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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,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 CE0DDCA9ECF for ; Thu, 31 Oct 2019 23:48:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id ADA0B208C0 for ; Thu, 31 Oct 2019 23:48:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728333AbfJaXsL (ORCPT ); Thu, 31 Oct 2019 19:48:11 -0400 Received: from www62.your-server.de ([213.133.104.62]:52048 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727611AbfJaXsK (ORCPT ); Thu, 31 Oct 2019 19:48:10 -0400 Received: from 38.249.197.178.dynamic.dsl-lte-bonding.lssmb00p-msn.res.cust.swisscom.ch ([178.197.249.38] helo=localhost) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1iQKAe-0001Mk-Ic; Fri, 01 Nov 2019 00:48:05 +0100 Date: Fri, 1 Nov 2019 00:48:04 +0100 From: Daniel Borkmann To: =?iso-8859-1?Q?Bj=F6rn_T=F6pel?= Cc: netdev@vger.kernel.org, ast@kernel.org, jakub.kicinski@netronome.com, Maciej Fijalkowski , bpf@vger.kernel.org, magnus.karlsson@gmail.com, magnus.karlsson@intel.com, jonathan.lemon@gmail.com, toke@redhat.com Subject: Re: [PATCH bpf-next v4 2/3] bpf: implement map_gen_lookup() callback for XSKMAP Message-ID: <20191031234804.GA20080@pc-63.home> References: <20191031084749.14626-1-bjorn.topel@gmail.com> <20191031084749.14626-3-bjorn.topel@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191031084749.14626-3-bjorn.topel@gmail.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.101.4/25619/Thu Oct 31 09:55:29 2019) Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Oct 31, 2019 at 09:47:48AM +0100, Björn Töpel wrote: > From: Maciej Fijalkowski > > Inline the xsk_map_lookup_elem() via implementing the map_gen_lookup() > callback. This results in emitting the bpf instructions in place of > bpf_map_lookup_elem() helper call and better performance of bpf > programs. > > Acked-by: Jonathan Lemon > Signed-off-by: Maciej Fijalkowski > --- > kernel/bpf/xskmap.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c > index edcbd863650e..fa32f775b4de 100644 > --- a/kernel/bpf/xskmap.c > +++ b/kernel/bpf/xskmap.c > @@ -163,6 +163,22 @@ struct xdp_sock *__xsk_map_lookup_elem(struct bpf_map *map, u32 key) > return xs; > } > > +static u32 xsk_map_gen_lookup(struct bpf_map *map, struct bpf_insn *insn_buf) > +{ > + const int ret = BPF_REG_0, mp = BPF_REG_1, index = BPF_REG_2; > + struct bpf_insn *insn = insn_buf; > + > + *insn++ = BPF_LDX_MEM(BPF_W, ret, index, 0); > + *insn++ = BPF_JMP_IMM(BPF_JGE, ret, map->max_entries, 5); > + *insn++ = BPF_ALU64_IMM(BPF_LSH, ret, ilog2(sizeof(struct xsk_sock *))); > + *insn++ = BPF_ALU64_IMM(BPF_ADD, mp, offsetof(struct xsk_map, xsk_map)); > + *insn++ = BPF_ALU64_REG(BPF_ADD, ret, mp); > + *insn++ = BPF_LDX_MEM(BPF_DW, ret, ret, 0); Your map slots are always exactly sizeof(struct xdp_sock *), right? Wouldn't this BPF_DW crash on 32 bit? Meaning, it would have to be BPF_LDX_MEM(BPF_SIZEOF(struct xsk_sock *), ...)? > + *insn++ = BPF_JMP_IMM(BPF_JA, 0, 0, 1); > + *insn++ = BPF_MOV64_IMM(ret, 0); > + return insn - insn_buf; > +} > + > int __xsk_map_redirect(struct bpf_map *map, struct xdp_buff *xdp, > struct xdp_sock *xs) > { > @@ -303,6 +319,7 @@ const struct bpf_map_ops xsk_map_ops = { > .map_free = xsk_map_free, > .map_get_next_key = xsk_map_get_next_key, > .map_lookup_elem = xsk_map_lookup_elem, > + .map_gen_lookup = xsk_map_gen_lookup, > .map_lookup_elem_sys_only = xsk_map_lookup_elem_sys_only, > .map_update_elem = xsk_map_update_elem, > .map_delete_elem = xsk_map_delete_elem, > -- > 2.20.1 >