Re: [PATCH 1/2] watchdog: Introduce update_arch_nmi_watchdog

[Babu Moger]

On 10/6/2016 11:34 PM, Sam Ravnborg wrote:
> On Thu, Oct 06, 2016 at 03:16:42PM -0700, Babu Moger wrote:
> > Currently we do not have a way to enable/disable arch specific
> > watchdog handlers if it was implemented by any of the architectures.
> >
> > This patch introduces new function update_arch_nmi_watchdog
> > which can be used to enable/disable architecture specific NMI
> > watchdog handlers. Also exposes watchdog_enabled variable outside
> > so that arch specific nmi watchdogs can use it to implement
> > enalbe/disable behavour.
> >
> > Signed-off-by: Babu Moger <babu.moger@xxxxxxxxxx>
> > ---
> >   include/linux/nmi.h |    1 +
> >   kernel/watchdog.c   |   16 +++++++++++++---
> >   2 files changed, 14 insertions(+), 3 deletions(-)
> >
> > diff --git a/include/linux/nmi.h b/include/linux/nmi.h
> > index 4630eea..01b4830 100644
> > --- a/include/linux/nmi.h
> > +++ b/include/linux/nmi.h
> > @@ -66,6 +66,7 @@ static inline bool trigger_allbutself_cpu_backtrace(void)
> >   
> >   #ifdef CONFIG_LOCKUP_DETECTOR
> >   u64 hw_nmi_get_sample_period(int watchdog_thresh);
> > +extern unsigned long watchdog_enabled;
> The extern is within an #ifdef, but the definition later is
> valid alway.
> So extern definition should be outside the #ifdef to match the
> actual implementation.

     Ok. Sure.

> To manipulate / read watchdog_enabled two constants are used:
> NMI_WATCHDOG_ENABLED, SOFT_WATCHDOG_ENABLED

    Sure. I will bring these definitions to nmi.h from watchdog.c

> They should be visible too, so uses do not fall into the trap
> and uses constants (like in patch 2).

    Will re-post v2 version with these changes. Thanks for the comments.

> 	Sam