Quelle task.cpp Sprache: C

/*
* Copyright (c) 1997, 2021, 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 "memory/allocation.hpp"
#include "runtime/init.hpp"
#include "runtime/javaThread.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/nonJavaThread.hpp"
#include "runtime/task.hpp"
#include "runtime/timer.hpp"

int PeriodicTask::_num_tasks = 0;
PeriodicTask* PeriodicTask::_tasks[PeriodicTask::max_tasks];

void PeriodicTask::real_time_tick(int delay_time) {
  assert(Thread::current()->is_Watcher_thread(), "must be WatcherThread");

  // The WatcherThread does not participate in the safepoint protocol
  // for the PeriodicTask_lock because it is not a JavaThread.
  MutexLocker ml(PeriodicTask_lock, Mutex::_no_safepoint_check_flag);
  int orig_num_tasks = _num_tasks;

  for(int index = 0; index < _num_tasks; index++) {
    _tasks[index]->execute_if_pending(delay_time);
    if (_num_tasks < orig_num_tasks) { // task dis-enrolled itself
      index--;  // re-do current slot as it has changed
      orig_num_tasks = _num_tasks;
    }
  }
}

int PeriodicTask::time_to_wait() {
  assert(PeriodicTask_lock->owned_by_self(), "PeriodicTask_lock required");

  if (_num_tasks == 0) {
    return 0; // sleep until shutdown or a task is enrolled
  }

  int delay = _tasks[0]->time_to_next_interval();
  for (int index = 1; index < _num_tasks; index++) {
    delay = MIN2(delay, _tasks[index]->time_to_next_interval());
  }
  return delay;
}

PeriodicTask::PeriodicTask(size_t interval_time) :
  _counter(0), _interval((int) interval_time) {
  // Sanity check the interval time
  assert(_interval >= PeriodicTask::min_interval &&
         _interval %  PeriodicTask::interval_gran == 0,
              "improper PeriodicTask interval time");
}

PeriodicTask::~PeriodicTask() {
  // This PeriodicTask may have already been disenrolled by a call
  // to disenroll() before the PeriodicTask was deleted.
  disenroll();
}

// enroll the current PeriodicTask
void PeriodicTask::enroll() {
  // Follow normal safepoint aware lock enter protocol if the caller does
  // not already own the PeriodicTask_lock. Otherwise, we don't try to
  // enter it again because VM internal Mutexes do not support recursion.
  //
  MutexLocker ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock);

  if (_num_tasks == PeriodicTask::max_tasks) {
    fatal("Overflow in PeriodicTask table");
  } else {
    _tasks[_num_tasks++] = this;
  }

  WatcherThread* thread = WatcherThread::watcher_thread();
  if (thread != NULL) {
    thread->unpark();
  } else {
    WatcherThread::start();
  }
}

// disenroll the current PeriodicTask
void PeriodicTask::disenroll() {
  // Follow normal safepoint aware lock enter protocol if the caller does
  // not already own the PeriodicTask_lock. Otherwise, we don't try to
  // enter it again because VM internal Mutexes do not support recursion.
  //
  MutexLocker ml(PeriodicTask_lock->owned_by_self() ? NULL : PeriodicTask_lock);

  int index;
  for(index = 0; index < _num_tasks && _tasks[index] != this; index++)
    ;

  if (index == _num_tasks) {
    return;
  }

  _num_tasks--;

  for (; index < _num_tasks; index++) {
    _tasks[index] = _tasks[index+1];
  }
}

quality72%

¤ Dauer der Verarbeitung: 0.13 Sekunden (vorverarbeitet) ¤

Wurzel

Suchen

Beweissystem der NASA

Beweissystem Isabelle

NIST Cobol Testsuite

Cephes Mathematical Library

Wiener Entwicklungsmethode

Haftungshinweis

Die Informationen auf dieser Webseite wurden nach bestem Wissen sorgfältig zusammengestellt. Es wird jedoch weder Vollständigkeit, noch Richtigkeit, noch Qualität der bereit gestellten Informationen zugesichert.

Bemerkung:

Die farbliche Syntaxdarstellung ist noch experimentell.