Support for cgroup v2 is very similar to cgroup v1 just checking (and
writing) different file.
Testing this feature is a bit harder than with cgroup v1 so it's
probably worh noting in this commit message.
1. Copy some service file (I've used httpd service) and set
CPUQuota=30% in the [service] section.
2. Check /sys/fs/cgroup/cgroup.subtree_control - there should be no
"cpu"
3. Start modified service
4. Check /sys/fs/cgroup/cgroup.subtree_control - there should be "cpu"
5. Start corosync - It should be able to get rt priority
When move_to_root_cgroup is disabled, behavior differs:
- If corosync is started before modified service, so
there is no "cpu" in /sys/fs/cgroup/cgroup.subtree_control
corosync starts without problem and gets rt priority.
Starting modified service later will never add "cpu" into
/sys/fs/cgroup/cgroup.subtree_control (because corosync is holding
rt priority and it is placed in the non-root cgroup by systemd).
- When corosync is started after modified service, so "cpu"
is in /sys/fs/cgroup/cgroup.subtree_control, corosync is not
able to get RT priority.
Signed-off-by: Jan Friesse <jfriesse@redhat.com>
Reviewed-by: Christine Caulfield <ccaulfie@redhat.com>
57e6b86b53