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/allocation.hpp" 30 #include "memory/memRegion.hpp" 31 #include "oops/oopsHierarchy.hpp" 32 #include "utilities/bitMap.hpp" 33 #include "utilities/globalDefinitions.hpp" 34 #include "utilities/macros.hpp" 35 36 class G1CMBitMap; 37 class G1CMTask; 38 class G1ConcurrentMark; 39 class HeapRegion; 40 41 // Closure for iteration over bitmaps 42 class G1CMBitMapClosure VALUE_OBJ_CLASS_SPEC { 43 private: 44 G1ConcurrentMark* const _cm; 45 G1CMTask* const _task; 46 public: 47 G1CMBitMapClosure(G1CMTask *task, G1ConcurrentMark* cm) : _task(task), _cm(cm) { } 48 49 bool do_addr(HeapWord* const addr); 50 }; 51 52 class G1CMBitMapMappingChangedListener : public G1MappingChangedListener { 53 private: 54 G1CMBitMap* _bm; 55 public: 56 G1CMBitMapMappingChangedListener() : _bm(NULL) {} 57 58 void set_bitmap(G1CMBitMap* bm) { _bm = bm; } 59 60 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled); 61 }; 62 63 // A generic mark bitmap for concurrent marking. This is essentially a wrapper 64 // around the BitMap class that is based on HeapWords, with one bit per (1 << _shifter) HeapWords. 65 class G1CMBitMap VALUE_OBJ_CLASS_SPEC { 66 private: 67 MemRegion _covered; // The heap area covered by this bitmap. 68 69 const int _shifter; // Shift amount from heap index to bit index in the bitmap. 70 71 BitMapView _bm; // The actual bitmap. 72 73 G1CMBitMapMappingChangedListener _listener; 74 75 inline void check_mark(HeapWord* addr) NOT_DEBUG_RETURN; 76 77 // Convert from bit offset to address. 78 HeapWord* offset_to_addr(size_t offset) const { 79 return _covered.start() + (offset << _shifter); 80 } 81 // Convert from address to bit offset. 82 size_t addr_to_offset(const HeapWord* addr) const { 83 return pointer_delta(addr, _covered.start()) >> _shifter; 84 } 85 public: 86 static size_t compute_size(size_t heap_size); 87 // Returns the amount of bytes on the heap between two marks in the bitmap. 88 static size_t mark_distance(); 89 // Returns how many bytes (or bits) of the heap a single byte (or bit) of the 90 // mark bitmap corresponds to. This is the same as the mark distance above. 91 static size_t heap_map_factor() { 92 return mark_distance(); 93 } 94 95 G1CMBitMap() : _covered(), _bm(), _shifter(LogMinObjAlignment), _listener() { _listener.set_bitmap(this); } 96 97 // Initializes the underlying BitMap to cover the given area. 98 void initialize(MemRegion heap, G1RegionToSpaceMapper* storage); 99 100 // Read marks 101 bool is_marked(oop obj) const; 102 bool is_marked(HeapWord* addr) const { 103 assert(_covered.contains(addr), 104 "Address " PTR_FORMAT " is outside underlying space from " PTR_FORMAT " to " PTR_FORMAT, 105 p2i(addr), p2i(_covered.start()), p2i(_covered.end())); 106 return _bm.at(addr_to_offset(addr)); 107 } 108 109 // Apply the closure to the addresses that correspond to marked bits in the bitmap. 110 inline bool iterate(G1CMBitMapClosure* cl, MemRegion mr); 111 112 // Return the address corresponding to the next marked bit at or after 113 // "addr", and before "limit", if "limit" is non-NULL. If there is no 114 // such bit, returns "limit" if that is non-NULL, or else "endWord()". 115 inline HeapWord* get_next_marked_addr(const HeapWord* addr, 116 const HeapWord* limit) const; 117 118 // The argument addr should be the start address of a valid object 119 inline HeapWord* addr_after_obj(HeapWord* addr); 120 121 void print_on_error(outputStream* st, const char* prefix) const; 122 123 // Write marks. 124 inline void mark(HeapWord* addr); 125 inline void clear(HeapWord* addr); 126 inline void clear(oop obj); 127 inline bool par_mark(HeapWord* addr); 128 inline bool par_mark(oop obj); 129 130 void clear_range(MemRegion mr); 131 void clear_region(HeapRegion* hr); 132 }; 133 134 #endif // SHARE_VM_GC_G1_G1CONCURRENTMARKBITMAP_HPP