Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752646Ab1EFO1R (ORCPT ); Fri, 6 May 2011 10:27:17 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:33057 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751205Ab1EFO1Q (ORCPT ); Fri, 6 May 2011 10:27:16 -0400 X-IronPort-AV: E=Sophos;i="4.64,326,1301875200"; d="scan'208";a="5639306" Date: Fri, 6 May 2011 15:28:38 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball-desktop To: "Tian, Kevin" CC: Thomas Gleixner , "linux-kernel@vger.kernel.org" , "mingo@redhat.com" , "hpa@zytor.com" , Ian Campbell , "JBeulich@novell.com" , "xen-devel@lists.xensource.com" Subject: RE: [PATCH v2 2/2] x86: don't unmask disabled irqs when migrating them In-Reply-To: <625BA99ED14B2D499DC4E29D8138F1505C8ED7F962@shsmsx502.ccr.corp.intel.com> Message-ID: References: <625BA99ED14B2D499DC4E29D8138F1505C8ED7F7E3@shsmsx502.ccr.corp.intel.com> <625BA99ED14B2D499DC4E29D8138F1505C8ED7F962@shsmsx502.ccr.corp.intel.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1702 Lines: 39 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? -- 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/