[Qemu-devel] Re: Live migration broken when under heavy IO

[Anthony Liguori]

Avi Kivity wrote:
> > Does anyone have a clever idea how to fix this without just waiting 
> > for all IO requests to complete?
>
> What's wrong with waiting for requests to complete?  It should take a 
> few tens of milliseconds.

An alternative would be to attempt to cancel the requests.  This incurs 
no non-deterministic latency.

The tricky bit is that this has to happen at the device layer because 
the opaques cannot be saved in a meaningful way.

> We could start throttling requests late in the live stage, but I don't 
> really see the point.
>
> Isn't virtio migration currently broken due to the qdev changes?


--
Regards,

Anthony Liguori