/*
 * Copyright (c) 2001, 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 "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1ConcurrentHeapResizeThread.hpp"
#include "gc/g1/g1Policy.hpp"

G1ConcurrentHeapResizeThread::G1ConcurrentHeapResizeThread(G1ConcurrentHeapResize* heap_resize) :
  ConcurrentGCThread(),
  _concurrent_heap_resize(heap_resize),
  _state(Idle),
  _start_monitor(NULL),
  _done_monitor(NULL) {

  _start_monitor = new Monitor(Mutex::nonleaf, "Concurrent resize start monitor", true,
                           Monitor::_safepoint_check_never);
  _done_monitor = new Monitor(Mutex::nonleaf, "Concurrent resize done monitor", true,
                           Monitor::_safepoint_check_never);

  set_name("G1 concurrent heap resizer");
  create_and_start();
}

void G1ConcurrentHeapResizeThread::run_service() {

  G1CollectedHeap* g1h = G1CollectedHeap::heap();
  G1Policy* policy = g1h->policy();

  while (!should_terminate()) {
    // wait until working is set.
    sleep_before_next_cycle();
    if (should_terminate()) {
      break;
    }
    concurrent_heap_resize()->do_work();
    concurrent_heap_resize()->notify_work_done();
  }
}

void G1ConcurrentHeapResizeThread::stop_service() {
  MutexLocker ml(_start_monitor, Mutex::_no_safepoint_check_flag);
  _start_monitor->notify_all();
}

void G1ConcurrentHeapResizeThread::sleep_before_next_cycle() {
  assert(!working(), "should have been cleared");

  MonitorLocker ml(_start_monitor, Mutex::_no_safepoint_check_flag);
  while (!working() && !should_terminate()) {
    ml.wait();
  }
}