From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1424013AbWKKP3K (ORCPT ); Sat, 11 Nov 2006 10:29:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1424014AbWKKP3K (ORCPT ); Sat, 11 Nov 2006 10:29:10 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:62416 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S1424013AbWKKP3H (ORCPT ); Sat, 11 Nov 2006 10:29:07 -0500 Date: Sat, 11 Nov 2006 16:27:57 +0100 From: Ingo Molnar To: Andi Kleen Cc: Andrew Morton , linux-kernel@vger.kernel.org, ashok.raj@intel.com Subject: Re: [patch] genapic: optimize & fix APIC mode setup Message-ID: <20061111152757.GA2407@elte.hu> References: <20061111151414.GA32507@elte.hu> <200611111620.24551.ak@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200611111620.24551.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: > On Saturday 11 November 2006 16:14, Ingo Molnar wrote: > > From: Ingo Molnar > > > > this patch fixes a couple of inconsistencies/problems i found while > > reviewing the x86_64 genapic code (when i was chasing mysterious eth0 > > timeouts that would only trigger if CPU_HOTPLUG is enabled): > > > > - AMD systems defaulted to the slower flat-physical mode instead > > of the flat-logical mode. The only restriction on AMD systems > > is that they should not use clustered APIC mode. > > This will open a race on CPU hotunplug unfortunately (common for multi > core suspend) Note that i386 still defaults to logical flat mode, so whatever hotplug CPU races there are, they need to be fixed! Given how rare CPU hotplug systems are i have no problem with having these races in the kernel for a while until it's fixed. Also, distro kernels enable CPU_HOTPLUG frequently. It is just ugly beyond recognition to switch the programming of the IRQ hardware on non-hotplug hardware just because a mostly-software feature (hotplug) is enabled ... if hotplug breaks suspend then fix it, dont hack it around (on one platform) by slowing down the system [and causing other problems] ... Ingo