Merge tag 'pm-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management updates from Rafael Wysocki:
 "This time the majority of changes go to the cpufreq subsystem (and to
  the intel_pstate driver in particular) and there are some updates in
  the generic power domains framework, cpuidle, tools and a couple of
  other places.

  One thing worth mentioning is that the intel_pstate's sysfs interface
  has been reworked to be more consistent with the general expectations
  of the cpufreq core and less confusing, hopefully for the better.
  Also, we have a new cpufreq driver for Tegra186 and new hardware
  support in intel_pstata and the Mediatek cpufreq driver.

  Apart from that, the AnalyzeSuspend utility for system suspend
  profiling gets a companion called AnalyzeBoot for the analogous
  profiling of system boot and they both go into one place under
  tools/power/pm-graph/.

  The rest is mostly fixes, cleanups and code reorganization.

  Specifics:

   - Rework the intel_pstate driver's sysfs interface to make it more
     straightforward and more intuitive (Rafael Wysocki).

   - Make intel_pstate support all processors which advertise HWP
     (hardware-managed P-states) to the kernel in all operation modes
     and make it use the load-based P-state selection algorithm on a
     wider range of systems in the active mode (Rafael Wysocki).

   - Add cpufreq driver for Tegra186 (Mikko Perttunen).

   - Add support for Gemini Lake SoCs to intel_pstate (David Box).

   - Add support for MT8176 and MT817x to the Mediatek cpufreq driver
     and clean up that driver a bit (Daniel Kurtz).

   - Clean up intel_pstate and optimize it slightly (Rafael Wysocki).

   - Update the schedutil cpufreq governor, mostly to fix a couple of
     issues with it related to specific workloads, and rework its sysfs
     tunable and initialization a bit (Rafael Wysocki, Viresh Kumar).

   - Fix minor issues in the imx6q, dbx500 and qoriq cpufreq drivers
     (Christophe Jaillet, Irina Tirdea, Leonard Crestez, Viresh Kumar,
     YuanTian Tang).

   - Add file patterns for cpufreq DT bindings to MAINTAINERS (Geert
     Uytterhoeven).

   - Add support for "always on" power domains to the genpd (generic
     power domains) framework and clean up that code somewhat (Ulf
     Hansson, Lina Iyer, Viresh Kumar).

   - Fix minor issues in the powernv cpuidle driver and clean it up
     (Anton Blanchard, Gautham Shenoy).

   - Move the AnalyzeSuspend utility under tools/power/pm-graph/ and add
     an analogous boot-profiling utility called AnalyzeBoot to it (Todd
     Brandt).

   - Add rk3328 support to the rockchip-io AVS (Adaptive Voltage
     Scaling) driver (David Wu).

   - Fix minor issues in the cpuidle core, the intel_pstate_tracer
     utility, the devfreq framework and the PM core documentation
     (Chanwoo Choi, Doug Smythies, Johan Hovold, Marcin Nowakowski)"

* tag 'pm-4.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (56 commits)
  PM / runtime: Document autosuspend-helper side effects
  PM / runtime: Fix autosuspend documentation
  tools: power: pm-graph: Package makefile and man pages
  tools: power: pm-graph: AnalyzeBoot v2.0
  tools: power: pm-graph: AnalyzeSuspend v4.6
  cpufreq: Add Tegra186 cpufreq driver
  cpufreq: imx6q: Fix error handling code
  cpufreq: imx6q: Set max suspend_freq to avoid changes during suspend
  cpufreq: imx6q: Fix handling EPROBE_DEFER from regulator
  cpuidle: powernv: Avoid a branch in the core snooze_loop() loop
  cpuidle: powernv: Don't continually set thread priority in snooze_loop()
  cpuidle: powernv: Don't bounce between low and very low thread priority
  cpuidle: cpuidle-cps: remove unused variable
  tools/power/x86/intel_pstate_tracer: Adjust directory ownership
  cpufreq: schedutil: Use policy-dependent transition delays
  cpufreq: schedutil: Reduce frequencies slower
  PM / devfreq: Move struct devfreq_governor to devfreq directory
  PM / Domains: Ignore domain-idle-states that are not compatible
  cpufreq: intel_pstate: Add support for Gemini Lake
  powernv-cpuidle: Validate DT property array size
  ...

2 files changed, 66 insertions, 28 deletions

diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c
index 54c577578da6..76877a62b5fa 100644
--- a/kernel/sched/cpufreq_schedutil.c
+++ b/kernel/sched/cpufreq_schedutil.c
@@ -61,6 +61,11 @@ struct sugov_cpu {
 	unsigned long util;
 	unsigned long max;
 	unsigned int flags;
+
+	/* The field below is for single-CPU policies only. */
+#ifdef CONFIG_NO_HZ_COMMON
+	unsigned long saved_idle_calls;
+#endif
 };
 
 static DEFINE_PER_CPU(struct sugov_cpu, sugov_cpu);
@@ -93,22 +98,23 @@ static void sugov_update_commit(struct sugov_policy *sg_policy, u64 time,
 {
 	struct cpufreq_policy *policy = sg_policy->policy;
 
+	if (sg_policy->next_freq == next_freq)
+		return;
+
+	if (sg_policy->next_freq > next_freq)
+		next_freq = (sg_policy->next_freq + next_freq) >> 1;
+
+	sg_policy->next_freq = next_freq;
 	sg_policy->last_freq_update_time = time;
 
 	if (policy->fast_switch_enabled) {
-		if (sg_policy->next_freq == next_freq) {
-			trace_cpu_frequency(policy->cur, smp_processor_id());
-			return;
-		}
-		sg_policy->next_freq = next_freq;
 		next_freq = cpufreq_driver_fast_switch(policy, next_freq);
 		if (next_freq == CPUFREQ_ENTRY_INVALID)
 			return;
 
 		policy->cur = next_freq;
 		trace_cpu_frequency(next_freq, smp_processor_id());
-	} else if (sg_policy->next_freq != next_freq) {
-		sg_policy->next_freq = next_freq;
+	} else {
 		sg_policy->work_in_progress = true;
 		irq_work_queue(&sg_policy->irq_work);
 	}
@@ -192,6 +198,19 @@ static void sugov_iowait_boost(struct sugov_cpu *sg_cpu, unsigned long *util,
 	sg_cpu->iowait_boost >>= 1;
 }
 
+#ifdef CONFIG_NO_HZ_COMMON
+static bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu)
+{
+	unsigned long idle_calls = tick_nohz_get_idle_calls();
+	bool ret = idle_calls == sg_cpu->saved_idle_calls;
+
+	sg_cpu->saved_idle_calls = idle_calls;
+	return ret;
+}
+#else
+static inline bool sugov_cpu_is_busy(struct sugov_cpu *sg_cpu) { return false; }
+#endif /* CONFIG_NO_HZ_COMMON */
+
 static void sugov_update_single(struct update_util_data *hook, u64 time,
 				unsigned int flags)
 {
@@ -200,6 +219,7 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
 	struct cpufreq_policy *policy = sg_policy->policy;
 	unsigned long util, max;
 	unsigned int next_f;
+	bool busy;
 
 	sugov_set_iowait_boost(sg_cpu, time, flags);
 	sg_cpu->last_update = time;
@@ -207,40 +227,37 @@ static void sugov_update_single(struct update_util_data *hook, u64 time,
 	if (!sugov_should_update_freq(sg_policy, time))
 		return;
 
+	busy = sugov_cpu_is_busy(sg_cpu);
+
 	if (flags & SCHED_CPUFREQ_RT_DL) {
 		next_f = policy->cpuinfo.max_freq;
 	} else {
 		sugov_get_util(&util, &max);
 		sugov_iowait_boost(sg_cpu, &util, &max);
 		next_f = get_next_freq(sg_policy, util, max);
+		/*
+		 * Do not reduce the frequency if the CPU has not been idle
+		 * recently, as the reduction is likely to be premature then.
+		 */
+		if (busy && next_f < sg_policy->next_freq)
+			next_f = sg_policy->next_freq;
 	}
 	sugov_update_commit(sg_policy, time, next_f);
 }
 
-static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
-					   unsigned long util, unsigned long max,
-					   unsigned int flags)
+static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu)
 {
 	struct sugov_policy *sg_policy = sg_cpu->sg_policy;
 	struct cpufreq_policy *policy = sg_policy->policy;
-	unsigned int max_f = policy->cpuinfo.max_freq;
 	u64 last_freq_update_time = sg_policy->last_freq_update_time;
+	unsigned long util = 0, max = 1;
 	unsigned int j;
 
-	if (flags & SCHED_CPUFREQ_RT_DL)
-		return max_f;
-
-	sugov_iowait_boost(sg_cpu, &util, &max);
-
 	for_each_cpu(j, policy->cpus) {
-		struct sugov_cpu *j_sg_cpu;
+		struct sugov_cpu *j_sg_cpu = &per_cpu(sugov_cpu, j);
 		unsigned long j_util, j_max;
 		s64 delta_ns;
 
-		if (j == smp_processor_id())
-			continue;
-
-		j_sg_cpu = &per_cpu(sugov_cpu, j);
 		/*
 		 * If the CPU utilization was last updated before the previous
 		 * frequency update and the time elapsed between the last update
@@ -254,7 +271,7 @@ static unsigned int sugov_next_freq_shared(struct sugov_cpu *sg_cpu,
 			continue;
 		}
 		if (j_sg_cpu->flags & SCHED_CPUFREQ_RT_DL)
-			return max_f;
+			return policy->cpuinfo.max_freq;
 
 		j_util = j_sg_cpu->util;
 		j_max = j_sg_cpu->max;
@@ -289,7 +306,11 @@ static void sugov_update_shared(struct update_util_data *hook, u64 time,
 	sg_cpu->last_update = time;
 
 	if (sugov_should_update_freq(sg_policy, time)) {
-		next_f = sugov_next_freq_shared(sg_cpu, util, max, flags);
+		if (flags & SCHED_CPUFREQ_RT_DL)
+			next_f = sg_policy->policy->cpuinfo.max_freq;
+		else
+			next_f = sugov_next_freq_shared(sg_cpu);
+
 		sugov_update_commit(sg_policy, time, next_f);
 	}
 
@@ -473,7 +494,6 @@ static int sugov_init(struct cpufreq_policy *policy)
 {
 	struct sugov_policy *sg_policy;
 	struct sugov_tunables *tunables;
-	unsigned int lat;
 	int ret = 0;
 
 	/* State should be equivalent to EXIT */
@@ -512,10 +532,16 @@ static int sugov_init(struct cpufreq_policy *policy)
 		goto stop_kthread;
 	}
 
-	tunables->rate_limit_us = LATENCY_MULTIPLIER;
-	lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
-	if (lat)
-		tunables->rate_limit_us *= lat;
+	if (policy->transition_delay_us) {
+		tunables->rate_limit_us = policy->transition_delay_us;
+	} else {
+		unsigned int lat;
+
+		tunables->rate_limit_us = LATENCY_MULTIPLIER;
+		lat = policy->cpuinfo.transition_latency / NSEC_PER_USEC;
+		if (lat)
+			tunables->rate_limit_us *= lat;
+	}
 
 	policy->governor_data = sg_policy;
 	sg_policy->tunables = tunables;
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index 7fe53be86077..64c97fc130c4 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -993,6 +993,18 @@ ktime_t tick_nohz_get_sleep_length(void)
 	return ts->sleep_length;
 }
 
+/**
+ * tick_nohz_get_idle_calls - return the current idle calls counter value
+ *
+ * Called from the schedutil frequency scaling governor in scheduler context.
+ */
+unsigned long tick_nohz_get_idle_calls(void)
+{
+	struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched);
+
+	return ts->idle_calls;
+}
+
 static void tick_nohz_account_idle_ticks(struct tick_sched *ts)
 {
 #ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE