Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop

[Paolo Bonzini]

On 22/03/2016 10:07, Cornelia Huck wrote:
> So far, we had the best results with my refactoring + the mutex/bh
> change. Two problems:
> 
> - We don't really understand yet why my refactoring helps, but passing
> the assign value is a good canditate (and it's agreed that this fixes a
> bug, I think.)
> - There's some problem with the bh, if I understood Stefan correctly.

They can be fixed with just an extra object_ref/object_unref.

I didn't understand that Tu Bo also needed the BH fix, and with that
information it makes sense.  Passing the assign value ensures that
ioeventfd remains always assigned.  With the CPU threads out of the
picture, the BH becomes enough to make everything thread-safe.

Paolo