Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932379AbWDAC5E (ORCPT ); Fri, 31 Mar 2006 21:57:04 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751485AbWDAC5D (ORCPT ); Fri, 31 Mar 2006 21:57:03 -0500 Received: from smtp107.mail.mud.yahoo.com ([209.191.85.217]:38491 "HELO smtp107.mail.mud.yahoo.com") by vger.kernel.org with SMTP id S1751483AbWDAC5B (ORCPT ); Fri, 31 Mar 2006 21:57:01 -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=4kpDbPT5/J2nmNX+Q1IznNpCLKlkGheCVnkEAwXqp8Wm7gm55Hr5SkFhlWzB1ansO/utxl9cKbIgDzXC53egga1hR+ysk9xcavmL2KnWiGylcnUqOm6HMhhP5yFjb7bg+WoKFizeqwQuh/uyttjjOozXgcdSaivK6+H07xKjH5M= ; Message-ID: <442DEBF7.1090806@yahoo.com.au> Date: Sat, 01 Apr 2006 12:56:55 +1000 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: Christoph Lameter CC: Zoltan Menyhart , "Boehm, Hans" , "Grundler, Grant G" , "Chen, Kenneth W" , akpm@osdl.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org Subject: Re: Synchronizing Bit operations V2 References: <442C7B51.1060203@yahoo.com.au> <442CAC11.4070803@yahoo.com.au> In-Reply-To: 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: 1538 Lines: 42 Christoph Lameter wrote: > On Fri, 31 Mar 2006, Nick Piggin wrote: >>You acknowledge that you have to fix ia64 to match current semantics >>first, right? > > > Right. I believe I have done so by making both smb_mb_* full barriers. All bitop and atomic test_and_set, inc_return, etc etc (ie. everything that modifies the operand and returns something) needs to be a full barrier before and after too. >>Now people seem to be worried about the performance impact that will >>have, so I simply suggest that adding two or three new macros for the >>important cases to give you a 90% solution. > > > We could transition some key locations of core code to use _mode bitops > if there are performance problems. > > >>I think Documentation/atomic_ops.txt isn't bad. smp_mb__* really >>is a smp_mb, which can be optimised sometimes. > > > Ok. Then we are on the same page and the solution I presented may be > acceptable. I have a new rev here that changes the naming a bit but I > think we are okay right? Not sure, to be honest. I think it is probably something which needs input from all the other arch people, and Linus, if you intend to use it to introduce new types of barriers. -- 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/