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 }