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Re: [Qemu-devel] [PATCH v4 22/47] QEMU_VM_CMD_PACKAGED: Send a packaged
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH v4 22/47] QEMU_VM_CMD_PACKAGED: Send a packaged chunk of migration stream |
Date: |
Tue, 4 Nov 2014 10:19:15 +0000 |
User-agent: |
Mutt/1.5.23 (2014-03-12) |
* David Gibson (address@hidden) wrote:
> On Fri, Oct 03, 2014 at 06:47:28PM +0100, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > QEMU_VM_CMD_PACKAGED is a migration command that allows a chunk
> > of migration stream to be sent in one go, and be received by
> > a separate instance of the loadvm loop while not interacting
> > with the migration stream.
> >
> > This is used by postcopy to load device state (from the package)
> > while loading memory pages from the main stream.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
>
> Reviewed-by: David Gibson <address@hidden>
>
> Though one minor comment:
>
> [snip]
> > +/* We have a buffer of data to send; we don't want that all to be loaded
> > + * by the command itself, so the command contains just the length of the
> > + * extra buffer that we then send straight after it.
> > + * TODO: Must be a better way to organise that
>
> I'm not quite understanding what that comment's getting at.
We have these VM Commands; and they are a command type, and a length:
CMD_whatever
length: whatever
data for whatever
This comment is describing that, to make things easier for this code it's
ended up as:
CMD_PACKAGED
CMD length: 4 <--- i.e. just enough to hold the next 'length' field
package length
---------------
The package
Which is a little different, hence i thought it needed the comment.
Dave
>
> --
> David Gibson | I'll have my music baroque, and my code
> david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_
> _other_
> | _way_ _around_!
> http://www.ozlabs.org/~dgibson
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK