--- a/src/hotspot/os/bsd/os_bsd.cpp	Sun Jan 06 19:49:58 2019 -0500
+++ b/src/hotspot/os/bsd/os_bsd.cpp	Fri Jan 04 17:46:56 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -2256,7 +2256,8 @@
 // not the entire user process, and user level threads are 1:1 mapped to kernel
 // threads. It has always been the case, but could change in the future. For
 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
-// It is only used when ThreadPriorityPolicy=1 and requires root privilege.
+// It is only used when ThreadPriorityPolicy=1 and may require system level permission
+// (e.g., root privilege or CAP_SYS_NICE capability).
 
 #if !defined(__APPLE__)
 int os::java_to_os_priority[CriticalPriority + 1] = {
@@ -2303,14 +2304,12 @@
 
 static int prio_init() {
   if (ThreadPriorityPolicy == 1) {
-    // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
-    // if effective uid is not root. Perhaps, a more elegant way of doing
-    // this is to test CAP_SYS_NICE capability, but that will require libcap.so
     if (geteuid() != 0) {
       if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
-        warning("-XX:ThreadPriorityPolicy requires root privilege on Bsd");
+        warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
+                "e.g., being the root user. If the necessary permission is not " \
+                "possessed, changes to priority will be silently ignored.");
       }
-      ThreadPriorityPolicy = 0;
     }
   }
   if (UseCriticalJavaThreadPriority) {
@@ -2327,6 +2326,7 @@
   return OS_OK;
 #elif defined(__FreeBSD__)
   int ret = pthread_setprio(thread->osthread()->pthread_id(), newpri);
+  return (ret == 0) ? OS_OK : OS_ERR;
 #elif defined(__APPLE__) || defined(__NetBSD__)
   struct sched_param sp;
   int policy;

--- a/src/hotspot/os/linux/os_linux.cpp	Sun Jan 06 19:49:58 2019 -0500
+++ b/src/hotspot/os/linux/os_linux.cpp	Fri Jan 04 17:46:56 2019 +0100
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1999, 2018, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1999, 2019, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -4076,7 +4076,8 @@
 // not the entire user process, and user level threads are 1:1 mapped to kernel
 // threads. It has always been the case, but could change in the future. For
 // this reason, the code should not be used as default (ThreadPriorityPolicy=0).
-// It is only used when ThreadPriorityPolicy=1 and requires root privilege.
+// It is only used when ThreadPriorityPolicy=1 and may require system level permission
+// (e.g., root privilege or CAP_SYS_NICE capability).
 
 int os::java_to_os_priority[CriticalPriority + 1] = {
   19,              // 0 Entry should never be used
@@ -4100,14 +4101,12 @@
 
 static int prio_init() {
   if (ThreadPriorityPolicy == 1) {
-    // Only root can raise thread priority. Don't allow ThreadPriorityPolicy=1
-    // if effective uid is not root. Perhaps, a more elegant way of doing
-    // this is to test CAP_SYS_NICE capability, but that will require libcap.so
     if (geteuid() != 0) {
       if (!FLAG_IS_DEFAULT(ThreadPriorityPolicy)) {
-        warning("-XX:ThreadPriorityPolicy requires root privilege on Linux");
+        warning("-XX:ThreadPriorityPolicy=1 may require system level permission, " \
+                "e.g., being the root user. If the necessary permission is not " \
+                "possessed, changes to priority will be silently ignored.");
       }
-      ThreadPriorityPolicy = 0;
     }
   }
   if (UseCriticalJavaThreadPriority) {

--- a/src/hotspot/share/runtime/globals.hpp	Sun Jan 06 19:49:58 2019 -0500
+++ b/src/hotspot/share/runtime/globals.hpp	Fri Jan 04 17:46:56 2019 +0100
@@ -2049,7 +2049,8 @@
           "    to higher native thread priorities. This policy should be   "\
           "    used with care, as sometimes it can cause performance       "\
           "    degradation in the application and/or the entire system. On "\
-          "    Linux this policy requires root privilege.")                 \
+          "    Linux/BSD/macOS this policy requires root privilege or an   "\
+          "    extended capability.")                                       \
           range(0, 1)                                                       \
                                                                             \
   product(bool, ThreadPriorityVerbose, false,                               \