[libvirt] [RFC] Support cpu hotplug in libvirt.

Viktor Mihajlovski mihajlov at linux.vnet.ibm.com
Wed Jul 18 11:47:42 UTC 2012

On 07/18/2012 12:53 PM, tangchen wrote:
> Hi Viktor:
> On 07/18/2012 05:06 PM, Viktor Mihajlovski wrote:
>> I was actually considering a workaround in libvirt for what I believe to be a
>> kernel misbehavior, however it is possible to deconfigure the cpuset controller
>> in the host (i.e. removing it from /etc/cgconfig.conf). The CPU pinning will
>> still work, only that it using the "legacy" taskset mechanism. All other
>> cgroup-related functionality continues to work as well.
>> One issue with monitoring the online state of cpus is that libvirtd might not
>> be running all the time (crash, update) and thus can miss hotplug events.
> I don't think remove cpuset controller from cgroup is a good idea.
> Maybe other apps will need it.

Maybe ... but a workaround in libvirt will not solve the other apps' issues ;-)
I still would maintain this has to be fixed in the kernel.

> So I am considering capture the hotplug event (which is uevent) with netlink.
> And change the behavior of cgroup in libvirt.
> How do you think ?

Looking forward to see a patch...

> Thanks. :)


Mit freundlichen Grüßen/Kind Regards
   Viktor Mihajlovski

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