The patch titled
Subject: mm: compaction: update pageblock skip when first migration candidate is not at the start
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-update-pageblock-skip-when-first-migration-candidate-is-not-at-the-start.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-update-pageblock-skip-when-first-migration-candidate-is-not-at-the-start.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: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Subject: mm: compaction: update pageblock skip when first migration candidate is not at the start
Date: Mon, 15 May 2023 12:33:43 +0100
isolate_migratepages_block should mark a pageblock as skip if scanning
started on an aligned pageblock boundary but it only updates the skip flag
if the first migration candidate is also aligned. Tracing during a
compaction stress load (mmtests: workload-usemem-stress-numa-compact) that
many pageblocks are not marked skip causing excessive scanning of blocks
that had been recently checked. Update pageblock skip based on
"valid_page" which is set if scanning started on a pageblock boundary.
Link: https://lkml.kernel.org/r/20230515113344.6869-4-mgorman@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx>
Cc: Chuyi Zhou <zhouchuyi@xxxxxxxxxxxxx>
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>
---
mm/compaction.c | 15 +++++----------
1 file changed, 5 insertions(+), 10 deletions(-)
--- a/mm/compaction.c~mm-compaction-update-pageblock-skip-when-first-migration-candidate-is-not-at-the-start
+++ a/mm/compaction.c
@@ -392,18 +392,14 @@ void reset_isolation_suitable(pg_data_t
* Sets the pageblock skip bit if it was clear. Note that this is a hint as
* locks are not required for read/writers. Returns true if it was already set.
*/
-static bool test_and_set_skip(struct compact_control *cc, struct page *page,
- unsigned long pfn)
+static bool test_and_set_skip(struct compact_control *cc, struct page *page)
{
bool skip;
- /* Do no update if skip hint is being ignored */
+ /* Do not update if skip hint is being ignored */
if (cc->ignore_skip_hint)
return false;
- if (!pageblock_aligned(pfn))
- return false;
-
skip = get_pageblock_skip(page);
if (!skip && !cc->no_set_skip_hint)
set_pageblock_skip(page);
@@ -470,8 +466,7 @@ static void update_cached_migrate(struct
{
}
-static bool test_and_set_skip(struct compact_control *cc, struct page *page,
- unsigned long pfn)
+static bool test_and_set_skip(struct compact_control *cc, struct page *page)
{
return false;
}
@@ -1103,9 +1098,9 @@ isolate_migratepages_block(struct compac
lruvec_memcg_debug(lruvec, page_folio(page));
/* Try get exclusive access under lock */
- if (!skip_updated) {
+ if (!skip_updated && valid_page) {
skip_updated = true;
- if (test_and_set_skip(cc, page, low_pfn))
+ if (test_and_set_skip(cc, valid_page))
goto isolate_abort;
}
_
Patches currently in -mm which might be from mgorman@xxxxxxxxxxxxxxxxxxx are
mm-compaction-ensure-rescanning-only-happens-on-partially-scanned-pageblocks.patch
mm-compaction-only-force-pageblock-scan-completion-when-skip-hints-are-obeyed.patch
mm-compaction-update-pageblock-skip-when-first-migration-candidate-is-not-at-the-start.patch
revert-revert-mm-compaction-fix-set-skip-in-fast_find_migrateblock.patch
