| /* Copyright (c) 2014-2016, The Linux Foundation. All rights reserved. |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 and |
| * only version 2 as published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/notifier.h> |
| #include <linux/cpu.h> |
| #include <linux/cpumask.h> |
| #include <linux/cpufreq.h> |
| #include <linux/timer.h> |
| #include <linux/kthread.h> |
| #include <linux/sched.h> |
| #include <linux/sched/rt.h> |
| #include <linux/mutex.h> |
| |
| #include <trace/events/sched.h> |
| |
| #define MAX_CPUS_PER_GROUP 4 |
| |
| struct cpu_data { |
| /* Per CPU data. */ |
| bool inited; |
| bool online; |
| bool rejected; |
| bool is_busy; |
| bool not_preferred; |
| unsigned int busy; |
| unsigned int cpu; |
| struct list_head sib; |
| unsigned int first_cpu; |
| struct list_head pending_sib; |
| |
| /* Per cluster data set only on first CPU */ |
| unsigned int min_cpus; |
| unsigned int max_cpus; |
| unsigned int offline_delay_ms; |
| unsigned int busy_up_thres[MAX_CPUS_PER_GROUP]; |
| unsigned int busy_down_thres[MAX_CPUS_PER_GROUP]; |
| unsigned int online_cpus; |
| unsigned int avail_cpus; |
| unsigned int num_cpus; |
| unsigned int need_cpus; |
| unsigned int task_thres; |
| s64 need_ts; |
| struct list_head lru; |
| bool pending; |
| spinlock_t pending_lock; |
| bool is_big_cluster; |
| int nrrun; |
| bool nrrun_changed; |
| struct timer_list timer; |
| struct task_struct *hotplug_thread; |
| struct kobject kobj; |
| struct list_head pending_lru; |
| bool disabled; |
| }; |
| |
| static DEFINE_PER_CPU(struct cpu_data, cpu_state); |
| static DEFINE_SPINLOCK(state_lock); |
| static DEFINE_SPINLOCK(pending_lru_lock); |
| static DEFINE_MUTEX(lru_lock); |
| |
| static void apply_need(struct cpu_data *f); |
| static void wake_up_hotplug_thread(struct cpu_data *state); |
| static void add_to_pending_lru(struct cpu_data *state); |
| static void update_lru(struct cpu_data *state); |
| |
| /* ========================= sysfs interface =========================== */ |
| |
| static ssize_t store_min_cpus(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| state->min_cpus = min(val, state->max_cpus); |
| wake_up_hotplug_thread(state); |
| |
| return count; |
| } |
| |
| static ssize_t show_min_cpus(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->min_cpus); |
| } |
| |
| static ssize_t store_max_cpus(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| val = min(val, state->num_cpus); |
| state->max_cpus = val; |
| state->min_cpus = min(state->min_cpus, state->max_cpus); |
| wake_up_hotplug_thread(state); |
| |
| return count; |
| } |
| |
| static ssize_t show_max_cpus(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->max_cpus); |
| } |
| |
| static ssize_t store_offline_delay_ms(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| state->offline_delay_ms = val; |
| apply_need(state); |
| |
| return count; |
| } |
| |
| static ssize_t show_task_thres(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->task_thres); |
| } |
| |
| static ssize_t store_task_thres(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| if (val < state->num_cpus) |
| return -EINVAL; |
| |
| state->task_thres = val; |
| apply_need(state); |
| |
| return count; |
| } |
| |
| static ssize_t show_offline_delay_ms(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->offline_delay_ms); |
| } |
| |
| static ssize_t store_busy_up_thres(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val[MAX_CPUS_PER_GROUP]; |
| int ret, i; |
| |
| ret = sscanf(buf, "%u %u %u %u\n", &val[0], &val[1], &val[2], &val[3]); |
| if (ret != 1 && ret != state->num_cpus) |
| return -EINVAL; |
| |
| if (ret == 1) { |
| for (i = 0; i < state->num_cpus; i++) |
| state->busy_up_thres[i] = val[0]; |
| } else { |
| for (i = 0; i < state->num_cpus; i++) |
| state->busy_up_thres[i] = val[i]; |
| } |
| apply_need(state); |
| return count; |
| } |
| |
| static ssize_t show_busy_up_thres(struct cpu_data *state, char *buf) |
| { |
| int i, count = 0; |
| |
| for (i = 0; i < state->num_cpus; i++) |
| count += snprintf(buf + count, PAGE_SIZE - count, "%u ", |
| state->busy_up_thres[i]); |
| count += snprintf(buf + count, PAGE_SIZE - count, "\n"); |
| return count; |
| } |
| |
| static ssize_t store_busy_down_thres(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val[MAX_CPUS_PER_GROUP]; |
| int ret, i; |
| |
| ret = sscanf(buf, "%u %u %u %u\n", &val[0], &val[1], &val[2], &val[3]); |
| if (ret != 1 && ret != state->num_cpus) |
| return -EINVAL; |
| |
| if (ret == 1) { |
| for (i = 0; i < state->num_cpus; i++) |
| state->busy_down_thres[i] = val[0]; |
| } else { |
| for (i = 0; i < state->num_cpus; i++) |
| state->busy_down_thres[i] = val[i]; |
| } |
| apply_need(state); |
| return count; |
| } |
| |
| static ssize_t show_busy_down_thres(struct cpu_data *state, char *buf) |
| { |
| int i, count = 0; |
| |
| for (i = 0; i < state->num_cpus; i++) |
| count += snprintf(buf + count, PAGE_SIZE - count, "%u ", |
| state->busy_down_thres[i]); |
| count += snprintf(buf + count, PAGE_SIZE - count, "\n"); |
| return count; |
| } |
| |
| static ssize_t store_is_big_cluster(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| state->is_big_cluster = val ? 1 : 0; |
| return count; |
| } |
| |
| static ssize_t show_is_big_cluster(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->is_big_cluster); |
| } |
| |
| static ssize_t show_cpus(struct cpu_data *state, char *buf) |
| { |
| struct cpu_data *c; |
| ssize_t count = 0; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&state_lock, flags); |
| list_for_each_entry(c, &state->lru, sib) { |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "CPU%u (%s)\n", c->cpu, |
| c->online ? "Online" : "Offline"); |
| } |
| spin_unlock_irqrestore(&state_lock, flags); |
| return count; |
| } |
| |
| static ssize_t show_need_cpus(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->need_cpus); |
| } |
| |
| static ssize_t show_online_cpus(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->online_cpus); |
| } |
| |
| static ssize_t show_global_state(struct cpu_data *state, char *buf) |
| { |
| struct cpu_data *c; |
| ssize_t count = 0; |
| unsigned int cpu; |
| |
| for_each_possible_cpu(cpu) { |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "CPU%u\n", cpu); |
| c = &per_cpu(cpu_state, cpu); |
| if (!c->inited) |
| continue; |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tCPU: %u\n", c->cpu); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tOnline: %u\n", c->online); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tRejected: %u\n", c->rejected); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tFirst CPU: %u\n", c->first_cpu); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tBusy%%: %u\n", c->busy); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tIs busy: %u\n", c->is_busy); |
| if (c->cpu != c->first_cpu) |
| continue; |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tNr running: %u\n", c->nrrun); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tAvail CPUs: %u\n", c->avail_cpus); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tNeed CPUs: %u\n", c->need_cpus); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tStatus: %s\n", |
| c->disabled ? "disabled" : "enabled"); |
| } |
| |
| return count; |
| } |
| |
| static ssize_t store_not_preferred(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| struct cpu_data *c; |
| unsigned int i, first_cpu; |
| unsigned int val[MAX_CPUS_PER_GROUP]; |
| int ret; |
| |
| ret = sscanf(buf, "%u %u %u %u\n", &val[0], &val[1], &val[2], &val[3]); |
| if (ret != 1 && ret != state->num_cpus) |
| return -EINVAL; |
| |
| first_cpu = state->first_cpu; |
| |
| for (i = 0; i < state->num_cpus; i++) { |
| c = &per_cpu(cpu_state, first_cpu); |
| c->not_preferred = val[i]; |
| first_cpu++; |
| } |
| |
| return count; |
| } |
| |
| static ssize_t show_not_preferred(struct cpu_data *state, char *buf) |
| { |
| struct cpu_data *c; |
| ssize_t count = 0; |
| unsigned int i, first_cpu; |
| |
| first_cpu = state->first_cpu; |
| |
| for (i = 0; i < state->num_cpus; i++) { |
| c = &per_cpu(cpu_state, first_cpu); |
| count += snprintf(buf + count, PAGE_SIZE - count, |
| "\tCPU:%d %u\n", first_cpu, c->not_preferred); |
| first_cpu++; |
| } |
| |
| return count; |
| } |
| |
| static ssize_t store_disable(struct cpu_data *state, |
| const char *buf, size_t count) |
| { |
| unsigned int val; |
| |
| if (sscanf(buf, "%u\n", &val) != 1) |
| return -EINVAL; |
| |
| val = !!val; |
| |
| if (state->disabled == val) |
| return count; |
| |
| state->disabled = val; |
| |
| if (!state->disabled) |
| wake_up_hotplug_thread(state); |
| |
| |
| return count; |
| } |
| |
| static ssize_t show_disable(struct cpu_data *state, char *buf) |
| { |
| return snprintf(buf, PAGE_SIZE, "%u\n", state->disabled); |
| } |
| |
| struct core_ctl_attr { |
| struct attribute attr; |
| ssize_t (*show)(struct cpu_data *, char *); |
| ssize_t (*store)(struct cpu_data *, const char *, size_t count); |
| }; |
| |
| #define core_ctl_attr_ro(_name) \ |
| static struct core_ctl_attr _name = \ |
| __ATTR(_name, 0444, show_##_name, NULL) |
| |
| #define core_ctl_attr_rw(_name) \ |
| static struct core_ctl_attr _name = \ |
| __ATTR(_name, 0644, show_##_name, store_##_name) |
| |
| core_ctl_attr_rw(min_cpus); |
| core_ctl_attr_rw(max_cpus); |
| core_ctl_attr_rw(offline_delay_ms); |
| core_ctl_attr_rw(busy_up_thres); |
| core_ctl_attr_rw(busy_down_thres); |
| core_ctl_attr_rw(task_thres); |
| core_ctl_attr_rw(is_big_cluster); |
| core_ctl_attr_ro(cpus); |
| core_ctl_attr_ro(need_cpus); |
| core_ctl_attr_ro(online_cpus); |
| core_ctl_attr_ro(global_state); |
| core_ctl_attr_rw(not_preferred); |
| core_ctl_attr_rw(disable); |
| |
| static struct attribute *default_attrs[] = { |
| &min_cpus.attr, |
| &max_cpus.attr, |
| &offline_delay_ms.attr, |
| &busy_up_thres.attr, |
| &busy_down_thres.attr, |
| &task_thres.attr, |
| &is_big_cluster.attr, |
| &cpus.attr, |
| &need_cpus.attr, |
| &online_cpus.attr, |
| &global_state.attr, |
| ¬_preferred.attr, |
| &disable.attr, |
| NULL |
| }; |
| |
| #define to_cpu_data(k) container_of(k, struct cpu_data, kobj) |
| #define to_attr(a) container_of(a, struct core_ctl_attr, attr) |
| static ssize_t show(struct kobject *kobj, struct attribute *attr, char *buf) |
| { |
| struct cpu_data *data = to_cpu_data(kobj); |
| struct core_ctl_attr *cattr = to_attr(attr); |
| ssize_t ret = -EIO; |
| |
| if (cattr->show) |
| ret = cattr->show(data, buf); |
| |
| return ret; |
| } |
| |
| static ssize_t store(struct kobject *kobj, struct attribute *attr, |
| const char *buf, size_t count) |
| { |
| struct cpu_data *data = to_cpu_data(kobj); |
| struct core_ctl_attr *cattr = to_attr(attr); |
| ssize_t ret = -EIO; |
| |
| if (cattr->store) |
| ret = cattr->store(data, buf, count); |
| |
| return ret; |
| } |
| |
| static const struct sysfs_ops sysfs_ops = { |
| .show = show, |
| .store = store, |
| }; |
| |
| static struct kobj_type ktype_core_ctl = { |
| .sysfs_ops = &sysfs_ops, |
| .default_attrs = default_attrs, |
| }; |
| |
| /* ==================== runqueue based core count =================== */ |
| |
| #define RQ_AVG_TOLERANCE 2 |
| #define RQ_AVG_DEFAULT_MS 20 |
| #define NR_RUNNING_TOLERANCE 5 |
| static unsigned int rq_avg_period_ms = RQ_AVG_DEFAULT_MS; |
| |
| static s64 rq_avg_timestamp_ms; |
| static struct timer_list rq_avg_timer; |
| |
| static void update_running_avg(bool trigger_update) |
| { |
| int cpu; |
| struct cpu_data *pcpu; |
| int avg, iowait_avg, big_avg, old_nrrun; |
| s64 now; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&state_lock, flags); |
| |
| now = ktime_to_ms(ktime_get()); |
| if (now - rq_avg_timestamp_ms < rq_avg_period_ms - RQ_AVG_TOLERANCE) { |
| spin_unlock_irqrestore(&state_lock, flags); |
| return; |
| } |
| rq_avg_timestamp_ms = now; |
| sched_get_nr_running_avg(&avg, &iowait_avg, &big_avg); |
| |
| spin_unlock_irqrestore(&state_lock, flags); |
| |
| /* |
| * Round up to the next integer if the average nr running tasks |
| * is within NR_RUNNING_TOLERANCE/100 of the next integer. |
| * If normal rounding up is used, it will allow a transient task |
| * to trigger online event. By the time core is onlined, the task |
| * has finished. |
| * Rounding to closest suffers same problem because scheduler |
| * might only provide running stats per jiffy, and a transient |
| * task could skew the number for one jiffy. If core control |
| * samples every 2 jiffies, it will observe 0.5 additional running |
| * average which rounds up to 1 task. |
| */ |
| avg = (avg + NR_RUNNING_TOLERANCE) / 100; |
| big_avg = (big_avg + NR_RUNNING_TOLERANCE) / 100; |
| |
| for_each_possible_cpu(cpu) { |
| pcpu = &per_cpu(cpu_state, cpu); |
| if (!pcpu->inited || pcpu->first_cpu != cpu) |
| continue; |
| old_nrrun = pcpu->nrrun; |
| /* |
| * Big cluster only need to take care of big tasks, but if |
| * there are not enough big cores, big tasks need to be run |
| * on little as well. Thus for little's runqueue stat, it |
| * has to use overall runqueue average, or derive what big |
| * tasks would have to be run on little. The latter approach |
| * is not easy to get given core control reacts much slower |
| * than scheduler, and can't predict scheduler's behavior. |
| */ |
| pcpu->nrrun = pcpu->is_big_cluster ? big_avg : avg; |
| if (pcpu->nrrun != old_nrrun) { |
| if (trigger_update) |
| apply_need(pcpu); |
| else |
| pcpu->nrrun_changed = true; |
| } |
| } |
| } |
| |
| /* adjust needed CPUs based on current runqueue information */ |
| static unsigned int apply_task_need(struct cpu_data *f, unsigned int new_need) |
| { |
| /* Online all cores if there are enough tasks */ |
| if (f->nrrun >= f->task_thres) |
| return f->num_cpus; |
| |
| /* only online more cores if there are tasks to run */ |
| if (f->nrrun > new_need) |
| return new_need + 1; |
| |
| return new_need; |
| } |
| |
| static u64 round_to_nw_start(void) |
| { |
| unsigned long step = msecs_to_jiffies(rq_avg_period_ms); |
| u64 jif = get_jiffies_64(); |
| |
| do_div(jif, step); |
| return (jif + 1) * step; |
| } |
| |
| static void rq_avg_timer_func(unsigned long not_used) |
| { |
| update_running_avg(true); |
| mod_timer(&rq_avg_timer, round_to_nw_start()); |
| } |
| |
| /* ======================= load based core count ====================== */ |
| |
| static unsigned int apply_limits(struct cpu_data *f, unsigned int need_cpus) |
| { |
| return min(max(f->min_cpus, need_cpus), f->max_cpus); |
| } |
| |
| static bool eval_need(struct cpu_data *f) |
| { |
| unsigned long flags; |
| struct cpu_data *c; |
| unsigned int need_cpus = 0, last_need, thres_idx; |
| int ret = 0; |
| bool need_flag = false; |
| s64 now; |
| |
| if (unlikely(!f->inited)) |
| return 0; |
| |
| spin_lock_irqsave(&state_lock, flags); |
| thres_idx = f->online_cpus ? f->online_cpus - 1 : 0; |
| list_for_each_entry(c, &f->lru, sib) { |
| if (c->busy >= f->busy_up_thres[thres_idx]) |
| c->is_busy = true; |
| else if (c->busy < f->busy_down_thres[thres_idx]) |
| c->is_busy = false; |
| need_cpus += c->is_busy; |
| } |
| need_cpus = apply_task_need(f, need_cpus); |
| need_flag = apply_limits(f, need_cpus) != apply_limits(f, f->need_cpus); |
| last_need = f->need_cpus; |
| |
| now = ktime_to_ms(ktime_get()); |
| |
| if (need_cpus == last_need) { |
| f->need_ts = now; |
| spin_unlock_irqrestore(&state_lock, flags); |
| return 0; |
| } |
| |
| if (need_cpus > last_need) { |
| ret = 1; |
| } else if (need_cpus < last_need) { |
| s64 elapsed = now - f->need_ts; |
| |
| if (elapsed >= f->offline_delay_ms) { |
| ret = 1; |
| } else { |
| mod_timer(&f->timer, jiffies + |
| msecs_to_jiffies(f->offline_delay_ms)); |
| } |
| } |
| |
| if (ret) { |
| f->need_ts = now; |
| f->need_cpus = need_cpus; |
| } |
| |
| trace_core_ctl_eval_need(f->cpu, last_need, need_cpus, |
| ret && need_flag); |
| spin_unlock_irqrestore(&state_lock, flags); |
| |
| return ret && need_flag; |
| } |
| |
| static void apply_need(struct cpu_data *f) |
| { |
| if (eval_need(f)) |
| wake_up_hotplug_thread(f); |
| } |
| |
| static int core_ctl_set_busy(unsigned int cpu, unsigned int busy) |
| { |
| struct cpu_data *c = &per_cpu(cpu_state, cpu); |
| struct cpu_data *f; |
| unsigned int old_is_busy = c->is_busy; |
| |
| if (!c->inited) |
| return 0; |
| f = &per_cpu(cpu_state, c->first_cpu); |
| |
| update_running_avg(false); |
| if (c->busy == busy && !f->nrrun_changed) |
| return 0; |
| c->busy = busy; |
| f->nrrun_changed = false; |
| |
| apply_need(f); |
| trace_core_ctl_set_busy(cpu, busy, old_is_busy, c->is_busy); |
| return 0; |
| } |
| |
| /* ========================= core count enforcement ==================== */ |
| |
| /* |
| * If current thread is hotplug thread, don't attempt to wake up |
| * itself or other hotplug threads because it will deadlock. Instead, |
| * schedule a timer to fire in next timer tick and wake up the thread. |
| */ |
| static void wake_up_hotplug_thread(struct cpu_data *state) |
| { |
| unsigned long flags; |
| int cpu; |
| struct cpu_data *pcpu; |
| bool no_wakeup = false; |
| |
| if (unlikely(state->disabled)) |
| return; |
| |
| for_each_possible_cpu(cpu) { |
| pcpu = &per_cpu(cpu_state, cpu); |
| if (cpu != pcpu->first_cpu) |
| continue; |
| if (pcpu->hotplug_thread == current) { |
| no_wakeup = true; |
| break; |
| } |
| } |
| |
| spin_lock_irqsave(&state->pending_lock, flags); |
| state->pending = true; |
| spin_unlock_irqrestore(&state->pending_lock, flags); |
| |
| if (no_wakeup) { |
| spin_lock_irqsave(&state_lock, flags); |
| mod_timer(&state->timer, jiffies); |
| spin_unlock_irqrestore(&state_lock, flags); |
| } else { |
| wake_up_process(state->hotplug_thread); |
| } |
| } |
| |
| static void core_ctl_timer_func(unsigned long cpu) |
| { |
| struct cpu_data *state = &per_cpu(cpu_state, cpu); |
| unsigned long flags; |
| |
| if (eval_need(state) && !state->disabled) { |
| spin_lock_irqsave(&state->pending_lock, flags); |
| state->pending = true; |
| spin_unlock_irqrestore(&state->pending_lock, flags); |
| wake_up_process(state->hotplug_thread); |
| } |
| |
| } |
| |
| static int core_ctl_online_core(unsigned int cpu) |
| { |
| int ret; |
| struct device *dev; |
| |
| lock_device_hotplug(); |
| dev = get_cpu_device(cpu); |
| if (!dev) { |
| pr_err("%s: failed to get cpu%d device\n", __func__, cpu); |
| ret = -ENODEV; |
| } else { |
| ret = device_online(dev); |
| } |
| unlock_device_hotplug(); |
| return ret; |
| } |
| |
| static int core_ctl_offline_core(unsigned int cpu) |
| { |
| int ret; |
| struct device *dev; |
| |
| lock_device_hotplug(); |
| dev = get_cpu_device(cpu); |
| if (!dev) { |
| pr_err("%s: failed to get cpu%d device\n", __func__, cpu); |
| ret = -ENODEV; |
| } else { |
| ret = device_offline(dev); |
| } |
| unlock_device_hotplug(); |
| return ret; |
| } |
| |
| static void update_lru(struct cpu_data *f) |
| { |
| struct cpu_data *c, *tmp; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&pending_lru_lock, flags); |
| spin_lock(&state_lock); |
| |
| list_for_each_entry_safe(c, tmp, &f->pending_lru, pending_sib) { |
| list_del_init(&c->pending_sib); |
| list_del(&c->sib); |
| list_add_tail(&c->sib, &f->lru); |
| } |
| |
| spin_unlock(&state_lock); |
| spin_unlock_irqrestore(&pending_lru_lock, flags); |
| } |
| |
| static void __ref do_hotplug(struct cpu_data *f) |
| { |
| unsigned int need; |
| struct cpu_data *c, *tmp; |
| |
| need = apply_limits(f, f->need_cpus); |
| pr_debug("Trying to adjust group %u to %u\n", f->first_cpu, need); |
| |
| mutex_lock(&lru_lock); |
| if (f->online_cpus > need) { |
| list_for_each_entry_safe_reverse(c, tmp, &f->lru, sib) { |
| if (!c->online) |
| continue; |
| |
| if (f->online_cpus == need) |
| break; |
| |
| /* Don't offline busy CPUs. */ |
| if (c->is_busy) |
| continue; |
| |
| pr_debug("Trying to Offline CPU%u\n", c->cpu); |
| if (core_ctl_offline_core(c->cpu)) |
| pr_debug("Unable to Offline CPU%u\n", c->cpu); |
| } |
| |
| /* |
| * If the number of online CPUs is within the limits, then |
| * don't force any busy CPUs offline. |
| */ |
| if (f->online_cpus <= f->max_cpus) |
| goto done; |
| |
| list_for_each_entry_safe_reverse(c, tmp, &f->lru, sib) { |
| if (!c->online) |
| continue; |
| |
| if (f->online_cpus <= f->max_cpus) |
| break; |
| |
| pr_debug("Trying to Offline CPU%u\n", c->cpu); |
| if (core_ctl_offline_core(c->cpu)) |
| pr_debug("Unable to Offline CPU%u\n", c->cpu); |
| } |
| } else if (f->online_cpus < need) { |
| list_for_each_entry_safe(c, tmp, &f->lru, sib) { |
| if (c->online || c->rejected || c->not_preferred) |
| continue; |
| if (f->online_cpus == need) |
| break; |
| |
| pr_debug("Trying to Online CPU%u\n", c->cpu); |
| if (core_ctl_online_core(c->cpu)) |
| pr_debug("Unable to Online CPU%u\n", c->cpu); |
| } |
| |
| if (f->online_cpus == need) |
| goto done; |
| |
| |
| list_for_each_entry_safe(c, tmp, &f->lru, sib) { |
| if (c->online || c->rejected || !c->not_preferred) |
| continue; |
| if (f->online_cpus == need) |
| break; |
| |
| pr_debug("Trying to Online CPU%u\n", c->cpu); |
| if (core_ctl_online_core(c->cpu)) |
| pr_debug("Unable to Online CPU%u\n", c->cpu); |
| } |
| } |
| done: |
| mutex_unlock(&lru_lock); |
| update_lru(f); |
| } |
| |
| static int __ref try_hotplug(void *data) |
| { |
| struct cpu_data *f = data; |
| unsigned long flags; |
| |
| while (1) { |
| set_current_state(TASK_INTERRUPTIBLE); |
| spin_lock_irqsave(&f->pending_lock, flags); |
| if (!f->pending) { |
| spin_unlock_irqrestore(&f->pending_lock, flags); |
| schedule(); |
| if (kthread_should_stop()) |
| break; |
| spin_lock_irqsave(&f->pending_lock, flags); |
| } |
| set_current_state(TASK_RUNNING); |
| f->pending = false; |
| spin_unlock_irqrestore(&f->pending_lock, flags); |
| |
| do_hotplug(f); |
| } |
| |
| return 0; |
| } |
| |
| static void add_to_pending_lru(struct cpu_data *state) |
| { |
| unsigned long flags; |
| struct cpu_data *f = &per_cpu(cpu_state, state->first_cpu); |
| |
| spin_lock_irqsave(&pending_lru_lock, flags); |
| |
| if (!list_empty(&state->pending_sib)) |
| list_del(&state->pending_sib); |
| list_add_tail(&state->pending_sib, &f->pending_lru); |
| |
| spin_unlock_irqrestore(&pending_lru_lock, flags); |
| } |
| |
| static int __ref cpu_callback(struct notifier_block *nfb, |
| unsigned long action, void *hcpu) |
| { |
| uint32_t cpu = (uintptr_t)hcpu; |
| struct cpu_data *state = &per_cpu(cpu_state, cpu); |
| struct cpu_data *f; |
| int ret = NOTIFY_OK; |
| unsigned long flags; |
| |
| /* Don't affect suspend resume */ |
| if (action & CPU_TASKS_FROZEN) |
| return NOTIFY_OK; |
| |
| if (unlikely(!state->inited)) |
| return NOTIFY_OK; |
| |
| f = &per_cpu(cpu_state, state->first_cpu); |
| |
| switch (action) { |
| case CPU_UP_PREPARE: |
| |
| /* If online state of CPU somehow got out of sync, fix it. */ |
| if (state->online) { |
| f->online_cpus--; |
| state->online = false; |
| pr_warn("CPU%d offline when state is online\n", cpu); |
| } |
| |
| if (state->rejected) { |
| state->rejected = false; |
| f->avail_cpus++; |
| } |
| |
| /* |
| * If a CPU is in the process of coming up, mark it as online |
| * so that there's no race with hotplug thread bringing up more |
| * CPUs than necessary. |
| */ |
| if (!f->disabled && |
| apply_limits(f, f->need_cpus) <= f->online_cpus) { |
| pr_debug("Prevent CPU%d onlining\n", cpu); |
| ret = NOTIFY_BAD; |
| } else { |
| state->online = true; |
| f->online_cpus++; |
| } |
| break; |
| |
| case CPU_ONLINE: |
| /* |
| * Moving to the end of the list should only happen in |
| * CPU_ONLINE and not on CPU_UP_PREPARE to prevent an |
| * infinite list traversal when thermal (or other entities) |
| * reject trying to online CPUs. |
| */ |
| ret = mutex_trylock(&lru_lock); |
| if (ret) { |
| spin_lock_irqsave(&state_lock, flags); |
| list_del(&state->sib); |
| list_add_tail(&state->sib, &f->lru); |
| spin_unlock_irqrestore(&state_lock, flags); |
| mutex_unlock(&lru_lock); |
| } else { |
| /* |
| * lru_lock is held by our hotplug thread to |
| * prevent concurrent access of lru list. The updates |
| * are maintained in pending_lru list and lru is |
| * updated at the end of do_hotplug(). |
| */ |
| add_to_pending_lru(state); |
| } |
| break; |
| |
| case CPU_DEAD: |
| /* Move a CPU to the end of the LRU when it goes offline. */ |
| ret = mutex_trylock(&lru_lock); |
| if (ret) { |
| spin_lock_irqsave(&state_lock, flags); |
| list_del(&state->sib); |
| list_add_tail(&state->sib, &f->lru); |
| spin_unlock_irqrestore(&state_lock, flags); |
| mutex_unlock(&lru_lock); |
| } else { |
| add_to_pending_lru(state); |
| } |
| /* Fall through */ |
| |
| case CPU_UP_CANCELED: |
| |
| /* If online state of CPU somehow got out of sync, fix it. */ |
| if (!state->online) { |
| f->online_cpus++; |
| pr_warn("CPU%d online when state is offline\n", cpu); |
| } |
| |
| if (!state->rejected && action == CPU_UP_CANCELED) { |
| state->rejected = true; |
| f->avail_cpus--; |
| } |
| |
| state->online = false; |
| state->busy = 0; |
| f->online_cpus--; |
| break; |
| } |
| |
| if (f->online_cpus < apply_limits(f, f->need_cpus) |
| && f->online_cpus < f->avail_cpus |
| && action == CPU_DEAD) |
| wake_up_hotplug_thread(f); |
| |
| return ret; |
| } |
| |
| static struct notifier_block __refdata cpu_notifier = { |
| .notifier_call = cpu_callback, |
| }; |
| |
| /* ============================ init code ============================== */ |
| |
| static int group_init(struct cpumask *mask) |
| { |
| struct device *dev; |
| unsigned int first_cpu = cpumask_first(mask); |
| struct cpu_data *f = &per_cpu(cpu_state, first_cpu); |
| struct cpu_data *state; |
| unsigned int cpu; |
| struct sched_param param = { .sched_priority = MAX_RT_PRIO-1 }; |
| |
| if (likely(f->inited)) |
| return 0; |
| |
| dev = get_cpu_device(first_cpu); |
| if (!dev) |
| return -ENODEV; |
| |
| pr_info("Creating CPU group %d\n", first_cpu); |
| |
| f->num_cpus = cpumask_weight(mask); |
| if (f->num_cpus > MAX_CPUS_PER_GROUP) { |
| pr_err("HW configuration not supported\n"); |
| return -EINVAL; |
| } |
| f->min_cpus = 1; |
| f->max_cpus = f->num_cpus; |
| f->need_cpus = f->num_cpus; |
| f->avail_cpus = f->num_cpus; |
| f->offline_delay_ms = 100; |
| f->task_thres = UINT_MAX; |
| f->nrrun = f->num_cpus; |
| INIT_LIST_HEAD(&f->lru); |
| INIT_LIST_HEAD(&f->pending_lru); |
| init_timer(&f->timer); |
| spin_lock_init(&f->pending_lock); |
| f->timer.function = core_ctl_timer_func; |
| f->timer.data = first_cpu; |
| |
| for_each_cpu(cpu, mask) { |
| pr_info("Init CPU%u state\n", cpu); |
| |
| state = &per_cpu(cpu_state, cpu); |
| state->cpu = cpu; |
| state->first_cpu = first_cpu; |
| |
| if (cpu_online(cpu)) { |
| f->online_cpus++; |
| state->online = true; |
| } |
| |
| list_add_tail(&state->sib, &f->lru); |
| INIT_LIST_HEAD(&state->pending_sib); |
| } |
| |
| f->hotplug_thread = kthread_run(try_hotplug, (void *) f, |
| "core_ctl/%d", first_cpu); |
| if (IS_ERR(f->hotplug_thread)) |
| return PTR_ERR(f->hotplug_thread); |
| sched_setscheduler_nocheck(f->hotplug_thread, SCHED_FIFO, ¶m); |
| |
| for_each_cpu(cpu, mask) { |
| state = &per_cpu(cpu_state, cpu); |
| state->inited = true; |
| } |
| |
| kobject_init(&f->kobj, &ktype_core_ctl); |
| return kobject_add(&f->kobj, &dev->kobj, "core_ctl"); |
| } |
| |
| static int cpufreq_policy_cb(struct notifier_block *nb, unsigned long val, |
| void *data) |
| { |
| struct cpufreq_policy *policy = data; |
| |
| switch (val) { |
| case CPUFREQ_CREATE_POLICY: |
| group_init(policy->related_cpus); |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block cpufreq_pol_nb = { |
| .notifier_call = cpufreq_policy_cb, |
| }; |
| |
| static int cpufreq_gov_cb(struct notifier_block *nb, unsigned long val, |
| void *data) |
| { |
| struct cpufreq_govinfo *info = data; |
| |
| switch (val) { |
| case CPUFREQ_LOAD_CHANGE: |
| core_ctl_set_busy(info->cpu, info->load); |
| break; |
| } |
| |
| return NOTIFY_OK; |
| } |
| |
| static struct notifier_block cpufreq_gov_nb = { |
| .notifier_call = cpufreq_gov_cb, |
| }; |
| |
| static int __init core_ctl_init(void) |
| { |
| struct cpufreq_policy *policy; |
| unsigned int cpu; |
| |
| register_cpu_notifier(&cpu_notifier); |
| cpufreq_register_notifier(&cpufreq_pol_nb, CPUFREQ_POLICY_NOTIFIER); |
| cpufreq_register_notifier(&cpufreq_gov_nb, CPUFREQ_GOVINFO_NOTIFIER); |
| init_timer_deferrable(&rq_avg_timer); |
| rq_avg_timer.function = rq_avg_timer_func; |
| |
| get_online_cpus(); |
| for_each_online_cpu(cpu) { |
| policy = cpufreq_cpu_get(cpu); |
| if (policy) { |
| group_init(policy->related_cpus); |
| cpufreq_cpu_put(policy); |
| } |
| } |
| put_online_cpus(); |
| mod_timer(&rq_avg_timer, round_to_nw_start()); |
| return 0; |
| } |
| |
| late_initcall(core_ctl_init); |