Re: [PATCH 1/4] cgroup freezer: Fix buggy resume test for tasks frozen with cgroup freezer

[Matt Helsley <matthltc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org>]

On Thu, Jun 04, 2009 at 08:55:17AM +0800, Li Zefan wrote:
> Serge E. Hallyn wrote:
> > Quoting Matt Helsley (matthltc-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org):
> >> -int cgroup_frozen(struct task_struct *task)
> >> +int cgroup_freezing_or_frozen(struct task_struct *task)
> >>  {
> >>  	struct freezer *freezer;
> >>  	enum freezer_state state;
> >>
> >>  	task_lock(task);
> >>  	freezer = task_freezer(task);
> >> -	state = freezer->state;
> >> +	if (!freezer->css.cgroup->parent)
> >> +		state = CGROUP_THAWED; /* root cgroup can't be frozen */
> >> +	else
> >> +		state = freezer->state;
> > 
> > Why do you have to add this special-casing now?  I thought
> > we were already preventing freezing the root cgroup, so
> > freezer->state should be sane in that case anyway?
> > 
> 
> Yeah, IIRC top_freezer->state is alwasy CGROUP_THAWED, so this
> check is redundant.

Right, fixed.

Cheers,
	-Matt