The machine cgroup is a superset, a parent to the emulator and vcpuX
cgroups. The parent cgroup should never have any tasks directly in it.
In fact the parent cpuset might contain way more cpus than the sum of
emulatorpin and vcpupins. So putting tasks in the superset will allow
them to run outside of <cputune>.
Signed-off-by: NHenning Schild <henning.schild@siemens.com>