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References: <20210413065153.63431-1-songmuchun@bytedance.com> <20210413065153.63431-5-songmuchun@bytedance.com>
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From:   Shakeel Butt <shakeelb@google.com>
Date:   Tue, 13 Apr 2021 06:28:09 -0700
Message-ID: <CALvZod6P4O8JicK22=RfjLk205kTDNDV=WonO0yXE0Fx7ydsGg@mail.gmail.com>
Subject: Re: [PATCH 4/7] mm: memcontrol: simplify lruvec_holds_page_lru_lock
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
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On Mon, Apr 12, 2021 at 11:57 PM Muchun Song <songmuchun@bytedance.com> wrote:
>
> We already have a helper lruvec_memcg() to get the memcg from lruvec, we
> do not need to do it ourselves in the lruvec_holds_page_lru_lock(). So use
> lruvec_memcg() instead. And if mem_cgroup_disabled() returns false, the
> page_memcg(page) (the LRU pages) cannot be NULL. So remove the odd logic
> of "memcg = page_memcg(page) ? : root_mem_cgroup". And use lruvec_pgdat
> to simplify the code. We can have a single definition for this function
> that works for !CONFIG_MEMCG, CONFIG_MEMCG + mem_cgroup_disabled() and
> CONFIG_MEMCG.
>
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

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