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