sched/core: Replace sd_busy/nr_busy_cpus with sched_domain_shared
Move the nr_busy_cpus thing from its hacky sd->parent->groups->sgc
location into the much more natural sched_domain_shared location.
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>
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 8a878b96..98888f1 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1069,6 +1069,7 @@
struct sched_domain_shared {
atomic_t ref;
+ atomic_t nr_busy_cpus;
};
struct sched_domain {
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 97d3c18..26826ea 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5981,14 +5981,14 @@
DEFINE_PER_CPU(struct sched_domain *, sd_llc);
DEFINE_PER_CPU(int, sd_llc_size);
DEFINE_PER_CPU(int, sd_llc_id);
+DEFINE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
DEFINE_PER_CPU(struct sched_domain *, sd_numa);
-DEFINE_PER_CPU(struct sched_domain *, sd_busy);
DEFINE_PER_CPU(struct sched_domain *, sd_asym);
static void update_top_cache_domain(int cpu)
{
+ struct sched_domain_shared *sds = NULL;
struct sched_domain *sd;
- struct sched_domain *busy_sd = NULL;
int id = cpu;
int size = 1;
@@ -5996,13 +5996,13 @@
if (sd) {
id = cpumask_first(sched_domain_span(sd));
size = cpumask_weight(sched_domain_span(sd));
- busy_sd = sd->parent; /* sd_busy */
+ sds = sd->shared;
}
- rcu_assign_pointer(per_cpu(sd_busy, cpu), busy_sd);
rcu_assign_pointer(per_cpu(sd_llc, cpu), sd);
per_cpu(sd_llc_size, cpu) = size;
per_cpu(sd_llc_id, cpu) = id;
+ rcu_assign_pointer(per_cpu(sd_llc_shared, cpu), sds);
sd = lowest_flag_domain(cpu, SD_NUMA);
rcu_assign_pointer(per_cpu(sd_numa, cpu), sd);
@@ -6299,7 +6299,6 @@
return;
update_group_capacity(sd, cpu);
- atomic_set(&sg->sgc->nr_busy_cpus, sg->group_weight);
}
/*
@@ -6546,6 +6545,7 @@
if (sd->flags & SD_SHARE_PKG_RESOURCES) {
sd->shared = *per_cpu_ptr(sdd->sds, sd_id);
atomic_inc(&sd->shared->ref);
+ atomic_set(&sd->shared->nr_busy_cpus, sd_weight);
}
sd->private = sdd;
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 786ef94..15902cd 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -8008,13 +8008,13 @@
int cpu = smp_processor_id();
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
if (!sd || !sd->nohz_idle)
goto unlock;
sd->nohz_idle = 0;
- atomic_inc(&sd->groups->sgc->nr_busy_cpus);
+ atomic_inc(&sd->shared->nr_busy_cpus);
unlock:
rcu_read_unlock();
}
@@ -8025,13 +8025,13 @@
int cpu = smp_processor_id();
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
+ sd = rcu_dereference(per_cpu(sd_llc, cpu));
if (!sd || sd->nohz_idle)
goto unlock;
sd->nohz_idle = 1;
- atomic_dec(&sd->groups->sgc->nr_busy_cpus);
+ atomic_dec(&sd->shared->nr_busy_cpus);
unlock:
rcu_read_unlock();
}
@@ -8258,8 +8258,8 @@
static inline bool nohz_kick_needed(struct rq *rq)
{
unsigned long now = jiffies;
+ struct sched_domain_shared *sds;
struct sched_domain *sd;
- struct sched_group_capacity *sgc;
int nr_busy, cpu = rq->cpu;
bool kick = false;
@@ -8287,11 +8287,13 @@
return true;
rcu_read_lock();
- sd = rcu_dereference(per_cpu(sd_busy, cpu));
- if (sd) {
- sgc = sd->groups->sgc;
- nr_busy = atomic_read(&sgc->nr_busy_cpus);
-
+ sds = rcu_dereference(per_cpu(sd_llc_shared, cpu));
+ if (sds) {
+ /*
+ * XXX: write a coherent comment on why we do this.
+ * See also: http://lkml.kernel.org/r/20111202010832.602203411@sbsiddha-desk.sc.intel.com
+ */
+ nr_busy = atomic_read(&sds->nr_busy_cpus);
if (nr_busy > 1) {
kick = true;
goto unlock;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 420c05d..4fc6e98 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -858,8 +858,8 @@
DECLARE_PER_CPU(struct sched_domain *, sd_llc);
DECLARE_PER_CPU(int, sd_llc_size);
DECLARE_PER_CPU(int, sd_llc_id);
+DECLARE_PER_CPU(struct sched_domain_shared *, sd_llc_shared);
DECLARE_PER_CPU(struct sched_domain *, sd_numa);
-DECLARE_PER_CPU(struct sched_domain *, sd_busy);
DECLARE_PER_CPU(struct sched_domain *, sd_asym);
struct sched_group_capacity {
@@ -871,10 +871,6 @@
unsigned int capacity;
unsigned long next_update;
int imbalance; /* XXX unrelated to capacity but shared group state */
- /*
- * Number of busy cpus in this group.
- */
- atomic_t nr_busy_cpus;
unsigned long cpumask[0]; /* iteration mask */
};
