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=-3.9 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS autolearn=no 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 05F39C352A4 for ; Wed, 12 Feb 2020 18:42:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C3FFE24685 for ; Wed, 12 Feb 2020 18:42:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="SFbbq2ja"; dkim=pass (1024-bit key) header.d=fb.onmicrosoft.com header.i=@fb.onmicrosoft.com header.b="kh1TXYqO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728840AbgBLSmH (ORCPT ); Wed, 12 Feb 2020 13:42:07 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:27332 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727054AbgBLSmH (ORCPT ); Wed, 12 Feb 2020 13:42:07 -0500 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id 01CIY8Mb014512; Wed, 12 Feb 2020 10:40:56 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : references : in-reply-to : content-type : content-id : content-transfer-encoding : mime-version; s=facebook; bh=Pfm4Ins0onsbySSV3DIQ7I4/jrcIZZtmUHPZuWknubc=; b=SFbbq2jaqCJ4AL4M1B1afysTvABJPaCqg+fthJXlyF3uJK7H8W6HmhZlVGvAKj+Rk6To 1ShGkNrHKEEfqLiIh/TmMfqEXDjy6KKglDIaALTmeEA/LGShsPvhHWxEqD1EAO0CE1tH S6+TMkRLyYMQUYuiH/whK0hQvIip+2FuU8E= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 2y4607mqph-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Wed, 12 Feb 2020 10:40:56 -0800 Received: from NAM02-SN1-obe.outbound.protection.outlook.com (100.104.98.9) by o365-in.thefacebook.com (100.104.94.196) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1779.2; Wed, 12 Feb 2020 10:40:55 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=dfEGi+55sWBdBuUtWE9OkT2jUO/LLZKcvD2WhpBTtoxKhFhEa1xId/x/6vANIsm+Ma9NaLL5zKmS8B3oH1Pvz48HworcHMhxn6wFo4L5UNVBntLOjWaPrEUN8fZRIamcoutqkRTF6mRZL8R/BKwrVv4+cdiZ9UnGIP0G8RsA52IPoZVAXzrNEQTXfOK0odr9nkYHG+a2pipaJr/9yCdEGA7HN4dCk1SfqS9Nw5YPsa5bmMU480SxGt20paie+sylXioF22HMMeiXbwRQxlWHAKw3QQP1vsaMi9m6IZDyTSegRfKl1kFRkUT0cIxkP5LMAzxSdI4zlxQeVkWlf20g+w== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Pfm4Ins0onsbySSV3DIQ7I4/jrcIZZtmUHPZuWknubc=; b=khRsyslNKhd6L+zqhzjiByGW13KUL9H1C6ANi9X4kvaHE97y5UkxIxKr7g3Z2bvDXINDJCUScXtX1ZZ1L/gQOwsXCjnGtNAyHO8XHxeIir9kq67jz/jC32kp1rrRrmjG8UYQCG9fmI5AGEBOpuhLg4tBEake7CxZvuAZxY7Sc65/cz4rXfH0GxGvqVq4w93lLMyndgF7JJy/s6f4iY4tVOHMyeD/W/qf3tKVpCnhkLlXlBHIaKJ3Xoz2ifBxYU+e1B6Vv+70QUZ4Ph8icAa2IXI+h5W4Wj2eu2yWqZHaflnyjUobqOXi4+L40+Vhp0QG3BWDzimGyVxpSV5YVKPn+A== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=fb.com; dmarc=pass action=none header.from=fb.com; dkim=pass header.d=fb.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.onmicrosoft.com; s=selector2-fb-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=Pfm4Ins0onsbySSV3DIQ7I4/jrcIZZtmUHPZuWknubc=; b=kh1TXYqOPF45bTjmB61KDucMYauR87W1FfSa08z2HSeIfJxGUEVmhN9O+51DF1sT8hAjKJr5f3xBBkaPOjtRO9fJKTDAIQBD7Ynd6RmgliDgtbw7fDA3+EXNIA8XHvZKTX5ID6eFr22kl1SiDZUSjU5PpZxEDuoCPcHmSHWO5bw= Received: from MW2PR1501MB2171.namprd15.prod.outlook.com (52.132.153.155) by MW2PR1501MB2044.namprd15.prod.outlook.com (52.132.147.155) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.2707.28; Wed, 12 Feb 2020 18:40:54 +0000 Received: from MW2PR1501MB2171.namprd15.prod.outlook.com ([fe80::492d:3e00:17dc:6b30]) by MW2PR1501MB2171.namprd15.prod.outlook.com ([fe80::492d:3e00:17dc:6b30%7]) with mapi id 15.20.2707.030; Wed, 12 Feb 2020 18:40:54 +0000 From: Song Liu To: Andrii Nakryiko CC: Eelco Chaudron , bpf , "David S. Miller" , Networking , "Alexei Starovoitov" , Daniel Borkmann , "Martin Lau" , Yonghong Song , Andrii Nakryiko , =?iso-8859-1?Q?Toke_H=F8iland-J=F8rgensen?= Subject: Re: [PATCH bpf-next] libbpf: Add support for dynamic program attach target Thread-Topic: [PATCH bpf-next] libbpf: Add support for dynamic program attach target Thread-Index: AQHV4aBmkuDy8vU+NUWdt8DKhmBCX6gX0g0AgAAGM4CAAAUIAIAAA/gAgAABgYCAAAHmgA== Date: Wed, 12 Feb 2020 18:40:54 +0000 Message-ID: <04B1C476-5ABC-4F98-A5A3-5A2E124B516F@fb.com> References: <158151067149.71757.2222114135650741733.stgit@xdp-tutorial> <628E972C-1156-46F8-AC61-DB0D38C34C81@fb.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-mailer: Apple Mail (2.3608.60.0.2.5) x-originating-ip: [2620:10d:c090:400::5:f48e] x-ms-publictraffictype: Email x-ms-office365-filtering-correlation-id: 8b6ed840-c640-4e31-3e4c-08d7afeb178c x-ms-traffictypediagnostic: MW2PR1501MB2044: x-ms-exchange-transport-forked: True x-microsoft-antispam-prvs: x-fb-source: Internal x-ms-oob-tlc-oobclassifiers: OLM:7691; x-forefront-prvs: 0311124FA9 x-forefront-antispam-report: SFV:NSPM;SFS:(10019020)(39860400002)(396003)(136003)(346002)(366004)(376002)(189003)(199004)(36756003)(54906003)(6506007)(8936002)(66556008)(5660300002)(4326008)(66446008)(76116006)(71200400001)(66946007)(316002)(8676002)(64756008)(53546011)(6486002)(81166006)(81156014)(6916009)(33656002)(66476007)(478600001)(6512007)(2616005)(186003)(86362001)(2906002)(21314003);DIR:OUT;SFP:1102;SCL:1;SRVR:MW2PR1501MB2044;H:MW2PR1501MB2171.namprd15.prod.outlook.com;FPR:;SPF:None;LANG:en;PTR:InfoNoRecords;MX:1;A:1; received-spf: None (protection.outlook.com: fb.com does not designate permitted sender hosts) x-ms-exchange-senderadcheck: 1 x-microsoft-antispam: BCL:0; x-microsoft-antispam-message-info: QRdXAcdlg1I8HZsbjfLjQJmjmTYwH6HTwNKB9vzPvVRT65XgCEw7oC1jWHCj4y8zOGJ+sfzNuNdV1iOIfVy+LBcIp52QoF8jWcuH6MtymCIX2Fi1J+ne0J6KjR89NmVOeEOQgdyh6VZnTx3CBnk1MLaAKp/9AUJuAl4LJUXOW/LjIqpP1RD/OiTET1//3YAQvsRp0bBVO1luHioAPXd6I75ghQ21WEGsyOcdjulNsHYnHf0QPiQ69T94oENEHY35AzW0n+/NSgbWKiY9kkGCTMTezQxIJhAS7F85rZZ76AkSEW6NrD5X6CzRMZloO71UII/ZeZgz6P0qhkjH9rIPYTiErCXlABed2UObx2JV6qkVoDFdWOC4dGJestsgJUX5aVZhLYH4pWLCRhRVPbQYqKTA7QXiD6ZzD1xdnrg9BE/iq4qARK9Fho7aTbUenB80j/BegJAWTCn78J1f1Zrc+wnjXKpiCtQ/0U1j3SxpQt944+QtIFgWf0cEkNHWj+2U x-ms-exchange-antispam-messagedata: nPFqG5sXd0iHRRU8tnKXEtpxe8bWWiGXNhSzlXuoxn1IQP2b1BPQzCpvCuz1h4knlKl3Yih1cDJGSXOxSL+oUWUxNMwRvlUInMtWhAa/dIMDGNpWvVUiUmXvGLrvnZT7T5O1WKUOvg+2ttzpGdh3o41KxrYEQMe6bqFDxIldfsZZkHZDaHPZGiQ5/WpOKspz Content-Type: text/plain; charset="iso-8859-1" Content-ID: <93C484F6E903FC4CB103FDE0B6FDB4CC@namprd15.prod.outlook.com> Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-Network-Message-Id: 8b6ed840-c640-4e31-3e4c-08d7afeb178c X-MS-Exchange-CrossTenant-originalarrivaltime: 12 Feb 2020 18:40:54.2337 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: /jBaAJFZDDx7jGUT2G9kmkOoyNaGMLuiYiUEXLZJ/feB+bTKYCY1wf1xEt8YMsKf3zDG4rEn6AQhax4aq0k+OQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW2PR1501MB2044 X-OriginatorOrg: fb.com X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.138,18.0.572 definitions=2020-02-12_08:2020-02-12,2020-02-12 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 phishscore=0 bulkscore=0 adultscore=0 impostorscore=0 malwarescore=0 suspectscore=0 priorityscore=1501 lowpriorityscore=0 spamscore=0 mlxscore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2001150001 definitions=main-2002120133 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org > On Feb 12, 2020, at 10:34 AM, Andrii Nakryiko = wrote: >=20 > On Wed, Feb 12, 2020 at 10:29 AM Song Liu wrote: >>=20 >>=20 >>=20 >>> On Feb 12, 2020, at 10:14 AM, Andrii Nakryiko wrote: >>>=20 >>> On Wed, Feb 12, 2020 at 10:07 AM Song Liu wrote= : >>>>=20 >>>>=20 >>>>=20 >>>>> On Feb 12, 2020, at 9:34 AM, Andrii Nakryiko wrote: >>>>>=20 >>>>> On Wed, Feb 12, 2020 at 4:32 AM Eelco Chaudron = wrote: >>>>>>=20 >>>>>> Currently when you want to attach a trace program to a bpf program >>>>>> the section name needs to match the tracepoint/function semantics. >>>>>>=20 >>>>>> However the addition of the bpf_program__set_attach_target() API >>>>>> allows you to specify the tracepoint/function dynamically. >>>>>>=20 >>>>>> The call flow would look something like this: >>>>>>=20 >>>>>> xdp_fd =3D bpf_prog_get_fd_by_id(id); >>>>>> trace_obj =3D bpf_object__open_file("func.o", NULL); >>>>>> prog =3D bpf_object__find_program_by_title(trace_obj, >>>>>> "fentry/myfunc"); >>>>>> bpf_program__set_attach_target(prog, xdp_fd, >>>>>> "fentry/xdpfilt_blk_all"); >>>>>> bpf_object__load(trace_obj) >>>>>>=20 >>>>>> Signed-off-by: Eelco Chaudron >>>>=20 >>>>=20 >>>> I am trying to solve the same problem with slightly different approach= . >>>>=20 >>>> It works as the following (with skeleton): >>>>=20 >>>> obj =3D myobject_bpf__open_opts(&opts); >>>> bpf_object__for_each_program(prog, obj->obj) >>>> bpf_program__overwrite_section_name(prog, new_names[id++= ]); >>>> err =3D myobject_bpf__load(obj); >>>>=20 >>>> I don't have very strong preference. But I think my approach is simple= r? >>>=20 >>> I prefer bpf_program__set_attach_target() approach. Section name is a >>> program identifier and a *hint* for libbpf to determine program type, >>> attach type, and whatever else makes sense. But there still should be >>> an API to set all that manually at runtime, thus >>> bpf_program__set_attach_target(). Doing same by overriding section >>> name feels like a hack, plus it doesn't handle overriding >>> attach_program_fd at all. >>=20 >> We already have bpf_object_open_opts to handle different attach_program_= fd. >=20 > Not really, because open_opts apply to bpf_object and all its > bpf_programs, not to individual bpf_program. So it works only if BPF > application has only one BPF program. If you have many, you can only > set the same attach_program_fd for all of them. Basically, open_opts' > attach_prog_fd should be treated as a default or fallback > attach_prog_fd. Fair enough. I will use set_attach_target in my code.=20 >=20 >> Can we depreciate bpf_object_open_opts.attach_prog_fd with the >> bpf_program__set_attach_target() approach? >=20 > bpf_program__set_attach_target() overrides attach_prog_fd, yes. But we > can't just deprecate that option because it's part of an API already, > even though adding it to open opts was probably a mistake. But for > simple BPF apps with single BPF program it does work fine, so... Maybe add a warning saying "attach_prog_fd is deprecated, xxx"? Thanks, Song=