The patch titled
Date: Wed Jul 13 14:20:09 2022 +0800
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
Frm: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
Date: Wed Jul 13 14:20:09 2022 +0800
Subject: mm/compaction: fix set skip in fast_find_migrateblock
(akpm: this is a reapplication of 7efc3b726103, after Mel's "Fix excessive
CPU usage during compaction" series addressed issues whcih this patch
originally exposed).
When we successfully find a pageblock in fast_find_migrateblock(), the
block will be set skip-flag through set_pageblock_skip(). However, when
entering isolate_migratepages_block(), the whole pageblock will be skipped
due to the branch 'if (!valid_page && IS_ALIGNED(low_pfn,
pageblock_nr_pages))'. Eventually we will goto isolate_abort and isolate
nothing. That makes fast_find_migrateblock useless.
In this patch, when we find a suitable pageblock in
fast_find_migrateblock, we do noting but let isolate_migratepages_block to
set skip flag to the pageblock after scan it. Normally, we would isolate
some pages from the fast-find block.
I use mmtest/thpscale-madvhugepage test it. Here is the result:
baseline patch
Amean fault-both-1 1331.66 ( 0.00%) 1261.04 * 5.30%*
Amean fault-both-3 1383.95 ( 0.00%) 1191.69 * 13.89%*
Amean fault-both-5 1568.13 ( 0.00%) 1445.20 * 7.84%*
Amean fault-both-7 1819.62 ( 0.00%) 1555.13 * 14.54%*
Amean fault-both-12 1106.96 ( 0.00%) 1149.43 * -3.84%*
Amean fault-both-18 2196.93 ( 0.00%) 1875.77 * 14.62%*
Amean fault-both-24 2642.69 ( 0.00%) 2671.21 * -1.08%*
Amean fault-both-30 2901.89 ( 0.00%) 2857.32 * 1.54%*
Amean fault-both-32 3747.00 ( 0.00%) 3479.23 * 7.15%*
Link: https://lkml.kernel.org/r/20220713062009.597255-1-zhouchuyi@xxxxxxxxxxxxx
Fixes: 70b44595eafe9 ("mm, compaction: use free lists to quickly locate a migration source")
Signed-off-by: zhouchuyi <zhouchuyi@xxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Cc: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Pedro Falcato <pedro.falcato@xxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
--- a/mm/compaction.c~mm-compaction-fix-set-skip-in-fast_find_migrateblock
+++ a/mm/compaction.c
@@ -1845,7 +1845,6 @@ static unsigned long fast_find_migratebl
pfn = cc->zone->zone_start_pfn;
cc->fast_search_fail = 0;
found_block = true;
- set_pageblock_skip(freepage);
break;
}
}
_
Patches currently in -mm which might be from zhouchuyi@xxxxxxxxxxxxx are
