1 /* 2 * Copyright (c) 2012, 2018, 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/interfaceSupport.inline.hpp" 31 #include "runtime/javaCalls.hpp" 32 #include "runtime/serviceThread.hpp" 33 #include "runtime/mutexLocker.hpp" 34 #include "runtime/os.hpp" 35 #include "prims/jvmtiImpl.hpp" 36 #include "prims/resolvedMethodTable.hpp" 37 #include "services/diagnosticArgument.hpp" 38 #include "services/diagnosticFramework.hpp" 39 #include "services/gcNotifier.hpp" 40 #include "services/lowMemoryDetector.hpp" 41 42 ServiceThread* ServiceThread::_instance = NULL; 43 44 void ServiceThread::initialize() { 45 EXCEPTION_MARK; 46 47 const char* name = "Service Thread"; 48 Handle string = java_lang_String::create_from_str(name, CHECK); 49 50 // Initialize thread_oop to put it into the system threadGroup 51 Handle thread_group (THREAD, Universe::system_thread_group()); 52 Handle thread_oop = JavaCalls::construct_new_instance( 53 SystemDictionary::Thread_klass(), 54 vmSymbols::threadgroup_string_void_signature(), 55 thread_group, 56 string, 57 CHECK); 58 59 { 60 MutexLocker mu(Threads_lock); 61 ServiceThread* thread = new ServiceThread(&service_thread_entry); 62 63 // At this point it may be possible that no osthread was created for the 64 // JavaThread due to lack of memory. We would have to throw an exception 65 // in that case. However, since this must work and we do not allow 66 // exceptions anyway, check and abort if this fails. 67 if (thread == NULL || thread->osthread() == NULL) { 68 vm_exit_during_initialization("java.lang.OutOfMemoryError", 69 os::native_thread_creation_failed_msg()); 70 } 71 72 java_lang_Thread::set_thread(thread_oop(), thread); 73 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority); 74 java_lang_Thread::set_daemon(thread_oop()); 75 thread->set_threadObj(thread_oop()); 76 _instance = thread; 77 78 Threads::add(thread); 79 Thread::start(thread); 80 } 81 } 82 83 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) { 84 while (true) { 85 bool sensors_changed = false; 86 bool has_jvmti_events = false; 87 bool has_gc_notification_event = false; 88 bool has_dcmd_notification_event = false; 89 bool stringtable_work = false; 90 bool symboltable_work = false; 91 bool resolved_method_table_work = false; 92 bool protection_domain_table_work = false; 93 JvmtiDeferredEvent jvmti_event; 94 { 95 // Need state transition ThreadBlockInVM so that this thread 96 // will be handled by safepoint correctly when this thread is 97 // notified at a safepoint. 98 99 // This ThreadBlockInVM object is not also considered to be 100 // suspend-equivalent because ServiceThread is not visible to 101 // external suspension. 102 103 ThreadBlockInVM tbivm(jt); 104 105 MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag); 106 // Use arithmetic-or to combine results; we don't want short-circuiting. 107 while (((sensors_changed = LowMemoryDetector::has_pending_requests()) | 108 (has_jvmti_events = JvmtiDeferredEventQueue::has_events()) | 109 (has_gc_notification_event = GCNotifier::has_event()) | 110 (has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) | 111 (stringtable_work = StringTable::has_work()) | 112 (symboltable_work = SymbolTable::has_work()) | 113 (resolved_method_table_work = ResolvedMethodTable::has_work()) | 114 (protection_domain_table_work = SystemDictionary::pd_cache_table()->has_work())) 115 == 0) { 116 // Wait until notified that there is some work to do. 117 Service_lock->wait(Mutex::_no_safepoint_check_flag); 118 } 119 120 if (has_jvmti_events) { 121 jvmti_event = JvmtiDeferredEventQueue::dequeue(); 122 } 123 } 124 125 if (stringtable_work) { 126 StringTable::do_concurrent_work(jt); 127 } 128 129 if (symboltable_work) { 130 SymbolTable::do_concurrent_work(jt); 131 } 132 133 if (has_jvmti_events) { 134 jvmti_event.post(); 135 } 136 137 if (sensors_changed) { 138 LowMemoryDetector::process_sensor_changes(jt); 139 } 140 141 if(has_gc_notification_event) { 142 GCNotifier::sendNotification(CHECK); 143 } 144 145 if(has_dcmd_notification_event) { 146 DCmdFactory::send_notification(CHECK); 147 } 148 149 if (resolved_method_table_work) { 150 ResolvedMethodTable::unlink(); 151 } 152 153 if (protection_domain_table_work) { 154 SystemDictionary::pd_cache_table()->unlink(); 155 } 156 } 157 } 158 159 bool ServiceThread::is_service_thread(Thread* thread) { 160 return thread == _instance; 161 }