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From:   Muchun Song <songmuchun@bytedance.com>
Date:   Sat, 10 Jul 2021 18:54:20 +0800
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Subject: Re: [External] [PATCH v3 1/3] mm, memcg: add mem_cgroup_disabled
 checks in vmpressure and swap-related functions
To:     Suren Baghdasaryan <surenb@google.com>
Cc:     Tejun Heo <tj@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Vladimir Davydov <vdavydov.dev@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Shakeel Butt <shakeelb@google.com>,
        Roman Gushchin <guro@fb.com>, Yang Shi <shy828301@gmail.com>,
        Alex Shi <alexs@kernel.org>,
        Wei Yang <richard.weiyang@gmail.com>,
        Vlastimil Babka <vbabka@suse.cz>, Jens Axboe <axboe@kernel.dk>,
        Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        David Hildenbrand <david@redhat.com>,
        Matthew Wilcox <willy@infradead.org>, apopple@nvidia.com,
        Minchan Kim <minchan@kernel.org>,
        Miaohe Lin <linmiaohe@huawei.com>,
        LKML <linux-kernel@vger.kernel.org>,
        Cgroups <cgroups@vger.kernel.org>,
        Linux Memory Management List <linux-mm@kvack.org>,
        kernel-team@android.com
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On Sat, Jul 10, 2021 at 8:36 AM Suren Baghdasaryan <surenb@google.com> wrote:
>
> Add mem_cgroup_disabled check in vmpressure, mem_cgroup_uncharge_swap and
> cgroup_throttle_swaprate functions. This minimizes the memcg overhead in
> the pagefault and exit_mmap paths when memcgs are disabled using
> cgroup_disable=memory command-line option.
> This change results in ~2.1% overhead reduction when running PFT test
> comparing {CONFIG_MEMCG=n, CONFIG_MEMCG_SWAP=n} against {CONFIG_MEMCG=y,
> CONFIG_MEMCG_SWAP=y, cgroup_disable=memory} configuration on an 8-core
> ARM64 Android device.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Shakeel Butt <shakeelb@google.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>

The changes are straightforward. LGTM.
Reviewed-by: Muchun Song <songmuchun@bytedance.com>