1 /* 2 * Copyright (c) 2005, 2019, 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_GC_PARALLEL_PARMARKBITMAP_HPP 26 #define SHARE_GC_PARALLEL_PARMARKBITMAP_HPP 27 28 #include "memory/memRegion.hpp" 29 #include "oops/oop.hpp" 30 #include "utilities/bitMap.hpp" 31 32 class ParMarkBitMapClosure; 33 class PSVirtualSpace; 34 class ParCompactionManager; 35 36 class ParMarkBitMap: public CHeapObj<mtGC> 37 { 38 public: 39 typedef BitMap::idx_t idx_t; 40 41 // Values returned by the iterate() methods. 42 enum IterationStatus { incomplete, complete, full, would_overflow }; 43 44 inline ParMarkBitMap(); 45 bool initialize(MemRegion covered_region); 46 47 // Atomically mark an object as live. 48 bool mark_obj(HeapWord* addr, size_t size); 49 inline bool mark_obj(oop obj, int size); 50 51 // Return whether the specified begin or end bit is set. 52 inline bool is_obj_beg(idx_t bit) const; 53 inline bool is_obj_end(idx_t bit) const; 54 55 // Traditional interface for testing whether an object is marked or not (these 56 // test only the begin bits). 57 inline bool is_marked(idx_t bit) const; 58 inline bool is_marked(HeapWord* addr) const; 59 inline bool is_marked(oop obj) const; 60 61 inline bool is_unmarked(idx_t bit) const; 62 inline bool is_unmarked(HeapWord* addr) const; 63 inline bool is_unmarked(oop obj) const; 64 65 // Convert sizes from bits to HeapWords and back. An object that is n bits 66 // long will be bits_to_words(n) words long. An object that is m words long 67 // will take up words_to_bits(m) bits in the bitmap. 68 inline static size_t bits_to_words(idx_t bits); 69 inline static idx_t words_to_bits(size_t words); 70 71 // Return the size in words of an object given a begin bit and an end bit, or 72 // the equivalent beg_addr and end_addr. 73 inline size_t obj_size(idx_t beg_bit, idx_t end_bit) const; 74 inline size_t obj_size(HeapWord* beg_addr, HeapWord* end_addr) const; 75 76 // Return the size in words of the object (a search is done for the end bit). 77 inline size_t obj_size(idx_t beg_bit) const; 78 inline size_t obj_size(HeapWord* addr) const; 79 80 // Apply live_closure to each live object that lies completely within the 81 // range [live_range_beg, live_range_end). This is used to iterate over the 82 // compacted region of the heap. Return values: 83 // 84 // incomplete The iteration is not complete. The last object that 85 // begins in the range does not end in the range; 86 // closure->source() is set to the start of that object. 87 // 88 // complete The iteration is complete. All objects in the range 89 // were processed and the closure is not full; 90 // closure->source() is set one past the end of the range. 91 // 92 // full The closure is full; closure->source() is set to one 93 // past the end of the last object processed. 94 // 95 // would_overflow The next object in the range would overflow the closure; 96 // closure->source() is set to the start of that object. 97 IterationStatus iterate(ParMarkBitMapClosure* live_closure, 98 idx_t range_beg, idx_t range_end) const; 99 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure, 100 HeapWord* range_beg, 101 HeapWord* range_end) const; 102 103 // Apply live closure as above and additionally apply dead_closure to all dead 104 // space in the range [range_beg, dead_range_end). Note that dead_range_end 105 // must be >= range_end. This is used to iterate over the dense prefix. 106 // 107 // This method assumes that if the first bit in the range (range_beg) is not 108 // marked, then dead space begins at that point and the dead_closure is 109 // applied. Thus callers must ensure that range_beg is not in the middle of a 110 // live object. 111 IterationStatus iterate(ParMarkBitMapClosure* live_closure, 112 ParMarkBitMapClosure* dead_closure, 113 idx_t range_beg, idx_t range_end, 114 idx_t dead_range_end) const; 115 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure, 116 ParMarkBitMapClosure* dead_closure, 117 HeapWord* range_beg, 118 HeapWord* range_end, 119 HeapWord* dead_range_end) const; 120 121 // Return the number of live words in the range [beg_addr, end_obj) due to 122 // objects that start in the range. If a live object extends onto the range, 123 // the caller must detect and account for any live words due to that object. 124 // If a live object extends beyond the end of the range, only the words within 125 // the range are included in the result. The end of the range must be a live object, 126 // which is the case when updating pointers. This allows a branch to be removed 127 // from inside the loop. 128 size_t live_words_in_range(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const; 129 130 inline HeapWord* region_start() const; 131 inline HeapWord* region_end() const; 132 inline size_t region_size() const; 133 inline size_t size() const; 134 reserved_byte_size() const135 size_t reserved_byte_size() const { return _reserved_byte_size; } 136 137 // Convert a heap address to/from a bit index. 138 inline idx_t addr_to_bit(HeapWord* addr) const; 139 inline HeapWord* bit_to_addr(idx_t bit) const; 140 141 // Return word-aligned up range_end, which must not be greater than size(). 142 inline idx_t align_range_end(idx_t range_end) const; 143 144 // Return the bit index of the first marked object that begins (or ends, 145 // respectively) in the range [beg, end). If no object is found, return end. 146 // end must be word-aligned. 147 inline idx_t find_obj_beg(idx_t beg, idx_t end) const; 148 inline idx_t find_obj_end(idx_t beg, idx_t end) const; 149 150 inline HeapWord* find_obj_beg(HeapWord* beg, HeapWord* end) const; 151 inline HeapWord* find_obj_end(HeapWord* beg, HeapWord* end) const; 152 153 // Clear a range of bits or the entire bitmap (both begin and end bits are 154 // cleared). 155 inline void clear_range(idx_t beg, idx_t end); 156 157 // Return the number of bits required to represent the specified number of 158 // HeapWords, or the specified region. 159 static inline idx_t bits_required(size_t words); 160 static inline idx_t bits_required(MemRegion covered_region); 161 print_on_error(outputStream * st) const162 void print_on_error(outputStream* st) const { 163 st->print_cr("Marking Bits: (ParMarkBitMap*) " PTR_FORMAT, p2i(this)); 164 _beg_bits.print_on_error(st, " Begin Bits: "); 165 _end_bits.print_on_error(st, " End Bits: "); 166 } 167 168 #ifdef ASSERT 169 void verify_clear() const; 170 inline void verify_bit(idx_t bit) const; 171 inline void verify_addr(HeapWord* addr) const; 172 #endif // #ifdef ASSERT 173 174 private: 175 size_t live_words_in_range_helper(HeapWord* beg_addr, oop end_obj) const; 176 177 bool is_live_words_in_range_in_cache(ParCompactionManager* cm, HeapWord* beg_addr) const; 178 size_t live_words_in_range_use_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj) const; 179 void update_live_words_in_range_cache(ParCompactionManager* cm, HeapWord* beg_addr, oop end_obj, size_t result) const; 180 181 // Each bit in the bitmap represents one unit of 'object granularity.' Objects 182 // are double-word aligned in 32-bit VMs, but not in 64-bit VMs, so the 32-bit 183 // granularity is 2, 64-bit is 1. obj_granularity()184 static inline size_t obj_granularity() { return size_t(MinObjAlignment); } obj_granularity_shift()185 static inline int obj_granularity_shift() { return LogMinObjAlignment; } 186 187 HeapWord* _region_start; 188 size_t _region_size; 189 BitMapView _beg_bits; 190 BitMapView _end_bits; 191 PSVirtualSpace* _virtual_space; 192 size_t _reserved_byte_size; 193 }; 194 195 #endif // SHARE_GC_PARALLEL_PARMARKBITMAP_HPP 196