view src/share/vm/runtime/jniPeriodicChecker.cpp @ 3979:4dfb2df418f2

6484982: G1: process references during evacuation pauses Summary: G1 now uses two reference processors - one is used by concurrent marking and the other is used by STW GCs (both full and incremental evacuation pauses). In an evacuation pause, the reference processor is embedded into the closures used to scan objects. Doing so causes causes reference objects to be 'discovered' by the reference processor. At the end of the evacuation pause, these discovered reference objects are processed - preserving (and copying) referent objects (and their reachable graphs) as appropriate. Reviewed-by: ysr, jwilhelm, brutisso, stefank, tonyp
author johnc
date Thu, 22 Sep 2011 10:57:37 -0700
parents f95d63e2154a
children
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/*
 * Copyright (c) 2007, 2010, 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.inline.hpp"
#include "runtime/jniPeriodicChecker.hpp"
#include "runtime/task.hpp"


// --------------------------------------------------------
// Class to aid in periodic checking under CheckJNICalls
class JniPeriodicCheckerTask : public PeriodicTask {
  public:
     JniPeriodicCheckerTask(int interval_time) : PeriodicTask(interval_time) {}
     void task() { os::run_periodic_checks(); }
     static void engage();
     static void disengage();
};


//----------------------------------------------------------
// Implementation of JniPeriodicChecker

JniPeriodicCheckerTask*              JniPeriodicChecker::_task   = NULL;

/*
 * The engage() method is called at initialization time via
 * Thread::create_vm() to initialize the JniPeriodicChecker and
 * register it with the WatcherThread as a periodic task.
 */
void JniPeriodicChecker::engage() {
  if (CheckJNICalls && !is_active()) {
    // start up the periodic task
    _task = new JniPeriodicCheckerTask(10);
    _task->enroll();
  }
}


/*
 * the disengage() method is responsible for deactivating the periodic
 * task. This  method is called from before_exit() in java.cpp and is only called
 * after the WatcherThread has been stopped.
 */
void JniPeriodicChecker::disengage() {
  if (CheckJNICalls && is_active()) {
    // remove JniPeriodicChecker
    _task->disenroll();
    delete _task;
    _task = NULL;
  }
}

void jniPeriodicChecker_exit() {
  if (!CheckJNICalls) return;
}