Re: NetBSD/xen goes off the network - reproduceable

[Brian Marcotte <marcotte%panix.com@localhost>]

> I found the problem: [bpf panic]

I'm no longer getting a panic.

> I also fixed the xennet_rx_free_req() logic to not wait for the
> ring to be completely empty to start filling it. 4/5 of the ring size
> looks a good compromise (doing it too often for a low number of buffers
> increases significantly the CPU usage).

In fact, without that, I would find that the dom0 would stop sending
packets to the domU about every minute or so. Having the domU send a
packet would unstick things. The packets were held somewhere and not
lost.

This is something I've seen in 5.1 as well, but only rarely and only
when a system was just sitting idle for long periods of time.

I found that switching to this code fixes that problem:

> +#if 0
> +     RING_PUSH_REQUESTS_AND_CHECK_NOTIFY(&sc->sc_rx_ring, notify);
> +     if (notify)
> +             hypervisor_notify_via_evtchn(sc->sc_evtchn);
> +#endif

In fact, I used to run with that code in place when I was running 5.0.

--
- Brian