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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 CD5F3C64EB8 for ; Thu, 4 Oct 2018 08:40:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 976C521473 for ; Thu, 4 Oct 2018 08:40:38 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 976C521473 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727524AbeJDPcq convert rfc822-to-8bit (ORCPT ); Thu, 4 Oct 2018 11:32:46 -0400 Received: from terminus.zytor.com ([198.137.202.136]:54133 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726857AbeJDPcq (ORCPT ); Thu, 4 Oct 2018 11:32:46 -0400 Received: from wld62.hos.anvin.org (c-24-5-245-234.hsd1.ca.comcast.net [24.5.245.234] (may be forged)) (authenticated bits=0) by mail.zytor.com (8.15.2/8.15.2) with ESMTPSA id w948eQ8f2678722 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NO); Thu, 4 Oct 2018 01:40:27 -0700 Date: Thu, 04 Oct 2018 01:40:20 -0700 User-Agent: K-9 Mail for Android In-Reply-To: <20181004083333.GA9802@gmail.com> References: <20181003213100.189959-1-namit@vmware.com> <20181003213100.189959-5-namit@vmware.com> <20181004075755.GA3353@gmail.com> <20181004083333.GA9802@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Subject: Re: [PATCH v9 04/10] x86: refcount: prevent gcc distortions To: Ingo Molnar , Nadav Amit CC: Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Jan Beulich , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Andy Lutomirski From: hpa@zytor.com Message-ID: <10D29A50-C352-4407-A824-0C3C06CD8592@zytor.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On October 4, 2018 1:33:33 AM PDT, Ingo Molnar wrote: > >* Ingo Molnar wrote: > >> I'm also somewhat annoyed at the fact that this series carries a >boatload >> of reviewed-by's and acked-by's, yet none of those reviewers found it >> important to point out the large chasm that is gaping between >description >> and reality. > >Another problem I just realized is that we now include >arch/x86/kernel/macros.S in every >translation pass when building the kernel, right? > >But arch/x86/kernel/macros.S expands to a pretty large hiearchy of >header files: > > $ make arch/x86/kernel/macros.s > >$ cat $(grep include arch/x86/kernel/macros.s | cut -d\" -f2 | sort | >uniq) | wc -l > 4128 > >That's 4,100 extra lines of code to be preprocessed for every >translation unit, of >which there are tens of thousands. More if other pieces of code get >macrofied in >this fasion in the future. > >If we assume that a typical distribution kernel build has ~20,000 >translation units >then this change adds 82,560,000 more lines to be preprocessed, just to >work around >a stupid GCC bug? > >I'm totally unhappy about that. Can we do this without adding macros.S? > >It's also a pretty stupidly central file anyway that moves source code >away >from where it's used. > >Thanks, > > Ingo It's not just for working around a stupid GCC bug, but it also has a huge potential for cleaning up the inline asm in general. I would like to know if there is an actual number for the build overhead (an actual benchmark); I have asked for that once already. -- Sent from my Android device with K-9 Mail. Please excuse my brevity.