jdk8-mips64-public/hotspot: src/share/vm/runtime/serviceThread.cpp@b5cb079ecaa4

     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  */

    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 #include "services/gcNotifier.hpp"

    33 ServiceThread* ServiceThread::_instance = NULL;

    35 void ServiceThread::initialize() {

    36   EXCEPTION_MARK;

    38   instanceKlassHandle klass (THREAD,  SystemDictionary::Thread_klass());

    39   instanceHandle thread_oop = klass->allocate_instance_handle(CHECK);

    41   const char* name = JDK_Version::is_gte_jdk17x_version() ?

    42       "Service Thread" : "Low Memory Detector";

    44   Handle string = java_lang_String::create_from_str(name, CHECK);

    46   // Initialize thread_oop to put it into the system threadGroup

    47   Handle thread_group (THREAD, Universe::system_thread_group());

    48   JavaValue result(T_VOID);

    49   JavaCalls::call_special(&result, thread_oop,

    50                           klass,

    51                           vmSymbols::object_initializer_name(),

    52                           vmSymbols::threadgroup_string_void_signature(),

    53                           thread_group,

    54                           string,

    55                           CHECK);

    57   {

    58     MutexLocker mu(Threads_lock);

    59     ServiceThread* thread =  new ServiceThread(&service_thread_entry);

    61     // At this point it may be possible that no osthread was created for the

    62     // JavaThread due to lack of memory. We would have to throw an exception

    63     // in that case. However, since this must work and we do not allow

    64     // exceptions anyway, check and abort if this fails.

    65     if (thread == NULL || thread->osthread() == NULL) {

    66       vm_exit_during_initialization("java.lang.OutOfMemoryError",

    67                                     "unable to create new native thread");

    68     }

    70     java_lang_Thread::set_thread(thread_oop(), thread);

    71     java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);

    72     java_lang_Thread::set_daemon(thread_oop());

    73     thread->set_threadObj(thread_oop());

    74     _instance = thread;

    76     Threads::add(thread);

    77     Thread::start(thread);

    78   }

    79 }

    81 void ServiceThread::service_thread_entry(JavaThread* jt, TRAPS) {

    82   while (true) {

    83     bool sensors_changed = false;

    84     bool has_jvmti_events = false;

    85     bool has_gc_notification_event = false;

    86     JvmtiDeferredEvent jvmti_event;

    87     {

    88       // Need state transition ThreadBlockInVM so that this thread

    89       // will be handled by safepoint correctly when this thread is

    90       // notified at a safepoint.

    92       // This ThreadBlockInVM object is not also considered to be

    93       // suspend-equivalent because ServiceThread is not visible to

    94       // external suspension.

    96       ThreadBlockInVM tbivm(jt);

    98       MutexLockerEx ml(Service_lock, Mutex::_no_safepoint_check_flag);

    99       while (!(sensors_changed = LowMemoryDetector::has_pending_requests()) &&

   100              !(has_jvmti_events = JvmtiDeferredEventQueue::has_events()) &&

   101               !(has_gc_notification_event = GCNotifier::has_event())) {

   102         // wait until one of the sensors has pending requests, or there is a

   103         // pending JVMTI event or JMX GC notification to post

   104         Service_lock->wait(Mutex::_no_safepoint_check_flag);

   105       }

   107       if (has_jvmti_events) {

   108         jvmti_event = JvmtiDeferredEventQueue::dequeue();

   109       }

   110     }

   112     if (has_jvmti_events) {

   113       jvmti_event.post();

   114     }

   116     if (sensors_changed) {

   117       LowMemoryDetector::process_sensor_changes(jt);

   118     }

   120     if(has_gc_notification_event) {

   121         GCNotifier::sendNotification(CHECK);

   122     }

   123   }

   124 }

   126 bool ServiceThread::is_service_thread(Thread* thread) {

   127   return thread == _instance;

   128 }

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