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sched/cputime: Add vtime idle task state

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Record idle as a VTIME state instead of guessing it from VTIME_SYS and
is_idle_task(). This is going to simplify the cputime read side
especially as its state machine is going to further expand in order to
fully support kcpustat on nohz_full.

Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jacek Anaszewski <jacek.anaszewski@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J . Wysocki <rjw@rjwysocki.net>
Cc: Rik van Riel <riel@surriel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Viresh Kumar <viresh.kumar@linaro.org>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Yauheni Kaliuta <yauheni.kaliuta@redhat.com>
Link: https://lkml.kernel.org/r/20191016025700.31277-3-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker 2019-10-16 04:56:48 +02:00 committed by Ingo Molnar
parent 802f4a827f
commit 14faf6fcac
2 changed files with 12 additions and 7 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

6
include/linux/sched.h
View file

@ -249,10 +249,12 @@ struct prev_cputime {
enum vtime_state {
/* Task is sleeping or running in a CPU with VTIME inactive: */
VTIME_INACTIVE = 0,
/* Task runs in userspace in a CPU with VTIME active: */
VTIME_USER,
/* Task is idle */
VTIME_IDLE,
/* Task runs in kernelspace in a CPU with VTIME active: */
VTIME_SYS,
/* Task runs in userspace in a CPU with VTIME active: */
VTIME_USER,
};
struct vtime {

13
kernel/sched/cputime.c
View file

@ -813,7 +813,7 @@ void vtime_task_switch_generic(struct task_struct *prev)
struct vtime *vtime = &prev->vtime;
write_seqcount_begin(&vtime->seqcount);
if (is_idle_task(prev))
if (vtime->state == VTIME_IDLE)
vtime_account_idle(prev);
else
__vtime_account_kernel(prev, vtime);
@ -824,7 +824,10 @@ void vtime_task_switch_generic(struct task_struct *prev)
vtime = &current->vtime;
write_seqcount_begin(&vtime->seqcount);
vtime->state = VTIME_SYS;
if (is_idle_task(current))
vtime->state = VTIME_IDLE;
else
vtime->state = VTIME_SYS;
vtime->starttime = sched_clock();
vtime->cpu = smp_processor_id();
write_seqcount_end(&vtime->seqcount);
@ -837,7 +840,7 @@ void vtime_init_idle(struct task_struct *t, int cpu)
local_irq_save(flags);
write_seqcount_begin(&vtime->seqcount);
vtime->state = VTIME_SYS;
vtime->state = VTIME_IDLE;
vtime->starttime = sched_clock();
vtime->cpu = cpu;
write_seqcount_end(&vtime->seqcount);
@ -888,8 +891,8 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime)
*utime = t->utime;
*stime = t->stime;
/* Task is sleeping, nothing to add */
if (vtime->state == VTIME_INACTIVE || is_idle_task(t))
/* Task is sleeping or idle, nothing to add */
if (vtime->state < VTIME_SYS)
continue;
delta = vtime_delta(vtime);