#define __NR_fadvise64 413
#endif
-#define nop do { } while (0)
-#define read_barrier() __asm__ __volatile__("mb": : :"memory")
+#define nop do { } while (0)
+#define read_barrier() __asm__ __volatile__("mb": : :"memory")
+#define writer_barrier() __asm__ __volatile__("wmb": : :"memory")
#endif