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 bool needs_oopstorage_cleanup(OopStorage* const* storages,
88 bool* needs_cleanup,
89 size_t size) {
90 bool any_needs_cleanup = false;
91 for (size_t i = 0; i < size; ++i) {
92 assert(!needs_cleanup[i], "precondition");
93 if (storages[i]->needs_delete_empty_blocks()) {
94 needs_cleanup[i] = true;
95 any_needs_cleanup = true;
96 }
97 }
98 return any_needs_cleanup;
99 }
100
101 static void cleanup_oopstorages(OopStorage* const* storages,
102 const bool* needs_cleanup,
103 size_t size) {
104 for (size_t i = 0; i < size; ++i) {
105 if (needs_cleanup[i]) {
106 storages[i]->delete_empty_blocks();
107 }
108 }
109 }
110
111 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
112 OopStorage* const oopstorages[] = {
113 JNIHandles::global_handles(),
114 JNIHandles::weak_global_handles(),
115 StringTable::weak_storage(),
116 SystemDictionary::vm_weak_oop_storage()
117 };
118 const size_t oopstorage_count = ARRAY_SIZE(oopstorages);
119
120 while (true) {
121 bool sensors_changed = false;
122 bool has_jvmti_events = false;
123 bool has_gc_notification_event = false;
124 bool has_dcmd_notification_event = false;
125 bool stringtable_work = false;
126 bool symboltable_work = false;
127 bool resolved_method_table_work = false;
128 bool thread_table_work = false;
129 bool protection_domain_table_work = false;
130 bool oopstorage_work = false;
131 bool oopstorages_cleanup[oopstorage_count] = {}; // Zero (false) initialize.
132 JvmtiDeferredEvent jvmti_event;
133 {
134 // Need state transition ThreadBlockInVM so that this thread
135 // will be handled by safepoint correctly when this thread is
136 // notified at a safepoint.
137
138 // This ThreadBlockInVM object is not also considered to be
139 // suspend-equivalent because ServiceThread is not visible to
140 // external suspension.
141
142 ThreadBlockInVM tbivm(jt);
143
144 MonitorLocker ml(Service_lock, Mutex::_no_safepoint_check_flag);
145 // Process all available work on each (outer) iteration, rather than
146 // only the first recognized bit of work, to avoid frequently true early
147 // tests from potentially starving later work. Hence the use of
148 // arithmetic-or to combine results; we don't want short-circuiting.
149 while (((sensors_changed = LowMemoryDetector::has_pending_requests()) |
150 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
151 (has_gc_notification_event = GCNotifier::has_event()) |
152 (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) |
153 (stringtable_work = StringTable::has_work()) |
154 (symboltable_work = SymbolTable::has_work()) |
155 (resolved_method_table_work = ResolvedMethodTable::has_work()) |
156 (thread_table_work = ThreadTable::has_work()) |
157 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
158 (oopstorage_work = needs_oopstorage_cleanup(oopstorages,
159 oopstorages_cleanup,
160 oopstorage_count)))
161
162 == 0) {
163 // Wait until notified that there is some work to do.
164 ml.wait();
165 }
166
167 if (has_jvmti_events) {
168 jvmti_event = JvmtiDeferredEventQueue::dequeue();
169 }
170 }
171
172 if (stringtable_work) {
173 StringTable::do_concurrent_work(jt);
174 }
175
176 if (symboltable_work) {
177 SymbolTable::do_concurrent_work(jt);
178 }
179
180 if (has_jvmti_events) {
181 jvmti_event.post();
182 }
183
184 if (sensors_changed) {
185 LowMemoryDetector::process_sensor_changes(jt);
186 }
187
188 if(has_gc_notification_event) {
189 GCNotifier::sendNotification(CHECK);
190 }
191
192 if(has_dcmd_notification_event) {
193 DCmdFactory::send_notification(CHECK);
194 }
195
196 if (resolved_method_table_work) {
197 ResolvedMethodTable::do_concurrent_work(jt);
198 }
199
200 if (thread_table_work) {
201 ThreadTable::do_concurrent_work(jt);
202 }
203
204 if (protection_domain_table_work) {
205 SystemDictionary::pd_cache_table()->unlink();
206 }
207
208 if (oopstorage_work) {
209 cleanup_oopstorages(oopstorages, oopstorages_cleanup, oopstorage_count);
210 }
211 }
212 }
213
214 bool ServiceThread::is_service_thread(Thread* thread) {
215 return thread == _instance;
216 }