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
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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 ReservedSpace _rs;
53 VirtualSpace _virtual_space;
54 MetaWord* _top;
55 // count of chunks contained in this VirtualSpace
56 uintx _container_count;
57
58 OccupancyMap* _occupancy_map;
59
60 // Convenience functions to access the _virtual_space
61 char* low() const { return virtual_space()->low(); }
62 char* high() const { return virtual_space()->high(); }
63 char* low_boundary() const { return virtual_space()->low_boundary(); }
64 char* high_boundary() const { return virtual_space()->high_boundary(); }
65
66 // The first Metachunk will be allocated at the bottom of the
67 // VirtualSpace
68 Metachunk* first_chunk() { return (Metachunk*) bottom(); }
69
70 // Committed but unused space in the virtual space
71 size_t free_words_in_vs() const;
72
73 // True if this node belongs to class metaspace.
74 bool is_class() const { return _is_class; }
75
76 // Helper function for take_from_committed: allocate padding chunks
77 // until top is at the given address.
78 void allocate_padding_chunks_until_top_is_at(MetaWord* target_top);
79
80 public:
81
82 VirtualSpaceNode(bool is_class, size_t byte_size);
83 VirtualSpaceNode(bool is_class, ReservedSpace rs) :
84 _next(NULL), _is_class(is_class), _rs(rs), _top(NULL), _container_count(0), _occupancy_map(NULL) {}
85 ~VirtualSpaceNode();
86
87 // Convenience functions for logical bottom and (committed) end
88 MetaWord* bottom() const { return (MetaWord*) _virtual_space.low(); }
89 MetaWord* end() const { return (MetaWord*) _virtual_space.high(); }
90
91 const OccupancyMap* occupancy_map() const { return _occupancy_map; }
92 OccupancyMap* occupancy_map() { return _occupancy_map; }
93
94 bool contains(const void* ptr) { return ptr >= low() && ptr < high(); }
95
96 size_t reserved_words() const { return _virtual_space.reserved_size() / BytesPerWord; }
97 size_t committed_words() const { return _virtual_space.actual_committed_size() / BytesPerWord; }
98
99 bool is_pre_committed() const { return _virtual_space.special(); }
100
101 // address of next available space in _virtual_space;
102 // Accessors
103 VirtualSpaceNode* next() { return _next; }
104 void set_next(VirtualSpaceNode* v) { _next = v; }
105
106 void set_top(MetaWord* v) { _top = v; }
107
108 // Accessors
109 VirtualSpace* virtual_space() const { return (VirtualSpace*) &_virtual_space; }
110
111 // Returns true if "word_size" is available in the VirtualSpace
112 bool is_available(size_t word_size) { return word_size <= pointer_delta(end(), _top, sizeof(MetaWord)); }
113
114 MetaWord* top() const { return _top; }
115 void inc_top(size_t word_size) { _top += word_size; }
116
117 uintx container_count() { return _container_count; }
118 void inc_container_count();
119 void dec_container_count();
120
121 // used and capacity in this single entry in the list
122 size_t used_words_in_vs() const;
123 size_t capacity_words_in_vs() const;
124
125 bool initialize();
126
127 // get space from the virtual space
128 Metachunk* take_from_committed(size_t chunk_word_size);
129
130 // Allocate a chunk from the virtual space and return it.
131 Metachunk* get_chunk_vs(size_t chunk_word_size);
132
133 // Expands the committed space by at least min_words words.
134 bool expand_by(size_t min_words, size_t preferred_words);
135
136 // In preparation for deleting this node, remove all the chunks
137 // in the node from any freelist.
138 void purge(ChunkManager* chunk_manager);
139
140 // If an allocation doesn't fit in the current node a new node is created.
141 // Allocate chunks out of the remaining committed space in this node
142 // to avoid wasting that memory.
143 // This always adds up because all the chunk sizes are multiples of
144 // the smallest chunk size.
145 void retire(ChunkManager* chunk_manager);
146
147 void print_on(outputStream* st) const { print_on(st, K); }
148 void print_on(outputStream* st, size_t scale) const;
149 void print_map(outputStream* st, bool is_class) const;
150
151 // Debug support
152 DEBUG_ONLY(void mangle();)
153 // Verify counters and basic structure. Slow mode: verify all chunks in depth and occupancy map.
154 DEBUG_ONLY(void verify(bool slow);)
155 // Verify that all free chunks in this node are ideally merged
156 // (there should not be multiple small chunks where a large chunk could exist.)
157 DEBUG_ONLY(void verify_free_chunks_are_ideally_merged();)
158
159 };
160
161 } // namespace metaspace
162
163 #endif // SHARE_MEMORY_METASPACE_VIRTUALSPACENODE_HPP