From: Gautham R Shenoy <ego@linux.vnet.ibm.com>
To: Nicholas Piggin <npiggin@gmail.com>
Cc: "Gautham R . Shenoy" <ego@linux.vnet.ibm.com>,
Ravikumar Bangoria <ravi.bangoria@in.ibm.com>,
linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH v2] powerpc/watchdog: Use hrtimers for per-CPU heartbeat
Date: Fri, 12 Apr 2019 11:34:06 +0530 [thread overview]
Message-ID: <20190412060406.GA26155@in.ibm.com> (raw)
In-Reply-To: <20190409044005.26446-1-npiggin@gmail.com>
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@linux.vnet.ibm.com>
> Reported-by: Ravikumar Bangoria <ravi.bangoria@in.ibm.com>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Looks good to me.
Reviewed-by: Gautham R. Shenoy <ego@linux.vnet.ibm.com>
--
Thanks and Regards
gautham.
next prev parent reply other threads:[~2019-04-12 6:06 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-09 4:40 [PATCH v2] powerpc/watchdog: Use hrtimers for per-CPU heartbeat Nicholas Piggin
2019-04-11 3:23 ` Ravi Bangoria
2019-04-12 6:04 ` Gautham R Shenoy [this message]
2019-05-03 6:59 ` Michael Ellerman
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