systemd relies on CONFIG_CGROUP=y, since it useses it for service
management. It creates its own name=systemd hierarchy for that with no
controllers attached. If you turn that off, then systemd will refuse to
boot. However, it does not rely on any of the controllers, and hence you
are welcome to disable all cgroup controlls and systemd won't complain.
If you want to disable the automatic creation of groups in the 'cpu'
hierarchy for user sessions then you can tell pam_systemd that by passing
"controllers=" on the PAM config line. ("controllers=cpu" is the implied
default.)
There's currently no global option to disable the same logic in systemd
when it creates 'cpu' cgroups for the various services it runs. However,
you can disable that individually with "ControlGroups=cpu:/" in the
.service files. I will now add a global option as well.
Lennart
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Lennart Poettering - Red Hat, Inc.
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