From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934056AbaD3U2E (ORCPT ); Wed, 30 Apr 2014 16:28:04 -0400 Received: from zene.cmpxchg.org ([85.214.230.12]:59955 "EHLO zene.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759553AbaD3U0A (ORCPT ); Wed, 30 Apr 2014 16:26:00 -0400 From: Johannes Weiner To: linux-mm@kvack.org Cc: Michal Hocko , Hugh Dickins , Tejun Heo , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [patch 4/9] mm: memcontrol: catch root bypass in move precharge Date: Wed, 30 Apr 2014 16:25:38 -0400 Message-Id: <1398889543-23671-5-git-send-email-hannes@cmpxchg.org> X-Mailer: git-send-email 1.9.2 In-Reply-To: <1398889543-23671-1-git-send-email-hannes@cmpxchg.org> References: <1398889543-23671-1-git-send-email-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When mem_cgroup_try_charge() returns -EINTR, it bypassed the charge to the root memcg. But move precharging does not catch this and treats this case as if no charge had happened, thus leaking a charge against root. Because of an old optimization, the root memcg's res_counter is not actually charged right now, but it's still an imbalance and subsequent patches will charge the root memcg again. Thus, catch those bypasses to the root memcg and properly cancel them before giving up the move. Signed-off-by: Johannes Weiner --- mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index c431a30280ac..788be26103f9 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -6546,8 +6546,9 @@ one_by_one: cond_resched(); } ret = mem_cgroup_try_charge(memcg, GFP_KERNEL, 1, false); + if (ret == -EINTR) + __mem_cgroup_cancel_charge(root_mem_cgroup, 1); if (ret) - /* mem_cgroup_clear_mc() will do uncharge later */ return ret; mc.precharge++; } -- 1.9.2