Control groups manage resource use through kernel resource controllers. A kernel resource controller represents a single resource, such as CPU time, memory, network bandwidth, or disk I/O.

To identify mounted resource controllers in the system, check the contents of the /procs/cgroups file, for example:

less /proc/cgroups

#subsys_name    hierarchy       num_cgroups     enabled
cpuset  0       103     1
cpu     0       103     1
cpuacct 0       103     1
blkio   0       103     1
memory  0       103     1
devices 0       103     1
freezer 0       103     1
net_cls 0       103     1
perf_event      0       103     1
net_prio        0       103     1
hugetlb 0       103     1
pids    0       103     1
rdma    0       103     1
misc    0       103     1

For a detailed explanation of the kernel resource controllers of cgroups, see the cgroups(7) manual page.