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