Re: [RFC][PATCH] cgroup: disallow subtree controller enable/disable while there are tasks

From: Tejun Heo
Date: Mon May 04 2015 - 12:15:13 EST


On Mon, May 04, 2015 at 06:11:29PM +0800, Zefan Li wrote:
> It's not safe if we enable/disable some controllers while there are
> tasks in the substree, because task migration can fail.
>
> For example rt bandwidth controller disallow having rt tasks in the
> cgroup if no bandwidth has been allocated, which is the case when
> a cgroup is just created.
>
> A kernel warning is triggered immediately by doing:

Well, the whole thing is behind the devel flag for a reason. Let's
see how we can resolve the RT case and then determine what to do.

Thanks.

--
tejun
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