1 /*
   2  * Copyright (c) 2001, 2013, 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_implementation/parallelScavenge/generationSizer.hpp"
  27 #include "memory/collectorPolicy.hpp"
  28 
  29 void GenerationSizer::trace_gen_sizes(const char* const str) {
  30   if (TracePageSizes) {
  31     tty->print_cr("%s:  " SIZE_FORMAT "," SIZE_FORMAT " "
  32                   SIZE_FORMAT "," SIZE_FORMAT " "
  33                   SIZE_FORMAT,
  34                   str,
  35                   _min_old_size / K, _max_old_size / K,
  36                   _min_young_size / K, _max_young_size / K,
  37                   _max_heap_byte_size / K);
  38   }
  39 }
  40 
  41 void GenerationSizer::initialize_alignments() {
  42   _space_alignment = _gen_alignment = default_gen_alignment();
  43   _heap_alignment = compute_heap_alignment();
  44 }
  45 
  46 void GenerationSizer::initialize_flags() {
  47   // Do basic sizing work
  48   GenCollectorPolicy::initialize_flags();
  49 
  50   // The survivor ratio's are calculated "raw", unlike the
  51   // default gc, which adds 2 to the ratio value. We need to
  52   // make sure the values are valid before using them.
  53   if (MinSurvivorRatio < 3) {
  54     FLAG_SET_ERGO(uintx, MinSurvivorRatio, 3);
  55   }
  56 
  57   if (InitialSurvivorRatio < 3) {
  58     FLAG_SET_ERGO(uintx, InitialSurvivorRatio, 3);
  59   }
  60 }
  61 
  62 void GenerationSizer::initialize_size_info() {
  63   trace_gen_sizes("ps heap raw");
  64   const size_t max_page_sz = os::page_size_for_region(_max_heap_byte_size, 8);
  65   const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old
  66   const size_t min_page_sz = os::page_size_for_region(_min_heap_byte_size, min_pages);
  67   const size_t page_sz = MIN2(max_page_sz, min_page_sz);
  68 
  69   // Can a page size be something else than a power of two?
  70   assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2");
  71   size_t new_alignment = round_to(page_sz, _gen_alignment);
  72   if (new_alignment != _gen_alignment) {
  73     _gen_alignment = new_alignment;
  74     _space_alignment = new_alignment;
  75     // Redo everything from the start
  76     initialize_flags();
  77   }
  78   GenCollectorPolicy::initialize_size_info();
  79 
  80   trace_gen_sizes("ps heap rnd");
  81 }