cpufreq: governor: Keep single copy of information common to policy->cpus

Some information is common to all CPUs belonging to a policy, but are
kept on per-cpu basis. Lets keep that in another structure common to all
policy->cpus. That will make updates/reads to that less complex and less
error prone.

The memory for cpu_common_dbs_info is allocated/freed at INIT/EXIT, so
that it we don't reallocate it for STOP/START sequence. It will be also
be used (in next patch) while the governor is stopped and so must not be
freed that early.

Reviewed-and-tested-by: Preeti U Murthy <preeti@linux.vnet.ibm.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 68 insertions, 24 deletions

diff --git a/drivers/cpufreq/cpufreq_governor.c b/drivers/cpufreq/cpufreq_governor.c
index c0566f86caed..b01cb729104b 100644
--- a/drivers/cpufreq/cpufreq_governor.c
+++ b/drivers/cpufreq/cpufreq_governor.c
@@ -35,7 +35,7 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 	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;
+	struct cpufreq_policy *policy = cdbs->shared->policy;
 	unsigned int sampling_rate;
 	unsigned int max_load = 0;
 	unsigned int ignore_nice;
@@ -60,8 +60,6 @@ void dbs_check_cpu(struct dbs_data *dbs_data, int cpu)
 		ignore_nice = cs_tuners->ignore_nice_load;
 	}
 
-	policy = cdbs->policy;
-
 	/* Get Absolute Load */
 	for_each_cpu(j, policy->cpus) {
 		struct cpu_dbs_info *j_cdbs;
@@ -209,17 +207,18 @@ static inline void gov_cancel_work(struct dbs_data *dbs_data,
 }
 
 /* Will return if we need to evaluate cpu load again or not */
-bool need_load_eval(struct cpu_dbs_info *cdbs, unsigned int sampling_rate)
+bool need_load_eval(struct cpu_common_dbs_info *shared,
+		    unsigned int sampling_rate)
 {
-	if (policy_is_shared(cdbs->policy)) {
+	if (policy_is_shared(shared->policy)) {
 		ktime_t time_now = ktime_get();
-		s64 delta_us = ktime_us_delta(time_now, cdbs->time_stamp);
+		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
-			cdbs->time_stamp = time_now;
+			shared->time_stamp = time_now;
 	}
 
 	return true;
@@ -238,6 +237,37 @@ static void set_sampling_rate(struct dbs_data *dbs_data,
 	}
 }
 
+static int alloc_common_dbs_info(struct cpufreq_policy *policy,
+				 struct common_dbs_data *cdata)
+{
+	struct cpu_common_dbs_info *shared;
+	int j;
+
+	/* Allocate memory for the common information for policy->cpus */
+	shared = kzalloc(sizeof(*shared), GFP_KERNEL);
+	if (!shared)
+		return -ENOMEM;
+
+	/* Set shared for all CPUs, online+offline */
+	for_each_cpu(j, policy->related_cpus)
+		cdata->get_cpu_cdbs(j)->shared = shared;
+
+	return 0;
+}
+
+static void free_common_dbs_info(struct cpufreq_policy *policy,
+				 struct common_dbs_data *cdata)
+{
+	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(policy->cpu);
+	struct cpu_common_dbs_info *shared = cdbs->shared;
+	int j;
+
+	for_each_cpu(j, policy->cpus)
+		cdata->get_cpu_cdbs(j)->shared = NULL;
+
+	kfree(shared);
+}
+
 static int cpufreq_governor_init(struct cpufreq_policy *policy,
 				 struct dbs_data *dbs_data,
 				 struct common_dbs_data *cdata)
@@ -248,6 +278,11 @@ static int cpufreq_governor_init(struct cpufreq_policy *policy,
 	if (dbs_data) {
 		if (WARN_ON(have_governor_per_policy()))
 			return -EINVAL;
+
+		ret = alloc_common_dbs_info(policy, cdata);
+		if (ret)
+			return ret;
+
 		dbs_data->usage_count++;
 		policy->governor_data = dbs_data;
 		return 0;
@@ -257,12 +292,16 @@ static int cpufreq_governor_init(struct cpufreq_policy *policy,
 	if (!dbs_data)
 		return -ENOMEM;
 
+	ret = alloc_common_dbs_info(policy, cdata);
+	if (ret)
+		goto free_dbs_data;
+
 	dbs_data->cdata = cdata;
 	dbs_data->usage_count = 1;
 
 	ret = cdata->init(dbs_data, !policy->governor->initialized);
 	if (ret)
-		goto free_dbs_data;
+		goto free_common_dbs_info;
 
 	/* policy latency is in ns. Convert it to us first */
 	latency = policy->cpuinfo.transition_latency / 1000;
@@ -299,6 +338,8 @@ put_kobj:
 	}
 cdata_exit:
 	cdata->exit(dbs_data, !policy->governor->initialized);
+free_common_dbs_info:
+	free_common_dbs_info(policy, cdata);
 free_dbs_data:
 	kfree(dbs_data);
 	return ret;
@@ -322,6 +363,8 @@ static void cpufreq_governor_exit(struct cpufreq_policy *policy,
 		cdata->exit(dbs_data, policy->governor->initialized == 1);
 		kfree(dbs_data);
 	}
+
+	free_common_dbs_info(policy, cdata);
 }
 
 static int cpufreq_governor_start(struct cpufreq_policy *policy,
@@ -330,6 +373,7 @@ 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;
 
 	if (!policy->cur)
@@ -348,11 +392,14 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
 		io_busy = od_tuners->io_is_busy;
 	}
 
+	shared->policy = policy;
+	shared->time_stamp = ktime_get();
+	mutex_init(&shared->timer_mutex);
+
 	for_each_cpu(j, policy->cpus) {
 		struct cpu_dbs_info *j_cdbs = cdata->get_cpu_cdbs(j);
 		unsigned int prev_load;
 
-		j_cdbs->policy = policy;
 		j_cdbs->prev_cpu_idle =
 			get_cpu_idle_time(j, &j_cdbs->prev_cpu_wall, io_busy);
 
@@ -364,7 +411,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
 		if (ignore_nice)
 			j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE];
 
-		mutex_init(&j_cdbs->timer_mutex);
 		INIT_DEFERRABLE_WORK(&j_cdbs->dwork, cdata->gov_dbs_timer);
 	}
 
@@ -384,9 +430,6 @@ static int cpufreq_governor_start(struct cpufreq_policy *policy,
 		od_ops->powersave_bias_init_cpu(cpu);
 	}
 
-	/* Initiate timer time stamp */
-	cdbs->time_stamp = ktime_get();
-
 	gov_queue_work(dbs_data, policy, delay_for_sampling_rate(sampling_rate),
 		       true);
 	return 0;
@@ -398,6 +441,9 @@ static void cpufreq_governor_stop(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 cpu_common_dbs_info *shared = cdbs->shared;
+
+	gov_cancel_work(dbs_data, policy);
 
 	if (cdata->governor == GOV_CONSERVATIVE) {
 		struct cs_cpu_dbs_info_s *cs_dbs_info =
@@ -406,10 +452,8 @@ static void cpufreq_governor_stop(struct cpufreq_policy *policy,
 		cs_dbs_info->enable = 0;
 	}
 
-	gov_cancel_work(dbs_data, policy);
-
-	mutex_destroy(&cdbs->timer_mutex);
-	cdbs->policy = NULL;
+	shared->policy = NULL;
+	mutex_destroy(&shared->timer_mutex);
 }
 
 static void cpufreq_governor_limits(struct cpufreq_policy *policy,
@@ -419,18 +463,18 @@ static void cpufreq_governor_limits(struct cpufreq_policy *policy,
 	unsigned int cpu = policy->cpu;
 	struct cpu_dbs_info *cdbs = cdata->get_cpu_cdbs(cpu);
 
-	if (!cdbs->policy)
+	if (!cdbs->shared || !cdbs->shared->policy)
 		return;
 
-	mutex_lock(&cdbs->timer_mutex);
-	if (policy->max < cdbs->policy->cur)
-		__cpufreq_driver_target(cdbs->policy, policy->max,
+	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->policy->cur)
-		__cpufreq_driver_target(cdbs->policy, policy->min,
+	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->timer_mutex);
+	mutex_unlock(&cdbs->shared->timer_mutex);
 }
 
 int cpufreq_governor_dbs(struct cpufreq_policy *policy,