Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756008Ab0LQUL3 (ORCPT ); Fri, 17 Dec 2010 15:11:29 -0500 Received: from mx1.redhat.com ([209.132.183.28]:47787 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755653Ab0LQUL2 (ORCPT ); Fri, 17 Dec 2010 15:11:28 -0500 Date: Fri, 17 Dec 2010 15:11:04 -0500 From: Vivek Goyal To: "H. Peter Anvin" Cc: Yinghai Lu , Stanislaw Gruszka , Ingo Molnar , Thomas Gleixner , Maxim Uvarov , "linux-kernel@vger.kernel.org" , Neil Horman Subject: Re: kdump broken on 2.6.37-rc4 Message-ID: <20101217201104.GG14502@redhat.com> References: <4D0AD976.3020504@zytor.com> <3C6B7683-9CDC-4C4A-A32A-56227DE01387@kernel.org> <20101217170146.GC9568@redhat.com> <4D0BA45A.7020402@zytor.com> <20101217180242.GB12425@redhat.com> <4D0BAA24.3080801@kernel.org> <4D0BBC55.4010207@zytor.com> <4D0BBE00.3010602@kernel.org> <20101217195035.GE14502@redhat.com> <4D0BC067.90507@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4D0BC067.90507@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 48 On Fri, Dec 17, 2010 at 11:56:23AM -0800, H. Peter Anvin wrote: > On 12/17/2010 11:50 AM, Vivek Goyal wrote: > > On Fri, Dec 17, 2010 at 11:46:08AM -0800, Yinghai Lu wrote: > >> On 12/17/2010 11:39 AM, H. Peter Anvin wrote: > >>> On 12/17/2010 10:21 AM, Yinghai Lu wrote: > >>>>>> > >>>>>> Do we have actual testing for how high the 64-bit kernel will load? > >>>>> > >>>>> I will do some experiments on my box today and let you know. > >>>> > >>>> if bzImage is used, it is 896M. > >>>> > >>> > >>> Why? 896 MiB is a 32-bit kernel limitation which doesn't have anything > >>> to do with the bzImage format. > >>> > >>> So unless there is something going on here, I suspect you're just plain > >>> flat wrong. > >> > >> kexec-tools have some checking when it loads bzImage. > >> > > > > Yinghai, > > > > I think x86_64 might have just inherited the settings of 32bit without > > giving it too much of thought. At that point of time nobody bothered > > to load the kernel from high addresses. So these might be artificial > > limits. > > > > Can we do this in the meantime, just so we fix the immediate problem? Peter, kexec-tools on 64bit currently seems to be allowing loding bzImage till 896MB. So I am not too keen it to reduce it to 768MB in kernel just because x86_64 could be booted from even higher addresses and somebody first has to do some auditing and experiments. IMHO, we should have 768MB limit for 32bit and continue with 896MB limit for 64bit and once somebody makes x86_64 boot from even higher address reliably then we can change both kernel and kexec-tools. Thanks Vivek -- 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/