[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-Id: <1414074830-14623-1-git-send-email-hannes@cmpxchg.org>
Date: Thu, 23 Oct 2014 10:33:50 -0400
From: Johannes Weiner <hannes@...xchg.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Vladimir Davydov <vdavydov@...allels.com>,
Michal Hocko <mhocko@...e.cz>, linux-mm@...ck.org,
cgroups@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [patch] mm: memcontrol: don't pass a NULL memcg to mem_cgroup_end_move()
mem_cgroup_end_move() checks if the passed memcg is NULL, along with a
lengthy comment to explain why this seemingly non-sensical situation
is even possible.
Check in cancel_attach() itself whether can_attach() set up the move
context or not, it's a lot more obvious from there. Then remove the
check and comment in mem_cgroup_end_move().
Signed-off-by: Johannes Weiner <hannes@...xchg.org>
Acked-by: Vladimir Davydov <vdavydov@...allels.com>
---
mm/memcontrol.c | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a5c9aa4688e8..3cd4f1e0bfb3 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1469,12 +1469,7 @@ static void mem_cgroup_start_move(struct mem_cgroup *memcg)
static void mem_cgroup_end_move(struct mem_cgroup *memcg)
{
- /*
- * Now, mem_cgroup_clear_mc() may call this function with NULL.
- * We check NULL in callee rather than caller.
- */
- if (memcg)
- atomic_dec(&memcg->moving_account);
+ atomic_dec(&memcg->moving_account);
}
/*
@@ -5489,7 +5484,8 @@ static int mem_cgroup_can_attach(struct cgroup_subsys_state *css,
static void mem_cgroup_cancel_attach(struct cgroup_subsys_state *css,
struct cgroup_taskset *tset)
{
- mem_cgroup_clear_mc();
+ if (mc.to)
+ mem_cgroup_clear_mc();
}
static int mem_cgroup_move_charge_pte_range(pmd_t *pmd,
--
2.1.2
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists