#include #include #include #include #include #include #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) { #ifdef CONFIG_CGROUP_CPUACCT struct kernel_cpustat *kcpustat; struct cpuacct *ca; #endif /* * 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. * */ __get_cpu_var(kernel_cpustat).cpustat[index] += tmp; #ifdef CONFIG_CGROUP_CPUACCT if (unlikely(!cpuacct_subsys.active)) return; rcu_read_lock(); ca = task_ca(p); while (ca && (ca != &root_cpuacct)) { kcpustat = this_cpu_ptr(ca->cpustat); kcpustat->cpustat[index] += tmp; ca = parent_ca(ca); } rcu_read_unlock(); #endif } /* * 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, st = 0; steal = paravirt_steal_clock(smp_processor_id()); steal -= this_rq()->prev_steal_time; st = steal_ticks(steal); this_rq()->prev_steal_time += st * TICK_NSEC; account_steal_time(st); return st; } #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(tsk, &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) { cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy); u64 *cpustat = kcpustat_this_cpu->cpustat; if (steal_account_process_tick()) return; if (irqtime_account_hi_update()) { cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy; } else if (irqtime_account_si_update()) { cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy; } 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_one_jiffy, one_jiffy_scaled, CPUTIME_SOFTIRQ); } else if (user_tick) { account_user_time(p, cputime_one_jiffy, one_jiffy_scaled); } else if (p == rq->idle) { account_idle_time(cputime_one_jiffy); } else if (p->flags & PF_VCPU) { /* System time or guest time */ account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled); } else { __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled, CPUTIME_SYSTEM); } } static void irqtime_account_idle_ticks(int ticks) { int i; struct rq *rq = this_rq(); for (i = 0; i < ticks; i++) irqtime_account_process_tick(current, 0, rq); } #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) {} #endif /* CONFIG_IRQ_TIME_ACCOUNTING */ #ifndef 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); 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)); } #endif /* !CONFIG_VIRT_CPU_ACCOUNTING_NATIVE */ /* * Use precise platform statistics if available: */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING 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; } #ifndef __ARCH_HAS_VTIME_TASK_SWITCH void vtime_task_switch(struct task_struct *prev) { if (!vtime_accounting_enabled()) return; 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_account_irq_enter(struct task_struct *tsk) { if (!vtime_accounting_enabled()) return; 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_account_irq_enter); #endif /* __ARCH_HAS_VTIME_ACCOUNT */ #else /* !CONFIG_VIRT_CPU_ACCOUNTING */ static cputime_t scale_utime(cputime_t utime, cputime_t rtime, cputime_t total) { u64 temp = (__force u64) rtime; temp *= (__force u64) utime; if (sizeof(cputime_t) == 4) temp = div_u64(temp, (__force u32) total); else temp = div64_u64(temp, (__force u64) total); return (__force cputime_t) temp; } /* * 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, utime, total; utime = curr->utime; total = utime + curr->stime; /* * 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); if (total) utime = scale_utime(utime, rtime, total); else utime = rtime; /* * If the tick based count grows faster than the scheduler one, * the result of the scaling may go backward. * Let's enforce monotonicity. */ prev->utime = max(prev->utime, utime); prev->stime = max(prev->stime, rtime - prev->utime); *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 */ #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN static unsigned long long vtime_delta(struct task_struct *tsk) { unsigned long long clock; clock = sched_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) { if (!vtime_accounting_enabled()) return; write_seqlock(&tsk->vtime_seqlock); __vtime_account_system(tsk); write_sequnlock(&tsk->vtime_seqlock); } void vtime_account_irq_exit(struct task_struct *tsk) { if (!vtime_accounting_enabled()) return; write_seqlock(&tsk->vtime_seqlock); if (context_tracking_in_user()) tsk->vtime_snap_whence = VTIME_USER; __vtime_account_system(tsk); write_sequnlock(&tsk->vtime_seqlock); } void vtime_account_user(struct task_struct *tsk) { cputime_t delta_cpu; if (!vtime_accounting_enabled()) return; delta_cpu = get_vtime_delta(tsk); write_seqlock(&tsk->vtime_seqlock); 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) { if (!vtime_accounting_enabled()) return; write_seqlock(&tsk->vtime_seqlock); tsk->vtime_snap_whence = VTIME_USER; __vtime_account_system(tsk); write_sequnlock(&tsk->vtime_seqlock); } void vtime_guest_enter(struct task_struct *tsk) { write_seqlock(&tsk->vtime_seqlock); __vtime_account_system(tsk); current->flags |= PF_VCPU; write_sequnlock(&tsk->vtime_seqlock); } 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); } void vtime_account_idle(struct task_struct *tsk) { cputime_t delta_cpu = get_vtime_delta(tsk); account_idle_time(delta_cpu); } bool vtime_accounting_enabled(void) { return context_tracking_active(); } 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(); write_sequnlock(¤t->vtime_seqlock); } void vtime_init_idle(struct task_struct *t) { unsigned long flags; write_seqlock_irqsave(&t->vtime_seqlock, flags); t->vtime_snap_whence = VTIME_SYS; t->vtime_snap = sched_clock(); write_sequnlock_irqrestore(&t->vtime_seqlock, flags); } cputime_t task_gtime(struct task_struct *t) { unsigned long flags; unsigned int seq; cputime_t gtime; do { seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags); gtime = t->gtime; if (t->flags & PF_VCPU) gtime += vtime_delta(t); } while (read_seqretry_irqrestore(&t->vtime_seqlock, seq, flags)); 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 long flags; unsigned int seq; unsigned long long delta; do { *udelta = 0; *sdelta = 0; seq = read_seqbegin_irqsave(&t->vtime_seqlock, flags); 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_irqrestore(&t->vtime_seqlock, seq, flags)); } 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 */