1 /*
2 * Copyright (c) 2012, 2019, 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 #include "precompiled.hpp"
26 #include "classfile/protectionDomainCache.hpp"
27 #include "classfile/stringTable.hpp"
28 #include "classfile/symbolTable.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "gc/shared/oopStorage.hpp"
31 #include "gc/shared/oopStorageSet.hpp"
32 #include "memory/universe.hpp"
33 #include "runtime/handles.inline.hpp"
34 #include "runtime/interfaceSupport.inline.hpp"
35 #include "runtime/javaCalls.hpp"
36 #include "runtime/jniHandles.hpp"
37 #include "runtime/serviceThread.hpp"
38 #include "runtime/mutexLocker.hpp"
39 #include "runtime/os.hpp"
40 #include "prims/jvmtiImpl.hpp"
41 #include "prims/resolvedMethodTable.hpp"
42 #include "services/diagnosticArgument.hpp"
43 #include "services/diagnosticFramework.hpp"
44 #include "services/gcNotifier.hpp"
45 #include "services/lowMemoryDetector.hpp"
46 #include "services/threadIdTable.hpp"
47
48 ServiceThread* ServiceThread::_instance = NULL;
49
50 void ServiceThread::initialize() {
51 EXCEPTION_MARK;
52
53 const char* name = "Service Thread";
54 Handle string = java_lang_String::create_from_str(name, CHECK);
55
56 // Initialize thread_oop to put it into the system threadGroup
57 Handle thread_group (THREAD, Universe::system_thread_group());
58 Handle thread_oop = JavaCalls::construct_new_instance(
59 SystemDictionary::Thread_klass(),
60 vmSymbols::threadgroup_string_void_signature(),
61 thread_group,
62 string,
63 CHECK);
64
65 {
66 MutexLocker mu(Threads_lock);
67 ServiceThread* thread = new ServiceThread(&service_thread_entry);
68
69 // At this point it may be possible that no osthread was created for the
70 // JavaThread due to lack of memory. We would have to throw an exception
71 // in that case. However, since this must work and we do not allow
72 // exceptions anyway, check and abort if this fails.
73 if (thread == NULL || thread->osthread() == NULL) {
74 vm_exit_during_initialization("java.lang.OutOfMemoryError",
75 os::native_thread_creation_failed_msg());
76 }
77
78 java_lang_Thread::set_thread(thread_oop(), thread);
79 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
80 java_lang_Thread::set_daemon(thread_oop());
81 thread->set_threadObj(thread_oop());
82 _instance = thread;
83
84 Threads::add(thread);
85 Thread::start(thread);
86 }
87 }
88
89 static void cleanup_oopstorages() {
90 OopStorageSet::Iterator it = OopStorageSet::all_iterator();
91 for ( ; !it.is_end(); ++it) {
92 it->delete_empty_blocks();
93 }
94 }
95
96 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
97 while (true) {
98 bool sensors_changed = false;
99 bool has_jvmti_events = false;
100 bool has_gc_notification_event = false;
101 bool has_dcmd_notification_event = false;
102 bool stringtable_work = false;
103 bool symboltable_work = false;
104 bool resolved_method_table_work = false;
105 bool thread_id_table_work = false;
106 bool protection_domain_table_work = false;
107 bool oopstorage_work = false;
108 bool deflate_idle_monitors = false;
109 JvmtiDeferredEvent jvmti_event;
110 {
111 // Need state transition ThreadBlockInVM so that this thread
112 // will be handled by safepoint correctly when this thread is
113 // notified at a safepoint.
114
115 // This ThreadBlockInVM object is not also considered to be
116 // suspend-equivalent because ServiceThread is not visible to
117 // external suspension.
118
119 ThreadBlockInVM tbivm(jt);
120
121 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
122 // Process all available work on each (outer) iteration, rather than
123 // only the first recognized bit of work, to avoid frequently true early
124 // tests from potentially starving later work. Hence the use of
125 // arithmetic-or to combine results; we don't want short-circuiting.
126 while (((sensors_changed = (!UseNotificationThread && LowMemoryDetector::has_pending_requests())) |
127 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
128 (has_gc_notification_event = (!UseNotificationThread && GCNotifier::has_event())) |
129 (has_dcmd_notification_event = (!UseNotificationThread && DCmdFactory::has_pending_jmx_notification())) |
130 (stringtable_work = StringTable::has_work()) |
131 (symboltable_work = SymbolTable::has_work()) |
132 (resolved_method_table_work = ResolvedMethodTable::has_work()) |
133 (thread_id_table_work = ThreadIdTable::has_work()) |
134 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
135 (oopstorage_work = OopStorage::has_cleanup_work_and_reset()) |
136 (deflate_idle_monitors = ObjectSynchronizer::is_async_deflation_needed())
137 ) == 0) {
138 // Wait until notified that there is some work to do.
139 // If AsyncDeflateIdleMonitors, then we wait for
140 // GuaranteedSafepointInterval so that is_async_deflation_needed()
141 // is checked at the same interval.
142 ml.wait(AsyncDeflateIdleMonitors ? GuaranteedSafepointInterval : 0);
143 }
144
145 if (has_jvmti_events) {
146 jvmti_event = JvmtiDeferredEventQueue::dequeue();
147 }
148 }
149
150 if (stringtable_work) {
151 StringTable::do_concurrent_work(jt);
152 }
153
154 if (symboltable_work) {
155 SymbolTable::do_concurrent_work(jt);
156 }
157
158 if (has_jvmti_events) {
159 jvmti_event.post();
160 }
161
162 if (!UseNotificationThread) {
163 if (sensors_changed) {
164 LowMemoryDetector::process_sensor_changes(jt);
165 }
166
167 if(has_gc_notification_event) {
168 GCNotifier::sendNotification(CHECK);
169 }
170
171 if(has_dcmd_notification_event) {
172 DCmdFactory::send_notification(CHECK);
173 }
174 }
175
176 if (resolved_method_table_work) {
177 ResolvedMethodTable::do_concurrent_work(jt);
178 }
179
180 if (thread_id_table_work) {
181 ThreadIdTable::do_concurrent_work(jt);
182 }
183
184 if (protection_domain_table_work) {
185 SystemDictionary::pd_cache_table()->unlink();
186 }
187
188 if (oopstorage_work) {
189 cleanup_oopstorages();
190 }
191
192 if (deflate_idle_monitors) {
193 ObjectSynchronizer::deflate_idle_monitors_using_JT();
194 }
195 }
196 }
197
198 bool ServiceThread::is_service_thread(Thread* thread) {
199 return thread == _instance;
200 }