// 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 before incrementing preempt_count on {soft,}irq_enter
* and before decrementing preempt_count on {soft,}irq_exit.
*/
void irqtime_account_irq(struct task_struct *curr)
{
struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
s64 delta;
int cpu;
if (!sched_clock_irqtime)
return;
cpu = smp_processor_id();
delta = sched_clock_cpu(cpu) - irqtime->irq_start_time;
irqtime->irq_start_time += delta;
/*
* We do not account for softirq time from ksoftirqd here.
* We want to continue accounting softirq time to ksoftirqd thread
* in that case, so as not to confuse scheduler with a special task
* that do not consume any time, but still wants to run.
*/
if (hardirq_count())
irqtime_account_delta(irqtime, delta, CPUTIME_IRQ);
else if (in_serving_softirq() && curr != this_cpu_ksoftirqd())
irqtime_account_delta(irqtime, delta, CPUTIME_SOFTIRQ);
}
EXPORT_SYMBOL_GPL(irqtime_account_irq);
static u64 irqtime_tick_accounted(u64 maxtime)
{
struct irqtime *irqtime = this_cpu_ptr(&cpu_irqtime);
u64 delta;
delta = min(irqtime->tick_delta, maxtime);
irqtime->tick_delta -= delta;
return delta;
}
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
#define sched_clock_irqtime (0)
static u64 irqtime_tick_accounted(u64 dummy)
{
return 0;
}
#endif /* !CONFIG_IRQ_TIME_ACCOUNTING */
static inline void task_group_account_field(struct task_struct *p, int index,
u64 tmp)
{
/*
* Since all updates are sure to touch the root cgroup, we
* get ourselves ahead and touch it first. If the root cgroup
* is the only cgroup, then nothing else should be necessary.
*
*/
__this_cpu_add(kernel_cpustat.cpustat[index], tmp);
cgroup_account_cputime_field(p, index, tmp);
}
/*
* Account user CPU time to a process.
* @p: the process that the CPU time gets accounted to
* @cputime: the CPU time spent in user space since the last update
*/
void account_user_time(struct task_struct *p, u64 cputime)
{
int index;
/* Add user time to process. */
p->utime += cputime;
account_group_user_time(p, cputime);
index = (task_nice(p) > 0) ? CPUTIME_NICE : CPUTIME_USER;
/* Add user time to cpustat. */
task_group_account_field(p, index, cputime);
/* Account for user time used */
acct_account_cputime(p);
}
/*
* Account 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;
}