linux-kernel - [patch 7/7] mm: memcg: remove unneeded checks from uncharge

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Date:	Tue, 29 Nov 2011 11:52:05 +0100
From:	Johannes Weiner <hannes@...xchg.org>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Michal Hocko <mhocko@...e.cz>,
	Balbir Singh <bsingharora@...il.com>,
	David Rientjes <rientjes@...gle.com>,
	Hugh Dickins <hughd@...gle.com>, cgroups@...r.kernel.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org
Subject: [patch 7/7] mm: memcg: remove unneeded checks from uncharge_page()

From: Johannes Weiner <jweiner@...hat.com>

mem_cgroup_uncharge_page() is only called on either freshly allocated
pages without page->mapping or on rmapped PageAnon() pages.  There is
no need to check for a page->mapping that is not an anon_vma.

Signed-off-by: Johannes Weiner <jweiner@...hat.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>
Acked-by: Michal Hocko <mhocko@...e.cz>
---
 mm/memcontrol.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f5aa1b8..468a5a4 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2992,8 +2992,7 @@ void mem_cgroup_uncharge_page(struct page *page)
 	/* early check. */
 	if (page_mapped(page))
 		return;
-	if (page->mapping && !PageAnon(page))
-		return;
+	VM_BUG_ON(page->mapping && !PageAnon(page));
 	__mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
 }
 
-- 
1.7.6.4

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