From: Michal Hocko <mhocko@kernel.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Tim Hockin <thockin@hockin.org>, Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
kernel-team@fb.com, David Rientjes <rientjes@google.com>,
Linux MM <linux-mm@kvack.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Andrew Morton <akpm@linux-foundation.org>,
Cgroups <cgroups@vger.kernel.org>,
linux-doc@vger.kernel.org,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [v8 0/4] cgroup-aware OOM killer
Date: Mon, 2 Oct 2017 14:24:34 +0200 [thread overview]
Message-ID: <20171002122434.llbaarb6yw3o3mx3@dhcp22.suse.cz> (raw)
In-Reply-To: <CALvZod7iaOEeGmDJA0cZvJWpuzc-hMRn3PG2cfzcMniJtAjKqA@mail.gmail.com>
On Sun 01-10-17 16:29:48, Shakeel Butt wrote:
> >
> > Going back to Michal's example, say the user configured the following:
> >
> > root
> > / \
> > A D
> > / \
> > B C
> >
> > A global OOM event happens and we find this:
> > - A > D
> > - B, C, D are oomgroups
> >
> > What the user is telling us is that B, C, and D are compound memory
> > consumers. They cannot be divided into their task parts from a memory
> > point of view.
> >
> > However, the user doesn't say the same for A: the A subtree summarizes
> > and controls aggregate consumption of B and C, but without groupoom
> > set on A, the user says that A is in fact divisible into independent
> > memory consumers B and C.
> >
> > If we don't have to kill all of A, but we'd have to kill all of D,
> > does it make sense to compare the two?
> >
>
> I think Tim has given very clear explanation why comparing A & D makes
> perfect sense. However I think the above example, a single user system
> where a user has designed and created the whole hierarchy and then
> attaches different jobs/applications to different nodes in this
> hierarchy, is also a valid scenario.
Yes and nobody is disputing that, really. I guess the main disconnect
here is that different people want to have more detailed control over
the victim selection while the patchset tries to handle the most
simplistic scenario when a no userspace control over the selection is
required. And I would claim that this will be a last majority of setups
and we should address it first.
A more fine grained control needs some more thinking to come up with a
sensible and long term sustainable API. Just look back and see at the
oom_score_adj story and how it ended up unusable in the end (well apart
from never/always kill corner cases). Let's not repeat that again now.
I strongly believe that we can come up with something - be it priority
based, BFP based or module based selection. But let's start simple with
the most basic scenario first with a most sensible semantic implemented.
I believe the latest version (v9) looks sensible from the semantic point
of view and we should focus on making it into a mergeable shape.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-10-02 12:24 UTC|newest]
Thread overview: 78+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 13:17 [v8 0/4] cgroup-aware OOM killer Roman Gushchin
2017-09-11 13:17 ` [v8 1/4] mm, oom: refactor the oom_kill_process() function Roman Gushchin
2017-09-11 20:51 ` David Rientjes
2017-09-14 13:42 ` Michal Hocko
2017-09-11 13:17 ` [v8 2/4] mm, oom: cgroup-aware OOM killer Roman Gushchin
2017-09-13 20:46 ` David Rientjes
2017-09-13 21:59 ` Roman Gushchin
2017-09-11 13:17 ` [v8 3/4] mm, oom: add cgroup v2 mount option for " Roman Gushchin
2017-09-11 20:48 ` David Rientjes
2017-09-12 20:01 ` Roman Gushchin
2017-09-12 20:23 ` David Rientjes
2017-09-13 12:23 ` Michal Hocko
2017-09-11 13:17 ` [v8 4/4] mm, oom, docs: describe the " Roman Gushchin
2017-09-11 20:44 ` [v8 0/4] " David Rientjes
2017-09-13 12:29 ` Michal Hocko
2017-09-13 20:46 ` David Rientjes
2017-09-14 13:34 ` Michal Hocko
2017-09-14 20:07 ` David Rientjes
2017-09-13 21:56 ` Roman Gushchin
2017-09-14 13:40 ` Michal Hocko
2017-09-14 16:05 ` Roman Gushchin
2017-09-15 10:58 ` Michal Hocko
2017-09-15 15:23 ` Roman Gushchin
2017-09-15 19:55 ` David Rientjes
2017-09-15 21:08 ` Roman Gushchin
2017-09-18 6:20 ` Michal Hocko
2017-09-18 15:02 ` Roman Gushchin
2017-09-21 8:30 ` David Rientjes
2017-09-19 20:54 ` David Rientjes
2017-09-20 22:24 ` Roman Gushchin
2017-09-21 8:27 ` David Rientjes
2017-09-18 6:16 ` Michal Hocko
2017-09-19 20:51 ` David Rientjes
2017-09-18 6:14 ` Michal Hocko
2017-09-20 21:53 ` Roman Gushchin
2017-09-25 12:24 ` Michal Hocko
2017-09-25 17:00 ` Johannes Weiner
2017-09-25 18:15 ` Roman Gushchin
2017-09-25 20:25 ` Michal Hocko
2017-09-26 10:59 ` Roman Gushchin
2017-09-26 11:21 ` Michal Hocko
2017-09-26 12:13 ` Roman Gushchin
2017-09-26 13:30 ` Michal Hocko
2017-09-26 17:26 ` Johannes Weiner
2017-09-27 3:37 ` Tim Hockin
2017-09-27 7:43 ` Michal Hocko
2017-09-27 10:19 ` Roman Gushchin
2017-09-27 15:35 ` Tim Hockin
2017-09-27 16:23 ` Roman Gushchin
2017-09-27 18:11 ` Tim Hockin
2017-10-01 23:29 ` Shakeel Butt
2017-10-02 11:56 ` Tetsuo Handa
2017-10-02 12:24 ` Michal Hocko [this message]
2017-10-02 12:47 ` Roman Gushchin
2017-10-02 14:29 ` Michal Hocko
2017-10-02 19:00 ` Shakeel Butt
2017-10-02 19:28 ` Michal Hocko
2017-10-02 19:45 ` Shakeel Butt
2017-10-02 19:56 ` Michal Hocko
2017-10-02 20:00 ` Tim Hockin
2017-10-02 20:08 ` Michal Hocko
2017-10-02 20:20 ` Shakeel Butt
2017-10-02 20:24 ` Shakeel Butt
2017-10-02 20:34 ` Johannes Weiner
2017-10-02 20:55 ` Michal Hocko
2017-09-25 22:21 ` David Rientjes
2017-09-26 8:46 ` Michal Hocko
2017-09-26 21:04 ` David Rientjes
2017-09-27 7:37 ` Michal Hocko
2017-09-27 9:57 ` Roman Gushchin
2017-09-21 14:21 ` Johannes Weiner
2017-09-21 21:17 ` David Rientjes
2017-09-21 21:51 ` Johannes Weiner
2017-09-22 20:53 ` David Rientjes
2017-09-22 15:44 ` Tejun Heo
2017-09-22 20:39 ` David Rientjes
2017-09-22 21:05 ` Tejun Heo
2017-09-23 8:16 ` David Rientjes
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