Comment # 62 on bug 1159882 from Michal Hocko

(In reply to Robert Delahunt from comment #61)
> I'm just an average Joe, I don't even know what cgroups are for.

I would suspect some service has enabled the memory controller. Or maybe
systemd on your system does that but I believe that the version we have in
OS15.2 doesn't do that yet. Michal Koutny would know better and maybe give you
better clues how to find out.

For the general cgroups setup, please provide
mount | grep cgroup

Next steps will depend on the output.