Thanks for the comments Eric.
The offline, removes the entry from the cgroups and all its subcgroups.
On Online, I guess kernel does not know till which sub-cgroup it
should add the entry.
I think that is how cgroup is designed to behave when it lacks the
policy knowledge.
Let me know what you think.
Regards,
Shivaprasad G Bhat
On Fri, Jan 31, 2014 at 9:58 PM, Eric Blake <eblake@xxxxxxxxxx> wrote:
> On 01/31/2014 12:22 AM, Shivaprasad G Bhat wrote:
>> Online/Offline operations on the host cpus removes the machine/cpuset.cpus
>> which are never added back. The guests with vcpu pinning can fail to boot
>> unless the xml is edited.
>>
>> If the possibility that the offlined cpus are onlined back, the cpuset.cpus can be updated upon start of the guest thus allowing the guests to boot back without
>> erroring out.
>
> Please wrap commit message lines; typically, wrapping less than 70
> characters since 'git log' indents the lines.
>
>>
>> Signed-off-by: Shivaprasad G Bhat <sbhat@xxxxxxxxxxxxxxxxxx>
>> ---
>> src/util/vircgroup.c | 27 +++++++++++++++++----------
>> 1 file changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
>> index a6d60c5..52575c9 100644
>> --- a/src/util/vircgroup.c
>> +++ b/src/util/vircgroup.c
>> @@ -72,6 +72,7 @@ typedef enum {
>> * before creating subcgroups and
>> * attaching tasks
>> */
>> + VIR_CGROUP_CPUS_HIERACHY = 1 << 1, /* call virCgroupCpuSetInherit */
>
> s/HIERACHY/HIERARCHY/
>
> I'm not sure about the technical aspect of this patch, on whether this
> is the best approach to deal with the situation. I think the kernel has
> caused several issues with how it handles offline cpu vs. cgroups, and
> wonder if the fix belongs in the kernel.
>
> --
> Eric Blake eblake redhat com +1-919-301-3266
> Libvirt virtualization library http://libvirt.org
>
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