From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Mon, 27 Jan 2003 17:02:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Mon, 27 Jan 2003 17:02:01 -0500 Received: from e34.co.us.ibm.com ([32.97.110.132]:40408 "EHLO e34.co.us.ibm.com") by vger.kernel.org with ESMTP id ; Mon, 27 Jan 2003 17:02:00 -0500 Date: Mon, 27 Jan 2003 14:03:24 -0800 From: "Martin J. Bligh" To: Dave Hansen , "Eric W. Biederman" cc: linux-kernel@vger.kernel.org Subject: Re: kexec reboot code buffer Message-ID: <203100000.1043705004@flay> In-Reply-To: <3E35AAE4.10204@us.ibm.com> References: <3E31AC58.2020802@us.ibm.com> <3E35AAE4.10204@us.ibm.com> X-Mailer: Mulberry/2.1.2 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org >> The problem is that I have not figured out how to tell the memory >> allocator just what I need, > >> I guess I would make the standard zones something like: >> /* >> * ZONE_DMA < 16 MB ISA DMA capable memory >> * ZONE_NORMAL 16-896 MB direct mapped by the kernel >> * ZONE_PHYSMEM 896-4096 MB memory that is accessible with the >> MMU disabled. >> * ZONE_HIGHMEM > 4096MB only page cache and user processes >> */ > > I think this might be overkill. ZONE_NORMAL gives you what you want, > and I don't think it's worth it to introduce a new one just for the > relatively short timespan where you have the new kernel loaded, but > haven't actually shut down. I think a little comment next to the > allocation explaining this will be more than enough. > > Martin, any ideas? We talked about creating a new zone specifically for DMA32 (ie <4Gb) for other reasons, but it's not there as yet. As Dave mentioned, ZONE_NORMAL should be sufficient, though if you need it physically contiguous, that might be a problem. How much memory do you need? If it's only 2Mb or so, why don't we statically reserve it at boot time and keep it set aside? M.