1 /* 2 * Copyright (c) 2013, 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_G1CARDCOUNTS_HPP 26 #define SHARE_VM_GC_G1_G1CARDCOUNTS_HPP 27 28 #include "gc/g1/g1CardTable.hpp" 29 #include "gc/g1/g1RegionToSpaceMapper.hpp" 30 #include "memory/allocation.hpp" 31 #include "memory/virtualspace.hpp" 32 #include "utilities/globalDefinitions.hpp" 33 34 class CardTableModRefBS; 35 class G1CardCounts; 36 class G1CollectedHeap; 37 class G1RegionToSpaceMapper; 38 class HeapRegion; 39 40 class G1CardCountsMappingChangedListener : public G1MappingChangedListener { 41 private: 42 G1CardCounts* _counts; 43 public: 44 void set_cardcounts(G1CardCounts* counts) { _counts = counts; } 45 46 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 47 }; 48 49 // Table to track the number of times a card has been refined. Once 50 // a card has been refined a certain number of times, it is 51 // considered 'hot' and its refinement is delayed by inserting the 52 // card into the hot card cache. The card will then be refined when 53 // it is evicted from the hot card cache, or when the hot card cache 54 // is 'drained' during the next evacuation pause. 55 56 class G1CardCounts: public CHeapObj<mtGC> { 57 G1CardCountsMappingChangedListener _listener; 58 59 G1CollectedHeap* _g1h; 60 61 // The table of counts 62 jubyte* _card_counts; 63 64 // Max capacity of the reserved space for the counts table 65 size_t _reserved_max_card_num; 66 67 // CardTable bottom. 68 const jbyte* _ct_bot; 69 70 // Barrier set 71 G1CardTable* _ct; 72 73 // Returns true if the card counts table has been reserved. 74 bool has_reserved_count_table() { return _card_counts != NULL; } 75 76 // Returns true if the card counts table has been reserved and committed. 77 bool has_count_table() { 78 return has_reserved_count_table(); 79 } 80 81 size_t ptr_2_card_num(const jbyte* card_ptr) { 82 assert(card_ptr >= _ct_bot, 83 "Invalid card pointer: " 84 "card_ptr: " PTR_FORMAT ", " 85 "_ct_bot: " PTR_FORMAT, 86 p2i(card_ptr), p2i(_ct_bot)); 87 size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte)); 88 assert(card_num < _reserved_max_card_num, 89 "card pointer out of range: " PTR_FORMAT, p2i(card_ptr)); 90 return card_num; 91 } 92 93 jbyte* card_num_2_ptr(size_t card_num) { 94 assert(card_num < _reserved_max_card_num, 95 "card num out of range: " SIZE_FORMAT, card_num); 96 return (jbyte*) (_ct_bot + card_num); 97 } 98 99 // Clear the counts table for the given (exclusive) index range. 100 void clear_range(size_t from_card_num, size_t to_card_num); 101 102 public: 103 G1CardCounts(G1CollectedHeap* g1h); 104 105 // Return the number of slots needed for a card counts table 106 // that covers mem_region_words words. 107 static size_t compute_size(size_t mem_region_size_in_words); 108 109 // Returns how many bytes of the heap a single byte of the card counts table 110 // corresponds to. 111 static size_t heap_map_factor(); 112 113 void initialize(G1RegionToSpaceMapper* mapper); 114 115 // Increments the refinement count for the given card. 116 // Returns the pre-increment count value. 117 uint add_card_count(jbyte* card_ptr); 118 119 // Returns true if the given count is high enough to be considered 120 // 'hot'; false otherwise. 121 bool is_hot(uint count); 122 123 // Clears the card counts for the cards spanned by the region 124 void clear_region(HeapRegion* hr); 125 126 // Clears the card counts for the cards spanned by the MemRegion 127 void clear_range(MemRegion mr); 128 129 // Clear the entire card counts table during GC. 130 void clear_all(); 131 }; 132 133 #endif // SHARE_VM_GC_G1_G1CARDCOUNTS_HPP