/*

 * Copyright 2001-2007 Sun Microsystems, Inc.  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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,

 * CA 95054 USA or visit www.sun.com if you need additional information or

 * have any questions.

 *

 */

#include "incls/_precompiled.incl"

#include "incls/_concurrentG1RefineThread.cpp.incl"

// ======= Concurrent Mark Thread ========

// The CM thread is created when the G1 garbage collector is used

ConcurrentG1RefineThread::

ConcurrentG1RefineThread(ConcurrentG1Refine* cg1r) :

  ConcurrentGCThread(),

  _cg1r(cg1r),

  _started(false),

  _in_progress(false),

  _do_traversal(false),

  _vtime_accum(0.0),

  _co_tracker(G1CRGroup),

  _interval_ms(5.0)

{

  create_and_start();

}

const long timeout = 200; // ms.

void ConcurrentG1RefineThread::traversalBasedRefinement() {

  _cg1r->wait_for_ConcurrentG1Refine_enabled();

  MutexLocker x(G1ConcRefine_mon);

  while (_cg1r->enabled()) {

    MutexUnlocker ux(G1ConcRefine_mon);

    ResourceMark rm;

    HandleMark   hm;

    if (TraceG1Refine) gclog_or_tty->print_cr("G1-Refine starting pass");

    _sts.join();

    bool no_sleep = _cg1r->refine();

    _sts.leave();

    if (!no_sleep) {

      MutexLockerEx x(CGC_lock, Mutex::_no_safepoint_check_flag);

      // We do this only for the timeout; we don't expect this to be signalled.

      CGC_lock->wait(Mutex::_no_safepoint_check_flag, timeout);

    }

  }

}

void ConcurrentG1RefineThread::queueBasedRefinement() {

  DirtyCardQueueSet& dcqs = JavaThread::dirty_card_queue_set();

  // Wait for completed log buffers to exist.

  {

    MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);

    while (!_do_traversal && !dcqs.process_completed_buffers() &&

           !_should_terminate) {

      DirtyCardQ_CBL_mon->wait(Mutex::_no_safepoint_check_flag);

    }

  }

  if (_should_terminate) {

    return;

  }

  // Now we take them off (this doesn't hold locks while it applies

  // closures.)  (If we did a full collection, then we'll do a full

  // traversal.

  _sts.join();

  if (_do_traversal) {

    (void)_cg1r->refine();

    switch (_cg1r->get_last_pya()) {

    case PYA_cancel: case PYA_continue:

      // Continue was caught and handled inside "refine".  If it's still

      // "continue" when we get here, we're done.

      _do_traversal = false;

      break;

    case PYA_restart:

      assert(_do_traversal, "Because of Full GC.");

      break;

    }

  } else {

    int n_logs = 0;

    int lower_limit = 0;

    double start_vtime_sec; // only used when G1SmoothConcRefine is on

    int prev_buffer_num; // only used when G1SmoothConcRefine is on

    if (G1SmoothConcRefine) {

      lower_limit = 0;

      start_vtime_sec = os::elapsedVTime();

      prev_buffer_num = (int) dcqs.completed_buffers_num();

    } else {

      lower_limit = DCQBarrierProcessCompletedThreshold / 4; // For now.

    }

    while (dcqs.apply_closure_to_completed_buffer(0, lower_limit)) {

      double end_vtime_sec;

      double elapsed_vtime_sec;

      int elapsed_vtime_ms;

      int curr_buffer_num;

      if (G1SmoothConcRefine) {

        end_vtime_sec = os::elapsedVTime();

        elapsed_vtime_sec = end_vtime_sec - start_vtime_sec;

        elapsed_vtime_ms = (int) (elapsed_vtime_sec * 1000.0);

        curr_buffer_num = (int) dcqs.completed_buffers_num();

        if (curr_buffer_num > prev_buffer_num ||

            curr_buffer_num > DCQBarrierProcessCompletedThreshold) {

          decreaseInterval(elapsed_vtime_ms);

        } else if (curr_buffer_num < prev_buffer_num) {

          increaseInterval(elapsed_vtime_ms);

        }

      }

      sample_young_list_rs_lengths();

      _co_tracker.update(false);

      if (G1SmoothConcRefine) {

        start_vtime_sec = os::elapsedVTime();

        prev_buffer_num = curr_buffer_num;

        _sts.leave();

        os::sleep(Thread::current(), (jlong) _interval_ms, false);

        _sts.join();

      }

      n_logs++;

    }

    // Make sure we harvest the PYA, if any.

    (void)_cg1r->get_pya();

  }

  _sts.leave();

}

void ConcurrentG1RefineThread::sample_young_list_rs_lengths() {

  G1CollectedHeap* g1h = G1CollectedHeap::heap();

  G1CollectorPolicy* g1p = g1h->g1_policy();

  if (g1p->adaptive_young_list_length()) {

    int regions_visited = 0;

    g1h->young_list_rs_length_sampling_init();

    while (g1h->young_list_rs_length_sampling_more()) {

      g1h->young_list_rs_length_sampling_next();

      ++regions_visited;

      // we try to yield every time we visit 10 regions

      if (regions_visited == 10) {

        if (_sts.should_yield()) {

          _sts.yield("G1 refine");

          // we just abandon the iteration

          break;

        }

        regions_visited = 0;

      }

    }

    g1p->check_prediction_validity();

  }

}

void ConcurrentG1RefineThread::run() {

  initialize_in_thread();

  _vtime_start = os::elapsedVTime();

  wait_for_universe_init();

  _co_tracker.enable();

  _co_tracker.start();

  while (!_should_terminate) {

    // wait until started is set.

    if (G1RSBarrierUseQueue) {

      queueBasedRefinement();

    } else {

      traversalBasedRefinement();

    }

    _sts.join();

    _co_tracker.update();

    _sts.leave();

    if (os::supports_vtime()) {

      _vtime_accum = (os::elapsedVTime() - _vtime_start);

    } else {

      _vtime_accum = 0.0;

    }

  }

  _sts.join();

  _co_tracker.update(true);

  _sts.leave();

  assert(_should_terminate, "just checking");

  terminate();

}

void ConcurrentG1RefineThread::yield() {

  if (TraceG1Refine) gclog_or_tty->print_cr("G1-Refine-yield");

  _sts.yield("G1 refine");

  if (TraceG1Refine) gclog_or_tty->print_cr("G1-Refine-yield-end");

}

void ConcurrentG1RefineThread::stop() {

  // it is ok to take late safepoints here, if needed

  {

    MutexLockerEx mu(Terminator_lock);

    _should_terminate = true;

  }

  {

    MutexLockerEx x(DirtyCardQ_CBL_mon, Mutex::_no_safepoint_check_flag);

    DirtyCardQ_CBL_mon->notify_all();

  }

  {

    MutexLockerEx mu(Terminator_lock);

    while (!_has_terminated) {

      Terminator_lock->wait();

    }

  }

  if (TraceG1Refine) gclog_or_tty->print_cr("G1-Refine-stop");

}

void ConcurrentG1RefineThread::print() {

  gclog_or_tty->print("\"Concurrent G1 Refinement Thread\" ");

  Thread::print();

  gclog_or_tty->cr();

}

void ConcurrentG1RefineThread::set_do_traversal(bool b) {

  _do_traversal = b;

}