Re: [PATCH v5 12/18] watchdog/hardlockup: Rename some "NMI watchdog" constants/function

Petr Mladek
2023-05-24T13:39:10Z

On Fri 2023-05-19 10:18:36, Douglas Anderson wrote:
> Do a search and replace of:
> - NMI_WATCHDOG_ENABLED => WATCHDOG_HARDLOCKUP_ENABLED
> - SOFT_WATCHDOG_ENABLED => WATCHDOG_SOFTOCKUP_ENABLED
> - watchdog_nmi_ => watchdog_hardlockup_
> - nmi_watchdog_available => watchdog_hardlockup_available
> - nmi_watchdog_user_enabled => watchdog_hardlockup_user_enabled
> - soft_watchdog_user_enabled => watchdog_softlockup_user_enabled
> - NMI_WATCHDOG_DEFAULT => WATCHDOG_HARDLOCKUP_DEFAULT
>
> Then update a few comments near where names were changed.
>
> This is specifically to make it less confusing when we want to
> introduce the buddy hardlockup detector, which isn't using NMIs. As
> part of this, we sanitized a few names for consistency.
>
> --- a/kernel/watchdog.c
> +++ b/kernel/watchdog.c
> @@ -30,17 +30,17 @@
> static DEFINE_MUTEX(watchdog_mutex);
>
> #if defined(CONFIG_HARDLOCKUP_DETECTOR) || defined(CONFIG_HAVE_NMI_WATCHDOG)
> -# define NMI_WATCHDOG_DEFAULT 1
> +# define WATCHDOG_HARDLOCKUP_DEFAULT 1
> #else
> -# define NMI_WATCHDOG_DEFAULT 0
> +# define WATCHDOG_HARDLOCKUP_DEFAULT 0
> #endif
>
> unsigned long __read_mostly watchdog_enabled;
> int __read_mostly watchdog_user_enabled = 1;
> -int __read_mostly nmi_watchdog_user_enabled = NMI_WATCHDOG_DEFAULT;
> -int __read_mostly soft_watchdog_user_enabled = 1;
> +int __read_mostly watchdog_hardlockup_user_enabled = WATCHDOG_HARDLOCKUP_DEFAULT;
> +int __read_mostly watchdog_softlockup_user_enabled = 1;

I still see nmi_watchdog_user_enabled and soft_watchdog_user_enabled
in include/linux/nmi.h. They are declared there and also mentioned
in a comment.

It seems that they do not actually need to be declared there.
I guess that it was need for the /proc stuff. But it was
moved into kernel/watchdog.c by the commit commit dd0693fdf054f2ed37
("watchdog: move watchdog sysctl interface to watchdog.c").

> int __read_mostly watchdog_thresh = 10;
> -static int __read_mostly nmi_watchdog_available;
> +static int __read_mostly watchdog_hardlockup_available;
>
> struct cpumask watchdog_cpumask __read_mostly;
> unsigned long *watchdog_cpumask_bits = cpumask_bits(&watchdog_cpumask);

Otherwise, I like the changes.

With the following:

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 83076bf70ce8..d14fe345eae9 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -17,8 +17,6 @@ void lockup_detector_soft_poweroff(void);
void lockup_detector_cleanup(void);

extern int watchdog_user_enabled;
-extern int nmi_watchdog_user_enabled;
-extern int soft_watchdog_user_enabled;
extern int watchdog_thresh;
extern unsigned long watchdog_enabled;

@@ -68,8 +66,8 @@ static inline void reset_hung_task_detector(void) { }
* 'watchdog_enabled' variable. Each lockup detector has its dedicated bit -
* bit 0 for the hard lockup detector and bit 1 for the soft lockup detector.
*
- * 'watchdog_user_enabled', 'nmi_watchdog_user_enabled' and
- * 'soft_watchdog_user_enabled' are variables that are only used as an
+ * 'watchdog_user_enabled', 'watchdog_hardlockup_user_enabled' and
+ * 'watchdog_softlockup_user_enabled' are variables that are only used as an
* 'interface' between the parameters in /proc/sys/kernel and the internal
* state bits in 'watchdog_enabled'. The 'watchdog_thresh' variable is
* handled differently because its value is not boolean, and the lockup

Reviewed-by: Petr Mladek <pmladek@suse.com>

Even better might be to remove the unused declaration in a separate
patch. I think that more declarations are not needed after moving
the /proc stuff into kernel/watchdog.c.

But it might also be fixed later.

Best Regards,
Petr