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.
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24 */
25
26 #ifndef SHARE_MEMORY_METASPACE_CHUNKLEVEL_HPP
27 #define SHARE_MEMORY_METASPACE_CHUNKLEVEL_HPP
28
29 #include "utilities/globalDefinitions.hpp"
30
31 // Constants for the chunk levels and some utility functions.
32
33 class outputStream;
34
35 namespace metaspace {
36
37
38 // Chunks are managed by a binary buddy allocator.
39
40 // Chunk sizes range from 1K to 4MB (64bit).
41 //
42
43 // Each chunk has a level; the level corresponds to its position in the tree
44 // and describes its size.
45 //
46 // The largest chunks are called root chunks, of 4MB in size, and have level 0.
47 // From there on it goes:
48 //
49 // size level
50 // 4MB 0
51 // 2MB 1
52 // 1MB 2
53 // 512K 3
54 // 256K 4
55 // 128K 5
56 // 64K 6
57 // 32K 7
58 // 16K 8
59 // 8K 9
60 // 4K 10
61 // 2K 11
62 // 1K 12
63
64 // Metachunk level (must be signed)
65 typedef signed char chunklevel_t;
66
67 #define CHKLVL_FORMAT "lv%.2d"
68
69 namespace chunklevel {
70
71 static const size_t MAX_CHUNK_BYTE_SIZE = 4 * M;
72 static const int NUM_CHUNK_LEVELS = 13;
73 static const size_t MIN_CHUNK_BYTE_SIZE = (MAX_CHUNK_BYTE_SIZE >> ((size_t)NUM_CHUNK_LEVELS - 1));
74
75 static const size_t MIN_CHUNK_WORD_SIZE = MIN_CHUNK_BYTE_SIZE / sizeof(MetaWord);
76 static const size_t MAX_CHUNK_WORD_SIZE = MAX_CHUNK_BYTE_SIZE / sizeof(MetaWord);
77
78 static const chunklevel_t ROOT_CHUNK_LEVEL = 0;
79
80 static const chunklevel_t HIGHEST_CHUNK_LEVEL = NUM_CHUNK_LEVELS - 1;
81 static const chunklevel_t LOWEST_CHUNK_LEVEL = 0;
82
83 static const chunklevel_t INVALID_CHUNK_LEVEL = (chunklevel_t) -1;
84
85 inline bool is_valid_level(chunklevel_t level) {
86 return level >= LOWEST_CHUNK_LEVEL &&
87 level <= HIGHEST_CHUNK_LEVEL;
88 }
89
90 inline void check_valid_level(chunklevel_t lvl) {
91 assert(is_valid_level(lvl), "invalid level (%d)", (int)lvl);
92 }
93
94 // Given a level return the chunk size, in words.
95 inline size_t word_size_for_level(chunklevel_t level) {
96 return (MAX_CHUNK_BYTE_SIZE >> level) / BytesPerWord;
97 }
98
99 // Given an arbitrary word size smaller than the highest chunk size,
100 // return the highest chunk level able to hold this size.
101 // Returns INVALID_CHUNK_LEVEL if no fitting level can be found.
102 chunklevel_t level_fitting_word_size(size_t word_size);
103
104 // Shorthands to refer to exact sizes
105 static const chunklevel_t CHUNK_LEVEL_4M = ROOT_CHUNK_LEVEL;
106 static const chunklevel_t CHUNK_LEVEL_2M = (ROOT_CHUNK_LEVEL + 1);
107 static const chunklevel_t CHUNK_LEVEL_1M = (ROOT_CHUNK_LEVEL + 2);
108 static const chunklevel_t CHUNK_LEVEL_512K = (ROOT_CHUNK_LEVEL + 3);
109 static const chunklevel_t CHUNK_LEVEL_256K = (ROOT_CHUNK_LEVEL + 4);
110 static const chunklevel_t CHUNK_LEVEL_128K = (ROOT_CHUNK_LEVEL + 5);
111 static const chunklevel_t CHUNK_LEVEL_64K = (ROOT_CHUNK_LEVEL + 6);
112 static const chunklevel_t CHUNK_LEVEL_32K = (ROOT_CHUNK_LEVEL + 7);
113 static const chunklevel_t CHUNK_LEVEL_16K = (ROOT_CHUNK_LEVEL + 8);
114 static const chunklevel_t CHUNK_LEVEL_8K = (ROOT_CHUNK_LEVEL + 9);
115 static const chunklevel_t CHUNK_LEVEL_4K = (ROOT_CHUNK_LEVEL + 10);
116 static const chunklevel_t CHUNK_LEVEL_2K = (ROOT_CHUNK_LEVEL + 11);
117 static const chunklevel_t CHUNK_LEVEL_1K = (ROOT_CHUNK_LEVEL + 12);
118
119 STATIC_ASSERT(CHUNK_LEVEL_1K == HIGHEST_CHUNK_LEVEL);
120 STATIC_ASSERT(CHUNK_LEVEL_4M == LOWEST_CHUNK_LEVEL);
121 STATIC_ASSERT(ROOT_CHUNK_LEVEL == LOWEST_CHUNK_LEVEL);
122
123 /////////////////////////////////////////////////////////
124 // print helpers
125 void print_chunk_size(outputStream* st, chunklevel_t lvl);
126
127
128 } // namespace chunklevel
129
130 } // namespace metaspace
131
132 #endif // SHARE_MEMORY_METASPACE_CHUNKLEVEL_HPP