1 /*
2 * Copyright (c) 2018, 2018, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23
24
25 package org.graalvm.compiler.hotspot.management;
26
27 import java.lang.management.ManagementFactory;
28 import java.util.ArrayList;
29
30 import javax.management.InstanceAlreadyExistsException;
31 import javax.management.MBeanRegistrationException;
32 import javax.management.MBeanServer;
33 import javax.management.MBeanServerFactory;
34 import javax.management.MalformedObjectNameException;
35 import javax.management.NotCompliantMBeanException;
36 import javax.management.ObjectName;
37
38 import org.graalvm.compiler.debug.TTY;
39 import org.graalvm.compiler.hotspot.HotSpotGraalManagementRegistration;
40 import org.graalvm.compiler.hotspot.HotSpotGraalRuntime;
41 import org.graalvm.compiler.serviceprovider.ServiceProvider;
42
43 /**
44 * Dynamically registers an MBean with the {@link ManagementFactory#getPlatformMBeanServer()}.
45 *
46 * Polling for an active platform MBean server is done by calling
47 * {@link MBeanServerFactory#findMBeanServer(String)} with an argument value of {@code null}. Once
48 * this returns an non-empty list, {@link ManagementFactory#getPlatformMBeanServer()} can be called
49 * to obtain a reference to the platform MBean server instance.
50 */
51 @ServiceProvider(HotSpotGraalManagementRegistration.class)
52 public final class HotSpotGraalManagement implements HotSpotGraalManagementRegistration {
53
54 private HotSpotGraalRuntimeMBean bean;
55 private volatile boolean needsRegistration = true;
56 HotSpotGraalManagement nextDeferred;
57
58 @Override
59 public void initialize(HotSpotGraalRuntime runtime) {
60 if (bean == null) {
61 if (runtime.getManagement() != this) {
62 throw new IllegalArgumentException("Cannot initialize a second management object for runtime " + runtime.getName());
63 }
64 try {
65 String name = runtime.getName().replace(':', '_');
66 ObjectName objectName = new ObjectName("org.graalvm.compiler.hotspot:type=" + name);
67 bean = new HotSpotGraalRuntimeMBean(objectName, runtime);
68 registration.add(this);
69 } catch (MalformedObjectNameException err) {
70 err.printStackTrace(TTY.out);
71 }
72 } else if (bean.getRuntime() != runtime) {
73 throw new IllegalArgumentException("Cannot change the runtime a management interface is associated with");
74 }
75 }
76
77 static final class RegistrationThread extends Thread {
78
79 private MBeanServer platformMBeanServer;
80 private HotSpotGraalManagement deferred;
81
82 RegistrationThread() {
83 super("HotSpotGraalManagement Bean Registration");
84 this.setPriority(Thread.MIN_PRIORITY);
85 this.setDaemon(true);
86 this.start();
87 }
88
89 /**
90 * Poll for active MBean server every 2 seconds.
91 */
92 private static final int POLL_INTERVAL_MS = 2000;
93
94 /**
95 * Adds a {@link HotSpotGraalManagement} to register with an active MBean server when one
96 * becomes available.
97 */
98 synchronized void add(HotSpotGraalManagement e) {
99 if (deferred != null) {
100 e.nextDeferred = deferred;
101 }
102 deferred = e;
103
104 // Notify the registration thread that there is now
105 // a deferred registration to process
106 notify();
107 }
108
109 /**
110 * Processes and clears any deferred registrations.
111 */
112 private void process() {
113 for (HotSpotGraalManagement m = deferred; m != null; m = m.nextDeferred) {
114 HotSpotGraalRuntimeMBean bean = m.bean;
115 if (m.needsRegistration && bean != null) {
116 try {
117 platformMBeanServer.registerMBean(bean, bean.getObjectName());
118 } catch (InstanceAlreadyExistsException | MBeanRegistrationException | NotCompliantMBeanException e) {
119 e.printStackTrace(TTY.out);
120 // Registration failed - don't try again
121 m.bean = null;
122 }
123 m.needsRegistration = false;
124 }
125 }
126 deferred = null;
127 }
128
129 @Override
130 public void run() {
131 while (true) {
132 try {
133 synchronized (this) {
134 // Wait until there are deferred registrations to process
135 while (deferred == null) {
136 wait();
137 }
138 }
139 poll();
140 Thread.sleep(POLL_INTERVAL_MS);
141 } catch (InterruptedException e) {
142 // Be verbose about unexpected interruption and then continue
143 e.printStackTrace(TTY.out);
144 }
145 }
146 }
147
148 /**
149 * Checks for active MBean server and if available, processes deferred registrations.
150 */
151 synchronized void poll() {
152 if (platformMBeanServer == null) {
153 ArrayList<MBeanServer> servers = MBeanServerFactory.findMBeanServer(null);
154 if (!servers.isEmpty()) {
155 platformMBeanServer = ManagementFactory.getPlatformMBeanServer();
156 process();
157 }
158 } else {
159 process();
160 }
161 }
162 }
163
164 private static final RegistrationThread registration = new RegistrationThread();
165
166 @Override
167 public ObjectName poll(boolean sync) {
168 if (sync) {
169 registration.poll();
170 }
171 if (bean == null || needsRegistration) {
172 // initialize() has not been called, it failed or registration failed
173 return null;
174 }
175 return bean.getObjectName();
176 }
177 }