linux-kernel - Re: [PATCH v2] mm: memcontrol: fix possible memcg leak due to interrupted reclaim

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Message-ID: <20151223221906.GB12165@cmpxchg.org>
Date:	Wed, 23 Dec 2015 17:19:06 -0500
From:	Johannes Weiner <hannes@...xchg.org>
To:	Vladimir Davydov <vdavydov@...tuozzo.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>, stable@...r.kernel.org,
	Michal Hocko <mhocko@...nel.org>, linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mm: memcontrol: fix possible memcg leak due to
 interrupted reclaim

I think we can fold the following in there as well:

>From b885bf06f55d05f0e8249357d4edb231dfe4a5dc Mon Sep 17 00:00:00 2001
From: Johannes Weiner <hannes@...xchg.org>
Date: Wed, 23 Dec 2015 17:16:07 -0500
Subject: [PATCH] mm: memcontrol: fix possible memcg leak due to interrupted
 reclaim fix

When we handled multiple css references in mem_cgroup_iter() it got a
little confusing which puts belong to which gets. Now that we only ref
the position css it's obvious, and a multi-line comment to explain it
gets in the way of reading an already long function.

Signed-off-by: Johannes Weiner <hannes@...xchg.org>
---
 mm/memcontrol.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 99acd6a..498c61e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -909,10 +909,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root,
 		 */
 		(void)cmpxchg(&iter->position, pos, memcg);
 
-		/*
-		 * pairs with css_tryget when dereferencing iter->position
-		 * above.
-		 */
 		if (pos)
 			css_put(&pos->css);
 
-- 
2.6.4
--
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