From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 1E45E6B007D for ; Tue, 16 Dec 2008 06:35:30 -0500 (EST) Message-Id: <20081216113055.713856000@menage.corp.google.com> Date: Tue, 16 Dec 2008 03:30:55 -0800 From: menage@google.com Subject: [PATCH 0/3] CGroups: Hierarchy locking/refcount changes Sender: owner-linux-mm@kvack.org To: akpm@linux-foundation.org, kamezawa.hiroyu@jp.fujitsu.com, lizf@cn.fujitsu.com Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: These patches introduce new locking/refcount support for cgroups to reduce the need for subsystems to call cgroup_lock(). This will ultimately allow the atomicity of cgroup_rmdir() (which was removed recently) to be restored. These three patches give: 1/3 - introduce a per-subsystem hierarchy_mutex which a subsystem can use to prevent changes to its own cgroup tree 2/3 - use hierarchy_mutex in place of calling cgroup_lock() in the memory controller 3/3 - introduce a css_tryget() function similar to the one recently proposed by Kamezawa, but avoiding spurious refcount failures in the event of a race between a css_tryget() and an unsuccessful cgroup_rmdir() Future patches will likely involve: - using hierarchy mutex in place of cgroup_lock() in more subsystems where appropriate - restoring the atomicity of cgroup_rmdir() with respect to cgroup_create() Signed-off-by: Paul Menage -- -- 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