From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750853AbWFGLrw (ORCPT ); Wed, 7 Jun 2006 07:47:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751152AbWFGLrw (ORCPT ); Wed, 7 Jun 2006 07:47:52 -0400 Received: from mail.ocs.com.au ([202.147.117.210]:5829 "EHLO mail.ocs.com.au") by vger.kernel.org with ESMTP id S1750853AbWFGLrw (ORCPT ); Wed, 7 Jun 2006 07:47:52 -0400 X-Mailer: exmh version 2.7.0 06/18/2004 with nmh-1.1-RC1 From: Keith Owens To: Andi Kleen cc: Ashok Raj , linux-kernel@vger.kernel.org, "Brendan Trotter" Subject: Re: NMI problems with Dell SMP Xeons In-reply-to: Your message of "Wed, 07 Jun 2006 10:01:40 +0200." <200606071001.40933.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Wed, 07 Jun 2006 21:47:40 +1000 Message-ID: <6799.1149680860@ocs3.ocs.com.au> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen (on Wed, 7 Jun 2006 10:01:40 +0200) wrote: > >> >> Two ways: >> >> (1) Boot with a kernel with CONFIG_ACPI=n, so the OS only finds 2 cpus >> in the MPT instead of the 4 listed by ACPI. >> >> (2) The kernel has ACPI=y, but is booted with maxcpus=2. >> >> In both cases, send_IPI_allbutself() with IPI 2 or an NMI will result >> in a hard reset. > >Sounds both like a "Don't do that when it hurts" . I know some people >have religious issues with ACPI, but it's simple a fact that many >modern boxes don't work correctly in obvious or subtle ways without it. Building a kernel without ACPI is silly nowadays. But even with ACPI, booting with a restricted maxcpus and sending IPI 2 or NMI as broadcast will kill these boxes. maxcpus is a valid option.