g1SATBCardTableModRefBS.hpp revision 9111:a41fe5ffa839 
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24
25#ifndef SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP
26#define SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP
27
28#include "gc/g1/g1RegionToSpaceMapper.hpp"
29#include "gc/shared/cardTableModRefBS.hpp"
30#include "memory/memRegion.hpp"
31#include "oops/oop.hpp"
32#include "utilities/macros.hpp"
33
34class DirtyCardQueueSet;
35class G1SATBCardTableLoggingModRefBS;
36
37// This barrier is specialized to use a logging barrier to support
38// snapshot-at-the-beginning marking.
39
40class G1SATBCardTableModRefBS: public CardTableModRefBS {
41  friend class VMStructs;
42protected:
43  enum G1CardValues {
44    g1_young_gen = CT_MR_BS_last_reserved << 1
45  };
46
47  G1SATBCardTableModRefBS(MemRegion whole_heap, const BarrierSet::FakeRtti& fake_rtti);
48  ~G1SATBCardTableModRefBS() { }
49
50public:
51  static int g1_young_card_val()   { return g1_young_gen; }
52
53  // Add "pre_val" to a set of objects that may have been disconnected from the
54  // pre-marking object graph.
55  static void enqueue(oop pre_val);
56
57  virtual bool has_write_ref_pre_barrier() { return true; }
58
59  // This notes that we don't need to access any BarrierSet data
60  // structures, so this can be called from a static context.
61  template <class T> static void write_ref_field_pre_static(T* field, oop newVal) {
62    T heap_oop = oopDesc::load_heap_oop(field);
63    if (!oopDesc::is_null(heap_oop)) {
64      enqueue(oopDesc::decode_heap_oop(heap_oop));
65    }
66  }
67
68  // We export this to make it available in cases where the static
69  // type of the barrier set is known.  Note that it is non-virtual.
70  template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) {
71    write_ref_field_pre_static(field, newVal);
72  }
73
74  // These are the more general virtual versions.
75  virtual void write_ref_field_pre_work(oop* field, oop new_val) {
76    inline_write_ref_field_pre(field, new_val);
77  }
78  virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) {
79    inline_write_ref_field_pre(field, new_val);
80  }
81  virtual void write_ref_field_pre_work(void* field, oop new_val) {
82    guarantee(false, "Not needed");
83  }
84
85  template <class T> void write_ref_array_pre_work(T* dst, int count);
86  virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized);
87  virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized);
88
89/*
90   Claimed and deferred bits are used together in G1 during the evacuation
91   pause. These bits can have the following state transitions:
92   1. The claimed bit can be put over any other card state. Except that
93      the "dirty -> dirty and claimed" transition is checked for in
94      G1 code and is not used.
95   2. Deferred bit can be set only if the previous state of the card
96      was either clean or claimed. mark_card_deferred() is wait-free.
97      We do not care if the operation is be successful because if
98      it does not it will only result in duplicate entry in the update
99      buffer because of the "cache-miss". So it's not worth spinning.
100 */
101
102  bool is_card_claimed(size_t card_index) {
103    jbyte val = _byte_map[card_index];
104    return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val();
105  }
106
107  void set_card_claimed(size_t card_index) {
108      jbyte val = _byte_map[card_index];
109      if (val == clean_card_val()) {
110        val = (jbyte)claimed_card_val();
111      } else {
112        val |= (jbyte)claimed_card_val();
113      }
114      _byte_map[card_index] = val;
115  }
116
117  void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN;
118  void g1_mark_as_young(const MemRegion& mr);
119
120  bool mark_card_deferred(size_t card_index);
121
122  bool is_card_deferred(size_t card_index) {
123    jbyte val = _byte_map[card_index];
124    return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val();
125  }
126  virtual void write_ref_nmethod_pre(oop* dst, nmethod* nm);
127  virtual void write_ref_nmethod_post(oop* dst, nmethod* nm);
128
129};
130
131template<>
132struct BarrierSet::GetName<G1SATBCardTableModRefBS> {
133  static const BarrierSet::Name value = BarrierSet::G1SATBCT;
134};
135
136class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener {
137 private:
138  G1SATBCardTableLoggingModRefBS* _card_table;
139 public:
140  G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { }
141
142  void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; }
143
144  virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled);
145};
146
147// Adds card-table logging to the post-barrier.
148// Usual invariant: all dirty cards are logged in the DirtyCardQueueSet.
149class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS {
150  friend class G1SATBCardTableLoggingModRefBSChangedListener;
151 private:
152  G1SATBCardTableLoggingModRefBSChangedListener _listener;
153  DirtyCardQueueSet& _dcqs;
154
155 protected:
156  virtual void write_ref_field_work(void* field, oop new_val, bool release);
157
158 public:
159  static size_t compute_size(size_t mem_region_size_in_words) {
160    size_t number_of_slots = (mem_region_size_in_words / card_size_in_words);
161    return ReservedSpace::allocation_align_size_up(number_of_slots);
162  }
163
164  // Returns how many bytes of the heap a single byte of the Card Table corresponds to.
165  static size_t heap_map_factor() {
166    return CardTableModRefBS::card_size;
167  }
168
169  G1SATBCardTableLoggingModRefBS(MemRegion whole_heap);
170
171  virtual void initialize() { }
172  virtual void initialize(G1RegionToSpaceMapper* mapper);
173
174  virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); }
175
176  // Can be called from static contexts.
177  static void write_ref_field_static(void* field, oop new_val);
178
179  // NB: if you do a whole-heap invalidation, the "usual invariant" defined
180  // above no longer applies.
181  void invalidate(MemRegion mr, bool whole_heap = false);
182
183  void write_region_work(MemRegion mr)    { invalidate(mr); }
184  void write_ref_array_work(MemRegion mr) { invalidate(mr); }
185};
186
187template<>
188struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> {
189  static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging;
190};
191
192#endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP
193