From mboxrd@z Thu Jan 1 00:00:00 1970 From: Glauber Costa Subject: bind() call in cgroup's css structure Date: Mon, 9 Apr 2012 10:59:56 -0300 Message-ID: <4F82EB5C.7090003@parallels.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Sender: cgroups-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-ID: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: Tejun Heo , Li Zefan , Paul Turner , cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "devel-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org" , linux-kernel Hello Tejun, During your cgroup refactor, I was wondering if you have any plans to get rid of the bind() callback that is called when hierarchies are moved? At least in tree, there seems to be no users for that. I actually planned to use it myself, to start or remove a jump label when cpuacct and cpu cgroups were comounted. Problem is, because we have some calls in the cpuset cgroup from inside the cpu hotplug handler, we end up taking the almighty cgroup_mutex from inside the cpu_hotplug.lock. jump labels take it in most arches through the get_online_cpus() function call. This means we effectively can't apply jump labels with the cgroup_mutex held, which is the case throughout the whole bind() call. All that explained, I figured I might as well ask before I attempted a solution to that myself: as much as populate(), bind seems to be one of the overly complicated callbacks, designed for a scenario in which everything can come and go at will, which is something we're trying to fix. thanks in advance for your answer!