2 files changed, 37 insertions, 30 deletions

diff --git a/arch/x86/kernel/cpu/aperfmperf.c b/arch/x86/kernel/cpu/aperfmperf.c
index d869c8671e36..7cf7c70b6ef2 100644
--- a/arch/x86/kernel/cpu/aperfmperf.c
+++ b/arch/x86/kernel/cpu/aperfmperf.c
@@ -8,20 +8,25 @@
  * This file is licensed under GPLv2.
  */
 
-#include <linux/jiffies.h>
+#include <linux/delay.h>
+#include <linux/ktime.h>
 #include <linux/math64.h>
 #include <linux/percpu.h>
 #include <linux/smp.h>
 
 struct aperfmperf_sample {
 	unsigned int	khz;
-	unsigned long	jiffies;
+	ktime_t	time;
 	u64	aperf;
 	u64	mperf;
 };
 
 static DEFINE_PER_CPU(struct aperfmperf_sample, samples);
 
+#define APERFMPERF_CACHE_THRESHOLD_MS	10
+#define APERFMPERF_REFRESH_DELAY_MS	20
+#define APERFMPERF_STALE_THRESHOLD_MS	1000
+
 /*
  * aperfmperf_snapshot_khz()
  * On the current CPU, snapshot APERF, MPERF, and jiffies
@@ -33,9 +38,11 @@ static void aperfmperf_snapshot_khz(void *dummy)
 	u64 aperf, aperf_delta;
 	u64 mperf, mperf_delta;
 	struct aperfmperf_sample *s = this_cpu_ptr(&samples);
+	ktime_t now = ktime_get();
+	s64 time_delta = ktime_ms_delta(now, s->time);
 
-	/* Don't bother re-computing within 10 ms */
-	if (time_before(jiffies, s->jiffies + HZ/100))
+	/* Don't bother re-computing within the cache threshold time. */
+	if (time_delta < APERFMPERF_CACHE_THRESHOLD_MS)
 		return;
 
 	rdmsrl(MSR_IA32_APERF, aperf);
@@ -51,22 +58,21 @@ static void aperfmperf_snapshot_khz(void *dummy)
 	if (mperf_delta == 0)
 		return;
 
-	/*
-	 * if (cpu_khz * aperf_delta) fits into ULLONG_MAX, then
-	 *	khz = (cpu_khz * aperf_delta) / mperf_delta
-	 */
-	if (div64_u64(ULLONG_MAX, cpu_khz) > aperf_delta)
-		s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta);
-	else	/* khz = aperf_delta / (mperf_delta / cpu_khz) */
-		s->khz = div64_u64(aperf_delta,
-			div64_u64(mperf_delta, cpu_khz));
-	s->jiffies = jiffies;
+	s->time = now;
 	s->aperf = aperf;
 	s->mperf = mperf;
+
+	/* If the previous iteration was too long ago, discard it. */
+	if (time_delta > APERFMPERF_STALE_THRESHOLD_MS)
+		s->khz = 0;
+	else
+		s->khz = div64_u64((cpu_khz * aperf_delta), mperf_delta);
 }
 
 unsigned int arch_freq_get_on_cpu(int cpu)
 {
+	unsigned int khz;
+
 	if (!cpu_khz)
 		return 0;
 
@@ -74,6 +80,12 @@ unsigned int arch_freq_get_on_cpu(int cpu)
 		return 0;
 
 	smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);
+	khz = per_cpu(samples.khz, cpu);
+	if (khz)
+		return khz;
+
+	msleep(APERFMPERF_REFRESH_DELAY_MS);
+	smp_call_function_single(cpu, aperfmperf_snapshot_khz, NULL, 1);
 
 	return per_cpu(samples.khz, cpu);
 }
diff --git a/arch/x86/kernel/hpet.c b/arch/x86/kernel/hpet.c
index 16f82a3aaec7..8ce4212e2b8d 100644
--- a/arch/x86/kernel/hpet.c
+++ b/arch/x86/kernel/hpet.c
@@ -345,21 +345,10 @@ static int hpet_shutdown(struct clock_event_device *evt, int timer)
 	return 0;
 }
 
-static int hpet_resume(struct clock_event_device *evt, int timer)
-{
-	if (!timer) {
-		hpet_enable_legacy_int();
-	} else {
-		struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
-
-		irq_domain_deactivate_irq(irq_get_irq_data(hdev->irq));
-		irq_domain_activate_irq(irq_get_irq_data(hdev->irq));
-		disable_hardirq(hdev->irq);
-		irq_set_affinity(hdev->irq, cpumask_of(hdev->cpu));
-		enable_irq(hdev->irq);
-	}
+static int hpet_resume(struct clock_event_device *evt)
+{
+	hpet_enable_legacy_int();
 	hpet_print_config();
-
 	return 0;
 }
 
@@ -417,7 +406,7 @@ static int hpet_legacy_set_periodic(struct clock_event_device *evt)
 
 static int hpet_legacy_resume(struct clock_event_device *evt)
 {
-	return hpet_resume(evt, 0);
+	return hpet_resume(evt);
 }
 
 static int hpet_legacy_next_event(unsigned long delta,
@@ -510,8 +499,14 @@ static int hpet_msi_set_periodic(struct clock_event_device *evt)
 static int hpet_msi_resume(struct clock_event_device *evt)
 {
 	struct hpet_dev *hdev = EVT_TO_HPET_DEV(evt);
+	struct irq_data *data = irq_get_irq_data(hdev->irq);
+	struct msi_msg msg;
 
-	return hpet_resume(evt, hdev->num);
+	/* Restore the MSI msg and unmask the interrupt */
+	irq_chip_compose_msi_msg(data, &msg);
+	hpet_msi_write(hdev, &msg);
+	hpet_msi_unmask(data);
+	return 0;
 }
 
 static int hpet_msi_next_event(unsigned long delta,