Subject: Re: [PATCH v2] powerpc/watchdog: Use hrtimers for per-CPU heartbeat

From: Gautham R Shenoy <[email-masked]>
Date: Fri, 12 Apr 2019 11:34:06 +0530

Hello Nicholas,

On Tue, Apr 09, 2019 at 02:40:05PM +1000, Nicholas Piggin wrote:
> Using a jiffies timer creates a dependency on the tick_do_timer_cpu
> incrementing jiffies. If that CPU has locked up and jiffies is not
> incrementing, the watchdog heartbeat timer for all CPUs stops and
> creates false positives and confusing warnings on local CPUs, and
> also causes the SMP detector to stop, so the root cause is never
> detected.
> 
> Fix this by using hrtimer based timers for the watchdog heartbeat,
> like the generic kernel hardlockup detector.
> 
> Cc: Gautham R. Shenoy <[email-masked]>
> Reported-by: Ravikumar Bangoria <[email-masked]>
> Signed-off-by: Nicholas Piggin <[email-masked]>

Looks good to me.

Reviewed-by: Gautham R. Shenoy <[email-masked]>

--
Thanks and Regards
gautham.