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References: <20201211041954.79543-1-songmuchun@bytedance.com> <20201211041954.79543-2-songmuchun@bytedance.com>
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From:   Pankaj Gupta <pankaj.gupta.linux@gmail.com>
Date:   Fri, 11 Dec 2020 08:33:34 +0100
Message-ID: <CAM9Jb+gc-xqPNP0jsuRV5xczBh31rM=cgL46SxxAYSohe8RvwQ@mail.gmail.com>
Subject: Re: [PATCH v4 1/7] mm: memcontrol: fix NR_ANON_THPS accounting in
 charge moving
To:     Muchun Song <songmuchun@bytedance.com>
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "Rafael J. Wysocki" <rafael@kernel.org>, adobriyan@gmail.com,
        Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>, vdavydov.dev@gmail.com,
        Hugh Dickins <hughd@google.com>,
        Shakeel Butt <shakeelb@google.com>, guro@fb.com,
        Sami Tolvanen <samitolvanen@google.com>, feng.tang@intel.com,
        neilb@suse.de, Joonsoo Kim <iamjoonsoo.kim@lge.com>,
        Randy Dunlap <rdunlap@infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-fsdevel@vger.kernel.org, Linux MM <linux-mm@kvack.org>,
        cgroups@vger.kernel.org, Michal Hocko <mhocko@suse.com>
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> The unit of NR_ANON_THPS is HPAGE_PMD_NR already. So it should inc/dec
> by one rather than nr_pages.
>
> Fixes: 468c398233da ("mm: memcontrol: switch to native NR_ANON_THPS counter")
> Signed-off-by: Muchun Song <songmuchun@bytedance.com>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Reviewed-by: Roman Gushchin <guro@fb.com>
> ---
>  mm/memcontrol.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index b80328f52fb4..8818bf64d6fe 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5653,10 +5653,8 @@ static int mem_cgroup_move_account(struct page *page,
>                         __mod_lruvec_state(from_vec, NR_ANON_MAPPED, -nr_pages);
>                         __mod_lruvec_state(to_vec, NR_ANON_MAPPED, nr_pages);
>                         if (PageTransHuge(page)) {
> -                               __mod_lruvec_state(from_vec, NR_ANON_THPS,
> -                                                  -nr_pages);
> -                               __mod_lruvec_state(to_vec, NR_ANON_THPS,
> -                                                  nr_pages);
> +                               __dec_lruvec_state(from_vec, NR_ANON_THPS);
> +                               __inc_lruvec_state(to_vec, NR_ANON_THPS);
>                         }
>
>                 }

Acked-by: Pankaj Gupta <pankaj.gupta@cloud.ionos.com>