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Commit 0c0e776a authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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sched/topology: Rewrite get_group() 



We want to attain:

  sg_cpus() & sg_mask() == sg_mask()

for this to be so we must initialize sg_mask() to sg_cpus() for the
!overlap case (its currently cpumask_setall()).

Since the code makes my head hurt bad, rewrite it into a simpler form,
inspired by the now fixed overlap code.

Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 35a566e6

kernel/sched/topology.c

+22 −24
Original line number Diff line number Diff line
@@ -833,23 +833,34 @@ build_overlap_sched_groups(struct sched_domain *sd, int cpu) 
 * [*] in other words, the first group of each domain is its child domain.

 */



static int get_group(int cpu, struct sd_data *sdd, struct sched_group **sg)

static struct sched_group *get_group(int cpu, struct sd_data *sdd)

{

	struct sched_domain *sd = *per_cpu_ptr(sdd->sd, cpu);

	struct sched_domain *child = sd->child;

	struct sched_group *sg;



	if (child)

		cpu = cpumask_first(sched_domain_span(child));



	if (sg) {

		*sg = *per_cpu_ptr(sdd->sg, cpu);

		(*sg)->sgc = *per_cpu_ptr(sdd->sgc, cpu);

	sg = *per_cpu_ptr(sdd->sg, cpu);

	sg->sgc = *per_cpu_ptr(sdd->sgc, cpu);



	/* For claim_allocations: */

		atomic_set(&(*sg)->sgc->ref, 1);

	atomic_inc(&sg->ref);

	atomic_inc(&sg->sgc->ref);



	if (child) {

		cpumask_copy(sched_group_cpus(sg), sched_domain_span(child));

		cpumask_copy(sched_group_mask(sg), sched_group_cpus(sg));

	} else {

		cpumask_set_cpu(cpu, sched_group_cpus(sg));

		cpumask_set_cpu(cpu, sched_group_mask(sg));

	}



	return cpu;

	sg->sgc->capacity = SCHED_CAPACITY_SCALE * cpumask_weight(sched_group_cpus(sg));

	sg->sgc->min_capacity = SCHED_CAPACITY_SCALE;



	return sg;

}



/*
@@ -868,34 +879,20 @@ build_sched_groups(struct sched_domain *sd, int cpu) 
	struct cpumask *covered;

	int i;



	get_group(cpu, sdd, &sd->groups);

	atomic_inc(&sd->groups->ref);



	if (cpu != cpumask_first(span))

		return 0;



	lockdep_assert_held(&sched_domains_mutex);

	covered = sched_domains_tmpmask;



	cpumask_clear(covered);



	for_each_cpu(i, span) {

	for_each_cpu_wrap(i, span, cpu) {

		struct sched_group *sg;

		int group, j;



		if (cpumask_test_cpu(i, covered))

			continue;



		group = get_group(i, sdd, &sg);

		cpumask_setall(sched_group_mask(sg));

		sg = get_group(i, sdd);



		for_each_cpu(j, span) {

			if (get_group(j, sdd, NULL) != group)

				continue;



			cpumask_set_cpu(j, covered);

			cpumask_set_cpu(j, sched_group_cpus(sg));

		}

		cpumask_or(covered, covered, sched_group_cpus(sg));



		if (!first)

			first = sg;
@@ -904,6 +901,7 @@ build_sched_groups(struct sched_domain *sd, int cpu) 
		last = sg;

	}

	last->next = first;

	sd->groups = first;



	return 0;

}