1 /*
2 * Copyright (c) 2018, 2019, 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
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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.
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23 */
24
25 #ifndef SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP
26 #define SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP
27
28 #include "memory/allocation.hpp"
29 #include "memory/binaryTreeDictionary.hpp"
30 #include "memory/freeList.hpp"
31 #include "memory/metaspace/metachunk.hpp"
32 #include "memory/metaspace/metaspaceStatistics.hpp"
33 #include "memory/metaspaceChunkFreeListSummary.hpp"
34 #include "utilities/globalDefinitions.hpp"
35
36 class ChunkManagerTestAccessor;
37
38 namespace metaspace {
39
40 typedef class FreeList<Metachunk> ChunkList;
41 typedef BinaryTreeDictionary<Metachunk, FreeList<Metachunk> > ChunkTreeDictionary;
42
43 // Manages the global free lists of chunks.
44 class ChunkManager : public CHeapObj<mtInternal> {
45 friend class ::ChunkManagerTestAccessor;
46
47 // Free list of chunks of different sizes.
48 // SpecializedChunk
49 // SmallChunk
50 // MediumChunk
51 ChunkList _free_chunks[NumberOfFreeLists];
52
53 // Whether or not this is the class chunkmanager.
54 const bool _is_class;
55
56 // Return non-humongous chunk list by its index.
57 ChunkList* free_chunks(ChunkIndex index);
58
59 // Returns non-humongous chunk list for the given chunk word size.
60 ChunkList* find_free_chunks_list(size_t word_size);
61
62 // HumongousChunk
63 ChunkTreeDictionary _humongous_dictionary;
64
65 // Returns the humongous chunk dictionary.
66 ChunkTreeDictionary* humongous_dictionary() { return &_humongous_dictionary; }
67 const ChunkTreeDictionary* humongous_dictionary() const { return &_humongous_dictionary; }
68
69 // Size, in metaspace words, of all chunks managed by this ChunkManager
70 size_t _free_chunks_total;
71 // Number of chunks in this ChunkManager
72 size_t _free_chunks_count;
73
74 // Update counters after a chunk was added or removed removed.
75 void account_for_added_chunk(const Metachunk* c);
76 void account_for_removed_chunk(const Metachunk* c);
77
78 // Given a pointer to a chunk, attempts to merge it with neighboring
79 // free chunks to form a bigger chunk. Returns true if successful.
80 bool attempt_to_coalesce_around_chunk(Metachunk* chunk, ChunkIndex target_chunk_type);
81
82 // Helper for chunk merging:
83 // Given an address range with 1-n chunks which are all supposed to be
84 // free and hence currently managed by this ChunkManager, remove them
85 // from this ChunkManager and mark them as invalid.
86 // - This does not correct the occupancy map.
87 // - This does not adjust the counters in ChunkManager.
88 // - Does not adjust container count counter in containing VirtualSpaceNode.
89 // Returns number of chunks removed.
90 int remove_chunks_in_area(MetaWord* p, size_t word_size);
91
92 // Helper for chunk splitting: given a target chunk size and a larger free chunk,
93 // split up the larger chunk into n smaller chunks, at least one of which should be
94 // the target chunk of target chunk size. The smaller chunks, including the target
95 // chunk, are returned to the freelist. The pointer to the target chunk is returned.
96 // Note that this chunk is supposed to be removed from the freelist right away.
97 Metachunk* split_chunk(size_t target_chunk_word_size, Metachunk* chunk);
98
99 public:
100
101 ChunkManager(bool is_class);
102
103 // Add or delete (return) a chunk to the global freelist.
104 Metachunk* chunk_freelist_allocate(size_t word_size);
105
106 // Map a size to a list index assuming that there are lists
107 // for special, small, medium, and humongous chunks.
108 ChunkIndex list_index(size_t size);
109
110 // Map a given index to the chunk size.
111 size_t size_by_index(ChunkIndex index) const;
112
113 bool is_class() const { return _is_class; }
114
115 // Convenience accessors.
116 size_t medium_chunk_word_size() const { return size_by_index(MediumIndex); }
117 size_t small_chunk_word_size() const { return size_by_index(SmallIndex); }
118 size_t specialized_chunk_word_size() const { return size_by_index(SpecializedIndex); }
119
120 // Take a chunk from the ChunkManager. The chunk is expected to be in
121 // the chunk manager (the freelist if non-humongous, the dictionary if
122 // humongous).
123 void remove_chunk(Metachunk* chunk);
124
125 // Return a single chunk of type index to the ChunkManager.
126 void return_single_chunk(Metachunk* chunk);
127
128 // Add the simple linked list of chunks to the freelist of chunks
129 // of type index.
130 void return_chunk_list(Metachunk* chunk);
131
132 // Total of the space in the free chunks list
133 size_t free_chunks_total_words() const { return _free_chunks_total; }
134 size_t free_chunks_total_bytes() const { return free_chunks_total_words() * BytesPerWord; }
135
136 // Number of chunks in the free chunks list
137 size_t free_chunks_count() const { return _free_chunks_count; }
138
139 // Remove from a list by size. Selects list based on size of chunk.
140 Metachunk* free_chunks_get(size_t chunk_word_size);
141
142 #define index_bounds_check(index) \
143 assert(is_valid_chunktype(index), "Bad index: %d", (int) index)
144
145 size_t num_free_chunks(ChunkIndex index) const {
146 index_bounds_check(index);
147
148 if (index == HumongousIndex) {
149 return _humongous_dictionary.total_free_blocks();
150 }
151
152 ssize_t count = _free_chunks[index].count();
153 return count == -1 ? 0 : (size_t) count;
154 }
155
156 size_t size_free_chunks_in_bytes(ChunkIndex index) const {
157 index_bounds_check(index);
158
159 size_t word_size = 0;
160 if (index == HumongousIndex) {
161 word_size = _humongous_dictionary.total_size();
162 } else {
163 const size_t size_per_chunk_in_words = _free_chunks[index].size();
164 word_size = size_per_chunk_in_words * num_free_chunks(index);
165 }
166
167 return word_size * BytesPerWord;
168 }
169
170 MetaspaceChunkFreeListSummary chunk_free_list_summary() const {
171 return MetaspaceChunkFreeListSummary(num_free_chunks(SpecializedIndex),
172 num_free_chunks(SmallIndex),
173 num_free_chunks(MediumIndex),
174 num_free_chunks(HumongousIndex),
175 size_free_chunks_in_bytes(SpecializedIndex),
176 size_free_chunks_in_bytes(SmallIndex),
177 size_free_chunks_in_bytes(MediumIndex),
178 size_free_chunks_in_bytes(HumongousIndex));
179 }
180
181 #ifdef ASSERT
182 // Debug support
183 // Verify free list integrity. slow=true: verify chunk-internal integrity too.
184 void verify(bool slow) const;
185 void locked_verify(bool slow) const;
186 #endif
187
188 void locked_print_free_chunks(outputStream* st);
189
190 // Fill in current statistic values to the given statistics object.
191 void collect_statistics(ChunkManagerStatistics* out) const;
192
193 };
194
195 } // namespace metaspace
196
197
198 #endif // SHARE_MEMORY_METASPACE_CHUNKMANAGER_HPP