From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mx1.redhat.com ([209.132.183.28]) by merlin.infradead.org with esmtp (Exim 4.80.1 #2 (Red Hat Linux)) id 1VZ0kQ-0001jh-LN for kexec@lists.infradead.org; Wed, 23 Oct 2013 15:53:27 +0000 Date: Wed, 23 Oct 2013 11:51:27 -0400 From: Vivek Goyal Subject: Re: [PATCH v4 0/3] x86, apic, kexec: Add disable_cpu_apic kernel parameter Message-ID: <20131023155127.GA17437@redhat.com> References: <20131022150015.24240.39686.stgit@localhost6.localdomain6> <20131022220803.GA32387@anatevka.fc.hp.com> <526712B2.7070108@jp.fujitsu.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <526712B2.7070108@jp.fujitsu.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=twosheds.infradead.org@lists.infradead.org To: HATAYAMA Daisuke Cc: fengguang.wu@intel.com, kexec@lists.infradead.org, linux-kernel@vger.kernel.org, jerry.hoemann@hp.com, bp@alien8.de, ebiederm@xmission.com, akpm@linux-foundation.org, hpa@linux.intel.com, jingbai.ma@hp.com On Wed, Oct 23, 2013 at 09:05:06AM +0900, HATAYAMA Daisuke wrote: [..] > >Do you literally mean a human at each boot will have to configure > >the kdump configuration files for passing disable_cpu_apic? > >Or do you envision the setting of disable_cpu_apic being put into > >the kdump initialization scripts? > > > >thanks > > > >Jerry > > Nearer to the former case, but this is not what a human should do. It's > a cumbersome task. I think, on fedora/RHEL system for example, kdump > service should check at each boot automatically. Hi Hatayama, So what information should I look for to prepare disable_cpu_apic=X in kdump script? Is BSP processor info exported to user space somewhere? Or assuming that processor 0 is BSP and corresponding apicid should be disabled in kdump kernel is good enough? I am looking at /proc/cpuinfo and following 3 fields seem interesting. processor: 0 apicid : 0 initial apicid : 0 What's the difference between apicid and "initial apicid". I guess initial apicid reflects the apicid number as set by firmware and then kernel can overwrite it and new number would be reflected in "apicid"? If that's the case, then I guess we should be looking at "apicid" of processor "0" and set that in disable_cpu_apic? Because that's the number kdump kernel boot should see in apic upon boot. Thanks Vivek _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec