linux-kernel - Re: Let's talk about the elephant in the room - the Linux kernel's inability to gracefully handle low memory pressure

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Message-ID: <20190807211245.GA11071@cmpxchg.org>
Date:   Wed, 7 Aug 2019 17:12:45 -0400
From:   Johannes Weiner <hannes@...xchg.org>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Suren Baghdasaryan <surenb@...gle.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        "Artem S. Tashkinov" <aros@....com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-mm <linux-mm@...ck.org>
Subject: Re: Let's talk about the elephant in the room - the Linux kernel's
 inability to gracefully handle low memory pressure

On Wed, Aug 07, 2019 at 04:51:42PM -0400, Johannes Weiner wrote:
> Per default, the OOM killer will engage after 15 seconds of at least
> 80% memory pressure. These values are tunable via sysctls
> vm.thrashing_oom_period and vm.thrashing_oom_level.

Let's go with this:

Per default, the OOM killer will engage after 15 seconds of at least
80% memory pressure. From experience, at 80% the user is experiencing
multi-second reaction times. 15 seconds is chosen to be long enough to
not OOM kill a short-lived spike that might resolve itself, yet short
enough for users to not press the reset button just yet.