The patch titled
Subject: mm: compaction: skip more fully scanned pageblock
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-skip-more-fully-scanned-pageblock.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-skip-more-fully-scanned-pageblock.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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------------------------------------------------------
From: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Subject: mm: compaction: skip more fully scanned pageblock
Date: Thu, 25 May 2023 20:53:58 +0800
In fast_isolate_around(), it assumes the pageblock is fully scanned if
cc->nr_freepages < cc->nr_migratepages after trying to isolate some free
pages, and will set skip flag to avoid scanning in future. However this
can miss setting the skip flag for a fully scanned pageblock (returned
'start_pfn' is equal to 'end_pfn') in the case where cc->nr_freepages is
larger than cc->nr_migratepages.
So using the returned 'start_pfn' from isolate_freepages_block() and
'end_pfn' to decide if a pageblock is fully scanned makes more sense. It
can also cover the case where cc->nr_freepages < cc->nr_migratepages,
which means the 'start_pfn' is usually equal to 'end_pfn' except some
uncommon fatal error occurs after non-strict mode isolation.
Link: https://lkml.kernel.org/r/f4efd2fa08735794a6d809da3249b6715ba6ad38.1685018752.git.baolin.wang@xxxxxxxxxxxxxxxxx
Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxxxxxxxxx>
Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/compaction.c~mm-compaction-skip-more-fully-scanned-pageblock
+++ a/mm/compaction.c
@@ -1419,7 +1419,7 @@ fast_isolate_around(struct compact_contr
isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
- if (cc->nr_freepages < cc->nr_migratepages)
+ if (start_pfn == end_pfn)
set_pageblock_skip(page);
return;
_
Patches currently in -mm which might be from baolin.wang@xxxxxxxxxxxxxxxxx are
mm-page_alloc-drop-the-unnecessary-pfn_valid-for-start-pfn.patch
mm-compaction-drop-the-redundant-page-validation-in-update_pageblock_skip.patch
mm-compaction-change-fast_isolate_freepages-to-void-type.patch
mm-compaction-skip-more-fully-scanned-pageblock.patch
mm-compaction-only-set-skip-flag-if-cc-no_set_skip_hint-is-false.patch
mm-compaction-add-trace-event-for-fast-freepages-isolation.patch
mm-compaction-skip-fast-freepages-isolation-if-enough-freepages-are-isolated.patch
