1+ /*
2+ * Copyright (c) 2024, 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. Oracle designates this
8+ * particular file as subject to the "Classpath" exception as provided
9+ * by Oracle in the LICENSE file that accompanied this code.
10+ *
11+ * This code is distributed in the hope that it will be useful, but WITHOUT
12+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14+ * version 2 for more details (a copy is included in the LICENSE file that
15+ * accompanied this code).
16+ *
17+ * You should have received a copy of the GNU General Public License version
18+ * 2 along with this work; if not, write to the Free Software Foundation,
19+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20+ *
21+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22+ * or visit www.oracle.com if you need additional information or have any
23+ * questions.
24+ */
25+ package com .sun .management .internal ;
26+
27+ import java .util .concurrent .Executor ;
28+ import java .util .concurrent .ForkJoinPool ;
29+ import javax .management .ObjectName ;
30+ import jdk .management .VirtualThreadSchedulerMXBean ;
31+ import jdk .internal .access .JavaLangAccess ;
32+ import jdk .internal .access .SharedSecrets ;
33+ import jdk .internal .vm .ContinuationSupport ;
34+ import sun .management .Util ;
35+
36+ /**
37+ * Provides the implementation of the management interface for the JDK's default virtual
38+ * thread scheduler.
39+ */
40+ public class VirtualThreadSchedulerImpls {
41+ private VirtualThreadSchedulerImpls () {
42+ }
43+
44+ public static VirtualThreadSchedulerMXBean create () {
45+ if (ContinuationSupport .isSupported ()) {
46+ return new VirtualThreadSchedulerImpl ();
47+ } else {
48+ return new BoundVirtualThreadSchedulerImpl ();
49+ }
50+ }
51+
52+ /**
53+ * Base implementation of VirtualThreadSchedulerMXBean.
54+ */
55+ private abstract static class BaseVirtualThreadSchedulerImpl
56+ implements VirtualThreadSchedulerMXBean {
57+
58+ abstract void implSetParallelism (int size );
59+
60+ @ Override
61+ public final void setParallelism (int size ) {
62+ Util .checkControlAccess ();
63+ implSetParallelism (size );
64+ }
65+
66+ @ Override
67+ public final ObjectName getObjectName () {
68+ return Util .newObjectName ("jdk.management:type=VirtualThreadScheduler" );
69+ }
70+
71+ @ Override
72+ public String toString () {
73+ var sb = new StringBuilder ("[parallelism=" );
74+ sb .append (getParallelism ());
75+ append (sb , "size" , getPoolSize ());
76+ append (sb , "mounted" , getMountedVirtualThreadCount ());
77+ append (sb , "queued" , getQueuedVirtualThreadCount ());
78+ sb .append (']' );
79+ return sb .toString ();
80+ }
81+
82+ private void append (StringBuilder sb , String name , long value ) {
83+ sb .append (", " ).append (name ).append ('=' );
84+ if (value >= 0 ) {
85+ sb .append (value );
86+ } else {
87+ sb .append ("<unavailable>" );
88+ }
89+ }
90+ }
91+
92+ /**
93+ * Implementation of VirtualThreadSchedulerMXBean when virtual threads are
94+ * implemented with continuations + scheduler.
95+ */
96+ private static final class VirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
97+ /**
98+ * Holder class for scheduler.
99+ */
100+ private static class Scheduler {
101+ private static final Executor scheduler =
102+ SharedSecrets .getJavaLangAccess ().virtualThreadDefaultScheduler ();
103+ static Executor instance () {
104+ return scheduler ;
105+ }
106+ }
107+
108+ @ Override
109+ public int getParallelism () {
110+ if (Scheduler .instance () instanceof ForkJoinPool pool ) {
111+ return pool .getParallelism ();
112+ }
113+ throw new InternalError (); // should not get here
114+ }
115+
116+ @ Override
117+ void implSetParallelism (int size ) {
118+ if (Scheduler .instance () instanceof ForkJoinPool pool ) {
119+ pool .setParallelism (size );
120+ if (pool .getPoolSize () < size ) {
121+ // FJ worker thread creation is on-demand
122+ Thread .startVirtualThread (() -> { });
123+ }
124+
125+ return ;
126+ }
127+ throw new UnsupportedOperationException (); // should not get here
128+ }
129+
130+ @ Override
131+ public int getPoolSize () {
132+ if (Scheduler .instance () instanceof ForkJoinPool pool ) {
133+ return pool .getPoolSize ();
134+ }
135+ return -1 ; // should not get here
136+ }
137+
138+ @ Override
139+ public int getMountedVirtualThreadCount () {
140+ if (Scheduler .instance () instanceof ForkJoinPool pool ) {
141+ return pool .getActiveThreadCount ();
142+ }
143+ return -1 ; // should not get here
144+ }
145+
146+ @ Override
147+ public long getQueuedVirtualThreadCount () {
148+ if (Scheduler .instance () instanceof ForkJoinPool pool ) {
149+ return pool .getQueuedTaskCount () + pool .getQueuedSubmissionCount ();
150+ }
151+ return -1L ; // should not get here
152+ }
153+ }
154+
155+ /**
156+ * Implementation of VirtualThreadSchedulerMXBean when virtual threads are backed
157+ * by platform threads.
158+ */
159+ private static final class BoundVirtualThreadSchedulerImpl extends BaseVirtualThreadSchedulerImpl {
160+ @ Override
161+ public int getParallelism () {
162+ return Integer .MAX_VALUE ;
163+ }
164+
165+ @ Override
166+ void implSetParallelism (int size ) {
167+ throw new UnsupportedOperationException ();
168+ }
169+
170+ @ Override
171+ public int getPoolSize () {
172+ return -1 ;
173+ }
174+
175+ @ Override
176+ public int getMountedVirtualThreadCount () {
177+ return -1 ;
178+ }
179+
180+ @ Override
181+ public long getQueuedVirtualThreadCount () {
182+ return -1L ;
183+ }
184+ }
185+ }
1 commit comments
openjdk-notifier[bot] commentedon Sep 10, 2024
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