[PATCH] mm: skip the page buddy block instead of one page

From: Xishi Qiu <qiuxishi@huawei.com>
To: Andrew Morton <akpm@linux-foundation.org>,
	Mel Gorman <mgorman@suse.de>, <riel@redhat.com>,
	Minchan Kim <minchan@kernel.org>, <aquini@redhat.com>
Cc: <linux-mm@kvack.org>, LKML <linux-kernel@vger.kernel.org>,
	Xishi Qiu <qiuxishi@huawei.com>
Subject: [PATCH] mm: skip the page buddy block instead of one page
Date: Wed, 14 Aug 2013 12:45:41 +0800	[thread overview]
Message-ID: <520B0B75.4030708@huawei.com> (raw)

A large free page buddy block will continue many times, so if the page 
is free, skip the whole page buddy block instead of one page.

Signed-off-by: Xishi Qiu <qiuxishi@huawei.com>
---
 mm/compaction.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 05ccb4c..874bae1 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -520,9 +520,10 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 			goto next_pageblock;
 
 		/* Skip if free */
-		if (PageBuddy(page))
+		if (PageBuddy(page)) {
+			low_pfn += (1 << page_order(page)) - 1;
 			continue;
-
+		}
 		/*
 		 * For async migration, also only scan in MOVABLE blocks. Async
 		 * migration is optimistic to see if the minimum amount of work
-- 
1.7.1

