Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592Ab0AZA7Y (ORCPT ); Mon, 25 Jan 2010 19:59:24 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752522Ab0AZA7T (ORCPT ); Mon, 25 Jan 2010 19:59:19 -0500 Received: from terminus.zytor.com ([198.137.202.10]:54922 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752331Ab0AZA7S (ORCPT ); Mon, 25 Jan 2010 19:59:18 -0500 Message-ID: <4B5E3E22.6030401@zytor.com> Date: Mon, 25 Jan 2010 16:58:10 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091209 Fedora/3.0-4.fc12 Thunderbird/3.0 MIME-Version: 1.0 To: Andrew Morton CC: Yinghai Lu , Christoph Lameter , Ingo Molnar , Thomas Gleixner , Jesse Barnes , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH 22/37] move round_up/down to kernel.h References: <1263611228-6751-1-git-send-email-yinghai@kernel.org> <1263611228-6751-23-git-send-email-yinghai@kernel.org> <4B57675E.7070309@kernel.org> <20100125164032.330be0e6.akpm@linux-foundation.org> In-Reply-To: <20100125164032.330be0e6.akpm@linux-foundation.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1378 Lines: 32 On 01/25/2010 04:40 PM, Andrew Morton wrote: > > The problem is that arch/x86/include/asm/proto.h implements private > rounding macros. The right way to fix that is to convert each x86 > "call site" over to using the standard macros from kernel.h, then > finally remove the private definitions from > arch/x86/include/asm/proto.h. Don't just copy them over to kernel.h > and make things muddier than they already are! > > If during that conversion it is found that the standard macros for some > reason don't suit the x86 usage sites then please propose > enhancements/fixes to the existing kernel.h facilities. > They don't. The kernel-global alignment macros assume that either the alignment datum (divisor) is a constant, or that it is acceptable to take the hit of a division. Unfortunately, we have real use cases where the alignment (guaranteed to be a power of two) is variable, but we don't want to take the hit of a full-blown division. I suspect the global kernel tree has those, too, but it would seem to be a dramatic change to change to change the existing facilities to assume power of two alignment... -hpa -- 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/