Comment # 68 on bug 1159882 from Robert Delahunt

I set up one window doing dd if=/dev/zero of=/dev/sdc bs=4K 
Another monitoring the output of df -h | grep cgroup every second
Another monitoring directories under /sys/fs/cgroup/memory
Another monitoring free -m

As expected, swap use spiked at roughly 200 MB (consider: I have 32 GB RAM)

At no time did cgroup get used or any directories populate under
/sys/fs/cgroup/memory

Understand that I have a long history with OpenSUSE memory issues.

In previous versions, I would put entries in /etc/fstab that forcefully
remounted all tmpfs mountpoints with a size=512M option to reduce their usage.

In the past, it seemed that helped my system use swap less, though I never
collected any scientific data that would empirically prove it helped.  It just
seemed that stock OpenSUSE (previous versions) dug into swap more readily, so
forcing tmpfs entries to use less space seemed to help.

I have long been suspicious of tmpfs reclaim anyways.

But regardless, it seems nothing is using cgroups.

I have also speculated that OpenSUSE needs a laptop-specific kernel which would
alter this behavior.  I mean, does anyone honestly need groups on a laptop?

Anyways, one minor note is the kernel you made, mhocko, results in me not
having a sound card.

But yeah, back to the original topic, cgroups isn't using anything, but the
machine dug into swap predictably, just like before.