From: Michal Hocko <mhocko@suse.cz>
Date: Wed, 23 Mar 2011 23:42:41 +0000 (-0700)
Subject: memcg: page_cgroup array is never stored on reserved pages
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=6cfddb261555dd0c0529a5fb7cf8bc5b85ad95a5;p=linux-beck.git

memcg: page_cgroup array is never stored on reserved pages

KAMEZAWA Hiroyuki noted that free_pages_cgroup doesn't have to check for
PageReserved because we never store the array on reserved pages (neither
alloc_pages_exact nor vmalloc use those pages).

So we can replace the check by a BUG_ON.

Signed-off-by: Michal Hocko <mhocko@suse.cz>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

diff --git a/mm/page_cgroup.c b/mm/page_cgroup.c
index 8e7577cdf5e4..a12cc3fa9859 100644
--- a/mm/page_cgroup.c
+++ b/mm/page_cgroup.c
@@ -153,11 +153,11 @@ static void free_page_cgroup(void *addr)
 		vfree(addr);
 	} else {
 		struct page *page = virt_to_page(addr);
-		if (!PageReserved(page)) { /* Is bootmem ? */
-			size_t table_size =
-				sizeof(struct page_cgroup) * PAGES_PER_SECTION;
-			free_pages_exact(addr, table_size);
-		}
+		size_t table_size =
+			sizeof(struct page_cgroup) * PAGES_PER_SECTION;
+
+		BUG_ON(PageReserved(page));
+		free_pages_exact(addr, table_size);
 	}
 }
 #endif