1 /*
   2  * Copyright (c) 2003, 2005, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
   8  *
   9  * This code is distributed in the hope that it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  12  * version 2 for more details (a copy is included in the LICENSE file that
  13  * accompanied this code).
  14  *
  15  * You should have received a copy of the GNU General Public License version
  16  * 2 along with this work; if not, write to the Free Software Foundation,
  17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  18  *
  19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  20  * or visit www.oracle.com if you need additional information or have any
  21  * questions.
  22  *
  23  */
  24 
  25 # include "incls/_precompiled.incl"
  26 # include "incls/_adjoiningVirtualSpaces.cpp.incl"
  27 
  28 AdjoiningVirtualSpaces::AdjoiningVirtualSpaces(ReservedSpace rs,
  29                                                size_t min_low_byte_size,
  30                                                size_t min_high_byte_size,
  31                                                size_t alignment) :
  32   _reserved_space(rs), _min_low_byte_size(min_low_byte_size),
  33   _min_high_byte_size(min_high_byte_size), _low(0), _high(0),
  34   _alignment(alignment) {}
  35 
  36 // The maximum byte sizes are for the initial layout of the
  37 // virtual spaces and are not the limit on the maximum bytes sizes.
  38 void AdjoiningVirtualSpaces::initialize(size_t max_low_byte_size,
  39                                         size_t init_low_byte_size,
  40                                         size_t init_high_byte_size) {
  41 
  42   // The reserved spaces for the two parts of the virtual space.
  43   ReservedSpace old_rs   = _reserved_space.first_part(max_low_byte_size);
  44   ReservedSpace young_rs = _reserved_space.last_part(max_low_byte_size);
  45 
  46   _low = new PSVirtualSpace(old_rs, alignment());
  47   if (!_low->expand_by(init_low_byte_size)) {
  48     vm_exit_during_initialization("Could not reserve enough space for "
  49                                   "object heap");
  50   }
  51 
  52   _high = new PSVirtualSpaceHighToLow(young_rs, alignment());
  53   if (!_high->expand_by(init_high_byte_size)) {
  54     vm_exit_during_initialization("Could not reserve enough space for "
  55                                   "object heap");
  56   }
  57 }
  58 
  59 bool AdjoiningVirtualSpaces::adjust_boundary_up(size_t change_in_bytes) {
  60   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
  61   size_t actual_change = low()->expand_into(high(), change_in_bytes);
  62   return actual_change != 0;
  63 }
  64 
  65 bool AdjoiningVirtualSpaces::adjust_boundary_down(size_t change_in_bytes) {
  66   assert(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary, "runtime check");
  67   size_t actual_change = high()->expand_into(low(), change_in_bytes);
  68   return actual_change != 0;
  69 }