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
6 * under the terms of the GNU General Public License version 2 only, as
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.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #ifndef SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
26 #define SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP
27
28 #include "memory/allocation.hpp"
29 #include "memory/metaspace.hpp"
30 #include "memory/metaspace/blockFreelist.hpp"
31 #include "memory/metaspace/chunkAllocSequence.hpp"
32 #include "memory/metaspace/chunkManager.hpp"
33 #include "memory/metaspace/metachunk.hpp"
34 #include "memory/metaspace/metaspaceCommon.hpp"
35
36 class outputStream;
37 class Mutex;
38
39 namespace metaspace {
40
41 class SpaceManagerStatistics;
42
43 // The SpaceManager:
44 // - keeps a list of chunks-in-use by the class loader, as well as a current chunk used
45 // to allocate from
46 // - keeps a dictionary of free MetaBlocks. Those can be remnants of a retired chunk or
47 // allocations which were not needed anymore for some reason (e.g. releasing half-allocated
48 // structures when class loading fails)
49
50 class SpaceManager : public CHeapObj<mtClass> {
51
52 // Lock handed down from the associated ClassLoaderData.
53 // Protects allocations from this space.
54 Mutex* const _lock;
55
56 // The chunk manager to allocate chunks from.
57 ChunkManager* const _chunk_manager;
58
59 // The chunk allocation strategy to use.
60 const ChunkAllocSequence* const _chunk_alloc_sequence;
61
62 // List of chunks in use by this SpaceManager. Allocations
63 // are done from the current chunk. The list is used for deallocating
64 // chunks when the SpaceManager is freed.
65 MetachunkList _chunks;
66 Metachunk* _current_chunk;
67
68 // Prematurely released metablocks.
69 BlockFreelist* _block_freelist;
70
71
72 // Statistics
73
74 // Running counters.
75 // Note: capacity = used + free + waste + overhead. We do not keep running counters for
76 // free and waste. Their sum can be deduced from the three other values.
77 // size_t _overhead_words;
78 // size_t _capacity_words;
79 // size_t _used_words;
80 uintx _num_chunks_by_level[chklvl::NUM_CHUNK_LEVELS];
81 uintx _num_chunks_total;
82
83
84 Mutex* lock() const { return _lock; }
85 ChunkManager* chunk_manager() const { return _chunk_manager; }
86 const ChunkAllocSequence* chunk_alloc_sequence() const { return _chunk_alloc_sequence; }
87
88 BlockFreelist* block_freelist() const { return _block_freelist; }
89 void create_block_freelist();
90
91 // The current chunk is unable to service a request. The remainder of the chunk is
92 // chopped into blocks and fed into the _block_freelists, in the hope of later reuse.
93 void retire_current_chunk();
94
95 // Given a requested word size, will allocate a chunk large enough to at least fit that
96 // size, but may be larger according to the rules in the ChunkAllocSequence.
97 // Updates counters and adds the chunk to the head of the chunk list.
98 Metachunk* allocate_chunk_to_fit(size_t requested_word_size);
99
100 public:
101
102 SpaceManager(ChunkManager* chunk_manager, const ChunkAllocSequence* alloc_sequence, Mutex* lock);
103
104 ~SpaceManager();
105
106 // Allocate memory from Metaspace. Will attempt to allocate from the _block_freelists,
107 // failing that, from the current chunk; failing that, attempt to get a new chunk from
108 // the associated ChunkManager.
109 MetaWord* allocate(size_t word_size);
110
111 // Prematurely returns a metaspace allocation to the _block_freelists because it is not
112 // needed anymore.
113 void deallocate(MetaWord* p, size_t word_size);
114
115 // Update statistics. This walks all in-use chunks.
116 void add_to_statistics(SpaceManagerStatistics* out) const;
117
118 // Run verifications. slow=true: verify chunk-internal integrity too.
119 DEBUG_ONLY(void locked_verify(bool slow) const;)
120
121 };
122
123 } // namespace metaspace
124
125 #endif // SHARE_MEMORY_METASPACE_SPACEMANAGER_HPP