view src/share/vm/gc_implementation/g1/dirtyCardQueue.cpp @ 2034:7e37af9d69ef

7011379: G1: overly long concurrent marking cycles Summary: This changeset introduces filtering of SATB buffers at the point when they are about to be enqueued. If this filtering clears enough entries on each buffer, the buffer can then be re-used and not enqueued. This cuts down the number of SATB buffers that need to be processed by the concurrent marking threads. Reviewed-by: johnc, ysr
author tonyp
date Wed, 19 Jan 2011 09:35:17 -0500
parents 2d160770d2e5
children f08d439fab8c
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/*
 * Copyright (c) 2001, 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 "gc_implementation/g1/dirtyCardQueue.hpp"
#include "gc_implementation/g1/heapRegionRemSet.hpp"
#include "runtime/atomic.hpp"
#include "runtime/mutexLocker.hpp"
#include "runtime/safepoint.hpp"
#include "runtime/thread.hpp"
#include "utilities/workgroup.hpp"
#ifdef TARGET_OS_FAMILY_linux
# include "thread_linux.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_solaris
# include "thread_solaris.inline.hpp"
#endif
#ifdef TARGET_OS_FAMILY_windows
# include "thread_windows.inline.hpp"
#endif

bool DirtyCardQueue::apply_closure(CardTableEntryClosure* cl,
                                   bool consume,
                                   size_t worker_i) {
  bool res = true;
  if (_buf != NULL) {
    res = apply_closure_to_buffer(cl, _buf, _index, _sz,
                                  consume,
                                  (int) worker_i);
    if (res && consume) _index = _sz;
  }
  return res;
}

bool DirtyCardQueue::apply_closure_to_buffer(CardTableEntryClosure* cl,
                                             void** buf,
                                             size_t index, size_t sz,
                                             bool consume,
                                             int worker_i) {
  if (cl == NULL) return true;
  for (size_t i = index; i < sz; i += oopSize) {
    int ind = byte_index_to_index((int)i);
    jbyte* card_ptr = (jbyte*)buf[ind];
    if (card_ptr != NULL) {
      // Set the entry to null, so we don't do it again (via the test
      // above) if we reconsider this buffer.
      if (consume) buf[ind] = NULL;
      if (!cl->do_card_ptr(card_ptr, worker_i)) return false;
    }
  }
  return true;
}

#ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
#pragma warning( disable:4355 ) // 'this' : used in base member initializer list
#endif // _MSC_VER

DirtyCardQueueSet::DirtyCardQueueSet(bool notify_when_complete) :
  PtrQueueSet(notify_when_complete),
  _closure(NULL),
  _shared_dirty_card_queue(this, true /*perm*/),
  _free_ids(NULL),
  _processed_buffers_mut(0), _processed_buffers_rs_thread(0)
{
  _all_active = true;
}

// Determines how many mutator threads can process the buffers in parallel.
size_t DirtyCardQueueSet::num_par_ids() {
  return os::processor_count();
}

void DirtyCardQueueSet::initialize(Monitor* cbl_mon, Mutex* fl_lock,
                                   int process_completed_threshold,
                                   int max_completed_queue,
                                   Mutex* lock, PtrQueueSet* fl_owner) {
  PtrQueueSet::initialize(cbl_mon, fl_lock, process_completed_threshold,
                          max_completed_queue, fl_owner);
  set_buffer_size(G1UpdateBufferSize);
  _shared_dirty_card_queue.set_lock(lock);
  _free_ids = new FreeIdSet((int) num_par_ids(), _cbl_mon);
}

void DirtyCardQueueSet::handle_zero_index_for_thread(JavaThread* t) {
  t->dirty_card_queue().handle_zero_index();
}

void DirtyCardQueueSet::set_closure(CardTableEntryClosure* closure) {
  _closure = closure;
}

void DirtyCardQueueSet::iterate_closure_all_threads(bool consume,
                                                    size_t worker_i) {
  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
  for(JavaThread* t = Threads::first(); t; t = t->next()) {
    bool b = t->dirty_card_queue().apply_closure(_closure, consume);
    guarantee(b, "Should not be interrupted.");
  }
  bool b = shared_dirty_card_queue()->apply_closure(_closure,
                                                    consume,
                                                    worker_i);
  guarantee(b, "Should not be interrupted.");
}

bool DirtyCardQueueSet::mut_process_buffer(void** buf) {

  // Used to determine if we had already claimed a par_id
  // before entering this method.
  bool already_claimed = false;

  // We grab the current JavaThread.
  JavaThread* thread = JavaThread::current();

  // We get the the number of any par_id that this thread
  // might have already claimed.
  int worker_i = thread->get_claimed_par_id();

  // If worker_i is not -1 then the thread has already claimed
  // a par_id. We make note of it using the already_claimed value
  if (worker_i != -1) {
    already_claimed = true;
  } else {

    // Otherwise we need to claim a par id
    worker_i = _free_ids->claim_par_id();

    // And store the par_id value in the thread
    thread->set_claimed_par_id(worker_i);
  }

  bool b = false;
  if (worker_i != -1) {
    b = DirtyCardQueue::apply_closure_to_buffer(_closure, buf, 0,
                                                _sz, true, worker_i);
    if (b) Atomic::inc(&_processed_buffers_mut);

    // If we had not claimed an id before entering the method
    // then we must release the id.
    if (!already_claimed) {

      // we release the id
      _free_ids->release_par_id(worker_i);

      // and set the claimed_id in the thread to -1
      thread->set_claimed_par_id(-1);
    }
  }
  return b;
}


BufferNode*
DirtyCardQueueSet::get_completed_buffer(int stop_at) {
  BufferNode* nd = NULL;
  MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);

  if ((int)_n_completed_buffers <= stop_at) {
    _process_completed = false;
    return NULL;
  }

  if (_completed_buffers_head != NULL) {
    nd = _completed_buffers_head;
    _completed_buffers_head = nd->next();
    if (_completed_buffers_head == NULL)
      _completed_buffers_tail = NULL;
    _n_completed_buffers--;
    assert(_n_completed_buffers >= 0, "Invariant");
  }
  debug_only(assert_completed_buffer_list_len_correct_locked());
  return nd;
}

bool DirtyCardQueueSet::
apply_closure_to_completed_buffer_helper(CardTableEntryClosure* cl,
                                         int worker_i,
                                         BufferNode* nd) {
  if (nd != NULL) {
    void **buf = BufferNode::make_buffer_from_node(nd);
    size_t index = nd->index();
    bool b =
      DirtyCardQueue::apply_closure_to_buffer(cl, buf,
                                              index, _sz,
                                              true, worker_i);
    if (b) {
      deallocate_buffer(buf);
      return true;  // In normal case, go on to next buffer.
    } else {
      enqueue_complete_buffer(buf, index);
      return false;
    }
  } else {
    return false;
  }
}

bool DirtyCardQueueSet::apply_closure_to_completed_buffer(CardTableEntryClosure* cl,
                                                          int worker_i,
                                                          int stop_at,
                                                          bool during_pause) {
  assert(!during_pause || stop_at == 0, "Should not leave any completed buffers during a pause");
  BufferNode* nd = get_completed_buffer(stop_at);
  bool res = apply_closure_to_completed_buffer_helper(cl, worker_i, nd);
  if (res) Atomic::inc(&_processed_buffers_rs_thread);
  return res;
}

bool DirtyCardQueueSet::apply_closure_to_completed_buffer(int worker_i,
                                                          int stop_at,
                                                          bool during_pause) {
  return apply_closure_to_completed_buffer(_closure, worker_i,
                                           stop_at, during_pause);
}

void DirtyCardQueueSet::apply_closure_to_all_completed_buffers() {
  BufferNode* nd = _completed_buffers_head;
  while (nd != NULL) {
    bool b =
      DirtyCardQueue::apply_closure_to_buffer(_closure,
                                              BufferNode::make_buffer_from_node(nd),
                                              0, _sz, false);
    guarantee(b, "Should not stop early.");
    nd = nd->next();
  }
}

// Deallocates any completed log buffers
void DirtyCardQueueSet::clear() {
  BufferNode* buffers_to_delete = NULL;
  {
    MutexLockerEx x(_cbl_mon, Mutex::_no_safepoint_check_flag);
    while (_completed_buffers_head != NULL) {
      BufferNode* nd = _completed_buffers_head;
      _completed_buffers_head = nd->next();
      nd->set_next(buffers_to_delete);
      buffers_to_delete = nd;
    }
    _n_completed_buffers = 0;
    _completed_buffers_tail = NULL;
    debug_only(assert_completed_buffer_list_len_correct_locked());
  }
  while (buffers_to_delete != NULL) {
    BufferNode* nd = buffers_to_delete;
    buffers_to_delete = nd->next();
    deallocate_buffer(BufferNode::make_buffer_from_node(nd));
  }

}

void DirtyCardQueueSet::abandon_logs() {
  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
  clear();
  // Since abandon is done only at safepoints, we can safely manipulate
  // these queues.
  for (JavaThread* t = Threads::first(); t; t = t->next()) {
    t->dirty_card_queue().reset();
  }
  shared_dirty_card_queue()->reset();
}


void DirtyCardQueueSet::concatenate_logs() {
  // Iterate over all the threads, if we find a partial log add it to
  // the global list of logs.  Temporarily turn off the limit on the number
  // of outstanding buffers.
  int save_max_completed_queue = _max_completed_queue;
  _max_completed_queue = max_jint;
  assert(SafepointSynchronize::is_at_safepoint(), "Must be at safepoint.");
  for (JavaThread* t = Threads::first(); t; t = t->next()) {
    DirtyCardQueue& dcq = t->dirty_card_queue();
    if (dcq.size() != 0) {
      void **buf = t->dirty_card_queue().get_buf();
      // We must NULL out the unused entries, then enqueue.
      for (size_t i = 0; i < t->dirty_card_queue().get_index(); i += oopSize) {
        buf[PtrQueue::byte_index_to_index((int)i)] = NULL;
      }
      enqueue_complete_buffer(dcq.get_buf(), dcq.get_index());
      dcq.reinitialize();
    }
  }
  if (_shared_dirty_card_queue.size() != 0) {
    enqueue_complete_buffer(_shared_dirty_card_queue.get_buf(),
                            _shared_dirty_card_queue.get_index());
    _shared_dirty_card_queue.reinitialize();
  }
  // Restore the completed buffer queue limit.
  _max_completed_queue = save_max_completed_queue;
}