From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm, memory_hotplug: do not back off draining pcp free pages from kworker context
Date: Mon, 18 Sep 2017 20:38:22 -0700 [thread overview]
Message-ID: <20170919033821.GR378890@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <20170831053342.fo7x4hnhicxikme4@dhcp22.suse.cz>
Hello, Sorry about the delay.
On Thu, Aug 31, 2017 at 07:33:42AM +0200, Michal Hocko wrote:
> > > Michal, are you sure that this patch does not cause deadlock?
> > >
> > > As shown in "[PATCH] mm: Use WQ_HIGHPRI for mm_percpu_wq." thread, currently work
> > > items on mm_percpu_wq seem to be blocked by other work items not on mm_percpu_wq.
IIUC that wasn't a deadlock but more a legitimate starvation from too
many tasks trying to reclaim directly.
> > But we have a rescuer so we should make a forward progress eventually.
> > Or am I missing something. Tejun, could you have a look please?
>
> ping... I would really appreaciate if you could double check my thinking
> Tejun. This is a tricky area and I would like to prevent further subtle
> issues here.
So, this shouldn't be an issue. This may get affected by direct
reclaim frenzy but it's only a small piece of the whole symptom and we
gotta fix that at the source.
Thanks.
--
tejun
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next prev parent reply other threads:[~2017-09-19 3:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-28 9:33 [PATCH] mm, memory_hotplug: do not back off draining pcp free pages from kworker context Michal Hocko
2017-08-28 22:33 ` Andrew Morton
2017-08-29 11:20 ` Tetsuo Handa
2017-08-29 11:28 ` Michal Hocko
2017-08-31 5:33 ` Michal Hocko
2017-09-19 3:38 ` Tejun Heo [this message]
2017-09-19 9:45 ` Michal Hocko
2017-09-19 18:57 ` Tejun Heo
2017-08-29 13:53 ` Michal Hocko
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