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-rw-r--r--kernel/sched/core.c39
-rw-r--r--kernel/sched/fair.c28
2 files changed, 22 insertions, 45 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index a4ea245f3d85..649c9f876cb1 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6014,11 +6014,6 @@ static void destroy_sched_domains(struct sched_domain *sd, int cpu)
* SD_SHARE_PKG_RESOURCE set (Last Level Cache Domain) for this
* allows us to avoid some pointer chasing select_idle_sibling().
*
- * Iterate domains and sched_groups downward, assigning CPUs to be
- * select_idle_sibling() hw buddy. Cross-wiring hw makes bouncing
- * due to random perturbation self canceling, ie sw buddies pull
- * their counterpart to their CPU's hw counterpart.
- *
* Also keep a unique ID per domain (we use the first cpu number in
* the cpumask of the domain), this allows us to quickly tell if
* two cpus are in the same cache domain, see cpus_share_cache().
@@ -6032,40 +6027,8 @@ static void update_top_cache_domain(int cpu)
int id = cpu;
sd = highest_flag_domain(cpu, SD_SHARE_PKG_RESOURCES);
- if (sd) {
- struct sched_domain *tmp = sd;
- struct sched_group *sg, *prev;
- bool right;
-
- /*
- * Traverse to first CPU in group, and count hops
- * to cpu from there, switching direction on each
- * hop, never ever pointing the last CPU rightward.
- */
- do {
- id = cpumask_first(sched_domain_span(tmp));
- prev = sg = tmp->groups;
- right = 1;
-
- while (cpumask_first(sched_group_cpus(sg)) != id)
- sg = sg->next;
-
- while (!cpumask_test_cpu(cpu, sched_group_cpus(sg))) {
- prev = sg;
- sg = sg->next;
- right = !right;
- }
-
- /* A CPU went down, never point back to domain start. */
- if (right && cpumask_first(sched_group_cpus(sg->next)) == id)
- right = false;
-
- sg = right ? sg->next : prev;
- tmp->idle_buddy = cpumask_first(sched_group_cpus(sg));
- } while ((tmp = tmp->child));
-
+ if (sd)
id = cpumask_first(sched_domain_span(sd));
- }
rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
per_cpu(sd_llc_id, cpu) = id;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 42d9df6a5ca4..96e2b18b6283 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2637,6 +2637,8 @@ static int select_idle_sibling(struct task_struct *p, int target)
int cpu = smp_processor_id();
int prev_cpu = task_cpu(p);
struct sched_domain *sd;
+ struct sched_group *sg;
+ int i;
/*
* If the task is going to be woken-up on this cpu and if it is
@@ -2653,17 +2655,29 @@ static int select_idle_sibling(struct task_struct *p, int target)
return prev_cpu;
/*
- * Otherwise, check assigned siblings to find an elegible idle cpu.
+ * Otherwise, iterate the domains and find an elegible idle cpu.
*/
sd = rcu_dereference(per_cpu(sd_llc, target));
-
for_each_lower_domain(sd) {
- if (!cpumask_test_cpu(sd->idle_buddy, tsk_cpus_allowed(p)))
- continue;
- if (idle_cpu(sd->idle_buddy))
- return sd->idle_buddy;
- }
+ sg = sd->groups;
+ do {
+ if (!cpumask_intersects(sched_group_cpus(sg),
+ tsk_cpus_allowed(p)))
+ goto next;
+ for_each_cpu(i, sched_group_cpus(sg)) {
+ if (!idle_cpu(i))
+ goto next;
+ }
+
+ target = cpumask_first_and(sched_group_cpus(sg),
+ tsk_cpus_allowed(p));
+ goto done;
+next:
+ sg = sg->next;
+ } while (sg != sd->groups);
+ }
+done:
return target;
}