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

[zhanghailiang]

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 <address@hidden>
> > Signed-off-by: Li Zhijian <address@hidden>
> > Signed-off-by: Gonglei <address@hidden>
> > Cc: Eric Blake <address@hidden>
> > ---
> > 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' ] }
> > +