[systemd-devel] systemd, cgroups and process swappiness

[Dennis Jacobfeuerborn]

Hi,
I'm trying to prevent a qemu process from using swap and noticed that in
addition to /proc/sys/vm/swappiness systemd and cgroups now play a role
in this.

I set /proc/sys/vm/swappiness to 0 and did the same for
/sys/fs/cgroup/memory/machine.slice/memory.swappiness and
/sys/fs/cgroup/memory/machine.slice/<qemu-process>/memory.swappiness yet
when i look at look at the VmSwap values for the process it still goes
up sometimes indicating that more swap space is used:

[root at virt7 machine.slice]# cat /proc/31655/status|grep VmSwap
VmSwap:	 3725508 kB

I noticed that some values can be set using "systemctl set-property" but
memory.swappiness does not seem to be among them so i used "echo 0 >
..." to set the above values.

Is there something else that needs to be done to apply these values to
the running process?

Regards,
  Dennis