From: Vincent Guittot <vincent.guittot@linaro.org>
To: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Juri Lelli <juri.lelli@redhat.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
linux-kernel <linux-kernel@vger.kernel.org>,
Odin Ugedal <odin@uged.al>,
"open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>
Subject: Re: [PATCH 0/2] schd/fair: fix stalled cfs_rq->tg_load_avg_contrib
Date: Thu, 27 May 2021 16:19:08 +0200 [thread overview]
Message-ID: <CAKfTPtAK2fkzhzKA8iFT8cEcCG6Q=8WfLskPYADvTrQ=nF7kDA@mail.gmail.com> (raw)
In-Reply-To: <20210527122916.27683-1-vincent.guittot@linaro.org>
Hi Odin,
On Thu, 27 May 2021 at 14:29, Vincent Guittot
<vincent.guittot@linaro.org> wrote:
>
> Odin reported some fairness problem between cgroup because of stalled
> value in cfs_rq->tg_load_avg_contrib:
>
> https://lkml.org/lkml/2021/5/18/566
>
>
> 2 problems generated this situation:
> -1st: After propagating load in the hierarchy, load_sum can be null
> whereas load_avg isn't so the cfs_rq is removed whereas it still
> contribute to th tg's load
> -2nd: cfs_rq->tg_load_avg_contrib was not always updated after
> significant changes like becoming null because cfs_rq had already
> been updated when propagating a child load.
>
This series fixes the problem triggered by your 1st script on my test
machine. But could you confirm that this patchset also fixes the
problem on yours
Regards,
Vincent
>
> Vincent Guittot (2):
> sched/fair: keep load_avg and load_sum synced
> sched/fair: make sure to update tg contrib for blocked load
>
> kernel/sched/fair.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> --
> 2.17.1
>
next prev parent reply other threads:[~2021-05-27 14:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-27 12:29 [PATCH 0/2] schd/fair: fix stalled cfs_rq->tg_load_avg_contrib Vincent Guittot
2021-05-27 12:29 ` [PATCH 1/2] sched/fair: keep load_avg and load_sum synced Vincent Guittot
2021-05-27 13:05 ` Peter Zijlstra
2021-05-27 13:18 ` Vincent Guittot
2021-05-27 13:37 ` Peter Zijlstra
2021-05-27 13:40 ` kernel test robot
2021-05-31 10:40 ` [tip: sched/urgent] sched/fair: Keep " tip-bot2 for Vincent Guittot
2021-05-27 12:29 ` [PATCH 2/2] sched/fair: make sure to update tg contrib for blocked load Vincent Guittot
2021-05-31 10:40 ` [tip: sched/urgent] sched/fair: Make " tip-bot2 for Vincent Guittot
2021-05-27 14:19 ` Vincent Guittot [this message]
2021-05-27 14:24 ` [PATCH 0/2] schd/fair: fix stalled cfs_rq->tg_load_avg_contrib Odin Ugedal
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