1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/runtime/serviceThread.cpp Wed Feb 02 14:38:01 2011 -0500
1.3 @@ -0,0 +1,122 @@
1.4 +/*
1.5 + * Copyright (c) 2011, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#include "precompiled.hpp"
1.29 +#include "runtime/interfaceSupport.hpp"
1.30 +#include "runtime/javaCalls.hpp"
1.31 +#include "runtime/serviceThread.hpp"
1.32 +#include "runtime/mutexLocker.hpp"
1.33 +#include "prims/jvmtiImpl.hpp"
1.34 +
1.35 +ServiceThread* ServiceThread::_instance = NULL;
1.36 +
1.37 +void ServiceThread::initialize() {
1.38 + EXCEPTION_MARK;
1.39 +
1.40 + instanceKlassHandle klass (THREAD, SystemDictionary::Thread_klass());
1.41 + instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);
1.42 +
1.43 + const char* name = JDK_Version::is_gte_jdk17x_version() ?
1.44 + "Service Thread" : "Low Memory Detector";
1.45 +
1.46 + Handle string = java_lang_String::create_from_str(name, CHECK);
1.47 +
1.48 + // Initialize thread_oop to put it into the system threadGroup
1.49 + Handle thread_group (THREAD, Universe::system_thread_group());
1.50 + JavaValue result(T_VOID);
1.51 + JavaCalls::call_special(&result, thread_oop,
1.52 + klass,
1.53 + vmSymbols::object_initializer_name(),
1.54 + vmSymbols::threadgroup_string_void_signature(),
1.55 + thread_group,
1.56 + string,
1.57 + CHECK);
1.58 +
1.59 + {
1.60 + MutexLocker mu(Threads_lock);
1.61 + ServiceThread* thread = new ServiceThread(&service_thread_entry);
1.62 +
1.63 + // At this point it may be possible that no osthread was created for the
1.64 + // JavaThread due to lack of memory. We would have to throw an exception
1.65 + // in that case. However, since this must work and we do not allow
1.66 + // exceptions anyway, check and abort if this fails.
1.67 + if (thread == NULL || thread->osthread() == NULL) {
1.68 + vm_exit_during_initialization("java.lang.OutOfMemoryError",
1.69 + "unable to create new native thread");
1.70 + }
1.71 +
1.72 + java_lang_Thread::set_thread(thread_oop(), thread);
1.73 + java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
1.74 + java_lang_Thread::set_daemon(thread_oop());
1.75 + thread->set_threadObj(thread_oop());
1.76 +
1.77 + Threads::add(thread);
1.78 + Thread::start(thread);
1.79 +
1.80 + _instance = thread;
1.81 + }
1.82 +}
1.83 +
1.84 +void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {
1.85 + while (true) {
1.86 + bool sensors_changed = false;
1.87 + bool has_jvmti_events = false;
1.88 + JvmtiDeferredEvent jvmti_event;
1.89 + {
1.90 + // Need state transition ThreadBlockInVM so that this thread
1.91 + // will be handled by safepoint correctly when this thread is
1.92 + // notified at a safepoint.
1.93 +
1.94 + // This ThreadBlockInVM object is not also considered to be
1.95 + // suspend-equivalent because ServiceThread is not visible to
1.96 + // external suspension.
1.97 +
1.98 + ThreadBlockInVM tbivm(jt);
1.99 +
1.100 + MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);
1.101 + while (!(sensors_changed = LowMemoryDetector::has_pending_requests()) &&
1.102 + !(has_jvmti_events = JvmtiDeferredEventQueue::has_events())) {
1.103 + // wait until one of the sensors has pending requests, or there is a
1.104 + // pending JVMTI event to post
1.105 + Service_lock->wait(Mutex::_no_safepoint_check_flag);
1.106 + }
1.107 +
1.108 + if (has_jvmti_events) {
1.109 + jvmti_event = JvmtiDeferredEventQueue::dequeue();
1.110 + }
1.111 + }
1.112 +
1.113 + if (has_jvmti_events) {
1.114 + jvmti_event.post();
1.115 + }
1.116 +
1.117 + if (sensors_changed) {
1.118 + LowMemoryDetector::process_sensor_changes(jt);
1.119 + }
1.120 + }
1.121 +}
1.122 +
1.123 +bool ServiceThread::is_service_thread(Thread* thread) {
1.124 + return thread == _instance;
1.125 +}
