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From:   Shakeel Butt <shakeelb@google.com>
Date:   Fri, 22 May 2020 07:07:56 -0700
Message-ID: <CALvZod6ijEUKTXzi1oDV0R2HdU6bcxUn_zDigskuSPtzn-vw0g@mail.gmail.com>
Subject: Re: [PATCH] mm, memcg: unify reclaim retry limits with page allocator
To:     Chris Down <chris@chrisdown.name>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Cgroups <cgroups@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Kernel Team <kernel-team@fb.com>
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On Wed, May 20, 2020 at 9:32 AM Chris Down <chris@chrisdown.name> wrote:
>
> Reclaim retries have been set to 5 since the beginning of time in
> 66e1707bc346 ("Memory controller: add per cgroup LRU and reclaim").
> However, we now have a generally agreed-upon standard for page reclaim:
> MAX_RECLAIM_RETRIES (currently 16), added many years later in
> 0a0337e0d1d1 ("mm, oom: rework oom detection").
>
> In the absence of a compelling reason to declare an OOM earlier in memcg
> context than page allocator context, it seems reasonable to supplant
> MEM_CGROUP_RECLAIM_RETRIES with MAX_RECLAIM_RETRIES, making the page
> allocator and memcg internals more similar in semantics when reclaim
> fails to produce results, avoiding premature OOMs or throttling.
>
> Signed-off-by: Chris Down <chris@chrisdown.name>

Reviewed-by: Shakeel Butt <shakeelb@google.com>