Re: [PATCH v4] mm/page_alloc: bail out on fatal signal during reclaim/compaction retry attempt

From: Michal Hocko
Date: Mon May 31 2021 - 07:33:42 EST


On Thu 20-05-21 15:29:01, Aaron Tomlin wrote:
> A customer experienced a low-memory situation and decided to issue a
> SIGKILL (i.e. a fatal signal). Instead of promptly terminating as one
> would expect, the aforementioned task remained unresponsive.
>
> Further investigation indicated that the task was "stuck" in the
> reclaim/compaction retry loop. Now, it does not make sense to retry
> compaction when a fatal signal is pending.

Is this really true in general? The memory reclaim is retried even when
fatal signals are pending. Why should be compaction different? I do
agree that retrying way too much is bad but is there any reason why this
special case doesn't follow the max retry logic?
--
Michal Hocko
SUSE Labs