{
ktime_t now;
- if (rt_bandwidth_enabled() && rt_b->rt_runtime == RUNTIME_INF)
+ if (!rt_bandwidth_enabled() || rt_b->rt_runtime == RUNTIME_INF)
return;
if (hrtimer_active(&rt_b->rt_period_timer))
spin_lock(&rt_b->rt_runtime_lock);
for (;;) {
+ unsigned long delta;
+ ktime_t soft, hard;
+
if (hrtimer_active(&rt_b->rt_period_timer))
break;
now = hrtimer_cb_get_time(&rt_b->rt_period_timer);
hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period);
- hrtimer_start_expires(&rt_b->rt_period_timer,
- HRTIMER_MODE_ABS);
+
+ soft = hrtimer_get_softexpires(&rt_b->rt_period_timer);
+ hard = hrtimer_get_expires(&rt_b->rt_period_timer);
+ delta = ktime_to_ns(ktime_sub(hard, soft));
+ __hrtimer_start_range_ns(&rt_b->rt_period_timer, soft, delta,
+ HRTIMER_MODE_ABS, 0);
}
spin_unlock(&rt_b->rt_runtime_lock);
}
*/
static DEFINE_SPINLOCK(task_group_lock);
+ #ifdef CONFIG_SMP
+ static int root_task_group_empty(void)
+ {
+ return list_empty(&root_task_group.children);
+ }
+ #endif
+
#ifdef CONFIG_FAIR_GROUP_SCHED
#ifdef CONFIG_USER_SCHED
# define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD)
#else
+ #ifdef CONFIG_SMP
+ static int root_task_group_empty(void)
+ {
+ return 1;
+ }
+ #endif
+
static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { }
static inline struct task_group *task_group(struct task_struct *p)
{
struct rt_prio_array active;
unsigned long rt_nr_running;
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
- int highest_prio; /* highest queued rt task prio */
+ struct {
+ int curr; /* highest queued rt task prio */
+ #ifdef CONFIG_SMP
+ int next; /* next highest */
+ #endif
+ } highest_prio;
#endif
#ifdef CONFIG_SMP
unsigned long rt_nr_migratory;
int overloaded;
+ struct plist_head pushable_tasks;
#endif
int rt_throttled;
u64 rt_time;
unsigned long nr_running;
#define CPU_LOAD_IDX_MAX 5
unsigned long cpu_load[CPU_LOAD_IDX_MAX];
- unsigned char idle_at_tick;
#ifdef CONFIG_NO_HZ
unsigned long last_tick_seen;
unsigned char in_nohz_recently;
struct root_domain *rd;
struct sched_domain *sd;
+ unsigned char idle_at_tick;
/* For active balancing */
int active_balance;
int push_cpu;
/* could above be rq->cfs_rq.exec_clock + rq->rt_rq.rt_runtime ? */
/* sys_sched_yield() stats */
- unsigned int yld_exp_empty;
- unsigned int yld_act_empty;
- unsigned int yld_both_empty;
unsigned int yld_count;
/* schedule() stats */
if (rq == this_rq()) {
hrtimer_restart(timer);
} else if (!rq->hrtick_csd_pending) {
- __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd);
+ __smp_call_function_single(cpu_of(rq), &rq->hrtick_csd, 0);
rq->hrtick_csd_pending = 1;
}
}
*/
static void hrtick_start(struct rq *rq, u64 delay)
{
- hrtimer_start(&rq->hrtick_timer, ns_to_ktime(delay), HRTIMER_MODE_REL);
+ __hrtimer_start_range_ns(&rq->hrtick_timer, ns_to_ktime(delay), 0,
+ HRTIMER_MODE_REL, 0);
}
static inline void init_hrtick(void)
assert_spin_locked(&task_rq(p)->lock);
- if (unlikely(test_tsk_thread_flag(p, TIF_NEED_RESCHED)))
+ if (test_tsk_need_resched(p))
return;
- set_tsk_thread_flag(p, TIF_NEED_RESCHED);
+ set_tsk_need_resched(p);
cpu = task_cpu(p);
if (cpu == smp_processor_id())
* lockless. The worst case is that the other CPU runs the
* idle task through an additional NOOP schedule()
*/
- set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED);
+ set_tsk_need_resched(rq->idle);
/* NEED_RESCHED must be visible before we test polling */
smp_mb();
struct rq_iterator *iterator);
#endif
+/* Time spent by the tasks of the cpu accounting group executing in ... */
+enum cpuacct_stat_index {
+ CPUACCT_STAT_USER, /* ... user mode */
+ CPUACCT_STAT_SYSTEM, /* ... kernel mode */
+
+ CPUACCT_STAT_NSTATS,
+};
+
#ifdef CONFIG_CGROUP_CPUACCT
static void cpuacct_charge(struct task_struct *tsk, u64 cputime);
+static void cpuacct_update_stats(struct task_struct *tsk,
+ enum cpuacct_stat_index idx, cputime_t val);
#else
static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {}
+static inline void cpuacct_update_stats(struct task_struct *tsk,
+ enum cpuacct_stat_index idx, cputime_t val) {}
#endif
static inline void inc_cpu_load(struct rq *rq, unsigned long load)
#endif
+ #ifdef CONFIG_PREEMPT
+
/*
- * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ * fair double_lock_balance: Safely acquires both rq->locks in a fair
+ * way at the expense of forcing extra atomic operations in all
+ * invocations. This assures that the double_lock is acquired using the
+ * same underlying policy as the spinlock_t on this architecture, which
+ * reduces latency compared to the unfair variant below. However, it
+ * also adds more overhead and therefore may reduce throughput.
*/
- static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+ static inline int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
+ __releases(this_rq->lock)
+ __acquires(busiest->lock)
+ __acquires(this_rq->lock)
+ {
+ spin_unlock(&this_rq->lock);
+ double_rq_lock(this_rq, busiest);
+
+ return 1;
+ }
+
+ #else
+ /*
+ * Unfair double_lock_balance: Optimizes throughput at the expense of
+ * latency by eliminating extra atomic operations when the locks are
+ * already in proper order on entry. This favors lower cpu-ids and will
+ * grant the double lock to lower cpus over higher ids under contention,
+ * regardless of entry order into the function.
+ */
+ static int _double_lock_balance(struct rq *this_rq, struct rq *busiest)
__releases(this_rq->lock)
__acquires(busiest->lock)
__acquires(this_rq->lock)
{
int ret = 0;
- if (unlikely(!irqs_disabled())) {
- /* printk() doesn't work good under rq->lock */
- spin_unlock(&this_rq->lock);
- BUG_ON(1);
- }
if (unlikely(!spin_trylock(&busiest->lock))) {
if (busiest < this_rq) {
spin_unlock(&this_rq->lock);
return ret;
}
+ #endif /* CONFIG_PREEMPT */
+
+ /*
+ * double_lock_balance - lock the busiest runqueue, this_rq is locked already.
+ */
+ static int double_lock_balance(struct rq *this_rq, struct rq *busiest)
+ {
+ if (unlikely(!irqs_disabled())) {
+ /* printk() doesn't work good under rq->lock */
+ spin_unlock(&this_rq->lock);
+ BUG_ON(1);
+ }
+
+ return _double_lock_balance(this_rq, busiest);
+ }
+
static inline void double_unlock_balance(struct rq *this_rq, struct rq *busiest)
__releases(busiest->lock)
{
static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup)
{
+ if (wakeup)
+ p->se.start_runtime = p->se.sum_exec_runtime;
+
sched_info_queued(p);
p->sched_class->enqueue_task(rq, p, wakeup);
p->se.on_rq = 1;
static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep)
{
- if (sleep && p->se.last_wakeup) {
- update_avg(&p->se.avg_overlap,
- p->se.sum_exec_runtime - p->se.last_wakeup);
- p->se.last_wakeup = 0;
+ if (sleep) {
+ if (p->se.last_wakeup) {
+ update_avg(&p->se.avg_overlap,
+ p->se.sum_exec_runtime - p->se.last_wakeup);
+ p->se.last_wakeup = 0;
+ } else {
+ update_avg(&p->se.avg_wakeup,
+ sysctl_sched_wakeup_granularity);
+ }
}
sched_info_dequeued(p);
* it must be off the runqueue _entirely_, and not
* preempted!
*
- * So if it wa still runnable (but just not actively
+ * So if it was still runnable (but just not actively
* running right now), it's preempted, and we should
* yield - it could be a while.
*/
if (!sched_feat(SYNC_WAKEUPS))
sync = 0;
- if (!sync) {
- if (current->se.avg_overlap < sysctl_sched_migration_cost &&
- p->se.avg_overlap < sysctl_sched_migration_cost)
- sync = 1;
- } else {
- if (current->se.avg_overlap >= sysctl_sched_migration_cost ||
- p->se.avg_overlap >= sysctl_sched_migration_cost)
- sync = 0;
- }
-
#ifdef CONFIG_SMP
- if (sched_feat(LB_WAKEUP_UPDATE)) {
+ if (sched_feat(LB_WAKEUP_UPDATE) && !root_task_group_empty()) {
struct sched_domain *sd;
this_cpu = raw_smp_processor_id();
activate_task(rq, p, 1);
success = 1;
+ /*
+ * Only attribute actual wakeups done by this task.
+ */
+ if (!in_interrupt()) {
+ struct sched_entity *se = ¤t->se;
+ u64 sample = se->sum_exec_runtime;
+
+ if (se->last_wakeup)
+ sample -= se->last_wakeup;
+ else
+ sample -= se->start_runtime;
+ update_avg(&se->avg_wakeup, sample);
+
+ se->last_wakeup = se->sum_exec_runtime;
+ }
+
out_running:
trace_sched_wakeup(rq, p, success);
check_preempt_curr(rq, p, sync);
p->sched_class->task_wake_up(rq, p);
#endif
out:
- current->se.last_wakeup = current->se.sum_exec_runtime;
-
task_rq_unlock(rq, &flags);
return success;
p->se.prev_sum_exec_runtime = 0;
p->se.last_wakeup = 0;
p->se.avg_overlap = 0;
+ p->se.start_runtime = 0;
+ p->se.avg_wakeup = sysctl_sched_wakeup_granularity;
#ifdef CONFIG_SCHEDSTATS
p->se.wait_start = 0;
/* Want to start with kernel preemption disabled. */
task_thread_info(p)->preempt_count = 1;
#endif
+ plist_node_init(&p->pushable_tasks, MAX_PRIO);
+
put_cpu();
}
#ifdef CONFIG_PREEMPT_NOTIFIERS
/**
- * preempt_notifier_register - tell me when current is being being preempted & rescheduled
+ * preempt_notifier_register - tell me when current is being preempted & rescheduled
* @notifier: notifier struct to register
*/
void preempt_notifier_register(struct preempt_notifier *notifier)
{
struct mm_struct *mm = rq->prev_mm;
long prev_state;
+ #ifdef CONFIG_SMP
+ int post_schedule = 0;
+
+ if (current->sched_class->needs_post_schedule)
+ post_schedule = current->sched_class->needs_post_schedule(rq);
+ #endif
rq->prev_mm = NULL;
finish_arch_switch(prev);
finish_lock_switch(rq, prev);
#ifdef CONFIG_SMP
- if (current->sched_class->post_schedule)
+ if (post_schedule)
current->sched_class->post_schedule(rq);
#endif
struct sched_domain *sd, enum cpu_idle_type idle,
int *all_pinned)
{
+ int tsk_cache_hot = 0;
/*
* We do not migrate tasks that are:
* 1) running (obviously), or
* 2) too many balance attempts have failed.
*/
- if (!task_hot(p, rq->clock, sd) ||
- sd->nr_balance_failed > sd->cache_nice_tries) {
+ tsk_cache_hot = task_hot(p, rq->clock, sd);
+ if (!tsk_cache_hot ||
+ sd->nr_balance_failed > sd->cache_nice_tries) {
#ifdef CONFIG_SCHEDSTATS
- if (task_hot(p, rq->clock, sd)) {
+ if (tsk_cache_hot) {
schedstat_inc(sd, lb_hot_gained[idle]);
schedstat_inc(p, se.nr_forced_migrations);
}
return 1;
}
- if (task_hot(p, rq->clock, sd)) {
+ if (tsk_cache_hot) {
schedstat_inc(p, se.nr_failed_migrations_hot);
return 0;
}
pulled++;
rem_load_move -= p->se.load.weight;
+ #ifdef CONFIG_PREEMPT
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible kernels
+ * will stop after the first task is pulled to minimize the critical
+ * section.
+ */
+ if (idle == CPU_NEWLY_IDLE)
+ goto out;
+ #endif
+
/*
* We only want to steal up to the prescribed amount of weighted load.
*/
sd, idle, all_pinned, &this_best_prio);
class = class->next;
+ #ifdef CONFIG_PREEMPT
+ /*
+ * NEWIDLE balancing is a source of latency, so preemptible
+ * kernels will stop after the first task is pulled to minimize
+ * the critical section.
+ */
if (idle == CPU_NEWLY_IDLE && this_rq->nr_running)
break;
-
+ #endif
} while (class && max_load_move > total_load_moved);
return total_load_moved > 0;
return 0;
}
-
+ /********** Helpers for find_busiest_group ************************/
/*
- * find_busiest_group finds and returns the busiest CPU group within the
- * domain. It calculates and returns the amount of weighted load which
- * should be moved to restore balance via the imbalance parameter.
+ * sd_lb_stats - Structure to store the statistics of a sched_domain
+ * during load balancing.
*/
- static struct sched_group *
- find_busiest_group(struct sched_domain *sd, int this_cpu,
- unsigned long *imbalance, enum cpu_idle_type idle,
- int *sd_idle, const struct cpumask *cpus, int *balance)
- {
- struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups;
- unsigned long max_load, avg_load, total_load, this_load, total_pwr;
- unsigned long max_pull;
- unsigned long busiest_load_per_task, busiest_nr_running;
- unsigned long this_load_per_task, this_nr_running;
- int load_idx, group_imb = 0;
+ struct sd_lb_stats {
+ struct sched_group *busiest; /* Busiest group in this sd */
+ struct sched_group *this; /* Local group in this sd */
+ unsigned long total_load; /* Total load of all groups in sd */
+ unsigned long total_pwr; /* Total power of all groups in sd */
+ unsigned long avg_load; /* Average load across all groups in sd */
+
+ /** Statistics of this group */
+ unsigned long this_load;
+ unsigned long this_load_per_task;
+ unsigned long this_nr_running;
+
+ /* Statistics of the busiest group */
+ unsigned long max_load;
+ unsigned long busiest_load_per_task;
+ unsigned long busiest_nr_running;
+
+ int group_imb; /* Is there imbalance in this sd */
#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- int power_savings_balance = 1;
- unsigned long leader_nr_running = 0, min_load_per_task = 0;
- unsigned long min_nr_running = ULONG_MAX;
- struct sched_group *group_min = NULL, *group_leader = NULL;
+ int power_savings_balance; /* Is powersave balance needed for this sd */
+ struct sched_group *group_min; /* Least loaded group in sd */
+ struct sched_group *group_leader; /* Group which relieves group_min */
+ unsigned long min_load_per_task; /* load_per_task in group_min */
+ unsigned long leader_nr_running; /* Nr running of group_leader */
+ unsigned long min_nr_running; /* Nr running of group_min */
#endif
+ };
- max_load = this_load = total_load = total_pwr = 0;
- busiest_load_per_task = busiest_nr_running = 0;
- this_load_per_task = this_nr_running = 0;
+ /*
+ * sg_lb_stats - stats of a sched_group required for load_balancing
+ */
+ struct sg_lb_stats {
+ unsigned long avg_load; /*Avg load across the CPUs of the group */
+ unsigned long group_load; /* Total load over the CPUs of the group */
+ unsigned long sum_nr_running; /* Nr tasks running in the group */
+ unsigned long sum_weighted_load; /* Weighted load of group's tasks */
+ unsigned long group_capacity;
+ int group_imb; /* Is there an imbalance in the group ? */
+ };
- if (idle == CPU_NOT_IDLE)
+ /**
+ * group_first_cpu - Returns the first cpu in the cpumask of a sched_group.
+ * @group: The group whose first cpu is to be returned.
+ */
+ static inline unsigned int group_first_cpu(struct sched_group *group)
+ {
+ return cpumask_first(sched_group_cpus(group));
+ }
+
+ /**
+ * get_sd_load_idx - Obtain the load index for a given sched domain.
+ * @sd: The sched_domain whose load_idx is to be obtained.
+ * @idle: The Idle status of the CPU for whose sd load_icx is obtained.
+ */
+ static inline int get_sd_load_idx(struct sched_domain *sd,
+ enum cpu_idle_type idle)
+ {
+ int load_idx;
+
+ switch (idle) {
+ case CPU_NOT_IDLE:
load_idx = sd->busy_idx;
- else if (idle == CPU_NEWLY_IDLE)
+ break;
+
+ case CPU_NEWLY_IDLE:
load_idx = sd->newidle_idx;
- else
+ break;
+ default:
load_idx = sd->idle_idx;
+ break;
+ }
- do {
- unsigned long load, group_capacity, max_cpu_load, min_cpu_load;
- int local_group;
- int i;
- int __group_imb = 0;
- unsigned int balance_cpu = -1, first_idle_cpu = 0;
- unsigned long sum_nr_running, sum_weighted_load;
- unsigned long sum_avg_load_per_task;
- unsigned long avg_load_per_task;
+ return load_idx;
+ }
- local_group = cpumask_test_cpu(this_cpu,
- sched_group_cpus(group));
- if (local_group)
- balance_cpu = cpumask_first(sched_group_cpus(group));
+ #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
+ /**
+ * init_sd_power_savings_stats - Initialize power savings statistics for
+ * the given sched_domain, during load balancing.
+ *
+ * @sd: Sched domain whose power-savings statistics are to be initialized.
+ * @sds: Variable containing the statistics for sd.
+ * @idle: Idle status of the CPU at which we're performing load-balancing.
+ */
+ static inline void init_sd_power_savings_stats(struct sched_domain *sd,
+ struct sd_lb_stats *sds, enum cpu_idle_type idle)
+ {
+ /*
+ * Busy processors will not participate in power savings
+ * balance.
+ */
+ if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
+ sds->power_savings_balance = 0;
+ else {
+ sds->power_savings_balance = 1;
+ sds->min_nr_running = ULONG_MAX;
+ sds->leader_nr_running = 0;
+ }
+ }
- /* Tally up the load of all CPUs in the group */
- sum_weighted_load = sum_nr_running = avg_load = 0;
- sum_avg_load_per_task = avg_load_per_task = 0;
+ /**
+ * update_sd_power_savings_stats - Update the power saving stats for a
+ * sched_domain while performing load balancing.
+ *
+ * @group: sched_group belonging to the sched_domain under consideration.
+ * @sds: Variable containing the statistics of the sched_domain
+ * @local_group: Does group contain the CPU for which we're performing
+ * load balancing ?
+ * @sgs: Variable containing the statistics of the group.
+ */
+ static inline void update_sd_power_savings_stats(struct sched_group *group,
+ struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
+ {
- max_cpu_load = 0;
- min_cpu_load = ~0UL;
+ if (!sds->power_savings_balance)
+ return;
- for_each_cpu_and(i, sched_group_cpus(group), cpus) {
- struct rq *rq = cpu_rq(i);
+ /*
+ * If the local group is idle or completely loaded
+ * no need to do power savings balance at this domain
+ */
+ if (local_group && (sds->this_nr_running >= sgs->group_capacity ||
+ !sds->this_nr_running))
+ sds->power_savings_balance = 0;
- if (*sd_idle && rq->nr_running)
- *sd_idle = 0;
+ /*
+ * If a group is already running at full capacity or idle,
+ * don't include that group in power savings calculations
+ */
+ if (!sds->power_savings_balance ||
+ sgs->sum_nr_running >= sgs->group_capacity ||
+ !sgs->sum_nr_running)
+ return;
- /* Bias balancing toward cpus of our domain */
- if (local_group) {
- if (idle_cpu(i) && !first_idle_cpu) {
- first_idle_cpu = 1;
- balance_cpu = i;
- }
+ /*
+ * Calculate the group which has the least non-idle load.
+ * This is the group from where we need to pick up the load
+ * for saving power
+ */
+ if ((sgs->sum_nr_running < sds->min_nr_running) ||
+ (sgs->sum_nr_running == sds->min_nr_running &&
+ group_first_cpu(group) > group_first_cpu(sds->group_min))) {
+ sds->group_min = group;
+ sds->min_nr_running = sgs->sum_nr_running;
+ sds->min_load_per_task = sgs->sum_weighted_load /
+ sgs->sum_nr_running;
+ }
- load = target_load(i, load_idx);
- } else {
- load = source_load(i, load_idx);
- if (load > max_cpu_load)
- max_cpu_load = load;
- if (min_cpu_load > load)
- min_cpu_load = load;
- }
+ /*
+ * Calculate the group which is almost near its
+ * capacity but still has some space to pick up some load
+ * from other group and save more power
+ */
+ if (sgs->sum_nr_running > sgs->group_capacity - 1)
+ return;
- avg_load += load;
- sum_nr_running += rq->nr_running;
- sum_weighted_load += weighted_cpuload(i);
+ if (sgs->sum_nr_running > sds->leader_nr_running ||
+ (sgs->sum_nr_running == sds->leader_nr_running &&
+ group_first_cpu(group) < group_first_cpu(sds->group_leader))) {
+ sds->group_leader = group;
+ sds->leader_nr_running = sgs->sum_nr_running;
+ }
+ }
- sum_avg_load_per_task += cpu_avg_load_per_task(i);
- }
+ /**
+ * check_power_save_busiest_group - see if there is potential for some power-savings balance
+ * @sds: Variable containing the statistics of the sched_domain
+ * under consideration.
+ * @this_cpu: Cpu at which we're currently performing load-balancing.
+ * @imbalance: Variable to store the imbalance.
+ *
+ * Description:
+ * Check if we have potential to perform some power-savings balance.
+ * If yes, set the busiest group to be the least loaded group in the
+ * sched_domain, so that it's CPUs can be put to idle.
+ *
+ * Returns 1 if there is potential to perform power-savings balance.
+ * Else returns 0.
+ */
+ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+ {
+ if (!sds->power_savings_balance)
+ return 0;
- /*
- * First idle cpu or the first cpu(busiest) in this sched group
- * is eligible for doing load balancing at this and above
- * domains. In the newly idle case, we will allow all the cpu's
- * to do the newly idle load balance.
- */
- if (idle != CPU_NEWLY_IDLE && local_group &&
- balance_cpu != this_cpu && balance) {
- *balance = 0;
- goto ret;
- }
+ if (sds->this != sds->group_leader ||
+ sds->group_leader == sds->group_min)
+ return 0;
- total_load += avg_load;
- total_pwr += group->__cpu_power;
+ *imbalance = sds->min_load_per_task;
+ sds->busiest = sds->group_min;
- /* Adjust by relative CPU power of the group */
- avg_load = sg_div_cpu_power(group,
- avg_load * SCHED_LOAD_SCALE);
+ if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
+ cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
+ group_first_cpu(sds->group_leader);
+ }
+
+ return 1;
+ }
+ #else /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+ static inline void init_sd_power_savings_stats(struct sched_domain *sd,
+ struct sd_lb_stats *sds, enum cpu_idle_type idle)
+ {
+ return;
+ }
- /*
- * Consider the group unbalanced when the imbalance is larger
- * than the average weight of two tasks.
- *
- * APZ: with cgroup the avg task weight can vary wildly and
- * might not be a suitable number - should we keep a
- * normalized nr_running number somewhere that negates
- * the hierarchy?
- */
- avg_load_per_task = sg_div_cpu_power(group,
- sum_avg_load_per_task * SCHED_LOAD_SCALE);
+ static inline void update_sd_power_savings_stats(struct sched_group *group,
+ struct sd_lb_stats *sds, int local_group, struct sg_lb_stats *sgs)
+ {
+ return;
+ }
+
+ static inline int check_power_save_busiest_group(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+ {
+ return 0;
+ }
+ #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */
+
+
+ /**
+ * update_sg_lb_stats - Update sched_group's statistics for load balancing.
+ * @group: sched_group whose statistics are to be updated.
+ * @this_cpu: Cpu for which load balance is currently performed.
+ * @idle: Idle status of this_cpu
+ * @load_idx: Load index of sched_domain of this_cpu for load calc.
+ * @sd_idle: Idle status of the sched_domain containing group.
+ * @local_group: Does group contain this_cpu.
+ * @cpus: Set of cpus considered for load balancing.
+ * @balance: Should we balance.
+ * @sgs: variable to hold the statistics for this group.
+ */
+ static inline void update_sg_lb_stats(struct sched_group *group, int this_cpu,
+ enum cpu_idle_type idle, int load_idx, int *sd_idle,
+ int local_group, const struct cpumask *cpus,
+ int *balance, struct sg_lb_stats *sgs)
+ {
+ unsigned long load, max_cpu_load, min_cpu_load;
+ int i;
+ unsigned int balance_cpu = -1, first_idle_cpu = 0;
+ unsigned long sum_avg_load_per_task;
+ unsigned long avg_load_per_task;
+
+ if (local_group)
+ balance_cpu = group_first_cpu(group);
+
+ /* Tally up the load of all CPUs in the group */
+ sum_avg_load_per_task = avg_load_per_task = 0;
+ max_cpu_load = 0;
+ min_cpu_load = ~0UL;
- if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
- __group_imb = 1;
+ for_each_cpu_and(i, sched_group_cpus(group), cpus) {
+ struct rq *rq = cpu_rq(i);
- group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
+ if (*sd_idle && rq->nr_running)
+ *sd_idle = 0;
+ /* Bias balancing toward cpus of our domain */
if (local_group) {
- this_load = avg_load;
- this = group;
- this_nr_running = sum_nr_running;
- this_load_per_task = sum_weighted_load;
- } else if (avg_load > max_load &&
- (sum_nr_running > group_capacity || __group_imb)) {
- max_load = avg_load;
- busiest = group;
- busiest_nr_running = sum_nr_running;
- busiest_load_per_task = sum_weighted_load;
- group_imb = __group_imb;
+ if (idle_cpu(i) && !first_idle_cpu) {
+ first_idle_cpu = 1;
+ balance_cpu = i;
+ }
+
+ load = target_load(i, load_idx);
+ } else {
+ load = source_load(i, load_idx);
+ if (load > max_cpu_load)
+ max_cpu_load = load;
+ if (min_cpu_load > load)
+ min_cpu_load = load;
}
- #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- /*
- * Busy processors will not participate in power savings
- * balance.
- */
- if (idle == CPU_NOT_IDLE ||
- !(sd->flags & SD_POWERSAVINGS_BALANCE))
- goto group_next;
+ sgs->group_load += load;
+ sgs->sum_nr_running += rq->nr_running;
+ sgs->sum_weighted_load += weighted_cpuload(i);
- /*
- * If the local group is idle or completely loaded
- * no need to do power savings balance at this domain
- */
- if (local_group && (this_nr_running >= group_capacity ||
- !this_nr_running))
- power_savings_balance = 0;
+ sum_avg_load_per_task += cpu_avg_load_per_task(i);
+ }
- /*
- * If a group is already running at full capacity or idle,
- * don't include that group in power savings calculations
- */
- if (!power_savings_balance || sum_nr_running >= group_capacity
- || !sum_nr_running)
- goto group_next;
+ /*
+ * First idle cpu or the first cpu(busiest) in this sched group
+ * is eligible for doing load balancing at this and above
+ * domains. In the newly idle case, we will allow all the cpu's
+ * to do the newly idle load balance.
+ */
+ if (idle != CPU_NEWLY_IDLE && local_group &&
+ balance_cpu != this_cpu && balance) {
+ *balance = 0;
+ return;
+ }
- /*
- * Calculate the group which has the least non-idle load.
- * This is the group from where we need to pick up the load
- * for saving power
- */
- if ((sum_nr_running < min_nr_running) ||
- (sum_nr_running == min_nr_running &&
- cpumask_first(sched_group_cpus(group)) >
- cpumask_first(sched_group_cpus(group_min)))) {
- group_min = group;
- min_nr_running = sum_nr_running;
- min_load_per_task = sum_weighted_load /
- sum_nr_running;
- }
+ /* Adjust by relative CPU power of the group */
+ sgs->avg_load = sg_div_cpu_power(group,
+ sgs->group_load * SCHED_LOAD_SCALE);
- /*
- * Calculate the group which is almost near its
- * capacity but still has some space to pick up some load
- * from other group and save more power
- */
- if (sum_nr_running <= group_capacity - 1) {
- if (sum_nr_running > leader_nr_running ||
- (sum_nr_running == leader_nr_running &&
- cpumask_first(sched_group_cpus(group)) <
- cpumask_first(sched_group_cpus(group_leader)))) {
- group_leader = group;
- leader_nr_running = sum_nr_running;
- }
+
+ /*
+ * Consider the group unbalanced when the imbalance is larger
+ * than the average weight of two tasks.
+ *
+ * APZ: with cgroup the avg task weight can vary wildly and
+ * might not be a suitable number - should we keep a
+ * normalized nr_running number somewhere that negates
+ * the hierarchy?
+ */
+ avg_load_per_task = sg_div_cpu_power(group,
+ sum_avg_load_per_task * SCHED_LOAD_SCALE);
+
+ if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task)
+ sgs->group_imb = 1;
+
+ sgs->group_capacity = group->__cpu_power / SCHED_LOAD_SCALE;
+
+ }
+
+ /**
+ * update_sd_lb_stats - Update sched_group's statistics for load balancing.
+ * @sd: sched_domain whose statistics are to be updated.
+ * @this_cpu: Cpu for which load balance is currently performed.
+ * @idle: Idle status of this_cpu
+ * @sd_idle: Idle status of the sched_domain containing group.
+ * @cpus: Set of cpus considered for load balancing.
+ * @balance: Should we balance.
+ * @sds: variable to hold the statistics for this sched_domain.
+ */
+ static inline void update_sd_lb_stats(struct sched_domain *sd, int this_cpu,
+ enum cpu_idle_type idle, int *sd_idle,
+ const struct cpumask *cpus, int *balance,
+ struct sd_lb_stats *sds)
+ {
+ struct sched_group *group = sd->groups;
+ struct sg_lb_stats sgs;
+ int load_idx;
+
+ init_sd_power_savings_stats(sd, sds, idle);
+ load_idx = get_sd_load_idx(sd, idle);
+
+ do {
+ int local_group;
+
+ local_group = cpumask_test_cpu(this_cpu,
+ sched_group_cpus(group));
+ memset(&sgs, 0, sizeof(sgs));
+ update_sg_lb_stats(group, this_cpu, idle, load_idx, sd_idle,
+ local_group, cpus, balance, &sgs);
+
+ if (local_group && balance && !(*balance))
+ return;
+
+ sds->total_load += sgs.group_load;
+ sds->total_pwr += group->__cpu_power;
+
+ if (local_group) {
+ sds->this_load = sgs.avg_load;
+ sds->this = group;
+ sds->this_nr_running = sgs.sum_nr_running;
+ sds->this_load_per_task = sgs.sum_weighted_load;
+ } else if (sgs.avg_load > sds->max_load &&
+ (sgs.sum_nr_running > sgs.group_capacity ||
+ sgs.group_imb)) {
+ sds->max_load = sgs.avg_load;
+ sds->busiest = group;
+ sds->busiest_nr_running = sgs.sum_nr_running;
+ sds->busiest_load_per_task = sgs.sum_weighted_load;
+ sds->group_imb = sgs.group_imb;
}
- group_next:
- #endif
+
+ update_sd_power_savings_stats(group, sds, local_group, &sgs);
group = group->next;
} while (group != sd->groups);
- if (!busiest || this_load >= max_load || busiest_nr_running == 0)
- goto out_balanced;
-
- avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr;
+ }
- if (this_load >= avg_load ||
- 100*max_load <= sd->imbalance_pct*this_load)
- goto out_balanced;
+ /**
+ * fix_small_imbalance - Calculate the minor imbalance that exists
+ * amongst the groups of a sched_domain, during
+ * load balancing.
+ * @sds: Statistics of the sched_domain whose imbalance is to be calculated.
+ * @this_cpu: The cpu at whose sched_domain we're performing load-balance.
+ * @imbalance: Variable to store the imbalance.
+ */
+ static inline void fix_small_imbalance(struct sd_lb_stats *sds,
+ int this_cpu, unsigned long *imbalance)
+ {
+ unsigned long tmp, pwr_now = 0, pwr_move = 0;
+ unsigned int imbn = 2;
+
+ if (sds->this_nr_running) {
+ sds->this_load_per_task /= sds->this_nr_running;
+ if (sds->busiest_load_per_task >
+ sds->this_load_per_task)
+ imbn = 1;
+ } else
+ sds->this_load_per_task =
+ cpu_avg_load_per_task(this_cpu);
- busiest_load_per_task /= busiest_nr_running;
- if (group_imb)
- busiest_load_per_task = min(busiest_load_per_task, avg_load);
+ if (sds->max_load - sds->this_load + sds->busiest_load_per_task >=
+ sds->busiest_load_per_task * imbn) {
+ *imbalance = sds->busiest_load_per_task;
+ return;
+ }
/*
- * We're trying to get all the cpus to the average_load, so we don't
- * want to push ourselves above the average load, nor do we wish to
- * reduce the max loaded cpu below the average load, as either of these
- * actions would just result in more rebalancing later, and ping-pong
- * tasks around. Thus we look for the minimum possible imbalance.
- * Negative imbalances (*we* are more loaded than anyone else) will
- * be counted as no imbalance for these purposes -- we can't fix that
- * by pulling tasks to us. Be careful of negative numbers as they'll
- * appear as very large values with unsigned longs.
+ * OK, we don't have enough imbalance to justify moving tasks,
+ * however we may be able to increase total CPU power used by
+ * moving them.
*/
- if (max_load <= busiest_load_per_task)
- goto out_balanced;
+ pwr_now += sds->busiest->__cpu_power *
+ min(sds->busiest_load_per_task, sds->max_load);
+ pwr_now += sds->this->__cpu_power *
+ min(sds->this_load_per_task, sds->this_load);
+ pwr_now /= SCHED_LOAD_SCALE;
+
+ /* Amount of load we'd subtract */
+ tmp = sg_div_cpu_power(sds->busiest,
+ sds->busiest_load_per_task * SCHED_LOAD_SCALE);
+ if (sds->max_load > tmp)
+ pwr_move += sds->busiest->__cpu_power *
+ min(sds->busiest_load_per_task, sds->max_load - tmp);
+
+ /* Amount of load we'd add */
+ if (sds->max_load * sds->busiest->__cpu_power <
+ sds->busiest_load_per_task * SCHED_LOAD_SCALE)
+ tmp = sg_div_cpu_power(sds->this,
+ sds->max_load * sds->busiest->__cpu_power);
+ else
+ tmp = sg_div_cpu_power(sds->this,
+ sds->busiest_load_per_task * SCHED_LOAD_SCALE);
+ pwr_move += sds->this->__cpu_power *
+ min(sds->this_load_per_task, sds->this_load + tmp);
+ pwr_move /= SCHED_LOAD_SCALE;
+
+ /* Move if we gain throughput */
+ if (pwr_move > pwr_now)
+ *imbalance = sds->busiest_load_per_task;
+ }
+
+ /**
+ * calculate_imbalance - Calculate the amount of imbalance present within the
+ * groups of a given sched_domain during load balance.
+ * @sds: statistics of the sched_domain whose imbalance is to be calculated.
+ * @this_cpu: Cpu for which currently load balance is being performed.
+ * @imbalance: The variable to store the imbalance.
+ */
+ static inline void calculate_imbalance(struct sd_lb_stats *sds, int this_cpu,
+ unsigned long *imbalance)
+ {
+ unsigned long max_pull;
/*
* In the presence of smp nice balancing, certain scenarios can have
* max load less than avg load(as we skip the groups at or below
* its cpu_power, while calculating max_load..)
*/
- if (max_load < avg_load) {
+ if (sds->max_load < sds->avg_load) {
*imbalance = 0;
- goto small_imbalance;
+ return fix_small_imbalance(sds, this_cpu, imbalance);
}
/* Don't want to pull so many tasks that a group would go idle */
- max_pull = min(max_load - avg_load, max_load - busiest_load_per_task);
+ max_pull = min(sds->max_load - sds->avg_load,
+ sds->max_load - sds->busiest_load_per_task);
/* How much load to actually move to equalise the imbalance */
- *imbalance = min(max_pull * busiest->__cpu_power,
- (avg_load - this_load) * this->__cpu_power)
+ *imbalance = min(max_pull * sds->busiest->__cpu_power,
+ (sds->avg_load - sds->this_load) * sds->this->__cpu_power)
/ SCHED_LOAD_SCALE;
/*
* a think about bumping its value to force at least one task to be
* moved
*/
- if (*imbalance < busiest_load_per_task) {
- unsigned long tmp, pwr_now, pwr_move;
- unsigned int imbn;
-
- small_imbalance:
- pwr_move = pwr_now = 0;
- imbn = 2;
- if (this_nr_running) {
- this_load_per_task /= this_nr_running;
- if (busiest_load_per_task > this_load_per_task)
- imbn = 1;
- } else
- this_load_per_task = cpu_avg_load_per_task(this_cpu);
+ if (*imbalance < sds->busiest_load_per_task)
+ return fix_small_imbalance(sds, this_cpu, imbalance);
- if (max_load - this_load + busiest_load_per_task >=
- busiest_load_per_task * imbn) {
- *imbalance = busiest_load_per_task;
- return busiest;
- }
+ }
+ /******* find_busiest_group() helpers end here *********************/
- /*
- * OK, we don't have enough imbalance to justify moving tasks,
- * however we may be able to increase total CPU power used by
- * moving them.
- */
+ /**
+ * find_busiest_group - Returns the busiest group within the sched_domain
+ * if there is an imbalance. If there isn't an imbalance, and
+ * the user has opted for power-savings, it returns a group whose
+ * CPUs can be put to idle by rebalancing those tasks elsewhere, if
+ * such a group exists.
+ *
+ * Also calculates the amount of weighted load which should be moved
+ * to restore balance.
+ *
+ * @sd: The sched_domain whose busiest group is to be returned.
+ * @this_cpu: The cpu for which load balancing is currently being performed.
+ * @imbalance: Variable which stores amount of weighted load which should
+ * be moved to restore balance/put a group to idle.
+ * @idle: The idle status of this_cpu.
+ * @sd_idle: The idleness of sd
+ * @cpus: The set of CPUs under consideration for load-balancing.
+ * @balance: Pointer to a variable indicating if this_cpu
+ * is the appropriate cpu to perform load balancing at this_level.
+ *
+ * Returns: - the busiest group if imbalance exists.
+ * - If no imbalance and user has opted for power-savings balance,
+ * return the least loaded group whose CPUs can be
+ * put to idle by rebalancing its tasks onto our group.
+ */
+ static struct sched_group *
+ find_busiest_group(struct sched_domain *sd, int this_cpu,
+ unsigned long *imbalance, enum cpu_idle_type idle,
+ int *sd_idle, const struct cpumask *cpus, int *balance)
+ {
+ struct sd_lb_stats sds;
- pwr_now += busiest->__cpu_power *
- min(busiest_load_per_task, max_load);
- pwr_now += this->__cpu_power *
- min(this_load_per_task, this_load);
- pwr_now /= SCHED_LOAD_SCALE;
-
- /* Amount of load we'd subtract */
- tmp = sg_div_cpu_power(busiest,
- busiest_load_per_task * SCHED_LOAD_SCALE);
- if (max_load > tmp)
- pwr_move += busiest->__cpu_power *
- min(busiest_load_per_task, max_load - tmp);
-
- /* Amount of load we'd add */
- if (max_load * busiest->__cpu_power <
- busiest_load_per_task * SCHED_LOAD_SCALE)
- tmp = sg_div_cpu_power(this,
- max_load * busiest->__cpu_power);
- else
- tmp = sg_div_cpu_power(this,
- busiest_load_per_task * SCHED_LOAD_SCALE);
- pwr_move += this->__cpu_power *
- min(this_load_per_task, this_load + tmp);
- pwr_move /= SCHED_LOAD_SCALE;
+ memset(&sds, 0, sizeof(sds));
- /* Move if we gain throughput */
- if (pwr_move > pwr_now)
- *imbalance = busiest_load_per_task;
- }
+ /*
+ * Compute the various statistics relavent for load balancing at
+ * this level.
+ */
+ update_sd_lb_stats(sd, this_cpu, idle, sd_idle, cpus,
+ balance, &sds);
+
+ /* Cases where imbalance does not exist from POV of this_cpu */
+ /* 1) this_cpu is not the appropriate cpu to perform load balancing
+ * at this level.
+ * 2) There is no busy sibling group to pull from.
+ * 3) This group is the busiest group.
+ * 4) This group is more busy than the avg busieness at this
+ * sched_domain.
+ * 5) The imbalance is within the specified limit.
+ * 6) Any rebalance would lead to ping-pong
+ */
+ if (balance && !(*balance))
+ goto ret;
- return busiest;
+ if (!sds.busiest || sds.busiest_nr_running == 0)
+ goto out_balanced;
- out_balanced:
- #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
- if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE))
- goto ret;
+ if (sds.this_load >= sds.max_load)
+ goto out_balanced;
- if (this == group_leader && group_leader != group_min) {
- *imbalance = min_load_per_task;
- if (sched_mc_power_savings >= POWERSAVINGS_BALANCE_WAKEUP) {
- cpu_rq(this_cpu)->rd->sched_mc_preferred_wakeup_cpu =
- cpumask_first(sched_group_cpus(group_leader));
- }
- return group_min;
- }
- #endif
+ sds.avg_load = (SCHED_LOAD_SCALE * sds.total_load) / sds.total_pwr;
+
+ if (sds.this_load >= sds.avg_load)
+ goto out_balanced;
+
+ if (100 * sds.max_load <= sd->imbalance_pct * sds.this_load)
+ goto out_balanced;
+
+ sds.busiest_load_per_task /= sds.busiest_nr_running;
+ if (sds.group_imb)
+ sds.busiest_load_per_task =
+ min(sds.busiest_load_per_task, sds.avg_load);
+
+ /*
+ * We're trying to get all the cpus to the average_load, so we don't
+ * want to push ourselves above the average load, nor do we wish to
+ * reduce the max loaded cpu below the average load, as either of these
+ * actions would just result in more rebalancing later, and ping-pong
+ * tasks around. Thus we look for the minimum possible imbalance.
+ * Negative imbalances (*we* are more loaded than anyone else) will
+ * be counted as no imbalance for these purposes -- we can't fix that
+ * by pulling tasks to us. Be careful of negative numbers as they'll
+ * appear as very large values with unsigned longs.
+ */
+ if (sds.max_load <= sds.busiest_load_per_task)
+ goto out_balanced;
+
+ /* Looks like there is an imbalance. Compute it */
+ calculate_imbalance(&sds, this_cpu, imbalance);
+ return sds.busiest;
+
+ out_balanced:
+ /*
+ * There is no obvious imbalance. But check if we can do some balancing
+ * to save power.
+ */
+ if (check_power_save_busiest_group(&sds, this_cpu, imbalance))
+ return sds.busiest;
ret:
*imbalance = 0;
return NULL;
*/
#define MAX_PINNED_INTERVAL 512
+ /* Working cpumask for load_balance and load_balance_newidle. */
+ static DEFINE_PER_CPU(cpumask_var_t, load_balance_tmpmask);
+
/*
* Check this_cpu to ensure it is balanced within domain. Attempt to move
* tasks if there is an imbalance.
*/
static int load_balance(int this_cpu, struct rq *this_rq,
struct sched_domain *sd, enum cpu_idle_type idle,
- int *balance, struct cpumask *cpus)
+ int *balance)
{
int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0;
struct sched_group *group;
unsigned long imbalance;
struct rq *busiest;
unsigned long flags;
+ struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
cpumask_setall(cpus);
* this_rq is locked.
*/
static int
- load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd,
- struct cpumask *cpus)
+ load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd)
{
struct sched_group *group;
struct rq *busiest = NULL;
int ld_moved = 0;
int sd_idle = 0;
int all_pinned = 0;
+ struct cpumask *cpus = __get_cpu_var(load_balance_tmpmask);
cpumask_setall(cpus);
struct sched_domain *sd;
int pulled_task = 0;
unsigned long next_balance = jiffies + HZ;
- cpumask_var_t tmpmask;
-
- if (!alloc_cpumask_var(&tmpmask, GFP_ATOMIC))
- return;
for_each_domain(this_cpu, sd) {
unsigned long interval;
if (sd->flags & SD_BALANCE_NEWIDLE)
/* If we've pulled tasks over stop searching: */
pulled_task = load_balance_newidle(this_cpu, this_rq,
- sd, tmpmask);
+ sd);
interval = msecs_to_jiffies(sd->balance_interval);
if (time_after(next_balance, sd->last_balance + interval))
*/
this_rq->next_balance = next_balance;
}
- free_cpumask_var(tmpmask);
}
/*
int cpu = smp_processor_id();
if (stop_tick) {
- cpumask_set_cpu(cpu, nohz.cpu_mask);
cpu_rq(cpu)->in_nohz_recently = 1;
- /*
- * If we are going offline and still the leader, give up!
- */
- if (!cpu_active(cpu) &&
- atomic_read(&nohz.load_balancer) == cpu) {
+ if (!cpu_active(cpu)) {
+ if (atomic_read(&nohz.load_balancer) != cpu)
+ return 0;
+
+ /*
+ * If we are going offline and still the leader,
+ * give up!
+ */
if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu)
BUG();
+
return 0;
}
+ cpumask_set_cpu(cpu, nohz.cpu_mask);
+
/* time for ilb owner also to sleep */
if (cpumask_weight(nohz.cpu_mask) == num_online_cpus()) {
if (atomic_read(&nohz.load_balancer) == cpu)
unsigned long next_balance = jiffies + 60*HZ;
int update_next_balance = 0;
int need_serialize;
- cpumask_var_t tmp;
-
- /* Fails alloc? Rebalancing probably not a priority right now. */
- if (!alloc_cpumask_var(&tmp, GFP_ATOMIC))
- return;
for_each_domain(cpu, sd) {
if (!(sd->flags & SD_LOAD_BALANCE))
}
if (time_after_eq(jiffies, sd->last_balance + interval)) {
- if (load_balance(cpu, rq, sd, idle, &balance, tmp)) {
+ if (load_balance(cpu, rq, sd, idle, &balance)) {
/*
* We've pulled tasks over so either we're no
* longer idle, or one of our SMT siblings is
*/
if (likely(update_next_balance))
rq->next_balance = next_balance;
-
- free_cpumask_var(tmp);
}
/*
#endif
}
+ static inline int on_null_domain(int cpu)
+ {
+ return !rcu_dereference(cpu_rq(cpu)->sd);
+ }
+
/*
* Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
*
cpumask_test_cpu(cpu, nohz.cpu_mask))
return;
#endif
- if (time_after_eq(jiffies, rq->next_balance))
+ /* Don't need to rebalance while attached to NULL domain */
+ if (time_after_eq(jiffies, rq->next_balance) &&
+ likely(!on_null_domain(cpu)))
raise_softirq(SCHED_SOFTIRQ);
}
EXPORT_PER_CPU_SYMBOL(kstat);
/*
- * Return any ns on the sched_clock that have not yet been banked in
+ * Return any ns on the sched_clock that have not yet been accounted in
* @p in case that task is currently running.
+ *
+ * Called with task_rq_lock() held on @rq.
*/
+static u64 do_task_delta_exec(struct task_struct *p, struct rq *rq)
+{
+ u64 ns = 0;
+
+ if (task_current(rq, p)) {
+ update_rq_clock(rq);
+ ns = rq->clock - p->se.exec_start;
+ if ((s64)ns < 0)
+ ns = 0;
+ }
+
+ return ns;
+}
+
unsigned long long task_delta_exec(struct task_struct *p)
{
unsigned long flags;
u64 ns = 0;
rq = task_rq_lock(p, &flags);
+ ns = do_task_delta_exec(p, rq);
+ task_rq_unlock(rq, &flags);
- if (task_current(rq, p)) {
- u64 delta_exec;
+ return ns;
+}
- update_rq_clock(rq);
- delta_exec = rq->clock - p->se.exec_start;
- if ((s64)delta_exec > 0)
- ns = delta_exec;
- }
+/*
+ * Return accounted runtime for the task.
+ * In case the task is currently running, return the runtime plus current's
+ * pending runtime that have not been accounted yet.
+ */
+unsigned long long task_sched_runtime(struct task_struct *p)
+{
+ unsigned long flags;
+ struct rq *rq;
+ u64 ns = 0;
+
+ rq = task_rq_lock(p, &flags);
+ ns = p->se.sum_exec_runtime + do_task_delta_exec(p, rq);
+ task_rq_unlock(rq, &flags);
+
+ return ns;
+}
+
+/*
+ * Return sum_exec_runtime for the thread group.
+ * In case the task is currently running, return the sum plus current's
+ * pending runtime that have not been accounted yet.
+ *
+ * Note that the thread group might have other running tasks as well,
+ * so the return value not includes other pending runtime that other
+ * running tasks might have.
+ */
+unsigned long long thread_group_sched_runtime(struct task_struct *p)
+{
+ struct task_cputime totals;
+ unsigned long flags;
+ struct rq *rq;
+ u64 ns;
+ rq = task_rq_lock(p, &flags);
+ thread_group_cputime(p, &totals);
+ ns = totals.sum_exec_runtime + do_task_delta_exec(p, rq);
task_rq_unlock(rq, &flags);
return ns;
cpustat->nice = cputime64_add(cpustat->nice, tmp);
else
cpustat->user = cputime64_add(cpustat->user, tmp);
+
+ cpuacct_update_stats(p, CPUACCT_STAT_USER, cputime);
/* Account for user time used */
acct_update_integrals(p);
}
else
cpustat->system = cputime64_add(cpustat->system, tmp);
+ cpuacct_update_stats(p, CPUACCT_STAT_SYSTEM, cputime);
+
/* Account for system time used */
acct_update_integrals(p);
}
#endif
}
- #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
- defined(CONFIG_PREEMPT_TRACER))
-
- static inline unsigned long get_parent_ip(unsigned long addr)
+ unsigned long get_parent_ip(unsigned long addr)
{
if (in_lock_functions(addr)) {
addr = CALLER_ADDR2;
return addr;
}
+ #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \
+ defined(CONFIG_PREEMPT_TRACER))
+
void __kprobes add_preempt_count(int val)
{
#ifdef CONFIG_DEBUG_PREEMPT
#endif
}
+ static void put_prev_task(struct rq *rq, struct task_struct *prev)
+ {
+ if (prev->state == TASK_RUNNING) {
+ u64 runtime = prev->se.sum_exec_runtime;
+
+ runtime -= prev->se.prev_sum_exec_runtime;
+ runtime = min_t(u64, runtime, 2*sysctl_sched_migration_cost);
+
+ /*
+ * In order to avoid avg_overlap growing stale when we are
+ * indeed overlapping and hence not getting put to sleep, grow
+ * the avg_overlap on preemption.
+ *
+ * We use the average preemption runtime because that
+ * correlates to the amount of cache footprint a task can
+ * build up.
+ */
+ update_avg(&prev->se.avg_overlap, runtime);
+ }
+ prev->sched_class->put_prev_task(rq, prev);
+ }
+
/*
* Pick up the highest-prio task:
*/
static inline struct task_struct *
- pick_next_task(struct rq *rq, struct task_struct *prev)
+ pick_next_task(struct rq *rq)
{
const struct sched_class *class;
struct task_struct *p;
if (unlikely(!rq->nr_running))
idle_balance(cpu, rq);
- prev->sched_class->put_prev_task(rq, prev);
- next = pick_next_task(rq, prev);
+ put_prev_task(rq, prev);
+ next = pick_next_task(rq);
if (likely(prev != next)) {
sched_info_switch(prev, next);
* between schedule and now.
*/
barrier();
- } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+ } while (need_resched());
}
EXPORT_SYMBOL(preempt_schedule);
* between schedule and now.
*/
barrier();
- } while (unlikely(test_thread_flag(TIF_NEED_RESCHED)));
+ } while (need_resched());
}
#endif /* CONFIG_PREEMPT */
__wake_up_common(q, mode, 1, 0, NULL);
}
+ void __wake_up_locked_key(wait_queue_head_t *q, unsigned int mode, void *key)
+ {
+ __wake_up_common(q, mode, 1, 0, key);
+ }
+
/**
- * __wake_up_sync - wake up threads blocked on a waitqueue.
+ * __wake_up_sync_key - wake up threads blocked on a waitqueue.
* @q: the waitqueue
* @mode: which threads
* @nr_exclusive: how many wake-one or wake-many threads to wake up
+ * @key: opaque value to be passed to wakeup targets
*
* The sync wakeup differs that the waker knows that it will schedule
* away soon, so while the target thread will be woken up, it will not
*
* On UP it can prevent extra preemption.
*/
- void
- __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+ void __wake_up_sync_key(wait_queue_head_t *q, unsigned int mode,
+ int nr_exclusive, void *key)
{
unsigned long flags;
int sync = 1;
sync = 0;
spin_lock_irqsave(&q->lock, flags);
- __wake_up_common(q, mode, nr_exclusive, sync, NULL);
+ __wake_up_common(q, mode, nr_exclusive, sync, key);
spin_unlock_irqrestore(&q->lock, flags);
}
+ EXPORT_SYMBOL_GPL(__wake_up_sync_key);
+
+ /*
+ * __wake_up_sync - see __wake_up_sync_key()
+ */
+ void __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive)
+ {
+ __wake_up_sync_key(q, mode, nr_exclusive, NULL);
+ }
EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */
/**
if (increment > 40)
increment = 40;
- nice = PRIO_TO_NICE(current->static_prio) + increment;
+ nice = TASK_NICE(current) + increment;
if (nice < -20)
nice = -20;
if (nice > 19)
printk(KERN_CONT " %016lx ", thread_saved_pc(p));
#endif
#ifdef CONFIG_DEBUG_STACK_USAGE
- {
- unsigned long *n = end_of_stack(p);
- while (!*n)
- n++;
- free = (unsigned long)n - (unsigned long)end_of_stack(p);
- }
+ free = stack_not_used(p);
#endif
printk(KERN_CONT "%5lu %5d %6d\n", free,
task_pid_nr(p), task_pid_nr(p->real_parent));
if (!rq->nr_running)
break;
update_rq_clock(rq);
- next = pick_next_task(rq, rq->curr);
+ next = pick_next_task(rq);
if (!next)
break;
next->sched_class->put_prev_task(rq, next);
cpumask_or(groupmask, groupmask, sched_group_cpus(group));
cpulist_scnprintf(str, sizeof(str), sched_group_cpus(group));
- printk(KERN_CONT " %s", str);
+ printk(KERN_CONT " %s (__cpu_power = %d)", str,
+ group->__cpu_power);
group = group->next;
} while (group != sd->groups);
static void rq_attach_root(struct rq *rq, struct root_domain *rd)
{
+ struct root_domain *old_rd = NULL;
unsigned long flags;
spin_lock_irqsave(&rq->lock, flags);
if (rq->rd) {
- struct root_domain *old_rd = rq->rd;
+ old_rd = rq->rd;
if (cpumask_test_cpu(rq->cpu, old_rd->online))
set_rq_offline(rq);
cpumask_clear_cpu(rq->cpu, old_rd->span);
- if (atomic_dec_and_test(&old_rd->refcount))
- free_rootdomain(old_rd);
+ /*
+ * If we dont want to free the old_rt yet then
+ * set old_rd to NULL to skip the freeing later
+ * in this function:
+ */
+ if (!atomic_dec_and_test(&old_rd->refcount))
+ old_rd = NULL;
}
atomic_inc(&rd->refcount);
set_rq_online(rq);
spin_unlock_irqrestore(&rq->lock, flags);
+
+ if (old_rd)
+ free_rootdomain(old_rd);
}
static int __init_refok init_rootdomain(struct root_domain *rd, bool bootmem)
{
int group;
- cpumask_and(mask, &per_cpu(cpu_sibling_map, cpu), cpu_map);
+ cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
group = cpumask_first(mask);
if (sg)
*sg = &per_cpu(sched_group_core, group).sg;
cpumask_and(mask, cpu_coregroup_mask(cpu), cpu_map);
group = cpumask_first(mask);
#elif defined(CONFIG_SCHED_SMT)
- cpumask_and(mask, &per_cpu(cpu_sibling_map, cpu), cpu_map);
+ cpumask_and(mask, topology_thread_cpumask(cpu), cpu_map);
group = cpumask_first(mask);
#else
group = cpu;
SD_INIT(sd, SIBLING);
set_domain_attribute(sd, attr);
cpumask_and(sched_domain_span(sd),
- &per_cpu(cpu_sibling_map, i), cpu_map);
+ topology_thread_cpumask(i), cpu_map);
sd->parent = p;
p->child = sd;
cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask);
/* Set up CPU (sibling) groups */
for_each_cpu(i, cpu_map) {
cpumask_and(this_sibling_map,
- &per_cpu(cpu_sibling_map, i), cpu_map);
+ topology_thread_cpumask(i), cpu_map);
if (i != cpumask_first(this_sibling_map))
continue;
__set_bit(MAX_RT_PRIO, array->bitmap);
#if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
- rt_rq->highest_prio = MAX_RT_PRIO;
+ rt_rq->highest_prio.curr = MAX_RT_PRIO;
+ #ifdef CONFIG_SMP
+ rt_rq->highest_prio.next = MAX_RT_PRIO;
+ #endif
#endif
#ifdef CONFIG_SMP
rt_rq->rt_nr_migratory = 0;
rt_rq->overloaded = 0;
+ plist_head_init(&rq->rt.pushable_tasks, &rq->lock);
#endif
rt_rq->rt_time = 0;
#endif
#ifdef CONFIG_USER_SCHED
alloc_size *= 2;
+ #endif
+ #ifdef CONFIG_CPUMASK_OFFSTACK
+ alloc_size += num_possible_cpus() * cpumask_size();
#endif
/*
* As sched_init() is called before page_alloc is setup,
ptr += nr_cpu_ids * sizeof(void **);
#endif /* CONFIG_USER_SCHED */
#endif /* CONFIG_RT_GROUP_SCHED */
+ #ifdef CONFIG_CPUMASK_OFFSTACK
+ for_each_possible_cpu(i) {
+ per_cpu(load_balance_tmpmask, i) = (void *)ptr;
+ ptr += cpumask_size();
+ }
+ #endif /* CONFIG_CPUMASK_OFFSTACK */
}
#ifdef CONFIG_SMP
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)
{
struct task_struct *tsk)
{
#ifdef CONFIG_RT_GROUP_SCHED
- /* Don't accept realtime tasks when there is no way for them to run */
- if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0)
+ if (!sched_rt_can_attach(cgroup_tg(cgrp), tsk))
return -EINVAL;
#else
/* We don't support RT-tasks being in separate groups */
struct cgroup_subsys_state css;
/* cpuusage holds pointer to a u64-type object on every cpu */
u64 *cpuusage;
+ struct percpu_counter cpustat[CPUACCT_STAT_NSTATS];
struct cpuacct *parent;
};
struct cgroup_subsys *ss, struct cgroup *cgrp)
{
struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL);
+ int i;
if (!ca)
- return ERR_PTR(-ENOMEM);
+ goto out;
ca->cpuusage = alloc_percpu(u64);
- if (!ca->cpuusage) {
- kfree(ca);
- return ERR_PTR(-ENOMEM);
- }
+ if (!ca->cpuusage)
+ goto out_free_ca;
+
+ for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
+ if (percpu_counter_init(&ca->cpustat[i], 0))
+ goto out_free_counters;
if (cgrp->parent)
ca->parent = cgroup_ca(cgrp->parent);
return &ca->css;
+
+out_free_counters:
+ while (--i >= 0)
+ percpu_counter_destroy(&ca->cpustat[i]);
+ free_percpu(ca->cpuusage);
+out_free_ca:
+ kfree(ca);
+out:
+ return ERR_PTR(-ENOMEM);
}
/* destroy an existing cpu accounting group */
cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp)
{
struct cpuacct *ca = cgroup_ca(cgrp);
+ int i;
+ for (i = 0; i < CPUACCT_STAT_NSTATS; i++)
+ percpu_counter_destroy(&ca->cpustat[i]);
free_percpu(ca->cpuusage);
kfree(ca);
}
static u64 cpuacct_cpuusage_read(struct cpuacct *ca, int cpu)
{
- u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
+ u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
u64 data;
#ifndef CONFIG_64BIT
static void cpuacct_cpuusage_write(struct cpuacct *ca, int cpu, u64 val)
{
- u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
+ u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
#ifndef CONFIG_64BIT
/*
return 0;
}
+static const char *cpuacct_stat_desc[] = {
+ [CPUACCT_STAT_USER] = "user",
+ [CPUACCT_STAT_SYSTEM] = "system",
+};
+
+static int cpuacct_stats_show(struct cgroup *cgrp, struct cftype *cft,
+ struct cgroup_map_cb *cb)
+{
+ struct cpuacct *ca = cgroup_ca(cgrp);
+ int i;
+
+ for (i = 0; i < CPUACCT_STAT_NSTATS; i++) {
+ s64 val = percpu_counter_read(&ca->cpustat[i]);
+ val = cputime64_to_clock_t(val);
+ cb->fill(cb, cpuacct_stat_desc[i], val);
+ }
+ return 0;
+}
+
static struct cftype files[] = {
{
.name = "usage",
.name = "usage_percpu",
.read_seq_string = cpuacct_percpu_seq_read,
},
-
+ {
+ .name = "stat",
+ .read_map = cpuacct_stats_show,
+ },
};
static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp)
struct cpuacct *ca;
int cpu;
- if (!cpuacct_subsys.active)
+ if (unlikely(!cpuacct_subsys.active))
return;
cpu = task_cpu(tsk);
+
+ rcu_read_lock();
+
ca = task_ca(tsk);
for (; ca; ca = ca->parent) {
- u64 *cpuusage = percpu_ptr(ca->cpuusage, cpu);
+ u64 *cpuusage = per_cpu_ptr(ca->cpuusage, cpu);
*cpuusage += cputime;
}
+
+ rcu_read_unlock();
+}
+
+/*
+ * Charge the system/user time to the task's accounting group.
+ */
+static void cpuacct_update_stats(struct task_struct *tsk,
+ enum cpuacct_stat_index idx, cputime_t val)
+{
+ struct cpuacct *ca;
+
+ if (unlikely(!cpuacct_subsys.active))
+ return;
+
+ rcu_read_lock();
+ ca = task_ca(tsk);
+
+ do {
+ percpu_counter_add(&ca->cpustat[idx], val);
+ ca = ca->parent;
+ } while (ca);
+ rcu_read_unlock();
}
struct cgroup_subsys cpuacct_subsys = {
* policies)
*/
+ static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+ {
+ return container_of(rt_se, struct task_struct, rt);
+ }
+
+ #ifdef CONFIG_RT_GROUP_SCHED
+
+ 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;
+ }
+
+ #else /* CONFIG_RT_GROUP_SCHED */
+
+ static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
+ {
+ return container_of(rt_rq, struct rq, rt);
+ }
+
+ static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
+ {
+ struct task_struct *p = rt_task_of(rt_se);
+ struct rq *rq = task_rq(p);
+
+ return &rq->rt;
+ }
+
+ #endif /* CONFIG_RT_GROUP_SCHED */
+
#ifdef CONFIG_SMP
static inline int rt_overloaded(struct rq *rq)
cpumask_clear_cpu(rq->cpu, rq->rd->rto_mask);
}
- static void update_rt_migration(struct rq *rq)
+ static void update_rt_migration(struct rt_rq *rt_rq)
{
- if (rq->rt.rt_nr_migratory && (rq->rt.rt_nr_running > 1)) {
- if (!rq->rt.overloaded) {
- rt_set_overload(rq);
- rq->rt.overloaded = 1;
+ if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) {
+ if (!rt_rq->overloaded) {
+ rt_set_overload(rq_of_rt_rq(rt_rq));
+ rt_rq->overloaded = 1;
}
- } else if (rq->rt.overloaded) {
- rt_clear_overload(rq);
- rq->rt.overloaded = 0;
+ } else if (rt_rq->overloaded) {
+ rt_clear_overload(rq_of_rt_rq(rt_rq));
+ rt_rq->overloaded = 0;
}
}
- #endif /* CONFIG_SMP */
- static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se)
+ static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+ {
+ if (rt_se->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)
+ {
+ if (rt_se->nr_cpus_allowed > 1)
+ rt_rq->rt_nr_migratory--;
+
+ update_rt_migration(rt_rq);
+ }
+
+ 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);
+ }
+
+ static void dequeue_pushable_task(struct rq *rq, struct task_struct *p)
+ {
+ plist_del(&p->pushable_tasks, &rq->rt.pushable_tasks);
+ }
+
+ #else
+
+ static inline void enqueue_pushable_task(struct rq *rq, struct task_struct *p)
{
- return container_of(rt_se, struct task_struct, rt);
}
+ 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)
+ {
+ }
+
+ #endif /* CONFIG_SMP */
+
static inline int on_rt_rq(struct sched_rt_entity *rt_se)
{
return !list_empty(&rt_se->run_list);
#define for_each_leaf_rt_rq(rt_rq, rq) \
list_for_each_entry_rcu(rt_rq, &rq->leaf_rt_rq_list, leaf_rt_rq_list)
- 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;
- }
-
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = rt_se->parent)
if (rt_rq->rt_nr_running) {
if (rt_se && !on_rt_rq(rt_se))
enqueue_rt_entity(rt_se);
- if (rt_rq->highest_prio < curr->prio)
+ if (rt_rq->highest_prio.curr < curr->prio)
resched_task(curr);
}
}
#define for_each_leaf_rt_rq(rt_rq, rq) \
for (rt_rq = &rq->rt; rt_rq; rt_rq = NULL)
- static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq)
- {
- return container_of(rt_rq, struct rq, rt);
- }
-
- static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se)
- {
- struct task_struct *p = rt_task_of(rt_se);
- struct rq *rq = task_rq(p);
-
- return &rq->rt;
- }
-
#define for_each_sched_rt_entity(rt_se) \
for (; rt_se; rt_se = NULL)
struct rt_rq *rt_rq = group_rt_rq(rt_se);
if (rt_rq)
- return rt_rq->highest_prio;
+ return rt_rq->highest_prio.curr;
#endif
return rt_task_of(rt_se)->prio;
}
}
- static inline
- void inc_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
+ #if defined CONFIG_SMP
+
+ static struct task_struct *pick_next_highest_task_rt(struct rq *rq, int cpu);
+
+ static inline int next_prio(struct rq *rq)
{
- WARN_ON(!rt_prio(rt_se_prio(rt_se)));
- rt_rq->rt_nr_running++;
- #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED
- if (rt_se_prio(rt_se) < rt_rq->highest_prio) {
- #ifdef CONFIG_SMP
- struct rq *rq = rq_of_rt_rq(rt_rq);
- #endif
+ struct task_struct *next = pick_next_highest_task_rt(rq, rq->cpu);
+
+ if (next && rt_prio(next->prio))
+ return next->prio;
+ else
+ return MAX_RT_PRIO;
+ }
+
+ 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);
+
+ if (prio < prev_prio) {
+
+ /*
+ * If the new task is higher in priority than anything on the
+ * run-queue, we know that the previous high becomes our
+ * next-highest.
+ */
+ rt_rq->highest_prio.next = prev_prio;
- rt_rq->highest_prio = rt_se_prio(rt_se);
- #ifdef CONFIG_SMP
if (rq->online)
- cpupri_set(&rq->rd->cpupri, rq->cpu,
- rt_se_prio(rt_se));
- #endif
- }
- #endif
- #ifdef CONFIG_SMP
- if (rt_se->nr_cpus_allowed > 1) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
+ cpupri_set(&rq->rd->cpupri, rq->cpu, prio);
- rq->rt.rt_nr_migratory++;
- }
+ } else if (prio == rt_rq->highest_prio.curr)
+ /*
+ * If the next task is equal in priority to the highest on
+ * the run-queue, then we implicitly know that the next highest
+ * task cannot be any lower than current
+ */
+ rt_rq->highest_prio.next = prio;
+ else if (prio < rt_rq->highest_prio.next)
+ /*
+ * Otherwise, we need to recompute next-highest
+ */
+ rt_rq->highest_prio.next = next_prio(rq);
+ }
- update_rt_migration(rq_of_rt_rq(rt_rq));
- #endif
- #ifdef CONFIG_RT_GROUP_SCHED
- if (rt_se_boosted(rt_se))
- rt_rq->rt_nr_boosted++;
+ 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);
- if (rt_rq->tg)
- start_rt_bandwidth(&rt_rq->tg->rt_bandwidth);
- #else
- start_rt_bandwidth(&def_rt_bandwidth);
- #endif
+ if (rt_rq->rt_nr_running && (prio <= rt_rq->highest_prio.next))
+ rt_rq->highest_prio.next = next_prio(rq);
+
+ 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 dec_rt_tasks(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq)
- {
- #ifdef CONFIG_SMP
- int highest_prio = rt_rq->highest_prio;
- #endif
+ 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 */
- WARN_ON(!rt_prio(rt_se_prio(rt_se)));
- WARN_ON(!rt_rq->rt_nr_running);
- rt_rq->rt_nr_running--;
#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) {
- struct rt_prio_array *array;
- WARN_ON(rt_se_prio(rt_se) < rt_rq->highest_prio);
- if (rt_se_prio(rt_se) == rt_rq->highest_prio) {
- /* recalculate */
- array = &rt_rq->active;
- rt_rq->highest_prio =
+ 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);
- } /* otherwise leave rq->highest prio alone */
+ }
+
} else
- rt_rq->highest_prio = MAX_RT_PRIO;
- #endif
- #ifdef CONFIG_SMP
- if (rt_se->nr_cpus_allowed > 1) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
- rq->rt.rt_nr_migratory--;
- }
+ rt_rq->highest_prio.curr = MAX_RT_PRIO;
- if (rt_rq->highest_prio != highest_prio) {
- struct rq *rq = rq_of_rt_rq(rt_rq);
+ dec_rt_prio_smp(rt_rq, prio, prev_prio);
+ }
- if (rq->online)
- cpupri_set(&rq->rd->cpupri, rq->cpu,
- rt_rq->highest_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 */
- update_rt_migration(rq_of_rt_rq(rt_rq));
- #endif /* CONFIG_SMP */
#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);
- #endif
+ }
+
+ #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
+ 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++;
+
+ 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--;
+
+ dec_rt_prio(rt_rq, rt_se_prio(rt_se));
+ dec_rt_migration(rt_se, rt_rq);
+ dec_rt_group(rt_se, rt_rq);
}
static void __enqueue_rt_entity(struct sched_rt_entity *rt_se)
enqueue_rt_entity(rt_se);
+ if (!task_current(rq, p) && p->rt.nr_cpus_allowed > 1)
+ enqueue_pushable_task(rq, p);
+
inc_cpu_load(rq, p->se.load.weight);
}
update_curr_rt(rq);
dequeue_rt_entity(rt_se);
+ dequeue_pushable_task(rq, p);
+
dec_cpu_load(rq, p->se.load.weight);
}
static void check_preempt_equal_prio(struct rq *rq, struct task_struct *p)
{
- cpumask_var_t mask;
-
if (rq->curr->rt.nr_cpus_allowed == 1)
return;
- if (!alloc_cpumask_var(&mask, GFP_ATOMIC))
- return;
-
if (p->rt.nr_cpus_allowed != 1
- && cpupri_find(&rq->rd->cpupri, p, mask))
- goto free;
+ && cpupri_find(&rq->rd->cpupri, p, NULL))
+ return;
- if (!cpupri_find(&rq->rd->cpupri, rq->curr, mask))
- goto free;
+ if (!cpupri_find(&rq->rd->cpupri, rq->curr, NULL))
+ return;
/*
* There appears to be other cpus that can accept
*/
requeue_task_rt(rq, p, 1);
resched_task(rq->curr);
-free:
- free_cpumask_var(mask);
}
#endif /* CONFIG_SMP */
return next;
}
- static struct task_struct *pick_next_task_rt(struct rq *rq)
+ static struct task_struct *_pick_next_task_rt(struct rq *rq)
{
struct sched_rt_entity *rt_se;
struct task_struct *p;
p = rt_task_of(rt_se);
p->se.exec_start = rq->clock;
+
+ return p;
+ }
+
+ static struct task_struct *pick_next_task_rt(struct rq *rq)
+ {
+ struct task_struct *p = _pick_next_task_rt(rq);
+
+ /* The running task is never eligible for pushing */
+ if (p)
+ dequeue_pushable_task(rq, p);
+
return p;
}
{
update_curr_rt(rq);
p->se.exec_start = 0;
+
+ /*
+ * The previous task needs to be made eligible for pushing
+ * if it is still active
+ */
+ if (p->se.on_rq && p->rt.nr_cpus_allowed > 1)
+ enqueue_pushable_task(rq, p);
}
#ifdef CONFIG_SMP
static DEFINE_PER_CPU(cpumask_var_t, local_cpu_mask);
- static inline int pick_optimal_cpu(int this_cpu, cpumask_t *mask)
+ static inline int pick_optimal_cpu(int this_cpu,
+ const struct cpumask *mask)
{
int first;
/* "this_cpu" is cheaper to preempt than a remote processor */
- if ((this_cpu != -1) && cpu_isset(this_cpu, *mask))
+ if ((this_cpu != -1) && cpumask_test_cpu(this_cpu, mask))
return this_cpu;
first = cpumask_first(mask);
struct cpumask *lowest_mask = __get_cpu_var(local_cpu_mask);
int this_cpu = smp_processor_id();
int cpu = task_cpu(task);
+ cpumask_var_t domain_mask;
if (task->rt.nr_cpus_allowed == 1)
return -1; /* No other targets possible */
if (this_cpu == cpu)
this_cpu = -1; /* Skip this_cpu opt if the same */
- for_each_domain(cpu, sd) {
- if (sd->flags & SD_WAKE_AFFINE) {
- cpumask_t domain_mask;
- int best_cpu;
+ if (alloc_cpumask_var(&domain_mask, GFP_ATOMIC)) {
+ for_each_domain(cpu, sd) {
+ if (sd->flags & SD_WAKE_AFFINE) {
+ int best_cpu;
+
+ cpumask_and(domain_mask,
+ sched_domain_span(sd),
+ lowest_mask);
- cpumask_and(&domain_mask, sched_domain_span(sd),
- lowest_mask);
+ best_cpu = pick_optimal_cpu(this_cpu,
+ domain_mask);
- best_cpu = pick_optimal_cpu(this_cpu,
- &domain_mask);
- if (best_cpu != -1)
- return best_cpu;
+ if (best_cpu != -1) {
+ free_cpumask_var(domain_mask);
+ return best_cpu;
+ }
+ }
}
+ free_cpumask_var(domain_mask);
}
/*
}
/* If this rq is still suitable use it. */
- if (lowest_rq->rt.highest_prio > task->prio)
+ if (lowest_rq->rt.highest_prio.curr > task->prio)
break;
/* try again */
return lowest_rq;
}
+ static inline int has_pushable_tasks(struct rq *rq)
+ {
+ return !plist_head_empty(&rq->rt.pushable_tasks);
+ }
+
+ 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->rt.nr_cpus_allowed <= 1);
+
+ BUG_ON(!p->se.on_rq);
+ 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
{
struct task_struct *next_task;
struct rq *lowest_rq;
- int ret = 0;
- int paranoid = RT_MAX_TRIES;
if (!rq->rt.overloaded)
return 0;
- next_task = pick_next_highest_task_rt(rq, -1);
+ next_task = pick_next_pushable_task(rq);
if (!next_task)
return 0;
struct task_struct *task;
/*
* find lock_lowest_rq releases rq->lock
- * so it is possible that next_task has changed.
- * If it has, then try again.
+ * 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_highest_task_rt(rq, -1);
- if (unlikely(task != next_task) && task && paranoid--) {
- put_task_struct(next_task);
- next_task = task;
- goto retry;
+ task = pick_next_pushable_task(rq);
+ if (task_cpu(next_task) == rq->cpu && task == next_task) {
+ /*
+ * If we get here, the task hasnt moved at all, but
+ * it has failed to push. We will not try again,
+ * since the other cpus will pull from us when they
+ * are ready.
+ */
+ dequeue_pushable_task(rq, next_task);
+ goto out;
}
- 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);
double_unlock_balance(rq, lowest_rq);
- ret = 1;
out:
put_task_struct(next_task);
- return ret;
+ return 1;
}
- /*
- * TODO: Currently we just use the second highest prio task on
- * the queue, and stop when it can't migrate (or there's
- * no more RT tasks). There may be a case where a lower
- * priority RT task has a different affinity than the
- * higher RT task. In this case the lower RT task could
- * possibly be able to migrate where as the higher priority
- * RT task could not. We currently ignore this issue.
- * Enhancements are welcome!
- */
static void push_rt_tasks(struct rq *rq)
{
/* push_rt_task will return true if it moved an RT */
static int pull_rt_task(struct rq *this_rq)
{
int this_cpu = this_rq->cpu, ret = 0, cpu;
- struct task_struct *p, *next;
+ struct task_struct *p;
struct rq *src_rq;
if (likely(!rt_overloaded(this_rq)))
return 0;
- next = pick_next_task_rt(this_rq);
-
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
- * steal our next task - hence we must cause
- * the caller to recalculate the next task
- * in that case:
+ * alter this_rq
*/
- if (double_lock_balance(this_rq, src_rq)) {
- struct task_struct *old_next = next;
-
- next = pick_next_task_rt(this_rq);
- if (next != old_next)
- ret = 1;
- }
+ double_lock_balance(this_rq, src_rq);
/*
* Are there still pullable RT tasks?
* Do we have an RT task that preempts
* the to-be-scheduled task?
*/
- if (p && (!next || (p->prio < next->prio))) {
+ if (p && (p->prio < this_rq->rt.highest_prio.curr)) {
WARN_ON(p == src_rq->curr);
WARN_ON(!p->se.on_rq);
* 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 or
- * this_rq next task is lower in prio than
- * the current task on that rq.
+ * current task on the run queue
*/
- if (p->prio < src_rq->curr->prio ||
- (next && next->prio < src_rq->curr->prio))
+ if (p->prio < src_rq->curr->prio)
goto skip;
ret = 1;
* case there's an even higher prio task
* in another runqueue. (low likelyhood
* but possible)
- *
- * Update next so that we won't pick a task
- * on another cpu with a priority lower (or equal)
- * than the one we just picked.
*/
- next = p;
-
}
skip:
double_unlock_balance(this_rq, src_rq);
static void pre_schedule_rt(struct rq *rq, struct task_struct *prev)
{
/* Try to pull RT tasks here if we lower this rq's prio */
- if (unlikely(rt_task(prev)) && rq->rt.highest_prio > prev->prio)
+ if (unlikely(rt_task(prev)) && rq->rt.highest_prio.curr > prev->prio)
pull_rt_task(rq);
}
+ /*
+ * assumes rq->lock is held
+ */
+ static int needs_post_schedule_rt(struct rq *rq)
+ {
+ return has_pushable_tasks(rq);
+ }
+
static void post_schedule_rt(struct rq *rq)
{
/*
- * If we have more than one rt_task queued, then
- * see if we can push the other rt_tasks off to other CPUS.
- * Note we may release the rq lock, and since
- * the lock was owned by prev, we need to release it
- * first via finish_lock_switch and then reaquire it here.
+ * This is only called if needs_post_schedule_rt() indicates that
+ * we need to push tasks away
*/
- if (unlikely(rq->rt.overloaded)) {
- spin_lock_irq(&rq->lock);
- push_rt_tasks(rq);
- spin_unlock_irq(&rq->lock);
- }
+ spin_lock_irq(&rq->lock);
+ push_rt_tasks(rq);
+ spin_unlock_irq(&rq->lock);
}
/*
{
if (!task_running(rq, p) &&
!test_tsk_need_resched(rq->curr) &&
- rq->rt.overloaded)
+ has_pushable_tasks(rq) &&
+ p->rt.nr_cpus_allowed > 1)
push_rt_tasks(rq);
}
if (p->se.on_rq && (weight != p->rt.nr_cpus_allowed)) {
struct rq *rq = task_rq(p);
+ if (!task_current(rq, p)) {
+ /*
+ * Make sure we dequeue this task from the pushable list
+ * before going further. It will either remain off of
+ * the list because we are no longer pushable, or it
+ * will be requeued.
+ */
+ if (p->rt.nr_cpus_allowed > 1)
+ dequeue_pushable_task(rq, p);
+
+ /*
+ * Requeue if our weight is changing and still > 1
+ */
+ if (weight > 1)
+ enqueue_pushable_task(rq, p);
+
+ }
+
if ((p->rt.nr_cpus_allowed <= 1) && (weight > 1)) {
rq->rt.rt_nr_migratory++;
} else if ((p->rt.nr_cpus_allowed > 1) && (weight <= 1)) {
rq->rt.rt_nr_migratory--;
}
- update_rt_migration(rq);
+ update_rt_migration(&rq->rt);
}
cpumask_copy(&p->cpus_allowed, new_mask);
__enable_runtime(rq);
- cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio);
+ cpupri_set(&rq->rd->cpupri, rq->cpu, rq->rt.highest_prio.curr);
}
/* Assumes rq->lock is held */
* can release the rq lock and p could migrate.
* Only reschedule if p is still on the same runqueue.
*/
- if (p->prio > rq->rt.highest_prio && rq->curr == p)
+ if (p->prio > rq->rt.highest_prio.curr && rq->curr == p)
resched_task(p);
#else
/* For UP simply resched on drop of prio */
struct task_struct *p = rq->curr;
p->se.exec_start = rq->clock;
+
+ /* The running task is never eligible for pushing */
+ dequeue_pushable_task(rq, p);
}
static const struct sched_class rt_sched_class = {
.rq_online = rq_online_rt,
.rq_offline = rq_offline_rt,
.pre_schedule = pre_schedule_rt,
+ .needs_post_schedule = needs_post_schedule_rt,
.post_schedule = post_schedule_rt,
.task_wake_up = task_wake_up_rt,
.switched_from = switched_from_rt,
git.openpandora.org / pandora-kernel.git / commitdiff