Re: [Qemu-devel] [RFC 10/29] migration: new property "x-postcopy-fast"

[Peter Xu]

On Mon, Jul 31, 2017 at 07:52:24PM +0100, Dr. David Alan Gilbert wrote:
> * Peter Xu (address@hidden) wrote:
> > This provides a way to start postcopy ASAP when migration starts. To do
> > this, we need both:
> > 
> >   -global migration.x-postcopy-ram=on \
> >   -global migration.x-postcopy-fast=on
> 
> Can you explain why this is necessary?  Both sides already know
> they're doing a postcopy recovery don't they?

What I wanted to do here is to provide a way to start postcopy at the
very beginning (actually it'll possibly start postcopy at the first
loop in migration_thread), instead of start postcopy until we trigger
it using "migrate_start_postcopy" command.

I used it for easier debugging (so I don't need to type
"migrate_start_postcopy" every time when I trigger postcopy
migration), meanwhile I think it can also be used when someone really
want to start postcopy from the very beginning.

Would such a new parameter makes sense?

-- 
Peter Xu