRQ; +	else if (in_serving_softirq()) +		index = CPUTIME_SOFTIRQ; +	else +		index = CPUTIME_SYSTEM; + +	__account_system_time(p, cputime, cputime_scaled, index); +} + +/* + * Account for involuntary wait time. + * @cputime: the cpu time spent in involuntary wait + */ +void account_steal_time(cputime_t cputime) +{ +	u64 *cpustat = kcpustat_this_cpu->cpustat; + +	cpustat[CPUTIME_STEAL] += (__force u64) cputime; +} + +/* + * Account for idle time. + * @cputime: the cpu time spent in idle wait + */ +void account_idle_time(cputime_t cputime) +{ +	u64 *cpustat = kcpustat_this_cpu->cpustat; +	struct rq *rq = this_rq(); + +	if (atomic_read(&rq->nr_iowait) > 0) +		cpustat[CPUTIME_IOWAIT] += (__force u64) cputime; +	else +		cpustat[CPUTIME_IDLE] += (__force u64) cputime; +} + +static __always_inline bool steal_account_process_tick(void) +{ +#ifdef CONFIG_PARAVIRT +	if (static_key_false(¶virt_steal_enabled)) { +		u64 steal; +		cputime_t steal_ct; + +		steal = paravirt_steal_clock(smp_processor_id()); +		steal -= this_rq()->prev_steal_time; + +		/* +		 * cputime_t may be less precise than nsecs (eg: if it's +		 * based on jiffies). Lets cast the result to cputime +		 * granularity and account the rest on the next rounds. +		 */ +		steal_ct = nsecs_to_cputime(steal); +		this_rq()->prev_steal_time += cputime_to_nsecs(steal_ct); + +		account_steal_time(steal_ct); +		return steal_ct; +	} +#endif +	return false; +} + +/* + * Accumulate raw cputime values of dead tasks (sig->[us]time) and live + * tasks (sum on group iteration) belonging to @tsk's group. + */ +void thread_group_cputime(struct task_struct *tsk, struct task_cputime *times) +{ +	struct signal_struct *sig = tsk->signal; +	cputime_t utime, stime; +	struct task_struct *t; + +	times->utime = sig->utime; +	times->stime = sig->stime; +	times->sum_exec_runtime = sig->sum_sched_runtime; + +	rcu_read_lock(); +	/* make sure we can trust tsk->thread_group list */ +	if (!likely(pid_alive(tsk))) +		goto out; + +	t = tsk; +	do { +		task_cputime(t, &utime, &stime); +		times->utime += utime; +		times->stime += stime; +		times->sum_exec_runtime += task_sched_runtime(t); +	} while_each_thread(tsk, t); +out: +	rcu_read_unlock(); +} + +#ifdef CONFIG_IRQ_TIME_ACCOUNTING +/* + * Account a tick to a process and cpustat + * @p: the process that the cpu time gets accounted to + * @user_tick: is the tick from userspace + * @rq: the pointer to rq + * + * Tick demultiplexing follows the order + * - pending hardirq update + * - pending softirq update + * - user_time + * - idle_time + * - system time + *   - check for guest_time + *   - else account as system_time + * + * Check for hardirq is done both for system and user time as there is + * no timer going off while we are on hardirq and hence we may never get an + * opportunity to update it solely in system time. + * p->stime and friends are only updated on system time and not on irq + * softirq as those do not count in task exec_runtime any more. + */ +static void irqtime_account_process_tick(struct task_struct *p, int user_tick, +					 struct rq *rq, int ticks) +{ +	cputime_t scaled = cputime_to_scaled(cputime_one_jiffy); +	u64 cputime = (__force u64) cputime_one_jiffy; +	u64 *cpustat = kcpustat_this_cpu->cpustat; + +	if (steal_account_process_tick()) +		return; + +	cputime *= ticks; +	scaled *= ticks; + +	if (irqtime_account_hi_update()) { +		cpustat[CPUTIME_IRQ] += cputime; +	} else if (irqtime_account_si_update()) { +		cpustat[CPUTIME_SOFTIRQ] += cputime; +	} else if (this_cpu_ksoftirqd() == p) { +		/* +		 * ksoftirqd time do not get accounted in cpu_softirq_time. +		 * So, we have to handle it separately here. +		 * Also, p->stime needs to be updated for ksoftirqd. +		 */ +		__account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ); +	} else if (user_tick) { +		account_user_time(p, cputime, scaled); +	} else if (p == rq->idle) { +		account_idle_time(cputime); +	} else if (p->flags & PF_VCPU) { /* System time or guest time */ +		account_guest_time(p, cputime, scaled); +	} else { +		__account_system_time(p, cputime, scaled,	CPUTIME_SYSTEM); +	} +} + +static void irqtime_account_idle_ticks(int ticks) +{ +	struct rq *rq = this_rq(); + +	irqtime_account_process_tick(current, 0, rq, ticks); +} +#else /* CONFIG_IRQ_TIME_ACCOUNTING */ +static inline void irqtime_account_idle_ticks(int ticks) {} +static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick, +						struct rq *rq, int nr_ticks) {} +#endif /* CONFIG_IRQ_TIME_ACCOUNTING */ + +/* + * Use precise platform statistics if available: + */ +#ifdef CONFIG_VIRT_CPU_ACCOUNTING + +#ifndef __ARCH_HAS_VTIME_TASK_SWITCH +void vtime_common_task_switch(struct task_struct *prev) +{ +	if (is_idle_task(prev)) +		vtime_account_idle(prev); +	else +		vtime_account_system(prev); + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE +	vtime_account_user(prev); +#endif +	arch_vtime_task_switch(prev); +} +#endif + +/* + * Archs that account the whole time spent in the idle task + * (outside irq) as idle time can rely on this and just implement + * vtime_account_system() and vtime_account_idle(). Archs that + * have other meaning of the idle time (s390 only includes the + * time spent by the CPU when it's in low power mode) must override + * vtime_account(). + */ +#ifndef __ARCH_HAS_VTIME_ACCOUNT +void vtime_common_account_irq_enter(struct task_struct *tsk) +{ +	if (!in_interrupt()) { +		/* +		 * If we interrupted user, context_tracking_in_user() +		 * is 1 because the context tracking don't hook +		 * on irq entry/exit. This way we know if +		 * we need to flush user time on kernel entry. +		 */ +		if (context_tracking_in_user()) { +			vtime_account_user(tsk); +			return; +		} + +		if (is_idle_task(tsk)) { +			vtime_account_idle(tsk); +			return; +		} +	} +	vtime_account_system(tsk); +} +EXPORT_SYMBOL_GPL(vtime_common_account_irq_enter); +#endif /* __ARCH_HAS_VTIME_ACCOUNT */ +#endif /* CONFIG_VIRT_CPU_ACCOUNTING */ + + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE +void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) +{ +	*ut = p->utime; +	*st = p->stime; +} + +void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) +{ +	struct task_cputime cputime; + +	thread_group_cputime(p, &cputime); + +	*ut = cputime.utime; +	*st = cputime.stime; +} +#else /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ +/* + * Account a single tick of cpu time. + * @p: the process that the cpu time gets accounted to + * @user_tick: indicates if the tick is a user or a system tick + */ +void account_process_tick(struct task_struct *p, int user_tick) +{ +	cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); +	struct rq *rq = this_rq(); + +	if (vtime_accounting_enabled()) +		return; + +	if (sched_clock_irqtime) { +		irqtime_account_process_tick(p, user_tick, rq, 1); +		return; +	} + +	if (steal_account_process_tick()) +		return; + +	if (user_tick) +		account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); +	else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) +		account_system_time(p, HARDIRQ_OFFSET, cputime_one_jiffy, +				    one_jiffy_scaled); +	else +		account_idle_time(cputime_one_jiffy); +} + +/* + * Account multiple ticks of steal time. + * @p: the process from which the cpu time has been stolen + * @ticks: number of stolen ticks + */ +void account_steal_ticks(unsigned long ticks) +{ +	account_steal_time(jiffies_to_cputime(ticks)); +} + +/* + * Account multiple ticks of idle time. + * @ticks: number of stolen ticks + */ +void account_idle_ticks(unsigned long ticks) +{ + +	if (sched_clock_irqtime) { +		irqtime_account_idle_ticks(ticks); +		return; +	} + +	account_idle_time(jiffies_to_cputime(ticks)); +} + +/* + * Perform (stime * rtime) / total, but avoid multiplication overflow by + * loosing precision when the numbers are big. + */ +static cputime_t scale_stime(u64 stime, u64 rtime, u64 total) +{ +	u64 scaled; + +	for (;;) { +		/* Make sure "rtime" is the bigger of stime/rtime */ +		if (stime > rtime) +			swap(rtime, stime); + +		/* Make sure 'total' fits in 32 bits */ +		if (total >> 32) +			goto drop_precision; + +		/* Does rtime (and thus stime) fit in 32 bits? */ +		if (!(rtime >> 32)) +			break; + +		/* Can we just balance rtime/stime rather than dropping bits? */ +		if (stime >> 31) +			goto drop_precision; + +		/* We can grow stime and shrink rtime and try to make them both fit */ +		stime <<= 1; +		rtime >>= 1; +		continue; + +drop_precision: +		/* We drop from rtime, it has more bits than stime */ +		rtime >>= 1; +		total >>= 1; +	} + +	/* +	 * Make sure gcc understands that this is a 32x32->64 multiply, +	 * followed by a 64/32->64 divide. +	 */ +	scaled = div_u64((u64) (u32) stime * (u64) (u32) rtime, (u32)total); +	return (__force cputime_t) scaled; +} + +/* + * Adjust tick based cputime random precision against scheduler + * runtime accounting. + */ +static void cputime_adjust(struct task_cputime *curr, +			   struct cputime *prev, +			   cputime_t *ut, cputime_t *st) +{ +	cputime_t rtime, stime, utime; + +	/* +	 * Tick based cputime accounting depend on random scheduling +	 * timeslices of a task to be interrupted or not by the timer. +	 * Depending on these circumstances, the number of these interrupts +	 * may be over or under-optimistic, matching the real user and system +	 * cputime with a variable precision. +	 * +	 * Fix this by scaling these tick based values against the total +	 * runtime accounted by the CFS scheduler. +	 */ +	rtime = nsecs_to_cputime(curr->sum_exec_runtime); + +	/* +	 * Update userspace visible utime/stime values only if actual execution +	 * time is bigger than already exported. Note that can happen, that we +	 * provided bigger values due to scaling inaccuracy on big numbers. +	 */ +	if (prev->stime + prev->utime >= rtime) +		goto out; + +	stime = curr->stime; +	utime = curr->utime; + +	if (utime == 0) { +		stime = rtime; +	} else if (stime == 0) { +		utime = rtime; +	} else { +		cputime_t total = stime + utime; + +		stime = scale_stime((__force u64)stime, +				    (__force u64)rtime, (__force u64)total); +		utime = rtime - stime; +	} + +	/* +	 * If the tick based count grows faster than the scheduler one, +	 * the result of the scaling may go backward. +	 * Let's enforce monotonicity. +	 */ +	prev->stime = max(prev->stime, stime); +	prev->utime = max(prev->utime, utime); + +out: +	*ut = prev->utime; +	*st = prev->stime; +} + +void task_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) +{ +	struct task_cputime cputime = { +		.sum_exec_runtime = p->se.sum_exec_runtime, +	}; + +	task_cputime(p, &cputime.utime, &cputime.stime); +	cputime_adjust(&cputime, &p->prev_cputime, ut, st); +} + +/* + * Must be called with siglock held. + */ +void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime_t *st) +{ +	struct task_cputime cputime; + +	thread_group_cputime(p, &cputime); +	cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st); +} +#endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ + +#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN +static unsigned long long vtime_delta(struct task_struct *tsk) +{ +	unsigned long long clock; + +	clock = local_clock(); +	if (clock < tsk->vtime_snap) +		return 0; + +	return clock - tsk->vtime_snap; +} + +static cputime_t get_vtime_delta(struct task_struct *tsk) +{ +	unsigned long long delta = vtime_delta(tsk); + +	WARN_ON_ONCE(tsk->vtime_snap_whence == VTIME_SLEEPING); +	tsk->vtime_snap += delta; + +	/* CHECKME: always safe to convert nsecs to cputime? */ +	return nsecs_to_cputime(delta); +} + +static void __vtime_account_system(struct task_struct *tsk) +{ +	cputime_t delta_cpu = get_vtime_delta(tsk); + +	account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu)); +} + +void vtime_account_system(struct task_struct *tsk) +{ +	write_seqlock(&tsk->vtime_seqlock); +	__vtime_account_system(tsk); +	write_sequnlock(&tsk->vtime_seqlock); +} + +void vtime_gen_account_irq_exit(struct task_struct *tsk) +{ +	write_seqlock(&tsk->vtime_seqlock); +	__vtime_account_system(tsk); +	if (context_tracking_in_user()) +		tsk->vtime_snap_whence = VTIME_USER; +	write_sequnlock(&tsk->vtime_seqlock); +} + +void vtime_account_user(struct task_struct *tsk) +{ +	cputime_t delta_cpu; + +	write_seqlock(&tsk->vtime_seqlock); +	delta_cpu = get_vtime_delta(tsk); +	tsk->vtime_snap_whence = VTIME_SYS; +	account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu)); +	write_sequnlock(&tsk->vtime_seqlock); +} + +void vtime_user_enter(struct task_struct *tsk) +{ +	write_seqlock(&tsk->vtime_seqlock); +	__vtime_account_system(tsk); +	tsk->vtime_snap_whence = VTIME_USER; +	write_sequnlock(&tsk->vtime_seqlock); +} + +void vtime_guest_enter(struct task_struct *tsk) +{ +	/* +	 * The flags must be updated under the lock with +	 * the vtime_snap flush and update. +	 * That enforces a right ordering and update sequence +	 * synchronization against the reader (task_gtime()) +	 * that can thus safely catch up with a tickless delta. +	 */ +	write_seqlock(&tsk->vtime_seqlock); +	__vtime_account_system(tsk); +	current->flags |= PF_VCPU; +	write_sequnlock(&tsk->vtime_seqlock); +} +EXPORT_SYMBOL_GPL(vtime_guest_enter); + +void vtime_guest_exit(struct task_struct *tsk) +{ +	write_seqlock(&tsk->vtime_seqlock); +	__vtime_account_system(tsk); +	current->flags &= ~PF_VCPU; +	write_sequnlock(&tsk->vtime_seqlock); +} +EXPORT_SYMBOL_GPL(vtime_guest_exit); + +void vtime_account_idle(struct task_struct *tsk) +{ +	cputime_t delta_cpu = get_vtime_delta(tsk); + +	account_idle_time(delta_cpu); +} + +void arch_vtime_task_switch(struct task_struct *prev) +{ +	write_seqlock(&prev->vtime_seqlock); +	prev->vtime_snap_whence = VTIME_SLEEPING; +	write_sequnlock(&prev->vtime_seqlock); + +	write_seqlock(¤t->vtime_seqlock); +	current->vtime_snap_whence = VTIME_SYS; +	current->vtime_snap = sched_clock_cpu(smp_processor_id()); +	write_sequnlock(¤t->vtime_seqlock); +} + +void vtime_init_idle(struct task_struct *t, int cpu) +{ +	unsigned long flags; + +	write_seqlock_irqsave(&t->vtime_seqlock, flags); +	t->vtime_snap_whence = VTIME_SYS; +	t->vtime_snap = sched_clock_cpu(cpu); +	write_sequnlock_irqrestore(&t->vtime_seqlock, flags); +} + +cputime_t task_gtime(struct task_struct *t) +{ +	unsigned int seq; +	cputime_t gtime; + +	do { +		seq = read_seqbegin(&t->vtime_seqlock); + +		gtime = t->gtime; +		if (t->flags & PF_VCPU) +			gtime += vtime_delta(t); + +	} while (read_seqretry(&t->vtime_seqlock, seq)); + +	return gtime; +} + +/* + * Fetch cputime raw values from fields of task_struct and + * add up the pending nohz execution time since the last + * cputime snapshot. + */ +static void +fetch_task_cputime(struct task_struct *t, +		   cputime_t *u_dst, cputime_t *s_dst, +		   cputime_t *u_src, cputime_t *s_src, +		   cputime_t *udelta, cputime_t *sdelta) +{ +	unsigned int seq; +	unsigned long long delta; + +	do { +		*udelta = 0; +		*sdelta = 0; + +		seq = read_seqbegin(&t->vtime_seqlock); + +		if (u_dst) +			*u_dst = *u_src; +		if (s_dst) +			*s_dst = *s_src; + +		/* Task is sleeping, nothing to add */ +		if (t->vtime_snap_whence == VTIME_SLEEPING || +		    is_idle_task(t)) +			continue; + +		delta = vtime_delta(t); + +		/* +		 * Task runs either in user or kernel space, add pending nohz time to +		 * the right place. +		 */ +		if (t->vtime_snap_whence == VTIME_USER || t->flags & PF_VCPU) { +			*udelta = delta; +		} else { +			if (t->vtime_snap_whence == VTIME_SYS) +				*sdelta = delta; +		} +	} while (read_seqretry(&t->vtime_seqlock, seq)); +} + + +void task_cputime(struct task_struct *t, cputime_t *utime, cputime_t *stime) +{ +	cputime_t udelta, sdelta; + +	fetch_task_cputime(t, utime, stime, &t->utime, +			   &t->stime, &udelta, &sdelta); +	if (utime) +		*utime += udelta; +	if (stime) +		*stime += sdelta; +} + +void task_cputime_scaled(struct task_struct *t, +			 cputime_t *utimescaled, cputime_t *stimescaled) +{ +	cputime_t udelta, sdelta; + +	fetch_task_cputime(t, utimescaled, stimescaled, +			   &t->utimescaled, &t->stimescaled, &udelta, &sdelta); +	if (utimescaled) +		*utimescaled += cputime_to_scaled(udelta); +	if (stimescaled) +		*stimescaled += cputime_to_scaled(sdelta); +} +#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */  | 
