From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756621AbcHCB67 (ORCPT ); Tue, 2 Aug 2016 21:58:59 -0400 Received: from mx1.redhat.com ([209.132.183.28]:33562 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750954AbcHCB6s (ORCPT ); Tue, 2 Aug 2016 21:58:48 -0400 Date: Wed, 3 Aug 2016 09:58:18 +0800 From: Baoquan He To: Zhou Wenjian Cc: linux-kernel@vger.kernel.org, dyoung@redhat.com, d.hatayama@jp.fujitsu.com, kexec@lists.infradead.org Subject: Re: [PATCH v3 2/2] Documentation: kdump: add description of bringing up SMP dump-capture kernel Message-ID: <20160803015818.GB2465@x1.redhat.com> References: <1470185952-23477-1-git-send-email-zhouwj-fnst@cn.fujitsu.com> <1470185952-23477-2-git-send-email-zhouwj-fnst@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1470185952-23477-2-git-send-email-zhouwj-fnst@cn.fujitsu.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.29]); Wed, 03 Aug 2016 01:58:29 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/03/16 at 08:59am, Zhou Wenjian wrote: > SMP dump-capture kernel is useful to improve the performance of kdump in > some cases. So add the description of bringing up SMP dump-capture kernel. > > Signed-off-by: Zhou Wenjian > --- > Documentation/kdump/kdump.txt | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/Documentation/kdump/kdump.txt b/Documentation/kdump/kdump.txt > index 4aa194e..948b42d 100644 > --- a/Documentation/kdump/kdump.txt > +++ b/Documentation/kdump/kdump.txt > @@ -396,6 +396,13 @@ Notes on loading the dump-capture kernel: > Note, though maxcpus always works, we should replace it by nr_cpus to > save memory if supported by the current ARCH, such as x86. > > +* We should bring up a SMP dump-capture kernel if we intend to use Well, here about SMP dump-capture kernel do you mean kdump kernel with multi-cpu? If I understand it correctly, it's still SMP kdump kernel though nr_cpus=1 is specified. > + multi-threads programs with it, such as parallel dump feature of > + makedumpfile. Otherwise, the multi-threads program may have a great > + performance degradation. To bring up a SMP dump-capture kernel, we > + should specify maxcpus\nr_cpus and disable_cpu_apic=[X] options while > + loading it. > + > * For s390x there are two kdump modes: If a ELF header is specified with > the elfcorehdr= kernel parameter, it is used by the kdump kernel as it > is done on all other architectures. If no elfcorehdr= kernel parameter is > -- > 1.8.3.1 > > > > > _______________________________________________ > kexec mailing list > kexec@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/kexec