1 /* 2 * Copyright (c) 2001, 2015, 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 protected: 42 enum G1CardValues { 43 g1_young_gen = CT_MR_BS_last_reserved << 1 44 }; 45 46 G1SATBCardTableModRefBS(MemRegion whole_heap, const BarrierSet::FakeRtti& fake_rtti); 47 ~G1SATBCardTableModRefBS() { } 48 49 public: 50 static int g1_young_card_val() { return g1_young_gen; } 51 52 // Add "pre_val" to a set of objects that may have been disconnected from the 53 // pre-marking object graph. 54 static void enqueue(oop pre_val); 55 56 virtual bool has_write_ref_pre_barrier() { return true; } 57 58 // This notes that we don't need to access any BarrierSet data 59 // structures, so this can be called from a static context. 60 template <class T> static void write_ref_field_pre_static(T* field, oop newVal) { 61 T heap_oop = oopDesc::load_heap_oop(field); 62 if (!oopDesc::is_null(heap_oop)) { 63 enqueue(oopDesc::decode_heap_oop(heap_oop)); 64 } 65 } 66 67 // We export this to make it available in cases where the static 68 // type of the barrier set is known. Note that it is non-virtual. 69 template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) { 70 write_ref_field_pre_static(field, newVal); 71 } 72 73 // These are the more general virtual versions. 74 virtual void write_ref_field_pre_work(oop* field, oop new_val) { 75 inline_write_ref_field_pre(field, new_val); 76 } 77 virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) { 78 inline_write_ref_field_pre(field, new_val); 79 } 80 virtual void write_ref_field_pre_work(void* field, oop new_val) { 81 guarantee(false, "Not needed"); 82 } 83 84 template <class T> void write_ref_array_pre_work(T* dst, int count); 85 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized); 86 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized); 87 88 /* 89 Claimed and deferred bits are used together in G1 during the evacuation 90 pause. These bits can have the following state transitions: 91 1. The claimed bit can be put over any other card state. Except that 92 the "dirty -> dirty and claimed" transition is checked for in 93 G1 code and is not used. 94 2. Deferred bit can be set only if the previous state of the card 95 was either clean or claimed. mark_card_deferred() is wait-free. 96 We do not care if the operation is be successful because if 97 it does not it will only result in duplicate entry in the update 98 buffer because of the "cache-miss". So it's not worth spinning. 99 */ 100 101 bool is_card_claimed(size_t card_index) { 102 jbyte val = _byte_map[card_index]; 103 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val(); 104 } 105 106 void set_card_claimed(size_t card_index) { 107 jbyte val = _byte_map[card_index]; 108 if (val == clean_card_val()) { 109 val = (jbyte)claimed_card_val(); 110 } else { 111 val |= (jbyte)claimed_card_val(); 112 } 113 _byte_map[card_index] = val; 114 } 115 116 void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN; 117 void g1_mark_as_young(const MemRegion& mr); 118 119 bool mark_card_deferred(size_t card_index); 120 121 bool is_card_deferred(size_t card_index) { 122 jbyte val = _byte_map[card_index]; 123 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val(); 124 } 125 }; 126 127 template<> 128 struct BarrierSet::GetName<G1SATBCardTableModRefBS> { 129 static const BarrierSet::Name value = BarrierSet::G1SATBCT; 130 }; 131 132 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener { 133 private: 134 G1SATBCardTableLoggingModRefBS* _card_table; 135 public: 136 G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { } 137 138 void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; } 139 140 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 141 }; 142 143 // Adds card-table logging to the post-barrier. 144 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet. 145 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS { 146 friend class G1SATBCardTableLoggingModRefBSChangedListener; 147 private: 148 G1SATBCardTableLoggingModRefBSChangedListener _listener; 149 DirtyCardQueueSet& _dcqs; 150 151 protected: 152 virtual void write_ref_field_work(void* field, oop new_val, bool release); 153 154 public: 155 static size_t compute_size(size_t mem_region_size_in_words) { 156 size_t number_of_slots = (mem_region_size_in_words / card_size_in_words); 157 return ReservedSpace::allocation_align_size_up(number_of_slots); 158 } 159 160 // Returns how many bytes of the heap a single byte of the Card Table corresponds to. 161 static size_t heap_map_factor() { 162 return CardTableModRefBS::card_size; 163 } 164 165 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap); 166 167 virtual void initialize() { } 168 virtual void initialize(G1RegionToSpaceMapper* mapper); 169 170 virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); } 171 172 // Can be called from static contexts. 173 static void write_ref_field_static(void* field, oop new_val); 174 175 // NB: if you do a whole-heap invalidation, the "usual invariant" defined 176 // above no longer applies. 177 void invalidate(MemRegion mr, bool whole_heap = false); 178 179 void write_region_work(MemRegion mr) { invalidate(mr); } 180 void write_ref_array_work(MemRegion mr) { invalidate(mr); } 181 }; 182 183 template<> 184 struct BarrierSet::GetName<G1SATBCardTableLoggingModRefBS> { 185 static const BarrierSet::Name value = BarrierSet::G1SATBCTLogging; 186 }; 187 188 #endif // SHARE_VM_GC_G1_G1SATBCARDTABLEMODREFBS_HPP