1 /*
2 * Copyright (c) 1997, 2013, 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 int _freelist_length;
97 size_t _max_allocated_capacity; // Peak capacity that was allocated during lifetime of the heap
98
99 const char* _name; // Name of the CodeHeap
100 const int _code_blob_type; // CodeBlobType it contains
101 bool _was_full;
102
103 enum { free_sentinel = 0xFF };
104
105 // Helper functions
106 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
107 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
108
109 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
110 bool is_segment_unused(int val) const { return val == free_sentinel; }
111 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
112
113 void mark_segmap_as_free(size_t beg, size_t end);
114 void mark_segmap_as_used(size_t beg, size_t end);
115
116 // Freelist management helpers
117 FreeBlock* following_block(FreeBlock* b);
118 void insert_after(FreeBlock* a, FreeBlock* b);
119 bool merge_right (FreeBlock* a);
120
121 // Toplevel freelist management
122 void add_to_freelist(HeapBlock* b);
123 FreeBlock* search_freelist(size_t length, bool is_critical);
124
125 // Iteration helpers
126 void* next_free(HeapBlock* b) const;
127 HeapBlock* first_block() const;
128 HeapBlock* next_block(HeapBlock* b) const;
129 HeapBlock* block_start(void* p) const;
130
131 // to perform additional actions on creation of executable code
132 void on_code_mapping(char* base, size_t size);
133 void clear(); // clears all heap contents
134
135 public:
136 CodeHeap(const char* name, const int code_blob_type);
137
138 // Heap extents
139 bool reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);
140 bool expand_by(size_t size); // expands committed memory by size
141
142 // Memory allocation
143 void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
144 void deallocate(void* p); // deallocates a block
145
146 // Attributes
147 char* low_boundary() const { return _memory.low_boundary (); }
148 char* high() const { return _memory.high(); }
149 char* high_boundary() const { return _memory.high_boundary(); }
150
151 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
152 void* find_start(void* p) const; // returns the block containing p or NULL
153 size_t alignment_unit() const; // alignment of any block
154 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
155 static size_t header_size(); // returns the header size for each heap block
156
157 size_t allocated_in_freelist() const { return _freelist_segments * CodeCacheSegmentSize; }
158 int freelist_length() const { return _freelist_length; } // number of elements in the freelist
159
160 // returns the first block or NULL
161 void* first() const { return next_free(first_block()); }
162 // returns the next block given a block p or NULL
163 void* next(void* p) const { return next_free(next_block(block_start(p))); }
164
165 // Statistics
166 size_t capacity() const;
167 size_t max_capacity() const;
168 int allocated_segments() const;
169 size_t allocated_capacity() const;
170 size_t max_allocated_capacity() const { return _max_allocated_capacity; }
171 size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); }
172
173 // Returns true if the CodeHeap contains CodeBlobs of the given type
174 bool accepts(int code_blob_type) const { return (_code_blob_type == code_blob_type); }
175
176 // Debugging / Profiling
177 const char* name() const { return _name; }
178 bool was_full() { return _was_full; }
179 void report_full() { _was_full = true; }
180
181 private:
182 size_t heap_unallocated_capacity() const;
183
184 public:
185 // Debugging
186 void verify() PRODUCT_RETURN;
187 void print() PRODUCT_RETURN;
188 };
189
190 #endif // SHARE_VM_MEMORY_HEAP_HPP