[libvirt] [PATCH v3 12/16] Change default cgroup layout for QEMU/LXC and honour XML config

[Michal Privoznik]

On 10.04.2013 12:08, Daniel P. Berrange wrote:
> From: "Daniel P. Berrange" <berrange at redhat.com>
> 
> Historically QEMU/LXC guests have been placed in a cgroup layout
> that is
> 
>    $LOCATION-OF-LIBVIRTD/libvirt/{qemu,lxc}/$VMNAME
> 
> This is bad for a number of reasons
> 
>  - The cgroup hierarchy gets very deep which seriously
>    impacts kernel performance due to cgroups scalability
>    limitations.
> 
>  - It is hard to setup cgroup policies which apply across
>    services and virtual machines, since all VMs are underneath
>    the libvirtd service.
> 
> To address this the default cgroup location is changed to
> be
> 
>     /system/$VMNAME.{lxc,qemu}.libvirt
> 
> This puts virtual machines at the same level in the hierarchy
> as system services, allowing consistent policy to be setup
> across all of them.
> 
> This also honours the new resource partition location from the
> XML configuration, for example
> 
>   <resource>
>     <partition>/virtualmachines/production</partitions>
>   </resource>
> 
> will result in the VM being placed at
> 
>     /virtualmachines/production/$VMNAME.{lxc,qemu}.libvirt
> 
> NB, with the exception of the default, /system, path which
> is intended to always exist, libvirt will not attempt to
> auto-create the partitions in the XML. It is the responsibility
> of the admin/app to configure the partitions. Later libvirt
> APIs will provide a way todo this.

This NB part shall be duplicated to the docs from previous patch.

> 
> Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> ---
>  src/lxc/lxc_cgroup.c    |  91 +++++++++++++++++++++++++++++++-------
>  src/lxc/lxc_cgroup.h    |   2 +-
>  src/lxc/lxc_process.c   |   4 +-
>  src/qemu/qemu_cgroup.c  | 114 +++++++++++++++++++++++++++++++++++++-----------
>  src/qemu/qemu_cgroup.h  |   3 +-
>  src/qemu/qemu_process.c |   2 +-
>  6 files changed, 169 insertions(+), 47 deletions(-)

ACK

Michal