[CRIU] [PATCH 1/2] Re-create cgroups if necessary

[Serge Hallyn]

Quoting Filipe Brandenburger (filbranden at google.com):
> Hi,
> 
> On Wed, Jun 25, 2014 at 8:21 AM, Pavel Emelyanov <xemul at parallels.com> wrote:
> > First, on dump all cgroup paths are dumped relative to root task groups.
> > It's not so yet, but since we in -rc we can change that. Next, on restore
> > we tell the --cgroup-root $path option that would prepend $path to all
> > cgroup paths from the image.
> 
> Do we need to consider the case where children tasks are actually in
> *sibling* cgroups?

My thought was that this would be refused at checkpoint, or we could
simply tag it as not-movable.  Bc at some point we cannot do anything
sane at restore :)

> Maybe it would make sense to map cgroup names into tags in dump and
> restore just like the ext-mount support does...
> 
> I'm really wondering if it wouldn't be easier to handle the cgroup
> hierarchy through external plug-ins, considering each container
> solution seems to have their own idea of how to manage cgroups.

That's probably fine - it'll have to be pluggable somehow, I was
just going to do it internally, automatically detected, rather
than external (and presumably guided by the cli options).