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