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

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; 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.

Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- 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(-)