linux-kernel - Re: [PATCH 6/5] oom, oom_reaper: disable oom

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Message-ID: <20160217113316.GD29196@dhcp22.suse.cz>
Date:	Wed, 17 Feb 2016 12:33:16 +0100
From:	Michal Hocko <mhocko@...nel.org>
To:	Tetsuo Handa <penguin-kernel@...ove.SAKURA.ne.jp>
Cc:	akpm@...ux-foundation.org, rientjes@...gle.com, mgorman@...e.de,
	oleg@...hat.com, torvalds@...ux-foundation.org, hughd@...gle.com,
	andrea@...nel.org, riel@...hat.com, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 6/5] oom, oom_reaper: disable oom_reaper for

On Wed 17-02-16 19:41:53, Tetsuo Handa wrote:
> Michal Hocko wrote:
> > Hi Andrew,
> > although this can be folded into patch 5
> > (mm-oom_reaper-implement-oom-victims-queuing.patch) I think it would be
> > better to have it separate and revert after we sort out the proper
> > oom_kill_allocating_task behavior or handle exclusion at oom_reaper
> > level.
> 
> What a rough workaround. sysctl_oom_kill_allocating_task == 1 does not
> always mean we must skip OOM reaper, for OOM-unkillable callers take
> sysctl_oom_kill_allocating_task == 0 path.

Yes it is indeed rough but also shouldn't add new issues. I consider
oom_kill_allocating_task as a borderline which can be sorted out later.
So while I do not like workarounds like this in general I would rather
go with obvious code first before going for more complex solutions.

> I've just posted a patchset which allows you to merge the OOM reaper
> without correcting problems found in "[PATCH 3/5] oom: clear TIF_MEMDIE
> after oom_reaper managed to unmap the address space" and "[PATCH 5/5]
> mm, oom_reaper: implement OOM victims queuing".

I will try to look at your patches but the series seems unnecessarily
heavy to be a pre-requisite for the oom_reaper.

Thanks!
-- 
Michal Hocko
SUSE Labs