When combined with the next patch, which breaks out of rebalancing when an RT task is runnable, significant latency reductions are seen on systems with many CPUs. Signed-off-by: Scott Wood <swood@xxxxxxxxxx> --- kernel/sched/fair.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index ff369c38a5b5..aa8c87b6aff8 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10521,6 +10521,8 @@ static void nohz_newidle_balance(struct rq *this_rq) return; raw_spin_unlock(&this_rq->lock); + if (newidle_balance_in_callback) + local_irq_enable(); /* * This CPU is going to be idle and blocked load of idle CPUs * need to be updated. Run the ilb locally as it is a good @@ -10529,6 +10531,8 @@ static void nohz_newidle_balance(struct rq *this_rq) */ if (!_nohz_idle_balance(this_rq, NOHZ_STATS_KICK, CPU_NEWLY_IDLE)) kick_ilb(NOHZ_STATS_KICK); + if (newidle_balance_in_callback) + local_irq_disable(); raw_spin_lock(&this_rq->lock); } @@ -10599,6 +10603,8 @@ static int do_newidle_balance(struct rq *this_rq, struct rq_flags *rf) } raw_spin_unlock(&this_rq->lock); + if (newidle_balance_in_callback) + local_irq_enable(); update_blocked_averages(this_cpu); rcu_read_lock(); @@ -10636,6 +10642,8 @@ static int do_newidle_balance(struct rq *this_rq, struct rq_flags *rf) } rcu_read_unlock(); + if (newidle_balance_in_callback) + local_irq_disable(); raw_spin_lock(&this_rq->lock); if (curr_cost > this_rq->max_idle_balance_cost) -- 2.27.0
