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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: Peter 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: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Peter Zijlstra 2017-05-03 14:18:06 +02:00 committed by Ingo Molnar
parent 35a566e6e8
commit 0c0e776a9b
1 changed files with 22 additions and 24 deletions
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46
kernel/sched/topology.c
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@ -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);
/* For claim_allocations: */
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;
}