Update the cpu_load of the kickee in run_rebalance_domains before
calling rebalance_domains if the kickee is in nohz_idle. This avoids
using stale cpu_load for the subsequent load_balance.
cpu_load in the nohz path is updated on tick_nohz_idle_exit or if a
kickee performances balancing on the behalf of tickless cpus in
nohz_idle_balance. However, the kickee's cpu_load is never updated if it
doesn't exit nohz_idle. This causes stale cpu_load to be used which
causes incorrect load balancing decisions.
Tested on k3.10.
Signed-off-by: Sai Gurrappadi <sgurrapp...@nvidia.com>
---
kernel/sched/fair.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 860a152..1d4eb4a 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -7140,6 +7140,13 @@ static void run_rebalance_domains(struct
softirq_action *h)
enum cpu_idle_type idle = this_rq->idle_balance ?
CPU_IDLE : CPU_NOT_IDLE;
+ if (test_bit(NOHZ_BALANCE_KICK, nohz_flags(this_rq->cpu))) {
+ raw_spin_lock_irq(&this_rq->lock);
+ update_rq_clock(this_rq);
+ update_idle_cpu_load(this_rq);
+ raw_spin_unlock_irq(&this_rq->lock);
+ }
+
rebalance_domains(this_rq, idle);
/*
--
1.8.1.5
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