sched, nohz: Exclude isolated cores from load balancing (d987fc7f) · Commits · 戴 / test

kernel/sched/fair.c

+18 −7

Original line number	Diff line number	Diff line
		@@ -6788,6 +6788,11 @@ out_unlock:
		return 0;
		}

		static inline int on_null_domain(struct rq *rq)
		{
		return unlikely(!rcu_dereference_sched(rq->sd));
		}

		#ifdef CONFIG_NO_HZ_COMMON
		/*
		* idle load balancing details
		@@ -6842,8 +6847,13 @@ static void nohz_balancer_kick(void)
		static inline void nohz_balance_exit_idle(int cpu)
		{
		if (unlikely(test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))) {
		/*
		* Completely isolated CPUs don't ever set, so we must test.
		*/
		if (likely(cpumask_test_cpu(cpu, nohz.idle_cpus_mask))) {
		cpumask_clear_cpu(cpu, nohz.idle_cpus_mask);
		atomic_dec(&nohz.nr_cpus);
		}
		clear_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
		}
		}
		@@ -6897,6 +6907,12 @@ void nohz_balance_enter_idle(int cpu)
		if (test_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu)))
		return;

		/*
		* If we're a completely isolated CPU, we don't play.
		*/
		if (on_null_domain(cpu_rq(cpu)))
		return;

		cpumask_set_cpu(cpu, nohz.idle_cpus_mask);
		atomic_inc(&nohz.nr_cpus);
		set_bit(NOHZ_TICK_STOPPED, nohz_flags(cpu));
		@@ -7159,11 +7175,6 @@ static void run_rebalance_domains(struct softirq_action *h)
		nohz_idle_balance(this_rq, idle);
		}

		static inline int on_null_domain(struct rq *rq)
		{
		return !rcu_dereference_sched(rq->sd);
		}

		/*
		* Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing.
		*/