1 /*
2 * Copyright (c) 1997, 2012, 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_VM_MEMORY_HEAP_HPP
26 #define SHARE_VM_MEMORY_HEAP_HPP
27
28 #include "code/codeBlob.hpp"
29 #include "memory/allocation.hpp"
30 #include "runtime/virtualspace.hpp"
31
32 // Blocks
33
34 class HeapBlock VALUE_OBJ_CLASS_SPEC {
35 friend class VMStructs;
36
37 public:
38 struct Header {
39 size_t _length; // the length in segments
40 bool _used; // Used bit
41 };
42
43 protected:
44 union {
45 Header _header;
46 int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];
47 // pad to 0 mod 8
48 };
49
50 public:
51 // Initialization
52 void initialize(size_t length) { _header._length = length; set_used(); }
53
54 // Accessors
55 void* allocated_space() const { return (void*)(this + 1); }
56 size_t length() const { return _header._length; }
57
58 // Used/free
59 void set_used() { _header._used = true; }
60 void set_free() { _header._used = false; }
61 bool free() { return !_header._used; }
62 };
63
64 class FreeBlock: public HeapBlock {
65 friend class VMStructs;
66 protected:
67 FreeBlock* _link;
68
69 public:
70 // Initialization
71 void initialize(size_t length) { HeapBlock::initialize(length); _link= NULL; }
72
73 // Merging
74 void set_length(size_t l) { _header._length = l; }
75
76 // Accessors
77 FreeBlock* link() const { return _link; }
78 void set_link(FreeBlock* link) { _link = link; }
79 };
80
81 class CodeHeap : public CHeapObj<mtCode> {
82 friend class VMStructs;
83 private:
84 VirtualSpace _memory; // the memory holding the blocks
85 VirtualSpace _segmap; // the memory holding the segment map
86
87 size_t _number_of_committed_segments;
88 size_t _number_of_reserved_segments;
89 size_t _segment_size;
90 int _log2_segment_size;
91
92 size_t _next_segment;
93
94 FreeBlock* _freelist;
95 size_t _freelist_segments; // No. of segments in freelist
96 size_t _max_allocated_capacity; // Peak capacity that was allocated during lifetime of the heap
97
98 const char* _name; // Name of the CodeHeap
99 const int _code_blob_type; // CodeBlobType it contains
100 bool _was_full; // True if CodeHeap was full during runtime
101
102 // Helper functions
103 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
104 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
105
106 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
107 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
108
109 void mark_segmap_as_free(size_t beg, size_t end);
110 void mark_segmap_as_used(size_t beg, size_t end);
111
112 // Freelist management helpers
113 FreeBlock* following_block(FreeBlock *b);
114 void insert_after(FreeBlock* a, FreeBlock* b);
115 void merge_right (FreeBlock* a);
116
117 // Toplevel freelist management
118 void add_to_freelist(HeapBlock *b);
119 FreeBlock* search_freelist(size_t length, bool is_critical);
120
121 // Iteration helpers
122 void* next_free(HeapBlock* b) const;
123 HeapBlock* first_block() const;
124 HeapBlock* next_block(HeapBlock* b) const;
125 HeapBlock* block_start(void* p) const;
126
127 // to perform additional actions on creation of executable code
128 void on_code_mapping(char* base, size_t size);
129
130 public:
131 CodeHeap(const char* name, const int code_blob_type);
132
133 // Heap extents
134 bool reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);
135 void release(); // releases all allocated memory
136 bool expand_by(size_t size); // expands commited memory by size
137 void shrink_by(size_t size); // shrinks commited memory by size
138 void clear(); // clears all heap contents
139
140 // Memory allocation
141 void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
142 void deallocate(void* p); // deallocates a block
143
144 // Attributes
145 char* low_boundary() const { return _memory.low_boundary (); }
146 char* high() const { return _memory.high(); }
147 char* high_boundary() const { return _memory.high_boundary(); }
148
149 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
150 void* find_start(void* p) const; // returns the block containing p or NULL
151 size_t alignment_unit() const; // alignment of any block
152 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
153 static size_t header_size(); // returns the header size for each heap block
154
155 // Iteration
156
157 // returns the first block or NULL
158 void* first() const { return next_free(first_block()); }
159 // returns the next block given a block p or NULL
160 void* next(void* p) const { return next_free(next_block(block_start(p))); }
161
162 // Statistics
163 size_t capacity() const;
164 size_t max_capacity() const;
165 size_t allocated_capacity() const;
166 size_t max_allocated_capacity() const { return _max_allocated_capacity; }
167 size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); }
168
169 // Returns true if the CodeHeap contains CodeBlobs of the given type
170 bool accepts(int code_blob_type) const { return (_code_blob_type == code_blob_type); }
171
172 // Debugging / Profiling
173 const char* name() const { return _name; }
174 bool was_full() { return _was_full; }
175 void report_full() { _was_full = true; }
176
177 private:
178 size_t heap_unallocated_capacity() const;
179
180 public:
181 // Debugging
182 void verify();
183 void print() PRODUCT_RETURN;
184 };
185
186 #endif // SHARE_VM_MEMORY_HEAP_HPP