[libvirt] [PATCH 2/5] qemu: Store supported migration capabilities in a bitmap

[John Ferlan]

On 10/20/2017 03:03 AM, Jiri Denemark wrote:
> On Thu, Oct 19, 2017 at 18:30:53 -0400, John Ferlan wrote:
>>
>>
>> On 10/18/2017 07:29 AM, Jiri Denemark wrote:
>>> Each time we need to check whether a given migration capability is
>>> supported by QEMU, we call query-migrate-capabilities QMP command and
>>> lookup the capability in the returned list. Asking for the list of
>>> supported capabilities once when we connect to QEMU and storing the
>>> result in a bitmap is much better and we don't need to enter a monitor
>>> just to check whether a migration capability is supported.
>>>
>>> Signed-off-by: Jiri Denemark <jdenemar at redhat.com>
>>> ---
>>>  src/qemu/qemu_domain.c  | 68 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>  src/qemu/qemu_domain.h  |  9 +++++++
>>>  src/qemu/qemu_process.c | 13 +---------
>>>  3 files changed, 78 insertions(+), 12 deletions(-)
>>>
>>
>> There's no corresponding adjustment to qemuDomainObjPrivateXMLFormat and
>> qemuDomainObjPrivateXMLParse in order to handle the restart scenario.
>>
>> The rest of this looks OK, but do you need the Format/Parse logic for
>> the bitmap?
> 
> No. The migration capabilities are rechecked every time libvirt connects
> to QEMU as said in the commit message and in qemu_domain.h:
> 

OK, so to be official...

Reviewed-by: John Ferlan <jferlan at redhat.com>

John

>>> diff --git a/src/qemu/qemu_domain.h b/src/qemu/qemu_domain.h
>>> index 5201c6a0ac..fb20d8ea63 100644
>>> --- a/src/qemu/qemu_domain.h
>>> +++ b/src/qemu/qemu_domain.h
>>> @@ -323,6 +323,10 @@ struct _qemuDomainObjPrivate {
>>>  
>>>      /* Tracks blockjob state for vm. Valid only while reconnecting to qemu. */
>>>      virTristateBool reconnectBlockjobs;
>>> +
>>> +    /* Migration capabilities. Rechecked on reconnect, not to be saved in
>>> +     * private XML. */
>>> +    virBitmapPtr migrationCaps;
>>>  };
> 
> Jirka
>