Re: [libvirt] [PATCH 07/13] Create + setup cgroups atomically for QEMU process

From: "Daniel P. Berrange" <berrange(a)redhat.com&gt; Currently the QEMU driver creates the VM's cgroup prior to forking, and then uses a virCommand hook to move the child into the cgroup. This won't work with systemd whose APIs do the creation of cgroups + attachment of processes atomically. Fortunately we have a handshake taking place between the QEMU driver and the child process prior to QEMU being exec()d, which was introduced to allow setup of disk locking. By good fortune this synchronization point can be used to enable the QEMU drivedr to do atomic setup of cgroups removing the use

of the hook script. Signed-off-by: Daniel P. Berrange <berrange(a)redhat.com&gt; --- src/qemu/qemu_cgroup.c | 12 +++++++++--- src/qemu/qemu_process.c | 39 +++++++++++++++++---------------------- 2 files changed, 26 insertions(+), 25 deletions(-)