[PATCH 12/13] hperf_hmp: rest of logic.
From: Arseniy Krasnov
Date: Fri Nov 06 2015 - 07:04:13 EST
Inserts call to main logic from 'load_balance', balance parameters
calculation during enqueue/dequeue task from runqueue and affinity mask
change callback for fair scheduling class.
Signed-off-by: Tarek Dakhran <t.dakhran@xxxxxxxxxxx>
Signed-off-by: Sergey Dyasly <s.dyasly@xxxxxxxxxxx>
Signed-off-by: Dmitriy Safonov <d.safonov@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Arseniy Krasnov <a.krasnov@xxxxxxxxxxx>
Signed-off-by: Ilya Maximets <i.maximets@xxxxxxxxxxx>
---
kernel/sched/fair.c | 204 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 202 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 79be023..06f6518 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -677,6 +677,16 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se)
}
#ifdef CONFIG_HPERF_HMP
+static void hmp_calculate_imbalance(void)
+{
+ if (atomic_long_read(&a7_total_weight) == 0) {
+ atomic_set(&hmp_imbalance, 0);
+ return;
+ }
+
+ atomic_set(&hmp_imbalance, 1);
+}
+
static bool
is_task_hmp(struct task_struct *task, const struct cpumask *task_cpus)
{
@@ -711,6 +721,13 @@ static inline void add_druntime_sum(struct rq *rq, long delta)
rq->druntime_sum += delta;
check_druntime_sum(rq, rq->druntime_sum);
}
+
+static inline void sub_druntime_sum(struct rq *rq, long delta)
+{
+ rq->druntime_sum -= delta;
+ check_druntime_sum(rq, rq->druntime_sum);
+}
+
/* Updates druntime for a task */
static inline void
update_hmp_stat(struct cfs_rq *cfs_rq, struct sched_entity *curr,
@@ -861,7 +878,9 @@ static void update_curr(struct cfs_rq *cfs_rq)
account_cfs_rq_runtime(cfs_rq, delta_exec);
+#ifdef CONFIG_HPERF_HMP
update_hmp_stat(cfs_rq, curr, delta_exec);
+#endif
}
static void update_curr_fair(struct rq *rq)
@@ -4200,6 +4219,66 @@ static inline void hrtick_update(struct rq *rq)
}
#endif
+#ifdef CONFIG_HPERF_HMP
+#ifdef CONFIG_HPERF_HMP_DEBUG
+static void check_nr_hmp_tasks(struct rq *rq)
+{
+ if (rq->nr_hmp_tasks > rq->cfs.h_nr_running) {
+ pr_emerg("HMP BUG: rq->nr_hmp_tasks = %u, "
+ "rq->cfs.h_nr_running = %u\n", rq->nr_hmp_tasks,
+ rq->cfs.h_nr_running);
+ BUG();
+ }
+}
+#else
+static void check_nr_hmp_tasks(struct rq *rq) { }
+#endif
+
+static void nr_hmp_tasks_inc(struct rq *rq)
+{
+ if (!rq->nr_hmp_tasks) {
+ if (cpu_is_fastest(rq->cpu))
+ atomic_inc(&a15_nr_hmp_busy);
+ else
+ atomic_inc(&a7_nr_hmp_busy);
+ }
+
+ rq->nr_hmp_tasks++;
+ check_nr_hmp_tasks(rq);
+}
+
+static void nr_hmp_tasks_dec(struct rq *rq)
+{
+ rq->nr_hmp_tasks--;
+
+ if (!rq->nr_hmp_tasks) {
+ if (cpu_is_fastest(rq->cpu))
+ atomic_dec(&a15_nr_hmp_busy);
+ else
+ atomic_dec(&a7_nr_hmp_busy);
+ }
+ check_nr_hmp_tasks(rq);
+}
+
+static void
+set_cpus_allowed_hmp(struct task_struct *p, const struct cpumask *new_mask)
+{
+ bool is_hmp_before, is_hmp_after;
+
+ cpumask_copy(&p->cpus_allowed, new_mask);
+ p->nr_cpus_allowed = cpumask_weight(new_mask);
+ is_hmp_before = is_task_hmp(p, NULL);
+ is_hmp_after = is_task_hmp(p, new_mask);
+
+ if (!p->on_cpu && p->se.on_rq && (is_hmp_before != is_hmp_after)) {
+ if (is_hmp_after)
+ nr_hmp_tasks_inc(rq_of(cfs_rq_of(&p->se)));
+ else
+ nr_hmp_tasks_dec(rq_of(cfs_rq_of(&p->se)));
+ }
+}
+#endif
+
/*
* The enqueue_task method is called before nr_running is
* increased. Here we update the fair scheduling stats and
@@ -4241,8 +4320,24 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_cfs_shares(cfs_rq);
}
- if (!se)
+ if (!se) {
add_nr_running(rq, 1);
+#ifdef CONFIG_HPERF_HMP
+ if (is_task_hmp(p, NULL))
+ nr_hmp_tasks_inc(rq);
+
+ if (cpu_is_fastest(rq->cpu)) {
+ atomic_long_add(p->se.load.weight, &a15_total_weight);
+ if (p->se.druntime < 0)
+ add_druntime_sum(rq, p->se.druntime);
+ } else {
+ atomic_long_add(p->se.load.weight, &a7_total_weight);
+ if (p->se.druntime > 0)
+ add_druntime_sum(rq, p->se.druntime);
+ }
+ hmp_calculate_imbalance();
+#endif
+ }
hrtick_update(rq);
}
@@ -4301,8 +4396,30 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags)
update_cfs_shares(cfs_rq);
}
- if (!se)
+ if (!se) {
sub_nr_running(rq, 1);
+#ifdef CONFIG_HPERF_HMP
+ if (is_task_hmp(p, NULL))
+ nr_hmp_tasks_dec(rq);
+
+ /*
+ * Set this field to 0 because if task selected for migration
+ * fall asleep it will never be selected again for migration.
+ */
+ p->se.migrate_candidate = 0;
+
+ if (cpu_is_fastest(rq->cpu)) {
+ atomic_long_sub(p->se.load.weight, &a15_total_weight);
+ if (p->se.druntime < 0)
+ sub_druntime_sum(rq, p->se.druntime);
+ } else {
+ atomic_long_sub(p->se.load.weight, &a7_total_weight);
+ if (p->se.druntime > 0)
+ sub_druntime_sum(rq, p->se.druntime);
+ }
+ hmp_calculate_imbalance();
+#endif
+ }
hrtick_update(rq);
}
@@ -5848,6 +5965,11 @@ int can_migrate_task(struct task_struct *p, struct lb_env *env)
}
schedstat_inc(p, se.statistics.nr_failed_migrations_hot);
+
+#ifdef CONFIG_HPERF_HMP
+ if (env->src_rq->migrate_task) /*idle pull*/
+ return 1;
+#endif
return 0;
}
@@ -5879,6 +6001,10 @@ static struct task_struct *detach_one_task(struct lb_env *env)
if (!can_migrate_task(p, env))
continue;
+#ifdef CONFIG_HPERF_HMP
+ if (p->se.migrate_candidate)
+ continue;
+#endif
detach_task(p, env);
/*
@@ -5946,6 +6072,10 @@ static int detach_tasks(struct lb_env *env)
if ((load / 2) > env->imbalance)
goto next;
+#ifdef CONFIG_HPERF_HMP
+ if (p->se.migrate_candidate)
+ goto next;
+#endif
detach_task(p, env);
list_add(&p->se.group_node, &env->tasks);
@@ -7909,6 +8039,44 @@ unlock:
return ld_moved;
}
+
+/**
+ * hmp_do_rebalance(): Checks imbalance in HMP domain and performs balancing.
+ *
+ * @sd: Current sched domain.
+ * @this_cpu: without NO_HZ same as smp_processor_id().
+ *
+ * Returns moved weight.
+ */
+static unsigned int hmp_do_rebalance(struct sched_domain *sd, int this_cpu)
+{
+ unsigned int ld_moved = 0;
+ switch (is_hmp_imbalance(sd)) {
+ case SWAP_TASKS:
+ ld_moved = swap_tasks(sd, this_cpu);
+ break;
+ case A15_TO_A7:
+ ld_moved = move_a15_to_a7(sd, this_cpu);
+ break;
+ case A7_TO_A15:
+ ld_moved = move_a7_to_a15(sd, this_cpu);
+ break;
+ case SKIP_REBALANCE:
+ default:
+ break;
+ }
+ return ld_moved;
+}
+
+/* HMP balancing entry point */
+static unsigned int hmp_load_balance(struct sched_domain *sd,
+ enum cpu_idle_type idle, int this_cpu)
+{
+ if (idle == CPU_NEWLY_IDLE || idle == CPU_IDLE)
+ return hmp_idle_pull(sd, this_cpu);
+ else
+ return hmp_do_rebalance(sd, this_cpu);
+}
#endif /* CONFIG_HPERF_HMP */
/*
@@ -7938,6 +8106,11 @@ static int load_balance(int this_cpu, struct rq *this_rq,
.tasks = LIST_HEAD_INIT(env.tasks),
};
+#ifdef CONFIG_HPERF_HMP
+ /* It is HMP domain, so branch to HPERF_HMP logic */
+ if (sd->flags & SD_HMP_BALANCE)
+ return hmp_load_balance(sd, idle, this_cpu);
+#endif
/*
* For NEWLY_IDLE load_balancing, we don't need to consider
* other cpus in our group
@@ -8322,6 +8495,14 @@ static int active_load_balance_cpu_stop(void *data)
struct sched_domain *sd;
struct task_struct *p = NULL;
+#ifdef CONFIG_HPERF_HMP_DEBUG
+ if (!cpumask_test_cpu(target_cpu, cpu_fastest_mask) &&
+ !cpumask_test_cpu(target_cpu, cpu_slowest_mask)) {
+ pr_emerg("hperf_hmp: %s: for CPU#%i target_cpu is invalid: %i!\n",
+ __func__, busiest_cpu, target_cpu);
+ BUG();
+ }
+#endif
raw_spin_lock_irq(&busiest_rq->lock);
/* make sure the requested cpu hasn't gone down in the meantime */
@@ -8349,6 +8530,9 @@ static int active_load_balance_cpu_stop(void *data)
}
if (likely(sd)) {
+#ifdef CONFIG_HPERF_HMP
+ struct task_struct *migrate_task;
+#endif
struct lb_env env = {
.sd = sd,
.dst_cpu = target_cpu,
@@ -8360,7 +8544,19 @@ static int active_load_balance_cpu_stop(void *data)
schedstat_inc(sd, alb_count);
+#ifdef CONFIG_HPERF_HMP
+ if (env.src_rq->migrate_task) {
+ migrate_task = env.src_rq->migrate_task;
+ p = detach_specified_task(migrate_task, &env);
+ if (p)
+ migrate_task->se.last_migration = jiffies;
+ env.src_rq->migrate_task = NULL;
+ } else {
+ p = detach_one_task(&env);
+ }
+#else
p = detach_one_task(&env);
+#endif
if (p)
schedstat_inc(sd, alb_pushed);
else
@@ -9267,8 +9463,12 @@ const struct sched_class fair_sched_class = {
.task_waking = task_waking_fair,
.task_dead = task_dead_fair,
+#ifdef CONFIG_HPERF_HMP
+ .set_cpus_allowed = set_cpus_allowed_hmp,
+#else
.set_cpus_allowed = set_cpus_allowed_common,
#endif
+#endif
.set_curr_task = set_curr_task_fair,
.task_tick = task_tick_fair,
--
1.9.1
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