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From:   Ivan Babrou <ivan@cloudflare.com>
Date:   Tue, 18 Feb 2020 14:07:11 -0800
Message-ID: <CABWYdi2sZGEEY-T=qyFOrtEGqo6+_Do+bfUJDSAcGhdJv1h0Ow@mail.gmail.com>
Subject: Re: Reclaim regression after 1c30844d2dfe
To:     Mel Gorman <mgorman@techsingularity.net>
Cc:     linux-mm@kvack.org, linux-kernel <linux-kernel@vger.kernel.org>,
        kernel-team <kernel-team@cloudflare.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Rik van Riel <riel@surriel.com>,
        Vlastimil Babka <vbabka@suse.cz>
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I won't have time to try the patch for the next three weeks or so, sorry.

On Wed, Feb 12, 2020 at 3:55 PM Mel Gorman <mgorman@techsingularity.net> wrote:
>
> On Wed, Feb 12, 2020 at 02:45:39PM -0800, Ivan Babrou wrote:
> > Here's a typical graph: https://imgur.com/a/n03x5yH
> >
> > * Green (numa0) and blue (numa1) for 4.19
> > * Yellow (numa0) and orange (numa1) for 5.4
> >
> > These downward slopes on numa0 on 5.4 are somewhat typical to the
> > worst case scenario.
> >
> > If I try to clean up data a bit from a bunch of machines, this is how
> > numa0 compares to numa1 with 1h average values of free memory above
> > 5GiB:
> >
> > * https://imgur.com/a/6T4rRzi
> >
> > I think it's safe to say that numa0 is much much worse, but I cannot
> > be 100% sure that numa1 is free from adverse effects, they may be just
> > hiding in the noise caused by rolling reboots.
> >
>
> Ok, while I expected node 0 to be worse in general, a runaway boost due
> to constant fragmentation would be a problem in general. In either case,
> the patch should reduce the damage. Is there any chance that the patch
> can be tested or would it be disruptive for you?
>
> --
> Mel Gorman
> SUSE Labs