diff --git a/env/io_posix.h b/env/io_posix.h
index 7307b2031..f129668ea 100644
--- a/env/io_posix.h
+++ b/env/io_posix.h
@@ -35,6 +35,12 @@
 #define POSIX_FADV_SEQUENTIAL 2 /* [MC1] expect sequential page refs */
 #define POSIX_FADV_WILLNEED 3   /* [MC1] will need these pages */
 #define POSIX_FADV_DONTNEED 4   /* [MC1] don't need these pages */
+
+#define POSIX_MADV_NORMAL 0     /* [MC1] no further special treatment */
+#define POSIX_MADV_RANDOM 1     /* [MC1] expect random page refs */
+#define POSIX_MADV_SEQUENTIAL 2 /* [MC1] expect sequential page refs */
+#define POSIX_MADV_WILLNEED 3   /* [MC1] will need these pages */
+#define POSIX_MADV_DONTNEED 4   /* [MC1] don't need these pages */
 #endif
 
 namespace ROCKSDB_NAMESPACE {