1 /* 2 * Copyright (c) 2013, 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_G1CARDCOUNTS_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP 27 28 #include "memory/allocation.hpp" 29 #include "runtime/virtualspace.hpp" 30 #include "utilities/globalDefinitions.hpp" 31 32 class CardTableModRefBS; 33 class G1CollectedHeap; 34 class HeapRegion; 35 36 // Table to track the number of times a card has been refined. Once 37 // a card has been refined a certain number of times, it is 38 // considered 'hot' and its refinement is delayed by inserting the 39 // card into the hot card cache. The card will then be refined when 40 // it is evicted from the hot card cache, or when the hot card cache 41 // is 'drained' during the next evacuation pause. 42 43 class G1CardCounts: public CHeapObj<mtGC> { 44 G1CollectedHeap* _g1h; 45 46 // The table of counts 47 jubyte* _card_counts; 48 49 // Max capacity of the reserved space for the counts table 50 size_t _reserved_max_card_num; 51 52 // Max capacity of the committed space for the counts table 53 size_t _committed_max_card_num; 54 55 // Size of committed space for the counts table 56 size_t _committed_size; 57 58 // CardTable bottom. 59 const jbyte* _ct_bot; 60 61 // Barrier set 62 CardTableModRefBS* _ct_bs; 63 64 // The virtual memory backing the counts table 65 VirtualSpace _card_counts_storage; 66 67 // Returns true if the card counts table has been reserved. 68 bool has_reserved_count_table() { return _card_counts != NULL; } 69 70 // Returns true if the card counts table has been reserved and committed. 71 bool has_count_table() { 72 return has_reserved_count_table() && _committed_max_card_num > 0; 73 } 74 75 size_t ptr_2_card_num(const jbyte* card_ptr) { 76 assert(card_ptr >= _ct_bot, 77 err_msg("Invalid card pointer: " 78 "card_ptr: " PTR_FORMAT ", " 79 "_ct_bot: " PTR_FORMAT, 80 card_ptr, _ct_bot)); 81 size_t card_num = pointer_delta(card_ptr, _ct_bot, sizeof(jbyte)); 82 assert(card_num >= 0 && card_num < _committed_max_card_num, 83 err_msg("card pointer out of range: " PTR_FORMAT, card_ptr)); 84 return card_num; 85 } 86 87 jbyte* card_num_2_ptr(size_t card_num) { 88 assert(card_num >= 0 && card_num < _committed_max_card_num, 89 err_msg("card num out of range: "SIZE_FORMAT, card_num)); 90 return (jbyte*) (_ct_bot + card_num); 91 } 92 93 // Helper routine. 94 // Returns the number of cards that can be counted by the given committed 95 // table size, with a maximum of the number of cards spanned by the max 96 // capacity of the heap. 97 size_t committed_to_card_num(size_t committed_size) { 98 return MIN2(_reserved_max_card_num, committed_size / sizeof(jbyte)); 99 } 100 101 // Clear the counts table for the given (exclusive) index range. 102 void clear_range(size_t from_card_num, size_t to_card_num); 103 104 public: 105 G1CardCounts(G1CollectedHeap* g1h); 106 ~G1CardCounts(); 107 108 void initialize(); 109 110 // Resize the committed space for the card counts table in 111 // response to a resize of the committed space for the heap. 112 void resize(size_t heap_capacity); 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 // Clear the entire card counts table during GC. 126 // Updates the policy stats with the duration. 127 void clear_all(); 128 }; 129 130 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1CARDCOUNTS_HPP