remembered_set.cc revision 507dfdd147c97bfbadebfd63584d094b6a4e7b47 
1/*
2 * Copyright (C) 2014 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "remembered_set.h"
18
19#include "base/stl_util.h"
20#include "card_table-inl.h"
21#include "heap_bitmap.h"
22#include "gc/collector/mark_sweep.h"
23#include "gc/collector/mark_sweep-inl.h"
24#include "gc/collector/semi_space.h"
25#include "gc/heap.h"
26#include "gc/space/space.h"
27#include "mirror/art_field-inl.h"
28#include "mirror/object-inl.h"
29#include "mirror/class-inl.h"
30#include "mirror/object_array-inl.h"
31#include "space_bitmap-inl.h"
32#include "thread.h"
33#include "UniquePtrCompat.h"
34
35namespace art {
36namespace gc {
37namespace accounting {
38
39class RememberedSetCardVisitor {
40 public:
41  explicit RememberedSetCardVisitor(RememberedSet::CardSet* const dirty_cards)
42      : dirty_cards_(dirty_cards) {}
43
44  void operator()(byte* card, byte expected_value, byte new_value) const {
45    if (expected_value == CardTable::kCardDirty) {
46      dirty_cards_->insert(card);
47    }
48  }
49
50 private:
51  RememberedSet::CardSet* const dirty_cards_;
52};
53
54void RememberedSet::ClearCards() {
55  CardTable* card_table = GetHeap()->GetCardTable();
56  RememberedSetCardVisitor card_visitor(&dirty_cards_);
57  // Clear dirty cards in the space and insert them into the dirty card set.
58  card_table->ModifyCardsAtomic(space_->Begin(), space_->End(), AgeCardVisitor(), card_visitor);
59}
60
61class RememberedSetReferenceVisitor {
62 public:
63  RememberedSetReferenceVisitor(MarkHeapReferenceCallback* callback,
64                                DelayReferenceReferentCallback* ref_callback,
65                                space::ContinuousSpace* target_space,
66                                bool* const contains_reference_to_target_space, void* arg)
67      : callback_(callback), ref_callback_(ref_callback), target_space_(target_space), arg_(arg),
68        contains_reference_to_target_space_(contains_reference_to_target_space) {}
69
70  void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const
71      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
72    DCHECK(obj != nullptr);
73    mirror::HeapReference<mirror::Object>* ref_ptr = obj->GetFieldObjectReferenceAddr(offset);
74    if (target_space_->HasAddress(ref_ptr->AsMirrorPtr())) {
75      *contains_reference_to_target_space_ = true;
76      callback_(ref_ptr, arg_);
77      DCHECK(!target_space_->HasAddress(ref_ptr->AsMirrorPtr()));
78    }
79  }
80
81  void operator()(mirror::Class* klass, mirror::Reference* ref) const
82      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_)
83      EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_) {
84    if (target_space_->HasAddress(ref->GetReferent())) {
85      *contains_reference_to_target_space_ = true;
86      ref_callback_(klass, ref, arg_);
87    }
88  }
89
90 private:
91  MarkHeapReferenceCallback* const callback_;
92  DelayReferenceReferentCallback* const ref_callback_;
93  space::ContinuousSpace* const target_space_;
94  void* const arg_;
95  bool* const contains_reference_to_target_space_;
96};
97
98class RememberedSetObjectVisitor {
99 public:
100  RememberedSetObjectVisitor(MarkHeapReferenceCallback* callback,
101                             DelayReferenceReferentCallback* ref_callback,
102                             space::ContinuousSpace* target_space,
103                             bool* const contains_reference_to_target_space, void* arg)
104      : callback_(callback), ref_callback_(ref_callback), target_space_(target_space), arg_(arg),
105        contains_reference_to_target_space_(contains_reference_to_target_space) {}
106
107  void operator()(mirror::Object* obj) const EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
108      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
109    RememberedSetReferenceVisitor visitor(callback_, ref_callback_, target_space_,
110                                          contains_reference_to_target_space_, arg_);
111    obj->VisitReferences<kMovingClasses>(visitor, visitor);
112  }
113
114 private:
115  MarkHeapReferenceCallback* const callback_;
116  DelayReferenceReferentCallback* const ref_callback_;
117  space::ContinuousSpace* const target_space_;
118  void* const arg_;
119  bool* const contains_reference_to_target_space_;
120};
121
122void RememberedSet::UpdateAndMarkReferences(MarkHeapReferenceCallback* callback,
123                                            DelayReferenceReferentCallback* ref_callback,
124                                            space::ContinuousSpace* target_space, void* arg) {
125  CardTable* card_table = heap_->GetCardTable();
126  bool contains_reference_to_target_space = false;
127  RememberedSetObjectVisitor obj_visitor(callback, ref_callback, target_space,
128                                         &contains_reference_to_target_space, arg);
129  ContinuousSpaceBitmap* bitmap = space_->GetLiveBitmap();
130  CardSet remove_card_set;
131  for (byte* const card_addr : dirty_cards_) {
132    contains_reference_to_target_space = false;
133    uintptr_t start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr));
134    DCHECK(space_->HasAddress(reinterpret_cast<mirror::Object*>(start)));
135    bitmap->VisitMarkedRange(start, start + CardTable::kCardSize, obj_visitor);
136    if (!contains_reference_to_target_space) {
137      // It was in the dirty card set, but it didn't actually contain
138      // a reference to the target space. So, remove it from the dirty
139      // card set so we won't have to scan it again (unless it gets
140      // dirty again.)
141      remove_card_set.insert(card_addr);
142    }
143  }
144
145  // Remove the cards that didn't contain a reference to the target
146  // space from the dirty card set.
147  for (byte* const card_addr : remove_card_set) {
148    DCHECK(dirty_cards_.find(card_addr) != dirty_cards_.end());
149    dirty_cards_.erase(card_addr);
150  }
151}
152
153void RememberedSet::Dump(std::ostream& os) {
154  CardTable* card_table = heap_->GetCardTable();
155  os << "RememberedSet dirty cards: [";
156  for (const byte* card_addr : dirty_cards_) {
157    auto start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr));
158    auto end = start + CardTable::kCardSize;
159    os << reinterpret_cast<void*>(start) << "-" << reinterpret_cast<void*>(end) << "\n";
160  }
161  os << "]";
162}
163
164void RememberedSet::AssertAllDirtyCardsAreWithinSpace() const {
165  CardTable* card_table = heap_->GetCardTable();
166  for (const byte* card_addr : dirty_cards_) {
167    auto start = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr));
168    auto end = start + CardTable::kCardSize;
169    DCHECK_LE(space_->Begin(), start);
170    DCHECK_LE(end, space_->Limit());
171  }
172}
173
174}  // namespace accounting
175}  // namespace gc
176}  // namespace art
177