app-admin/cgmanager needs to be started with "-M name=openrc --allow-autoremove-premounted=all --autoremove-premounted-set-release-agent" in order to make it fully compatible with how OpenRC manages cgroups. These options should be added to "command_args" in /etc/init.d/cgmanager. Rationale for each option: * "-M name=openrc": "openrc" is the cgroup where OpenRC places its services. We surely don't want to add user sessions there and generally manage these cgroups behind OpenRC's back, * "--autoremove-premounted-set-release-agent": OpenRC premounts all cgroup v1 controllers at a system startup, but without setting any release agents for them. That's why cgmanager needs to set its own release agent there so empty cgroups under these controllers (including these created by cgmanager) don't linger around, * "--allow-autoremove-premounted=all": actually enables handling of removal-on-empty requests for these premounted cgroup v1 controllers. Without these two options above empty cgmanager user sessions don't get removed correctly. See also bug 593306 for an old bug caused by missing "-M name=openrc" options (although this is worked around in newer sys-auth/consolekit versions it is still a problem if using the more flexible pam_cgm instead of sys-auth/consolekit's built-in session cgroups support). I am reporting this "bug" not only as a user of this package but also as the person who added the above command line options upstream and personally uses them for 1.5+ year now for per-session cgroup management using pam_cgm.
