From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from westrelay02.boulder.ibm.com (westrelay02.boulder.ibm.com [9.17.195.11]) by e33.co.us.ibm.com (8.13.8/8.12.11) with ESMTP id k7SHMvI7004687 for ; Mon, 28 Aug 2006 13:22:57 -0400 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by westrelay02.boulder.ibm.com (8.13.6/8.13.6/NCO v8.1.1) with ESMTP id k7SHMvQR334404 for ; Mon, 28 Aug 2006 11:22:57 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id k7SHMvHZ017367 for ; Mon, 28 Aug 2006 11:22:57 -0600 Subject: Re: [RFC][PATCH 2/7] ia64 generic PAGE_SIZE From: Dave Hansen In-Reply-To: References: <20060828154413.E05721BD@localhost.localdomain> <20060828154414.38AEDAA2@localhost.localdomain> Content-Type: text/plain Date: Mon, 28 Aug 2006 10:22:53 -0700 Message-Id: <1156785773.5913.38.camel@localhost.localdomain> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: linux-mm@kvack.org List-ID: On Mon, 2006-08-28 at 10:04 -0700, Christoph Lameter wrote: > On Mon, 28 Aug 2006, Dave Hansen wrote: > > -config IA64_PAGE_SIZE_64KB > > - depends on !ITANIUM > > - bool "64KB" > > - > > -endchoice > > Uhh.. arch specific stuff in mm/Kconfig. Each arch needs to modify the > mm/Kconfig? Yes and no. First of all, 15 of the 24 architectures use the Kconfig default of 4k pages. Anybody adding an architecture with 4k pages only has to include asm-generic/page.h in their arch, and they don't add *anything* to Kconfig. If they want completely fixed page sizes other than 4k, they only add '|| ARCH' on one line in the Kconfig. There are a couple of ways to go about enabling the configurable page sizes. One is to do what I did, hand have all of the architectures enumerated in mm/Kconfig. The other is to have something along the lines of: choice prompt "Kernel Page Size" depends on ARCH_CHOOSES_PAGE_SIZE ... Then in arch/{ia64,...}/Kconfig, have config ARCH_CHOOSES_PAGE_SIZE def_bool y That would be easy enough to do. However, what I wanted to get out of this was to be able to look at mm/Kconfig and get a really nice overview of what *everybody* is doing. I'd be more inclined to do the ARCH_CHOOSES... stuff if the architecture-specific conditions were actually complicated. They really aren't. Admittedly, this is a bit different from how it has been done traditionally, but is is a really great tool for anyone working on arch-generic code that wants to know "what architectures have an 8k page size", or "what arches have a configurable page size". This makes one place to go look, with zero grepping. > Also cc linux-ia64@vger.kernel.org on these. Sure thing. -- Dave -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org