Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932490Ab2CAAnE (ORCPT ); Wed, 29 Feb 2012 19:43:04 -0500 Received: from mail-lpp01m010-f46.google.com ([209.85.215.46]:40966 "EHLO mail-lpp01m010-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932305Ab2CAAm6 (ORCPT ); Wed, 29 Feb 2012 19:42:58 -0500 Authentication-Results: mr.google.com; spf=pass (google.com: domain of bhelgaas@google.com designates 10.152.114.35 as permitted sender) smtp.mail=bhelgaas@google.com; dkim=pass header.i=bhelgaas@google.com MIME-Version: 1.0 In-Reply-To: References: <1330556858-11768-1-git-send-email-yinghai@kernel.org> <1330556858-11768-3-git-send-email-yinghai@kernel.org> From: Bjorn Helgaas Date: Wed, 29 Feb 2012 17:42:36 -0700 Message-ID: Subject: Re: [PATCH 02/39] x86, PCI: have own version for pcibios_bus_to_resource To: Yinghai Lu Cc: Jesse Barnes , Benjamin Herrenschmidt , Tony Luck , David Miller , x86 , Dominik Brodowski , linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org Content-Type: text/plain; charset=ISO-8859-1 X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1544 Lines: 38 On Wed, Feb 29, 2012 at 4:33 PM, Yinghai Lu wrote: > On Wed, Feb 29, 2012 at 3:20 PM, Bjorn Helgaas wrote: >> On Wed, Feb 29, 2012 at 4:07 PM, Yinghai Lu wrote: >>> x86 does not need to offset the address. So we can skip that costing offset >>> searching. >> >> I tried to start a discussion about this patch (and others), but I >> don't think you responded: >> http://marc.info/?l=linux-pci&m=133036414506921&w=2 > > this patch does reduce some not needed ops. > > and it does not affects your effects, It does affect my efforts in that this patch adds back x86 complexity that I don't think is necessary. And this patch makes it so the pci_add_resource_offset() interface exists and appears to work on x86, but if somebody tries to use it, it *doesn't* work. I don't like to write code like that. I think it's poor style. > and it just make x86 not get punished. What punishment are you worried about? I really don't think you'll be able to measure any performance impact. I agree that the x86 code you add *is* simpler than the generic version. But I think the *overall* complexity is higher because now you have to look at two versions (generic and x86) and convince yourself that it's safe to use the x86 version. Bjorn -- 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/