/*

 * Copyright (c) 2001, 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/parallelScavenge/objectStartArray.hpp"

#include "memory/allocation.inline.hpp"

#include "memory/cardTableModRefBS.hpp"

#include "oops/oop.inline.hpp"

#include "runtime/java.hpp"

#include "services/memTracker.hpp"

void ObjectStartArray::initialize(MemRegion reserved_region) {

  // We're based on the assumption that we use the same

  // size blocks as the card table.

  assert((int)block_size == (int)CardTableModRefBS::card_size, "Sanity");

  assert((int)block_size <= 512, "block_size must be less than or equal to 512");

  // Calculate how much space must be reserved

  _reserved_region = reserved_region;

  size_t bytes_to_reserve = reserved_region.word_size() / block_size_in_words;

  assert(bytes_to_reserve > 0, "Sanity");

  bytes_to_reserve =

    align_size_up(bytes_to_reserve, os::vm_allocation_granularity());

  // Do not use large-pages for the backing store. The one large page region

  // will be used for the heap proper.

  ReservedSpace backing_store(bytes_to_reserve);

  if (!backing_store.is_reserved()) {

    vm_exit_during_initialization("Could not reserve space for ObjectStartArray");

  }

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

  // We do not commit any memory initially

  if (!_virtual_space.initialize(backing_store, 0)) {

    vm_exit_during_initialization("Could not commit space for ObjectStartArray");

  }

  _raw_base = (jbyte*)_virtual_space.low_boundary();

  if (_raw_base == NULL) {

    vm_exit_during_initialization("Could not get raw_base address");

  }

  MemTracker::record_virtual_memory_type((address)_raw_base, mtGC);

  _offset_base = _raw_base - (size_t(reserved_region.start()) >> block_shift);

  _covered_region.set_start(reserved_region.start());

  _covered_region.set_word_size(0);

  _blocks_region.set_start((HeapWord*)_raw_base);

  _blocks_region.set_word_size(0);

}

void ObjectStartArray::set_covered_region(MemRegion mr) {

  assert(_reserved_region.contains(mr), "MemRegion outside of reserved space");

  assert(_reserved_region.start() == mr.start(), "Attempt to move covered region");

  HeapWord* low_bound  = mr.start();

  HeapWord* high_bound = mr.end();

  assert((uintptr_t(low_bound)  & (block_size - 1))  == 0, "heap must start at block boundary");

  assert((uintptr_t(high_bound) & (block_size - 1))  == 0, "heap must end at block boundary");

  size_t requested_blocks_size_in_bytes = mr.word_size() / block_size_in_words;

  // Only commit memory in page sized chunks

  requested_blocks_size_in_bytes =

    align_size_up(requested_blocks_size_in_bytes, os::vm_page_size());

  _covered_region = mr;

  size_t current_blocks_size_in_bytes = _blocks_region.byte_size();

  if (requested_blocks_size_in_bytes > current_blocks_size_in_bytes) {

    // Expand

    size_t expand_by = requested_blocks_size_in_bytes - current_blocks_size_in_bytes;

    if (!_virtual_space.expand_by(expand_by)) {

      vm_exit_out_of_memory(expand_by, OOM_MMAP_ERROR, "object start array expansion");

    }

    // Clear *only* the newly allocated region

    memset(_blocks_region.end(), clean_block, expand_by);

  }

  if (requested_blocks_size_in_bytes < current_blocks_size_in_bytes) {

    // Shrink

    size_t shrink_by = current_blocks_size_in_bytes - requested_blocks_size_in_bytes;

    _virtual_space.shrink_by(shrink_by);

  }

  _blocks_region.set_word_size(requested_blocks_size_in_bytes / sizeof(HeapWord));

  assert(requested_blocks_size_in_bytes % sizeof(HeapWord) == 0, "Block table not expanded in word sized increment");

  assert(requested_blocks_size_in_bytes == _blocks_region.byte_size(), "Sanity");

  assert(block_for_addr(low_bound) == &_raw_base[0], "Checking start of map");

  assert(block_for_addr(high_bound-1) <= &_raw_base[_blocks_region.byte_size()-1], "Checking end of map");

}

void ObjectStartArray::reset() {

  memset(_blocks_region.start(), clean_block, _blocks_region.byte_size());

}

bool ObjectStartArray::object_starts_in_range(HeapWord* start_addr,

                                              HeapWord* end_addr) const {

  if (start_addr > end_addr) {

    return false;

  }

  jbyte* start_block = block_for_addr(start_addr);

  jbyte* end_block = block_for_addr(end_addr);

  for (jbyte* block = start_block; block <= end_block; block++) {

    if (*block != clean_block) {

      return true;

    }

  }

  return false;

}