JDK14/Java14源码在线阅读

/*
 * Copyright (c) 2012, 2019, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "jni.h"
#include "classfile/javaClasses.hpp"
#include "classfile/symbolTable.hpp"
#include "classfile/systemDictionary.hpp"
#include "jfr/jfr.hpp"
#include "jfr/jni/jfrJavaSupport.hpp"
#include "jfr/recorder/jfrRecorder.hpp"
#include "jfr/recorder/checkpoint/jfrCheckpointManager.hpp"
#include "jfr/recorder/service/jfrRecorderThread.hpp"
#include "memory/resourceArea.hpp"
#include "memory/universe.hpp"
#include "runtime/handles.inline.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/thread.inline.hpp"
#include "utilities/preserveException.hpp"
#include "utilities/macros.hpp"

static Thread* start_thread(instanceHandle thread_oop, ThreadFunction proc, TRAPS) {
  assert(thread_oop.not_null(), "invariant");
  assert(proc != NULL, "invariant");

  bool allocation_failed = false;
  JavaThread* new_thread = NULL;
  {
    MutexLocker mu(Threads_lock);
    new_thread = new JavaThread(proc);
    // At this point it may be possible that no
    // osthread was created for the JavaThread due to lack of memory.
    if (new_thread == NULL || new_thread->osthread() == NULL) {
      delete new_thread;
      allocation_failed = true;
    } else {
      java_lang_Thread::set_thread(thread_oop(), new_thread);
      java_lang_Thread::set_priority(thread_oop(), NormPriority);
      java_lang_Thread::set_daemon(thread_oop());
      new_thread->set_threadObj(thread_oop());
      Threads::add(new_thread);
    }
  }
  if (allocation_failed) {
    JfrJavaSupport::throw_out_of_memory_error("Unable to create native recording thread for JFR", CHECK_NULL);
  }
  Thread::start(new_thread);
  return new_thread;
}

JfrPostBox* JfrRecorderThread::_post_box = NULL;

JfrPostBox& JfrRecorderThread::post_box() {
  return *_post_box;
}

// defined in JfrRecorderThreadLoop.cpp
void recorderthread_entry(JavaThread*, Thread*);

bool JfrRecorderThread::start(JfrCheckpointManager* cp_manager, JfrPostBox* post_box, TRAPS) {
  assert(cp_manager != NULL, "invariant");
  assert(post_box != NULL, "invariant");
  _post_box = post_box;

  static const char klass[] = "jdk/jfr/internal/JVMUpcalls";
  static const char method[] = "createRecorderThread";
  static const char signature[] = "(Ljava/lang/ThreadGroup;Ljava/lang/ClassLoader;)Ljava/lang/Thread;";

  JavaValue result(T_OBJECT);
  JfrJavaArguments create_thread_args(&result, klass, method, signature, CHECK_false);

  // arguments
  create_thread_args.push_oop(Universe::system_thread_group());
  create_thread_args.push_oop(SystemDictionary::java_system_loader());

  JfrJavaSupport::call_static(&create_thread_args, CHECK_false);
  instanceHandle h_thread_oop(THREAD, (instanceOop)result.get_jobject());
  assert(h_thread_oop.not_null(), "invariant");
  // attempt thread start
  Thread* const t = start_thread(h_thread_oop, recorderthread_entry,THREAD);
  if (!HAS_PENDING_EXCEPTION) {
    Jfr::exclude_thread(t);
    cp_manager->register_service_thread(t);
    return true;
  }
  assert(HAS_PENDING_EXCEPTION, "invariant");
  // Start failed, remove the thread from the system thread group
  JavaValue void_result(T_VOID);

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