The patch titled
mm: compaction: page buddy can go away before reading page_order while isolating pages for migration
has been added to the -mm tree. Its filename is
mm-compaction-memory-compaction-core-fix-page-buddy-can-go-away-before-reading-page_order-while-isolating-pages-for-migration.patch
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------------------------------------------------------
Subject: mm: compaction: page buddy can go away before reading page_order while isolating pages for migration
From: Andrea Arcangeli <aarcange@xxxxxxxxxx>
zone->lock isn't held so the optimisation is unsafe. The page could be
allocated between when PageBuddy is checked and page-order is called. The
scanner will harmlessly walk the other free pages so let's just skip this
optimization.
[mel@xxxxxxxxx: Expanded the changelog]
Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/compaction.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)
diff -puN mm/compaction.c~mm-compaction-memory-compaction-core-fix-page-buddy-can-go-away-before-reading-page_order-while-isolating-pages-for-migration mm/compaction.c
--- a/mm/compaction.c~mm-compaction-memory-compaction-core-fix-page-buddy-can-go-away-before-reading-page_order-while-isolating-pages-for-migration
+++ a/mm/compaction.c
@@ -258,10 +258,8 @@ static unsigned long isolate_migratepage
/* Get the page and skip if free */
page = pfn_to_page(low_pfn);
- if (PageBuddy(page)) {
- low_pfn += (1 << page_order(page)) - 1;
+ if (PageBuddy(page))
continue;
- }
/* Try isolate the page */
if (__isolate_lru_page(page, ISOLATE_BOTH, 0) != 0)
_
Patches currently in -mm which might be from aarcange@xxxxxxxxxx are
origin.patch
define-madv_hugepage.patch
mincore-cleanups.patch
mincore-break-do_mincore-into-logical-pieces.patch
mincore-pass-ranges-as-startend-address-pairs.patch
mincore-do-nested-page-table-walks.patch
mm-migration-take-a-reference-to-the-anon_vma-before-migrating.patch
mm-migration-do-not-try-to-migrate-unmapped-anonymous-pages.patch
mm-share-the-anon_vma-ref-counts-between-ksm-and-page-migration.patch
mm-allow-config_migration-to-be-set-without-config_numa-or-memory-hot-remove.patch
mm-allow-config_migration-to-be-set-without-config_numa-or-memory-hot-remove-fix.patch
mm-export-unusable-free-space-index-via-proc-unusable_index.patch
mm-export-fragmentation-index-via-proc-extfrag_index.patch
mm-move-definition-for-lru-isolation-modes-to-a-header.patch
mm-compaction-memory-compaction-core.patch
mm-compaction-memory-compaction-core-fix.patch
mm-compaction-memory-compaction-core-fix-page-buddy-can-go-away-before-reading-page_order-while-isolating-pages-for-migration.patch
mm-compaction-add-proc-trigger-for-memory-compaction.patch
mm-compaction-add-proc-trigger-for-memory-compaction-fix.patch
mm-compaction-add-proc-trigger-for-memory-compaction-fix-fix.patch
mm-compaction-add-sys-trigger-for-per-node-memory-compaction.patch
mm-compaction-direct-compact-when-a-high-order-allocation-fails.patch
mm-compaction-direct-compact-when-a-high-order-allocation-fails-reject-fix.patch
mm-compaction-add-a-tunable-that-decides-when-memory-should-be-compacted-and-when-it-should-be-reclaimed.patch
mm-compaction-do-not-compact-within-a-preferred-zone-after-a-compaction-failure.patch
mm-migration-allow-the-migration-of-pageswapcache-pages.patch
mm-migration-allow-the-migration-of-pageswapcache-pages-fix.patch
mm-compaction-do-not-display-compaction-related-stats-when-config_compaction.patch
mm-compaction-do-not-display-compaction-related-stats-when-config_compaction-reject-fix.patch
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