From: Michal Hocko <mhocko@kernel.org>
To: Vladimir Davydov <vdavydov@virtuozzo.com>
Cc: David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] mm: oom: deduplicate victim selection code for memcg and global oom
Date: Fri, 1 Jul 2016 13:18:36 +0200 [thread overview]
Message-ID: <20160701111836.GD10813@dhcp22.suse.cz> (raw)
In-Reply-To: <20160628161642.GA30658@esperanza>
On Tue 28-06-16 19:16:42, Vladimir Davydov wrote:
> On Mon, Jun 27, 2016 at 05:14:31PM -0700, David Rientjes wrote:
> > On Mon, 27 Jun 2016, Vladimir Davydov wrote:
> >
> > > When selecting an oom victim, we use the same heuristic for both memory
> > > cgroup and global oom. The only difference is the scope of tasks to
> > > select the victim from. So we could just export an iterator over all
> > > memcg tasks and keep all oom related logic in oom_kill.c, but instead we
> > > duplicate pieces of it in memcontrol.c reusing some initially private
> > > functions of oom_kill.c in order to not duplicate all of it. That looks
> > > ugly and error prone, because any modification of select_bad_process
> > > should also be propagated to mem_cgroup_out_of_memory.
> > >
> > > Let's rework this as follows: keep all oom heuristic related code
> > > private to oom_kill.c and make oom_kill.c use exported memcg functions
> > > when it's really necessary (like in case of iterating over memcg tasks).
> > >
> >
> > I don't know how others feel, but this actually turns out harder to read
> > for me with all the extra redirection with minimal savings (a few dozen
> > lines of code).
>
> Well, if you guys find the code difficult to read after this patch,
> let's leave it as is. Sorry for the noise.
I didn't get to read the patch yet and will be offline for next few
days. I will have a look later. I believe that this is an area which is
worth cleaning up and get rid of duplication. Whether your approach is
right one I cannot tell right now. I found the previous version harder
to read than a simpler approach I have posted. Anyway I will have a look
later. And this is definitelly not a noise...
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2016-07-01 11:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-27 16:39 Vladimir Davydov
2016-06-28 0:14 ` David Rientjes
2016-06-28 16:16 ` Vladimir Davydov
2016-07-01 11:18 ` Michal Hocko [this message]
2016-07-21 12:41 ` Johannes Weiner
2016-07-23 14:49 ` Vladimir Davydov
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