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