1 /* 2 * Copyright (c) 2001, 2014, 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_CONCURRENTMARK_INLINE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP 27 28 #include "gc_implementation/g1/concurrentMark.hpp" 29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp" 30 31 // Utility routine to set an exclusive range of cards on the given 32 // card liveness bitmap 33 inline void ConcurrentMark::set_card_bitmap_range(BitMap* card_bm, 34 BitMap::idx_t start_idx, 35 BitMap::idx_t end_idx, 36 bool is_par) { 37 38 // Set the exclusive bit range [start_idx, end_idx). 39 assert((end_idx - start_idx) > 0, "at least one card"); 40 assert(end_idx <= card_bm->size(), "sanity"); 41 42 // Silently clip the end index 43 end_idx = MIN2(end_idx, card_bm->size()); 44 45 // For small ranges use a simple loop; otherwise use set_range or 46 // use par_at_put_range (if parallel). The range is made up of the 47 // cards that are spanned by an object/mem region so 8 cards will 48 // allow up to object sizes up to 4K to be handled using the loop. 49 if ((end_idx - start_idx) <= 8) { 50 for (BitMap::idx_t i = start_idx; i < end_idx; i += 1) { 51 if (is_par) { 52 card_bm->par_set_bit(i); 53 } else { 54 card_bm->set_bit(i); 55 } 56 } 57 } else { 58 // Note BitMap::par_at_put_range() and BitMap::set_range() are exclusive. 59 if (is_par) { 60 card_bm->par_at_put_range(start_idx, end_idx, true); 61 } else { 62 card_bm->set_range(start_idx, end_idx); 63 } 64 } 65 } 66 67 // Returns the index in the liveness accounting card bitmap 68 // for the given address 69 inline BitMap::idx_t ConcurrentMark::card_bitmap_index_for(HeapWord* addr) { 70 // Below, the term "card num" means the result of shifting an address 71 // by the card shift -- address 0 corresponds to card number 0. One 72 // must subtract the card num of the bottom of the heap to obtain a 73 // card table index. 74 intptr_t card_num = intptr_t(uintptr_t(addr) >> CardTableModRefBS::card_shift); 75 return card_num - heap_bottom_card_num(); 76 } 77 78 // Counts the given memory region in the given task/worker 79 // counting data structures. 80 inline void ConcurrentMark::count_region(MemRegion mr, HeapRegion* hr, 81 size_t* marked_bytes_array, 82 BitMap* task_card_bm) { 83 G1CollectedHeap* g1h = _g1h; 84 CardTableModRefBS* ct_bs = g1h->g1_barrier_set(); 85 86 HeapWord* start = mr.start(); 87 HeapWord* end = mr.end(); 88 size_t region_size_bytes = mr.byte_size(); 89 uint index = hr->hrs_index(); 90 91 assert(!hr->continuesHumongous(), "should not be HC region"); 92 assert(hr == g1h->heap_region_containing(start), "sanity"); 93 assert(hr == g1h->heap_region_containing(mr.last()), "sanity"); 94 assert(marked_bytes_array != NULL, "pre-condition"); 95 assert(task_card_bm != NULL, "pre-condition"); 96 97 // Add to the task local marked bytes for this region. 98 marked_bytes_array[index] += region_size_bytes; 99 100 BitMap::idx_t start_idx = card_bitmap_index_for(start); 101 BitMap::idx_t end_idx = card_bitmap_index_for(end); 102 103 // Note: if we're looking at the last region in heap - end 104 // could be actually just beyond the end of the heap; end_idx 105 // will then correspond to a (non-existent) card that is also 106 // just beyond the heap. 107 if (g1h->is_in_g1_reserved(end) && !ct_bs->is_card_aligned(end)) { 108 // end of region is not card aligned - increment to cover 109 // all the cards spanned by the region. 110 end_idx += 1; 111 } 112 // The card bitmap is task/worker specific => no need to use 113 // the 'par' BitMap routines. 114 // Set bits in the exclusive bit range [start_idx, end_idx). 115 set_card_bitmap_range(task_card_bm, start_idx, end_idx, false /* is_par */); 116 } 117 118 // Counts the given memory region in the task/worker counting 119 // data structures for the given worker id. 120 inline void ConcurrentMark::count_region(MemRegion mr, 121 HeapRegion* hr, 122 uint worker_id) { 123 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id); 124 BitMap* task_card_bm = count_card_bitmap_for(worker_id); 125 count_region(mr, hr, marked_bytes_array, task_card_bm); 126 } 127 128 // Counts the given memory region, which may be a single object, in the 129 // task/worker counting data structures for the given worker id. 130 inline void ConcurrentMark::count_region(MemRegion mr, uint worker_id) { 131 HeapWord* addr = mr.start(); 132 HeapRegion* hr = _g1h->heap_region_containing_raw(addr); 133 count_region(mr, hr, worker_id); 134 } 135 136 // Counts the given object in the given task/worker counting data structures. 137 inline void ConcurrentMark::count_object(oop obj, 138 HeapRegion* hr, 139 size_t* marked_bytes_array, 140 BitMap* task_card_bm) { 141 MemRegion mr((HeapWord*)obj, obj->size()); 142 count_region(mr, hr, marked_bytes_array, task_card_bm); 143 } 144 145 // Counts the given object in the task/worker counting data 146 // structures for the given worker id. 147 inline void ConcurrentMark::count_object(oop obj, 148 HeapRegion* hr, 149 uint worker_id) { 150 size_t* marked_bytes_array = count_marked_bytes_array_for(worker_id); 151 BitMap* task_card_bm = count_card_bitmap_for(worker_id); 152 HeapWord* addr = (HeapWord*) obj; 153 count_object(obj, hr, marked_bytes_array, task_card_bm); 154 } 155 156 // Attempts to mark the given object and, if successful, counts 157 // the object in the given task/worker counting structures. 158 inline bool ConcurrentMark::par_mark_and_count(oop obj, 159 HeapRegion* hr, 160 size_t* marked_bytes_array, 161 BitMap* task_card_bm) { 162 HeapWord* addr = (HeapWord*)obj; 163 if (_nextMarkBitMap->parMark(addr)) { 164 // Update the task specific count data for the object. 165 count_object(obj, hr, marked_bytes_array, task_card_bm); 166 return true; 167 } 168 return false; 169 } 170 171 // Attempts to mark the given object and, if successful, counts 172 // the object in the task/worker counting structures for the 173 // given worker id. 174 inline bool ConcurrentMark::par_mark_and_count(oop obj, 175 size_t word_size, 176 HeapRegion* hr, 177 uint worker_id) { 178 HeapWord* addr = (HeapWord*)obj; 179 if (_nextMarkBitMap->parMark(addr)) { 180 MemRegion mr(addr, word_size); 181 count_region(mr, hr, worker_id); 182 return true; 183 } 184 return false; 185 } 186 187 // Attempts to mark the given object and, if successful, counts 188 // the object in the task/worker counting structures for the 189 // given worker id. 190 inline bool ConcurrentMark::par_mark_and_count(oop obj, 191 HeapRegion* hr, 192 uint worker_id) { 193 HeapWord* addr = (HeapWord*)obj; 194 if (_nextMarkBitMap->parMark(addr)) { 195 // Update the task specific count data for the object. 196 count_object(obj, hr, worker_id); 197 return true; 198 } 199 return false; 200 } 201 202 // As above - but we don't know the heap region containing the 203 // object and so have to supply it. 204 inline bool ConcurrentMark::par_mark_and_count(oop obj, uint worker_id) { 205 HeapWord* addr = (HeapWord*)obj; 206 HeapRegion* hr = _g1h->heap_region_containing_raw(addr); 207 return par_mark_and_count(obj, hr, worker_id); 208 } 209 210 // Similar to the above routine but we already know the size, in words, of 211 // the object that we wish to mark/count 212 inline bool ConcurrentMark::par_mark_and_count(oop obj, 213 size_t word_size, 214 uint worker_id) { 215 HeapWord* addr = (HeapWord*)obj; 216 if (_nextMarkBitMap->parMark(addr)) { 217 // Update the task specific count data for the object. 218 MemRegion mr(addr, word_size); 219 count_region(mr, worker_id); 220 return true; 221 } 222 return false; 223 } 224 225 // Unconditionally mark the given object, and unconditionally count 226 // the object in the counting structures for worker id 0. 227 // Should *not* be called from parallel code. 228 inline bool ConcurrentMark::mark_and_count(oop obj, HeapRegion* hr) { 229 HeapWord* addr = (HeapWord*)obj; 230 _nextMarkBitMap->mark(addr); 231 // Update the task specific count data for the object. 232 count_object(obj, hr, 0 /* worker_id */); 233 return true; 234 } 235 236 // As above - but we don't have the heap region containing the 237 // object, so we have to supply it. 238 inline bool ConcurrentMark::mark_and_count(oop obj) { 239 HeapWord* addr = (HeapWord*)obj; 240 HeapRegion* hr = _g1h->heap_region_containing_raw(addr); 241 return mark_and_count(obj, hr); 242 } 243 244 inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { 245 HeapWord* start_addr = MAX2(startWord(), mr.start()); 246 HeapWord* end_addr = MIN2(endWord(), mr.end()); 247 248 if (end_addr > start_addr) { 249 // Right-open interval [start-offset, end-offset). 250 BitMap::idx_t start_offset = heapWordToOffset(start_addr); 251 BitMap::idx_t end_offset = heapWordToOffset(end_addr); 252 253 start_offset = _bm.get_next_one_offset(start_offset, end_offset); 254 while (start_offset < end_offset) { 255 if (!cl->do_bit(start_offset)) { 256 return false; 257 } 258 HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr); 259 BitMap::idx_t next_offset = heapWordToOffset(next_addr); 260 start_offset = _bm.get_next_one_offset(next_offset, end_offset); 261 } 262 } 263 return true; 264 } 265 266 inline bool CMBitMapRO::iterate(BitMapClosure* cl) { 267 MemRegion mr(startWord(), sizeInWords()); 268 return iterate(cl, mr); 269 } 270 271 inline void CMTask::push(oop obj) { 272 HeapWord* objAddr = (HeapWord*) obj; 273 assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); 274 assert(!_g1h->is_on_master_free_list( 275 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant"); 276 assert(!_g1h->is_obj_ill(obj), "invariant"); 277 assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); 278 279 if (_cm->verbose_high()) { 280 gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj)); 281 } 282 283 if (!_task_queue->push(obj)) { 284 // The local task queue looks full. We need to push some entries 285 // to the global stack. 286 287 if (_cm->verbose_medium()) { 288 gclog_or_tty->print_cr("[%u] task queue overflow, " 289 "moving entries to the global stack", 290 _worker_id); 291 } 292 move_entries_to_global_stack(); 293 294 // this should succeed since, even if we overflow the global 295 // stack, we should have definitely removed some entries from the 296 // local queue. So, there must be space on it. 297 bool success = _task_queue->push(obj); 298 assert(success, "invariant"); 299 } 300 301 statsOnly( int tmp_size = _task_queue->size(); 302 if (tmp_size > _local_max_size) { 303 _local_max_size = tmp_size; 304 } 305 ++_local_pushes ); 306 } 307 308 // This determines whether the method below will check both the local 309 // and global fingers when determining whether to push on the stack a 310 // gray object (value 1) or whether it will only check the global one 311 // (value 0). The tradeoffs are that the former will be a bit more 312 // accurate and possibly push less on the stack, but it might also be 313 // a little bit slower. 314 315 #define _CHECK_BOTH_FINGERS_ 1 316 317 inline void CMTask::deal_with_reference(oop obj) { 318 if (_cm->verbose_high()) { 319 gclog_or_tty->print_cr("[%u] we're dealing with reference = "PTR_FORMAT, 320 _worker_id, p2i((void*) obj)); 321 } 322 323 ++_refs_reached; 324 325 HeapWord* objAddr = (HeapWord*) obj; 326 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); 327 if (_g1h->is_in_g1_reserved(objAddr)) { 328 assert(obj != NULL, "null check is implicit"); 329 if (!_nextMarkBitMap->isMarked(objAddr)) { 330 // Only get the containing region if the object is not marked on the 331 // bitmap (otherwise, it's a waste of time since we won't do 332 // anything with it). 333 HeapRegion* hr = _g1h->heap_region_containing_raw(obj); 334 if (!hr->obj_allocated_since_next_marking(obj)) { 335 if (_cm->verbose_high()) { 336 gclog_or_tty->print_cr("[%u] "PTR_FORMAT" is not considered marked", 337 _worker_id, p2i((void*) obj)); 338 } 339 340 // we need to mark it first 341 if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) { 342 // No OrderAccess:store_load() is needed. It is implicit in the 343 // CAS done in CMBitMap::parMark() call in the routine above. 344 HeapWord* global_finger = _cm->finger(); 345 346 #if _CHECK_BOTH_FINGERS_ 347 // we will check both the local and global fingers 348 349 if (_finger != NULL && objAddr < _finger) { 350 if (_cm->verbose_high()) { 351 gclog_or_tty->print_cr("[%u] below the local finger ("PTR_FORMAT"), " 352 "pushing it", _worker_id, p2i(_finger)); 353 } 354 push(obj); 355 } else if (_curr_region != NULL && objAddr < _region_limit) { 356 // do nothing 357 } else if (objAddr < global_finger) { 358 // Notice that the global finger might be moving forward 359 // concurrently. This is not a problem. In the worst case, we 360 // mark the object while it is above the global finger and, by 361 // the time we read the global finger, it has moved forward 362 // passed this object. In this case, the object will probably 363 // be visited when a task is scanning the region and will also 364 // be pushed on the stack. So, some duplicate work, but no 365 // correctness problems. 366 367 if (_cm->verbose_high()) { 368 gclog_or_tty->print_cr("[%u] below the global finger " 369 "("PTR_FORMAT"), pushing it", 370 _worker_id, p2i(global_finger)); 371 } 372 push(obj); 373 } else { 374 // do nothing 375 } 376 #else // _CHECK_BOTH_FINGERS_ 377 // we will only check the global finger 378 379 if (objAddr < global_finger) { 380 // see long comment above 381 382 if (_cm->verbose_high()) { 383 gclog_or_tty->print_cr("[%u] below the global finger " 384 "("PTR_FORMAT"), pushing it", 385 _worker_id, p2i(global_finger)); 386 } 387 push(obj); 388 } 389 #endif // _CHECK_BOTH_FINGERS_ 390 } 391 } 392 } 393 } 394 } 395 396 inline void ConcurrentMark::markPrev(oop p) { 397 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity"); 398 // Note we are overriding the read-only view of the prev map here, via 399 // the cast. 400 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p); 401 } 402 403 inline void ConcurrentMark::grayRoot(oop obj, size_t word_size, 404 uint worker_id, HeapRegion* hr) { 405 assert(obj != NULL, "pre-condition"); 406 HeapWord* addr = (HeapWord*) obj; 407 if (hr == NULL) { 408 hr = _g1h->heap_region_containing_raw(addr); 409 } else { 410 assert(hr->is_in(addr), "pre-condition"); 411 } 412 assert(hr != NULL, "sanity"); 413 // Given that we're looking for a region that contains an object 414 // header it's impossible to get back a HC region. 415 assert(!hr->continuesHumongous(), "sanity"); 416 417 // We cannot assert that word_size == obj->size() given that obj 418 // might not be in a consistent state (another thread might be in 419 // the process of copying it). So the best thing we can do is to 420 // assert that word_size is under an upper bound which is its 421 // containing region's capacity. 422 assert(word_size * HeapWordSize <= hr->capacity(), 423 err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT, 424 word_size * HeapWordSize, hr->capacity(), 425 HR_FORMAT_PARAMS(hr))); 426 427 if (addr < hr->next_top_at_mark_start()) { 428 if (!_nextMarkBitMap->isMarked(addr)) { 429 par_mark_and_count(obj, word_size, hr, worker_id); 430 } 431 } 432 } 433 434 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP