From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750875AbZHJSwT (ORCPT ); Mon, 10 Aug 2009 14:52:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750715AbZHJSwS (ORCPT ); Mon, 10 Aug 2009 14:52:18 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:39440 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750711AbZHJSwR (ORCPT ); Mon, 10 Aug 2009 14:52:17 -0400 Date: Mon, 10 Aug 2009 20:51:56 +0200 From: Ingo Molnar To: Suresh Siddha Cc: "tglx@linutronix.de" , "hpa@zytor.com" , "linux-kernel@vger.kernel.org" , "Pallipadi, Venkatesh" , David Woodhouse , Jesse Barnes , Jay Fenlason Subject: Re: [patch 2/2] x86: arch specific support for remapping HPET MSIs Message-ID: <20090810185156.GC9601@elte.hu> References: <20090804190729.477649000@intel.com> <20090804190729.630510000@intel.com> <20090808151254.GC28892@elte.hu> <1249923516.27006.10839.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1249923516.27006.10839.camel@localhost.localdomain> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Suresh Siddha wrote: > On Sat, 2009-08-08 at 08:12 -0700, Ingo Molnar wrote: > > * Suresh Siddha wrote: > > > > > x86 arch support for remapping HPET MSI's by associating the HPET > > > timer block with the interrupt-remapping HW unit and setting up > > > appropriate irq_chip > > > > interesting. This means we'd materially utilize the irq-remapper > > not just on relatively obscure, virtualization related setups, > > but also in the native x86 bootup mode, on all (hpet+remap > > capable) Linux systems? > > Ingo, For native linux kernel, interrupt-remapping allows simple > and reliable irq migration from the process context (in addition > to its need for supporting cpu's capable of x2apic). And as such > solves the issues we had in the past with cpu hotplug and irq > migration. It's something much more directly useful than a fix for race conditions, and it would be used in a broader range of hardware than x2apic. (Not to denounce its other uses - i was just upbeat about it getting even more mainstream use.) Ingo