Re: [PATCH cgroup/for-3.11 1/3] cgroup: mark "tasks" cgroup file as insane

[Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>]

On Tue, Jun 04, 2013 at 01:21:39PM +0200, Michal Hocko wrote:
> On Mon 03-06-13 19:13:02, Tejun Heo wrote:
> > Some resources controlled by cgroup aren't per-task and cgroup core
> > allowing threads of a single thread_group to be in different cgroups
> > forced memcg do explicitly find the group leader and use it.  This is
> > gonna be nasty when transitioning to unified hierarchy and in general
> > we don't want and won't support granularity finer than processes.
> > 
> > Mark "tasks" with CFTYPE_INSANE.
> 
> Hmm, I wasn't aware that procs is a better interface to work with
> entities in the group so I was using tasks which worked well for memcg.
> I am afraid I am not the only one. Can we get a warning when somebody
> opens the file?
> 
> That being said, I do not object against removal, please just add a
> warning to let people know that procs is a preferred interface.

Hmmm... I don't know.  For users of multiple hierarchies, tasks are
fine.  It's only gonna be an issue when we transition to unified
hierarchy where a lot of other things would change too.  I'm not sure
whether it'd be worthwhile to generate a warning now for everyone.
Li, what do you think?

Thanks.

-- 
tejun