Re: [PATCH net-next] virtio-net: invoke zerocopy callback on xmit path if no tx napi

On Tue, Aug 29, 2017 at 03:53:08PM -0400, Willem de Bruijn wrote:

On Tue, Aug 29, 2017 at 3:42 PM, Michael S. Tsirkin [off-list ref] wrote:

quoted

On Tue, Aug 29, 2017 at 03:35:38PM -0400, Willem de Bruijn wrote:

quoted

By the way, I have had an unrelated patch outstanding for a while
to have virtio-net support the VIRTIO_CONFIG_S_NEEDS_RESET
command. Will send that as RFC.

Oh nice.

Great :)

quoted

One needs to be careful about locking there which is why
no devices support that yet.

I originally wrote it based on the virtnet_reset function introduced
for xdp. Calling this from virtnet_config_changed_work is non trivial,
as virtnet_freeze_down waits until no config worker is running.

Otherwise, I could not find any constraints on when freeze may be
called, and it largely follows the same path. I hope I didn't miss anything.

The issue is that on freeze processes are not running so we
generally know no new packets will arrive (might be wrong
for bridging, then it's a bug). On device error you must
prevent new skbs from coming in, etc.

-- 
MST