Re: [Qemu-block] [PATCH 11/17] migration: add is_active_iterate handler

[Vladimir Sementsov-Ogievskiy]

24.01.2017 12:48, Juan Quintela wrote:
> Vladimir Sementsov-Ogievskiy <address@hidden> wrote:
> > Only-postcopy savevm states (dirty-bitmap) don't need live iteration, so
> > to disable them and stop transporting empty sections there is a new
> > savevm handler.
> >
> > Signed-off-by: Vladimir Sementsov-Ogievskiy <address@hidden>
> > ---
> >   include/migration/vmstate.h | 1 +
> >   migration/savevm.c          | 5 +++++
> >   2 files changed, 6 insertions(+)
> >
> > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> > index dc656be..2c53d0b 100644
> > --- a/include/migration/vmstate.h
> > +++ b/include/migration/vmstate.h
> > @@ -47,6 +47,7 @@ typedef struct SaveVMHandlers {
> >       /* This runs both outside and inside the iothread lock.  */
> >       bool (*is_active)(void *opaque);
> >       bool (*has_postcopy)(void *opaque);
> > +    bool (*is_active_iterate)(void *opaque);
> >   
> >       /* This runs outside the iothread lock in the migration case, and
> >        * within the lock in the savevm case.  The callback had better only
> > diff --git a/migration/savevm.c b/migration/savevm.c
> > index c58b9f9..4eb1640 100644
> > --- a/migration/savevm.c
> > +++ b/migration/savevm.c
> > @@ -988,6 +988,11 @@ int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy)
> >                   continue;
> >               }
> >           }
> > +        if (se->ops && se->ops->is_active_iterate) {
> > +            if (!se->ops->is_active_iterate(se->opaque)) {
> > +                continue;
> > +            }
> > +        }
> >           /*
> >            * In the postcopy phase, any device that doesn't know how to
> >            * do postcopy should have saved it's state in the _complete
> Reviewed-by: Juan Quintela <address@hidden>
>
> I still don't see cleary why you can't "reuse" the is_active(), but
> well, it will have to add magic there, so ....

is_active_iterate=false blocks only qemu_savevm_state_iterate from 
handling the migration entity. Other qemu_savevm_state_* functions 
handle it, as is_active=true.

> BTW, in hindsight, this "is_active" functions are used mainly to check
> if the thing is "not active" O:-)


--
Best regards,
Vladimir