Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965123AbVLVIDm (ORCPT ); Thu, 22 Dec 2005 03:03:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965124AbVLVIDm (ORCPT ); Thu, 22 Dec 2005 03:03:42 -0500 Received: from smtp103.plus.mail.mud.yahoo.com ([68.142.206.236]:27730 "HELO smtp103.plus.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S965123AbVLVIDl (ORCPT ); Thu, 22 Dec 2005 03:03:41 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=Udf2hm4gxayh3AsExt/8vNsQKeUG3OLyIoWerHTEwCWr6iaAxjfm0dXGsf05x8pbEKkR7S/4IJmJzGvV7rVlep7YJzd71D6TEW6/TCHz/EsCdjGaVAevhIX5N0Sg1OQfmTCs5a0J2WtpSELr+SezrfIqCmX4wF48h+slFJ2fYUQ= ; Message-ID: <43AA5DD4.1040606@yahoo.com.au> Date: Thu, 22 Dec 2005 19:03:32 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Nicolas Pitre CC: Ingo Molnar , Linus Torvalds , lkml , Andrew Morton , Arjan van de Ven , Jes Sorensen , Zwane Mwaikambo , Oleg Nesterov , David Howells , Alan Cox , Benjamin LaHaise , Steven Rostedt , Christoph Hellwig , Andi Kleen , Russell King Subject: Re: [patch 2/5] mutex subsystem: add architecture specific mutex primitives References: <20051221155411.GA7243@elte.hu> <20051221231218.GA6747@elte.hu> <43AA5978.1060705@yahoo.com.au> In-Reply-To: <43AA5978.1060705@yahoo.com.au> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 888 Lines: 23 Nick Piggin wrote: > I think ARMv6 has a decent atomic_cmpxchg implementation but does > not define __HAVE_ARCH_CMPXCHG. It might be useful to try to use this > for ARMv6 SMP for a slightly better trylock. > And on UP builds, it may simply be best to open code an interrupt unsafe cmpxchg and use atomic_cmpxchg unconditionally on SMP builds (which I think generates half decent code on all SMP architectures). Just something to think about. Of course this will require the dreaded preempt_disable() which might make it a showstopper. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com - 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/