From 770c8aaaf6f04a87e6765f24d497132de9152a46 Mon Sep 17 00:00:00 2001 From: Bartlomiej Zolnierkiewicz Date: Mon, 8 Oct 2012 16:31:57 -0700 Subject: [PATCH] mm: fix tracing in free_pcppages_bulk() page->private gets re-used in __free_one_page() to store page order (so trace_mm_page_pcpu_drain() may print order instead of migratetype) thus migratetype value must be cached locally. Fixes regression introduced in commit a7016235a61d ("mm: fix migratetype bug which slowed swapping"). This caused incorrect data to be attached to the mm_page_pcpu_drain trace event. [akpm@linux-foundation.org: add comment] Cc: Marek Szyprowski Cc: Michal Nazarewicz Acked-by: Minchan Kim Acked-by: Mel Gorman Cc: Hugh Dickins Signed-off-by: Bartlomiej Zolnierkiewicz Signed-off-by: Kyungmin Park Acked-by: KOSAKI Motohiro Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index cefd14e6dcf2..3f18a14effb8 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -668,12 +668,15 @@ static void free_pcppages_bulk(struct zone *zone, int count, batch_free = to_free; do { + int mt; /* migratetype of the to-be-freed page */ + page = list_entry(list->prev, struct page, lru); /* must delete as __free_one_page list manipulates */ list_del(&page->lru); + mt = page_private(page); /* MIGRATE_MOVABLE list may include MIGRATE_RESERVEs */ - __free_one_page(page, zone, 0, page_private(page)); - trace_mm_page_pcpu_drain(page, 0, page_private(page)); + __free_one_page(page, zone, 0, mt); + trace_mm_page_pcpu_drain(page, 0, mt); } while (--to_free && --batch_free && !list_empty(list)); } __mod_zone_page_state(zone, NR_FREE_PAGES, count);