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| author |   Frederic Weisbecker <frederic@kernel.org> | 2019-10-16 04:56:47 +0200 |
|---|---|---|
| committer |   Ingo Molnar <mingo@kernel.org> | 2019-10-29 10:01:08 +0100 |
| commit | 802f4a827f139f2581b3c50c69d20f8bf4c24af1 (patch) | |
| tree | 81e4f1ef045fbaa2a8bce0839809102778543bc1 /kernel/sched/cputime.c | |
| parent | sched/fair/util_est: Implement faster ramp-up EWMA on utilization increases (diff) | |
| download | linux-dev-802f4a827f139f2581b3c50c69d20f8bf4c24af1.tar.xz linux-dev-802f4a827f139f2581b3c50c69d20f8bf4c24af1.zip | |
sched/vtime: Record CPU under seqcount for kcpustat needs
In order to compute the kcpustat delta on a nohz CPU, we'll need to
fetch the task running on that target. Checking that its vtime
state snapshot actually refers to the relevant target involves recording
that CPU under the seqcount locked on task switch.
This is a step toward making kcpustat moving forward on full nohz CPUs.
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/20191016025700.31277-2-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/sched/cputime.c')
| -rw-r--r-- | kernel/sched/cputime.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c index cef23c211f41..40f581692254 100644 --- a/kernel/sched/cputime.c +++ b/kernel/sched/cputime.c @@ -818,6 +818,7 @@ void vtime_task_switch_generic(struct task_struct *prev) else __vtime_account_kernel(prev, vtime); vtime->state = VTIME_INACTIVE; + vtime->cpu = -1; write_seqcount_end(&vtime->seqcount); vtime = ¤t->vtime; @@ -825,6 +826,7 @@ void vtime_task_switch_generic(struct task_struct *prev) write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; vtime->starttime = sched_clock(); + vtime->cpu = smp_processor_id(); write_seqcount_end(&vtime->seqcount); } @@ -837,6 +839,7 @@ void vtime_init_idle(struct task_struct *t, int cpu) write_seqcount_begin(&vtime->seqcount); vtime->state = VTIME_SYS; vtime->starttime = sched_clock(); + vtime->cpu = cpu; write_seqcount_end(&vtime->seqcount); local_irq_restore(flags); } |