From: Johannes Weiner <hannes@cmpxchg.org>
To: Michal Hocko <mhocko@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Shakeel Butt <shakeelb@google.com>,
Roman Gushchin <roman.gushchin@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
linux-mm@kvack.org
Subject: Re: [PATCH] memcg: drop kmem.limit_in_bytes
Date: Fri, 7 Jul 2023 09:50:48 -0400 [thread overview]
Message-ID: <20230707135048.GA214771@cmpxchg.org> (raw)
In-Reply-To: <ZKe5wxdbvPi5Cwd7@dhcp22.suse.cz>
On Fri, Jul 07, 2023 at 09:07:47AM +0200, Michal Hocko wrote:
> From b1bbc63b6baff9c5aaf30393cec29112b3abca25 Mon Sep 17 00:00:00 2001
> From: Michal Hocko <mhocko@suse.com>
> Date: Tue, 4 Jul 2023 13:38:11 +0200
> Subject: [PATCH] memcg: drop kmem.limit_in_bytes
>
> kmem.limit_in_bytes (v1 way to limit kernel memory usage) has been
> deprecated since 58056f77502f ("memcg, kmem: further deprecate
> kmem.limit_in_bytes") merged in 5.16. We haven't heard about any
> serious users since then but it seems that the mere presence of the file
> is causing more harm thatn good. We (SUSE) have had several bug reports
> from customers where Docker based containers started to fail because a
> write to kmem.limit_in_bytes has failed.
>
> This was unexpected because runc code only expects ENOENT (kmem
> disabled) or EBUSY (tasks already running within cgroup). So a new error
> code was unexpected and the whole container startup failed. This has
> been later addressed by
> https://github.com/opencontainers/runc/commit/52390d68040637dfc77f9fda6bbe70952423d380
> so current Docker runtimes do not suffer from the problem anymore. There
> are still older version of Docker in use and likely hard to get rid of
> completely.
>
> Address this by wiping out the file completely and effectively get back
> to pre 4.5 era and CONFIG_MEMCG_KMEM=n configuration.
>
> I would recommend backporting to stable trees which have picked up
> 58056f77502f ("memcg, kmem: further deprecate kmem.limit_in_bytes").
>
> Cc: stable
> Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
next prev parent reply other threads:[~2023-07-07 13:50 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-04 11:52 Michal Hocko
2023-07-05 5:13 ` Shakeel Butt
2023-07-05 13:44 ` Johannes Weiner
2023-07-07 7:07 ` Michal Hocko
2023-07-07 13:50 ` Johannes Weiner [this message]
2023-07-07 16:40 ` Roman Gushchin
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