From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751859Ab0JLWR1 (ORCPT ); Tue, 12 Oct 2010 18:17:27 -0400 Received: from mx1.redhat.com ([209.132.183.28]:20800 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751773Ab0JLWRY (ORCPT ); Tue, 12 Oct 2010 18:17:24 -0400 Date: Tue, 12 Oct 2010 18:17:17 -0400 From: Vivek Goyal To: "Eric W. Biederman" Cc: Alok Kataria , "kexec@lists.infradead.org" , Haren Myneni , the arch/x86 maintainers , LKML , Daniel Hecht , jeremy@xensource.com Subject: Re: [RFC PATCH] Bug during kexec...not all cpus are stopped Message-ID: <20101012221717.GA27478@redhat.com> References: <1286570087.8769.27.camel@ank32.eng.vmware.com> <1286816964.1372.2.camel@ank32.eng.vmware.com> <1286826083.1372.15.camel@ank32.eng.vmware.com> <20101011213901.GR12743@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 Mon, Oct 11, 2010 at 03:10:11PM -0700, Eric W. Biederman wrote: > Vivek Goyal writes: > > > On Mon, Oct 11, 2010 at 12:41:23PM -0700, Alok Kataria wrote: > > > I don't think that kdump path uses smp_send_stop(). > > It doesn't. > > > IIUC, on x86, we directly send NMI to other cpus. > > > > native_machine_crash_shutdown() > > kdump_nmi_shootdown_cpus() > > nmi_shootdown_cpus() > > smp_send_nmi_allbutself > > apic->send_IPI_allbutself(NMI_VECTOR); > > > > So above description should be limited to only panic() path. > > Is it actually confusing? With respect to documenting the line > of thinking it seems reasonable. > No, just wanted to point out that let us modify the changelog to remove keyword "kdump" from it. > > On a side note, I am wondering why panic() and kdump path can't share the > > shutdown routine. > > Hysterical raisins. Andi's change to smp_send_stop says that NMIs not > working on some boxes. When someone wants to weed through all of the > insanity it would probably be good to get the panic and the kdump paths > sharing code. For now simply separating panic and reboot should be > enough, and it lets the code evolve where it needs to. > Ok. Agreed that atleast conceptually kdump and panic() path should share the code. But that's a different problem altogether and this patch can go in. Thanks Vivek