From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754283AbWKMIRN (ORCPT ); Mon, 13 Nov 2006 03:17:13 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754284AbWKMIRN (ORCPT ); Mon, 13 Nov 2006 03:17:13 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:8394 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1754227AbWKMIRM (ORCPT ); Mon, 13 Nov 2006 03:17:12 -0500 Date: Mon, 13 Nov 2006 09:16:16 +0100 From: Ingo Molnar To: Andi Kleen Cc: "Siddha, Suresh B" , Andrew Morton , linux-kernel@vger.kernel.org, ashok.raj@intel.com Subject: Re: [patch] genapic: optimize & fix APIC mode setup Message-ID: <20061113081616.GA25604@elte.hu> References: <20061111151414.GA32507@elte.hu> <200611111620.24551.ak@suse.de> <20061112175050.A17720@unix-os.sc.intel.com> <200611130332.07569.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200611130332.07569.ak@suse.de> User-Agent: Mutt/1.4.2.2i X-ELTE-SpamScore: -2.8 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.8 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.5 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] -0.0 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Andi Kleen wrote: > Now if it causes device driver issues that's different of course. I > wasn't aware of this before. lets try my patch in -mm for a while. Had i ever noticed this hack in the first place i would have NAK-ed it. There is a fundamental design friction of a high-level feature like HOTPLUG_CPU /requiring/ a fundamental change to the lowlevel IRQ delivery mode! Such a requirement is broken and just serves to hide a flaw in the hotplug design - which flaw would trigger on i386 /anyway/, because i386 still uses logical delivery mode for APIC IPIs. Also, i'd like to have a description of how to reproduce those CPU hotplug problems, so that i can try to fix it. Ingo