1 /* 2 * Copyright (c) 2023, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved. 4 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved. 5 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 6 * 7 * This code is free software; you can redistribute it and/or modify it 8 * under the terms of the GNU General Public License version 2 only, as 9 * published by the Free Software Foundation. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 * 25 */ 26 27 #include "precompiled.hpp" 28 #include "gc/shared/cardTable.hpp" 29 #include "gc/shared/space.inline.hpp" 30 #include "gc/shared/tlab_globals.hpp" 31 #include "gc/shenandoah/shenandoahCardTable.hpp" 32 #include "gc/shenandoah/shenandoahFreeSet.hpp" 33 #include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp" 34 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 35 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 36 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 37 #include "gc/shenandoah/shenandoahOldGeneration.hpp" 38 #include "gc/shenandoah/shenandoahGeneration.hpp" 39 #include "gc/shenandoah/shenandoahYoungGeneration.hpp" 40 #include "gc/shenandoah/shenandoahScanRemembered.inline.hpp" 41 #include "jfr/jfrEvents.hpp" 42 #include "memory/allocation.hpp" 43 #include "memory/iterator.inline.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "memory/universe.hpp" 46 #include "oops/oop.inline.hpp" 47 #include "runtime/atomic.hpp" 48 #include "runtime/globals_extension.hpp" 49 #include "runtime/java.hpp" 50 #include "runtime/mutexLocker.hpp" 51 #include "runtime/os.hpp" 52 #include "runtime/safepoint.hpp" 53 #include "utilities/powerOfTwo.hpp" 54 55 56 size_t ShenandoahHeapRegion::RegionCount = 0; 57 size_t ShenandoahHeapRegion::RegionSizeBytes = 0; 58 size_t ShenandoahHeapRegion::RegionSizeWords = 0; 59 size_t ShenandoahHeapRegion::RegionSizeBytesShift = 0; 60 size_t ShenandoahHeapRegion::RegionSizeWordsShift = 0; 61 size_t ShenandoahHeapRegion::RegionSizeBytesMask = 0; 62 size_t ShenandoahHeapRegion::RegionSizeWordsMask = 0; 63 size_t ShenandoahHeapRegion::HumongousThresholdBytes = 0; 64 size_t ShenandoahHeapRegion::HumongousThresholdWords = 0; 65 size_t ShenandoahHeapRegion::MaxTLABSizeBytes = 0; 66 size_t ShenandoahHeapRegion::MaxTLABSizeWords = 0; 67 68 ShenandoahHeapRegion::ShenandoahHeapRegion(HeapWord* start, size_t index, bool committed) : 69 _index(index), 70 _bottom(start), 71 _end(start + RegionSizeWords), 72 _new_top(nullptr), 73 _empty_time(os::elapsedTime()), 74 _top_before_promoted(nullptr), 75 _state(committed ? _empty_committed : _empty_uncommitted), 76 _top(start), 77 _tlab_allocs(0), 78 _gclab_allocs(0), 79 _plab_allocs(0), 80 _live_data(0), 81 _critical_pins(0), 82 _update_watermark(start), 83 _age(0) 84 #ifdef SHENANDOAH_CENSUS_NOISE 85 , _youth(0) 86 #endif // SHENANDOAH_CENSUS_NOISE 87 { 88 89 assert(Universe::on_page_boundary(_bottom) && Universe::on_page_boundary(_end), 90 "invalid space boundaries"); 91 if (ZapUnusedHeapArea && committed) { 92 SpaceMangler::mangle_region(MemRegion(_bottom, _end)); 93 } 94 } 95 96 void ShenandoahHeapRegion::report_illegal_transition(const char *method) { 97 stringStream ss; 98 ss.print("Illegal region state transition from \"%s\", at %s\n ", region_state_to_string(_state), method); 99 print_on(&ss); 100 fatal("%s", ss.freeze()); 101 } 102 103 void ShenandoahHeapRegion::make_regular_allocation(ShenandoahAffiliation affiliation) { 104 shenandoah_assert_heaplocked(); 105 reset_age(); 106 switch (_state) { 107 case _empty_uncommitted: 108 do_commit(); 109 case _empty_committed: 110 assert(this->affiliation() == affiliation, "Region affiliation should already be established"); 111 set_state(_regular); 112 case _regular: 113 case _pinned: 114 return; 115 default: 116 report_illegal_transition("regular allocation"); 117 } 118 } 119 120 // Change affiliation to YOUNG_GENERATION if _state is not _pinned_cset, _regular, or _pinned. This implements 121 // behavior previously performed as a side effect of make_regular_bypass(). 122 void ShenandoahHeapRegion::make_young_maybe() { 123 shenandoah_assert_heaplocked(); 124 switch (_state) { 125 case _empty_uncommitted: 126 case _empty_committed: 127 case _cset: 128 case _humongous_start: 129 case _humongous_cont: 130 if (affiliation() != YOUNG_GENERATION) { 131 if (is_old()) { 132 ShenandoahHeap::heap()->old_generation()->decrement_affiliated_region_count(); 133 } 134 set_affiliation(YOUNG_GENERATION); 135 ShenandoahHeap::heap()->young_generation()->increment_affiliated_region_count(); 136 } 137 return; 138 case _pinned_cset: 139 case _regular: 140 case _pinned: 141 return; 142 default: 143 assert(false, "Unexpected _state in make_young_maybe"); 144 } 145 } 146 147 void ShenandoahHeapRegion::make_regular_bypass() { 148 shenandoah_assert_heaplocked(); 149 assert (ShenandoahHeap::heap()->is_full_gc_in_progress() || ShenandoahHeap::heap()->is_degenerated_gc_in_progress(), 150 "only for full or degen GC"); 151 reset_age(); 152 switch (_state) { 153 case _empty_uncommitted: 154 do_commit(); 155 case _empty_committed: 156 case _cset: 157 case _humongous_start: 158 case _humongous_cont: 159 set_state(_regular); 160 return; 161 case _pinned_cset: 162 set_state(_pinned); 163 return; 164 case _regular: 165 case _pinned: 166 return; 167 default: 168 report_illegal_transition("regular bypass"); 169 } 170 } 171 172 void ShenandoahHeapRegion::make_humongous_start() { 173 shenandoah_assert_heaplocked(); 174 reset_age(); 175 switch (_state) { 176 case _empty_uncommitted: 177 do_commit(); 178 case _empty_committed: 179 set_state(_humongous_start); 180 return; 181 default: 182 report_illegal_transition("humongous start allocation"); 183 } 184 } 185 186 void ShenandoahHeapRegion::make_humongous_start_bypass(ShenandoahAffiliation affiliation) { 187 shenandoah_assert_heaplocked(); 188 assert (ShenandoahHeap::heap()->is_full_gc_in_progress(), "only for full GC"); 189 // Don't bother to account for affiliated regions during Full GC. We recompute totals at end. 190 set_affiliation(affiliation); 191 reset_age(); 192 switch (_state) { 193 case _empty_committed: 194 case _regular: 195 case _humongous_start: 196 case _humongous_cont: 197 set_state(_humongous_start); 198 return; 199 default: 200 report_illegal_transition("humongous start bypass"); 201 } 202 } 203 204 void ShenandoahHeapRegion::make_humongous_cont() { 205 shenandoah_assert_heaplocked(); 206 reset_age(); 207 switch (_state) { 208 case _empty_uncommitted: 209 do_commit(); 210 case _empty_committed: 211 set_state(_humongous_cont); 212 return; 213 default: 214 report_illegal_transition("humongous continuation allocation"); 215 } 216 } 217 218 void ShenandoahHeapRegion::make_humongous_cont_bypass(ShenandoahAffiliation affiliation) { 219 shenandoah_assert_heaplocked(); 220 assert (ShenandoahHeap::heap()->is_full_gc_in_progress(), "only for full GC"); 221 set_affiliation(affiliation); 222 // Don't bother to account for affiliated regions during Full GC. We recompute totals at end. 223 reset_age(); 224 switch (_state) { 225 case _empty_committed: 226 case _regular: 227 case _humongous_start: 228 case _humongous_cont: 229 set_state(_humongous_cont); 230 return; 231 default: 232 report_illegal_transition("humongous continuation bypass"); 233 } 234 } 235 236 void ShenandoahHeapRegion::make_pinned() { 237 shenandoah_assert_heaplocked(); 238 assert(pin_count() > 0, "Should have pins: " SIZE_FORMAT, pin_count()); 239 240 switch (_state) { 241 case _regular: 242 set_state(_pinned); 243 case _pinned_cset: 244 case _pinned: 245 return; 246 case _humongous_start: 247 set_state(_pinned_humongous_start); 248 case _pinned_humongous_start: 249 return; 250 case _cset: 251 _state = _pinned_cset; 252 return; 253 default: 254 report_illegal_transition("pinning"); 255 } 256 } 257 258 void ShenandoahHeapRegion::make_unpinned() { 259 shenandoah_assert_heaplocked(); 260 assert(pin_count() == 0, "Should not have pins: " SIZE_FORMAT, pin_count()); 261 262 switch (_state) { 263 case _pinned: 264 assert(is_affiliated(), "Pinned region should be affiliated"); 265 set_state(_regular); 266 return; 267 case _regular: 268 case _humongous_start: 269 return; 270 case _pinned_cset: 271 set_state(_cset); 272 return; 273 case _pinned_humongous_start: 274 set_state(_humongous_start); 275 return; 276 default: 277 report_illegal_transition("unpinning"); 278 } 279 } 280 281 void ShenandoahHeapRegion::make_cset() { 282 shenandoah_assert_heaplocked(); 283 // Leave age untouched. We need to consult the age when we are deciding whether to promote evacuated objects. 284 switch (_state) { 285 case _regular: 286 set_state(_cset); 287 case _cset: 288 return; 289 default: 290 report_illegal_transition("cset"); 291 } 292 } 293 294 void ShenandoahHeapRegion::make_trash() { 295 shenandoah_assert_heaplocked(); 296 reset_age(); 297 switch (_state) { 298 case _humongous_start: 299 case _humongous_cont: 300 { 301 // Reclaiming humongous regions and reclaim humongous waste. When this region is eventually recycled, we'll reclaim 302 // its used memory. At recycle time, we no longer recognize this as a humongous region. 303 decrement_humongous_waste(); 304 } 305 case _cset: 306 // Reclaiming cset regions 307 case _regular: 308 // Immediate region reclaim 309 set_state(_trash); 310 return; 311 default: 312 report_illegal_transition("trashing"); 313 } 314 } 315 316 void ShenandoahHeapRegion::make_trash_immediate() { 317 make_trash(); 318 319 // On this path, we know there are no marked objects in the region, 320 // tell marking context about it to bypass bitmap resets. 321 assert(ShenandoahHeap::heap()->active_generation()->is_mark_complete(), "Marking should be complete here."); 322 ShenandoahHeap::heap()->marking_context()->reset_top_bitmap(this); 323 } 324 325 void ShenandoahHeapRegion::make_empty() { 326 shenandoah_assert_heaplocked(); 327 reset_age(); 328 CENSUS_NOISE(clear_youth();) 329 switch (_state) { 330 case _trash: 331 set_state(_empty_committed); 332 _empty_time = os::elapsedTime(); 333 return; 334 default: 335 report_illegal_transition("emptying"); 336 } 337 } 338 339 void ShenandoahHeapRegion::make_uncommitted() { 340 shenandoah_assert_heaplocked(); 341 switch (_state) { 342 case _empty_committed: 343 do_uncommit(); 344 set_state(_empty_uncommitted); 345 return; 346 default: 347 report_illegal_transition("uncommiting"); 348 } 349 } 350 351 void ShenandoahHeapRegion::make_committed_bypass() { 352 shenandoah_assert_heaplocked(); 353 assert (ShenandoahHeap::heap()->is_full_gc_in_progress(), "only for full GC"); 354 355 switch (_state) { 356 case _empty_uncommitted: 357 do_commit(); 358 set_state(_empty_committed); 359 return; 360 default: 361 report_illegal_transition("commit bypass"); 362 } 363 } 364 365 void ShenandoahHeapRegion::reset_alloc_metadata() { 366 _tlab_allocs = 0; 367 _gclab_allocs = 0; 368 _plab_allocs = 0; 369 } 370 371 size_t ShenandoahHeapRegion::get_shared_allocs() const { 372 return used() - (_tlab_allocs + _gclab_allocs + _plab_allocs) * HeapWordSize; 373 } 374 375 size_t ShenandoahHeapRegion::get_tlab_allocs() const { 376 return _tlab_allocs * HeapWordSize; 377 } 378 379 size_t ShenandoahHeapRegion::get_gclab_allocs() const { 380 return _gclab_allocs * HeapWordSize; 381 } 382 383 size_t ShenandoahHeapRegion::get_plab_allocs() const { 384 return _plab_allocs * HeapWordSize; 385 } 386 387 void ShenandoahHeapRegion::set_live_data(size_t s) { 388 assert(Thread::current()->is_VM_thread(), "by VM thread"); 389 _live_data = (s >> LogHeapWordSize); 390 } 391 392 void ShenandoahHeapRegion::print_on(outputStream* st) const { 393 st->print("|"); 394 st->print(SIZE_FORMAT_W(5), this->_index); 395 396 switch (_state) { 397 case _empty_uncommitted: 398 st->print("|EU "); 399 break; 400 case _empty_committed: 401 st->print("|EC "); 402 break; 403 case _regular: 404 st->print("|R "); 405 break; 406 case _humongous_start: 407 st->print("|H "); 408 break; 409 case _pinned_humongous_start: 410 st->print("|HP "); 411 break; 412 case _humongous_cont: 413 st->print("|HC "); 414 break; 415 case _cset: 416 st->print("|CS "); 417 break; 418 case _trash: 419 st->print("|TR "); 420 break; 421 case _pinned: 422 st->print("|P "); 423 break; 424 case _pinned_cset: 425 st->print("|CSP"); 426 break; 427 default: 428 ShouldNotReachHere(); 429 } 430 431 st->print("|%s", shenandoah_affiliation_code(affiliation())); 432 433 #define SHR_PTR_FORMAT "%12" PRIxPTR 434 435 st->print("|BTE " SHR_PTR_FORMAT ", " SHR_PTR_FORMAT ", " SHR_PTR_FORMAT, 436 p2i(bottom()), p2i(top()), p2i(end())); 437 st->print("|TAMS " SHR_PTR_FORMAT, 438 p2i(ShenandoahHeap::heap()->marking_context()->top_at_mark_start(const_cast<ShenandoahHeapRegion*>(this)))); 439 st->print("|UWM " SHR_PTR_FORMAT, 440 p2i(_update_watermark)); 441 st->print("|U " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 442 st->print("|T " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_tlab_allocs()), proper_unit_for_byte_size(get_tlab_allocs())); 443 st->print("|G " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_gclab_allocs()), proper_unit_for_byte_size(get_gclab_allocs())); 444 if (ShenandoahHeap::heap()->mode()->is_generational()) { 445 st->print("|P " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_plab_allocs()), proper_unit_for_byte_size(get_plab_allocs())); 446 } 447 st->print("|S " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_shared_allocs()), proper_unit_for_byte_size(get_shared_allocs())); 448 st->print("|L " SIZE_FORMAT_W(5) "%1s", byte_size_in_proper_unit(get_live_data_bytes()), proper_unit_for_byte_size(get_live_data_bytes())); 449 st->print("|CP " SIZE_FORMAT_W(3), pin_count()); 450 st->cr(); 451 452 #undef SHR_PTR_FORMAT 453 } 454 455 // oop_iterate without closure and without cancellation. always return true. 456 bool ShenandoahHeapRegion::oop_fill_and_coalesce_without_cancel() { 457 HeapWord* obj_addr = resume_coalesce_and_fill(); 458 459 assert(!is_humongous(), "No need to fill or coalesce humongous regions"); 460 if (!is_active()) { 461 end_preemptible_coalesce_and_fill(); 462 return true; 463 } 464 465 ShenandoahHeap* heap = ShenandoahHeap::heap(); 466 ShenandoahMarkingContext* marking_context = heap->marking_context(); 467 // All objects above TAMS are considered live even though their mark bits will not be set. Note that young- 468 // gen evacuations that interrupt a long-running old-gen concurrent mark may promote objects into old-gen 469 // while the old-gen concurrent marking is ongoing. These newly promoted objects will reside above TAMS 470 // and will be treated as live during the current old-gen marking pass, even though they will not be 471 // explicitly marked. 472 HeapWord* t = marking_context->top_at_mark_start(this); 473 474 // Expect marking to be completed before these threads invoke this service. 475 assert(heap->active_generation()->is_mark_complete(), "sanity"); 476 while (obj_addr < t) { 477 oop obj = cast_to_oop(obj_addr); 478 if (marking_context->is_marked(obj)) { 479 assert(obj->klass() != nullptr, "klass should not be nullptr"); 480 obj_addr += obj->size(); 481 } else { 482 // Object is not marked. Coalesce and fill dead object with dead neighbors. 483 HeapWord* next_marked_obj = marking_context->get_next_marked_addr(obj_addr, t); 484 assert(next_marked_obj <= t, "next marked object cannot exceed top"); 485 size_t fill_size = next_marked_obj - obj_addr; 486 assert(fill_size >= ShenandoahHeap::min_fill_size(), "previously allocated objects known to be larger than min_size"); 487 ShenandoahHeap::fill_with_object(obj_addr, fill_size); 488 heap->card_scan()->coalesce_objects(obj_addr, fill_size); 489 obj_addr = next_marked_obj; 490 } 491 } 492 // Mark that this region has been coalesced and filled 493 end_preemptible_coalesce_and_fill(); 494 return true; 495 } 496 497 // oop_iterate without closure, return true if completed without cancellation 498 bool ShenandoahHeapRegion::oop_fill_and_coalesce() { 499 HeapWord* obj_addr = resume_coalesce_and_fill(); 500 // Consider yielding to cancel/preemption request after this many coalesce operations (skip marked, or coalesce free). 501 const size_t preemption_stride = 128; 502 503 assert(!is_humongous(), "No need to fill or coalesce humongous regions"); 504 if (!is_active()) { 505 end_preemptible_coalesce_and_fill(); 506 return true; 507 } 508 509 ShenandoahHeap* heap = ShenandoahHeap::heap(); 510 ShenandoahMarkingContext* marking_context = heap->marking_context(); 511 // All objects above TAMS are considered live even though their mark bits will not be set. Note that young- 512 // gen evacuations that interrupt a long-running old-gen concurrent mark may promote objects into old-gen 513 // while the old-gen concurrent marking is ongoing. These newly promoted objects will reside above TAMS 514 // and will be treated as live during the current old-gen marking pass, even though they will not be 515 // explicitly marked. 516 HeapWord* t = marking_context->top_at_mark_start(this); 517 518 // Expect marking to be completed before these threads invoke this service. 519 assert(heap->active_generation()->is_mark_complete(), "sanity"); 520 521 size_t ops_before_preempt_check = preemption_stride; 522 while (obj_addr < t) { 523 oop obj = cast_to_oop(obj_addr); 524 if (marking_context->is_marked(obj)) { 525 assert(obj->klass() != nullptr, "klass should not be nullptr"); 526 obj_addr += obj->size(); 527 } else { 528 // Object is not marked. Coalesce and fill dead object with dead neighbors. 529 HeapWord* next_marked_obj = marking_context->get_next_marked_addr(obj_addr, t); 530 assert(next_marked_obj <= t, "next marked object cannot exceed top"); 531 size_t fill_size = next_marked_obj - obj_addr; 532 assert(fill_size >= ShenandoahHeap::min_fill_size(), "previously allocated object known to be larger than min_size"); 533 ShenandoahHeap::fill_with_object(obj_addr, fill_size); 534 heap->card_scan()->coalesce_objects(obj_addr, fill_size); 535 obj_addr = next_marked_obj; 536 } 537 if (ops_before_preempt_check-- == 0) { 538 if (heap->cancelled_gc()) { 539 suspend_coalesce_and_fill(obj_addr); 540 return false; 541 } 542 ops_before_preempt_check = preemption_stride; 543 } 544 } 545 // Mark that this region has been coalesced and filled 546 end_preemptible_coalesce_and_fill(); 547 return true; 548 } 549 550 // DO NOT CANCEL. If this worker thread has accepted responsibility for scanning a particular range of addresses, it 551 // must finish the work before it can be cancelled. 552 void ShenandoahHeapRegion::oop_iterate_humongous_slice(OopIterateClosure* blk, bool dirty_only, 553 HeapWord* start, size_t words, bool write_table) { 554 assert(words % CardTable::card_size_in_words() == 0, "Humongous iteration must span whole number of cards"); 555 assert(is_humongous(), "only humongous region here"); 556 ShenandoahHeap* heap = ShenandoahHeap::heap(); 557 558 // Find head. 559 ShenandoahHeapRegion* r = humongous_start_region(); 560 assert(r->is_humongous_start(), "need humongous head here"); 561 assert(CardTable::card_size_in_words() * (words / CardTable::card_size_in_words()) == words, 562 "slice must be integral number of cards"); 563 564 oop obj = cast_to_oop(r->bottom()); 565 RememberedScanner* scanner = ShenandoahHeap::heap()->card_scan(); 566 size_t card_index = scanner->card_index_for_addr(start); 567 size_t num_cards = words / CardTable::card_size_in_words(); 568 569 if (dirty_only) { 570 if (write_table) { 571 while (num_cards-- > 0) { 572 if (scanner->is_write_card_dirty(card_index++)) { 573 obj->oop_iterate(blk, MemRegion(start, start + CardTable::card_size_in_words())); 574 } 575 start += CardTable::card_size_in_words(); 576 } 577 } else { 578 while (num_cards-- > 0) { 579 if (scanner->is_card_dirty(card_index++)) { 580 obj->oop_iterate(blk, MemRegion(start, start + CardTable::card_size_in_words())); 581 } 582 start += CardTable::card_size_in_words(); 583 } 584 } 585 } else { 586 // Scan all data, regardless of whether cards are dirty 587 obj->oop_iterate(blk, MemRegion(start, start + num_cards * CardTable::card_size_in_words())); 588 } 589 } 590 591 ShenandoahHeapRegion* ShenandoahHeapRegion::humongous_start_region() const { 592 ShenandoahHeap* heap = ShenandoahHeap::heap(); 593 assert(is_humongous(), "Must be a part of the humongous region"); 594 size_t i = index(); 595 ShenandoahHeapRegion* r = const_cast<ShenandoahHeapRegion*>(this); 596 while (!r->is_humongous_start()) { 597 assert(i > 0, "Sanity"); 598 i--; 599 r = heap->get_region(i); 600 assert(r->is_humongous(), "Must be a part of the humongous region"); 601 } 602 assert(r->is_humongous_start(), "Must be"); 603 return r; 604 } 605 606 void ShenandoahHeapRegion::recycle() { 607 shenandoah_assert_heaplocked(); 608 ShenandoahHeap* heap = ShenandoahHeap::heap(); 609 ShenandoahGeneration* generation = heap->generation_for(affiliation()); 610 611 heap->decrease_used(generation, used()); 612 generation->decrement_affiliated_region_count(); 613 614 set_top(bottom()); 615 clear_live_data(); 616 617 reset_alloc_metadata(); 618 619 heap->marking_context()->reset_top_at_mark_start(this); 620 set_update_watermark(bottom()); 621 622 make_empty(); 623 624 set_affiliation(FREE); 625 if (ZapUnusedHeapArea) { 626 SpaceMangler::mangle_region(MemRegion(bottom(), end())); 627 } 628 } 629 630 HeapWord* ShenandoahHeapRegion::block_start(const void* p) const { 631 assert(MemRegion(bottom(), end()).contains(p), 632 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 633 p2i(p), p2i(bottom()), p2i(end())); 634 if (p >= top()) { 635 return top(); 636 } else { 637 HeapWord* last = bottom(); 638 HeapWord* cur = last; 639 while (cur <= p) { 640 last = cur; 641 cur += cast_to_oop(cur)->size(); 642 } 643 shenandoah_assert_correct(nullptr, cast_to_oop(last)); 644 return last; 645 } 646 } 647 648 size_t ShenandoahHeapRegion::block_size(const HeapWord* p) const { 649 assert(MemRegion(bottom(), end()).contains(p), 650 "p (" PTR_FORMAT ") not in space [" PTR_FORMAT ", " PTR_FORMAT ")", 651 p2i(p), p2i(bottom()), p2i(end())); 652 if (p < top()) { 653 return cast_to_oop(p)->size(); 654 } else { 655 assert(p == top(), "just checking"); 656 return pointer_delta(end(), (HeapWord*) p); 657 } 658 } 659 660 size_t ShenandoahHeapRegion::setup_sizes(size_t max_heap_size) { 661 // Absolute minimums we should not ever break. 662 static const size_t MIN_REGION_SIZE = 256*K; 663 664 if (FLAG_IS_DEFAULT(ShenandoahMinRegionSize)) { 665 FLAG_SET_DEFAULT(ShenandoahMinRegionSize, MIN_REGION_SIZE); 666 } 667 668 // Generational Shenandoah needs this alignment for card tables. 669 if (strcmp(ShenandoahGCMode, "generational") == 0) { 670 max_heap_size = align_up(max_heap_size , CardTable::ct_max_alignment_constraint()); 671 } 672 673 size_t region_size; 674 if (FLAG_IS_DEFAULT(ShenandoahRegionSize)) { 675 if (ShenandoahMinRegionSize > max_heap_size / MIN_NUM_REGIONS) { 676 err_msg message("Max heap size (" SIZE_FORMAT "%s) is too low to afford the minimum number " 677 "of regions (" SIZE_FORMAT ") of minimum region size (" SIZE_FORMAT "%s).", 678 byte_size_in_proper_unit(max_heap_size), proper_unit_for_byte_size(max_heap_size), 679 MIN_NUM_REGIONS, 680 byte_size_in_proper_unit(ShenandoahMinRegionSize), proper_unit_for_byte_size(ShenandoahMinRegionSize)); 681 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message); 682 } 683 if (ShenandoahMinRegionSize < MIN_REGION_SIZE) { 684 err_msg message("" SIZE_FORMAT "%s should not be lower than minimum region size (" SIZE_FORMAT "%s).", 685 byte_size_in_proper_unit(ShenandoahMinRegionSize), proper_unit_for_byte_size(ShenandoahMinRegionSize), 686 byte_size_in_proper_unit(MIN_REGION_SIZE), proper_unit_for_byte_size(MIN_REGION_SIZE)); 687 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message); 688 } 689 if (ShenandoahMinRegionSize < MinTLABSize) { 690 err_msg message("" SIZE_FORMAT "%s should not be lower than TLAB size size (" SIZE_FORMAT "%s).", 691 byte_size_in_proper_unit(ShenandoahMinRegionSize), proper_unit_for_byte_size(ShenandoahMinRegionSize), 692 byte_size_in_proper_unit(MinTLABSize), proper_unit_for_byte_size(MinTLABSize)); 693 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize option", message); 694 } 695 if (ShenandoahMaxRegionSize < MIN_REGION_SIZE) { 696 err_msg message("" SIZE_FORMAT "%s should not be lower than min region size (" SIZE_FORMAT "%s).", 697 byte_size_in_proper_unit(ShenandoahMaxRegionSize), proper_unit_for_byte_size(ShenandoahMaxRegionSize), 698 byte_size_in_proper_unit(MIN_REGION_SIZE), proper_unit_for_byte_size(MIN_REGION_SIZE)); 699 vm_exit_during_initialization("Invalid -XX:ShenandoahMaxRegionSize option", message); 700 } 701 if (ShenandoahMinRegionSize > ShenandoahMaxRegionSize) { 702 err_msg message("Minimum (" SIZE_FORMAT "%s) should be larger than maximum (" SIZE_FORMAT "%s).", 703 byte_size_in_proper_unit(ShenandoahMinRegionSize), proper_unit_for_byte_size(ShenandoahMinRegionSize), 704 byte_size_in_proper_unit(ShenandoahMaxRegionSize), proper_unit_for_byte_size(ShenandoahMaxRegionSize)); 705 vm_exit_during_initialization("Invalid -XX:ShenandoahMinRegionSize or -XX:ShenandoahMaxRegionSize", message); 706 } 707 708 // We rapidly expand to max_heap_size in most scenarios, so that is the measure 709 // for usual heap sizes. Do not depend on initial_heap_size here. 710 region_size = max_heap_size / ShenandoahTargetNumRegions; 711 712 // Now make sure that we don't go over or under our limits. 713 region_size = MAX2(ShenandoahMinRegionSize, region_size); 714 region_size = MIN2(ShenandoahMaxRegionSize, region_size); 715 716 } else { 717 if (ShenandoahRegionSize > max_heap_size / MIN_NUM_REGIONS) { 718 err_msg message("Max heap size (" SIZE_FORMAT "%s) is too low to afford the minimum number " 719 "of regions (" SIZE_FORMAT ") of requested size (" SIZE_FORMAT "%s).", 720 byte_size_in_proper_unit(max_heap_size), proper_unit_for_byte_size(max_heap_size), 721 MIN_NUM_REGIONS, 722 byte_size_in_proper_unit(ShenandoahRegionSize), proper_unit_for_byte_size(ShenandoahRegionSize)); 723 vm_exit_during_initialization("Invalid -XX:ShenandoahRegionSize option", message); 724 } 725 if (ShenandoahRegionSize < ShenandoahMinRegionSize) { 726 err_msg message("Heap region size (" SIZE_FORMAT "%s) should be larger than min region size (" SIZE_FORMAT "%s).", 727 byte_size_in_proper_unit(ShenandoahRegionSize), proper_unit_for_byte_size(ShenandoahRegionSize), 728 byte_size_in_proper_unit(ShenandoahMinRegionSize), proper_unit_for_byte_size(ShenandoahMinRegionSize)); 729 vm_exit_during_initialization("Invalid -XX:ShenandoahRegionSize option", message); 730 } 731 if (ShenandoahRegionSize > ShenandoahMaxRegionSize) { 732 err_msg message("Heap region size (" SIZE_FORMAT "%s) should be lower than max region size (" SIZE_FORMAT "%s).", 733 byte_size_in_proper_unit(ShenandoahRegionSize), proper_unit_for_byte_size(ShenandoahRegionSize), 734 byte_size_in_proper_unit(ShenandoahMaxRegionSize), proper_unit_for_byte_size(ShenandoahMaxRegionSize)); 735 vm_exit_during_initialization("Invalid -XX:ShenandoahRegionSize option", message); 736 } 737 region_size = ShenandoahRegionSize; 738 } 739 740 // Make sure region size and heap size are page aligned. 741 // If large pages are used, we ensure that region size is aligned to large page size if 742 // heap size is large enough to accommodate minimal number of regions. Otherwise, we align 743 // region size to regular page size. 744 745 // Figure out page size to use, and aligns up heap to page size 746 size_t page_size = os::vm_page_size(); 747 if (UseLargePages) { 748 size_t large_page_size = os::large_page_size(); 749 max_heap_size = align_up(max_heap_size, large_page_size); 750 if ((max_heap_size / align_up(region_size, large_page_size)) >= MIN_NUM_REGIONS) { 751 page_size = large_page_size; 752 } else { 753 // Should have been checked during argument initialization 754 assert(!ShenandoahUncommit, "Uncommit requires region size aligns to large page size"); 755 } 756 } else { 757 max_heap_size = align_up(max_heap_size, page_size); 758 } 759 760 // Align region size to page size 761 region_size = align_up(region_size, page_size); 762 763 int region_size_log = log2i(region_size); 764 // Recalculate the region size to make sure it's a power of 765 // 2. This means that region_size is the largest power of 2 that's 766 // <= what we've calculated so far. 767 region_size = size_t(1) << region_size_log; 768 769 // Now, set up the globals. 770 guarantee(RegionSizeBytesShift == 0, "we should only set it once"); 771 RegionSizeBytesShift = (size_t)region_size_log; 772 773 guarantee(RegionSizeWordsShift == 0, "we should only set it once"); 774 RegionSizeWordsShift = RegionSizeBytesShift - LogHeapWordSize; 775 776 guarantee(RegionSizeBytes == 0, "we should only set it once"); 777 RegionSizeBytes = region_size; 778 RegionSizeWords = RegionSizeBytes >> LogHeapWordSize; 779 assert (RegionSizeWords*HeapWordSize == RegionSizeBytes, "sanity"); 780 781 guarantee(RegionSizeWordsMask == 0, "we should only set it once"); 782 RegionSizeWordsMask = RegionSizeWords - 1; 783 784 guarantee(RegionSizeBytesMask == 0, "we should only set it once"); 785 RegionSizeBytesMask = RegionSizeBytes - 1; 786 787 guarantee(RegionCount == 0, "we should only set it once"); 788 RegionCount = align_up(max_heap_size, RegionSizeBytes) / RegionSizeBytes; 789 guarantee(RegionCount >= MIN_NUM_REGIONS, "Should have at least minimum regions"); 790 791 guarantee(HumongousThresholdWords == 0, "we should only set it once"); 792 HumongousThresholdWords = RegionSizeWords * ShenandoahHumongousThreshold / 100; 793 HumongousThresholdWords = align_down(HumongousThresholdWords, MinObjAlignment); 794 assert (HumongousThresholdWords <= RegionSizeWords, "sanity"); 795 796 guarantee(HumongousThresholdBytes == 0, "we should only set it once"); 797 HumongousThresholdBytes = HumongousThresholdWords * HeapWordSize; 798 assert (HumongousThresholdBytes <= RegionSizeBytes, "sanity"); 799 800 guarantee(MaxTLABSizeWords == 0, "we should only set it once"); 801 MaxTLABSizeWords = MIN2(RegionSizeWords, HumongousThresholdWords); 802 MaxTLABSizeWords = align_down(MaxTLABSizeWords, MinObjAlignment); 803 804 guarantee(MaxTLABSizeBytes == 0, "we should only set it once"); 805 MaxTLABSizeBytes = MaxTLABSizeWords * HeapWordSize; 806 assert (MaxTLABSizeBytes > MinTLABSize, "should be larger"); 807 808 return max_heap_size; 809 } 810 811 void ShenandoahHeapRegion::do_commit() { 812 ShenandoahHeap* heap = ShenandoahHeap::heap(); 813 if (!heap->is_heap_region_special() && !os::commit_memory((char *) bottom(), RegionSizeBytes, false)) { 814 report_java_out_of_memory("Unable to commit region"); 815 } 816 if (!heap->commit_bitmap_slice(this)) { 817 report_java_out_of_memory("Unable to commit bitmaps for region"); 818 } 819 if (AlwaysPreTouch) { 820 os::pretouch_memory(bottom(), end(), heap->pretouch_heap_page_size()); 821 } 822 heap->increase_committed(ShenandoahHeapRegion::region_size_bytes()); 823 } 824 825 void ShenandoahHeapRegion::do_uncommit() { 826 ShenandoahHeap* heap = ShenandoahHeap::heap(); 827 if (!heap->is_heap_region_special() && !os::uncommit_memory((char *) bottom(), RegionSizeBytes)) { 828 report_java_out_of_memory("Unable to uncommit region"); 829 } 830 if (!heap->uncommit_bitmap_slice(this)) { 831 report_java_out_of_memory("Unable to uncommit bitmaps for region"); 832 } 833 heap->decrease_committed(ShenandoahHeapRegion::region_size_bytes()); 834 } 835 836 void ShenandoahHeapRegion::set_state(RegionState to) { 837 EventShenandoahHeapRegionStateChange evt; 838 if (evt.should_commit()){ 839 evt.set_index((unsigned) index()); 840 evt.set_start((uintptr_t)bottom()); 841 evt.set_used(used()); 842 evt.set_from(_state); 843 evt.set_to(to); 844 evt.commit(); 845 } 846 _state = to; 847 } 848 849 void ShenandoahHeapRegion::record_pin() { 850 Atomic::add(&_critical_pins, (size_t)1); 851 } 852 853 void ShenandoahHeapRegion::record_unpin() { 854 assert(pin_count() > 0, "Region " SIZE_FORMAT " should have non-zero pins", index()); 855 Atomic::sub(&_critical_pins, (size_t)1); 856 } 857 858 size_t ShenandoahHeapRegion::pin_count() const { 859 return Atomic::load(&_critical_pins); 860 } 861 862 void ShenandoahHeapRegion::set_affiliation(ShenandoahAffiliation new_affiliation) { 863 ShenandoahHeap* heap = ShenandoahHeap::heap(); 864 865 ShenandoahAffiliation region_affiliation = heap->region_affiliation(this); 866 { 867 ShenandoahMarkingContext* const ctx = heap->complete_marking_context(); 868 log_debug(gc)("Setting affiliation of Region " SIZE_FORMAT " from %s to %s, top: " PTR_FORMAT ", TAMS: " PTR_FORMAT 869 ", watermark: " PTR_FORMAT ", top_bitmap: " PTR_FORMAT, 870 index(), shenandoah_affiliation_name(region_affiliation), shenandoah_affiliation_name(new_affiliation), 871 p2i(top()), p2i(ctx->top_at_mark_start(this)), p2i(_update_watermark), p2i(ctx->top_bitmap(this))); 872 } 873 874 #ifdef ASSERT 875 { 876 // During full gc, heap->complete_marking_context() is not valid, may equal nullptr. 877 ShenandoahMarkingContext* const ctx = heap->complete_marking_context(); 878 size_t idx = this->index(); 879 HeapWord* top_bitmap = ctx->top_bitmap(this); 880 881 assert(ctx->is_bitmap_clear_range(top_bitmap, _end), 882 "Region " SIZE_FORMAT ", bitmap should be clear between top_bitmap: " PTR_FORMAT " and end: " PTR_FORMAT, idx, 883 p2i(top_bitmap), p2i(_end)); 884 } 885 #endif 886 887 if (region_affiliation == new_affiliation) { 888 return; 889 } 890 891 if (!heap->mode()->is_generational()) { 892 log_trace(gc)("Changing affiliation of region %zu from %s to %s", 893 index(), affiliation_name(), shenandoah_affiliation_name(new_affiliation)); 894 heap->set_affiliation(this, new_affiliation); 895 return; 896 } 897 898 switch (new_affiliation) { 899 case FREE: 900 assert(!has_live(), "Free region should not have live data"); 901 break; 902 case YOUNG_GENERATION: 903 reset_age(); 904 break; 905 case OLD_GENERATION: 906 // TODO: should we reset_age() for OLD as well? Examine invocations of set_affiliation(). Some contexts redundantly 907 // invoke reset_age(). 908 break; 909 default: 910 ShouldNotReachHere(); 911 return; 912 } 913 heap->set_affiliation(this, new_affiliation); 914 } 915 916 void ShenandoahHeapRegion::decrement_humongous_waste() const { 917 assert(is_humongous(), "Should only use this for humongous regions"); 918 size_t waste_bytes = free(); 919 if (waste_bytes > 0) { 920 ShenandoahHeap* heap = ShenandoahHeap::heap(); 921 ShenandoahGeneration* generation = heap->generation_for(affiliation()); 922 heap->decrease_humongous_waste(generation, waste_bytes); 923 } 924 }