On Thu, 16 Nov 2017 08:09:04 +0100 Björn Töpel <bjorn.to...@gmail.com> wrote:
> Ideally, it would be best not having to introduce yet another xmit > ndo. I believe ndo_xdp_xmit/ndo_xdp_flush would be the best fit, but > we need to extend it with a destructor callback and potentially some > kind of DMA trait. Why DMA? For zerocopy, we know the working set of > packet buffers, so they are DMA mapped up front, whereas ndo_xdp_xmit > does yet another DMA mapping. Paying for the DMA mapping in the > fast-path is something we'd like to avoid. I like your idea of reusing ndo_xdp_xmit/ndo_xdp_flush. At NetConf I think we agreed that the ndo_xdp_xmit API likely need to change. See[1] slide 11. Andy Gospodarek and Michael Chan wanted to look into the needed API changes (Cc'ed) thus, lets keep them in the loop. I also appreciate that you are thinking about avoiding the DMA-mapping at TX. It would be a welcomed optimization. [1] http://people.netfilter.org/hawk/presentations/NetConf2017_Seoul/XDP_devel_update_NetConf2017_Seoul.pdf -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer
