From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751648Ab1ABHVv (ORCPT ); Sun, 2 Jan 2011 02:21:51 -0500 Received: from mail.windriver.com ([147.11.1.11]:34202 "EHLO mail.windriver.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731Ab1ABHVq (ORCPT ); Sun, 2 Jan 2011 02:21:46 -0500 From: Paul Gortmaker To: stable@kernel.org, linux-kernel@vger.kernel.org Cc: stable-review@kernel.org, Jeremy Fitzhardinge , Tom Kopec , Daniel Stodden , Paul Gortmaker Subject: [34-longterm 030/260] xen: handle events as edge-triggered Date: Sun, 2 Jan 2011 02:15:26 -0500 Message-Id: <1293952756-15010-31-git-send-email-paul.gortmaker@windriver.com> X-Mailer: git-send-email 1.7.3.3 In-Reply-To: <1293952756-15010-1-git-send-email-paul.gortmaker@windriver.com> References: <1293952756-15010-1-git-send-email-paul.gortmaker@windriver.com> X-OriginalArrivalTime: 02 Jan 2011 07:20:39.0210 (UTC) FILETIME=[8E9DC8A0:01CBAA4D] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Jeremy Fitzhardinge commit dffe2e1e1a1ddb566a76266136c312801c66dcf7 upstream. Xen events are logically edge triggered, as Xen only calls the event upcall when an event is newly set, but not continuously as it remains set. As a result, use handle_edge_irq rather than handle_level_irq. This has the important side-effect of fixing a long-standing bug of events getting lost if: - an event's interrupt handler is running - the event is migrated to a different vcpu - the event is re-triggered The most noticable symptom of these lost events is occasional lockups of blkfront. Many thanks to Tom Kopec and Daniel Stodden in tracking this down. Signed-off-by: Jeremy Fitzhardinge Cc: Tom Kopec Cc: Daniel Stodden Signed-off-by: Paul Gortmaker --- drivers/xen/events.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 28f133a..cc72dad 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -363,7 +363,7 @@ int bind_evtchn_to_irq(unsigned int evtchn) irq = find_unbound_irq(); set_irq_chip_and_handler_name(irq, &xen_dynamic_chip, - handle_level_irq, "event"); + handle_edge_irq, "event"); evtchn_to_irq[evtchn] = irq; irq_info[irq] = mk_evtchn_info(evtchn); -- 1.7.3.3