Re: [PATCH v1 00/13] Multifd 🔀 device state transfer support with VFIO consumer

[Peter Xu <peterx@redhat.com>]

On Thu, Jun 27, 2024 at 11:14:28AM +0200, Maciej S. Szmigiero wrote:
> Having RAM sent in parallel with non-iterables would make sense to me,
> but I am not 100% sure this is a safe thing to do - after all, currently
> non-iterables can rely on the whole RAM being already transferred.

And I forgot to comment on this one.. but that's a good point.

I think we need further investigation indeed on this one.  Some devices may
need special dependency like what you said either on memory fully loaded,
or something else like BQL, so at least concurrent load() won't work for
the latter.  What I was hoping is that we can start to collect some
time-consuming objects into async-model if they do not have such
dependencies.  The thing in my mind is still vcpus so far: that's what I
observed a major uncertainty on causing major downtimes as well.  I
remember vcpu only needs a loaded memory until KVM_RUN triggering loading
of CR3 so _maybe_ that'll be fine, but that needs some double checks.

Thanks,

-- 
Peter Xu