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sched/cputime: Add vtime guest task state

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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: 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/20191016025700.31277-4-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Frederic Weisbecker 2019-10-16 04:56:49 +02:00 committed by Ingo Molnar
parent 14faf6fcac
commit e6d5bf3e32
2 changed files with 13 additions and 7 deletions
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2
include/linux/sched.h
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@ -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 {

18
kernel/sched/cputime.c
View File

@ -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 */