Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756778Ab0G2KRB (ORCPT ); Thu, 29 Jul 2010 06:17:01 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:28824 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756648Ab0G2KQt (ORCPT ); Thu, 29 Jul 2010 06:16:49 -0400 X-IronPort-AV: E=Sophos;i="4.55,279,1278302400"; d="scan'208";a="107549401" From: Ian Campbell To: linux-kernel@vger.kernel.org Cc: Ian Campbell , Thomas Gleixner , Jeremy Fitzhardinge , xen-devel@lists.xensource.com Subject: [PATCH 4/4] xen: do not suspend IPI IRQs. Date: Thu, 29 Jul 2010 11:16:35 +0100 Message-Id: <1280398595-29708-4-git-send-email-ian.campbell@citrix.com> X-Mailer: git-send-email 1.5.6.5 In-Reply-To: <1280398573.24292.1684.camel@zakaz.uk.xensource.com> References: <1280398573.24292.1684.camel@zakaz.uk.xensource.com> X-OriginalArrivalTime: 29 Jul 2010 10:16:48.0913 (UTC) FILETIME=[27CBB810:01CB2F07] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1588 Lines: 42 In general the semantics of IPIs are that they are are expected to continue functioning after dpm_suspend_noirq(). Specifically I have seen a deadlock between the callfunc IPI and the stop machine used by xen's do_suspend() routine. If one CPU has already called dpm_suspend_noirq() then there is a window where it can be sent a callfunc IPI before all the other CPUs have entered stop_cpu(). If this happens then the first CPU ends up spinning in stop_cpu() waiting for the other to rendezvous in state STOPMACHINE_PREPARE while the other is spinning in csd_lock_wait(). Signed-off-by: Ian Campbell Cc: Thomas Gleixner Cc: Jeremy Fitzhardinge Cc: xen-devel@lists.xensource.com Cc: # .32.x+: ab68ca3d: irq: Add new IRQ flag IRQF_NO_SUSPEND Cc: # .32.x+ --- drivers/xen/events.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index db8f506..28f133a 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -536,6 +536,7 @@ int bind_ipi_to_irqhandler(enum ipi_vector ipi, if (irq < 0) return irq; + irqflags |= IRQF_NO_SUSPEND; retval = request_irq(irq, handler, irqflags, devname, dev_id); if (retval != 0) { unbind_from_irq(irq); -- 1.5.6.5 -- 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/