linux-kernel - Re: [RFC PATCH 0/5] mm: Select victim memcg using BPF_OOM

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Message-ID: <ZMInlGaW90Uw1hSo@dhcp22.suse.cz>
Date:   Thu, 27 Jul 2023 10:15:16 +0200
From:   Michal Hocko <mhocko@...e.com>
To:     Chuyi Zhou <zhouchuyi@...edance.com>
Cc:     hannes@...xchg.org, roman.gushchin@...ux.dev, ast@...nel.org,
        daniel@...earbox.net, andrii@...nel.org, bpf@...r.kernel.org,
        linux-kernel@...r.kernel.org, wuyun.abel@...edance.com,
        robin.lu@...edance.com
Subject: Re: [RFC PATCH 0/5] mm: Select victim memcg using BPF_OOM_POLICY

On Thu 27-07-23 15:36:27, Chuyi Zhou wrote:
> This patchset tries to add a new bpf prog type and use it to select
> a victim memcg when global OOM is invoked. The mainly motivation is
> the need to customizable OOM victim selection functionality so that
> we can protect more important app from OOM killer.

This is rather modest to give an idea how the whole thing is supposed to
work. I have looked through patches very quickly but there is no overall
design described anywhere either.

Please could you give us a high level design description and reasoning
why certain decisions have been made? e.g. why is this limited to the
global oom sitation, why is the BPF program forced to operate on memcgs
as entities etc...
Also it would be very helpful to call out limitations of the BPF
program, if there are any.

Thanks!
-- 
Michal Hocko
SUSE Labs