cgroup: status-quo and userland efforts

[Andy Lutomirski]

On 06/27/2013 11:01 AM, Tejun Heo wrote:
> AFAICS, having a userland agent which has overall knowledge of the
> hierarchy and enforcesf structure and limiations is a requirement to
> make cgroup generally useable and useful.  For systemd based systems,
> systemd serving that role isn't too crazy.  It's sure gonna have
> teeting issues at the beginning but it has all the necessary
> information to manage workloads on the system.
> 
> A valid issue is interoperability between systemd and non-systemd
> systems.  I don't have an immediately good answer for that.  I wrote
> in another reply but making cgroup generally available is a pretty new
> effort and we're still in the process of figuring out what the right
> constructs and abstractions are.  Hopefully, we'll be able to reach a
> common set of abstractions to base things on top in itme.
> 

The systemd stuff will break my code, too (although the single hierarchy
by itself won't, I think).  I think that the kernel should make whatever
simple changes are needed so that systemd can function without using
cgroups at all.  That way users of a different cgroup scheme can turn
off systemd's.

Here was my proposal, which hasn't gotten a clear reply:

http://article.gmane.org/gmane.comp.sysutils.systemd.devel/11424

I've already sent a patch to make /proc/<pid>/task/<tid>/children
available regardless of configuration.

--Andy