From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933163Ab1ERNxP (ORCPT ); Wed, 18 May 2011 09:53:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:22481 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932856Ab1ERNxN (ORCPT ); Wed, 18 May 2011 09:53:13 -0400 Date: Wed, 18 May 2011 09:53:02 -0400 From: Don Zickus To: Mandeep Singh Baines Cc: linux-kernel@vger.kernel.org, Marcin Slusarz , Peter Zijlstra , Frederic Weisbecker , Ingo Molnar Subject: Re: [PATCH 1/4] watchdog: fix rounding issues in get_sample_period() Message-ID: <20110518135302.GM29881@redhat.com> References: <1305588901-8141-1-git-send-email-msb@chromium.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1305588901-8141-1-git-send-email-msb@chromium.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 16, 2011 at 04:34:58PM -0700, Mandeep Singh Baines wrote: > In get_sample_period(), softlockup_thresh is integer divided by 5 before > the multiplication by NSEC_PER_SEC. This results in softlockup_thresh > being rounded down to the nearest integer multiple of 5. > > For example, a softlockup_thresh of 4 rounds down to 0. Mandeep, Thanks for the patches. Unfortunately, I am taking some time off so I'll shephard these patches when I get back. For the most part they look fine, aside from Ingo's comments. Cheers, Don > > Signed-off-by: Mandeep Singh Baines > Cc: Marcin Slusarz > Cc: Don Zickus > Cc: Peter Zijlstra > Cc: Frederic Weisbecker > Cc: Ingo Molnar > --- > kernel/watchdog.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/kernel/watchdog.c b/kernel/watchdog.c > index 14733d4..a06972d 100644 > --- a/kernel/watchdog.c > +++ b/kernel/watchdog.c > @@ -110,7 +110,7 @@ static unsigned long get_sample_period(void) > * increment before the hardlockup detector generates > * a warning > */ > - return softlockup_thresh / 5 * NSEC_PER_SEC; > + return softlockup_thresh * (NSEC_PER_SEC / 5); > } > > /* Commands for resetting the watchdog */ > -- > 1.7.3.1 >