[PATCH V3 02/10] sched/topology: Adding function partition_sched_domains_locked()

Mathieu Poirier
2018-02-13T20:33:00Z

Introducing function partition_sched_domains_locked() by taking
the mutex locking code out of the original function. That way
the work done by partition_sched_domains_locked() can be reused
without dropping the mutex lock.

No change of functionality is introduced by this patch.

Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
include/linux/sched/topology.h | 10 ++++++++++
kernel/sched/topology.c | 18 ++++++++++++++----
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/include/linux/sched/topology.h b/include/linux/sched/topology.h
index 26347741ba50..57997caf61b6 100644
--- a/include/linux/sched/topology.h
+++ b/include/linux/sched/topology.h
@@ -162,6 +162,10 @@ static inline struct cpumask *sched_domain_span(struct sched_domain *sd)
return to_cpumask(sd->span);
}

+extern void partition_sched_domains_locked(int ndoms_new,
+ cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new);
+
extern void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new);

@@ -207,6 +211,12 @@ extern void set_sched_topology(struct sched_domain_topology_level *tl);
struct sched_domain_attr;

static inline void
+partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new)
+{
+}
+
+static inline void
partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
struct sched_domain_attr *dattr_new)
{
diff --git a/kernel/sched/topology.c b/kernel/sched/topology.c
index 7c744c7425ec..eee721da40fb 100644
--- a/kernel/sched/topology.c
+++ b/kernel/sched/topology.c
@@ -1855,16 +1855,16 @@ static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur,
* ndoms_new == 0 is a special case for destroying existing domains,
* and it will not create the default domain.
*
- * Call with hotplug lock held
+ * Call with hotplug lock and sched_domains_mutex held
*/
-void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
- struct sched_domain_attr *dattr_new)
+void partition_sched_domains_locked(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new)
{
int i, j, n;
int new_topology;

lockdep_assert_cpus_held();
- mutex_lock(&sched_domains_mutex);
+ lockdep_assert_held(&sched_domains_mutex);

/* Always unregister in case we don't destroy any domains: */
unregister_sched_domain_sysctl();
@@ -1929,7 +1929,17 @@ void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
ndoms_cur = ndoms_new;

register_sched_domain_sysctl();
+}

+/*
+ * Call with hotplug lock held
+ */
+void partition_sched_domains(int ndoms_new, cpumask_var_t doms_new[],
+ struct sched_domain_attr *dattr_new)
+{
+ lockdep_assert_cpus_held();
+ mutex_lock(&sched_domains_mutex);
+ partition_sched_domains_locked(ndoms_new, doms_new, dattr_new);
mutex_unlock(&sched_domains_mutex);
}

--
2.7.4