On Tue, Oct 20, 2020 at 01:57:04PM -0700, Xi Wang wrote: > The main purpose of kernel watchdog is to test whether scheduler can > still schedule tasks on a cpu. In order to reduce latency / jitter > from periodically invoking watchdog reset in thread context, we can > simply test if pick_next_task can run. This is done by forcing resched > and checking rq->sched_count.
Whitespace exists for a reason, use more of it. Also, the above isn't actually accurate anymore and carried over from the previous implementation. > Compared to actually resetting watchdog > from cpu stop / migration threads, we lose coverage on: a migration > thread actually get picked and we actually context switch to the > migration thread. These steps are unlikely to silently fail. The > change would provide nearly the same level of protection with less > overhead. > > With this patch we can still switch back to the old method with the > boot option watchdog_touch_with_thread. However code for the old > method can be completely removed in the future. I'd suggest removing all the #ifdef and config muck. Either its a good idea or it's not.
