From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754781Ab0LQRCA (ORCPT ); Fri, 17 Dec 2010 12:02:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64204 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754661Ab0LQRB6 (ORCPT ); Fri, 17 Dec 2010 12:01:58 -0500 Date: Fri, 17 Dec 2010 12:01:47 -0500 From: Vivek Goyal To: Yinghai 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 Message-ID: <20101217170146.GC9568@redhat.com> References: <20101209124117.GA6032@redhat.com> <4D01377B.5070809@kernel.org> <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3C6B7683-9CDC-4C4A-A32A-56227DE01387@kernel.org> 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 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. Thanks Vivek > Thanks > > On Dec 16, 2010, at 7:31 PM, "H. Peter Anvin" wrote: > > > On 12/15/2010 08:29 PM, Yinghai Lu wrote: > >> please check > >> > >> [PATCH] x86, crashkernel, 32bit: only try to get range under 512M > >> > >> Steanishlaw report kdump is 32bit is broken. > >> > >> in misc.c for decompresser, it will do sanity checking to make sure heap > >> heap under 512M. > >> > >> So limit it in first kernel under 512M for 32bit system. > >> > >> Reported-by: Stanislaw Gruszka > >> Signed-off-by: Yinghai Lu > >> > >> --- > >> arch/x86/kernel/setup.c | 14 +++++++++++++- > >> 1 file changed, 13 insertions(+), 1 deletion(-) > >> > > > > I'd like to apply a modified version of this patch (attached.) > > > > Ack/nak, people? > > > > -hpa > > <0001-x86-kexec-Limit-the-crashkernel-address-to-512-MiB.patch>