| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Rafael J. Wysocki | 923 | 47.04% | 39 | 47.56% |
| Viresh Kumar | 897 | 45.72% | 33 | 40.24% |
| Stratos Karafotis | 47 | 2.40% | 3 | 3.66% |
| Srivatsa S. Bhat | 45 | 2.29% | 1 | 1.22% |
| Henry Willard | 27 | 1.38% | 1 | 1.22% |
| Chen Yu | 13 | 0.66% | 1 | 1.22% |
| Bibek Basu | 3 | 0.15% | 1 | 1.22% |
| Frédéric Weisbecker | 3 | 0.15% | 1 | 1.22% |
| Rickard Andersson | 3 | 0.15% | 1 | 1.22% |
| Fabio Baltieri | 1 | 0.05% | 1 | 1.22% |
| Total | 1962 | 82 |
/* * drivers/cpufreq/cpufreq_governor.c * * CPUFREQ governors common code * * Copyright (C) 2001 Russell King * (C) 2003 Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>. * (C) 2003 Jun Nakajima <jun.nakajima@intel.com> * (C) 2009 Alexander Clouter <alex@digriz.org.uk> * (c) 2012 Viresh Kumar <viresh.kumar@linaro.org> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/export.h> #include <linux/kernel_stat.h> #include <linux/slab.h> #include "cpufreq_governor.h" #define CPUFREQ_DBS_MIN_SAMPLING_INTERVAL (2 * TICK_NSEC / NSEC_PER_USEC) static DEFINE_PER_CPU(struct cpu_dbs_info, cpu_dbs); static DEFINE_MUTEX(gov_dbs_data_mutex); /* Common sysfs tunables */ /** * store_sampling_rate - update sampling rate effective immediately if needed. * * If new rate is smaller than the old, simply updating * dbs.sampling_rate might not be appropriate. For example, if the * original sampling_rate was 1 second and the requested new sampling rate is 10 * ms because the user needs immediate reaction from ondemand governor, but not * sure if higher frequency will be required or not, then, the governor may * change the sampling rate too late; up to 1 second later. Thus, if we are * reducing the sampling rate, we need to make the new value effective * immediately. * * This must be called with dbs_data->mutex held, otherwise traversing * policy_dbs_list isn't safe. */ ssize_t store_sampling_rate(struct gov_attr_set *attr_set, const char *buf, size_t count) { struct dbs_data *dbs_data = to_dbs_data(attr_set); struct policy_dbs_info *policy_dbs; unsigned int sampling_interval; int ret; ret = sscanf(buf, "%u", &sampling_interval); if (ret != 1 || sampling_interval < CPUFREQ_DBS_MIN_SAMPLING_INTERVAL) return -EINVAL; dbs_data->sampling_rate = sampling_interval; /* * We are operating under dbs_data->mutex and so the list and its * entries can't be freed concurrently. */ list_for_each_entry(policy_dbs, &attr_set->policy_list, list) { mutex_lock(&policy_dbs->update_mutex); /* * On 32-bit architectures this may race with the * sample_delay_ns read in dbs_update_util_handler(), but that * really doesn't matter. If the read returns a value that's * too big, the sample will be skipped, but the next invocation * of dbs_update_util_handler() (when the update has been * completed) will take a sample. * * If this runs in parallel with dbs_work_handler(), we may end * up overwriting the sample_delay_ns value that it has just * written, but it will be corrected next time a sample is * taken, so it shouldn't be significant. */ gov_update_sample_delay(policy_dbs, 0); mutex_unlock(&policy_dbs->update_mutex); } return count; } EXPORT_SYMBOL_GPL(store_sampling_rate); /** * gov_update_cpu_data - Update CPU load data. * @dbs_data: Top-level governor data pointer. * * Update CPU load data for all CPUs in the domain governed by @dbs_data * (that may be a single policy or a bunch of them if governor tunables are * system-wide). * * Call under the @dbs_data mutex. */ void gov_update_cpu_data(struct dbs_data *dbs_data) { struct policy_dbs_info *policy_dbs; list_for_each_entry(policy_dbs, &dbs_data->attr_set.policy_list, list) { unsigned int j; for_each_cpu(j, policy_dbs->policy->cpus) { struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, dbs_data->io_is_busy); if (dbs_data->ignore_nice_load) j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; } } } EXPORT_SYMBOL_GPL(gov_update_cpu_data); unsigned int dbs_update(struct cpufreq_policy *policy) { struct policy_dbs_info *policy_dbs = policy->governor_data; struct dbs_data *dbs_data = policy_dbs->dbs_data; unsigned int ignore_nice = dbs_data->ignore_nice_load; unsigned int max_load = 0, idle_periods = UINT_MAX; unsigned int sampling_rate, io_busy, j; /* * Sometimes governors may use an additional multiplier to increase * sample delays temporarily. Apply that multiplier to sampling_rate * so as to keep the wake-up-from-idle detection logic a bit * conservative. */ sampling_rate = dbs_data->sampling_rate * policy_dbs->rate_mult; /* * For the purpose of ondemand, waiting for disk IO is an indication * that you're performance critical, and not that the system is actually * idle, so do not add the iowait time to the CPU idle time then. */ io_busy = dbs_data->io_is_busy; /* Get Absolute Load */ for_each_cpu(j, policy->cpus) { struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); u64 update_time, cur_idle_time; unsigned int idle_time, time_elapsed; unsigned int load; cur_idle_time = get_cpu_idle_time(j, &update_time, io_busy); time_elapsed = update_time - j_cdbs->prev_update_time; j_cdbs->prev_update_time = update_time; idle_time = cur_idle_time - j_cdbs->prev_cpu_idle; j_cdbs->prev_cpu_idle = cur_idle_time; if (ignore_nice) { u64 cur_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; idle_time += div_u64(cur_nice - j_cdbs->prev_cpu_nice, NSEC_PER_USEC); j_cdbs->prev_cpu_nice = cur_nice; } if (unlikely(!time_elapsed)) { /* * That can only happen when this function is called * twice in a row with a very short interval between the * calls, so the previous load value can be used then. */ load = j_cdbs->prev_load; } else if (unlikely((int)idle_time > 2 * sampling_rate && j_cdbs->prev_load)) { /* * If the CPU had gone completely idle and a task has * just woken up on this CPU now, it would be unfair to * calculate 'load' the usual way for this elapsed * time-window, because it would show near-zero load, * irrespective of how CPU intensive that task actually * was. This is undesirable for latency-sensitive bursty * workloads. * * To avoid this, reuse the 'load' from the previous * time-window and give this task a chance to start with * a reasonably high CPU frequency. However, that * shouldn't be over-done, lest we get stuck at a high * load (high frequency) for too long, even when the * current system load has actually dropped down, so * clear prev_load to guarantee that the load will be * computed again next time. * * Detecting this situation is easy: an unusually large * 'idle_time' (as compared to the sampling rate) * indicates this scenario. */ load = j_cdbs->prev_load; j_cdbs->prev_load = 0; } else { if (time_elapsed >= idle_time) { load = 100 * (time_elapsed - idle_time) / time_elapsed; } else { /* * That can happen if idle_time is returned by * get_cpu_idle_time_jiffy(). In that case * idle_time is roughly equal to the difference * between time_elapsed and "busy time" obtained * from CPU statistics. Then, the "busy time" * can end up being greater than time_elapsed * (for example, if jiffies_64 and the CPU * statistics are updated by different CPUs), * so idle_time may in fact be negative. That * means, though, that the CPU was busy all * the time (on the rough average) during the * last sampling interval and 100 can be * returned as the load. */ load = (int)idle_time < 0 ? 100 : 0; } j_cdbs->prev_load = load; } if (unlikely((int)idle_time > 2 * sampling_rate)) { unsigned int periods = idle_time / sampling_rate; if (periods < idle_periods) idle_periods = periods; } if (load > max_load) max_load = load; } policy_dbs->idle_periods = idle_periods; return max_load; } EXPORT_SYMBOL_GPL(dbs_update); static void dbs_work_handler(struct work_struct *work) { struct policy_dbs_info *policy_dbs; struct cpufreq_policy *policy; struct dbs_governor *gov; policy_dbs = container_of(work, struct policy_dbs_info, work); policy = policy_dbs->policy; gov = dbs_governor_of(policy); /* * Make sure cpufreq_governor_limits() isn't evaluating load or the * ondemand governor isn't updating the sampling rate in parallel. */ mutex_lock(&policy_dbs->update_mutex); gov_update_sample_delay(policy_dbs, gov->gov_dbs_update(policy)); mutex_unlock(&policy_dbs->update_mutex); /* Allow the utilization update handler to queue up more work. */ atomic_set(&policy_dbs->work_count, 0); /* * If the update below is reordered with respect to the sample delay * modification, the utilization update handler may end up using a stale * sample delay value. */ smp_wmb(); policy_dbs->work_in_progress = false; } static void dbs_irq_work(struct irq_work *irq_work) { struct policy_dbs_info *policy_dbs; policy_dbs = container_of(irq_work, struct policy_dbs_info, irq_work); schedule_work_on(smp_processor_id(), &policy_dbs->work); } static void dbs_update_util_handler(struct update_util_data *data, u64 time, unsigned int flags) { struct cpu_dbs_info *cdbs = container_of(data, struct cpu_dbs_info, update_util); struct policy_dbs_info *policy_dbs = cdbs->policy_dbs; u64 delta_ns, lst; if (!cpufreq_this_cpu_can_update(policy_dbs->policy)) return; /* * The work may not be allowed to be queued up right now. * Possible reasons: * - Work has already been queued up or is in progress. * - It is too early (too little time from the previous sample). */ if (policy_dbs->work_in_progress) return; /* * If the reads below are reordered before the check above, the value * of sample_delay_ns used in the computation may be stale. */ smp_rmb(); lst = READ_ONCE(policy_dbs->last_sample_time); delta_ns = time - lst; if ((s64)delta_ns < policy_dbs->sample_delay_ns) return; /* * If the policy is not shared, the irq_work may be queued up right away * at this point. Otherwise, we need to ensure that only one of the * CPUs sharing the policy will do that. */ if (policy_dbs->is_shared) { if (!atomic_add_unless(&policy_dbs->work_count, 1, 1)) return; /* * If another CPU updated last_sample_time in the meantime, we * shouldn't be here, so clear the work counter and bail out. */ if (unlikely(lst != READ_ONCE(policy_dbs->last_sample_time))) { atomic_set(&policy_dbs->work_count, 0); return; } } policy_dbs->last_sample_time = time; policy_dbs->work_in_progress = true; irq_work_queue(&policy_dbs->irq_work); } static void gov_set_update_util(struct policy_dbs_info *policy_dbs, unsigned int delay_us) { struct cpufreq_policy *policy = policy_dbs->policy; int cpu; gov_update_sample_delay(policy_dbs, delay_us); policy_dbs->last_sample_time = 0; for_each_cpu(cpu, policy->cpus) { struct cpu_dbs_info *cdbs = &per_cpu(cpu_dbs, cpu); cpufreq_add_update_util_hook(cpu, &cdbs->update_util, dbs_update_util_handler); } } static inline void gov_clear_update_util(struct cpufreq_policy *policy) { int i; for_each_cpu(i, policy->cpus) cpufreq_remove_update_util_hook(i); synchronize_sched(); } static struct policy_dbs_info *alloc_policy_dbs_info(struct cpufreq_policy *policy, struct dbs_governor *gov) { struct policy_dbs_info *policy_dbs; int j; /* Allocate memory for per-policy governor data. */ policy_dbs = gov->alloc(); if (!policy_dbs) return NULL; policy_dbs->policy = policy; mutex_init(&policy_dbs->update_mutex); atomic_set(&policy_dbs->work_count, 0); init_irq_work(&policy_dbs->irq_work, dbs_irq_work); INIT_WORK(&policy_dbs->work, dbs_work_handler); /* Set policy_dbs for all CPUs, online+offline */ for_each_cpu(j, policy->related_cpus) { struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); j_cdbs->policy_dbs = policy_dbs; } return policy_dbs; } static void free_policy_dbs_info(struct policy_dbs_info *policy_dbs, struct dbs_governor *gov) { int j; mutex_destroy(&policy_dbs->update_mutex); for_each_cpu(j, policy_dbs->policy->related_cpus) { struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); j_cdbs->policy_dbs = NULL; j_cdbs->update_util.func = NULL; } gov->free(policy_dbs); } int cpufreq_dbs_governor_init(struct cpufreq_policy *policy) { struct dbs_governor *gov = dbs_governor_of(policy); struct dbs_data *dbs_data; struct policy_dbs_info *policy_dbs; int ret = 0; /* State should be equivalent to EXIT */ if (policy->governor_data) return -EBUSY; policy_dbs = alloc_policy_dbs_info(policy, gov); if (!policy_dbs) return -ENOMEM; /* Protect gov->gdbs_data against concurrent updates. */ mutex_lock(&gov_dbs_data_mutex); dbs_data = gov->gdbs_data; if (dbs_data) { if (WARN_ON(have_governor_per_policy())) { ret = -EINVAL; goto free_policy_dbs_info; } policy_dbs->dbs_data = dbs_data; policy->governor_data = policy_dbs; gov_attr_set_get(&dbs_data->attr_set, &policy_dbs->list); goto out; } dbs_data = kzalloc(sizeof(*dbs_data), GFP_KERNEL); if (!dbs_data) { ret = -ENOMEM; goto free_policy_dbs_info; } gov_attr_set_init(&dbs_data->attr_set, &policy_dbs->list); ret = gov->init(dbs_data); if (ret) goto free_policy_dbs_info; /* * The sampling interval should not be less than the transition latency * of the CPU and it also cannot be too small for dbs_update() to work * correctly. */ dbs_data->sampling_rate = max_t(unsigned int, CPUFREQ_DBS_MIN_SAMPLING_INTERVAL, cpufreq_policy_transition_delay_us(policy)); if (!have_governor_per_policy()) gov->gdbs_data = dbs_data; policy_dbs->dbs_data = dbs_data; policy->governor_data = policy_dbs; gov->kobj_type.sysfs_ops = &governor_sysfs_ops; ret = kobject_init_and_add(&dbs_data->attr_set.kobj, &gov->kobj_type, get_governor_parent_kobj(policy), "%s", gov->gov.name); if (!ret) goto out; /* Failure, so roll back. */ pr_err("initialization failed (dbs_data kobject init error %d)\n", ret); policy->governor_data = NULL; if (!have_governor_per_policy()) gov->gdbs_data = NULL; gov->exit(dbs_data); kfree(dbs_data); free_policy_dbs_info: free_policy_dbs_info(policy_dbs, gov); out: mutex_unlock(&gov_dbs_data_mutex); return ret; } EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_init); void cpufreq_dbs_governor_exit(struct cpufreq_policy *policy) { struct dbs_governor *gov = dbs_governor_of(policy); struct policy_dbs_info *policy_dbs = policy->governor_data; struct dbs_data *dbs_data = policy_dbs->dbs_data; unsigned int count; /* Protect gov->gdbs_data against concurrent updates. */ mutex_lock(&gov_dbs_data_mutex); count = gov_attr_set_put(&dbs_data->attr_set, &policy_dbs->list); policy->governor_data = NULL; if (!count) { if (!have_governor_per_policy()) gov->gdbs_data = NULL; gov->exit(dbs_data); kfree(dbs_data); } free_policy_dbs_info(policy_dbs, gov); mutex_unlock(&gov_dbs_data_mutex); } EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_exit); int cpufreq_dbs_governor_start(struct cpufreq_policy *policy) { struct dbs_governor *gov = dbs_governor_of(policy); struct policy_dbs_info *policy_dbs = policy->governor_data; struct dbs_data *dbs_data = policy_dbs->dbs_data; unsigned int sampling_rate, ignore_nice, j; unsigned int io_busy; if (!policy->cur) return -EINVAL; policy_dbs->is_shared = policy_is_shared(policy); policy_dbs->rate_mult = 1; sampling_rate = dbs_data->sampling_rate; ignore_nice = dbs_data->ignore_nice_load; io_busy = dbs_data->io_is_busy; for_each_cpu(j, policy->cpus) { struct cpu_dbs_info *j_cdbs = &per_cpu(cpu_dbs, j); j_cdbs->prev_cpu_idle = get_cpu_idle_time(j, &j_cdbs->prev_update_time, io_busy); /* * Make the first invocation of dbs_update() compute the load. */ j_cdbs->prev_load = 0; if (ignore_nice) j_cdbs->prev_cpu_nice = kcpustat_cpu(j).cpustat[CPUTIME_NICE]; } gov->start(policy); gov_set_update_util(policy_dbs, sampling_rate); return 0; } EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_start); void cpufreq_dbs_governor_stop(struct cpufreq_policy *policy) { struct policy_dbs_info *policy_dbs = policy->governor_data; gov_clear_update_util(policy_dbs->policy); irq_work_sync(&policy_dbs->irq_work); cancel_work_sync(&policy_dbs->work); atomic_set(&policy_dbs->work_count, 0); policy_dbs->work_in_progress = false; } EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_stop); void cpufreq_dbs_governor_limits(struct cpufreq_policy *policy) { struct policy_dbs_info *policy_dbs; /* Protect gov->gdbs_data against cpufreq_dbs_governor_exit() */ mutex_lock(&gov_dbs_data_mutex); policy_dbs = policy->governor_data; if (!policy_dbs) goto out; mutex_lock(&policy_dbs->update_mutex); cpufreq_policy_apply_limits(policy); gov_update_sample_delay(policy_dbs, 0); mutex_unlock(&policy_dbs->update_mutex); out: mutex_unlock(&gov_dbs_data_mutex); } EXPORT_SYMBOL_GPL(cpufreq_dbs_governor_limits);
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