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=-6.7 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 410FBFA372C for ; Fri, 8 Nov 2019 19:35:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 146DE206C3 for ; Fri, 8 Nov 2019 19:35:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HM3voJSX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732046AbfKHTfM (ORCPT ); Fri, 8 Nov 2019 14:35:12 -0500 Received: from mail-qv1-f66.google.com ([209.85.219.66]:42675 "EHLO mail-qv1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727233AbfKHTfM (ORCPT ); Fri, 8 Nov 2019 14:35:12 -0500 Received: by mail-qv1-f66.google.com with SMTP id c9so2654416qvz.9; Fri, 08 Nov 2019 11:35:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ITHyFtFHHFPfxKluOYKDyQg82wymRlt7RNbYl5V4C3A=; b=HM3voJSX9CsunmC/o93xStm0HSMoKnsyEHfBlDFUgRwbaldioYMs0+uKdZLkMjgNFl YSTD9OLDltGlWzB/MB9jAzwakn1t1bvqFua6ZkKAiwqAXQUjT9cDtdGSnQ47NCIxxRUw bsHeetlUFSUuSAU/4cyaSIfiXmqxrnHv5FolPlj5JkbycxiW48i9OiadjchfViQzIuZT yd8uNPu2MtYUFw4bP6+kiC/VxyQyCFnNB7e51vZ+3fqAVahwRBauMMJQ/r5A0kZp3zEP UfQQBIHz7BlbrFWUz/HmAftoxr2eQU2trYHqmfbYbUj60y6YGo2ZHhgSsvZnD0fdodKb jnvQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ITHyFtFHHFPfxKluOYKDyQg82wymRlt7RNbYl5V4C3A=; b=INMvDgDMpF5BaV11exdvp38fKMWAwuMvZsxydtaOX+SKmVc2XKOjaSuHRIkCn5nBGl 4ylKFUkE8bJ89solxQD60sglwKBitMsDKZs0ySj2CbKZUx+m4aVgmxo7pfRuZywn77rE t65o2o/SobdfypaVnUPV79pmL9ILp9Gcye9JTQnwRI6G3AUXbSPy+h+MrQ9hoW5LhAd9 vd5wm7ZOHS3gWvqdDcr/2K/JHuQVvnOJZ4RkM5BloBDkBGiQqE44RMZy3v6bi5nk+mXQ l6tbqrdaFtHZih6KP6IYv+nycL5u/3GAp0ahvbWAKLzoyYlO7wMo0rsKTvI7gKVY/pm4 0Fuw== X-Gm-Message-State: APjAAAXUZa/zchK1IevYNPxuYZioHmvHdt5BbQ3kZhGHRSJ1XbQ90WM4 O4jlbdIjgFEEdccWcZDg89k/to4bvfaA1j2Msys= X-Google-Smtp-Source: APXvYqxVOmd1n/J1aStd7JbFYRI6e/ntrDYLzaEUifQHCtQCWcsRcFmSYo+Z0u3uKJ9loEjp4RAQclYvdclGL+JrStU= X-Received: by 2002:ad4:4e4a:: with SMTP id eb10mr10735976qvb.228.1573241710527; Fri, 08 Nov 2019 11:35:10 -0800 (PST) MIME-Version: 1.0 References: <20191108042041.1549144-1-andriin@fb.com> <20191108042041.1549144-3-andriin@fb.com> In-Reply-To: From: Andrii Nakryiko Date: Fri, 8 Nov 2019 11:34:59 -0800 Message-ID: Subject: Re: [PATCH bpf-next 2/3] libbpf: make global data internal arrays mmap()-able, if possible To: Song Liu Cc: Andrii Nakryiko , bpf , "netdev@vger.kernel.org" , Alexei Starovoitov , "daniel@iogearbox.net" , Kernel Team Content-Type: text/plain; charset="UTF-8" Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org On Thu, Nov 7, 2019 at 10:44 PM Song Liu wrote: > > > > > On Nov 7, 2019, at 8:20 PM, Andrii Nakryiko wrote: > > > > 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. > > > > Signed-off-by: Andrii Nakryiko > > Acked-by: Song Liu > > With nit below. > > > --- > > 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..73607a31a068 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 %u.\n", > > nit: Better print flags as %x. > > sure, will update