+/* Number of busy-loop attempts before waiting on futex. */
+#define FUTEX_WAIT_ATTEMPTS 1000
+
+enum futex_wait_state {
+ /* FUTEX_WAIT_WAITING is compared directly (futex() compares it). */
+ FUTEX_WAIT_WAITING = 0,
+ /* non-zero are used as masks. */
+ FUTEX_WAIT_WAKEUP = (1 << 0),
+ FUTEX_WAIT_RUNNING = (1 << 1),
+ FUTEX_WAIT_TEARDOWN = (1 << 2),
+};
+