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

Gautham R Shenoy ego at linux.vnet.ibm.com
Fri Apr 12 16:04:06 AEST 2019


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 <ego at linux.vnet.ibm.com>
> Reported-by: Ravikumar Bangoria <ravi.bangoria at in.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>

Looks good to me.

Reviewed-by: Gautham R. Shenoy <ego at linux.vnet.ibm.com>


--
Thanks and Regards
gautham.



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