1 /*
2 * Copyright (c) 1997, 2015, 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 "memory/virtualspace.hpp"
31 #include "utilities/macros.hpp"
32
33 // Blocks
34
35 class HeapBlock VALUE_OBJ_CLASS_SPEC {
36 friend class VMStructs;
37
38 public:
39 struct Header {
40 size_t _length; // the length in segments
41 bool _used; // Used bit
42 };
43
44 protected:
45 union {
46 Header _header;
47 int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];
48 // pad to 0 mod 8
49 };
50
51 public:
52 // Initialization
53 void initialize(size_t length) { _header._length = length; set_used(); }
54
55 // Accessors
56 void* allocated_space() const { return (void*)(this + 1); }
57 size_t length() const { return _header._length; }
58
59 // Used/free
60 void set_used() { _header._used = true; }
61 void set_free() { _header._used = false; }
62 bool free() { return !_header._used; }
63 };
64
65 class FreeBlock: public HeapBlock {
66 friend class VMStructs;
67 protected:
68 FreeBlock* _link;
69
70 public:
71 // Initialization
72 void initialize(size_t length) { HeapBlock::initialize(length); _link= NULL; }
73
74 // Merging
75 void set_length(size_t l) { _header._length = l; }
76
77 // Accessors
78 FreeBlock* link() const { return _link; }
79 void set_link(FreeBlock* link) { _link = link; }
80 };
81
82 class CodeHeap : public CHeapObj<mtCode> {
83 friend class VMStructs;
84 protected:
85 VirtualSpace _memory; // the memory holding the blocks
86 VirtualSpace _segmap; // the memory holding the segment map
87
88 size_t _number_of_committed_segments;
89 size_t _number_of_reserved_segments;
90 size_t _segment_size;
91 int _log2_segment_size;
92
93 size_t _next_segment;
94
95 FreeBlock* _freelist;
96 size_t _freelist_segments; // No. of segments in freelist
97 int _freelist_length;
98 size_t _max_allocated_capacity; // Peak capacity that was allocated during lifetime of the heap
99
100 const char* _name; // Name of the CodeHeap
101 const int _code_blob_type; // CodeBlobType it contains
102 int _blob_count; // Number of CodeBlobs
103 int _nmethod_count; // Number of nmethods
104 int _adapter_count; // Number of adapters
105 int _full_count; // Number of times the code heap was full
106
107
108 enum { free_sentinel = 0xFF };
109
110 // Helper functions
111 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
112 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
113
114 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
115 bool is_segment_unused(int val) const { return val == free_sentinel; }
116 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
117
118 void mark_segmap_as_free(size_t beg, size_t end);
119 void mark_segmap_as_used(size_t beg, size_t end);
120
121 // Freelist management helpers
122 FreeBlock* following_block(FreeBlock* b);
123 void insert_after(FreeBlock* a, FreeBlock* b);
124 bool merge_right (FreeBlock* a);
125
126 // Toplevel freelist management
127 void add_to_freelist(HeapBlock* b);
128 FreeBlock* search_freelist(size_t length);
129
130 // Iteration helpers
131 void* next_used(HeapBlock* b) const;
132 HeapBlock* first_block() const;
133 HeapBlock* next_block(HeapBlock* b) const;
134 HeapBlock* block_start(void* p) const;
135
136 // to perform additional actions on creation of executable code
137 void on_code_mapping(char* base, size_t size);
138 void clear(); // clears all heap contents
139
140 public:
141 CodeHeap(const char* name, const int code_blob_type);
142
143 // Heap extents
144 bool reserve(ReservedSpace rs, size_t committed_size, size_t segment_size);
145 bool expand_by(size_t size); // expands committed memory by size
146
147 // Memory allocation
148 void* allocate (size_t size); // Allocate 'size' bytes in the code cache or return NULL
149 void deallocate(void* p); // Deallocate memory
150 // Free the tail of segments allocated by the last call to 'allocate()' which exceed 'used_size'.
151 // ATTENTION: this is only safe to use if there was no other call to 'allocate()' after
152 // 'p' was allocated. Only intended for freeing memory which would be otherwise
153 // wasted after the interpreter generation because we don't know the interpreter size
154 // beforehand and we also can't easily relocate the interpreter to a new location.
155 void deallocate_tail(void* p, size_t used_size);
156
157 // Attributes
158 char* low_boundary() const { return _memory.low_boundary(); }
159 char* high() const { return _memory.high(); }
160 char* high_boundary() const { return _memory.high_boundary(); }
161
162 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
163 bool contains_blob(const CodeBlob* blob) const { return contains(blob->code_begin()); }
164
165 virtual void* find_start(void* p) const; // returns the block containing p or NULL
166 virtual CodeBlob* find_blob_unsafe(void* start) const;
167 size_t alignment_unit() const; // alignment of any block
168 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
169 static size_t header_size(); // returns the header size for each heap block
170
171 size_t allocated_in_freelist() const { return _freelist_segments * CodeCacheSegmentSize; }
172 int freelist_length() const { return _freelist_length; } // number of elements in the freelist
173
174 // returns the first block or NULL
175 virtual void* first() const { return next_used(first_block()); }
176 // returns the next block given a block p or NULL
177 virtual void* next(void* p) const { return next_used(next_block(block_start(p))); }
178
179 // Statistics
180 size_t capacity() const;
181 size_t max_capacity() const;
182 int allocated_segments() const;
183 size_t allocated_capacity() const;
184 size_t max_allocated_capacity() const { return _max_allocated_capacity; }
185 size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); }
186
187 // Returns true if the CodeHeap contains CodeBlobs of the given type
188 bool accepts(int code_blob_type) const { return (_code_blob_type == CodeBlobType::All) ||
189 (_code_blob_type == code_blob_type); }
190 int code_blob_type() const { return _code_blob_type; }
191
192 // Debugging / Profiling
193 const char* name() const { return _name; }
194 int blob_count() { return _blob_count; }
195 int nmethod_count() { return _nmethod_count; }
196 void set_nmethod_count(int count) { _nmethod_count = count; }
197 int adapter_count() { return _adapter_count; }
198 void set_adapter_count(int count) { _adapter_count = count; }
199 int full_count() { return _full_count; }
200 void report_full() { _full_count++; }
201
202 private:
203 size_t heap_unallocated_capacity() const;
204
205 public:
206 // Debugging
207 void verify() PRODUCT_RETURN;
208 void print() PRODUCT_RETURN;
209 };
210
211 #endif // SHARE_VM_MEMORY_HEAP_HPP