Looking up cgroups v2 on a Linux system

First, let's look up the available v2 controllers; to do so, locate the cgroups v2 mount point; it's usually here:

$ mount | grep cgroup2 
cgroup2 on /sys/fs/cgroup/unified type cgroup2 
   (rw,nosuid,nodev,noexec,relatime,nsdelegate) 
$ sudo cat /sys/fs/cgroup/unified/cgroup.controllers 
$ 

Hey, there aren't any controllers present in cgroup2!? Actually, it will be this way in the presence of mixed cgroups, v1 and v2, which is the default (as of the time of writing). To exclusively make use of the later version – and thus have all configured controllers visible – you must first disable cgroups v1 by passing this kernel command-line parameter at boot: cgroup_no_v1=all (recall, all available kernel parameters can be conveniently seen here: https://www.kernel.org/doc/Documentation/admin-guide/kernel-parameters.txt).

After rebooting the system with the preceding option, you can check that the kernel parameters you...