Re: [Qemu-devel] Live migration sequence

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Pavel Fedin (p.fedin@samsung.com) wrote:
>  Hello!
> 
> > Some thoughts:
> >   a) There is a migration state notifier list - see add_migration_state_change_notifier (spice
> > calls it)
> >      - but I don't think it's called in the right places for your needs;  we
> >      could add some more places that gets called.
> 
>  I am now trying to add one more state, something like MIGRATION_STATUS_FINISHING. It would mean that CPUs are stopped.
>  Can you explain me migration code a bit? Where is iteration loop, and where are CPUs stopped? I am looking at migration.c but
> cannot say that i understand some good portion of it. :)

The outgoing side of migration comes into migrate_fd_connect which does
all the setup and then starts 'migration_thread'.  The big while loop in there does
most of the work, and on each loop normally ends up calling either
   qemu_savevm_state_iterate
or
  migration_completion

migration_completion calls vm_stop_force_state to stop the CPU,
and then qemu_savevm_state_complete to save all the remaining devices
out.

Dave


> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK