The quilt patch titled
Subject: mm/compaction: correct last_migrated_pfn update in compact_zone
has been removed from the -mm tree. Its filename was
mm-compaction-correct-last_migrated_pfn-update-in-compact_zone.patch
This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
------------------------------------------------------
From: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Subject: mm/compaction: correct last_migrated_pfn update in compact_zone
Date: Fri, 4 Aug 2023 19:04:48 +0800
We record start pfn of last isolated page block with last_migrated_pfn. And
then:
1. We check if we mark the page block skip for exclusive access in
isolate_migratepages_block by test if next migrate pfn is still in last
isolated page block. If so, we will set finish_pageblock to do the
rescan.
2. We check if a full cc->order block is scanned by test if last scan
range passes the cc->order block boundary. If so, we flush the pages
were freed.
We treat cc->migrate_pfn before isolate_migratepages as the start pfn of
last isolated page range. However, we always align migrate_pfn to page
block or move to another page block in fast_find_migrateblock or in
linearly scan forward in isolate_migratepages before do page isolation in
isolate_migratepages_block.
Update last_migrated_pfn with pageblock_start_pfn(cc->migrate_pfn - 1)
after scan to correctly set start pfn of last isolated page range. To
avoid that:
1. Miss a rescan with finish_pageblock set as last_migrate_pfn does
not point to right pageblock and the migrate will not be in pageblock
of last_migrate_pfn as it should be.
2. Wrongly issue flush by test cc->order block boundary with wrong
last_migrate_pfn.
Link: https://lkml.kernel.org/r/20230804110454.2935878-3-shikemeng@xxxxxxxxxxxxxxx
Signed-off-by: Kemeng Shi <shikemeng@xxxxxxxxxxxxxxx>
Reviewed-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/mm/compaction.c~mm-compaction-correct-last_migrated_pfn-update-in-compact_zone
+++ a/mm/compaction.c
@@ -2507,7 +2507,8 @@ rescan:
goto check_drain;
case ISOLATE_SUCCESS:
update_cached = false;
- last_migrated_pfn = iteration_start_pfn;
+ last_migrated_pfn = max(cc->zone->zone_start_pfn,
+ pageblock_start_pfn(cc->migrate_pfn - 1));
}
err = migrate_pages(&cc->migratepages, compaction_alloc,
_
Patches currently in -mm which might be from shikemeng@xxxxxxxxxxxxxxx are
