Re: [Qemu-devel] [RFC PATCH 03/12] migration: make qemu_savevm_state public.

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

* Frederic Konrad (fred.konrad@greensocs.com) wrote:
> On 21/03/2014 20:54, Dr. David Alan Gilbert wrote:
> >* fred.konrad@greensocs.com (fred.konrad@greensocs.com) wrote:
> >>From: KONRAD Frederic <fred.konrad@greensocs.com>
> >>
> >>This makes qemu_savevm_state public for reverse-execution.
> >It's interesting that you're doing this repetitive snapshot;
> >in some ways it's similar to Michael Hines's code for
> >Fault tolerance ( http://lists.gnu.org/archive/html/qemu-devel/2014-02/msg03042.html )
> >
> >Dave
> 
> Hi,
> 
> Thanks for the link I missed this.
> 
> Seems mc is using live migration and we just checkpoint the whole machine.
> 
> That might be a good improvment.

I doubt it directly; there's not that much difference between snapshot to file
and migrate to file (if you follow the paths they take basically the same route;
I think the only thing is that the snapshot mechanism allows you to save snapshots
into an existing qcow2 file).

However, I was more pointing out the overlap in problem - both of you needing
to take regular snapshots (at probably as quick a rate as you can manage)
but with different criteria for the lifetime and reason for restoration
of the snap.

Dave

> 
> Fred
> 
> >
> >>Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
> >>---
> >>  include/sysemu/sysemu.h | 1 +
> >>  savevm.c                | 2 +-
> >>  2 files changed, 2 insertions(+), 1 deletion(-)
> >>
> >>diff --git a/include/sysemu/sysemu.h b/include/sysemu/sysemu.h
> >>index 3915ce3..fe86615 100644
> >>--- a/include/sysemu/sysemu.h
> >>+++ b/include/sysemu/sysemu.h
> >>@@ -78,6 +78,7 @@ void do_info_snapshots(Monitor *mon, const QDict *qdict);
> >>  void qemu_announce_self(void);
> >>+int qemu_savevm_state(QEMUFile *f);
> >>  bool qemu_savevm_state_blocked(Error **errp);
> >>  void qemu_savevm_state_begin(QEMUFile *f,
> >>                               const MigrationParams *params);
> >>diff --git a/savevm.c b/savevm.c
> >>index d094fbb..e50b716 100644
> >>--- a/savevm.c
> >>+++ b/savevm.c
> >>@@ -635,7 +635,7 @@ void qemu_savevm_state_cancel(void)
> >>      }
> >>  }
> >>-static int qemu_savevm_state(QEMUFile *f)
> >>+int qemu_savevm_state(QEMUFile *f)
> >>  {
> >>      int ret;
> >>      MigrationParams params = {
> >>-- 
> >>1.8.1.4
> >>
> >>
> >--
> >Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
> >
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK