linux-kernel - Re: [PATCH] x86, UV: Fix NMI handler for UV platforms

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Date:	Mon, 21 Mar 2011 19:43:46 +0300
From:	Cyrill Gorcunov <gorcunov@...il.com>
To:	Ingo Molnar <mingo@...e.hu>, Don Zickus <dzickus@...hat.com>
CC:	Jack Steiner <steiner@....com>, tglx@...utronix.de, hpa@...or.com,
	x86@...nel.org, linux-kernel@...r.kernel.org,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>
Subject: Re: [PATCH] x86, UV: Fix NMI handler for UV platforms

On 03/21/2011 07:26 PM, Cyrill Gorcunov wrote:
...
>>
>> Such code is extremely ugly. Please *reduce* the number of is_uv_system() type 
>> of hacks in core x86 code, not increase it!
>>
>> Any reason why a higher priority for the UV NMI handler cannot solve the 'perf 
>> eats the NMI' problem?
>>
>> Thanks,
>>
>> 	Ingo
> 
> Yeah, Don has made priority system for NMI notifiers. Need to look in.
> 

I think Jack might need to setup priority for his notifier, like

static struct notifier_block uv_dump_stack_nmi_nb = {
	.notifier_call	= uv_handle_nmi,
	.priority	= NMI_LOCAL_HIGH_PRIOR+1,
};

so it would be called before perf nmi. Don, am I right?

Since for perf nmis we do have

static __read_mostly struct notifier_block perf_event_nmi_notifier = {
	.notifier_call		= perf_event_nmi_handler,
	.next			= NULL,
	.priority		= NMI_LOCAL_LOW_PRIOR,
};

-- 
    Cyrill
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