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 <memory> 20 21#include "base/stl_util.h" 22#include "card_table-inl.h" 23#include "heap_bitmap.h" 24#include "gc/collector/mark_sweep.h" 25#include "gc/collector/mark_sweep-inl.h" 26#include "gc/collector/semi_space.h" 27#include "gc/heap.h" 28#include "gc/space/space.h" 29#include "mirror/object-inl.h" 30#include "mirror/class-inl.h" 31#include "mirror/object_array-inl.h" 32#include "space_bitmap-inl.h" 33#include "thread.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()(uint8_t* card, uint8_t expected_value, uint8_t new_value ATTRIBUTE_UNUSED) 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(space::ContinuousSpace* target_space, 64 bool* const contains_reference_to_target_space, 65 collector::GarbageCollector* collector) 66 : collector_(collector), target_space_(target_space), 67 contains_reference_to_target_space_(contains_reference_to_target_space) {} 68 69 void operator()(mirror::Object* obj, MemberOffset offset, bool is_static ATTRIBUTE_UNUSED) const 70 SHARED_REQUIRES(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 collector_->MarkHeapReference(ref_ptr); 76 DCHECK(!target_space_->HasAddress(ref_ptr->AsMirrorPtr())); 77 } 78 } 79 80 void operator()(mirror::Class* klass, mirror::Reference* ref) const 81 SHARED_REQUIRES(Locks::mutator_lock_) REQUIRES(Locks::heap_bitmap_lock_) { 82 if (target_space_->HasAddress(ref->GetReferent())) { 83 *contains_reference_to_target_space_ = true; 84 collector_->DelayReferenceReferent(klass, ref); 85 } 86 } 87 88 void VisitRootIfNonNull(mirror::CompressedReference<mirror::Object>* root) const 89 SHARED_REQUIRES(Locks::mutator_lock_) { 90 if (!root->IsNull()) { 91 VisitRoot(root); 92 } 93 } 94 95 void VisitRoot(mirror::CompressedReference<mirror::Object>* root) const 96 SHARED_REQUIRES(Locks::mutator_lock_) { 97 if (target_space_->HasAddress(root->AsMirrorPtr())) { 98 *contains_reference_to_target_space_ = true; 99 root->Assign(collector_->MarkObject(root->AsMirrorPtr())); 100 DCHECK(!target_space_->HasAddress(root->AsMirrorPtr())); 101 } 102 } 103 104 private: 105 collector::GarbageCollector* const collector_; 106 space::ContinuousSpace* const target_space_; 107 bool* const contains_reference_to_target_space_; 108}; 109 110class RememberedSetObjectVisitor { 111 public: 112 RememberedSetObjectVisitor(space::ContinuousSpace* target_space, 113 bool* const contains_reference_to_target_space, 114 collector::GarbageCollector* collector) 115 : collector_(collector), target_space_(target_space), 116 contains_reference_to_target_space_(contains_reference_to_target_space) {} 117 118 void operator()(mirror::Object* obj) const REQUIRES(Locks::heap_bitmap_lock_) 119 SHARED_REQUIRES(Locks::mutator_lock_) { 120 RememberedSetReferenceVisitor visitor(target_space_, contains_reference_to_target_space_, 121 collector_); 122 obj->VisitReferences(visitor, visitor); 123 } 124 125 private: 126 collector::GarbageCollector* const collector_; 127 space::ContinuousSpace* const target_space_; 128 bool* const contains_reference_to_target_space_; 129}; 130 131void RememberedSet::UpdateAndMarkReferences(space::ContinuousSpace* target_space, 132 collector::GarbageCollector* collector) { 133 CardTable* card_table = heap_->GetCardTable(); 134 bool contains_reference_to_target_space = false; 135 RememberedSetObjectVisitor obj_visitor(target_space, &contains_reference_to_target_space, 136 collector); 137 ContinuousSpaceBitmap* bitmap = space_->GetLiveBitmap(); 138 CardSet remove_card_set; 139 for (uint8_t* const card_addr : dirty_cards_) { 140 contains_reference_to_target_space = false; 141 uintptr_t start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr)); 142 DCHECK(space_->HasAddress(reinterpret_cast<mirror::Object*>(start))); 143 bitmap->VisitMarkedRange(start, start + CardTable::kCardSize, obj_visitor); 144 if (!contains_reference_to_target_space) { 145 // It was in the dirty card set, but it didn't actually contain 146 // a reference to the target space. So, remove it from the dirty 147 // card set so we won't have to scan it again (unless it gets 148 // dirty again.) 149 remove_card_set.insert(card_addr); 150 } 151 } 152 153 // Remove the cards that didn't contain a reference to the target 154 // space from the dirty card set. 155 for (uint8_t* const card_addr : remove_card_set) { 156 DCHECK(dirty_cards_.find(card_addr) != dirty_cards_.end()); 157 dirty_cards_.erase(card_addr); 158 } 159} 160 161void RememberedSet::Dump(std::ostream& os) { 162 CardTable* card_table = heap_->GetCardTable(); 163 os << "RememberedSet dirty cards: ["; 164 for (const uint8_t* card_addr : dirty_cards_) { 165 auto start = reinterpret_cast<uintptr_t>(card_table->AddrFromCard(card_addr)); 166 auto end = start + CardTable::kCardSize; 167 os << reinterpret_cast<void*>(start) << "-" << reinterpret_cast<void*>(end) << "\n"; 168 } 169 os << "]"; 170} 171 172void RememberedSet::AssertAllDirtyCardsAreWithinSpace() const { 173 CardTable* card_table = heap_->GetCardTable(); 174 for (const uint8_t* card_addr : dirty_cards_) { 175 auto start = reinterpret_cast<uint8_t*>(card_table->AddrFromCard(card_addr)); 176 auto end = start + CardTable::kCardSize; 177 DCHECK_LE(space_->Begin(), start); 178 DCHECK_LE(end, space_->Limit()); 179 } 180} 181 182} // namespace accounting 183} // namespace gc 184} // namespace art 185