1 /* 2 * Copyright (c) 2000, 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 #include "precompiled.hpp" 26 #include "gc/shared/cardTableModRefBS.inline.hpp" 27 #include "gc/shared/cardTableRS.hpp" 28 #include "gc/shared/collectedHeap.hpp" 29 #include "gc/shared/genCollectedHeap.hpp" 30 #include "gc/shared/space.hpp" 31 #include "gc/shared/space.inline.hpp" 32 #include "memory/allocation.inline.hpp" 33 #include "memory/universe.hpp" 34 #include "memory/virtualspace.hpp" 35 #include "runtime/java.hpp" 36 #include "runtime/mutexLocker.hpp" 37 #include "services/memTracker.hpp" 38 #include "utilities/macros.hpp" 39 #ifdef COMPILER1 40 #include "c1/c1_LIR.hpp" 41 #include "c1/c1_LIRGenerator.hpp" 42 #endif 43 44 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and 45 // enumerate ref fields that have been modified (since the last 46 // enumeration.) 47 48 size_t CardTableModRefBS::compute_byte_map_size() 49 { 50 assert(_guard_index == cards_required(_whole_heap.word_size()) - 1, 51 "uninitialized, check declaration order"); 52 assert(_page_size != 0, "uninitialized, check declaration order"); 53 const size_t granularity = os::vm_allocation_granularity(); 54 return align_size_up(_guard_index + 1, MAX2(_page_size, granularity)); 55 } 56 57 CardTableModRefBS::CardTableModRefBS( 58 MemRegion whole_heap, 59 const BarrierSet::FakeRtti& fake_rtti) : 60 ModRefBarrierSet(fake_rtti.add_tag(BarrierSet::CardTableModRef)), 61 _whole_heap(whole_heap), 62 _guard_index(0), 63 _guard_region(), 64 _last_valid_index(0), 65 _page_size(os::vm_page_size()), 66 _byte_map_size(0), 67 _covered(NULL), 68 _committed(NULL), 69 _cur_covered_regions(0), 70 _byte_map(NULL), 71 byte_map_base(NULL), 72 // LNC functionality 73 _lowest_non_clean(NULL), 74 _lowest_non_clean_chunk_size(NULL), 75 _lowest_non_clean_base_chunk_index(NULL), 76 _last_LNC_resizing_collection(NULL) 77 { 78 assert((uintptr_t(_whole_heap.start()) & (card_size - 1)) == 0, "heap must start at card boundary"); 79 assert((uintptr_t(_whole_heap.end()) & (card_size - 1)) == 0, "heap must end at card boundary"); 80 81 assert(card_size <= 512, "card_size must be less than 512"); // why? 82 83 _covered = new MemRegion[_max_covered_regions]; 84 if (_covered == NULL) { 85 vm_exit_during_initialization("Could not allocate card table covered region set."); 86 } 87 } 88 89 void CardTableModRefBS::initialize() { 90 _guard_index = cards_required(_whole_heap.word_size()) - 1; 91 _last_valid_index = _guard_index - 1; 92 93 _byte_map_size = compute_byte_map_size(); 94 95 HeapWord* low_bound = _whole_heap.start(); 96 HeapWord* high_bound = _whole_heap.end(); 97 98 _cur_covered_regions = 0; 99 _committed = new MemRegion[_max_covered_regions]; 100 if (_committed == NULL) { 101 vm_exit_during_initialization("Could not allocate card table committed region set."); 102 } 103 104 const size_t rs_align = _page_size == (size_t) os::vm_page_size() ? 0 : 105 MAX2(_page_size, (size_t) os::vm_allocation_granularity()); 106 ReservedSpace heap_rs(_byte_map_size, rs_align, false); 107 108 MemTracker::record_virtual_memory_type((address)heap_rs.base(), mtGC); 109 110 os::trace_page_sizes("card table", _guard_index + 1, _guard_index + 1, 111 _page_size, heap_rs.base(), heap_rs.size()); 112 if (!heap_rs.is_reserved()) { 113 vm_exit_during_initialization("Could not reserve enough space for the " 114 "card marking array"); 115 } 116 117 // The assembler store_check code will do an unsigned shift of the oop, 118 // then add it to byte_map_base, i.e. 119 // 120 // _byte_map = byte_map_base + (uintptr_t(low_bound) >> card_shift) 121 _byte_map = (jbyte*) heap_rs.base(); 122 byte_map_base = _byte_map - (uintptr_t(low_bound) >> card_shift); 123 assert(byte_for(low_bound) == &_byte_map[0], "Checking start of map"); 124 assert(byte_for(high_bound-1) <= &_byte_map[_last_valid_index], "Checking end of map"); 125 126 jbyte* guard_card = &_byte_map[_guard_index]; 127 uintptr_t guard_page = align_size_down((uintptr_t)guard_card, _page_size); 128 _guard_region = MemRegion((HeapWord*)guard_page, _page_size); 129 os::commit_memory_or_exit((char*)guard_page, _page_size, _page_size, 130 !ExecMem, "card table last card"); 131 *guard_card = last_card; 132 133 _lowest_non_clean = 134 NEW_C_HEAP_ARRAY(CardArr, _max_covered_regions, mtGC); 135 _lowest_non_clean_chunk_size = 136 NEW_C_HEAP_ARRAY(size_t, _max_covered_regions, mtGC); 137 _lowest_non_clean_base_chunk_index = 138 NEW_C_HEAP_ARRAY(uintptr_t, _max_covered_regions, mtGC); 139 _last_LNC_resizing_collection = 140 NEW_C_HEAP_ARRAY(int, _max_covered_regions, mtGC); 141 if (_lowest_non_clean == NULL 142 || _lowest_non_clean_chunk_size == NULL 143 || _lowest_non_clean_base_chunk_index == NULL 144 || _last_LNC_resizing_collection == NULL) 145 vm_exit_during_initialization("couldn't allocate an LNC array."); 146 for (int i = 0; i < _max_covered_regions; i++) { 147 _lowest_non_clean[i] = NULL; 148 _lowest_non_clean_chunk_size[i] = 0; 149 _last_LNC_resizing_collection[i] = -1; 150 } 151 152 if (TraceCardTableModRefBS) { 153 gclog_or_tty->print_cr("CardTableModRefBS::CardTableModRefBS: "); 154 gclog_or_tty->print_cr(" " 155 " &_byte_map[0]: " INTPTR_FORMAT 156 " &_byte_map[_last_valid_index]: " INTPTR_FORMAT, 157 p2i(&_byte_map[0]), 158 p2i(&_byte_map[_last_valid_index])); 159 gclog_or_tty->print_cr(" " 160 " byte_map_base: " INTPTR_FORMAT, 161 p2i(byte_map_base)); 162 } 163 } 164 165 CardTableModRefBS::~CardTableModRefBS() { 166 if (_covered) { 167 delete[] _covered; 168 _covered = NULL; 169 } 170 if (_committed) { 171 delete[] _committed; 172 _committed = NULL; 173 } 174 if (_lowest_non_clean) { 175 FREE_C_HEAP_ARRAY(CardArr, _lowest_non_clean); 176 _lowest_non_clean = NULL; 177 } 178 if (_lowest_non_clean_chunk_size) { 179 FREE_C_HEAP_ARRAY(size_t, _lowest_non_clean_chunk_size); 180 _lowest_non_clean_chunk_size = NULL; 181 } 182 if (_lowest_non_clean_base_chunk_index) { 183 FREE_C_HEAP_ARRAY(uintptr_t, _lowest_non_clean_base_chunk_index); 184 _lowest_non_clean_base_chunk_index = NULL; 185 } 186 if (_last_LNC_resizing_collection) { 187 FREE_C_HEAP_ARRAY(int, _last_LNC_resizing_collection); 188 _last_LNC_resizing_collection = NULL; 189 } 190 } 191 192 int CardTableModRefBS::find_covering_region_by_base(HeapWord* base) { 193 int i; 194 for (i = 0; i < _cur_covered_regions; i++) { 195 if (_covered[i].start() == base) return i; 196 if (_covered[i].start() > base) break; 197 } 198 // If we didn't find it, create a new one. 199 assert(_cur_covered_regions < _max_covered_regions, 200 "too many covered regions"); 201 // Move the ones above up, to maintain sorted order. 202 for (int j = _cur_covered_regions; j > i; j--) { 203 _covered[j] = _covered[j-1]; 204 _committed[j] = _committed[j-1]; 205 } 206 int res = i; 207 _cur_covered_regions++; 208 _covered[res].set_start(base); 209 _covered[res].set_word_size(0); 210 jbyte* ct_start = byte_for(base); 211 uintptr_t ct_start_aligned = align_size_down((uintptr_t)ct_start, _page_size); 212 _committed[res].set_start((HeapWord*)ct_start_aligned); 213 _committed[res].set_word_size(0); 214 return res; 215 } 216 217 int CardTableModRefBS::find_covering_region_containing(HeapWord* addr) { 218 for (int i = 0; i < _cur_covered_regions; i++) { 219 if (_covered[i].contains(addr)) { 220 return i; 221 } 222 } 223 assert(0, "address outside of heap?"); 224 return -1; 225 } 226 227 HeapWord* CardTableModRefBS::largest_prev_committed_end(int ind) const { 228 HeapWord* max_end = NULL; 229 for (int j = 0; j < ind; j++) { 230 HeapWord* this_end = _committed[j].end(); 231 if (this_end > max_end) max_end = this_end; 232 } 233 return max_end; 234 } 235 236 MemRegion CardTableModRefBS::committed_unique_to_self(int self, 237 MemRegion mr) const { 238 MemRegion result = mr; 239 for (int r = 0; r < _cur_covered_regions; r += 1) { 240 if (r != self) { 241 result = result.minus(_committed[r]); 242 } 243 } 244 // Never include the guard page. 245 result = result.minus(_guard_region); 246 return result; 247 } 248 249 void CardTableModRefBS::resize_covered_region(MemRegion new_region) { 250 // We don't change the start of a region, only the end. 251 assert(_whole_heap.contains(new_region), 252 "attempt to cover area not in reserved area"); 253 debug_only(verify_guard();) 254 // collided is true if the expansion would push into another committed region 255 debug_only(bool collided = false;) 256 int const ind = find_covering_region_by_base(new_region.start()); 257 MemRegion const old_region = _covered[ind]; 258 assert(old_region.start() == new_region.start(), "just checking"); 259 if (new_region.word_size() != old_region.word_size()) { 260 // Commit new or uncommit old pages, if necessary. 261 MemRegion cur_committed = _committed[ind]; 262 // Extend the end of this _committed region 263 // to cover the end of any lower _committed regions. 264 // This forms overlapping regions, but never interior regions. 265 HeapWord* const max_prev_end = largest_prev_committed_end(ind); 266 if (max_prev_end > cur_committed.end()) { 267 cur_committed.set_end(max_prev_end); 268 } 269 // Align the end up to a page size (starts are already aligned). 270 jbyte* const new_end = byte_after(new_region.last()); 271 HeapWord* new_end_aligned = 272 (HeapWord*) align_size_up((uintptr_t)new_end, _page_size); 273 assert(new_end_aligned >= (HeapWord*) new_end, 274 "align up, but less"); 275 // Check the other regions (excludes "ind") to ensure that 276 // the new_end_aligned does not intrude onto the committed 277 // space of another region. 278 int ri = 0; 279 for (ri = ind + 1; ri < _cur_covered_regions; ri++) { 280 if (new_end_aligned > _committed[ri].start()) { 281 assert(new_end_aligned <= _committed[ri].end(), 282 "An earlier committed region can't cover a later committed region"); 283 // Any region containing the new end 284 // should start at or beyond the region found (ind) 285 // for the new end (committed regions are not expected to 286 // be proper subsets of other committed regions). 287 assert(_committed[ri].start() >= _committed[ind].start(), 288 "New end of committed region is inconsistent"); 289 new_end_aligned = _committed[ri].start(); 290 // new_end_aligned can be equal to the start of its 291 // committed region (i.e., of "ind") if a second 292 // region following "ind" also start at the same location 293 // as "ind". 294 assert(new_end_aligned >= _committed[ind].start(), 295 "New end of committed region is before start"); 296 debug_only(collided = true;) 297 // Should only collide with 1 region 298 break; 299 } 300 } 301 #ifdef ASSERT 302 for (++ri; ri < _cur_covered_regions; ri++) { 303 assert(!_committed[ri].contains(new_end_aligned), 304 "New end of committed region is in a second committed region"); 305 } 306 #endif 307 // The guard page is always committed and should not be committed over. 308 // "guarded" is used for assertion checking below and recalls the fact 309 // that the would-be end of the new committed region would have 310 // penetrated the guard page. 311 HeapWord* new_end_for_commit = new_end_aligned; 312 313 DEBUG_ONLY(bool guarded = false;) 314 if (new_end_for_commit > _guard_region.start()) { 315 new_end_for_commit = _guard_region.start(); 316 DEBUG_ONLY(guarded = true;) 317 } 318 319 if (new_end_for_commit > cur_committed.end()) { 320 // Must commit new pages. 321 MemRegion const new_committed = 322 MemRegion(cur_committed.end(), new_end_for_commit); 323 324 assert(!new_committed.is_empty(), "Region should not be empty here"); 325 os::commit_memory_or_exit((char*)new_committed.start(), 326 new_committed.byte_size(), _page_size, 327 !ExecMem, "card table expansion"); 328 // Use new_end_aligned (as opposed to new_end_for_commit) because 329 // the cur_committed region may include the guard region. 330 } else if (new_end_aligned < cur_committed.end()) { 331 // Must uncommit pages. 332 MemRegion const uncommit_region = 333 committed_unique_to_self(ind, MemRegion(new_end_aligned, 334 cur_committed.end())); 335 if (!uncommit_region.is_empty()) { 336 // It is not safe to uncommit cards if the boundary between 337 // the generations is moving. A shrink can uncommit cards 338 // owned by generation A but being used by generation B. 339 if (!UseAdaptiveGCBoundary) { 340 if (!os::uncommit_memory((char*)uncommit_region.start(), 341 uncommit_region.byte_size())) { 342 assert(false, "Card table contraction failed"); 343 // The call failed so don't change the end of the 344 // committed region. This is better than taking the 345 // VM down. 346 new_end_aligned = _committed[ind].end(); 347 } 348 } else { 349 new_end_aligned = _committed[ind].end(); 350 } 351 } 352 } 353 // In any case, we can reset the end of the current committed entry. 354 _committed[ind].set_end(new_end_aligned); 355 356 #ifdef ASSERT 357 // Check that the last card in the new region is committed according 358 // to the tables. 359 bool covered = false; 360 for (int cr = 0; cr < _cur_covered_regions; cr++) { 361 if (_committed[cr].contains(new_end - 1)) { 362 covered = true; 363 break; 364 } 365 } 366 assert(covered, "Card for end of new region not committed"); 367 #endif 368 369 // The default of 0 is not necessarily clean cards. 370 jbyte* entry; 371 if (old_region.last() < _whole_heap.start()) { 372 entry = byte_for(_whole_heap.start()); 373 } else { 374 entry = byte_after(old_region.last()); 375 } 376 assert(index_for(new_region.last()) < _guard_index, 377 "The guard card will be overwritten"); 378 // This line commented out cleans the newly expanded region and 379 // not the aligned up expanded region. 380 // jbyte* const end = byte_after(new_region.last()); 381 jbyte* const end = (jbyte*) new_end_for_commit; 382 assert((end >= byte_after(new_region.last())) || collided || guarded, 383 "Expect to be beyond new region unless impacting another region"); 384 // do nothing if we resized downward. 385 #ifdef ASSERT 386 for (int ri = 0; ri < _cur_covered_regions; ri++) { 387 if (ri != ind) { 388 // The end of the new committed region should not 389 // be in any existing region unless it matches 390 // the start of the next region. 391 assert(!_committed[ri].contains(end) || 392 (_committed[ri].start() == (HeapWord*) end), 393 "Overlapping committed regions"); 394 } 395 } 396 #endif 397 if (entry < end) { 398 memset(entry, clean_card, pointer_delta(end, entry, sizeof(jbyte))); 399 } 400 } 401 // In any case, the covered size changes. 402 _covered[ind].set_word_size(new_region.word_size()); 403 if (TraceCardTableModRefBS) { 404 gclog_or_tty->print_cr("CardTableModRefBS::resize_covered_region: "); 405 gclog_or_tty->print_cr(" " 406 " _covered[%d].start(): " INTPTR_FORMAT 407 " _covered[%d].last(): " INTPTR_FORMAT, 408 ind, p2i(_covered[ind].start()), 409 ind, p2i(_covered[ind].last())); 410 gclog_or_tty->print_cr(" " 411 " _committed[%d].start(): " INTPTR_FORMAT 412 " _committed[%d].last(): " INTPTR_FORMAT, 413 ind, p2i(_committed[ind].start()), 414 ind, p2i(_committed[ind].last())); 415 gclog_or_tty->print_cr(" " 416 " byte_for(start): " INTPTR_FORMAT 417 " byte_for(last): " INTPTR_FORMAT, 418 p2i(byte_for(_covered[ind].start())), 419 p2i(byte_for(_covered[ind].last()))); 420 gclog_or_tty->print_cr(" " 421 " addr_for(start): " INTPTR_FORMAT 422 " addr_for(last): " INTPTR_FORMAT, 423 p2i(addr_for((jbyte*) _committed[ind].start())), 424 p2i(addr_for((jbyte*) _committed[ind].last()))); 425 } 426 // Touch the last card of the covered region to show that it 427 // is committed (or SEGV). 428 debug_only((void) (*byte_for(_covered[ind].last()));) 429 debug_only(verify_guard();) 430 } 431 432 // Note that these versions are precise! The scanning code has to handle the 433 // fact that the write barrier may be either precise or imprecise. 434 435 void CardTableModRefBS::write_ref_field_work(void* field, oop newVal, bool release) { 436 inline_write_ref_field(field, newVal, release); 437 } 438 439 440 void CardTableModRefBS::non_clean_card_iterate_possibly_parallel(Space* sp, 441 MemRegion mr, 442 OopsInGenClosure* cl, 443 CardTableRS* ct) { 444 if (!mr.is_empty()) { 445 // Caller (process_roots()) claims that all GC threads 446 // execute this call. With UseDynamicNumberOfGCThreads now all 447 // active GC threads execute this call. The number of active GC 448 // threads needs to be passed to par_non_clean_card_iterate_work() 449 // to get proper partitioning and termination. 450 // 451 // This is an example of where n_par_threads() is used instead 452 // of workers()->active_workers(). n_par_threads can be set to 0 to 453 // turn off parallelism. For example when this code is called as 454 // part of verification during root processing then n_par_threads() 455 // may have been set to 0. active_workers is not overloaded with 456 // the meaning that it is a switch to disable parallelism and so keeps 457 // the meaning of the number of active gc workers. If parallelism has 458 // not been shut off by setting n_par_threads to 0, then n_par_threads 459 // should be equal to active_workers. When a different mechanism for 460 // shutting off parallelism is used, then active_workers can be used in 461 // place of n_par_threads. 462 int n_threads = GenCollectedHeap::heap()->n_par_threads(); 463 bool is_par = n_threads > 0; 464 if (is_par) { 465 #if INCLUDE_ALL_GCS 466 assert(GenCollectedHeap::heap()->n_par_threads() == 467 GenCollectedHeap::heap()->workers()->active_workers(), "Mismatch"); 468 non_clean_card_iterate_parallel_work(sp, mr, cl, ct, n_threads); 469 #else // INCLUDE_ALL_GCS 470 fatal("Parallel gc not supported here."); 471 #endif // INCLUDE_ALL_GCS 472 } else { 473 // clear_cl finds contiguous dirty ranges of cards to process and clear. 474 475 DirtyCardToOopClosure* dcto_cl = sp->new_dcto_cl(cl, precision(), cl->gen_boundary()); 476 ClearNoncleanCardWrapper clear_cl(dcto_cl, ct); 477 478 clear_cl.do_MemRegion(mr); 479 } 480 } 481 } 482 483 void CardTableModRefBS::dirty_MemRegion(MemRegion mr) { 484 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start"); 485 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" ); 486 jbyte* cur = byte_for(mr.start()); 487 jbyte* last = byte_after(mr.last()); 488 while (cur < last) { 489 *cur = dirty_card; 490 cur++; 491 } 492 } 493 494 void CardTableModRefBS::invalidate(MemRegion mr, bool whole_heap) { 495 assert((HeapWord*)align_size_down((uintptr_t)mr.start(), HeapWordSize) == mr.start(), "Unaligned start"); 496 assert((HeapWord*)align_size_up ((uintptr_t)mr.end(), HeapWordSize) == mr.end(), "Unaligned end" ); 497 for (int i = 0; i < _cur_covered_regions; i++) { 498 MemRegion mri = mr.intersection(_covered[i]); 499 if (!mri.is_empty()) dirty_MemRegion(mri); 500 } 501 } 502 503 void CardTableModRefBS::clear_MemRegion(MemRegion mr) { 504 // Be conservative: only clean cards entirely contained within the 505 // region. 506 jbyte* cur; 507 if (mr.start() == _whole_heap.start()) { 508 cur = byte_for(mr.start()); 509 } else { 510 assert(mr.start() > _whole_heap.start(), "mr is not covered."); 511 cur = byte_after(mr.start() - 1); 512 } 513 jbyte* last = byte_after(mr.last()); 514 memset(cur, clean_card, pointer_delta(last, cur, sizeof(jbyte))); 515 } 516 517 void CardTableModRefBS::clear(MemRegion mr) { 518 for (int i = 0; i < _cur_covered_regions; i++) { 519 MemRegion mri = mr.intersection(_covered[i]); 520 if (!mri.is_empty()) clear_MemRegion(mri); 521 } 522 } 523 524 void CardTableModRefBS::dirty(MemRegion mr) { 525 jbyte* first = byte_for(mr.start()); 526 jbyte* last = byte_after(mr.last()); 527 memset(first, dirty_card, last-first); 528 } 529 530 // Unlike several other card table methods, dirty_card_iterate() 531 // iterates over dirty cards ranges in increasing address order. 532 void CardTableModRefBS::dirty_card_iterate(MemRegion mr, 533 MemRegionClosure* cl) { 534 for (int i = 0; i < _cur_covered_regions; i++) { 535 MemRegion mri = mr.intersection(_covered[i]); 536 if (!mri.is_empty()) { 537 jbyte *cur_entry, *next_entry, *limit; 538 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last()); 539 cur_entry <= limit; 540 cur_entry = next_entry) { 541 next_entry = cur_entry + 1; 542 if (*cur_entry == dirty_card) { 543 size_t dirty_cards; 544 // Accumulate maximal dirty card range, starting at cur_entry 545 for (dirty_cards = 1; 546 next_entry <= limit && *next_entry == dirty_card; 547 dirty_cards++, next_entry++); 548 MemRegion cur_cards(addr_for(cur_entry), 549 dirty_cards*card_size_in_words); 550 cl->do_MemRegion(cur_cards); 551 } 552 } 553 } 554 } 555 } 556 557 MemRegion CardTableModRefBS::dirty_card_range_after_reset(MemRegion mr, 558 bool reset, 559 int reset_val) { 560 for (int i = 0; i < _cur_covered_regions; i++) { 561 MemRegion mri = mr.intersection(_covered[i]); 562 if (!mri.is_empty()) { 563 jbyte* cur_entry, *next_entry, *limit; 564 for (cur_entry = byte_for(mri.start()), limit = byte_for(mri.last()); 565 cur_entry <= limit; 566 cur_entry = next_entry) { 567 next_entry = cur_entry + 1; 568 if (*cur_entry == dirty_card) { 569 size_t dirty_cards; 570 // Accumulate maximal dirty card range, starting at cur_entry 571 for (dirty_cards = 1; 572 next_entry <= limit && *next_entry == dirty_card; 573 dirty_cards++, next_entry++); 574 MemRegion cur_cards(addr_for(cur_entry), 575 dirty_cards*card_size_in_words); 576 if (reset) { 577 for (size_t i = 0; i < dirty_cards; i++) { 578 cur_entry[i] = reset_val; 579 } 580 } 581 return cur_cards; 582 } 583 } 584 } 585 } 586 return MemRegion(mr.end(), mr.end()); 587 } 588 589 uintx CardTableModRefBS::ct_max_alignment_constraint() { 590 return card_size * os::vm_page_size(); 591 } 592 593 void CardTableModRefBS::verify_guard() { 594 // For product build verification 595 guarantee(_byte_map[_guard_index] == last_card, 596 "card table guard has been modified"); 597 } 598 599 void CardTableModRefBS::verify() { 600 verify_guard(); 601 } 602 603 #ifndef PRODUCT 604 void CardTableModRefBS::verify_region(MemRegion mr, 605 jbyte val, bool val_equals) { 606 jbyte* start = byte_for(mr.start()); 607 jbyte* end = byte_for(mr.last()); 608 bool failures = false; 609 for (jbyte* curr = start; curr <= end; ++curr) { 610 jbyte curr_val = *curr; 611 bool failed = (val_equals) ? (curr_val != val) : (curr_val == val); 612 if (failed) { 613 if (!failures) { 614 tty->cr(); 615 tty->print_cr("== CT verification failed: [" INTPTR_FORMAT "," INTPTR_FORMAT "]", p2i(start), p2i(end)); 616 tty->print_cr("== %sexpecting value: %d", 617 (val_equals) ? "" : "not ", val); 618 failures = true; 619 } 620 tty->print_cr("== card " PTR_FORMAT " [" PTR_FORMAT "," PTR_FORMAT "], " 621 "val: %d", p2i(curr), p2i(addr_for(curr)), 622 p2i((HeapWord*) (((size_t) addr_for(curr)) + card_size)), 623 (int) curr_val); 624 } 625 } 626 guarantee(!failures, "there should not have been any failures"); 627 } 628 629 void CardTableModRefBS::verify_not_dirty_region(MemRegion mr) { 630 verify_region(mr, dirty_card, false /* val_equals */); 631 } 632 633 void CardTableModRefBS::verify_dirty_region(MemRegion mr) { 634 verify_region(mr, dirty_card, true /* val_equals */); 635 } 636 #endif 637 638 void CardTableModRefBS::print_on(outputStream* st) const { 639 st->print_cr("Card table byte_map: [" INTPTR_FORMAT "," INTPTR_FORMAT "] byte_map_base: " INTPTR_FORMAT, 640 p2i(_byte_map), p2i(_byte_map + _byte_map_size), p2i(byte_map_base)); 641 } 642 643 bool CardTableModRefBSForCTRS::card_will_be_scanned(jbyte cv) { 644 return 645 CardTableModRefBS::card_will_be_scanned(cv) || 646 _rs->is_prev_nonclean_card_val(cv); 647 }; 648 649 bool CardTableModRefBSForCTRS::card_may_have_been_dirty(jbyte cv) { 650 return 651 cv != clean_card && 652 (CardTableModRefBS::card_may_have_been_dirty(cv) || 653 CardTableRS::youngergen_may_have_been_dirty(cv)); 654 };