From: Juri Lelli <juri.le...@arm.com>
As we don't trigger freq changes from {en,de}queue_task_fair() during load
balancing, we need to do explicitly so on load balancing paths.
cc: Ingo Molnar <mi...@redhat.com>
cc: Peter Zijlstra <pet...@infradead.org>
Signed-off-by: Juri Lelli <juri.le...@arm.com>
---
kernel/sched/fair.c | 64 +++++++++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 62 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index c2d6de4..c513b19 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7741,6 +7741,20 @@ static int load_balance(int this_cpu, struct rq *this_rq,
* ld_moved - cumulative load moved across iterations
*/
cur_ld_moved = detach_tasks(&env);
+ /*
+ * We want to potentially update env.src_cpu's OPP.
+ *
+ * Add a margin (same ~20% used for the tipping point)
+ * to our request to provide some head room for the remaining
+ * tasks.
+ */
+ if (sched_energy_freq() && cur_ld_moved) {
+ unsigned long req_cap = get_cpu_usage(env.src_cpu);
+
+ req_cap = req_cap * capacity_margin
+ >> SCHED_CAPACITY_SHIFT;
+ cpufreq_sched_set_cap(env.src_cpu, req_cap);
+ }
/*
* We've detached some tasks from busiest_rq. Every
@@ -7755,6 +7769,21 @@ static int load_balance(int this_cpu, struct rq *this_rq,
if (cur_ld_moved) {
attach_tasks(&env);
ld_moved += cur_ld_moved;
+ /*
+ * We want to potentially update env.dst_cpu's OPP.
+ *
+ * Add a margin (same ~20% used for the tipping point)
+ * to our request to provide some head room if p's
+ * utilization further increases.
+ */
+ if (sched_energy_freq()) {
+ unsigned long req_cap =
+ get_cpu_usage(env.dst_cpu);
+
+ req_cap = req_cap * capacity_margin
+ >> SCHED_CAPACITY_SHIFT;
+ cpufreq_sched_set_cap(env.dst_cpu, req_cap);
+ }
}
local_irq_restore(flags);
@@ -8114,8 +8143,24 @@ static int active_load_balance_cpu_stop(void *data)
schedstat_inc(sd, alb_count);
p = detach_one_task(&env);
- if (p)
+ if (p) {
schedstat_inc(sd, alb_pushed);
+ /*
+ * We want to potentially update env.src_cpu's OPP.
+ *
+ * Add a margin (same ~20% used for the tipping point)
+ * to our request to provide some head room for the
+ * remaining task.
+ */
+ if (sched_energy_freq()) {
+ unsigned long req_cap =
+ get_cpu_usage(env.src_cpu);
+
+ req_cap = req_cap * capacity_margin
+ >> SCHED_CAPACITY_SHIFT;
+ cpufreq_sched_set_cap(env.src_cpu, req_cap);
+ }
+ }
else
schedstat_inc(sd, alb_failed);
}
@@ -8124,8 +8169,23 @@ static int active_load_balance_cpu_stop(void *data)
busiest_rq->active_balance = 0;
raw_spin_unlock(&busiest_rq->lock);
- if (p)
+ if (p) {
attach_one_task(target_rq, p);
+ /*
+ * We want to potentially update target_cpu's OPP.
+ *
+ * Add a margin (same ~20% used for the tipping point)
+ * to our request to provide some head room if p's utilization
+ * further increases.
+ */
+ if (sched_energy_freq()) {
+ unsigned long req_cap = get_cpu_usage(target_cpu);
+
+ req_cap = req_cap * capacity_margin
+ >> SCHED_CAPACITY_SHIFT;
+ cpufreq_sched_set_cap(target_cpu, req_cap);
+ }
+ }
local_irq_enable();
--
1.9.1
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