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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 85605C433F5 for ; Wed, 12 Jan 2022 22:05:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230142AbiALWFC (ORCPT ); Wed, 12 Jan 2022 17:05:02 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:37698 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230117AbiALWFC (ORCPT ); Wed, 12 Jan 2022 17:05:02 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1642025101; 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: in-reply-to:in-reply-to:references:references; bh=Vj/JjjjjtW+vABd5/EQjNU1tF2VEAkq+b64gZeNi07o=; b=QyDBLhXKQEQL5w1lvsjVTan8+3MiqAbC84Xvpj+xyq1hQytlON+9bLCHQDVxDMxqhJr+YI DC3c4uFfY/ImWHooMIwOjtTaBobME+qnMtDgkj685pT3p4rsRvA7M/lT27d7wi1NuOkmnx QuO5gsYqKJGfPFvEBIU161gEDXA50Yw= Received: from mail-ed1-f72.google.com (mail-ed1-f72.google.com [209.85.208.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-43-U2rRKOOoPnCrR_bRDHBmqQ-1; Wed, 12 Jan 2022 17:04:59 -0500 X-MC-Unique: U2rRKOOoPnCrR_bRDHBmqQ-1 Received: by mail-ed1-f72.google.com with SMTP id h1-20020aa7cdc1000000b0040042dd2fe4so2217741edw.17 for ; Wed, 12 Jan 2022 14:04:59 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:in-reply-to:references:date :message-id:mime-version; bh=Vj/JjjjjtW+vABd5/EQjNU1tF2VEAkq+b64gZeNi07o=; b=5aKTWnuBFDc7C/TtwdK0Du7ncbpQODl7wOBhLoKQTbOyQOBDIcTe/OUKOzQF9i4Jep nteFcDQbc8bHyJQ+ufGE70+komDROtED9PjZIC0c2BAL4zYv/mM/eURRlq83CqYL3ui5 fsLIhCkPJpIl/IIGBJh1E01kvDbC3Nsi/5GFINMf9+XkJj91yk6TZATt91op37LRafME xPBn6FMdNiSmYrbujDUZvGWyiMafhwX4zy4D53AAsEADcz87JSn7Qp9PO/THujyfdne5 8qXaEmzNL3O064L44lcY7cspYVlW89k602coLYMYiiognEcI4rbwNmnbTzi2gVemMTnR n1zg== X-Gm-Message-State: AOAM530cP9fRcyAOUUKsjpqbe6U6z/PaN/Ks/cAYDo2U0OdwlHhb9Rgf EvSYguUQsqGVuhtmPnI+3gOJjxIfHkDxF7DyHrWe8nYH2XCCR0Juh5c6cZS6FkdqxCPUcYTdXS/ 3lhEr0dy52nUZ X-Received: by 2002:a05:6402:22d2:: with SMTP id dm18mr639219edb.410.1642025098106; Wed, 12 Jan 2022 14:04:58 -0800 (PST) X-Google-Smtp-Source: ABdhPJyXJbMa1ILQCIyYSHsZZt5DmjeICi3M6tZjtTstvCMe4mxyXdv6+tHudLOdLDt5blgTqBChwg== X-Received: by 2002:a05:6402:22d2:: with SMTP id dm18mr639185edb.410.1642025097704; Wed, 12 Jan 2022 14:04:57 -0800 (PST) Received: from alrua-x1.borgediget.toke.dk ([45.145.92.2]) by smtp.gmail.com with ESMTPSA id j4sm381760edk.64.2022.01.12.14.04.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 12 Jan 2022 14:04:57 -0800 (PST) Received: by alrua-x1.borgediget.toke.dk (Postfix, from userid 1000) id 91BA21802BD; Wed, 12 Jan 2022 23:04:55 +0100 (CET) From: Toke =?utf-8?Q?H=C3=B8iland-J=C3=B8rgensen?= To: Lorenzo Bianconi , Zvi Effron Cc: Alexei Starovoitov , Andrii Nakryiko , Lorenzo Bianconi , bpf , Networking , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Shay Agroskin , john fastabend , David Ahern , Jesper Dangaard Brouer , Eelco Chaudron , Jason Wang , Alexander Duyck , Saeed Mahameed , Maciej Fijalkowski , Magnus Karlsson , tirthendu.sarkar@intel.com Subject: Re: [PATCH v21 bpf-next 18/23] libbpf: Add SEC name for xdp_mb programs In-Reply-To: References: X-Clacks-Overhead: GNU Terry Pratchett Date: Wed, 12 Jan 2022 23:04:55 +0100 Message-ID: <8735lshapk.fsf@toke.dk> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Lorenzo Bianconi writes: >> On Wed, Jan 12, 2022 at 11:47 AM Alexei Starovoitov >> wrote: >> > >> > On Wed, Jan 12, 2022 at 11:21 AM Andrii Nakryiko >> > wrote: >> > > >> > > On Wed, Jan 12, 2022 at 11:17 AM Alexei Starovoitov >> > > wrote: >> > > > >> > > > On Wed, Jan 12, 2022 at 10:24 AM Andrii Nakryiko >> > > > wrote: >> > > > > >> > > > > On Wed, Jan 12, 2022 at 10:18 AM Lorenzo Bianconi wrote: >> > > > > > >> > > > > > > On Sun, Jan 9, 2022 at 7:05 AM Lorenzo Bianconi wrote: >> > > > > > > > >> > > > > > > > Introduce support for the following SEC entries for XDP multi-buff >> > > > > > > > property: >> > > > > > > > - SEC("xdp_mb/") >> > > > > > > > - SEC("xdp_devmap_mb/") >> > > > > > > > - SEC("xdp_cpumap_mb/") >> > > > > > > >> > > > > > > Libbpf seemed to went with . rule (e.g., fentry.s for >> > > > > > > sleepable, seems like we'll have kprobe.multi or something along >> > > > > > > those lines as well), so let's stay consistent and call this "xdp_mb", >> > > > > > > "xdp_devmap.mb", "xdp_cpumap.mb" (btw, is "mb" really all that >> > > > > > > recognizable? would ".multibuf" be too verbose?). Also, why the "/" >> > > > > > > part? Also it shouldn't be "sloppy" either. Neither expected attach >> > > > > > > type should be optional. Also not sure SEC_ATTACHABLE is needed. So >> > > > > > > at most it should be SEC_XDP_MB, probably. >> > > > > > >> > > > > > ack, I fine with it. Something like: >> > > > > > >> > > > > > SEC_DEF("lsm.s/", LSM, BPF_LSM_MAC, SEC_ATTACH_BTF | SEC_SLEEPABLE, attach_lsm), >> > > > > > SEC_DEF("iter/", TRACING, BPF_TRACE_ITER, SEC_ATTACH_BTF, attach_iter), >> > > > > > SEC_DEF("syscall", SYSCALL, 0, SEC_SLEEPABLE), >> > > > > > + SEC_DEF("xdp_devmap.multibuf", XDP, BPF_XDP_DEVMAP, 0), >> > > > > > SEC_DEF("xdp_devmap/", XDP, BPF_XDP_DEVMAP, SEC_ATTACHABLE), >> > > > > > + SEC_DEF("xdp_cpumap.multibuf", XDP, BPF_XDP_CPUMAP, 0), >> > > > > > SEC_DEF("xdp_cpumap/", XDP, BPF_XDP_CPUMAP, SEC_ATTACHABLE), >> > > > > > + SEC_DEF("xdp.multibuf", XDP, BPF_XDP, 0), >> > > > > >> > > > > yep, but please use SEC_NONE instead of zero >> > > > > >> > > > > > SEC_DEF("xdp", XDP, BPF_XDP, SEC_ATTACHABLE_OPT | SEC_SLOPPY_PFX), >> > > > > > SEC_DEF("perf_event", PERF_EVENT, 0, SEC_NONE | SEC_SLOPPY_PFX), >> > > > > > SEC_DEF("lwt_in", LWT_IN, 0, SEC_NONE | SEC_SLOPPY_PFX), >> > > > > > >> > > > > > > >> > > > > > > > >> > > > > > > > Acked-by: Toke Hoiland-Jorgensen >> > > > > > > > Acked-by: John Fastabend >> > > > > > > > Signed-off-by: Lorenzo Bianconi >> > > > > > > > --- >> > > > > > > > tools/lib/bpf/libbpf.c | 8 ++++++++ >> > > > > > > > 1 file changed, 8 insertions(+) >> > > > > > > > >> > > > > > > > diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c >> > > > > > > > index 7f10dd501a52..c93f6afef96c 100644 >> > > > > > > > --- a/tools/lib/bpf/libbpf.c >> > > > > > > > +++ b/tools/lib/bpf/libbpf.c >> > > > > > > > @@ -235,6 +235,8 @@ enum sec_def_flags { >> > > > > > > > SEC_SLEEPABLE = 8, >> > > > > > > > /* allow non-strict prefix matching */ >> > > > > > > > SEC_SLOPPY_PFX = 16, >> > > > > > > > + /* BPF program support XDP multi-buff */ >> > > > > > > > + SEC_XDP_MB = 32, >> > > > > > > > }; >> > > > > > > > >> > > > > > > > struct bpf_sec_def { >> > > > > > > > @@ -6562,6 +6564,9 @@ static int libbpf_preload_prog(struct bpf_program *prog, >> > > > > > > > if (def & SEC_SLEEPABLE) >> > > > > > > > opts->prog_flags |= BPF_F_SLEEPABLE; >> > > > > > > > >> > > > > > > > + if (prog->type == BPF_PROG_TYPE_XDP && (def & SEC_XDP_MB)) >> > > > > > > > + opts->prog_flags |= BPF_F_XDP_MB; >> > > > > > > >> > > > > > > I'd say you don't even need SEC_XDP_MB flag at all, you can just check >> > > > > > > that prog->sec_name is one of "xdp.mb", "xdp_devmap.mb" or >> > > > > > > "xdp_cpumap.mb" and add the flag. SEC_XDP_MB doesn't seem generic >> > > > > > > enough to warrant a flag. >> > > > > > >> > > > > > ack, something like: >> > > > > > >> > > > > > + if (prog->type == BPF_PROG_TYPE_XDP && >> > > > > > + (!strcmp(prog->sec_name, "xdp_devmap.multibuf") || >> > > > > > + !strcmp(prog->sec_name, "xdp_cpumap.multibuf") || >> > > > > > + !strcmp(prog->sec_name, "xdp.multibuf"))) >> > > > > > + opts->prog_flags |= BPF_F_XDP_MB; >> > > > > >> > > > > yep, can also simplify it a bit with strstr(prog->sec_name, >> > > > > ".multibuf") instead of three strcmp >> > > > >> > > > Maybe ".mb" ? >> > > > ".multibuf" is too verbose. >> > > > We're fine with ".s" for sleepable :) >> > > >> > > >> > > I had reservations about "mb" because the first and strong association >> > > is "megabyte", not "multibuf". And it's not like anyone would have >> > > tens of those programs in a single file so that ".multibuf" becomes >> > > way too verbose. But I don't feel too strongly about this, if the >> > > consensus is on ".mb". >> > >> > The rest of the patches are using _mb everywhere. >> > I would keep libbpf consistent. >> >> Should the rest of the patches maybe use "multibuf" instead of "mb"? I've been >> following this patch series closely and excitedly, and I keep having to remind >> myself that "mb" is "multibuff" and not "megabyte". If I'm having to correct >> myself while following the patch series, I'm wondering if future confusion is >> inevitable? >> >> But, is it enough confusion to be worth updating many other patches? I'm not >> sure. >> >> I agree consistency is more important than the specific term we're consistent >> on. > > I would prefer to keep the "_mb" postfix, but naming is hard and I am > polarized :) I would lean towards keeping _mb as well, but if it does have to be changed why not _mbuf? At least that's not quite as verbose :) -Toke