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Date:   Thu, 1 Jun 2023 15:36:30 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Dan Schatzberg <schatzberg.dan@gmail.com>
Cc:     Tejun Heo <tj@kernel.org>, Chris Down <chris@chrisdown.name>,
        Zefan Li <lizefan.x@bytedance.com>,
        Jonathan Corbet <corbet@lwn.net>,
        "open list:CONTROL GROUP (CGROUP)" <cgroups@vger.kernel.org>,
        "open list:DOCUMENTATION" <linux-doc@vger.kernel.org>,
        open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] Documentation: Clarify usage of memory limits
Message-ID: <20230601193630.GA157732@cmpxchg.org>
References: <20230601183820.3839891-1-schatzberg.dan@gmail.com>
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In-Reply-To: <20230601183820.3839891-1-schatzberg.dan@gmail.com>
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On Thu, Jun 01, 2023 at 11:38:19AM -0700, Dan Schatzberg wrote:
> The existing documentation refers to memory.high as the "main mechanism
> to control memory usage." This seems incorrect to me - memory.high can
> result in reclaim pressure which simply leads to stalls unless some
> external component observes and actions on it (e.g. systemd-oomd can be
> used for this purpose). While this is feasible, users are unaware of
> this interaction and are led to believe that memory.high alone is an
> effective mechanism for limiting memory.
> 
> The documentation should recommend the use of memory.max as the
> effective way to enforce memory limits - it triggers reclaim and results
> in OOM kills by itself.
> 
> Signed-off-by: Dan Schatzberg <schatzberg.dan@gmail.com>

Yeah, this is quite stale. How this ended up working in practice is a
bit different from how we initially conceived it.

Thanks for updating it.

Acked-by: Johannes Weiner <hannes@cmpxchg.org>