Re: [libvirt] [PATCH 05/18] Don't create dirs in cgroup controllers we don't want to use

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; Currently when getting an instance of virCgroupPtr we will create the path in all cgroup controllers. Only at the virt driver layer are we attempting to filter controllers. This is bad because the mere act of creating the dirs in the controllers can have a functional impact on the kernel, particularly for performance. Update the virCgroupForDriver() method to accept a bitmask of controllers to use. Only create dirs in the controllers that are requested. When creating cgroups for domains, respect the active controller list from the parent cgroup Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; ---

+++ b/src/lxc/lxc_cgroup.c @@ -530,7 +530,7 @@ virCgroupPtr virLXCCgroupCreate(virDomainDefPtr def) int ret = -1; int rc; - rc = virCgroupForDriver("lxc", &driver, 1, 0); + rc = virCgroupForDriver("lxc", &driver, 1, 0, -1);

+++ b/src/qemu/qemu_conf.c @@ -134,14 +134,7 @@ virQEMUDriverConfigPtr virQEMUDriverConfigNew(bool privileged) } cfg->dynamicOwnership = privileged; - cfg->cgroupControllers = - (1 << VIR_CGROUP_CONTROLLER_CPU) | - (1 << VIR_CGROUP_CONTROLLER_DEVICES) | - (1 << VIR_CGROUP_CONTROLLER_MEMORY) | - (1 << VIR_CGROUP_CONTROLLER_BLKIO) | - (1 << VIR_CGROUP_CONTROLLER_CPUSET) | - (1 << VIR_CGROUP_CONTROLLER_CPUACCT); - + cfg->cgroupControllers = -1; /* -1 == auto-detect */