Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 9 Jun 2021 15:35:34 +0100
From:   Aaron Tomlin <atomlin@redhat.com>
To:     Michal Hocko <mhocko@suse.com>
Cc:     Waiman Long <llong@redhat.com>, Shakeel Butt <shakeelb@google.com>,
        Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vlastimil Babka <vbabka@suse.cz>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] mm/oom_kill: allow oom kill allocating task for
 non-global case
Message-ID: <20210609143534.v65qknfihqimiivd@ava.usersys.com>
References: <20210607163103.632681-1-atomlin@redhat.com>
 <c16893a9-35e2-7625-d7f3-83488f874040@redhat.com>
 <CALvZod4eUoquGTQ5AsWgbWTQyqtCNNwb-9+fRw_ZPavH-r9dbA@mail.gmail.com>
 <dc7f54eb-933e-5bbb-7959-815dfbfcc836@redhat.com>
 <YL5tqdw+iWLLavxV@dhcp22.suse.cz>
 <6d23ce58-4c4b-116a-6d74-c2cf4947492b@redhat.com>
 <YL51Tp/3jVHUrpuj@dhcp22.suse.cz>
 <YL57rLFwAo7EpYeH@dhcp22.suse.cz>
 <353d012f-e8d4-c54c-b33e-54737e1a0115@redhat.com>
 <YL8MjSteKeO7w0il@dhcp22.suse.cz>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <YL8MjSteKeO7w0il@dhcp22.suse.cz>
Precedence: bulk

On Tue 2021-06-08 08:22 +0200, Michal Hocko wrote:
> Is it possible the only eligible task has been killed and oom reaped
> already?

Yes, I suspect so; and I had a look at the vmcore, the task in the OOM
report is no longer present. Therefore, I suspect the task namely "node"
(i.e. PID 1703345) was OOM killed i.e. a SIGKILL was sent and was granted
access to memory reserves and selected/or choosen by the OOM reaper for
termination; the victim then raised a page fault that triggered yet
another "charge" in the memcg that exceeded the memory limit set on the
container; and since no other task in the memcg had a suitable OOM score
and the allocating task/or victim was "unkillable" i.e. already selected
for termination by the OOM reaper, we got the message: "Out of memory and
no killable processes...".


-- 
Aaron Tomlin