Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752417Ab1EFVnS (ORCPT ); Fri, 6 May 2011 17:43:18 -0400 Received: from mga01.intel.com ([192.55.52.88]:10376 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751212Ab1EFVnR convert rfc822-to-8bit (ORCPT ); Fri, 6 May 2011 17:43:17 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.64,328,1301900400"; d="scan'208";a="689287428" From: "Tian, Kevin" To: Stefano Stabellini CC: Thomas Gleixner , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "hpa@zytor.com" , Ian Campbell , "JBeulich@novell.com" , "xen-devel@lists.xensource.com" Date: Sat, 7 May 2011 05:43:12 +0800 Subject: RE: [PATCH v2 2/2] x86: don't unmask disabled irqs when migrating them Thread-Topic: [PATCH v2 2/2] x86: don't unmask disabled irqs when migrating them Thread-Index: AcwL+bTQLIdKuFPJQSKYXmpwNiVr0QAPNbiw Message-ID: <625BA99ED14B2D499DC4E29D8138F1505C8ED7F99D@shsmsx502.ccr.corp.intel.com> References: <625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E3@shsmsx502.ccr.corp.intel.com> <625BA99ED14B2D499DC4E29D8138F1505C8ED7F962@shsmsx502.ccr.corp.intel.com> In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1935 Lines: 50 > From: Stefano Stabellini [mailto:stefano.stabellini@eu.citrix.com] > Sent: Friday, May 06, 2011 10:29 PM > > On Fri, 6 May 2011, Tian, Kevin wrote: > > > From: Thomas Gleixner > > > Sent: Friday, May 06, 2011 6:00 PM > > > > > > On Fri, 6 May 2011, Tian, Kevin wrote: > > > > x86: don't unmask disabled irqs when migrating them > > > > > > > > it doesn't make sense to mask/unmask a disabled irq when migrating > > > > it from offlined cpu to another, because it's not expected to > > > > handle any instance of it. Current mask/set_affinity/unmask steps > > > > may trigger unexpected instance on disabled irq which then simply > > > > bug on when there is no handler for it. One failing example is observed in > Xen. > > > > Xen pvops > > > > > > So there is no handler, why the heck is there an irq action? > > > > > > if (!irq_has_action(irq) .... > > > continue; > > > > > > Should have caught an uninitialized interrupt. If Xen abuses > > > interrupts that way, then it rightfully explodes. And we do not fix it by magic > somewhere else. > > > > sorry that my bad description here. there does be a dummy handler > > registered on such irqs which simply throws out a BUG_ON when hit. I > > should just say such injection is not expected instead of no handler. > > :-) > > I don't think this patch is necessary anymore after the event channel handling > cleanup patches I have just sent to the list. > Could you please try the following two patches: > > http://marc.info/?l=linux-kernel&m=130468120032172&w=2 > http://marc.info/?l=linux-kernel&m=130468178200468&w=2 > > and let me know if you still need this patch? thanks, and I'll take a look at them. Thanks Kevin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/