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From:   Yosry Ahmed <yosryahmed@google.com>
Date:   Fri, 28 Apr 2023 06:05:12 -0700
Message-ID: <CAJD7tkZJK7yYueixaYh4J1vpMf+WYkDj-sm7fsfbv-irXQ_9Wg@mail.gmail.com>
Subject: Re: [PATCH 2/2] memcg: dump memory.stat during cgroup OOM for v1
To:     Michal Hocko <mhocko@suse.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Muchun Song <muchun.song@linux.dev>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Steven Rostedt <rostedt@goodmis.org>,
        Petr Mladek <pmladek@suse.com>, Chris Li <chrisl@kernel.org>,
        cgroups@vger.kernel.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
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On Fri, Apr 28, 2023 at 2:44=E2=80=AFAM Michal Hocko <mhocko@suse.com> wrot=
e:
>
> On Thu 27-04-23 15:12:46, Yosry Ahmed wrote:
> [...]
> > However, I still think this change is valuable. Like you mentioned,
> > the OOM log is not set in stone, but we shouldn't just change it for
> > no reason. In this case, for cgroup v1 users, the OOM log changed for
> > no reason beyond a side effect of another patch. Upon upgrading our
> > kernel we noticed the behavior change. This patch restores the old
> > behavior without any cost really, and it makes the code a tiny bit
> > more consistent.
>
> Fair enough. Just make sure you go into more details about why this is
> causing problems/inconveniences. I am slightly worried this might cause
> problems to other people who would like to have the same report for both
> v1 and v2 so we should at least have some solid argumetns to revert
> rather than "it used has changed and we liked it more that way".
>
> I personally do not care all that much. It kinda sucks to dump counters
> that are not tracked or fully tracked in v1 because that can mislead
> people and that would be a bigger problem from my POV.

Great point, let me send a v2 rephrasing the commit log of this patch
and adding the Ack's on the first one.

Thanks Michal!

> --
> Michal Hocko
> SUSE Labs