diff --git a/kernel/include/ksched.h b/kernel/include/ksched.h
index ff529d06fca..4cc17d5e92e 100644
--- a/kernel/include/ksched.h
+++ b/kernel/include/ksched.h
@@ -119,8 +119,6 @@ static inline bool z_is_prio_lower_or_equal(int prio1, int prio2)
 	return z_is_prio1_lower_than_or_equal_to_prio2(prio1, prio2);
 }
 
-int32_t z_sched_prio_cmp(struct k_thread *thread_1, struct k_thread *thread_2);
-
 static inline bool _is_valid_prio(int prio, void *entry_point)
 {
 	if ((prio == K_IDLE_PRIO) && z_is_idle_thread_entry(entry_point)) {
diff --git a/kernel/include/priority_q.h b/kernel/include/priority_q.h
index febbc6b632c..ed5c839decc 100644
--- a/kernel/include/priority_q.h
+++ b/kernel/include/priority_q.h
@@ -10,9 +10,6 @@
 #include <zephyr/sys/math_extras.h>
 #include <zephyr/sys/dlist.h>
 
-extern int32_t z_sched_prio_cmp(struct k_thread *thread_1,
-	struct k_thread *thread_2);
-
 bool z_priq_rb_lessthan(struct rbnode *a, struct rbnode *b);
 
 /* Dumb Scheduling */
@@ -64,6 +61,47 @@ static ALWAYS_INLINE void z_priq_dumb_init(sys_dlist_t *pq)
 	sys_dlist_init(pq);
 }
 
+/*
+ * Return value same as e.g. memcmp
+ * > 0 -> thread 1 priority  > thread 2 priority
+ * = 0 -> thread 1 priority == thread 2 priority
+ * < 0 -> thread 1 priority  < thread 2 priority
+ * Do not rely on the actual value returned aside from the above.
+ * (Again, like memcmp.)
+ */
+static ALWAYS_INLINE int32_t z_sched_prio_cmp(struct k_thread *thread_1, struct k_thread *thread_2)
+{
+	/* `prio` is <32b, so the below cannot overflow. */
+	int32_t b1 = thread_1->base.prio;
+	int32_t b2 = thread_2->base.prio;
+
+	if (b1 != b2) {
+		return b2 - b1;
+	}
+
+#ifdef CONFIG_SCHED_DEADLINE
+	/* If we assume all deadlines live within the same "half" of
+	 * the 32 bit modulus space (this is a documented API rule),
+	 * then the latest deadline in the queue minus the earliest is
+	 * guaranteed to be (2's complement) non-negative.  We can
+	 * leverage that to compare the values without having to check
+	 * the current time.
+	 */
+	uint32_t d1 = thread_1->base.prio_deadline;
+	uint32_t d2 = thread_2->base.prio_deadline;
+
+	if (d1 != d2) {
+		/* Sooner deadline means higher effective priority.
+		 * Doing the calculation with unsigned types and casting
+		 * to signed isn't perfect, but at least reduces this
+		 * from UB on overflow to impdef.
+		 */
+		return (int32_t)(d2 - d1);
+	}
+#endif /* CONFIG_SCHED_DEADLINE */
+	return 0;
+}
+
 static ALWAYS_INLINE void z_priq_dumb_add(sys_dlist_t *pq, struct k_thread *thread)
 {
 	struct k_thread *t;
diff --git a/kernel/sched.c b/kernel/sched.c
index 76a2113b230..13aeffb99bb 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -45,48 +45,6 @@ BUILD_ASSERT(CONFIG_NUM_COOP_PRIORITIES >= CONFIG_NUM_METAIRQ_PRIORITIES,
 	     "CONFIG_NUM_METAIRQ_PRIORITIES as Meta IRQs are just a special class of cooperative "
 	     "threads.");
 
-/*
- * Return value same as e.g. memcmp
- * > 0 -> thread 1 priority  > thread 2 priority
- * = 0 -> thread 1 priority == thread 2 priority
- * < 0 -> thread 1 priority  < thread 2 priority
- * Do not rely on the actual value returned aside from the above.
- * (Again, like memcmp.)
- */
-int32_t z_sched_prio_cmp(struct k_thread *thread_1,
-	struct k_thread *thread_2)
-{
-	/* `prio` is <32b, so the below cannot overflow. */
-	int32_t b1 = thread_1->base.prio;
-	int32_t b2 = thread_2->base.prio;
-
-	if (b1 != b2) {
-		return b2 - b1;
-	}
-
-#ifdef CONFIG_SCHED_DEADLINE
-	/* If we assume all deadlines live within the same "half" of
-	 * the 32 bit modulus space (this is a documented API rule),
-	 * then the latest deadline in the queue minus the earliest is
-	 * guaranteed to be (2's complement) non-negative.  We can
-	 * leverage that to compare the values without having to check
-	 * the current time.
-	 */
-	uint32_t d1 = thread_1->base.prio_deadline;
-	uint32_t d2 = thread_2->base.prio_deadline;
-
-	if (d1 != d2) {
-		/* Sooner deadline means higher effective priority.
-		 * Doing the calculation with unsigned types and casting
-		 * to signed isn't perfect, but at least reduces this
-		 * from UB on overflow to impdef.
-		 */
-		return (int32_t) (d2 - d1);
-	}
-#endif /* CONFIG_SCHED_DEADLINE */
-	return 0;
-}
-
 static ALWAYS_INLINE void *thread_runq(struct k_thread *thread)
 {
 #ifdef CONFIG_SCHED_CPU_MASK_PIN_ONLY