On Thu, Feb 26, 2009 at 10:40:54PM +0000, David Lutterkort wrote:
On Thu, 2009-02-26 at 16:36 +0000, Daniel P. Berrange wrote:
Recent Linux kernels have a new concept of 'CGroups' which is a way to group tasks on the system and apply policy to them as a whole. We already use this in the LXC container driver, to control total memory usage of things runing within a container.
This patch series is a proof of concept to make use of CGroups in the QEMU driver. The idea is that we have a 3 level cgroup hierarchy
- Top level; contains the libvirtd daemon itself - 2nd level: one per libvirt driver, but dos not contain any processes. - 3rd level: one per guest VM. Contains the QEMU process
Why the separate group for the driver ? Do you see partitioning of resources by driver as an important requirement ?
It is mostly a namespacing issue. The per-VM group names on the filesystem are based off the VM name. VM names are only unique within scope of a driver. Since both LXC and QEMU drivers use CGroups, we need to make sure they have separate namespace in cgroups. A per-driver cgroup solves this nicely. Daniel -- |: Red Hat, Engineering, London -o- http://people.redhat.com/berrange/ :| |: http://libvirt.org -o- http://virt-manager.org -o- http://ovirt.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: GnuPG: 7D3B9505 -o- F3C9 553F A1DA 4AC2 5648 23C1 B3DF F742 7D3B 9505 :|