Commit e6d5bf3e authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Ingo Molnar
Browse files

sched/cputime: Add vtime guest task state 



Record guest as a VTIME state instead of guessing it from VTIME_SYS and
PF_VCPU. 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/20191016025700.31277-4-frederic@kernel.org


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 14faf6fc

include/linux/sched.h

+2 −0
Original line number Diff line number Diff line
@@ -255,6 +255,8 @@ enum vtime_state { 
	VTIME_SYS,

	/* Task runs in userspace in a CPU with VTIME active: */

	VTIME_USER,

	/* Task runs as guests in a CPU with VTIME active: */

	VTIME_GUEST,

};



struct vtime {

kernel/sched/cputime.c

+11 −7
Original line number Diff line number Diff line
@@ -733,7 +733,7 @@ static void __vtime_account_kernel(struct task_struct *tsk, 
				   struct vtime *vtime)

{

	/* We might have scheduled out from guest path */

	if (tsk->flags & PF_VCPU)

	if (vtime->state == VTIME_GUEST)

		vtime_account_guest(tsk, vtime);

	else

		vtime_account_system(tsk, vtime);
@@ -788,6 +788,7 @@ void vtime_guest_enter(struct task_struct *tsk) 
	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);
@@ -799,6 +800,7 @@ void vtime_guest_exit(struct task_struct *tsk) 
	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);
@@ -826,6 +828,8 @@ void vtime_task_switch_generic(struct task_struct *prev) 
	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();
@@ -860,7 +864,7 @@ u64 task_gtime(struct task_struct *t) 
		seq = read_seqcount_begin(&vtime->seqcount);



		gtime = t->gtime;

		if (vtime->state == VTIME_SYS && t->flags & PF_VCPU)

		if (vtime->state == VTIME_GUEST)

			gtime += vtime->gtime + vtime_delta(vtime);



	} while (read_seqcount_retry(&vtime->seqcount, seq));
@@ -898,13 +902,13 @@ void task_cputime(struct task_struct *t, u64 *utime, u64 *stime) 
		delta = vtime_delta(vtime);



		/*

		 * Task runs either in user or kernel space, add pending nohz time to

		 * the right place.

		 * Task runs either in user (including guest) or kernel space,

		 * add pending nohz time to the right place.

		 */

		if (vtime->state == VTIME_USER || t->flags & PF_VCPU)

			*utime += vtime->utime + delta;

		else if (vtime->state == VTIME_SYS)

		if (vtime->state == VTIME_SYS)

			*stime += vtime->stime + delta;

		else

			*utime += vtime->utime + delta;

	} while (read_seqcount_retry(&vtime->seqcount, seq));

}

#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */

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