From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760922AbYHAWmk (ORCPT ); Fri, 1 Aug 2008 18:42:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756649AbYHAWlq (ORCPT ); Fri, 1 Aug 2008 18:41:46 -0400 Received: from saraswathi.solana.com ([198.99.130.12]:52108 "EHLO saraswathi.solana.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754428AbYHAWlp (ORCPT ); Fri, 1 Aug 2008 18:41:45 -0400 Date: Fri, 1 Aug 2008 18:41:25 -0400 From: Jeff Dike To: stable@kernel.org Cc: LKML , uml-devel , WANG Cong Subject: [PATCH 2/14] uml: fix bad NTP interaction with clock Message-ID: <20080801224125.GA13729@c2.user-mode-linux.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From 2b95eda726d565d4abe3cac045022d3141a11b23 Mon Sep 17 00:00:00 2001 UML's supposed nanosecond clock interacts badly with NTP when NTP decides that the clock has drifted ahead and needs to be slowed down. Slowing down the clock is done by decrementing the cycle-to-nanosecond multiplier, which is 1. Decrementing that gives you 0 and time is stopped. This is fixed by switching to a microsecond clock, with a multiplier of 1000. Signed-off-by: Jeff Dike Cc: WANG Cong Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/um/kernel/time.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/um/kernel/time.c b/arch/um/kernel/time.c index e066e84..5036c81 100644 --- a/arch/um/kernel/time.c +++ b/arch/um/kernel/time.c @@ -74,7 +74,7 @@ static irqreturn_t um_timer(int irq, void *dev) static cycle_t itimer_read(void) { - return os_nsecs(); + return os_nsecs() / 1000; } static struct clocksource itimer_clocksource = { @@ -82,7 +82,7 @@ static struct clocksource itimer_clocksource = { .rating = 300, .read = itimer_read, .mask = CLOCKSOURCE_MASK(64), - .mult = 1, + .mult = 1000, .shift = 0, .flags = CLOCK_SOURCE_IS_CONTINUOUS, }; -- 1.5.5.1