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References: <20210409122959.82264-1-songmuchun@bytedance.com> <20210409122959.82264-2-songmuchun@bytedance.com>
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From:   Shakeel Butt <shakeelb@google.com>
Date:   Sat, 10 Apr 2021 10:44:30 -0700
Message-ID: <CALvZod7kYwt7XfuC6LnZreswKrXRLnUEZ7LbSSuNtgb-rdo=RA@mail.gmail.com>
Subject: Re: [RFC PATCH v2 01/18] mm: memcontrol: fix page charging in page replacement
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Roman Gushchin <guro@fb.com>, Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        Xiongchun duan <duanxiongchun@bytedance.com>,
        fam.zheng@bytedance.com, Balbir Singh <bsingharora@gmail.com>,
        Yang Shi <shy828301@gmail.com>,
        Alex Shi <alex.shi@linux.alibaba.com>
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On Fri, Apr 9, 2021 at 5:32 AM Muchun Song <songmuchun@bytedance.com> wrote:
>
> The pages aren't accounted at the root level, so do not charge the page
> to the root memcg in page replacement. Although we do not display the
> value (mem_cgroup_usage) so there shouldn't be any actual problem, but
> there is a WARN_ON_ONCE in the page_counter_cancel(). Who knows if it
> will trigger? So it is better to fix it.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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