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=-16.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C6361C43461 for ; Thu, 3 Sep 2020 21:30:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A5E7D206CA for ; Thu, 3 Sep 2020 21:30:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728382AbgICVaR (ORCPT ); Thu, 3 Sep 2020 17:30:17 -0400 Received: from mga09.intel.com ([134.134.136.24]:63823 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726323AbgICVaQ (ORCPT ); Thu, 3 Sep 2020 17:30:16 -0400 IronPort-SDR: PTJ7MpH1Pl4nvlXrFc6JuBGPFqHubNk4ddWGspQIoRQMTflOzQEpXHBBiiW/WOC9bFHoIl6rXT tOIKuWvdT9XQ== X-IronPort-AV: E=McAfee;i="6000,8403,9733"; a="158641857" X-IronPort-AV: E=Sophos;i="5.76,387,1592895600"; d="scan'208";a="158641857" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Sep 2020 14:30:15 -0700 IronPort-SDR: Vch4X5rKnzPieib+o7yTwr1jyOyE4TSXRKJUwY/0UAPS1AXd9U+Txx+eeGne8Esu4CIdK2EaHm y1ufEPThJwYg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,387,1592895600"; d="scan'208";a="302368147" Received: from ranger.igk.intel.com ([10.102.21.164]) by orsmga006.jf.intel.com with ESMTP; 03 Sep 2020 14:30:10 -0700 Date: Thu, 3 Sep 2020 23:24:09 +0200 From: Maciej Fijalkowski To: Lorenzo Bianconi Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, davem@davemloft.net, lorenzo.bianconi@redhat.com, brouer@redhat.com, echaudro@redhat.com, sameehj@amazon.com, kuba@kernel.org, john.fastabend@gmail.com, daniel@iogearbox.net, ast@kernel.org, shayagr@amazon.com Subject: Re: [PATCH v2 net-next 7/9] bpf: helpers: add multibuffer support Message-ID: <20200903212409.GA14273@ranger.igk.intel.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Sep 03, 2020 at 10:58:51PM +0200, Lorenzo Bianconi wrote: > From: Sameeh Jubran > > The implementation is based on this [0] draft by Jesper D. Brouer. > > Provided two new helpers: > > * bpf_xdp_get_frag_count() > * bpf_xdp_get_frags_total_size() > > [0] xdp mb design - https://github.com/xdp-project/xdp-project/blob/master/areas/core/xdp-multi-buffer01-design.org > Signed-off-by: Sameeh Jubran > Signed-off-by: Lorenzo Bianconi > --- > include/uapi/linux/bpf.h | 14 ++++++++++++ > net/core/filter.c | 39 ++++++++++++++++++++++++++++++++++ > tools/include/uapi/linux/bpf.h | 14 ++++++++++++ > 3 files changed, 67 insertions(+) > > diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h > index c4a6d245619c..53db75095306 100644 > --- a/include/uapi/linux/bpf.h > +++ b/include/uapi/linux/bpf.h > @@ -3590,6 +3590,18 @@ union bpf_attr { > * > * Return > * 0 on success, or a negative error in case of failure. > + * > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md) > + * Description > + * Get the total number of frags for a given packet. > + * Return > + * The number of frags > + * > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md) > + * Description > + * Get the total size of frags for a given packet. > + * Return > + * The total size of frags for a given packet. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3742,6 +3754,8 @@ union bpf_attr { > FN(d_path), \ > FN(copy_from_user), \ > FN(xdp_adjust_mb_header), \ > + FN(xdp_get_frag_count), \ > + FN(xdp_get_frags_total_size), \ > /* */ > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > diff --git a/net/core/filter.c b/net/core/filter.c > index ae6b10cf062d..ba058fc16440 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c > @@ -3526,6 +3526,41 @@ static const struct bpf_func_proto bpf_xdp_adjust_mb_header_proto = { > .arg2_type = ARG_ANYTHING, > }; > > +BPF_CALL_1(bpf_xdp_get_frag_count, struct xdp_buff*, xdp) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + > + return xdp->mb ? sinfo->nr_frags : 0; > +} > + > +const struct bpf_func_proto bpf_xdp_get_frag_count_proto = { > + .func = bpf_xdp_get_frag_count, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_CTX, > +}; > + > +BPF_CALL_1(bpf_xdp_get_frags_total_size, struct xdp_buff*, xdp) > +{ > + struct skb_shared_info *sinfo = xdp_get_shared_info_from_buff(xdp); > + int nfrags, i; > + int size = 0; > + > + nfrags = xdp->mb ? sinfo->nr_frags : 0; > + > + for (i = 0; i < nfrags && i < MAX_SKB_FRAGS; i++) > + size += skb_frag_size(&sinfo->frags[i]); > + I only quickly jumped through series and IMHO this helper should be rewritten/optimized in a way that we bail out as early as possible if !xdp->mb as the rest of the code on that condition will do nothing and i'm not sure if compiler would optimize it. struct skb_shared_info *sinfo; int nfrags, i; int size = 0; if (!xdp->mb) return 0; sinfo = xdp_get_shared_info_from_buff(xdp); nfrags = min(sinfo->nr_frags, MAX_SKB_FRAGS); for (i = 0; i < nfrags; i++) size += skb_frag_size(&sinfo->frags[i]); return size; Thoughts? > + return size; > +} > + > +const struct bpf_func_proto bpf_xdp_get_frags_total_size_proto = { > + .func = bpf_xdp_get_frags_total_size, > + .gpl_only = false, > + .ret_type = RET_INTEGER, > + .arg1_type = ARG_PTR_TO_CTX, > +}; > + > BPF_CALL_2(bpf_xdp_adjust_tail, struct xdp_buff *, xdp, int, offset) > { > void *data_hard_end = xdp_data_hard_end(xdp); /* use xdp->frame_sz */ > @@ -6889,6 +6924,10 @@ xdp_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) > return &bpf_xdp_adjust_tail_proto; > case BPF_FUNC_xdp_adjust_mb_header: > return &bpf_xdp_adjust_mb_header_proto; > + case BPF_FUNC_xdp_get_frag_count: > + return &bpf_xdp_get_frag_count_proto; > + case BPF_FUNC_xdp_get_frags_total_size: > + return &bpf_xdp_get_frags_total_size_proto; > case BPF_FUNC_fib_lookup: > return &bpf_xdp_fib_lookup_proto; > #ifdef CONFIG_INET > diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h > index 392d52a2ecef..dd4669096cbb 100644 > --- a/tools/include/uapi/linux/bpf.h > +++ b/tools/include/uapi/linux/bpf.h > @@ -3591,6 +3591,18 @@ union bpf_attr { > * > * Return > * 0 on success, or a negative error in case of failure. > + * > + * int bpf_xdp_get_frag_count(struct xdp_buff *xdp_md) > + * Description > + * Get the total number of frags for a given packet. > + * Return > + * The number of frags > + * > + * int bpf_xdp_get_frags_total_size(struct xdp_buff *xdp_md) > + * Description > + * Get the total size of frags for a given packet. > + * Return > + * The total size of frags for a given packet. > */ > #define __BPF_FUNC_MAPPER(FN) \ > FN(unspec), \ > @@ -3743,6 +3755,8 @@ union bpf_attr { > FN(d_path), \ > FN(copy_from_user), \ > FN(xdp_adjust_mb_header), \ > + FN(xdp_get_frag_count), \ > + FN(xdp_get_frags_total_size), \ > /* */ > > /* integer value in 'imm' field of BPF_CALL instruction selects which helper > -- > 2.26.2 >