From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761591Ab3DDOQR (ORCPT ); Thu, 4 Apr 2013 10:16:17 -0400 Received: from mx1.redhat.com ([209.132.183.28]:5329 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760960Ab3DDOQQ (ORCPT ); Thu, 4 Apr 2013 10:16:16 -0400 Date: Thu, 4 Apr 2013 10:16:04 -0400 From: Vivek Goyal To: Yinghai Lu Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , WANG Chao , "Eric W. Biederman" , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 2/4] x86, kdump: Retore crashkernel= to allocate low Message-ID: <20130404141604.GD16459@redhat.com> References: <1365035906-3208-1-git-send-email-yinghai@kernel.org> <1365035906-3208-4-git-send-email-yinghai@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1365035906-3208-4-git-send-email-yinghai@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 Wed, Apr 03, 2013 at 05:38:25PM -0700, Yinghai Lu wrote: > Vivek found old kexec-tools does not work new kernel anymore. > > So change back crashkernel= back to old behavoir, and add crashkernel_high= > to let user decide if buffer could be above 4G, and also new kexec-tools will > be needed. > > v2: let crashkernel=X override crashkernel_high= > update description about _high will be ignored by crashkernel=X > > Signed-off-by: Yinghai Lu > > --- > Documentation/kernel-parameters.txt | 11 +++++++++-- > arch/x86/kernel/setup.c | 24 +++++++++++++++++++----- > include/linux/kexec.h | 2 ++ > kernel/kexec.c | 9 +++++++++ > 4 files changed, 39 insertions(+), 7 deletions(-) > > Index: linux-2.6/Documentation/kernel-parameters.txt > =================================================================== > --- linux-2.6.orig/Documentation/kernel-parameters.txt > +++ linux-2.6/Documentation/kernel-parameters.txt > @@ -603,9 +603,14 @@ bytes respectively. Such letter suffixes > a memory unit (amount[KMG]). See also > Documentation/kdump/kdump.txt for an example. > > + crashkernel_high=size[KMG] > + [KNL, x86_64] range could be above 4G. Allow kernel > + to allocate physical memory region from top, so could > + be above 4G if system have more than 4G ram installed. Also specify "otherwise memory will be allocated below 4G, if available". > + It will be ignored if crashkernel=X is specified. > crashkernel_low=size[KMG] > - [KNL, x86_64] range under 4G. When crashkernel= is > - passed, kernel allocate physical memory region > + [KNL, x86_64] range under 4G. When crashkernel_high= is > + passed, kernel could allocate physical memory region > above 4G, that cause second kernel crash on system > that need swiotlb later. Kernel would try to allocate > some region below 4G automatically. This one let > @@ -614,6 +619,8 @@ bytes respectively. Such letter suffixes > 0: to disable low allocation on systems that do not > need swiotlb, that will save 72M low ram in first > kernel. > + It will be ignored when crashkernel_high=X is not used > + or return from that is below 4G. Replace "return from that" with "memory reserved". Vivek