From: Michal Hocko <mhocko@suse.com>
To: David Rientjes <rientjes@google.com>
Cc: Eiichi Tsukata <eiichi.tsukata@nutanix.com>,
corbet@lwn.net, mike.kravetz@oracle.com, mcgrof@kernel.org,
keescook@chromium.org, yzaikin@google.com,
akpm@linux-foundation.org, linux-doc@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
linux-fsdevel@vger.kernel.org, felipe.franciosi@nutanix.com
Subject: Re: [RFC PATCH] mm, oom: introduce vm.sacrifice_hugepage_on_oom
Date: Wed, 17 Feb 2021 08:54:55 +0100 [thread overview]
Message-ID: <YCzLz0QmwYLfqvu0@dhcp22.suse.cz> (raw)
In-Reply-To: <b821f4de-3260-f6e2-469f-65ccfa699bb7@google.com>
On Tue 16-02-21 13:53:12, David Rientjes wrote:
> On Tue, 16 Feb 2021, Michal Hocko wrote:
[...]
> > Overall, I am not really happy about this feature even when above is
> > fixed, but let's hear more the actual problem first.
>
> Shouldn't this behavior be possible as an oomd plugin instead, perhaps
> triggered by psi? I'm not sure if oomd is intended only to kill something
> (oomkilld? lol) or if it can be made to do sysadmin level behavior, such
> as shrinking the hugetlb pool, to solve the oom condition.
It should be under control of an admin who knows what the pool is
preallocated for and whether a decrease (e.g. a temporal one) is
tolerable.
> If so, it seems like we want to do this at the absolute last minute. In
> other words, reclaim has failed to free memory by other means so we would
> like to shrink the hugetlb pool. (It's the reason why it's implemented as
> a predecessor to oom as opposed to part of reclaim in general.)
>
> Do we have the ability to suppress the oom killer until oomd has a chance
> to react in this scenario?
We don't and I do not think we want to bind the kernel oom behavior to
any userspace process. We have extensively discussed things like this in
the past IIRC.
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-02-17 7:55 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-16 3:07 [RFC PATCH] mm, oom: introduce vm.sacrifice_hugepage_on_oom Eiichi Tsukata
2021-02-16 8:12 ` Michal Hocko
2021-02-16 21:53 ` David Rientjes
2021-02-17 7:54 ` Michal Hocko [this message]
2021-02-17 14:59 ` Shakeel Butt
2021-02-16 22:30 ` Mike Kravetz
2021-02-17 7:57 ` Michal Hocko
2021-02-17 10:42 ` Eiichi Tsukata
2021-02-17 12:31 ` Michal Hocko
2021-02-17 12:40 ` Michal Hocko
2021-02-18 12:22 ` Eiichi Tsukata
2021-02-18 12:39 ` Chris Down
2021-02-16 13:38 ` Chris Down
2021-02-17 9:09 ` David Hildenbrand
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