#include <linux/task_work.h>
#include <trace/events/sched.h>
+#include <linux/sysfs.h>
+#include <linux/vmalloc.h>
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+/* Include cpufreq header to add a notifier so that cpu frequency
+ * scaling can track the current CPU frequency
+ */
+#include <linux/cpufreq.h>
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
#include "sched.h"
+
/*
* Targeted preemption latency for CPU-bound tasks:
* (default: 6ms * (1 + ilog(ncpus)), units: nanoseconds)
return contrib + runnable_avg_yN_sum[n];
}
-/*
- * We can represent the historical contribution to runnable average as the
+#ifdef CONFIG_SCHED_HMP
+#define HMP_VARIABLE_SCALE_SHIFT 16ULL
+struct hmp_global_attr {
+ struct attribute attr;
+ ssize_t (*show)(struct kobject *kobj,
+ struct attribute *attr, char *buf);
+ ssize_t (*store)(struct kobject *a, struct attribute *b,
+ const char *c, size_t count);
+ int *value;
+ int (*to_sysfs)(int);
+ int (*from_sysfs)(int);
+ ssize_t (*to_sysfs_text)(char *buf, int buf_size);
+};
+
+#define HMP_DATA_SYSFS_MAX 8
+
+struct hmp_data_struct {
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ int freqinvar_load_scale_enabled;
+#endif
+ int multiplier; /* used to scale the time delta */
+ struct attribute_group attr_group;
+ struct attribute *attributes[HMP_DATA_SYSFS_MAX + 1];
+ struct hmp_global_attr attr[HMP_DATA_SYSFS_MAX];
+} hmp_data;
+
+static u64 hmp_variable_scale_convert(u64 delta);
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+/* Frequency-Invariant Load Modification:
+ * Loads are calculated as in PJT's patch however we also scale the current
+ * contribution in line with the frequency of the CPU that the task was
+ * executed on.
+ * In this version, we use a simple linear scale derived from the maximum
+ * frequency reported by CPUFreq. As an example:
+ *
+ * Consider that we ran a task for 100% of the previous interval.
+ *
+ * Our CPU was under asynchronous frequency control through one of the
+ * CPUFreq governors.
+ *
+ * The CPUFreq governor reports that it is able to scale the CPU between
+ * 500MHz and 1GHz.
+ *
+ * During the period, the CPU was running at 1GHz.
+ *
+ * In this case, our load contribution for that period is calculated as
+ * 1 * (number_of_active_microseconds)
+ *
+ * This results in our task being able to accumulate maximum load as normal.
+ *
+ *
+ * Consider now that our CPU was executing at 500MHz.
+ *
+ * We now scale the load contribution such that it is calculated as
+ * 0.5 * (number_of_active_microseconds)
+ *
+ * Our task can only record 50% maximum load during this period.
+ *
+ * This represents the task consuming 50% of the CPU's *possible* compute
+ * capacity. However the task did consume 100% of the CPU's *available*
+ * compute capacity which is the value seen by the CPUFreq governor and
+ * user-side CPU Utilization tools.
+ *
+ * Restricting tracked load to be scaled by the CPU's frequency accurately
+ * represents the consumption of possible compute capacity and allows the
+ * HMP migration's simple threshold migration strategy to interact more
+ * predictably with CPUFreq's asynchronous compute capacity changes.
+ */
+#define SCHED_FREQSCALE_SHIFT 10
+struct cpufreq_extents {
+ u32 curr_scale;
+ u32 min;
+ u32 max;
+ u32 flags;
+};
+/* Flag set when the governor in use only allows one frequency.
+ * Disables scaling.
+ */
+#define SCHED_LOAD_FREQINVAR_SINGLEFREQ 0x01
+
+static struct cpufreq_extents freq_scale[CONFIG_NR_CPUS];
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
+#endif /* CONFIG_SCHED_HMP */
+
+/* We can represent the historical contribution to runnable average as the
* coefficients of a geometric series. To do this we sub-divide our runnable
* history into segments of approximately 1ms (1024us); label the segment that
* occurred N-ms ago p_N, with p_0 corresponding to the current period, e.g.
*/
static __always_inline int __update_entity_runnable_avg(u64 now,
struct sched_avg *sa,
- int runnable)
+ int runnable,
+ int running,
+ int cpu)
{
u64 delta, periods;
u32 runnable_contrib;
int delta_w, decayed = 0;
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ u64 scaled_delta;
+ u32 scaled_runnable_contrib;
+ int scaled_delta_w;
+ u32 curr_scale = 1024;
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
delta = now - sa->last_runnable_update;
+#ifdef CONFIG_SCHED_HMP
+ delta = hmp_variable_scale_convert(delta);
+#endif
/*
* This should only happen when time goes backwards, which it
* unfortunately does during sched clock init when we swap over to TSC.
return 0;
sa->last_runnable_update = now;
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ /* retrieve scale factor for load */
+ if (hmp_data.freqinvar_load_scale_enabled)
+ curr_scale = freq_scale[cpu].curr_scale;
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
+
/* delta_w is the amount already accumulated against our next period */
delta_w = sa->runnable_avg_period % 1024;
if (delta + delta_w >= 1024) {
* period and accrue it.
*/
delta_w = 1024 - delta_w;
+ /* scale runnable time if necessary */
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ scaled_delta_w = (delta_w * curr_scale)
+ >> SCHED_FREQSCALE_SHIFT;
+ if (runnable)
+ sa->runnable_avg_sum += scaled_delta_w;
+ if (running)
+ sa->usage_avg_sum += scaled_delta_w;
+#else
if (runnable)
sa->runnable_avg_sum += delta_w;
+ if (running)
+ sa->usage_avg_sum += delta_w;
+#endif /* #ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
sa->runnable_avg_period += delta_w;
delta -= delta_w;
/* Figure out how many additional periods this update spans */
periods = delta / 1024;
delta %= 1024;
-
+ /* decay the load we have accumulated so far */
sa->runnable_avg_sum = decay_load(sa->runnable_avg_sum,
periods + 1);
sa->runnable_avg_period = decay_load(sa->runnable_avg_period,
periods + 1);
-
+ sa->usage_avg_sum = decay_load(sa->usage_avg_sum, periods + 1);
+ /* add the contribution from this period */
/* Efficiently calculate \sum (1..n_period) 1024*y^i */
runnable_contrib = __compute_runnable_contrib(periods);
+ /* Apply load scaling if necessary.
+ * Note that multiplying the whole series is same as
+ * multiplying all terms
+ */
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ scaled_runnable_contrib = (runnable_contrib * curr_scale)
+ >> SCHED_FREQSCALE_SHIFT;
+ if (runnable)
+ sa->runnable_avg_sum += scaled_runnable_contrib;
+ if (running)
+ sa->usage_avg_sum += scaled_runnable_contrib;
+#else
if (runnable)
sa->runnable_avg_sum += runnable_contrib;
+ if (running)
+ sa->usage_avg_sum += runnable_contrib;
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
sa->runnable_avg_period += runnable_contrib;
}
/* Remainder of delta accrued against u_0` */
+ /* scale if necessary */
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ scaled_delta = ((delta * curr_scale) >> SCHED_FREQSCALE_SHIFT);
+ if (runnable)
+ sa->runnable_avg_sum += scaled_delta;
+ if (running)
+ sa->usage_avg_sum += scaled_delta;
+#else
if (runnable)
sa->runnable_avg_sum += delta;
+ if (running)
+ sa->usage_avg_sum += delta;
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
sa->runnable_avg_period += delta;
return decayed;
u64 decays = atomic64_read(&cfs_rq->decay_counter);
decays -= se->avg.decay_count;
- if (!decays)
- return 0;
-
- se->avg.load_avg_contrib = decay_load(se->avg.load_avg_contrib, decays);
+ if (decays)
+ se->avg.load_avg_contrib = decay_load(se->avg.load_avg_contrib, decays);
se->avg.decay_count = 0;
-
return decays;
}
struct cfs_rq *cfs_rq)
{
struct task_group *tg = cfs_rq->tg;
- long contrib;
+ long contrib, usage_contrib;
/* The fraction of a cpu used by this cfs_rq */
contrib = div_u64(sa->runnable_avg_sum << NICE_0_SHIFT,
sa->runnable_avg_period + 1);
contrib -= cfs_rq->tg_runnable_contrib;
- if (abs(contrib) > cfs_rq->tg_runnable_contrib / 64) {
+ usage_contrib = div_u64(sa->usage_avg_sum << NICE_0_SHIFT,
+ sa->runnable_avg_period + 1);
+ usage_contrib -= cfs_rq->tg_usage_contrib;
+
+ /*
+ * contrib/usage at this point represent deltas, only update if they
+ * are substantive.
+ */
+ if ((abs(contrib) > cfs_rq->tg_runnable_contrib / 64) ||
+ (abs(usage_contrib) > cfs_rq->tg_usage_contrib / 64)) {
atomic_add(contrib, &tg->runnable_avg);
cfs_rq->tg_runnable_contrib += contrib;
+
+ atomic_add(usage_contrib, &tg->usage_avg);
+ cfs_rq->tg_usage_contrib += usage_contrib;
}
}
contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight);
contrib /= (se->avg.runnable_avg_period + 1);
se->avg.load_avg_contrib = scale_load(contrib);
+ trace_sched_task_load_contrib(task_of(se), se->avg.load_avg_contrib);
+ contrib = se->avg.runnable_avg_sum * scale_load_down(NICE_0_LOAD);
+ contrib /= (se->avg.runnable_avg_period + 1);
+ se->avg.load_avg_ratio = scale_load(contrib);
+ trace_sched_task_runnable_ratio(task_of(se), se->avg.load_avg_ratio);
}
/* Compute the current contribution to load_avg by se, return any delta */
-static long __update_entity_load_avg_contrib(struct sched_entity *se)
+static long __update_entity_load_avg_contrib(struct sched_entity *se, long *ratio)
{
long old_contrib = se->avg.load_avg_contrib;
+ long old_ratio = se->avg.load_avg_ratio;
if (entity_is_task(se)) {
__update_task_entity_contrib(se);
__update_group_entity_contrib(se);
}
+ if (ratio)
+ *ratio = se->avg.load_avg_ratio - old_ratio;
return se->avg.load_avg_contrib - old_contrib;
}
int update_cfs_rq)
{
struct cfs_rq *cfs_rq = cfs_rq_of(se);
- long contrib_delta;
+ long contrib_delta, ratio_delta;
u64 now;
+ int cpu = -1; /* not used in normal case */
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ cpu = cfs_rq->rq->cpu;
+#endif
/*
* For a group entity we need to use their owned cfs_rq_clock_task() in
* case they are the parent of a throttled hierarchy.
else
now = cfs_rq_clock_task(group_cfs_rq(se));
- if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq))
+ if (!__update_entity_runnable_avg(now, &se->avg, se->on_rq,
+ cfs_rq->curr == se, cpu))
return;
- contrib_delta = __update_entity_load_avg_contrib(se);
+ contrib_delta = __update_entity_load_avg_contrib(se, &ratio_delta);
if (!update_cfs_rq)
return;
- if (se->on_rq)
+ if (se->on_rq) {
cfs_rq->runnable_load_avg += contrib_delta;
- else
+ rq_of(cfs_rq)->avg.load_avg_ratio += ratio_delta;
+ } else {
subtract_blocked_load_contrib(cfs_rq, -contrib_delta);
+ }
}
/*
static inline void update_rq_runnable_avg(struct rq *rq, int runnable)
{
- __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable);
+ int cpu = -1; /* not used in normal case */
+
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ cpu = rq->cpu;
+#endif
+ __update_entity_runnable_avg(rq->clock_task, &rq->avg, runnable,
+ runnable, cpu);
__update_tg_runnable_avg(&rq->avg, &rq->cfs);
+ trace_sched_rq_runnable_ratio(cpu_of(rq), rq->avg.load_avg_ratio);
+ trace_sched_rq_runnable_load(cpu_of(rq), rq->cfs.runnable_load_avg);
+ trace_sched_rq_nr_running(cpu_of(rq), rq->nr_running, rq->nr_iowait.counter);
}
/* Add the load generated by se into cfs_rq's child load-average */
}
cfs_rq->runnable_load_avg += se->avg.load_avg_contrib;
+ rq_of(cfs_rq)->avg.load_avg_ratio += se->avg.load_avg_ratio;
+
/* we force update consideration on load-balancer moves */
update_cfs_rq_blocked_load(cfs_rq, !wakeup);
}
update_cfs_rq_blocked_load(cfs_rq, !sleep);
cfs_rq->runnable_load_avg -= se->avg.load_avg_contrib;
+ rq_of(cfs_rq)->avg.load_avg_ratio -= se->avg.load_avg_ratio;
+
if (sleep) {
cfs_rq->blocked_load_avg += se->avg.load_avg_contrib;
se->avg.decay_count = atomic64_read(&cfs_rq->decay_counter);
*/
update_stats_wait_end(cfs_rq, se);
__dequeue_entity(cfs_rq, se);
+ update_entity_load_avg(se, 1);
}
update_stats_curr_start(cfs_rq, se);
return target;
}
+#ifdef CONFIG_SCHED_HMP
+/*
+ * Heterogenous multiprocessor (HMP) optimizations
+ *
+ * The cpu types are distinguished using a list of hmp_domains
+ * which each represent one cpu type using a cpumask.
+ * The list is assumed ordered by compute capacity with the
+ * fastest domain first.
+ */
+DEFINE_PER_CPU(struct hmp_domain *, hmp_cpu_domain);
+static const int hmp_max_tasks = 5;
+
+extern void __init arch_get_hmp_domains(struct list_head *hmp_domains_list);
+
+/* Setup hmp_domains */
+static int __init hmp_cpu_mask_setup(void)
+{
+ char buf[64];
+ struct hmp_domain *domain;
+ struct list_head *pos;
+ int dc, cpu;
+
+ pr_debug("Initializing HMP scheduler:\n");
+
+ /* Initialize hmp_domains using platform code */
+ arch_get_hmp_domains(&hmp_domains);
+ if (list_empty(&hmp_domains)) {
+ pr_debug("HMP domain list is empty!\n");
+ return 0;
+ }
+
+ /* Print hmp_domains */
+ dc = 0;
+ list_for_each(pos, &hmp_domains) {
+ domain = list_entry(pos, struct hmp_domain, hmp_domains);
+ cpulist_scnprintf(buf, 64, &domain->possible_cpus);
+ pr_debug(" HMP domain %d: %s\n", dc, buf);
+
+ for_each_cpu_mask(cpu, domain->possible_cpus) {
+ per_cpu(hmp_cpu_domain, cpu) = domain;
+ }
+ dc++;
+ }
+
+ return 1;
+}
+
+static struct hmp_domain *hmp_get_hmp_domain_for_cpu(int cpu)
+{
+ struct hmp_domain *domain;
+ struct list_head *pos;
+
+ list_for_each(pos, &hmp_domains) {
+ domain = list_entry(pos, struct hmp_domain, hmp_domains);
+ if(cpumask_test_cpu(cpu, &domain->possible_cpus))
+ return domain;
+ }
+ return NULL;
+}
+
+static void hmp_online_cpu(int cpu)
+{
+ struct hmp_domain *domain = hmp_get_hmp_domain_for_cpu(cpu);
+
+ if(domain)
+ cpumask_set_cpu(cpu, &domain->cpus);
+}
+
+static void hmp_offline_cpu(int cpu)
+{
+ struct hmp_domain *domain = hmp_get_hmp_domain_for_cpu(cpu);
+
+ if(domain)
+ cpumask_clear_cpu(cpu, &domain->cpus);
+}
+/*
+ * Needed to determine heaviest tasks etc.
+ */
+static inline unsigned int hmp_cpu_is_fastest(int cpu);
+static inline unsigned int hmp_cpu_is_slowest(int cpu);
+static inline struct hmp_domain *hmp_slower_domain(int cpu);
+static inline struct hmp_domain *hmp_faster_domain(int cpu);
+
+/* must hold runqueue lock for queue se is currently on */
+static struct sched_entity *hmp_get_heaviest_task(
+ struct sched_entity *se, int migrate_up)
+{
+ int num_tasks = hmp_max_tasks;
+ struct sched_entity *max_se = se;
+ unsigned long int max_ratio = se->avg.load_avg_ratio;
+ const struct cpumask *hmp_target_mask = NULL;
+
+ if (migrate_up) {
+ struct hmp_domain *hmp;
+ if (hmp_cpu_is_fastest(cpu_of(se->cfs_rq->rq)))
+ return max_se;
+
+ hmp = hmp_faster_domain(cpu_of(se->cfs_rq->rq));
+ hmp_target_mask = &hmp->cpus;
+ }
+ /* The currently running task is not on the runqueue */
+ se = __pick_first_entity(cfs_rq_of(se));
+
+ while (num_tasks && se) {
+ if (entity_is_task(se) &&
+ (se->avg.load_avg_ratio > max_ratio &&
+ hmp_target_mask &&
+ cpumask_intersects(hmp_target_mask,
+ tsk_cpus_allowed(task_of(se))))) {
+ max_se = se;
+ max_ratio = se->avg.load_avg_ratio;
+ }
+ se = __pick_next_entity(se);
+ num_tasks--;
+ }
+ return max_se;
+}
+
+static struct sched_entity *hmp_get_lightest_task(
+ struct sched_entity *se, int migrate_down)
+{
+ int num_tasks = hmp_max_tasks;
+ struct sched_entity *min_se = se;
+ unsigned long int min_ratio = se->avg.load_avg_ratio;
+ const struct cpumask *hmp_target_mask = NULL;
+
+ if (migrate_down) {
+ struct hmp_domain *hmp;
+ if (hmp_cpu_is_slowest(cpu_of(se->cfs_rq->rq)))
+ return min_se;
+ hmp = hmp_slower_domain(cpu_of(se->cfs_rq->rq));
+ hmp_target_mask = &hmp->cpus;
+ }
+ /* The currently running task is not on the runqueue */
+ se = __pick_first_entity(cfs_rq_of(se));
+
+ while (num_tasks && se) {
+ if (entity_is_task(se) &&
+ (se->avg.load_avg_ratio < min_ratio &&
+ hmp_target_mask &&
+ cpumask_intersects(hmp_target_mask,
+ tsk_cpus_allowed(task_of(se))))) {
+ min_se = se;
+ min_ratio = se->avg.load_avg_ratio;
+ }
+ se = __pick_next_entity(se);
+ num_tasks--;
+ }
+ return min_se;
+}
+
+/*
+ * Migration thresholds should be in the range [0..1023]
+ * hmp_up_threshold: min. load required for migrating tasks to a faster cpu
+ * hmp_down_threshold: max. load allowed for tasks migrating to a slower cpu
+ *
+ * hmp_up_prio: Only up migrate task with high priority (<hmp_up_prio)
+ * hmp_next_up_threshold: Delay before next up migration (1024 ~= 1 ms)
+ * hmp_next_down_threshold: Delay before next down migration (1024 ~= 1 ms)
+ *
+ * Small Task Packing:
+ * We can choose to fill the littlest CPUs in an HMP system rather than
+ * the typical spreading mechanic. This behavior is controllable using
+ * two variables.
+ * hmp_packing_enabled: runtime control over pack/spread
+ * hmp_full_threshold: Consider a CPU with this much unweighted load full
+ */
+unsigned int hmp_up_threshold = 700;
+unsigned int hmp_down_threshold = 512;
+#ifdef CONFIG_SCHED_HMP_PRIO_FILTER
+unsigned int hmp_up_prio = NICE_TO_PRIO(CONFIG_SCHED_HMP_PRIO_FILTER_VAL);
+#endif
+unsigned int hmp_next_up_threshold = 4096;
+unsigned int hmp_next_down_threshold = 4096;
+
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+#ifndef CONFIG_ARCH_VEXPRESS_TC2
+unsigned int hmp_packing_enabled = 1;
+unsigned int hmp_full_threshold = (NICE_0_LOAD * 9) / 8;
+#else
+/* TC2 has a sharp consumption curve @ around 800Mhz, so
+ we aim to spread the load around that frequency. */
+unsigned int hmp_packing_enabled;
+unsigned int hmp_full_threshold = 650; /* 80% of the 800Mhz freq * NICE_0_LOAD */
+#endif
+#endif
+
+static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se);
+static unsigned int hmp_down_migration(int cpu, struct sched_entity *se);
+static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
+ int *min_cpu, struct cpumask *affinity);
+
+static inline struct hmp_domain *hmp_smallest_domain(void)
+{
+ return list_entry(hmp_domains.prev, struct hmp_domain, hmp_domains);
+}
+
+/* Check if cpu is in fastest hmp_domain */
+static inline unsigned int hmp_cpu_is_fastest(int cpu)
+{
+ struct list_head *pos;
+
+ pos = &hmp_cpu_domain(cpu)->hmp_domains;
+ return pos == hmp_domains.next;
+}
+
+/* Check if cpu is in slowest hmp_domain */
+static inline unsigned int hmp_cpu_is_slowest(int cpu)
+{
+ struct list_head *pos;
+
+ pos = &hmp_cpu_domain(cpu)->hmp_domains;
+ return list_is_last(pos, &hmp_domains);
+}
+
+/* Next (slower) hmp_domain relative to cpu */
+static inline struct hmp_domain *hmp_slower_domain(int cpu)
+{
+ struct list_head *pos;
+
+ pos = &hmp_cpu_domain(cpu)->hmp_domains;
+ return list_entry(pos->next, struct hmp_domain, hmp_domains);
+}
+
+/* Previous (faster) hmp_domain relative to cpu */
+static inline struct hmp_domain *hmp_faster_domain(int cpu)
+{
+ struct list_head *pos;
+
+ pos = &hmp_cpu_domain(cpu)->hmp_domains;
+ return list_entry(pos->prev, struct hmp_domain, hmp_domains);
+}
+
+/*
+ * Selects a cpu in previous (faster) hmp_domain
+ */
+static inline unsigned int hmp_select_faster_cpu(struct task_struct *tsk,
+ int cpu)
+{
+ int lowest_cpu=NR_CPUS;
+ __always_unused int lowest_ratio;
+ struct hmp_domain *hmp;
+
+ if (hmp_cpu_is_fastest(cpu))
+ hmp = hmp_cpu_domain(cpu);
+ else
+ hmp = hmp_faster_domain(cpu);
+
+ lowest_ratio = hmp_domain_min_load(hmp, &lowest_cpu,
+ tsk_cpus_allowed(tsk));
+
+ return lowest_cpu;
+}
+
+/*
+ * Selects a cpu in next (slower) hmp_domain
+ * Note that cpumask_any_and() returns the first cpu in the cpumask
+ */
+static inline unsigned int hmp_select_slower_cpu(struct task_struct *tsk,
+ int cpu)
+{
+ int lowest_cpu=NR_CPUS;
+ struct hmp_domain *hmp;
+ __always_unused int lowest_ratio;
+
+ if (hmp_cpu_is_slowest(cpu))
+ hmp = hmp_cpu_domain(cpu);
+ else
+ hmp = hmp_slower_domain(cpu);
+
+ lowest_ratio = hmp_domain_min_load(hmp, &lowest_cpu,
+ tsk_cpus_allowed(tsk));
+
+ return lowest_cpu;
+}
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+/*
+ * Select the 'best' candidate little CPU to wake up on.
+ * Implements a packing strategy which examines CPU in
+ * logical CPU order, and selects the first which will
+ * have at least 10% capacity available, according to
+ * both tracked load of the runqueue and the task.
+ */
+static inline unsigned int hmp_best_little_cpu(struct task_struct *tsk,
+ int cpu) {
+ int tmp_cpu;
+ unsigned long estimated_load;
+ struct hmp_domain *hmp;
+ struct sched_avg *avg;
+ struct cpumask allowed_hmp_cpus;
+
+ if(!hmp_packing_enabled ||
+ tsk->se.avg.load_avg_ratio > ((NICE_0_LOAD * 90)/100))
+ return hmp_select_slower_cpu(tsk, cpu);
+
+ if (hmp_cpu_is_slowest(cpu))
+ hmp = hmp_cpu_domain(cpu);
+ else
+ hmp = hmp_slower_domain(cpu);
+
+ /* respect affinity */
+ cpumask_and(&allowed_hmp_cpus, &hmp->cpus,
+ tsk_cpus_allowed(tsk));
+
+ for_each_cpu_mask(tmp_cpu, allowed_hmp_cpus) {
+ avg = &cpu_rq(tmp_cpu)->avg;
+ /* estimate new rq load if we add this task */
+ estimated_load = avg->load_avg_ratio +
+ tsk->se.avg.load_avg_ratio;
+ if (estimated_load <= hmp_full_threshold) {
+ cpu = tmp_cpu;
+ break;
+ }
+ }
+ /* if no match was found, the task uses the initial value */
+ return cpu;
+}
+#endif
+static inline void hmp_next_up_delay(struct sched_entity *se, int cpu)
+{
+ /* hack - always use clock from first online CPU */
+ u64 now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
+ se->avg.hmp_last_up_migration = now;
+ se->avg.hmp_last_down_migration = 0;
+ cpu_rq(cpu)->avg.hmp_last_up_migration = now;
+ cpu_rq(cpu)->avg.hmp_last_down_migration = 0;
+}
+
+static inline void hmp_next_down_delay(struct sched_entity *se, int cpu)
+{
+ /* hack - always use clock from first online CPU */
+ u64 now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
+ se->avg.hmp_last_down_migration = now;
+ se->avg.hmp_last_up_migration = 0;
+ cpu_rq(cpu)->avg.hmp_last_down_migration = now;
+ cpu_rq(cpu)->avg.hmp_last_up_migration = 0;
+}
+
+/*
+ * Heterogenous multiprocessor (HMP) optimizations
+ *
+ * These functions allow to change the growing speed of the load_avg_ratio
+ * by default it goes from 0 to 0.5 in LOAD_AVG_PERIOD = 32ms
+ * This can now be changed with /sys/kernel/hmp/load_avg_period_ms.
+ *
+ * These functions also allow to change the up and down threshold of HMP
+ * using /sys/kernel/hmp/{up,down}_threshold.
+ * Both must be between 0 and 1023. The threshold that is compared
+ * to the load_avg_ratio is up_threshold/1024 and down_threshold/1024.
+ *
+ * For instance, if load_avg_period = 64 and up_threshold = 512, an idle
+ * task with a load of 0 will reach the threshold after 64ms of busy loop.
+ *
+ * Changing load_avg_periods_ms has the same effect than changing the
+ * default scaling factor Y=1002/1024 in the load_avg_ratio computation to
+ * (1002/1024.0)^(LOAD_AVG_PERIOD/load_avg_period_ms), but the last one
+ * could trigger overflows.
+ * For instance, with Y = 1023/1024 in __update_task_entity_contrib()
+ * "contrib = se->avg.runnable_avg_sum * scale_load_down(se->load.weight);"
+ * could be overflowed for a weight > 2^12 even is the load_avg_contrib
+ * should still be a 32bits result. This would not happen by multiplicating
+ * delta time by 1/22 and setting load_avg_period_ms = 706.
+ */
+
+/*
+ * By scaling the delta time it end-up increasing or decrease the
+ * growing speed of the per entity load_avg_ratio
+ * The scale factor hmp_data.multiplier is a fixed point
+ * number: (32-HMP_VARIABLE_SCALE_SHIFT).HMP_VARIABLE_SCALE_SHIFT
+ */
+static inline u64 hmp_variable_scale_convert(u64 delta)
+{
+#ifdef CONFIG_HMP_VARIABLE_SCALE
+ u64 high = delta >> 32ULL;
+ u64 low = delta & 0xffffffffULL;
+ low *= hmp_data.multiplier;
+ high *= hmp_data.multiplier;
+ return (low >> HMP_VARIABLE_SCALE_SHIFT)
+ + (high << (32ULL - HMP_VARIABLE_SCALE_SHIFT));
+#else
+ return delta;
+#endif
+}
+
+static ssize_t hmp_show(struct kobject *kobj,
+ struct attribute *attr, char *buf)
+{
+ struct hmp_global_attr *hmp_attr =
+ container_of(attr, struct hmp_global_attr, attr);
+ int temp;
+
+ if (hmp_attr->to_sysfs_text != NULL)
+ return hmp_attr->to_sysfs_text(buf, PAGE_SIZE);
+
+ temp = *(hmp_attr->value);
+ if (hmp_attr->to_sysfs != NULL)
+ temp = hmp_attr->to_sysfs(temp);
+
+ return (ssize_t)sprintf(buf, "%d\n", temp);
+}
+
+static ssize_t hmp_store(struct kobject *a, struct attribute *attr,
+ const char *buf, size_t count)
+{
+ int temp;
+ ssize_t ret = count;
+ struct hmp_global_attr *hmp_attr =
+ container_of(attr, struct hmp_global_attr, attr);
+ char *str = vmalloc(count + 1);
+ if (str == NULL)
+ return -ENOMEM;
+ memcpy(str, buf, count);
+ str[count] = 0;
+ if (sscanf(str, "%d", &temp) < 1)
+ ret = -EINVAL;
+ else {
+ if (hmp_attr->from_sysfs != NULL)
+ temp = hmp_attr->from_sysfs(temp);
+ if (temp < 0)
+ ret = -EINVAL;
+ else
+ *(hmp_attr->value) = temp;
+ }
+ vfree(str);
+ return ret;
+}
+
+static ssize_t hmp_print_domains(char *outbuf, int outbufsize)
+{
+ char buf[64];
+ const char nospace[] = "%s", space[] = " %s";
+ const char *fmt = nospace;
+ struct hmp_domain *domain;
+ struct list_head *pos;
+ int outpos = 0;
+ list_for_each(pos, &hmp_domains) {
+ domain = list_entry(pos, struct hmp_domain, hmp_domains);
+ if (cpumask_scnprintf(buf, 64, &domain->possible_cpus)) {
+ outpos += sprintf(outbuf+outpos, fmt, buf);
+ fmt = space;
+ }
+ }
+ strcat(outbuf, "\n");
+ return outpos+1;
+}
+
+#ifdef CONFIG_HMP_VARIABLE_SCALE
+static int hmp_period_tofrom_sysfs(int value)
+{
+ return (LOAD_AVG_PERIOD << HMP_VARIABLE_SCALE_SHIFT) / value;
+}
+#endif
+/* max value for threshold is 1024 */
+static int hmp_theshold_from_sysfs(int value)
+{
+ if (value > 1024)
+ return -1;
+ return value;
+}
+#if defined(CONFIG_SCHED_HMP_LITTLE_PACKING) || \
+ defined(CONFIG_HMP_FREQUENCY_INVARIANT_SCALE)
+/* toggle control is only 0,1 off/on */
+static int hmp_toggle_from_sysfs(int value)
+{
+ if (value < 0 || value > 1)
+ return -1;
+ return value;
+}
+#endif
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+/* packing value must be non-negative */
+static int hmp_packing_from_sysfs(int value)
+{
+ if (value < 0)
+ return -1;
+ return value;
+}
+#endif
+static void hmp_attr_add(
+ const char *name,
+ int *value,
+ int (*to_sysfs)(int),
+ int (*from_sysfs)(int),
+ ssize_t (*to_sysfs_text)(char *, int),
+ umode_t mode)
+{
+ int i = 0;
+ while (hmp_data.attributes[i] != NULL) {
+ i++;
+ if (i >= HMP_DATA_SYSFS_MAX)
+ return;
+ }
+ if (mode)
+ hmp_data.attr[i].attr.mode = mode;
+ else
+ hmp_data.attr[i].attr.mode = 0644;
+ hmp_data.attr[i].show = hmp_show;
+ hmp_data.attr[i].store = hmp_store;
+ hmp_data.attr[i].attr.name = name;
+ hmp_data.attr[i].value = value;
+ hmp_data.attr[i].to_sysfs = to_sysfs;
+ hmp_data.attr[i].from_sysfs = from_sysfs;
+ hmp_data.attr[i].to_sysfs_text = to_sysfs_text;
+ hmp_data.attributes[i] = &hmp_data.attr[i].attr;
+ hmp_data.attributes[i + 1] = NULL;
+}
+
+static int hmp_attr_init(void)
+{
+ int ret;
+ memset(&hmp_data, sizeof(hmp_data), 0);
+ hmp_attr_add("hmp_domains",
+ NULL,
+ NULL,
+ NULL,
+ hmp_print_domains,
+ 0444);
+ hmp_attr_add("up_threshold",
+ &hmp_up_threshold,
+ NULL,
+ hmp_theshold_from_sysfs,
+ NULL,
+ 0);
+ hmp_attr_add("down_threshold",
+ &hmp_down_threshold,
+ NULL,
+ hmp_theshold_from_sysfs,
+ NULL,
+ 0);
+#ifdef CONFIG_HMP_VARIABLE_SCALE
+ /* by default load_avg_period_ms == LOAD_AVG_PERIOD
+ * meaning no change
+ */
+ hmp_data.multiplier = hmp_period_tofrom_sysfs(LOAD_AVG_PERIOD);
+ hmp_attr_add("load_avg_period_ms",
+ &hmp_data.multiplier,
+ hmp_period_tofrom_sysfs,
+ hmp_period_tofrom_sysfs,
+ NULL,
+ 0);
+#endif
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+ /* default frequency-invariant scaling ON */
+ hmp_data.freqinvar_load_scale_enabled = 1;
+ hmp_attr_add("frequency_invariant_load_scale",
+ &hmp_data.freqinvar_load_scale_enabled,
+ NULL,
+ hmp_toggle_from_sysfs,
+ NULL,
+ 0);
+#endif
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+ hmp_attr_add("packing_enable",
+ &hmp_packing_enabled,
+ NULL,
+ hmp_toggle_from_sysfs,
+ NULL,
+ 0);
+ hmp_attr_add("packing_limit",
+ &hmp_full_threshold,
+ NULL,
+ hmp_packing_from_sysfs,
+ NULL,
+ 0);
+#endif
+ hmp_data.attr_group.name = "hmp";
+ hmp_data.attr_group.attrs = hmp_data.attributes;
+ ret = sysfs_create_group(kernel_kobj,
+ &hmp_data.attr_group);
+ return 0;
+}
+late_initcall(hmp_attr_init);
+/*
+ * return the load of the lowest-loaded CPU in a given HMP domain
+ * min_cpu optionally points to an int to receive the CPU.
+ * affinity optionally points to a cpumask containing the
+ * CPUs to be considered. note:
+ * + min_cpu = NR_CPUS only if no CPUs are in the set of
+ * affinity && hmp_domain cpus
+ * + min_cpu will always otherwise equal one of the CPUs in
+ * the hmp domain
+ * + when more than one CPU has the same load, the one which
+ * is least-recently-disturbed by an HMP migration will be
+ * selected
+ * + if all CPUs are equally loaded or idle and the times are
+ * all the same, the first in the set will be used
+ * + if affinity is not set, cpu_online_mask is used
+ */
+static inline unsigned int hmp_domain_min_load(struct hmp_domain *hmpd,
+ int *min_cpu, struct cpumask *affinity)
+{
+ int cpu;
+ int min_cpu_runnable_temp = NR_CPUS;
+ u64 min_target_last_migration = ULLONG_MAX;
+ u64 curr_last_migration;
+ unsigned long min_runnable_load = INT_MAX;
+ unsigned long contrib;
+ struct sched_avg *avg;
+ struct cpumask temp_cpumask;
+ /*
+ * only look at CPUs allowed if specified,
+ * otherwise look at all online CPUs in the
+ * right HMP domain
+ */
+ cpumask_and(&temp_cpumask, &hmpd->cpus, affinity ? affinity : cpu_online_mask);
+
+ for_each_cpu_mask(cpu, temp_cpumask) {
+ avg = &cpu_rq(cpu)->avg;
+ /* used for both up and down migration */
+ curr_last_migration = avg->hmp_last_up_migration ?
+ avg->hmp_last_up_migration : avg->hmp_last_down_migration;
+
+ contrib = avg->load_avg_ratio;
+ /*
+ * Consider a runqueue completely busy if there is any load
+ * on it. Definitely not the best for overall fairness, but
+ * does well in typical Android use cases.
+ */
+ if (contrib)
+ contrib = 1023;
+
+ if ((contrib < min_runnable_load) ||
+ (contrib == min_runnable_load &&
+ curr_last_migration < min_target_last_migration)) {
+ /*
+ * if the load is the same target the CPU with
+ * the longest time since a migration.
+ * This is to spread migration load between
+ * members of a domain more evenly when the
+ * domain is fully loaded
+ */
+ min_runnable_load = contrib;
+ min_cpu_runnable_temp = cpu;
+ min_target_last_migration = curr_last_migration;
+ }
+ }
+
+ if (min_cpu)
+ *min_cpu = min_cpu_runnable_temp;
+
+ return min_runnable_load;
+}
+
+/*
+ * Calculate the task starvation
+ * This is the ratio of actually running time vs. runnable time.
+ * If the two are equal the task is getting the cpu time it needs or
+ * it is alone on the cpu and the cpu is fully utilized.
+ */
+static inline unsigned int hmp_task_starvation(struct sched_entity *se)
+{
+ u32 starvation;
+
+ starvation = se->avg.usage_avg_sum * scale_load_down(NICE_0_LOAD);
+ starvation /= (se->avg.runnable_avg_sum + 1);
+
+ return scale_load(starvation);
+}
+
+static inline unsigned int hmp_offload_down(int cpu, struct sched_entity *se)
+{
+ int min_usage;
+ int dest_cpu = NR_CPUS;
+
+ if (hmp_cpu_is_slowest(cpu))
+ return NR_CPUS;
+
+ /* Is there an idle CPU in the current domain */
+ min_usage = hmp_domain_min_load(hmp_cpu_domain(cpu), NULL, NULL);
+ if (min_usage == 0) {
+ trace_sched_hmp_offload_abort(cpu, min_usage, "load");
+ return NR_CPUS;
+ }
+
+ /* Is the task alone on the cpu? */
+ if (cpu_rq(cpu)->cfs.h_nr_running < 2) {
+ trace_sched_hmp_offload_abort(cpu,
+ cpu_rq(cpu)->cfs.h_nr_running, "nr_running");
+ return NR_CPUS;
+ }
+
+ /* Is the task actually starving? */
+ /* >=25% ratio running/runnable = starving */
+ if (hmp_task_starvation(se) > 768) {
+ trace_sched_hmp_offload_abort(cpu, hmp_task_starvation(se),
+ "starvation");
+ return NR_CPUS;
+ }
+
+ /* Does the slower domain have any idle CPUs? */
+ min_usage = hmp_domain_min_load(hmp_slower_domain(cpu), &dest_cpu,
+ tsk_cpus_allowed(task_of(se)));
+
+ if (min_usage == 0) {
+ trace_sched_hmp_offload_succeed(cpu, dest_cpu);
+ return dest_cpu;
+ } else
+ trace_sched_hmp_offload_abort(cpu,min_usage,"slowdomain");
+ return NR_CPUS;
+}
+#endif /* CONFIG_SCHED_HMP */
+
/*
* sched_balance_self: balance the current task (running on cpu) in domains
* that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and
if (p->nr_cpus_allowed == 1)
return prev_cpu;
+#ifdef CONFIG_SCHED_HMP
+ /* always put non-kernel forking tasks on a big domain */
+ if (p->mm && (sd_flag & SD_BALANCE_FORK)) {
+ new_cpu = hmp_select_faster_cpu(p, prev_cpu);
+ if (new_cpu != NR_CPUS) {
+ hmp_next_up_delay(&p->se, new_cpu);
+ return new_cpu;
+ }
+ /* failed to perform HMP fork balance, use normal balance */
+ new_cpu = cpu;
+ }
+#endif
+
if (sd_flag & SD_BALANCE_WAKE) {
if (cpumask_test_cpu(cpu, tsk_cpus_allowed(p)))
want_affine = 1;
unlock:
rcu_read_unlock();
- return new_cpu;
-}
+#ifdef CONFIG_SCHED_HMP
+ prev_cpu = task_cpu(p);
-/*
- * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
+ if (hmp_up_migration(prev_cpu, &new_cpu, &p->se)) {
+ hmp_next_up_delay(&p->se, new_cpu);
+ trace_sched_hmp_migrate(p, new_cpu, HMP_MIGRATE_WAKEUP);
+ return new_cpu;
+ }
+ if (hmp_down_migration(prev_cpu, &p->se)) {
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+ new_cpu = hmp_best_little_cpu(p, prev_cpu);
+#else
+ new_cpu = hmp_select_slower_cpu(p, prev_cpu);
+#endif
+ if (new_cpu != prev_cpu) {
+ hmp_next_down_delay(&p->se, new_cpu);
+ trace_sched_hmp_migrate(p, new_cpu, HMP_MIGRATE_WAKEUP);
+ return new_cpu;
+ }
+ }
+ /* Make sure that the task stays in its previous hmp domain */
+ if (!cpumask_test_cpu(new_cpu, &hmp_cpu_domain(prev_cpu)->cpus))
+ return prev_cpu;
+#endif
+
+ return new_cpu;
+}
+
+/*
+ * Load-tracking only depends on SMP, FAIR_GROUP_SCHED dependency below may be
* removed when useful for applications beyond shares distribution (e.g.
* load-balance).
*/
#ifdef CONFIG_FAIR_GROUP_SCHED
+
+#ifdef CONFIG_NO_HZ_COMMON
+static int nohz_test_cpu(int cpu);
+#else
+static inline int nohz_test_cpu(int cpu)
+{
+ return 0;
+}
+#endif
+
/*
* Called immediately before a task is migrated to a new cpu; task_cpu(p) and
* cfs_rq_of(p) references at time of call are still valid and identify the
* be negative here since on-rq tasks have decay-count == 0.
*/
if (se->avg.decay_count) {
+ /*
+ * If we migrate a sleeping task away from a CPU
+ * which has the tick stopped, then both the clock_task
+ * and decay_counter will be out of date for that CPU
+ * and we will not decay load correctly.
+ */
+ if (!se->on_rq && nohz_test_cpu(task_cpu(p))) {
+ struct rq *rq = cpu_rq(task_cpu(p));
+ unsigned long flags;
+ /*
+ * Current CPU cannot be holding rq->lock in this
+ * circumstance, but another might be. We must hold
+ * rq->lock before we go poking around in its clocks
+ */
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ update_rq_clock(rq);
+ update_cfs_rq_blocked_load(cfs_rq, 0);
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+ }
se->avg.decay_count = -__synchronize_entity_decay(se);
atomic64_add(se->avg.load_avg_contrib, &cfs_rq->removed_load);
}
* 1) task is cache cold, or
* 2) too many balance attempts have failed.
*/
-
tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
if (!tsk_cache_hot ||
env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
out:
return ld_moved;
}
-
+#ifdef CONFIG_SCHED_HMP
+static unsigned int hmp_idle_pull(int this_cpu);
+#endif
/*
* idle_balance is called by schedule() if this_cpu is about to become
* idle. Attempts to pull tasks from other CPUs.
}
}
rcu_read_unlock();
-
+#ifdef CONFIG_SCHED_HMP
+ if (!pulled_task)
+ pulled_task = hmp_idle_pull(this_cpu);
+#endif
raw_spin_lock(&this_rq->lock);
if (pulled_task || time_after(jiffies, this_rq->next_balance)) {
unsigned long next_balance; /* in jiffy units */
} nohz ____cacheline_aligned;
+/*
+ * nohz_test_cpu used when load tracking is enabled. FAIR_GROUP_SCHED
+ * dependency below may be removed when load tracking guards are
+ * removed.
+ */
+#ifdef CONFIG_FAIR_GROUP_SCHED
+static int nohz_test_cpu(int cpu)
+{
+ return cpumask_test_cpu(cpu, nohz.idle_cpus_mask);
+}
+#endif
+
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+/*
+ * Decide if the tasks on the busy CPUs in the
+ * littlest domain would benefit from an idle balance
+ */
+static int hmp_packing_ilb_needed(int cpu)
+{
+ struct hmp_domain *hmp;
+ /* always allow ilb on non-slowest domain */
+ if (!hmp_cpu_is_slowest(cpu))
+ return 1;
+
+ /* if disabled, use normal ILB behaviour */
+ if (!hmp_packing_enabled)
+ return 1;
+
+ hmp = hmp_cpu_domain(cpu);
+ for_each_cpu_and(cpu, &hmp->cpus, nohz.idle_cpus_mask) {
+ /* only idle balance if a CPU is loaded over threshold */
+ if (cpu_rq(cpu)->avg.load_avg_ratio > hmp_full_threshold)
+ return 1;
+ }
+ return 0;
+}
+#endif
+
static inline int find_new_ilb(int call_cpu)
{
int ilb = cpumask_first(nohz.idle_cpus_mask);
+#ifdef CONFIG_SCHED_HMP
+ int ilb_needed = 1;
+
+ /* restrict nohz balancing to occur in the same hmp domain */
+ ilb = cpumask_first_and(nohz.idle_cpus_mask,
+ &((struct hmp_domain *)hmp_cpu_domain(call_cpu))->cpus);
+
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+ if (ilb < nr_cpu_ids)
+ ilb_needed = hmp_packing_ilb_needed(ilb);
+#endif
+ if (ilb_needed && ilb < nr_cpu_ids && idle_cpu(ilb))
+ return ilb;
+#else
if (ilb < nr_cpu_ids && idle_cpu(ilb))
return ilb;
+#endif
return nr_cpu_ids;
}
if (time_before(now, nohz.next_balance))
return 0;
+#ifdef CONFIG_SCHED_HMP
+ /*
+ * Bail out if there are no nohz CPUs in our
+ * HMP domain, since we will move tasks between
+ * domains through wakeup and force balancing
+ * as necessary based upon task load.
+ */
+ if (cpumask_first_and(nohz.idle_cpus_mask,
+ &((struct hmp_domain *)hmp_cpu_domain(cpu))->cpus) >= nr_cpu_ids)
+ return 0;
+#endif
+
if (rq->nr_running >= 2)
goto need_kick;
static void nohz_idle_balance(int this_cpu, enum cpu_idle_type idle) { }
#endif
+#ifdef CONFIG_SCHED_HMP
+/* Check if task should migrate to a faster cpu */
+static unsigned int hmp_up_migration(int cpu, int *target_cpu, struct sched_entity *se)
+{
+ struct task_struct *p = task_of(se);
+ int temp_target_cpu;
+ u64 now;
+
+ if (hmp_cpu_is_fastest(cpu))
+ return 0;
+
+#ifdef CONFIG_SCHED_HMP_PRIO_FILTER
+ /* Filter by task priority */
+ if (p->prio >= hmp_up_prio)
+ return 0;
+#endif
+ if (se->avg.load_avg_ratio < hmp_up_threshold)
+ return 0;
+
+ /* Let the task load settle before doing another up migration */
+ /* hack - always use clock from first online CPU */
+ now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
+ if (((now - se->avg.hmp_last_up_migration) >> 10)
+ < hmp_next_up_threshold)
+ return 0;
+
+ /* hmp_domain_min_load only returns 0 for an
+ * idle CPU or 1023 for any partly-busy one.
+ * Be explicit about requirement for an idle CPU.
+ */
+ if (hmp_domain_min_load(hmp_faster_domain(cpu), &temp_target_cpu,
+ tsk_cpus_allowed(p)) == 0 && temp_target_cpu != NR_CPUS) {
+ if(target_cpu)
+ *target_cpu = temp_target_cpu;
+ return 1;
+ }
+ return 0;
+}
+
+/* Check if task should migrate to a slower cpu */
+static unsigned int hmp_down_migration(int cpu, struct sched_entity *se)
+{
+ struct task_struct *p = task_of(se);
+ u64 now;
+
+ if (hmp_cpu_is_slowest(cpu)) {
+#ifdef CONFIG_SCHED_HMP_LITTLE_PACKING
+ if(hmp_packing_enabled)
+ return 1;
+ else
+#endif
+ return 0;
+ }
+
+#ifdef CONFIG_SCHED_HMP_PRIO_FILTER
+ /* Filter by task priority */
+ if ((p->prio >= hmp_up_prio) &&
+ cpumask_intersects(&hmp_slower_domain(cpu)->cpus,
+ tsk_cpus_allowed(p))) {
+ return 1;
+ }
+#endif
+
+ /* Let the task load settle before doing another down migration */
+ /* hack - always use clock from first online CPU */
+ now = cpu_rq(cpumask_first(cpu_online_mask))->clock_task;
+ if (((now - se->avg.hmp_last_down_migration) >> 10)
+ < hmp_next_down_threshold)
+ return 0;
+
+ if (cpumask_intersects(&hmp_slower_domain(cpu)->cpus,
+ tsk_cpus_allowed(p))
+ && se->avg.load_avg_ratio < hmp_down_threshold) {
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * hmp_can_migrate_task - may task p from runqueue rq be migrated to this_cpu?
+ * Ideally this function should be merged with can_migrate_task() to avoid
+ * redundant code.
+ */
+static int hmp_can_migrate_task(struct task_struct *p, struct lb_env *env)
+{
+ int tsk_cache_hot = 0;
+
+ /*
+ * We do not migrate tasks that are:
+ * 1) running (obviously), or
+ * 2) cannot be migrated to this CPU due to cpus_allowed
+ */
+ if (!cpumask_test_cpu(env->dst_cpu, tsk_cpus_allowed(p))) {
+ schedstat_inc(p, se.statistics.nr_failed_migrations_affine);
+ return 0;
+ }
+ env->flags &= ~LBF_ALL_PINNED;
+
+ if (task_running(env->src_rq, p)) {
+ schedstat_inc(p, se.statistics.nr_failed_migrations_running);
+ return 0;
+ }
+
+ /*
+ * Aggressive migration if:
+ * 1) task is cache cold, or
+ * 2) too many balance attempts have failed.
+ */
+
+ tsk_cache_hot = task_hot(p, env->src_rq->clock_task, env->sd);
+ if (!tsk_cache_hot ||
+ env->sd->nr_balance_failed > env->sd->cache_nice_tries) {
+#ifdef CONFIG_SCHEDSTATS
+ if (tsk_cache_hot) {
+ schedstat_inc(env->sd, lb_hot_gained[env->idle]);
+ schedstat_inc(p, se.statistics.nr_forced_migrations);
+ }
+#endif
+ return 1;
+ }
+
+ return 1;
+}
+
+/*
+ * move_specific_task tries to move a specific task.
+ * Returns 1 if successful and 0 otherwise.
+ * Called with both runqueues locked.
+ */
+static int move_specific_task(struct lb_env *env, struct task_struct *pm)
+{
+ struct task_struct *p, *n;
+
+ list_for_each_entry_safe(p, n, &env->src_rq->cfs_tasks, se.group_node) {
+ if (throttled_lb_pair(task_group(p), env->src_rq->cpu,
+ env->dst_cpu))
+ continue;
+
+ if (!hmp_can_migrate_task(p, env))
+ continue;
+ /* Check if we found the right task */
+ if (p != pm)
+ continue;
+
+ move_task(p, env);
+ /*
+ * Right now, this is only the third place move_task()
+ * is called, so we can safely collect move_task()
+ * stats here rather than inside move_task().
+ */
+ schedstat_inc(env->sd, lb_gained[env->idle]);
+ return 1;
+ }
+ return 0;
+}
+
+/*
+ * hmp_active_task_migration_cpu_stop is run by cpu stopper and used to
+ * migrate a specific task from one runqueue to another.
+ * hmp_force_up_migration uses this to push a currently running task
+ * off a runqueue.
+ * Based on active_load_balance_stop_cpu and can potentially be merged.
+ */
+static int hmp_active_task_migration_cpu_stop(void *data)
+{
+ struct rq *busiest_rq = data;
+ struct task_struct *p = busiest_rq->migrate_task;
+ int busiest_cpu = cpu_of(busiest_rq);
+ int target_cpu = busiest_rq->push_cpu;
+ struct rq *target_rq = cpu_rq(target_cpu);
+ struct sched_domain *sd;
+
+ raw_spin_lock_irq(&busiest_rq->lock);
+ /* make sure the requested cpu hasn't gone down in the meantime */
+ if (unlikely(busiest_cpu != smp_processor_id() ||
+ !busiest_rq->active_balance)) {
+ goto out_unlock;
+ }
+ /* Is there any task to move? */
+ if (busiest_rq->nr_running <= 1)
+ goto out_unlock;
+ /* Task has migrated meanwhile, abort forced migration */
+ if (task_rq(p) != busiest_rq)
+ goto out_unlock;
+ /*
+ * This condition is "impossible", if it occurs
+ * we need to fix it. Originally reported by
+ * Bjorn Helgaas on a 128-cpu setup.
+ */
+ BUG_ON(busiest_rq == target_rq);
+
+ /* move a task from busiest_rq to target_rq */
+ double_lock_balance(busiest_rq, target_rq);
+
+ /* Search for an sd spanning us and the target CPU. */
+ rcu_read_lock();
+ for_each_domain(target_cpu, sd) {
+ if (cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+ break;
+ }
+
+ if (likely(sd)) {
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = target_cpu,
+ .dst_rq = target_rq,
+ .src_cpu = busiest_rq->cpu,
+ .src_rq = busiest_rq,
+ .idle = CPU_IDLE,
+ };
+
+ schedstat_inc(sd, alb_count);
+
+ if (move_specific_task(&env, p))
+ schedstat_inc(sd, alb_pushed);
+ else
+ schedstat_inc(sd, alb_failed);
+ }
+ rcu_read_unlock();
+ double_unlock_balance(busiest_rq, target_rq);
+out_unlock:
+ put_task_struct(p);
+ busiest_rq->active_balance = 0;
+ raw_spin_unlock_irq(&busiest_rq->lock);
+ return 0;
+}
+
+/*
+ * hmp_idle_pull_cpu_stop is run by cpu stopper and used to
+ * migrate a specific task from one runqueue to another.
+ * hmp_idle_pull uses this to push a currently running task
+ * off a runqueue to a faster CPU.
+ * Locking is slightly different than usual.
+ * Based on active_load_balance_stop_cpu and can potentially be merged.
+ */
+static int hmp_idle_pull_cpu_stop(void *data)
+{
+ struct rq *busiest_rq = data;
+ struct task_struct *p = busiest_rq->migrate_task;
+ int busiest_cpu = cpu_of(busiest_rq);
+ int target_cpu = busiest_rq->push_cpu;
+ struct rq *target_rq = cpu_rq(target_cpu);
+ struct sched_domain *sd;
+
+ raw_spin_lock_irq(&busiest_rq->lock);
+
+ /* make sure the requested cpu hasn't gone down in the meantime */
+ if (unlikely(busiest_cpu != smp_processor_id() ||
+ !busiest_rq->active_balance))
+ goto out_unlock;
+
+ /* Is there any task to move? */
+ if (busiest_rq->nr_running <= 1)
+ goto out_unlock;
+
+ /* Task has migrated meanwhile, abort forced migration */
+ if (task_rq(p) != busiest_rq)
+ goto out_unlock;
+
+ /*
+ * This condition is "impossible", if it occurs
+ * we need to fix it. Originally reported by
+ * Bjorn Helgaas on a 128-cpu setup.
+ */
+ BUG_ON(busiest_rq == target_rq);
+
+ /* move a task from busiest_rq to target_rq */
+ double_lock_balance(busiest_rq, target_rq);
+
+ /* Search for an sd spanning us and the target CPU. */
+ rcu_read_lock();
+ for_each_domain(target_cpu, sd) {
+ if (cpumask_test_cpu(busiest_cpu, sched_domain_span(sd)))
+ break;
+ }
+ if (likely(sd)) {
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = target_cpu,
+ .dst_rq = target_rq,
+ .src_cpu = busiest_rq->cpu,
+ .src_rq = busiest_rq,
+ .idle = CPU_IDLE,
+ };
+
+ schedstat_inc(sd, alb_count);
+
+ if (move_specific_task(&env, p))
+ schedstat_inc(sd, alb_pushed);
+ else
+ schedstat_inc(sd, alb_failed);
+ }
+ rcu_read_unlock();
+ double_unlock_balance(busiest_rq, target_rq);
+out_unlock:
+ put_task_struct(p);
+ busiest_rq->active_balance = 0;
+ raw_spin_unlock_irq(&busiest_rq->lock);
+ return 0;
+}
+
+/*
+ * Move task in a runnable state to another CPU.
+ *
+ * Tailored on 'active_load_balance_stop_cpu' with slight
+ * modification to locking and pre-transfer checks. Note
+ * rq->lock must be held before calling.
+ */
+static void hmp_migrate_runnable_task(struct rq *rq)
+{
+ struct sched_domain *sd;
+ int src_cpu = cpu_of(rq);
+ struct rq *src_rq = rq;
+ int dst_cpu = rq->push_cpu;
+ struct rq *dst_rq = cpu_rq(dst_cpu);
+ struct task_struct *p = rq->migrate_task;
+ /*
+ * One last check to make sure nobody else is playing
+ * with the source rq.
+ */
+ if (src_rq->active_balance)
+ goto out;
+
+ if (src_rq->nr_running <= 1)
+ goto out;
+
+ if (task_rq(p) != src_rq)
+ goto out;
+ /*
+ * Not sure if this applies here but one can never
+ * be too cautious
+ */
+ BUG_ON(src_rq == dst_rq);
+
+ double_lock_balance(src_rq, dst_rq);
+
+ rcu_read_lock();
+ for_each_domain(dst_cpu, sd) {
+ if (cpumask_test_cpu(src_cpu, sched_domain_span(sd)))
+ break;
+ }
+
+ if (likely(sd)) {
+ struct lb_env env = {
+ .sd = sd,
+ .dst_cpu = dst_cpu,
+ .dst_rq = dst_rq,
+ .src_cpu = src_cpu,
+ .src_rq = src_rq,
+ .idle = CPU_IDLE,
+ };
+
+ schedstat_inc(sd, alb_count);
+
+ if (move_specific_task(&env, p))
+ schedstat_inc(sd, alb_pushed);
+ else
+ schedstat_inc(sd, alb_failed);
+ }
+
+ rcu_read_unlock();
+ double_unlock_balance(src_rq, dst_rq);
+out:
+ put_task_struct(p);
+}
+
+static DEFINE_SPINLOCK(hmp_force_migration);
+
+/*
+ * hmp_force_up_migration checks runqueues for tasks that need to
+ * be actively migrated to a faster cpu.
+ */
+static void hmp_force_up_migration(int this_cpu)
+{
+ int cpu, target_cpu;
+ struct sched_entity *curr, *orig;
+ struct rq *target;
+ unsigned long flags;
+ unsigned int force, got_target;
+ struct task_struct *p;
+
+ if (!spin_trylock(&hmp_force_migration))
+ return;
+ for_each_online_cpu(cpu) {
+ force = 0;
+ got_target = 0;
+ target = cpu_rq(cpu);
+ raw_spin_lock_irqsave(&target->lock, flags);
+ curr = target->cfs.curr;
+ if (!curr) {
+ raw_spin_unlock_irqrestore(&target->lock, flags);
+ continue;
+ }
+ if (!entity_is_task(curr)) {
+ struct cfs_rq *cfs_rq;
+
+ cfs_rq = group_cfs_rq(curr);
+ while (cfs_rq) {
+ curr = cfs_rq->curr;
+ cfs_rq = group_cfs_rq(curr);
+ }
+ }
+ orig = curr;
+ curr = hmp_get_heaviest_task(curr, 1);
+ p = task_of(curr);
+ if (hmp_up_migration(cpu, &target_cpu, curr)) {
+ if (!target->active_balance) {
+ get_task_struct(p);
+ target->push_cpu = target_cpu;
+ target->migrate_task = p;
+ got_target = 1;
+ trace_sched_hmp_migrate(p, target->push_cpu, HMP_MIGRATE_FORCE);
+ hmp_next_up_delay(&p->se, target->push_cpu);
+ }
+ }
+ if (!got_target && !target->active_balance) {
+ /*
+ * For now we just check the currently running task.
+ * Selecting the lightest task for offloading will
+ * require extensive book keeping.
+ */
+ curr = hmp_get_lightest_task(orig, 1);
+ p = task_of(curr);
+ target->push_cpu = hmp_offload_down(cpu, curr);
+ if (target->push_cpu < NR_CPUS) {
+ get_task_struct(p);
+ target->migrate_task = p;
+ got_target = 1;
+ trace_sched_hmp_migrate(p, target->push_cpu, HMP_MIGRATE_OFFLOAD);
+ hmp_next_down_delay(&p->se, target->push_cpu);
+ }
+ }
+ /*
+ * We have a target with no active_balance. If the task
+ * is not currently running move it, otherwise let the
+ * CPU stopper take care of it.
+ */
+ if (got_target && !target->active_balance) {
+ if (!task_running(target, p)) {
+ trace_sched_hmp_migrate_force_running(p, 0);
+ hmp_migrate_runnable_task(target);
+ } else {
+ target->active_balance = 1;
+ force = 1;
+ }
+ }
+
+ raw_spin_unlock_irqrestore(&target->lock, flags);
+
+ if (force)
+ stop_one_cpu_nowait(cpu_of(target),
+ hmp_active_task_migration_cpu_stop,
+ target, &target->active_balance_work);
+ }
+ spin_unlock(&hmp_force_migration);
+}
+/*
+ * hmp_idle_pull looks at little domain runqueues to see
+ * if a task should be pulled.
+ *
+ * Reuses hmp_force_migration spinlock.
+ *
+ */
+static unsigned int hmp_idle_pull(int this_cpu)
+{
+ int cpu;
+ struct sched_entity *curr, *orig;
+ struct hmp_domain *hmp_domain = NULL;
+ struct rq *target = NULL, *rq;
+ unsigned long flags, ratio = 0;
+ unsigned int force = 0;
+ struct task_struct *p = NULL;
+
+ if (!hmp_cpu_is_slowest(this_cpu))
+ hmp_domain = hmp_slower_domain(this_cpu);
+ if (!hmp_domain)
+ return 0;
+
+ if (!spin_trylock(&hmp_force_migration))
+ return 0;
+
+ /* first select a task */
+ for_each_cpu(cpu, &hmp_domain->cpus) {
+ rq = cpu_rq(cpu);
+ raw_spin_lock_irqsave(&rq->lock, flags);
+ curr = rq->cfs.curr;
+ if (!curr) {
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+ continue;
+ }
+ if (!entity_is_task(curr)) {
+ struct cfs_rq *cfs_rq;
+
+ cfs_rq = group_cfs_rq(curr);
+ while (cfs_rq) {
+ curr = cfs_rq->curr;
+ if (!entity_is_task(curr))
+ cfs_rq = group_cfs_rq(curr);
+ else
+ cfs_rq = NULL;
+ }
+ }
+ orig = curr;
+ curr = hmp_get_heaviest_task(curr, 1);
+ if (curr->avg.load_avg_ratio > hmp_up_threshold &&
+ curr->avg.load_avg_ratio > ratio) {
+ p = task_of(curr);
+ target = rq;
+ ratio = curr->avg.load_avg_ratio;
+ }
+ raw_spin_unlock_irqrestore(&rq->lock, flags);
+ }
+
+ if (!p)
+ goto done;
+
+ /* now we have a candidate */
+ raw_spin_lock_irqsave(&target->lock, flags);
+ if (!target->active_balance && task_rq(p) == target) {
+ get_task_struct(p);
+ target->push_cpu = this_cpu;
+ target->migrate_task = p;
+ trace_sched_hmp_migrate(p, target->push_cpu, HMP_MIGRATE_IDLE_PULL);
+ hmp_next_up_delay(&p->se, target->push_cpu);
+ /*
+ * if the task isn't running move it right away.
+ * Otherwise setup the active_balance mechanic and let
+ * the CPU stopper do its job.
+ */
+ if (!task_running(target, p)) {
+ trace_sched_hmp_migrate_idle_running(p, 0);
+ hmp_migrate_runnable_task(target);
+ } else {
+ target->active_balance = 1;
+ force = 1;
+ }
+ }
+ raw_spin_unlock_irqrestore(&target->lock, flags);
+
+ if (force) {
+ stop_one_cpu_nowait(cpu_of(target),
+ hmp_idle_pull_cpu_stop,
+ target, &target->active_balance_work);
+ }
+done:
+ spin_unlock(&hmp_force_migration);
+ return force;
+}
+#else
+static void hmp_force_up_migration(int this_cpu) { }
+#endif /* CONFIG_SCHED_HMP */
+
/*
* run_rebalance_domains is triggered when needed from the scheduler tick.
* Also triggered for nohz idle balancing (with nohz_balancing_kick set).
enum cpu_idle_type idle = this_rq->idle_balance ?
CPU_IDLE : CPU_NOT_IDLE;
+ hmp_force_up_migration(this_cpu);
+
rebalance_domains(this_cpu, idle);
/*
static void rq_online_fair(struct rq *rq)
{
+#ifdef CONFIG_SCHED_HMP
+ hmp_online_cpu(rq->cpu);
+#endif
update_sysctl();
}
static void rq_offline_fair(struct rq *rq)
{
+#ifdef CONFIG_SCHED_HMP
+ hmp_offline_cpu(rq->cpu);
+#endif
update_sysctl();
/* Ensure any throttled groups are reachable by pick_next_task */
zalloc_cpumask_var(&nohz.idle_cpus_mask, GFP_NOWAIT);
cpu_notifier(sched_ilb_notifier, 0);
#endif
+
+#ifdef CONFIG_SCHED_HMP
+ hmp_cpu_mask_setup();
+#endif
#endif /* SMP */
}
+
+#ifdef CONFIG_HMP_FREQUENCY_INVARIANT_SCALE
+static u32 cpufreq_calc_scale(u32 min, u32 max, u32 curr)
+{
+ u32 result = curr / max;
+ return result;
+}
+
+/* Called when the CPU Frequency is changed.
+ * Once for each CPU.
+ */
+static int cpufreq_callback(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ struct cpufreq_freqs *freq = data;
+ int cpu = freq->cpu;
+ struct cpufreq_extents *extents;
+
+ if (freq->flags & CPUFREQ_CONST_LOOPS)
+ return NOTIFY_OK;
+
+ if (val != CPUFREQ_POSTCHANGE)
+ return NOTIFY_OK;
+
+ /* if dynamic load scale is disabled, set the load scale to 1.0 */
+ if (!hmp_data.freqinvar_load_scale_enabled) {
+ freq_scale[cpu].curr_scale = 1024;
+ return NOTIFY_OK;
+ }
+
+ extents = &freq_scale[cpu];
+ if (extents->flags & SCHED_LOAD_FREQINVAR_SINGLEFREQ) {
+ /* If our governor was recognised as a single-freq governor,
+ * use 1.0
+ */
+ extents->curr_scale = 1024;
+ } else {
+ extents->curr_scale = cpufreq_calc_scale(extents->min,
+ extents->max, freq->new);
+ }
+
+ return NOTIFY_OK;
+}
+
+/* Called when the CPUFreq governor is changed.
+ * Only called for the CPUs which are actually changed by the
+ * userspace.
+ */
+static int cpufreq_policy_callback(struct notifier_block *nb,
+ unsigned long event, void *data)
+{
+ struct cpufreq_policy *policy = data;
+ struct cpufreq_extents *extents;
+ int cpu, singleFreq = 0;
+ static const char performance_governor[] = "performance";
+ static const char powersave_governor[] = "powersave";
+
+ if (event == CPUFREQ_START)
+ return 0;
+
+ if (event != CPUFREQ_INCOMPATIBLE)
+ return 0;
+
+ /* CPUFreq governors do not accurately report the range of
+ * CPU Frequencies they will choose from.
+ * We recognise performance and powersave governors as
+ * single-frequency only.
+ */
+ if (!strncmp(policy->governor->name, performance_governor,
+ strlen(performance_governor)) ||
+ !strncmp(policy->governor->name, powersave_governor,
+ strlen(powersave_governor)))
+ singleFreq = 1;
+
+ /* Make sure that all CPUs impacted by this policy are
+ * updated since we will only get a notification when the
+ * user explicitly changes the policy on a CPU.
+ */
+ for_each_cpu(cpu, policy->cpus) {
+ extents = &freq_scale[cpu];
+ extents->max = policy->max >> SCHED_FREQSCALE_SHIFT;
+ extents->min = policy->min >> SCHED_FREQSCALE_SHIFT;
+ if (!hmp_data.freqinvar_load_scale_enabled) {
+ extents->curr_scale = 1024;
+ } else if (singleFreq) {
+ extents->flags |= SCHED_LOAD_FREQINVAR_SINGLEFREQ;
+ extents->curr_scale = 1024;
+ } else {
+ extents->flags &= ~SCHED_LOAD_FREQINVAR_SINGLEFREQ;
+ extents->curr_scale = cpufreq_calc_scale(extents->min,
+ extents->max, policy->cur);
+ }
+ }
+
+ return 0;
+}
+
+static struct notifier_block cpufreq_notifier = {
+ .notifier_call = cpufreq_callback,
+};
+static struct notifier_block cpufreq_policy_notifier = {
+ .notifier_call = cpufreq_policy_callback,
+};
+
+static int __init register_sched_cpufreq_notifier(void)
+{
+ int ret = 0;
+
+ /* init safe defaults since there are no policies at registration */
+ for (ret = 0; ret < CONFIG_NR_CPUS; ret++) {
+ /* safe defaults */
+ freq_scale[ret].max = 1024;
+ freq_scale[ret].min = 1024;
+ freq_scale[ret].curr_scale = 1024;
+ }
+
+ pr_info("sched: registering cpufreq notifiers for scale-invariant loads\n");
+ ret = cpufreq_register_notifier(&cpufreq_policy_notifier,
+ CPUFREQ_POLICY_NOTIFIER);
+
+ if (ret != -EINVAL)
+ ret = cpufreq_register_notifier(&cpufreq_notifier,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ return ret;
+}
+
+core_initcall(register_sched_cpufreq_notifier);
+#endif /* CONFIG_HMP_FREQUENCY_INVARIANT_SCALE */
projects / firefly-linux-kernel-4.4.55.git / blobdiff