On Wed, 21 Sep 2016 11:50:06 -0700, Tom Herbert wrote: > On Wed, Sep 21, 2016 at 11:45 AM, Jakub Kicinski <kubak...@wp.pl> wrote: > > On Wed, 21 Sep 2016 10:39:40 -0700, Tom Herbert wrote: > >> On Wed, Sep 21, 2016 at 10:26 AM, Jakub Kicinski <kubak...@wp.pl> wrote: > >> > On Tue, 20 Sep 2016 17:01:39 -0700, Alexei Starovoitov wrote: > >> >> > - Reduces the amount of code and complexity needed in drivers to > >> >> > manage XDP > >> >> > >> >> hmm: > >> >> 534 insertions(+), 144 deletions(-) > >> >> looks like increase in complexity instead. > >> > > >> > and more to come to tie this with HW offloads. > >> > >> The amount of driver code did decrease with these patches: > >> > >> drivers/net/ethernet/mellanox/mlx4/en_netdev.c | 64 > >> ++++---------------------- > >> drivers/net/ethernet/mellanox/mlx4/en_rx.c | 25 ++++------ > >> drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 1 - > >> > >> Minimizing complexity being added to drivers for XDP is critical since > >> we basically asking every driver to replicate the function. This > >> property also should also apply to HW offloads, the more complexity we > >> can abstract out drivers into a common backend infrastructure the > >> better for supporting across different drivers. > > > > I'm in the middle of writing/testing XDP support for the Netronome's > > driver and generic infra is very much appreciated ;) In my experience > > the 50 lines of code which are required for assigning the programs and > > freeing them aren't really a big deal, though. > > > > 50 lines in one driver is not a big deal, 50 lines in a hundred > drivers is! I learned this lesson in BQL which was well abstracted out > to be minimally invasive but we still saw many issues because of the > pecularities of different drivers.
Agreed, I just meant to say that splitting rings and rewritting RX path to behave differently for XDP vs non-XDP case is way more brain consuming than a bit of boilerplate code so if anyone could solve those two it would be much appreciated :) My main point was what I wrote below, though. > > Let's also separate putting xdp_prog in netdevice/napi_struct from the > > generic hook infra. All the simplifications to the driver AFAICS come > > from the former. If everyone is fine with growing napi_struct we can do > > that but IMHO this is not an argument for the generic infra :)
