Re: [Qemu-devel] [PATCH COLO-Frame v10 09/38] COLO: Implement colo checkpoint protocol

[zhanghailiang <zhang.zhanghailiang@huawei.com>]

On 2015/11/14 0:46, Eric Blake wrote:
> On 11/03/2015 04:56 AM, zhanghailiang wrote:
>> We need communications protocol of user-defined to control the checkpoint
>> process.
>>
>> The new checkpoint request is started by Primary VM, and the interactive process
>> like below:
>> Checkpoint synchronizing points,
>>
>>                         Primary                         Secondary
>> 'checkpoint-request'   @ ----------------------------->
>>                                                         Suspend (In hybrid mode)
>> 'checkpoint-reply'     <------------------------------ @
>>                         Suspend&Save state
>> 'vmstate-send'         @ ----------------------------->
>>                         Send state                      Receive state
>> 'vmstate-received'     <------------------------------ @
>>                         Release packets                 Load state
>> 'vmstate-load'         <------------------------------ @
>>                         Resume                          Resume (In hybrid mode)
>>
>>                         Start Comparing (In hybrid mode)
>> NOTE:
>>   1) '@' who sends the message
>>   2) Every sync-point is synchronized by two sides with only
>>      one handshake(single direction) for low-latency.
>>      If more strict synchronization is required, a opposite direction
>>      sync-point should be added.
>>   3) Since sync-points are single direction, the remote side may
>>      go forward a lot when this side just receives the sync-point.
>>   4) For now, we only support 'periodic' checkpoint, for which
>>     the Secondary VM is not running, later we will support 'hybrid' mode.
>>
>> Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
>> Signed-off-by: Li Zhijian <lizhijian@cn.fujitsu.com>
>> Signed-off-by: Gonglei <arei.gonglei@huawei.com>
>> Cc: Eric Blake <eblake@redhat.com>
>> ---
>> v10:
>> - Rename enum COLOCmd to COLOCommand (Eric's suggestion).
>> - Remove unused 'ram-steal'
>
> Interface review only:
>
>
>> +++ b/qapi-schema.json
>> @@ -702,6 +702,33 @@
>>               '*tls-port': 'int', '*cert-subject': 'str' } }
>>
>>   ##
>> +# @COLOCommand
>> +#
>> +# The colo command
>
> Still might be nice to spell out what COLO means here, but it's fairly
> obvious this will be related to anything else COLO, so I'm not too worried.
>

Hmm, i think the best way to solve the abbreviation problem is to give the full
name where it appears for the first time ;)

>> +#
>> +# @invalid: unknown command
>> +#
>> +# @checkpoint-ready: SVM is ready for checkpointing
>> +#
>> +# @checkpoint-request: PVM tells SVM to prepare for new checkpointing
>> +#
>> +# @checkpoint-reply: SVM gets PVM's checkpoint request
>> +#
>> +# @vmstate-send: VM's state will be sent by PVM.
>> +#
>> +# @vmstate-size: The total size of VMstate.
>> +#
>> +# @vmstate-received: VM's state has been received by SVM
>> +#
>> +# @vmstate-loaded: VM's state has been loaded by SVM
>> +#
>> +# Since: 2.5
>
> Will need a tweak to say 2.6.  Otherwise looks okay.
>

OK, i will update it. Thanks.

>> +##
>> +{ 'enum': 'COLOCommand',
>> +  'data': [ 'invalid', 'checkpoint-ready', 'checkpoint-request',
>> +            'checkpoint-reply', 'vmstate-send', 'vmstate-size',
>> +            'vmstate-received', 'vmstate-loaded' ] }
>> +
>
>