Hello, Waiman. On Wed, Jun 14, 2017 at 11:05:35AM -0400, Waiman Long wrote: > Subtree root mode is a new cgroup mode which applies the following > restrictions when turned on: > > 1) Controllers are only allowed to be passed to the children in > bypass mode except those with the "enable_on_root" flag on. > 2) Only 1 child cgroup is allowed. > > That lone child can be used as the pseudo root of a container cgroup > hierarchy. All the resources, if controlled, are in the parent > cgroup. There will be no control knobs in the child. That makes it > look and feel like a root.
I'm not sure not having the control files in the child makes that much difference. > That pseudo root is also considered to be mixable and so can become > root of a mixed threaded subtree. The no internal process constraint > also does not apply. Heh, you can't just declare a non-root cgroup to be a mixed root but if you're special casing this and making the kernel play a masquerade with special node, you can make cgroup provide a mixed root while hosting the internal processes in a dedicated leaf cgroup which isn't visible to the nested root, right? It's all a game of masquerading tho and doesn't actually enable anything which isn't possible now. This would definitely be useful for testing. Thanks. -- tejun
