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[130.25.105.72]) by smtp.gmail.com with ESMTPSA id og26sm8825532ejc.52.2021.06.29.12.18.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 29 Jun 2021 12:18:12 -0700 (PDT) Date: Tue, 29 Jun 2021 21:18:09 +0200 From: Lorenzo Bianconi To: Jesper Dangaard Brouer Cc: Jakub Kicinski , Alexander Duyck , Lorenzo Bianconi , bpf , Netdev , David Miller , Alexei Starovoitov , Daniel Borkmann , shayagr@amazon.com, "Jubran, Samih" , John Fastabend , David Ahern , Jesper Dangaard Brouer , Eelco Chaudron , Jason Wang , Saeed Mahameed , Maciej Fijalkowski , "Karlsson, Magnus" , Tirthendu Subject: Re: [PATCH v9 bpf-next 01/14] net: skbuff: add data_len field to skb_shared_info Message-ID: References: <8ad0d38259a678fb42245368f974f1a5cf47d68d.1623674025.git.lorenzo@kernel.org> <20210629100852.56d995a6@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> <20210629113714.6d8e2445@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="6C7xQUoMCT1UaPk3" Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org --6C7xQUoMCT1UaPk3 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable >=20 > On 29/06/2021 20.37, Jakub Kicinski wrote: > > On Tue, 29 Jun 2021 11:18:38 -0700 Alexander Duyck wrote: > > > On Tue, Jun 29, 2021 at 10:08 AM Jakub Kicinski wro= te: > > > > > ack, I agree. I will fix it in v10. > > > > Why is XDP mb incompatible with LRO? I thought that was one of the = use > > > > cases (mentioned by Willem IIRC). > > > XDP is meant to be a per packet operation with support for TX and > > > REDIRECT, and LRO isn't routable. So we could put together a large LRO > > > frame but we wouldn't be able to break it apart again. If we allow > > > that then we are going to need a ton more exception handling added to > > > the XDP paths. > > >=20 > > > As far as GSO it would require setting many more fields in order to > > > actually make it offloadable by any hardware. > > It would require more work, but TSO seems to be explicitly stated > > as what the series builds towards (in the cover letter). It's fine > > to make choices we'd need to redo later, I guess, I'm just trying > > to understand the why. >=20 > This is also my understanding that LRO and TSO is what this patchset is > working towards. >=20 > Sorry, I don't agree or understand this requested change. >=20 >=20 My understanding here is to use gso_size to store paged length of the xdp multi-buffer. When converting the xdp_frame to a skb we will need to overwrite it to support gro/lro. Is my understanding correct? Regards, Lorenzo --6C7xQUoMCT1UaPk3 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQTquNwa3Txd3rGGn7Y6cBh0uS2trAUCYNtx7wAKCRA6cBh0uS2t rH/UAPwNEZ4DDX3WqxSWMTWy1OOH6l9pB0wd1UVwORqh4iBoUQEAnkjE2TT5F3KA AOiKWMPB6kUrags5y7wvAi82DQNFbQ8= =3YJx -----END PGP SIGNATURE----- --6C7xQUoMCT1UaPk3--