1 /*
   2  * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved.
   3  * Copyright (c) 2020 SAP SE. All rights reserved.
   4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   5  *
   6  * This code is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 only, as
   8  * published by the Free Software Foundation.
   9  *
  10  * This code is distributed in the hope that it will be useful, but WITHOUT
  11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  13  * version 2 for more details (a copy is included in the LICENSE file that
  14  * accompanied this code).
  15  *
  16  * You should have received a copy of the GNU General Public License version
  17  * 2 along with this work; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  19  *
  20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  21  * or visit www.oracle.com if you need additional information or have any
  22  * questions.
  23  *
  24  */
  25 
  26 #include "precompiled.hpp"
  27 #include "memory/metaspace/freeBlocks.hpp"
  28 #include "utilities/globalDefinitions.hpp"
  29 #include "utilities/debug.hpp"
  30 
  31 namespace metaspace {
  32 
  33 void FreeBlocks::add_block(MetaWord* p, size_t word_size) {
  34   assert(word_size >= minimal_word_size, "sanity (" SIZE_FORMAT ")", word_size);
  35   if (word_size >= _small_blocks.maximal_word_size) {
  36     _tree.add_block(p, word_size);
  37   } else {
  38     _small_blocks.add_block(p, word_size);
  39   }
  40 }
  41 
  42 MetaWord* FreeBlocks::get_block(size_t requested_word_size) {
  43   assert(requested_word_size >= minimal_word_size,
  44       "requested_word_size too small (" SIZE_FORMAT ")", requested_word_size);
  45   size_t real_size = 0;
  46   MetaWord* p = NULL;
  47   if (requested_word_size >= _small_blocks.maximal_word_size) {
  48     p = _tree.get_block(requested_word_size, &real_size);
  49   } else {
  50     p = _small_blocks.get_block(requested_word_size, &real_size);
  51   }
  52   if (p != NULL) {
  53     // Blocks which are larger than a certain threshold are split and
  54     // the remainder is handed back to the manager.
  55     const size_t waste = real_size - requested_word_size;
  56     if (waste > MAX2(minimal_word_size, splinter_threshold)) {
  57       add_block(p + requested_word_size, waste);
  58     }
  59   }
  60   return p;
  61 }
  62 
  63 } // namespace metaspace
  64