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
45 ServiceThread* ServiceThread::_instance = NULL;
46
47 void ServiceThread::initialize() {
48 EXCEPTION_MARK;
49
50 const char* name = "Service Thread";
51 Handle string = java_lang_String::create_from_str(name, CHECK);
52
53 // Initialize thread_oop to put it into the system threadGroup
54 Handle thread_group (THREAD, Universe::system_thread_group());
55 Handle thread_oop = JavaCalls::construct_new_instance(
56 SystemDictionary::Thread_klass(),
57 vmSymbols::threadgroup_string_void_signature(),
58 thread_group,
59 string,
60 CHECK);
61
62 {
63 MutexLocker mu(Threads_lock);
64 ServiceThread* thread = new ServiceThread(&service_thread_entry);
65
66 // At this point it may be possible that no osthread was created for the
67 // JavaThread due to lack of memory. We would have to throw an exception
68 // in that case. However, since this must work and we do not allow
69 // exceptions anyway, check and abort if this fails.
70 if (thread == NULL || thread->osthread() == NULL) {
71 vm_exit_during_initialization("java.lang.OutOfMemoryError",
72 os::native_thread_creation_failed_msg());
73 }
74
75 java_lang_Thread::set_thread(thread_oop(), thread);
76 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
77 java_lang_Thread::set_daemon(thread_oop());
78 thread->set_threadObj(thread_oop());
79 _instance = thread;
80
81 Threads::add(thread);
82 Thread::start(thread);
83 }
84 }
85
86 static void cleanup_oopstorages(OopStorage* const* storages, size_t size) {
87 for (size_t i = 0; i < size; ++i) {
88 storages[i]->delete_empty_blocks();
89 }
90 }
91
92 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
93 OopStorage* const oopstorages[] = {
94 JNIHandles::global_handles(),
95 JNIHandles::weak_global_handles(),
96 StringTable::weak_storage(),
97 SystemDictionary::vm_global_oop_storage(),
98 SystemDictionary::vm_weak_oop_storage()
99 };
100 const size_t oopstorage_count = ARRAY_SIZE(oopstorages);
101
102 while (true) {
103 bool sensors_changed = false;
104 bool has_jvmti_events = false;
105 bool has_gc_notification_event = false;
106 bool has_dcmd_notification_event = false;
107 bool stringtable_work = false;
108 bool symboltable_work = false;
109 bool resolved_method_table_work = false;
110 bool protection_domain_table_work = false;
111 bool oopstorage_work = false;
112 JvmtiDeferredEvent jvmti_event;
113 {
114 // Need state transition ThreadBlockInVM so that this thread
115 // will be handled by safepoint correctly when this thread is
116 // notified at a safepoint.
117
118 // This ThreadBlockInVM object is not also considered to be
119 // suspend-equivalent because ServiceThread is not visible to
120 // external suspension.
121
122 ThreadBlockInVM tbivm(jt);
123
124 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
125 // Process all available work on each (outer) iteration, rather than
126 // only the first recognized bit of work, to avoid frequently true early
127 // tests from potentially starving later work. Hence the use of
128 // arithmetic-or to combine results; we don't want short-circuiting.
129 while (((sensors_changed = LowMemoryDetector::has_pending_requests()) |
130 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
131 (has_gc_notification_event = GCNotifier::has_event()) |
132 (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) |
133 (stringtable_work = StringTable::has_work()) |
134 (symboltable_work = SymbolTable::has_work()) |
135 (resolved_method_table_work = ResolvedMethodTable::has_work()) |
136 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
137 (oopstorage_work = OopStorage::has_cleanup_work_and_reset())
138 ) == 0) {
139 // Wait until notified that there is some work to do.
140 ml.wait();
141 }
142
143 if (has_jvmti_events) {
144 jvmti_event = JvmtiDeferredEventQueue::dequeue();
145 }
146 }
147
148 if (stringtable_work) {
149 StringTable::do_concurrent_work(jt);
150 }
151
152 if (symboltable_work) {
153 SymbolTable::do_concurrent_work(jt);
154 }
155
156 if (has_jvmti_events) {
157 jvmti_event.post();
158 }
159
160 if (sensors_changed) {
161 LowMemoryDetector::process_sensor_changes(jt);
162 }
163
164 if(has_gc_notification_event) {
165 GCNotifier::sendNotification(CHECK);
166 }
167
168 if(has_dcmd_notification_event) {
169 DCmdFactory::send_notification(CHECK);
170 }
171
172 if (resolved_method_table_work) {
173 ResolvedMethodTable::do_concurrent_work(jt);
174 }
175
176 if (protection_domain_table_work) {
177 SystemDictionary::pd_cache_table()->unlink();
178 }
179
180 if (oopstorage_work) {
181 cleanup_oopstorages(oopstorages, oopstorage_count);
182 }
183 }
184 }
185
186 bool ServiceThread::is_service_thread(Thread* thread) {
187 return thread == _instance;
188 }