[libvirt] [PATCH 3/3] qemu: Prohibit chaning affinity of domain process if placement is 'auto'

[Osier Yang]

On 2012年10月24日 21:45, Osier Yang wrote:
> On 2012年10月24日 21:38, Martin Kletzander wrote:
>> On 10/24/2012 12:00 PM, Osier Yang wrote:
>>> On one hand, numad probably will manage the affinity of domain process
>>> dynamically in future. On the other hand, even numad won't manage it,
>>
>> s/even/even if/
>>
>>> it still could confusion. Let's make things simpler enough to avoid
>>
>> s/could/could cause/
>>
>>> the lair for now.
>>> ---
>>> src/qemu/qemu_driver.c | 7 +++++++
>>> 1 files changed, 7 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
>>> index 8af316f..254f191 100644
>>> --- a/src/qemu/qemu_driver.c
>>> +++ b/src/qemu/qemu_driver.c
>>> @@ -4204,6 +4204,13 @@ qemudDomainPinEmulator(virDomainPtr dom,
>>> goto cleanup;
>>> }
>>>
>>> + if (vm->def->placement_mode == VIR_DOMAIN_CPU_PLACEMENT_MODE_AUTO) {
>>> + virReportError(VIR_ERR_OPERATION_INVALID, "%s",
>>> + _("Changing affinity for emulator thread dynamically "
>>> + "is not allowed when CPU placement is 'auto'"));
>>> + goto cleanup;
>>> + }
>>> +
>>> if (virDomainLiveConfigHelperMethod(driver->caps, vm,&flags,
>>> &persistentDef)< 0)
>>> goto cleanup;
>>>
>>
>> We should unify if the vcpu pinning is only meant for starting the
>> domain or if it's mandatory for the whole time domain is running. It is
>> possible now to have auto placement and pin the vcpus while the domain
>> is running.
>>
>> If we want to disable it for emulator threads, we should also do it for
>> VCPU threads.
>
> IMO no need to disable for vCPU threads, as "auto" placement only
> cares about the affinity of domain process, it might imply we should
> change that, but now it is that.

I'm fine to keep this patch in the list though, it's not that hurry to
get it in.

>
> However, then decision whether we should do it at all
>> should not be made by me. Anyone else has an opinion on that?
>>
>> Martin
>
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