From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from d01relay04.pok.ibm.com (d01relay04.pok.ibm.com [9.56.227.236]) by e2.ny.us.ibm.com (8.12.11/8.12.11) with ESMTP id j5NMuQtE019842 for ; Thu, 23 Jun 2005 18:56:26 -0400 Received: from d01av04.pok.ibm.com (d01av04.pok.ibm.com [9.56.224.64]) by d01relay04.pok.ibm.com (8.12.10/NCO/VERS6.7) with ESMTP id j5NMuQKb223598 for ; Thu, 23 Jun 2005 18:56:26 -0400 Received: from d01av04.pok.ibm.com (loopback [127.0.0.1]) by d01av04.pok.ibm.com (8.12.11/8.13.3) with ESMTP id j5NMuQFS029415 for ; Thu, 23 Jun 2005 18:56:26 -0400 Subject: Re: sparsemem patches in -mm From: Dave Hansen In-Reply-To: <42BB3C26.6000603@linux-m68k.org> References: <20050621021352.46fc3b81.akpm@osdl.org> <42BB3C26.6000603@linux-m68k.org> Content-Type: text/plain Date: Thu, 23 Jun 2005 15:56:13 -0700 Message-Id: <1119567373.6694.15.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit To: Roman Zippel Cc: Andrew Morton , linux-arch@vger.kernel.org, Andy Whitcroft , Matt Tolentino , Bob Picco List-ID: On Fri, 2005-06-24 at 00:48 +0200, Roman Zippel wrote: > Andrew Morton wrote: > > Could I ask the arch maintainers to review the `sparsemem' patches from -mm, > > please, if you haven't done so... > > They would need a bit more work to be usable on m68k. I have a basic > patch to use DISCONTIGMEM for m68k. There I have the problem that I have > to deal with almost random memory configurations. So converting a > virtual/physical address or pfn into a section number can't use a > compile time constant, instead an offset/shift is calculated at boot > time and patched into the kernel. As far as the shift, you can simply use the smallest possible size as the SECTION_SIZE. Nothing I can think of with sparsemem requires you to have the kernel be at pfn 0. Unless you start at some completely huge address or have an exceedingly low SECTION_SIZE, everything should fit. Remember, sparsemem doesn't deal with virt/phys layout, just converting pfns to and from pages. If you want to mail me, or take this to your arch's list, we can probably discuss more of the specifics for your arch. -- Dave