Re: [Qemu-ppc] [Qemu-devel] [QEMU PATCH v5 3/6] migration: extend VMStateInfo

[Jianjun Duan]

On 10/13/2016 03:48 AM, Halil Pasic wrote:
> 
> 
> On 10/13/2016 10:22 AM, Paolo Bonzini wrote:
>>>> No, I disagree.  We shouldn't be worried about making intrusive changes
>>>>>> to all invocations or declarations, if that leads to a simpler API.
>>>>
>>>> If VMStateInfo was meant for complete customization, then it was missing
>>>> some parts. I think the API is indeed simpler. Just like
>>>> definition for VMStateField. Not all of its fields are used all time.
>> Code moves.  We can decide how much customization to allow of VMStateInfo.
>>
>> You said it: "Not all of its fields are used all time".  Likewise, not
>> all arguments are used all time for get/put, but it's not an issue if they
>> are still there!  So this patch is good, but at the same time VMS_LINKED is
>> pointless.
>>
>> Paolo
>>
> 
> I'm fine with this. I just think, it would be nice if the contract between
> the vmstate-core and the client code implementing VMStateInfo callbacks
> could be documented, including when are certain parameters valid, what
> they stand for, and how are they supposed to be used for the next version of
> the patch. Just to improve readability. Would this be OK with everybody?
> 
> By the way the flag VMS_SINGLE is documented as ignored. Should we drop
> it?
> 
I will prepare the VMStateInfo and QTAIL stuff as a separated series. If
indeed VMS_SINGLE is ignored, I can drop it here. It is similar to
VMS_LINKED situation.

Thanks,
Jianjun
>