Wed, 26 Jun 2013 16:58:37 +0200
8013590: NPG: Add a memory pool MXBean for Metaspace
Reviewed-by: jmasa, mgerdin
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
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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.
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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23 */
25 #ifndef SHARE_VM_MEMORY_HEAP_HPP
26 #define SHARE_VM_MEMORY_HEAP_HPP
28 #include "memory/allocation.hpp"
29 #include "runtime/virtualspace.hpp"
31 // Blocks
33 class HeapBlock VALUE_OBJ_CLASS_SPEC {
34 friend class VMStructs;
36 public:
37 struct Header {
38 size_t _length; // the length in segments
39 bool _used; // Used bit
40 };
42 protected:
43 union {
44 Header _header;
45 int64_t _padding[ (sizeof(Header) + sizeof(int64_t)-1) / sizeof(int64_t) ];
46 // pad to 0 mod 8
47 };
49 public:
50 // Initialization
51 void initialize(size_t length) { _header._length = length; set_used(); }
53 // Accessors
54 void* allocated_space() const { return (void*)(this + 1); }
55 size_t length() const { return _header._length; }
57 // Used/free
58 void set_used() { _header._used = true; }
59 void set_free() { _header._used = false; }
60 bool free() { return !_header._used; }
61 };
63 class FreeBlock: public HeapBlock {
64 friend class VMStructs;
65 protected:
66 FreeBlock* _link;
68 public:
69 // Initialization
70 void initialize(size_t length) { HeapBlock::initialize(length); _link= NULL; }
72 // Merging
73 void set_length(size_t l) { _header._length = l; }
75 // Accessors
76 FreeBlock* link() const { return _link; }
77 void set_link(FreeBlock* link) { _link = link; }
78 };
80 class CodeHeap : public CHeapObj<mtCode> {
81 friend class VMStructs;
82 private:
83 VirtualSpace _memory; // the memory holding the blocks
84 VirtualSpace _segmap; // the memory holding the segment map
86 size_t _number_of_committed_segments;
87 size_t _number_of_reserved_segments;
88 size_t _segment_size;
89 int _log2_segment_size;
91 size_t _next_segment;
93 FreeBlock* _freelist;
94 size_t _freelist_segments; // No. of segments in freelist
96 // Helper functions
97 size_t size_to_segments(size_t size) const { return (size + _segment_size - 1) >> _log2_segment_size; }
98 size_t segments_to_size(size_t number_of_segments) const { return number_of_segments << _log2_segment_size; }
100 size_t segment_for(void* p) const { return ((char*)p - _memory.low()) >> _log2_segment_size; }
101 HeapBlock* block_at(size_t i) const { return (HeapBlock*)(_memory.low() + (i << _log2_segment_size)); }
103 void mark_segmap_as_free(size_t beg, size_t end);
104 void mark_segmap_as_used(size_t beg, size_t end);
106 // Freelist management helpers
107 FreeBlock* following_block(FreeBlock *b);
108 void insert_after(FreeBlock* a, FreeBlock* b);
109 void merge_right (FreeBlock* a);
111 // Toplevel freelist management
112 void add_to_freelist(HeapBlock *b);
113 FreeBlock* search_freelist(size_t length, bool is_critical);
115 // Iteration helpers
116 void* next_free(HeapBlock* b) const;
117 HeapBlock* first_block() const;
118 HeapBlock* next_block(HeapBlock* b) const;
119 HeapBlock* block_start(void* p) const;
121 // to perform additional actions on creation of executable code
122 void on_code_mapping(char* base, size_t size);
124 public:
125 CodeHeap();
127 // Heap extents
128 bool reserve(size_t reserved_size, size_t committed_size, size_t segment_size);
129 void release(); // releases all allocated memory
130 bool expand_by(size_t size); // expands commited memory by size
131 void shrink_by(size_t size); // shrinks commited memory by size
132 void clear(); // clears all heap contents
134 // Memory allocation
135 void* allocate (size_t size, bool is_critical); // allocates a block of size or returns NULL
136 void deallocate(void* p); // deallocates a block
138 // Attributes
139 char* low_boundary() const { return _memory.low_boundary (); }
140 char* high() const { return _memory.high(); }
141 char* high_boundary() const { return _memory.high_boundary(); }
143 bool contains(const void* p) const { return low_boundary() <= p && p < high(); }
144 void* find_start(void* p) const; // returns the block containing p or NULL
145 size_t alignment_unit() const; // alignment of any block
146 size_t alignment_offset() const; // offset of first byte of any block, within the enclosing alignment unit
147 static size_t header_size(); // returns the header size for each heap block
149 // Iteration
151 // returns the first block or NULL
152 void* first() const { return next_free(first_block()); }
153 // returns the next block given a block p or NULL
154 void* next(void* p) const { return next_free(next_block(block_start(p))); }
156 // Statistics
157 size_t capacity() const;
158 size_t max_capacity() const;
159 size_t allocated_capacity() const;
160 size_t unallocated_capacity() const { return max_capacity() - allocated_capacity(); }
162 private:
163 size_t heap_unallocated_capacity() const;
165 public:
166 // Debugging
167 void verify();
168 void print() PRODUCT_RETURN;
169 };
171 #endif // SHARE_VM_MEMORY_HEAP_HPP