On Thu, Aug 27, 2015 at 04:27:22PM -0400, Tejun Heo wrote: > Hello, > > On Thu, Aug 27, 2015 at 03:21:37PM -0500, Serge E. Hallyn wrote: > > The problem this would solve is running older userspace (i.e. libvirt in > > a container running an older distro) on a newer kernel which has unified > > hierarchy mounted. > > But the leaf restriction isn't the only change. The interface files That was an example. It would also have to automatically enable controllers in child cgroups, and I'm not sure what to do about the tasks file. > are different too and for some controllers the basic operation model > is different, so I don't see how just adding .leaf would do much good. Yeah and some of these may be a problem, but the problems I outlined above are the ones which are *really* breaking old userspace. Keeping in mind what I've seen most people use for containers, what I've seen in the Documentation/cgroups/unified.txt file shouldn't be too terrible. My last test was on 3.19.0-18-generic and I assume it gets worse, and we'll need to proxy attempts at memory limit setting, for instance. > If the legacy userspace doesn't do any resource control, the leaf rule > restriction doesn't apply anyway, so nothing to worry about. My main use case is nested lxc, presumably with systemd inside some of the nested containers, so this would definately be an issue. -serge -- To unsubscribe from this list: send the line "unsubscribe cgroups" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
