1085 строки
26 KiB
C
1085 строки
26 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
|
|
/*
|
|
* Simple CPU accounting cgroup controller
|
|
*/
|
|
#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 after 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 int offset)
|
|
{
|
|
struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
|
|
unsigned int pc;
|
|
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;
|
|
pc = irq_count() - offset;
|
|
|
|
/*
|
|
* 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 (pc & HARDIRQ_MASK)
|
|
irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
|
|
else if ((pc & SOFTIRQ_OFFSET) && curr != this_cpu_ksoftirqd())
|
|
irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
|
|
}
|
|
|
|
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 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 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,
|
|
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);
|
|
}
|
|
}
|
|
|
|
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
|
|
|
|
void vtime_account_irq(struct task_struct *tsk, unsigned int offset)
|
|
{
|
|
unsigned int pc = irq_count() - offset;
|
|
|
|
if (pc & HARDIRQ_OFFSET) {
|
|
vtime_account_hardirq(tsk);
|
|
} else if (pc & SOFTIRQ_OFFSET) {
|
|
vtime_account_softirq(tsk);
|
|
} else if (!IS_ENABLED(CONFIG_HAVE_VIRT_CPU_ACCOUNTING_IDLE) &&
|
|
is_idle_task(tsk)) {
|
|
vtime_account_idle(tsk);
|
|
} else {
|
|
vtime_account_kernel(tsk);
|
|
}
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
#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;
|
|
|
|
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 monotonicity 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,
|
|
};
|
|
|
|
if (task_cputime(p, &cputime.utime, &cputime.stime))
|
|
cputime.sum_exec_runtime = task_sched_runtime(p);
|
|
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);
|
|
}
|
|
#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 = ¤t->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.
|
|
*/
|
|
bool task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
|
|
{
|
|
struct vtime *vtime = &t->vtime;
|
|
unsigned int seq;
|
|
u64 delta;
|
|
int ret;
|
|
|
|
if (!vtime_accounting_enabled()) {
|
|
*utime = t->utime;
|
|
*stime = t->stime;
|
|
return false;
|
|
}
|
|
|
|
do {
|
|
ret = false;
|
|
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;
|
|
|
|
ret = true;
|
|
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));
|
|
|
|
return ret;
|
|
}
|
|
|
|
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 */
|