From: Chris Metcalf <cmetcalf@mellanox.com>
To: Rik van Riel <riel@redhat.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Christoph Lameter <cl@linux.com>, Ingo Molnar <mingo@kernel.org>,
Luiz Capitulino <lcapitulino@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Viresh Kumar <viresh.kumar@linaro.org>,
<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] nohz_full: Make sched_should_stop_tick() more conservative
Date: Mon, 4 Apr 2016 20:27:30 -0400 [thread overview]
Message-ID: <57030672.8080405@mellanox.com> (raw)
In-Reply-To: <1459798571.6219.23.camel@redhat.com>
On 4/4/2016 3:36 PM, Rik van Riel wrote:
>>> On Fri, 2016-04-01 at 15:42 -0400, Chris Metcalf wrote:
>>>> On arm64, when calling enqueue_task_fair() from
>>>> migration_cpu_stop(),
>>>> we find the nr_running value updated by add_nr_running(), but the
>>>> cfs.nr_running value has not always yet been
>>>> updated. Accordingly,
>>>> the sched_can_stop_tick() false returns true when we are
>>>> migrating a
>>>> second task onto a core.
>>>> Correct this by using rq->nr_running instead of rq-
>>>>> cfs.nr_running.
>>>> This should always be more conservative, and reverts the test to
>>>> the
>>>> form it had before commit 76d92ac305f2 ("sched: Migrate sched to
>>>> use
>>>> new tick dependency mask model").
>>>>
>>>>
> [...]
>
> Patch gets my:
>
> Acked-by: Rik van Riel <riel@redhat.com>
Thanks! Whose tree should this go through: Frederic, PeterZ, Ingo?
Do any of you have any concerns with it?
--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com
prev parent reply other threads:[~2016-04-05 0:27 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-04-01 19:42 [PATCH] nohz_full: Make sched_should_stop_tick() more conservative Chris Metcalf
2016-04-04 19:12 ` Rik van Riel
2016-04-04 19:23 ` Peter Zijlstra
2016-04-18 2:00 ` Wanpeng Li
2016-04-21 14:42 ` Peter Zijlstra
2016-04-21 16:03 ` Peter Zijlstra
2016-04-25 21:30 ` Chris Metcalf
2016-04-28 10:24 ` [tip:sched/urgent] nohz/full, sched/rt: Fix missed tick-reenabling bug in sched_can_stop_tick() tip-bot for Peter Zijlstra
2016-04-28 13:30 ` Frederic Weisbecker
2016-04-04 19:31 ` [PATCH] nohz_full: Make sched_should_stop_tick() more conservative Chris Metcalf
2016-04-04 19:36 ` Rik van Riel
2016-04-05 0:27 ` Chris Metcalf [this message]
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