Re: [ckrm-tech] [PATCH 7/7] containers (V7): Container interface to nsproxy subsystem

Serge E. Hallyn
2007-04-02T14:09:46Z

Quoting Srivatsa Vaddagiri (vatsa@in.ibm.com):
> On Mon, Feb 12, 2007 at 12:15:28AM -0800, menage@google.com wrote:
> > +int ns_container_clone(struct task_struct *tsk)
> > +{
> > + return container_clone(tsk, &ns_subsys);
> > +}
>
> This function is a no-op if ns hierarchy is not mounted at this point.
> This would mean that we will miss out on some directories in ns
> hierarchy if it happened to be mounted later. It would be nice to
> recreate such missing directories upon mount. However I suspect it would
> not be easy ..Maybe we need to scan the task list and (re-)invoke
> ns_container_clone() for every new tsk->nsproxy we find in the list.
> Alternately perhaps we could auto mount (kern_mount) ns hierarchy very early at
> bootup? On the flip side that would require remount support so that additional
> controllers (like cpuset, mem) can be bound to (non-empty) ns hierarchy after
> bootup.

Losing the directory isn't a big deal though. And both unsharing a
namespace (which causes a ns_container_clone) and mounting the hierarchy
are done by userspace, so if for some installation it is a big deal,
the init scripts on initrd can mount the hierarchy before doing any
unsharing.

Can you think of a reason why losing a few directories matters?

-serge