[PATCH 1/2] watchdog: refactor watchdog_hld functionality

[Doug Anderson]

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)?

-Doug