Re: [Qemu-devel] [PATCH v4 45/47] Start up a postcopy/listener thread ready for incoming page data

[David Gibson]

On Wed, Nov 19, 2014 at 07:40:20PM +0000, Dr. David Alan Gilbert wrote:
> * David Gibson (address@hidden) wrote:
> > On Fri, Oct 03, 2014 at 06:47:51PM +0100, Dr. David Alan Gilbert (git) 
> > wrote:
> > > From: "Dr. David Alan Gilbert" <address@hidden>
> > > 
> > > The loading of a device state (during postcopy) may access guest
> > > memory that's still on the source machine and thus might need
> > > a page fill; split off a separate thread that handles the incoming
> > > page data so that the original incoming migration code can finish
> > > off the device data.
> > > 
> > > Signed-off-by: Dr. David Alan Gilbert <address@hidden>
> > > ---
> > >  include/migration/migration.h |  4 +++
> > >  migration.c                   |  6 +++++
> > >  savevm.c                      | 62 
> > > +++++++++++++++++++++++++++++++++++++++++--
> > >  3 files changed, 70 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/include/migration/migration.h b/include/migration/migration.h
> > > index 00255b8..69e776c 100644
> > > --- a/include/migration/migration.h
> > > +++ b/include/migration/migration.h
> > > @@ -92,6 +92,10 @@ struct MigrationIncomingState {
> > >      QemuThread     fault_thread;
> > >      QemuSemaphore  fault_thread_sem;
> > >  
> > > +    bool           have_listen_thread;
> > 
> > AFAICT have_listen_thread is never set to a value other than 'true',
> > so there doesn't see much point to it.
> 
> It's tested by qemu_loadvm_state to avoid doing cleaning stuff up as it exits,
> since the listen thread is still using it.

Right, but I couldn't see under what circumstances it would ever be
false at the test false in qemu_loadvm_state().

-- 
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

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