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/debug.hpp"
29 #include "utilities/globalDefinitions.hpp"
30 
31 namespace metaspace {
32 
33 void FreeBlocks::add_block(MetaWord* p, size_t word_size) {
34   assert(word_size >= MinWordSize, "sanity (" SIZE_FORMAT ")", word_size);
35   if (word_size > MaxSmallBlocksWordSize) {
36     _tree.add_block(p, word_size);
37   } else {
38     _small_blocks.add_block(p, word_size);
39   }
40 }
41 
42 MetaWord* FreeBlocks::remove_block(size_t requested_word_size) {
43   assert(requested_word_size >= MinWordSize,
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 > MaxSmallBlocksWordSize) {
48     p = _tree.remove_block(requested_word_size, &real_size);
49   } else {
50     p = _small_blocks.remove_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 > MinWordSize) {
57       add_block(p + requested_word_size, waste);
58     }
59   }
60   return p;
61 }
62 
63 } // namespace metaspace
64