[PATCH 0/5] cpufreq: governor: Rework API to use callbacks instead of events

[PATCH 0/5] cpufreq: governor: Rework API to use callbacks instead of events

[Rafael J. Wysocki]

Hi,

This series is on top of the current linux-next witn the following two patches
applied:

https://patchwork.kernel.org/patch/9080801/
https://patchwork.kernel.org/patch/9080791/

It cleans up a few things and then reworks the governor API to get rid of
governor events and use callbacks representing individual governor operations
(init, exit, start, stop, limits update) instead.

I'm regarding it as v4.8 material, but I'd like to put it into linux-next as
soon as 4.7-rc1 is out so subsequent cpufreq development happens on top of it.

It has been lightly tested without any problems showing up so far.

Thanks,
Rafael

[PATCH 1/5] cpufreq: governor: CPUFREQ_GOV_LIMITS never fails

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

None of the cpufreq governors currently in the tree will ever fail
an invocation of the ->governor() callback with the event argument
equal to CPUFREQ_GOV_LIMITS (unless invoked with incorrect arguments
which doesn't matter anyway) and had it ever failed, the result of
it wouldn't have been very clean.

For this reason, rearrange the code in the core to ignore the return
value of cpufreq_governor() when called with event equal to
CPUFREQ_GOV_LIMITS.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq.c |    9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -2054,7 +2054,11 @@ static int cpufreq_start_governor(struct
 		cpufreq_update_current_freq(policy);
 
 	ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
-	return ret ? ret : cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+	if (ret)
+		return ret;
+
+	cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+	return 0;
 }
 
 int cpufreq_register_governor(struct cpufreq_governor *governor)
@@ -2195,7 +2199,8 @@ static int cpufreq_set_policy(struct cpu
 
 	if (new_policy->governor == policy->governor) {
 		pr_debug("cpufreq: governor limits update\n");
-		return cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+		cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+		return 0;
 	}
 
 	pr_debug("governor switch\n");

[PATCH 2/5] cpufreq: governor: Check transition latecy at init time only

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

It is not necessary to check the governor's max_transition_latency
attribute every time cpufreq_governor() runs, so check it only if
the event argument is CPUFREQ_GOV_POLICY_INIT.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq.c |   25 +++++++++++++------------
 1 file changed, 13 insertions(+), 12 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -2011,23 +2011,24 @@ static int cpufreq_governor(struct cpufr
 	if (!policy->governor)
 		return -EINVAL;
 
-	if (policy->governor->max_transition_latency &&
-	    policy->cpuinfo.transition_latency >
-	    policy->governor->max_transition_latency) {
-		struct cpufreq_governor *gov = cpufreq_fallback_governor();
+	if (event == CPUFREQ_GOV_POLICY_INIT) {
+		if (policy->governor->max_transition_latency &&
+		    policy->cpuinfo.transition_latency >
+		    policy->governor->max_transition_latency) {
+			struct cpufreq_governor *gov = cpufreq_fallback_governor();
 
-		if (gov) {
-			pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
-				policy->governor->name, gov->name);
-			policy->governor = gov;
-		} else {
-			return -EINVAL;
+			if (gov) {
+				pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
+					policy->governor->name, gov->name);
+				policy->governor = gov;
+			} else {
+				return -EINVAL;
+			}
 		}
-	}
 
-	if (event == CPUFREQ_GOV_POLICY_INIT)
 		if (!try_module_get(policy->governor->owner))
 			return -EINVAL;
+	}
 
 	pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
 

[PATCH 3/5] cpufreq: governor: Simplify performance and powersave governors

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The performance and powersave cpufreq governors handle the
CPUFREQ_GOV_START event in the same way as CPUFREQ_GOV_LIMITS.
However, the cpufreq core always invokes cpufreq_governor() with the
event argument equal to CPUFREQ_GOV_LIMITS right after invoking it with
event equal to CPUFREQ_GOV_START.  As a result, for both the governors
in question, __cpufreq_driver_target() is executed twice in a row
with the same arguments which is not useful.

For this reason, simplify the performance and powersave governors
to handle the CPUFREQ_GOV_LIMITS event only as that's going to be
sufficient for the governor start too.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq_performance.c |    4 +---
 drivers/cpufreq/cpufreq_powersave.c   |    4 +---
 2 files changed, 2 insertions(+), 6 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq_performance.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_performance.c
+++ linux-pm/drivers/cpufreq/cpufreq_performance.c
@@ -20,10 +20,8 @@ static int cpufreq_governor_performance(
 					unsigned int event)
 {
 	switch (event) {
-	case CPUFREQ_GOV_START:
 	case CPUFREQ_GOV_LIMITS:
-		pr_debug("setting to %u kHz because of event %u\n",
-						policy->max, event);
+		pr_debug("setting to %u kHz\n", policy->max);
 		__cpufreq_driver_target(policy, policy->max,
 						CPUFREQ_RELATION_H);
 		break;
Index: linux-pm/drivers/cpufreq/cpufreq_powersave.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_powersave.c
+++ linux-pm/drivers/cpufreq/cpufreq_powersave.c
@@ -20,10 +20,8 @@ static int cpufreq_governor_powersave(st
 					unsigned int event)
 {
 	switch (event) {
-	case CPUFREQ_GOV_START:
 	case CPUFREQ_GOV_LIMITS:
-		pr_debug("setting to %u kHz because of event %u\n",
-							policy->min, event);
+		pr_debug("setting to %u kHz\n", policy->min);
 		__cpufreq_driver_target(policy, policy->min,
 						CPUFREQ_RELATION_L);
 		break;

[PATCH 4/5] cpufreq: Split cpufreq_governor() into simpler functions

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The cpufreq_governor() routine is used by the cpufreq core to invoke
the current governor's ->governor() callback with appropriate arguments
and do some housekeeping related to that.  Unfortunately, the way it
mixes different governor events in one code path makes it rather hard
to follow the code.

For this reason, split cpufreq_governor() into five simpler functions
that each will handle just one specific governor event and put all of
the code related to the given event into its own function.

This change is a prerequisite for a redesign of the cpufreq governor
API that will be done subsequently.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq.c |  115 ++++++++++++++++++++++++++++------------------
 1 file changed, 71 insertions(+), 44 deletions(-)

Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -74,19 +74,12 @@ static inline bool has_target(void)
 }
 
 /* internal prototypes */
-static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event);
 static unsigned int __cpufreq_get(struct cpufreq_policy *policy);
+static int cpufreq_init_governor(struct cpufreq_policy *policy);
+static void cpufreq_exit_governor(struct cpufreq_policy *policy);
 static int cpufreq_start_governor(struct cpufreq_policy *policy);
-
-static inline void cpufreq_exit_governor(struct cpufreq_policy *policy)
-{
-	(void)cpufreq_governor(policy, CPUFREQ_GOV_POLICY_EXIT);
-}
-
-static inline void cpufreq_stop_governor(struct cpufreq_policy *policy)
-{
-	(void)cpufreq_governor(policy, CPUFREQ_GOV_STOP);
-}
+static void cpufreq_stop_governor(struct cpufreq_policy *policy);
+static void cpufreq_governor_limits(struct cpufreq_policy *policy);
 
 /**
  * Two notifier lists: the "policy" list is involved in the
@@ -1997,7 +1990,7 @@ __weak struct cpufreq_governor *cpufreq_
 	return NULL;
 }
 
-static int cpufreq_governor(struct cpufreq_policy *policy, unsigned int event)
+static int cpufreq_init_governor(struct cpufreq_policy *policy)
 {
 	int ret;
 
@@ -2011,57 +2004,91 @@ static int cpufreq_governor(struct cpufr
 	if (!policy->governor)
 		return -EINVAL;
 
-	if (event == CPUFREQ_GOV_POLICY_INIT) {
-		if (policy->governor->max_transition_latency &&
-		    policy->cpuinfo.transition_latency >
-		    policy->governor->max_transition_latency) {
-			struct cpufreq_governor *gov = cpufreq_fallback_governor();
-
-			if (gov) {
-				pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
-					policy->governor->name, gov->name);
-				policy->governor = gov;
-			} else {
-				return -EINVAL;
-			}
-		}
-
-		if (!try_module_get(policy->governor->owner))
+	if (policy->governor->max_transition_latency &&
+	    policy->cpuinfo.transition_latency >
+	    policy->governor->max_transition_latency) {
+		struct cpufreq_governor *gov = cpufreq_fallback_governor();
+
+		if (gov) {
+			pr_warn("%s governor failed, too long transition latency of HW, fallback to %s governor\n",
+				policy->governor->name, gov->name);
+			policy->governor = gov;
+		} else {
 			return -EINVAL;
+		}
 	}
 
-	pr_debug("%s: for CPU %u, event %u\n", __func__, policy->cpu, event);
+	if (!try_module_get(policy->governor->owner))
+		return -EINVAL;
 
-	ret = policy->governor->governor(policy, event);
+	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
 
-	if (event == CPUFREQ_GOV_POLICY_INIT) {
-		if (ret)
-			module_put(policy->governor->owner);
-		else
-			policy->governor->initialized++;
-	} else if (event == CPUFREQ_GOV_POLICY_EXIT) {
-		policy->governor->initialized--;
+	ret = policy->governor->governor(policy, CPUFREQ_GOV_POLICY_INIT);
+	if (ret) {
 		module_put(policy->governor->owner);
+		return ret;
 	}
 
-	return ret;
+	policy->governor->initialized++;
+	return 0;
+}
+
+static void cpufreq_exit_governor(struct cpufreq_policy *policy)
+{
+	if (cpufreq_suspended || !policy->governor)
+		return;
+
+	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
+
+	policy->governor->governor(policy, CPUFREQ_GOV_POLICY_EXIT);
+
+	policy->governor->initialized--;
+	module_put(policy->governor->owner);
 }
 
 static int cpufreq_start_governor(struct cpufreq_policy *policy)
 {
 	int ret;
 
+	if (cpufreq_suspended)
+		return 0;
+
+	if (!policy->governor)
+		return -EINVAL;
+
+	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
+
 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
 		cpufreq_update_current_freq(policy);
 
-	ret = cpufreq_governor(policy, CPUFREQ_GOV_START);
+	ret = policy->governor->governor(policy, CPUFREQ_GOV_START);
 	if (ret)
 		return ret;
 
-	cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+	policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
 	return 0;
 }
 
+static void cpufreq_stop_governor(struct cpufreq_policy *policy)
+{
+	if (cpufreq_suspended || !policy->governor)
+		return;
+
+	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
+
+	policy->governor->governor(policy, CPUFREQ_GOV_STOP);
+}
+
+static void cpufreq_governor_limits(struct cpufreq_policy *policy)
+{
+	if (cpufreq_suspended || !policy->governor)
+		return;
+
+	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
+
+	policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
+}
+
 int cpufreq_register_governor(struct cpufreq_governor *governor)
 {
 	int err;
@@ -2200,7 +2227,7 @@ static int cpufreq_set_policy(struct cpu
 
 	if (new_policy->governor == policy->governor) {
 		pr_debug("cpufreq: governor limits update\n");
-		cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+		cpufreq_governor_limits(policy);
 		return 0;
 	}
 
@@ -2216,7 +2243,7 @@ static int cpufreq_set_policy(struct cpu
 
 	/* start new governor */
 	policy->governor = new_policy->governor;
-	ret = cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT);
+	ret = cpufreq_init_governor(policy);
 	if (!ret) {
 		ret = cpufreq_start_governor(policy);
 		if (!ret) {
@@ -2230,7 +2257,7 @@ static int cpufreq_set_policy(struct cpu
 	pr_debug("starting governor %s failed\n", policy->governor->name);
 	if (old_gov) {
 		policy->governor = old_gov;
-		if (cpufreq_governor(policy, CPUFREQ_GOV_POLICY_INIT))
+		if (cpufreq_init_governor(policy))
 			policy->governor = NULL;
 		else
 			cpufreq_start_governor(policy);
@@ -2328,7 +2355,7 @@ static int cpufreq_boost_set_sw(int stat
 
 			down_write(&policy->rwsem);
 			policy->user_policy.max = policy->max;
-			cpufreq_governor(policy, CPUFREQ_GOV_LIMITS);
+			cpufreq_governor_limits(policy);
 			up_write(&policy->rwsem);
 		}
 	}

[PATCH 5/5] cpufreq: governor: Get rid of governor events

[Rafael J. Wysocki]

From: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

The design of the cpufreq governor API is not very straightforward,
as struct cpufreq_governor provides only one callback to be invoked
from different code paths for different purposes.  The purpose it is
invoked for is determined by its second "event" argument, causing it
to act as a "callback multiplexer" of sorts.

Unfortunately, that leads to extra complexity in governors, some of
which implement the ->governor() callback as a switch statement
that simply checks the event argument and invokes a separate function
to handle that specific event.

That extra complexity can be eliminated by replacing the all-purpose
->governor() callback with a family of callbacks to carry out specific
governor operations: initialization and exit, start and stop and policy
limits updates.  That also turns out to reduce the code size too, so
do it.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq.c              |   31 ++++++----
 drivers/cpufreq/cpufreq_conservative.c |    7 --
 drivers/cpufreq/cpufreq_governor.c     |   39 +++---------
 drivers/cpufreq/cpufreq_governor.h     |   20 ++++++
 drivers/cpufreq/cpufreq_ondemand.c     |    7 --
 drivers/cpufreq/cpufreq_performance.c  |   17 +----
 drivers/cpufreq/cpufreq_powersave.c    |   17 +----
 drivers/cpufreq/cpufreq_userspace.c    |  102 ++++++++++++++++-----------------
 include/linux/cpufreq.h                |   14 +---
 kernel/sched/cpufreq_schedutil.c       |   34 ++---------
 10 files changed, 123 insertions(+), 165 deletions(-)

Index: linux-pm/include/linux/cpufreq.h
===================================================================
--- linux-pm.orig/include/linux/cpufreq.h
+++ linux-pm/include/linux/cpufreq.h
@@ -455,18 +455,14 @@ static inline unsigned long cpufreq_scal
 #define MIN_LATENCY_MULTIPLIER		(20)
 #define TRANSITION_LATENCY_LIMIT	(10 * 1000 * 1000)
 
-/* Governor Events */
-#define CPUFREQ_GOV_START	1
-#define CPUFREQ_GOV_STOP	2
-#define CPUFREQ_GOV_LIMITS	3
-#define CPUFREQ_GOV_POLICY_INIT	4
-#define CPUFREQ_GOV_POLICY_EXIT	5
-
 struct cpufreq_governor {
 	char	name[CPUFREQ_NAME_LEN];
 	int	initialized;
-	int	(*governor)	(struct cpufreq_policy *policy,
-				 unsigned int event);
+	int	(*init)(struct cpufreq_policy *policy);
+	void	(*exit)(struct cpufreq_policy *policy);
+	int	(*start)(struct cpufreq_policy *policy);
+	void	(*stop)(struct cpufreq_policy *policy);
+	void	(*limits)(struct cpufreq_policy *policy);
 	ssize_t	(*show_setspeed)	(struct cpufreq_policy *policy,
 					 char *buf);
 	int	(*store_setspeed)	(struct cpufreq_policy *policy,
Index: linux-pm/drivers/cpufreq/cpufreq_governor.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
+++ linux-pm/drivers/cpufreq/cpufreq_governor.c
@@ -389,7 +389,7 @@ static void free_policy_dbs_info(struct
 	gov->free(policy_dbs);
 }
 
-static int cpufreq_governor_init(struct cpufreq_policy *policy)
+int cpufreq_dbs_governor_init(struct cpufreq_policy *policy)
 {
 	struct dbs_governor *gov = dbs_governor_of(policy);
 	struct dbs_data *dbs_data;
@@ -474,8 +474,9 @@ out:
 	mutex_unlock(&gov_dbs_data_mutex);
 	return ret;
 }
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_init);
 
-static int cpufreq_governor_exit(struct cpufreq_policy *policy)
+void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy)
 {
 	struct dbs_governor *gov = dbs_governor_of(policy);
 	struct policy_dbs_info *policy_dbs = policy->governor_data;
@@ -500,10 +501,10 @@ static int cpufreq_governor_exit(struct
 	free_policy_dbs_info(policy_dbs, gov);
 
 	mutex_unlock(&gov_dbs_data_mutex);
-	return 0;
 }
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_exit);
 
-static int cpufreq_governor_start(struct cpufreq_policy *policy)
+int cpufreq_dbs_governor_start(struct cpufreq_policy *policy)
 {
 	struct dbs_governor *gov = dbs_governor_of(policy);
 	struct policy_dbs_info *policy_dbs = policy->governor_data;
@@ -539,14 +540,15 @@ static int cpufreq_governor_start(struct
 	gov_set_update_util(policy_dbs, sampling_rate);
 	return 0;
 }
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_start);
 
-static int cpufreq_governor_stop(struct cpufreq_policy *policy)
+void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy)
 {
 	gov_cancel_work(policy);
-	return 0;
 }
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop);
 
-static int cpufreq_governor_limits(struct cpufreq_policy *policy)
+void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy)
 {
 	struct policy_dbs_info *policy_dbs = policy->governor_data;
 
@@ -560,26 +562,5 @@ static int cpufreq_governor_limits(struc
 	gov_update_sample_delay(policy_dbs, 0);
 
 	mutex_unlock(&policy_dbs->timer_mutex);
-
-	return 0;
-}
-
-int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event)
-{
-	if (event == CPUFREQ_GOV_POLICY_INIT) {
-		return cpufreq_governor_init(policy);
-	} else if (policy->governor_data) {
-		switch (event) {
-		case CPUFREQ_GOV_POLICY_EXIT:
-			return cpufreq_governor_exit(policy);
-		case CPUFREQ_GOV_START:
-			return cpufreq_governor_start(policy);
-		case CPUFREQ_GOV_STOP:
-			return cpufreq_governor_stop(policy);
-		case CPUFREQ_GOV_LIMITS:
-			return cpufreq_governor_limits(policy);
-		}
-	}
-	return -EINVAL;
 }
-EXPORT_SYMBOL_GPL(cpufreq_governor_dbs);
+EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);
Index: linux-pm/drivers/cpufreq/cpufreq_governor.h
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_governor.h
+++ linux-pm/drivers/cpufreq/cpufreq_governor.h
@@ -148,6 +148,25 @@ static inline struct dbs_governor *dbs_g
 	return container_of(policy->governor, struct dbs_governor, gov);
 }
 
+/* Governor callback routines */
+int cpufreq_dbs_governor_init(struct cpufreq_policy *policy);
+void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy);
+int cpufreq_dbs_governor_start(struct cpufreq_policy *policy);
+void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy);
+void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy);
+
+#define CPUFREQ_DBS_GOVERNOR_INITIALIZER(_name_)			\
+	{								\
+		.name = _name_,						\
+		.max_transition_latency	= TRANSITION_LATENCY_LIMIT,	\
+		.owner = THIS_MODULE,					\
+		.init = cpufreq_dbs_governor_init,			\
+		.exit = cpufreq_dbs_governor_exit,			\
+		.start = cpufreq_dbs_governor_start,			\
+		.stop = cpufreq_dbs_governor_stop,			\
+		.limits = cpufreq_dbs_governor_limits,			\
+	}
+
 /* Governor specific operations */
 struct od_ops {
 	unsigned int (*powersave_bias_target)(struct cpufreq_policy *policy,
@@ -155,7 +174,6 @@ struct od_ops {
 };
 
 unsigned int dbs_update(struct cpufreq_policy *policy);
-int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event);
 void od_register_powersave_bias_handler(unsigned int (*f)
 		(struct cpufreq_policy *, unsigned int, unsigned int),
 		unsigned int powersave_bias);
Index: linux-pm/drivers/cpufreq/cpufreq_ondemand.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_ondemand.c
+++ linux-pm/drivers/cpufreq/cpufreq_ondemand.c
@@ -420,12 +420,7 @@ static struct od_ops od_ops = {
 };
 
 static struct dbs_governor od_dbs_gov = {
-	.gov = {
-		.name = "ondemand",
-		.governor = cpufreq_governor_dbs,
-		.max_transition_latency	= TRANSITION_LATENCY_LIMIT,
-		.owner = THIS_MODULE,
-	},
+	.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("ondemand"),
 	.kobj_type = { .default_attrs = od_attributes },
 	.gov_dbs_timer = od_dbs_timer,
 	.alloc = od_alloc,
Index: linux-pm/drivers/cpufreq/cpufreq_conservative.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_conservative.c
+++ linux-pm/drivers/cpufreq/cpufreq_conservative.c
@@ -313,12 +313,7 @@ static void cs_start(struct cpufreq_poli
 }
 
 static struct dbs_governor cs_dbs_gov = {
-	.gov = {
-		.name = "conservative",
-		.governor = cpufreq_governor_dbs,
-		.max_transition_latency = TRANSITION_LATENCY_LIMIT,
-		.owner = THIS_MODULE,
-	},
+	.gov = CPUFREQ_DBS_GOVERNOR_INITIALIZER("conservative"),
 	.kobj_type = { .default_attrs = cs_attributes },
 	.gov_dbs_timer = cs_dbs_timer,
 	.alloc = cs_alloc,
Index: linux-pm/drivers/cpufreq/cpufreq_performance.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_performance.c
+++ linux-pm/drivers/cpufreq/cpufreq_performance.c
@@ -16,25 +16,16 @@
 #include <linux/init.h>
 #include <linux/module.h>
 
-static int cpufreq_governor_performance(struct cpufreq_policy *policy,
-					unsigned int event)
+static void cpufreq_gov_performance_limits(struct cpufreq_policy *policy)
 {
-	switch (event) {
-	case CPUFREQ_GOV_LIMITS:
-		pr_debug("setting to %u kHz\n", policy->max);
-		__cpufreq_driver_target(policy, policy->max,
-						CPUFREQ_RELATION_H);
-		break;
-	default:
-		break;
-	}
-	return 0;
+	pr_debug("setting to %u kHz\n", policy->max);
+	__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
 }
 
 static struct cpufreq_governor cpufreq_gov_performance = {
 	.name		= "performance",
-	.governor	= cpufreq_governor_performance,
 	.owner		= THIS_MODULE,
+	.limits		= cpufreq_gov_performance_limits,
 };
 
 static int __init cpufreq_gov_performance_init(void)
Index: linux-pm/drivers/cpufreq/cpufreq_powersave.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_powersave.c
+++ linux-pm/drivers/cpufreq/cpufreq_powersave.c
@@ -16,24 +16,15 @@
 #include <linux/init.h>
 #include <linux/module.h>
 
-static int cpufreq_governor_powersave(struct cpufreq_policy *policy,
-					unsigned int event)
+static void cpufreq_gov_powersave_limits(struct cpufreq_policy *policy)
 {
-	switch (event) {
-	case CPUFREQ_GOV_LIMITS:
-		pr_debug("setting to %u kHz\n", policy->min);
-		__cpufreq_driver_target(policy, policy->min,
-						CPUFREQ_RELATION_L);
-		break;
-	default:
-		break;
-	}
-	return 0;
+	pr_debug("setting to %u kHz\n", policy->min);
+	__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
 }
 
 static struct cpufreq_governor cpufreq_gov_powersave = {
 	.name		= "powersave",
-	.governor	= cpufreq_governor_powersave,
+	.limits		= cpufreq_gov_powersave_limits,
 	.owner		= THIS_MODULE,
 };
 
Index: linux-pm/drivers/cpufreq/cpufreq.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq.c
+++ linux-pm/drivers/cpufreq/cpufreq.c
@@ -2023,10 +2023,12 @@ static int cpufreq_init_governor(struct
 
 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
 
-	ret = policy->governor->governor(policy, CPUFREQ_GOV_POLICY_INIT);
-	if (ret) {
-		module_put(policy->governor->owner);
-		return ret;
+	if (policy->governor->init) {
+		ret = policy->governor->init(policy);
+		if (ret) {
+			module_put(policy->governor->owner);
+			return ret;
+		}
 	}
 
 	policy->governor->initialized++;
@@ -2040,7 +2042,8 @@ static void cpufreq_exit_governor(struct
 
 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
 
-	policy->governor->governor(policy, CPUFREQ_GOV_POLICY_EXIT);
+	if (policy->governor->exit)
+		policy->governor->exit(policy);
 
 	policy->governor->initialized--;
 	module_put(policy->governor->owner);
@@ -2061,11 +2064,15 @@ static int cpufreq_start_governor(struct
 	if (cpufreq_driver->get && !cpufreq_driver->setpolicy)
 		cpufreq_update_current_freq(policy);
 
-	ret = policy->governor->governor(policy, CPUFREQ_GOV_START);
-	if (ret)
-		return ret;
+	if (policy->governor->start) {
+		ret = policy->governor->start(policy);
+		if (ret)
+			return ret;
+	}
+
+	if (policy->governor->limits)
+		policy->governor->limits(policy);
 
-	policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
 	return 0;
 }
 
@@ -2076,7 +2083,8 @@ static void cpufreq_stop_governor(struct
 
 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
 
-	policy->governor->governor(policy, CPUFREQ_GOV_STOP);
+	if (policy->governor->stop)
+		policy->governor->stop(policy);
 }
 
 static void cpufreq_governor_limits(struct cpufreq_policy *policy)
@@ -2086,7 +2094,8 @@ static void cpufreq_governor_limits(stru
 
 	pr_debug("%s: for CPU %u\n", __func__, policy->cpu);
 
-	policy->governor->governor(policy, CPUFREQ_GOV_LIMITS);
+	if (policy->governor->limits)
+		policy->governor->limits(policy);
 }
 
 int cpufreq_register_governor(struct cpufreq_governor *governor)
Index: linux-pm/kernel/sched/cpufreq_schedutil.c
===================================================================
--- linux-pm.orig/kernel/sched/cpufreq_schedutil.c
+++ linux-pm/kernel/sched/cpufreq_schedutil.c
@@ -392,7 +392,7 @@ static int sugov_init(struct cpufreq_pol
 	return ret;
 }
 
-static int sugov_exit(struct cpufreq_policy *policy)
+static void sugov_exit(struct cpufreq_policy *policy)
 {
 	struct sugov_policy *sg_policy = policy->governor_data;
 	struct sugov_tunables *tunables = sg_policy->tunables;
@@ -410,7 +410,6 @@ static int sugov_exit(struct cpufreq_pol
 	mutex_unlock(&global_tunables_lock);
 
 	sugov_policy_free(sg_policy);
-	return 0;
 }
 
 static int sugov_start(struct cpufreq_policy *policy)
@@ -442,7 +441,7 @@ static int sugov_start(struct cpufreq_po
 	return 0;
 }
 
-static int sugov_stop(struct cpufreq_policy *policy)
+static void sugov_stop(struct cpufreq_policy *policy)
 {
 	struct sugov_policy *sg_policy = policy->governor_data;
 	unsigned int cpu;
@@ -454,10 +453,9 @@ static int sugov_stop(struct cpufreq_pol
 
 	irq_work_sync(&sg_policy->irq_work);
 	cancel_work_sync(&sg_policy->work);
-	return 0;
 }
 
-static int sugov_limits(struct cpufreq_policy *policy)
+static void sugov_limits(struct cpufreq_policy *policy)
 {
 	struct sugov_policy *sg_policy = policy->governor_data;
 
@@ -475,32 +473,16 @@ static int sugov_limits(struct cpufreq_p
 	}
 
 	sg_policy->need_freq_update = true;
-	return 0;
-}
-
-int sugov_governor(struct cpufreq_policy *policy, unsigned int event)
-{
-	if (event == CPUFREQ_GOV_POLICY_INIT) {
-		return sugov_init(policy);
-	} else if (policy->governor_data) {
-		switch (event) {
-		case CPUFREQ_GOV_POLICY_EXIT:
-			return sugov_exit(policy);
-		case CPUFREQ_GOV_START:
-			return sugov_start(policy);
-		case CPUFREQ_GOV_STOP:
-			return sugov_stop(policy);
-		case CPUFREQ_GOV_LIMITS:
-			return sugov_limits(policy);
-		}
-	}
-	return -EINVAL;
 }
 
 static struct cpufreq_governor schedutil_gov = {
 	.name = "schedutil",
-	.governor = sugov_governor,
 	.owner = THIS_MODULE,
+	.init = sugov_init,
+	.exit = sugov_exit,
+	.start = sugov_start,
+	.stop = sugov_stop,
+	.limits = sugov_limits,
 };
 
 static int __init sugov_module_init(void)
Index: linux-pm/drivers/cpufreq/cpufreq_userspace.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/cpufreq_userspace.c
+++ linux-pm/drivers/cpufreq/cpufreq_userspace.c
@@ -65,66 +65,66 @@ static int cpufreq_userspace_policy_init
 	return 0;
 }
 
-static int cpufreq_governor_userspace(struct cpufreq_policy *policy,
-				   unsigned int event)
+static void cpufreq_userspace_policy_exit(struct cpufreq_policy *policy)
+{
+	mutex_lock(&userspace_mutex);
+	kfree(policy->governor_data);
+	policy->governor_data = NULL;
+	mutex_unlock(&userspace_mutex);
+}
+
+static int cpufreq_userspace_policy_start(struct cpufreq_policy *policy)
 {
 	unsigned int *setspeed = policy->governor_data;
-	unsigned int cpu = policy->cpu;
-	int rc = 0;
 
-	if (event == CPUFREQ_GOV_POLICY_INIT)
-		return cpufreq_userspace_policy_init(policy);
+	BUG_ON(!policy->cur);
+	pr_debug("started managing cpu %u\n", policy->cpu);
+
+	mutex_lock(&userspace_mutex);
+	per_cpu(cpu_is_managed, policy->cpu) = 1;
+	*setspeed = policy->cur;
+	mutex_unlock(&userspace_mutex);
+	return 0;
+}
+
+static void cpufreq_userspace_policy_stop(struct cpufreq_policy *policy)
+{
+	unsigned int *setspeed = policy->governor_data;
+
+	pr_debug("managing cpu %u stopped\n", policy->cpu);
+
+	mutex_lock(&userspace_mutex);
+	per_cpu(cpu_is_managed, policy->cpu) = 0;
+	*setspeed = 0;
+	mutex_unlock(&userspace_mutex);
+}
+
+static void cpufreq_userspace_policy_limits(struct cpufreq_policy *policy)
+{
+	unsigned int *setspeed = policy->governor_data;
+
+	mutex_lock(&userspace_mutex);
+
+	pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
+		 policy->cpu, policy->min, policy->max, policy->cur, *setspeed);
 
-	if (!setspeed)
-		return -EINVAL;
+	if (policy->max < *setspeed)
+		__cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);
+	else if (policy->min > *setspeed)
+		__cpufreq_driver_target(policy, policy->min, CPUFREQ_RELATION_L);
+	else
+		__cpufreq_driver_target(policy, *setspeed, CPUFREQ_RELATION_L);
 
-	switch (event) {
-	case CPUFREQ_GOV_POLICY_EXIT:
-		mutex_lock(&userspace_mutex);
-		policy->governor_data = NULL;
-		kfree(setspeed);
-		mutex_unlock(&userspace_mutex);
-		break;
-	case CPUFREQ_GOV_START:
-		BUG_ON(!policy->cur);
-		pr_debug("started managing cpu %u\n", cpu);
-
-		mutex_lock(&userspace_mutex);
-		per_cpu(cpu_is_managed, cpu) = 1;
-		*setspeed = policy->cur;
-		mutex_unlock(&userspace_mutex);
-		break;
-	case CPUFREQ_GOV_STOP:
-		pr_debug("managing cpu %u stopped\n", cpu);
-
-		mutex_lock(&userspace_mutex);
-		per_cpu(cpu_is_managed, cpu) = 0;
-		*setspeed = 0;
-		mutex_unlock(&userspace_mutex);
-		break;
-	case CPUFREQ_GOV_LIMITS:
-		mutex_lock(&userspace_mutex);
-		pr_debug("limit event for cpu %u: %u - %u kHz, currently %u kHz, last set to %u kHz\n",
-			cpu, policy->min, policy->max, policy->cur, *setspeed);
-
-		if (policy->max < *setspeed)
-			__cpufreq_driver_target(policy, policy->max,
-						CPUFREQ_RELATION_H);
-		else if (policy->min > *setspeed)
-			__cpufreq_driver_target(policy, policy->min,
-						CPUFREQ_RELATION_L);
-		else
-			__cpufreq_driver_target(policy, *setspeed,
-						CPUFREQ_RELATION_L);
-		mutex_unlock(&userspace_mutex);
-		break;
-	}
-	return rc;
+	mutex_unlock(&userspace_mutex);
 }
 
 static struct cpufreq_governor cpufreq_gov_userspace = {
 	.name		= "userspace",
-	.governor	= cpufreq_governor_userspace,
+	.init		= cpufreq_userspace_policy_init,
+	.exit		= cpufreq_userspace_policy_exit,
+	.start		= cpufreq_userspace_policy_start,
+	.stop		= cpufreq_userspace_policy_stop,
+	.limits		= cpufreq_userspace_policy_limits,
 	.store_setspeed	= cpufreq_set,
 	.show_setspeed	= show_speed,
 	.owner		= THIS_MODULE,

Re: [PATCH 5/5] cpufreq: governor: Get rid of governor events

[Viresh Kumar]

On 14-05-16, 01:02, Rafael J. Wysocki wrote:
> --- linux-pm.orig/drivers/cpufreq/cpufreq_governor.c
> -int cpufreq_governor_dbs(struct cpufreq_policy *policy, unsigned int event)
> -{
> -	if (event == CPUFREQ_GOV_POLICY_INIT) {
> -		return cpufreq_governor_init(policy);
> -	} else if (policy->governor_data) {

So, we aren't checking this anymore.

I am not sure (right now) if this will be a problem.

-- 
viresh

Re: [PATCH 0/5] cpufreq: governor: Rework API to use callbacks instead of events

[Viresh Kumar]

On 14-05-16, 00:58, Rafael J. Wysocki wrote:
> Hi,
> 
> This series is on top of the current linux-next witn the following two patches
> applied:
> 
> https://patchwork.kernel.org/patch/9080801/
> https://patchwork.kernel.org/patch/9080791/
> 
> It cleans up a few things and then reworks the governor API to get rid of
> governor events and use callbacks representing individual governor operations
> (init, exit, start, stop, limits update) instead.
> 
> I'm regarding it as v4.8 material, but I'd like to put it into linux-next as
> soon as 4.7-rc1 is out so subsequent cpufreq development happens on top of it.
> 
> It has been lightly tested without any problems showing up so far.

Acked-by: Viresh Kumar <viresh.kumar@linaro.org>

-- 
viresh