remembered_set.cc revision a8e8f9c0a8e259a807d7b99a148d14104c24209d 
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 "UniquePtr.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                                space::ContinuousSpace* target_space,
65                                bool* const contains_reference_to_target_space, void* arg)
66      : callback_(callback), target_space_(target_space), arg_(arg),
67        contains_reference_to_target_space_(contains_reference_to_target_space) {}
68
69  void operator()(mirror::Object* obj, MemberOffset offset, bool /* is_static */) const
70      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
71    DCHECK(obj != nullptr);
72    mirror::HeapReference<mirror::Object>* ref_ptr = obj->GetFieldObjectReferenceAddr(offset);
73    if (target_space_->HasAddress(ref_ptr->AsMirrorPtr())) {
74      *contains_reference_to_target_space_ = true;
75      callback_(ref_ptr, arg_);
76      DCHECK(!target_space_->HasAddress(ref_ptr->AsMirrorPtr()));
77    }
78  }
79
80 private:
81  MarkHeapReferenceCallback* const callback_;
82  space::ContinuousSpace* const target_space_;
83  void* const arg_;
84  bool* const contains_reference_to_target_space_;
85};
86
87class RememberedSetObjectVisitor {
88 public:
89  RememberedSetObjectVisitor(MarkHeapReferenceCallback* callback,
90                             space::ContinuousSpace* target_space,
91                             bool* const contains_reference_to_target_space, void* arg)
92      : callback_(callback), target_space_(target_space), arg_(arg),
93        contains_reference_to_target_space_(contains_reference_to_target_space) {}
94
95  void operator()(mirror::Object* obj) const EXCLUSIVE_LOCKS_REQUIRED(Locks::heap_bitmap_lock_)
96      SHARED_LOCKS_REQUIRED(Locks::mutator_lock_) {
97    RememberedSetReferenceVisitor ref_visitor(callback_, target_space_,
98                                              contains_reference_to_target_space_, arg_);
99    obj->VisitReferences<kMovingClasses>(ref_visitor);
100  }
101
102 private:
103  MarkHeapReferenceCallback* const callback_;
104  space::ContinuousSpace* const target_space_;
105  void* const arg_;
106  bool* const contains_reference_to_target_space_;
107};
108
109void RememberedSet::UpdateAndMarkReferences(MarkHeapReferenceCallback* callback,
110                                            space::ContinuousSpace* target_space, void* arg) {
111  CardTable* card_table = heap_->GetCardTable();
112  bool contains_reference_to_target_space = false;
113  RememberedSetObjectVisitor obj_visitor(callback, target_space,
114                                         &contains_reference_to_target_space, arg);
115  ContinuousSpaceBitmap* bitmap = space_->GetLiveBitmap();
116  CardSet remove_card_set;
117  for (byte* const card_addr : dirty_cards_) {
118    contains_reference_to_target_space = false;
119    uintptr_t start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr));
120    DCHECK(space_->HasAddress(reinterpret_cast<mirror::Object*>(start)));
121    bitmap->VisitMarkedRange(start, start + CardTable::kCardSize, obj_visitor);
122    if (!contains_reference_to_target_space) {
123      // It was in the dirty card set, but it didn't actually contain
124      // a reference to the target space. So, remove it from the dirty
125      // card set so we won't have to scan it again (unless it gets
126      // dirty again.)
127      remove_card_set.insert(card_addr);
128    }
129  }
130
131  // Remove the cards that didn't contain a reference to the target
132  // space from the dirty card set.
133  for (byte* const card_addr : remove_card_set) {
134    DCHECK(dirty_cards_.find(card_addr) != dirty_cards_.end());
135    dirty_cards_.erase(card_addr);
136  }
137}
138
139void RememberedSet::Dump(std::ostream& os) {
140  CardTable* card_table = heap_->GetCardTable();
141  os << "RememberedSet dirty cards: [";
142  for (const byte* card_addr : dirty_cards_) {
143    auto start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr));
144    auto end = start + CardTable::kCardSize;
145    os << reinterpret_cast<void*>(start) << "-" << reinterpret_cast<void*>(end) << "\n";
146  }
147  os << "]";
148}
149
150void RememberedSet::AssertAllDirtyCardsAreWithinSpace() const {
151  CardTable* card_table = heap_->GetCardTable();
152  for (const byte* card_addr : dirty_cards_) {
153    auto start = reinterpret_cast<byte*>(card_table->AddrFromCard(card_addr));
154    auto end = start + CardTable::kCardSize;
155    DCHECK_LE(space_->Begin(), start);
156    DCHECK_LE(end, space_->Limit());
157  }
158}
159
160}  // namespace accounting
161}  // namespace gc
162}  // namespace art
163