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

From: Randy Dunlap
Date: Wed Jun 13 2018 - 01:27:24 EST


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?

> @@ -2587,6 +2587,9 @@
> please see 'nowatchdog'.
> This is useful when you use a panic=... timeout and
> need the box quickly up again.
> + When hpet is specified, the NMI watchdog will be driven
> + by an HPET timer, if available in the system. Otherwise,
> + the perf-based implementation will be used.
>
> These settings can be accessed at runtime via
> the nmi_watchdog and hardlockup_panic sysctls.


thanks,
--
~Randy