Maciej Fijalkowski wrote: > On Wed, Feb 28, 2024 at 07:05:56PM +0800, Yunjian Wang wrote: > > This patch set allows TUN to support the AF_XDP Tx zero-copy feature, > > which can significantly reduce CPU utilization for XDP programs. > > Why no Rx ZC support though? What will happen if I try rxdrop xdpsock > against tun with this patch? You clearly allow for that. This is AF_XDP receive zerocopy, right? The naming is always confusing with tun, but even though from a tun PoV this happens on ndo_start_xmit, it is the AF_XDP equivalent to tun_put_user. So the implementation is more like other device's Rx ZC. I would have preferred that name, but I think Jason asked for this and given tun's weird status, there is something bo said for either.
