*/
unsigned int __read_mostly sysctl_sched_compat_yield;
-/*
- * SCHED_BATCH wake-up granularity.
- * (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
- *
- * This option delays the preemption effects of decoupled workloads
- * and reduces their over-scheduling. Synchronous workloads will still
- * have immediate wakeup/sleep latencies.
- */
-unsigned int sysctl_sched_batch_wakeup_granularity = 10000000UL;
-
/*
* SCHED_OTHER wake-up granularity.
* (default: 10 msec * (1 + ilog(ncpus)), units: nanoseconds)
return vslice;
}
-static u64 sched_vslice(struct cfs_rq *cfs_rq)
-{
- return __sched_vslice(cfs_rq->load.weight, cfs_rq->nr_running);
-}
-
static u64 sched_vslice_add(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
return __sched_vslice(cfs_rq->load.weight + se->load.weight,
} else
vruntime = cfs_rq->min_vruntime;
- if (sched_feat(TREE_AVG)) {
- struct sched_entity *last = __pick_last_entity(cfs_rq);
- if (last) {
- vruntime += last->vruntime;
- vruntime >>= 1;
- }
- } else if (sched_feat(APPROX_AVG) && cfs_rq->nr_running)
- vruntime += sched_vslice(cfs_rq)/2;
-
/*
* The 'current' period is already promised to the current tasks,
* however the extra weight of the new task will slow them down a
account_entity_enqueue(cfs_rq, se);
}
+static void update_avg(u64 *avg, u64 sample)
+{
+ s64 diff = sample - *avg;
+ *avg += diff >> 3;
+}
+
+static void update_avg_stats(struct cfs_rq *cfs_rq, struct sched_entity *se)
+{
+ if (!se->last_wakeup)
+ return;
+
+ update_avg(&se->avg_overlap, se->sum_exec_runtime - se->last_wakeup);
+ se->last_wakeup = 0;
+}
+
static void
dequeue_entity(struct cfs_rq *cfs_rq, struct sched_entity *se, int sleep)
{
update_stats_dequeue(cfs_rq, se);
if (sleep) {
+ update_avg_stats(cfs_rq, se);
#ifdef CONFIG_SCHEDSTATS
if (entity_is_task(se)) {
struct task_struct *tsk = task_of(se);
se->prev_sum_exec_runtime = se->sum_exec_runtime;
}
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se);
+
static struct sched_entity *
pick_next(struct cfs_rq *cfs_rq, struct sched_entity *se)
{
- s64 diff, gran;
-
if (!cfs_rq->next)
return se;
- diff = cfs_rq->next->vruntime - se->vruntime;
- if (diff < 0)
- return se;
-
- gran = calc_delta_fair(sysctl_sched_wakeup_granularity, &cfs_rq->load);
- if (diff > gran)
+ if (wakeup_preempt_entity(cfs_rq->next, se) != 0)
return se;
return cfs_rq->next;
#endif
#ifdef CONFIG_SMP
-static int select_task_rq_fair(struct task_struct *p, int sync)
+
+static const struct sched_class fair_sched_class;
+
+static int
+wake_affine(struct rq *rq, struct sched_domain *this_sd, struct rq *this_rq,
+ struct task_struct *p, int prev_cpu, int this_cpu, int sync,
+ int idx, unsigned long load, unsigned long this_load,
+ unsigned int imbalance)
{
- int cpu, this_cpu;
- struct rq *rq;
- struct sched_domain *sd, *this_sd = NULL;
- int new_cpu;
+ struct task_struct *curr = this_rq->curr;
+ unsigned long tl = this_load;
+ unsigned long tl_per_task;
+
+ if (!(this_sd->flags & SD_WAKE_AFFINE))
+ return 0;
+
+ /*
+ * If the currently running task will sleep within
+ * a reasonable amount of time then attract this newly
+ * woken task:
+ */
+ if (sync && curr->sched_class == &fair_sched_class) {
+ if (curr->se.avg_overlap < sysctl_sched_migration_cost &&
+ p->se.avg_overlap < sysctl_sched_migration_cost)
+ return 1;
+ }
+
+ schedstat_inc(p, se.nr_wakeups_affine_attempts);
+ tl_per_task = cpu_avg_load_per_task(this_cpu);
- cpu = task_cpu(p);
- rq = task_rq(p);
- this_cpu = smp_processor_id();
- new_cpu = cpu;
+ /*
+ * If sync wakeup then subtract the (maximum possible)
+ * effect of the currently running task from the load
+ * of the current CPU:
+ */
+ if (sync)
+ tl -= current->se.load.weight;
+
+ if ((tl <= load && tl + target_load(prev_cpu, idx) <= tl_per_task) ||
+ 100*(tl + p->se.load.weight) <= imbalance*load) {
+ /*
+ * This domain has SD_WAKE_AFFINE and
+ * p is cache cold in this domain, and
+ * there is no bad imbalance.
+ */
+ schedstat_inc(this_sd, ttwu_move_affine);
+ schedstat_inc(p, se.nr_wakeups_affine);
- if (cpu == this_cpu)
- goto out_set_cpu;
+ return 1;
+ }
+ return 0;
+}
+static int select_task_rq_fair(struct task_struct *p, int sync)
+{
+ struct sched_domain *sd, *this_sd = NULL;
+ int prev_cpu, this_cpu, new_cpu;
+ unsigned long load, this_load;
+ struct rq *rq, *this_rq;
+ unsigned int imbalance;
+ int idx;
+
+ prev_cpu = task_cpu(p);
+ rq = task_rq(p);
+ this_cpu = smp_processor_id();
+ this_rq = cpu_rq(this_cpu);
+ new_cpu = prev_cpu;
+
+ /*
+ * 'this_sd' is the first domain that both
+ * this_cpu and prev_cpu are present in:
+ */
for_each_domain(this_cpu, sd) {
- if (cpu_isset(cpu, sd->span)) {
+ if (cpu_isset(prev_cpu, sd->span)) {
this_sd = sd;
break;
}
}
if (unlikely(!cpu_isset(this_cpu, p->cpus_allowed)))
- goto out_set_cpu;
+ goto out;
/*
* Check for affine wakeup and passive balancing possibilities.
*/
- if (this_sd) {
- int idx = this_sd->wake_idx;
- unsigned int imbalance;
- unsigned long load, this_load;
-
- imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
-
- load = source_load(cpu, idx);
- this_load = target_load(this_cpu, idx);
-
- new_cpu = this_cpu; /* Wake to this CPU if we can */
-
- if (this_sd->flags & SD_WAKE_AFFINE) {
- unsigned long tl = this_load;
- unsigned long tl_per_task;
-
- /*
- * Attract cache-cold tasks on sync wakeups:
- */
- if (sync && !task_hot(p, rq->clock, this_sd))
- goto out_set_cpu;
-
- schedstat_inc(p, se.nr_wakeups_affine_attempts);
- tl_per_task = cpu_avg_load_per_task(this_cpu);
-
- /*
- * If sync wakeup then subtract the (maximum possible)
- * effect of the currently running task from the load
- * of the current CPU:
- */
- if (sync)
- tl -= current->se.load.weight;
-
- if ((tl <= load &&
- tl + target_load(cpu, idx) <= tl_per_task) ||
- 100*(tl + p->se.load.weight) <= imbalance*load) {
- /*
- * This domain has SD_WAKE_AFFINE and
- * p is cache cold in this domain, and
- * there is no bad imbalance.
- */
- schedstat_inc(this_sd, ttwu_move_affine);
- schedstat_inc(p, se.nr_wakeups_affine);
- goto out_set_cpu;
- }
- }
+ if (!this_sd)
+ goto out;
- /*
- * Start passive balancing when half the imbalance_pct
- * limit is reached.
- */
- if (this_sd->flags & SD_WAKE_BALANCE) {
- if (imbalance*this_load <= 100*load) {
- schedstat_inc(this_sd, ttwu_move_balance);
- schedstat_inc(p, se.nr_wakeups_passive);
- goto out_set_cpu;
- }
+ idx = this_sd->wake_idx;
+
+ imbalance = 100 + (this_sd->imbalance_pct - 100) / 2;
+
+ load = source_load(prev_cpu, idx);
+ this_load = target_load(this_cpu, idx);
+
+ if (wake_affine(rq, this_sd, this_rq, p, prev_cpu, this_cpu, sync, idx,
+ load, this_load, imbalance))
+ return this_cpu;
+
+ if (prev_cpu == this_cpu)
+ goto out;
+
+ /*
+ * Start passive balancing when half the imbalance_pct
+ * limit is reached.
+ */
+ if (this_sd->flags & SD_WAKE_BALANCE) {
+ if (imbalance*this_load <= 100*load) {
+ schedstat_inc(this_sd, ttwu_move_balance);
+ schedstat_inc(p, se.nr_wakeups_passive);
+ return this_cpu;
}
}
- new_cpu = cpu; /* Could not wake to this_cpu. Wake to cpu instead */
-out_set_cpu:
+out:
return wake_idle(new_cpu, p);
}
#endif /* CONFIG_SMP */
+static unsigned long wakeup_gran(struct sched_entity *se)
+{
+ unsigned long gran = sysctl_sched_wakeup_granularity;
+
+ /*
+ * More easily preempt - nice tasks, while not making
+ * it harder for + nice tasks.
+ */
+ if (unlikely(se->load.weight > NICE_0_LOAD))
+ gran = calc_delta_fair(gran, &se->load);
+
+ return gran;
+}
+
+/*
+ * Should 'se' preempt 'curr'.
+ *
+ * |s1
+ * |s2
+ * |s3
+ * g
+ * |<--->|c
+ *
+ * w(c, s1) = -1
+ * w(c, s2) = 0
+ * w(c, s3) = 1
+ *
+ */
+static int
+wakeup_preempt_entity(struct sched_entity *curr, struct sched_entity *se)
+{
+ s64 gran, vdiff = curr->vruntime - se->vruntime;
+
+ if (vdiff < 0)
+ return -1;
+
+ gran = wakeup_gran(curr);
+ if (vdiff > gran)
+ return 1;
+
+ return 0;
+}
/*
* Preempt the current task with a newly woken task if needed:
struct task_struct *curr = rq->curr;
struct cfs_rq *cfs_rq = task_cfs_rq(curr);
struct sched_entity *se = &curr->se, *pse = &p->se;
- unsigned long gran;
if (unlikely(rt_prio(p->prio))) {
update_rq_clock(rq);
return;
}
+ se->last_wakeup = se->sum_exec_runtime;
+ if (unlikely(se == pse))
+ return;
+
cfs_rq_of(pse)->next = pse;
/*
pse = parent_entity(pse);
}
- gran = sysctl_sched_wakeup_granularity;
- /*
- * More easily preempt - nice tasks, while not making
- * it harder for + nice tasks.
- */
- if (unlikely(se->load.weight > NICE_0_LOAD))
- gran = calc_delta_fair(gran, &se->load);
-
- if (pse->vruntime + gran < se->vruntime)
+ if (wakeup_preempt_entity(se, pse) == 1)
resched_task(curr);
}
projects / deliverable / linux.git / blobdiff