Messages in this thread | | | Date | Mon, 10 Oct 2011 10:34:26 -0700 | From | Tejun Heo <> | Subject | Re: [PATCH 1/4] cgroup: change locking order in attach_task_by_pid() |
| |
Hello,
On Sun, Sep 18, 2011 at 08:56:21PM +0200, Oleg Nesterov wrote: > On 09/05, Tejun Heo wrote: > > > > cgroup_mutex is updated to nest inside threadgroup_fork_lock instead > > of the other way around. threadgroup locking is scheduled to be > > updated to cover all threadgroup altering operations and nesting it > > inside cgroup_mutex complicates locking dependency unnecessarily. > > Could you please explain this change? > > I can't understand why threadgroup_lock() under cgroup_mutex is bad. > Do you mean we can deadlock otherwise?
Yeah, I forgot the chain but it triggers a valid lockdep deadlock warning.
> And, this means we can't change cpuset_do_move_task() to do > threadgroup_lock().
Would that be problematic?
Thanks.
-- tejun
| |