linux-kernel - Re: [PATCH] V3 init/main.c Enable watchdog

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Date:   Wed, 24 Oct 2018 10:43:22 -0700
From:   Randy Dunlap <rdunlap@...radead.org>
To:     Laurence Oberman <loberman@...hat.com>,
        linux-kernel@...r.kernel.org
Cc:     tglx@...utronix.de
Subject: Re: [PATCH] V3 init/main.c Enable watchdog_thresh control from kernel
 line

On 10/24/18 9:53 AM, Laurence Oberman wrote:
> Both graphics and serial consoles are exposed to hard lockups
> when handling a large amount of messaging. The kernel watchdog_thresh
> parameter up to now has not been available to be set on the kernel line for
> early boot.
> This patch allows the setting of watchdog_thresh to be increased
> when needed to avoid the hard lockups in the console code.
> 
> Signed-off-by: Laurence Oberman <loberman@...hat.com>
> ---
>  Documentation/admin-guide/kernel-parameters.txt | 8 ++++++++
>  init/main.c                                     | 9 +++++++++
>  2 files changed, 17 insertions(+)
> 
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 4cdcd1a..cd8d588 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4932,6 +4932,14 @@
>  			or other driver-specific files in the
>  			Documentation/watchdog/ directory.
>  
> +	watchdog_thresh=
> +			This parameter is now available as a kernel line
> +			parameter. Use watchdog_thresh=30 as example
> +			This will allow early boot changes of the current
> +			default of 10s to be increased when needed to
> +			avoid hard lockups.
> +			Default: 10
> +

The first sentence isn't needed.  and s/10s/10 seconds/
How about this?

			This parameter allows early boot to change the default
			value of the watchdog timeout threshold from the default
			of 10 seconds to avoid hard lockups.  Example:
			watchdog_thresh=30

			

>  	workqueue.watchdog_thresh=
>  			If CONFIG_WQ_WATCHDOG is configured, workqueue can
>  			warn stall conditions and dump internal state to
> diff --git a/init/main.c b/init/main.c
> index 1c3f902..88cbed9 100644
> --- a/init/main.c
> +++ b/init/main.c
> @@ -1038,6 +1038,15 @@ static int __init set_debug_rodata(char *str)
>  __setup("rodata=", set_debug_rodata);
>  #endif
>  
> +static int __init
> +is_watchdog_thresh_setup(char *str)

No need to split that into 2 lines; just join them, please.

> +{
> +	get_option(&str, &watchdog_thresh);
> +	return 1;
> +}
> +__setup("watchdog_thresh=", is_watchdog_thresh_setup);
> +
> +
>  #ifdef CONFIG_STRICT_KERNEL_RWX
>  static void mark_readonly(void)
>  {
> 


-- 
~Randy