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_weak_oop_storage() 98 }; 99 const size_t oopstorage_count = ARRAY_SIZE(oopstorages); 100 101 while (true) { 102 bool sensors_changed = false; 103 bool has_jvmti_events = false; 104 bool has_gc_notification_event = false; 105 bool has_dcmd_notification_event = false; 106 bool stringtable_work = false; 107 bool symboltable_work = false; 108 bool resolved_method_table_work = false; 109 bool protection_domain_table_work = false; 110 bool oopstorage_work = false; 111 bool deflate_idle_monitors = 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 (deflate_idle_monitors = ObjectSynchronizer::is_async_deflation_needed()) 139 ) == 0) { 140 // Wait until notified that there is some work to do. 141 // If AsyncDeflateIdleMonitors, then we wait for 142 // GuaranteedSafepointInterval so that is_async_deflation_needed() 143 // is checked at the same interval. 144 ml.wait(AsyncDeflateIdleMonitors ? GuaranteedSafepointInterval : 0); 145 } 146 147 if (has_jvmti_events) { 148 jvmti_event = JvmtiDeferredEventQueue::dequeue(); 149 } 150 } 151 152 if (stringtable_work) { 153 StringTable::do_concurrent_work(jt); 154 } 155 156 if (symboltable_work) { 157 SymbolTable::do_concurrent_work(jt); 158 } 159 160 if (has_jvmti_events) { 161 jvmti_event.post(); 162 } 163 164 if (sensors_changed) { 165 LowMemoryDetector::process_sensor_changes(jt); 166 } 167 168 if(has_gc_notification_event) { 169 GCNotifier::sendNotification(CHECK); 170 } 171 172 if(has_dcmd_notification_event) { 173 DCmdFactory::send_notification(CHECK); 174 } 175 176 if (resolved_method_table_work) { 177 ResolvedMethodTable::do_concurrent_work(jt); 178 } 179 180 if (protection_domain_table_work) { 181 SystemDictionary::pd_cache_table()->unlink(); 182 } 183 184 if (oopstorage_work) { 185 cleanup_oopstorages(oopstorages, oopstorage_count); 186 } 187 188 if (deflate_idle_monitors) { 189 // Deflate any global idle monitors. 190 ObjectSynchronizer::deflate_global_idle_monitors_using_JT(); 191 192 // deflate_per_thread_idle_monitors_using_JT() is called by 193 // each JavaThread from ObjectSynchronizer::omAlloc() as needed. 194 int count = 0; 195 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *jt = jtiwh.next(); ) { 196 if (jt->omInUseCount > 0) { 197 // This JavaThread is using monitors so mark it. 198 jt->omShouldDeflateIdleMonitors = true; 199 count++; 200 } 201 } 202 if (count > 0) { 203 log_debug(monitorinflation)("requesting async deflation of idle monitors for %d thread(s).", count); 204 } 205 // The ServiceThread's async deflation request has been processed. 206 ObjectSynchronizer::set_is_async_deflation_requested(false); 207 208 // The global in-use list was handled above, but the request won't 209 // be complete until the JavaThreads have handled their in-use 210 // lists. This is the nature of an async deflation request. 211 } 212 } 213 } 214 215 bool ServiceThread::is_service_thread(Thread* thread) { 216 return thread == _instance; 217 }