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

From: David Rientjes
Date: Thu Jan 21 2016 - 18:15:41 EST


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.