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->hrm_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 - incremement 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 object in the given task/worker counting data structures. 129 inline void ConcurrentMark::count_object(oop obj, 130 HeapRegion* hr, 131 size_t* marked_bytes_array, 132 BitMap* task_card_bm) { 133 MemRegion mr((HeapWord*)obj, obj->size()); 134 count_region(mr, hr, marked_bytes_array, task_card_bm); 135 } 136 137 // Attempts to mark the given object and, if successful, counts 138 // the object in the given task/worker counting structures. 139 inline bool ConcurrentMark::par_mark_and_count(oop obj, 140 HeapRegion* hr, 141 size_t* marked_bytes_array, 142 BitMap* task_card_bm) { 143 HeapWord* addr = (HeapWord*)obj; 144 if (_nextMarkBitMap->parMark(addr)) { 145 // Update the task specific count data for the object. 146 count_object(obj, hr, marked_bytes_array, task_card_bm); 147 return true; 148 } 149 return false; 150 } 151 152 // Attempts to mark the given object and, if successful, counts 153 // the object in the task/worker counting structures for the 154 // given worker id. 155 inline bool ConcurrentMark::par_mark_and_count(oop obj, 156 size_t word_size, 157 HeapRegion* hr, 158 uint worker_id) { 159 HeapWord* addr = (HeapWord*)obj; 160 if (_nextMarkBitMap->parMark(addr)) { 161 MemRegion mr(addr, word_size); 162 count_region(mr, hr, worker_id); 163 return true; 164 } 165 return false; 166 } 167 168 inline bool CMBitMapRO::iterate(BitMapClosure* cl, MemRegion mr) { 169 HeapWord* start_addr = MAX2(startWord(), mr.start()); 170 HeapWord* end_addr = MIN2(endWord(), mr.end()); 171 172 if (end_addr > start_addr) { 173 // Right-open interval [start-offset, end-offset). 174 BitMap::idx_t start_offset = heapWordToOffset(start_addr); 175 BitMap::idx_t end_offset = heapWordToOffset(end_addr); 176 177 start_offset = _bm.get_next_one_offset(start_offset, end_offset); 178 while (start_offset < end_offset) { 179 if (!cl->do_bit(start_offset)) { 180 return false; 181 } 182 HeapWord* next_addr = MIN2(nextObject(offsetToHeapWord(start_offset)), end_addr); 183 BitMap::idx_t next_offset = heapWordToOffset(next_addr); 184 start_offset = _bm.get_next_one_offset(next_offset, end_offset); 185 } 186 } 187 return true; 188 } 189 190 inline bool CMBitMapRO::iterate(BitMapClosure* cl) { 191 MemRegion mr(startWord(), sizeInWords()); 192 return iterate(cl, mr); 193 } 194 195 #define check_mark(addr) \ 196 assert(_bmStartWord <= (addr) && (addr) < (_bmStartWord + _bmWordSize), \ 197 "outside underlying space?"); \ 198 assert(G1CollectedHeap::heap()->is_in_exact(addr), \ 199 err_msg("Trying to access not available bitmap "PTR_FORMAT \ 200 " corresponding to "PTR_FORMAT" (%u)", \ 201 p2i(this), p2i(addr), G1CollectedHeap::heap()->addr_to_region(addr))); 202 203 inline void CMBitMap::mark(HeapWord* addr) { 204 check_mark(addr); 205 _bm.set_bit(heapWordToOffset(addr)); 206 } 207 208 inline void CMBitMap::clear(HeapWord* addr) { 209 check_mark(addr); 210 _bm.clear_bit(heapWordToOffset(addr)); 211 } 212 213 inline bool CMBitMap::parMark(HeapWord* addr) { 214 check_mark(addr); 215 return _bm.par_set_bit(heapWordToOffset(addr)); 216 } 217 218 inline bool CMBitMap::parClear(HeapWord* addr) { 219 check_mark(addr); 220 return _bm.par_clear_bit(heapWordToOffset(addr)); 221 } 222 223 #undef check_mark 224 225 inline void CMTask::push(oop obj) { 226 HeapWord* objAddr = (HeapWord*) obj; 227 assert(_g1h->is_in_g1_reserved(objAddr), "invariant"); 228 assert(!_g1h->is_on_master_free_list( 229 _g1h->heap_region_containing((HeapWord*) objAddr)), "invariant"); 230 assert(!_g1h->is_obj_ill(obj), "invariant"); 231 assert(_nextMarkBitMap->isMarked(objAddr), "invariant"); 232 233 if (_cm->verbose_high()) { 234 gclog_or_tty->print_cr("[%u] pushing " PTR_FORMAT, _worker_id, p2i((void*) obj)); 235 } 236 237 if (!_task_queue->push(obj)) { 238 // The local task queue looks full. We need to push some entries 239 // to the global stack. 240 241 if (_cm->verbose_medium()) { 242 gclog_or_tty->print_cr("[%u] task queue overflow, " 243 "moving entries to the global stack", 244 _worker_id); 245 } 246 move_entries_to_global_stack(); 247 248 // this should succeed since, even if we overflow the global 249 // stack, we should have definitely removed some entries from the 250 // local queue. So, there must be space on it. 251 bool success = _task_queue->push(obj); 252 assert(success, "invariant"); 253 } 254 255 statsOnly( int tmp_size = _task_queue->size(); 256 if (tmp_size > _local_max_size) { 257 _local_max_size = tmp_size; 258 } 259 ++_local_pushes ); 260 } 261 262 inline bool CMTask::is_below_finger(oop obj, HeapWord* global_finger) const { 263 // If obj is above the global finger, then the mark bitmap scan 264 // will find it later, and no push is needed. Similarly, if we have 265 // a current region and obj is between the local finger and the 266 // end of the current region, then no push is needed. The tradeoff 267 // of checking both vs only checking the global finger is that the 268 // local check will be more accurate and so result in fewer pushes, 269 // but may also be a little slower. 270 HeapWord* objAddr = (HeapWord*)obj; 271 if (_finger != NULL) { 272 // We have a current region. 273 274 // Finger and region values are all NULL or all non-NULL. We 275 // use _finger to check since we immediately use its value. 276 assert(_curr_region != NULL, "invariant"); 277 assert(_region_limit != NULL, "invariant"); 278 assert(_region_limit <= global_finger, "invariant"); 279 280 // True if obj is less than the local finger, or is between 281 // the region limit and the global finger. 282 if (objAddr < _finger) { 283 return true; 284 } else if (objAddr < _region_limit) { 285 return false; 286 } // Else check global finger. 287 } 288 // Check global finger. 289 return objAddr < global_finger; 290 } 291 292 inline void CMTask::make_reference_grey(oop obj, HeapRegion* hr) { 293 if (_cm->par_mark_and_count(obj, hr, _marked_bytes_array, _card_bm)) { 294 295 if (_cm->verbose_high()) { 296 gclog_or_tty->print_cr("[%u] marked object " PTR_FORMAT, 297 _worker_id, p2i(obj)); 298 } 299 300 // No OrderAccess:store_load() is needed. It is implicit in the 301 // CAS done in CMBitMap::parMark() call in the routine above. 302 HeapWord* global_finger = _cm->finger(); 303 304 // We only need to push a newly grey object on the mark 305 // stack if it is in a section of memory the mark bitmap 306 // scan has already examined. Mark bitmap scanning 307 // maintains progress "fingers" for determining that. 308 // 309 // Notice that the global finger might be moving forward 310 // concurrently. This is not a problem. In the worst case, we 311 // mark the object while it is above the global finger and, by 312 // the time we read the global finger, it has moved forward 313 // past this object. In this case, the object will probably 314 // be visited when a task is scanning the region and will also 315 // be pushed on the stack. So, some duplicate work, but no 316 // correctness problems. 317 if (is_below_finger(obj, global_finger)) { 318 if (obj->is_typeArray()) { 319 // Immediately process arrays of primitive types, rather 320 // than pushing on the mark stack. This keeps us from 321 // adding humongous objects to the mark stack that might 322 // be reclaimed before the entry is processed - see 323 // selection of candidates for eager reclaim of humongous 324 // objects. The cost of the additional type test is 325 // mitigated by avoiding a trip through the mark stack, 326 // by only doing a bookkeeping update and avoiding the 327 // actual scan of the object - a typeArray contains no 328 // references, and the metadata is built-in. 329 process_grey_object<false>(obj); 330 } else { 331 if (_cm->verbose_high()) { 332 gclog_or_tty->print_cr("[%u] below a finger (local: " PTR_FORMAT 333 ", global: " PTR_FORMAT ") pushing " 334 PTR_FORMAT " on mark stack", 335 _worker_id, p2i(_finger), 336 p2i(global_finger), p2i(obj)); 337 } 338 push(obj); 339 } 340 } 341 } 342 } 343 344 inline void CMTask::deal_with_reference(oop obj) { 345 if (_cm->verbose_high()) { 346 gclog_or_tty->print_cr("[%u] we're dealing with reference = "PTR_FORMAT, 347 _worker_id, p2i((void*) obj)); 348 } 349 350 increment_refs_reached(); 351 352 HeapWord* objAddr = (HeapWord*) obj; 353 assert(obj->is_oop_or_null(true /* ignore mark word */), "Error"); 354 if (_g1h->is_in_g1_reserved(objAddr)) { 355 assert(obj != NULL, "null check is implicit"); 356 if (!_nextMarkBitMap->isMarked(objAddr)) { 357 // Only get the containing region if the object is not marked on the 358 // bitmap (otherwise, it's a waste of time since we won't do 359 // anything with it). 360 HeapRegion* hr = _g1h->heap_region_containing_raw(obj); 361 if (!hr->obj_allocated_since_next_marking(obj)) { 362 make_reference_grey(obj, hr); 363 } 364 } 365 } 366 } 367 368 inline void ConcurrentMark::markPrev(oop p) { 369 assert(!_prevMarkBitMap->isMarked((HeapWord*) p), "sanity"); 370 // Note we are overriding the read-only view of the prev map here, via 371 // the cast. 372 ((CMBitMap*)_prevMarkBitMap)->mark((HeapWord*) p); 373 } 374 375 inline void ConcurrentMark::grayRoot(oop obj, size_t word_size, 376 uint worker_id, HeapRegion* hr) { 377 assert(obj != NULL, "pre-condition"); 378 HeapWord* addr = (HeapWord*) obj; 379 if (hr == NULL) { 380 hr = _g1h->heap_region_containing_raw(addr); 381 } else { 382 assert(hr->is_in(addr), "pre-condition"); 383 } 384 assert(hr != NULL, "sanity"); 385 // Given that we're looking for a region that contains an object 386 // header it's impossible to get back a HC region. 387 assert(!hr->continuesHumongous(), "sanity"); 388 389 // We cannot assert that word_size == obj->size() given that obj 390 // might not be in a consistent state (another thread might be in 391 // the process of copying it). So the best thing we can do is to 392 // assert that word_size is under an upper bound which is its 393 // containing region's capacity. 394 assert(word_size * HeapWordSize <= hr->capacity(), 395 err_msg("size: "SIZE_FORMAT" capacity: "SIZE_FORMAT" "HR_FORMAT, 396 word_size * HeapWordSize, hr->capacity(), 397 HR_FORMAT_PARAMS(hr))); 398 399 if (addr < hr->next_top_at_mark_start()) { 400 if (!_nextMarkBitMap->isMarked(addr)) { 401 par_mark_and_count(obj, word_size, hr, worker_id); 402 } 403 } 404 } 405 406 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_CONCURRENTMARK_INLINE_HPP