linux-kernel - Re: [PATCH] watchdog: Reduce message verbosity

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Date:   Wed, 1 Aug 2018 11:59:37 -0400
From:   Don Zickus <dzickus@...hat.com>
To:     Sinan Kaya <okaya@...nel.org>
Cc:     linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...nel.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Colin Ian King <colin.king@...onical.com>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [PATCH] watchdog: Reduce message verbosity

On Mon, Jul 30, 2018 at 12:43:34PM -0700, Sinan Kaya wrote:
> Hi Don,
> 
> On 7/30/2018 12:28 PM, Don Zickus wrote:
> > > [    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
> > > [    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
> > Hi Sinan,
> > 
> > Any reason why?  Usually when the 'perf event' fails, that indicates a
> > system problem.  And most folks don't boot with the 'debug' option.  This
> > means these unusual failures are hidden and become difficult to debug later
> > when it propagates.
> 
> Sorry, I should have been more clear. I'm only suppressing the first
> error message.
> 
> [    0.152492] NMI watchdog: Perf event create on CPU 0 failed with -2
> 
> Second message is still visible during boot. User knows that NMI watchdog is
> disabled.
> 
> [    0.156002] NMI watchdog: Perf NMI watchdog permanently disabled
> 
> Code is trying to probe the platform capabilities and is failing
> because of missing PMU in the system. If someone is interested in
> finding out why watchdog was disabled, they can turn on the debug
> message level.
> 
> > 
> > Or are you running the watchdog in a different configuration such that this
> > is a common nuisance that you are trying to suppress?
> 
> Yup, system doesn't support PMU.

Hi Sinan,

Oh, I see.  You are just trying to hide the always failing probe.  It seems
to make sense.

Acked-by: Don Zickus <dzickus@...hat.com>