[systemd-devel] Systemd and cgroups

[Daniel P. Berrange]

On Wed, Apr 10, 2013 at 12:43:56PM +0300, Kevin Wilson wrote:
> Hello,
> I have a question about systemd and cgroups:
> "mount | grep cgroups" shows that only one entry has name=systemd.
> and is mounted on /sys/fs/cgroup/systemd . (see below the full output
> of "mount | grep cgroups"
> 
> Is it true that all other cgroup entry shown by "mount | grep cgroups"
> were not mounted by systemd (and may be unmounted without directly
> causing problems is systemd)?

If some 3rd party application has mounted cgroups controllers before
systemd starts, it will honour that setup. If they were not already
mounted, then systemd itself will mount all the resource controllers
that are compiled into the kernel.

Systemd will only actually create sub-dirs in those controllers
that are listed in the 'DefaultControllers' setting of systemd.conf,
which defaults to 'cpu'.

Daniel
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