Hi~
It seems that libvirt is not cpu hotplug aware.
Please refer to the following problem.
1. At first, we have 2 cpus.
# cat /cgroup/cpuset/cpuset.cpus
0-1
# cat /cgroup/cpuset/libvirt/qemu/cpuset.cpus
0-1
2. And we have a vm1 with following configuration.
<cputune>
<vcpupin vcpu='0' cpuset='1'/>
<hypervisorpin cpuset='1'/>
</cputune>
3. Offline cpu1.
# echo 0 > /sys/devices/system/cpu/cpu1/online
# cat /sys/devices/system/cpu/cpu1/online
0
# cat /cgroup/cpuset/cpuset.cpus
0
# cat /cgroup/cpuset/libvirt/qemu/cpuset.cpus
0
4. Online cpu1.
# echo 1 > /sys/devices/system/cpu/cpu1/online
# cat /sys/devices/system/cpu/cpu1/online
1
# cat /cgroup/cpuset/cpuset.cpus
0-1
# cat /cgroup/cpuset/libvirt/cpuset.cpus
0
# cat /cgroup/cpuset/libvirt/qemu/cpuset.cpus
0
# cat /cgroup/cpuset/libvirt/lxc/cpuset.cpus
0
Here，cgroup updated cpuset.cpus，but not for libvirt directory，and also qemu and lxc directory.
vm1 cannot be started again.
# virsh start vm1
error: Failed to start domain vm1
error: Unable to set cpuset.cpus: Permission denied
And libvird gave the following errors.
2012-07-17 07:30:22.478+0000: 3118: error : qemuSetupCgroupVcpuPin:498 : Unable to set cpuset.cpus: Permission denied
I am trying to use netlink socket with NETLINK_KOBJECT_UEVENT protocol to
listen to cpu hotplug events. But I met a little problem here.
virNetlinkEventServiceStart() only create a global variable server, and
create a NETLINK_ROUTE netlink socket for it.
So if I want to create another different netlink socket, such as NETLINK_KOBJECT_UEVENT,
what should I do ?
Shall we make the server global variable a global array ?
(It seems there are a lot of work to do.)
Thanks. :)
--
Best Regards,
Tang chen
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