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From:   Zi Yan <ziy@nvidia.com>
To:     Huang Ying <ying.huang@intel.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Yang Shi <yang.shi@linux.alibaba.com>,
        Yang Shi <shy828301@gmail.com>, Michal Hocko <mhocko@suse.com>,
        Wei Xu <weixugc@google.com>,
        Oscar Salvador <osalvador@suse.de>,
        David Rientjes <rientjes@google.com>,
        Dan Williams <dan.j.williams@intel.com>,
        David Hildenbrand <david@redhat.com>,
        Greg Thelen <gthelen@google.com>,
        Keith Busch <kbusch@kernel.org>
Subject: Re: [PATCH -V11 8/9] mm/vmscan: never demote for memcg reclaim
Date:   Wed, 21 Jul 2021 17:38:45 -0400
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In-Reply-To: <20210721063926.3024591-8-ying.huang@intel.com>
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On 21 Jul 2021, at 2:39, Huang Ying wrote:

> From: Dave Hansen <dave.hansen@linux.intel.com>
>
> Global reclaim aims to reduce the amount of memory used on a given node=
 or
> set of nodes.  Migrating pages to another node serves this purpose.
>
> memcg reclaim is different.  Its goal is to reduce the total memory
> consumption of the entire memcg, across all nodes.  Migration does not
> assist memcg reclaim because it just moves page contents between nodes
> rather than actually reducing memory consumption.
>
> Link: https://lkml.kernel.org/r/20210715055145.195411-9-ying.huang@inte=
l.com
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Suggested-by: Yang Shi <yang.shi@linux.alibaba.com>
> Reviewed-by: Yang Shi <shy828301@gmail.com>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Wei Xu <weixugc@google.com>
> Cc: Oscar Salvador <osalvador@suse.de>
> Cc: Zi Yan <ziy@nvidia.com>
> Cc: David Rientjes <rientjes@google.com>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Greg Thelen <gthelen@google.com>
> Cc: Keith Busch <kbusch@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> ---
>  mm/vmscan.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)

LGTM. Reviewed-by: Zi Yan <ziy@nvidia.com>.

Should this be folded into Patch 4 when can_demote() is introduced?


=E2=80=94
Best Regards,
Yan, Zi

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