linux-kernel - Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running perfctrs

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Date:	Fri, 27 Aug 2010 09:57:37 +0200
From:	Robert Richter <robert.richter@....com>
To:	Cyrill Gorcunov <gorcunov@...il.com>
CC:	Don Zickus <dzickus@...hat.com>, Ingo Molnar <mingo@...e.hu>,
	Peter Zijlstra <peterz@...radead.org>,
	Lin Ming <ming.m.lin@...el.com>,
	"fweisbec@...il.com" <fweisbec@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"Huang, Ying" <ying.huang@...el.com>,
	Yinghai Lu <yinghai@...nel.org>,
	Andi Kleen <andi@...stfloor.org>
Subject: Re: [PATCH -v3] perf, x86: try to handle unknown nmis with running
 perfctrs

On 26.08.10 14:02:50, Cyrill Gorcunov wrote:
> > diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c
> > index 4539b4b..9e65a7b 100644
> > --- a/arch/x86/kernel/cpu/perf_event_intel.c
> > +++ b/arch/x86/kernel/cpu/perf_event_intel.c
> > @@ -777,7 +777,9 @@ again:
> >  
> >  done:
> >  	intel_pmu_enable_all(0);
> > -	return handled;
> > +	if (!handled)
> > +		return handled;
> > +	return ++handled;
> >  }
> >  
> >  static struct event_constraint *
> > 
> 
> ok, it seems it just treat any unknown nmi as being came from PMU, no?

Yes, this just throws away all unknown nmis after a perf nmi. It
disables unknown nmi detection on this cpu type.

-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center

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