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comparison src/share/vm/runtime/serviceThread.cpp @ 2211:0cd39a385a72

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Merge.
author Thomas Wuerthinger <thomas.wuerthinger@gmail.com>
date Mon, 21 Feb 2011 19:17:33 +0100
parents bf8517f4e4d0
children 216d916d5c12
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2184:5d801e6b9a80 2211:0cd39a385a72
1 /*
2 * Copyright (c) 2011, 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 "prims/jvmtiImpl.hpp"
31
32 ServiceThread* ServiceThread::_instance = NULL;
33
34 void ServiceThread::initialize() {
35 EXCEPTION_MARK;
36
37 instanceKlassHandle klass (THREAD, SystemDictionary::Thread_klass());
38 instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
39
40 const char* name = JDK_Version::is_gte_jdk17x_version() ?
41 "Service Thread" : "Low Memory Detector";
42
43 Handle string = java_lang_String::create_from_str(name, CHECK);
44
45 // Initialize thread_oop to put it into the system threadGroup
46 Handle thread_group (THREAD, Universe::system_thread_group());
47 JavaValue result(T_VOID);
48 JavaCalls::call_special(&result, thread_oop,
49 klass,
50 vmSymbols::object_initializer_name(),
51 vmSymbols::threadgroup_string_void_signature(),
52 thread_group,
53 string,
54 CHECK);
55
56 {
57 MutexLocker mu(Threads_lock);
58 ServiceThread* thread = new ServiceThread(&service_thread_entry);
59
60 // At this point it may be possible that no osthread was created for the
61 // JavaThread due to lack of memory. We would have to throw an exception
62 // in that case. However, since this must work and we do not allow
63 // exceptions anyway, check and abort if this fails.
64 if (thread == NULL || thread->osthread() == NULL) {
65 vm_exit_during_initialization("java.lang.OutOfMemoryError",
66 "unable to create new native thread");
67 }
68
69 java_lang_Thread::set_thread(thread_oop(), thread);
70 java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
71 java_lang_Thread::set_daemon(thread_oop());
72 thread->set_threadObj(thread_oop());
73
74 Threads::add(thread);
75 Thread::start(thread);
76
77 _instance = thread;
78 }
79 }
80
81 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
82 while (true) {
83 bool sensors_changed = false;
84 bool has_jvmti_events = false;
85 JvmtiDeferredEvent jvmti_event;
86 {
87 // Need state transition ThreadBlockInVM so that this thread
88 // will be handled by safepoint correctly when this thread is
89 // notified at a safepoint.
90
91 // This ThreadBlockInVM object is not also considered to be
92 // suspend-equivalent because ServiceThread is not visible to
93 // external suspension.
94
95 ThreadBlockInVM tbivm(jt);
96
97 MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
98 while (!(sensors_changed = LowMemoryDetector::has_pending_requests()) &&
99 !(has_jvmti_events = JvmtiDeferredEventQueue::has_events())) {
100 // wait until one of the sensors has pending requests, or there is a
101 // pending JVMTI event to post
102 Service_lock->wait(Mutex::_no_safepoint_check_flag);
103 }
104
105 if (has_jvmti_events) {
106 jvmti_event = JvmtiDeferredEventQueue::dequeue();
107 }
108 }
109
110 if (has_jvmti_events) {
111 jvmti_event.post();
112 }
113
114 if (sensors_changed) {
115 LowMemoryDetector::process_sensor_changes(jt);
116 }
117 }
118 }
119
120 bool ServiceThread::is_service_thread(Thread* thread) {
121 return thread == _instance;
122 }