The quilt patch titled Subject: mm: page_alloc: free pages to correct buddy list after PCP lock contention has been removed from the -mm tree. Its filename was mm-page_alloc-free-pages-to-correct-buddy-list-after-pcp-lock-contention.patch
This patch was dropped because an alternative patch was or shall be merged
------------------------------------------------------ From: Mel Gorman mgorman@techsingularity.net Subject: mm: page_alloc: free pages to correct buddy list after PCP lock contention Date: Tue, 5 Sep 2023 10:09:22 +0100
Commit 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock") returns pages to the buddy list on PCP lock contention. However, for migratetypes that are not MIGRATE_PCPTYPES, the migratetype may have been clobbered already for pages that are not being isolated. In practice, this means that CMA pages may be returned to the wrong buddy list. While this might be harmless in some cases as it is MIGRATE_MOVABLE, the pageblock could be reassigned in rmqueue_fallback and prevent a future CMA allocation. Lookup the PCP migratetype against unconditionally if the PCP lock is contended.
[lecopzer.chen@mediatek.com: CMA-specific fix] Link: https://lkml.kernel.org/r/20230905090922.zy7srh33rg5c3zao@techsingularity.ne... Fixes: 4b23a68f9536 ("mm/page_alloc: protect PCP lists with a spinlock") Signed-off-by: Mel Gorman mgorman@techsingularity.net Reported-by: Joe Liu joe.liu@mediatek.com Acked-by: Vlastimil Babka vbabka@suse.cz Cc: Johannes Weiner hannes@cmpxchg.org Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
mm/page_alloc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
--- a/mm/page_alloc.c~mm-page_alloc-free-pages-to-correct-buddy-list-after-pcp-lock-contention +++ a/mm/page_alloc.c @@ -2428,7 +2428,13 @@ void free_unref_page(struct page *page, free_unref_page_commit(zone, pcp, page, migratetype, order); pcp_spin_unlock(pcp); } else { - free_one_page(zone, page, pfn, order, migratetype, FPI_NONE); + /* + * The page migratetype may have been clobbered for types + * (type >= MIGRATE_PCPTYPES && !is_migrate_isolate) so + * must be rechecked. + */ + free_one_page(zone, page, pfn, order, + get_pcppage_migratetype(page), FPI_NONE); } pcp_trylock_finish(UP_flags); } _
Patches currently in -mm which might be from mgorman@techsingularity.net are