From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from terminus.zytor.com ([198.137.202.10]:41330 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751277AbcDTSFP (ORCPT ); Wed, 20 Apr 2016 14:05:15 -0400 In-Reply-To: <20160420134019.GX3448@twins.programming.kicks-ass.net> References: <1460041951-22347-1-git-send-email-mhocko@kernel.org> <1460041951-22347-11-git-send-email-mhocko@kernel.org> <20160413090829.GB29579@gmail.com> <20160413091625.GF14351@dhcp22.suse.cz> <20160413091943.GA17858@gmail.com> <20160413102731.GA29896@gmail.com> <20160413124943.GH14351@dhcp22.suse.cz> <20160420134019.GX3448@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Subject: Re: [PATCH 10/11] x86, rwsem: provide __down_write_killable From: "H. Peter Anvin" Date: Wed, 20 Apr 2016 11:04:05 -0700 Message-ID: <91A11395-ACAA-4043-B770-2DF6CBAED54C@zytor.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Peter Zijlstra , Michal Hocko Cc: Ingo Molnar , LKML , Ingo Molnar , Thomas Gleixner , "David S. Miller" , Tony Luck , Andrew Morton , Chris Zankel , Max Filippov , x86@kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-sh@vger.kernel.org, sparclinux@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org, Josh Poimboeuf Message-ID: <20160420180405.Ta7ZvAPz5T7BqTcpOF3Rxd3F-NyHAa0VuG_xpAf1IF8@z> On April 20, 2016 6:40:19 AM PDT, Peter Zijlstra wrote: >On Wed, Apr 13, 2016 at 02:49:43PM +0200, Michal Hocko wrote: >> On Wed 13-04-16 12:27:31, Ingo Molnar wrote: >> > >> > * Ingo Molnar wrote: >> > >> > > I'm testing your patches today, if they are otherwise OK [...] >> > >> > got this build failure: >> > >> > ./arch/x86/include/asm/rwsem.h:106:2: error: ‘asm’ operand has >impossible constraints >> >> Hmm, I have no idea why 64b didn't have problem with the asm but 32b >> complains. Anyway, the following makes both happy. I have checked the >> generated code for 64b and it hasn't changed after the patch. 32b >also >> seems to be generating a proper code. My gcc asm()-foo is rather weak >so >> I would feel better if somebody double checked after me. > >I completely blow at this gcc-asm constraints thing too :/ > >In any case, Ingo will you look after the rest of these patches, or do >you want me to pick up the remaining bits? The reason it breaks is because the same register can't be an input-output register and a separate input. However, the input side of the input-output is probably undefined, and so gcc may not notice. -- Sent from my Android device with K-9 Mail. Please excuse brevity and formatting.