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