linux-kernel - Re: [PATCH] mm: Throttle allocators when failing reclaim over memory.high

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Message-ID: <20190201191636.GA17391@chrisdown.name>
Date:   Fri, 1 Feb 2019 14:16:36 -0500
From:   Chris Down <chris@...isdown.name>
To:     Michal Hocko <mhocko@...nel.org>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Johannes Weiner <hannes@...xchg.org>,
        Tejun Heo <tj@...nel.org>, Roman Gushchin <guro@...com>,
        linux-kernel@...r.kernel.org, cgroups@...r.kernel.org,
        linux-mm@...ck.org, kernel-team@...com
Subject: Re: [PATCH] mm: Throttle allocators when failing reclaim over
 memory.high

Michal Hocko writes:
>How does this play wit the actual OOM when the user expects oom to
>resolve the situation because the reclaim is futile and there is nothing
>reclaimable except for killing a process?

In addition to what Johannes said, this doesn't impede OOM in the case of 
global system starvation (eg. in the case that all major consumers of memory 
are allocator throttling). In that case nothing unusual will happen, since the 
task's state is TASK_KILLABLE rather than TASK_UNINTERRUPTIBLE, and we will 
exit out of mem_cgroup_handle_over_high as quickly as possible.