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=-6.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 702D0CA9EAF for ; Mon, 21 Oct 2019 11:50:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3F98420659 for ; Mon, 21 Oct 2019 11:50:32 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="EoUoSkZV" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbfJULuc (ORCPT ); Mon, 21 Oct 2019 07:50:32 -0400 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:22146 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727953AbfJULub (ORCPT ); Mon, 21 Oct 2019 07:50:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1571658630; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=KqIaXqYJJipGxJgDMyra1M7Qq5CfHgA1rX/304TpjYk=; b=EoUoSkZVfqamItgQl8EMn/p4QAACbKxmO5r5fab59lGlkPNKp0SmO8Tb7pJ/9P/jhAin+k rkbF6jQipetwfCk5eG9tW0as5rIcU8kSemg/TLdjCSfouaVNGWFcYUIrDygiP1JVodeKa8 RqABqCLUCnjA4Sp108qSR/UvWOtuChc= Received: from mail-lj1-f198.google.com (mail-lj1-f198.google.com [209.85.208.198]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-265-3BnmQRYyPWu65JTIaDDH8Q-1; Mon, 21 Oct 2019 07:50:29 -0400 Received: by mail-lj1-f198.google.com with SMTP id y12so2369362ljc.8 for ; Mon, 21 Oct 2019 04:50:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version:content-transfer-encoding; bh=22ZzJtSLeFV5RwYke/b5z8aSCd1uaqRWmq4dpdrIb2M=; b=GmRflb7TlPBhmxuJGaU8sbB/JgKa6Z78XG/TtrxrAAoggRmYfO/NivwWLAuZ/r+vhX S8ncisDBU4DH7vs9HDOUW9UWc9pTjSGs0ShYt+WTnICHrTpix8NpHJXbpXId23LKWcD1 ajPIcxe5+/JfgKgViavrCJGkipo3GdqxJcs49VNRUFV4R629dCnoXQtwPOuk905G0mTR bAel1uLclbwEwlxLJBULjaRJC3VabuPZOXAzParcV5cLYruTqROcZqNumNBVHacouids xd8Fj9XkFmVL7JRFqqPpBr46Ij7L9xstiNP/vypvX27kBFvb9+SARAFRqrq0i/U6t0P0 R3ww== X-Gm-Message-State: APjAAAWyqrLRcLEYKdA+M3Q04vh7yArLj0yS/iadyhB/xy/AA5nj6E1x NFWzNuYWtwOoSbGFueYC+mbL3roUXLzursxYPj0lNqohdViJU3q/KVNtY3lvuXsAl0Pvfxtxpwt h0vgR9l636CPe X-Received: by 2002:a2e:865a:: with SMTP id i26mr14860441ljj.107.1571658627586; Mon, 21 Oct 2019 04:50:27 -0700 (PDT) X-Google-Smtp-Source: APXvYqyNczjPonFjwpYZEXU76pQodFUabDK3alh7XWG+A3KOjFrGCFb7YhbDPkAD+/RGXwYq7udr6A== X-Received: by 2002:a2e:865a:: with SMTP id i26mr14860419ljj.107.1571658627321; Mon, 21 Oct 2019 04:50:27 -0700 (PDT) Received: from alrua-x1.borgediget.toke.dk ([2a00:7660:6da:443::2]) by smtp.gmail.com with ESMTPSA id w18sm9033946ljd.99.2019.10.21.04.50.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 21 Oct 2019 04:50:26 -0700 (PDT) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id A7CC01800E9; Mon, 21 Oct 2019 13:50:25 +0200 (CEST) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , netdev@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net Cc: =?utf-8?B?QmrDtnJuIFTDtnBlbA==?= , bpf@vger.kernel.org, magnus.karlsson@gmail.com, magnus.karlsson@intel.com, sridhar.samudrala@intel.com Subject: Re: [PATCH bpf-next v2] libbpf: use implicit XSKMAP lookup from AF_XDP XDP program In-Reply-To: <20191021105938.11820-1-bjorn.topel@gmail.com> References: <20191021105938.11820-1-bjorn.topel@gmail.com> X-Clacks-Overhead: GNU Terry Pratchett Date: Mon, 21 Oct 2019 13:50:25 +0200 Message-ID: <87h842qpvi.fsf@toke.dk> MIME-Version: 1.0 X-MC-Unique: 3BnmQRYyPWu65JTIaDDH8Q-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Bj=C3=B6rn T=C3=B6pel writes: > From: Bj=C3=B6rn T=C3=B6pel > > In commit 43e74c0267a3 ("bpf_xdp_redirect_map: Perform map lookup in > eBPF helper") the bpf_redirect_map() helper learned to do map lookup, > which means that the explicit lookup in the XDP program for AF_XDP is > not needed for post-5.3 kernels. > > This commit adds the implicit map lookup with default action, which > improves the performance for the "rx_drop" [1] scenario with ~4%. > > For pre-5.3 kernels, the bpf_redirect_map() returns XDP_ABORTED, and a > fallback path for backward compatibility is entered, where explicit > lookup is still performed. This means a slight regression for older > kernels (an additional bpf_redirect_map() call), but I consider that a > fair punishment for users not upgrading their kernels. ;-) > > v1->v2: Backward compatibility (Toke) [2] > > [1] # xdpsock -i eth0 -z -r > [2] https://lore.kernel.org/bpf/87pnirb3dc.fsf@toke.dk/ > > Suggested-by: Toke H=C3=B8iland-J=C3=B8rgensen > Signed-off-by: Bj=C3=B6rn T=C3=B6pel > --- > tools/lib/bpf/xsk.c | 45 +++++++++++++++++++++++++++++++++++---------- > 1 file changed, 35 insertions(+), 10 deletions(-) > > diff --git a/tools/lib/bpf/xsk.c b/tools/lib/bpf/xsk.c > index b0f532544c91..391a126b3fd8 100644 > --- a/tools/lib/bpf/xsk.c > +++ b/tools/lib/bpf/xsk.c > @@ -274,33 +274,58 @@ static int xsk_load_xdp_prog(struct xsk_socket *xsk= ) > =09/* This is the C-program: > =09 * SEC("xdp_sock") int xdp_sock_prog(struct xdp_md *ctx) > =09 * { > -=09 * int index =3D ctx->rx_queue_index; > +=09 * int ret, index =3D ctx->rx_queue_index; > =09 * > =09 * // A set entry here means that the correspnding queue_id > =09 * // has an active AF_XDP socket bound to it. > +=09 * ret =3D bpf_redirect_map(&xsks_map, index, XDP_PASS); > +=09 * ret &=3D XDP_PASS | XDP_REDIRECT; Why the masking? Looks a bit weird (XDP return codes are not defined as bitmask values), and it's not really needed, is it? -Toke