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 "runtime/handles.inline.hpp"
31 #include "runtime/interfaceSupport.inline.hpp"
32 #include "runtime/javaCalls.hpp"
33 #include "runtime/jniHandles.hpp"
34 #include "runtime/serviceThread.hpp"
35 #include "runtime/mutexLocker.hpp"
36 #include "runtime/os.hpp"
37 #include "prims/jvmtiImpl.hpp"
38 #include "prims/resolvedMethodTable.hpp"
39 #include "services/diagnosticArgument.hpp"
40 #include "services/diagnosticFramework.hpp"
41 #include "services/gcNotifier.hpp"
42 #include "services/lowMemoryDetector.hpp"
43
44 ServiceThread* ServiceThread::_instance = NULL;
45
46 void ServiceThread::initialize() {
47 EXCEPTION_MARK;
48
49 const char* name = "Service Thread";
50 Handle string = java_lang_String::create_from_str(name, CHECK);
51
52 // Initialize thread_oop to put it into the system threadGroup
53 Handle thread_group (THREAD, Universe::system_thread_group());
54 Handle thread_oop = JavaCalls::construct_new_instance(
55 SystemDictionary::Thread_klass(),
56 vmSymbols::threadgroup_string_void_signature(),
57 thread_group,
58 string,
59 CHECK);
60
61 {
62 MutexLocker mu(Threads_lock);
63 ServiceThread* thread = new ServiceThread(&service_thread_entry);
64
65 // At this point it may be possible that no osthread was created for the
66 // JavaThread due to lack of memory. We would have to throw an exception
67 // in that case. However, since this must work and we do not allow
68 // exceptions anyway, check and abort if this fails.
69 if (thread == NULL || thread->osthread() == NULL) {
70 vm_exit_during_initialization("java.lang.OutOfMemoryError",
71 os::native_thread_creation_failed_msg());
72 }
73
74 java_lang_Thread::set_thread(thread_oop(), thread);
75 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
76 java_lang_Thread::set_daemon(thread_oop());
77 thread->set_threadObj(thread_oop());
78 _instance = thread;
79
80 Threads::add(thread);
81 Thread::start(thread);
82 }
83 }
84
85 static bool needs_oopstorage_cleanup(OopStorage* const* storages,
86 bool* needs_cleanup,
87 size_t size) {
88 bool any_needs_cleanup = false;
89 for (size_t i = 0; i < size; ++i) {
90 assert(!needs_cleanup[i], "precondition");
91 if (storages[i]->needs_delete_empty_blocks()) {
92 needs_cleanup[i] = true;
93 any_needs_cleanup = true;
94 }
95 }
96 return any_needs_cleanup;
97 }
98
99 static void cleanup_oopstorages(OopStorage* const* storages,
100 const bool* needs_cleanup,
101 size_t size) {
102 for (size_t i = 0; i < size; ++i) {
103 if (needs_cleanup[i]) {
104 storages[i]->delete_empty_blocks();
105 }
106 }
107 }
108
109 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
110 OopStorage* const oopstorages[] = {
111 JNIHandles::global_handles(),
112 JNIHandles::weak_global_handles(),
113 StringTable::weak_storage(),
114 SystemDictionary::vm_weak_oop_storage()
115 };
116 const size_t oopstorage_count = ARRAY_SIZE(oopstorages);
117
118 while (true) {
119 bool sensors_changed = false;
120 bool has_jvmti_events = false;
121 bool has_gc_notification_event = false;
122 bool has_dcmd_notification_event = false;
123 bool stringtable_work = false;
124 bool symboltable_work = false;
125 bool resolved_method_table_work = false;
126 bool protection_domain_table_work = false;
127 bool oopstorage_work = false;
128 bool oopstorages_cleanup[oopstorage_count] = {}; // Zero (false) initialize.
129 JvmtiDeferredEvent jvmti_event;
130 {
131 // Need state transition ThreadBlockInVM so that this thread
132 // will be handled by safepoint correctly when this thread is
133 // notified at a safepoint.
134
135 // This ThreadBlockInVM object is not also considered to be
136 // suspend-equivalent because ServiceThread is not visible to
137 // external suspension.
138
139 ThreadBlockInVM tbivm(jt);
140
141 MonitorLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
142 // Process all available work on each (outer) iteration, rather than
143 // only the first recognized bit of work, to avoid frequently true early
144 // tests from potentially starving later work. Hence the use of
145 // arithmetic-or to combine results; we don't want short-circuiting.
146 while (((sensors_changed = LowMemoryDetector::has_pending_requests()) |
147 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) |
148 (has_gc_notification_event = GCNotifier::has_event()) |
149 (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) |
150 (stringtable_work = StringTable::has_work()) |
151 (symboltable_work = SymbolTable::has_work()) |
152 (resolved_method_table_work = ResolvedMethodTable::has_work()) |
153 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work()) |
154 (oopstorage_work = needs_oopstorage_cleanup(oopstorages,
155 oopstorages_cleanup,
156 oopstorage_count)))
157
158 == 0) {
159 // Wait until notified that there is some work to do.
160 ml.wait(Mutex::_no_safepoint_check_flag);
161 }
162
163 if (has_jvmti_events) {
164 jvmti_event = JvmtiDeferredEventQueue::dequeue();
165 }
166 }
167
168 if (stringtable_work) {
169 StringTable::do_concurrent_work(jt);
170 }
171
172 if (symboltable_work) {
173 SymbolTable::do_concurrent_work(jt);
174 }
175
176 if (has_jvmti_events) {
177 jvmti_event.post();
178 }
179
180 if (sensors_changed) {
181 LowMemoryDetector::process_sensor_changes(jt);
182 }
183
184 if(has_gc_notification_event) {
185 GCNotifier::sendNotification(CHECK);
186 }
187
188 if(has_dcmd_notification_event) {
189 DCmdFactory::send_notification(CHECK);
190 }
191
192 if (resolved_method_table_work) {
193 ResolvedMethodTable::unlink();
194 }
195
196 if (protection_domain_table_work) {
197 SystemDictionary::pd_cache_table()->unlink();
198 }
199
200 if (oopstorage_work) {
201 cleanup_oopstorages(oopstorages, oopstorages_cleanup, oopstorage_count);
202 }
203 }
204 }
205
206 bool ServiceThread::is_service_thread(Thread* thread) {
207 return thread == _instance;
208 }