1 /* 2 * Copyright (c) 2005, 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_PARALLEL_PARMARKBITMAP_HPP 26 #define SHARE_VM_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 35 class ParMarkBitMap: public CHeapObj<mtGC> 36 { 37 public: 38 typedef BitMap::idx_t idx_t; 39 40 // Values returned by the iterate() methods. 41 enum IterationStatus { incomplete, complete, full, would_overflow }; 42 43 inline ParMarkBitMap(); 44 bool initialize(MemRegion covered_region); 45 46 // Atomically mark an object as live. 47 bool mark_obj(HeapWord* addr, size_t size); 48 inline bool mark_obj(oop obj, int size); 49 50 // Return whether the specified begin or end bit is set. 51 inline bool is_obj_beg(idx_t bit) const; 52 inline bool is_obj_end(idx_t bit) const; 53 54 // Traditional interface for testing whether an object is marked or not (these 55 // test only the begin bits). 56 inline bool is_marked(idx_t bit) const; 57 inline bool is_marked(HeapWord* addr) const; 58 inline bool is_marked(oop obj) const; 59 60 inline bool is_unmarked(idx_t bit) const; 61 inline bool is_unmarked(HeapWord* addr) const; 62 inline bool is_unmarked(oop obj) const; 63 64 // Convert sizes from bits to HeapWords and back. An object that is n bits 65 // long will be bits_to_words(n) words long. An object that is m words long 66 // will take up words_to_bits(m) bits in the bitmap. 67 inline static size_t bits_to_words(idx_t bits); 68 inline static idx_t words_to_bits(size_t words); 69 70 // Return the size in words of an object given a begin bit and an end bit, or 71 // the equivalent beg_addr and end_addr. 72 inline size_t obj_size(idx_t beg_bit, idx_t end_bit) const; 73 inline size_t obj_size(HeapWord* beg_addr, HeapWord* end_addr) const; 74 75 // Return the size in words of the object (a search is done for the end bit). 76 inline size_t obj_size(idx_t beg_bit) const; 77 inline size_t obj_size(HeapWord* addr) const; 78 79 // Apply live_closure to each live object that lies completely within the 80 // range [live_range_beg, live_range_end). This is used to iterate over the 81 // compacted region of the heap. Return values: 82 // 83 // incomplete The iteration is not complete. The last object that 84 // begins in the range does not end in the range; 85 // closure->source() is set to the start of that object. 86 // 87 // complete The iteration is complete. All objects in the range 88 // were processed and the closure is not full; 89 // closure->source() is set one past the end of the range. 90 // 91 // full The closure is full; closure->source() is set to one 92 // past the end of the last object processed. 93 // 94 // would_overflow The next object in the range would overflow the closure; 95 // closure->source() is set to the start of that object. 96 IterationStatus iterate(ParMarkBitMapClosure* live_closure, 97 idx_t range_beg, idx_t range_end) const; 98 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure, 99 HeapWord* range_beg, 100 HeapWord* range_end) const; 101 102 // Apply live closure as above and additionally apply dead_closure to all dead 103 // space in the range [range_beg, dead_range_end). Note that dead_range_end 104 // must be >= range_end. This is used to iterate over the dense prefix. 105 // 106 // This method assumes that if the first bit in the range (range_beg) is not 107 // marked, then dead space begins at that point and the dead_closure is 108 // applied. Thus callers must ensure that range_beg is not in the middle of a 109 // live object. 110 IterationStatus iterate(ParMarkBitMapClosure* live_closure, 111 ParMarkBitMapClosure* dead_closure, 112 idx_t range_beg, idx_t range_end, 113 idx_t dead_range_end) const; 114 inline IterationStatus iterate(ParMarkBitMapClosure* live_closure, 115 ParMarkBitMapClosure* dead_closure, 116 HeapWord* range_beg, 117 HeapWord* range_end, 118 HeapWord* dead_range_end) const; 119 120 // Return the number of live words in the range [beg_addr, end_obj) due to 121 // objects that start in the range. If a live object extends onto the range, 122 // the caller must detect and account for any live words due to that object. 123 // If a live object extends beyond the end of the range, only the words within 124 // the range are included in the result. The end of the range must be a live object, 125 // which is the case when updating pointers. This allows a branch to be removed 126 // from inside the loop. 127 size_t live_words_in_range(HeapWord* beg_addr, oop end_obj) const; 128 129 inline HeapWord* region_start() const; 130 inline HeapWord* region_end() const; 131 inline size_t region_size() const; 132 inline size_t size() const; 133 134 size_t reserved_byte_size() const { return _reserved_byte_size; } 135 136 // Convert a heap address to/from a bit index. 137 inline idx_t addr_to_bit(HeapWord* addr) const; 138 inline HeapWord* bit_to_addr(idx_t bit) const; 139 140 // Return the bit index of the first marked object that begins (or ends, 141 // respectively) in the range [beg, end). If no object is found, return end. 142 inline idx_t find_obj_beg(idx_t beg, idx_t end) const; 143 inline idx_t find_obj_end(idx_t beg, idx_t end) const; 144 145 inline HeapWord* find_obj_beg(HeapWord* beg, HeapWord* end) const; 146 inline HeapWord* find_obj_end(HeapWord* beg, HeapWord* end) const; 147 148 // Clear a range of bits or the entire bitmap (both begin and end bits are 149 // cleared). 150 inline void clear_range(idx_t beg, idx_t end); 151 152 // Return the number of bits required to represent the specified number of 153 // HeapWords, or the specified region. 154 static inline idx_t bits_required(size_t words); 155 static inline idx_t bits_required(MemRegion covered_region); 156 157 void print_on_error(outputStream* st) const { 158 st->print_cr("Marking Bits: (ParMarkBitMap*) " PTR_FORMAT, p2i(this)); 159 _beg_bits.print_on_error(st, " Begin Bits: "); 160 _end_bits.print_on_error(st, " End Bits: "); 161 } 162 163 #ifdef ASSERT 164 void verify_clear() const; 165 inline void verify_bit(idx_t bit) const; 166 inline void verify_addr(HeapWord* addr) const; 167 #endif // #ifdef ASSERT 168 169 private: 170 // Each bit in the bitmap represents one unit of 'object granularity.' Objects 171 // are double-word aligned in 32-bit VMs, but not in 64-bit VMs, so the 32-bit 172 // granularity is 2, 64-bit is 1. 173 static inline size_t obj_granularity() { return size_t(MinObjAlignment); } 174 static inline int obj_granularity_shift() { return LogMinObjAlignment; } 175 176 HeapWord* _region_start; 177 size_t _region_size; 178 BitMap _beg_bits; 179 BitMap _end_bits; 180 PSVirtualSpace* _virtual_space; 181 size_t _reserved_byte_size; 182 }; 183 184 inline ParMarkBitMap::ParMarkBitMap(): 185 _beg_bits(), _end_bits(), _region_start(NULL), _region_size(0), _virtual_space(NULL), _reserved_byte_size(0) 186 { } 187 188 inline void ParMarkBitMap::clear_range(idx_t beg, idx_t end) 189 { 190 _beg_bits.clear_range(beg, end); 191 _end_bits.clear_range(beg, end); 192 } 193 194 inline ParMarkBitMap::idx_t 195 ParMarkBitMap::bits_required(size_t words) 196 { 197 // Need two bits (one begin bit, one end bit) for each unit of 'object 198 // granularity' in the heap. 199 return words_to_bits(words * 2); 200 } 201 202 inline ParMarkBitMap::idx_t 203 ParMarkBitMap::bits_required(MemRegion covered_region) 204 { 205 return bits_required(covered_region.word_size()); 206 } 207 208 inline HeapWord* 209 ParMarkBitMap::region_start() const 210 { 211 return _region_start; 212 } 213 214 inline HeapWord* 215 ParMarkBitMap::region_end() const 216 { 217 return region_start() + region_size(); 218 } 219 220 inline size_t 221 ParMarkBitMap::region_size() const 222 { 223 return _region_size; 224 } 225 226 inline size_t 227 ParMarkBitMap::size() const 228 { 229 return _beg_bits.size(); 230 } 231 232 inline bool ParMarkBitMap::is_obj_beg(idx_t bit) const 233 { 234 return _beg_bits.at(bit); 235 } 236 237 inline bool ParMarkBitMap::is_obj_end(idx_t bit) const 238 { 239 return _end_bits.at(bit); 240 } 241 242 inline bool ParMarkBitMap::is_marked(idx_t bit) const 243 { 244 return is_obj_beg(bit); 245 } 246 247 inline bool ParMarkBitMap::is_marked(HeapWord* addr) const 248 { 249 return is_marked(addr_to_bit(addr)); 250 } 251 252 inline bool ParMarkBitMap::is_marked(oop obj) const 253 { 254 return is_marked((HeapWord*)obj); 255 } 256 257 inline bool ParMarkBitMap::is_unmarked(idx_t bit) const 258 { 259 return !is_marked(bit); 260 } 261 262 inline bool ParMarkBitMap::is_unmarked(HeapWord* addr) const 263 { 264 return !is_marked(addr); 265 } 266 267 inline bool ParMarkBitMap::is_unmarked(oop obj) const 268 { 269 return !is_marked(obj); 270 } 271 272 inline size_t 273 ParMarkBitMap::bits_to_words(idx_t bits) 274 { 275 return bits << obj_granularity_shift(); 276 } 277 278 inline ParMarkBitMap::idx_t 279 ParMarkBitMap::words_to_bits(size_t words) 280 { 281 return words >> obj_granularity_shift(); 282 } 283 284 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit, idx_t end_bit) const 285 { 286 DEBUG_ONLY(verify_bit(beg_bit);) 287 DEBUG_ONLY(verify_bit(end_bit);) 288 return bits_to_words(end_bit - beg_bit + 1); 289 } 290 291 inline size_t 292 ParMarkBitMap::obj_size(HeapWord* beg_addr, HeapWord* end_addr) const 293 { 294 DEBUG_ONLY(verify_addr(beg_addr);) 295 DEBUG_ONLY(verify_addr(end_addr);) 296 return pointer_delta(end_addr, beg_addr) + obj_granularity(); 297 } 298 299 inline size_t ParMarkBitMap::obj_size(idx_t beg_bit) const 300 { 301 const idx_t end_bit = _end_bits.get_next_one_offset_inline(beg_bit, size()); 302 assert(is_marked(beg_bit), "obj not marked"); 303 assert(end_bit < size(), "end bit missing"); 304 return obj_size(beg_bit, end_bit); 305 } 306 307 inline size_t ParMarkBitMap::obj_size(HeapWord* addr) const 308 { 309 return obj_size(addr_to_bit(addr)); 310 } 311 312 inline ParMarkBitMap::IterationStatus 313 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 314 HeapWord* range_beg, 315 HeapWord* range_end) const 316 { 317 return iterate(live_closure, addr_to_bit(range_beg), addr_to_bit(range_end)); 318 } 319 320 inline ParMarkBitMap::IterationStatus 321 ParMarkBitMap::iterate(ParMarkBitMapClosure* live_closure, 322 ParMarkBitMapClosure* dead_closure, 323 HeapWord* range_beg, 324 HeapWord* range_end, 325 HeapWord* dead_range_end) const 326 { 327 return iterate(live_closure, dead_closure, 328 addr_to_bit(range_beg), addr_to_bit(range_end), 329 addr_to_bit(dead_range_end)); 330 } 331 332 inline bool 333 ParMarkBitMap::mark_obj(oop obj, int size) 334 { 335 return mark_obj((HeapWord*)obj, (size_t)size); 336 } 337 338 inline BitMap::idx_t 339 ParMarkBitMap::addr_to_bit(HeapWord* addr) const 340 { 341 DEBUG_ONLY(verify_addr(addr);) 342 return words_to_bits(pointer_delta(addr, region_start())); 343 } 344 345 inline HeapWord* 346 ParMarkBitMap::bit_to_addr(idx_t bit) const 347 { 348 DEBUG_ONLY(verify_bit(bit);) 349 return region_start() + bits_to_words(bit); 350 } 351 352 inline ParMarkBitMap::idx_t 353 ParMarkBitMap::find_obj_beg(idx_t beg, idx_t end) const 354 { 355 return _beg_bits.get_next_one_offset_inline_aligned_right(beg, end); 356 } 357 358 inline ParMarkBitMap::idx_t 359 ParMarkBitMap::find_obj_end(idx_t beg, idx_t end) const 360 { 361 return _end_bits.get_next_one_offset_inline_aligned_right(beg, end); 362 } 363 364 inline HeapWord* 365 ParMarkBitMap::find_obj_beg(HeapWord* beg, HeapWord* end) const 366 { 367 const idx_t beg_bit = addr_to_bit(beg); 368 const idx_t end_bit = addr_to_bit(end); 369 const idx_t search_end = BitMap::word_align_up(end_bit); 370 const idx_t res_bit = MIN2(find_obj_beg(beg_bit, search_end), end_bit); 371 return bit_to_addr(res_bit); 372 } 373 374 inline HeapWord* 375 ParMarkBitMap::find_obj_end(HeapWord* beg, HeapWord* end) const 376 { 377 const idx_t beg_bit = addr_to_bit(beg); 378 const idx_t end_bit = addr_to_bit(end); 379 const idx_t search_end = BitMap::word_align_up(end_bit); 380 const idx_t res_bit = MIN2(find_obj_end(beg_bit, search_end), end_bit); 381 return bit_to_addr(res_bit); 382 } 383 384 #ifdef ASSERT 385 inline void ParMarkBitMap::verify_bit(idx_t bit) const { 386 // Allow one past the last valid bit; useful for loop bounds. 387 assert(bit <= _beg_bits.size(), "bit out of range"); 388 } 389 390 inline void ParMarkBitMap::verify_addr(HeapWord* addr) const { 391 // Allow one past the last valid address; useful for loop bounds. 392 assert(addr >= region_start(), 393 "addr too small, addr: " PTR_FORMAT " region start: " PTR_FORMAT, p2i(addr), p2i(region_start())); 394 assert(addr <= region_end(), 395 "addr too big, addr: " PTR_FORMAT " region end: " PTR_FORMAT, p2i(addr), p2i(region_end())); 396 } 397 #endif // #ifdef ASSERT 398 399 #endif // SHARE_VM_GC_PARALLEL_PARMARKBITMAP_HPP