Message-ID: <7ad2cbdc-8589-3aa2-b16a-41336f849f65@suse.cz>
Date:   Sun, 29 Jan 2023 19:03:54 +0100
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Subject: Re: [RFC PATCH 0/4] Fix excessive CPU usage during compaction
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To:     Andrew Morton <akpm@linux-foundation.org>,
        Mel Gorman <mgorman@techsingularity.net>
Cc:     Jiri Slaby <jirislaby@kernel.org>,
        Maxim Levitsky <mlevitsk@redhat.com>,
        Michal Hocko <mhocko@kernel.org>,
        Pedro Falcato <pedro.falcato@gmail.com>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Chuyi Zhou <zhouchuyi@bytedance.com>,
        Linux-MM <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <20230125134434.18017-1-mgorman@techsingularity.net>
 <20230125171159.355a770a2e34f78d7664e1f0@linux-foundation.org>
From:   Vlastimil Babka <vbabka@suse.cz>
In-Reply-To: <20230125171159.355a770a2e34f78d7664e1f0@linux-foundation.org>
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On 1/26/23 02:11, Andrew Morton wrote:
> On Wed, 25 Jan 2023 13:44:30 +0000 Mel Gorman <mgorman@techsingularity.net> wrote:
> 
> If we drop Vlastimil's reversion and apply this, the whole series
> should be cc:stable and it isn't really designed for that.
> 
> So I think either
> 
> a) drop Vlastimil's reversion and persuade Mel to send us a minimal
>    version of patch #4 for -stable consumption.  Patches 1-3 of this
>    series come later.
> 
> b) go ahead with Vlastimil's revert for -stable, queue up this
>    series for 6.3-rc1 and redo the original "fix set skip in
>    fast_find_migrateblock" some time in the future.
> 
> If we go with b) then the Fixes: tag in "[PATCH 4/4] mm, compaction:
> Finish pageblocks on complete migration failure" is inappropriate -
> fixing a reverted commit which Vlastimil's revert already fixed.
> 
> I'll plan on b) for now.

Agreed with the plan b). I couldn't review this yet due to being sick,
but I doubt I would have enough confidence to fast-track the series to
6.2 and 6.1-stable. It's subtle enough area and extra time in -next and
full -rc cycle will help.