Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Simple CPU accounting cgroup controller
 */
#include <linux/cpufreq_times.h>
#include "sched.h"
#include <trace/hooks/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);
EXPORT_PER_CPU_SYMBOL_GPL(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);
 
<------>trace_android_rvh_account_irq(curr, cpu, delta);
}
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) {
<------><------>task_group_account_field(p, CPUTIME_NICE, cputime);
<------><------>cpustat[CPUTIME_GUEST_NICE] += cputime;
<------>} else {
<------><------>task_group_account_field(p, 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(&paravirt_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,
<------><------><------><------><------> 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 == this_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);
<------>}
<------>trace_android_vh_irqtime_account_process_tick(p, this_rq(), user_tick, ticks);
}
 
static void irqtime_account_idle_ticks(int ticks)
{
<------>irqtime_account_process_tick(current, 0, 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,
<------><------><------><------><------><------>int nr_ticks) { }
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
 
/*
 * Use precise platform statistics if available:
 */
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE
 
# ifndef __ARCH_HAS_VTIME_TASK_SWITCH
void vtime_task_switch(struct task_struct *prev)
{
<------>if (is_idle_task(prev))
<------><------>vtime_account_idle(prev);
<------>else
<------><------>vtime_account_kernel(prev);
 
<------>vtime_flush(prev);
<------>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_kernel() 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_kernel(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;
 
<------>if (vtime_accounting_enabled_this_cpu())
<------><------>return;
<------>trace_android_vh_account_task_time(p, this_rq(), user_tick);
 
<------>if (sched_clock_irqtime) {
<------><------>irqtime_account_process_tick(p, user_tick, 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 != this_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);
}
 
/*
 * 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 = mul_u64_u64_div_u64(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;
<------>}
}
 
static void __vtime_account_kernel(struct task_struct *tsk,
<------><------><------><------>   struct vtime *vtime)
{
<------>/* We might have scheduled out from guest path */
<------>if (vtime->state == VTIME_GUEST)
<------><------>vtime_account_guest(tsk, vtime);
<------>else
<------><------>vtime_account_system(tsk, vtime);
}
 
void vtime_account_kernel(struct task_struct *tsk)
{
<------>struct vtime *vtime = &tsk->vtime;
 
<------>if (!vtime_delta(vtime))
<------><------>return;
 
<------>write_seqcount_begin(&vtime->seqcount);
<------>__vtime_account_kernel(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;
<------>vtime->state = VTIME_GUEST;
<------>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;
<------>vtime->state = VTIME_SYS;
<------>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 vtime_task_switch_generic(struct task_struct *prev)
{
<------>struct vtime *vtime = &prev->vtime;
 
<------>write_seqcount_begin(&vtime->seqcount);
<------>if (vtime->state == VTIME_IDLE)
<------><------>vtime_account_idle(prev);
<------>else
<------><------>__vtime_account_kernel(prev, vtime);
<------>vtime->state = VTIME_INACTIVE;
<------>vtime->cpu = -1;
<------>write_seqcount_end(&vtime->seqcount);
 
<------>vtime = &current->vtime;
 
<------>write_seqcount_begin(&vtime->seqcount);
<------>if (is_idle_task(current))
<------><------>vtime->state = VTIME_IDLE;
<------>else if (current->flags & PF_VCPU)
<------><------>vtime->state = VTIME_GUEST;
<------>else
<------><------>vtime->state = VTIME_SYS;
<------>vtime->starttime = sched_clock();
<------>vtime->cpu = smp_processor_id();
<------>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_IDLE;
<------>vtime->starttime = sched_clock();
<------>vtime->cpu = cpu;
<------>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_GUEST)
<------><------><------>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 or idle, nothing to add */
<------><------>if (vtime->state < VTIME_SYS)
<------><------><------>continue;
 
<------><------>delta = vtime_delta(vtime);
 
<------><------>/*
<------><------> * Task runs either in user (including guest) or kernel space,
<------><------> * add pending nohz time to the right place.
<------><------> */
<------><------>if (vtime->state == VTIME_SYS)
<------><------><------>*stime += vtime->stime + delta;
<------><------>else
<------><------><------>*utime += vtime->utime + delta;
<------>} while (read_seqcount_retry(&vtime->seqcount, seq));
}
 
static int vtime_state_fetch(struct vtime *vtime, int cpu)
{
<------>int state = READ_ONCE(vtime->state);
 
<------>/*
<------> * We raced against a context switch, fetch the
<------> * kcpustat task again.
<------> */
<------>if (vtime->cpu != cpu && vtime->cpu != -1)
<------><------>return -EAGAIN;
 
<------>/*
<------> * Two possible things here:
<------> * 1) We are seeing the scheduling out task (prev) or any past one.
<------> * 2) We are seeing the scheduling in task (next) but it hasn't
<------> *    passed though vtime_task_switch() yet so the pending
<------> *    cputime of the prev task may not be flushed yet.
<------> *
<------> * Case 1) is ok but 2) is not. So wait for a safe VTIME state.
<------> */
<------>if (state == VTIME_INACTIVE)
<------><------>return -EAGAIN;
 
<------>return state;
}
 
static u64 kcpustat_user_vtime(struct vtime *vtime)
{
<------>if (vtime->state == VTIME_USER)
<------><------>return vtime->utime + vtime_delta(vtime);
<------>else if (vtime->state == VTIME_GUEST)
<------><------>return vtime->gtime + vtime_delta(vtime);
<------>return 0;
}
 
static int kcpustat_field_vtime(u64 *cpustat,
<------><------><------><------>struct task_struct *tsk,
<------><------><------><------>enum cpu_usage_stat usage,
<------><------><------><------>int cpu, u64 *val)
{
<------>struct vtime *vtime = &tsk->vtime;
<------>unsigned int seq;
 
<------>do {
<------><------>int state;
 
<------><------>seq = read_seqcount_begin(&vtime->seqcount);
 
<------><------>state = vtime_state_fetch(vtime, cpu);
<------><------>if (state < 0)
<------><------><------>return state;
 
<------><------>*val = cpustat[usage];
 
<------><------>/*
<------><------> * Nice VS unnice cputime accounting may be inaccurate if
<------><------> * the nice value has changed since the last vtime update.
<------><------> * But proper fix would involve interrupting target on nice
<------><------> * updates which is a no go on nohz_full (although the scheduler
<------><------> * may still interrupt the target if rescheduling is needed...)
<------><------> */
<------><------>switch (usage) {
<------><------>case CPUTIME_SYSTEM:
<------><------><------>if (state == VTIME_SYS)
<------><------><------><------>*val += vtime->stime + vtime_delta(vtime);
<------><------><------>break;
<------><------>case CPUTIME_USER:
<------><------><------>if (task_nice(tsk) <= 0)
<------><------><------><------>*val += kcpustat_user_vtime(vtime);
<------><------><------>break;
<------><------>case CPUTIME_NICE:
<------><------><------>if (task_nice(tsk) > 0)
<------><------><------><------>*val += kcpustat_user_vtime(vtime);
<------><------><------>break;
<------><------>case CPUTIME_GUEST:
<------><------><------>if (state == VTIME_GUEST && task_nice(tsk) <= 0)
<------><------><------><------>*val += vtime->gtime + vtime_delta(vtime);
<------><------><------>break;
<------><------>case CPUTIME_GUEST_NICE:
<------><------><------>if (state == VTIME_GUEST && task_nice(tsk) > 0)
<------><------><------><------>*val += vtime->gtime + vtime_delta(vtime);
<------><------><------>break;
<------><------>default:
<------><------><------>break;
<------><------>}
<------>} while (read_seqcount_retry(&vtime->seqcount, seq));
 
<------>return 0;
}
 
u64 kcpustat_field(struct kernel_cpustat *kcpustat,
<------><------>   enum cpu_usage_stat usage, int cpu)
{
<------>u64 *cpustat = kcpustat->cpustat;
<------>u64 val = cpustat[usage];
<------>struct rq *rq;
<------>int err;
 
<------>if (!vtime_accounting_enabled_cpu(cpu))
<------><------>return val;
 
<------>rq = cpu_rq(cpu);
 
<------>for (;;) {
<------><------>struct task_struct *curr;
 
<------><------>rcu_read_lock();
<------><------>curr = rcu_dereference(rq->curr);
<------><------>if (WARN_ON_ONCE(!curr)) {
<------><------><------>rcu_read_unlock();
<------><------><------>return cpustat[usage];
<------><------>}
 
<------><------>err = kcpustat_field_vtime(cpustat, curr, usage, cpu, &val);
<------><------>rcu_read_unlock();
 
<------><------>if (!err)
<------><------><------>return val;
 
<------><------>cpu_relax();
<------>}
}
EXPORT_SYMBOL_GPL(kcpustat_field);
 
static int kcpustat_cpu_fetch_vtime(struct kernel_cpustat *dst,
<------><------><------><------>    const struct kernel_cpustat *src,
<------><------><------><------>    struct task_struct *tsk, int cpu)
{
<------>struct vtime *vtime = &tsk->vtime;
<------>unsigned int seq;
 
<------>do {
<------><------>u64 *cpustat;
<------><------>u64 delta;
<------><------>int state;
 
<------><------>seq = read_seqcount_begin(&vtime->seqcount);
 
<------><------>state = vtime_state_fetch(vtime, cpu);
<------><------>if (state < 0)
<------><------><------>return state;
 
<------><------>*dst = *src;
<------><------>cpustat = dst->cpustat;
 
<------><------>/* Task is sleeping, dead or idle, nothing to add */
<------><------>if (state < VTIME_SYS)
<------><------><------>continue;
 
<------><------>delta = vtime_delta(vtime);
 
<------><------>/*
<------><------> * Task runs either in user (including guest) or kernel space,
<------><------> * add pending nohz time to the right place.
<------><------> */
<------><------>if (state == VTIME_SYS) {
<------><------><------>cpustat[CPUTIME_SYSTEM] += vtime->stime + delta;
<------><------>} else if (state == VTIME_USER) {
<------><------><------>if (task_nice(tsk) > 0)
<------><------><------><------>cpustat[CPUTIME_NICE] += vtime->utime + delta;
<------><------><------>else
<------><------><------><------>cpustat[CPUTIME_USER] += vtime->utime + delta;
<------><------>} else {
<------><------><------>WARN_ON_ONCE(state != VTIME_GUEST);
<------><------><------>if (task_nice(tsk) > 0) {
<------><------><------><------>cpustat[CPUTIME_GUEST_NICE] += vtime->gtime + delta;
<------><------><------><------>cpustat[CPUTIME_NICE] += vtime->gtime + delta;
<------><------><------>} else {
<------><------><------><------>cpustat[CPUTIME_GUEST] += vtime->gtime + delta;
<------><------><------><------>cpustat[CPUTIME_USER] += vtime->gtime + delta;
<------><------><------>}
<------><------>}
<------>} while (read_seqcount_retry(&vtime->seqcount, seq));
 
<------>return 0;
}
 
void kcpustat_cpu_fetch(struct kernel_cpustat *dst, int cpu)
{
<------>const struct kernel_cpustat *src = &kcpustat_cpu(cpu);
<------>struct rq *rq;
<------>int err;
 
<------>if (!vtime_accounting_enabled_cpu(cpu)) {
<------><------>*dst = *src;
<------><------>return;
<------>}
 
<------>rq = cpu_rq(cpu);
 
<------>for (;;) {
<------><------>struct task_struct *curr;
 
<------><------>rcu_read_lock();
<------><------>curr = rcu_dereference(rq->curr);
<------><------>if (WARN_ON_ONCE(!curr)) {
<------><------><------>rcu_read_unlock();
<------><------><------>*dst = *src;
<------><------><------>return;
<------><------>}
 
<------><------>err = kcpustat_cpu_fetch_vtime(dst, src, curr, cpu);
<------><------>rcu_read_unlock();
 
<------><------>if (!err)
<------><------><------>return;
 
<------><------>cpu_relax();
<------>}
}
EXPORT_SYMBOL_GPL(kcpustat_cpu_fetch);
 
#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */