From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932496Ab3DBOxS (ORCPT ); Tue, 2 Apr 2013 10:53:18 -0400 Received: from smtp02.citrix.com ([66.165.176.63]:61528 "EHLO SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932213Ab3DBOxR (ORCPT ); Tue, 2 Apr 2013 10:53:17 -0400 X-IronPort-AV: E=Sophos;i="4.87,394,1363132800"; d="scan'208";a="16127942" Message-ID: <515AF0D9.80805@citrix.com> Date: Tue, 2 Apr 2013 15:53:13 +0100 From: David Vrabel User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.16) Gecko/20120428 Iceowl/1.0b1 Icedove/3.0.11 MIME-Version: 1.0 To: Konrad Rzeszutek Wilk CC: , , Keir Fraser Subject: Re: [Xen-devel] [PATCH] xen/evtchn: Handle VIRQ_TIMER before any other hardirq in event loop. References: <1364825261-25324-1-git-send-email-konrad.wilk@oracle.com> In-Reply-To: <1364825261-25324-1-git-send-email-konrad.wilk@oracle.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.80.2.76] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 01/04/13 15:07, Konrad Rzeszutek Wilk wrote: > From: Keir Fraser > > This avoids any other hardirq handler seeing a very stale jiffies > value immediately after wakeup from a long idle period. The one > observable symptom of this was a USB keyboard, with software keyboard > repeat, which would always repeat a key immediately that it was > pressed. This is due to the key press waking the guest, the key > handler immediately runs, sees an old jiffies value, and then that > jiffies value significantly updated, before the key is unpressed. It's a bit of hack but what else can you do when there is no generic mechanism to have different event priorities. Reviewed-by: David Vrabel The subject should be prefixed with: "xen/events" as this isn't a patch to the evtchn driver. David