From patchwork Sat Nov 9 08:06:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1192372 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="CfMJudFm"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4798qT0RZcz9sNx for ; Sat, 9 Nov 2019 19:06:45 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726405AbfKIIGn (ORCPT ); Sat, 9 Nov 2019 03:06:43 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:60914 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726194AbfKIIGm (ORCPT ); Sat, 9 Nov 2019 03:06:42 -0500 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.42/8.16.0.42) with SMTP id xA984koA023666 for ; Sat, 9 Nov 2019 00:06:40 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=kQyk6ZTQKfvod+yRKy0eWswT6wNyPhLM/cEbxQ3VpAk=; b=CfMJudFmNu/ty7Rg0inVFCFMPuzi/inNsA6KSjgUTh3La2F46kYubKUPytSHrzJag4ev pU58727N+GiPhm8kQ02FesbXSd0HBGSqaU4Xq+ks6tqmdz0uSLcTFmStELfasBiiIOly eQZ/2QehNh2YNEd5uj+w5Hh4Cf0SmU8CZsU= Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net with ESMTP id 2w5p7m0hq6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sat, 09 Nov 2019 00:06:40 -0800 Received: from 2401:db00:12:9028:face:0:29:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Sat, 9 Nov 2019 00:06:39 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 817DA2EC1AC6; Sat, 9 Nov 2019 00:06:38 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH v2 bpf-next 2/3] libbpf: make global data internal arrays mmap()-able, if possible Date: Sat, 9 Nov 2019 00:06:31 -0800 Message-ID: <20191109080633.2855561-3-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191109080633.2855561-1-andriin@fb.com> References: <20191109080633.2855561-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95, 18.0.572 definitions=2019-11-09_02:2019-11-08, 2019-11-09 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=999 bulkscore=0 suspectscore=8 malwarescore=0 mlxscore=0 adultscore=0 phishscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1911090085 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add detection of BPF_F_MMAPABLE flag support for arrays and add it as an extra flag to internal global data maps, if supported by kernel. This allows users to memory-map global data and use it without BPF map operations, greatly simplifying user experience. Acked-by: Song Liu Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index fde6cb3e5d41..d32899e50f8a 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -142,6 +142,8 @@ struct bpf_capabilities { __u32 btf_func:1; /* BTF_KIND_VAR and BTF_KIND_DATASEC support */ __u32 btf_datasec:1; + /* BPF_F_MMAPABLE is supported for arrays */ + __u32 array_mmap:1; }; /* @@ -855,8 +857,6 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, pr_warn("failed to alloc map name\n"); return -ENOMEM; } - pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n", - map_name, map->sec_idx, map->sec_offset); def = &map->def; def->type = BPF_MAP_TYPE_ARRAY; @@ -864,6 +864,12 @@ bpf_object__init_internal_map(struct bpf_object *obj, enum libbpf_map_type type, def->value_size = data->d_size; def->max_entries = 1; def->map_flags = type == LIBBPF_MAP_RODATA ? BPF_F_RDONLY_PROG : 0; + if (obj->caps.array_mmap) + def->map_flags |= BPF_F_MMAPABLE; + + pr_debug("map '%s' (global data): at sec_idx %d, offset %zu, flags %x.\n", + map_name, map->sec_idx, map->sec_offset, def->map_flags); + if (data_buff) { *data_buff = malloc(data->d_size); if (!*data_buff) { @@ -2158,6 +2164,26 @@ static int bpf_object__probe_btf_datasec(struct bpf_object *obj) return 0; } +static int bpf_object__probe_array_mmap(struct bpf_object *obj) +{ + struct bpf_create_map_attr attr = { + .map_type = BPF_MAP_TYPE_ARRAY, + .map_flags = BPF_F_MMAPABLE, + .key_size = sizeof(int), + .value_size = sizeof(int), + .max_entries = 1, + }; + int fd = bpf_create_map_xattr(&attr); + + if (fd >= 0) { + obj->caps.array_mmap = 1; + close(fd); + return 1; + } + + return 0; +} + static int bpf_object__probe_caps(struct bpf_object *obj) { @@ -2166,6 +2192,7 @@ bpf_object__probe_caps(struct bpf_object *obj) bpf_object__probe_global_data, bpf_object__probe_btf_func, bpf_object__probe_btf_datasec, + bpf_object__probe_array_mmap, }; int i, ret;