psVirtualspace.hpp revision 8413:92457dfb91bd 
1/*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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24
25#ifndef SHARE_VM_GC_PARALLEL_PSVIRTUALSPACE_HPP
26#define SHARE_VM_GC_PARALLEL_PSVIRTUALSPACE_HPP
27
28#include "memory/virtualspace.hpp"
29
30// VirtualSpace for the parallel scavenge collector.
31//
32// VirtualSpace is data structure for committing a previously reserved address
33// range in smaller chunks.
34
35class PSVirtualSpace : public CHeapObj<mtGC> {
36  friend class VMStructs;
37 protected:
38  // The space is committed/uncommitted in chunks of size _alignment.  The
39  // ReservedSpace passed to initialize() must be aligned to this value.
40  const size_t _alignment;
41
42  // Reserved area
43  char* _reserved_low_addr;
44  char* _reserved_high_addr;
45
46  // Committed area
47  char* _committed_low_addr;
48  char* _committed_high_addr;
49
50  // The entire space has been committed and pinned in memory, no
51  // os::commit_memory() or os::uncommit_memory().
52  bool _special;
53
54  // Convenience wrapper.
55  inline static size_t pointer_delta(const char* left, const char* right);
56
57 public:
58  PSVirtualSpace(ReservedSpace rs, size_t alignment);
59  PSVirtualSpace(ReservedSpace rs);
60
61  ~PSVirtualSpace();
62
63  // Eventually all instances should be created with the above 1- or 2-arg
64  // constructors.  Then the 1st constructor below should become protected and
65  // the 2nd ctor and initialize() removed.
66  PSVirtualSpace(size_t alignment): _alignment(alignment) { }
67  PSVirtualSpace();
68  bool initialize(ReservedSpace rs, size_t commit_size);
69
70  bool contains(void* p)      const;
71
72  // Accessors (all sizes are bytes).
73  size_t alignment()          const { return _alignment; }
74  char* reserved_low_addr()   const { return _reserved_low_addr; }
75  char* reserved_high_addr()  const { return _reserved_high_addr; }
76  char* committed_low_addr()  const { return _committed_low_addr; }
77  char* committed_high_addr() const { return _committed_high_addr; }
78  bool  special()             const { return _special; }
79
80  inline size_t committed_size()   const;
81  inline size_t reserved_size()    const;
82  inline size_t uncommitted_size() const;
83
84  // Operations.
85  inline  void   set_reserved(char* low_addr, char* high_addr, bool special);
86  inline  void   set_reserved(ReservedSpace rs);
87  inline  void   set_committed(char* low_addr, char* high_addr);
88  virtual bool   expand_by(size_t bytes);
89  virtual bool   shrink_by(size_t bytes);
90  virtual size_t expand_into(PSVirtualSpace* space, size_t bytes);
91  void           release();
92
93#ifndef PRODUCT
94  // Debugging
95  static  bool is_aligned(size_t val, size_t align);
96          bool is_aligned(size_t val) const;
97          bool is_aligned(char* val) const;
98          void verify() const;
99          void print() const;
100  virtual bool grows_up() const   { return true; }
101          bool grows_down() const { return !grows_up(); }
102
103  // Helper class to verify a space when entering/leaving a block.
104  class PSVirtualSpaceVerifier: public StackObj {
105   private:
106    const PSVirtualSpace* const _space;
107   public:
108    PSVirtualSpaceVerifier(PSVirtualSpace* space): _space(space) {
109      _space->verify();
110    }
111    ~PSVirtualSpaceVerifier() { _space->verify(); }
112  };
113#endif
114
115  virtual void print_space_boundaries_on(outputStream* st) const;
116
117 // Included for compatibility with the original VirtualSpace.
118 public:
119  // Committed area
120  char* low()  const { return committed_low_addr(); }
121  char* high() const { return committed_high_addr(); }
122
123  // Reserved area
124  char* low_boundary()  const { return reserved_low_addr(); }
125  char* high_boundary() const { return reserved_high_addr(); }
126};
127
128// A virtual space that grows from high addresses to low addresses.
129class PSVirtualSpaceHighToLow : public PSVirtualSpace {
130  friend class VMStructs;
131 public:
132  PSVirtualSpaceHighToLow(ReservedSpace rs, size_t alignment);
133  PSVirtualSpaceHighToLow(ReservedSpace rs);
134
135  virtual bool   expand_by(size_t bytes);
136  virtual bool   shrink_by(size_t bytes);
137  virtual size_t expand_into(PSVirtualSpace* space, size_t bytes);
138
139  virtual void print_space_boundaries_on(outputStream* st) const;
140
141#ifndef PRODUCT
142  // Debugging
143  virtual bool grows_up() const   { return false; }
144#endif
145};
146
147//
148// PSVirtualSpace inlines.
149//
150inline size_t
151PSVirtualSpace::pointer_delta(const char* left, const char* right) {
152  return ::pointer_delta((void *)left, (void*)right, sizeof(char));
153}
154
155inline size_t PSVirtualSpace::committed_size() const {
156  return pointer_delta(committed_high_addr(), committed_low_addr());
157}
158
159inline size_t PSVirtualSpace::reserved_size() const {
160  return pointer_delta(reserved_high_addr(), reserved_low_addr());
161}
162
163inline size_t PSVirtualSpace::uncommitted_size() const {
164  return reserved_size() - committed_size();
165}
166
167inline void PSVirtualSpace::set_reserved(char* low_addr, char* high_addr, bool special) {
168  _reserved_low_addr = low_addr;
169  _reserved_high_addr = high_addr;
170  _special = special;
171}
172
173inline void PSVirtualSpace::set_reserved(ReservedSpace rs) {
174  set_reserved(rs.base(), rs.base() + rs.size(), rs.special());
175}
176
177inline void PSVirtualSpace::set_committed(char* low_addr, char* high_addr) {
178  _committed_low_addr = low_addr;
179  _committed_high_addr = high_addr;
180}
181
182#endif // SHARE_VM_GC_PARALLEL_PSVIRTUALSPACE_HPP
183