1 /*
2 * Copyright (c) 2018, 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.
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23 */
24
25 #ifndef SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_
26 #define SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_
27
28 #include "memory/virtualspace.hpp"
29 #include "memory/memRegion.hpp"
30 #include "utilities/debug.hpp"
31 #include "utilities/globalDefinitions.hpp"
32
33 class outputStream;
34
35 namespace metaspace {
36
37 class Metachunk;
38 class ChunkManager;
39 class OccupancyMap;
40
41 // A VirtualSpaceList node.
42 class VirtualSpaceNode : public CHeapObj<mtClass> {
43 friend class VirtualSpaceList;
44
45 // Link to next VirtualSpaceNode
46 VirtualSpaceNode* _next;
47
48 // Whether this node is contained in class or metaspace.
49 const bool _is_class;
50
51 // total in the VirtualSpace
52 MemRegion _reserved;
53 ReservedSpace _rs;
54 VirtualSpace _virtual_space;
55 MetaWord* _top;
56 // count of chunks contained in this VirtualSpace
57 uintx _container_count;
58
59 OccupancyMap* _occupancy_map;
60
61 // Convenience functions to access the _virtual_space
62 char* low() const { return virtual_space()->low(); }
63 char* high() const { return virtual_space()->high(); }
64
65 // The first Metachunk will be allocated at the bottom of the
66 // VirtualSpace
67 Metachunk* first_chunk() { return (Metachunk*) bottom(); }
68
69 // Committed but unused space in the virtual space
70 size_t free_words_in_vs() const;
71
72 // True if this node belongs to class metaspace.
73 bool is_class() const { return _is_class; }
74
75 // Helper function for take_from_committed: allocate padding chunks
76 // until top is at the given address.
77 void allocate_padding_chunks_until_top_is_at(MetaWord* target_top);
78
79 public:
80
81 VirtualSpaceNode(bool is_class, size_t byte_size);
82 VirtualSpaceNode(bool is_class, ReservedSpace rs) :
83 _is_class(is_class), _top(NULL), _next(NULL), _rs(rs), _container_count(0), _occupancy_map(NULL) {}
84 ~VirtualSpaceNode();
85
86 // Convenience functions for logical bottom and end
87 MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }
88 MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }
89
90 const OccupancyMap* occupancy_map() const { return _occupancy_map; }
91 OccupancyMap* occupancy_map() { return _occupancy_map; }
92
93 bool contains(const void* ptr) { return ptr >= low() && ptr < high(); }
94
95 size_t reserved_words() const { return _virtual_space.reserved_size() / BytesPerWord; }
96 size_t committed_words() const { return _virtual_space.actual_committed_size() / BytesPerWord; }
97
98 bool is_pre_committed() const { return _virtual_space.special(); }
99
100 // address of next available space in _virtual_space;
101 // Accessors
102 VirtualSpaceNode* next() { return _next; }
103 void set_next(VirtualSpaceNode* v) { _next = v; }
104
105 void set_reserved(MemRegion const v) { _reserved = v; }
106 void set_top(MetaWord* v) { _top = v; }
107
108 // Accessors
109 MemRegion* reserved() { return &_reserved; }
110 VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }
111
112 // Returns true if "word_size" is available in the VirtualSpace
113 bool is_available(size_t word_size) { return word_size <= pointer_delta(end(), _top, sizeof(MetaWord)); }
114
115 MetaWord* top() const { return _top; }
116 void inc_top(size_t word_size) { _top += word_size; }
117
118 uintx container_count() { return _container_count; }
119 void inc_container_count();
120 void dec_container_count();
121 #ifdef ASSERT
122 uintx container_count_slow();
123 void verify_container_count();
124 #endif
125
126 // used and capacity in this single entry in the list
127 size_t used_words_in_vs() const;
128 size_t capacity_words_in_vs() const;
129
130 bool initialize();
131
132 // get space from the virtual space
133 Metachunk* take_from_committed(size_t chunk_word_size);
134
135 // Allocate a chunk from the virtual space and return it.
136 Metachunk* get_chunk_vs(size_t chunk_word_size);
137
138 // Expands/shrinks the committed space in a virtual space. Delegates
139 // to Virtualspace
140 bool expand_by(size_t min_words, size_t preferred_words);
141
142 // In preparation for deleting this node, remove all the chunks
143 // in the node from any freelist.
144 void purge(ChunkManager* chunk_manager);
145
146 // If an allocation doesn't fit in the current node a new node is created.
147 // Allocate chunks out of the remaining committed space in this node
148 // to avoid wasting that memory.
149 // This always adds up because all the chunk sizes are multiples of
150 // the smallest chunk size.
151 void retire(ChunkManager* chunk_manager);
152
153 void print_on(outputStream* st) const { print_on(st, K); }
154 void print_on(outputStream* st, size_t scale) const;
155 void print_map(outputStream* st, bool is_class) const;
156
157 // Debug support
158 DEBUG_ONLY(void mangle();)
159 // Verify counters, all chunks in this list node and the occupancy map.
160 DEBUG_ONLY(void verify();)
161 // Verify that all free chunks in this node are ideally merged
162 // (there not should be multiple small chunks where a large chunk could exist.)
163 DEBUG_ONLY(void verify_free_chunks_are_ideally_merged();)
164
165 };
166
167 } // namespace metaspace
168
169 #endif /* SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP_ */