From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753187AbZHKA6W (ORCPT ); Mon, 10 Aug 2009 20:58:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753061AbZHKA6S (ORCPT ); Mon, 10 Aug 2009 20:58:18 -0400 Received: from smtp-out.google.com ([216.239.33.17]:21431 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751987AbZHKA6Q (ORCPT ); Mon, 10 Aug 2009 20:58:16 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=from:subject:to:date:message-id:in-reply-to:references: user-agent:mime-version:content-type:content-transfer-encoding; b=TE94eM4kZzZBErYP+EOQBqnKIf81DkXtSHk210dtE7jiwZiOjI0oOSe+B5unov/wI dgE30k8OgMoKlMTn37tdw== From: Ben Blum Subject: [PATCH 4/7] Changes css_set freeing mechanism to be under RCU To: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org, akpm@linux-foundation.org, serue@us.ibm.com, lizf@cn.fujitsu.com, menage@google.com, bblum@google.com Date: Mon, 10 Aug 2009 17:57:51 -0700 Message-ID: <20090811005751.21950.42347.stgit@hastromil.mtv.corp.google.com> In-Reply-To: <20090811004737.21950.29188.stgit@hastromil.mtv.corp.google.com> References: <20090811004737.21950.29188.stgit@hastromil.mtv.corp.google.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 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 Changes css_set freeing mechanism to be under RCU This is a prepatch for making the procs file writable. In order to free the old css_sets for each task to be moved as they're being moved, the freeing mechanism must be RCU-protected, or else we would have to have a call to synchronize_rcu() for each task before freeing its old css_set. Signed-off-by: Ben Blum --- include/linux/cgroup.h | 3 +++ kernel/cgroup.c | 8 +++++++- 2 files changed, 10 insertions(+), 1 deletions(-) diff --git a/include/linux/cgroup.h b/include/linux/cgroup.h index b934b72..24e3f1a 100644 --- a/include/linux/cgroup.h +++ b/include/linux/cgroup.h @@ -260,6 +260,9 @@ struct css_set { * during subsystem registration (at boot time). */ struct cgroup_subsys_state *subsys[CGROUP_SUBSYS_COUNT]; + + /* For RCU-protected deletion */ + struct rcu_head rcu_head; }; /* diff --git a/kernel/cgroup.c b/kernel/cgroup.c index f6d5969..a12bc8e 100644 --- a/kernel/cgroup.c +++ b/kernel/cgroup.c @@ -288,6 +288,12 @@ static void unlink_css_set(struct css_set *cg) } } +static void free_css_set_rcu(struct rcu_head *obj) +{ + struct css_set *cg = container_of(obj, struct css_set, rcu_head); + kfree(cg); +} + static void __put_css_set(struct css_set *cg, int taskexit) { int i; @@ -317,7 +323,7 @@ static void __put_css_set(struct css_set *cg, int taskexit) } } rcu_read_unlock(); - kfree(cg); + call_rcu(&cg->rcu_head, free_css_set_rcu); } /*