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Date: Fri, 06 Nov 2015 15:02:43 +0300
From: Arseniy Krasnov <a.krasnov@...sung.com>
To: linux@....linux.org.uk, mingo@...hat.com, peterz@...radead.org
Cc: a.krasnov@...sung.com, v.tyrtov@...sung.com,
s.rogachev@...sung.com, linux-kernel@...r.kernel.org,
Tarek Dakhran <t.dakhran@...sung.com>,
Sergey Dyasly <s.dyasly@...sung.com>,
Dmitriy Safonov <d.safonov@...tner.samsung.com>,
Ilya Maximets <i.maximets@...sung.com>
Subject: [PATCH 09/13] hperf_hmp: one way balancing function.
Almost identical functions which push/pull task from/to current CPU
to/from another cluster. Called when balancing between clusters is broken and we
need to fix it.
Signed-off-by: Tarek Dakhran <t.dakhran@...sung.com>
Signed-off-by: Sergey Dyasly <s.dyasly@...sung.com>
Signed-off-by: Dmitriy Safonov <d.safonov@...tner.samsung.com>
Signed-off-by: Arseniy Krasnov <a.krasnov@...sung.com>
Signed-off-by: Ilya Maximets <i.maximets@...sung.com>
---
kernel/sched/fair.c | 254 ++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 254 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 028d329..4fda1ec 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7519,6 +7519,260 @@ unlock:
return ld_moved;
}
+
+/* Get idlest cpu from opposite domain of this_cpu */
+static int get_idlest_cpu(struct sched_domain *sd, int this_cpu)
+{
+ struct sched_group *opposite_sg;
+ struct cpumask *opposite_mask;
+ unsigned long load = ULONG_MAX;
+ int idlest_cpu = -1;
+ int cpu;
+
+ opposite_sg = get_opposite_group(sd, cpu_is_fastest(this_cpu));
+ opposite_mask = sched_group_cpus(opposite_sg);
+
+ for_each_cpu_and(cpu, opposite_mask, cpu_online_mask) {
+ if (cpu_rq(cpu)->load.weight < load) {
+ load = cpu_rq(cpu)->load.weight;
+ idlest_cpu = cpu;
+ }
+ }
+ return idlest_cpu;
+}
+
+/**
+ * move_a15_to_a7(): Moves one task from A15 to A7.
+ * @sd: Current sched domain.
+ * @this_cpu: without NO_HZ same as smp_processor_id().
+ *
+ * Returns moved weight.
+ *
+ * Chooses task to migrate by druntime.
+ */
+static unsigned int move_a15_to_a7(struct sched_domain *sd, int this_cpu)
+{
+ struct task_struct *task_to_move;
+ struct rq *local_rq = NULL;
+ struct rq *foreign_rq = NULL;
+ int local_stopper_flag = 0;
+ int foreign_stopper_flag = 0;
+ unsigned long local_flags;
+ unsigned int ld_moved = 0;
+
+ local_rq = cpu_rq(this_cpu);
+ local_irq_save(local_flags);
+
+ if (!cpu_is_fastest(this_cpu)) {
+ /* this A7 pulls task from A15 */
+ foreign_rq = get_unfair_rq(sd, this_cpu);
+
+ if (!foreign_rq) {
+ local_irq_restore(local_flags);
+ return 0;
+ }
+
+ double_lock_balance(foreign_rq, local_rq);
+
+ if (foreign_rq->active_balance)
+ goto unlock;
+
+ if (local_rq->active_balance)
+ goto unlock;
+
+ if (foreign_rq->cfs.h_nr_running <= 1)
+ goto unlock;
+
+ task_to_move = get_migration_candidate(sd, foreign_rq, 0,
+ this_cpu);
+
+ if (!task_to_move)
+ goto unlock;
+
+ ld_moved = try_to_move_task(task_to_move, this_cpu,
+ &foreign_stopper_flag);
+
+ if (!ld_moved) {
+ task_to_move->se.migrate_candidate = 0;
+ goto unlock;
+ }
+
+ if (foreign_stopper_flag) {
+ foreign_rq->active_balance = 1;
+ foreign_rq->push_cpu = this_cpu;
+ foreign_rq->migrate_task = task_to_move;
+ }
+ } else {
+ /* this A15 push task to A7 */
+ int dst_cpu = get_idlest_cpu(sd, this_cpu);
+
+ if (dst_cpu == -1) {
+ local_irq_restore(local_flags);
+ return 0;
+ }
+
+ foreign_rq = cpu_rq(dst_cpu);
+ raw_spin_lock(&foreign_rq->lock);
+ double_lock_balance(foreign_rq, local_rq);
+
+ if (local_rq->cfs.h_nr_running <= 1)
+ goto unlock;
+
+ if (foreign_rq->active_balance)
+ goto unlock;
+
+ if (local_rq->active_balance)
+ goto unlock;
+
+ task_to_move = get_migration_candidate(sd, local_rq, 0,
+ foreign_rq->cpu);
+
+ if (!task_to_move)
+ goto unlock;
+
+ ld_moved = try_to_move_task(task_to_move, dst_cpu,
+ &local_stopper_flag);
+
+ if (!ld_moved) {
+ task_to_move->se.migrate_candidate = 0;
+ goto unlock;
+ }
+
+ if (local_stopper_flag) {
+ local_rq->active_balance = 1;
+ local_rq->push_cpu = dst_cpu;
+ local_rq->migrate_task = task_to_move;
+ }
+ }
+unlock:
+ double_rq_unlock(local_rq, foreign_rq);
+ local_irq_restore(local_flags);
+
+ if (foreign_stopper_flag)
+ stop_one_cpu_nowait(foreign_rq->cpu,
+ active_load_balance_cpu_stop, foreign_rq,
+ &foreign_rq->active_balance_work);
+
+ if (local_stopper_flag)
+ stop_one_cpu_nowait(local_rq->cpu,
+ active_load_balance_cpu_stop, local_rq,
+ &local_rq->active_balance_work);
+
+ return ld_moved;
+}
+
+/**
+ * move_a7_to_a15(): Moves one task from A7 to A15.
+ * @sd: Current sched domain.
+ * @this_cpu: without NO_HZ same as smp_processor_id().
+ *
+ * Returns moved weight.
+ *
+ * Chooses task to migrate by druntime.
+ */
+static unsigned int move_a7_to_a15(struct sched_domain *sd, int this_cpu)
+{
+ struct task_struct *task_to_move;
+ struct rq *local_rq = NULL;
+ struct rq *foreign_rq = NULL;
+ int local_stopper_flag = 0;
+ int foreign_stopper_flag = 0;
+ unsigned long local_flags;
+ unsigned int ld_moved = 0;
+
+ local_rq = cpu_rq(this_cpu);
+ local_irq_save(local_flags);
+
+ if (cpu_is_fastest(this_cpu)) {
+ /* this A15 pulls task from A7 */
+ foreign_rq = get_unfair_rq(sd, this_cpu);
+
+ if (!foreign_rq) {
+ local_irq_restore(local_flags);
+ return 0;
+ }
+ double_lock_balance(foreign_rq, local_rq);
+
+ if (local_rq->active_balance)
+ goto unlock;
+
+ if (foreign_rq->active_balance)
+ goto unlock;
+
+ task_to_move = get_migration_candidate(sd, foreign_rq, 0,
+ this_cpu);
+
+ if (!task_to_move)
+ goto unlock;
+
+ ld_moved = try_to_move_task(task_to_move, this_cpu,
+ &foreign_stopper_flag);
+
+ if (!ld_moved) {
+ task_to_move->se.migrate_candidate = 0;
+ goto unlock;
+ }
+
+ if (foreign_stopper_flag) {
+ foreign_rq->active_balance = 1;
+ foreign_rq->push_cpu = this_cpu;
+ foreign_rq->migrate_task = task_to_move;
+ }
+ } else {
+ /* this A7 push task to A15*/
+ int dst_cpu = get_idlest_cpu(sd, this_cpu);
+
+ if (dst_cpu == -1) {
+ local_irq_restore(local_flags);
+ return 0;
+ }
+
+ foreign_rq = cpu_rq(dst_cpu);
+ raw_spin_lock(&foreign_rq->lock);
+ double_lock_balance(foreign_rq, local_rq);
+
+ if (foreign_rq->active_balance)
+ goto unlock;
+
+ if (local_rq->active_balance)
+ goto unlock;
+
+ task_to_move = get_migration_candidate(sd, local_rq, 0,
+ foreign_rq->cpu);
+
+ if (!task_to_move)
+ goto unlock;
+
+ ld_moved = try_to_move_task(task_to_move, dst_cpu,
+ &local_stopper_flag);
+
+ if (!ld_moved) {
+ task_to_move->se.migrate_candidate = 0;
+ goto unlock;
+ }
+
+ if (local_stopper_flag) {
+ local_rq->active_balance = 1;
+ local_rq->push_cpu = dst_cpu;
+ local_rq->migrate_task = task_to_move;
+ }
+ }
+unlock:
+ double_rq_unlock(local_rq, foreign_rq);
+ local_irq_restore(local_flags);
+
+ if (foreign_stopper_flag)
+ stop_one_cpu_nowait(foreign_rq->cpu,
+ active_load_balance_cpu_stop, foreign_rq,
+ &foreign_rq->active_balance_work);
+
+ if (local_stopper_flag)
+ stop_one_cpu_nowait(local_rq->cpu,
+ active_load_balance_cpu_stop, local_rq,
+ &local_rq->active_balance_work);
+
+ return ld_moved;
+}
#endif /* CONFIG_HPERF_HMP */
/*
--
1.9.1
--
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