Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752202AbaFFPP1 (ORCPT ); Fri, 6 Jun 2014 11:15:27 -0400 Received: from e35.co.us.ibm.com ([32.97.110.153]:56053 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751646AbaFFPPY (ORCPT ); Fri, 6 Jun 2014 11:15:24 -0400 Date: Fri, 6 Jun 2014 08:15:18 -0700 From: "Paul E. McKenney" To: Peter Zijlstra Cc: Linus Torvalds , Mikulas Patocka , "James E.J. Bottomley" , Helge Deller , John David Anglin , Parisc List , Linux Kernel Mailing List , "Vinod, Chegu" , Waiman Long , Thomas Gleixner , Rik van Riel , Andrew Morton , Davidlohr Bueso , Peter Anvin , Andi Kleen , "Chandramouleeswaran, Aswin" , "Norton, Scott J" , Jason Low , mingo@kernel.org Subject: Re: [PATCH v2] introduce atomic_pointer to fix a race condition in cancelable mcs spinlocks Message-ID: <20140606151518.GI4581@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com References: <20140602162525.GH16155@laptop.programming.kicks-ass.net> <20140606150607.GT13930@laptop.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140606150607.GT13930@laptop.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14060615-6688-0000-0000-000002631B87 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 06, 2014 at 05:06:07PM +0200, Peter Zijlstra wrote: > On Mon, Jun 02, 2014 at 10:09:35AM -0700, Linus Torvalds wrote: > > On Mon, Jun 2, 2014 at 9:25 AM, Peter Zijlstra wrote: > > > > > > And I can't say I'm a particular fan of these ops either, as alternative > > > I'm almost inclined to just exclude parisc from using opt spinning. > > > > Please do. > > Something like so; if the rwsem stuff lands in .15 we need more for > that, it doesn't have a convenient CONFIG symbol like this. > > Linus will you take this from email, or should I get it through > tip/locking/urgent or so? > > --- > Subject: locking, mutex: Disable optimistic spinning for PA-RISC > > PA-RISC's cmpxchg is not save against normal stores and the code used > for optimistic spinning is known broken because of this. > > Disable for now. > > Reported-by: Mikulas Patocka > Signed-off-by: Peter Zijlstra Reviewed-by: Paul E. McKenney > --- > kernel/Kconfig.locks | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/kernel/Kconfig.locks b/kernel/Kconfig.locks > index 35536d9c0964..9c239e080c2d 100644 > --- a/kernel/Kconfig.locks > +++ b/kernel/Kconfig.locks > @@ -222,7 +222,7 @@ endif > > config MUTEX_SPIN_ON_OWNER > def_bool y > - depends on SMP && !DEBUG_MUTEXES > + depends on SMP && !DEBUG_MUTEXES && !PARISC > > config ARCH_USE_QUEUE_RWLOCK > bool > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/