On Tue, 20 Sep 2016 17:01:39 -0700 Alexei Starovoitov <a...@fb.com> wrote:
> > - Provides a more structured environment that is extensible to new > > features while being mostly transparent to the drivers > > don't see that in these patches either. > Things like packet size change (that we're working on) still > has to be implemented for every driver. > Existing XDP_TX, XDP_DROP have to be implemented per driver as well. > > Also introduction of xdp.h breaks existing UAPI. > That's not acceptable either. This response piss me off!@@#$ We are the early stages of XDP development. Users cannot consider XDP a stable UAPI yet. I added a big fat warning to the docs here[1]. If you already consider this a stable API, then I will suggest that we disable XDP or rip the hole thing out again!!! Create a separate tree where we can cooperate on getting this right, before forcing this upstream. I have raise concern about this several times upstream, but the patches got applied anyway, because you Alexei, promised this was super extendable and we could still change the APIs later. Maybe you tricked me?! I've started to look at the details, and I'm not happy with the extensibility. And I'm also not happy with Brenden's response to my API concerns that this is just a "fire-and-forget" API. Most importantly, the XDP interface for feature or capabilities negotiation is missing. Documented here[2]. I strongly believe the two actions XDP_DROP and XDP_TX should have been express as two different capabilities, because XDP_TX requires more changes to the device driver than a simple drop like XDP_DROP. One can easily imagine (after the e1000 discussion) that an older driver only want to implement the XDP_DROP facility. The reason is that XDP_TX would requires changing too much driver code, which is a concern for an old stable and time-proven driver. Thus, the need for negotiating features is already a practical problem! [1] https://prototype-kernel.readthedocs.io/en/latest/networking/XDP/implementation/userspace_api.html Quote: "Warning: The userspace API specification should have to be defined properly before code was accepted upstream. Concerns have been raise about the current API upstream. Users should expect this first API attempt will need adjustments. This cannot be considered a stable API yet." [2] https://prototype-kernel.readthedocs.io/en/latest/networking/XDP/design/design.html#capabilities-negotiation -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat Author of http://www.iptv-analyzer.org LinkedIn: http://www.linkedin.com/in/brouer
