From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754742AbbKLOua (ORCPT ); Thu, 12 Nov 2015 09:50:30 -0500 Received: from bombadil.infradead.org ([198.137.202.9]:37725 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753364AbbKLOu0 (ORCPT ); Thu, 12 Nov 2015 09:50:26 -0500 Date: Thu, 12 Nov 2015 15:50:13 +0100 From: Peter Zijlstra To: "Paul E. McKenney" Cc: Oleg Nesterov , Boqun Feng , mingo@kernel.org, linux-kernel@vger.kernel.org, corbet@lwn.net, mhocko@kernel.org, dhowells@redhat.com, torvalds@linux-foundation.org, will.deacon@arm.com, Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras Subject: Re: [PATCH 4/4] locking: Introduce smp_cond_acquire() Message-ID: <20151112145013.GB17308@twins.programming.kicks-ass.net> References: <20151102132901.157178466@infradead.org> <20151102134941.005198372@infradead.org> <20151103175958.GA4800@redhat.com> <20151111093939.GA6314@fixme-laptop.cn.ibm.com> <20151111121232.GN17308@twins.programming.kicks-ass.net> <20151111193953.GA23515@redhat.com> <20151112070915.GC6314@fixme-laptop.cn.ibm.com> <20151112150058.GA30321@redhat.com> <20151112144004.GU3972@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20151112144004.GU3972@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 12, 2015 at 06:40:04AM -0800, Paul E. McKenney wrote: > I cannot resist suggesting that any lock that interacts with > spin_unlock_wait() must have all relevant acquisitions followed by > smp_mb__after_unlock_lock(). Ha! that would certainly help here. But it would mean that argh64v8 also needs to define that, even though that is already RCsc.