Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755587Ab0LQS12 (ORCPT ); Fri, 17 Dec 2010 13:27:28 -0500 Received: from rcsinet10.oracle.com ([148.87.113.121]:57909 "EHLO rcsinet10.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754753Ab0LQS11 (ORCPT ); Fri, 17 Dec 2010 13:27:27 -0500 Message-ID: <4D0BAA24.3080801@kernel.org> Date: Fri, 17 Dec 2010 10:21:24 -0800 From: Yinghai Lu User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20101125 SUSE/3.0.11 Thunderbird/3.0.11 MIME-Version: 1.0 To: Vivek Goyal CC: "H. Peter Anvin" , Stanislaw Gruszka , Ingo Molnar , Thomas Gleixner , Maxim Uvarov , "linux-kernel@vger.kernel.org" , Neil Horman Subject: Re: kdump broken on 2.6.37-rc4 References: <20101213100848.GA2237@redhat.com> <4D0663F0.2060103@kernel.org> <4D06783C.6040009@zytor.com> <20101214224135.GB19693@redhat.com> <20101215103954.GA2243@redhat.com> <4D09958D.2040907@kernel.org> <4D0AD976.3020504@zytor.com> <3C6B7683-9CDC-4C4A-A32A-56227DE01387@kernel.org> <20101217170146.GC9568@redhat.com> <4D0BA45A.7020402@zytor.com> <20101217180242.GB12425@redhat.com> In-Reply-To: <20101217180242.GB12425@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1817 Lines: 45 On 12/17/2010 10:02 AM, Vivek Goyal wrote: > On Fri, Dec 17, 2010 at 09:56:42AM -0800, H. Peter Anvin wrote: >> On 12/17/2010 09:01 AM, Vivek Goyal wrote: >>> On Thu, Dec 16, 2010 at 07:58:48PM -0800, Yinghai wrote: >>>> Please don't do that to 64 bit >>>> >>>> My big system with 1024g memory and a lot of cards with rhel 6 to make kdump work must have crashkernel=512m and second kernel need to take pci=nomsi >>>> >>> >>> I agree here that we should not do it for 64 bit. >>> >>> - Just because we need it for 32 bit does not mean we should limit it for >>> 64bit. And we do want to have the capability to boot the kernel from as >>> high memory as possible so creating another aritificial limit is counter >>> to that. >>> >>> - I would not worry too much about backward compatibility and allow >>> booting 32bit kernel till 768MB. The reason being that most of the >>> distros use same kernel for crash dumping as regular kernel. Maintainig >>> two separate kernels is big hassle. >>> >>> So a small set of people who run into issue, would need to change kernel >>> command line "crashkernel=128M@64M" or something similar. >>> >> >> 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. or crashkernel=... will take two ranges like one high and one low. also kexec bzImage in 64bit should use startup_64 aka 0x200 offset instead of startup_32 in arch/x86/boot/compressed/head_64.S then bzImage can be put above 4G... Thanks Yinghai -- 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/