On Sat, Jun 26, 2021 at 05:24:43PM +0900, Wonhyuk Yang wrote:
> Because of 'min(1, ...)', fast_isolate_freepages set 'limit'
> to 0 or 1. This takes away the opportunities of find candinate
> pages. So, by making enough scans available, increases the
> probability of finding the appropriate freepage.
>
> Tested it on the thpscale and the results are as follows.
>
> 5.12.0 5.12.0
> valnilla patched
> Amean fault-both-1 598.15 ( 0.00%) 592.56 ( 0.93%)
> Amean fault-both-3 1494.47 ( 0.00%) 1514.35 ( -1.33%)
> Amean fault-both-5 2519.48 ( 0.00%) 2471.76 ( 1.89%)
> Amean fault-both-7 3173.85 ( 0.00%) 3079.19 ( 2.98%)
> Amean fault-both-12 8063.83 ( 0.00%) 7858.29 ( 2.55%)
> Amean fault-both-18 8781.20 ( 0.00%) 7827.70 * 10.86%*
> Amean fault-both-24 12576.44 ( 0.00%) 12250.20 ( 2.59%)
> Amean fault-both-30 18503.27 ( 0.00%) 17528.11 * 5.27%*
> Amean fault-both-32 16133.69 ( 0.00%) 13874.24 * 14.00%*
>
> 5.12.0 5.12.0
> vanilla patched
> Ops Compaction migrate scanned 6547133.00 5963901.00
> Ops Compaction free scanned 32452453.00 26609101.00
>
> 5.12 5.12
> vanilla patched
> Duration User 27.99 28.84
> Duration System 244.08 236.76
> Duration Elapsed 78.27 78.38
>
> Fixes: 5a811889de10f ("mm, compaction: use free lists to quickly locate a migration target")
> Signed-off-by: Wonhyuk Yang <vvghjk1234@xxxxxxxxx>
Acked-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
--
Mel Gorman
SUSE Labs
