From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753701AbZFEBUp (ORCPT ); Thu, 4 Jun 2009 21:20:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752204AbZFEBUi (ORCPT ); Thu, 4 Jun 2009 21:20:38 -0400 Received: from mga02.intel.com ([134.134.136.20]:55933 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752138AbZFEBUh (ORCPT ); Thu, 4 Jun 2009 21:20:37 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.41,307,1241420400"; d="scan'208";a="521924071" Subject: Re: [patch] x64: Avoid irq_chip mask/unmask in fixup_irqs for interrupt-remapping From: Suresh Siddha Reply-To: suresh.b.siddha@intel.com To: "Eric W. Biederman" Cc: "mingo@elte.hu" , "hpa@zytor.com" , "tglx@linutronix.de" , "linux-kernel@vger.kernel.org" , "ak@linux.intel.com" , "travis@sgi.com" , "steiner@sgi.com" , Gary Hade In-Reply-To: References: <1244141989.27006.10369.camel@localhost.localdomain> Content-Type: text/plain Organization: Intel Corp Date: Thu, 04 Jun 2009 18:18:14 -0700 Message-Id: <1244164694.27006.10374.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.24.1 (2.24.1-2.fc10) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 2009-06-04 at 16:13 -0700, Eric W. Biederman wrote: > Suresh Siddha writes: > > > From: Suresh Siddha > > Subject: x64: Avoid irq_chip mask/unmask in fixup_irqs for interrupt-remapping > > > > In the presence of interrupt-remapping, irqs will be migrated in the > > process context and we don't do (and there is no need to) irq_chip mask/unmask > > while migrating the interrupt. > > > > Similarly fix the fixup_irqs() that get called during cpu offline and avoid > > calling irq_chip mask/unmask for irqs that are ok to be migrated in the > > process context. > > > > While we didn't observe any race condition with the existing code, > > this change takes complete advantage of interrupt-remapping in > > the newer generation platforms and avoids any potential HW lockup's > > (that often worry Eric :) > > You now apparently fail to migrate the irq threads in tandem with > the rest of the irqs. Eric, Are you referring to Gary's issues? As far as I understand, they don't happen in the presence of interrupt-remapping. Can you ack this patch, as this avoid touching IO-APIC and MSI entries and does fixup_irqs() in a much more reliable fashion. I haven't followed Gary's couple of patches related to non interrupt-remapping case. I will go through them and see how I can help there. thanks, suresh