From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751591AbdALDXO (ORCPT ); Wed, 11 Jan 2017 22:23:14 -0500 Received: from mx1.redhat.com ([209.132.183.28]:42856 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750880AbdALDXM (ORCPT ); Wed, 11 Jan 2017 22:23:12 -0500 Reply-To: xlpang@redhat.com Subject: Re: [PATCH] Add +~800M crashkernel explaination References: <20161210002202.19829-1-robert@leblancnet.us> <20161210024927.GD1034@x1> <5850B791.4040209@redhat.com> <5851D2F6.4020009@redhat.com> To: Robert LeBlanc , xlpang@redhat.com Cc: kexec@lists.infradead.org, "Linux-Kernel@Vger. Kernel. Org" , Baoquan He , linux-doc@vger.kernel.org From: Xunlei Pang Message-ID: <5876F6E1.4050001@redhat.com> Date: Thu, 12 Jan 2017 11:24:17 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Thu, 12 Jan 2017 03:22:28 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/12/2017 at 03:35 AM, Robert LeBlanc wrote: > On Wed, Dec 14, 2016 at 4:17 PM, Xunlei Pang wrote: >> As I replied in another post, if you really want to detail the behaviour, should mention >> "crashkernel=size[KMG][@offset[KMG]]" with @offset[KMG] specified explicitly, after >> all, it's handled differently with no upper bound limitation, but doing this may put >> the first kernel at the risk of lacking low memory(some devices require 32bit DMA), >> must use it with care because the kernel will assume users are aware of what they >> are doing and make a successful reservation as long as the given range is available. > crashkernel=1024M@0x10000000 > > I can't get the offset to work. It seems that it allocates the space > and loads the crash kernel, but I couldn't get it to actually boot > into the crash kernel. Does it work for you? I'm using the 4.9 kernel. Not sure what is the problem you met, but kdump kernel boots well using 4.9 on my x86_64 machine. Regards, Xunlei