mm: do_migrate_range: exit loop if not_managed is true

If not_managed is true all pages will be putback to lru, so break the loop
earlier to skip other pages isolate.
Signed-off-by: NBob Liu <lliubbo@gmail.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NWu Fengguang <fengguang.wu@intel.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

mm/memory_hotplug.c

@@ -696,15 +696,17 @@ do_migrate_range(unsigned long start_pfn, unsigned long end_pfn)
 					    page_is_file_cache(page));
 
 		} else {
-			/* Becasue we don't have big zone->lock. we should
-			   check this again here. */
-			if (page_count(page))
-				not_managed++;
 #ifdef CONFIG_DEBUG_VM
 			printk(KERN_ALERT "removing pfn %lx from LRU failed\n",
 			       pfn);
 			dump_page(page);
 #endif
+			/* Becasue we don't have big zone->lock. we should
+			   check this again here. */
+			if (page_count(page)) {
+				not_managed++;
+				break;
+			}
 		}
 	}
 	ret = -EBUSY;