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-rw-r--r--include/linux/sched.h41
-rw-r--r--kernel/sched/core.c12
2 files changed, 53 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d5e3c00b74e1..67f06f72c50e 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -2117,6 +2117,47 @@ static inline void cond_resched_rcu(void)
#endif
}
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+extern bool preempt_model_none(void);
+extern bool preempt_model_voluntary(void);
+extern bool preempt_model_full(void);
+
+#else
+
+static inline bool preempt_model_none(void)
+{
+ return IS_ENABLED(CONFIG_PREEMPT_NONE);
+}
+static inline bool preempt_model_voluntary(void)
+{
+ return IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY);
+}
+static inline bool preempt_model_full(void)
+{
+ return IS_ENABLED(CONFIG_PREEMPT);
+}
+
+#endif
+
+static inline bool preempt_model_rt(void)
+{
+ return IS_ENABLED(CONFIG_PREEMPT_RT);
+}
+
+/*
+ * Does the preemption model allow non-cooperative preemption?
+ *
+ * For !CONFIG_PREEMPT_DYNAMIC kernels this is an exact match with
+ * CONFIG_PREEMPTION; for CONFIG_PREEMPT_DYNAMIC this doesn't work as the
+ * kernel is *built* with CONFIG_PREEMPTION=y but may run with e.g. the
+ * PREEMPT_NONE model.
+ */
+static inline bool preempt_model_preemptible(void)
+{
+ return preempt_model_full() || preempt_model_rt();
+}
+
/*
* Does a critical section need to be broken due to another
* task waiting?: (technically does not depend on CONFIG_PREEMPTION,
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d575b4914925..068c088e9584 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8409,6 +8409,18 @@ static void __init preempt_dynamic_init(void)
}
}
+#define PREEMPT_MODEL_ACCESSOR(mode) \
+ bool preempt_model_##mode(void) \
+ { \
+ WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
+ return preempt_dynamic_mode == preempt_dynamic_##mode; \
+ } \
+ EXPORT_SYMBOL_GPL(preempt_model_##mode)
+
+PREEMPT_MODEL_ACCESSOR(none);
+PREEMPT_MODEL_ACCESSOR(voluntary);
+PREEMPT_MODEL_ACCESSOR(full);
+
#else /* !CONFIG_PREEMPT_DYNAMIC */
static inline void preempt_dynamic_init(void) { }