[libvirt] [PATCH v5 1/3] add new virDomainCoreDumpWithFormat API

[qiaonuohan at cn.fujitsu.com]

On 03/13/2014 03:42 PM, Martin Kletzander wrote:
> On Wed, Mar 12, 2014 at 09:29:55AM -0600, Eric Blake wrote:
>> On 03/12/2014 09:04 AM, Martin Kletzander wrote:
>>> On Thu, Mar 06, 2014 at 09:35:47AM +0000, qiaonuohan at cn.fujitsu.com wrote:
>>>> --memory-only option is introduced without compression supported. Therefore,
>>>> this is a freature regression of virsh dump. Now qemu has support dumping memory
>>>
>>> s/freature/feature/
>>>
>>> but I would not use the word "regression" since that never worked.
>>> Also it would help mentioning the commit ID or a version it
>>> got included in qemu.  On that note, is there a possibility of
>>> of introspection of that feature, so we can gracefully error out in
>>> case older qemu is used?
>>
>> Yes - qemu 2.0 is adding 'query-dump-guest-memory-capability', which can
>> be used for two purposes: 1. if this command exists, 'dump-guest-memory'
>> supports the new optional 'format' argument; and 2. calling this command
>> will return a list of WHICH formats are supported by the given qemu
>> binary (since configure-time choices can disable some of the formats
>> from actually working).  So you need to have a patch that modifies
>> src/qemu/qemu_capabilities.[ch] to do the probing and set capability
>> bits, so that we can gracefully error out when talking to a too-old
>> qemu, or requesting a format that was not compiled in to a new qemu.
>>
>
> Great.  Could we have the compression parameter just as an arbitrary
> string then (properly checked for, etc.) so there is no need to adapt
> our code to qemu format additions?
>
>>
>>>
>>> Looking at the rest, I rather fixed what I wanted to change in my repo
>>> and here's the diff I'd squash in.  Let me know if you're OK with
>>> that.  I'll still want an ACK from someone in order to push that,
>>> though.  And feel free to ask about that changes as well.
>>
>> I suppose the capability detection could be done as an add-on patch, but
>> I'm personally thinking it's better to hold off on this series until ALL
>> the work is done, so we don't forget to do the capability detection work.
>>
>
> Definitely, I just asked this question in the wrong patch, the
> detection and use of the capability should be in 2/3 or in separate
> one.
>
> Martin

Now, I am trying to find out how to do the probing and it will reflect on v6.
Thanks for point it out.

-- 
Regards
Qiao Nuohan