From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754007AbYEaEAA (ORCPT ); Sat, 31 May 2008 00:00:00 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750985AbYEaD7u (ORCPT ); Fri, 30 May 2008 23:59:50 -0400 Received: from smtp1.linux-foundation.org ([140.211.169.13]:45721 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750886AbYEaD7t (ORCPT ); Fri, 30 May 2008 23:59:49 -0400 Date: Fri, 30 May 2008 20:59:29 -0700 (PDT) From: Linus Torvalds To: Ulrich Drepper cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org, mtk.manpages@gmail.com Subject: Re: [PATCH 3/3] 64-bit futexes: x86 support In-Reply-To: <4840C394.2080807@redhat.com> Message-ID: References: <200805310127.m4V1RLdP013819@devserv.devel.redhat.com> <4840C394.2080807@redhat.com> User-Agent: Alpine 1.10 (LFD 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 30 May 2008, Ulrich Drepper wrote: > > In any case, robbing 64-bit architectures of the possible performance > gain just because there are ancient versions which cannot do it is just > plain stupid. I know you cannot suggest that. I'm suggesting that there are better approaches than forcing yet another new interface onto this thing. As mentioned, the kernel has had 32-bit rwsemaphores for a long time. Yes, there is "extra information" outside the 32-bit field, but I suspect you simply haven't looked hard enough at just using the existing futex code. You certainly didn't even read - or understand - my emails, since you thought I was talking about regular semaphores and ignored the "rw" part entirely (not to mention the fact that I talked about reader counts etc, which is why I think you didn't even read the email). Linus