Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964908Ab3DPKFc (ORCPT ); Tue, 16 Apr 2013 06:05:32 -0400 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:48157 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964853Ab3DPKFa (ORCPT ); Tue, 16 Apr 2013 06:05:30 -0400 Date: Tue, 16 Apr 2013 11:05:05 +0100 From: Will Deacon To: Waiman Long Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "Paul E. McKenney" , David Howells , Dave Jones , Clark Williams , Peter Zijlstra , "linux-kernel@vger.kernel.org" , "x86@kernel.org" , "linux-arch@vger.kernel.org" , "Chandramouleeswaran, Aswin" , Davidlohr Bueso , "Norton, Scott J" , Rik van Riel Subject: Re: [PATCH v2 optional 3/3] mutex: back out architecture specific check for negative mutex count Message-ID: <20130416100505.GD31156@mudshark.cambridge.arm.com> References: <1366036679-9702-1-git-send-email-Waiman.Long@hp.com> <1366036679-9702-4-git-send-email-Waiman.Long@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1366036679-9702-4-git-send-email-Waiman.Long@hp.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 865 Lines: 19 On Mon, Apr 15, 2013 at 03:37:59PM +0100, Waiman Long wrote: > If it is confirmed that all the supported architectures can allow a > negative mutex count without incorrect behavior, we can then back > out the architecture specific change and allow the mutex count to > go to any negative number. That should further reduce contention for > non-x86 architecture. > > If this is not the case, this patch should be dropped. A good starting point might be to look at the asm-generic mutex implementations, which clears up the majority of architectures. A cursory glance at mutex-dec.h suggests that it's OK to me... Will -- 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/