| // SPDX-License-Identifier: GPL-2.0-only |
| /* |
| * Simple CPU accounting cgroup controller |
| */ |
| #include <linux/cpufreq_times.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(struct irqtime, cpu_irqtime); |
| |
| 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; |
| } |
| |
| static void irqtime_account_delta(struct irqtime *irqtime, u64 delta, |
| enum cpu_usage_stat idx) |
| { |
| u64 *cpustat = kcpustat_this_cpu->cpustat; |
| |
| u64_stats_update_begin(&irqtime->sync); |
| cpustat[idx] += delta; |
| irqtime->total += delta; |
| irqtime->tick_delta += delta; |
| u64_stats_update_end(&irqtime->sync); |
| } |
| |
| /* |
| * 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) |
| { |
| struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime); |
| s64 delta; |
| int cpu; |
| |
| if (!sched_clock_irqtime) |
| return; |
| |
| cpu = smp_processor_id(); |
| delta = sched_clock_cpu(cpu) - irqtime->irq_start_time; |
| irqtime->irq_start_time += delta; |
| |
| /* |
| * 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()) |
| irqtime_account_delta(irqtime, delta, CPUTIME_IRQ); |
| else if (in_serving_softirq() && curr != this_cpu_ksoftirqd()) |
| irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ); |
| } |
| EXPORT_SYMBOL_GPL(irqtime_account_irq); |
| |
| static u64 irqtime_tick_accounted(u64 maxtime) |
| { |
| struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime); |
| u64 delta; |
| |
| delta = min(irqtime->tick_delta, maxtime); |
| irqtime->tick_delta -= delta; |
| |
| return delta; |
| } |
| |
| #else /* CONFIG_IRQ_TIME_ACCOUNTING */ |
| |
| #define sched_clock_irqtime (0) |
| |
| static u64 irqtime_tick_accounted(u64 dummy) |
| { |
| return 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); |
| |
| cgroup_account_cputime_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 |
| */ |
| void account_user_time(struct task_struct *p, u64 cputime) |
| { |
| int index; |
| |
| /* Add user time to process. */ |
| p->utime += cputime; |
| 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, cputime); |
| |
| /* Account for user time used */ |
| acct_account_cputime(p); |
| |
| /* Account power usage for user time */ |
| cpufreq_acct_update_power(p, cputime); |
| } |
| |
| /* |
| * 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 |
| */ |
| void account_guest_time(struct task_struct *p, u64 cputime) |
| { |
| u64 *cpustat = kcpustat_this_cpu->cpustat; |
| |
| /* Add guest time to process. */ |
| p->utime += cputime; |
| account_group_user_time(p, cputime); |
| p->gtime += cputime; |
| |
| /* Add guest time to cpustat. */ |
| if (task_nice(p) > 0) { |
| cpustat[CPUTIME_NICE] += cputime; |
| cpustat[CPUTIME_GUEST_NICE] += cputime; |
| } else { |
| cpustat[CPUTIME_USER] += cputime; |
| cpustat[CPUTIME_GUEST] += 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 |
| * @index: pointer to cpustat field that has to be updated |
| */ |
| void account_system_index_time(struct task_struct *p, |
| u64 cputime, enum cpu_usage_stat index) |
| { |
| /* Add system time to process. */ |
| p->stime += cputime; |
| account_group_system_time(p, cputime); |
| |
| /* Add system time to cpustat. */ |
| task_group_account_field(p, index, cputime); |
| |
| /* Account for system time used */ |
| acct_account_cputime(p); |
| |
| /* Account power usage for system time */ |
| cpufreq_acct_update_power(p, cputime); |
| } |
| |
| /* |
| * 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 |
| */ |
| void account_system_time(struct task_struct *p, int hardirq_offset, u64 cputime) |
| { |
| int index; |
| |
| if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
| account_guest_time(p, cputime); |
| return; |
| } |
| |
| if (hardirq_count() - hardirq_offset) |
| index = CPUTIME_IRQ; |
| else if (in_serving_softirq()) |
| index = CPUTIME_SOFTIRQ; |
| else |
| index = CPUTIME_SYSTEM; |
| |
| account_system_index_time(p, cputime, index); |
| } |
| |
| /* |
| * Account for involuntary wait time. |
| * @cputime: the CPU time spent in involuntary wait |
| */ |
| void account_steal_time(u64 cputime) |
| { |
| u64 *cpustat = kcpustat_this_cpu->cpustat; |
| |
| cpustat[CPUTIME_STEAL] += cputime; |
| } |
| |
| /* |
| * Account for idle time. |
| * @cputime: the CPU time spent in idle wait |
| */ |
| void account_idle_time(u64 cputime) |
| { |
| u64 *cpustat = kcpustat_this_cpu->cpustat; |
| struct rq *rq = this_rq(); |
| |
| if (atomic_read(&rq->nr_iowait) > 0) |
| cpustat[CPUTIME_IOWAIT] += cputime; |
| else |
| cpustat[CPUTIME_IDLE] += cputime; |
| } |
| |
| /* |
| * When a guest is interrupted for a longer amount of time, missed clock |
| * ticks are not redelivered later. Due to that, this function may on |
| * occasion account more time than the calling functions think elapsed. |
| */ |
| static __always_inline u64 steal_account_process_time(u64 maxtime) |
| { |
| #ifdef CONFIG_PARAVIRT |
| if (static_key_false(¶virt_steal_enabled)) { |
| u64 steal; |
| |
| steal = paravirt_steal_clock(smp_processor_id()); |
| steal -= this_rq()->prev_steal_time; |
| steal = min(steal, maxtime); |
| account_steal_time(steal); |
| this_rq()->prev_steal_time += steal; |
| |
| return steal; |
| } |
| #endif |
| return 0; |
| } |
| |
| /* |
| * Account how much elapsed time was spent in steal, irq, or softirq time. |
| */ |
| static inline u64 account_other_time(u64 max) |
| { |
| u64 accounted; |
| |
| lockdep_assert_irqs_disabled(); |
| |
| accounted = steal_account_process_time(max); |
| |
| if (accounted < max) |
| accounted += irqtime_tick_accounted(max - accounted); |
| |
| return accounted; |
| } |
| |
| #ifdef CONFIG_64BIT |
| static inline u64 read_sum_exec_runtime(struct task_struct *t) |
| { |
| return t->se.sum_exec_runtime; |
| } |
| #else |
| static u64 read_sum_exec_runtime(struct task_struct *t) |
| { |
| u64 ns; |
| struct rq_flags rf; |
| struct rq *rq; |
| |
| rq = task_rq_lock(t, &rf); |
| ns = t->se.sum_exec_runtime; |
| task_rq_unlock(rq, t, &rf); |
| |
| return ns; |
| } |
| #endif |
| |
| /* |
| * 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; |
| u64 utime, stime; |
| struct task_struct *t; |
| unsigned int seq, nextseq; |
| unsigned long flags; |
| |
| /* |
| * Update current task runtime to account pending time since last |
| * scheduler action or thread_group_cputime() call. This thread group |
| * might have other running tasks on different CPUs, but updating |
| * their runtime can affect syscall performance, so we skip account |
| * those pending times and rely only on values updated on tick or |
| * other scheduler action. |
| */ |
| if (same_thread_group(current, tsk)) |
| (void) task_sched_runtime(current); |
| |
| rcu_read_lock(); |
| /* Attempt a lockless read on the first round. */ |
| nextseq = 0; |
| do { |
| seq = nextseq; |
| flags = read_seqbegin_or_lock_irqsave(&sig->stats_lock, &seq); |
| times->utime = sig->utime; |
| times->stime = sig->stime; |
| times->sum_exec_runtime = sig->sum_sched_runtime; |
| |
| for_each_thread(tsk, t) { |
| task_cputime(t, &utime, &stime); |
| times->utime += utime; |
| times->stime += stime; |
| times->sum_exec_runtime += read_sum_exec_runtime(t); |
| } |
| /* If lockless access failed, take the lock. */ |
| nextseq = 1; |
| } while (need_seqretry(&sig->stats_lock, seq)); |
| done_seqretry_irqrestore(&sig->stats_lock, seq, flags); |
| 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) |
| { |
| u64 other, cputime = TICK_NSEC * ticks; |
| |
| /* |
| * When returning from idle, many ticks can get accounted at |
| * once, including some ticks of steal, irq, and softirq time. |
| * Subtract those ticks from the amount of time accounted to |
| * idle, or potentially user or system time. Due to rounding, |
| * other time can exceed ticks occasionally. |
| */ |
| other = account_other_time(ULONG_MAX); |
| if (other >= cputime) |
| return; |
| |
| cputime -= other; |
| |
| 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_index_time(p, cputime, CPUTIME_SOFTIRQ); |
| } else if (user_tick) { |
| account_user_time(p, cputime); |
| } 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); |
| } else { |
| account_system_index_time(p, cputime, 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); |
| |
| vtime_flush(prev); |
| arch_vtime_task_switch(prev); |
| } |
| # endif |
| #endif /* CONFIG_VIRT_CPU_ACCOUNTING */ |
| |
| |
| #ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE |
| /* |
| * 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_account_irq_enter(struct task_struct *tsk) |
| { |
| if (!in_interrupt() && is_idle_task(tsk)) |
| vtime_account_idle(tsk); |
| else |
| vtime_account_system(tsk); |
| } |
| EXPORT_SYMBOL_GPL(vtime_account_irq_enter); |
| #endif /* __ARCH_HAS_VTIME_ACCOUNT */ |
| |
| void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, |
| u64 *ut, u64 *st) |
| { |
| *ut = curr->utime; |
| *st = curr->stime; |
| } |
| |
| void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) |
| { |
| *ut = p->utime; |
| *st = p->stime; |
| } |
| EXPORT_SYMBOL_GPL(task_cputime_adjusted); |
| |
| void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) |
| { |
| struct task_cputime cputime; |
| |
| thread_group_cputime(p, &cputime); |
| |
| *ut = cputime.utime; |
| *st = cputime.stime; |
| } |
| EXPORT_SYMBOL_GPL(thread_group_cputime_adjusted); |
| |
| #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) |
| { |
| u64 cputime, steal; |
| struct rq *rq = this_rq(); |
| |
| if (vtime_accounting_cpu_enabled()) |
| return; |
| |
| if (sched_clock_irqtime) { |
| irqtime_account_process_tick(p, user_tick, rq, 1); |
| return; |
| } |
| |
| cputime = TICK_NSEC; |
| steal = steal_account_process_time(ULONG_MAX); |
| |
| if (steal >= cputime) |
| return; |
| |
| cputime -= steal; |
| |
| if (user_tick) |
| account_user_time(p, cputime); |
| else if ((p != rq->idle) || (irq_count() != HARDIRQ_OFFSET)) |
| account_system_time(p, HARDIRQ_OFFSET, cputime); |
| else |
| account_idle_time(cputime); |
| } |
| |
| /* |
| * Account multiple ticks of idle time. |
| * @ticks: number of stolen ticks |
| */ |
| void account_idle_ticks(unsigned long ticks) |
| { |
| u64 cputime, steal; |
| |
| if (sched_clock_irqtime) { |
| irqtime_account_idle_ticks(ticks); |
| return; |
| } |
| |
| cputime = ticks * TICK_NSEC; |
| steal = steal_account_process_time(ULONG_MAX); |
| |
| if (steal >= cputime) |
| return; |
| |
| cputime -= steal; |
| account_idle_time(cputime); |
| } |
| |
| /* |
| * Perform (stime * rtime) / total, but avoid multiplication overflow by |
| * losing precision when the numbers are big. |
| */ |
| static u64 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 scaled; |
| } |
| |
| /* |
| * Adjust tick based cputime random precision against scheduler runtime |
| * accounting. |
| * |
| * 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. |
| * |
| * This code provides the following guarantees: |
| * |
| * stime + utime == rtime |
| * stime_i+1 >= stime_i, utime_i+1 >= utime_i |
| * |
| * Assuming that rtime_i+1 >= rtime_i. |
| */ |
| void cputime_adjust(struct task_cputime *curr, struct prev_cputime *prev, |
| u64 *ut, u64 *st) |
| { |
| u64 rtime, stime, utime; |
| unsigned long flags; |
| |
| /* Serialize concurrent callers such that we can honour our guarantees */ |
| raw_spin_lock_irqsave(&prev->lock, flags); |
| rtime = curr->sum_exec_runtime; |
| |
| /* |
| * This is possible under two circumstances: |
| * - rtime isn't monotonic after all (a bug); |
| * - we got reordered by the lock. |
| * |
| * In both cases this acts as a filter such that the rest of the code |
| * can assume it is monotonic regardless of anything else. |
| */ |
| if (prev->stime + prev->utime >= rtime) |
| goto out; |
| |
| stime = curr->stime; |
| utime = curr->utime; |
| |
| /* |
| * If either stime or utime are 0, assume all runtime is userspace. |
| * Once a task gets some ticks, the monotonicy code at 'update:' |
| * will ensure things converge to the observed ratio. |
| */ |
| if (stime == 0) { |
| utime = rtime; |
| goto update; |
| } |
| |
| if (utime == 0) { |
| stime = rtime; |
| goto update; |
| } |
| |
| stime = scale_stime(stime, rtime, stime + utime); |
| |
| update: |
| /* |
| * Make sure stime doesn't go backwards; this preserves monotonicity |
| * for utime because rtime is monotonic. |
| * |
| * utime_i+1 = rtime_i+1 - stime_i |
| * = rtime_i+1 - (rtime_i - utime_i) |
| * = (rtime_i+1 - rtime_i) + utime_i |
| * >= utime_i |
| */ |
| if (stime < prev->stime) |
| stime = prev->stime; |
| utime = rtime - stime; |
| |
| /* |
| * Make sure utime doesn't go backwards; this still preserves |
| * monotonicity for stime, analogous argument to above. |
| */ |
| if (utime < prev->utime) { |
| utime = prev->utime; |
| stime = rtime - utime; |
| } |
| |
| prev->stime = stime; |
| prev->utime = utime; |
| out: |
| *ut = prev->utime; |
| *st = prev->stime; |
| raw_spin_unlock_irqrestore(&prev->lock, flags); |
| } |
| |
| void task_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *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); |
| } |
| EXPORT_SYMBOL_GPL(task_cputime_adjusted); |
| |
| void thread_group_cputime_adjusted(struct task_struct *p, u64 *ut, u64 *st) |
| { |
| struct task_cputime cputime; |
| |
| thread_group_cputime(p, &cputime); |
| cputime_adjust(&cputime, &p->signal->prev_cputime, ut, st); |
| } |
| EXPORT_SYMBOL_GPL(thread_group_cputime_adjusted); |
| |
| #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ |
| |
| #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN |
| static u64 vtime_delta(struct vtime *vtime) |
| { |
| unsigned long long clock; |
| |
| clock = sched_clock(); |
| if (clock < vtime->starttime) |
| return 0; |
| |
| return clock - vtime->starttime; |
| } |
| |
| static u64 get_vtime_delta(struct vtime *vtime) |
| { |
| u64 delta = vtime_delta(vtime); |
| u64 other; |
| |
| /* |
| * Unlike tick based timing, vtime based timing never has lost |
| * ticks, and no need for steal time accounting to make up for |
| * lost ticks. Vtime accounts a rounded version of actual |
| * elapsed time. Limit account_other_time to prevent rounding |
| * errors from causing elapsed vtime to go negative. |
| */ |
| other = account_other_time(delta); |
| WARN_ON_ONCE(vtime->state == VTIME_INACTIVE); |
| vtime->starttime += delta; |
| |
| return delta - other; |
| } |
| |
| static void __vtime_account_system(struct task_struct *tsk, |
| struct vtime *vtime) |
| { |
| vtime->stime += get_vtime_delta(vtime); |
| if (vtime->stime >= TICK_NSEC) { |
| account_system_time(tsk, irq_count(), vtime->stime); |
| vtime->stime = 0; |
| } |
| } |
| |
| static void vtime_account_guest(struct task_struct *tsk, |
| struct vtime *vtime) |
| { |
| vtime->gtime += get_vtime_delta(vtime); |
| if (vtime->gtime >= TICK_NSEC) { |
| account_guest_time(tsk, vtime->gtime); |
| vtime->gtime = 0; |
| } |
| } |
| |
| void vtime_account_system(struct task_struct *tsk) |
| { |
| struct vtime *vtime = &tsk->vtime; |
| |
| if (!vtime_delta(vtime)) |
| return; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| /* We might have scheduled out from guest path */ |
| if (tsk->flags & PF_VCPU) |
| vtime_account_guest(tsk, vtime); |
| else |
| __vtime_account_system(tsk, vtime); |
| write_seqcount_end(&vtime->seqcount); |
| } |
| |
| void vtime_user_enter(struct task_struct *tsk) |
| { |
| struct vtime *vtime = &tsk->vtime; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| __vtime_account_system(tsk, vtime); |
| vtime->state = VTIME_USER; |
| write_seqcount_end(&vtime->seqcount); |
| } |
| |
| void vtime_user_exit(struct task_struct *tsk) |
| { |
| struct vtime *vtime = &tsk->vtime; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| vtime->utime += get_vtime_delta(vtime); |
| if (vtime->utime >= TICK_NSEC) { |
| account_user_time(tsk, vtime->utime); |
| vtime->utime = 0; |
| } |
| vtime->state = VTIME_SYS; |
| write_seqcount_end(&vtime->seqcount); |
| } |
| |
| void vtime_guest_enter(struct task_struct *tsk) |
| { |
| struct vtime *vtime = &tsk->vtime; |
| /* |
| * The flags must be updated under the lock with |
| * the vtime_starttime 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_seqcount_begin(&vtime->seqcount); |
| __vtime_account_system(tsk, vtime); |
| tsk->flags |= PF_VCPU; |
| write_seqcount_end(&vtime->seqcount); |
| } |
| EXPORT_SYMBOL_GPL(vtime_guest_enter); |
| |
| void vtime_guest_exit(struct task_struct *tsk) |
| { |
| struct vtime *vtime = &tsk->vtime; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| vtime_account_guest(tsk, vtime); |
| tsk->flags &= ~PF_VCPU; |
| write_seqcount_end(&vtime->seqcount); |
| } |
| EXPORT_SYMBOL_GPL(vtime_guest_exit); |
| |
| void vtime_account_idle(struct task_struct *tsk) |
| { |
| account_idle_time(get_vtime_delta(&tsk->vtime)); |
| } |
| |
| void arch_vtime_task_switch(struct task_struct *prev) |
| { |
| struct vtime *vtime = &prev->vtime; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| vtime->state = VTIME_INACTIVE; |
| write_seqcount_end(&vtime->seqcount); |
| |
| vtime = ¤t->vtime; |
| |
| write_seqcount_begin(&vtime->seqcount); |
| vtime->state = VTIME_SYS; |
| vtime->starttime = sched_clock(); |
| write_seqcount_end(&vtime->seqcount); |
| } |
| |
| void vtime_init_idle(struct task_struct *t, int cpu) |
| { |
| struct vtime *vtime = &t->vtime; |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| write_seqcount_begin(&vtime->seqcount); |
| vtime->state = VTIME_SYS; |
| vtime->starttime = sched_clock(); |
| write_seqcount_end(&vtime->seqcount); |
| local_irq_restore(flags); |
| } |
| |
| u64 task_gtime(struct task_struct *t) |
| { |
| struct vtime *vtime = &t->vtime; |
| unsigned int seq; |
| u64 gtime; |
| |
| if (!vtime_accounting_enabled()) |
| return t->gtime; |
| |
| do { |
| seq = read_seqcount_begin(&vtime->seqcount); |
| |
| gtime = t->gtime; |
| if (vtime->state == VTIME_SYS && t->flags & PF_VCPU) |
| gtime += vtime->gtime + vtime_delta(vtime); |
| |
| } while (read_seqcount_retry(&vtime->seqcount, 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. |
| */ |
| void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) |
| { |
| struct vtime *vtime = &t->vtime; |
| unsigned int seq; |
| u64 delta; |
| |
| if (!vtime_accounting_enabled()) { |
| *utime = t->utime; |
| *stime = t->stime; |
| return; |
| } |
| |
| do { |
| seq = read_seqcount_begin(&vtime->seqcount); |
| |
| *utime = t->utime; |
| *stime = t->stime; |
| |
| /* Task is sleeping, nothing to add */ |
| if (vtime->state == VTIME_INACTIVE || is_idle_task(t)) |
| continue; |
| |
| delta = vtime_delta(vtime); |
| |
| /* |
| * Task runs either in user or kernel space, add pending nohz time to |
| * the right place. |
| */ |
| if (vtime->state == VTIME_USER || t->flags & PF_VCPU) |
| *utime += vtime->utime + delta; |
| else if (vtime->state == VTIME_SYS) |
| *stime += vtime->stime + delta; |
| } while (read_seqcount_retry(&vtime->seqcount, seq)); |
| } |
| #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */ |