linux-kernel - Re: [PATCH 4/4] watchdog: use suspend/resume interface in fixup_ht

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Message-ID: <20150804142750.GR42530@redhat.com>
Date:	Tue, 4 Aug 2015 10:27:50 -0400
From:	Don Zickus <dzickus@...hat.com>
To:	Michal Hocko <mhocko@...nel.org>
Cc:	Ulrich Obergfell <uobergfe@...hat.com>,
	linux-kernel@...r.kernel.org, akpm@...ux-foundation.org,
	atomlin@...hat.com, jolsa@...nel.org, eranian@...gle.com,
	cmetcalf@...hip.com, fweisbec@...il.com
Subject: Re: [PATCH 4/4] watchdog: use suspend/resume interface in
 fixup_ht_bug()

On Tue, Aug 04, 2015 at 03:31:30PM +0200, Michal Hocko wrote:
> On Sat 01-08-15 14:49:25, Ulrich Obergfell wrote:
> [...]
> > @@ -3368,7 +3368,10 @@ static __init int fixup_ht_bug(void)
> >  		return 0;
> >  	}
> >  
> > -	watchdog_nmi_disable_all();
> > +	if (watchdog_suspend() != 0) {
> > +		pr_info("failed to disable PMU erratum BJ122, BV98, HSD29 workaround\n");
> > +		return 0;
> > +	}
> 
> Is this really worth reporting to the log? What is an admin supposed to
> do about it?

I think it was more for developers to aid in debugging a strange behaviour
of the performance counters.

> <looking into the code>
> Ok, so kthread_park fails only when the kernel thread has already
> exited. Can this ever happen during this call path?

It might be overkill, but it is just a harmless informational failure
message.

Cheers,
Don
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