1 /*
   2  * Copyright (c) 2018, 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 "precompiled.hpp"
  26 #include "gc/shared/cardTableRS.hpp"
  27 #include "gc/shared/gcSettings.hpp"
  28 #include "runtime/arguments.hpp"
  29 #include "runtime/os.hpp"
  30 #include "utilities/globalDefinitions.hpp"
  31 
  32 size_t compute_heap_alignment() {
  33   // The card marking array and the offset arrays for old generations are
  34   // committed in os pages as well. Make sure they are entirely full (to
  35   // avoid partial page problems), e.g. if 512 bytes heap corresponds to 1
  36   // byte entry and the os page size is 4096, the maximum heap size should
  37   // be 512*4096 = 2MB aligned.
  38 
  39   size_t alignment = CardTableRS::ct_max_alignment_constraint();
  40 
  41   if (UseLargePages) {
  42       // In presence of large pages we have to make sure that our
  43       // alignment is large page aware.
  44       alignment = lcm(os::large_page_size(), alignment);
  45   }
  46 
  47   return alignment;
  48 }
  49 
  50 void GCSettings::initialize() {
  51   _initial_heap_byte_size = InitialHeapSize;
  52   _max_heap_byte_size     = MaxHeapSize;
  53   _min_heap_byte_size     = Arguments::min_heap_size();
  54 }