From: Marek Szyprowski <m.szyprowski@samsung.com>
Date: Thu, 29 Nov 2012 03:17:28 +0000 (+1100)
Subject: mm: cma: skip watermarks check for already isolated blocks in split_free_page()
X-Git-Tag: next-20121205~1^2~292
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=b59d530a1b8ce20969e116e40a9e30fe8e181999;p=karo-tx-linux.git

mm: cma: skip watermarks check for already isolated blocks in split_free_page()

Since commit 2139cbe627b8 ("cma: fix counting of isolated pages") free
pages in isolated pageblocks are not accounted to NR_FREE_PAGES counters,
so watermarks check is not required if one operates on a free page in
isolated pageblock.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index b1fdde5439c9..54a2224649db 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1394,10 +1394,12 @@ int capture_free_page(struct page *page, int alloc_order, int migratetype)
 	zone = page_zone(page);
 	order = page_order(page);
 
-	/* Obey watermarks as if the page was being allocated */
-	watermark = low_wmark_pages(zone) + (1 << order);
-	if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
-		return 0;
+	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE) {
+		/* Obey watermarks as if the page was being allocated */
+		watermark = low_wmark_pages(zone) + (1 << order);
+		if (!zone_watermark_ok(zone, 0, watermark, 0, 0))
+			return 0;
+	}
 
 	/* Remove page from free list */
 	list_del(&page->lru);