From: Shaohua Li <shaohua.li@intel.com>
Date: Tue, 22 Sep 2009 00:01:18 +0000 (-0700)
Subject: memory hotplug: make pages from movable zone always isolatable
X-Git-Tag: v2.6.32-rc1~592
X-Git-Url: http://bbs.cooldavid.org/git/?a=commitdiff_plain;h=8e7e40d9658cf7b2ae2b76484e235799b3ddaa97;p=net-next-2.6.git

memory hotplug: make pages from movable zone always isolatable

Pages on movable zone have two types, MIGRATE_MOVABLE and MIGRATE_RESERVE,
both them can be movable, because only movable memory allocation can get
pages from movable zone.  This makes pages in movable zone always be able
to migrate.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Yakui Zhao <yakui.zhao@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 8a830271172..7b4d4e4ea64 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -4906,13 +4906,16 @@ int set_migratetype_isolate(struct page *page)
 	struct zone *zone;
 	unsigned long flags;
 	int ret = -EBUSY;
+	int zone_idx;
 
 	zone = page_zone(page);
+	zone_idx = zone_idx(zone);
 	spin_lock_irqsave(&zone->lock, flags);
 	/*
 	 * In future, more migrate types will be able to be isolation target.
 	 */
-	if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE)
+	if (get_pageblock_migratetype(page) != MIGRATE_MOVABLE &&
+	    zone_idx != ZONE_MOVABLE)
 		goto out;
 	set_pageblock_migratetype(page, MIGRATE_ISOLATE);
 	move_freepages_block(zone, page, MIGRATE_ISOLATE);