[PATCH 03/19] smart: introduce smart_enabled()

[klamm]

From: Roman Gushchin <klamm@xxxxxxxxxxxxxx>

This patch introduces __smart_enabled static key and smart_enabled()
function, which will be used to check if smart functionality
is enabled.
An ability to turn it on/off will be added later.
By default, __smart_enabled is set to true.

Signed-off-by: Roman Gushchin <klamm@xxxxxxxxxxxxxx>
---
 kernel/sched/rt.c    |  4 ++++
 kernel/sched/sched.h | 13 +++++++++++++
 2 files changed, 17 insertions(+)

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index fed3992..c71b9a3 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -11,6 +11,7 @@
 #include <linux/jump_label.h>
 
 struct static_key __smart_initialized = STATIC_KEY_INIT_FALSE;
+struct static_key __smart_enabled = STATIC_KEY_INIT_TRUE;
 DEFINE_MUTEX(smart_mutex);
 
 DEFINE_PER_CPU_SHARED_ALIGNED(struct smart_core_data, smart_core_data);
@@ -2202,6 +2203,9 @@ void build_smart_topology(void)
 	int cpu;
 	int was_initialized;
 
+	if (!static_key_enabled(&__smart_enabled))
+		return;
+
 	mutex_lock(&smart_mutex);
 
 	was_initialized = static_key_enabled(&__smart_initialized);
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 357736b..7e26454 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -6,6 +6,7 @@
 #include <linux/spinlock.h>
 #include <linux/stop_machine.h>
 #include <linux/tick.h>
+#include <linux/jump_label.h>
 
 #include "cpupri.h"
 #include "cpuacct.h"
@@ -1390,6 +1391,7 @@ struct smart_core_data {
 } ____cacheline_aligned_in_smp;
 
 extern struct static_key __smart_initialized;
+extern struct static_key __smart_enabled;
 
 DECLARE_PER_CPU_SHARED_ALIGNED(struct smart_core_data, smart_core_data);
 
@@ -1400,6 +1402,12 @@ static inline int cpu_core_id(int cpu)
 
 #define smart_data(cpu) per_cpu(smart_core_data, cpu_core_id(cpu))
 
+static inline bool smart_enabled(void)
+{
+	return static_key_false(&__smart_initialized) &&
+		static_key_true(&__smart_enabled);
+}
+
 static inline int core_node_sibling(int cpu)
 {
 	return smart_data(cpu).core_node_sibling;
@@ -1417,4 +1425,9 @@ static inline void build_smart_topology(void)
 {
 }
 
+static inline bool smart_enabled(void)
+{
+	return false;
+}
+
 #endif /* CONFIG_SMART */
-- 
1.9.3

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