1 /* 2 * Copyright (c) 2013, 2020, Red Hat, Inc. 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 "memory/allocation.hpp" 27 #include "memory/universe.hpp" 28 29 #include "gc/shared/gcArguments.hpp" 30 #include "gc/shared/gcTimer.hpp" 31 #include "gc/shared/gcTraceTime.inline.hpp" 32 #include "gc/shared/locationPrinter.inline.hpp" 33 #include "gc/shared/memAllocator.hpp" 34 #include "gc/shared/oopStorageSet.hpp" 35 #include "gc/shared/plab.hpp" 36 37 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 38 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 39 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 40 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 41 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" 42 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp" 43 #include "gc/shenandoah/shenandoahControlThread.hpp" 44 #include "gc/shenandoah/shenandoahFreeSet.hpp" 45 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 46 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 47 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 48 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 49 #include "gc/shenandoah/shenandoahIUMode.hpp" 50 #include "gc/shenandoah/shenandoahMarkCompact.hpp" 51 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 52 #include "gc/shenandoah/shenandoahMemoryPool.hpp" 53 #include "gc/shenandoah/shenandoahMetrics.hpp" 54 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp" 55 #include "gc/shenandoah/shenandoahNormalMode.hpp" 56 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 57 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 58 #include "gc/shenandoah/shenandoahPadding.hpp" 59 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp" 60 #include "gc/shenandoah/shenandoahPassiveMode.hpp" 61 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 62 #include "gc/shenandoah/shenandoahStringDedup.hpp" 63 #include "gc/shenandoah/shenandoahTaskqueue.hpp" 64 #include "gc/shenandoah/shenandoahUtils.hpp" 65 #include "gc/shenandoah/shenandoahVerifier.hpp" 66 #include "gc/shenandoah/shenandoahCodeRoots.hpp" 67 #include "gc/shenandoah/shenandoahVMOperations.hpp" 68 #include "gc/shenandoah/shenandoahWorkGroup.hpp" 69 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp" 70 #if INCLUDE_JFR 71 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 72 #endif 73 74 #include "memory/metaspace.hpp" 75 #include "oops/compressedOops.inline.hpp" 76 #include "runtime/atomic.hpp" 77 #include "runtime/globals.hpp" 78 #include "runtime/interfaceSupport.inline.hpp" 79 #include "runtime/orderAccess.hpp" 80 #include "runtime/safepointMechanism.hpp" 81 #include "runtime/vmThread.hpp" 82 #include "services/mallocTracker.hpp" 83 #include "utilities/powerOfTwo.hpp" 84 85 ShenandoahHeap* ShenandoahHeap::_heap = NULL; 86 87 #ifdef ASSERT 88 template <class T> 89 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) { 90 T o = RawAccess<>::oop_load(p); 91 if (! CompressedOops::is_null(o)) { 92 oop obj = CompressedOops::decode_not_null(o); 93 shenandoah_assert_not_forwarded(p, obj); 94 } 95 } 96 97 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); } 98 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); } 99 #endif 100 101 class ShenandoahPretouchHeapTask : public AbstractGangTask { 102 private: 103 ShenandoahRegionIterator _regions; 104 const size_t _page_size; 105 public: 106 ShenandoahPretouchHeapTask(size_t page_size) : 107 AbstractGangTask("Shenandoah Pretouch Heap"), 108 _page_size(page_size) {} 109 110 virtual void work(uint worker_id) { 111 ShenandoahHeapRegion* r = _regions.next(); 112 while (r != NULL) { 113 os::pretouch_memory(r->bottom(), r->end(), _page_size); 114 r = _regions.next(); 115 } 116 } 117 }; 118 119 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 120 private: 121 ShenandoahRegionIterator _regions; 122 char* _bitmap_base; 123 const size_t _bitmap_size; 124 const size_t _page_size; 125 public: 126 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 127 AbstractGangTask("Shenandoah Pretouch Bitmap"), 128 _bitmap_base(bitmap_base), 129 _bitmap_size(bitmap_size), 130 _page_size(page_size) {} 131 132 virtual void work(uint worker_id) { 133 ShenandoahHeapRegion* r = _regions.next(); 134 while (r != NULL) { 135 size_t start = r->index() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 136 size_t end = (r->index() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 137 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 138 139 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 140 141 r = _regions.next(); 142 } 143 } 144 }; 145 146 jint ShenandoahHeap::initialize() { 147 initialize_heuristics(); 148 149 // 150 // Figure out heap sizing 151 // 152 153 size_t init_byte_size = InitialHeapSize; 154 size_t min_byte_size = MinHeapSize; 155 size_t max_byte_size = MaxHeapSize; 156 size_t heap_alignment = HeapAlignment; 157 158 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 159 160 if (ShenandoahAlwaysPreTouch) { 161 // Enabled pre-touch means the entire heap is committed right away. 162 init_byte_size = max_byte_size; 163 } 164 165 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 166 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 167 168 _num_regions = ShenandoahHeapRegion::region_count(); 169 170 size_t num_committed_regions = init_byte_size / reg_size_bytes; 171 num_committed_regions = MIN2(num_committed_regions, _num_regions); 172 assert(num_committed_regions <= _num_regions, "sanity"); 173 _initial_size = num_committed_regions * reg_size_bytes; 174 175 size_t num_min_regions = min_byte_size / reg_size_bytes; 176 num_min_regions = MIN2(num_min_regions, _num_regions); 177 assert(num_min_regions <= _num_regions, "sanity"); 178 _minimum_size = num_min_regions * reg_size_bytes; 179 180 _committed = _initial_size; 181 182 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 183 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 184 size_t region_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 185 186 // 187 // Reserve and commit memory for heap 188 // 189 190 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 191 initialize_reserved_region(heap_rs); 192 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 193 _heap_region_special = heap_rs.special(); 194 195 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 196 "Misaligned heap: " PTR_FORMAT, p2i(base())); 197 198 #if SHENANDOAH_OPTIMIZED_OBJTASK 199 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 200 // Fail if we ever attempt to address more than we can. 201 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) { 202 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 203 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 204 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 205 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable()); 206 vm_exit_during_initialization("Fatal Error", buf); 207 } 208 #endif 209 210 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 211 if (!_heap_region_special) { 212 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 213 "Cannot commit heap memory"); 214 } 215 216 // 217 // Reserve and commit memory for bitmap(s) 218 // 219 220 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 221 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 222 223 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 224 225 guarantee(bitmap_bytes_per_region != 0, 226 "Bitmap bytes per region should not be zero"); 227 guarantee(is_power_of_2(bitmap_bytes_per_region), 228 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 229 230 if (bitmap_page_size > bitmap_bytes_per_region) { 231 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 232 _bitmap_bytes_per_slice = bitmap_page_size; 233 } else { 234 _bitmap_regions_per_slice = 1; 235 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 236 } 237 238 guarantee(_bitmap_regions_per_slice >= 1, 239 "Should have at least one region per slice: " SIZE_FORMAT, 240 _bitmap_regions_per_slice); 241 242 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 243 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 244 _bitmap_bytes_per_slice, bitmap_page_size); 245 246 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 247 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 248 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 249 _bitmap_region_special = bitmap.special(); 250 251 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 252 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 253 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 254 if (!_bitmap_region_special) { 255 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 256 "Cannot commit bitmap memory"); 257 } 258 259 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 260 261 if (ShenandoahVerify) { 262 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 263 if (!verify_bitmap.special()) { 264 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 265 "Cannot commit verification bitmap memory"); 266 } 267 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 268 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 269 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 270 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 271 } 272 273 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 274 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 275 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 276 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 277 _aux_bitmap_region_special = aux_bitmap.special(); 278 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 279 280 // 281 // Create regions and region sets 282 // 283 size_t region_align = align_up(sizeof(ShenandoahHeapRegion), SHENANDOAH_CACHE_LINE_SIZE); 284 size_t region_storage_size = align_up(region_align * _num_regions, region_page_size); 285 286 ReservedSpace region_storage(region_storage_size, region_page_size); 287 MemTracker::record_virtual_memory_type(region_storage.base(), mtGC); 288 if (!region_storage.special()) { 289 os::commit_memory_or_exit(region_storage.base(), region_storage_size, region_page_size, false, 290 "Cannot commit region memory"); 291 } 292 293 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 294 _free_set = new ShenandoahFreeSet(this, _num_regions); 295 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 296 297 { 298 ShenandoahHeapLocker locker(lock()); 299 300 for (size_t i = 0; i < _num_regions; i++) { 301 HeapWord* start = (HeapWord*)sh_rs.base() + ShenandoahHeapRegion::region_size_words() * i; 302 bool is_committed = i < num_committed_regions; 303 void* loc = region_storage.base() + i * region_align; 304 305 ShenandoahHeapRegion* r = new (loc) ShenandoahHeapRegion(start, i, is_committed); 306 assert(is_aligned(r, SHENANDOAH_CACHE_LINE_SIZE), "Sanity"); 307 308 _marking_context->initialize_top_at_mark_start(r); 309 _regions[i] = r; 310 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 311 } 312 313 // Initialize to complete 314 _marking_context->mark_complete(); 315 316 _free_set->rebuild(); 317 } 318 319 if (ShenandoahAlwaysPreTouch) { 320 assert(!AlwaysPreTouch, "Should have been overridden"); 321 322 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 323 // before initialize() below zeroes it with initializing thread. For any given region, 324 // we touch the region and the corresponding bitmaps from the same thread. 325 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 326 327 size_t pretouch_heap_page_size = heap_page_size; 328 size_t pretouch_bitmap_page_size = bitmap_page_size; 329 330 #ifdef LINUX 331 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 332 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 333 // them into huge one. Therefore, we need to pretouch with smaller pages. 334 if (UseTransparentHugePages) { 335 pretouch_heap_page_size = (size_t)os::vm_page_size(); 336 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 337 } 338 #endif 339 340 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 341 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 342 343 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 344 _num_regions, pretouch_bitmap_page_size); 345 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 346 _workers->run_task(&bcl); 347 348 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 349 _num_regions, pretouch_heap_page_size); 350 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 351 _workers->run_task(&hcl); 352 } 353 354 // 355 // Initialize the rest of GC subsystems 356 // 357 358 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 359 for (uint worker = 0; worker < _max_workers; worker++) { 360 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 361 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 362 } 363 364 // There should probably be Shenandoah-specific options for these, 365 // just as there are G1-specific options. 366 { 367 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set(); 368 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold 369 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent 370 } 371 372 _monitoring_support = new ShenandoahMonitoringSupport(this); 373 _phase_timings = new ShenandoahPhaseTimings(); 374 ShenandoahStringDedup::initialize(); 375 ShenandoahCodeRoots::initialize(); 376 377 if (ShenandoahPacing) { 378 _pacer = new ShenandoahPacer(this); 379 _pacer->setup_for_idle(); 380 } else { 381 _pacer = NULL; 382 } 383 384 _control_thread = new ShenandoahControlThread(); 385 386 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 387 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 388 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 389 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 390 ); 391 392 log_info(gc, init)("Safepointing mechanism: thread-local poll"); 393 394 return JNI_OK; 395 } 396 397 void ShenandoahHeap::initialize_heuristics() { 398 if (ShenandoahGCMode != NULL) { 399 if (strcmp(ShenandoahGCMode, "normal") == 0) { 400 _gc_mode = new ShenandoahNormalMode(); 401 } else if (strcmp(ShenandoahGCMode, "iu") == 0) { 402 _gc_mode = new ShenandoahIUMode(); 403 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 404 _gc_mode = new ShenandoahPassiveMode(); 405 } else { 406 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 407 } 408 } else { 409 ShouldNotReachHere(); 410 } 411 _gc_mode->initialize_flags(); 412 _heuristics = _gc_mode->initialize_heuristics(); 413 414 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 415 vm_exit_during_initialization( 416 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 417 _heuristics->name())); 418 } 419 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 420 vm_exit_during_initialization( 421 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 422 _heuristics->name())); 423 } 424 log_info(gc, init)("Shenandoah heuristics: %s", 425 _heuristics->name()); 426 } 427 428 #ifdef _MSC_VER 429 #pragma warning( push ) 430 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 431 #endif 432 433 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 434 CollectedHeap(), 435 _initial_size(0), 436 _used(0), 437 _committed(0), 438 _bytes_allocated_since_gc_start(0), 439 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), 440 _workers(NULL), 441 _safepoint_workers(NULL), 442 _heap_region_special(false), 443 _num_regions(0), 444 _regions(NULL), 445 _update_refs_iterator(this), 446 _control_thread(NULL), 447 _shenandoah_policy(policy), 448 _heuristics(NULL), 449 _free_set(NULL), 450 _scm(new ShenandoahConcurrentMark()), 451 _full_gc(new ShenandoahMarkCompact()), 452 _pacer(NULL), 453 _verifier(NULL), 454 _phase_timings(NULL), 455 _monitoring_support(NULL), 456 _memory_pool(NULL), 457 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), 458 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), 459 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 460 _soft_ref_policy(), 461 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes), 462 _ref_processor(NULL), 463 _marking_context(NULL), 464 _bitmap_size(0), 465 _bitmap_regions_per_slice(0), 466 _bitmap_bytes_per_slice(0), 467 _bitmap_region_special(false), 468 _aux_bitmap_region_special(false), 469 _liveness_cache(NULL), 470 _collection_set(NULL) 471 { 472 _heap = this; 473 474 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); 475 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); 476 477 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); 478 479 _max_workers = MAX2(_max_workers, 1U); 480 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, 481 /* are_GC_task_threads */ true, 482 /* are_ConcurrentGC_threads */ true); 483 if (_workers == NULL) { 484 vm_exit_during_initialization("Failed necessary allocation."); 485 } else { 486 _workers->initialize_workers(); 487 } 488 489 if (ParallelGCThreads > 1) { 490 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread", 491 ParallelGCThreads, 492 /* are_GC_task_threads */ false, 493 /* are_ConcurrentGC_threads */ false); 494 _safepoint_workers->initialize_workers(); 495 } 496 } 497 498 #ifdef _MSC_VER 499 #pragma warning( pop ) 500 #endif 501 502 class ShenandoahResetBitmapTask : public AbstractGangTask { 503 private: 504 ShenandoahRegionIterator _regions; 505 506 public: 507 ShenandoahResetBitmapTask() : 508 AbstractGangTask("Parallel Reset Bitmap Task") {} 509 510 void work(uint worker_id) { 511 ShenandoahHeapRegion* region = _regions.next(); 512 ShenandoahHeap* heap = ShenandoahHeap::heap(); 513 ShenandoahMarkingContext* const ctx = heap->marking_context(); 514 while (region != NULL) { 515 if (heap->is_bitmap_slice_committed(region)) { 516 ctx->clear_bitmap(region); 517 } 518 region = _regions.next(); 519 } 520 } 521 }; 522 523 void ShenandoahHeap::reset_mark_bitmap() { 524 assert_gc_workers(_workers->active_workers()); 525 mark_incomplete_marking_context(); 526 527 ShenandoahResetBitmapTask task; 528 _workers->run_task(&task); 529 } 530 531 void ShenandoahHeap::print_on(outputStream* st) const { 532 st->print_cr("Shenandoah Heap"); 533 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 534 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 535 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 536 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 537 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 538 num_regions(), 539 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 540 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 541 542 st->print("Status: "); 543 if (has_forwarded_objects()) st->print("has forwarded objects, "); 544 if (is_concurrent_mark_in_progress()) st->print("marking, "); 545 if (is_evacuation_in_progress()) st->print("evacuating, "); 546 if (is_update_refs_in_progress()) st->print("updating refs, "); 547 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 548 if (is_full_gc_in_progress()) st->print("full gc, "); 549 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 550 if (is_concurrent_root_in_progress()) st->print("concurrent roots, "); 551 552 if (cancelled_gc()) { 553 st->print("cancelled"); 554 } else { 555 st->print("not cancelled"); 556 } 557 st->cr(); 558 559 st->print_cr("Reserved region:"); 560 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 561 p2i(reserved_region().start()), 562 p2i(reserved_region().end())); 563 564 ShenandoahCollectionSet* cset = collection_set(); 565 st->print_cr("Collection set:"); 566 if (cset != NULL) { 567 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 568 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 569 } else { 570 st->print_cr(" (NULL)"); 571 } 572 573 st->cr(); 574 MetaspaceUtils::print_on(st); 575 576 if (Verbose) { 577 print_heap_regions_on(st); 578 } 579 } 580 581 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 582 public: 583 void do_thread(Thread* thread) { 584 assert(thread != NULL, "Sanity"); 585 assert(thread->is_Worker_thread(), "Only worker thread expected"); 586 ShenandoahThreadLocalData::initialize_gclab(thread); 587 } 588 }; 589 590 void ShenandoahHeap::post_initialize() { 591 CollectedHeap::post_initialize(); 592 MutexLocker ml(Threads_lock); 593 594 ShenandoahInitWorkerGCLABClosure init_gclabs; 595 _workers->threads_do(&init_gclabs); 596 597 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 598 // Now, we will let WorkGang to initialize gclab when new worker is created. 599 _workers->set_initialize_gclab(); 600 601 _scm->initialize(_max_workers); 602 _full_gc->initialize(_gc_timer); 603 604 ref_processing_init(); 605 606 _heuristics->initialize(); 607 608 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 609 } 610 611 size_t ShenandoahHeap::used() const { 612 return Atomic::load_acquire(&_used); 613 } 614 615 size_t ShenandoahHeap::committed() const { 616 OrderAccess::acquire(); 617 return _committed; 618 } 619 620 void ShenandoahHeap::increase_committed(size_t bytes) { 621 shenandoah_assert_heaplocked_or_safepoint(); 622 _committed += bytes; 623 } 624 625 void ShenandoahHeap::decrease_committed(size_t bytes) { 626 shenandoah_assert_heaplocked_or_safepoint(); 627 _committed -= bytes; 628 } 629 630 void ShenandoahHeap::increase_used(size_t bytes) { 631 Atomic::add(&_used, bytes); 632 } 633 634 void ShenandoahHeap::set_used(size_t bytes) { 635 Atomic::release_store_fence(&_used, bytes); 636 } 637 638 void ShenandoahHeap::decrease_used(size_t bytes) { 639 assert(used() >= bytes, "never decrease heap size by more than we've left"); 640 Atomic::sub(&_used, bytes); 641 } 642 643 void ShenandoahHeap::increase_allocated(size_t bytes) { 644 Atomic::add(&_bytes_allocated_since_gc_start, bytes); 645 } 646 647 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 648 size_t bytes = words * HeapWordSize; 649 if (!waste) { 650 increase_used(bytes); 651 } 652 increase_allocated(bytes); 653 if (ShenandoahPacing) { 654 control_thread()->pacing_notify_alloc(words); 655 if (waste) { 656 pacer()->claim_for_alloc(words, true); 657 } 658 } 659 } 660 661 size_t ShenandoahHeap::capacity() const { 662 return committed(); 663 } 664 665 size_t ShenandoahHeap::max_capacity() const { 666 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 667 } 668 669 size_t ShenandoahHeap::min_capacity() const { 670 return _minimum_size; 671 } 672 673 size_t ShenandoahHeap::initial_capacity() const { 674 return _initial_size; 675 } 676 677 bool ShenandoahHeap::is_in(const void* p) const { 678 HeapWord* heap_base = (HeapWord*) base(); 679 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 680 return p >= heap_base && p < last_region_end; 681 } 682 683 void ShenandoahHeap::op_uncommit(double shrink_before) { 684 assert (ShenandoahUncommit, "should be enabled"); 685 686 // Application allocates from the beginning of the heap, and GC allocates at 687 // the end of it. It is more efficient to uncommit from the end, so that applications 688 // could enjoy the near committed regions. GC allocations are much less frequent, 689 // and therefore can accept the committing costs. 690 691 size_t count = 0; 692 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 693 ShenandoahHeapRegion* r = get_region(i - 1); 694 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 695 ShenandoahHeapLocker locker(lock()); 696 if (r->is_empty_committed()) { 697 // Do not uncommit below minimal capacity 698 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 699 break; 700 } 701 702 r->make_uncommitted(); 703 count++; 704 } 705 } 706 SpinPause(); // allow allocators to take the lock 707 } 708 709 if (count > 0) { 710 control_thread()->notify_heap_changed(); 711 } 712 } 713 714 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 715 // New object should fit the GCLAB size 716 size_t min_size = MAX2(size, PLAB::min_size()); 717 718 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 719 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 720 new_size = MIN2(new_size, PLAB::max_size()); 721 new_size = MAX2(new_size, PLAB::min_size()); 722 723 // Record new heuristic value even if we take any shortcut. This captures 724 // the case when moderately-sized objects always take a shortcut. At some point, 725 // heuristics should catch up with them. 726 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 727 728 if (new_size < size) { 729 // New size still does not fit the object. Fall back to shared allocation. 730 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 731 return NULL; 732 } 733 734 // Retire current GCLAB, and allocate a new one. 735 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 736 gclab->retire(); 737 738 size_t actual_size = 0; 739 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 740 if (gclab_buf == NULL) { 741 return NULL; 742 } 743 744 assert (size <= actual_size, "allocation should fit"); 745 746 if (ZeroTLAB) { 747 // ..and clear it. 748 Copy::zero_to_words(gclab_buf, actual_size); 749 } else { 750 // ...and zap just allocated object. 751 #ifdef ASSERT 752 // Skip mangling the space corresponding to the object header to 753 // ensure that the returned space is not considered parsable by 754 // any concurrent GC thread. 755 size_t hdr_size = oopDesc::header_size(); 756 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 757 #endif // ASSERT 758 } 759 gclab->set_buf(gclab_buf, actual_size); 760 return gclab->allocate(size); 761 } 762 763 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 764 size_t requested_size, 765 size_t* actual_size) { 766 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 767 HeapWord* res = allocate_memory(req); 768 if (res != NULL) { 769 *actual_size = req.actual_size(); 770 } else { 771 *actual_size = 0; 772 } 773 return res; 774 } 775 776 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 777 size_t word_size, 778 size_t* actual_size) { 779 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 780 HeapWord* res = allocate_memory(req); 781 if (res != NULL) { 782 *actual_size = req.actual_size(); 783 } else { 784 *actual_size = 0; 785 } 786 return res; 787 } 788 789 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 790 intptr_t pacer_epoch = 0; 791 bool in_new_region = false; 792 HeapWord* result = NULL; 793 794 if (req.is_mutator_alloc()) { 795 if (ShenandoahPacing) { 796 pacer()->pace_for_alloc(req.size()); 797 pacer_epoch = pacer()->epoch(); 798 } 799 800 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 801 result = allocate_memory_under_lock(req, in_new_region); 802 } 803 804 // Allocation failed, block until control thread reacted, then retry allocation. 805 // 806 // It might happen that one of the threads requesting allocation would unblock 807 // way later after GC happened, only to fail the second allocation, because 808 // other threads have already depleted the free storage. In this case, a better 809 // strategy is to try again, as long as GC makes progress. 810 // 811 // Then, we need to make sure the allocation was retried after at least one 812 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 813 814 size_t tries = 0; 815 816 while (result == NULL && _progress_last_gc.is_set()) { 817 tries++; 818 control_thread()->handle_alloc_failure(req); 819 result = allocate_memory_under_lock(req, in_new_region); 820 } 821 822 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 823 tries++; 824 control_thread()->handle_alloc_failure(req); 825 result = allocate_memory_under_lock(req, in_new_region); 826 } 827 828 } else { 829 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 830 result = allocate_memory_under_lock(req, in_new_region); 831 // Do not call handle_alloc_failure() here, because we cannot block. 832 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 833 } 834 835 if (in_new_region) { 836 control_thread()->notify_heap_changed(); 837 } 838 839 if (result != NULL) { 840 size_t requested = req.size(); 841 size_t actual = req.actual_size(); 842 843 assert (req.is_lab_alloc() || (requested == actual), 844 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 845 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 846 847 if (req.is_mutator_alloc()) { 848 notify_mutator_alloc_words(actual, false); 849 850 // If we requested more than we were granted, give the rest back to pacer. 851 // This only matters if we are in the same pacing epoch: do not try to unpace 852 // over the budget for the other phase. 853 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 854 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 855 } 856 } else { 857 increase_used(actual*HeapWordSize); 858 } 859 } 860 861 return result; 862 } 863 864 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 865 ShenandoahHeapLocker locker(lock()); 866 return _free_set->allocate(req, in_new_region); 867 } 868 869 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 870 bool* gc_overhead_limit_was_exceeded) { 871 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 872 return allocate_memory(req); 873 } 874 875 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 876 size_t size, 877 Metaspace::MetadataType mdtype) { 878 MetaWord* result; 879 880 // Inform metaspace OOM to GC heuristics if class unloading is possible. 881 if (heuristics()->can_unload_classes()) { 882 ShenandoahHeuristics* h = heuristics(); 883 h->record_metaspace_oom(); 884 } 885 886 // Expand and retry allocation 887 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 888 if (result != NULL) { 889 return result; 890 } 891 892 // Start full GC 893 collect(GCCause::_metadata_GC_clear_soft_refs); 894 895 // Retry allocation 896 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 897 if (result != NULL) { 898 return result; 899 } 900 901 // Expand and retry allocation 902 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 903 if (result != NULL) { 904 return result; 905 } 906 907 // Out of memory 908 return NULL; 909 } 910 911 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 912 private: 913 ShenandoahHeap* const _heap; 914 Thread* const _thread; 915 public: 916 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 917 _heap(heap), _thread(Thread::current()) {} 918 919 void do_object(oop p) { 920 shenandoah_assert_marked(NULL, p); 921 if (!p->is_forwarded()) { 922 _heap->evacuate_object(p, _thread); 923 } 924 } 925 }; 926 927 class ShenandoahEvacuationTask : public AbstractGangTask { 928 private: 929 ShenandoahHeap* const _sh; 930 ShenandoahCollectionSet* const _cs; 931 bool _concurrent; 932 public: 933 ShenandoahEvacuationTask(ShenandoahHeap* sh, 934 ShenandoahCollectionSet* cs, 935 bool concurrent) : 936 AbstractGangTask("Parallel Evacuation Task"), 937 _sh(sh), 938 _cs(cs), 939 _concurrent(concurrent) 940 {} 941 942 void work(uint worker_id) { 943 if (_concurrent) { 944 ShenandoahConcurrentWorkerSession worker_session(worker_id); 945 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 946 ShenandoahEvacOOMScope oom_evac_scope; 947 do_work(); 948 } else { 949 ShenandoahParallelWorkerSession worker_session(worker_id); 950 ShenandoahEvacOOMScope oom_evac_scope; 951 do_work(); 952 } 953 } 954 955 private: 956 void do_work() { 957 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 958 ShenandoahHeapRegion* r; 959 while ((r =_cs->claim_next()) != NULL) { 960 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->index()); 961 _sh->marked_object_iterate(r, &cl); 962 963 if (ShenandoahPacing) { 964 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 965 } 966 967 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 968 break; 969 } 970 } 971 } 972 }; 973 974 void ShenandoahHeap::trash_cset_regions() { 975 ShenandoahHeapLocker locker(lock()); 976 977 ShenandoahCollectionSet* set = collection_set(); 978 ShenandoahHeapRegion* r; 979 set->clear_current_index(); 980 while ((r = set->next()) != NULL) { 981 r->make_trash(); 982 } 983 collection_set()->clear(); 984 } 985 986 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 987 st->print_cr("Heap Regions:"); 988 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 989 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 990 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start, UWM=update watermark"); 991 st->print_cr("SN=alloc sequence number"); 992 993 for (size_t i = 0; i < num_regions(); i++) { 994 get_region(i)->print_on(st); 995 } 996 } 997 998 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 999 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1000 1001 oop humongous_obj = oop(start->bottom()); 1002 size_t size = humongous_obj->size(); 1003 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1004 size_t index = start->index() + required_regions - 1; 1005 1006 assert(!start->has_live(), "liveness must be zero"); 1007 1008 for(size_t i = 0; i < required_regions; i++) { 1009 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1010 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1011 ShenandoahHeapRegion* region = get_region(index --); 1012 1013 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1014 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1015 1016 region->make_trash_immediate(); 1017 } 1018 } 1019 1020 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1021 public: 1022 void do_thread(Thread* thread) { 1023 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1024 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1025 gclab->retire(); 1026 } 1027 }; 1028 1029 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 1030 if (UseTLAB) { 1031 CollectedHeap::ensure_parsability(retire_tlabs); 1032 } 1033 ShenandoahRetireGCLABClosure cl; 1034 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1035 cl.do_thread(t); 1036 } 1037 workers()->threads_do(&cl); 1038 } 1039 1040 void ShenandoahHeap::resize_tlabs() { 1041 CollectedHeap::resize_all_tlabs(); 1042 } 1043 1044 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 1045 private: 1046 ShenandoahRootEvacuator* _rp; 1047 1048 public: 1049 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 1050 AbstractGangTask("Shenandoah evacuate and update roots"), 1051 _rp(rp) {} 1052 1053 void work(uint worker_id) { 1054 ShenandoahParallelWorkerSession worker_session(worker_id); 1055 ShenandoahEvacOOMScope oom_evac_scope; 1056 ShenandoahEvacuateUpdateRootsClosure<> cl; 1057 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 1058 _rp->roots_do(worker_id, &cl); 1059 } 1060 }; 1061 1062 void ShenandoahHeap::evacuate_and_update_roots() { 1063 #if COMPILER2_OR_JVMCI 1064 DerivedPointerTable::clear(); 1065 #endif 1066 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1067 { 1068 // Include concurrent roots if current cycle can not process those roots concurrently 1069 ShenandoahRootEvacuator rp(workers()->active_workers(), 1070 ShenandoahPhaseTimings::init_evac, 1071 !ShenandoahConcurrentRoots::should_do_concurrent_roots(), 1072 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 1073 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 1074 workers()->run_task(&roots_task); 1075 } 1076 1077 #if COMPILER2_OR_JVMCI 1078 DerivedPointerTable::update_pointers(); 1079 #endif 1080 } 1081 1082 // Returns size in bytes 1083 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1084 if (ShenandoahElasticTLAB) { 1085 // With Elastic TLABs, return the max allowed size, and let the allocation path 1086 // figure out the safe size for current allocation. 1087 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1088 } else { 1089 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1090 } 1091 } 1092 1093 size_t ShenandoahHeap::max_tlab_size() const { 1094 // Returns size in words 1095 return ShenandoahHeapRegion::max_tlab_size_words(); 1096 } 1097 1098 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure { 1099 public: 1100 void do_thread(Thread* thread) { 1101 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1102 gclab->retire(); 1103 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1104 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1105 } 1106 } 1107 }; 1108 1109 void ShenandoahHeap::retire_and_reset_gclabs() { 1110 ShenandoahRetireAndResetGCLABClosure cl; 1111 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1112 cl.do_thread(t); 1113 } 1114 workers()->threads_do(&cl); 1115 } 1116 1117 void ShenandoahHeap::collect(GCCause::Cause cause) { 1118 control_thread()->request_gc(cause); 1119 } 1120 1121 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1122 //assert(false, "Shouldn't need to do full collections"); 1123 } 1124 1125 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1126 ShenandoahHeapRegion* r = heap_region_containing(addr); 1127 if (r != NULL) { 1128 return r->block_start(addr); 1129 } 1130 return NULL; 1131 } 1132 1133 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1134 ShenandoahHeapRegion* r = heap_region_containing(addr); 1135 return r->block_is_obj(addr); 1136 } 1137 1138 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const { 1139 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr); 1140 } 1141 1142 jlong ShenandoahHeap::millis_since_last_gc() { 1143 double v = heuristics()->time_since_last_gc() * 1000; 1144 assert(0 <= v && v <= max_jlong, "value should fit: %f", v); 1145 return (jlong)v; 1146 } 1147 1148 void ShenandoahHeap::prepare_for_verify() { 1149 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) { 1150 make_parsable(false); 1151 } 1152 } 1153 1154 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1155 workers()->print_worker_threads_on(st); 1156 if (ShenandoahStringDedup::is_enabled()) { 1157 ShenandoahStringDedup::print_worker_threads_on(st); 1158 } 1159 } 1160 1161 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1162 workers()->threads_do(tcl); 1163 if (_safepoint_workers != NULL) { 1164 _safepoint_workers->threads_do(tcl); 1165 } 1166 if (ShenandoahStringDedup::is_enabled()) { 1167 ShenandoahStringDedup::threads_do(tcl); 1168 } 1169 } 1170 1171 void ShenandoahHeap::print_tracing_info() const { 1172 LogTarget(Info, gc, stats) lt; 1173 if (lt.is_enabled()) { 1174 ResourceMark rm; 1175 LogStream ls(lt); 1176 1177 phase_timings()->print_on(&ls); 1178 1179 ls.cr(); 1180 ls.cr(); 1181 1182 shenandoah_policy()->print_gc_stats(&ls); 1183 1184 ls.cr(); 1185 ls.cr(); 1186 1187 if (ShenandoahPacing) { 1188 pacer()->print_on(&ls); 1189 } 1190 1191 ls.cr(); 1192 ls.cr(); 1193 } 1194 } 1195 1196 void ShenandoahHeap::verify(VerifyOption vo) { 1197 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1198 if (ShenandoahVerify) { 1199 verifier()->verify_generic(vo); 1200 } else { 1201 // TODO: Consider allocating verification bitmaps on demand, 1202 // and turn this on unconditionally. 1203 } 1204 } 1205 } 1206 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1207 return _free_set->capacity(); 1208 } 1209 1210 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1211 private: 1212 MarkBitMap* _bitmap; 1213 Stack<oop,mtGC>* _oop_stack; 1214 ShenandoahHeap* const _heap; 1215 ShenandoahMarkingContext* const _marking_context; 1216 1217 template <class T> 1218 void do_oop_work(T* p) { 1219 T o = RawAccess<>::oop_load(p); 1220 if (!CompressedOops::is_null(o)) { 1221 oop obj = CompressedOops::decode_not_null(o); 1222 if (_heap->is_concurrent_root_in_progress() && !_marking_context->is_marked(obj)) { 1223 // There may be dead oops in weak roots in concurrent root phase, do not touch them. 1224 return; 1225 } 1226 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1227 1228 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1229 if (!_bitmap->is_marked(obj)) { 1230 _bitmap->mark(obj); 1231 _oop_stack->push(obj); 1232 } 1233 } 1234 } 1235 public: 1236 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1237 _bitmap(bitmap), _oop_stack(oop_stack), _heap(ShenandoahHeap::heap()), 1238 _marking_context(_heap->marking_context()) {} 1239 void do_oop(oop* p) { do_oop_work(p); } 1240 void do_oop(narrowOop* p) { do_oop_work(p); } 1241 }; 1242 1243 /* 1244 * This is public API, used in preparation of object_iterate(). 1245 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1246 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1247 * control, we call SH::make_tlabs_parsable(). 1248 */ 1249 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1250 // No-op. 1251 } 1252 1253 /* 1254 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1255 * 1256 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1257 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1258 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1259 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1260 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1261 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1262 * wiped the bitmap in preparation for next marking). 1263 * 1264 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1265 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1266 * is allowed to report dead objects, but is not required to do so. 1267 */ 1268 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1269 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1270 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1271 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1272 return; 1273 } 1274 1275 // Reset bitmap 1276 _aux_bit_map.clear(); 1277 1278 Stack<oop,mtGC> oop_stack; 1279 1280 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects. 1281 ShenandoahHeapIterationRootScanner rp; 1282 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1283 1284 rp.roots_do(&oops); 1285 1286 // Work through the oop stack to traverse heap. 1287 while (! oop_stack.is_empty()) { 1288 oop obj = oop_stack.pop(); 1289 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1290 cl->do_object(obj); 1291 obj->oop_iterate(&oops); 1292 } 1293 1294 assert(oop_stack.is_empty(), "should be empty"); 1295 1296 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1297 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1298 } 1299 } 1300 1301 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 1302 void ShenandoahHeap::keep_alive(oop obj) { 1303 if (is_concurrent_mark_in_progress()) { 1304 ShenandoahBarrierSet::barrier_set()->enqueue(obj); 1305 } 1306 } 1307 1308 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1309 for (size_t i = 0; i < num_regions(); i++) { 1310 ShenandoahHeapRegion* current = get_region(i); 1311 blk->heap_region_do(current); 1312 } 1313 } 1314 1315 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1316 private: 1317 ShenandoahHeap* const _heap; 1318 ShenandoahHeapRegionClosure* const _blk; 1319 1320 shenandoah_padding(0); 1321 volatile size_t _index; 1322 shenandoah_padding(1); 1323 1324 public: 1325 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1326 AbstractGangTask("Parallel Region Task"), 1327 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1328 1329 void work(uint worker_id) { 1330 size_t stride = ShenandoahParallelRegionStride; 1331 1332 size_t max = _heap->num_regions(); 1333 while (_index < max) { 1334 size_t cur = Atomic::fetch_and_add(&_index, stride); 1335 size_t start = cur; 1336 size_t end = MIN2(cur + stride, max); 1337 if (start >= max) break; 1338 1339 for (size_t i = cur; i < end; i++) { 1340 ShenandoahHeapRegion* current = _heap->get_region(i); 1341 _blk->heap_region_do(current); 1342 } 1343 } 1344 } 1345 }; 1346 1347 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1348 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1349 if (num_regions() > ShenandoahParallelRegionStride) { 1350 ShenandoahParallelHeapRegionTask task(blk); 1351 workers()->run_task(&task); 1352 } else { 1353 heap_region_iterate(blk); 1354 } 1355 } 1356 1357 class ShenandoahInitMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1358 private: 1359 ShenandoahMarkingContext* const _ctx; 1360 public: 1361 ShenandoahInitMarkUpdateRegionStateClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1362 1363 void heap_region_do(ShenandoahHeapRegion* r) { 1364 if (r->is_active()) { 1365 r->clear_live_data(); 1366 _ctx->capture_top_at_mark_start(r); 1367 } else { 1368 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1369 assert(_ctx->top_at_mark_start(r) == r->top(), 1370 "Region " SIZE_FORMAT " should already have correct TAMS", r->index()); 1371 } 1372 } 1373 1374 bool is_thread_safe() { return true; } 1375 }; 1376 1377 void ShenandoahHeap::op_init_mark() { 1378 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1379 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1380 1381 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1382 assert(!marking_context()->is_complete(), "should not be complete"); 1383 assert(!has_forwarded_objects(), "No forwarded objects on this path"); 1384 1385 if (ShenandoahVerify) { 1386 verifier()->verify_before_concmark(); 1387 } 1388 1389 if (VerifyBeforeGC) { 1390 Universe::verify(); 1391 } 1392 1393 set_concurrent_mark_in_progress(true); 1394 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1395 { 1396 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1397 make_parsable(true); 1398 } 1399 1400 { 1401 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_region_states); 1402 ShenandoahInitMarkUpdateRegionStateClosure cl; 1403 parallel_heap_region_iterate(&cl); 1404 } 1405 1406 // Make above changes visible to worker threads 1407 OrderAccess::fence(); 1408 1409 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1410 1411 if (UseTLAB) { 1412 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1413 resize_tlabs(); 1414 } 1415 1416 if (ShenandoahPacing) { 1417 pacer()->setup_for_mark(); 1418 } 1419 1420 // Arm nmethods for concurrent marking. When a nmethod is about to be executed, 1421 // we need to make sure that all its metadata are marked. alternative is to remark 1422 // thread roots at final mark pause, but it can be potential latency killer. 1423 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1424 ShenandoahCodeRoots::arm_nmethods(); 1425 } 1426 } 1427 1428 void ShenandoahHeap::op_mark() { 1429 concurrent_mark()->mark_from_roots(); 1430 } 1431 1432 class ShenandoahFinalMarkUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 1433 private: 1434 ShenandoahMarkingContext* const _ctx; 1435 ShenandoahHeapLock* const _lock; 1436 1437 public: 1438 ShenandoahFinalMarkUpdateRegionStateClosure() : 1439 _ctx(ShenandoahHeap::heap()->complete_marking_context()), _lock(ShenandoahHeap::heap()->lock()) {} 1440 1441 void heap_region_do(ShenandoahHeapRegion* r) { 1442 if (r->is_active()) { 1443 // All allocations past TAMS are implicitly live, adjust the region data. 1444 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1445 HeapWord *tams = _ctx->top_at_mark_start(r); 1446 HeapWord *top = r->top(); 1447 if (top > tams) { 1448 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1449 } 1450 1451 // We are about to select the collection set, make sure it knows about 1452 // current pinning status. Also, this allows trashing more regions that 1453 // now have their pinning status dropped. 1454 if (r->is_pinned()) { 1455 if (r->pin_count() == 0) { 1456 ShenandoahHeapLocker locker(_lock); 1457 r->make_unpinned(); 1458 } 1459 } else { 1460 if (r->pin_count() > 0) { 1461 ShenandoahHeapLocker locker(_lock); 1462 r->make_pinned(); 1463 } 1464 } 1465 1466 // Remember limit for updating refs. It's guaranteed that we get no 1467 // from-space-refs written from here on. 1468 r->set_update_watermark(r->top()); 1469 } else { 1470 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index()); 1471 assert(_ctx->top_at_mark_start(r) == r->top(), 1472 "Region " SIZE_FORMAT " should have correct TAMS", r->index()); 1473 } 1474 } 1475 1476 bool is_thread_safe() { return true; } 1477 }; 1478 1479 void ShenandoahHeap::op_final_mark() { 1480 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1481 assert(!has_forwarded_objects(), "No forwarded objects on this path"); 1482 1483 // It is critical that we 1484 // evacuate roots right after finishing marking, so that we don't 1485 // get unmarked objects in the roots. 1486 1487 if (!cancelled_gc()) { 1488 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); 1489 1490 // Marking is completed, deactivate SATB barrier 1491 set_concurrent_mark_in_progress(false); 1492 mark_complete_marking_context(); 1493 1494 parallel_cleaning(false /* full gc*/); 1495 1496 if (ShenandoahVerify) { 1497 verifier()->verify_roots_no_forwarded(); 1498 } 1499 1500 { 1501 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_region_states); 1502 ShenandoahFinalMarkUpdateRegionStateClosure cl; 1503 parallel_heap_region_iterate(&cl); 1504 1505 assert_pinned_region_status(); 1506 } 1507 1508 // Force the threads to reacquire their TLABs outside the collection set. 1509 { 1510 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs); 1511 make_parsable(true); 1512 } 1513 1514 { 1515 ShenandoahGCPhase phase(ShenandoahPhaseTimings::choose_cset); 1516 ShenandoahHeapLocker locker(lock()); 1517 _collection_set->clear(); 1518 heuristics()->choose_collection_set(_collection_set); 1519 } 1520 1521 { 1522 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_rebuild_freeset); 1523 ShenandoahHeapLocker locker(lock()); 1524 _free_set->rebuild(); 1525 } 1526 1527 if (!is_degenerated_gc_in_progress()) { 1528 prepare_concurrent_roots(); 1529 prepare_concurrent_unloading(); 1530 } 1531 1532 // If collection set has candidates, start evacuation. 1533 // Otherwise, bypass the rest of the cycle. 1534 if (!collection_set()->is_empty()) { 1535 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1536 1537 if (ShenandoahVerify) { 1538 verifier()->verify_before_evacuation(); 1539 } 1540 1541 set_evacuation_in_progress(true); 1542 // From here on, we need to update references. 1543 set_has_forwarded_objects(true); 1544 1545 if (!is_degenerated_gc_in_progress()) { 1546 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1547 ShenandoahCodeRoots::arm_nmethods(); 1548 } 1549 evacuate_and_update_roots(); 1550 } 1551 1552 if (ShenandoahPacing) { 1553 pacer()->setup_for_evac(); 1554 } 1555 1556 if (ShenandoahVerify) { 1557 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None; 1558 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1559 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots); 1560 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots); 1561 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots); 1562 } 1563 1564 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1565 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots); 1566 } 1567 verifier()->verify_roots_no_forwarded_except(types); 1568 verifier()->verify_during_evacuation(); 1569 } 1570 } else { 1571 if (ShenandoahVerify) { 1572 verifier()->verify_after_concmark(); 1573 } 1574 1575 if (VerifyAfterGC) { 1576 Universe::verify(); 1577 } 1578 } 1579 1580 } else { 1581 // If this cycle was updating references, we need to keep the has_forwarded_objects 1582 // flag on, for subsequent phases to deal with it. 1583 concurrent_mark()->cancel(); 1584 set_concurrent_mark_in_progress(false); 1585 1586 if (process_references()) { 1587 // Abandon reference processing right away: pre-cleaning must have failed. 1588 ReferenceProcessor *rp = ref_processor(); 1589 rp->disable_discovery(); 1590 rp->abandon_partial_discovery(); 1591 rp->verify_no_references_recorded(); 1592 } 1593 } 1594 } 1595 1596 void ShenandoahHeap::op_conc_evac() { 1597 ShenandoahEvacuationTask task(this, _collection_set, true); 1598 workers()->run_task(&task); 1599 } 1600 1601 void ShenandoahHeap::op_stw_evac() { 1602 ShenandoahEvacuationTask task(this, _collection_set, false); 1603 workers()->run_task(&task); 1604 } 1605 1606 void ShenandoahHeap::op_updaterefs() { 1607 update_heap_references(true); 1608 } 1609 1610 void ShenandoahHeap::op_cleanup() { 1611 free_set()->recycle_trash(); 1612 } 1613 1614 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask { 1615 private: 1616 ShenandoahVMRoots<true /*concurrent*/> _vm_roots; 1617 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots; 1618 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots; 1619 ShenandoahConcurrentStringDedupRoots _dedup_roots; 1620 bool _include_weak_roots; 1621 1622 public: 1623 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) : 1624 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"), 1625 _include_weak_roots(include_weak_roots) { 1626 } 1627 1628 void work(uint worker_id) { 1629 ShenandoahEvacOOMScope oom; 1630 { 1631 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration 1632 // may race against OopStorage::release() calls. 1633 ShenandoahEvacUpdateOopStorageRootsClosure cl; 1634 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1635 1636 if (_include_weak_roots) { 1637 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1638 } 1639 } 1640 1641 { 1642 ShenandoahEvacuateUpdateRootsClosure<> cl; 1643 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong); 1644 _cld_roots.cld_do(&clds); 1645 } 1646 1647 { 1648 ShenandoahForwardedIsAliveClosure is_alive; 1649 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive; 1650 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id); 1651 } 1652 } 1653 }; 1654 1655 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure { 1656 private: 1657 ShenandoahHeap* const _heap; 1658 ShenandoahMarkingContext* const _mark_context; 1659 bool _evac_in_progress; 1660 Thread* const _thread; 1661 size_t _dead_counter; 1662 1663 public: 1664 ShenandoahEvacUpdateCleanupOopStorageRootsClosure(); 1665 void do_oop(oop* p); 1666 void do_oop(narrowOop* p); 1667 1668 size_t dead_counter() const; 1669 void reset_dead_counter(); 1670 }; 1671 1672 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() : 1673 _heap(ShenandoahHeap::heap()), 1674 _mark_context(ShenandoahHeap::heap()->marking_context()), 1675 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()), 1676 _thread(Thread::current()), 1677 _dead_counter(0) { 1678 } 1679 1680 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) { 1681 const oop obj = RawAccess<>::oop_load(p); 1682 if (!CompressedOops::is_null(obj)) { 1683 if (!_mark_context->is_marked(obj)) { 1684 shenandoah_assert_correct(p, obj); 1685 oop old = Atomic::cmpxchg(p, obj, oop(NULL)); 1686 if (obj == old) { 1687 _dead_counter ++; 1688 } 1689 } else if (_evac_in_progress && _heap->in_collection_set(obj)) { 1690 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1691 if (resolved == obj) { 1692 resolved = _heap->evacuate_object(obj, _thread); 1693 } 1694 Atomic::cmpxchg(p, obj, resolved); 1695 assert(_heap->cancelled_gc() || 1696 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved), 1697 "Sanity"); 1698 } 1699 } 1700 } 1701 1702 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) { 1703 ShouldNotReachHere(); 1704 } 1705 1706 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const { 1707 return _dead_counter; 1708 } 1709 1710 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() { 1711 _dead_counter = 0; 1712 } 1713 1714 // This task not only evacuates/updates marked weak roots, but also "NULL" 1715 // dead weak roots. 1716 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask { 1717 private: 1718 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots; 1719 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots; 1720 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots; 1721 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots; 1722 1723 public: 1724 ShenandoahConcurrentWeakRootsEvacUpdateTask() : 1725 AbstractGangTask("Shenandoah Concurrent Weak Root Task"), 1726 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots), 1727 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots), 1728 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots), 1729 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) { 1730 StringTable::reset_dead_counter(); 1731 ResolvedMethodTable::reset_dead_counter(); 1732 } 1733 1734 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() { 1735 StringTable::finish_dead_counter(); 1736 ResolvedMethodTable::finish_dead_counter(); 1737 } 1738 1739 void work(uint worker_id) { 1740 ShenandoahEvacOOMScope oom; 1741 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration 1742 // may race against OopStorage::release() calls. 1743 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl; 1744 _jni_roots.oops_do(&cl, worker_id); 1745 _vm_roots.oops_do(&cl, worker_id); 1746 1747 cl.reset_dead_counter(); 1748 _string_table_roots.oops_do(&cl, worker_id); 1749 StringTable::inc_dead_counter(cl.dead_counter()); 1750 1751 cl.reset_dead_counter(); 1752 _resolved_method_table_roots.oops_do(&cl, worker_id); 1753 ResolvedMethodTable::inc_dead_counter(cl.dead_counter()); 1754 } 1755 }; 1756 1757 void ShenandoahHeap::op_roots() { 1758 if (is_concurrent_root_in_progress()) { 1759 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1760 // Concurrent weak root processing 1761 ShenandoahConcurrentWeakRootsEvacUpdateTask task; 1762 workers()->run_task(&task); 1763 1764 _unloader.unload(); 1765 } 1766 1767 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1768 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 1769 workers()->run_task(&task); 1770 } 1771 } 1772 1773 set_concurrent_root_in_progress(false); 1774 } 1775 1776 void ShenandoahHeap::op_reset() { 1777 if (ShenandoahPacing) { 1778 pacer()->setup_for_reset(); 1779 } 1780 reset_mark_bitmap(); 1781 } 1782 1783 void ShenandoahHeap::op_preclean() { 1784 if (ShenandoahPacing) { 1785 pacer()->setup_for_preclean(); 1786 } 1787 concurrent_mark()->preclean_weak_refs(); 1788 } 1789 1790 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1791 ShenandoahMetricsSnapshot metrics; 1792 metrics.snap_before(); 1793 1794 full_gc()->do_it(cause); 1795 if (UseTLAB) { 1796 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs); 1797 resize_all_tlabs(); 1798 } 1799 1800 metrics.snap_after(); 1801 1802 if (metrics.is_good_progress()) { 1803 _progress_last_gc.set(); 1804 } else { 1805 // Nothing to do. Tell the allocation path that we have failed to make 1806 // progress, and it can finally fail. 1807 _progress_last_gc.unset(); 1808 } 1809 } 1810 1811 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1812 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1813 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1814 // some phase, we have to upgrade the Degenerate GC to Full GC. 1815 1816 clear_cancelled_gc(); 1817 1818 ShenandoahMetricsSnapshot metrics; 1819 metrics.snap_before(); 1820 1821 switch (point) { 1822 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1823 // but enters it at different points, depending on which concurrent phase had 1824 // degenerated. 1825 1826 case _degenerated_outside_cycle: 1827 // We have degenerated from outside the cycle, which means something is bad with 1828 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1829 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1830 // we can do the most aggressive degen cycle, which includes processing references and 1831 // class unloading, unless those features are explicitly disabled. 1832 // 1833 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1834 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1835 set_process_references(heuristics()->can_process_references()); 1836 set_unload_classes(heuristics()->can_unload_classes()); 1837 1838 op_reset(); 1839 1840 op_init_mark(); 1841 if (cancelled_gc()) { 1842 op_degenerated_fail(); 1843 return; 1844 } 1845 1846 case _degenerated_mark: 1847 op_final_mark(); 1848 if (cancelled_gc()) { 1849 op_degenerated_fail(); 1850 return; 1851 } 1852 1853 if (!has_forwarded_objects() && ShenandoahConcurrentRoots::can_do_concurrent_class_unloading()) { 1854 // Disarm nmethods that armed for concurrent mark. On normal cycle, it would 1855 // be disarmed while conc-roots phase is running. 1856 // TODO: Call op_conc_roots() here instead 1857 ShenandoahCodeRoots::disarm_nmethods(); 1858 } 1859 1860 op_cleanup(); 1861 1862 case _degenerated_evac: 1863 // If heuristics thinks we should do the cycle, this flag would be set, 1864 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1865 if (is_evacuation_in_progress()) { 1866 1867 // Degeneration under oom-evac protocol might have left some objects in 1868 // collection set un-evacuated. Restart evacuation from the beginning to 1869 // capture all objects. For all the objects that are already evacuated, 1870 // it would be a simple check, which is supposed to be fast. This is also 1871 // safe to do even without degeneration, as CSet iterator is at beginning 1872 // in preparation for evacuation anyway. 1873 // 1874 // Before doing that, we need to make sure we never had any cset-pinned 1875 // regions. This may happen if allocation failure happened when evacuating 1876 // the about-to-be-pinned object, oom-evac protocol left the object in 1877 // the collection set, and then the pin reached the cset region. If we continue 1878 // the cycle here, we would trash the cset and alive objects in it. To avoid 1879 // it, we fail degeneration right away and slide into Full GC to recover. 1880 1881 { 1882 sync_pinned_region_status(); 1883 collection_set()->clear_current_index(); 1884 1885 ShenandoahHeapRegion* r; 1886 while ((r = collection_set()->next()) != NULL) { 1887 if (r->is_pinned()) { 1888 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1889 op_degenerated_fail(); 1890 return; 1891 } 1892 } 1893 1894 collection_set()->clear_current_index(); 1895 } 1896 1897 op_stw_evac(); 1898 if (cancelled_gc()) { 1899 op_degenerated_fail(); 1900 return; 1901 } 1902 } 1903 1904 // If heuristics thinks we should do the cycle, this flag would be set, 1905 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1906 if (has_forwarded_objects()) { 1907 op_init_updaterefs(); 1908 if (cancelled_gc()) { 1909 op_degenerated_fail(); 1910 return; 1911 } 1912 } 1913 1914 case _degenerated_updaterefs: 1915 if (has_forwarded_objects()) { 1916 op_final_updaterefs(); 1917 if (cancelled_gc()) { 1918 op_degenerated_fail(); 1919 return; 1920 } 1921 } 1922 1923 op_cleanup(); 1924 break; 1925 1926 default: 1927 ShouldNotReachHere(); 1928 } 1929 1930 if (ShenandoahVerify) { 1931 verifier()->verify_after_degenerated(); 1932 } 1933 1934 if (VerifyAfterGC) { 1935 Universe::verify(); 1936 } 1937 1938 metrics.snap_after(); 1939 1940 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 1941 // because that probably means the heap is overloaded and/or fragmented. 1942 if (!metrics.is_good_progress()) { 1943 _progress_last_gc.unset(); 1944 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1945 op_degenerated_futile(); 1946 } else { 1947 _progress_last_gc.set(); 1948 } 1949 } 1950 1951 void ShenandoahHeap::op_degenerated_fail() { 1952 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 1953 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1954 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1955 } 1956 1957 void ShenandoahHeap::op_degenerated_futile() { 1958 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1959 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1960 } 1961 1962 void ShenandoahHeap::force_satb_flush_all_threads() { 1963 if (!is_concurrent_mark_in_progress()) { 1964 // No need to flush SATBs 1965 return; 1966 } 1967 1968 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1969 ShenandoahThreadLocalData::set_force_satb_flush(t, true); 1970 } 1971 // The threads are not "acquiring" their thread-local data, but it does not 1972 // hurt to "release" the updates here anyway. 1973 OrderAccess::fence(); 1974 } 1975 1976 void ShenandoahHeap::set_gc_state_all_threads(char state) { 1977 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1978 ShenandoahThreadLocalData::set_gc_state(t, state); 1979 } 1980 } 1981 1982 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1983 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1984 _gc_state.set_cond(mask, value); 1985 set_gc_state_all_threads(_gc_state.raw_value()); 1986 } 1987 1988 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1989 if (has_forwarded_objects()) { 1990 set_gc_state_mask(MARKING | UPDATEREFS, in_progress); 1991 } else { 1992 set_gc_state_mask(MARKING, in_progress); 1993 } 1994 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1995 } 1996 1997 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1998 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1999 set_gc_state_mask(EVACUATION, in_progress); 2000 } 2001 2002 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) { 2003 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?"); 2004 if (in_progress) { 2005 _concurrent_root_in_progress.set(); 2006 } else { 2007 _concurrent_root_in_progress.unset(); 2008 } 2009 } 2010 2011 void ShenandoahHeap::ref_processing_init() { 2012 assert(_max_workers > 0, "Sanity"); 2013 2014 _ref_processor = 2015 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery 2016 ParallelRefProcEnabled, // MT processing 2017 _max_workers, // Degree of MT processing 2018 true, // MT discovery 2019 _max_workers, // Degree of MT discovery 2020 false, // Reference discovery is not atomic 2021 NULL, // No closure, should be installed before use 2022 true); // Scale worker threads 2023 2024 shenandoah_assert_rp_isalive_not_installed(); 2025 } 2026 2027 GCTracer* ShenandoahHeap::tracer() { 2028 return shenandoah_policy()->tracer(); 2029 } 2030 2031 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 2032 return _free_set->used(); 2033 } 2034 2035 bool ShenandoahHeap::try_cancel_gc() { 2036 while (true) { 2037 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 2038 if (prev == CANCELLABLE) return true; 2039 else if (prev == CANCELLED) return false; 2040 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 2041 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 2042 if (Thread::current()->is_Java_thread()) { 2043 // We need to provide a safepoint here, otherwise we might 2044 // spin forever if a SP is pending. 2045 ThreadBlockInVM sp(JavaThread::current()); 2046 SpinPause(); 2047 } 2048 } 2049 } 2050 2051 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 2052 if (try_cancel_gc()) { 2053 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 2054 log_info(gc)("%s", msg.buffer()); 2055 Events::log(Thread::current(), "%s", msg.buffer()); 2056 } 2057 } 2058 2059 uint ShenandoahHeap::max_workers() { 2060 return _max_workers; 2061 } 2062 2063 void ShenandoahHeap::stop() { 2064 // The shutdown sequence should be able to terminate when GC is running. 2065 2066 // Step 0. Notify policy to disable event recording. 2067 _shenandoah_policy->record_shutdown(); 2068 2069 // Step 1. Notify control thread that we are in shutdown. 2070 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 2071 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 2072 control_thread()->prepare_for_graceful_shutdown(); 2073 2074 // Step 2. Notify GC workers that we are cancelling GC. 2075 cancel_gc(GCCause::_shenandoah_stop_vm); 2076 2077 // Step 3. Wait until GC worker exits normally. 2078 control_thread()->stop(); 2079 2080 // Step 4. Stop String Dedup thread if it is active 2081 if (ShenandoahStringDedup::is_enabled()) { 2082 ShenandoahStringDedup::stop(); 2083 } 2084 } 2085 2086 void ShenandoahHeap::stw_unload_classes(bool full_gc) { 2087 if (!unload_classes()) return; 2088 bool purged_class; 2089 2090 // Unload classes and purge SystemDictionary. 2091 { 2092 ShenandoahGCPhase phase(full_gc ? 2093 ShenandoahPhaseTimings::full_gc_purge_class_unload : 2094 ShenandoahPhaseTimings::purge_class_unload); 2095 purged_class = SystemDictionary::do_unloading(gc_timer()); 2096 } 2097 2098 { 2099 ShenandoahGCPhase phase(full_gc ? 2100 ShenandoahPhaseTimings::full_gc_purge_par : 2101 ShenandoahPhaseTimings::purge_par); 2102 ShenandoahIsAliveSelector is_alive; 2103 uint num_workers = _workers->active_workers(); 2104 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class); 2105 _workers->run_task(&unlink_task); 2106 } 2107 2108 { 2109 ShenandoahGCPhase phase(full_gc ? 2110 ShenandoahPhaseTimings::full_gc_purge_cldg : 2111 ShenandoahPhaseTimings::purge_cldg); 2112 ClassLoaderDataGraph::purge(); 2113 } 2114 // Resize and verify metaspace 2115 MetaspaceGC::compute_new_size(); 2116 MetaspaceUtils::verify_metrics(); 2117 } 2118 2119 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs), 2120 // so they should not have forwarded oops. 2121 // However, we do need to "null" dead oops in the roots, if can not be done 2122 // in concurrent cycles. 2123 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) { 2124 ShenandoahGCPhase root_phase(full_gc ? 2125 ShenandoahPhaseTimings::full_gc_purge : 2126 ShenandoahPhaseTimings::purge); 2127 uint num_workers = _workers->active_workers(); 2128 ShenandoahPhaseTimings::Phase timing_phase = full_gc ? 2129 ShenandoahPhaseTimings::full_gc_purge_par : 2130 ShenandoahPhaseTimings::purge_par; 2131 ShenandoahGCPhase phase(timing_phase); 2132 ShenandoahGCWorkerPhase worker_phase(timing_phase); 2133 2134 // Cleanup weak roots 2135 if (has_forwarded_objects()) { 2136 ShenandoahForwardedIsAliveClosure is_alive; 2137 ShenandoahUpdateRefsClosure keep_alive; 2138 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure> 2139 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2140 _workers->run_task(&cleaning_task); 2141 } else { 2142 ShenandoahIsAliveClosure is_alive; 2143 #ifdef ASSERT 2144 ShenandoahAssertNotForwardedClosure verify_cl; 2145 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure> 2146 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2147 #else 2148 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure> 2149 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2150 #endif 2151 _workers->run_task(&cleaning_task); 2152 } 2153 } 2154 2155 void ShenandoahHeap::parallel_cleaning(bool full_gc) { 2156 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2157 stw_process_weak_roots(full_gc); 2158 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2159 stw_unload_classes(full_gc); 2160 } 2161 } 2162 2163 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 2164 set_gc_state_mask(HAS_FORWARDED, cond); 2165 } 2166 2167 void ShenandoahHeap::set_process_references(bool pr) { 2168 _process_references.set_cond(pr); 2169 } 2170 2171 void ShenandoahHeap::set_unload_classes(bool uc) { 2172 _unload_classes.set_cond(uc); 2173 } 2174 2175 bool ShenandoahHeap::process_references() const { 2176 return _process_references.is_set(); 2177 } 2178 2179 bool ShenandoahHeap::unload_classes() const { 2180 return _unload_classes.is_set(); 2181 } 2182 2183 address ShenandoahHeap::in_cset_fast_test_addr() { 2184 ShenandoahHeap* heap = ShenandoahHeap::heap(); 2185 assert(heap->collection_set() != NULL, "Sanity"); 2186 return (address) heap->collection_set()->biased_map_address(); 2187 } 2188 2189 address ShenandoahHeap::cancelled_gc_addr() { 2190 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 2191 } 2192 2193 address ShenandoahHeap::gc_state_addr() { 2194 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 2195 } 2196 2197 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 2198 return Atomic::load_acquire(&_bytes_allocated_since_gc_start); 2199 } 2200 2201 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 2202 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 2203 } 2204 2205 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 2206 _degenerated_gc_in_progress.set_cond(in_progress); 2207 } 2208 2209 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 2210 _full_gc_in_progress.set_cond(in_progress); 2211 } 2212 2213 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 2214 assert (is_full_gc_in_progress(), "should be"); 2215 _full_gc_move_in_progress.set_cond(in_progress); 2216 } 2217 2218 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 2219 set_gc_state_mask(UPDATEREFS, in_progress); 2220 } 2221 2222 void ShenandoahHeap::register_nmethod(nmethod* nm) { 2223 ShenandoahCodeRoots::register_nmethod(nm); 2224 } 2225 2226 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 2227 ShenandoahCodeRoots::unregister_nmethod(nm); 2228 } 2229 2230 void ShenandoahHeap::flush_nmethod(nmethod* nm) { 2231 ShenandoahCodeRoots::flush_nmethod(nm); 2232 } 2233 2234 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 2235 heap_region_containing(o)->record_pin(); 2236 return o; 2237 } 2238 2239 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 2240 heap_region_containing(o)->record_unpin(); 2241 } 2242 2243 void ShenandoahHeap::sync_pinned_region_status() { 2244 ShenandoahHeapLocker locker(lock()); 2245 2246 for (size_t i = 0; i < num_regions(); i++) { 2247 ShenandoahHeapRegion *r = get_region(i); 2248 if (r->is_active()) { 2249 if (r->is_pinned()) { 2250 if (r->pin_count() == 0) { 2251 r->make_unpinned(); 2252 } 2253 } else { 2254 if (r->pin_count() > 0) { 2255 r->make_pinned(); 2256 } 2257 } 2258 } 2259 } 2260 2261 assert_pinned_region_status(); 2262 } 2263 2264 #ifdef ASSERT 2265 void ShenandoahHeap::assert_pinned_region_status() { 2266 for (size_t i = 0; i < num_regions(); i++) { 2267 ShenandoahHeapRegion* r = get_region(i); 2268 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 2269 "Region " SIZE_FORMAT " pinning status is inconsistent", i); 2270 } 2271 } 2272 #endif 2273 2274 GCTimer* ShenandoahHeap::gc_timer() const { 2275 return _gc_timer; 2276 } 2277 2278 void ShenandoahHeap::prepare_concurrent_roots() { 2279 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2280 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 2281 set_concurrent_root_in_progress(true); 2282 } 2283 } 2284 2285 void ShenandoahHeap::prepare_concurrent_unloading() { 2286 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2287 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2288 _unloader.prepare(); 2289 } 2290 } 2291 2292 void ShenandoahHeap::finish_concurrent_unloading() { 2293 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2294 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2295 _unloader.finish(); 2296 } 2297 } 2298 2299 #ifdef ASSERT 2300 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 2301 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 2302 2303 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 2304 if (UseDynamicNumberOfGCThreads) { 2305 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 2306 } else { 2307 // Use ParallelGCThreads inside safepoints 2308 assert(nworkers == ParallelGCThreads, "Use ParallelGCThreads within safepoints"); 2309 } 2310 } else { 2311 if (UseDynamicNumberOfGCThreads) { 2312 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2313 } else { 2314 // Use ConcGCThreads outside safepoints 2315 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2316 } 2317 } 2318 } 2319 #endif 2320 2321 ShenandoahVerifier* ShenandoahHeap::verifier() { 2322 guarantee(ShenandoahVerify, "Should be enabled"); 2323 assert (_verifier != NULL, "sanity"); 2324 return _verifier; 2325 } 2326 2327 template<class T> 2328 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2329 private: 2330 T cl; 2331 ShenandoahHeap* _heap; 2332 ShenandoahRegionIterator* _regions; 2333 bool _concurrent; 2334 public: 2335 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2336 AbstractGangTask("Concurrent Update References Task"), 2337 cl(T()), 2338 _heap(ShenandoahHeap::heap()), 2339 _regions(regions), 2340 _concurrent(concurrent) { 2341 } 2342 2343 void work(uint worker_id) { 2344 if (_concurrent) { 2345 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2346 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2347 do_work(); 2348 } else { 2349 ShenandoahParallelWorkerSession worker_session(worker_id); 2350 do_work(); 2351 } 2352 } 2353 2354 private: 2355 void do_work() { 2356 ShenandoahHeapRegion* r = _regions->next(); 2357 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2358 while (r != NULL) { 2359 HeapWord* update_watermark = r->get_update_watermark(); 2360 assert (update_watermark >= r->bottom(), "sanity"); 2361 if (r->is_active() && !r->is_cset()) { 2362 _heap->marked_object_oop_iterate(r, &cl, update_watermark); 2363 } 2364 if (ShenandoahPacing) { 2365 _heap->pacer()->report_updaterefs(pointer_delta(update_watermark, r->bottom())); 2366 } 2367 if (_heap->check_cancelled_gc_and_yield(_concurrent)) { 2368 return; 2369 } 2370 r = _regions->next(); 2371 } 2372 } 2373 }; 2374 2375 void ShenandoahHeap::update_heap_references(bool concurrent) { 2376 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent); 2377 workers()->run_task(&task); 2378 } 2379 2380 void ShenandoahHeap::op_init_updaterefs() { 2381 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2382 2383 set_evacuation_in_progress(false); 2384 2385 { 2386 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs); 2387 retire_and_reset_gclabs(); 2388 } 2389 2390 if (ShenandoahVerify) { 2391 if (!is_degenerated_gc_in_progress()) { 2392 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots); 2393 } 2394 verifier()->verify_before_updaterefs(); 2395 } 2396 2397 set_update_refs_in_progress(true); 2398 2399 { 2400 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare); 2401 2402 make_parsable(true); 2403 2404 // Reset iterator. 2405 _update_refs_iterator.reset(); 2406 } 2407 2408 if (ShenandoahPacing) { 2409 pacer()->setup_for_updaterefs(); 2410 } 2411 } 2412 2413 class ShenandoahFinalUpdateRefsUpdateRegionStateClosure : public ShenandoahHeapRegionClosure { 2414 private: 2415 ShenandoahHeapLock* const _lock; 2416 2417 public: 2418 ShenandoahFinalUpdateRefsUpdateRegionStateClosure() : _lock(ShenandoahHeap::heap()->lock()) {} 2419 2420 void heap_region_do(ShenandoahHeapRegion* r) { 2421 // Drop unnecessary "pinned" state from regions that does not have CP marks 2422 // anymore, as this would allow trashing them. 2423 2424 if (r->is_active()) { 2425 if (r->is_pinned()) { 2426 if (r->pin_count() == 0) { 2427 ShenandoahHeapLocker locker(_lock); 2428 r->make_unpinned(); 2429 } 2430 } else { 2431 if (r->pin_count() > 0) { 2432 ShenandoahHeapLocker locker(_lock); 2433 r->make_pinned(); 2434 } 2435 } 2436 } 2437 } 2438 2439 bool is_thread_safe() { return true; } 2440 }; 2441 2442 void ShenandoahHeap::op_final_updaterefs() { 2443 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2444 2445 finish_concurrent_unloading(); 2446 2447 // Check if there is left-over work, and finish it 2448 if (_update_refs_iterator.has_next()) { 2449 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work); 2450 2451 // Finish updating references where we left off. 2452 clear_cancelled_gc(); 2453 update_heap_references(false); 2454 } 2455 2456 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2457 // everything. On degenerated paths, cancelled gc would not be set anyway. 2458 if (cancelled_gc()) { 2459 clear_cancelled_gc(); 2460 } 2461 assert(!cancelled_gc(), "Should have been done right before"); 2462 2463 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) { 2464 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots); 2465 } 2466 2467 if (is_degenerated_gc_in_progress()) { 2468 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 2469 } else { 2470 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots); 2471 } 2472 2473 // Has to be done before cset is clear 2474 if (ShenandoahVerify) { 2475 verifier()->verify_roots_in_to_space(); 2476 } 2477 2478 { 2479 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_update_region_states); 2480 ShenandoahFinalUpdateRefsUpdateRegionStateClosure cl; 2481 parallel_heap_region_iterate(&cl); 2482 2483 assert_pinned_region_status(); 2484 } 2485 2486 { 2487 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset); 2488 trash_cset_regions(); 2489 } 2490 2491 set_has_forwarded_objects(false); 2492 set_update_refs_in_progress(false); 2493 2494 if (ShenandoahVerify) { 2495 verifier()->verify_after_updaterefs(); 2496 } 2497 2498 if (VerifyAfterGC) { 2499 Universe::verify(); 2500 } 2501 2502 { 2503 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_rebuild_freeset); 2504 ShenandoahHeapLocker locker(lock()); 2505 _free_set->rebuild(); 2506 } 2507 } 2508 2509 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2510 print_on(st); 2511 print_heap_regions_on(st); 2512 } 2513 2514 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2515 size_t slice = r->index() / _bitmap_regions_per_slice; 2516 2517 size_t regions_from = _bitmap_regions_per_slice * slice; 2518 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2519 for (size_t g = regions_from; g < regions_to; g++) { 2520 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2521 if (skip_self && g == r->index()) continue; 2522 if (get_region(g)->is_committed()) { 2523 return true; 2524 } 2525 } 2526 return false; 2527 } 2528 2529 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2530 shenandoah_assert_heaplocked(); 2531 2532 // Bitmaps in special regions do not need commits 2533 if (_bitmap_region_special) { 2534 return true; 2535 } 2536 2537 if (is_bitmap_slice_committed(r, true)) { 2538 // Some other region from the group is already committed, meaning the bitmap 2539 // slice is already committed, we exit right away. 2540 return true; 2541 } 2542 2543 // Commit the bitmap slice: 2544 size_t slice = r->index() / _bitmap_regions_per_slice; 2545 size_t off = _bitmap_bytes_per_slice * slice; 2546 size_t len = _bitmap_bytes_per_slice; 2547 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2548 return false; 2549 } 2550 return true; 2551 } 2552 2553 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2554 shenandoah_assert_heaplocked(); 2555 2556 // Bitmaps in special regions do not need uncommits 2557 if (_bitmap_region_special) { 2558 return true; 2559 } 2560 2561 if (is_bitmap_slice_committed(r, true)) { 2562 // Some other region from the group is still committed, meaning the bitmap 2563 // slice is should stay committed, exit right away. 2564 return true; 2565 } 2566 2567 // Uncommit the bitmap slice: 2568 size_t slice = r->index() / _bitmap_regions_per_slice; 2569 size_t off = _bitmap_bytes_per_slice * slice; 2570 size_t len = _bitmap_bytes_per_slice; 2571 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2572 return false; 2573 } 2574 return true; 2575 } 2576 2577 void ShenandoahHeap::safepoint_synchronize_begin() { 2578 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2579 SuspendibleThreadSet::synchronize(); 2580 } 2581 } 2582 2583 void ShenandoahHeap::safepoint_synchronize_end() { 2584 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2585 SuspendibleThreadSet::desynchronize(); 2586 } 2587 } 2588 2589 void ShenandoahHeap::vmop_entry_init_mark() { 2590 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2591 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2592 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2593 2594 try_inject_alloc_failure(); 2595 VM_ShenandoahInitMark op; 2596 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2597 } 2598 2599 void ShenandoahHeap::vmop_entry_final_mark() { 2600 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2601 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2602 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2603 2604 try_inject_alloc_failure(); 2605 VM_ShenandoahFinalMarkStartEvac op; 2606 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2607 } 2608 2609 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2610 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2611 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2612 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2613 2614 try_inject_alloc_failure(); 2615 VM_ShenandoahInitUpdateRefs op; 2616 VMThread::execute(&op); 2617 } 2618 2619 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2620 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2621 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2622 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2623 2624 try_inject_alloc_failure(); 2625 VM_ShenandoahFinalUpdateRefs op; 2626 VMThread::execute(&op); 2627 } 2628 2629 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2630 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2631 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2632 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2633 2634 try_inject_alloc_failure(); 2635 VM_ShenandoahFullGC op(cause); 2636 VMThread::execute(&op); 2637 } 2638 2639 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2640 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2641 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2642 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2643 2644 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2645 VMThread::execute(°enerated_gc); 2646 } 2647 2648 void ShenandoahHeap::entry_init_mark() { 2649 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2650 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2651 const char* msg = init_mark_event_message(); 2652 GCTraceTime(Info, gc) time(msg, gc_timer()); 2653 EventMark em("%s", msg); 2654 2655 ShenandoahWorkerScope scope(workers(), 2656 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2657 "init marking"); 2658 2659 op_init_mark(); 2660 } 2661 2662 void ShenandoahHeap::entry_final_mark() { 2663 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2664 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2665 const char* msg = final_mark_event_message(); 2666 GCTraceTime(Info, gc) time(msg, gc_timer()); 2667 EventMark em("%s", msg); 2668 2669 ShenandoahWorkerScope scope(workers(), 2670 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2671 "final marking"); 2672 2673 op_final_mark(); 2674 } 2675 2676 void ShenandoahHeap::entry_init_updaterefs() { 2677 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2678 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2679 2680 static const char* msg = "Pause Init Update Refs"; 2681 GCTraceTime(Info, gc) time(msg, gc_timer()); 2682 EventMark em("%s", msg); 2683 2684 // No workers used in this phase, no setup required 2685 2686 op_init_updaterefs(); 2687 } 2688 2689 void ShenandoahHeap::entry_final_updaterefs() { 2690 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2691 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2692 2693 static const char* msg = "Pause Final Update Refs"; 2694 GCTraceTime(Info, gc) time(msg, gc_timer()); 2695 EventMark em("%s", msg); 2696 2697 ShenandoahWorkerScope scope(workers(), 2698 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2699 "final reference update"); 2700 2701 op_final_updaterefs(); 2702 } 2703 2704 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2705 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2706 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2707 2708 static const char* msg = "Pause Full"; 2709 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true); 2710 EventMark em("%s", msg); 2711 2712 ShenandoahWorkerScope scope(workers(), 2713 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2714 "full gc"); 2715 2716 op_full(cause); 2717 } 2718 2719 void ShenandoahHeap::entry_degenerated(int point) { 2720 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2721 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2722 2723 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2724 const char* msg = degen_event_message(dpoint); 2725 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2726 EventMark em("%s", msg); 2727 2728 ShenandoahWorkerScope scope(workers(), 2729 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2730 "stw degenerated gc"); 2731 2732 set_degenerated_gc_in_progress(true); 2733 op_degenerated(dpoint); 2734 set_degenerated_gc_in_progress(false); 2735 } 2736 2737 void ShenandoahHeap::entry_mark() { 2738 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2739 2740 const char* msg = conc_mark_event_message(); 2741 GCTraceTime(Info, gc) time(msg); 2742 EventMark em("%s", msg); 2743 2744 ShenandoahWorkerScope scope(workers(), 2745 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2746 "concurrent marking"); 2747 2748 try_inject_alloc_failure(); 2749 op_mark(); 2750 } 2751 2752 void ShenandoahHeap::entry_evac() { 2753 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2754 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2755 2756 static const char* msg = "Concurrent evacuation"; 2757 GCTraceTime(Info, gc) time(msg); 2758 EventMark em("%s", msg); 2759 2760 ShenandoahWorkerScope scope(workers(), 2761 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2762 "concurrent evacuation"); 2763 2764 try_inject_alloc_failure(); 2765 op_conc_evac(); 2766 } 2767 2768 void ShenandoahHeap::entry_updaterefs() { 2769 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2770 2771 static const char* msg = "Concurrent update references"; 2772 GCTraceTime(Info, gc) time(msg); 2773 EventMark em("%s", msg); 2774 2775 ShenandoahWorkerScope scope(workers(), 2776 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2777 "concurrent reference update"); 2778 2779 try_inject_alloc_failure(); 2780 op_updaterefs(); 2781 } 2782 2783 void ShenandoahHeap::entry_roots() { 2784 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots); 2785 2786 static const char* msg = "Concurrent roots processing"; 2787 GCTraceTime(Info, gc) time(msg); 2788 EventMark em("%s", msg); 2789 2790 ShenandoahWorkerScope scope(workers(), 2791 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(), 2792 "concurrent root processing"); 2793 2794 try_inject_alloc_failure(); 2795 op_roots(); 2796 } 2797 2798 void ShenandoahHeap::entry_cleanup() { 2799 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2800 2801 static const char* msg = "Concurrent cleanup"; 2802 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2803 EventMark em("%s", msg); 2804 2805 // This phase does not use workers, no need for setup 2806 2807 try_inject_alloc_failure(); 2808 op_cleanup(); 2809 } 2810 2811 void ShenandoahHeap::entry_reset() { 2812 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2813 2814 static const char* msg = "Concurrent reset"; 2815 GCTraceTime(Info, gc) time(msg); 2816 EventMark em("%s", msg); 2817 2818 ShenandoahWorkerScope scope(workers(), 2819 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2820 "concurrent reset"); 2821 2822 try_inject_alloc_failure(); 2823 op_reset(); 2824 } 2825 2826 void ShenandoahHeap::entry_preclean() { 2827 if (ShenandoahPreclean && process_references()) { 2828 static const char* msg = "Concurrent precleaning"; 2829 GCTraceTime(Info, gc) time(msg); 2830 EventMark em("%s", msg); 2831 2832 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2833 2834 ShenandoahWorkerScope scope(workers(), 2835 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2836 "concurrent preclean", 2837 /* check_workers = */ false); 2838 2839 try_inject_alloc_failure(); 2840 op_preclean(); 2841 } 2842 } 2843 2844 void ShenandoahHeap::entry_uncommit(double shrink_before) { 2845 static const char *msg = "Concurrent uncommit"; 2846 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2847 EventMark em("%s", msg); 2848 2849 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 2850 2851 op_uncommit(shrink_before); 2852 } 2853 2854 void ShenandoahHeap::try_inject_alloc_failure() { 2855 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2856 _inject_alloc_failure.set(); 2857 os::naked_short_sleep(1); 2858 if (cancelled_gc()) { 2859 log_info(gc)("Allocation failure was successfully injected"); 2860 } 2861 } 2862 } 2863 2864 bool ShenandoahHeap::should_inject_alloc_failure() { 2865 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2866 } 2867 2868 void ShenandoahHeap::initialize_serviceability() { 2869 _memory_pool = new ShenandoahMemoryPool(this); 2870 _cycle_memory_manager.add_pool(_memory_pool); 2871 _stw_memory_manager.add_pool(_memory_pool); 2872 } 2873 2874 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 2875 GrowableArray<GCMemoryManager*> memory_managers(2); 2876 memory_managers.append(&_cycle_memory_manager); 2877 memory_managers.append(&_stw_memory_manager); 2878 return memory_managers; 2879 } 2880 2881 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 2882 GrowableArray<MemoryPool*> memory_pools(1); 2883 memory_pools.append(_memory_pool); 2884 return memory_pools; 2885 } 2886 2887 MemoryUsage ShenandoahHeap::memory_usage() { 2888 return _memory_pool->get_memory_usage(); 2889 } 2890 2891 void ShenandoahHeap::enter_evacuation() { 2892 _oom_evac_handler.enter_evacuation(); 2893 } 2894 2895 void ShenandoahHeap::leave_evacuation() { 2896 _oom_evac_handler.leave_evacuation(); 2897 } 2898 2899 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2900 _heap(ShenandoahHeap::heap()), 2901 _index(0) {} 2902 2903 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2904 _heap(heap), 2905 _index(0) {} 2906 2907 void ShenandoahRegionIterator::reset() { 2908 _index = 0; 2909 } 2910 2911 bool ShenandoahRegionIterator::has_next() const { 2912 return _index < _heap->num_regions(); 2913 } 2914 2915 char ShenandoahHeap::gc_state() const { 2916 return _gc_state.raw_value(); 2917 } 2918 2919 void ShenandoahHeap::deduplicate_string(oop str) { 2920 assert(java_lang_String::is_instance(str), "invariant"); 2921 2922 if (ShenandoahStringDedup::is_enabled()) { 2923 ShenandoahStringDedup::deduplicate(str); 2924 } 2925 } 2926 2927 const char* ShenandoahHeap::init_mark_event_message() const { 2928 assert(!has_forwarded_objects(), "Should not have forwarded objects here"); 2929 2930 bool proc_refs = process_references(); 2931 bool unload_cls = unload_classes(); 2932 2933 if (proc_refs && unload_cls) { 2934 return "Pause Init Mark (process weakrefs) (unload classes)"; 2935 } else if (proc_refs) { 2936 return "Pause Init Mark (process weakrefs)"; 2937 } else if (unload_cls) { 2938 return "Pause Init Mark (unload classes)"; 2939 } else { 2940 return "Pause Init Mark"; 2941 } 2942 } 2943 2944 const char* ShenandoahHeap::final_mark_event_message() const { 2945 assert(!has_forwarded_objects(), "Should not have forwarded objects here"); 2946 2947 bool proc_refs = process_references(); 2948 bool unload_cls = unload_classes(); 2949 2950 if (proc_refs && unload_cls) { 2951 return "Pause Final Mark (process weakrefs) (unload classes)"; 2952 } else if (proc_refs) { 2953 return "Pause Final Mark (process weakrefs)"; 2954 } else if (unload_cls) { 2955 return "Pause Final Mark (unload classes)"; 2956 } else { 2957 return "Pause Final Mark"; 2958 } 2959 } 2960 2961 const char* ShenandoahHeap::conc_mark_event_message() const { 2962 assert(!has_forwarded_objects(), "Should not have forwarded objects here"); 2963 2964 bool proc_refs = process_references(); 2965 bool unload_cls = unload_classes(); 2966 2967 if (proc_refs && unload_cls) { 2968 return "Concurrent marking (process weakrefs) (unload classes)"; 2969 } else if (proc_refs) { 2970 return "Concurrent marking (process weakrefs)"; 2971 } else if (unload_cls) { 2972 return "Concurrent marking (unload classes)"; 2973 } else { 2974 return "Concurrent marking"; 2975 } 2976 } 2977 2978 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 2979 switch (point) { 2980 case _degenerated_unset: 2981 return "Pause Degenerated GC (<UNSET>)"; 2982 case _degenerated_outside_cycle: 2983 return "Pause Degenerated GC (Outside of Cycle)"; 2984 case _degenerated_mark: 2985 return "Pause Degenerated GC (Mark)"; 2986 case _degenerated_evac: 2987 return "Pause Degenerated GC (Evacuation)"; 2988 case _degenerated_updaterefs: 2989 return "Pause Degenerated GC (Update Refs)"; 2990 default: 2991 ShouldNotReachHere(); 2992 return "ERROR"; 2993 } 2994 } 2995 2996 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2997 #ifdef ASSERT 2998 assert(_liveness_cache != NULL, "sanity"); 2999 assert(worker_id < _max_workers, "sanity"); 3000 for (uint i = 0; i < num_regions(); i++) { 3001 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 3002 } 3003 #endif 3004 return _liveness_cache[worker_id]; 3005 } 3006 3007 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 3008 assert(worker_id < _max_workers, "sanity"); 3009 assert(_liveness_cache != NULL, "sanity"); 3010 jushort* ld = _liveness_cache[worker_id]; 3011 for (uint i = 0; i < num_regions(); i++) { 3012 ShenandoahHeapRegion* r = get_region(i); 3013 jushort live = ld[i]; 3014 if (live > 0) { 3015 r->increase_live_data_gc_words(live); 3016 ld[i] = 0; 3017 } 3018 } 3019 }