From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx125.postini.com [74.125.245.125]) by kanga.kvack.org (Postfix) with SMTP id 8C7D56B0005 for ; Mon, 8 Apr 2013 22:51:59 -0400 (EDT) Received: from m3.gw.fujitsu.co.jp (unknown [10.0.50.73]) by fgwmail5.fujitsu.co.jp (Postfix) with ESMTP id D6AE53EE0C8 for ; Tue, 9 Apr 2013 11:51:57 +0900 (JST) Received: from smail (m3 [127.0.0.1]) by outgoing.m3.gw.fujitsu.co.jp (Postfix) with ESMTP id B6B8645DEBE for ; Tue, 9 Apr 2013 11:51:57 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (s3.gw.fujitsu.co.jp [10.0.50.93]) by m3.gw.fujitsu.co.jp (Postfix) with ESMTP id 9D2BF45DEB6 for ; Tue, 9 Apr 2013 11:51:57 +0900 (JST) Received: from s3.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 761571DB8043 for ; Tue, 9 Apr 2013 11:51:57 +0900 (JST) Received: from m1000.s.css.fujitsu.com (m1000.s.css.fujitsu.com [10.240.81.136]) by s3.gw.fujitsu.co.jp (Postfix) with ESMTP id 22B711DB803E for ; Tue, 9 Apr 2013 11:51:57 +0900 (JST) Message-ID: <5163823B.4020109@jp.fujitsu.com> Date: Tue, 09 Apr 2013 11:51:39 +0900 From: Kamezawa Hiroyuki MIME-Version: 1.0 Subject: Re: [PATCH 04/12] memcg, kmem: fix reference count handling on the error path References: <5162648B.9070802@huawei.com> <516264D6.3090100@huawei.com> In-Reply-To: <516264D6.3090100@huawei.com> Content-Type: text/plain; charset=GB2312 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Li Zefan Cc: Andrew Morton , Tejun Heo , Glauber Costa , Johannes Weiner , LKML , Cgroups , linux-mm@kvack.org (2013/04/08 15:33), Li Zefan wrote: > From: Michal Hocko > > mem_cgroup_css_online calls mem_cgroup_put if memcg_init_kmem > fails. This is not correct because only memcg_propagate_kmem takes an > additional reference while mem_cgroup_sockets_init is allowed to fail as > well (although no current implementation fails) but it doesn't take any > reference. This all suggests that it should be memcg_propagate_kmem that > should clean up after itself so this patch moves mem_cgroup_put over > there. > > Unfortunately this is not that easy (as pointed out by Li Zefan) because > memcg_kmem_mark_dead marks the group dead (KMEM_ACCOUNTED_DEAD) if it > is marked active (KMEM_ACCOUNTED_ACTIVE) which is the case even if > memcg_propagate_kmem fails so the additional reference is dropped in > that case in kmem_cgroup_destroy which means that the reference would be > dropped two times. > > The easiest way then would be to simply remove mem_cgrroup_put from > mem_cgroup_css_online and rely on kmem_cgroup_destroy doing the right > thing. > > Signed-off-by: Li Zefan > Signed-off-by: Michal Hocko > Cc: # 3.8.x Acked-by: KAMEZAWA Hiroyuki -- 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