Comment # 63 on bug 1159882 from Michal Koutn�

(In reply to Michal Hocko from comment #62)
> For the general cgroups setup, please provide
> mount | grep cgroup
Unless explicitly disabled (with kernel cmdline), the memory hierarchy (root
only) would be always mounted. To get the information about fine-grained
grouping, I suggest
> find /sys/fs/cgroup/memory -type d

Additionally, if there's a non-trivial structure, you can track the originating
service by looking at Memory* directives (MemoryDenyWriteExecute= is
irrelevant)
> systemctl cat "*.service" | grep -E "# /|Memory"