--- /dev/null
+#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;
+ unsigned int seq, nextseq;
+ unsigned long flags;
+
+ 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 += task_sched_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)
+{
+ 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;
+}
+
+/*
+ * Atomically advance counter to the new value. Interrupts, vcpu
+ * scheduling, and scaling inaccuracies can cause cputime_advance
+ * to be occasionally called with a new value smaller than counter.
+ * Let's enforce atomicity.
+ *
+ * Normally a caller will only go through this loop once, or not
+ * at all in case a previous caller updated counter the same jiffy.
+ */
+static void cputime_advance(cputime_t *counter, cputime_t new)
+{
+ cputime_t old;
+
+ while (new > (old = ACCESS_ONCE(*counter)))
+ cmpxchg_cputime(counter, old, new);
+}
+
+/*
+ * 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;
+ }
+
+ cputime_advance(&prev->stime, stime);
+ cputime_advance(&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);
+}
+
+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)
+{
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ __vtime_account_system(tsk);
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+
+void vtime_gen_account_irq_exit(struct task_struct *tsk)
+{
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ __vtime_account_system(tsk);
+ if (context_tracking_in_user())
+ tsk->vtime_snap_whence = VTIME_USER;
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+
+void vtime_account_user(struct task_struct *tsk)
+{
+ cputime_t delta_cpu;
+
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ delta_cpu = get_vtime_delta(tsk);
+ tsk->vtime_snap_whence = VTIME_SYS;
+ account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+
+void vtime_user_enter(struct task_struct *tsk)
+{
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ __vtime_account_system(tsk);
+ tsk->vtime_snap_whence = VTIME_USER;
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+
+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.
+ */
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ __vtime_account_system(tsk);
+ current->flags |= PF_VCPU;
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+EXPORT_SYMBOL_GPL(vtime_guest_enter);
+
+void vtime_guest_exit(struct task_struct *tsk)
+{
+ raw_spin_lock(&tsk->vtime_lock);
+ write_seqcount_begin(&tsk->vtime_seq);
+ __vtime_account_system(tsk);
+ current->flags &= ~PF_VCPU;
+ write_seqcount_end(&tsk->vtime_seq);
+ raw_spin_unlock(&tsk->vtime_lock);
+}
+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)
+{
+ raw_spin_lock(&prev->vtime_lock);
+ write_seqcount_begin(&prev->vtime_seq);
+ prev->vtime_snap_whence = VTIME_SLEEPING;
+ write_seqcount_end(&prev->vtime_seq);
+ raw_spin_unlock(&prev->vtime_lock);
+
+ raw_spin_lock(¤t->vtime_lock);
+ write_seqcount_begin(¤t->vtime_seq);
+ current->vtime_snap_whence = VTIME_SYS;
+ current->vtime_snap = sched_clock_cpu(smp_processor_id());
+ write_seqcount_end(¤t->vtime_seq);
+ raw_spin_unlock(¤t->vtime_lock);
+}
+
+void vtime_init_idle(struct task_struct *t, int cpu)
+{
+ unsigned long flags;
+
+ raw_spin_lock_irqsave(&t->vtime_lock, flags);
+ write_seqcount_begin(&t->vtime_seq);
+ t->vtime_snap_whence = VTIME_SYS;
+ t->vtime_snap = sched_clock_cpu(cpu);
+ write_seqcount_end(&t->vtime_seq);
+ raw_spin_unlock_irqrestore(&t->vtime_lock, flags);
+}
+
+cputime_t task_gtime(struct task_struct *t)
+{
+ unsigned int seq;
+ cputime_t gtime;
+
+ do {
+ seq = read_seqcount_begin(&t->vtime_seq);
+
+ gtime = t->gtime;
+ if (t->flags & PF_VCPU)
+ gtime += vtime_delta(t);
+
+ } while (read_seqcount_retry(&t->vtime_seq, 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_seqcount_begin(&t->vtime_seq);
+
+ 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_seqcount_retry(&t->vtime_seq, 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 */
Code Review / kvmfornfv.git / blobdiff