On Wed, Dec 19, 2018 at 10:34:28AM +0100, Björn Töpel wrote: > > On 2018-12-19 00:04, Alexei Starovoitov wrote: > > On Mon, Dec 17, 2018 at 04:30:05PM +0100, Björn Töpel wrote: > > > > > > > > Instead of introducing the XDP_ATTACH option to the bind call, can we > > > > just make this association between rx queue id and xsk every single > > > > time we bind? Then it is up to the user via the XDP program if he/she > > > > wants to use this by calling xsk_redirect. No new option needed. > > > > > > > > > > Nice! Then it would simply be a matter of adding the helper. Much better > > > than extending the uapi. Thank you for pointing this out! > > > > Magnus's by-default association approach sounds good to me. > > I'm missing though why extra bpf helper is needed. > > This soft-bind rx queue with xsk at the time > > of normal bind() should work as-is and no program necessary. > > Hmm, an XDP program has always been required. It's just whether the > program needs an XSKMAP or not. The XDP_ATTACH can be seens as "use an > internal map" -- and the mechanism to redirect using that map is via the > bpf_xsk_redirect helper. What Magnus proposed was populating the builtin > map unconditionally, and therefore removing the need for the XDP_ATTACH > option.
well, I'm actually proposing to make af_xdp program optional if hard coded queue->xsk mapping gives extra performance.
