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 JvmtiDeferredEvent* ServiceThread::_jvmti_event = NULL;
50
51 void ServiceThread::initialize() {
52 EXCEPTION_MARK;
53
54 const char* name = "Service Thread";
55 Handle string = java_lang_String::create_from_str(name, CHECK);
56
57 // Initialize thread_oop to put it into the system threadGroup
58 Handle thread_group (THREAD, Universe::system_thread_group());
59 Handle thread_oop = JavaCalls::construct_new_instance(
60 SystemDictionary::Thread_klass(),
61 vmSymbols::threadgroup_string_void_signature(),
62 thread_group,
63 string,
64 CHECK);
65
66 {
67 MutexLocker mu(Threads_lock);
68 ServiceThread* thread = new ServiceThread(&service_thread_entry);
69
70 // At this point it may be possible that no osthread was created for the
71 // JavaThread due to lack of memory. We would have to throw an exception
72 // in that case. However, since this must work and we do not allow
73 // exceptions anyway, check and abort if this fails.
74 if (thread == NULL || thread->osthread() == NULL) {
75 vm_exit_during_initialization("java.lang.OutOfMemoryError",
76 os::native_thread_creation_failed_msg());
77 }
78
79 java_lang_Thread::set_thread(thread_oop(), thread);
80 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
81 java_lang_Thread::set_daemon(thread_oop());
82 thread->set_threadObj(thread_oop());
83 _instance = thread;
84
85 Threads::add(thread);
86 Thread::start(thread);
87 }
88 }
89
90 static void cleanup_oopstorages() {
91 OopStorageSet::Iterator it = OopStorageSet::all_iterator();
92 for ( ; !it.is_end(); ++it) {
93 it->delete_empty_blocks();
94 }
95 }
96
97 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
98 while (true) {
99 bool sensors_changed = false;
100 bool has_jvmti_events = false;
101 bool has_gc_notification_event = false;
102 bool has_dcmd_notification_event = false;
103 bool stringtable_work = false;
104 bool symboltable_work = false;
105 bool resolved_method_table_work = false;
106 bool thread_id_table_work = false;
107 bool protection_domain_table_work = false;
108 bool oopstorage_work = false;
109 bool deflate_idle_monitors = false;
110 JvmtiDeferredEvent jvmti_event;
111 {
112 // Need state transition ThreadBlockInVM so that this thread
113 // will be handled by safepoint correctly when this thread is
114 // notified at a safepoint.
115
116 // This ThreadBlockInVM object is not also considered to be
117 // suspend-equivalent because ServiceThread is not visible to
118 // external suspension.
119
120 ThreadBlockInVM tbivm(jt);
121
122 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
123 // Process all available work on each (outer) iteration, rather than
124 // only the first recognized bit of work, to avoid frequently true early
125 // tests from potentially starving later work. Hence the use of
126 // arithmetic-or to combine results; we don't want short-circuiting.
127 while (((sensors_changed = (!UseNotificationThread && LowMemoryDetector::has_pending_requests())) |
128 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
129 (has_gc_notification_event = (!UseNotificationThread && GCNotifier::has_event())) |
130 (has_dcmd_notification_event = (!UseNotificationThread && DCmdFactory::has_pending_jmx_notification())) |
131 (stringtable_work = StringTable::has_work()) |
132 (symboltable_work = SymbolTable::has_work()) |
133 (resolved_method_table_work = ResolvedMethodTable::has_work()) |
134 (thread_id_table_work = ThreadIdTable::has_work()) |
135 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
136 (oopstorage_work = OopStorage::has_cleanup_work_and_reset()) |
137 (deflate_idle_monitors = ObjectSynchronizer::is_async_deflation_needed())
138 ) == 0) {
139 // Wait until notified that there is some work to do.
140 // If AsyncDeflateIdleMonitors, then we wait for
141 // GuaranteedSafepointInterval so that is_async_deflation_needed()
142 // is checked at the same interval.
143 ml.wait(AsyncDeflateIdleMonitors ? GuaranteedSafepointInterval : 0);
144 }
145
146 if (has_jvmti_events) {
147 // Get the event under the Service_lock
148 jvmti_event = JvmtiDeferredEventQueue::dequeue();
149 _jvmti_event = &jvmti_event;
150 }
151 }
152
153 if (stringtable_work) {
154 StringTable::do_concurrent_work(jt);
155 }
156
157 if (symboltable_work) {
158 SymbolTable::do_concurrent_work(jt);
159 }
160
161 if (has_jvmti_events) {
162 _jvmti_event->post();
163 _jvmti_event = NULL; // reset
164 }
165
166 if (!UseNotificationThread) {
167 if (sensors_changed) {
168 LowMemoryDetector::process_sensor_changes(jt);
169 }
170
171 if(has_gc_notification_event) {
172 GCNotifier::sendNotification(CHECK);
173 }
174
175 if(has_dcmd_notification_event) {
176 DCmdFactory::send_notification(CHECK);
177 }
178 }
179
180 if (resolved_method_table_work) {
181 ResolvedMethodTable::do_concurrent_work(jt);
182 }
183
184 if (thread_id_table_work) {
185 ThreadIdTable::do_concurrent_work(jt);
186 }
187
188 if (protection_domain_table_work) {
189 SystemDictionary::pd_cache_table()->unlink();
190 }
191
192 if (oopstorage_work) {
193 cleanup_oopstorages();
194 }
195
196 if (deflate_idle_monitors) {
197 ObjectSynchronizer::deflate_idle_monitors_using_JT();
198 }
199 }
200 }
201
202 void ServiceThread::oops_do(OopClosure* f, CodeBlobClosure* cf) {
203 JavaThread::oops_do(f, cf);
204 // The ServiceThread "owns" the JVMTI Deferred events, scan them here
205 // to keep them alive until they are processed.
206 if (cf != NULL) {
207 if (_jvmti_event != NULL) {
208 _jvmti_event->oops_do(f, cf);
209 }
210 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
211 JvmtiDeferredEventQueue::oops_do(f, cf);
212 }
213 }
214
215 void ServiceThread::nmethods_do(CodeBlobClosure* cf) {
216 JavaThread::nmethods_do(cf);
217 if (cf != NULL) {
218 if (_jvmti_event != NULL) {
219 _jvmti_event->nmethods_do(cf);
220 }
221 MutexLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
222 JvmtiDeferredEventQueue::nmethods_do(cf);
223 }
224 }