Commit 770c8aaa authored Oct 08, 2012 by Bartlomiej Zolnierkiewicz Committed by Linus Torvalds Oct 09, 2012

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 a7016235 ("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 <m.szyprowski@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 02c6de8d

mm/page_alloc.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -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);

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