[External] Re: [PATCH 1/2] watchdog: refactor watchdog_hld functionality

[yunhui cui]

Hi Doug,

On Sat, Aug 30, 2025 at 5:34 AM Doug Anderson <dianders at chromium.org> wrote:
>
> Hi,
>
> On Wed, Aug 27, 2025 at 3:10 AM Yunhui Cui <cuiyunhui at bytedance.com> wrote:
> >
> > Move watchdog_hld.c to kernel/, and rename arm_pmu_irq_is_nmi()
> > to arch_pmu_irq_is_nmi() for cross-arch reusability.
> >
> > Signed-off-by: Yunhui Cui <cuiyunhui at bytedance.com>
> > ---
> >  arch/arm64/kernel/Makefile                   | 1 -
> >  drivers/perf/arm_pmu.c                       | 2 +-
> >  include/linux/nmi.h                          | 1 +
> >  include/linux/perf/arm_pmu.h                 | 2 --
> >  kernel/Makefile                              | 2 +-
> >  {arch/arm64/kernel => kernel}/watchdog_hld.c | 8 ++++++--
> >  6 files changed, 9 insertions(+), 7 deletions(-)
> >  rename {arch/arm64/kernel => kernel}/watchdog_hld.c (97%)
>
> I'm not a huge fan of the perf hardlockup detector and IMO we should
> maybe just delete it. Thus spreading it to support a new architecture
> isn't my favorite thing to do. Can't you use the buddy hardlockup
> detector?
>
> That being said, I did a quick look at your patch. I'm pretty sure you
> can't just move the arm64 "watchdog_hld.c" to be generic. Won't
> hw_nmi_get_sample_period() conflict with everyone else's (x86 and
> powerpc)?

After discussing whether to remove watchdog perf, it still seems
necessary to keep advancing with it. For the code, we just need to
decorate hw_nmi_get_sample_period() with __weak, right?


>
> -Doug
>

Thanks,
Yunhui