From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx183.postini.com [74.125.245.183]) by kanga.kvack.org (Postfix) with SMTP id C11C26B0070 for ; Fri, 19 Oct 2012 05:33:50 -0400 (EDT) Message-ID: <50811E5E.1090205@huawei.com> Date: Fri, 19 Oct 2012 17:33:18 +0800 From: Li Zefan MIME-Version: 1.0 Subject: Re: [PATCH 4/6] cgroups: forbid pre_destroy callback to fail References: <1350480648-10905-1-git-send-email-mhocko@suse.cz> <1350480648-10905-5-git-send-email-mhocko@suse.cz> In-Reply-To: <1350480648-10905-5-git-send-email-mhocko@suse.cz> Content-Type: text/plain; charset="GB2312" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Michal Hocko Cc: linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Tejun Heo , Johannes Weiner , KAMEZAWA Hiroyuki , Balbir Singh On 2012/10/17 21:30, Michal Hocko wrote: > Now that mem_cgroup_pre_destroy callback doesn't fail finally we can > safely move on and forbit all the callbacks to fail. The last missing > piece is moving cgroup_call_pre_destroy after cgroup_clear_css_refs so > that css_tryget fails so no new charges for the memcg can happen. > The callbacks are also called from within cgroup_lock to guarantee that > no new tasks show up. I'm afraid this won't work. See commit 3fa59dfbc3b223f02c26593be69ce6fc9a940405 ("cgroup: fix potential deadlock in pre_destroy") > We could theoretically call them outside of the > lock but then we have to move after CGRP_REMOVED flag is set. > > Signed-off-by: Michal Hocko > --- > kernel/cgroup.c | 30 +++++++++--------------------- > 1 file changed, 9 insertions(+), 21 deletions(-) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org