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Re: [Qemu-devel] [PATCH f0r 2.11] runstate/migrate: Two more transitions
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH f0r 2.11] runstate/migrate: Two more transitions |
Date: |
Mon, 7 Aug 2017 13:25:29 +0100 |
User-agent: |
Mutt/1.8.3 (2017-05-23) |
* Peter Xu (address@hidden) wrote:
> On Fri, Aug 04, 2017 at 06:50:11PM +0100, Dr. David Alan Gilbert (git) wrote:
> > From: "Dr. David Alan Gilbert" <address@hidden>
> >
> > There's a race if someone does a 'stop' near the end of migrate;
> > the migration process goes through two runstates:
> > 'finish migrate'
> > 'postmigrate'
> >
> > If the user issues a 'stop' between the two we end up with invalid
> > state transitions.
> > Add the transitions as valid.
> >
> > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > ---
> > vl.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/vl.c b/vl.c
> > index 99fcfa0442..bacb03f49d 100644
> > --- a/vl.c
> > +++ b/vl.c
> > @@ -621,6 +621,7 @@ static const RunStateTransition
> > runstate_transitions_def[] = {
> >
> > { RUN_STATE_PAUSED, RUN_STATE_RUNNING },
> > { RUN_STATE_PAUSED, RUN_STATE_FINISH_MIGRATE },
> > + { RUN_STATE_PAUSED, RUN_STATE_POSTMIGRATE },
> > { RUN_STATE_PAUSED, RUN_STATE_PRELAUNCH },
> > { RUN_STATE_PAUSED, RUN_STATE_COLO},
> >
> > @@ -633,6 +634,7 @@ static const RunStateTransition
> > runstate_transitions_def[] = {
> > { RUN_STATE_PRELAUNCH, RUN_STATE_INMIGRATE },
> >
> > { RUN_STATE_FINISH_MIGRATE, RUN_STATE_RUNNING },
> > + { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PAUSED },
> > { RUN_STATE_FINISH_MIGRATE, RUN_STATE_POSTMIGRATE },
> > { RUN_STATE_FINISH_MIGRATE, RUN_STATE_PRELAUNCH },
> > { RUN_STATE_FINISH_MIGRATE, RUN_STATE_COLO},
>
> Do we need this as well?
>
> { RUN_STATE_POSTMIGRATE, RUN_STATE_PAUSED },
Apparently not:
(qemu) migrate "exec:cat > /dev/null"
(qemu) infomigrate
unknown command: 'infomigrate'
(qemu) info status
VM status: paused (postmigrate)
(qemu) stop
(qemu) info status
VM status: paused (postmigrate)
(qemu)
so doing a stop at that point doesn't seem to cause any problem.
Dave
> --
> Peter Xu
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK