From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jakub Kicinski Subject: Re: [PATCH RFC 1/3] xdp: Infrastructure to generalize XDP Date: Wed, 21 Sep 2016 19:45:48 +0100 Message-ID: <20160921194548.33b85cb3@jkicinski-Precision-T1700> References: <1474408824-418864-1-git-send-email-tom@herbertland.com> <1474408824-418864-2-git-send-email-tom@herbertland.com> <57E1CDE3.5030404@fb.com> <20160921182657.67681e67@jkicinski-Precision-T1700> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: Alexei Starovoitov , "David S. Miller" , Linux Kernel Network Developers , Kernel Team , Tariq Toukan , Brenden Blanco , Alexei Starovoitov , Eric Dumazet , Jesper Dangaard Brouer To: Tom Herbert Return-path: Received: from mx4.wp.pl ([212.77.101.12]:56529 "EHLO mx4.wp.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932941AbcIUSqJ (ORCPT ); Wed, 21 Sep 2016 14:46:09 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: On Wed, 21 Sep 2016 10:39:40 -0700, Tom Herbert wrote: > On Wed, Sep 21, 2016 at 10:26 AM, Jakub Kicinski 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. 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 :)