Re: [PATCH v4 13/17] watchdog/hardlockup: detect hard lockups using secondary (buddy) CPUs

Nicholas Piggin
2023-05-05T02:36:48Z

On Fri May 5, 2023 at 8:13 AM AEST, Douglas Anderson wrote:
> From: Colin Cross <ccross@android.com>
>
> Implement a hardlockup detector that doesn't doesn't need any extra
> arch-specific support code to detect lockups. Instead of using
> something arch-specific we will use the buddy system, where each CPU
> watches out for another one. Specifically, each CPU will use its
> softlockup hrtimer to check that the next CPU is processing hrtimer
> interrupts by verifying that a counter is increasing.

Powerpc's watchdog has an SMP checker, did you see it? It's all to
all rather than buddy which makes it more complicated but arguably
bit better functionality.

Thanks,
Nick