From: Tejun Heo <tj@kernel.org>
To: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: mhocko@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org,
mgorman@suse.de, vbabka@suse.cz
Subject: Re: [PATCH] mm: Use WQ_HIGHPRI for mm_percpu_wq.
Date: Fri, 1 Sep 2017 06:47:49 -0700 [thread overview]
Message-ID: <20170901134748.GC1599492@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <201709010707.ABI69774.OLSVMOOFHFQJtF@I-love.SAKURA.ne.jp>
Hello,
On Fri, Sep 01, 2017 at 07:07:25AM +0900, Tetsuo Handa wrote:
> cond_resched() from !PF_WQ_WORKER threads is sufficient for PF_WQ_WORKER threads to run.
> But cond_resched() is not sufficient for rescuer threads to start processing a pending work.
> An explicit scheduling (e.g. schedule_timeout_*()) by PF_WQ_WORKER threads is needed for
> rescuer threads to start processing a pending work.
I'm not even sure this is the case. Unless I'm mistaken, in your
workqueue dumps, the available workers couldn't even leave idle which
means that they likely didn't get scheduled at all. It looks like
genuine multi minute starvation by competing direct reclaims. What's
the load number like while these events are in progress?
Thanks.
--
tejun
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next prev parent reply other threads:[~2017-09-01 13:47 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1503921210-4603-1-git-send-email-penguin-kernel@I-love.SAKURA.ne.jp>
2017-08-28 12:10 ` Michal Hocko
2017-08-28 17:06 ` Tejun Heo
2017-08-28 22:15 ` Tetsuo Handa
2017-08-28 23:02 ` Tejun Heo
2017-08-28 23:09 ` Tejun Heo
2017-08-29 11:14 ` Tetsuo Handa
2017-08-29 14:38 ` Tejun Heo
2017-08-29 21:41 ` Tejun Heo
2017-08-30 13:51 ` Tetsuo Handa
2017-08-31 1:46 ` Tejun Heo
2017-08-31 14:52 ` Tetsuo Handa
2017-08-31 15:25 ` Michal Hocko
2017-08-31 22:07 ` Tetsuo Handa
2017-09-01 13:47 ` Tejun Heo [this message]
2017-09-01 14:29 ` Tetsuo Handa
2017-08-29 13:33 ` Michal Hocko
2017-08-29 14:33 ` Tejun Heo
2017-08-29 20:29 ` Tetsuo Handa
2017-08-30 6:40 ` Michal Hocko
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