From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756461AbYKUIyp (ORCPT ); Fri, 21 Nov 2008 03:54:45 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753439AbYKUIwl (ORCPT ); Fri, 21 Nov 2008 03:52:41 -0500 Received: from cn.fujitsu.com ([222.73.24.84]:49400 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1753182AbYKUIwj (ORCPT ); Fri, 21 Nov 2008 03:52:39 -0500 Message-ID: <4926761B.2060608@cn.fujitsu.com> Date: Fri, 21 Nov 2008 16:49:31 +0800 From: Lai Jiangshan User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) MIME-Version: 1.0 To: Andrew Morton , Paul Menage , Linux Kernel Mailing List , Linux Containers Subject: [PATCH] cgroups: defer free css_set Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org we free css_set when refcnt became 0 immediately(except cgroup_attach_task()). I will destroy the data which read side maybe still access it. this patch use call_rcu() to defer free css_set Signed-off-by: Lai Jiangshan --- diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index 1164963..22901ff 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -178,6 +178,8 @@ struct css_set { */ struct list_head cg_links; + struct rcu_head rcu; + /* * Set of subsystem states, one for each subsystem. This array * is immutable after creation apart from the init_css_set diff --git a/kernel/cgroup.c b/kernel/cgroup.c index 358e775..ddc10ac 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -252,6 +252,11 @@ static void unlink_css_set(struct css_set *cg) } } +static void rcu_free_css_set(struct rcu_head *head) +{ + kfree(container_of(head, struct css_set, rcu)); +} + static void __put_css_set(struct css_set *cg, int taskexit) { int i; @@ -281,7 +286,7 @@ static void __put_css_set(struct css_set *cg, int taskexit) } } rcu_read_unlock(); - kfree(cg); + call_rcu(&cg->rcu, rcu_free_css_set); } /* @@ -1267,7 +1277,6 @@ int cgroup_attach_task(struct cgroup *cgrp, struct task_struct *tsk) ss->attach(ss, cgrp, oldcgrp, tsk); } set_bit(CGRP_RELEASABLE, &oldcgrp->flags); - synchronize_rcu(); put_css_set(cg); return 0; }