From: David Hildenbrand <david@redhat.com>
To: 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
Cc: felipe.franciosi@nutanix.com
Subject: Re: [RFC PATCH] mm, oom: introduce vm.sacrifice_hugepage_on_oom
Date: Wed, 17 Feb 2021 10:09:58 +0100 [thread overview]
Message-ID: <dc18e98e-2467-bb36-7f78-d7003d9aa5f9@redhat.com> (raw)
In-Reply-To: <20210216030713.79101-1-eiichi.tsukata@nutanix.com>
On 16.02.21 04:07, Eiichi Tsukata wrote:
> Hugepages can be preallocated to avoid unpredictable allocation latency.
> If we run into 4k page shortage, the kernel can trigger OOM even though
> there were free hugepages. When OOM is triggered by user address page
> fault handler, we can use oom notifier to free hugepages in user space
> but if it's triggered by memory allocation for kernel, there is no way
> to synchronously handle it in user space.
>
> This patch introduces a new sysctl vm.sacrifice_hugepage_on_oom. If
> enabled, it first tries to free a hugepage if available before invoking
> the oom-killer. The default value is disabled not to change the current
> behavior.
In addition to the other comments, some more thoughts:
What if you're low on kernel memory but you end up freeing huge pages
residing in ZONE_MOVABLE? IOW, this is not zone aware.
--
Thanks,
David / dhildenb
prev parent reply other threads:[~2021-02-17 9:10 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
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 [this message]
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