Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752235AbdHAWSX (ORCPT ); Tue, 1 Aug 2017 18:18:23 -0400 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:47270 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752022AbdHAWSW (ORCPT ); Tue, 1 Aug 2017 18:18:22 -0400 Date: Tue, 1 Aug 2017 15:18:18 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Will Deacon , Boqun Feng , linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , Randy Dunlap Subject: Re: [RFC][PATCH v3]: documentation,atomic: Add new documents Reply-To: paulmck@linux.vnet.ibm.com References: <20170726124750.vktrn5zi2gmpzfru@tardis> <20170731090535.rjgnoewqg7mhzr55@hirez.programming.kicks-ass.net> <20170731110403.ou3zqsp3uviqorkz@tardis> <20170731174345.GL3730@linux.vnet.ibm.com> <20170801090121.edo7mekhw3sann4h@hirez.programming.kicks-ass.net> <20170801101900.GB8702@arm.com> <20170801114744.evjjfviqhu5kgu7v@hirez.programming.kicks-ass.net> <20170801121713.GH8702@arm.com> <20170801161412.GW3730@linux.vnet.ibm.com> <20170801164200.oczql3m4f3zn6rin@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170801164200.oczql3m4f3zn6rin@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-GCONF: 00 x-cbid: 17080122-0052-0000-0000-00000248FD9B X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00007467; HX=3.00000241; KW=3.00000007; PH=3.00000004; SC=3.00000215; SDB=6.00896189; UDB=6.00448297; IPR=6.00676377; BA=6.00005506; NDR=6.00000001; ZLA=6.00000005; ZF=6.00000009; ZB=6.00000000; ZP=6.00000000; ZH=6.00000000; ZU=6.00000002; MB=3.00016486; XFM=3.00000015; UTC=2017-08-01 22:18:20 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 17080122-0053-0000-0000-0000518751A4 Message-Id: <20170801221818.GN3730@linux.vnet.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2017-08-01_13:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1706020000 definitions=main-1708010357 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 853 Lines: 22 On Tue, Aug 01, 2017 at 06:42:00PM +0200, Peter Zijlstra wrote: > On Tue, Aug 01, 2017 at 09:14:12AM -0700, Paul E. McKenney wrote: > > So if ARM really needs the litmus test with smp_rmb() to be allowed, > > we need to adjust the Linux-kernel memory model appropriately. Which > > means that one of us needs to reach out to the usual suspects. Would > > you like to do that, or would you like me to? > > I'm really sad ARM8.1 LSE breaks this stuff.. It is rather counter > intuitive (then again, we _are_ talking barriers). No argument. Then again, when we said that the Linux kernel memory model would have a non-trivial rate of change, we weren't joking. Will, is this the official description? http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ddi0557a.b/index.html If so, is B6.1 what we should be looking at? Thanx, Paul