mm/compaction: fix 'limit' in fast_isolate_freepages
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
Link: https://lkml.kernel.org/r/20210626082443.22547-1-vvghjk1234@gmail.com
Fixes: 0f880cf3eadd5 ("mm, compaction: use free lists to quickly locate a migration target")
Signed-off-by: Wonhyuk Yang <vvghjk1234@gmail.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
projects / kernel.git / commit