/*

 * Copyright (c) 2013, 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/g1CardCounts.hpp"

#include "gc_implementation/g1/g1CollectedHeap.inline.hpp"

#include "gc_implementation/g1/g1CollectorPolicy.hpp"

#include "gc_implementation/g1/g1GCPhaseTimes.hpp"

#include "memory/cardTableModRefBS.hpp"

#include "services/memTracker.hpp"

#include "utilities/copy.hpp"

void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {

  if (has_count_table()) {

    assert(from_card_num < to_card_num,

           err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,

                   from_card_num, to_card_num));

    assert(to_card_num <= _committed_max_card_num,

           err_msg("to card num out of range: "

                   "to: "SIZE_FORMAT ", "

                   "max: "SIZE_FORMAT,

                   to_card_num, _committed_max_card_num));

    to_card_num = MIN2(_committed_max_card_num, to_card_num);

    Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));

  }

}

G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):

  _g1h(g1h), _card_counts(NULL),

  _reserved_max_card_num(0), _committed_max_card_num(0),

  _committed_size(0) {}

void G1CardCounts::initialize() {

  assert(_g1h->max_capacity() > 0, "initialization order");

  assert(_g1h->capacity() == 0, "initialization order");

  if (G1ConcRSHotCardLimit > 0) {

    // The max value we can store in the counts table is

    // max_jubyte. Guarantee the value of the hot

    // threshold limit is no more than this.

    guarantee(G1ConcRSHotCardLimit <= max_jubyte, "sanity");

    ModRefBarrierSet* bs = _g1h->mr_bs();

    guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");

    _ct_bs = (CardTableModRefBS*)bs;

    _ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());

    // Allocate/Reserve the counts table

    size_t reserved_bytes = _g1h->max_capacity();

    _reserved_max_card_num = reserved_bytes >> CardTableModRefBS::card_shift;

    size_t reserved_size = _reserved_max_card_num * sizeof(jbyte);

    ReservedSpace rs(ReservedSpace::allocation_align_size_up(reserved_size));

    if (!rs.is_reserved()) {

      warning("Could not reserve enough space for the card counts table");

      guarantee(!has_reserved_count_table(), "should be NULL");

      return;

    }

    MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);

    _card_counts_storage.initialize(rs, 0);

    _card_counts = (jubyte*) _card_counts_storage.low();

  }

}

void G1CardCounts::resize(size_t heap_capacity) {

  // Expand the card counts table to handle a heap with the given capacity.

  if (!has_reserved_count_table()) {

    // Don't expand if we failed to reserve the card counts table.

    return;

  }

  assert(_committed_size ==

         ReservedSpace::allocation_align_size_up(_committed_size),

         err_msg("Unaligned? committed_size: " SIZE_FORMAT, _committed_size));

  // Verify that the committed space for the card counts matches our

  // committed max card num. Note for some allocation alignments, the

  // amount of space actually committed for the counts table will be able

  // to span more cards than the number spanned by the maximum heap.

  size_t prev_committed_size = _committed_size;

  size_t prev_committed_card_num = committed_to_card_num(prev_committed_size);

  assert(prev_committed_card_num == _committed_max_card_num,

         err_msg("Card mismatch: "

                 "prev: " SIZE_FORMAT ", "

                 "committed: "SIZE_FORMAT", "

                 "reserved: "SIZE_FORMAT,

                 prev_committed_card_num, _committed_max_card_num, _reserved_max_card_num));

  size_t new_size = (heap_capacity >> CardTableModRefBS::card_shift) * sizeof(jbyte);

  size_t new_committed_size = ReservedSpace::allocation_align_size_up(new_size);

  size_t new_committed_card_num = committed_to_card_num(new_committed_size);

  if (_committed_max_card_num < new_committed_card_num) {

    // we need to expand the backing store for the card counts

    size_t expand_size = new_committed_size - prev_committed_size;

    if (!_card_counts_storage.expand_by(expand_size)) {

      warning("Card counts table backing store commit failure");

      return;

    }

    assert(_card_counts_storage.committed_size() == new_committed_size,

           "expansion commit failure");

    _committed_size = new_committed_size;

    _committed_max_card_num = new_committed_card_num;

    clear_range(prev_committed_card_num, _committed_max_card_num);

  }

}

uint G1CardCounts::add_card_count(jbyte* card_ptr) {

  // Returns the number of times the card has been refined.

  // If we failed to reserve/commit the counts table, return 0.

  // If card_ptr is beyond the committed end of the counts table,

  // return 0.

  // Otherwise return the actual count.

  // Unless G1ConcRSHotCardLimit has been set appropriately,

  // returning 0 will result in the card being considered

  // cold and will be refined immediately.

  uint count = 0;

  if (has_count_table()) {

    size_t card_num = ptr_2_card_num(card_ptr);

    if (card_num < _committed_max_card_num) {

      count = (uint) _card_counts[card_num];

      if (count < G1ConcRSHotCardLimit) {

        _card_counts[card_num] =

          (jubyte)(MIN2((uintx)(_card_counts[card_num] + 1), G1ConcRSHotCardLimit));

      }

    }

  }

  return count;

}

bool G1CardCounts::is_hot(uint count) {

  return (count >= G1ConcRSHotCardLimit);

}

void G1CardCounts::clear_region(HeapRegion* hr) {

  assert(!hr->isHumongous(), "Should have been cleared");

  if (has_count_table()) {

    HeapWord* bottom = hr->bottom();

    // We use the last address in hr as hr could be the

    // last region in the heap. In which case trying to find

    // the card for hr->end() will be an OOB accesss to the

    // card table.

    HeapWord* last = hr->end() - 1;

    assert(_g1h->g1_committed().contains(last),

           err_msg("last not in committed: "

                   "last: " PTR_FORMAT ", "

                   "committed: [" PTR_FORMAT ", " PTR_FORMAT ")",

                   last,

                   _g1h->g1_committed().start(),

                   _g1h->g1_committed().end()));

    const jbyte* from_card_ptr = _ct_bs->byte_for_const(bottom);

    const jbyte* last_card_ptr = _ct_bs->byte_for_const(last);

#ifdef ASSERT

    HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);

    assert(start_addr == hr->bottom(), "alignment");

    HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);

    assert((last_addr + CardTableModRefBS::card_size_in_words) == hr->end(), "alignment");

#endif // ASSERT

    // Clear the counts for the (exclusive) card range.

    size_t from_card_num = ptr_2_card_num(from_card_ptr);

    size_t to_card_num = ptr_2_card_num(last_card_ptr) + 1;

    clear_range(from_card_num, to_card_num);

  }

}

void G1CardCounts::clear_all() {

  assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");

  clear_range((size_t)0, _committed_max_card_num);

}

G1CardCounts::~G1CardCounts() {

  if (has_reserved_count_table()) {

    _card_counts_storage.release();

  }

}