From: Michal Hocko <mhocko@kernel.org>
To: David Rientjes <rientjes@google.com>
Cc: Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Vladimir Davydov <vdavydov.dev@gmail.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Tejun Heo <tj@kernel.org>,
kernel-team@fb.com, cgroups@vger.kernel.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RESEND v12 0/6] cgroup-aware OOM killer
Date: Tue, 31 Oct 2017 08:54:08 +0100 [thread overview]
Message-ID: <20171031075408.67au22uk6dkpu7vv@dhcp22.suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.10.1710301430170.105449@chino.kir.corp.google.com>
On Mon 30-10-17 14:36:39, David Rientjes wrote:
> On Fri, 27 Oct 2017, Roman Gushchin wrote:
>
> > The thing is that the hierarchical approach (as in v8), which are you pushing,
> > has it's own limitations, which we've discussed in details earlier. There are
> > reasons why v12 is different, and we can't really simple go back. I mean if
> > there are better ideas how to resolve concerns raised in discussions around v8,
> > let me know, but ignoring them is not an option.
> >
>
> I'm not ignoring them, I have stated that we need the ability to protect
> important cgroups on the system without oom disabling all attached
> processes. If that is implemented as a memory.oom_score_adj with the same
> semantics as /proc/pid/oom_score_adj, i.e. a proportion of available
> memory (the limit), it can also address the issues pointed out with the
> hierarchical approach in v8.
No it cannot and it would be a terrible interface to have as well. You
do not want to permanently tune oom_score_adj to compensate for
structural restrictions on the hierarchy.
> If this is not the case, could you elaborate
> on what your exact concern is and why we do not care that users can
> completely circumvent victim selection by creating child cgroups for other
> controllers?
>
> Since the ability to protect important cgroups on the system may require a
> heuristic change, I think it should be solved now rather than constantly
> insisting that we can make this patchset complete later and in the
> meantime force the user to set all attached processes to be oom disabled.
I believe, and Roman has pointed that out as well already, that further
improvements can be implemented without changing user visible behavior
as and add-on. If you disagree then you better come with a solid proof
that all of us wrong and reasonable semantic cannot be achieved that
way.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-10-31 7:54 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-19 18:52 [RESEND v12 0/6] cgroup-aware OOM killer Roman Gushchin
2017-10-19 18:52 ` [RESEND v12 1/6] mm, oom: refactor the oom_kill_process() function Roman Gushchin
2017-10-19 18:52 ` [RESEND v12 2/6] mm: implement mem_cgroup_scan_tasks() for the root memory cgroup Roman Gushchin
2017-10-19 18:52 ` [RESEND v12 3/6] mm, oom: cgroup-aware OOM killer Roman Gushchin
2017-10-19 19:30 ` Michal Hocko
2017-10-31 15:04 ` Shakeel Butt
2017-10-31 15:29 ` Michal Hocko
2017-10-31 19:06 ` Michal Hocko
2017-10-31 19:13 ` Michal Hocko
2017-10-31 16:40 ` Johannes Weiner
2017-10-31 17:50 ` Shakeel Butt
2017-10-31 18:44 ` Johannes Weiner
2017-10-19 18:52 ` [RESEND v12 4/6] mm, oom: introduce memory.oom_group Roman Gushchin
2017-10-19 18:52 ` [RESEND v12 5/6] mm, oom: add cgroup v2 mount option for cgroup-aware OOM killer Roman Gushchin
2017-10-19 18:52 ` [RESEND v12 6/6] mm, oom, docs: describe the " Roman Gushchin
2017-10-19 19:45 ` [RESEND v12 0/6] " Johannes Weiner
2017-10-19 21:09 ` Michal Hocko
2017-10-23 0:24 ` David Rientjes
2017-10-23 11:49 ` Michal Hocko
2017-10-25 20:12 ` David Rientjes
2017-10-26 14:24 ` Johannes Weiner
2017-10-26 21:03 ` David Rientjes
2017-10-27 9:31 ` Roman Gushchin
2017-10-30 21:36 ` David Rientjes
2017-10-31 7:54 ` Michal Hocko [this message]
2017-10-31 22:21 ` David Rientjes
2017-11-01 7:37 ` Michal Hocko
2017-11-01 20:42 ` David Rientjes
2017-10-27 20:05 ` Johannes Weiner
2017-10-31 14:17 ` peter enderborg
2017-10-31 14:34 ` Michal Hocko
2017-10-31 15:07 ` peter enderborg
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