[patch 1/2] Add clone_child control file

[Paul Menage]

On Mon, Dec 28, 2009 at 3:04 PM, Daniel Lezcano <daniel.lezcano at free.fr> wrote:
> This patch is sent as an answer to a previous thread around the ns_cgroup.
>
> https://lists.linux-foundation.org/pipermail/containers/2009-June/018627.html
>
> It adds a control file 'clone_children' for a cgroup.
> This control file is a boolean specifying if the child cgroup should
> be a clone of the parent cgroup or not. The default value is 'false'.
>
> This flag makes the child cgroup to call the post_clone callback of all
> the subsystem, if it is available.

Basic idea looks OK, and it seems like a plausible way to handle
automatic construction/inheritance of control values. I have a minor
worry that it might not be fine-grained enough though - are there
maybe cases where you'd want cloning for one subsystem but not for
others? I suppose in that case you can just put them on separate
hierarchies.

The file should be called cgroup.clone_children rather than plain
clone_children, to fit in with the other new generic-cgroup control
files that we've started introducing, and to avoid naming clashes.

Paul