+
+/*
+ * Wake-up any waiting defer thread. Called from many concurrent threads.
+ */
+void wake_up_defer(void)
+{
+ if (unlikely(atomic_read(&defer_thread_futex) == -1))
+ atomic_set(&defer_thread_futex, 0);
+ futex(&defer_thread_futex, FUTEX_WAKE,
+ 0, NULL, NULL, 0);
+}
+
+/*
+ * Defer thread waiting. Single thread.
+ */
+static void wait_defer(void)
+{
+ atomic_dec(&defer_thread_futex);
+ if (atomic_read(&defer_thread_futex) == -1)
+ futex(&defer_thread_futex, FUTEX_WAIT, -1,
+ NULL, NULL, 0);
+}