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 <[email protected]> Cc: Stephane Eranian <[email protected]> Cc: "Ravi V. Shankar" <[email protected]> Cc: [email protected] Cc: [email protected] Cc: [email protected] Signed-off-by: Ricardo Neri <[email protected]> --- 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 _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
