cpufreq: stats: get rid of per-cpu cpufreq_stats_table

All CPUs sharing a cpufreq policy share stats too. For this reason,
add a stats pointer to struct cpufreq_policy and drop per-CPU variable
cpufreq_stats_table used for accessing cpufreq stats so as to reduce
code complexity.

Reviewed-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

1 files changed, 29 insertions, 33 deletions

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 6c234f548601..3792b2e2f4a8 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -31,8 +31,6 @@ struct cpufreq_stats {
 #endif
 };
 
-static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
-
 static int cpufreq_stats_update(struct cpufreq_stats *stat)
 {
         unsigned long long cur_time = get_jiffies_64();
@@ -48,20 +46,15 @@ static int cpufreq_stats_update(struct cpufreq_stats *stat)
 
 static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
 {
-        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
-        if (!stat)
-                return 0;
-        return sprintf(buf, "%d\n",
-                        per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
+        return sprintf(buf, "%d\n", policy->stats->total_trans);
 }
 
 static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
 {
+        struct cpufreq_stats *stat = policy->stats;
         ssize_t len = 0;
         int i;
-        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
-        if (!stat)
-                return 0;
+
         cpufreq_stats_update(stat);
         for (i = 0; i < stat->state_num; i++) {
                 len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
@@ -74,12 +67,10 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 {
+        struct cpufreq_stats *stat = policy->stats;
         ssize_t len = 0;
         int i, j;
 
-        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
-        if (!stat)
-                return 0;
         cpufreq_stats_update(stat);
         len += snprintf(buf + len, PAGE_SIZE - len, "   From  :    To\n");
         len += snprintf(buf + len, PAGE_SIZE - len, "         : ");
@@ -145,8 +136,9 @@ static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 
 static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
 {
-        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
+        struct cpufreq_stats *stat = policy->stats;
 
+        /* Already freed */
         if (!stat)
                 return;
 
@@ -155,7 +147,7 @@ static void __cpufreq_stats_free_table(struct cpufreq_policy *policy)
         sysfs_remove_group(&policy->kobj, &stats_attr_group);
         kfree(stat->time_in_state);
         kfree(stat);
-        per_cpu(cpufreq_stats_table, policy->cpu) = NULL;
+        policy->stats = NULL;
 }
 
 static void cpufreq_stats_free_table(unsigned int cpu)
@@ -184,7 +176,7 @@ static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
                 return 0;
 
         /* stats already initialized */
-        if (per_cpu(cpufreq_stats_table, cpu))
+        if (policy->stats)
                 return -EEXIST;
 
         stat = kzalloc(sizeof(*stat), GFP_KERNEL);
@@ -196,7 +188,7 @@ static int __cpufreq_stats_create_table(struct cpufreq_policy *policy)
                 goto error_out;
 
         stat->cpu = cpu;
-        per_cpu(cpufreq_stats_table, cpu) = stat;
+        policy->stats = stat;
 
         cpufreq_for_each_valid_entry(pos, table)
                 count++;
@@ -231,7 +223,7 @@ error_alloc:
         sysfs_remove_group(&policy->kobj, &stats_attr_group);
 error_out:
         kfree(stat);
-        per_cpu(cpufreq_stats_table, cpu) = NULL;
+        policy->stats = NULL;
         return ret;
 }
 
@@ -254,15 +246,7 @@ static void cpufreq_stats_create_table(unsigned int cpu)
 
 static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
 {
-        struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
-                        policy->last_cpu);
-
-        pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
-                        policy->cpu, policy->last_cpu);
-        per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
-                        policy->last_cpu);
-        per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
-        stat->cpu = policy->cpu;
+        policy->stats->cpu = policy->cpu;
 }
 
 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
@@ -288,27 +272,36 @@ static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
                 unsigned long val, void *data)
 {
         struct cpufreq_freqs *freq = data;
+        struct cpufreq_policy *policy = cpufreq_cpu_get(freq->cpu);
         struct cpufreq_stats *stat;
         int old_index, new_index;
 
-        if (val != CPUFREQ_POSTCHANGE)
+        if (!policy) {
+                pr_err("%s: No policy found\n", __func__);
                 return 0;
+        }
 
-        stat = per_cpu(cpufreq_stats_table, freq->cpu);
-        if (!stat)
-                return 0;
+        if (val != CPUFREQ_POSTCHANGE)
+                goto put_policy;
+
+        if (!policy->stats) {
+                pr_debug("%s: No stats found\n", __func__);
+                goto put_policy;
+        }
+
+        stat = policy->stats;
 
         old_index = stat->last_index;
         new_index = freq_table_get_index(stat, freq->new);
 
         /* We can't do stat->time_in_state[-1]= .. */
         if (old_index == -1 || new_index == -1)
-                return 0;
+                goto put_policy;
 
         cpufreq_stats_update(stat);
 
         if (old_index == new_index)
-                return 0;
+                goto put_policy;
 
         spin_lock(&cpufreq_stats_lock);
         stat->last_index = new_index;
@@ -317,6 +310,9 @@ static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
 #endif
         stat->total_trans++;
         spin_unlock(&cpufreq_stats_lock);
+
+put_policy:
+        cpufreq_cpu_put(policy);
         return 0;
 }