Commit 14faf6fc authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
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sched/cputime: Add vtime idle task state 



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: default avatarFrederic Weisbecker <frederic@kernel.org>
Signed-off-by: default avatarPeter 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: default avatarIngo Molnar <mingo@kernel.org>
parent 802f4a82

include/linux/sched.h

+4 −2
Original line number Diff line number Diff line
@@ -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 {

kernel/sched/cputime.c

+8 −5
Original line number Diff line number Diff line
@@ -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);
@@ -824,6 +824,9 @@ void vtime_task_switch_generic(struct task_struct *prev) 
	vtime = &current->vtime;



	write_seqcount_begin(&vtime->seqcount);

	if (is_idle_task(current))

		vtime->state = VTIME_IDLE;

	else

		vtime->state = VTIME_SYS;

	vtime->starttime = sched_clock();

	vtime->cpu = smp_processor_id();
@@ -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);

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