[RFC]handle error of rmqueue_bulk

[Shaohua Li <shaohua.li@intel.com>]

if rmqueue_bulk fails, we might get page with wrong migratetype,
shouldn't we consider the case? 

Thanks,
Shaohua

Index: linux/mm/page_alloc.c
===================================================================
--- linux.orig/mm/page_alloc.c	2007-12-14 16:44:35.000000000 +0800
+++ linux/mm/page_alloc.c	2007-12-14 16:45:42.000000000 +0800
@@ -1067,8 +1067,12 @@ again:
 
 		/* Allocate more to the pcp list if necessary */
 		if (unlikely(&page->lru == &pcp->list)) {
-			pcp->count += rmqueue_bulk(zone, 0,
+			int cn;
+			cn = rmqueue_bulk(zone, 0,
 					pcp->batch, &pcp->list, migratetype);
+			if (unlikely(!cn))
+				goto failed;
+			pcp->count += cn;
 			page = list_entry(pcp->list.next, struct page, lru);
 		}