From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38076C4320A for ; Fri, 30 Jul 2021 23:00:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2283D601FC for ; Fri, 30 Jul 2021 23:00:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234029AbhG3XA2 (ORCPT ); Fri, 30 Jul 2021 19:00:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233584AbhG3XA1 (ORCPT ); Fri, 30 Jul 2021 19:00:27 -0400 Received: from mail-yb1-xb35.google.com (mail-yb1-xb35.google.com [IPv6:2607:f8b0:4864:20::b35]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F3BF8C0613D3; Fri, 30 Jul 2021 16:00:20 -0700 (PDT) Received: by mail-yb1-xb35.google.com with SMTP id x192so18588685ybe.0; Fri, 30 Jul 2021 16:00:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=G03xh2kAEbzlimx7cJbVe+bLXkoyZqrXclrus0q2F4E=; b=MIaoNMVH6LJl09DjX0vC5H8SNneLdqQcfNsc80BvzBlZkKoC2DtrvschrDusLA0gfQ qkN9pjKZYagMu/Eyzfcl8IaG/Y9mkpeblkfRi4S0alFUFD3cmEC5a4tJhz3N2kn8Bz2V sGHgkvXGTUDNqCbvWENL9d7n1DYBW9PsBi18cMnnb+1qGUBLYHlFK6ixCEENvk524gRP jzcVgdabhqC6aONuKuS9I6hsIJxnTFuwoai2RyP95bfFkwWeNPeArbYeySwTswi+AHkt /FZkKF1zTns6MS7b8xiaSYHlwbtCivL4Y+pDPawp4dGkcBzInvhVbUeQRYkA7UOezb6l BwwA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=G03xh2kAEbzlimx7cJbVe+bLXkoyZqrXclrus0q2F4E=; b=hcm8GKM5jie2qfHSQMJNqTmiRS1Uqo5USmLw9Bm4qz0xyBv8qrKGpkgMm6zVIdFSJz RMr11ObmvrU2ca5Cert005UBN52XEejjm2UzXO3K9pTy8zaZ3GgM6SytRhkS1lCG+fCv jgbBFJI1Lr8AGnSgsL/DJo1wIdm8f5G+5gRxj3EIziMcLFWqy23liTecaIJKdemDo3Th cpAEeyORhk/gq6e1AfF3rEKB7frgbMDU2uh68txmj5zdqd14+YSriCp7KwtP2jeiFVVs KzrhN6UAT1W7aNn0OHW3254yb0CfzL6uTyCCQQ4fxkydWsHhkFNGAHVx2o17WAFaBhR7 tLOQ== X-Gm-Message-State: AOAM530vJLPEvKAYmwvpedYgRahfq+boJfy1aSUcchOREXscArhgi5B3 aKWbXpSCZAmTxdWjlnPSyEZuXBILIhpUJQ8qPZM= X-Google-Smtp-Source: ABdhPJzR3hu9wEK1ei/jdw+SsQqgvL2GQEp6u/NefeZQmwQMIWqBVbK/5v3hEAmdh4wIl57oNGwI3op7jJsExO8uYf0= X-Received: by 2002:a25:9942:: with SMTP id n2mr6411359ybo.230.1627686020211; Fri, 30 Jul 2021 16:00:20 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Andrii Nakryiko Date: Fri, 30 Jul 2021 16:00:08 -0700 Message-ID: Subject: Re: [PATCH v10 bpf-next 00/18] mvneta: introduce XDP multi-buffer support To: Lorenzo Bianconi Cc: Lorenzo Bianconi , bpf , Networking , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Shay Agroskin , john fastabend , David Ahern , Jesper Dangaard Brouer , Eelco Chaudron , Jason Wang , Alexander Duyck , Saeed Mahameed , Maciej Fijalkowski , Magnus Karlsson , tirthendu.sarkar@intel.com, =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hyZ2Vuc2Vu?= , Lorenzo Bianconi Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Wed, Jul 28, 2021 at 2:47 AM Lorenzo Bianconi wrote: > > > From: Lorenzo Bianconi > > > > This series introduce XDP multi-buffer support. The mvneta driver is > > the first to support these new "non-linear" xdp_{buff,frame}. Reviewers > > please focus on how these new types of xdp_{buff,frame} packets > > traverse the different layers and the layout design. It is on purpose > > that BPF-helpers are kept simple, as we don't want to expose the > > internal layout to allow later changes. > > I sent the cover-letter. Sorry for the noise. > > Regards, > Lorenzo > > > > > The main idea for the new multi-buffer layout is to reuse the same > > layout used for non-linear SKB. This rely on the "skb_shared_info" > > struct at the end of the first buffer to link together subsequent > > buffers. Keeping the layout compatible with SKBs is also done to ease > > and speedup creating a SKB from an xdp_{buff,frame}. > > Converting xdp_frame to SKB and deliver it to the network stack is show= n > > in patch 05/18 (e.g. cpumaps). > > > > A multi-buffer bit (mb) has been introduced in the flags field of xdp_{= buff,frame} > > structure to notify the bpf/network layer if this is a xdp multi-buffer= frame > > (mb =3D 1) or not (mb =3D 0). > > The mb bit will be set by a xdp multi-buffer capable driver only for > > non-linear frames maintaining the capability to receive linear frames > > without any extra cost since the skb_shared_info structure at the end > > of the first buffer will be initialized only if mb is set. > > Moreover the flags field in xdp_{buff,frame} will be reused even for > > xdp rx csum offloading in future series. > > > > Typical use cases for this series are: > > - Jumbo-frames > > - Packet header split (please see Google=E2=80=99s use-case @ NetDevCon= f 0x14, [0]) > > - TSO > > > > The two following ebpf helpers (and related selftests) has been introdu= ced: > > - bpf_xdp_adjust_data: > > Move xdp_md->data and xdp_md->data_end pointers in subsequent fragmen= ts > > according to the offset provided by the ebpf program. This helper can= be > > used to read/write values in frame payload. > > - bpf_xdp_get_buff_len: > > Return the total frame size (linear + paged parts) > > > > bpf_xdp_adjust_tail and bpf_xdp_copy helpers have been modified to take= into > > account xdp multi-buff frames. > > Seems like your changes are breaking selftests in no-alu32 mode ([0]). Please take a look. [0] https://github.com/kernel-patches/bpf/runs/3197530080?check_suite_foc= us=3Dtrue > > More info about the main idea behind this approach can be found here [1= ][2]. > > > > Changes since v9: > > - introduce bpf_xdp_adjust_data helper and related selftest > > - add xdp_frags_size and xdp_frags_tsize fields in skb_shared_info > > - introduce xdp_update_skb_shared_info utility routine in ordere to not= reset > > frags array in skb_shared_info converting from a xdp_buff/xdp_frame t= o a skb > > - simplify bpf_xdp_copy routine > > > > Changes since v8: > > - add proper dma unmapping if XDP_TX fails on mvneta for a xdp multi-bu= ff > > - switch back to skb_shared_info implementation from previous xdp_share= d_info > > one > > - avoid using a bietfield in xdp_buff/xdp_frame since it introduces per= formance > > regressions. Tested now on 10G NIC (ixgbe) to verify there are no per= formance > > penalties for regular codebase > > - add bpf_xdp_get_buff_len helper and remove frame_length field in xdp = ctx > > - add data_len field in skb_shared_info struct > > - introduce XDP_FLAGS_FRAGS_PF_MEMALLOC flag > > > > Changes since v7: > > - rebase on top of bpf-next > > - fix sparse warnings > > - improve comments for frame_length in include/net/xdp.h > > > > Changes since v6: > > - the main difference respect to previous versions is the new approach = proposed > > by Eelco to pass full length of the packet to eBPF layer in XDP conte= xt > > - reintroduce multi-buff support to eBPF kself-tests > > - reintroduce multi-buff support to bpf_xdp_adjust_tail helper > > - introduce multi-buffer support to bpf_xdp_copy helper > > - rebase on top of bpf-next > > > > Changes since v5: > > - rebase on top of bpf-next > > - initialize mb bit in xdp_init_buff() and drop per-driver initializati= on > > - drop xdp->mb initialization in xdp_convert_zc_to_xdp_frame() > > - postpone introduction of frame_length field in XDP ctx to another ser= ies > > - minor changes > > > > Changes since v4: > > - rebase ontop of bpf-next > > - introduce xdp_shared_info to build xdp multi-buff instead of using th= e > > skb_shared_info struct > > - introduce frame_length in xdp ctx > > - drop previous bpf helpers > > - fix bpf_xdp_adjust_tail for xdp multi-buff > > - introduce xdp multi-buff self-tests for bpf_xdp_adjust_tail > > - fix xdp_return_frame_bulk for xdp multi-buff > > > > Changes since v3: > > - rebase ontop of bpf-next > > - add patch 10/13 to copy back paged data from a xdp multi-buff frame t= o > > userspace buffer for xdp multi-buff selftests > > > > Changes since v2: > > - add throughput measurements > > - drop bpf_xdp_adjust_mb_header bpf helper > > - introduce selftest for xdp multibuffer > > - addressed comments on bpf_xdp_get_frags_count > > - introduce xdp multi-buff support to cpumaps > > > > Changes since v1: > > - Fix use-after-free in xdp_return_{buff/frame} > > - Introduce bpf helpers > > - Introduce xdp_mb sample program > > - access skb_shared_info->nr_frags only on the last fragment > > > > Changes since RFC: > > - squash multi-buffer bit initialization in a single patch > > - add mvneta non-linear XDP buff support for tx side > > > > [0] https://netdevconf.info/0x14/session.html?talk-the-path-to-tcp-4k-m= tu-and-rx-zerocopy > > [1] https://github.com/xdp-project/xdp-project/blob/master/areas/core/x= dp-multi-buffer01-design.org > > [2] https://netdevconf.info/0x14/session.html?tutorial-add-XDP-support-= to-a-NIC-driver (XDPmulti-buffers section) > > > > Eelco Chaudron (3): > > bpf: add multi-buff support to the bpf_xdp_adjust_tail() API > > bpf: add multi-buffer support to xdp copy helpers > > bpf: update xdp_adjust_tail selftest to include multi-buffer > > > > Lorenzo Bianconi (15): > > net: skbuff: add size metadata to skb_shared_info for xdp > > xdp: introduce flags field in xdp_buff/xdp_frame > > net: mvneta: update mb bit before passing the xdp buffer to eBPF laye= r > > net: mvneta: simplify mvneta_swbm_add_rx_fragment management > > net: xdp: add xdp_update_skb_shared_info utility routine > > net: marvell: rely on xdp_update_skb_shared_info utility routine > > xdp: add multi-buff support to xdp_return_{buff/frame} > > net: mvneta: add multi buffer support to XDP_TX > > net: mvneta: enable jumbo frames for XDP > > bpf: introduce bpf_xdp_get_buff_len helper > > bpf: move user_size out of bpf_test_init > > bpf: introduce multibuff support to bpf_prog_test_run_xdp() > > bpf: test_run: add xdp_shared_info pointer in bpf_test_finish > > signature > > net: xdp: introduce bpf_xdp_adjust_data helper > > bpf: add bpf_xdp_adjust_data selftest > > > > drivers/net/ethernet/marvell/mvneta.c | 213 ++++++++++-------- > > include/linux/skbuff.h | 6 +- > > include/net/xdp.h | 95 +++++++- > > include/uapi/linux/bpf.h | 38 ++++ > > kernel/trace/bpf_trace.c | 3 + > > net/bpf/test_run.c | 117 ++++++++-- > > net/core/filter.c | 210 ++++++++++++++++- > > net/core/xdp.c | 76 ++++++- > > tools/include/uapi/linux/bpf.h | 38 ++++ > > .../bpf/prog_tests/xdp_adjust_data.c | 55 +++++ > > .../bpf/prog_tests/xdp_adjust_tail.c | 118 ++++++++++ > > .../selftests/bpf/prog_tests/xdp_bpf2bpf.c | 151 +++++++++---- > > .../bpf/progs/test_xdp_adjust_tail_grow.c | 10 +- > > .../bpf/progs/test_xdp_adjust_tail_shrink.c | 32 ++- > > .../selftests/bpf/progs/test_xdp_bpf2bpf.c | 2 +- > > .../bpf/progs/test_xdp_update_frags.c | 49 ++++ > > 16 files changed, 1044 insertions(+), 169 deletions(-) > > create mode 100644 tools/testing/selftests/bpf/prog_tests/xdp_adjust_d= ata.c > > create mode 100644 tools/testing/selftests/bpf/progs/test_xdp_update_f= rags.c > > > > -- > > 2.31.1 > >