Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752709AbWKBWlf (ORCPT ); Thu, 2 Nov 2006 17:41:35 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752712AbWKBWlf (ORCPT ); Thu, 2 Nov 2006 17:41:35 -0500 Received: from calculon.skynet.ie ([193.1.99.88]:47286 "EHLO calculon.skynet.ie") by vger.kernel.org with ESMTP id S1752709AbWKBWle (ORCPT ); Thu, 2 Nov 2006 17:41:34 -0500 Date: Thu, 2 Nov 2006 22:41:32 +0000 (GMT) From: Mel Gorman X-X-Sender: mel@skynet.skynet.ie To: Magnus Damm Cc: Magnus Damm , linux-kernel@vger.kernel.org, Vivek Goyal , Andi Kleen , fastboot@lists.osdl.org Subject: Re: [PATCH] x86_64: setup saved_max_pfn correctly (kdump) In-Reply-To: Message-ID: References: <20061102131934.24684.93195.sendpatchset@localhost> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2132 Lines: 65 On Fri, 3 Nov 2006, Magnus Damm wrote: > Hi Mel, > > Thanks for your input! Great work with the add_active_range() code. > Thanks > On 11/3/06, Mel Gorman wrote: >> Hey Magnus, >> >> I see what you are doing and why. However if you look in >> arch/x86_64/kernel/setup.c, you'll see >> >> parse_early_param(); >> >> finish_e820_parsing(); >> >> e820_register_active_regions(0, 0, -1UL); >> >> If you just called e820_register_active_regions(0, 0, -1UL) before >> parse_early_param(), would it still fix the problem without having to call >> e820_register_active_regions(0, 0, -1UL) twice? > > Well, I guess it is possible to move the > e820_register_active_regions() up, but I'm not sure if that would give > us anything. > > We need to call e820_register_active_regions() before e820_end_of_ram, > that's for sure, but the "exactmap" code in parse_memmap_opt() sets > e820.nr_map to 0 after the call to e820_end_of_ram(). Then it adds a > new set of user-supplied ranges to the e820 map which then need to be > registered using e820_register_active_regions(). > > So yeah, we can move the function up above parse_early_param() but > then we need to insert another call to e820_register_active_regions() > somewhere after all user-supplied ranges have been added. > Ah right, I see the problem now and why you need to do things that way in your patch. Sorry about that. > Another solution could be to rewrite e820_end_of_ram() to instead scan > e820.map[] backwards from e820.nr_map - 1 to locate the last ram page. > But can you do that in two lines of code? =) > Nope. As the path you are doing this in is not time-critical, the patch is fine to me. > Thanks! > > / magnus > -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab - 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/