Re: [Qemu-devel] [PATCH v11 14/15] rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition

["Michael R. Hines" <mrhines@linux.vnet.ibm.com>]

On 06/26/2013 10:57 AM, Paolo Bonzini wrote:
> Il 26/06/2013 16:09, Michael R. Hines ha scritto:
>> *This requires some steps:*
>> 1. First, maintain a new data structure: something like
>>      "These memory ranges are 'being unpinned'" - block all potential writes
>>      to these addresses until the unpinning completes.
>> 2. Once the source unpin completes, send the asynchronous control
>> channel message
>>      to the other side for unpinning.
>> 2. Mark the data structure and return and allow the migration to continue
>>      with the next RDMA write.
>> 3. Upon completion of the unpinning on the destination,
>>      respond to the source that it was finished.
>> 4. Source then clears the data structure for the successfully unpinned
>> memory ranges.
>> 5. At this point, one or more writes may (or may not) be blocking on the
>>      unpinned memory areas and will poll the data structure and find that
>>      the unpinning has completed.
>> 6. Then issue the new writes and proceed as normal.
>> 7. Repeat step 1.
> After more discussion on IRC I think I understand this.  It's not
> trivial, but not super-complex either...  it would really be nice to add
> it to the protocol already in 1.6.
>
> Paolo
>

I will submit this as a brand new patch series. I'm working on it right now.

- Michael