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
35class 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
65class 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
82class 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
151  // Attributes
152  char* low_boundary() const                     { return _memory.low_boundary (); }
153  char* high() const                             { return _memory.high(); }
154  char* high_boundary() const                    { return _memory.high_boundary(); }
155
156  virtual bool contains(const void* p) const     { return low_boundary() <= p && p < high(); }
157  virtual bool contains_blob(const CodeBlob* blob) const { return low_boundary() <= (char*) blob && (char*) blob < high(); }
158
159  virtual void* find_start(void* p)     const;   // returns the block containing p or NULL
160  virtual CodeBlob* find_blob_unsafe(void* start) const;
161  size_t alignment_unit()       const;           // alignment of any block
162  size_t alignment_offset()     const;           // offset of first byte of any block, within the enclosing alignment unit
163  static size_t header_size();                   // returns the header size for each heap block
164
165  size_t allocated_in_freelist() const           { return _freelist_segments * CodeCacheSegmentSize; }
166  int    freelist_length()       const           { return _freelist_length; } // number of elements in the freelist
167
168  // returns the first block or NULL
169  virtual void* first() const                    { return next_used(first_block()); }
170  // returns the next block given a block p or NULL
171  virtual void* next(void* p) const              { return next_used(next_block(block_start(p))); }
172
173  // Statistics
174  size_t capacity() const;
175  size_t max_capacity() const;
176  int    allocated_segments() const;
177  size_t allocated_capacity() const;
178  size_t max_allocated_capacity() const          { return _max_allocated_capacity; }
179  size_t unallocated_capacity() const            { return max_capacity() - allocated_capacity(); }
180
181  // Returns true if the CodeHeap contains CodeBlobs of the given type
182  bool accepts(int code_blob_type) const         { return (_code_blob_type == CodeBlobType::All) ||
183                                                          (_code_blob_type == code_blob_type); }
184  int code_blob_type() const                     { return _code_blob_type; }
185
186  // Debugging / Profiling
187  const char* name() const                       { return _name; }
188  int         blob_count()                       { return _blob_count; }
189  int         nmethod_count()                    { return _nmethod_count; }
190  void    set_nmethod_count(int count)           {        _nmethod_count = count; }
191  int         adapter_count()                    { return _adapter_count; }
192  void    set_adapter_count(int count)           {        _adapter_count = count; }
193  int         full_count()                       { return _full_count; }
194  void        report_full()                      {        _full_count++; }
195
196private:
197  size_t heap_unallocated_capacity() const;
198
199public:
200  // Debugging
201  void verify() PRODUCT_RETURN;
202  void print()  PRODUCT_RETURN;
203};
204
205#endif // SHARE_VM_MEMORY_HEAP_HPP
206