From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH 2/2 v3] cgroup: Drop task_lock(parent) on cgroup_fork() Date: Wed, 21 Dec 2011 11:16:24 -0800 Message-ID: <20111221191624.GK9213@google.com> References: <1324494199-23928-1-git-send-email-fweisbec@gmail.com> <1324494199-23928-3-git-send-email-fweisbec@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1324494199-23928-3-git-send-email-fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Frederic Weisbecker Cc: Containers , LKML , Oleg Nesterov , Mandeep Singh Baines , Cgroups , Andrew Morton , Paul Menage List-Id: containers.vger.kernel.org On Wed, Dec 21, 2011 at 08:03:19PM +0100, Frederic Weisbecker wrote: > We don't need to hold the parent task_lock() on the > parent in cgroup_fork() because we are already synchronized > against the two places that may change the parent css_set > concurrently: > > - cgroup_exit(), but the parent obviously can't exit concurrently > - cgroup migration: we are synchronized against threadgroup_lock() > > So we can safely remove the task_lock() there. > > Signed-off-by: Frederic Weisbecker > Cc: Tejun Heo > Cc: Li Zefan > Cc: Containers > Cc: Cgroups > Cc: KAMEZAWA Hiroyuki > Cc: Oleg Nesterov > Cc: Andrew Morton > Cc: Paul Menage > Cc: Mandeep Singh Baines Applied both patches to cgroup/for-3.3 and pushed out to linux-next. Thank you. -- tejun