[Qemu-devel] [PATCH] migration: Fix rate limit

[Qemu-devel] [PATCH] migration: Fix rate limit

[Matthew Garrett]

The migration thread appears to want to allow writeout to occur at full
speed rather than being rate limited during completion of state saving,
but sets the limit to INT_MAX when xfer_limit is INT64_MAX. This causes
problems if there's more than 2GB of state left to save at this point. It
probably ought to just be INT64_MAX instead.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
---
 migration.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration.c b/migration.c
index 2b1ab20..ff00bfb 100644
--- a/migration.c
+++ b/migration.c
@@ -583,7 +583,7 @@ static void *migration_thread(void *opaque)
 
                 ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
                 if (ret >= 0) {
-                    qemu_file_set_rate_limit(s->file, INT_MAX);
+                    qemu_file_set_rate_limit(s->file, INT64_MAX);
                     qemu_savevm_state_complete(s->file);
                 }
                 qemu_mutex_unlock_iothread();
-- 
1.8.4.2

Re: [Qemu-devel] [PATCH] migration: Fix rate limit

[Matthew Garrett]

Any feedback on this?

On Mon, Nov 25, 2013 at 02:42:43PM -0500, Matthew Garrett wrote:
> The migration thread appears to want to allow writeout to occur at full
> speed rather than being rate limited during completion of state saving,
> but sets the limit to INT_MAX when xfer_limit is INT64_MAX. This causes
> problems if there's more than 2GB of state left to save at this point. It
> probably ought to just be INT64_MAX instead.
> 
> Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
> ---
>  migration.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/migration.c b/migration.c
> index 2b1ab20..ff00bfb 100644
> --- a/migration.c
> +++ b/migration.c
> @@ -583,7 +583,7 @@ static void *migration_thread(void *opaque)
>  
>                  ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
>                  if (ret >= 0) {
> -                    qemu_file_set_rate_limit(s->file, INT_MAX);
> +                    qemu_file_set_rate_limit(s->file, INT64_MAX);
>                      qemu_savevm_state_complete(s->file);
>                  }
>                  qemu_mutex_unlock_iothread();
> -- 
> 1.8.4.2
> 
> 
> 
-- 
Matthew Garrett | mjg59@srcf.ucam.org

Re: [Qemu-devel] [PATCH] migration: Fix rate limit

[Paolo Bonzini]

> On Mon, Nov 25, 2013 at 02:42:43PM -0500, Matthew Garrett wrote:
> > The migration thread appears to want to allow writeout to occur at full
> > speed rather than being rate limited during completion of state saving,
> > but sets the limit to INT_MAX when xfer_limit is INT64_MAX. This causes
> > problems if there's more than 2GB of state left to save at this point. It
> > probably ought to just be INT64_MAX instead.
> > 
> > Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
> > ---
> >  migration.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/migration.c b/migration.c
> > index 2b1ab20..ff00bfb 100644
> > --- a/migration.c
> > +++ b/migration.c
> > @@ -583,7 +583,7 @@ static void *migration_thread(void *opaque)
> >  
> >                  ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
> >                  if (ret >= 0) {
> > -                    qemu_file_set_rate_limit(s->file, INT_MAX);
> > +                    qemu_file_set_rate_limit(s->file, INT64_MAX);
> >                      qemu_savevm_state_complete(s->file);
> >                  }
> >                  qemu_mutex_unlock_iothread();
> > --
> > 1.8.4.2


I didn't see this,

Cc: qemu-stable@nongnu.org
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>