On 13/04/2015 13:35, Dr. David Alan Gilbert wrote: >>>>>>> + qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER); >>>>>>> > >>> > > + *old_vm_running = runstate_is_running(); >>>>> > >> > >>>>> > >> > I think that needs some explanation. Why are you doing a wakeup on >>>>> > >> > the source host? >>> > > This matches the existing code in migration_thread for the end of >>> > > precopy; >>> > > Paolo's explanation of what it does is here: >>> > > https://lists.gnu.org/archive/html/qemu-devel/2014-08/msg04880.html >> > >> > The more I look at it, the more I'm convinced it's working by chance or >> > not working at all. > Do you mean in general or in the postcopy case?
In general. > > Here we probably need to do only the notifier_list_notify + > > qapi_event_send_wakeup. > > Do you mean a : > wakeup_reason = QEMU_WAKEUP_REASON_OTHER; > notifier_list_notify(&wakeup_notifiers, &wakeup_reason); > wakeup_reason = QEMU_WAKEUP_REASON_NONE; > qapi_event_send_wakeup(&error); > > which I guess would need wrapping up in vl.c Yes. > (It's not really clear to me what this stuff does even with > your previous explanation; if it's to do with migrating > something suspended-to-ram I guess a postcopy is possible > but it doesn't seem that sensible to use postcopy for a > machine with a CPU that isn't running). Yes, but management does not know in advance that the machine will suspend to RAM. It's basically a race. Paolo
