"Serge E. Hallyn" <serge@xxxxxxxxxx> writes: > On Mon, Nov 16, 2015 at 09:50:55PM +0100, Richard Weinberger wrote: >> Am 16.11.2015 um 21:46 schrieb Serge E. Hallyn: >> > On Mon, Nov 16, 2015 at 09:41:15PM +0100, Richard Weinberger wrote: >> >> Serge, >> >> >> >> On Mon, Nov 16, 2015 at 8:51 PM, <serge@xxxxxxxxxx> wrote: >> >>> To summarize the semantics: >> >>> >> >>> 1. CLONE_NEWCGROUP re-uses 0x02000000, which was previously CLONE_STOPPED >> >>> >> >>> 2. unsharing a cgroup namespace makes all your current cgroups your new >> >>> cgroup root. >> >>> >> >>> 3. /proc/pid/cgroup always shows cgroup paths relative to the reader's >> >>> cgroup namespce root. A task outside of your cgroup looks like >> >>> >> >>> 8:memory:/../../.. >> >>> >> >>> 4. when a task mounts a cgroupfs, the cgroup which shows up as root depends >> >>> on the mounting task's cgroup namespace. >> >>> >> >>> 5. setns to a cgroup namespace switches your cgroup namespace but not >> >>> your cgroups. >> >>> >> >>> With this, using github.com/hallyn/lxc #2015-11-09/cgns (and >> >>> github.com/hallyn/lxcfs #2015-11-10/cgns) we can start a container in a full >> >>> proper cgroup namespace, avoiding either cgmanager or lxcfs cgroup bind mounts. >> >>> >> >>> This is completely backward compatible and will be completely invisible >> >>> to any existing cgroup users (except for those running inside a cgroup >> >>> namespace and looking at /proc/pid/cgroup of tasks outside their >> >>> namespace.) >> >>> cgroupns-root. >> >> >> >> IIRC one downside of this series was that only the new "sane" cgroup >> >> layout was supported >> >> and hence it was useless for everything which expected the default layout. >> >> Hence, still no systemd for us. :) >> >> >> >> Is this now different? >> > >> > Yes, all hierachies are no supported. >> > >> >> Should read "now"? :-) >> If so, *awesome*! > > D'oh! Yes, now :-) I am glad to see multiple hierarchy support, that is something people can use today. A couple of quick questions before I delve into a review. Does this allow mixing of cgroupfs and cgroupfs2? That is can I: "mount -t cgroupfs" inside a container and "mount -t cgroupfs2" outside a container? and still have reasonable things happen? I suspect the semantics of cgroups prevent this but I am interested to know what happens. Similary have you considered what it required to be able to safely set FS_USERNS_MOUNT? Eric -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
