From: David Rientjes <rientjes@google.com>
To: Shakeel Butt <shakeelb@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] memcg: enable memcg oom-kill for __GFP_NOFAIL
Date: Thu, 25 Feb 2021 13:36:06 -0800 (PST) [thread overview]
Message-ID: <f9a2aff-727b-445c-f6bd-613fc8725a@google.com> (raw)
In-Reply-To: <20210223204337.2785120-1-shakeelb@google.com>
On Tue, 23 Feb 2021, Shakeel Butt wrote:
> In the era of async memcg oom-killer, the commit a0d8b00a3381 ("mm:
> memcg: do not declare OOM from __GFP_NOFAIL allocations") added the code
> to skip memcg oom-killer for __GFP_NOFAIL allocations. The reason was
> that the __GFP_NOFAIL callers will not enter aync oom synchronization
> path and will keep the task marked as in memcg oom. At that time the
> tasks marked in memcg oom can bypass the memcg limits and the oom
> synchronization would have happened later in the later userspace
> triggered page fault. Thus letting the task marked as under memcg oom
> bypass the memcg limit for arbitrary time.
>
> With the synchronous memcg oom-killer (commit 29ef680ae7c21 ("memcg,
> oom: move out_of_memory back to the charge path")) and not letting the
> task marked under memcg oom to bypass the memcg limits (commit
> 1f14c1ac19aa4 ("mm: memcg: do not allow task about to OOM kill to bypass
> the limit")), we can again allow __GFP_NOFAIL allocations to trigger
> memcg oom-kill. This will make memcg oom behavior closer to page
> allocator oom behavior.
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
Acked-by: David Rientjes <rientjes@google.com>
prev parent reply other threads:[~2021-02-25 21:36 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 20:43 [PATCH] memcg: enable memcg oom-kill for __GFP_NOFAIL Shakeel Butt
2021-02-24 9:14 ` Michal Hocko
2021-02-24 20:38 ` Johannes Weiner
2021-02-25 21:36 ` David Rientjes [this message]
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