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From: Burt Holzman <burt@fnal.gov>
Subject: Re: OOM notification for cgroupsv1 broken in 4.19
Date: Fri, 21 Dec 2018 17:33:17 +0000
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 <20181221153302.GB6410@dhcp22.suse.cz>
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To: Michal Hocko <mhocko@kernel.org>
Cc: "hannes@cmpxchg.org" <hannes@cmpxchg.org>, "vdavydov.dev@gmail.com" <vdavydov.dev@gmail.com>, "cgroups@vger.kernel.org" <cgroups@vger.kernel.org>, "linux-mm@kvack.org" <linux-mm@kvack.org>


> On Dec 21, 2018, at 9:33 AM, Michal Hocko <mhocko@kernel.org> wrote:
>=20
> On Fri 21-12-18 14:49:38, Burt Holzman wrote:
>> Hi,
>>=20
>> This patch: 29ef680ae7c21110af8e6416d84d8a72fc147b14
>> [PATCH] memcg, oom: move out_of_memory back to the charge path
>>=20
>> has broken the eventfd notification for cgroups-v1. This is because=20
>> mem_cgroup_oom_notify() is called only in mem_cgroup_oom_synchronize and=
=20
>> not with the new, additional call to mem_cgroup_out_of_memory in the=20
>> charge path.
>=20
> Yes, you are right and this is a clear regression. Does the following
> patch fixes the issue for you? I am not super happy about the code
> duplication but I wasn't able to separate this out from
> mem_cgroup_oom_synchronize because that one has to handle the oom_killer
> disabled case which is not the case in the charge path because we simply
> back off and hand over to mem_cgroup_oom_synchronize in that case.

Hi Michal,

Thanks for the quick response & patch. I can confirm that with this patch t=
he notification is working for my sample test case.

- B