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>

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 6c234f5..3792b2e 100644 (file)
--- 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;
 }
 

diff --git a/include/linux/cpufreq.h b/include/linux/cpufreq.h
index 4d078ce..60b7b49 100644 (file)
--- a/include/linux/cpufreq.h
+++ b/include/linux/cpufreq.h
@@ -113,6 +113,9 @@ struct cpufreq_policy {
        wait_queue_head_t       transition_wait;
        struct task_struct      *transition_task; /* Task which is doing the transition */
 
+       /* cpufreq-stats */
+       struct cpufreq_stats    *stats;
+
        /* For cpufreq driver's internal use */
        void                    *driver_data;
 };