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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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a857c0b9e2
The time spent by a CPU under a given frequency is stored in jiffies unit
in the cpu var cpufreq_stats_table->time_in_state[i], i being the index of
the frequency.
This is what is displayed in the following file on the right column:
cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
2301000 19835820
2300000 3172
[...]
Now cpufreq converts this jiffies unit delta to clock_t before returning it
to the user as in the above file. And that conversion is achieved using the API
cputime64_to_clock_t().
Although it accidentally works on traditional tick based cputime accounting, where
cputime_t maps directly to jiffies, it doesn't work with other types of cputime
accounting such as CONFIG_VIRT_CPU_ACCOUNTING_* where cputime_t can map to nsecs
or any granularity preffered by the architecture.
For example we get a buggy zero delta on full dyntick configurations:
cat /sys/devices/system/cpu/cpuX/cpufreq/stats/time_in_state
2301000 0
2300000 0
[...]
Fix this with using the proper jiffies_64_t to clock_t conversion.
Reported-and-tested-by: Carsten Emde <C.Emde@osadl.org>
Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
416 lines
10 KiB
C
416 lines
10 KiB
C
/*
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* drivers/cpufreq/cpufreq_stats.c
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*
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* Copyright (C) 2003-2004 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>.
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* (C) 2004 Zou Nan hai <nanhai.zou@intel.com>.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/cpu.h>
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#include <linux/cpufreq.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <asm/cputime.h>
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static spinlock_t cpufreq_stats_lock;
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struct cpufreq_stats {
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unsigned int cpu;
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unsigned int total_trans;
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unsigned long long last_time;
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unsigned int max_state;
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unsigned int state_num;
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unsigned int last_index;
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u64 *time_in_state;
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unsigned int *freq_table;
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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unsigned int *trans_table;
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#endif
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};
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static DEFINE_PER_CPU(struct cpufreq_stats *, cpufreq_stats_table);
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struct cpufreq_stats_attribute {
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struct attribute attr;
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ssize_t(*show) (struct cpufreq_stats *, char *);
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};
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static int cpufreq_stats_update(unsigned int cpu)
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{
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struct cpufreq_stats *stat;
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unsigned long long cur_time;
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cur_time = get_jiffies_64();
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spin_lock(&cpufreq_stats_lock);
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stat = per_cpu(cpufreq_stats_table, cpu);
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if (stat->time_in_state)
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stat->time_in_state[stat->last_index] +=
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cur_time - stat->last_time;
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stat->last_time = cur_time;
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spin_unlock(&cpufreq_stats_lock);
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return 0;
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}
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static ssize_t show_total_trans(struct cpufreq_policy *policy, char *buf)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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return sprintf(buf, "%d\n",
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per_cpu(cpufreq_stats_table, stat->cpu)->total_trans);
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}
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static ssize_t show_time_in_state(struct cpufreq_policy *policy, char *buf)
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{
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ssize_t len = 0;
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int i;
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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cpufreq_stats_update(stat->cpu);
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for (i = 0; i < stat->state_num; i++) {
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len += sprintf(buf + len, "%u %llu\n", stat->freq_table[i],
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(unsigned long long)
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jiffies_64_to_clock_t(stat->time_in_state[i]));
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}
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return len;
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}
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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static ssize_t show_trans_table(struct cpufreq_policy *policy, char *buf)
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{
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ssize_t len = 0;
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int i, j;
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, policy->cpu);
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if (!stat)
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return 0;
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cpufreq_stats_update(stat->cpu);
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len += snprintf(buf + len, PAGE_SIZE - len, " From : To\n");
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len += snprintf(buf + len, PAGE_SIZE - len, " : ");
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for (i = 0; i < stat->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
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stat->freq_table[i]);
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}
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if (len >= PAGE_SIZE)
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return PAGE_SIZE;
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len += snprintf(buf + len, PAGE_SIZE - len, "\n");
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for (i = 0; i < stat->state_num; i++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u: ",
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stat->freq_table[i]);
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for (j = 0; j < stat->state_num; j++) {
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "%9u ",
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stat->trans_table[i*stat->max_state+j]);
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}
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if (len >= PAGE_SIZE)
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break;
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len += snprintf(buf + len, PAGE_SIZE - len, "\n");
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}
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if (len >= PAGE_SIZE)
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return PAGE_SIZE;
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return len;
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}
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cpufreq_freq_attr_ro(trans_table);
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#endif
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cpufreq_freq_attr_ro(total_trans);
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cpufreq_freq_attr_ro(time_in_state);
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static struct attribute *default_attrs[] = {
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&total_trans.attr,
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&time_in_state.attr,
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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&trans_table.attr,
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#endif
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NULL
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};
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static struct attribute_group stats_attr_group = {
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.attrs = default_attrs,
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.name = "stats"
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};
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static int freq_table_get_index(struct cpufreq_stats *stat, unsigned int freq)
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{
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int index;
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for (index = 0; index < stat->max_state; index++)
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if (stat->freq_table[index] == freq)
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return index;
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return -1;
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}
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/* should be called late in the CPU removal sequence so that the stats
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* memory is still available in case someone tries to use it.
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*/
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static void cpufreq_stats_free_table(unsigned int cpu)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table, cpu);
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if (stat) {
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pr_debug("%s: Free stat table\n", __func__);
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kfree(stat->time_in_state);
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kfree(stat);
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per_cpu(cpufreq_stats_table, cpu) = NULL;
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}
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}
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/* must be called early in the CPU removal sequence (before
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* cpufreq_remove_dev) so that policy is still valid.
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*/
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static void cpufreq_stats_free_sysfs(unsigned int cpu)
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{
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struct cpufreq_policy *policy = cpufreq_cpu_get(cpu);
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if (!policy)
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return;
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if (!cpufreq_frequency_get_table(cpu))
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goto put_ref;
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if (!policy_is_shared(policy)) {
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pr_debug("%s: Free sysfs stat\n", __func__);
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sysfs_remove_group(&policy->kobj, &stats_attr_group);
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}
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put_ref:
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cpufreq_cpu_put(policy);
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}
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static int cpufreq_stats_create_table(struct cpufreq_policy *policy,
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struct cpufreq_frequency_table *table)
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{
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unsigned int i, j, count = 0, ret = 0;
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struct cpufreq_stats *stat;
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struct cpufreq_policy *current_policy;
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unsigned int alloc_size;
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unsigned int cpu = policy->cpu;
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if (per_cpu(cpufreq_stats_table, cpu))
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return -EBUSY;
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stat = kzalloc(sizeof(*stat), GFP_KERNEL);
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if ((stat) == NULL)
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return -ENOMEM;
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current_policy = cpufreq_cpu_get(cpu);
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if (current_policy == NULL) {
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ret = -EINVAL;
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goto error_get_fail;
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}
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ret = sysfs_create_group(¤t_policy->kobj, &stats_attr_group);
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if (ret)
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goto error_out;
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stat->cpu = cpu;
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per_cpu(cpufreq_stats_table, cpu) = stat;
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for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
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unsigned int freq = table[i].frequency;
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if (freq == CPUFREQ_ENTRY_INVALID)
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continue;
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count++;
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}
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alloc_size = count * sizeof(int) + count * sizeof(u64);
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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alloc_size += count * count * sizeof(int);
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#endif
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stat->max_state = count;
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stat->time_in_state = kzalloc(alloc_size, GFP_KERNEL);
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if (!stat->time_in_state) {
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ret = -ENOMEM;
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goto error_out;
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}
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stat->freq_table = (unsigned int *)(stat->time_in_state + count);
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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stat->trans_table = stat->freq_table + count;
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#endif
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j = 0;
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for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
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unsigned int freq = table[i].frequency;
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if (freq == CPUFREQ_ENTRY_INVALID)
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continue;
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if (freq_table_get_index(stat, freq) == -1)
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stat->freq_table[j++] = freq;
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}
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stat->state_num = j;
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spin_lock(&cpufreq_stats_lock);
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stat->last_time = get_jiffies_64();
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stat->last_index = freq_table_get_index(stat, policy->cur);
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spin_unlock(&cpufreq_stats_lock);
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cpufreq_cpu_put(current_policy);
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return 0;
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error_out:
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cpufreq_cpu_put(current_policy);
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error_get_fail:
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kfree(stat);
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per_cpu(cpufreq_stats_table, cpu) = NULL;
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return ret;
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}
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static void cpufreq_stats_update_policy_cpu(struct cpufreq_policy *policy)
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{
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struct cpufreq_stats *stat = per_cpu(cpufreq_stats_table,
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policy->last_cpu);
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pr_debug("Updating stats_table for new_cpu %u from last_cpu %u\n",
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policy->cpu, policy->last_cpu);
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per_cpu(cpufreq_stats_table, policy->cpu) = per_cpu(cpufreq_stats_table,
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policy->last_cpu);
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per_cpu(cpufreq_stats_table, policy->last_cpu) = NULL;
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stat->cpu = policy->cpu;
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}
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static int cpufreq_stat_notifier_policy(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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int ret;
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struct cpufreq_policy *policy = data;
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struct cpufreq_frequency_table *table;
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unsigned int cpu = policy->cpu;
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if (val == CPUFREQ_UPDATE_POLICY_CPU) {
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cpufreq_stats_update_policy_cpu(policy);
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return 0;
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}
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if (val != CPUFREQ_NOTIFY)
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return 0;
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table = cpufreq_frequency_get_table(cpu);
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if (!table)
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return 0;
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ret = cpufreq_stats_create_table(policy, table);
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if (ret)
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return ret;
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return 0;
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}
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static int cpufreq_stat_notifier_trans(struct notifier_block *nb,
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unsigned long val, void *data)
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{
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struct cpufreq_freqs *freq = data;
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struct cpufreq_stats *stat;
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int old_index, new_index;
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if (val != CPUFREQ_POSTCHANGE)
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return 0;
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stat = per_cpu(cpufreq_stats_table, freq->cpu);
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if (!stat)
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return 0;
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old_index = stat->last_index;
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new_index = freq_table_get_index(stat, freq->new);
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/* We can't do stat->time_in_state[-1]= .. */
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if (old_index == -1 || new_index == -1)
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return 0;
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cpufreq_stats_update(freq->cpu);
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if (old_index == new_index)
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return 0;
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spin_lock(&cpufreq_stats_lock);
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stat->last_index = new_index;
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#ifdef CONFIG_CPU_FREQ_STAT_DETAILS
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stat->trans_table[old_index * stat->max_state + new_index]++;
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#endif
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stat->total_trans++;
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spin_unlock(&cpufreq_stats_lock);
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return 0;
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}
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static int cpufreq_stat_cpu_callback(struct notifier_block *nfb,
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unsigned long action,
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void *hcpu)
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{
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unsigned int cpu = (unsigned long)hcpu;
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switch (action) {
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case CPU_DOWN_PREPARE:
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cpufreq_stats_free_sysfs(cpu);
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break;
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case CPU_DEAD:
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cpufreq_stats_free_table(cpu);
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break;
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}
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return NOTIFY_OK;
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}
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/* priority=1 so this will get called before cpufreq_remove_dev */
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static struct notifier_block cpufreq_stat_cpu_notifier __refdata = {
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.notifier_call = cpufreq_stat_cpu_callback,
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.priority = 1,
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};
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static struct notifier_block notifier_policy_block = {
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.notifier_call = cpufreq_stat_notifier_policy
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};
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static struct notifier_block notifier_trans_block = {
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.notifier_call = cpufreq_stat_notifier_trans
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};
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static int __init cpufreq_stats_init(void)
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{
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int ret;
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unsigned int cpu;
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spin_lock_init(&cpufreq_stats_lock);
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ret = cpufreq_register_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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if (ret)
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return ret;
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register_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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ret = cpufreq_register_notifier(¬ifier_trans_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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if (ret) {
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cpufreq_unregister_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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for_each_online_cpu(cpu)
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cpufreq_stats_free_table(cpu);
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return ret;
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}
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return 0;
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}
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static void __exit cpufreq_stats_exit(void)
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{
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unsigned int cpu;
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cpufreq_unregister_notifier(¬ifier_policy_block,
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CPUFREQ_POLICY_NOTIFIER);
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cpufreq_unregister_notifier(¬ifier_trans_block,
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CPUFREQ_TRANSITION_NOTIFIER);
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unregister_hotcpu_notifier(&cpufreq_stat_cpu_notifier);
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for_each_online_cpu(cpu) {
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cpufreq_stats_free_table(cpu);
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cpufreq_stats_free_sysfs(cpu);
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}
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}
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MODULE_AUTHOR("Zou Nan hai <nanhai.zou@intel.com>");
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MODULE_DESCRIPTION("'cpufreq_stats' - A driver to export cpufreq stats "
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"through sysfs filesystem");
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MODULE_LICENSE("GPL");
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module_init(cpufreq_stats_init);
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module_exit(cpufreq_stats_exit);
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