kernel: Re-order should_preempt() checks

Re-orders the checks in should_preempt() tests so that the
z_is_thread_timeout_active() check is done last.

This change has been observed to give a +7% performance boost on
the thread_metric benchmark's preemptive scheduling test.

Signed-off-by: Peter Mitsis <[email protected]>

kernel/include/kthread.h

@@ -204,6 +204,13 @@ static ALWAYS_INLINE bool should_preempt(struct k_thread *thread,
 		return true;
 	}
 
+	/* Otherwise we have to be running a preemptible thread or
+	 * switching to a metairq
+	 */
+	if (thread_is_preemptible(_current) || thread_is_metairq(thread)) {
+		return true;
+	}
+
 	/* Edge case on ARM where a thread can be pended out of an
 	 * interrupt handler before the "synchronous" swap starts
 	 * context switching.  Platforms with atomic swap can never
@@ -214,13 +221,6 @@ static ALWAYS_INLINE bool should_preempt(struct k_thread *thread,
 		return true;
 	}
 
-	/* Otherwise we have to be running a preemptible thread or
-	 * switching to a metairq
-	 */
-	if (thread_is_preemptible(_current) || thread_is_metairq(thread)) {
-		return true;
-	}
-
 	return false;
 }