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Date:   Tue, 28 Mar 2023 14:50:21 -0400
From:   Johannes Weiner <hannes@cmpxchg.org>
To:     Yosry Ahmed <yosryahmed@google.com>
Cc:     Tejun Heo <tj@kernel.org>, Josef Bacik <josef@toxicpanda.com>,
        Jens Axboe <axboe@kernel.dk>,
        Zefan Li <lizefan.x@bytedance.com>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Muchun Song <muchun.song@linux.dev>,
        Andrew Morton <akpm@linux-foundation.org>,
        Michal =?iso-8859-1?Q?Koutn=FD?= <mkoutny@suse.com>,
        Vasily Averin <vasily.averin@linux.dev>,
        cgroups@vger.kernel.org, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-mm@kvack.org,
        bpf@vger.kernel.org
Subject: Re: [PATCH v1 9/9] memcg: do not modify rstat tree for zero updates
Message-ID: <ZCM27V3Z/Z9TD2zL@cmpxchg.org>
References: <20230328061638.203420-1-yosryahmed@google.com>
 <20230328061638.203420-10-yosryahmed@google.com>
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On Tue, Mar 28, 2023 at 06:16:38AM +0000, Yosry Ahmed wrote:
> In some situations, we may end up calling memcg_rstat_updated() with a
> value of 0, which means the stat was not actually updated. An example is
> if we fail to reclaim any pages in shrink_folio_list().
> 
> Do not add the cgroup to the rstat updated tree in this case, to avoid
> unnecessarily flushing it.
> 
> Signed-off-by: Yosry Ahmed <yosryahmed@google.com>

Acked-by: Johannes Weiner <hannes@cmpxchg.org>