linux-kernel - Re: [PATCH] mm,oom: Re-enable OOM killer using timers.

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Message-ID: <alpine.DEB.2.10.1601211513550.9813@chino.kir.corp.google.com>
Date:	Thu, 21 Jan 2016 15:15:35 -0800 (PST)
From:	David Rientjes <rientjes@...gle.com>
To:	Tetsuo Handa <penguin-kernel@...ove.sakura.ne.jp>
cc:	hannes@...xchg.org, mhocko@...nel.org, akpm@...ux-foundation.org,
	mgorman@...e.de, torvalds@...ux-foundation.org, oleg@...hat.com,
	hughd@...gle.com, andrea@...nel.org, riel@...hat.com,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] mm,oom: Re-enable OOM killer using timers.

On Thu, 21 Jan 2016, Tetsuo Handa wrote:

> I consider phases for managing system-wide OOM events as follows.
> 
>   (1) Design and use a system with appropriate memory capacity in mind.
> 
>   (2) When (1) failed, the OOM killer is invoked. The OOM killer selects
>       an OOM victim and allow that victim access to memory reserves by
>       setting TIF_MEMDIE to it.
> 
>   (3) When (2) did not solve the OOM condition, start allowing all tasks
>       access to memory reserves by your approach.
> 
>   (4) When (3) did not solve the OOM condition, start selecting more OOM
>       victims by my approach.
> 
>   (5) When (4) did not solve the OOM condition, trigger the kernel panic.
> 

This was all mentioned previously, and I suggested that the panic only 
occur when memory reserves have been depleted, otherwise there is still 
the potential for the livelock to be solved.  That is a patch that would 
apply today, before any of this work, since we never want to loop 
endlessly in the page allocator when memory reserves are fully depleted.

This is all really quite simple.