Messages in this thread Patch in this message | | | From | Ricardo Neri <> | Subject | [PATCH v6 28/29] x86/tsc: Restart NMI watchdog after refining tsc_khz | Date | Thu, 5 May 2022 17:00:07 -0700 |
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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 <ak@linux.intel.com> Cc: Stephane Eranian <eranian@google.com> Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com> Cc: iommu@lists.linux-foundation.org Cc: linuxppc-dev@lists.ozlabs.org Cc: x86@kernel.org Signed-off-by: Ricardo Neri <ricardo.neri-calderon@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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