From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: [PATCH v5 4/4] qrwlock: Use the mcs_spinlock helper functions for MCS queuing Date: Fri, 8 Nov 2013 19:07:18 -0800 Message-ID: <20131109030718.GN18245@linux.vnet.ibm.com> References: <1383585440-4391-1-git-send-email-Waiman.Long@hp.com> <1383585440-4391-5-git-send-email-Waiman.Long@hp.com> <20131108212107.GI18245@linux.vnet.ibm.com> <1383959827.11046.420.camel@schen9-DESK> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from e33.co.us.ibm.com ([32.97.110.151]:37305 "EHLO e33.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758078Ab3KIDH0 (ORCPT ); Fri, 8 Nov 2013 22:07:26 -0500 Received: from /spool/local by e33.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 8 Nov 2013 20:07:26 -0700 Content-Disposition: inline In-Reply-To: <1383959827.11046.420.camel@schen9-DESK> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Tim Chen Cc: Waiman Long , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Arnd Bergmann , linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Steven Rostedt , Andrew Morton , Michel Lespinasse , Andi Kleen , Rik van Riel , Linus Torvalds , Raghavendra K T , George Spelvin , "Aswin Chandramouleeswaran\"" , Scott J Norton On Fri, Nov 08, 2013 at 05:17:07PM -0800, Tim Chen wrote: > On Fri, 2013-11-08 at 13:21 -0800, Paul E. McKenney wrote: > > On Mon, Nov 04, 2013 at 12:17:20PM -0500, Waiman Long wrote: > > > There is a pending patch in the rwsem patch series that adds a generic > > > MCS locking helper functions to do MCS-style locking. This patch > > > will enable the queue rwlock to use that generic MCS lock/unlock > > > primitives for internal queuing. This patch should only be merged > > > after the merging of that generic MCS locking patch. > > > > > > Signed-off-by: Waiman Long > > > > This one does might address at least some of the earlier memory-barrier > > issues, at least assuming that the MCS lock is properly memory-barriered. > > Paul, will appreciate if you can take a look the latest version > of MCS lock with load-acquire and store-release to see if it is now > properly memory-barriered. Don't worry, you cannot escape. It is on my list. ;-) Thanx, Paul