1 /* 2 * Copyright (c) 2017, 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_G1CONCURRENTMARKBITMAP_HPP 26 #define SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP 27 28 #include "gc/g1/g1RegionToSpaceMapper.hpp" 29 #include "memory/memRegion.hpp" 30 #include "oops/oopsHierarchy.hpp" 31 #include "utilities/bitMap.hpp" 32 #include "utilities/globalDefinitions.hpp" 33 #include "utilities/macros.hpp" 34 35 class G1CMBitMap; 36 class G1CMTask; 37 class G1ConcurrentMark; 38 class HeapRegion; 39 40 // Closure for iteration over bitmaps 41 class G1CMBitMapClosure { 42 private: 43 G1ConcurrentMark* const _cm; 44 G1CMTask* const _task; 45 public: 46 G1CMBitMapClosure(G1CMTask *task, G1ConcurrentMark* cm) : _task(task), _cm(cm) { } 47 48 bool do_addr(HeapWord* const addr); 49 }; 50 51 class G1CMBitMapMappingChangedListener : public G1MappingChangedListener { 52 private: 53 G1CMBitMap* _bm; 54 public: 55 G1CMBitMapMappingChangedListener() : _bm(NULL) {} 56 57 void set_bitmap(G1CMBitMap* bm) { _bm = bm; } 58 59 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 60 }; 61 62 // A generic mark bitmap for concurrent marking. This is essentially a wrapper 63 // around the BitMap class that is based on HeapWords, with one bit per (1 << _shifter) HeapWords. 64 class G1CMBitMap { 65 private: 66 MemRegion _covered; // The heap area covered by this bitmap. 67 68 const int _shifter; // Shift amount from heap index to bit index in the bitmap. 69 70 BitMapView _bm; // The actual bitmap. 71 72 G1CMBitMapMappingChangedListener _listener; 73 74 inline void check_mark(HeapWord* addr) NOT_DEBUG_RETURN; 75 76 // Convert from bit offset to address. 77 HeapWord* offset_to_addr(size_t offset) const { 78 return _covered.start() + (offset << _shifter); 79 } 80 // Convert from address to bit offset. 81 size_t addr_to_offset(const HeapWord* addr) const { 82 return pointer_delta(addr, _covered.start()) >> _shifter; 83 } 84 public: 85 static size_t compute_size(size_t heap_size); 86 // Returns the amount of bytes on the heap between two marks in the bitmap. 87 static size_t mark_distance(); 88 // Returns how many bytes (or bits) of the heap a single byte (or bit) of the 89 // mark bitmap corresponds to. This is the same as the mark distance above. 90 static size_t heap_map_factor() { 91 return mark_distance(); 92 } 93 94 G1CMBitMap() : _covered(), _bm(), _shifter(LogMinObjAlignment), _listener() { _listener.set_bitmap(this); } 95 96 // Initializes the underlying BitMap to cover the given area. 97 void initialize(MemRegion heap, G1RegionToSpaceMapper* storage); 98 99 // Read marks 100 bool is_marked(oop obj) const; 101 bool is_marked(HeapWord* addr) const { 102 assert(_covered.contains(addr), 103 "Address " PTR_FORMAT " is outside underlying space from " PTR_FORMAT " to " PTR_FORMAT, 104 p2i(addr), p2i(_covered.start()), p2i(_covered.end())); 105 return _bm.at(addr_to_offset(addr)); 106 } 107 108 // Apply the closure to the addresses that correspond to marked bits in the bitmap. 109 inline bool iterate(G1CMBitMapClosure* cl, MemRegion mr); 110 111 // Return the address corresponding to the next marked bit at or after 112 // "addr", and before "limit", if "limit" is non-NULL. If there is no 113 // such bit, returns "limit" if that is non-NULL, or else "endWord()". 114 inline HeapWord* get_next_marked_addr(const HeapWord* addr, 115 const HeapWord* limit) const; 116 117 // The argument addr should be the start address of a valid object 118 inline HeapWord* addr_after_obj(HeapWord* addr); 119 120 void print_on_error(outputStream* st, const char* prefix) const; 121 122 // Write marks. 123 inline void mark(HeapWord* addr); 124 inline void clear(HeapWord* addr); 125 inline void clear(oop obj); 126 inline bool par_mark(HeapWord* addr); 127 inline bool par_mark(oop obj); 128 129 void clear_range(MemRegion mr); 130 void clear_region(HeapRegion* hr); 131 }; 132 133 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP