1 /* 2 * Copyright (c) 2001, 2018, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 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 34 class DirtyCardQueueSet; 35 class G1SATBCardTableLoggingModRefBS; 36 37 // This barrier is specialized to use a logging barrier to support 38 // snapshot-at-the-beginning marking. 39 40 class G1SATBCardTableModRefBS: public CardTableModRefBS { 41 friend class VMStructs; 42 protected: 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 50 public: 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 static void enqueue_if_weak_or_archive(DecoratorSet decorators, oop value); 58 59 template <class T> void write_ref_array_pre_work(T* dst, int count); 60 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized); 61 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized); 62 63 template <DecoratorSet decorators, typename T> 64 void write_ref_field_pre(T* field); 65 66 /* 67 Claimed and deferred bits are used together in G1 during the evacuation 68 pause. These bits can have the following state transitions: 69 1. The claimed bit can be put over any other card state. Except that 70 the "dirty -> dirty and claimed" transition is checked for in 71 G1 code and is not used. 72 2. Deferred bit can be set only if the previous state of the card 73 was either clean or claimed. mark_card_deferred() is wait-free. 74 We do not care if the operation is be successful because if 75 it does not it will only result in duplicate entry in the update 76 buffer because of the "cache-miss". So it's not worth spinning. 77 */ 78 79 bool is_card_claimed(size_t card_index) { 80 jbyte val = _byte_map[card_index]; 81 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val(); 82 } 83 84 inline void set_card_claimed(size_t card_index); 85 86 void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN; 87 void g1_mark_as_young(const MemRegion& mr); 88 89 bool mark_card_deferred(size_t card_index); 90 91 bool is_card_deferred(size_t card_index) { 92 jbyte val = _byte_map[card_index]; 93 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val(); 94 } 95 96 virtual bool is_in_young(oop obj) const; 97 }; 98 99 template<> 100 struct BarrierSet::GetName<G1SATBCardTableModRefBS> { 101 static const BarrierSet::Name value = BarrierSet::G1SATBCT; 102 }; 103 104 template<> 105 struct BarrierSet::GetType<BarrierSet::G1SATBCT> { 106 typedef G1SATBCardTableModRefBS type; 107 }; 108 109 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener { 110 private: 111 G1SATBCardTableLoggingModRefBS* _card_table; 112 public: 113 G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { } 114 115 void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; } 116 117 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 118 }; 119 120 // Adds card-table logging to the post-barrier. 121 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet. 122 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS { 123 friend class G1SATBCardTableLoggingModRefBSChangedListener; 124 private: 125 G1SATBCardTableLoggingModRefBSChangedListener _listener; 126 DirtyCardQueueSet& _dcqs; 127 128 public: 129 static size_t compute_size(size_t mem_region_size_in_words) { 130 size_t number_of_slots = (mem_region_size_in_words / card_size_in_words); 131 return ReservedSpace::allocation_align_size_up(number_of_slots); 132 } 133 134 // Returns how many bytes of the heap a single byte of the Card Table corresponds to. 135 static size_t heap_map_factor() { 136 return CardTableModRefBS::card_size; 137 } 138 139 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap); 140 141 virtual void initialize() { } 142 virtual void initialize(G1RegionToSpaceMapper* mapper); 143 144 virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); } 145 146 // NB: if you do a whole-heap invalidation, the "usual invariant" defined 147 // above no longer applies. 148 void invalidate(MemRegion mr); 149 150 void write_region(MemRegion mr) { invalidate(mr); } 151 void write_ref_array_work(MemRegion mr) { invalidate(mr); } 152 153 template <DecoratorSet decorators, typename T> 154 void write_ref_field_post(T* field, oop new_val); 155 void write_ref_field_post_slow(volatile jbyte* byte); 156 157 virtual void on_thread_attach(JavaThread* thread); 158 virtual void on_thread_detach(JavaThread* thread); 159 160 virtual bool card_mark_must_follow_store() const { 161 return true; 162 } 163 164 // Callbacks for runtime accesses. 165 template <DecoratorSet decorators, typename BarrierSetT = G1SATBCardTableLoggingModRefBS> 166 class AccessBarrier: public ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> { 167 typedef ModRefBarrierSet::AccessBarrier<decorators, BarrierSetT> ModRef; 168 typedef BarrierSet::AccessBarrier<decorators, BarrierSetT> Raw; 169 170 public: 171 // Needed for loads on non-heap weak references 172 template <typename T> 173 static oop oop_load_not_in_heap(T* addr); 174 175 // Needed for non-heap stores 176 template <typename T> 177 static void oop_store_not_in_heap(T* addr, oop new_value); 178 179 // Needed for weak references 180 static oop oop_load_in_heap_at(oop base, ptrdiff_t offset); 181 182 // Defensive: will catch weak oops at addresses in heap 183 template <typename T> 184 static oop oop_load_in_heap(T* addr); 185 }; 186 }; 187 188 template<> 189 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> { 190 static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging; 191 }; 192 193 template<> 194 struct BarrierSet::GetType<BarrierSet::G1SATBCTLogging> { 195 typedef G1SATBCardTableLoggingModRefBS type; 196 }; 197 198 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP