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Date: Thu, 19 May 2011 09:26:31 -0700
From: Mandeep Singh Baines <msb@chromium.org>
To: Don Zickus <dzickus@redhat.com>
Cc: Mandeep Singh Baines <msb@chromium.org>, linux-kernel@vger.kernel.org,
        Marcin Slusarz <marcin.slusarz@gmail.com>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Frederic Weisbecker <fweisbec@gmail.com>, Ingo Molnar <mingo@elte.hu>
Subject: Re: [PATCH 1/4] watchdog: fix rounding issues in
 get_sample_period()
Message-ID: <20110519162631.GJ11023@google.com>
References: <1305588901-8141-1-git-send-email-msb@chromium.org>
 <20110518135302.GM29881@redhat.com>
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Don Zickus (dzickus@redhat.com) wrote:
> 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.
> 

No problem. Enjoy your time off:)

Ingo, since Don is out, would you mind acking the patches (assuming you're
happy). It simplifies pushing these patches into our local ChromiumOS tree
if I have an upstream ack.

> Cheers,
> Don
> 
> > 
> > Signed-off-by: Mandeep Singh Baines <msb@chromium.org>
> > Cc: Marcin Slusarz <marcin.slusarz@gmail.com>
> > Cc: Don Zickus <dzickus@redhat.com>
> > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
> > Cc: Frederic Weisbecker <fweisbec@gmail.com>
> > Cc: Ingo Molnar <mingo@elte.hu>
> > ---
> >  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
> >