The HPET hardlockup detector relies on tsc_khz to estimate the value of
that the TSC will have when its HPET channel fires. A refined tsc_khz
helps to estimate better the expected TSC value.
Using the early value of tsc_khz may lead to a large error in the expected
TSC value. Restarting the NMI watchdog detector has the effect of kicking
its HPET channel and make use of the refined tsc_khz.
When the HPET hardlockup is not in use, restarting the NMI watchdog is
a noop.
Cc: Andi Kleen <a...@linux.intel.com>
Cc: Stephane Eranian <eran...@google.com>
Cc: "Ravi V. Shankar" <ravi.v.shan...@intel.com>
Cc: iommu@lists.linux-foundation.org
Cc: linuxppc-...@lists.ozlabs.org
Cc: x...@kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calde...@linux.intel.com>
---
Changes since v5:
* Introduced this patch
Changes since v4
* N/A
Changes since v3
* N/A
Changes since v2:
* N/A
Changes since v1:
* N/A
---
arch/x86/kernel/tsc.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index cafacb2e58cc..cc1843044d88 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -1386,6 +1386,12 @@ static void tsc_refine_calibration_work(struct
work_struct *work)
/* Inform the TSC deadline clockevent devices about the recalibration */
lapic_update_tsc_freq();
+ /*
+ * If in use, the HPET hardlockup detector relies on tsc_khz.
+ * Reconfigure it to make use of the refined tsc_khz.
+ */
+ lockup_detector_reconfigure();
+
/* Update the sched_clock() rate to match the clocksource one */
for_each_possible_cpu(cpu)
set_cyc2ns_scale(tsc_khz, cpu, tsc_stop);
--
2.17.1
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