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=-6.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,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 A1568C433E0 for ; Wed, 10 Mar 2021 13:38:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 785BD64FE0 for ; Wed, 10 Mar 2021 13:38:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234985AbhCJNhf (ORCPT ); Wed, 10 Mar 2021 08:37:35 -0500 Received: from mail.kernel.org ([198.145.29.99]:58594 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233859AbhCJNhF (ORCPT ); Wed, 10 Mar 2021 08:37:05 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 659DA64FD6; Wed, 10 Mar 2021 13:37:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615383424; bh=BhjsV9O/Cb++gTnIBjc2l4D0WTs6uHc/AE5awQZUoYg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=IHToW6IGSL79SQpPRM2ToX7jZnwI1z3kEGhHWeZ1p+g0MdqdZ0VTLRwfWs+jUvA8N i/dxaloQNGGbPwEmhxhXat+hPB9TIhz8vXxREWPZSgtYjuHFD0cNi3brJfzhn1mQWy oGzg6ZVK2g5hVizTj/i+ODgUhVQtx9dNzM3WWoCf9sgoZKS1wIRpAMMm7mZcg4e+fk VFzlzVN676GzGDZQM9hn3XFiNDHpfA0qAfllPq9t//9Lu7c141CyCoDr6fvlpRrXLu 6ztYL5h1IfnJvPAkWH9iHbIB94WqXmp5sLDQxUa4tNceGAijVlUTYfGDvrHomifQ7y 5e3jVOLDS66QA== Received: by quaco.ghostprotocols.net (Postfix, from userid 1000) id BF21540647; Wed, 10 Mar 2021 10:37:01 -0300 (-03) Date: Wed, 10 Mar 2021 10:37:01 -0300 From: Arnaldo Carvalho de Melo To: Andrii Nakryiko Cc: Ilya Leoshkevich , Arnaldo Carvalho de Melo , dwarves@vger.kernel.org, bpf , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Yonghong Song , Heiko Carstens , Vasily Gorbik Subject: Re: [PATCH dwarves v2] btf: Add support for the floating-point types Message-ID: References: <20210308235913.162038-1-iii@linux.ibm.com> <051e4d6b000af07cc65a8dc70f4589fa3bd4be78.camel@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Url: http://acmel.wordpress.com Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Em Tue, Mar 09, 2021 at 08:14:50PM -0800, Andrii Nakryiko escreveu: > On Tue, Mar 9, 2021 at 1:57 PM Ilya Leoshkevich wrote: > > On Tue, 2021-03-09 at 13:37 -0800, Andrii Nakryiko wrote: > > > On Tue, Mar 9, 2021 at 3:48 AM Arnaldo Carvalho de Melo wrote: > > > > Em Tue, Mar 09, 2021 at 12:59:13AM +0100, Ilya Leoshkevich escreveu: > > > TBH, I think it's not exactly right to call out libbpf version > > > here. It's BTF "version" (if we had such a thing) that determines > > > the set of supported BTF kinds. There could be other libraries > > > that might want to parse BTF. So I don't know what this should be > > > called, but libbpf_compat is probably a wrong name for it. > > BTF version seems to exist: btf_header.version. Should we maybe bump > > this? > That seems excessive. If the kernel doesn't use FLOATs, then no one > would even notice a difference. While if we bump this version, then > everything will automatically become incompatible. > > > If we do want to teach pahole to not emit some parts of BTF, it > > > should > > > probably be a set of BPF features, not some arbitrary library > > > versions. > > I thought about just adding --btf-allow-floats, but if new features > > will be added in the future, the list of options will become unwieldy. > > So I thought it would be good to settle for something that increases > > monotonically. > BTF_KIND_FLOAT is the first extension in a long while. I'd worry about > the proliferation of new options when we actually see some proof of > that being a problem in practice. I tend to agree, Ilya, can you rework the patch in that direction? Something like --encode-btf-kind-float that starts disabled or other suitable name? - Arnaldo