Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267770AbUIUPpy (ORCPT ); Tue, 21 Sep 2004 11:45:54 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267772AbUIUPpy (ORCPT ); Tue, 21 Sep 2004 11:45:54 -0400 Received: from cantor.suse.de ([195.135.220.2]:14056 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S267770AbUIUPpt (ORCPT ); Tue, 21 Sep 2004 11:45:49 -0400 Date: Tue, 21 Sep 2004 17:45:42 +0200 From: Andi Kleen To: Denis Vlasenko Cc: Andi Kleen , Christoph Lameter , akpm@osdl.org, "David S. Miller" , benh@kernel.crashing.org, wli@holomorphy.com, davem@redhat.com, raybry@sgi.com, ak@muc.de, manfred@colorfullife.com, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, vrajesh@umich.edu, hugh@veritas.com Subject: Re: page fault scalability patch V8: [4/7] universally available cmpxchg on i386 Message-ID: <20040921154542.GB12132@wotan.suse.de> References: <20040920205752.GH4242@wotan.suse.de> <200409211841.25507.vda@port.imtp.ilyichevsk.odessa.ua> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200409211841.25507.vda@port.imtp.ilyichevsk.odessa.ua> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1139 Lines: 27 On Tue, Sep 21, 2004 at 06:41:25PM +0300, Denis Vlasenko wrote: > On Monday 20 September 2004 23:57, Andi Kleen wrote: > > On Mon, Sep 20, 2004 at 01:49:20PM -0700, Christoph Lameter wrote: > > > On Mon, 20 Sep 2004, Denis Vlasenko wrote: > > > > > > > I think it shouldn't be this way. > > > > > > > > OTOH for !CONFIG_386 case it makes perfect sense to have it inlined. > > > > > > Would the following revised patch be acceptable? > > > > You would need an EXPORT_SYMBOL at least. But to be honest your > > original patch was much simpler and nicer and cmpxchg is not called > > that often that it really matters. I would just ignore Denis' > > suggestion and stay with the old patch. > > A bit faster approach (for CONFIG_386 case) would be using It's actually slower. Many x86 CPUs cannot predict indirect jumps and those that do cannot predict them as well as a test and jump. -Andi - 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/