cpufreq: Persist cpufreq time in state data across hotplug

Cpufreq time_in_state data for all CPUs is made persistent across
hotplug and exposed to userspace via sysfs file
/sys/devices/system/cpu/cpufreq/all_time_in_state

Change-Id: I97cb5de24b6de16189bf8b5df9592d0a6e6ddf32
Signed-off-by: Ruchi Kandoi <kandoiruchi@google.com>

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index 2ccfaed7d8441076f14a6e44c7e619a5067e411b..3f5e279ff9d8d6a8a9e43963bb5b9c2da8f16d4d 100644 (file)
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -20,6 +20,8 @@
 #include <linux/kobject.h>
 #include <linux/spinlock.h>
 #include <linux/notifier.h>
+#include <linux/sort.h>
+#include <linux/err.h>
 #include <asm/cputime.h>
 
 static spinlock_t cpufreq_stats_lock;
@@ -38,6 +40,20 @@ struct cpufreq_stats {
 #endif
 };
 
+struct all_cpufreq_stats {
+       unsigned int state_num;
+       cputime64_t *time_in_state;
+       unsigned int *freq_table;
+};
+
+struct all_freq_table {
+       unsigned int *freq_table;
+       unsigned int table_size;
+};
+
+static struct all_freq_table *all_freq_table;
+
+static DEFINE_PER_CPU(struct all_cpufreq_stats *, all_cpufreq_stats);
 static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
 
 struct cpufreq_stats_attribute {
@@ -48,14 +64,24 @@ struct cpufreq_stats_attribute {
 static int cpufreq_stats_update(unsigned int cpu)
 {
        struct cpufreq_stats *stat;
+       struct all_cpufreq_stats *all_stat;
        unsigned long long cur_time;
 
        cur_time = get_jiffies_64();
        spin_lock(&cpufreq_stats_lock);
        stat = per_cpu(cpufreq_stats_table, cpu);
-       if (stat->time_in_state)
+       all_stat = per_cpu(all_cpufreq_stats, cpu);
+       if (!stat) {
+               spin_unlock(&cpufreq_stats_lock);
+               return 0;
+       }
+       if (stat->time_in_state) {
                stat->time_in_state[stat->last_index] +=
                        cur_time - stat->last_time;
+               if (all_stat)
+                       all_stat->time_in_state[stat->last_index] +=
+                                       cur_time - stat->last_time;
+       }
        stat->last_time = cur_time;
        spin_unlock(&cpufreq_stats_lock);
        return 0;
@@ -86,6 +112,62 @@ static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
        return len;
 }
 
+static int get_index_all_cpufreq_stat(struct all_cpufreq_stats *all_stat,
+               unsigned int freq)
+{
+       int i;
+       if (!all_stat)
+               return -1;
+       for (i = 0; i < all_stat->state_num; i++) {
+               if (all_stat->freq_table[i] == freq)
+                       return i;
+       }
+       return -1;
+}
+
+static ssize_t show_all_time_in_state(struct kobject *kobj,
+               struct kobj_attribute *attr, char *buf)
+{
+       ssize_t len = 0;
+       unsigned int i, cpu, freq, index;
+       struct all_cpufreq_stats *all_stat;
+       struct cpufreq_policy *policy;
+
+       len += scnprintf(buf + len, PAGE_SIZE - len, "freq\t\t");
+       for_each_possible_cpu(cpu) {
+               len += scnprintf(buf + len, PAGE_SIZE - len, "cpu%d\t\t", cpu);
+               if (cpu_online(cpu))
+                       cpufreq_stats_update(cpu);
+       }
+
+       if (!all_freq_table)
+               goto out;
+       for (i = 0; i < all_freq_table->table_size; i++) {
+               freq = all_freq_table->freq_table[i];
+               len += scnprintf(buf + len, PAGE_SIZE - len, "\n%u\t\t", freq);
+               for_each_possible_cpu(cpu) {
+                       policy = cpufreq_cpu_get(cpu);
+                       if (policy == NULL)
+                               continue;
+                       all_stat = per_cpu(all_cpufreq_stats, policy->cpu);
+                       index = get_index_all_cpufreq_stat(all_stat, freq);
+                       if (index != -1) {
+                               len += scnprintf(buf + len, PAGE_SIZE - len,
+                                       "%llu\t\t", (unsigned long long)
+                                       cputime64_to_clock_t(all_stat->time_in_state[index]));
+                       } else {
+                               len += scnprintf(buf + len, PAGE_SIZE - len,
+                                               "N/A\t\t");
+                       }
+                       cpufreq_cpu_put(policy);
+               }
+       }
+
+out:
+       len += scnprintf(buf + len, PAGE_SIZE - len, "\n");
+       return len;
+}
+
 #ifdef CONFIG_CPU_FREQ_STAT_DETAILS
 static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
 {
@@ -149,6 +231,9 @@ static struct attribute_group stats_attr_group = {
        .name = "stats"
 };
 
+static struct kobj_attribute _attr_all_time_in_state = __ATTR(all_time_in_state,
+               0444, show_all_time_in_state, NULL);
+
 static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
 {
        int index;
@@ -195,6 +280,29 @@ put_ref:
        cpufreq_cpu_put(policy);
 }
 
+static void cpufreq_allstats_free(void)
+{
+       int i;
+       struct all_cpufreq_stats *all_stat;
+
+       sysfs_remove_file(cpufreq_global_kobject,
+                                               &_attr_all_time_in_state.attr);
+
+       for (i = 0; i < total_cpus; i++) {
+               all_stat = per_cpu(all_cpufreq_stats, i);
+               if (!all_stat)
+                       continue;
+               kfree(all_stat->time_in_state);
+               kfree(all_stat);
+               per_cpu(all_cpufreq_stats, i) = NULL;
+       }
+       if (all_freq_table) {
+               kfree(all_freq_table->freq_table);
+               kfree(all_freq_table);
+               all_freq_table = NULL;
+       }
+}
+
 static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
                struct cpufreq_frequency_table *table)
 {
@@ -281,6 +389,106 @@ static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
        stat->cpu = policy->cpu;
 }
 
+static int compare_for_sort(const void *lhs_ptr, const void *rhs_ptr)
+{
+       unsigned int lhs = *(const unsigned int *)(lhs_ptr);
+       unsigned int rhs = *(const unsigned int *)(rhs_ptr);
+       if (lhs < rhs)
+               return -1;
+       if (lhs > rhs)
+               return 1;
+       return 0;
+}
+
+static bool check_all_freq_table(unsigned int freq)
+{
+       int i;
+       for (i = 0; i < all_freq_table->table_size; i++) {
+               if (freq == all_freq_table->freq_table[i])
+                       return true;
+       }
+       return false;
+}
+
+static void create_all_freq_table(void)
+{
+       all_freq_table = kzalloc(sizeof(struct all_freq_table),
+                       GFP_KERNEL);
+       if (!all_freq_table)
+               pr_warn("could not allocate memory for all_freq_table\n");
+       return;
+}
+
+static void add_all_freq_table(unsigned int freq)
+{
+       unsigned int size;
+       size = sizeof(unsigned int) * (all_freq_table->table_size + 1);
+       all_freq_table->freq_table = krealloc(all_freq_table->freq_table,
+                       size, GFP_KERNEL);
+       if (IS_ERR(all_freq_table->freq_table)) {
+               pr_warn("Could not reallocate memory for freq_table\n");
+               all_freq_table->freq_table = NULL;
+               return;
+       }
+       all_freq_table->freq_table[all_freq_table->table_size++] = freq;
+}
+
+static void cpufreq_allstats_create(unsigned int cpu)
+{
+       int i , j = 0;
+       unsigned int alloc_size, count = 0;
+       struct cpufreq_frequency_table *table = cpufreq_frequency_get_table(cpu);
+       struct all_cpufreq_stats *all_stat;
+       bool sort_needed = false;
+
+       if (!table)
+               return;
+
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               unsigned int freq = table[i].frequency;
+               if (freq == CPUFREQ_ENTRY_INVALID)
+                       continue;
+               count++;
+       }
+
+       all_stat = kzalloc(sizeof(struct all_cpufreq_stats),
+                       GFP_KERNEL);
+       if (!all_stat) {
+               pr_warn("Cannot allocate memory for cpufreq stats\n");
+               return;
+       }
+
+       /*Allocate memory for freq table per cpu as well as clockticks per freq*/
+       alloc_size = count * sizeof(int) + count * sizeof(cputime64_t);
+       all_stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
+       if (!all_stat->time_in_state) {
+               pr_warn("Cannot allocate memory for cpufreq time_in_state\n");
+               kfree(all_stat);
+               all_stat = NULL;
+               return;
+       }
+       all_stat->freq_table = (unsigned int *)
+               (all_stat->time_in_state + count);
+
+       spin_lock(&cpufreq_stats_lock);
+       for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
+               unsigned int freq = table[i].frequency;
+               if (freq == CPUFREQ_ENTRY_INVALID)
+                       continue;
+               all_stat->freq_table[j++] = freq;
+               if (all_freq_table && !check_all_freq_table(freq)) {
+                       add_all_freq_table(freq);
+                       sort_needed = true;
+               }
+       }
+       if (sort_needed)
+               sort(all_freq_table->freq_table, all_freq_table->table_size,
+                               sizeof(unsigned int), &compare_for_sort, NULL);
+       all_stat->state_num = j;
+       per_cpu(all_cpufreq_stats, cpu) = all_stat;
+       spin_unlock(&cpufreq_stats_lock);
+}
+
 static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
                unsigned long val, void *data)
 {
@@ -299,6 +507,10 @@ static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
        table = cpufreq_frequency_get_table(cpu);
        if (!table)
                return 0;
+
+       if (!per_cpu(all_cpufreq_stats, cpu))
+               cpufreq_allstats_create(cpu);
+
        ret = cpufreq_stats_create_table(policy, table);
        if (ret)
                return ret;
@@ -355,6 +567,9 @@ static int cpufreq_stats_create_table_cpu(unsigned int cpu)
        if (!table)
                goto out;
 
+       if (!per_cpu(all_cpufreq_stats, cpu))
+               cpufreq_allstats_create(cpu);
+
        ret = cpufreq_stats_create_table(policy, table);
 
 out:
@@ -430,6 +645,12 @@ static int __init cpufreq_stats_init(void)
                return ret;
        }
 
+       create_all_freq_table();
+       ret = sysfs_create_file(cpufreq_global_kobject,
+                       &_attr_all_time_in_state.attr);
+       if (ret)
+               pr_warn("Error creating sysfs file for cpufreq stats\n");
+
        return 0;
 }
 static void __exit cpufreq_stats_exit(void)
@@ -445,6 +666,7 @@ static void __exit cpufreq_stats_exit(void)
                cpufreq_stats_free_table(cpu);
                cpufreq_stats_free_sysfs(cpu);
        }
+       cpufreq_allstats_free();
 }
 
 MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");