Re: [RFC PATCH 0/4] Fix excessive CPU usage during compaction

[Vlastimil Babka]

On 1/26/23 02:11, Andrew Morton wrote:
> On Wed, 25 Jan 2023 13:44:30 +0000 Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> 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.