From: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Date: Fri, 28 Sep 2012 00:19:37 +0000 (+1000)
Subject: mm: fix tracing in free_pcppages_bulk()
X-Git-Tag: next-20121004~1^2~268
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=2efa7f999ddfc23b766cea0d4be55177787591c7;p=karo-tx-linux.git

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 a701623 ("mm: fix migratetype bug which
slowed swapping").  This caused incorrect data to be attached to the
mm_page_pcpu_drain trace event.

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>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 028617d1ca65..76aff40ae9c3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -667,12 +667,15 @@ static void free_pcppages_bulk(struct zone *zone, int count,
 			batch_free = to_free;
 
 		do {
+			int mt;
+
 			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);