Re: [RFC PATCH 2/2] virtio-balloon: add stats push mode

[Gregory Price <gourry@gourry.net>]

On Tue, Jun 16, 2026 at 04:32:46PM +0200, David Hildenbrand (Arm) wrote:
> On 6/16/26 15:57, Gregory Price wrote:
> > 
> > Definitely an RFC here because I'm not sure if I was missing something
> > that might help me solve the problem.
> 
> Well, in QEMU we just run a timer internally that does the polling.
> 
> Then, upper layers in the stack can ask QEMU for the latest stats.
> 
> There, you just get the stats along with a "last-update" timestamp.
>

That makes sense, although don't you just push the blocking operation
into yet another thread on the host?

Assuming it's not cancel-able, there's a blocked thread there you have
to reap.  Vs the guest being unresponsive and not sending updates, you
just reap the whole guest or take some other corrective action.

I suppose to the orchestrator reaping QEMU and reaping the guest looks
the same.  The difference is just where the thread lives, hmmmm

I'll make a note to inspect QEMU's solution to see if that's handled
or if it would be subject to the same issue.

Thanks!
~Gregory