[CRIU] [PATCH 1/2] cgroups: Add ability to reuse existing cgroup yard directory

[Tycho Andersen]

On Fri, Jun 12, 2015 at 08:47:48AM +0300, Cyrill Gorcunov wrote:
> On Thu, Jun 11, 2015 at 09:31:30PM -0600, Tycho Andersen wrote:
> > On Thu, Jun 11, 2015 at 08:04:02PM +0300, Cyrill Gorcunov wrote:
> > > Currently we always create temporary directory where we restore
> > > cgroups, but this won't work in case if mounting cgroups is forbidden
> > > from inside of a container for some reason (as in OpenVZ kernel).
> > > 
> > > So one can pass --cgroup-yard option to specify an existing
> > > directory where cgroups are living. By default we assume it
> > > lays in /sys/fs/cgroup.
> > 
> > I thought we chose not to use /sys/fs/cgroup originally because
> > someone could unmount it from underneath us?
> 
> Never headr of such thing. Still one can pass --cgroup-yard option
> and define the directory to use instead of /sys/fs/cgroup (it should
> be premounted by caller then).

Right, of course, it's just a change in the default behavior. I
thought there was some reason we didn't use /sys/fs/cgroup in the
first place, but I can't remember what it is.

Tycho