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_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP 27 28 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp" 29 #include "memory/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, BarrierSet::Name kind); 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 bool is_a(BarrierSet::Name bsn) { 57 return bsn == BarrierSet::G1SATBCT || CardTableModRefBS::is_a(bsn); 58 } 59 60 virtual bool has_write_ref_pre_barrier() { return true; } 61 62 // This notes that we don't need to access any BarrierSet data 63 // structures, so this can be called from a static context. 64 template <class T> static void write_ref_field_pre_static(T* field, oop newVal) { 65 T heap_oop = oopDesc::load_heap_oop(field); 66 if (!oopDesc::is_null(heap_oop)) { 67 enqueue(oopDesc::decode_heap_oop(heap_oop)); 68 } 69 } 70 71 // We export this to make it available in cases where the static 72 // type of the barrier set is known. Note that it is non-virtual. 73 template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) { 74 write_ref_field_pre_static(field, newVal); 75 } 76 77 // These are the more general virtual versions. 78 virtual void write_ref_field_pre_work(oop* field, oop new_val) { 79 inline_write_ref_field_pre(field, new_val); 80 } 81 virtual void write_ref_field_pre_work(narrowOop* field, oop new_val) { 82 inline_write_ref_field_pre(field, new_val); 83 } 84 virtual void write_ref_field_pre_work(void* field, oop new_val) { 85 guarantee(false, "Not needed"); 86 } 87 88 template <class T> void write_ref_array_pre_work(T* dst, int count); 89 virtual void write_ref_array_pre(oop* dst, int count, bool dest_uninitialized); 90 virtual void write_ref_array_pre(narrowOop* dst, int count, bool dest_uninitialized); 91 92 /* 93 Claimed and deferred bits are used together in G1 during the evacuation 94 pause. These bits can have the following state transitions: 95 1. The claimed bit can be put over any other card state. Except that 96 the "dirty -> dirty and claimed" transition is checked for in 97 G1 code and is not used. 98 2. Deferred bit can be set only if the previous state of the card 99 was either clean or claimed. mark_card_deferred() is wait-free. 100 We do not care if the operation is be successful because if 101 it does not it will only result in duplicate entry in the update 102 buffer because of the "cache-miss". So it's not worth spinning. 103 */ 104 105 bool is_card_claimed(size_t card_index) { 106 jbyte val = _byte_map[card_index]; 107 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val(); 108 } 109 110 void set_card_claimed(size_t card_index) { 111 jbyte val = _byte_map[card_index]; 112 if (val == clean_card_val()) { 113 val = (jbyte)claimed_card_val(); 114 } else { 115 val |= (jbyte)claimed_card_val(); 116 } 117 _byte_map[card_index] = val; 118 } 119 120 void verify_g1_young_region(MemRegion mr) PRODUCT_RETURN; 121 void g1_mark_as_young(const MemRegion& mr); 122 123 bool mark_card_deferred(size_t card_index); 124 125 bool is_card_deferred(size_t card_index) { 126 jbyte val = _byte_map[card_index]; 127 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val(); 128 } 129 }; 130 131 class G1SATBCardTableLoggingModRefBSChangedListener : public G1MappingChangedListener { 132 private: 133 G1SATBCardTableLoggingModRefBS* _card_table; 134 public: 135 G1SATBCardTableLoggingModRefBSChangedListener() : _card_table(NULL) { } 136 137 void set_card_table(G1SATBCardTableLoggingModRefBS* card_table) { _card_table = card_table; } 138 139 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 140 }; 141 142 // Adds card-table logging to the post-barrier. 143 // Usual invariant: all dirty cards are logged in the DirtyCardQueueSet. 144 class G1SATBCardTableLoggingModRefBS: public G1SATBCardTableModRefBS { 145 friend class G1SATBCardTableLoggingModRefBSChangedListener; 146 private: 147 G1SATBCardTableLoggingModRefBSChangedListener _listener; 148 DirtyCardQueueSet& _dcqs; 149 public: 150 static size_t compute_size(size_t mem_region_size_in_words) { 151 size_t number_of_slots = (mem_region_size_in_words / card_size_in_words); 152 return ReservedSpace::allocation_align_size_up(number_of_slots); 153 } 154 155 G1SATBCardTableLoggingModRefBS(MemRegion whole_heap); 156 157 virtual void initialize() { } 158 virtual void initialize(G1RegionToSpaceMapper* mapper); 159 160 virtual void resize_covered_region(MemRegion new_region) { ShouldNotReachHere(); } 161 162 bool is_a(BarrierSet::Name bsn) { 163 return bsn == BarrierSet::G1SATBCTLogging || 164 G1SATBCardTableModRefBS::is_a(bsn); 165 } 166 167 void write_ref_field_work(void* field, oop new_val, bool release = false); 168 169 // Can be called from static contexts. 170 static void write_ref_field_static(void* field, oop new_val); 171 172 // NB: if you do a whole-heap invalidation, the "usual invariant" defined 173 // above no longer applies. 174 void invalidate(MemRegion mr, bool whole_heap = false); 175 176 void write_region_work(MemRegion mr) { invalidate(mr); } 177 void write_ref_array_work(MemRegion mr) { invalidate(mr); } 178 }; 179 180 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1SATBCARDTABLEMODREFBS_HPP