1 /*
2 * Copyright (c) 2012, 2015, 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 "runtime/interfaceSupport.hpp"
27 #include "runtime/javaCalls.hpp"
28 #include "runtime/serviceThread.hpp"
29 #include "runtime/mutexLocker.hpp"
30 #include "runtime/os.hpp"
31 #include "prims/jvmtiImpl.hpp"
32 #include "services/allocationContextService.hpp"
33 #include "services/diagnosticArgument.hpp"
34 #include "services/diagnosticFramework.hpp"
35 #include "services/gcNotifier.hpp"
36 #include "services/lowMemoryDetector.hpp"
37
38 ServiceThread* ServiceThread::_instance = NULL;
39
40 void ServiceThread::initialize() {
41 EXCEPTION_MARK;
42
43 InstanceKlass* klass = SystemDictionary::Thread_klass();
44 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
45
46 const char* name = "Service Thread";
47
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 JavaValue result(T_VOID);
53 JavaCalls::call_special(&result, thread_oop,
54 klass,
55 vmSymbols::object_initializer_name(),
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 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
86 while (true) {
87 bool sensors_changed = false;
88 bool has_jvmti_events = false;
89 bool has_gc_notification_event = false;
90 bool has_dcmd_notification_event = false;
91 bool acs_notify = false;
92 JvmtiDeferredEvent jvmti_event;
93 {
94 // Need state transition ThreadBlockInVM so that this thread
95 // will be handled by safepoint correctly when this thread is
96 // notified at a safepoint.
97
98 // This ThreadBlockInVM object is not also considered to be
99 // suspend-equivalent because ServiceThread is not visible to
100 // external suspension.
101
102 ThreadBlockInVM tbivm(jt);
103
104 MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
105 while (!(sensors_changed = LowMemoryDetector::has_pending_requests()) &&
106 !(has_jvmti_events = JvmtiDeferredEventQueue::has_events()) &&
107 !(has_gc_notification_event = GCNotifier::has_event()) &&
108 !(has_dcmd_notification_event = DCmdFactory::has_pending_jmx_notification()) &&
109 !(acs_notify = AllocationContextService::should_notify())) {
110 // wait until one of the sensors has pending requests, or there is a
111 // pending JVMTI event or JMX GC notification to post
112 Service_lock->wait(Mutex::_no_safepoint_check_flag);
113 }
114
115 if (has_jvmti_events) {
116 jvmti_event = JvmtiDeferredEventQueue::dequeue();
117 }
118 }
119
120 if (has_jvmti_events) {
121 jvmti_event.post();
122 }
123
124 if (sensors_changed) {
125 LowMemoryDetector::process_sensor_changes(jt);
126 }
127
128 if(has_gc_notification_event) {
129 GCNotifier::sendNotification(CHECK);
130 }
131
132 if(has_dcmd_notification_event) {
133 DCmdFactory::send_notification(CHECK);
134 }
135
136 if (acs_notify) {
137 AllocationContextService::notify(CHECK);
138 }
139 }
140 }
141
142 bool ServiceThread::is_service_thread(Thread* thread) {
143 return thread == _instance;
144 }
--- EOF ---