sched/deadline: Make find_later_rq() choose a closer CPU in topology (b18c3ca1) · Commits · 戴 / test

kernel/sched/deadline.c

+14 −13

Original line number	Original line	Diff line number	Diff line
	@@ -1798,7 +1798,7 @@ static int find_later_rq(struct task_struct *task)
	struct sched_domain *sd;		struct sched_domain *sd;
	struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);		struct cpumask *later_mask = this_cpu_cpumask_var_ptr(local_cpu_mask_dl);
	int this_cpu = smp_processor_id();		int this_cpu = smp_processor_id();
	int best_cpu, cpu = task_cpu(task);		int cpu = task_cpu(task);

	/* Make sure the mask is initialized first */		/* Make sure the mask is initialized first */
	if (unlikely(!later_mask))		if (unlikely(!later_mask))
	@@ -1811,17 +1811,14 @@ static int find_later_rq(struct task_struct *task)
	* We have to consider system topology and task affinity		* We have to consider system topology and task affinity
	* first, then we can look for a suitable cpu.		* first, then we can look for a suitable cpu.
	*/		*/
	best_cpu = cpudl_find(&task_rq(task)->rd->cpudl,		if (cpudl_find(&task_rq(task)->rd->cpudl, task, later_mask) == -1)
	task, later_mask);
	if (best_cpu == -1)
	return -1;		return -1;

	/*		/*
	* If we are here, some target has been found,		* If we are here, some targets have been found, including
	* the most suitable of which is cached in best_cpu.		* the most suitable which is, among the runqueues where the
	* This is, among the runqueues where the current tasks		* current tasks have later deadlines than the task's one, the
	* have later deadlines than the task's one, the rq		* rq with the latest possible one.
	* with the latest possible one.
	*		*
	* Now we check how well this matches with task's		* Now we check how well this matches with task's
	* affinity and system topology.		* affinity and system topology.
	@@ -1841,6 +1838,7 @@ static int find_later_rq(struct task_struct *task)
	rcu_read_lock();		rcu_read_lock();
	for_each_domain(cpu, sd) {		for_each_domain(cpu, sd) {
	if (sd->flags & SD_WAKE_AFFINE) {		if (sd->flags & SD_WAKE_AFFINE) {
			int best_cpu;

	/*		/*
	* If possible, preempting this_cpu is		* If possible, preempting this_cpu is
	@@ -1852,12 +1850,15 @@ static int find_later_rq(struct task_struct *task)
	return this_cpu;		return this_cpu;
	}		}

			best_cpu = cpumask_first_and(later_mask,
			sched_domain_span(sd));
	/*		/*
	* Last chance: if best_cpu is valid and is		* Last chance: if a cpu being in both later_mask
	* in the mask, that becomes our choice.		* and current sd span is valid, that becomes our
			* choice. Of course, the latest possible cpu is
			* already under consideration through later_mask.
	*/		*/
	if (best_cpu < nr_cpu_ids &&		if (best_cpu < nr_cpu_ids) {
	cpumask_test_cpu(best_cpu, sched_domain_span(sd))) {
	rcu_read_unlock();		rcu_read_unlock();
	return best_cpu;		return best_cpu;
	}		}

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