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

Doug Anderson
2023-05-25T23:33:50Z

Hi,

On Wed, May 24, 2023 at 6:38 AM Petr Mladek <pmladek@suse.com> wrote:
>
> 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.

Breadcrumbs: I squashed your suggestion together with Tom's patch and
posted the result:

https://lore.kernel.org/r/20230525162822.1.I0fb41d138d158c9230573eaa37dc56afa2fb14ee@changeid

-Doug