cpufreq_gov_performance_init
    cpufreq_register_governor(&cpufreq_gov_performance);
        list_add(&governor->governor_list, &cpufreq_governor_list);	

cpufreq_gov_performance_limits
    __cpufreq_driver_target(policy, policy->max, CPUFREQ_RELATION_H);	// policy->max在cpufreq_driver->init中进行设置
        // 找到cpufreq_frequency_table中最接近target的index
        index = cpufreq_frequency_table_target(policy, target_freq, relation);
            return cpufreq_table_find_index_h(policy, target_freq);
                // 根据cpufreq_frequency_table选择，例如s5pv210-cpufreq.c中该表为降序排列
                return cpufreq_table_find_index_dh(policy, target_freq);
        // call cpufreq_drvier->target_index
        __target_index(policy, index);
            cpufreq_driver->target_index(policy, index);

static struct  cpufreq_gov_performance = {
    .limits		= cpufreq_gov_performance_limits,
};