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-rw-r--r--kernel/sched/core.c9
-rw-r--r--kernel/sched/sched.h25
2 files changed, 28 insertions, 6 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 1a55c842bfbc..a39a08113003 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -43,18 +43,21 @@
DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues);
+#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
/*
* Debugging: various feature bits
+ *
+ * If SCHED_DEBUG is disabled, each compilation unit has its own copy of
+ * sysctl_sched_features, defined in sched.h, to allow constants propagation
+ * at compile time and compiler optimization based on features default.
*/
-
#define SCHED_FEAT(name, enabled) \
(1UL << __SCHED_FEAT_##name) * enabled |
-
const_debug unsigned int sysctl_sched_features =
#include "features.h"
0;
-
#undef SCHED_FEAT
+#endif
/*
* Number of tasks to iterate in a single balance run.
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 58787e3631c7..45ab0bf564e7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1233,8 +1233,6 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
# define const_debug const
#endif
-extern const_debug unsigned int sysctl_sched_features;
-
#define SCHED_FEAT(name, enabled) \
__SCHED_FEAT_##name ,
@@ -1246,6 +1244,13 @@ enum {
#undef SCHED_FEAT
#if defined(CONFIG_SCHED_DEBUG) && defined(HAVE_JUMP_LABEL)
+
+/*
+ * To support run-time toggling of sched features, all the translation units
+ * (but core.c) reference the sysctl_sched_features defined in core.c.
+ */
+extern const_debug unsigned int sysctl_sched_features;
+
#define SCHED_FEAT(name, enabled) \
static __always_inline bool static_branch_##name(struct static_key *key) \
{ \
@@ -1253,13 +1258,27 @@ static __always_inline bool static_branch_##name(struct static_key *key) \
}
#include "features.h"
-
#undef SCHED_FEAT
extern struct static_key sched_feat_keys[__SCHED_FEAT_NR];
#define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x]))
+
#else /* !(SCHED_DEBUG && HAVE_JUMP_LABEL) */
+
+/*
+ * Each translation unit has its own copy of sysctl_sched_features to allow
+ * constants propagation at compile time and compiler optimization based on
+ * features default.
+ */
+#define SCHED_FEAT(name, enabled) \
+ (1UL << __SCHED_FEAT_##name) * enabled |
+static const_debug __maybe_unused unsigned int sysctl_sched_features =
+#include "features.h"
+ 0;
+#undef SCHED_FEAT
+
#define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x))
+
#endif /* SCHED_DEBUG && HAVE_JUMP_LABEL */
extern struct static_key_false sched_numa_balancing;

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