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References: <20210809223740.59009-1-npache@redhat.com> <YRKa0yzEDALtvSZO@cmpxchg.org>
 <a7afc485-9036-8f09-e582-f2eb45620670@redhat.com>
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From:   Shakeel Butt <shakeelb@google.com>
Date:   Tue, 10 Aug 2021 14:17:50 -0700
Message-ID: <CALvZod5L+cyON5qRX3eSdHbo+-H7VDQeFuYYNqpK5diCcv9OMw@mail.gmail.com>
Subject: Re: [PATCH v3] vm_swappiness=0 should still try to avoid swapping
 anon memory
To:     Nico Pache <npache@redhat.com>
Cc:     Johannes Weiner <hannes@cmpxchg.org>,
        Linux MM <linux-mm@kvack.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Rafael Aquini <aquini@redhat.com>,
        Waiman Long <llong@redhat.com>, Michal Hocko <mhocko@suse.com>,
        hakavlad@inbox.lv
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On Tue, Aug 10, 2021 at 12:24 PM Nico Pache <npache@redhat.com> wrote:
>
>
[...]
> >
> > I'm wondering how you're getting anon scans with swappiness=0. If you
> > look at get_scan_count(), SCAN_FRACT with swappines=0 should always
> > result in ap = fraction[0] = 0, which never yields any anon scan
> > targets. So I'm thinking you're running into sc->file_is_tiny
> > situations, meaning remaining file pages alone are not enough to
> > restore watermarks anymore. Is that possible?
>
> Yes DEACTIVATE_ANON is enabling the file_is_tiny case in shrink_node(). That is what im trying to prevent in the swappiness=0 case.
>

Can you please explain how DEACTIVATE_ANON is enabling the file_is_tiny case?