From: Peter Zijlstra <peterz@infradead.org>
To: Vincent Guittot <vincent.guittot@linaro.org>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Valentin Schneider <valentin.schneider@arm.com>,
Morten Rasmussen <morten.rasmussen@foss.arm.com>,
Brendan Jackman <brendan.jackman@arm.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Will Deacon <will.deacon@arm.com>
Subject: Re: [PATCH v2 1/3] sched: Stop nohz stats when decayed
Date: Fri, 9 Feb 2018 13:00:53 +0100 [thread overview]
Message-ID: <20180209120053.GL25201@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <CAKfTPtA0kmgD0XtMMweESojfuGFW1t9fT53=2QqtrJVbPV4QBw@mail.gmail.com>
On Thu, Feb 08, 2018 at 05:52:00PM +0100, Vincent Guittot wrote:
> On 8 February 2018 at 16:44, Peter Zijlstra <peterz@infradead.org> wrote:
> > On Thu, Feb 08, 2018 at 04:05:58PM +0100, Vincent Guittot wrote:
> >> On 8 February 2018 at 15:00, Peter Zijlstra <peterz@infradead.org> wrote:
> >> > On Tue, Feb 06, 2018 at 08:23:05PM +0100, Vincent Guittot wrote:
> >> >
> >> >> @@ -9207,13 +9231,15 @@ void nohz_balance_enter_idle(int cpu)
> >> >> if (!housekeeping_cpu(cpu, HK_FLAG_SCHED))
> >> >> return;
> >> >>
> >> >> + rq->has_blocked_load = 1;
> >
> > Should we not set that with rq->lock held? We already clear it while
> > holding rq->lock.
>
> I think it's safe because it is used to re-enable the periodic decay
> unconditionally.
> It is cleared with rq->lock held to prevents any update of the cfs_rq
> *_avg while deciding if we can clear has_blocked_load
Yes, and that clearing must then have observed the new addition. But
please put so in a comment.
next prev parent reply other threads:[~2018-02-09 12:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-06 19:23 [PATCH v2 0/3] Update blocked load Vincent Guittot
2018-02-06 19:23 ` [PATCH v2 1/3] sched: Stop nohz stats when decayed Vincent Guittot
2018-02-08 12:46 ` Valentin Schneider
2018-02-08 13:15 ` Peter Zijlstra
2018-02-08 13:36 ` Vincent Guittot
2018-02-08 19:21 ` Valentin Schneider
2018-02-09 11:41 ` Vincent Guittot
2018-02-09 12:16 ` Valentin Schneider
2018-02-08 14:00 ` Peter Zijlstra
2018-02-08 14:04 ` Peter Zijlstra
2018-02-08 15:05 ` Vincent Guittot
2018-02-08 15:44 ` Peter Zijlstra
2018-02-08 16:52 ` Vincent Guittot
2018-02-09 12:00 ` Peter Zijlstra [this message]
2018-02-08 15:30 ` Will Deacon
2018-02-08 15:46 ` Peter Zijlstra
2018-02-08 16:03 ` Will Deacon
2018-02-09 9:51 ` Andrea Parri
2018-02-06 19:23 ` [PATCH v2 2/3] sched: reduce the periodic update duration Vincent Guittot
2018-02-06 19:23 ` [PATCH v2 3/3] sched: update blocked load when newly idle Vincent Guittot
2018-02-06 21:25 ` [PATCH v2 0/3] Update blocked load Peter Zijlstra
2018-02-06 21:46 ` Vincent Guittot
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