diff --git a/ChangeLog b/ChangeLog
index 87d6317734..3cfd09e55b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,12 @@
+Fri May 29 11:18:58 2015  Eric Wong  <e@80x24.org>
+
+	* ext/socket/ancdata.c (bsock_sendmsg_internal,
+	  bsock_recvmsg_internal):
+	  avoid redundant fcntl on Linux
+	  [ruby-core:69154] [Feature #11145]
+	* ext/socket/init.c (rsock_s_recvfrom_nonblock): ditto
+	* ext/socket/rubysocket.h (MSG_DONTWAIT_RELIABLE): new macro
+
 Fri May 29 10:30:34 2015  Eric Wong  <e@80x24.org>
 
 	* lib/net/resolv.rb (request): use monotonic clock
diff --git a/ext/socket/ancdata.c b/ext/socket/ancdata.c
index 3eaed1cb49..0a94149b08 100644
--- a/ext/socket/ancdata.c
+++ b/ext/socket/ancdata.c
@@ -1277,7 +1277,7 @@ bsock_sendmsg_internal(int argc, VALUE *argv, VALUE sock, int nonblock)
 #endif
 
     rb_io_check_closed(fptr);
-    if (nonblock)
+    if (nonblock && !MSG_DONTWAIT_RELIABLE)
         rb_io_set_nonblock(fptr);
 
     ss = rb_sendmsg(fptr->fd, &mh, flags);
@@ -1595,7 +1595,7 @@ bsock_recvmsg_internal(int argc, VALUE *argv, VALUE sock, int nonblock)
         flags |= MSG_PEEK;
 
     rb_io_check_closed(fptr);
-    if (nonblock)
+    if (nonblock && !MSG_DONTWAIT_RELIABLE)
         rb_io_set_nonblock(fptr);
 
     ss = rb_recvmsg(fptr->fd, &mh, flags);
diff --git a/ext/socket/init.c b/ext/socket/init.c
index 317dd67479..455652d082 100644
--- a/ext/socket/init.c
+++ b/ext/socket/init.c
@@ -211,7 +211,10 @@ rsock_s_recvfrom_nonblock(VALUE sock, int argc, VALUE *argv, enum sock_recv_type
     str = rb_tainted_str_new(0, buflen);
 
     rb_io_check_closed(fptr);
-    rb_io_set_nonblock(fptr);
+
+    if (!MSG_DONTWAIT_RELIABLE)
+	rb_io_set_nonblock(fptr);
+
     len0 = alen;
     slen = recvfrom(fd, RSTRING_PTR(str), buflen, flags, &buf.addr, &alen);
     if (slen != -1 && len0 < alen)
diff --git a/ext/socket/rubysocket.h b/ext/socket/rubysocket.h
index 689a7a8219..359d28ea3d 100644
--- a/ext/socket/rubysocket.h
+++ b/ext/socket/rubysocket.h
@@ -407,9 +407,20 @@ NORETURN(void rsock_sys_fail_raddrinfo_or_sockaddr(const char *, VALUE addr, VAL
 #if defined(__linux__)
 static inline int rsock_maybe_fd_writable(int fd) { return 1; }
 static inline void rsock_maybe_wait_fd(int fd) { }
+#  ifdef MSG_DONTWAIT
+#    define MSG_DONTWAIT_RELIABLE 1
+#  endif
 #else /* some systems (mswin/mingw) need these.  ref: r36946 */
 #  define rsock_maybe_fd_writable(fd) rb_thread_fd_writable((fd))
 #  define rsock_maybe_wait_fd(fd) rb_thread_wait_fd((fd))
 #endif
 
+/*
+ * some OSes may support MSG_DONTWAIT inconsistently depending on socket
+ * type, we only expect Linux to support it consistently for all socket types.
+ */
+#ifndef MSG_DONTWAIT_RELIABLE
+#  define MSG_DONTWAIT_RELIABLE 0
+#endif
+
 #endif