Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754606AbYJCIzu (ORCPT ); Fri, 3 Oct 2008 04:55:50 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752161AbYJCIzl (ORCPT ); Fri, 3 Oct 2008 04:55:41 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:44346 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751978AbYJCIzk (ORCPT ); Fri, 3 Oct 2008 04:55:40 -0400 Date: Fri, 3 Oct 2008 10:54:50 +0200 From: Ingo Molnar To: "Yu, Fenghua" Cc: Bjorn Helgaas , "Luck, Tony" , Jesse Barnes , David Woodhouse , Avi Kivity , Stephen Rothwell , Andrew Morton , LKML , "linux-ia64@vger.kernel.org" Subject: Re: [PATCH 1/2]Add Variable Page Size and IA64 Support in Intel IOMMU: Generic Part Message-ID: <20081003085450.GA27551@elte.hu> References: <617E1C2C70743745A92448908E030B2A02AD5AD7@scsmsx411.amr.corp.intel.com> <20081001165725.GA21559@linux-os.sc.intel.com> <20081002082942.GA26084@elte.hu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1029 Lines: 26 * Yu, Fenghua wrote: > >What's this all about? Why do we need #ifdef CONFIG_IA64 here? > >Doesn't x86 provide its own readq/writeq implementation? > > This is a comment from Bjorn. > > In my patch, one readq/one writeq are working faster than two > readl/two writel on IA64. X86 uses two readl/two writel so that the > code works on both x86 and x86-64 although Intel IOMMU only has x86-64 > version currently. dmar_readq() and dmar_writeq() are in moderate > performance critical path. > > Do you think my current implementation is ok to have #ifdef > CONFIG_IA64 here? Or I can change X86 to use readq/writeq as well or > IA64 uses two readl/two writel for clean code? yes, clean code is very much preferred for a small detail like this. Ingo -- 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/