Java example source code file (adjoiningVirtualSpaces.cpp)

This example Java source code file (adjoiningVirtualSpaces.cpp) is included in the alvinalexander.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Learn more about this Java project at its project page.

Java - Java tags/keywords

adjoiningvirtualspaces::initialize, adjoiningvirtualspaces\:\:adjoiningvirtualspaces, adjoiningvirtualspaces\:\:adjust_boundary_down, adjoiningvirtualspaces\:\:adjust_boundary_up, could, psvirtualspacehightolow, reservedspace, useadaptivegcboundary

The adjoiningVirtualSpaces.cpp Java example source code

/*
 * Copyright (c) 2003, 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/parallelScavenge/adjoiningVirtualSpaces.hpp"
#include "memory/allocation.inline.hpp"
#include "runtime/java.hpp"

AdjoiningVirtualSpaces::AdjoiningVirtualSpaces(ReservedSpace rs,
                                               size_t min_low_byte_size,
                                               size_t min_high_byte_size,
                                               size_t alignment) :
  _reserved_space(rs), _min_low_byte_size(min_low_byte_size),
  _min_high_byte_size(min_high_byte_size), _low(0), _high(0),
  _alignment(alignment) {}

// The maximum byte sizes are for the initial layout of the
// virtual spaces and are not the limit on the maximum bytes sizes.
void AdjoiningVirtualSpaces::initialize(size_t max_low_byte_size,
                                        size_t init_low_byte_size,
                                        size_t init_high_byte_size) {

  // The reserved spaces for the two parts of the virtual space.
  ReservedSpace old_rs   = _reserved_space.first_part(max_low_byte_size);
  ReservedSpace young_rs = _reserved_space.last_part(max_low_byte_size);

  _low = new PSVirtualSpace(old_rs, alignment());
  if (!_low->expand_by(init_low_byte_size)) {
    vm_exit_during_initialization("Could not reserve enough space for "
                                  "object heap");
  }

  _high = new PSVirtualSpaceHighToLow(young_rs, alignment());
  if (!_high->expand_by(init_high_byte_size)) {
    vm_exit_during_initialization("Could not reserve enough space for "
                                  "object heap");
  }
}

bool AdjoiningVirtualSpaces::adjust_boundary_up(size_t change_in_bytes) {
  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
  size_t actual_change = low()->expand_into(high(), change_in_bytes);
  return actual_change != 0;
}

bool AdjoiningVirtualSpaces::adjust_boundary_down(size_t change_in_bytes) {
  assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
  size_t actual_change = high()->expand_into(low(), change_in_bytes);
  return actual_change != 0;
}