Hello, Waiman. On Mon, May 22, 2017 at 01:13:16PM -0400, Waiman Long wrote: > > Maybe I'm misunderstanding the design, but this seems to push the > > processes which belong to the threaded subtree to the parent which is > > part of the usual resource domain hierarchy thus breaking the no > > internal competition constraint. I'm not sure this is something we'd > > want. Given that the limitation of the original threaded mode was the > > required nesting below root and that we treat root special anyway > > (exactly in the way necessary), I wonder whether it'd be better to > > simply allow root to be both domain and thread root. > > Yes, root can be both domain and thread root. I haven't placed any > restriction on that. I've been playing with the proposed "make the parent resource domain". Unfortunately, the parent - child relationship becomes weird. The parent becomes the thread root, which means that its cgroup.threads file becomes writable and threads can be put in there. It's really weird to write to a child's interface and have the parent's behavior changed. This becomes weirder with delegation. If a cgroup is delegated, its cgroup.threads should be delegated too but if the child enables threaded mode, that makes the undelegated parent thread root, which means that either 1. the delegatee can't migrate threads to the thread root or 2. if the parent's cgroup.threads is writeable, the delegatee can mass with other descendants under it which shouldn't be allowed. I think the operation of making a cgroup a thread root should happen on the cgroup where that's requested; otherwise, nesting becomes too twisted. This should be solvable. Will think more about it. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
