[RFC PATCH 22/23] watchdog/hardlockup/hpet: Only enable the HPET watchdog via a boot parameter

[Randy Dunlap]

On 06/13/2018 05:58 PM, Ricardo Neri wrote:
> On Tue, Jun 12, 2018 at 10:26:57PM -0700, Randy Dunlap wrote:
>> On 06/12/2018 05:57 PM, Ricardo Neri wrote:
>>> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
>>> index f2040d4..a8833c7 100644
>>> --- a/Documentation/admin-guide/kernel-parameters.txt
>>> +++ b/Documentation/admin-guide/kernel-parameters.txt
>>> @@ -2577,7 +2577,7 @@
>>>  			Format: [state][,regs][,debounce][,die]
>>>  
>>>  	nmi_watchdog=	[KNL,BUGS=X86] Debugging features for SMP kernels
>>> -			Format: [panic,][nopanic,][num]
>>> +			Format: [panic,][nopanic,][num,][hpet]
>>>  			Valid num: 0 or 1
>>>  			0 - turn hardlockup detector in nmi_watchdog off
>>>  			1 - turn hardlockup detector in nmi_watchdog on
>>
>> This says that I can use "nmi_watchdog=hpet" without using 0 or 1.
>> Is that correct?
> 
> Yes, this what I meant. In my view, if you set nmi_watchdog=hpet it
> implies that you want to activate the NMI watchdog. In this case, perf.
> 
> I can see how this will be ambiguous for the case of perf and arch NMI
> watchdogs.
> 
> Alternative, a new parameter could be added; such as nmi_watchdog_type. I
> didn't want to add it in this patchset as I think that a single parameter
> can handle the enablement and type of the NMI watchdog.
> 
> What do you think?

I think it's OK like it is.

thanks,
-- 
~Randy