From: Shakeel Butt <shakeelb@google.com>
To: peter enderborg <Peter.Enderborg@sony.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
Linux MM <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
Cgroups <cgroups@vger.kernel.org>,
David Rientjes <rientjes@google.com>,
LKML <linux-kernel@vger.kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Greg Thelen <gthelen@google.com>,
Dragos Sbirlea <dragoss@google.com>,
Priya Duraisamy <padmapriyad@google.com>
Subject: Re: [RFC] memory reserve for userspace oom-killer
Date: Wed, 21 Apr 2021 12:18:22 -0700 [thread overview]
Message-ID: <CALvZod5+5ycobmSt=NC3VJF4FRMFmBQEN7SQgipyTDbzHEbPUQ@mail.gmail.com> (raw)
In-Reply-To: <1f8d300b-9a8b-de09-6d5d-6a9c20c66d24@sony.com>
On Wed, Apr 21, 2021 at 11:46 AM <Peter.Enderborg@sony.com> wrote:
>
> On 4/21/21 8:28 PM, Shakeel Butt wrote:
> > On Wed, Apr 21, 2021 at 10:06 AM peter enderborg
> > <peter.enderborg@sony.com> wrote:
> >> On 4/20/21 3:44 AM, Shakeel Butt wrote:
> > [...]
> >> I think this is the wrong way to go.
> > Which one? Are you talking about the kernel one? We already talked out
> > of that. To decide to OOM, we need to look at a very diverse set of
> > metrics and it seems like that would be very hard to do flexibly
> > inside the kernel.
> You dont need to decide to oom, but when oom occurs you
> can take a proper action.
No, we want the flexibility to decide when to oom-kill. Kernel is very
conservative in triggering the oom-kill.
> >
[...]
> > Actually no. It is missing the flexibility to monitor metrics which a
> > user care and based on which they decide to trigger oom-kill. Not sure
> > how will watchdog replace psi/vmpressure? Userspace keeps petting the
> > watchdog does not mean that system is not suffering.
>
> The userspace should very much do what it do. But when it
> does not do what it should do, including kick the WD. Then
> the kernel kicks in and kill a pre defined process or as many
> as needed until the monitoring can start to kick and have the
> control.
>
Roman already suggested something similar (i.e. oom-killer core and
extended and core watching extended) but completely in userspace. I
don't see why we would want to do that in the kernel instead.
> >
> > In addition oom priorities change dynamically and changing it in your
> > system seems very hard. Cgroup awareness is missing too.
>
> Why is that hard? Moving a object in a rb-tree is as good it get.
>
It is a group of objects. Anyways that is implementation detail.
The message I got from this exchange is that we can have a watchdog
(userspace or kernel) to further improve the reliability of userspace
oom-killers.
next prev parent reply other threads:[~2021-04-21 19:18 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 1:44 [RFC] memory reserve for userspace oom-killer Shakeel Butt
2021-04-20 6:45 ` Michal Hocko
2021-04-20 16:04 ` Shakeel Butt
2021-04-21 7:16 ` Michal Hocko
2021-04-21 13:57 ` Shakeel Butt
2021-04-21 14:29 ` Michal Hocko
2021-04-22 12:33 ` [RFC PATCH] Android OOM helper proof of concept peter enderborg
2021-04-22 13:03 ` Michal Hocko
2021-05-05 0:37 ` [RFC] memory reserve for userspace oom-killer Shakeel Butt
2021-05-05 1:26 ` Suren Baghdasaryan
2021-05-05 2:45 ` Shakeel Butt
2021-05-05 2:59 ` Suren Baghdasaryan
2021-05-05 2:43 ` Hillf Danton
2021-04-20 19:17 ` Roman Gushchin
2021-04-20 19:36 ` Suren Baghdasaryan
2021-04-21 1:18 ` Shakeel Butt
2021-04-21 2:58 ` Roman Gushchin
2021-04-21 13:26 ` Shakeel Butt
2021-04-21 19:04 ` Roman Gushchin
2021-04-21 7:23 ` Michal Hocko
2021-04-21 14:13 ` Shakeel Butt
2021-04-21 17:05 ` peter enderborg
2021-04-21 18:28 ` Shakeel Butt
2021-04-21 18:46 ` Peter.Enderborg
2021-04-21 19:18 ` Shakeel Butt [this message]
2021-04-22 5:38 ` Peter.Enderborg
2021-04-22 14:27 ` Shakeel Butt
2021-04-22 15:41 ` Peter.Enderborg
2021-04-22 13:08 ` Michal Hocko
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