Merge tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull power management and ACPI updates from Rafael Wysocki:
 "This time the majority of changes go into cpufreq and they are
  significant.

  First off, the way CPU frequency updates are triggered is different
  now.  Instead of having to set up and manage a deferrable timer for
  each CPU in the system to evaluate and possibly change its frequency
  periodically, cpufreq governors set up callbacks to be invoked by the
  scheduler on a regular basis (basically on utilization updates).  The
  "old" governors, "ondemand" and "conservative", still do all of their
  work in process context (although that is triggered by the scheduler
  now), but intel_pstate does it all in the callback invoked by the
  scheduler with no need for any additional asynchronous processing.

  Of course, this eliminates the overhead related to the management of
  all those timers, but also it allows the cpufreq governor code to be
  simplified quite a bit.  On top of that, the common code and data
  structures used by the "ondemand" and "conservative" governors are
  cleaned up and made more straightforward and some long-standing and
  quite annoying problems are addressed.  In particular, the handling of
  governor sysfs attributes is modified and the related locking becomes
  more fine grained which allows some concurrency problems to be avoided
  (particularly deadlocks with the core cpufreq code).

  In principle, the new mechanism for triggering frequency updates
  allows utilization information to be passed from the scheduler to
  cpufreq.  Although the current code doesn't make use of it, in the
  works is a new cpufreq governor that will make decisions based on the
  scheduler's utilization data.  That should allow the scheduler and
  cpufreq to work more closely together in the long run.

  In addition to the core and governor changes, cpufreq drivers are
  updated too.  Fixes and optimizations go into intel_pstate, the
  cpufreq-dt driver is updated on top of some modification in the
  Operating Performance Points (OPP) framework and there are fixes and
  other updates in the powernv cpufreq driver.

  Apart from the cpufreq updates there is some new ACPICA material,
  including a fix for a problem introduced by previous ACPICA updates,
  and some less significant changes in the ACPI code, like CPPC code
  optimizations, ACPI processor driver cleanups and support for loading
  ACPI tables from initrd.

  Also updated are the generic power domains framework, the Intel RAPL
  power capping driver and the turbostat utility and we have a bunch of
  traditional assorted fixes and cleanups.

  Specifics:

   - Redesign of cpufreq governors and the intel_pstate driver to make
     them use callbacks invoked by the scheduler to trigger CPU
     frequency evaluation instead of using per-CPU deferrable timers for
     that purpose (Rafael Wysocki).

   - Reorganization and cleanup of cpufreq governor code to make it more
     straightforward and fix some concurrency problems in it (Rafael
     Wysocki, Viresh Kumar).

   - Cleanup and improvements of locking in the cpufreq core (Viresh
     Kumar).

   - Assorted cleanups in the cpufreq core (Rafael Wysocki, Viresh
     Kumar, Eric Biggers).

   - intel_pstate driver updates including fixes, optimizations and a
     modification to make it enable enable hardware-coordinated P-state
     selection (HWP) by default if supported by the processor (Philippe
     Longepe, Srinivas Pandruvada, Rafael Wysocki, Viresh Kumar, Felipe
     Franciosi).

   - Operating Performance Points (OPP) framework updates to improve its
     handling of voltage regulators and device clocks and updates of the
     cpufreq-dt driver on top of that (Viresh Kumar, Jon Hunter).

   - Updates of the powernv cpufreq driver to fix initialization and
     cleanup problems in it and correct its worker thread handling with
     respect to CPU offline, new powernv_throttle tracepoint (Shilpasri
     Bhat).

   - ACPI cpufreq driver optimization and cleanup (Rafael Wysocki).

   - ACPICA updates including one fix for a regression introduced by
     previos changes in the ACPICA code (Bob Moore, Lv Zheng, David Box,
     Colin Ian King).

   - Support for installing ACPI tables from initrd (Lv Zheng).

   - Optimizations of the ACPI CPPC code (Prashanth Prakash, Ashwin
     Chaugule).

   - Support for _HID(ACPI0010) devices (ACPI processor containers) and
     ACPI processor driver cleanups (Sudeep Holla).

   - Support for ACPI-based enumeration of the AMBA bus (Graeme Gregory,
     Aleksey Makarov).

   - Modification of the ACPI PCI IRQ management code to make it treat
     255 in the Interrupt Line register as "not connected" on x86 (as
     per the specification) and avoid attempts to use that value as a
     valid interrupt vector (Chen Fan).

   - ACPI APEI fixes related to resource leaks (Josh Hunt).

   - Removal of modularity from a few ACPI drivers (BGRT, GHES,
     intel_pmic_crc) that cannot be built as modules in practice (Paul
     Gortmaker).

   - PNP framework update to make it treat ACPI_RESOURCE_TYPE_SERIAL_BUS
     as a valid resource type (Harb Abdulhamid).

   - New device ID (future AMD I2C controller) in the ACPI driver for
     AMD SoCs (APD) and in the designware I2C driver (Xiangliang Yu).

   - Assorted ACPI cleanups (Colin Ian King, Kaiyen Chang, Oleg Drokin).

   - cpuidle menu governor optimization to avoid a square root
     computation in it (Rasmus Villemoes).

   - Fix for potential use-after-free in the generic device properties
     framework (Heikki Krogerus).

   - Updates of the generic power domains (genpd) framework including
     support for multiple power states of a domain, fixes and debugfs
     output improvements (Axel Haslam, Jon Hunter, Laurent Pinchart,
     Geert Uytterhoeven).

   - Intel RAPL power capping driver updates to reduce IPI overhead in
     it (Jacob Pan).

   - System suspend/hibernation code cleanups (Eric Biggers, Saurabh
     Sengar).

   - Year 2038 fix for the process freezer (Abhilash Jindal).

   - turbostat utility updates including new features (decoding of more
     registers and CPUID fields, sub-second intervals support, GFX MHz
     and RC6 printout, --out command line option), fixes (syscall jitter
     detection and workaround, reductioin of the number of syscalls
     made, fixes related to Xeon x200 processors, compiler warning
     fixes) and cleanups (Len Brown, Hubert Chrzaniuk, Chen Yu)"

* tag 'pm+acpi-4.6-rc1-1' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm: (182 commits)
  tools/power turbostat: bugfix: TDP MSRs print bits fixing
  tools/power turbostat: correct output for MSR_NHM_SNB_PKG_CST_CFG_CTL dump
  tools/power turbostat: call __cpuid() instead of __get_cpuid()
  tools/power turbostat: indicate SMX and SGX support
  tools/power turbostat: detect and work around syscall jitter
  tools/power turbostat: show GFX%rc6
  tools/power turbostat: show GFXMHz
  tools/power turbostat: show IRQs per CPU
  tools/power turbostat: make fewer systems calls
  tools/power turbostat: fix compiler warnings
  tools/power turbostat: add --out option for saving output in a file
  tools/power turbostat: re-name "%Busy" field to "Busy%"
  tools/power turbostat: Intel Xeon x200: fix turbo-ratio decoding
  tools/power turbostat: Intel Xeon x200: fix erroneous bclk value
  tools/power turbostat: allow sub-sec intervals
  ACPI / APEI: ERST: Fixed leaked resources in erst_init
  ACPI / APEI: Fix leaked resources
  intel_pstate: Do not skip samples partially
  intel_pstate: Remove freq calculation from intel_pstate_calc_busy()
  intel_pstate: Move intel_pstate_calc_busy() into get_target_pstate_use_performance()
  ...

1 files changed, 403 insertions, 363 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index e0d111024d48..1c25ef405616 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -18,95 +18,193 @@
 
 #include <linux/export.h>
 #include <linux/kernel_stat.h>
+#include <linux/sched.h>
 #include <linux/slab.h>
 
 #include "cpufreq_governor.h"
 
-static struct attribute_group *get_sysfs_attr(struct dbs_data *dbs_data)
-{
-	if (have_governor_per_policy())
-		return dbs_data->cdata->attr_group_gov_pol;
-	else
-		return dbs_data->cdata->attr_group_gov_sys;
-}
+static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs);
+
+static DEFINE_MUTEX(gov_dbs_data_mutex);
 
-void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
+/* Common sysfs tunables */
+/**
+ * store_sampling_rate - update sampling rate effective immediately if needed.
+ *
+ * If new rate is smaller than the old, simply updating
+ * dbs.sampling_rate might not be appropriate. For example, if the
+ * original sampling_rate was 1 second and the requested new sampling rate is 10
+ * ms because the user needs immediate reaction from ondemand governor, but not
+ * sure if higher frequency will be required or not, then, the governor may
+ * change the sampling rate too late; up to 1 second later. Thus, if we are
+ * reducing the sampling rate, we need to make the new value effective
+ * immediately.
+ *
+ * This must be called with dbs_data->mutex held, otherwise traversing
+ * policy_dbs_list isn't safe.
+ */
+ssize_t store_sampling_rate(struct dbs_data *dbs_data, const char *buf,
+			    size_t count)
 {
-	struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
-	struct od_dbs_tuners *od_tuners = dbs_data->tuners;
-	struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
-	struct cpufreq_policy *policy = cdbs->shared->policy;
-	unsigned int sampling_rate;
-	unsigned int max_load = 0;
-	unsigned int ignore_nice;
-	unsigned int j;
+	struct policy_dbs_info *policy_dbs;
+	unsigned int rate;
+	int ret;
+	ret = sscanf(buf, "%u", &rate);
+	if (ret != 1)
+		return -EINVAL;
 
-	if (dbs_data->cdata->governor == GOV_ONDEMAND) {
-		struct od_cpu_dbs_info_s *od_dbs_info =
-				dbs_data->cdata->get_cpu_dbs_info_s(cpu);
+	dbs_data->sampling_rate = max(rate, dbs_data->min_sampling_rate);
 
+	/*
+	 * We are operating under dbs_data->mutex and so the list and its
+	 * entries can't be freed concurrently.
+	 */
+	list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+		mutex_lock(&policy_dbs->timer_mutex);
 		/*
-		 * Sometimes, the ondemand governor uses an additional
-		 * multiplier to give long delays. So apply this multiplier to
-		 * the 'sampling_rate', so as to keep the wake-up-from-idle
-		 * detection logic a bit conservative.
+		 * On 32-bit architectures this may race with the
+		 * sample_delay_ns read in dbs_update_util_handler(), but that
+		 * really doesn't matter.  If the read returns a value that's
+		 * too big, the sample will be skipped, but the next invocation
+		 * of dbs_update_util_handler() (when the update has been
+		 * completed) will take a sample.
+		 *
+		 * If this runs in parallel with dbs_work_handler(), we may end
+		 * up overwriting the sample_delay_ns value that it has just
+		 * written, but it will be corrected next time a sample is
+		 * taken, so it shouldn't be significant.
 		 */
-		sampling_rate = od_tuners->sampling_rate;
-		sampling_rate *= od_dbs_info->rate_mult;
+		gov_update_sample_delay(policy_dbs, 0);
+		mutex_unlock(&policy_dbs->timer_mutex);
+	}
 
-		ignore_nice = od_tuners->ignore_nice_load;
-	} else {
-		sampling_rate = cs_tuners->sampling_rate;
-		ignore_nice = cs_tuners->ignore_nice_load;
+	return count;
+}
+EXPORT_SYMBOL_GPL(store_sampling_rate);
+
+/**
+ * gov_update_cpu_data - Update CPU load data.
+ * @dbs_data: Top-level governor data pointer.
+ *
+ * Update CPU load data for all CPUs in the domain governed by @dbs_data
+ * (that may be a single policy or a bunch of them if governor tunables are
+ * system-wide).
+ *
+ * Call under the @dbs_data mutex.
+ */
+void gov_update_cpu_data(struct dbs_data *dbs_data)
+{
+	struct policy_dbs_info *policy_dbs;
+
+	list_for_each_entry(policy_dbs, &dbs_data->policy_dbs_list, list) {
+		unsigned int j;
+
+		for_each_cpu(j, policy_dbs->policy->cpus) {
+			struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+			j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall,
+								  dbs_data->io_is_busy);
+			if (dbs_data->ignore_nice_load)
+				j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
+		}
 	}
+}
+EXPORT_SYMBOL_GPL(gov_update_cpu_data);
+
+static inline struct dbs_data *to_dbs_data(struct kobject *kobj)
+{
+	return container_of(kobj, struct dbs_data, kobj);
+}
+
+static inline struct governor_attr *to_gov_attr(struct attribute *attr)
+{
+	return container_of(attr, struct governor_attr, attr);
+}
+
+static ssize_t governor_show(struct kobject *kobj, struct attribute *attr,
+			     char *buf)
+{
+	struct dbs_data *dbs_data = to_dbs_data(kobj);
+	struct governor_attr *gattr = to_gov_attr(attr);
+
+	return gattr->show(dbs_data, buf);
+}
+
+static ssize_t governor_store(struct kobject *kobj, struct attribute *attr,
+			      const char *buf, size_t count)
+{
+	struct dbs_data *dbs_data = to_dbs_data(kobj);
+	struct governor_attr *gattr = to_gov_attr(attr);
+	int ret = -EBUSY;
+
+	mutex_lock(&dbs_data->mutex);
+
+	if (dbs_data->usage_count)
+		ret = gattr->store(dbs_data, buf, count);
+
+	mutex_unlock(&dbs_data->mutex);
+
+	return ret;
+}
+
+/*
+ * Sysfs Ops for accessing governor attributes.
+ *
+ * All show/store invocations for governor specific sysfs attributes, will first
+ * call the below show/store callbacks and the attribute specific callback will
+ * be called from within it.
+ */
+static const struct sysfs_ops governor_sysfs_ops = {
+	.show	= governor_show,
+	.store	= governor_store,
+};
+
+unsigned int dbs_update(struct cpufreq_policy *policy)
+{
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	unsigned int ignore_nice = dbs_data->ignore_nice_load;
+	unsigned int max_load = 0;
+	unsigned int sampling_rate, io_busy, j;
+
+	/*
+	 * Sometimes governors may use an additional multiplier to increase
+	 * sample delays temporarily.  Apply that multiplier to sampling_rate
+	 * so as to keep the wake-up-from-idle detection logic a bit
+	 * conservative.
+	 */
+	sampling_rate = dbs_data->sampling_rate * policy_dbs->rate_mult;
+	/*
+	 * For the purpose of ondemand, waiting for disk IO is an indication
+	 * that you're performance critical, and not that the system is actually
+	 * idle, so do not add the iowait time to the CPU idle time then.
+	 */
+	io_busy = dbs_data->io_is_busy;
 
 	/* Get Absolute Load */
 	for_each_cpu(j, policy->cpus) {
-		struct cpu_dbs_info *j_cdbs;
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
 		u64 cur_wall_time, cur_idle_time;
 		unsigned int idle_time, wall_time;
 		unsigned int load;
-		int io_busy = 0;
-
-		j_cdbs = dbs_data->cdata->get_cpu_cdbs(j);
 
-		/*
-		 * For the purpose of ondemand, waiting for disk IO is
-		 * an indication that you're performance critical, and
-		 * not that the system is actually idle. So do not add
-		 * the iowait time to the cpu idle time.
-		 */
-		if (dbs_data->cdata->governor == GOV_ONDEMAND)
-			io_busy = od_tuners->io_is_busy;
 		cur_idle_time = get_cpu_idle_time(j, &cur_wall_time, io_busy);
 
-		wall_time = (unsigned int)
-			(cur_wall_time - j_cdbs->prev_cpu_wall);
+		wall_time = cur_wall_time - j_cdbs->prev_cpu_wall;
 		j_cdbs->prev_cpu_wall = cur_wall_time;
 
-		if (cur_idle_time < j_cdbs->prev_cpu_idle)
-			cur_idle_time = j_cdbs->prev_cpu_idle;
-
-		idle_time = (unsigned int)
-			(cur_idle_time - j_cdbs->prev_cpu_idle);
-		j_cdbs->prev_cpu_idle = cur_idle_time;
+		if (cur_idle_time <= j_cdbs->prev_cpu_idle) {
+			idle_time = 0;
+		} else {
+			idle_time = cur_idle_time - j_cdbs->prev_cpu_idle;
+			j_cdbs->prev_cpu_idle = cur_idle_time;
+		}
 
 		if (ignore_nice) {
-			u64 cur_nice;
-			unsigned long cur_nice_jiffies;
-
-			cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE] -
-					 cdbs->prev_cpu_nice;
-			/*
-			 * Assumption: nice time between sampling periods will
-			 * be less than 2^32 jiffies for 32 bit sys
-			 */
-			cur_nice_jiffies = (unsigned long)
-					cputime64_to_jiffies64(cur_nice);
+			u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 
-			cdbs->prev_cpu_nice =
-				kcpustat_cpu(j).cpustat[CPUTIME_NICE];
-			idle_time += jiffies_to_usecs(cur_nice_jiffies);
+			idle_time += cputime_to_usecs(cur_nice - j_cdbs->prev_cpu_nice);
+			j_cdbs->prev_cpu_nice = cur_nice;
 		}
 
 		if (unlikely(!wall_time || wall_time < idle_time))
@@ -128,10 +226,10 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 		 * dropped down. So we perform the copy only once, upon the
 		 * first wake-up from idle.)
 		 *
-		 * Detecting this situation is easy: the governor's deferrable
-		 * timer would not have fired during CPU-idle periods. Hence
-		 * an unusually large 'wall_time' (as compared to the sampling
-		 * rate) indicates this scenario.
+		 * Detecting this situation is easy: the governor's utilization
+		 * update handler would not have run during CPU-idle periods.
+		 * Hence, an unusually large 'wall_time' (as compared to the
+		 * sampling rate) indicates this scenario.
 		 *
 		 * prev_load can be zero in two cases and we must recalculate it
 		 * for both cases:
@@ -156,222 +254,224 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 		if (load > max_load)
 			max_load = load;
 	}
-
-	dbs_data->cdata->gov_check_cpu(cpu, max_load);
+	return max_load;
 }
-EXPORT_SYMBOL_GPL(dbs_check_cpu);
+EXPORT_SYMBOL_GPL(dbs_update);
 
-void gov_add_timers(struct cpufreq_policy *policy, unsigned int delay)
+static void gov_set_update_util(struct policy_dbs_info *policy_dbs,
+				unsigned int delay_us)
 {
-	struct dbs_data *dbs_data = policy->governor_data;
-	struct cpu_dbs_info *cdbs;
+	struct cpufreq_policy *policy = policy_dbs->policy;
 	int cpu;
 
+	gov_update_sample_delay(policy_dbs, delay_us);
+	policy_dbs->last_sample_time = 0;
+
 	for_each_cpu(cpu, policy->cpus) {
-		cdbs = dbs_data->cdata->get_cpu_cdbs(cpu);
-		cdbs->timer.expires = jiffies + delay;
-		add_timer_on(&cdbs->timer, cpu);
+		struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu);
+
+		cpufreq_set_update_util_data(cpu, &cdbs->update_util);
 	}
 }
-EXPORT_SYMBOL_GPL(gov_add_timers);
 
-static inline void gov_cancel_timers(struct cpufreq_policy *policy)
+static inline void gov_clear_update_util(struct cpufreq_policy *policy)
 {
-	struct dbs_data *dbs_data = policy->governor_data;
-	struct cpu_dbs_info *cdbs;
 	int i;
 
-	for_each_cpu(i, policy->cpus) {
-		cdbs = dbs_data->cdata->get_cpu_cdbs(i);
-		del_timer_sync(&cdbs->timer);
-	}
-}
+	for_each_cpu(i, policy->cpus)
+		cpufreq_set_update_util_data(i, NULL);
 
-void gov_cancel_work(struct cpu_common_dbs_info *shared)
-{
-	/* Tell dbs_timer_handler() to skip queuing up work items. */
-	atomic_inc(&shared->skip_work);
-	/*
-	 * If dbs_timer_handler() is already running, it may not notice the
-	 * incremented skip_work, so wait for it to complete to prevent its work
-	 * item from being queued up after the cancel_work_sync() below.
-	 */
-	gov_cancel_timers(shared->policy);
-	/*
-	 * In case dbs_timer_handler() managed to run and spawn a work item
-	 * before the timers have been canceled, wait for that work item to
-	 * complete and then cancel all of the timers set up by it.  If
-	 * dbs_timer_handler() runs again at that point, it will see the
-	 * positive value of skip_work and won't spawn any more work items.
-	 */
-	cancel_work_sync(&shared->work);
-	gov_cancel_timers(shared->policy);
-	atomic_set(&shared->skip_work, 0);
+	synchronize_sched();
 }
-EXPORT_SYMBOL_GPL(gov_cancel_work);
 
-/* Will return if we need to evaluate cpu load again or not */
-static bool need_load_eval(struct cpu_common_dbs_info *shared,
-			   unsigned int sampling_rate)
+static void gov_cancel_work(struct cpufreq_policy *policy)
 {
-	if (policy_is_shared(shared->policy)) {
-		ktime_t time_now = ktime_get();
-		s64 delta_us = ktime_us_delta(time_now, shared->time_stamp);
-
-		/* Do nothing if we recently have sampled */
-		if (delta_us < (s64)(sampling_rate / 2))
-			return false;
-		else
-			shared->time_stamp = time_now;
-	}
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
 
-	return true;
+	gov_clear_update_util(policy_dbs->policy);
+	irq_work_sync(&policy_dbs->irq_work);
+	cancel_work_sync(&policy_dbs->work);
+	atomic_set(&policy_dbs->work_count, 0);
+	policy_dbs->work_in_progress = false;
 }
 
 static void dbs_work_handler(struct work_struct *work)
 {
-	struct cpu_common_dbs_info *shared = container_of(work, struct
-					cpu_common_dbs_info, work);
+	struct policy_dbs_info *policy_dbs;
 	struct cpufreq_policy *policy;
-	struct dbs_data *dbs_data;
-	unsigned int sampling_rate, delay;
-	bool eval_load;
-
-	policy = shared->policy;
-	dbs_data = policy->governor_data;
+	struct dbs_governor *gov;
 
-	/* Kill all timers */
-	gov_cancel_timers(policy);
+	policy_dbs = container_of(work, struct policy_dbs_info, work);
+	policy = policy_dbs->policy;
+	gov = dbs_governor_of(policy);
 
-	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
-
-		sampling_rate = cs_tuners->sampling_rate;
-	} else {
-		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
-
-		sampling_rate = od_tuners->sampling_rate;
-	}
-
-	eval_load = need_load_eval(shared, sampling_rate);
+	/*
+	 * Make sure cpufreq_governor_limits() isn't evaluating load or the
+	 * ondemand governor isn't updating the sampling rate in parallel.
+	 */
+	mutex_lock(&policy_dbs->timer_mutex);
+	gov_update_sample_delay(policy_dbs, gov->gov_dbs_timer(policy));
+	mutex_unlock(&policy_dbs->timer_mutex);
 
+	/* Allow the utilization update handler to queue up more work. */
+	atomic_set(&policy_dbs->work_count, 0);
 	/*
-	 * Make sure cpufreq_governor_limits() isn't evaluating load in
-	 * parallel.
+	 * If the update below is reordered with respect to the sample delay
+	 * modification, the utilization update handler may end up using a stale
+	 * sample delay value.
 	 */
-	mutex_lock(&shared->timer_mutex);
-	delay = dbs_data->cdata->gov_dbs_timer(policy, eval_load);
-	mutex_unlock(&shared->timer_mutex);
+	smp_wmb();
+	policy_dbs->work_in_progress = false;
+}
 
-	atomic_dec(&shared->skip_work);
+static void dbs_irq_work(struct irq_work *irq_work)
+{
+	struct policy_dbs_info *policy_dbs;
 
-	gov_add_timers(policy, delay);
+	policy_dbs = container_of(irq_work, struct policy_dbs_info, irq_work);
+	schedule_work(&policy_dbs->work);
 }
 
-static void dbs_timer_handler(unsigned long data)
+static void dbs_update_util_handler(struct update_util_data *data, u64 time,
+				    unsigned long util, unsigned long max)
 {
-	struct cpu_dbs_info *cdbs = (struct cpu_dbs_info *)data;
-	struct cpu_common_dbs_info *shared = cdbs->shared;
+	struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util);
+	struct policy_dbs_info *policy_dbs = cdbs->policy_dbs;
+	u64 delta_ns, lst;
 
 	/*
-	 * Timer handler may not be allowed to queue the work at the moment,
-	 * because:
-	 * - Another timer handler has done that
-	 * - We are stopping the governor
-	 * - Or we are updating the sampling rate of the ondemand governor
+	 * The work may not be allowed to be queued up right now.
+	 * Possible reasons:
+	 * - Work has already been queued up or is in progress.
+	 * - It is too early (too little time from the previous sample).
 	 */
-	if (atomic_inc_return(&shared->skip_work) > 1)
-		atomic_dec(&shared->skip_work);
-	else
-		queue_work(system_wq, &shared->work);
-}
+	if (policy_dbs->work_in_progress)
+		return;
 
-static void set_sampling_rate(struct dbs_data *dbs_data,
-		unsigned int sampling_rate)
-{
-	if (dbs_data->cdata->governor == GOV_CONSERVATIVE) {
-		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
-		cs_tuners->sampling_rate = sampling_rate;
-	} else {
-		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
-		od_tuners->sampling_rate = sampling_rate;
+	/*
+	 * If the reads below are reordered before the check above, the value
+	 * of sample_delay_ns used in the computation may be stale.
+	 */
+	smp_rmb();
+	lst = READ_ONCE(policy_dbs->last_sample_time);
+	delta_ns = time - lst;
+	if ((s64)delta_ns < policy_dbs->sample_delay_ns)
+		return;
+
+	/*
+	 * If the policy is not shared, the irq_work may be queued up right away
+	 * at this point.  Otherwise, we need to ensure that only one of the
+	 * CPUs sharing the policy will do that.
+	 */
+	if (policy_dbs->is_shared) {
+		if (!atomic_add_unless(&policy_dbs->work_count, 1, 1))
+			return;
+
+		/*
+		 * If another CPU updated last_sample_time in the meantime, we
+		 * shouldn't be here, so clear the work counter and bail out.
+		 */
+		if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) {
+			atomic_set(&policy_dbs->work_count, 0);
+			return;
+		}
 	}
+
+	policy_dbs->last_sample_time = time;
+	policy_dbs->work_in_progress = true;
+	irq_work_queue(&policy_dbs->irq_work);
 }
 
-static int alloc_common_dbs_info(struct cpufreq_policy *policy,
-				 struct common_dbs_data *cdata)
+static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy,
+						     struct dbs_governor *gov)
 {
-	struct cpu_common_dbs_info *shared;
+	struct policy_dbs_info *policy_dbs;
 	int j;
 
-	/* Allocate memory for the common information for policy->cpus */
-	shared = kzalloc(sizeof(*shared), GFP_KERNEL);
-	if (!shared)
-		return -ENOMEM;
+	/* Allocate memory for per-policy governor data. */
+	policy_dbs = gov->alloc();
+	if (!policy_dbs)
+		return NULL;
 
-	/* Set shared for all CPUs, online+offline */
-	for_each_cpu(j, policy->related_cpus)
-		cdata->get_cpu_cdbs(j)->shared = shared;
+	policy_dbs->policy = policy;
+	mutex_init(&policy_dbs->timer_mutex);
+	atomic_set(&policy_dbs->work_count, 0);
+	init_irq_work(&policy_dbs->irq_work, dbs_irq_work);
+	INIT_WORK(&policy_dbs->work, dbs_work_handler);
 
-	mutex_init(&shared->timer_mutex);
-	atomic_set(&shared->skip_work, 0);
-	INIT_WORK(&shared->work, dbs_work_handler);
-	return 0;
+	/* Set policy_dbs for all CPUs, online+offline */
+	for_each_cpu(j, policy->related_cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
+
+		j_cdbs->policy_dbs = policy_dbs;
+		j_cdbs->update_util.func = dbs_update_util_handler;
+	}
+	return policy_dbs;
 }
 
-static void free_common_dbs_info(struct cpufreq_policy *policy,
-				 struct common_dbs_data *cdata)
+static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs,
+				 struct dbs_governor *gov)
 {
-	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(policy->cpu);
-	struct cpu_common_dbs_info *shared = cdbs->shared;
 	int j;
 
-	mutex_destroy(&shared->timer_mutex);
+	mutex_destroy(&policy_dbs->timer_mutex);
 
-	for_each_cpu(j, policy->cpus)
-		cdata->get_cpu_cdbs(j)->shared = NULL;
+	for_each_cpu(j, policy_dbs->policy->related_cpus) {
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
 
-	kfree(shared);
+		j_cdbs->policy_dbs = NULL;
+		j_cdbs->update_util.func = NULL;
+	}
+	gov->free(policy_dbs);
 }
 
-static int cpufreq_governor_init(struct cpufreq_policy *policy,
-				 struct dbs_data *dbs_data,
-				 struct common_dbs_data *cdata)
+static int cpufreq_governor_init(struct cpufreq_policy *policy)
 {
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct dbs_data *dbs_data;
+	struct policy_dbs_info *policy_dbs;
 	unsigned int latency;
-	int ret;
+	int ret = 0;
 
 	/* State should be equivalent to EXIT */
 	if (policy->governor_data)
 		return -EBUSY;
 
-	if (dbs_data) {
-		if (WARN_ON(have_governor_per_policy()))
-			return -EINVAL;
+	policy_dbs = alloc_policy_dbs_info(policy, gov);
+	if (!policy_dbs)
+		return -ENOMEM;
 
-		ret = alloc_common_dbs_info(policy, cdata);
-		if (ret)
-			return ret;
+	/* Protect gov->gdbs_data against concurrent updates. */
+	mutex_lock(&gov_dbs_data_mutex);
 
+	dbs_data = gov->gdbs_data;
+	if (dbs_data) {
+		if (WARN_ON(have_governor_per_policy())) {
+			ret = -EINVAL;
+			goto free_policy_dbs_info;
+		}
+		policy_dbs->dbs_data = dbs_data;
+		policy->governor_data = policy_dbs;
+
+		mutex_lock(&dbs_data->mutex);
 		dbs_data->usage_count++;
-		policy->governor_data = dbs_data;
-		return 0;
+		list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
+		mutex_unlock(&dbs_data->mutex);
+		goto out;
 	}
 
 	dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL);
-	if (!dbs_data)
-		return -ENOMEM;
-
-	ret = alloc_common_dbs_info(policy, cdata);
-	if (ret)
-		goto free_dbs_data;
+	if (!dbs_data) {
+		ret = -ENOMEM;
+		goto free_policy_dbs_info;
+	}
 
-	dbs_data->cdata = cdata;
-	dbs_data->usage_count = 1;
+	INIT_LIST_HEAD(&dbs_data->policy_dbs_list);
+	mutex_init(&dbs_data->mutex);
 
-	ret = cdata->init(dbs_data, !policy->governor->initialized);
+	ret = gov->init(dbs_data, !policy->governor->initialized);
 	if (ret)
-		goto free_common_dbs_info;
+		goto free_policy_dbs_info;
 
 	/* policy latency is in ns. Convert it to us first */
 	latency = policy->cpuinfo.transition_latency / 1000;
@@ -381,216 +481,156 @@ static int cpufreq_governor_init(struct cpufreq_policy *policy,
 	/* Bring kernel and HW constraints together */
 	dbs_data->min_sampling_rate = max(dbs_data->min_sampling_rate,
 					  MIN_LATENCY_MULTIPLIER * latency);
-	set_sampling_rate(dbs_data, max(dbs_data->min_sampling_rate,
-					latency * LATENCY_MULTIPLIER));
+	dbs_data->sampling_rate = max(dbs_data->min_sampling_rate,
+				      LATENCY_MULTIPLIER * latency);
 
 	if (!have_governor_per_policy())
-		cdata->gdbs_data = dbs_data;
+		gov->gdbs_data = dbs_data;
 
-	policy->governor_data = dbs_data;
+	policy->governor_data = policy_dbs;
 
-	ret = sysfs_create_group(get_governor_parent_kobj(policy),
-				 get_sysfs_attr(dbs_data));
-	if (ret)
-		goto reset_gdbs_data;
+	policy_dbs->dbs_data = dbs_data;
+	dbs_data->usage_count = 1;
+	list_add(&policy_dbs->list, &dbs_data->policy_dbs_list);
 
-	return 0;
+	gov->kobj_type.sysfs_ops = &governor_sysfs_ops;
+	ret = kobject_init_and_add(&dbs_data->kobj, &gov->kobj_type,
+				   get_governor_parent_kobj(policy),
+				   "%s", gov->gov.name);
+	if (!ret)
+		goto out;
+
+	/* Failure, so roll back. */
+	pr_err("cpufreq: Governor initialization failed (dbs_data kobject init error %d)\n", ret);
 
-reset_gdbs_data:
 	policy->governor_data = NULL;
 
 	if (!have_governor_per_policy())
-		cdata->gdbs_data = NULL;
-	cdata->exit(dbs_data, !policy->governor->initialized);
-free_common_dbs_info:
-	free_common_dbs_info(policy, cdata);
-free_dbs_data:
+		gov->gdbs_data = NULL;
+	gov->exit(dbs_data, !policy->governor->initialized);
 	kfree(dbs_data);
+
+free_policy_dbs_info:
+	free_policy_dbs_info(policy_dbs, gov);
+
+out:
+	mutex_unlock(&gov_dbs_data_mutex);
 	return ret;
 }
 
-static int cpufreq_governor_exit(struct cpufreq_policy *policy,
-				 struct dbs_data *dbs_data)
+static int cpufreq_governor_exit(struct cpufreq_policy *policy)
 {
-	struct common_dbs_data *cdata = dbs_data->cdata;
-	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(policy->cpu);
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	int count;
 
-	/* State should be equivalent to INIT */
-	if (!cdbs->shared || cdbs->shared->policy)
-		return -EBUSY;
+	/* Protect gov->gdbs_data against concurrent updates. */
+	mutex_lock(&gov_dbs_data_mutex);
+
+	mutex_lock(&dbs_data->mutex);
+	list_del(&policy_dbs->list);
+	count = --dbs_data->usage_count;
+	mutex_unlock(&dbs_data->mutex);
 
-	if (!--dbs_data->usage_count) {
-		sysfs_remove_group(get_governor_parent_kobj(policy),
-				   get_sysfs_attr(dbs_data));
+	if (!count) {
+		kobject_put(&dbs_data->kobj);
 
 		policy->governor_data = NULL;
 
 		if (!have_governor_per_policy())
-			cdata->gdbs_data = NULL;
+			gov->gdbs_data = NULL;
 
-		cdata->exit(dbs_data, policy->governor->initialized == 1);
+		gov->exit(dbs_data, policy->governor->initialized == 1);
+		mutex_destroy(&dbs_data->mutex);
 		kfree(dbs_data);
 	} else {
 		policy->governor_data = NULL;
 	}
 
-	free_common_dbs_info(policy, cdata);
+	free_policy_dbs_info(policy_dbs, gov);
+
+	mutex_unlock(&gov_dbs_data_mutex);
 	return 0;
 }
 
-static int cpufreq_governor_start(struct cpufreq_policy *policy,
-				  struct dbs_data *dbs_data)
+static int cpufreq_governor_start(struct cpufreq_policy *policy)
 {
-	struct common_dbs_data *cdata = dbs_data->cdata;
-	unsigned int sampling_rate, ignore_nice, j, cpu = policy->cpu;
-	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
-	struct cpu_common_dbs_info *shared = cdbs->shared;
-	int io_busy = 0;
+	struct dbs_governor *gov = dbs_governor_of(policy);
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
+	struct dbs_data *dbs_data = policy_dbs->dbs_data;
+	unsigned int sampling_rate, ignore_nice, j;
+	unsigned int io_busy;
 
 	if (!policy->cur)
 		return -EINVAL;
 
-	/* State should be equivalent to INIT */
-	if (!shared || shared->policy)
-		return -EBUSY;
+	policy_dbs->is_shared = policy_is_shared(policy);
+	policy_dbs->rate_mult = 1;
 
-	if (cdata->governor == GOV_CONSERVATIVE) {
-		struct cs_dbs_tuners *cs_tuners = dbs_data->tuners;
-
-		sampling_rate = cs_tuners->sampling_rate;
-		ignore_nice = cs_tuners->ignore_nice_load;
-	} else {
-		struct od_dbs_tuners *od_tuners = dbs_data->tuners;
-
-		sampling_rate = od_tuners->sampling_rate;
-		ignore_nice = od_tuners->ignore_nice_load;
-		io_busy = od_tuners->io_is_busy;
-	}
-
-	shared->policy = policy;
-	shared->time_stamp = ktime_get();
+	sampling_rate = dbs_data->sampling_rate;
+	ignore_nice = dbs_data->ignore_nice_load;
+	io_busy = dbs_data->io_is_busy;
 
 	for_each_cpu(j, policy->cpus) {
-		struct cpu_dbs_info *j_cdbs = cdata->get_cpu_cdbs(j);
+		struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j);
 		unsigned int prev_load;
 
-		j_cdbs->prev_cpu_idle =
-			get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
+		j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
 
-		prev_load = (unsigned int)(j_cdbs->prev_cpu_wall -
-					    j_cdbs->prev_cpu_idle);
-		j_cdbs->prev_load = 100 * prev_load /
-				    (unsigned int)j_cdbs->prev_cpu_wall;
+		prev_load = j_cdbs->prev_cpu_wall - j_cdbs->prev_cpu_idle;
+		j_cdbs->prev_load = 100 * prev_load / (unsigned int)j_cdbs->prev_cpu_wall;
 
 		if (ignore_nice)
 			j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
-
-		__setup_timer(&j_cdbs->timer, dbs_timer_handler,
-			      (unsigned long)j_cdbs,
-			      TIMER_DEFERRABLE | TIMER_IRQSAFE);
 	}
 
-	if (cdata->governor == GOV_CONSERVATIVE) {
-		struct cs_cpu_dbs_info_s *cs_dbs_info =
-			cdata->get_cpu_dbs_info_s(cpu);
-
-		cs_dbs_info->down_skip = 0;
-		cs_dbs_info->requested_freq = policy->cur;
-	} else {
-		struct od_ops *od_ops = cdata->gov_ops;
-		struct od_cpu_dbs_info_s *od_dbs_info = cdata->get_cpu_dbs_info_s(cpu);
-
-		od_dbs_info->rate_mult = 1;
-		od_dbs_info->sample_type = OD_NORMAL_SAMPLE;
-		od_ops->powersave_bias_init_cpu(cpu);
-	}
+	gov->start(policy);
 
-	gov_add_timers(policy, delay_for_sampling_rate(sampling_rate));
+	gov_set_update_util(policy_dbs, sampling_rate);
 	return 0;
 }
 
-static int cpufreq_governor_stop(struct cpufreq_policy *policy,
-				 struct dbs_data *dbs_data)
+static int cpufreq_governor_stop(struct cpufreq_policy *policy)
 {
-	struct cpu_dbs_info *cdbs = dbs_data->cdata->get_cpu_cdbs(policy->cpu);
-	struct cpu_common_dbs_info *shared = cdbs->shared;
-
-	/* State should be equivalent to START */
-	if (!shared || !shared->policy)
-		return -EBUSY;
-
-	gov_cancel_work(shared);
-	shared->policy = NULL;
-
+	gov_cancel_work(policy);
 	return 0;
 }
 
-static int cpufreq_governor_limits(struct cpufreq_policy *policy,
-				   struct dbs_data *dbs_data)
+static int cpufreq_governor_limits(struct cpufreq_policy *policy)
 {
-	struct common_dbs_data *cdata = dbs_data->cdata;
-	unsigned int cpu = policy->cpu;
-	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
+	struct policy_dbs_info *policy_dbs = policy->governor_data;
 
-	/* State should be equivalent to START */
-	if (!cdbs->shared || !cdbs->shared->policy)
-		return -EBUSY;
+	mutex_lock(&policy_dbs->timer_mutex);
+
+	if (policy->max < policy->cur)
+		__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
+	else if (policy->min > policy->cur)
+		__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
+
+	gov_update_sample_delay(policy_dbs, 0);
 
-	mutex_lock(&cdbs->shared->timer_mutex);
-	if (policy->max < cdbs->shared->policy->cur)
-		__cpufreq_driver_target(cdbs->shared->policy, policy->max,
-					CPUFREQ_RELATION_H);
-	else if (policy->min > cdbs->shared->policy->cur)
-		__cpufreq_driver_target(cdbs->shared->policy, policy->min,
-					CPUFREQ_RELATION_L);
-	dbs_check_cpu(dbs_data, cpu);
-	mutex_unlock(&cdbs->shared->timer_mutex);
+	mutex_unlock(&policy_dbs->timer_mutex);
 
 	return 0;
 }
 
-int cpufreq_governor_dbs(struct cpufreq_policy *policy,
-			 struct common_dbs_data *cdata, unsigned int event)
+int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event)
 {
-	struct dbs_data *dbs_data;