Comment # 67 on bug 1159882 from Michal Hocko

(In reply to Robert Delahunt from comment #66)
[...]
> cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
[...]
> find /sys/fs/cgroup/memory -type d
> 
> /sys/fs/cgroup/memory

This is more than surprising. Because there are no cgroups created and as such
they cannot really influence the reclaim decisions. Could you try to reproduce
your original problem and see whether something/somebody creates any
directories (cgroups) in that hiearchy?