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LeafOS / LeafOS-Devices / android_kernel_samsung_gta4xl / 2f4f64cdfb599fa1369560865af3e52250416e15 / . / kernel / sched / rt.c
blob: 1258dc9a52bab09e1c6f135dc27af8e1ec7a9de5 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* Real-Time Scheduling Class (mapped to the SCHED_FIFO and SCHED_RR
* policies)
*/
#include "sched.h"
#include <linux/slab.h>
#include <linux/irq_work.h>
#include "tune.h"
#include <linux/ems.h>
#include "walt.h"
#include <trace/events/sched.h>
#ifdef CONFIG_SCHED_USE_FLUID_RT
struct frt_dom {
unsigned int coverage_ratio;
unsigned int coverage_thr;
unsigned int active_ratio;
unsigned int active_thr;
int coregroup;
struct cpumask cpus;
/* It is updated to relfect the system idle situation */
struct cpumask *activated_cpus;
struct list_head list;
struct frt_dom *next;
/* kobject for sysfs group */
struct kobject kobj;
};
struct cpumask activated_mask;
unsigned int frt_disable_cpufreq;
LIST_HEAD(frt_list);
DEFINE_RAW_SPINLOCK(frt_lock);
DEFINE_PER_CPU_SHARED_ALIGNED(struct frt_dom *, frt_rqs);
static struct kobject *frt_kobj;
#define RATIO_SCALE_SHIFT 10
#define cpu_util(rq) (rq->cfs.avg.util_avg + rq->rt.avg.util_avg)
#define ratio_scale(v, r) (((v) * (r) * 10) >> RATIO_SCALE_SHIFT)
static int frt_set_coverage_ratio(int cpu);
static int frt_set_active_ratio(int cpu);
struct frt_attr {
struct attribute attr;
ssize_t (*show)(struct kobject *, char *);
ssize_t (*store)(struct kobject *, const char *, size_t count);
};
#define frt_attr_rw(_name) \
static struct frt_attr _name##_attr = \
__ATTR(_name, 0644, show_##_name, store_##_name)
#define frt_show(_name) \
static ssize_t show_##_name(struct kobject *k, char *buf) \
{ \
struct frt_dom *dom = container_of(k, struct frt_dom, kobj); \
\
return sprintf(buf, "%u\n", (unsigned int)dom->_name); \
}
#define frt_store(_name, _type, _max) \
static ssize_t store_##_name(struct kobject *k, const char *buf, size_t count) \
{ \
unsigned int val; \
struct frt_dom *dom = container_of(k, struct frt_dom, kobj); \
\
if (!sscanf(buf, "%u", &val)) \
return -EINVAL; \
\
val = val > _max ? _max : val; \
dom->_name = (_type)val; \
frt_set_##_name(cpumask_first(&dom->cpus)); \
\
return count; \
}
static ssize_t show_coverage_ratio(struct kobject *k, char *buf)
{
struct frt_dom *dom = container_of(k, struct frt_dom, kobj);
return sprintf(buf, "%u (%u)\n", dom->coverage_ratio, dom->coverage_thr);
}
static ssize_t show_active_ratio(struct kobject *k, char *buf)
{
struct frt_dom *dom = container_of(k, struct frt_dom, kobj);
return sprintf(buf, "%u (%u)\n", dom->active_ratio, dom->active_thr);
}
frt_store(coverage_ratio, int, 100);
frt_attr_rw(coverage_ratio);
frt_store(active_ratio, int, 100);
frt_attr_rw(active_ratio);
static ssize_t show(struct kobject *kobj, struct attribute *at, char *buf)
{
struct frt_attr *frtattr = container_of(at, struct frt_attr, attr);
return frtattr->show(kobj, buf);
}
static ssize_t store(struct kobject *kobj, struct attribute *at,
const char *buf, size_t count)
{
struct frt_attr *frtattr = container_of(at, struct frt_attr, attr);
return frtattr->store(kobj, buf, count);
}
static const struct sysfs_ops frt_sysfs_ops = {
.show = show,
.store = store,
};
static struct attribute *dom_frt_attrs[] = {
&coverage_ratio_attr.attr,
&active_ratio_attr.attr,
NULL
};
static struct kobj_type ktype_frt = {
.sysfs_ops = &frt_sysfs_ops,
.default_attrs = dom_frt_attrs,
};
static ssize_t store_disable_cpufreq(struct kobject *kobj,
struct kobj_attribute *attr, const char *buf,
size_t count)
{
unsigned int val;
if (!sscanf(buf, "%u", &val))
return -EINVAL;
frt_disable_cpufreq = val;
return count;
}
static ssize_t show_disable_cpufreq(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%u\n", frt_disable_cpufreq);
}
static struct kobj_attribute disable_cpufreq_attr =
__ATTR(disable_cpufreq, 0644, show_disable_cpufreq, store_disable_cpufreq);
static struct attribute *frt_attrs[] = {
&disable_cpufreq_attr.attr,
NULL,
};
static const struct attribute_group frt_group = {
.attrs = frt_attrs,
};
static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu);
static inline int has_pushable_tasks(struct rq *rq);
#define MIN_RUNNABLE_THRESHOLD (500000)
static bool frt_short_runnable(struct task_struct *p)
{
return ktime_get_ns() - p->last_waked_ns < MIN_RUNNABLE_THRESHOLD;
}
static bool frt_sched_runnable(struct rq *rq)
{
return rq->rt.rt_queued > 0;
}
int frt_idle_pull_tasks(struct rq *dst_rq)
{
struct rq *src_rq;
struct task_struct *pulled_task;
int cpu, src_cpu = -1, dst_cpu = dst_rq->cpu, ret = 0;
if (frt_sched_runnable(dst_rq))
return 0;
for_each_possible_cpu(cpu) {
if (has_pushable_tasks(cpu_rq(cpu))) {
src_cpu = cpu;
break;
}
}
if (src_cpu == -1)
return 0;
if (src_cpu == dst_cpu)
return 0;
src_rq = cpu_rq(src_cpu);
double_lock_balance(dst_rq, src_rq);
if (frt_sched_runnable(dst_rq))
goto out;
pulled_task = pick_highest_pushable_task(src_rq, dst_cpu);
if (!pulled_task)
goto out;
if (frt_short_runnable(pulled_task))
goto out;
deactivate_task(src_rq, pulled_task, 0);
pulled_task->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(pulled_task, dst_cpu);
pulled_task->on_rq = TASK_ON_RQ_QUEUED;
activate_task(dst_rq, pulled_task, 0);
ret = 1;
out:
if (ret)
trace_sched_frt_idle_pull_tasks(pulled_task, src_cpu, dst_cpu);
double_unlock_balance(dst_rq, src_rq);
return ret;
}
static int frt_find_prefer_cpu(struct task_struct *task)
{
int cpu, allowed_cpu = 0;
unsigned int coverage_thr;
struct frt_dom *dom;
list_for_each_entry(dom, &frt_list, list) {
coverage_thr = per_cpu(frt_rqs, cpumask_first(&dom->cpus))->coverage_thr;
for_each_cpu_and(cpu, &task->cpus_allowed, &dom->cpus) {
allowed_cpu = cpu;
if (task->rt.avg.util_avg < coverage_thr)
return allowed_cpu;
}
}
return allowed_cpu;
}
static int frt_set_active_ratio(int cpu)
{
unsigned long capacity;
struct frt_dom *dom = per_cpu(frt_rqs, cpu);
if (!dom || !cpu_active(cpu))
return -1;
capacity = get_cpu_max_capacity(cpu) *
cpumask_weight(cpu_coregroup_mask(cpu));
dom->active_thr = ratio_scale(capacity, dom->active_ratio);
return 0;
}
static int frt_set_coverage_ratio(int cpu)
{
unsigned long capacity;
struct frt_dom *dom = per_cpu(frt_rqs, cpu);
if (!dom || !cpu_active(cpu))
return -1;
capacity = get_cpu_max_capacity(cpu);
dom->coverage_thr = ratio_scale(capacity, dom->coverage_ratio);
return 0;
}
static const struct cpumask *get_activated_cpus(void)
{
struct frt_dom *dom = per_cpu(frt_rqs, 0);
if (dom)
return dom->activated_cpus;
return cpu_active_mask;
}
static void update_activated_cpus(void)
{
struct frt_dom *dom, *prev_idle_dom = NULL;
struct cpumask mask;
unsigned long flags;
if (!raw_spin_trylock_irqsave(&frt_lock, flags))
return;
cpumask_setall(&mask);
list_for_each_entry_reverse(dom, &frt_list, list) {
unsigned long dom_util_sum = 0;
unsigned long dom_active_thr = 0;
unsigned long capacity;
struct cpumask active_cpus;
int first_cpu, cpu;
cpumask_and(&active_cpus, &dom->cpus, cpu_active_mask);
first_cpu = cpumask_first(&active_cpus);
/* all cpus of domain is offed */
if (first_cpu == NR_CPUS)
continue;
for_each_cpu(cpu, &active_cpus) {
struct rq *rq = cpu_rq(cpu);
dom_util_sum += cpu_util(rq);
}
capacity = get_cpu_max_capacity(first_cpu) * cpumask_weight(&active_cpus);
dom_active_thr = ratio_scale(capacity, dom->active_ratio);
/* domain is idle */
if (dom_util_sum < dom_active_thr) {
/* if prev domain is also idle, clear prev domain cpus */
if (prev_idle_dom)
cpumask_andnot(&mask, &mask, &prev_idle_dom->cpus);
prev_idle_dom = dom;
}
trace_sched_fluid_activated_cpus(first_cpu, dom_util_sum,
dom_active_thr, *(unsigned int *)cpumask_bits(&mask));
/* this is first domain, do update activated_cpus */
if (first_cpu == 0)
cpumask_copy(dom->activated_cpus, &mask);
}
raw_spin_unlock_irqrestore(&frt_lock, flags);
}
static int __init frt_sysfs_init(void)
{
struct frt_dom *dom;
if (list_empty(&frt_list))
return 0;
frt_kobj = kobject_create_and_add("frt", ems_kobj);
if (!frt_kobj)
goto out;
/* Add frt sysfs node for each coregroup */
list_for_each_entry(dom, &frt_list, list) {
if (kobject_init_and_add(&dom->kobj, &ktype_frt,
frt_kobj, "coregroup%d", dom->coregroup))
goto out;
}
/* add frt syfs for global control */
if (sysfs_create_group(frt_kobj, &frt_group))
goto out;
return 0;
out:
pr_err("FRT(%s): failed to create sysfs node\n", __func__);
return -EINVAL;
}
static void frt_parse_dt(struct device_node *dn, struct frt_dom *dom, int cnt)
{
struct device_node *frt, *coregroup;
char name[15];
frt = of_get_child_by_name(dn, "frt");
if (!frt)
goto disable;
snprintf(name, sizeof(name), "coregroup%d", cnt);
coregroup = of_get_child_by_name(frt, name);
if (!coregroup)
goto disable;
dom->coregroup = cnt;
of_property_read_u32(coregroup, "coverage-ratio", &dom->coverage_ratio);
if (!dom->coverage_ratio)
dom->coverage_ratio = 100;
of_property_read_u32(coregroup, "active-ratio", &dom->active_ratio);
if (!dom->active_ratio)
dom->active_thr = 0;
return;
disable:
dom->coregroup = cnt;
dom->coverage_ratio = 100;
dom->active_thr = 0;
pr_err("FRT(%s): failed to parse frt node\n", __func__);
}
static int __init init_frt(void)
{
struct frt_dom *dom, *prev = NULL, *head = NULL;
struct device_node *dn;
int cpu, tcpu, cnt = 0;
dn = of_find_node_by_path("/cpus/ems");
if (!dn)
return 0;
INIT_LIST_HEAD(&frt_list);
cpumask_setall(&activated_mask);
for_each_possible_cpu(cpu) {
if (cpu != cpumask_first(cpu_coregroup_mask(cpu)))
continue;
dom = kzalloc(sizeof(struct frt_dom), GFP_KERNEL);
if (!dom) {
pr_err("FRT(%s): failed to allocate dom\n", __func__);
goto put_node;
}
if (head == NULL)
head = dom;
dom->activated_cpus = &activated_mask;
cpumask_copy(&dom->cpus, cpu_coregroup_mask(cpu));
frt_parse_dt(dn, dom, cnt++);
dom->next = head;
if (prev)
prev->next = dom;
prev = dom;
for_each_cpu(tcpu, &dom->cpus)
per_cpu(frt_rqs, tcpu) = dom;
frt_set_coverage_ratio(cpu);
frt_set_active_ratio(cpu);
list_add_tail(&dom->list, &frt_list);
}
frt_sysfs_init();
put_node:
of_node_put(dn);
return 0;
} late_initcall(init_frt);
#else
static inline void update_activated_cpus(void) { };
#endif
int sched_rr_timeslice = RR_TIMESLICE;
int sysctl_sched_rr_timeslice = (MSEC_PER_SEC * RR_TIMESLICE) / HZ;
void update_rt_load_avg(u64 now, struct sched_rt_entity *rt_se);
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun);
struct rt_bandwidth def_rt_bandwidth;
static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer)
{
struct rt_bandwidth *rt_b =
container_of(timer, struct rt_bandwidth, rt_period_timer);
int idle = 0;
int overrun;
raw_spin_lock(&rt_b->rt_runtime_lock);
for (;;) {
overrun = hrtimer_forward_now(timer, rt_b->rt_period);
if (!overrun)
break;
raw_spin_unlock(&rt_b->rt_runtime_lock);
idle = do_sched_rt_period_timer(rt_b, overrun);
raw_spin_lock(&rt_b->rt_runtime_lock);
}
if (idle)
rt_b->rt_period_active = 0;
raw_spin_unlock(&rt_b->rt_runtime_lock);
return idle ? HRTIMER_NORESTART : HRTIMER_RESTART;
}
void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime)
{
rt_b->rt_period = ns_to_ktime(period);
rt_b->rt_runtime = runtime;
raw_spin_lock_init(&rt_b->rt_runtime_lock);
hrtimer_init(&rt_b->rt_period_timer,
CLOCK_MONOTONIC, HRTIMER_MODE_REL);
rt_b->rt_period_timer.function = sched_rt_period_timer;
}
static inline void do_start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
raw_spin_lock(&rt_b->rt_runtime_lock);
if (!rt_b->rt_period_active) {
rt_b->rt_period_active = 1;
/*
* SCHED_DEADLINE updates the bandwidth, as a run away
* RT task with a DL task could hog a CPU. But DL does
* not reset the period. If a deadline task was running
* without an RT task running, it can cause RT tasks to
* throttle when they start up. Kick the timer right away
* to update the period.
*/
hrtimer_forward_now(&rt_b->rt_period_timer, ns_to_ktime(0));
hrtimer_start_expires(&rt_b->rt_period_timer, HRTIMER_MODE_ABS_PINNED);
}
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
static void start_rt_bandwidth(struct rt_bandwidth *rt_b)
{
if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
return;
do_start_rt_bandwidth(rt_b);
}
void init_rt_rq(struct rt_rq *rt_rq)
{
struct rt_prio_array *array;
int i;
array = &rt_rq->active;
for (i = 0; i < MAX_RT_PRIO; i++) {
INIT_LIST_HEAD(array->queue + i);
__clear_bit(i, array->bitmap);
}
/* delimiter for bitsearch: */
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP
rt_rq->highest_prio.curr = MAX_RT_PRIO;
rt_rq->highest_prio.next = MAX_RT_PRIO;
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
plist_head_init(&rt_rq->pushable_tasks);
atomic_long_set(&rt_rq->removed_util_avg, 0);
atomic_long_set(&rt_rq->removed_load_avg, 0);
#endif /* CONFIG_SMP */
/* We start is dequeued state, because no RT tasks are queued */
rt_rq->rt_queued = 0;
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
rt_rq->rt_runtime = 0;
raw_spin_lock_init(&rt_rq->rt_runtime_lock);
}
#ifdef CONFIG_RT_GROUP_SCHED
static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b)
{
hrtimer_cancel(&rt_b->rt_period_timer);
}
#define rt_entity_is_task(rt_se) (!(rt_se)->my_q)
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_SCHED_DEBUG
WARN_ON_ONCE(!rt_entity_is_task(rt_se));
#endif
return container_of(rt_se, struct task_struct, rt);
}
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return rt_rq->rq;
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
return rt_se->rt_rq;
}
static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_se->rt_rq;
return rt_rq->rq;
}
void free_rt_sched_group(struct task_group *tg)
{
int i;
if (tg->rt_se)
destroy_rt_bandwidth(&tg->rt_bandwidth);
for_each_possible_cpu(i) {
if (tg->rt_rq)
kfree(tg->rt_rq[i]);
if (tg->rt_se)
kfree(tg->rt_se[i]);
}
kfree(tg->rt_rq);
kfree(tg->rt_se);
}
void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq,
struct sched_rt_entity *rt_se, int cpu,
struct sched_rt_entity *parent)
{
struct rq *rq = cpu_rq(cpu);
rt_rq->highest_prio.curr = MAX_RT_PRIO;
rt_rq->rt_nr_boosted = 0;
rt_rq->rq = rq;
rt_rq->tg = tg;
tg->rt_rq[cpu] = rt_rq;
tg->rt_se[cpu] = rt_se;
if (!rt_se)
return;
if (!parent)
rt_se->rt_rq = &rq->rt;
else
rt_se->rt_rq = parent->my_q;
rt_se->my_q = rt_rq;
rt_se->parent = parent;
INIT_LIST_HEAD(&rt_se->run_list);
}
int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
{
struct rt_rq *rt_rq;
struct sched_rt_entity *rt_se;
int i;
tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL);
if (!tg->rt_rq)
goto err;
tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL);
if (!tg->rt_se)
goto err;
init_rt_bandwidth(&tg->rt_bandwidth,
ktime_to_ns(def_rt_bandwidth.rt_period), 0);
for_each_possible_cpu(i) {
rt_rq = kzalloc_node(sizeof(struct rt_rq),
GFP_KERNEL, cpu_to_node(i));
if (!rt_rq)
goto err;
rt_se = kzalloc_node(sizeof(struct sched_rt_entity),
GFP_KERNEL, cpu_to_node(i));
if (!rt_se)
goto err_free_rq;
init_rt_rq(rt_rq);
rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime;
init_tg_rt_entry(tg, rt_rq, rt_se, i, parent->rt_se[i]);
init_rt_entity_runnable_average(rt_se);
}
return 1;
err_free_rq:
kfree(rt_rq);
err:
return 0;
}
#else /* CONFIG_RT_GROUP_SCHED */
#define rt_entity_is_task(rt_se) (1)
static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
{
return container_of(rt_se, struct task_struct, rt);
}
static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
{
return container_of(rt_rq, struct rq, rt);
}
static inline struct rq *rq_of_rt_se(struct sched_rt_entity *rt_se)
{
struct task_struct *p = rt_task_of(rt_se);
return task_rq(p);
}
static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
{
struct rq *rq = rq_of_rt_se(rt_se);
return &rq->rt;
}
void free_rt_sched_group(struct task_group *tg) { }
int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent)
{
return 1;
}
#endif /* CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_SMP
#include "sched-pelt.h"
#define entity_is_task(se) (!se->my_q)
extern u64 decay_load(u64 val, u64 n);
static u32 __accumulate_pelt_segments_rt(u64 periods, u32 d1, u32 d3)
{
u32 c1, c2, c3 = d3;
c1 = decay_load((u64)d1, periods);
c2 = LOAD_AVG_MAX - decay_load(LOAD_AVG_MAX, periods) - 1024;
return c1 + c2 + c3;
}
#define cap_scale(v, s) ((v)*(s) >> SCHED_CAPACITY_SHIFT)
static __always_inline u32
accumulate_sum_rt(u64 delta, int cpu, struct sched_avg *sa,
unsigned long weight, int running)
{
unsigned long scale_freq, scale_cpu;
u32 contrib = (u32)delta;
u64 periods;
scale_freq = arch_scale_freq_capacity(NULL, cpu);
scale_cpu = arch_scale_cpu_capacity(NULL, cpu);
delta += sa->period_contrib;
periods = delta / 1024;
if (periods) {
sa->load_sum = decay_load(sa->load_sum, periods);
sa->util_sum = decay_load((u64)(sa->util_sum), periods);
delta %= 1024;
contrib = __accumulate_pelt_segments_rt(periods,
1024 - sa->period_contrib, delta);
}
sa->period_contrib = delta;
contrib = cap_scale(contrib, scale_freq);
if (weight) {
sa->load_sum += weight * contrib;
}
if (running)
sa->util_sum += (u32)(contrib * scale_cpu);
return periods;
}
/*
* We can represent the historical contribution to runnable average as the
* coefficients of a geometric series, exactly like fair task load.
* refer the ___update_load_avg @ fair sched class
*/
static __always_inline int
__update_load_avg(u64 now, int cpu, struct sched_avg *sa,
unsigned long weight, int running, struct rt_rq *rt_rq)
{
u64 delta;
delta = now - sa->last_update_time;
if ((s64)delta < 0) {
sa->last_update_time = now;
return 0;
}
delta >>= 10;
if (!delta)
return 0;
sa->last_update_time += delta << 10;
if (!weight)
running = 0;
if (!accumulate_sum_rt(delta, cpu, sa, weight, running))
return 0;
sa->load_avg = div_u64(sa->load_sum, LOAD_AVG_MAX - 1024 + sa->period_contrib);
sa->util_avg = sa->util_sum / (LOAD_AVG_MAX - 1024 + sa->period_contrib);
return 1;
}
static void pull_rt_task(struct rq *this_rq);
static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
return rq->rt.highest_prio.curr > prev->prio;
}
static inline int rt_overloaded(struct rq *rq)
{
return atomic_read(&rq->rd->rto_count);
}
static inline void rt_set_overload(struct rq *rq)
{
if (!rq->online)
return;
cpumask_set_cpu(rq->cpu, rq->rd->rto_mask);
/*
* Make sure the mask is visible before we set
* the overload count. That is checked to determine
* if we should look at the mask. It would be a shame
* if we looked at the mask, but the mask was not
* updated yet.
*
* Matched by the barrier in pull_rt_task().
*/
smp_wmb();
atomic_inc(&rq->rd->rto_count);
}
static inline void rt_clear_overload(struct rq *rq)
{
if (!rq->online)
return;
/* the order here really doesn't matter */
atomic_dec(&rq->rd->rto_count);
cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
}
static void update_rt_migration(struct rt_rq *rt_rq)
{
if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) {
if (!rt_rq->overloaded) {
rt_set_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 1;
}
} else if (rt_rq->overloaded) {
rt_clear_overload(rq_of_rt_rq(rt_rq));
rt_rq->overloaded = 0;
}
}
static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
struct task_struct *p;
if (!rt_entity_is_task(rt_se))
return;
p = rt_task_of(rt_se);
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total++;
if (p->nr_cpus_allowed > 1)
rt_rq->rt_nr_migratory++;
update_rt_migration(rt_rq);
}
static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
struct task_struct *p;
if (!rt_entity_is_task(rt_se))
return;
p = rt_task_of(rt_se);
rt_rq = &rq_of_rt_rq(rt_rq)->rt;
rt_rq->rt_nr_total--;
if (p->nr_cpus_allowed > 1)
rt_rq->rt_nr_migratory--;
update_rt_migration(rt_rq);
}
static inline int has_pushable_tasks(struct rq *rq)
{
return !plist_head_empty(&rq->rt.pushable_tasks);
}
static DEFINE_PER_CPU(struct callback_head, rt_push_head);
static DEFINE_PER_CPU(struct callback_head, rt_pull_head);
static void push_rt_tasks(struct rq *);
static void pull_rt_task(struct rq *);
static inline void queue_push_tasks(struct rq *rq)
{
if (!has_pushable_tasks(rq))
return;
queue_balance_callback(rq, &per_cpu(rt_push_head, rq->cpu), push_rt_tasks);
}
static inline void queue_pull_task(struct rq *rq)
{
queue_balance_callback(rq, &per_cpu(rt_pull_head, rq->cpu), pull_rt_task);
}
static void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
plist_node_init(&p->pushable_tasks, p->prio);
plist_add(&p->pushable_tasks, &rq->rt.pushable_tasks);
/* Update the highest prio pushable task */
if (p->prio < rq->rt.highest_prio.next)
rq->rt.highest_prio.next = p->prio;
}
static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
/* Update the new highest prio pushable task */
if (has_pushable_tasks(rq)) {
p = plist_first_entry(&rq->rt.pushable_tasks,
struct task_struct, pushable_tasks);
rq->rt.highest_prio.next = p->prio;
} else
rq->rt.highest_prio.next = MAX_RT_PRIO;
}
#else
static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
}
static inline void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
{
}
static inline
void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
static inline
void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
}
static inline bool need_pull_rt_task(struct rq *rq, struct task_struct *prev)
{
return false;
}
static inline void pull_rt_task(struct rq *this_rq)
{
}
static inline void queue_push_tasks(struct rq *rq)
{
}
#endif /* CONFIG_SMP */
static void enqueue_top_rt_rq(struct rt_rq *rt_rq);
static void dequeue_top_rt_rq(struct rt_rq *rt_rq);
static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
return rt_se->on_rq;
}
#ifdef CONFIG_RT_GROUP_SCHED
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
if (!rt_rq->tg)
return RUNTIME_INF;
return rt_rq->rt_runtime;
}
static inline u64 sched_rt_period(struct rt_rq *rt_rq)
{
return ktime_to_ns(rt_rq->tg->rt_bandwidth.rt_period);
}
typedef struct task_group *rt_rq_iter_t;
static inline struct task_group *next_task_group(struct task_group *tg)
{
do {
tg = list_entry_rcu(tg->list.next,
typeof(struct task_group), list);
} while (&tg->list != &task_groups && task_group_is_autogroup(tg));
if (&tg->list == &task_groups)
tg = NULL;
return tg;
}
#define for_each_rt_rq(rt_rq, iter, rq) \
for (iter = container_of(&task_groups, typeof(*iter), list); \
(iter = next_task_group(iter)) && \
(rt_rq = iter->rt_rq[cpu_of(rq)]);)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return rt_se->my_q;
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags);
static void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct task_struct *curr = rq_of_rt_rq(rt_rq)->curr;
struct rq *rq = rq_of_rt_rq(rt_rq);
struct sched_rt_entity *rt_se;
int cpu = cpu_of(rq);
rt_se = rt_rq->tg->rt_se[cpu];
if (rt_rq->rt_nr_running) {
if (!rt_se)
enqueue_top_rt_rq(rt_rq);
else if (!on_rt_rq(rt_se))
enqueue_rt_entity(rt_se, 0);
if (rt_rq->highest_prio.curr < curr->prio)
resched_curr(rq);
}
}
static void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
struct sched_rt_entity *rt_se;
int cpu = cpu_of(rq_of_rt_rq(rt_rq));
rt_se = rt_rq->tg->rt_se[cpu];
if (!rt_se)
dequeue_top_rt_rq(rt_rq);
else if (on_rt_rq(rt_se))
dequeue_rt_entity(rt_se, 0);
}
static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
return rt_rq->rt_throttled && !rt_rq->rt_nr_boosted;
}
static int rt_se_boosted(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = group_rt_rq(rt_se);
struct task_struct *p;
if (rt_rq)
return !!rt_rq->rt_nr_boosted;
p = rt_task_of(rt_se);
return p->prio != p->normal_prio;
}
#ifdef CONFIG_SMP
static inline const struct cpumask *sched_rt_period_mask(void)
{
return this_rq()->rd->span;
}
#else
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
#endif
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return container_of(rt_b, struct task_group, rt_bandwidth)->rt_rq[cpu];
}
static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
return &rt_rq->tg->rt_bandwidth;
}
#else /* !CONFIG_RT_GROUP_SCHED */
static inline u64 sched_rt_runtime(struct rt_rq *rt_rq)
{
return rt_rq->rt_runtime;
}
static inline u64 sched_rt_period(struct rt_rq *rt_rq)
{
return ktime_to_ns(def_rt_bandwidth.rt_period);
}
typedef struct rt_rq *rt_rq_iter_t;
#define for_each_rt_rq(rt_rq, iter, rq) \
for ((void) iter, rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
static inline struct rt_rq *group_rt_rq(struct sched_rt_entity *rt_se)
{
return NULL;
}
static inline void sched_rt_rq_enqueue(struct rt_rq *rt_rq)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
if (!rt_rq->rt_nr_running)
return;
enqueue_top_rt_rq(rt_rq);
resched_curr(rq);
}
static inline void sched_rt_rq_dequeue(struct rt_rq *rt_rq)
{
dequeue_top_rt_rq(rt_rq);
}
static inline int rt_rq_throttled(struct rt_rq *rt_rq)
{
return rt_rq->rt_throttled;
}
static inline const struct cpumask *sched_rt_period_mask(void)
{
return cpu_online_mask;
}
static inline
struct rt_rq *sched_rt_period_rt_rq(struct rt_bandwidth *rt_b, int cpu)
{
return &cpu_rq(cpu)->rt;
}
static inline struct rt_bandwidth *sched_rt_bandwidth(struct rt_rq *rt_rq)
{
return &def_rt_bandwidth;
}
#endif /* CONFIG_RT_GROUP_SCHED */
bool sched_rt_bandwidth_account(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
return (hrtimer_active(&rt_b->rt_period_timer) ||
rt_rq->rt_time < rt_b->rt_runtime);
}
#ifdef CONFIG_SMP
/*
* We ran out of runtime, see if we can borrow some from our neighbours.
*/
static void do_balance_runtime(struct rt_rq *rt_rq)
{
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
struct root_domain *rd = rq_of_rt_rq(rt_rq)->rd;
int i, weight;
u64 rt_period;
weight = cpumask_weight(rd->span);
raw_spin_lock(&rt_b->rt_runtime_lock);
rt_period = ktime_to_ns(rt_b->rt_period);
for_each_cpu(i, rd->span) {
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
if (iter == rt_rq)
continue;
raw_spin_lock(&iter->rt_runtime_lock);
/*
* Either all rqs have inf runtime and there's nothing to steal
* or __disable_runtime() below sets a specific rq to inf to
* indicate its been disabled and disalow stealing.
*/
if (iter->rt_runtime == RUNTIME_INF)
goto next;
/*
* From runqueues with spare time, take 1/n part of their
* spare time, but no more than our period.
*/
diff = iter->rt_runtime - iter->rt_time;
if (diff > 0) {
diff = div_u64((u64)diff, weight);
if (rt_rq->rt_runtime + diff > rt_period)
diff = rt_period - rt_rq->rt_runtime;
iter->rt_runtime -= diff;
rt_rq->rt_runtime += diff;
if (rt_rq->rt_runtime == rt_period) {
raw_spin_unlock(&iter->rt_runtime_lock);
break;
}
}
next:
raw_spin_unlock(&iter->rt_runtime_lock);
}
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
/*
* Ensure this RQ takes back all the runtime it lend to its neighbours.
*/
static void __disable_runtime(struct rq *rq)
{
struct root_domain *rd = rq->rd;
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
if (unlikely(!scheduler_running))
return;
for_each_rt_rq(rt_rq, iter, rq) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
s64 want;
int i;
raw_spin_lock(&rt_b->rt_runtime_lock);
raw_spin_lock(&rt_rq->rt_runtime_lock);
/*
* Either we're all inf and nobody needs to borrow, or we're
* already disabled and thus have nothing to do, or we have
* exactly the right amount of runtime to take out.
*/
if (rt_rq->rt_runtime == RUNTIME_INF ||
rt_rq->rt_runtime == rt_b->rt_runtime)
goto balanced;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
/*
* Calculate the difference between what we started out with
* and what we current have, that's the amount of runtime
* we lend and now have to reclaim.
*/
want = rt_b->rt_runtime - rt_rq->rt_runtime;
/*
* Greedy reclaim, take back as much as we can.
*/
for_each_cpu(i, rd->span) {
struct rt_rq *iter = sched_rt_period_rt_rq(rt_b, i);
s64 diff;
/*
* Can't reclaim from ourselves or disabled runqueues.
*/
if (iter == rt_rq || iter->rt_runtime == RUNTIME_INF)
continue;
raw_spin_lock(&iter->rt_runtime_lock);
if (want > 0) {
diff = min_t(s64, iter->rt_runtime, want);
iter->rt_runtime -= diff;
want -= diff;
} else {
iter->rt_runtime -= want;
want -= want;
}
raw_spin_unlock(&iter->rt_runtime_lock);
if (!want)
break;
}
raw_spin_lock(&rt_rq->rt_runtime_lock);
/*
* We cannot be left wanting - that would mean some runtime
* leaked out of the system.
*/
BUG_ON(want);
balanced:
/*
* Disable all the borrow logic by pretending we have inf
* runtime - in which case borrowing doesn't make sense.
*/
rt_rq->rt_runtime = RUNTIME_INF;
rt_rq->rt_throttled = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
/* Make rt_rq available for pick_next_task() */
sched_rt_rq_enqueue(rt_rq);
}
}
static void __enable_runtime(struct rq *rq)
{
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
if (unlikely(!scheduler_running))
return;
/*
* Reset each runqueue's bandwidth settings
*/
for_each_rt_rq(rt_rq, iter, rq) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
raw_spin_lock(&rt_b->rt_runtime_lock);
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_runtime = rt_b->rt_runtime;
rt_rq->rt_time = 0;
rt_rq->rt_throttled = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
raw_spin_unlock(&rt_b->rt_runtime_lock);
}
}
static void balance_runtime(struct rt_rq *rt_rq)
{
if (!sched_feat(RT_RUNTIME_SHARE))
return;
if (rt_rq->rt_time > rt_rq->rt_runtime) {
raw_spin_unlock(&rt_rq->rt_runtime_lock);
do_balance_runtime(rt_rq);
raw_spin_lock(&rt_rq->rt_runtime_lock);
}
}
#else /* !CONFIG_SMP */
static inline void balance_runtime(struct rt_rq *rt_rq) {}
#endif /* CONFIG_SMP */
static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun)
{
int i, idle = 1, throttled = 0;
const struct cpumask *span;
span = sched_rt_period_mask();
#ifdef CONFIG_RT_GROUP_SCHED
/*
* FIXME: isolated CPUs should really leave the root task group,
* whether they are isolcpus or were isolated via cpusets, lest
* the timer run on a CPU which does not service all runqueues,
* potentially leaving other CPUs indefinitely throttled. If
* isolation is really required, the user will turn the throttle
* off to kill the perturbations it causes anyway. Meanwhile,
* this maintains functionality for boot and/or troubleshooting.
*/
if (rt_b == &root_task_group.rt_bandwidth)
span = cpu_online_mask;
#endif
for_each_cpu(i, span) {
int enqueue = 0;
struct rt_rq *rt_rq = sched_rt_period_rt_rq(rt_b, i);
struct rq *rq = rq_of_rt_rq(rt_rq);
int skip;
/*
* When span == cpu_online_mask, taking each rq->lock
* can be time-consuming. Try to avoid it when possible.
*/
raw_spin_lock(&rt_rq->rt_runtime_lock);
if (!sched_feat(RT_RUNTIME_SHARE) && rt_rq->rt_runtime != RUNTIME_INF)
rt_rq->rt_runtime = rt_b->rt_runtime;
skip = !rt_rq->rt_time && !rt_rq->rt_nr_running;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
if (skip)
continue;
raw_spin_lock(&rq->lock);
update_rq_clock(rq);
if (rt_rq->rt_time) {
u64 runtime;
raw_spin_lock(&rt_rq->rt_runtime_lock);
if (rt_rq->rt_throttled)
balance_runtime(rt_rq);
runtime = rt_rq->rt_runtime;
rt_rq->rt_time -= min(rt_rq->rt_time, overrun*runtime);
if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) {
rt_rq->rt_throttled = 0;
enqueue = 1;
/*
* When we're idle and a woken (rt) task is
* throttled check_preempt_curr() will set
* skip_update and the time between the wakeup
* and this unthrottle will get accounted as
* 'runtime'.
*/
if (rt_rq->rt_nr_running && rq->curr == rq->idle)
rq_clock_skip_update(rq, false);
}
if (rt_rq->rt_time || rt_rq->rt_nr_running)
idle = 0;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
} else if (rt_rq->rt_nr_running) {
idle = 0;
if (!rt_rq_throttled(rt_rq))
enqueue = 1;
}
if (rt_rq->rt_throttled)
throttled = 1;
if (enqueue)
sched_rt_rq_enqueue(rt_rq);
raw_spin_unlock(&rq->lock);
}
if (!throttled && (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF))
return 1;
return idle;
}
static inline int rt_se_prio(struct sched_rt_entity *rt_se)
{
#ifdef CONFIG_RT_GROUP_SCHED
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
}
static int sched_rt_runtime_exceeded(struct rt_rq *rt_rq)
{
u64 runtime = sched_rt_runtime(rt_rq);
if (rt_rq->rt_throttled)
return rt_rq_throttled(rt_rq);
if (runtime >= sched_rt_period(rt_rq))
return 0;
balance_runtime(rt_rq);
runtime = sched_rt_runtime(rt_rq);
if (runtime == RUNTIME_INF)
return 0;
if (rt_rq->rt_time > runtime) {
struct rt_bandwidth *rt_b = sched_rt_bandwidth(rt_rq);
/*
* Don't actually throttle groups that have no runtime assigned
* but accrue some time due to boosting.
*/
if (likely(rt_b->rt_runtime)) {
rt_rq->rt_throttled = 1;
printk_deferred_once("sched: RT throttling activated\n");
} else {
/*
* In case we did anyway, make it go away,
* replenishment is a joke, since it will replenish us
* with exactly 0 ns.
*/
rt_rq->rt_time = 0;
}
if (rt_rq_throttled(rt_rq)) {
sched_rt_rq_dequeue(rt_rq);
return 1;
}
}
return 0;
}
/*
* Update the current task's runtime statistics. Skip current tasks that
* are not in our scheduling class.
*/
static void update_curr_rt(struct rq *rq)
{
struct task_struct *curr = rq->curr;
struct sched_rt_entity *rt_se = &curr->rt;
u64 delta_exec;
if (curr->sched_class != &rt_sched_class)
return;
delta_exec = rq_clock_task(rq) - curr->se.exec_start;
if (unlikely((s64)delta_exec <= 0))
return;
/* Kick cpufreq (see the comment in kernel/sched/sched.h). */
cpufreq_update_util(rq, SCHED_CPUFREQ_RT);
schedstat_set(curr->se.statistics.exec_max,
max(curr->se.statistics.exec_max, delta_exec));
curr->se.sum_exec_runtime += delta_exec;
account_group_exec_runtime(curr, delta_exec);
curr->se.exec_start = rq_clock_task(rq);
cpuacct_charge(curr, delta_exec);
sched_rt_avg_update(rq, delta_exec);
if (!rt_bandwidth_enabled())
return;
for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
int exceeded;
if (sched_rt_runtime(rt_rq) != RUNTIME_INF) {
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_time += delta_exec;
exceeded = sched_rt_runtime_exceeded(rt_rq);
if (exceeded)
resched_curr(rq);
raw_spin_unlock(&rt_rq->rt_runtime_lock);
if (exceeded)
do_start_rt_bandwidth(sched_rt_bandwidth(rt_rq));
}
}
}
static void
dequeue_top_rt_rq(struct rt_rq *rt_rq)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
BUG_ON(&rq->rt != rt_rq);
if (!rt_rq->rt_queued)
return;
BUG_ON(!rq->nr_running);
sub_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 0;
}
static void
enqueue_top_rt_rq(struct rt_rq *rt_rq)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
BUG_ON(&rq->rt != rt_rq);
if (rt_rq->rt_queued)
return;
if (rt_rq_throttled(rt_rq) || !rt_rq->rt_nr_running)
return;
add_nr_running(rq, rt_rq->rt_nr_running);
rt_rq->rt_queued = 1;
}
#if defined CONFIG_SMP
static void
inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Change rq's cpupri only if rt_rq is the top queue.
*/
if (&rq->rt != rt_rq)
return;
#endif
if (rq->online && prio < prev_prio)
cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
}
static void
dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio)
{
struct rq *rq = rq_of_rt_rq(rt_rq);
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Change rq's cpupri only if rt_rq is the top queue.
*/
if (&rq->rt != rt_rq)
return;
#endif
if (rq->online && rt_rq->highest_prio.curr != prev_prio)
cpupri_set(&rq->rd->cpupri, rq->cpu, rt_rq->highest_prio.curr);
}
#else /* CONFIG_SMP */
static inline
void inc_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
static inline
void dec_rt_prio_smp(struct rt_rq *rt_rq, int prio, int prev_prio) {}
#endif /* CONFIG_SMP */
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
static void
inc_rt_prio(struct rt_rq *rt_rq, int prio)
{
int prev_prio = rt_rq->highest_prio.curr;
if (prio < prev_prio)
rt_rq->highest_prio.curr = prio;
inc_rt_prio_smp(rt_rq, prio, prev_prio);
}
static void
dec_rt_prio(struct rt_rq *rt_rq, int prio)
{
int prev_prio = rt_rq->highest_prio.curr;
if (rt_rq->rt_nr_running) {
WARN_ON(prio < prev_prio);
/*
* This may have been our highest task, and therefore
* we may have some recomputation to do
*/
if (prio == prev_prio) {
struct rt_prio_array *array = &rt_rq->active;
rt_rq->highest_prio.curr =
sched_find_first_bit(array->bitmap);
}
} else
rt_rq->highest_prio.curr = MAX_RT_PRIO;
dec_rt_prio_smp(rt_rq, prio, prev_prio);
}
#else
static inline void inc_rt_prio(struct rt_rq *rt_rq, int prio) {}
static inline void dec_rt_prio(struct rt_rq *rt_rq, int prio) {}
#endif /* CONFIG_SMP || CONFIG_RT_GROUP_SCHED */
#ifdef CONFIG_RT_GROUP_SCHED
static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted++;
if (rt_rq->tg)
start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
}
static void
dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
if (rt_se_boosted(rt_se))
rt_rq->rt_nr_boosted--;
WARN_ON(!rt_rq->rt_nr_running && rt_rq->rt_nr_boosted);
}
#else /* CONFIG_RT_GROUP_SCHED */
static void
inc_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
start_rt_bandwidth(&def_rt_bandwidth);
}
static inline
void dec_rt_group(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) {}
#endif /* CONFIG_RT_GROUP_SCHED */
static inline
unsigned int rt_se_nr_running(struct sched_rt_entity *rt_se)
{
struct rt_rq *group_rq = group_rt_rq(rt_se);
if (group_rq)
return group_rq->rt_nr_running;
else
return 1;
}
static inline
unsigned int rt_se_rr_nr_running(struct sched_rt_entity *rt_se)
{
struct rt_rq *group_rq = group_rt_rq(rt_se);
struct task_struct *tsk;
if (group_rq)
return group_rq->rr_nr_running;
tsk = rt_task_of(rt_se);
return (tsk->policy == SCHED_RR) ? 1 : 0;
}
static inline
void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
int prio = rt_se_prio(rt_se);
WARN_ON(!rt_prio(prio));
rt_rq->rt_nr_running += rt_se_nr_running(rt_se);
rt_rq->rr_nr_running += rt_se_rr_nr_running(rt_se);
inc_rt_prio(rt_rq, prio);
inc_rt_migration(rt_se, rt_rq);
inc_rt_group(rt_se, rt_rq);
}
static inline
void dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
{
WARN_ON(!rt_prio(rt_se_prio(rt_se)));
WARN_ON(!rt_rq->rt_nr_running);
rt_rq->rt_nr_running -= rt_se_nr_running(rt_se);
rt_rq->rr_nr_running -= rt_se_rr_nr_running(rt_se);
dec_rt_prio(rt_rq, rt_se_prio(rt_se));
dec_rt_migration(rt_se, rt_rq);
dec_rt_group(rt_se, rt_rq);
}
#if defined(CONFIG_SMP) && defined(CONFIG_RT_GROUP_SCHED)
static void
attach_rt_entity_load_avg(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
rt_se->avg.last_update_time = rt_rq->avg.last_update_time;
rt_rq->avg.util_avg += rt_se->avg.util_avg;
rt_rq->avg.util_sum += rt_se->avg.util_sum;
rt_rq->avg.load_avg += rt_se->avg.load_avg;
rt_rq->avg.load_sum += rt_se->avg.load_sum;
rt_rq->propagate_avg = 1;
rt_rq_util_change(rt_rq);
}
static void
detach_rt_entity_load_avg(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
sub_positive(&rt_rq->avg.util_avg, rt_se->avg.util_avg);
sub_positive(&rt_rq->avg.util_sum, rt_se->avg.util_sum);
sub_positive(&rt_rq->avg.load_avg, rt_se->avg.load_avg);
sub_positive(&rt_rq->avg.load_sum, rt_se->avg.load_sum);
rt_rq->propagate_avg = 1;
rt_rq_util_change(rt_rq);
}
#else
static inline void
attach_rt_entity_load_avg(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) {}
static inline void
detach_rt_entity_load_avg(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se) {}
#endif
/*
* Change rt_se->run_list location unless SAVE && !MOVE
*
* assumes ENQUEUE/DEQUEUE flags match
*/
static inline bool move_entity(unsigned int flags)
{
if ((flags & (DEQUEUE_SAVE | DEQUEUE_MOVE)) == DEQUEUE_SAVE)
return false;
return true;
}
static void __delist_rt_entity(struct sched_rt_entity *rt_se, struct rt_prio_array *array)
{
list_del_init(&rt_se->run_list);
if (list_empty(array->queue + rt_se_prio(rt_se)))
__clear_bit(rt_se_prio(rt_se), array->bitmap);
rt_se->on_list = 0;
}
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rt_prio_array *array = &rt_rq->active;
struct rt_rq *group_rq = group_rt_rq(rt_se);
struct list_head *queue = array->queue + rt_se_prio(rt_se);
/*
* Don't enqueue the group if its throttled, or when empty.
* The latter is a consequence of the former when a child group
* get throttled and the current group doesn't have any other
* active members.
*/
if (group_rq && (rt_rq_throttled(group_rq) || !group_rq->rt_nr_running)) {
if (rt_se->on_list)
__delist_rt_entity(rt_se, array);
return;
}
if (move_entity(flags)) {
WARN_ON_ONCE(rt_se->on_list);
if (flags & ENQUEUE_HEAD)
list_add(&rt_se->run_list, queue);
else
list_add_tail(&rt_se->run_list, queue);
__set_bit(rt_se_prio(rt_se), array->bitmap);
rt_se->on_list = 1;
}
rt_se->on_rq = 1;
update_rt_load_avg(rq_clock_task(rq_of_rt_rq(rt_rq)), rt_se);
if (rt_entity_is_task(rt_se) && !rt_se->avg.last_update_time)
attach_rt_entity_load_avg(rt_rq, rt_se);
inc_rt_tasks(rt_se, rt_rq);
}
static void __dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rt_prio_array *array = &rt_rq->active;
if (move_entity(flags)) {
WARN_ON_ONCE(!rt_se->on_list);
__delist_rt_entity(rt_se, array);
}
rt_se->on_rq = 0;
update_rt_load_avg(rq_clock_task(rq_of_rt_rq(rt_rq)), rt_se);
dec_rt_tasks(rt_se, rt_rq);
}
/*
* Because the prio of an upper entry depends on the lower
* entries, we must remove entries top - down.
*/
static void dequeue_rt_stack(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct sched_rt_entity *back = NULL;
for_each_sched_rt_entity(rt_se) {
rt_se->back = back;
back = rt_se;
}
dequeue_top_rt_rq(rt_rq_of_se(back));
for (rt_se = back; rt_se; rt_se = rt_se->back) {
if (on_rt_rq(rt_se))
__dequeue_rt_entity(rt_se, flags);
}
}
static void enqueue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rq *rq = rq_of_rt_se(rt_se);
dequeue_rt_stack(rt_se, flags);
for_each_sched_rt_entity(rt_se)
__enqueue_rt_entity(rt_se, flags);
enqueue_top_rt_rq(&rq->rt);
}
static void dequeue_rt_entity(struct sched_rt_entity *rt_se, unsigned int flags)
{
struct rq *rq = rq_of_rt_se(rt_se);
dequeue_rt_stack(rt_se, flags);
for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq && rt_rq->rt_nr_running)
__enqueue_rt_entity(rt_se, flags);
}
enqueue_top_rt_rq(&rq->rt);
}
/*
* Adding/removing a task to/from a priority array:
*/
static void
enqueue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
schedtune_enqueue_task(p, cpu_of(rq));
if (flags & ENQUEUE_WAKEUP)
rt_se->timeout = 0;
enqueue_rt_entity(rt_se, flags);
walt_inc_cumulative_runnable_avg(rq, p);
if (!task_current(rq, p) && p->nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
}
static void dequeue_task_rt(struct rq *rq, struct task_struct *p, int flags)
{
struct sched_rt_entity *rt_se = &p->rt;
schedtune_dequeue_task(p, cpu_of(rq));
update_curr_rt(rq);
dequeue_rt_entity(rt_se, flags);
walt_dec_cumulative_runnable_avg(rq, p);
dequeue_pushable_task(rq, p);
}
/*
* Put task to the head or the end of the run list without the overhead of
* dequeue followed by enqueue.
*/
static void
requeue_rt_entity(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se, int head)
{
if (on_rt_rq(rt_se)) {
struct rt_prio_array *array = &rt_rq->active;
struct list_head *queue = array->queue + rt_se_prio(rt_se);
if (head)
list_move(&rt_se->run_list, queue);
else
list_move_tail(&rt_se->run_list, queue);
}
}
static void requeue_task_rt(struct rq *rq, struct task_struct *p, int head)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq;
for_each_sched_rt_entity(rt_se) {
rt_rq = rt_rq_of_se(rt_se);
requeue_rt_entity(rt_rq, rt_se, head);
}
}
static void yield_task_rt(struct rq *rq)
{
requeue_task_rt(rq, rq->curr, 0);
}
#ifdef CONFIG_SMP
/* TODO:
* attach/detach/migrate_task_rt_rq() for load tracking
*/
#ifdef CONFIG_SCHED_USE_FLUID_RT
static int find_lowest_rq(struct task_struct *task, int wake_flags);
#else
static int find_lowest_rq(struct task_struct *task);
#endif
static int
select_task_rq_rt(struct task_struct *p, int cpu, int sd_flag, int flags,
int sibling_count_hint)
{
struct task_struct *curr;
struct rq *rq;
/* For anything but wake ups, just return the task_cpu */
if (sd_flag != SD_BALANCE_WAKE && sd_flag != SD_BALANCE_FORK)
goto out;
rq = cpu_rq(cpu);
rcu_read_lock();
curr = READ_ONCE(rq->curr); /* unlocked access */
#ifdef CONFIG_SCHED_USE_FLUID_RT
if (curr) {
int target = find_lowest_rq(p, flags);
/*
* Even though the destination CPU is running
* a higher priority task, FluidRT can bother moving it
* when its utilization is very small, and the other CPU is too busy
* to accomodate the p in the point of priority and utilization.
*
* BTW, if the curr has higher priority than p, FluidRT tries to find
* the other CPUs first. In the worst case, curr can be victim, if it
* has very small utilization.
*/
if (likely(target != -1)) {
cpu = target;
}
}
#else
/*
* If the current task on @p's runqueue is an RT task, then
* try to see if we can wake this RT task up on another
* runqueue. Otherwise simply start this RT task
* on its current runqueue.
*
* We want to avoid overloading runqueues. If the woken
* task is a higher priority, then it will stay on this CPU
* and the lower prio task should be moved to another CPU.
* Even though this will probably make the lower prio task
* lose its cache, we do not want to bounce a higher task
* around just because it gave up its CPU, perhaps for a
* lock?
*
* For equal prio tasks, we just let the scheduler sort it out.
*
* Otherwise, just let it ride on the affined RQ and the
* post-schedule router will push the preempted task away
*
* This test is optimistic, if we get it wrong the load-balancer
* will have to sort it out.
*/
if (curr && unlikely(rt_task(curr)) &&
(curr->nr_cpus_allowed < 2 ||
curr->prio <= p->prio)) {
int target = find_lowest_rq(p);
/*
* Don't bother moving it if the destination CPU is
* not running a lower priority task.
*/
if (target != -1 &&
p->prio < cpu_rq(target)->rt.highest_prio.curr)
cpu = target;
}
#endif
rcu_read_unlock();
out:
#ifdef CONFIG_SCHED_USE_FLUID_RT
if (cpu >= 6)
trace_sched_fluid_stat(p, &p->rt.avg, cpu, "BIG_ASSIGED");
#endif
return cpu;
}
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Called within set_task_rq() right before setting a task's cpu. The
* caller only guarantees p->pi_lock is held; no other assumptions,
* including the state of rq->lock, should be made.
*/
void set_task_rq_rt(struct sched_rt_entity *rt_se,
struct rt_rq *prev, struct rt_rq *next)
{
u64 p_last_update_time;
u64 n_last_update_time;
if (!sched_feat(ATTACH_AGE_LOAD))
return;
/*
* We are supposed to update the task to "current" time, then its up to
* date and ready to go to new CPU/rt_rq. But we have difficulty in
* getting what current time is, so simply throw away the out-of-date
* time. This will result in the wakee task is less decayed, but giving
* the wakee more load sounds not bad.
*/
if (!(rt_se->avg.last_update_time && prev))
return;
#ifndef CONFIG_64BIT
{
u64 p_last_update_time_copy;
u64 n_last_update_time_copy;
do {
p_last_update_time_copy = prev->load_last_update_time_copy;
n_last_update_time_copy = next->load_last_update_time_copy;
smp_rmb();
p_last_update_time = prev->avg.last_update_time;
n_last_update_time = next->avg.last_update_time;
} while (p_last_update_time != p_last_update_time_copy ||
n_last_update_time != n_last_update_time_copy);
}
#else
p_last_update_time = prev->avg.last_update_time;
n_last_update_time = next->avg.last_update_time;
#endif
__update_load_avg(p_last_update_time, cpu_of(rq_of_rt_rq(prev)),
&rt_se->avg, scale_load_down(NICE_0_LOAD), 0, NULL);
rt_se->avg.last_update_time = n_last_update_time;
}
#endif /* CONFIG_RT_GROUP_SCHED */
#ifndef CONFIG_64BIT
static inline u64 rt_rq_last_update_time(struct rt_rq *rt_rq)
{
u64 last_update_time_copy;
u64 last_update_time;
do {
last_update_time_copy = rt_rq->load_last_update_time_copy;
smp_rmb();
last_update_time = rt_rq->avg.last_update_time;
} while (last_update_time != last_update_time_copy);
return last_update_time;
}
#else
static inline u64 rt_rq_last_update_time(struct rt_rq *rt_rq)
{
return rt_rq->avg.last_update_time;
}
#endif
/*
* Synchronize entity load avg of dequeued entity without locking
* the previous rq.
*/
void sync_rt_entity_load_avg(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
u64 last_update_time;
last_update_time = rt_rq_last_update_time(rt_rq);
__update_load_avg(last_update_time, cpu_of(rq_of_rt_rq(rt_rq)),
&rt_se->avg, scale_load_down(NICE_0_LOAD), rt_rq->curr == rt_se, NULL);
}
/*
* Task first catches up with rt_rq, and then subtract
* itself from the rt_rq (task must be off the queue now).
*/
static void remove_rt_entity_load_avg(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
/*
* tasks cannot exit without having gone through wake_up_new_task() ->
* post_init_entity_util_avg() which will have added things to the
* rt_rq, so we can remove unconditionally.
*
* Similarly for groups, they will have passed through
* post_init_entity_util_avg() before unregister_sched_fair_group()
* calls this.
*/
sync_rt_entity_load_avg(rt_se);
atomic_long_add(rt_se->avg.load_avg, &rt_rq->removed_load_avg);
atomic_long_add(rt_se->avg.util_avg, &rt_rq->removed_util_avg);
}
#ifdef CONFIG_RT_GROUP_SCHED
static void attach_task_rt_rq(struct task_struct *p)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
u64 now = rq_clock_task(rq_of_rt_rq(rt_rq));
update_rt_load_avg(now, rt_se);
attach_rt_entity_load_avg(rt_rq, rt_se);
}
static void detach_task_rt_rq(struct task_struct *p)
{
struct sched_rt_entity *rt_se = &p->rt;
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
u64 now = rq_clock_task(rq_of_rt_rq(rt_rq));
update_rt_load_avg(now, rt_se);
detach_rt_entity_load_avg(rt_rq, rt_se);
}
#endif
static void migrate_task_rq_rt(struct task_struct *p)
{
/*
* We are supposed to update the task to "current" time, then its up to date
* and ready to go to new CPU/cfs_rq. But we have difficulty in getting
* what current time is, so simply throw away the out-of-date time. This
* will result in the wakee task is less decayed, but giving the wakee more
* load sounds not bad.
*/
remove_rt_entity_load_avg(&p->rt);
/* Tell new CPU we are migrated */
p->rt.avg.last_update_time = 0;
/* We have migrated, no longer consider this task hot */
p->se.exec_start = 0;
}
static void task_dead_rt(struct task_struct *p)
{
remove_rt_entity_load_avg(&p->rt);
}
#ifdef CONFIG_RT_GROUP_SCHED
static void task_set_group_rt(struct task_struct *p)
{
set_task_rq(p, task_cpu(p));
}
static void task_move_group_rt(struct task_struct *p)
{
detach_task_rt_rq(p);
set_task_rq(p, task_cpu(p));
#ifdef CONFIG_SMP
/* Tell se's cfs_rq has been changed -- migrated */
p->se.avg.last_update_time = 0;
#endif
attach_task_rt_rq(p);
}
static void task_change_group_rt(struct task_struct *p, int type)
{
switch (type) {
case TASK_SET_GROUP:
task_set_group_rt(p);
break;
case TASK_MOVE_GROUP:
task_move_group_rt(p);
break;
}
}
#endif
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
/*
* Current can't be migrated, useless to reschedule,
* let's hope p can move out.
*/
if (rq->curr->nr_cpus_allowed == 1 ||
!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
return;
/*
* p is migratable, so let's not schedule it and
* see if it is pushed or pulled somewhere else.
*/
if (p->nr_cpus_allowed != 1
&& cpupri_find(&rq->rd->cpupri, p, NULL))
return;
/*
* There appears to be other cpus that can accept
* current and none to run 'p', so lets reschedule
* to try and push current away:
*/
requeue_task_rt(rq, p, 1);
resched_curr(rq);
}
/* Give new sched_entity start runnable values to heavy its load in infant time */
void init_rt_entity_runnable_average(struct sched_rt_entity *rt_se)
{
struct sched_avg *sa = &rt_se->avg;
sa->last_update_time = 0;
sa->period_contrib = 1023;
/*
* Tasks are intialized with zero load.
* Load is not actually used by RT, but can be inherited into fair task.
*/
sa->load_avg = 0;
sa->load_sum = 0;
/*
* At this point, util_avg won't be used in select_task_rq_rt anyway
*/
sa->util_avg = 0;
sa->util_sum = 0;
/* when this task enqueue'ed, it will contribute to its cfs_rq's load_avg */
}
#else
void init_rt_entity_runnable_average(struct sched_rt_entity *rt_se) { }
#endif /* CONFIG_SMP */
#ifdef CONFIG_SCHED_USE_FLUID_RT
static inline void set_victim_flag(struct task_struct *p)
{
p->victim_flag = 1;
}
static inline void clear_victim_flag(struct task_struct *p)
{
p->victim_flag = 0;
}
static inline bool test_victim_flag(struct task_struct *p)
{
if (p->victim_flag)
return true;
else
return false;
}
#else
static inline bool test_victim_flag(struct task_struct *p) { return false; }
static inline void clear_victim_flag(struct task_struct *p) {}
#endif
/*
* Preempt the current task with a newly woken task if needed:
*/
static void check_preempt_curr_rt(struct rq *rq, struct task_struct *p, int flags)
{
if (p->prio < rq->curr->prio) {
resched_curr(rq);
return;
} else if (test_victim_flag(p)) {
requeue_task_rt(rq, p, 1);
resched_curr(rq);
return;
}
#ifdef CONFIG_SMP
/*
* If:
*
* - the newly woken task is of equal priority to the current task
* - the newly woken task is non-migratable while current is migratable
* - current will be preempted on the next reschedule
*
* we should check to see if current can readily move to a different
* cpu. If so, we will reschedule to allow the push logic to try
* to move current somewhere else, making room for our non-migratable
* task.
*/
if (p->prio == rq->curr->prio && !test_tsk_need_resched(rq->curr))
check_preempt_equal_prio(rq, p);
#endif
}
static struct sched_rt_entity *pick_next_rt_entity(struct rq *rq,
struct rt_rq *rt_rq)
{
struct rt_prio_array *array = &rt_rq->active;
struct sched_rt_entity *next = NULL;
struct list_head *queue;
int idx;
idx = sched_find_first_bit(array->bitmap);
BUG_ON(idx >= MAX_RT_PRIO);
queue = array->queue + idx;
if (SCHED_WARN_ON(list_empty(queue)))
return NULL;
next = list_entry(queue->next, struct sched_rt_entity, run_list);
return next;
}
static struct task_struct *_pick_next_task_rt(struct rq *rq)
{
struct sched_rt_entity *rt_se;
struct task_struct *p;
struct rt_rq *rt_rq = &rq->rt;
u64 now = rq_clock_task(rq);
do {
rt_se = pick_next_rt_entity(rq, rt_rq);
if (unlikely(!rt_se))
return NULL;
update_rt_load_avg(now, rt_se);
rt_rq->curr = rt_se;
rt_rq = group_rt_rq(rt_se);
} while (rt_rq);
p = rt_task_of(rt_se);
p->se.exec_start = now;
return p;
}
extern int update_rt_rq_load_avg(u64 now, int cpu, struct rt_rq *rt_rq, int running);
static struct task_struct *
pick_next_task_rt(struct rq *rq, struct task_struct *prev, struct rq_flags *rf)
{
struct task_struct *p;
struct rt_rq *rt_rq = &rq->rt;
if (need_pull_rt_task(rq, prev)) {
/*
* This is OK, because current is on_cpu, which avoids it being
* picked for load-balance and preemption/IRQs are still
* disabled avoiding further scheduler activity on it and we're
* being very careful to re-start the picking loop.
*/
rq_unpin_lock(rq, rf);
pull_rt_task(rq);
rq_repin_lock(rq, rf);
/*
* pull_rt_task() can drop (and re-acquire) rq->lock; this
* means a dl or stop task can slip in, in which case we need
* to re-start task selection.
*/
if (unlikely((rq->stop && task_on_rq_queued(rq->stop)) ||
rq->dl.dl_nr_running))
return RETRY_TASK;
}
/*
* We may dequeue prev's rt_rq in put_prev_task().
* So, we update time before rt_nr_running check.
*/
if (prev->sched_class == &rt_sched_class)
update_curr_rt(rq);
if (!rt_rq->rt_queued)
return NULL;
put_prev_task(rq, prev);
p = _pick_next_task_rt(rq);
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
queue_push_tasks(rq);
if (p)
update_rt_rq_load_avg(rq_clock_task(rq), cpu_of(rq), rt_rq,
rq->curr->sched_class == &rt_sched_class);
clear_victim_flag(p);
return p;
}
static void put_prev_task_rt(struct rq *rq, struct task_struct *p)
{
struct sched_rt_entity *rt_se = &p->rt;
u64 now = rq_clock_task(rq);
update_curr_rt(rq);
/*
* The previous task needs to be made eligible for pushing
* if it is still active
*/
if (on_rt_rq(&p->rt) && p->nr_cpus_allowed > 1)
enqueue_pushable_task(rq, p);
for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
if (rt_se->on_rq)
update_rt_load_avg(now, rt_se);
rt_rq->curr = NULL;
}
}
#ifdef CONFIG_SMP
#ifdef CONFIG_RT_GROUP_SCHED
void rt_rq_util_change(struct rt_rq *rt_rq)
{
if (&this_rq()->rt == rt_rq)
cpufreq_update_util(rt_rq->rq, SCHED_CPUFREQ_RT);
}
/* Take into account change of utilization of a child task group */
static inline void
update_tg_rt_util(struct rt_rq *cfs_rq, struct sched_rt_entity *rt_se)
{
struct rt_rq *grt_rq = rt_se->my_q;
long delta = grt_rq->avg.util_avg - rt_se->avg.util_avg;
/* Nothing to update */
if (!delta)
return;
/* Set new sched_rt_entity's utilization */
rt_se->avg.util_avg = grt_rq->avg.util_avg;
rt_se->avg.util_sum = rt_se->avg.util_avg * LOAD_AVG_MAX;
/* Update parent rt_rq utilization */
add_positive(&cfs_rq->avg.util_avg, delta);
cfs_rq->avg.util_sum = cfs_rq->avg.util_avg * LOAD_AVG_MAX;
}
/* Take into account change of load of a child task group */
static inline void
update_tg_rt_load(struct rt_rq *rt_rq, struct sched_rt_entity *rt_se)
{
struct rt_rq *grt_rq = rt_se->my_q;
long delta = grt_rq->avg.load_avg - rt_se->avg.load_avg;
/*
* TODO: Need to consider the TG group update
* for RT RQ
*/
/* Nothing to update */
if (!delta)
return;
/* Set new sched_rt_entity's load */
rt_se->avg.load_avg = grt_rq->avg.load_avg;
rt_se->avg.load_sum = rt_se->avg.load_avg * LOAD_AVG_MAX;
/* Update parent cfs_rq load */
add_positive(&rt_rq->avg.load_avg, delta);
rt_rq->avg.load_sum = rt_rq->avg.load_avg * LOAD_AVG_MAX;
/*
* TODO: If the sched_entity is already enqueued, should we have to update the
* runnable load avg.
*/
}
static inline int test_and_clear_tg_rt_propagate(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_se->my_q;
if (!rt_rq->propagate_avg)
return 0;
rt_rq->propagate_avg = 0;
return 1;
}
/* Update task and its cfs_rq load average */
static inline int propagate_entity_rt_load_avg(struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq;
if (rt_entity_is_task(rt_se))
return 0;
if (!test_and_clear_tg_rt_propagate(rt_se))
return 0;
rt_rq = rt_rq_of_se(rt_se);
rt_rq->propagate_avg = 1;
update_tg_rt_util(rt_rq, rt_se);
update_tg_rt_load(rt_rq, rt_se);
return 1;
}
#else
static inline int propagate_entity_rt_load_avg(struct sched_rt_entity *rt_se) { return 1; };
#endif
void update_rt_load_avg(u64 now, struct sched_rt_entity *rt_se)
{
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
struct rq *rq = rq_of_rt_rq(rt_rq);
int cpu = cpu_of(rq);
/*
* Track task load average for carrying it to new CPU after migrated.
*/
if (rt_se->avg.last_update_time)
__update_load_avg(now, cpu, &rt_se->avg, scale_load_down(NICE_0_LOAD),
rt_rq->curr == rt_se, NULL);
update_rt_rq_load_avg(now, cpu, rt_rq, rt_rq->curr == rt_se);
propagate_entity_rt_load_avg(rt_se);
#ifdef CONFIG_RT_GROUP_SCHED
if (entity_is_task(rt_se))
trace_sched_rt_load_avg_task(rt_task_of(rt_se), &rt_se->avg);
#endif
}
/* Only try algorithms three times */
#define RT_MAX_TRIES 3
static int pick_rt_task(struct rq *rq, struct task_struct *p, int cpu)
{
if (!task_running(rq, p) &&
cpumask_test_cpu(cpu, &p->cpus_allowed))
return 1;
return 0;
}
/*
* Return the highest pushable rq's task, which is suitable to be executed
* on the cpu, NULL otherwise
*/
static struct task_struct *pick_highest_pushable_task(struct rq *rq, int cpu)
{
struct plist_head *head = &rq->rt.pushable_tasks;
struct task_struct *p;
if (!has_pushable_tasks(rq))
return NULL;
plist_for_each_entry(p, head, pushable_tasks) {
if (pick_rt_task(rq, p, cpu))
return p;
}
return NULL;
}
static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
#ifdef CONFIG_SCHED_USE_FLUID_RT
static inline int weight_from_rtprio(int prio)
{
int idx = (prio >> 1);
if (!rt_prio(prio))
return sched_prio_to_weight[prio - MAX_RT_PRIO];
if ((idx << 1) == prio)
return rtprio_to_weight[idx];
else
return ((rtprio_to_weight[idx] + rtprio_to_weight[idx+1]) >> 1);
}
/* Affordable CPU:
* to find the best CPU in which the data is kept in cache-hot
*
* In most of time, RT task is invoked because,
* Case - I : it is already scheduled some time ago, or
* Case - II: it is requested by some task without timedelay
*
* In case-I, it's hardly to find the best CPU in cache-hot if the time is relatively long.
* But in case-II, waker CPU is likely to keep the cache-hot data useful to wakee RT task.
*/
static inline int affordable_cpu(int cpu, unsigned long task_load)
{
/*
* If the task.state is 'TASK_INTERRUPTIBLE',
* she is likely to call 'schedule()' explicitely, for waking up RT task.
* and have something in common with it.
*/
if (cpu_curr(cpu)->state != TASK_INTERRUPTIBLE)
return 0;
/*
* Waker CPU must accommodate the target RT task.
*/
if (capacity_of(cpu) <= task_load)
return 0;
/*
* Future work (More concerns if needed):
* - Min opportunity cost between the eviction of tasks and dismiss of target RT
* : If evicted tasks are expecting too many damage for its execution,
* Target RT should not be this CPU.
* load(RT) >= Capa(CPU)/3 && load(evicted tasks) >= Capa(CPU)/3
* - Identifying the relation:
* : Is it possible to identify the relation (such as mutex owner and waiter)
* -
*/
return 1;
}
extern unsigned long task_util(struct task_struct *p);
unsigned long frt_cpu_util_wake(int cpu, struct task_struct *p)
{
struct cfs_rq *cfs_rq = &cpu_rq(cpu)->cfs;
struct rt_rq *rt_rq = &cpu_rq(cpu)->rt;
unsigned int util;
util = READ_ONCE(cfs_rq->avg.util_avg) + READ_ONCE(rt_rq->avg.util_avg);
#ifdef CONFIG_SCHED_WALT
/*
* WALT does not decay idle tasks in the same manner
* as PELT, so it makes little sense to subtract task
* utilization from cpu utilization. Instead just use
* cpu_util for this case.
*/
if (!walt_disabled && sysctl_sched_use_walt_cpu_util)
return cpu_util(cpu);
#endif
/* Task has no contribution or is new */
if (cpu != task_cpu(p) || !READ_ONCE(p->se.avg.last_update_time))
return util;
/* Discount task's blocked util from CPU's util */
util -= min_t(unsigned int, util, task_util(p));
return min_t(unsigned long, util, capacity_orig_of(cpu));
}
static inline int cpu_selected(int cpu) { return (nr_cpu_ids > cpu && cpu >= 0); }
/*
* Must find the victim or recessive (not in lowest_mask)
*
*/
/* Future-safe accessor for struct task_struct's cpus_allowed. */
#define rttsk_cpus_allowed(tsk) (&(tsk)->cpus_allowed)
static int find_victim_rt_rq(struct task_struct *task, const struct cpumask *sg_cpus, int *best_cpu) {
unsigned int i;
unsigned long victim_rtweight, target_rtweight, min_rtweight;
unsigned int victim_cpu_cap, min_cpu_cap = arch_scale_cpu_capacity(NULL, task_cpu(task));
bool victim_rt = true;
if (!rt_task(task))
return *best_cpu;
target_rtweight = task->rt.avg.util_avg * weight_from_rtprio(task->prio);
min_rtweight = target_rtweight;
for_each_cpu_and(i, sg_cpus, rttsk_cpus_allowed(task)) {
struct task_struct *victim = cpu_rq(i)->curr;
if (victim->nr_cpus_allowed < 2)
continue;
if (rt_task(victim)) {
victim_cpu_cap = arch_scale_cpu_capacity(NULL, i);
victim_rtweight = victim->rt.avg.util_avg * weight_from_rtprio(victim->prio);
if (min_cpu_cap == victim_cpu_cap) {
if (victim_rtweight < min_rtweight) {
min_rtweight = victim_rtweight;
*best_cpu = i;
min_cpu_cap = victim_cpu_cap;
}
} else {
/*
* It's necessary to un-cap the cpu capacity when comparing
* utilization of each CPU. This is why the Fluid RT tries to give
* the green light on big CPU to the long-run RT task
* in accordance with the priority.
*/
if (victim_rtweight * min_cpu_cap < min_rtweight * victim_cpu_cap) {
min_rtweight = victim_rtweight;
*best_cpu = i;
min_cpu_cap = victim_cpu_cap;
}
}
} else {
/* If Non-RT CPU is exist, select it first. */
*best_cpu = i;
victim_rt = false;
break;
}
}
if (*best_cpu >= 0 && victim_rt) {
set_victim_flag(cpu_rq(*best_cpu)->curr);
}
if (victim_rt)
trace_sched_fluid_stat(task, &task->rt.avg, *best_cpu, "VICTIM-FAIR");
else
trace_sched_fluid_stat(task, &task->rt.avg, *best_cpu, "VICTIM-RT");
return *best_cpu;
}
static int check_cache_hot(struct task_struct *task, int flags, int *best_cpu)
{
int cpu = smp_processor_id();
return false;
/*
* 3. Cache hot : packing the callee and caller,
* when there is nothing to run except callee, or
* wake_flags are set.
*/
/* FUTURE WORK: Hierarchical cache hot */
if (!(flags & WF_SYNC))
return false;
if (cpumask_test_cpu(*best_cpu, cpu_coregroup_mask(cpu))) {
task->rt.sync_flag = 1;
*best_cpu = cpu;
trace_sched_fluid_stat(task, &task->rt.avg, *best_cpu, "CACHE-HOT");
return true;
}
return false;
}
static int find_idle_cpu(struct task_struct *task, int wake_flags)
{
int cpu, best_cpu = -1;
int cpu_prio, max_prio = -1;
u64 cpu_load, min_load = ULLONG_MAX;
struct cpumask candidate_cpus;
struct frt_dom *dom, *prefer_dom;
cpu = frt_find_prefer_cpu(task);
prefer_dom = dom = per_cpu(frt_rqs, cpu);
if (unlikely(!dom))
return best_cpu;
cpumask_and(&candidate_cpus, &task->cpus_allowed, cpu_active_mask);
cpumask_and(&candidate_cpus, &candidate_cpus, get_activated_cpus());
if (unlikely(cpumask_empty(&candidate_cpus)))
cpumask_copy(&candidate_cpus, &task->cpus_allowed);
do {
for_each_cpu_and(cpu, &dom->cpus, &candidate_cpus) {
if (!idle_cpu(cpu))
continue;
cpu_prio = cpu_rq(cpu)->rt.highest_prio.curr;
if (cpu_prio < max_prio)
continue;
cpu_load = frt_cpu_util_wake(cpu, task) + task_util(task);
if (cpu_load > capacity_orig_of(cpu))
continue;
if ((cpu_prio > max_prio) || (cpu_load < min_load) ||
(cpu_load == min_load && task_cpu(task) == cpu)) {
min_load = cpu_load;
max_prio = cpu_prio;
best_cpu = cpu;
}
}
if (cpu_selected(best_cpu)) {
if (check_cache_hot(task, wake_flags, &best_cpu))
return best_cpu;
trace_sched_fluid_stat(task, &task->rt.avg, best_cpu, "IDLE-FIRST");
return best_cpu;
}
dom = dom->next;
} while (dom != prefer_dom);
return best_cpu;
}
static int find_recessive_cpu(struct task_struct *task, int wake_flags)
{
int cpu, best_cpu = -1;
u64 cpu_load, min_load = ULLONG_MAX;
struct cpumask *lowest_mask;
struct cpumask candidate_cpus;
struct frt_dom *dom, *prefer_dom;
lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
/* Make sure the mask is initialized first */
if (unlikely(!lowest_mask)) {
trace_sched_fluid_stat(task, &task->rt.avg, best_cpu, "NA LOWESTMSK");
return best_cpu;
}
/* update the per-cpu local_cpu_mask (lowest_mask) */
cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask);
cpumask_and(&candidate_cpus, &task->cpus_allowed, lowest_mask);
cpumask_and(&candidate_cpus, &candidate_cpus, cpu_active_mask);
cpu = frt_find_prefer_cpu(task);
prefer_dom = dom = per_cpu(frt_rqs, cpu);
if (unlikely(!dom))
return best_cpu;
do {
for_each_cpu_and(cpu, &dom->cpus, &candidate_cpus) {
cpu_load = frt_cpu_util_wake(cpu, task) + task_util(task);
if (cpu_load > capacity_orig_of(cpu))
continue;
if (cpu_load < min_load ||
(cpu_load == min_load && task_cpu(task) == cpu)) {
min_load = cpu_load;
best_cpu = cpu;
}
}
if (cpu_selected(best_cpu)) {
if (check_cache_hot(task, wake_flags, &best_cpu))
return best_cpu;
trace_sched_fluid_stat(task, &task->rt.avg, best_cpu,
rt_task(cpu_rq(best_cpu)->curr) ? "RT-RECESS" : "FAIR-RECESS");
return best_cpu;
}
dom = dom->next;
} while (dom != prefer_dom);
return best_cpu;
}
static int find_lowest_rq_fluid(struct task_struct *task, int wake_flags)
{
int cpu, best_cpu = -1;
if (task->nr_cpus_allowed == 1) {
trace_sched_fluid_stat(task, &task->rt.avg, best_cpu, "NA ALLOWED");
goto out; /* No other targets possible */
}
/*
*
* Fluid Sched Core selection procedure:
*
* 1. idle CPU selection (cache-hot cpu first)
* 2. recessive task first (cache-hot cpu first)
* 3. victim task first (prev_cpu first)
*/
/* 1. idle CPU selection */
best_cpu = find_idle_cpu(task, wake_flags);
if (cpu_selected(best_cpu))
goto out;
/* 2. recessive task first */
best_cpu = find_recessive_cpu(task, wake_flags);
if (cpu_selected(best_cpu))
goto out;
/*
* 3. victim task first
*/
for_each_cpu(cpu, cpu_active_mask) {
if (cpu != cpumask_first(cpu_coregroup_mask(cpu)))
continue;
if (find_victim_rt_rq(task, cpu_coregroup_mask(cpu), &best_cpu) != -1)
break;
}
out:
if (best_cpu == -1)
best_cpu = task_rq(task)->cpu;
if (!cpumask_test_cpu(best_cpu, cpu_online_mask)) {
trace_sched_fluid_stat(task, &task->rt.avg, best_cpu, "NOTHING_VALID");
best_cpu = -1;
}
return best_cpu;
}
#endif /* CONFIG_SCHED_USE_FLUID_RT */
#ifdef CONFIG_SCHED_USE_FLUID_RT
static int find_lowest_rq(struct task_struct *task, int wake_flags)
#else
static int find_lowest_rq(struct task_struct *task)
#endif
{
#ifdef CONFIG_SCHED_USE_FLUID_RT
return find_lowest_rq_fluid(task, wake_flags);
#else
struct sched_domain *sd;
struct cpumask *lowest_mask = this_cpu_cpumask_var_ptr(local_cpu_mask);
int this_cpu = smp_processor_id();
int cpu = task_cpu(task);
/* Make sure the mask is initialized first */
if (unlikely(!lowest_mask))
return -1;
if (task->nr_cpus_allowed == 1)
return -1; /* No other targets possible */
if (!cpupri_find(&task_rq(task)->rd->cpupri, task, lowest_mask))
return -1; /* No targets found */
/*
* At this point we have built a mask of cpus representing the
* lowest priority tasks in the system. Now we want to elect
* the best one based on our affinity and topology.
*
* We prioritize the last cpu that the task executed on since
* it is most likely cache-hot in that location.
*/
if (cpumask_test_cpu(cpu, lowest_mask))
return cpu;
/*
* Otherwise, we consult the sched_domains span maps to figure
* out which cpu is logically closest to our hot cache data.
*/
if (!cpumask_test_cpu(this_cpu, lowest_mask))
this_cpu = -1; /* Skip this_cpu opt if not among lowest */
rcu_read_lock();
for_each_domain(cpu, sd) {
if (sd->flags & SD_WAKE_AFFINE) {
int best_cpu;
/*
* "this_cpu" is cheaper to preempt than a
* remote processor.
*/
if (this_cpu != -1 &&
cpumask_test_cpu(this_cpu, sched_domain_span(sd))) {
rcu_read_unlock();
return this_cpu;
}
best_cpu = cpumask_first_and(lowest_mask,
sched_domain_span(sd));
if (best_cpu < nr_cpu_ids) {
rcu_read_unlock();
return best_cpu;
}
}
}
rcu_read_unlock();
/*
* And finally, if there were no matches within the domains
* just give the caller *something* to work with from the compatible
* locations.
*/
if (this_cpu != -1)
return this_cpu;
cpu = cpumask_any(lowest_mask);
if (cpu < nr_cpu_ids)
return cpu;
return -1;
#endif /* CONFIG_SCHED_USE_FLUID_RT */
}
/* Will lock the rq it finds */
static struct rq *find_lock_lowest_rq(struct task_struct *task, struct rq *rq)
{
struct rq *lowest_rq = NULL;
int tries;
int cpu;
for (tries = 0; tries < RT_MAX_TRIES; tries++) {
#ifdef CONFIG_SCHED_USE_FLUID_RT
cpu = find_lowest_rq(task, 0);
#else
cpu = find_lowest_rq(task);
#endif
if ((cpu == -1) || (cpu == rq->cpu))
break;
lowest_rq = cpu_rq(cpu);
if (lowest_rq->rt.highest_prio.curr <= task->prio)
{
/*
* Target rq has tasks of equal or higher priority,
* retrying does not release any lock and is unlikely
* to yield a different result.
*/
lowest_rq = NULL;
break;
}
/* if the prio of this runqueue changed, try again */
if (double_lock_balance(rq, lowest_rq)) {
/*
* We had to unlock the run queue. In
* the mean time, task could have
* migrated already or had its affinity changed.
* Also make sure that it wasn't scheduled on its rq.
*/
if (unlikely(task_rq(task) != rq ||
!cpumask_test_cpu(lowest_rq->cpu, &task->cpus_allowed) ||
task_running(rq, task) ||
!rt_task(task) ||
!task_on_rq_queued(task))) {
double_unlock_balance(rq, lowest_rq);
lowest_rq = NULL;
break;
}
}
/* If this rq is still suitable use it. */
if (lowest_rq->rt.highest_prio.curr > task->prio)
break;
/* try again */
double_unlock_balance(rq, lowest_rq);
lowest_rq = NULL;
}
return lowest_rq;
}
static struct task_struct *pick_next_pushable_task(struct rq *rq)
{
struct task_struct *p;
if (!has_pushable_tasks(rq))
return NULL;
p = plist_first_entry(&rq->rt.pushable_tasks,
struct task_struct, pushable_tasks);
BUG_ON(rq->cpu != task_cpu(p));
BUG_ON(task_current(rq, p));
BUG_ON(p->nr_cpus_allowed <= 1);
BUG_ON(!task_on_rq_queued(p));
BUG_ON(!rt_task(p));
return p;
}
/*
* If the current CPU has more than one RT task, see if the non
* running task can migrate over to a CPU that is running a task
* of lesser priority.
*/
static int push_rt_task(struct rq *rq)
{
struct task_struct *next_task;
struct rq *lowest_rq;
int ret = 0;
if (!rq->rt.overloaded)
return 0;
next_task = pick_next_pushable_task(rq);
if (!next_task)
return 0;
retry:
if (unlikely(next_task == rq->curr)) {
WARN_ON(1);
return 0;
}
/*
* It's possible that the next_task slipped in of
* higher priority than current. If that's the case
* just reschedule current.
*/
if (unlikely(next_task->prio < rq->curr->prio)) {
resched_curr(rq);
return 0;
}
/* We might release rq lock */
get_task_struct(next_task);
/* find_lock_lowest_rq locks the rq if found */
lowest_rq = find_lock_lowest_rq(next_task, rq);
if (!lowest_rq) {
struct task_struct *task;
/*
* find_lock_lowest_rq releases rq->lock
* so it is possible that next_task has migrated.
*
* We need to make sure that the task is still on the same
* run-queue and is also still the next task eligible for
* pushing.
*/
task = pick_next_pushable_task(rq);
if (task == next_task) {
/*
* The task hasn't migrated, and is still the next
* eligible task, but we failed to find a run-queue
* to push it to. Do not retry in this case, since
* other cpus will pull from us when ready.
*/
goto out;
}
if (!task)
/* No more tasks, just exit */
goto out;
/*
* Something has shifted, try again.
*/
put_task_struct(next_task);
next_task = task;
goto retry;
}
deactivate_task(rq, next_task, 0);
next_task->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(next_task, lowest_rq->cpu);
next_task->on_rq = TASK_ON_RQ_QUEUED;
activate_task(lowest_rq, next_task, 0);
ret = 1;
resched_curr(lowest_rq);
double_unlock_balance(rq, lowest_rq);
out:
put_task_struct(next_task);
return ret;
}
static void push_rt_tasks(struct rq *rq)
{
/* push_rt_task will return true if it moved an RT */
while (push_rt_task(rq))
;
}
#ifdef HAVE_RT_PUSH_IPI
/*
* When a high priority task schedules out from a CPU and a lower priority
* task is scheduled in, a check is made to see if there's any RT tasks
* on other CPUs that are waiting to run because a higher priority RT task
* is currently running on its CPU. In this case, the CPU with multiple RT
* tasks queued on it (overloaded) needs to be notified that a CPU has opened
* up that may be able to run one of its non-running queued RT tasks.
*
* All CPUs with overloaded RT tasks need to be notified as there is currently
* no way to know which of these CPUs have the highest priority task waiting
* to run. Instead of trying to take a spinlock on each of these CPUs,
* which has shown to cause large latency when done on machines with many
* CPUs, sending an IPI to the CPUs to have them push off the overloaded
* RT tasks waiting to run.
*
* Just sending an IPI to each of the CPUs is also an issue, as on large
* count CPU machines, this can cause an IPI storm on a CPU, especially
* if its the only CPU with multiple RT tasks queued, and a large number
* of CPUs scheduling a lower priority task at the same time.
*
* Each root domain has its own irq work function that can iterate over
* all CPUs with RT overloaded tasks. Since all CPUs with overloaded RT
* tassk must be checked if there's one or many CPUs that are lowering
* their priority, there's a single irq work iterator that will try to
* push off RT tasks that are waiting to run.
*
* When a CPU schedules a lower priority task, it will kick off the
* irq work iterator that will jump to each CPU with overloaded RT tasks.
* As it only takes the first CPU that schedules a lower priority task
* to start the process, the rto_start variable is incremented and if
* the atomic result is one, then that CPU will try to take the rto_lock.
* This prevents high contention on the lock as the process handles all
* CPUs scheduling lower priority tasks.
*
* All CPUs that are scheduling a lower priority task will increment the
* rt_loop_next variable. This will make sure that the irq work iterator
* checks all RT overloaded CPUs whenever a CPU schedules a new lower
* priority task, even if the iterator is in the middle of a scan. Incrementing
* the rt_loop_next will cause the iterator to perform another scan.
*
*/
static int rto_next_cpu(struct root_domain *rd)
{
int next;
int cpu;
/*
* When starting the IPI RT pushing, the rto_cpu is set to -1,
* rt_next_cpu() will simply return the first CPU found in
* the rto_mask.
*
* If rto_next_cpu() is called with rto_cpu is a valid cpu, it
* will return the next CPU found in the rto_mask.
*
* If there are no more CPUs left in the rto_mask, then a check is made
* against rto_loop and rto_loop_next. rto_loop is only updated with
* the rto_lock held, but any CPU may increment the rto_loop_next
* without any locking.
*/
for (;;) {
/* When rto_cpu is -1 this acts like cpumask_first() */
cpu = cpumask_next(rd->rto_cpu, rd->rto_mask);
rd->rto_cpu = cpu;
if (cpu < nr_cpu_ids)
return cpu;
rd->rto_cpu = -1;
/*
* ACQUIRE ensures we see the @rto_mask changes
* made prior to the @next value observed.
*
* Matches WMB in rt_set_overload().
*/
next = atomic_read_acquire(&rd->rto_loop_next);
if (rd->rto_loop == next)
break;
rd->rto_loop = next;
}
return -1;
}
static inline bool rto_start_trylock(atomic_t *v)
{
return !atomic_cmpxchg_acquire(v, 0, 1);
}
static inline void rto_start_unlock(atomic_t *v)
{
atomic_set_release(v, 0);
}
static void tell_cpu_to_push(struct rq *rq)
{
int cpu = -1;
/* Keep the loop going if the IPI is currently active */
atomic_inc(&rq->rd->rto_loop_next);
/* Only one CPU can initiate a loop at a time */
if (!rto_start_trylock(&rq->rd->rto_loop_start))
return;
raw_spin_lock(&rq->rd->rto_lock);
/*
* The rto_cpu is updated under the lock, if it has a valid cpu
* then the IPI is still running and will continue due to the
* update to loop_next, and nothing needs to be done here.
* Otherwise it is finishing up and an ipi needs to be sent.
*/
if (rq->rd->rto_cpu < 0)
cpu = rto_next_cpu(rq->rd);
raw_spin_unlock(&rq->rd->rto_lock);
rto_start_unlock(&rq->rd->rto_loop_start);
if (cpu >= 0) {
/* Make sure the rd does not get freed while pushing */
sched_get_rd(rq->rd);
irq_work_queue_on(&rq->rd->rto_push_work, cpu);
}
}
/* Called from hardirq context */
void rto_push_irq_work_func(struct irq_work *work)
{
struct root_domain *rd =
container_of(work, struct root_domain, rto_push_work);
struct rq *rq;
int cpu;
rq = this_rq();
/*
* We do not need to grab the lock to check for has_pushable_tasks.
* When it gets updated, a check is made if a push is possible.
*/
if (has_pushable_tasks(rq)) {
raw_spin_lock(&rq->lock);
push_rt_tasks(rq);
raw_spin_unlock(&rq->lock);
}
raw_spin_lock(&rd->rto_lock);
/* Pass the IPI to the next rt overloaded queue */
cpu = rto_next_cpu(rd);
raw_spin_unlock(&rd->rto_lock);
if (cpu < 0) {
sched_put_rd(rd);
return;
}
/* Try the next RT overloaded CPU */
irq_work_queue_on(&rd->rto_push_work, cpu);
}
#endif /* HAVE_RT_PUSH_IPI */
static void pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, cpu;
bool resched = false;
struct task_struct *p;
struct rq *src_rq;
int rt_overload_count = rt_overloaded(this_rq);
if (likely(!rt_overload_count))
return;
/*
* Match the barrier from rt_set_overloaded; this guarantees that if we
* see overloaded we must also see the rto_mask bit.
*/
smp_rmb();
/* If we are the only overloaded CPU do nothing */
if (rt_overload_count == 1 &&
cpumask_test_cpu(this_rq->cpu, this_rq->rd->rto_mask))
return;
#ifdef HAVE_RT_PUSH_IPI
if (sched_feat(RT_PUSH_IPI)) {
tell_cpu_to_push(this_rq);
return;
}
#endif
for_each_cpu(cpu, this_rq->rd->rto_mask) {
if (this_cpu == cpu)
continue;
src_rq = cpu_rq(cpu);
/*
* Don't bother taking the src_rq->lock if the next highest
* task is known to be lower-priority than our current task.
* This may look racy, but if this value is about to go
* logically higher, the src_rq will push this task away.
* And if its going logically lower, we do not care
*/
if (src_rq->rt.highest_prio.next >=
this_rq->rt.highest_prio.curr)
continue;
/*
* We can potentially drop this_rq's lock in
* double_lock_balance, and another CPU could
* alter this_rq
*/
double_lock_balance(this_rq, src_rq);
/*
* We can pull only a task, which is pushable
* on its rq, and no others.
*/
p = pick_highest_pushable_task(src_rq, this_cpu);
/*
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!task_on_rq_queued(p));
/*
* There's a chance that p is higher in priority
* than what's currently running on its cpu.
* This is just that p is wakeing up and hasn't
* had a chance to schedule. We only pull
* p if it is lower in priority than the
* current task on the run queue
*/
if (p->prio < src_rq->curr->prio)
goto skip;
resched = true;
deactivate_task(src_rq, p, 0);
p->on_rq = TASK_ON_RQ_MIGRATING;
set_task_cpu(p, this_cpu);
p->on_rq = TASK_ON_RQ_QUEUED;
activate_task(this_rq, p, 0);
/*
* We continue with the search, just in
* case there's an even higher prio task
* in another runqueue. (low likelihood
* but possible)
*/
}
skip:
double_unlock_balance(this_rq, src_rq);
}
if (resched)
resched_curr(this_rq);
}
/*
* If we are not running and we are not going to reschedule soon, we should
* try to push tasks away now
*/
static void task_woken_rt(struct rq *rq, struct task_struct *p)
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
p->nr_cpus_allowed > 1 &&
(dl_task(rq->curr) || rt_task(rq->curr)) &&
(rq->curr->nr_cpus_allowed < 2 ||
rq->curr->prio <= p->prio)) {
#ifdef CONFIG_SCHED_USE_FLUID_RT
if (p->rt.sync_flag && rq->curr->prio < p->prio) {
p->rt.sync_flag = 0;
push_rt_tasks(rq);
}
#else
push_rt_tasks(rq);
#endif
}
#ifdef CONFIG_SCHED_USE_FLUID_RT
p->rt.sync_flag = 0;
#endif
}
/* Assumes rq->lock is held */
static void rq_online_rt(struct rq *rq)
{
if (rq->rt.overloaded)
rt_set_overload(rq);
__enable_runtime(rq);
cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
}
/* Assumes rq->lock is held */
static void rq_offline_rt(struct rq *rq)
{
if (rq->rt.overloaded)
rt_clear_overload(rq);
__disable_runtime(rq);
cpupri_set(&rq->rd->cpupri, rq->cpu, CPUPRI_INVALID);
}
/*
* When switch from the rt queue, we bring ourselves to a position
* that we might want to pull RT tasks from other runqueues.
*/
static void switched_from_rt(struct rq *rq, struct task_struct *p)
{
#ifdef CONFIG_RT_GROUP_SCHED
detach_task_rt_rq(p);
#endif
/*
* If there are other RT tasks then we will reschedule
* and the scheduling of the other RT tasks will handle
* the balancing. But if we are the last RT task
* we may need to handle the pulling of RT tasks
* now.
*/
if (!task_on_rq_queued(p) || rq->rt.rt_nr_running)
return;
queue_pull_task(rq);
}
void __init init_sched_rt_class(void)
{
unsigned int i;
for_each_possible_cpu(i) {
zalloc_cpumask_var_node(&per_cpu(local_cpu_mask, i),
GFP_KERNEL, cpu_to_node(i));
}
}
#else
void update_rt_load_avg(u64 now, struct sched_rt_entity *rt_se)
{
}
#endif /* CONFIG_SMP */
extern void
copy_sched_avg(struct sched_avg *from, struct sched_avg *to, unsigned int ratio);
/*
* When switching a task to RT, we may overload the runqueue
* with RT tasks. In this case we try to push them off to
* other runqueues.
*/
static void switched_to_rt(struct rq *rq, struct task_struct *p)
{
/* Copy fair sched avg into rt sched avg */
copy_sched_avg(&p->se.avg, &p->rt.avg, 100);
/*
* If we are already running, then there's nothing
* that needs to be done. But if we are not running
* we may need to preempt the current running task.
* If that current running task is also an RT task
* then see if we can move to another run queue.
*/
if (task_on_rq_queued(p) && rq->curr != p) {
#ifdef CONFIG_SMP
if (p->nr_cpus_allowed > 1 && rq->rt.overloaded)
queue_push_tasks(rq);
#endif /* CONFIG_SMP */
if (p->prio < rq->curr->prio && cpu_online(cpu_of(rq)))
resched_curr(rq);
}
}
/*
* Priority of the task has changed. This may cause
* us to initiate a push or pull.
*/
static void
prio_changed_rt(struct rq *rq, struct task_struct *p, int oldprio)
{
if (!task_on_rq_queued(p))
return;
if (rq->curr == p) {
#ifdef CONFIG_SMP
/*
* If our priority decreases while running, we
* may need to pull tasks to this runqueue.
*/
if (oldprio < p->prio)
queue_pull_task(rq);
/*
* If there's a higher priority task waiting to run
* then reschedule.
*/
if (p->prio > rq->rt.highest_prio.curr)
resched_curr(rq);
#else
/* For UP simply resched on drop of prio */
if (oldprio < p->prio)
resched_curr(rq);
#endif /* CONFIG_SMP */
} else {
/*
* This task is not running, but if it is
* greater than the current running task
* then reschedule.
*/
if (p->prio < rq->curr->prio)
resched_curr(rq);
}
}
#ifdef CONFIG_POSIX_TIMERS
static void watchdog(struct rq *rq, struct task_struct *p)
{
unsigned long soft, hard;
/* max may change after cur was read, this will be fixed next tick */
soft = task_rlimit(p, RLIMIT_RTTIME);
hard = task_rlimit_max(p, RLIMIT_RTTIME);
if (soft != RLIM_INFINITY) {
unsigned long next;
if (p->rt.watchdog_stamp != jiffies) {
p->rt.timeout++;
p->rt.watchdog_stamp = jiffies;
}
next = DIV_ROUND_UP(min(soft, hard), USEC_PER_SEC/HZ);
if (p->rt.timeout > next)
p->cputime_expires.sched_exp = p->se.sum_exec_runtime;
}
}
#else
static inline void watchdog(struct rq *rq, struct task_struct *p) { }
#endif
static void task_tick_rt(struct rq *rq, struct task_struct *p, int queued)
{
struct sched_rt_entity *rt_se = &p->rt;
u64 now = rq_clock_task(rq);
int cpu = cpu_of(rq);
update_curr_rt(rq);
for_each_sched_rt_entity(rt_se)
update_rt_load_avg(now, rt_se);
update_rt_rq_load_avg(now, cpu, &rq->rt, rq->curr != NULL);
update_activated_cpus();
watchdog(rq, p);
/*
* RR tasks need a special form of timeslice management.
* FIFO tasks have no timeslices.
*/
if (p->policy != SCHED_RR)
return;
if (--p->rt.time_slice)
return;
p->rt.time_slice = sched_rr_timeslice;
/*
* Requeue to the end of queue if we (and all of our ancestors) are not
* the only element on the queue
*/
for_each_sched_rt_entity(rt_se) {
if (rt_se->run_list.prev != rt_se->run_list.next) {
requeue_task_rt(rq, p, 0);
resched_curr(rq);
return;
}
}
}
static void set_curr_task_rt(struct rq *rq)
{
struct task_struct *p = rq->curr;
struct sched_rt_entity *rt_se = &p->rt;
p->se.exec_start = rq_clock_task(rq);
for_each_sched_rt_entity(rt_se) {
struct rt_rq *rt_rq = rt_rq_of_se(rt_se);
rt_rq->curr = rt_se;
}
/* The running task is never eligible for pushing */
dequeue_pushable_task(rq, p);
}
static unsigned int get_rr_interval_rt(struct rq *rq, struct task_struct *task)
{
/*
* Time slice is 0 for SCHED_FIFO tasks
*/
if (task->policy == SCHED_RR)
return sched_rr_timeslice;
else
return 0;
}
const struct sched_class rt_sched_class = {
.next = &fair_sched_class,
.enqueue_task = enqueue_task_rt,
.dequeue_task = dequeue_task_rt,
.yield_task = yield_task_rt,
.check_preempt_curr = check_preempt_curr_rt,
.pick_next_task = pick_next_task_rt,
.put_prev_task = put_prev_task_rt,
#ifdef CONFIG_SMP
.select_task_rq = select_task_rq_rt,
.migrate_task_rq = migrate_task_rq_rt,
.task_dead = task_dead_rt,
.set_cpus_allowed = set_cpus_allowed_common,
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.task_woken = task_woken_rt,
.switched_from = switched_from_rt,
#endif
.set_curr_task = set_curr_task_rt,
.task_tick = task_tick_rt,
.get_rr_interval = get_rr_interval_rt,
.prio_changed = prio_changed_rt,
.switched_to = switched_to_rt,
.update_curr = update_curr_rt,
#ifdef CONFIG_SCHED_WALT
.fixup_cumulative_runnable_avg = walt_fixup_cumulative_runnable_avg,
#endif
#ifdef CONFIG_RT_GROUP_SCHED
.task_change_group = task_change_group_rt,
#endif
};
#ifdef CONFIG_RT_GROUP_SCHED
/*
* Ensure that the real time constraints are schedulable.
*/
static DEFINE_MUTEX(rt_constraints_mutex);
/* Must be called with tasklist_lock held */
static inline int tg_has_rt_tasks(struct task_group *tg)
{
struct task_struct *g, *p;
/*
* Autogroups do not have RT tasks; see autogroup_create().
*/
if (task_group_is_autogroup(tg))
return 0;
for_each_process_thread(g, p) {
if (rt_task(p) && task_group(p) == tg)
return 1;
}
return 0;
}
struct rt_schedulable_data {
struct task_group *tg;
u64 rt_period;
u64 rt_runtime;
};
static int tg_rt_schedulable(struct task_group *tg, void *data)
{
struct rt_schedulable_data *d = data;
struct task_group *child;
unsigned long total, sum = 0;
u64 period, runtime;
period = ktime_to_ns(tg->rt_bandwidth.rt_period);
runtime = tg->rt_bandwidth.rt_runtime;
if (tg == d->tg) {
period = d->rt_period;
runtime = d->rt_runtime;
}
/*
* Cannot have more runtime than the period.
*/
if (runtime > period && runtime != RUNTIME_INF)
return -EINVAL;
/*
* Ensure we don't starve existing RT tasks.
*/
if (rt_bandwidth_enabled() && !runtime && tg_has_rt_tasks(tg))
return -EBUSY;
total = to_ratio(period, runtime);
/*
* Nobody can have more than the global setting allows.
*/
if (total > to_ratio(global_rt_period(), global_rt_runtime()))
return -EINVAL;
/*
* The sum of our children's runtime should not exceed our own.
*/
list_for_each_entry_rcu(child, &tg->children, siblings) {
period = ktime_to_ns(child->rt_bandwidth.rt_period);
runtime = child->rt_bandwidth.rt_runtime;
if (child == d->tg) {
period = d->rt_period;
runtime = d->rt_runtime;
}
sum += to_ratio(period, runtime);
}
if (sum > total)
return -EINVAL;
return 0;
}
static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime)
{
int ret;
struct rt_schedulable_data data = {
.tg = tg,
.rt_period = period,
.rt_runtime = runtime,
};
rcu_read_lock();
ret = walk_tg_tree(tg_rt_schedulable, tg_nop, &data);
rcu_read_unlock();
return ret;
}
static int tg_set_rt_bandwidth(struct task_group *tg,
u64 rt_period, u64 rt_runtime)
{
int i, err = 0;
/*
* Disallowing the root group RT runtime is BAD, it would disallow the
* kernel creating (and or operating) RT threads.
*/
if (tg == &root_task_group && rt_runtime == 0)
return -EINVAL;
/* No period doesn't make any sense. */
if (rt_period == 0)
return -EINVAL;
mutex_lock(&rt_constraints_mutex);
read_lock(&tasklist_lock);
err = __rt_schedulable(tg, rt_period, rt_runtime);
if (err)
goto unlock;
raw_spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock);
tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period);
tg->rt_bandwidth.rt_runtime = rt_runtime;
for_each_possible_cpu(i) {
struct rt_rq *rt_rq = tg->rt_rq[i];
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_runtime = rt_runtime;
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
raw_spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock);
unlock:
read_unlock(&tasklist_lock);
mutex_unlock(&rt_constraints_mutex);
return err;
}
int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us)
{
u64 rt_runtime, rt_period;
rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period);
rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC;
if (rt_runtime_us < 0)
rt_runtime = RUNTIME_INF;
else if ((u64)rt_runtime_us > U64_MAX / NSEC_PER_USEC)
return -EINVAL;
return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
}
long sched_group_rt_runtime(struct task_group *tg)
{
u64 rt_runtime_us;
if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF)
return -1;
rt_runtime_us = tg->rt_bandwidth.rt_runtime;
do_div(rt_runtime_us, NSEC_PER_USEC);
return rt_runtime_us;
}
int sched_group_set_rt_period(struct task_group *tg, u64 rt_period_us)
{
u64 rt_runtime, rt_period;
if (rt_period_us > U64_MAX / NSEC_PER_USEC)
return -EINVAL;
rt_period = rt_period_us * NSEC_PER_USEC;
rt_runtime = tg->rt_bandwidth.rt_runtime;
return tg_set_rt_bandwidth(tg, rt_period, rt_runtime);
}
long sched_group_rt_period(struct task_group *tg)
{
u64 rt_period_us;
rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period);
do_div(rt_period_us, NSEC_PER_USEC);
return rt_period_us;
}
static int sched_rt_global_constraints(void)
{
int ret = 0;
mutex_lock(&rt_constraints_mutex);
read_lock(&tasklist_lock);
ret = __rt_schedulable(NULL, 0, 0);
read_unlock(&tasklist_lock);
mutex_unlock(&rt_constraints_mutex);
return ret;
}
int sched_rt_can_attach(struct task_group *tg, struct task_struct *tsk)
{
/* Don't accept realtime tasks when there is no way for them to run */
if (rt_task(tsk) && tg->rt_bandwidth.rt_runtime == 0)
return 0;
return 1;
}
#else /* !CONFIG_RT_GROUP_SCHED */
static int sched_rt_global_constraints(void)
{
unsigned long flags;
int i;
raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
for_each_possible_cpu(i) {
struct rt_rq *rt_rq = &cpu_rq(i)->rt;
raw_spin_lock(&rt_rq->rt_runtime_lock);
rt_rq->rt_runtime = global_rt_runtime();
raw_spin_unlock(&rt_rq->rt_runtime_lock);
}
raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
return 0;
}
#endif /* CONFIG_RT_GROUP_SCHED */
static int sched_rt_global_validate(void)
{
if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
(sysctl_sched_rt_runtime > sysctl_sched_rt_period))
return -EINVAL;
return 0;
}
static void sched_rt_do_global(void)
{
unsigned long flags;
raw_spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags);
def_rt_bandwidth.rt_runtime = global_rt_runtime();
def_rt_bandwidth.rt_period = ns_to_ktime(global_rt_period());
raw_spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags);
}
int sched_rt_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int old_period, old_runtime;
static DEFINE_MUTEX(mutex);
int ret;
mutex_lock(&mutex);
old_period = sysctl_sched_rt_period;
old_runtime = sysctl_sched_rt_runtime;
ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
if (!ret && write) {
ret = sched_rt_global_validate();
if (ret)
goto undo;
ret = sched_dl_global_validate();
if (ret)
goto undo;
ret = sched_rt_global_constraints();
if (ret)
goto undo;
sched_rt_do_global();
sched_dl_do_global();
}
if (0) {
undo:
sysctl_sched_rt_period = old_period;
sysctl_sched_rt_runtime = old_runtime;
}
mutex_unlock(&mutex);
return ret;
}
int sched_rr_handler(struct ctl_table *table, int write,
void __user *buffer, size_t *lenp,
loff_t *ppos)
{
int ret;
static DEFINE_MUTEX(mutex);
mutex_lock(&mutex);
ret = proc_dointvec(table, write, buffer, lenp, ppos);
/*
* Make sure that internally we keep jiffies.
* Also, writing zero resets the timeslice to default:
*/
if (!ret && write) {
sched_rr_timeslice =
sysctl_sched_rr_timeslice <= 0 ? RR_TIMESLICE :
msecs_to_jiffies(sysctl_sched_rr_timeslice);
if (sysctl_sched_rr_timeslice <= 0)
sysctl_sched_rr_timeslice = jiffies_to_msecs(RR_TIMESLICE);
}
mutex_unlock(&mutex);
return ret;
}
#ifdef CONFIG_SCHED_DEBUG
void print_rt_stats(struct seq_file *m, int cpu)
{
rt_rq_iter_t iter;
struct rt_rq *rt_rq;
rcu_read_lock();
for_each_rt_rq(rt_rq, iter, cpu_rq(cpu))
print_rt_rq(m, cpu, rt_rq);
rcu_read_unlock();
}
#endif /* CONFIG_SCHED_DEBUG */