From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754766AbaBTRzn (ORCPT ); Thu, 20 Feb 2014 12:55:43 -0500 Received: from mx1.redhat.com ([209.132.183.28]:3250 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751882AbaBTRzl (ORCPT ); Thu, 20 Feb 2014 12:55:41 -0500 Subject: Re: [RFC][PATCH 0/5] arch: atomic rework From: Torvald Riegel To: paulmck@linux.vnet.ibm.com Cc: Linus Torvalds , Will Deacon , Peter Zijlstra , Ramana Radhakrishnan , David Howells , "linux-arch@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "akpm@linux-foundation.org" , "mingo@kernel.org" , "gcc@gcc.gnu.org" In-Reply-To: <20140220083032.GN4250@linux.vnet.ibm.com> References: <20140218030002.GA15857@linux.vnet.ibm.com> <1392740258.18779.7732.camel@triegel.csb> <1392752867.18779.8120.camel@triegel.csb> <20140220040102.GM4250@linux.vnet.ibm.com> <20140220083032.GN4250@linux.vnet.ibm.com> Content-Type: text/plain; charset="UTF-8" Date: Thu, 20 Feb 2014 18:54:06 +0100 Message-ID: <1392918846.18779.10204.camel@triegel.csb> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2014-02-20 at 00:30 -0800, Paul E. McKenney wrote: > Well, all the compilers currently convert consume to acquire, so you have > your wish there. Of course, that also means that they generate actual > unneeded memory-barrier instructions, which seems extremely sub-optimal > to me. GCC doesn't currently, but it also doesn't seem to track the dependencies, but that's a bug: http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59448