1 /* 2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "memory/allocation.hpp" 26 #include "memory/universe.hpp" 27 28 #include "gc/shared/gcArguments.hpp" 29 #include "gc/shared/gcTimer.hpp" 30 #include "gc/shared/gcTraceTime.inline.hpp" 31 #include "gc/shared/locationPrinter.inline.hpp" 32 #include "gc/shared/memAllocator.hpp" 33 #include "gc/shared/plab.hpp" 34 35 #include "gc/shenandoah/shenandoahAllocTracker.hpp" 36 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 37 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 38 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 39 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 40 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" 41 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp" 42 #include "gc/shenandoah/shenandoahControlThread.hpp" 43 #include "gc/shenandoah/shenandoahFreeSet.hpp" 44 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 45 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 46 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 47 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 48 #include "gc/shenandoah/shenandoahMarkCompact.hpp" 49 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 50 #include "gc/shenandoah/shenandoahMemoryPool.hpp" 51 #include "gc/shenandoah/shenandoahMetrics.hpp" 52 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp" 53 #include "gc/shenandoah/shenandoahNormalMode.hpp" 54 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 55 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 56 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp" 57 #include "gc/shenandoah/shenandoahPassiveMode.hpp" 58 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 59 #include "gc/shenandoah/shenandoahStringDedup.hpp" 60 #include "gc/shenandoah/shenandoahTaskqueue.hpp" 61 #include "gc/shenandoah/shenandoahTraversalMode.hpp" 62 #include "gc/shenandoah/shenandoahUtils.hpp" 63 #include "gc/shenandoah/shenandoahVerifier.hpp" 64 #include "gc/shenandoah/shenandoahCodeRoots.hpp" 65 #include "gc/shenandoah/shenandoahVMOperations.hpp" 66 #include "gc/shenandoah/shenandoahWorkGroup.hpp" 67 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp" 68 #if INCLUDE_JFR 69 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 70 #endif 71 72 #include "memory/metaspace.hpp" 73 #include "oops/compressedOops.inline.hpp" 74 #include "runtime/atomic.hpp" 75 #include "runtime/globals.hpp" 76 #include "runtime/interfaceSupport.inline.hpp" 77 #include "runtime/orderAccess.hpp" 78 #include "runtime/safepointMechanism.hpp" 79 #include "runtime/vmThread.hpp" 80 #include "services/mallocTracker.hpp" 81 82 #ifdef ASSERT 83 template <class T> 84 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) { 85 T o = RawAccess<>::oop_load(p); 86 if (! CompressedOops::is_null(o)) { 87 oop obj = CompressedOops::decode_not_null(o); 88 shenandoah_assert_not_forwarded(p, obj); 89 } 90 } 91 92 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); } 93 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); } 94 #endif 95 96 class ShenandoahPretouchHeapTask : public AbstractGangTask { 97 private: 98 ShenandoahRegionIterator _regions; 99 const size_t _page_size; 100 public: 101 ShenandoahPretouchHeapTask(size_t page_size) : 102 AbstractGangTask("Shenandoah Pretouch Heap"), 103 _page_size(page_size) {} 104 105 virtual void work(uint worker_id) { 106 ShenandoahHeapRegion* r = _regions.next(); 107 while (r != NULL) { 108 os::pretouch_memory(r->bottom(), r->end(), _page_size); 109 r = _regions.next(); 110 } 111 } 112 }; 113 114 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 115 private: 116 ShenandoahRegionIterator _regions; 117 char* _bitmap_base; 118 const size_t _bitmap_size; 119 const size_t _page_size; 120 public: 121 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 122 AbstractGangTask("Shenandoah Pretouch Bitmap"), 123 _bitmap_base(bitmap_base), 124 _bitmap_size(bitmap_size), 125 _page_size(page_size) {} 126 127 virtual void work(uint worker_id) { 128 ShenandoahHeapRegion* r = _regions.next(); 129 while (r != NULL) { 130 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 131 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 132 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 133 134 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 135 136 r = _regions.next(); 137 } 138 } 139 }; 140 141 jint ShenandoahHeap::initialize() { 142 initialize_heuristics(); 143 144 // 145 // Figure out heap sizing 146 // 147 148 size_t init_byte_size = InitialHeapSize; 149 size_t min_byte_size = MinHeapSize; 150 size_t max_byte_size = MaxHeapSize; 151 size_t heap_alignment = HeapAlignment; 152 153 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 154 155 if (ShenandoahAlwaysPreTouch) { 156 // Enabled pre-touch means the entire heap is committed right away. 157 init_byte_size = max_byte_size; 158 } 159 160 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 161 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 162 163 _num_regions = ShenandoahHeapRegion::region_count(); 164 165 size_t num_committed_regions = init_byte_size / reg_size_bytes; 166 num_committed_regions = MIN2(num_committed_regions, _num_regions); 167 assert(num_committed_regions <= _num_regions, "sanity"); 168 _initial_size = num_committed_regions * reg_size_bytes; 169 170 size_t num_min_regions = min_byte_size / reg_size_bytes; 171 num_min_regions = MIN2(num_min_regions, _num_regions); 172 assert(num_min_regions <= _num_regions, "sanity"); 173 _minimum_size = num_min_regions * reg_size_bytes; 174 175 _committed = _initial_size; 176 177 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 178 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 179 180 // 181 // Reserve and commit memory for heap 182 // 183 184 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 185 initialize_reserved_region(heap_rs); 186 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 187 _heap_region_special = heap_rs.special(); 188 189 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 190 "Misaligned heap: " PTR_FORMAT, p2i(base())); 191 192 #if SHENANDOAH_OPTIMIZED_OBJTASK 193 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 194 // Fail if we ever attempt to address more than we can. 195 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) { 196 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 197 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 198 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 199 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable()); 200 vm_exit_during_initialization("Fatal Error", buf); 201 } 202 #endif 203 204 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 205 if (!_heap_region_special) { 206 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 207 "Cannot commit heap memory"); 208 } 209 210 // 211 // Reserve and commit memory for bitmap(s) 212 // 213 214 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 215 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 216 217 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 218 219 guarantee(bitmap_bytes_per_region != 0, 220 "Bitmap bytes per region should not be zero"); 221 guarantee(is_power_of_2(bitmap_bytes_per_region), 222 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 223 224 if (bitmap_page_size > bitmap_bytes_per_region) { 225 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 226 _bitmap_bytes_per_slice = bitmap_page_size; 227 } else { 228 _bitmap_regions_per_slice = 1; 229 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 230 } 231 232 guarantee(_bitmap_regions_per_slice >= 1, 233 "Should have at least one region per slice: " SIZE_FORMAT, 234 _bitmap_regions_per_slice); 235 236 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 237 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 238 _bitmap_bytes_per_slice, bitmap_page_size); 239 240 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 241 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 242 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 243 _bitmap_region_special = bitmap.special(); 244 245 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 246 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 247 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 248 if (!_bitmap_region_special) { 249 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 250 "Cannot commit bitmap memory"); 251 } 252 253 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 254 255 if (ShenandoahVerify) { 256 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 257 if (!verify_bitmap.special()) { 258 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 259 "Cannot commit verification bitmap memory"); 260 } 261 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 262 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 263 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 264 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 265 } 266 267 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 268 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 269 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 270 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 271 _aux_bitmap_region_special = aux_bitmap.special(); 272 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 273 274 // 275 // Create regions and region sets 276 // 277 278 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 279 _free_set = new ShenandoahFreeSet(this, _num_regions); 280 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 281 282 { 283 ShenandoahHeapLocker locker(lock()); 284 285 size_t size_words = ShenandoahHeapRegion::region_size_words(); 286 287 for (size_t i = 0; i < _num_regions; i++) { 288 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; 289 bool is_committed = i < num_committed_regions; 290 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); 291 292 _marking_context->initialize_top_at_mark_start(r); 293 _regions[i] = r; 294 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 295 } 296 297 // Initialize to complete 298 _marking_context->mark_complete(); 299 300 _free_set->rebuild(); 301 } 302 303 if (ShenandoahAlwaysPreTouch) { 304 assert(!AlwaysPreTouch, "Should have been overridden"); 305 306 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 307 // before initialize() below zeroes it with initializing thread. For any given region, 308 // we touch the region and the corresponding bitmaps from the same thread. 309 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 310 311 size_t pretouch_heap_page_size = heap_page_size; 312 size_t pretouch_bitmap_page_size = bitmap_page_size; 313 314 #ifdef LINUX 315 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 316 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 317 // them into huge one. Therefore, we need to pretouch with smaller pages. 318 if (UseTransparentHugePages) { 319 pretouch_heap_page_size = (size_t)os::vm_page_size(); 320 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 321 } 322 #endif 323 324 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 325 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 326 327 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 328 _num_regions, pretouch_bitmap_page_size); 329 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 330 _workers->run_task(&bcl); 331 332 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 333 _num_regions, pretouch_heap_page_size); 334 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 335 _workers->run_task(&hcl); 336 } 337 338 // 339 // Initialize the rest of GC subsystems 340 // 341 342 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 343 for (uint worker = 0; worker < _max_workers; worker++) { 344 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 345 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 346 } 347 348 // There should probably be Shenandoah-specific options for these, 349 // just as there are G1-specific options. 350 { 351 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set(); 352 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold 353 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent 354 } 355 356 _monitoring_support = new ShenandoahMonitoringSupport(this); 357 _phase_timings = new ShenandoahPhaseTimings(); 358 ShenandoahStringDedup::initialize(); 359 ShenandoahCodeRoots::initialize(); 360 361 if (ShenandoahAllocationTrace) { 362 _alloc_tracker = new ShenandoahAllocTracker(); 363 } 364 365 if (ShenandoahPacing) { 366 _pacer = new ShenandoahPacer(this); 367 _pacer->setup_for_idle(); 368 } else { 369 _pacer = NULL; 370 } 371 372 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ? 373 new ShenandoahTraversalGC(this, _num_regions) : 374 NULL; 375 376 _control_thread = new ShenandoahControlThread(); 377 378 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 379 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 380 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 381 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 382 ); 383 384 log_info(gc, init)("Safepointing mechanism: %s", 385 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" : 386 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown")); 387 388 return JNI_OK; 389 } 390 391 void ShenandoahHeap::initialize_heuristics() { 392 if (ShenandoahGCMode != NULL) { 393 if (strcmp(ShenandoahGCMode, "traversal") == 0) { 394 _gc_mode = new ShenandoahTraversalMode(); 395 } else if (strcmp(ShenandoahGCMode, "normal") == 0) { 396 _gc_mode = new ShenandoahNormalMode(); 397 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 398 _gc_mode = new ShenandoahPassiveMode(); 399 } else { 400 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 401 } 402 } else { 403 ShouldNotReachHere(); 404 } 405 _gc_mode->initialize_flags(); 406 _heuristics = _gc_mode->initialize_heuristics(); 407 408 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 409 vm_exit_during_initialization( 410 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 411 _heuristics->name())); 412 } 413 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 414 vm_exit_during_initialization( 415 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 416 _heuristics->name())); 417 } 418 log_info(gc, init)("Shenandoah heuristics: %s", 419 _heuristics->name()); 420 } 421 422 #ifdef _MSC_VER 423 #pragma warning( push ) 424 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 425 #endif 426 427 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 428 CollectedHeap(), 429 _initial_size(0), 430 _used(0), 431 _committed(0), 432 _bytes_allocated_since_gc_start(0), 433 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), 434 _workers(NULL), 435 _safepoint_workers(NULL), 436 _heap_region_special(false), 437 _num_regions(0), 438 _regions(NULL), 439 _update_refs_iterator(this), 440 _control_thread(NULL), 441 _shenandoah_policy(policy), 442 _heuristics(NULL), 443 _free_set(NULL), 444 _scm(new ShenandoahConcurrentMark()), 445 _traversal_gc(NULL), 446 _full_gc(new ShenandoahMarkCompact()), 447 _pacer(NULL), 448 _verifier(NULL), 449 _alloc_tracker(NULL), 450 _phase_timings(NULL), 451 _monitoring_support(NULL), 452 _memory_pool(NULL), 453 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), 454 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), 455 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 456 _soft_ref_policy(), 457 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes), 458 _ref_processor(NULL), 459 _marking_context(NULL), 460 _bitmap_size(0), 461 _bitmap_regions_per_slice(0), 462 _bitmap_bytes_per_slice(0), 463 _bitmap_region_special(false), 464 _aux_bitmap_region_special(false), 465 _liveness_cache(NULL), 466 _collection_set(NULL) 467 { 468 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); 469 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); 470 471 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); 472 473 _max_workers = MAX2(_max_workers, 1U); 474 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, 475 /* are_GC_task_threads */ true, 476 /* are_ConcurrentGC_threads */ true); 477 if (_workers == NULL) { 478 vm_exit_during_initialization("Failed necessary allocation."); 479 } else { 480 _workers->initialize_workers(); 481 } 482 483 if (ShenandoahParallelSafepointThreads > 1) { 484 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread", 485 ShenandoahParallelSafepointThreads, 486 /* are_GC_task_threads */ false, 487 /* are_ConcurrentGC_threads */ false); 488 _safepoint_workers->initialize_workers(); 489 } 490 } 491 492 #ifdef _MSC_VER 493 #pragma warning( pop ) 494 #endif 495 496 class ShenandoahResetBitmapTask : public AbstractGangTask { 497 private: 498 ShenandoahRegionIterator _regions; 499 500 public: 501 ShenandoahResetBitmapTask() : 502 AbstractGangTask("Parallel Reset Bitmap Task") {} 503 504 void work(uint worker_id) { 505 ShenandoahHeapRegion* region = _regions.next(); 506 ShenandoahHeap* heap = ShenandoahHeap::heap(); 507 ShenandoahMarkingContext* const ctx = heap->marking_context(); 508 while (region != NULL) { 509 if (heap->is_bitmap_slice_committed(region)) { 510 ctx->clear_bitmap(region); 511 } 512 region = _regions.next(); 513 } 514 } 515 }; 516 517 void ShenandoahHeap::reset_mark_bitmap() { 518 assert_gc_workers(_workers->active_workers()); 519 mark_incomplete_marking_context(); 520 521 ShenandoahResetBitmapTask task; 522 _workers->run_task(&task); 523 } 524 525 void ShenandoahHeap::print_on(outputStream* st) const { 526 st->print_cr("Shenandoah Heap"); 527 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 528 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 529 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 530 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 531 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 532 num_regions(), 533 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 534 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 535 536 st->print("Status: "); 537 if (has_forwarded_objects()) st->print("has forwarded objects, "); 538 if (is_concurrent_mark_in_progress()) st->print("marking, "); 539 if (is_evacuation_in_progress()) st->print("evacuating, "); 540 if (is_update_refs_in_progress()) st->print("updating refs, "); 541 if (is_concurrent_traversal_in_progress()) st->print("traversal, "); 542 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 543 if (is_full_gc_in_progress()) st->print("full gc, "); 544 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 545 if (is_concurrent_root_in_progress()) st->print("concurrent roots, "); 546 547 if (cancelled_gc()) { 548 st->print("cancelled"); 549 } else { 550 st->print("not cancelled"); 551 } 552 st->cr(); 553 554 st->print_cr("Reserved region:"); 555 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 556 p2i(reserved_region().start()), 557 p2i(reserved_region().end())); 558 559 ShenandoahCollectionSet* cset = collection_set(); 560 st->print_cr("Collection set:"); 561 if (cset != NULL) { 562 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 563 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 564 } else { 565 st->print_cr(" (NULL)"); 566 } 567 568 st->cr(); 569 MetaspaceUtils::print_on(st); 570 571 if (Verbose) { 572 print_heap_regions_on(st); 573 } 574 } 575 576 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 577 public: 578 void do_thread(Thread* thread) { 579 assert(thread != NULL, "Sanity"); 580 assert(thread->is_Worker_thread(), "Only worker thread expected"); 581 ShenandoahThreadLocalData::initialize_gclab(thread); 582 } 583 }; 584 585 void ShenandoahHeap::post_initialize() { 586 CollectedHeap::post_initialize(); 587 MutexLocker ml(Threads_lock); 588 589 ShenandoahInitWorkerGCLABClosure init_gclabs; 590 _workers->threads_do(&init_gclabs); 591 592 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 593 // Now, we will let WorkGang to initialize gclab when new worker is created. 594 _workers->set_initialize_gclab(); 595 596 _scm->initialize(_max_workers); 597 _full_gc->initialize(_gc_timer); 598 599 ref_processing_init(); 600 601 _heuristics->initialize(); 602 603 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 604 } 605 606 size_t ShenandoahHeap::used() const { 607 return Atomic::load_acquire(&_used); 608 } 609 610 size_t ShenandoahHeap::committed() const { 611 OrderAccess::acquire(); 612 return _committed; 613 } 614 615 void ShenandoahHeap::increase_committed(size_t bytes) { 616 assert_heaplock_or_safepoint(); 617 _committed += bytes; 618 } 619 620 void ShenandoahHeap::decrease_committed(size_t bytes) { 621 assert_heaplock_or_safepoint(); 622 _committed -= bytes; 623 } 624 625 void ShenandoahHeap::increase_used(size_t bytes) { 626 Atomic::add(&_used, bytes); 627 } 628 629 void ShenandoahHeap::set_used(size_t bytes) { 630 Atomic::release_store_fence(&_used, bytes); 631 } 632 633 void ShenandoahHeap::decrease_used(size_t bytes) { 634 assert(used() >= bytes, "never decrease heap size by more than we've left"); 635 Atomic::sub(&_used, bytes); 636 } 637 638 void ShenandoahHeap::increase_allocated(size_t bytes) { 639 Atomic::add(&_bytes_allocated_since_gc_start, bytes); 640 } 641 642 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 643 size_t bytes = words * HeapWordSize; 644 if (!waste) { 645 increase_used(bytes); 646 } 647 increase_allocated(bytes); 648 if (ShenandoahPacing) { 649 control_thread()->pacing_notify_alloc(words); 650 if (waste) { 651 pacer()->claim_for_alloc(words, true); 652 } 653 } 654 } 655 656 size_t ShenandoahHeap::capacity() const { 657 return committed(); 658 } 659 660 size_t ShenandoahHeap::max_capacity() const { 661 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 662 } 663 664 size_t ShenandoahHeap::min_capacity() const { 665 return _minimum_size; 666 } 667 668 size_t ShenandoahHeap::initial_capacity() const { 669 return _initial_size; 670 } 671 672 bool ShenandoahHeap::is_in(const void* p) const { 673 HeapWord* heap_base = (HeapWord*) base(); 674 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 675 return p >= heap_base && p < last_region_end; 676 } 677 678 void ShenandoahHeap::op_uncommit(double shrink_before) { 679 assert (ShenandoahUncommit, "should be enabled"); 680 681 // Application allocates from the beginning of the heap, and GC allocates at 682 // the end of it. It is more efficient to uncommit from the end, so that applications 683 // could enjoy the near committed regions. GC allocations are much less frequent, 684 // and therefore can accept the committing costs. 685 686 size_t count = 0; 687 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 688 ShenandoahHeapRegion* r = get_region(i - 1); 689 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 690 ShenandoahHeapLocker locker(lock()); 691 if (r->is_empty_committed()) { 692 // Do not uncommit below minimal capacity 693 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 694 break; 695 } 696 697 r->make_uncommitted(); 698 count++; 699 } 700 } 701 SpinPause(); // allow allocators to take the lock 702 } 703 704 if (count > 0) { 705 control_thread()->notify_heap_changed(); 706 } 707 } 708 709 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 710 // New object should fit the GCLAB size 711 size_t min_size = MAX2(size, PLAB::min_size()); 712 713 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 714 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 715 new_size = MIN2(new_size, PLAB::max_size()); 716 new_size = MAX2(new_size, PLAB::min_size()); 717 718 // Record new heuristic value even if we take any shortcut. This captures 719 // the case when moderately-sized objects always take a shortcut. At some point, 720 // heuristics should catch up with them. 721 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 722 723 if (new_size < size) { 724 // New size still does not fit the object. Fall back to shared allocation. 725 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 726 return NULL; 727 } 728 729 // Retire current GCLAB, and allocate a new one. 730 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 731 gclab->retire(); 732 733 size_t actual_size = 0; 734 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 735 if (gclab_buf == NULL) { 736 return NULL; 737 } 738 739 assert (size <= actual_size, "allocation should fit"); 740 741 if (ZeroTLAB) { 742 // ..and clear it. 743 Copy::zero_to_words(gclab_buf, actual_size); 744 } else { 745 // ...and zap just allocated object. 746 #ifdef ASSERT 747 // Skip mangling the space corresponding to the object header to 748 // ensure that the returned space is not considered parsable by 749 // any concurrent GC thread. 750 size_t hdr_size = oopDesc::header_size(); 751 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 752 #endif // ASSERT 753 } 754 gclab->set_buf(gclab_buf, actual_size); 755 return gclab->allocate(size); 756 } 757 758 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 759 size_t requested_size, 760 size_t* actual_size) { 761 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 762 HeapWord* res = allocate_memory(req); 763 if (res != NULL) { 764 *actual_size = req.actual_size(); 765 } else { 766 *actual_size = 0; 767 } 768 return res; 769 } 770 771 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 772 size_t word_size, 773 size_t* actual_size) { 774 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 775 HeapWord* res = allocate_memory(req); 776 if (res != NULL) { 777 *actual_size = req.actual_size(); 778 } else { 779 *actual_size = 0; 780 } 781 return res; 782 } 783 784 ShenandoahHeap* ShenandoahHeap::heap() { 785 CollectedHeap* heap = Universe::heap(); 786 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); 787 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap"); 788 return (ShenandoahHeap*) heap; 789 } 790 791 ShenandoahHeap* ShenandoahHeap::heap_no_check() { 792 CollectedHeap* heap = Universe::heap(); 793 return (ShenandoahHeap*) heap; 794 } 795 796 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 797 ShenandoahAllocTrace trace_alloc(req.size(), req.type()); 798 799 intptr_t pacer_epoch = 0; 800 bool in_new_region = false; 801 HeapWord* result = NULL; 802 803 if (req.is_mutator_alloc()) { 804 if (ShenandoahPacing) { 805 pacer()->pace_for_alloc(req.size()); 806 pacer_epoch = pacer()->epoch(); 807 } 808 809 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 810 result = allocate_memory_under_lock(req, in_new_region); 811 } 812 813 // Allocation failed, block until control thread reacted, then retry allocation. 814 // 815 // It might happen that one of the threads requesting allocation would unblock 816 // way later after GC happened, only to fail the second allocation, because 817 // other threads have already depleted the free storage. In this case, a better 818 // strategy is to try again, as long as GC makes progress. 819 // 820 // Then, we need to make sure the allocation was retried after at least one 821 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 822 823 size_t tries = 0; 824 825 while (result == NULL && _progress_last_gc.is_set()) { 826 tries++; 827 control_thread()->handle_alloc_failure(req.size()); 828 result = allocate_memory_under_lock(req, in_new_region); 829 } 830 831 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 832 tries++; 833 control_thread()->handle_alloc_failure(req.size()); 834 result = allocate_memory_under_lock(req, in_new_region); 835 } 836 837 } else { 838 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 839 result = allocate_memory_under_lock(req, in_new_region); 840 // Do not call handle_alloc_failure() here, because we cannot block. 841 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 842 } 843 844 if (in_new_region) { 845 control_thread()->notify_heap_changed(); 846 } 847 848 if (result != NULL) { 849 size_t requested = req.size(); 850 size_t actual = req.actual_size(); 851 852 assert (req.is_lab_alloc() || (requested == actual), 853 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 854 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 855 856 if (req.is_mutator_alloc()) { 857 notify_mutator_alloc_words(actual, false); 858 859 // If we requested more than we were granted, give the rest back to pacer. 860 // This only matters if we are in the same pacing epoch: do not try to unpace 861 // over the budget for the other phase. 862 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 863 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 864 } 865 } else { 866 increase_used(actual*HeapWordSize); 867 } 868 } 869 870 return result; 871 } 872 873 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 874 ShenandoahHeapLocker locker(lock()); 875 return _free_set->allocate(req, in_new_region); 876 } 877 878 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 879 bool* gc_overhead_limit_was_exceeded) { 880 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 881 return allocate_memory(req); 882 } 883 884 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 885 size_t size, 886 Metaspace::MetadataType mdtype) { 887 MetaWord* result; 888 889 // Inform metaspace OOM to GC heuristics if class unloading is possible. 890 if (heuristics()->can_unload_classes()) { 891 ShenandoahHeuristics* h = heuristics(); 892 h->record_metaspace_oom(); 893 } 894 895 // Expand and retry allocation 896 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 897 if (result != NULL) { 898 return result; 899 } 900 901 // Start full GC 902 collect(GCCause::_metadata_GC_clear_soft_refs); 903 904 // Retry allocation 905 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 906 if (result != NULL) { 907 return result; 908 } 909 910 // Expand and retry allocation 911 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 912 if (result != NULL) { 913 return result; 914 } 915 916 // Out of memory 917 return NULL; 918 } 919 920 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 921 private: 922 ShenandoahHeap* const _heap; 923 Thread* const _thread; 924 public: 925 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 926 _heap(heap), _thread(Thread::current()) {} 927 928 void do_object(oop p) { 929 shenandoah_assert_marked(NULL, p); 930 if (!p->is_forwarded()) { 931 _heap->evacuate_object(p, _thread); 932 } 933 } 934 }; 935 936 class ShenandoahEvacuationTask : public AbstractGangTask { 937 private: 938 ShenandoahHeap* const _sh; 939 ShenandoahCollectionSet* const _cs; 940 bool _concurrent; 941 public: 942 ShenandoahEvacuationTask(ShenandoahHeap* sh, 943 ShenandoahCollectionSet* cs, 944 bool concurrent) : 945 AbstractGangTask("Parallel Evacuation Task"), 946 _sh(sh), 947 _cs(cs), 948 _concurrent(concurrent) 949 {} 950 951 void work(uint worker_id) { 952 if (_concurrent) { 953 ShenandoahConcurrentWorkerSession worker_session(worker_id); 954 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 955 ShenandoahEvacOOMScope oom_evac_scope; 956 do_work(); 957 } else { 958 ShenandoahParallelWorkerSession worker_session(worker_id); 959 ShenandoahEvacOOMScope oom_evac_scope; 960 do_work(); 961 } 962 } 963 964 private: 965 void do_work() { 966 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 967 ShenandoahHeapRegion* r; 968 while ((r =_cs->claim_next()) != NULL) { 969 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->region_number()); 970 _sh->marked_object_iterate(r, &cl); 971 972 if (ShenandoahPacing) { 973 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 974 } 975 976 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 977 break; 978 } 979 } 980 } 981 }; 982 983 void ShenandoahHeap::trash_cset_regions() { 984 ShenandoahHeapLocker locker(lock()); 985 986 ShenandoahCollectionSet* set = collection_set(); 987 ShenandoahHeapRegion* r; 988 set->clear_current_index(); 989 while ((r = set->next()) != NULL) { 990 r->make_trash(); 991 } 992 collection_set()->clear(); 993 } 994 995 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 996 st->print_cr("Heap Regions:"); 997 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 998 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 999 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); 1000 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)"); 1001 1002 for (size_t i = 0; i < num_regions(); i++) { 1003 get_region(i)->print_on(st); 1004 } 1005 } 1006 1007 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 1008 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1009 1010 oop humongous_obj = oop(start->bottom()); 1011 size_t size = humongous_obj->size(); 1012 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1013 size_t index = start->region_number() + required_regions - 1; 1014 1015 assert(!start->has_live(), "liveness must be zero"); 1016 1017 for(size_t i = 0; i < required_regions; i++) { 1018 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1019 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1020 ShenandoahHeapRegion* region = get_region(index --); 1021 1022 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1023 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1024 1025 region->make_trash_immediate(); 1026 } 1027 } 1028 1029 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1030 public: 1031 void do_thread(Thread* thread) { 1032 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1033 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1034 gclab->retire(); 1035 } 1036 }; 1037 1038 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 1039 if (UseTLAB) { 1040 CollectedHeap::ensure_parsability(retire_tlabs); 1041 } 1042 ShenandoahRetireGCLABClosure cl; 1043 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1044 cl.do_thread(t); 1045 } 1046 workers()->threads_do(&cl); 1047 } 1048 1049 void ShenandoahHeap::resize_tlabs() { 1050 CollectedHeap::resize_all_tlabs(); 1051 } 1052 1053 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 1054 private: 1055 ShenandoahRootEvacuator* _rp; 1056 1057 public: 1058 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 1059 AbstractGangTask("Shenandoah evacuate and update roots"), 1060 _rp(rp) {} 1061 1062 void work(uint worker_id) { 1063 ShenandoahParallelWorkerSession worker_session(worker_id); 1064 ShenandoahEvacOOMScope oom_evac_scope; 1065 ShenandoahEvacuateUpdateRootsClosure cl; 1066 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 1067 _rp->roots_do(worker_id, &cl); 1068 } 1069 }; 1070 1071 void ShenandoahHeap::evacuate_and_update_roots() { 1072 #if COMPILER2_OR_JVMCI 1073 DerivedPointerTable::clear(); 1074 #endif 1075 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1076 { 1077 // Include concurrent roots if current cycle can not process those roots concurrently 1078 ShenandoahRootEvacuator rp(workers()->active_workers(), 1079 ShenandoahPhaseTimings::init_evac, 1080 !ShenandoahConcurrentRoots::should_do_concurrent_roots(), 1081 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 1082 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 1083 workers()->run_task(&roots_task); 1084 } 1085 1086 #if COMPILER2_OR_JVMCI 1087 DerivedPointerTable::update_pointers(); 1088 #endif 1089 } 1090 1091 // Returns size in bytes 1092 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1093 if (ShenandoahElasticTLAB) { 1094 // With Elastic TLABs, return the max allowed size, and let the allocation path 1095 // figure out the safe size for current allocation. 1096 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1097 } else { 1098 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1099 } 1100 } 1101 1102 size_t ShenandoahHeap::max_tlab_size() const { 1103 // Returns size in words 1104 return ShenandoahHeapRegion::max_tlab_size_words(); 1105 } 1106 1107 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure { 1108 public: 1109 void do_thread(Thread* thread) { 1110 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1111 gclab->retire(); 1112 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1113 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1114 } 1115 } 1116 }; 1117 1118 void ShenandoahHeap::retire_and_reset_gclabs() { 1119 ShenandoahRetireAndResetGCLABClosure cl; 1120 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1121 cl.do_thread(t); 1122 } 1123 workers()->threads_do(&cl); 1124 } 1125 1126 void ShenandoahHeap::collect(GCCause::Cause cause) { 1127 control_thread()->request_gc(cause); 1128 } 1129 1130 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1131 //assert(false, "Shouldn't need to do full collections"); 1132 } 1133 1134 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1135 Space* sp = heap_region_containing(addr); 1136 if (sp != NULL) { 1137 return sp->block_start(addr); 1138 } 1139 return NULL; 1140 } 1141 1142 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1143 Space* sp = heap_region_containing(addr); 1144 return sp->block_is_obj(addr); 1145 } 1146 1147 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const { 1148 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr); 1149 } 1150 1151 jlong ShenandoahHeap::millis_since_last_gc() { 1152 double v = heuristics()->time_since_last_gc() * 1000; 1153 assert(0 <= v && v <= max_jlong, "value should fit: %f", v); 1154 return (jlong)v; 1155 } 1156 1157 void ShenandoahHeap::prepare_for_verify() { 1158 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) { 1159 make_parsable(false); 1160 } 1161 } 1162 1163 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1164 workers()->print_worker_threads_on(st); 1165 if (ShenandoahStringDedup::is_enabled()) { 1166 ShenandoahStringDedup::print_worker_threads_on(st); 1167 } 1168 } 1169 1170 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1171 workers()->threads_do(tcl); 1172 if (_safepoint_workers != NULL) { 1173 _safepoint_workers->threads_do(tcl); 1174 } 1175 if (ShenandoahStringDedup::is_enabled()) { 1176 ShenandoahStringDedup::threads_do(tcl); 1177 } 1178 } 1179 1180 void ShenandoahHeap::print_tracing_info() const { 1181 LogTarget(Info, gc, stats) lt; 1182 if (lt.is_enabled()) { 1183 ResourceMark rm; 1184 LogStream ls(lt); 1185 1186 phase_timings()->print_on(&ls); 1187 1188 ls.cr(); 1189 ls.cr(); 1190 1191 shenandoah_policy()->print_gc_stats(&ls); 1192 1193 ls.cr(); 1194 ls.cr(); 1195 1196 if (ShenandoahPacing) { 1197 pacer()->print_on(&ls); 1198 } 1199 1200 ls.cr(); 1201 ls.cr(); 1202 1203 if (ShenandoahAllocationTrace) { 1204 assert(alloc_tracker() != NULL, "Must be"); 1205 alloc_tracker()->print_on(&ls); 1206 } else { 1207 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); 1208 } 1209 } 1210 } 1211 1212 void ShenandoahHeap::verify(VerifyOption vo) { 1213 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1214 if (ShenandoahVerify) { 1215 verifier()->verify_generic(vo); 1216 } else { 1217 // TODO: Consider allocating verification bitmaps on demand, 1218 // and turn this on unconditionally. 1219 } 1220 } 1221 } 1222 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1223 return _free_set->capacity(); 1224 } 1225 1226 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1227 private: 1228 MarkBitMap* _bitmap; 1229 Stack<oop,mtGC>* _oop_stack; 1230 1231 template <class T> 1232 void do_oop_work(T* p) { 1233 T o = RawAccess<>::oop_load(p); 1234 if (!CompressedOops::is_null(o)) { 1235 oop obj = CompressedOops::decode_not_null(o); 1236 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 1237 if (fwd == NULL) { 1238 // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp. 1239 // 1240 // That operation walks the reachable objects on its own, storing the marking 1241 // wavefront in the object marks. When it is done, it calls the CollectedHeap 1242 // to iterate over all objects to clean up the mess. When it reaches here, 1243 // the Shenandoah fwdptr resolution code encounters the marked objects with 1244 // NULL forwardee. Trying to act on that would crash the VM. Or fail the 1245 // asserts, should we go for resolve_forwarded_pointer(obj). 1246 // 1247 // Therefore, we have to dodge it by doing the raw access to forwardee, and 1248 // assuming the object had no forwardee, if that thing is NULL. 1249 } else { 1250 obj = fwd; 1251 } 1252 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1253 if (!_bitmap->is_marked((HeapWord*) obj)) { 1254 _bitmap->mark((HeapWord*) obj); 1255 _oop_stack->push(obj); 1256 } 1257 } 1258 } 1259 public: 1260 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1261 _bitmap(bitmap), _oop_stack(oop_stack) {} 1262 void do_oop(oop* p) { do_oop_work(p); } 1263 void do_oop(narrowOop* p) { do_oop_work(p); } 1264 }; 1265 1266 /* 1267 * This is public API, used in preparation of object_iterate(). 1268 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1269 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1270 * control, we call SH::make_tlabs_parsable(). 1271 */ 1272 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1273 // No-op. 1274 } 1275 1276 /* 1277 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1278 * 1279 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1280 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1281 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1282 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1283 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1284 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1285 * wiped the bitmap in preparation for next marking). 1286 * 1287 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1288 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1289 * is allowed to report dead objects, but is not required to do so. 1290 */ 1291 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1292 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1293 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1294 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1295 return; 1296 } 1297 1298 // Reset bitmap 1299 _aux_bit_map.clear(); 1300 1301 Stack<oop,mtGC> oop_stack; 1302 1303 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects. 1304 ShenandoahHeapIterationRootScanner rp; 1305 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1306 1307 // If we are unloading classes right now, we should not touch weak roots, 1308 // on the off-chance we would evacuate them and make them live accidentally. 1309 // In other cases, we have to scan all roots. 1310 if (is_evacuation_in_progress() && unload_classes()) { 1311 rp.strong_roots_do(&oops); 1312 } else { 1313 rp.roots_do(&oops); 1314 } 1315 1316 // Work through the oop stack to traverse heap. 1317 while (! oop_stack.is_empty()) { 1318 oop obj = oop_stack.pop(); 1319 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1320 cl->do_object(obj); 1321 obj->oop_iterate(&oops); 1322 } 1323 1324 assert(oop_stack.is_empty(), "should be empty"); 1325 1326 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1327 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1328 } 1329 } 1330 1331 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 1332 void ShenandoahHeap::keep_alive(oop obj) { 1333 if (is_concurrent_mark_in_progress()) { 1334 ShenandoahBarrierSet::barrier_set()->enqueue(obj); 1335 } else { 1336 // Otherwise, it must be live, guaranteed by LRB 1337 shenandoah_assert_marked_if(NULL, obj, has_forwarded_objects()); 1338 } 1339 } 1340 1341 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1342 for (size_t i = 0; i < num_regions(); i++) { 1343 ShenandoahHeapRegion* current = get_region(i); 1344 blk->heap_region_do(current); 1345 } 1346 } 1347 1348 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1349 private: 1350 ShenandoahHeap* const _heap; 1351 ShenandoahHeapRegionClosure* const _blk; 1352 1353 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t)); 1354 volatile size_t _index; 1355 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0); 1356 1357 public: 1358 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1359 AbstractGangTask("Parallel Region Task"), 1360 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1361 1362 void work(uint worker_id) { 1363 size_t stride = ShenandoahParallelRegionStride; 1364 1365 size_t max = _heap->num_regions(); 1366 while (_index < max) { 1367 size_t cur = Atomic::add(&_index, stride) - stride; 1368 size_t start = cur; 1369 size_t end = MIN2(cur + stride, max); 1370 if (start >= max) break; 1371 1372 for (size_t i = cur; i < end; i++) { 1373 ShenandoahHeapRegion* current = _heap->get_region(i); 1374 _blk->heap_region_do(current); 1375 } 1376 } 1377 } 1378 }; 1379 1380 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1381 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1382 if (num_regions() > ShenandoahParallelRegionStride) { 1383 ShenandoahParallelHeapRegionTask task(blk); 1384 workers()->run_task(&task); 1385 } else { 1386 heap_region_iterate(blk); 1387 } 1388 } 1389 1390 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { 1391 private: 1392 ShenandoahMarkingContext* const _ctx; 1393 public: 1394 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1395 1396 void heap_region_do(ShenandoahHeapRegion* r) { 1397 if (r->is_active()) { 1398 r->clear_live_data(); 1399 _ctx->capture_top_at_mark_start(r); 1400 } else { 1401 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1402 assert(_ctx->top_at_mark_start(r) == r->top(), 1403 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()); 1404 } 1405 } 1406 1407 bool is_thread_safe() { return true; } 1408 }; 1409 1410 void ShenandoahHeap::op_init_mark() { 1411 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1412 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1413 1414 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1415 assert(!marking_context()->is_complete(), "should not be complete"); 1416 1417 if (ShenandoahVerify) { 1418 verifier()->verify_before_concmark(); 1419 } 1420 1421 if (VerifyBeforeGC) { 1422 Universe::verify(); 1423 } 1424 1425 set_concurrent_mark_in_progress(true); 1426 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1427 { 1428 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1429 make_parsable(true); 1430 } 1431 1432 { 1433 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); 1434 ShenandoahClearLivenessClosure clc; 1435 parallel_heap_region_iterate(&clc); 1436 } 1437 1438 // Make above changes visible to worker threads 1439 OrderAccess::fence(); 1440 1441 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1442 1443 if (UseTLAB) { 1444 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1445 resize_tlabs(); 1446 } 1447 1448 if (ShenandoahPacing) { 1449 pacer()->setup_for_mark(); 1450 } 1451 } 1452 1453 void ShenandoahHeap::op_mark() { 1454 concurrent_mark()->mark_from_roots(); 1455 } 1456 1457 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { 1458 private: 1459 ShenandoahMarkingContext* const _ctx; 1460 public: 1461 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} 1462 1463 void heap_region_do(ShenandoahHeapRegion* r) { 1464 if (r->is_active()) { 1465 HeapWord *tams = _ctx->top_at_mark_start(r); 1466 HeapWord *top = r->top(); 1467 if (top > tams) { 1468 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1469 } 1470 } else { 1471 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1472 assert(_ctx->top_at_mark_start(r) == r->top(), 1473 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number()); 1474 } 1475 } 1476 1477 bool is_thread_safe() { return true; } 1478 }; 1479 1480 void ShenandoahHeap::op_final_mark() { 1481 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 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 (has_forwarded_objects()) { 1497 // Degen may be caused by failed evacuation of roots 1498 if (is_degenerated_gc_in_progress()) { 1499 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 1500 } else { 1501 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots); 1502 } 1503 set_has_forwarded_objects(false); 1504 } 1505 1506 if (ShenandoahVerify) { 1507 verifier()->verify_roots_no_forwarded(); 1508 } 1509 // All allocations past TAMS are implicitly live, adjust the region data. 1510 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1511 { 1512 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); 1513 ShenandoahCompleteLivenessClosure cl; 1514 parallel_heap_region_iterate(&cl); 1515 } 1516 1517 // Force the threads to reacquire their TLABs outside the collection set. 1518 { 1519 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs); 1520 make_parsable(true); 1521 } 1522 1523 // We are about to select the collection set, make sure it knows about 1524 // current pinning status. Also, this allows trashing more regions that 1525 // now have their pinning status dropped. 1526 { 1527 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned); 1528 sync_pinned_region_status(); 1529 } 1530 1531 // Trash the collection set left over from previous cycle, if any. 1532 { 1533 ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset); 1534 trash_cset_regions(); 1535 } 1536 1537 { 1538 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac); 1539 1540 ShenandoahHeapLocker locker(lock()); 1541 _collection_set->clear(); 1542 _free_set->clear(); 1543 1544 heuristics()->choose_collection_set(_collection_set); 1545 1546 _free_set->rebuild(); 1547 } 1548 1549 if (!is_degenerated_gc_in_progress()) { 1550 prepare_concurrent_roots(); 1551 prepare_concurrent_unloading(); 1552 } 1553 1554 // If collection set has candidates, start evacuation. 1555 // Otherwise, bypass the rest of the cycle. 1556 if (!collection_set()->is_empty()) { 1557 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1558 1559 if (ShenandoahVerify) { 1560 verifier()->verify_before_evacuation(); 1561 } 1562 1563 set_evacuation_in_progress(true); 1564 // From here on, we need to update references. 1565 set_has_forwarded_objects(true); 1566 1567 if (!is_degenerated_gc_in_progress()) { 1568 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1569 ShenandoahCodeRoots::arm_nmethods(); 1570 } 1571 evacuate_and_update_roots(); 1572 } 1573 1574 if (ShenandoahPacing) { 1575 pacer()->setup_for_evac(); 1576 } 1577 1578 if (ShenandoahVerify) { 1579 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None; 1580 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1581 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots); 1582 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots); 1583 } 1584 1585 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1586 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CodeRoots); 1587 } 1588 verifier()->verify_roots_no_forwarded_except(types); 1589 verifier()->verify_during_evacuation(); 1590 } 1591 } else { 1592 if (ShenandoahVerify) { 1593 verifier()->verify_after_concmark(); 1594 } 1595 1596 if (VerifyAfterGC) { 1597 Universe::verify(); 1598 } 1599 } 1600 1601 } else { 1602 // If this cycle was updating references, we need to keep the has_forwarded_objects 1603 // flag on, for subsequent phases to deal with it. 1604 concurrent_mark()->cancel(); 1605 set_concurrent_mark_in_progress(false); 1606 1607 if (process_references()) { 1608 // Abandon reference processing right away: pre-cleaning must have failed. 1609 ReferenceProcessor *rp = ref_processor(); 1610 rp->disable_discovery(); 1611 rp->abandon_partial_discovery(); 1612 rp->verify_no_references_recorded(); 1613 } 1614 } 1615 } 1616 1617 void ShenandoahHeap::op_final_evac() { 1618 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1619 1620 set_evacuation_in_progress(false); 1621 1622 { 1623 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_retire_gclabs); 1624 retire_and_reset_gclabs(); 1625 } 1626 1627 if (ShenandoahVerify) { 1628 verifier()->verify_after_evacuation(); 1629 } 1630 1631 if (VerifyAfterGC) { 1632 Universe::verify(); 1633 } 1634 } 1635 1636 void ShenandoahHeap::op_conc_evac() { 1637 ShenandoahEvacuationTask task(this, _collection_set, true); 1638 workers()->run_task(&task); 1639 } 1640 1641 void ShenandoahHeap::op_stw_evac() { 1642 ShenandoahEvacuationTask task(this, _collection_set, false); 1643 workers()->run_task(&task); 1644 } 1645 1646 void ShenandoahHeap::op_updaterefs() { 1647 update_heap_references(true); 1648 } 1649 1650 void ShenandoahHeap::op_cleanup() { 1651 free_set()->recycle_trash(); 1652 } 1653 1654 class ShenandoahConcurrentRootsEvacUpdateTask : public AbstractGangTask { 1655 private: 1656 ShenandoahVMRoots<true /*concurrent*/> _vm_roots; 1657 ShenandoahWeakRoots<true /*concurrent*/> _weak_roots; 1658 ShenandoahClassLoaderDataRoots<true /*concurrent*/, false /*single threaded*/> _cld_roots; 1659 1660 public: 1661 ShenandoahConcurrentRootsEvacUpdateTask() : 1662 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task") { 1663 } 1664 1665 void work(uint worker_id) { 1666 ShenandoahEvacOOMScope oom; 1667 { 1668 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration 1669 // may race against OopStorage::release() calls. 1670 ShenandoahEvacUpdateOopStorageRootsClosure cl; 1671 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1672 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1673 } 1674 1675 { 1676 ShenandoahEvacuateUpdateRootsClosure cl; 1677 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong); 1678 _cld_roots.cld_do(&clds); 1679 } 1680 } 1681 }; 1682 1683 void ShenandoahHeap::op_roots() { 1684 if (is_concurrent_root_in_progress()) { 1685 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1686 _unloader.unload(); 1687 } 1688 1689 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1690 ShenandoahConcurrentRootsEvacUpdateTask task; 1691 workers()->run_task(&task); 1692 } 1693 } 1694 1695 set_concurrent_root_in_progress(false); 1696 } 1697 1698 void ShenandoahHeap::op_reset() { 1699 reset_mark_bitmap(); 1700 } 1701 1702 void ShenandoahHeap::op_preclean() { 1703 concurrent_mark()->preclean_weak_refs(); 1704 } 1705 1706 void ShenandoahHeap::op_init_traversal() { 1707 traversal_gc()->init_traversal_collection(); 1708 } 1709 1710 void ShenandoahHeap::op_traversal() { 1711 traversal_gc()->concurrent_traversal_collection(); 1712 } 1713 1714 void ShenandoahHeap::op_final_traversal() { 1715 traversal_gc()->final_traversal_collection(); 1716 } 1717 1718 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1719 ShenandoahMetricsSnapshot metrics; 1720 metrics.snap_before(); 1721 1722 full_gc()->do_it(cause); 1723 if (UseTLAB) { 1724 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs); 1725 resize_all_tlabs(); 1726 } 1727 1728 metrics.snap_after(); 1729 1730 if (metrics.is_good_progress()) { 1731 _progress_last_gc.set(); 1732 } else { 1733 // Nothing to do. Tell the allocation path that we have failed to make 1734 // progress, and it can finally fail. 1735 _progress_last_gc.unset(); 1736 } 1737 } 1738 1739 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1740 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1741 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1742 // some phase, we have to upgrade the Degenerate GC to Full GC. 1743 1744 clear_cancelled_gc(); 1745 1746 ShenandoahMetricsSnapshot metrics; 1747 metrics.snap_before(); 1748 1749 switch (point) { 1750 case _degenerated_traversal: 1751 { 1752 // Drop the collection set. Note: this leaves some already forwarded objects 1753 // behind, which may be problematic, see comments for ShenandoahEvacAssist 1754 // workarounds in ShenandoahTraversalHeuristics. 1755 1756 ShenandoahHeapLocker locker(lock()); 1757 collection_set()->clear_current_index(); 1758 for (size_t i = 0; i < collection_set()->count(); i++) { 1759 ShenandoahHeapRegion* r = collection_set()->next(); 1760 r->make_regular_bypass(); 1761 } 1762 collection_set()->clear(); 1763 } 1764 op_final_traversal(); 1765 op_cleanup(); 1766 return; 1767 1768 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1769 // but enters it at different points, depending on which concurrent phase had 1770 // degenerated. 1771 1772 case _degenerated_outside_cycle: 1773 // We have degenerated from outside the cycle, which means something is bad with 1774 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1775 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1776 // we can do the most aggressive degen cycle, which includes processing references and 1777 // class unloading, unless those features are explicitly disabled. 1778 // 1779 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1780 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1781 set_process_references(heuristics()->can_process_references()); 1782 set_unload_classes(heuristics()->can_unload_classes()); 1783 1784 if (is_traversal_mode()) { 1785 // Not possible to degenerate from here, upgrade to Full GC right away. 1786 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1787 op_degenerated_fail(); 1788 return; 1789 } 1790 1791 op_reset(); 1792 1793 op_init_mark(); 1794 if (cancelled_gc()) { 1795 op_degenerated_fail(); 1796 return; 1797 } 1798 1799 case _degenerated_mark: 1800 op_final_mark(); 1801 if (cancelled_gc()) { 1802 op_degenerated_fail(); 1803 return; 1804 } 1805 1806 op_cleanup(); 1807 1808 case _degenerated_evac: 1809 // If heuristics thinks we should do the cycle, this flag would be set, 1810 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1811 if (is_evacuation_in_progress()) { 1812 1813 // Degeneration under oom-evac protocol might have left some objects in 1814 // collection set un-evacuated. Restart evacuation from the beginning to 1815 // capture all objects. For all the objects that are already evacuated, 1816 // it would be a simple check, which is supposed to be fast. This is also 1817 // safe to do even without degeneration, as CSet iterator is at beginning 1818 // in preparation for evacuation anyway. 1819 // 1820 // Before doing that, we need to make sure we never had any cset-pinned 1821 // regions. This may happen if allocation failure happened when evacuating 1822 // the about-to-be-pinned object, oom-evac protocol left the object in 1823 // the collection set, and then the pin reached the cset region. If we continue 1824 // the cycle here, we would trash the cset and alive objects in it. To avoid 1825 // it, we fail degeneration right away and slide into Full GC to recover. 1826 1827 { 1828 sync_pinned_region_status(); 1829 collection_set()->clear_current_index(); 1830 1831 ShenandoahHeapRegion* r; 1832 while ((r = collection_set()->next()) != NULL) { 1833 if (r->is_pinned()) { 1834 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1835 op_degenerated_fail(); 1836 return; 1837 } 1838 } 1839 1840 collection_set()->clear_current_index(); 1841 } 1842 1843 op_stw_evac(); 1844 if (cancelled_gc()) { 1845 op_degenerated_fail(); 1846 return; 1847 } 1848 } 1849 1850 // If heuristics thinks we should do the cycle, this flag would be set, 1851 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1852 if (has_forwarded_objects()) { 1853 op_init_updaterefs(); 1854 if (cancelled_gc()) { 1855 op_degenerated_fail(); 1856 return; 1857 } 1858 } 1859 1860 case _degenerated_updaterefs: 1861 if (has_forwarded_objects()) { 1862 op_final_updaterefs(); 1863 if (cancelled_gc()) { 1864 op_degenerated_fail(); 1865 return; 1866 } 1867 } 1868 1869 op_cleanup(); 1870 break; 1871 1872 default: 1873 ShouldNotReachHere(); 1874 } 1875 1876 if (ShenandoahVerify) { 1877 verifier()->verify_after_degenerated(); 1878 } 1879 1880 if (VerifyAfterGC) { 1881 Universe::verify(); 1882 } 1883 1884 metrics.snap_after(); 1885 1886 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 1887 // because that probably means the heap is overloaded and/or fragmented. 1888 if (!metrics.is_good_progress()) { 1889 _progress_last_gc.unset(); 1890 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1891 op_degenerated_futile(); 1892 } else { 1893 _progress_last_gc.set(); 1894 } 1895 } 1896 1897 void ShenandoahHeap::op_degenerated_fail() { 1898 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 1899 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1900 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1901 } 1902 1903 void ShenandoahHeap::op_degenerated_futile() { 1904 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1905 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1906 } 1907 1908 void ShenandoahHeap::force_satb_flush_all_threads() { 1909 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) { 1910 // No need to flush SATBs 1911 return; 1912 } 1913 1914 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1915 ShenandoahThreadLocalData::set_force_satb_flush(t, true); 1916 } 1917 // The threads are not "acquiring" their thread-local data, but it does not 1918 // hurt to "release" the updates here anyway. 1919 OrderAccess::fence(); 1920 } 1921 1922 void ShenandoahHeap::set_gc_state_all_threads(char state) { 1923 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1924 ShenandoahThreadLocalData::set_gc_state(t, state); 1925 } 1926 } 1927 1928 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1929 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1930 _gc_state.set_cond(mask, value); 1931 set_gc_state_all_threads(_gc_state.raw_value()); 1932 } 1933 1934 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1935 if (has_forwarded_objects()) { 1936 set_gc_state_mask(MARKING | UPDATEREFS, in_progress); 1937 } else { 1938 set_gc_state_mask(MARKING, in_progress); 1939 } 1940 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1941 } 1942 1943 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) { 1944 set_gc_state_mask(TRAVERSAL, in_progress); 1945 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1946 } 1947 1948 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1949 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1950 set_gc_state_mask(EVACUATION, in_progress); 1951 } 1952 1953 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) { 1954 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?"); 1955 if (in_progress) { 1956 _concurrent_root_in_progress.set(); 1957 } else { 1958 _concurrent_root_in_progress.unset(); 1959 } 1960 } 1961 1962 void ShenandoahHeap::ref_processing_init() { 1963 assert(_max_workers > 0, "Sanity"); 1964 1965 _ref_processor = 1966 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery 1967 ParallelRefProcEnabled, // MT processing 1968 _max_workers, // Degree of MT processing 1969 true, // MT discovery 1970 _max_workers, // Degree of MT discovery 1971 false, // Reference discovery is not atomic 1972 NULL, // No closure, should be installed before use 1973 true); // Scale worker threads 1974 1975 shenandoah_assert_rp_isalive_not_installed(); 1976 } 1977 1978 GCTracer* ShenandoahHeap::tracer() { 1979 return shenandoah_policy()->tracer(); 1980 } 1981 1982 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1983 return _free_set->used(); 1984 } 1985 1986 bool ShenandoahHeap::try_cancel_gc() { 1987 while (true) { 1988 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 1989 if (prev == CANCELLABLE) return true; 1990 else if (prev == CANCELLED) return false; 1991 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 1992 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 1993 if (Thread::current()->is_Java_thread()) { 1994 // We need to provide a safepoint here, otherwise we might 1995 // spin forever if a SP is pending. 1996 ThreadBlockInVM sp(JavaThread::current()); 1997 SpinPause(); 1998 } 1999 } 2000 } 2001 2002 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 2003 if (try_cancel_gc()) { 2004 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 2005 log_info(gc)("%s", msg.buffer()); 2006 Events::log(Thread::current(), "%s", msg.buffer()); 2007 } 2008 } 2009 2010 uint ShenandoahHeap::max_workers() { 2011 return _max_workers; 2012 } 2013 2014 void ShenandoahHeap::stop() { 2015 // The shutdown sequence should be able to terminate when GC is running. 2016 2017 // Step 0. Notify policy to disable event recording. 2018 _shenandoah_policy->record_shutdown(); 2019 2020 // Step 1. Notify control thread that we are in shutdown. 2021 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 2022 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 2023 control_thread()->prepare_for_graceful_shutdown(); 2024 2025 // Step 2. Notify GC workers that we are cancelling GC. 2026 cancel_gc(GCCause::_shenandoah_stop_vm); 2027 2028 // Step 3. Wait until GC worker exits normally. 2029 control_thread()->stop(); 2030 2031 // Step 4. Stop String Dedup thread if it is active 2032 if (ShenandoahStringDedup::is_enabled()) { 2033 ShenandoahStringDedup::stop(); 2034 } 2035 } 2036 2037 void ShenandoahHeap::stw_unload_classes(bool full_gc) { 2038 if (!unload_classes()) return; 2039 bool purged_class; 2040 2041 // Unload classes and purge SystemDictionary. 2042 { 2043 ShenandoahGCPhase phase(full_gc ? 2044 ShenandoahPhaseTimings::full_gc_purge_class_unload : 2045 ShenandoahPhaseTimings::purge_class_unload); 2046 purged_class = SystemDictionary::do_unloading(gc_timer()); 2047 } 2048 2049 { 2050 ShenandoahGCPhase phase(full_gc ? 2051 ShenandoahPhaseTimings::full_gc_purge_par : 2052 ShenandoahPhaseTimings::purge_par); 2053 ShenandoahIsAliveSelector is_alive; 2054 uint num_workers = _workers->active_workers(); 2055 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class); 2056 _workers->run_task(&unlink_task); 2057 } 2058 2059 { 2060 ShenandoahGCPhase phase(full_gc ? 2061 ShenandoahPhaseTimings::full_gc_purge_cldg : 2062 ShenandoahPhaseTimings::purge_cldg); 2063 ClassLoaderDataGraph::purge(); 2064 } 2065 // Resize and verify metaspace 2066 MetaspaceGC::compute_new_size(); 2067 MetaspaceUtils::verify_metrics(); 2068 } 2069 2070 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs), 2071 // so they should not have forwarded oops. 2072 // However, we do need to "null" dead oops in the roots, if can not be done 2073 // in concurrent cycles. 2074 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) { 2075 ShenandoahGCPhase root_phase(full_gc ? 2076 ShenandoahPhaseTimings::full_gc_purge : 2077 ShenandoahPhaseTimings::purge); 2078 uint num_workers = _workers->active_workers(); 2079 ShenandoahPhaseTimings::Phase timing_phase = full_gc ? 2080 ShenandoahPhaseTimings::full_gc_purge_par : 2081 ShenandoahPhaseTimings::purge_par; 2082 // Cleanup weak roots 2083 ShenandoahGCPhase phase(timing_phase); 2084 if (has_forwarded_objects()) { 2085 if (is_traversal_mode()) { 2086 ShenandoahForwardedIsAliveClosure is_alive; 2087 ShenandoahTraversalUpdateRefsClosure keep_alive; 2088 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahTraversalUpdateRefsClosure> 2089 cleaning_task(&is_alive, &keep_alive, num_workers); 2090 _workers->run_task(&cleaning_task); 2091 } else { 2092 ShenandoahForwardedIsAliveClosure is_alive; 2093 ShenandoahUpdateRefsClosure keep_alive; 2094 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure> 2095 cleaning_task(&is_alive, &keep_alive, num_workers); 2096 _workers->run_task(&cleaning_task); 2097 } 2098 } else { 2099 ShenandoahIsAliveClosure is_alive; 2100 #ifdef ASSERT 2101 ShenandoahAssertNotForwardedClosure verify_cl; 2102 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure> 2103 cleaning_task(&is_alive, &verify_cl, num_workers); 2104 #else 2105 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure> 2106 cleaning_task(&is_alive, &do_nothing_cl, num_workers); 2107 #endif 2108 _workers->run_task(&cleaning_task); 2109 } 2110 } 2111 2112 void ShenandoahHeap::parallel_cleaning(bool full_gc) { 2113 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2114 stw_process_weak_roots(full_gc); 2115 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2116 stw_unload_classes(full_gc); 2117 } 2118 } 2119 2120 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 2121 if (is_traversal_mode()) { 2122 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond); 2123 } else { 2124 set_gc_state_mask(HAS_FORWARDED, cond); 2125 } 2126 2127 } 2128 2129 void ShenandoahHeap::set_process_references(bool pr) { 2130 _process_references.set_cond(pr); 2131 } 2132 2133 void ShenandoahHeap::set_unload_classes(bool uc) { 2134 _unload_classes.set_cond(uc); 2135 } 2136 2137 bool ShenandoahHeap::process_references() const { 2138 return _process_references.is_set(); 2139 } 2140 2141 bool ShenandoahHeap::unload_classes() const { 2142 return _unload_classes.is_set(); 2143 } 2144 2145 address ShenandoahHeap::in_cset_fast_test_addr() { 2146 ShenandoahHeap* heap = ShenandoahHeap::heap(); 2147 assert(heap->collection_set() != NULL, "Sanity"); 2148 return (address) heap->collection_set()->biased_map_address(); 2149 } 2150 2151 address ShenandoahHeap::cancelled_gc_addr() { 2152 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 2153 } 2154 2155 address ShenandoahHeap::gc_state_addr() { 2156 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 2157 } 2158 2159 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 2160 return Atomic::load_acquire(&_bytes_allocated_since_gc_start); 2161 } 2162 2163 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 2164 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 2165 } 2166 2167 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 2168 _degenerated_gc_in_progress.set_cond(in_progress); 2169 } 2170 2171 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 2172 _full_gc_in_progress.set_cond(in_progress); 2173 } 2174 2175 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 2176 assert (is_full_gc_in_progress(), "should be"); 2177 _full_gc_move_in_progress.set_cond(in_progress); 2178 } 2179 2180 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 2181 set_gc_state_mask(UPDATEREFS, in_progress); 2182 } 2183 2184 void ShenandoahHeap::register_nmethod(nmethod* nm) { 2185 ShenandoahCodeRoots::register_nmethod(nm); 2186 } 2187 2188 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 2189 ShenandoahCodeRoots::unregister_nmethod(nm); 2190 } 2191 2192 void ShenandoahHeap::flush_nmethod(nmethod* nm) { 2193 ShenandoahCodeRoots::flush_nmethod(nm); 2194 } 2195 2196 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 2197 heap_region_containing(o)->record_pin(); 2198 return o; 2199 } 2200 2201 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 2202 heap_region_containing(o)->record_unpin(); 2203 } 2204 2205 void ShenandoahHeap::sync_pinned_region_status() { 2206 ShenandoahHeapLocker locker(lock()); 2207 2208 for (size_t i = 0; i < num_regions(); i++) { 2209 ShenandoahHeapRegion *r = get_region(i); 2210 if (r->is_active()) { 2211 if (r->is_pinned()) { 2212 if (r->pin_count() == 0) { 2213 r->make_unpinned(); 2214 } 2215 } else { 2216 if (r->pin_count() > 0) { 2217 r->make_pinned(); 2218 } 2219 } 2220 } 2221 } 2222 2223 assert_pinned_region_status(); 2224 } 2225 2226 #ifdef ASSERT 2227 void ShenandoahHeap::assert_pinned_region_status() { 2228 for (size_t i = 0; i < num_regions(); i++) { 2229 ShenandoahHeapRegion* r = get_region(i); 2230 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 2231 "Region " SIZE_FORMAT " pinning status is inconsistent", i); 2232 } 2233 } 2234 #endif 2235 2236 GCTimer* ShenandoahHeap::gc_timer() const { 2237 return _gc_timer; 2238 } 2239 2240 void ShenandoahHeap::prepare_concurrent_roots() { 2241 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2242 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 2243 set_concurrent_root_in_progress(true); 2244 } 2245 } 2246 2247 void ShenandoahHeap::prepare_concurrent_unloading() { 2248 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2249 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2250 _unloader.prepare(); 2251 } 2252 } 2253 2254 void ShenandoahHeap::finish_concurrent_unloading() { 2255 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2256 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2257 _unloader.finish(); 2258 } 2259 } 2260 2261 #ifdef ASSERT 2262 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 2263 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 2264 2265 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 2266 if (UseDynamicNumberOfGCThreads || 2267 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { 2268 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 2269 } else { 2270 // Use ParallelGCThreads inside safepoints 2271 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); 2272 } 2273 } else { 2274 if (UseDynamicNumberOfGCThreads || 2275 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { 2276 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2277 } else { 2278 // Use ConcGCThreads outside safepoints 2279 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2280 } 2281 } 2282 } 2283 #endif 2284 2285 ShenandoahVerifier* ShenandoahHeap::verifier() { 2286 guarantee(ShenandoahVerify, "Should be enabled"); 2287 assert (_verifier != NULL, "sanity"); 2288 return _verifier; 2289 } 2290 2291 template<class T> 2292 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2293 private: 2294 T cl; 2295 ShenandoahHeap* _heap; 2296 ShenandoahRegionIterator* _regions; 2297 bool _concurrent; 2298 public: 2299 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2300 AbstractGangTask("Concurrent Update References Task"), 2301 cl(T()), 2302 _heap(ShenandoahHeap::heap()), 2303 _regions(regions), 2304 _concurrent(concurrent) { 2305 } 2306 2307 void work(uint worker_id) { 2308 if (_concurrent) { 2309 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2310 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2311 do_work(); 2312 } else { 2313 ShenandoahParallelWorkerSession worker_session(worker_id); 2314 do_work(); 2315 } 2316 } 2317 2318 private: 2319 void do_work() { 2320 ShenandoahHeapRegion* r = _regions->next(); 2321 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2322 while (r != NULL) { 2323 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); 2324 assert (top_at_start_ur >= r->bottom(), "sanity"); 2325 if (r->is_active() && !r->is_cset()) { 2326 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); 2327 } 2328 if (ShenandoahPacing) { 2329 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); 2330 } 2331 if (_heap->check_cancelled_gc_and_yield(_concurrent)) { 2332 return; 2333 } 2334 r = _regions->next(); 2335 } 2336 } 2337 }; 2338 2339 void ShenandoahHeap::update_heap_references(bool concurrent) { 2340 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent); 2341 workers()->run_task(&task); 2342 } 2343 2344 void ShenandoahHeap::op_init_updaterefs() { 2345 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2346 2347 set_evacuation_in_progress(false); 2348 2349 { 2350 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs); 2351 retire_and_reset_gclabs(); 2352 } 2353 2354 if (ShenandoahVerify) { 2355 if (!is_degenerated_gc_in_progress()) { 2356 verifier()->verify_roots_no_forwarded_except(ShenandoahRootVerifier::ThreadRoots); 2357 } 2358 verifier()->verify_before_updaterefs(); 2359 } 2360 2361 set_update_refs_in_progress(true); 2362 2363 { 2364 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare); 2365 2366 make_parsable(true); 2367 for (uint i = 0; i < num_regions(); i++) { 2368 ShenandoahHeapRegion* r = get_region(i); 2369 r->set_concurrent_iteration_safe_limit(r->top()); 2370 } 2371 2372 // Reset iterator. 2373 _update_refs_iterator.reset(); 2374 } 2375 2376 if (ShenandoahPacing) { 2377 pacer()->setup_for_updaterefs(); 2378 } 2379 } 2380 2381 void ShenandoahHeap::op_final_updaterefs() { 2382 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2383 2384 finish_concurrent_unloading(); 2385 2386 // Check if there is left-over work, and finish it 2387 if (_update_refs_iterator.has_next()) { 2388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work); 2389 2390 // Finish updating references where we left off. 2391 clear_cancelled_gc(); 2392 update_heap_references(false); 2393 } 2394 2395 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2396 // everything. On degenerated paths, cancelled gc would not be set anyway. 2397 if (cancelled_gc()) { 2398 clear_cancelled_gc(); 2399 } 2400 assert(!cancelled_gc(), "Should have been done right before"); 2401 2402 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) { 2403 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots); 2404 } 2405 2406 if (is_degenerated_gc_in_progress()) { 2407 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 2408 } else { 2409 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots); 2410 } 2411 2412 // Has to be done before cset is clear 2413 if (ShenandoahVerify) { 2414 verifier()->verify_roots_in_to_space(); 2415 } 2416 2417 // Drop unnecessary "pinned" state from regions that does not have CP marks 2418 // anymore, as this would allow trashing them below. 2419 { 2420 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned); 2421 sync_pinned_region_status(); 2422 } 2423 2424 { 2425 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset); 2426 trash_cset_regions(); 2427 } 2428 2429 set_has_forwarded_objects(false); 2430 set_update_refs_in_progress(false); 2431 2432 if (ShenandoahVerify) { 2433 verifier()->verify_after_updaterefs(); 2434 } 2435 2436 if (VerifyAfterGC) { 2437 Universe::verify(); 2438 } 2439 2440 { 2441 ShenandoahHeapLocker locker(lock()); 2442 _free_set->rebuild(); 2443 } 2444 } 2445 2446 #ifdef ASSERT 2447 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { 2448 _lock.assert_owned_by_current_thread(); 2449 } 2450 2451 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { 2452 _lock.assert_not_owned_by_current_thread(); 2453 } 2454 2455 void ShenandoahHeap::assert_heaplock_or_safepoint() { 2456 _lock.assert_owned_by_current_thread_or_safepoint(); 2457 } 2458 #endif 2459 2460 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2461 print_on(st); 2462 print_heap_regions_on(st); 2463 } 2464 2465 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2466 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2467 2468 size_t regions_from = _bitmap_regions_per_slice * slice; 2469 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2470 for (size_t g = regions_from; g < regions_to; g++) { 2471 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2472 if (skip_self && g == r->region_number()) continue; 2473 if (get_region(g)->is_committed()) { 2474 return true; 2475 } 2476 } 2477 return false; 2478 } 2479 2480 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2481 assert_heaplock_owned_by_current_thread(); 2482 2483 // Bitmaps in special regions do not need commits 2484 if (_bitmap_region_special) { 2485 return true; 2486 } 2487 2488 if (is_bitmap_slice_committed(r, true)) { 2489 // Some other region from the group is already committed, meaning the bitmap 2490 // slice is already committed, we exit right away. 2491 return true; 2492 } 2493 2494 // Commit the bitmap slice: 2495 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2496 size_t off = _bitmap_bytes_per_slice * slice; 2497 size_t len = _bitmap_bytes_per_slice; 2498 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2499 return false; 2500 } 2501 return true; 2502 } 2503 2504 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2505 assert_heaplock_owned_by_current_thread(); 2506 2507 // Bitmaps in special regions do not need uncommits 2508 if (_bitmap_region_special) { 2509 return true; 2510 } 2511 2512 if (is_bitmap_slice_committed(r, true)) { 2513 // Some other region from the group is still committed, meaning the bitmap 2514 // slice is should stay committed, exit right away. 2515 return true; 2516 } 2517 2518 // Uncommit the bitmap slice: 2519 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2520 size_t off = _bitmap_bytes_per_slice * slice; 2521 size_t len = _bitmap_bytes_per_slice; 2522 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2523 return false; 2524 } 2525 return true; 2526 } 2527 2528 void ShenandoahHeap::safepoint_synchronize_begin() { 2529 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2530 SuspendibleThreadSet::synchronize(); 2531 } 2532 } 2533 2534 void ShenandoahHeap::safepoint_synchronize_end() { 2535 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2536 SuspendibleThreadSet::desynchronize(); 2537 } 2538 } 2539 2540 void ShenandoahHeap::vmop_entry_init_mark() { 2541 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2542 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2543 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2544 2545 try_inject_alloc_failure(); 2546 VM_ShenandoahInitMark op; 2547 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2548 } 2549 2550 void ShenandoahHeap::vmop_entry_final_mark() { 2551 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2552 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2553 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2554 2555 try_inject_alloc_failure(); 2556 VM_ShenandoahFinalMarkStartEvac op; 2557 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2558 } 2559 2560 void ShenandoahHeap::vmop_entry_final_evac() { 2561 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2562 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2563 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); 2564 2565 VM_ShenandoahFinalEvac op; 2566 VMThread::execute(&op); // jump to entry_final_evac under safepoint 2567 } 2568 2569 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2570 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2571 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2572 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2573 2574 try_inject_alloc_failure(); 2575 VM_ShenandoahInitUpdateRefs op; 2576 VMThread::execute(&op); 2577 } 2578 2579 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2580 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2581 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2582 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2583 2584 try_inject_alloc_failure(); 2585 VM_ShenandoahFinalUpdateRefs op; 2586 VMThread::execute(&op); 2587 } 2588 2589 void ShenandoahHeap::vmop_entry_init_traversal() { 2590 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2591 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2592 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross); 2593 2594 try_inject_alloc_failure(); 2595 VM_ShenandoahInitTraversalGC op; 2596 VMThread::execute(&op); 2597 } 2598 2599 void ShenandoahHeap::vmop_entry_final_traversal() { 2600 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2601 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2602 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross); 2603 2604 try_inject_alloc_failure(); 2605 VM_ShenandoahFinalTraversalGC op; 2606 VMThread::execute(&op); 2607 } 2608 2609 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2610 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2611 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2612 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2613 2614 try_inject_alloc_failure(); 2615 VM_ShenandoahFullGC op(cause); 2616 VMThread::execute(&op); 2617 } 2618 2619 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2620 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2621 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2622 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2623 2624 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2625 VMThread::execute(°enerated_gc); 2626 } 2627 2628 void ShenandoahHeap::entry_init_mark() { 2629 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2630 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2631 const char* msg = init_mark_event_message(); 2632 GCTraceTime(Info, gc) time(msg, gc_timer()); 2633 EventMark em("%s", msg); 2634 2635 ShenandoahWorkerScope scope(workers(), 2636 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2637 "init marking"); 2638 2639 op_init_mark(); 2640 } 2641 2642 void ShenandoahHeap::entry_final_mark() { 2643 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2644 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2645 const char* msg = final_mark_event_message(); 2646 GCTraceTime(Info, gc) time(msg, gc_timer()); 2647 EventMark em("%s", msg); 2648 2649 ShenandoahWorkerScope scope(workers(), 2650 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2651 "final marking"); 2652 2653 op_final_mark(); 2654 } 2655 2656 void ShenandoahHeap::entry_final_evac() { 2657 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2658 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); 2659 static const char* msg = "Pause Final Evac"; 2660 GCTraceTime(Info, gc) time(msg, gc_timer()); 2661 EventMark em("%s", msg); 2662 2663 op_final_evac(); 2664 } 2665 2666 void ShenandoahHeap::entry_init_updaterefs() { 2667 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2668 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2669 2670 static const char* msg = "Pause Init Update Refs"; 2671 GCTraceTime(Info, gc) time(msg, gc_timer()); 2672 EventMark em("%s", msg); 2673 2674 // No workers used in this phase, no setup required 2675 2676 op_init_updaterefs(); 2677 } 2678 2679 void ShenandoahHeap::entry_final_updaterefs() { 2680 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2681 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2682 2683 static const char* msg = "Pause Final Update Refs"; 2684 GCTraceTime(Info, gc) time(msg, gc_timer()); 2685 EventMark em("%s", msg); 2686 2687 ShenandoahWorkerScope scope(workers(), 2688 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2689 "final reference update"); 2690 2691 op_final_updaterefs(); 2692 } 2693 2694 void ShenandoahHeap::entry_init_traversal() { 2695 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2696 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc); 2697 2698 static const char* msg = "Pause Init Traversal"; 2699 GCTraceTime(Info, gc) time(msg, gc_timer()); 2700 EventMark em("%s", msg); 2701 2702 ShenandoahWorkerScope scope(workers(), 2703 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2704 "init traversal"); 2705 2706 op_init_traversal(); 2707 } 2708 2709 void ShenandoahHeap::entry_final_traversal() { 2710 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2711 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc); 2712 2713 static const char* msg = "Pause Final Traversal"; 2714 GCTraceTime(Info, gc) time(msg, gc_timer()); 2715 EventMark em("%s", msg); 2716 2717 ShenandoahWorkerScope scope(workers(), 2718 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2719 "final traversal"); 2720 2721 op_final_traversal(); 2722 } 2723 2724 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2725 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2726 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2727 2728 static const char* msg = "Pause Full"; 2729 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true); 2730 EventMark em("%s", msg); 2731 2732 ShenandoahWorkerScope scope(workers(), 2733 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2734 "full gc"); 2735 2736 op_full(cause); 2737 } 2738 2739 void ShenandoahHeap::entry_degenerated(int point) { 2740 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2741 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2742 2743 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2744 const char* msg = degen_event_message(dpoint); 2745 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2746 EventMark em("%s", msg); 2747 2748 ShenandoahWorkerScope scope(workers(), 2749 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2750 "stw degenerated gc"); 2751 2752 set_degenerated_gc_in_progress(true); 2753 op_degenerated(dpoint); 2754 set_degenerated_gc_in_progress(false); 2755 } 2756 2757 void ShenandoahHeap::entry_mark() { 2758 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2759 2760 const char* msg = conc_mark_event_message(); 2761 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2762 EventMark em("%s", msg); 2763 2764 ShenandoahWorkerScope scope(workers(), 2765 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2766 "concurrent marking"); 2767 2768 try_inject_alloc_failure(); 2769 op_mark(); 2770 } 2771 2772 void ShenandoahHeap::entry_evac() { 2773 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2774 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2775 2776 static const char* msg = "Concurrent evacuation"; 2777 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2778 EventMark em("%s", msg); 2779 2780 ShenandoahWorkerScope scope(workers(), 2781 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2782 "concurrent evacuation"); 2783 2784 try_inject_alloc_failure(); 2785 op_conc_evac(); 2786 } 2787 2788 void ShenandoahHeap::entry_updaterefs() { 2789 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2790 2791 static const char* msg = "Concurrent update references"; 2792 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2793 EventMark em("%s", msg); 2794 2795 ShenandoahWorkerScope scope(workers(), 2796 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2797 "concurrent reference update"); 2798 2799 try_inject_alloc_failure(); 2800 op_updaterefs(); 2801 } 2802 2803 void ShenandoahHeap::entry_roots() { 2804 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots); 2805 2806 static const char* msg = "Concurrent roots processing"; 2807 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2808 EventMark em("%s", msg); 2809 2810 ShenandoahWorkerScope scope(workers(), 2811 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(), 2812 "concurrent root processing"); 2813 2814 try_inject_alloc_failure(); 2815 op_roots(); 2816 } 2817 2818 void ShenandoahHeap::entry_cleanup() { 2819 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2820 2821 static const char* msg = "Concurrent cleanup"; 2822 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2823 EventMark em("%s", msg); 2824 2825 // This phase does not use workers, no need for setup 2826 2827 try_inject_alloc_failure(); 2828 op_cleanup(); 2829 } 2830 2831 void ShenandoahHeap::entry_reset() { 2832 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2833 2834 static const char* msg = "Concurrent reset"; 2835 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2836 EventMark em("%s", msg); 2837 2838 ShenandoahWorkerScope scope(workers(), 2839 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2840 "concurrent reset"); 2841 2842 try_inject_alloc_failure(); 2843 op_reset(); 2844 } 2845 2846 void ShenandoahHeap::entry_preclean() { 2847 if (ShenandoahPreclean && process_references()) { 2848 static const char* msg = "Concurrent precleaning"; 2849 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2850 EventMark em("%s", msg); 2851 2852 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2853 2854 ShenandoahWorkerScope scope(workers(), 2855 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2856 "concurrent preclean", 2857 /* check_workers = */ false); 2858 2859 try_inject_alloc_failure(); 2860 op_preclean(); 2861 } 2862 } 2863 2864 void ShenandoahHeap::entry_traversal() { 2865 static const char* msg = "Concurrent traversal"; 2866 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2867 EventMark em("%s", msg); 2868 2869 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2870 2871 ShenandoahWorkerScope scope(workers(), 2872 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(), 2873 "concurrent traversal"); 2874 2875 try_inject_alloc_failure(); 2876 op_traversal(); 2877 } 2878 2879 void ShenandoahHeap::entry_uncommit(double shrink_before) { 2880 static const char *msg = "Concurrent uncommit"; 2881 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2882 EventMark em("%s", msg); 2883 2884 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 2885 2886 op_uncommit(shrink_before); 2887 } 2888 2889 void ShenandoahHeap::try_inject_alloc_failure() { 2890 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2891 _inject_alloc_failure.set(); 2892 os::naked_short_sleep(1); 2893 if (cancelled_gc()) { 2894 log_info(gc)("Allocation failure was successfully injected"); 2895 } 2896 } 2897 } 2898 2899 bool ShenandoahHeap::should_inject_alloc_failure() { 2900 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2901 } 2902 2903 void ShenandoahHeap::initialize_serviceability() { 2904 _memory_pool = new ShenandoahMemoryPool(this); 2905 _cycle_memory_manager.add_pool(_memory_pool); 2906 _stw_memory_manager.add_pool(_memory_pool); 2907 } 2908 2909 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 2910 GrowableArray<GCMemoryManager*> memory_managers(2); 2911 memory_managers.append(&_cycle_memory_manager); 2912 memory_managers.append(&_stw_memory_manager); 2913 return memory_managers; 2914 } 2915 2916 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 2917 GrowableArray<MemoryPool*> memory_pools(1); 2918 memory_pools.append(_memory_pool); 2919 return memory_pools; 2920 } 2921 2922 MemoryUsage ShenandoahHeap::memory_usage() { 2923 return _memory_pool->get_memory_usage(); 2924 } 2925 2926 void ShenandoahHeap::enter_evacuation() { 2927 _oom_evac_handler.enter_evacuation(); 2928 } 2929 2930 void ShenandoahHeap::leave_evacuation() { 2931 _oom_evac_handler.leave_evacuation(); 2932 } 2933 2934 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2935 _heap(ShenandoahHeap::heap()), 2936 _index(0) {} 2937 2938 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2939 _heap(heap), 2940 _index(0) {} 2941 2942 void ShenandoahRegionIterator::reset() { 2943 _index = 0; 2944 } 2945 2946 bool ShenandoahRegionIterator::has_next() const { 2947 return _index < _heap->num_regions(); 2948 } 2949 2950 char ShenandoahHeap::gc_state() const { 2951 return _gc_state.raw_value(); 2952 } 2953 2954 void ShenandoahHeap::deduplicate_string(oop str) { 2955 assert(java_lang_String::is_instance(str), "invariant"); 2956 2957 if (ShenandoahStringDedup::is_enabled()) { 2958 ShenandoahStringDedup::deduplicate(str); 2959 } 2960 } 2961 2962 const char* ShenandoahHeap::init_mark_event_message() const { 2963 bool update_refs = has_forwarded_objects(); 2964 bool proc_refs = process_references(); 2965 bool unload_cls = unload_classes(); 2966 2967 if (update_refs && proc_refs && unload_cls) { 2968 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; 2969 } else if (update_refs && proc_refs) { 2970 return "Pause Init Mark (update refs) (process weakrefs)"; 2971 } else if (update_refs && unload_cls) { 2972 return "Pause Init Mark (update refs) (unload classes)"; 2973 } else if (proc_refs && unload_cls) { 2974 return "Pause Init Mark (process weakrefs) (unload classes)"; 2975 } else if (update_refs) { 2976 return "Pause Init Mark (update refs)"; 2977 } else if (proc_refs) { 2978 return "Pause Init Mark (process weakrefs)"; 2979 } else if (unload_cls) { 2980 return "Pause Init Mark (unload classes)"; 2981 } else { 2982 return "Pause Init Mark"; 2983 } 2984 } 2985 2986 const char* ShenandoahHeap::final_mark_event_message() const { 2987 bool update_refs = has_forwarded_objects(); 2988 bool proc_refs = process_references(); 2989 bool unload_cls = unload_classes(); 2990 2991 if (update_refs && proc_refs && unload_cls) { 2992 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; 2993 } else if (update_refs && proc_refs) { 2994 return "Pause Final Mark (update refs) (process weakrefs)"; 2995 } else if (update_refs && unload_cls) { 2996 return "Pause Final Mark (update refs) (unload classes)"; 2997 } else if (proc_refs && unload_cls) { 2998 return "Pause Final Mark (process weakrefs) (unload classes)"; 2999 } else if (update_refs) { 3000 return "Pause Final Mark (update refs)"; 3001 } else if (proc_refs) { 3002 return "Pause Final Mark (process weakrefs)"; 3003 } else if (unload_cls) { 3004 return "Pause Final Mark (unload classes)"; 3005 } else { 3006 return "Pause Final Mark"; 3007 } 3008 } 3009 3010 const char* ShenandoahHeap::conc_mark_event_message() const { 3011 bool update_refs = has_forwarded_objects(); 3012 bool proc_refs = process_references(); 3013 bool unload_cls = unload_classes(); 3014 3015 if (update_refs && proc_refs && unload_cls) { 3016 return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; 3017 } else if (update_refs && proc_refs) { 3018 return "Concurrent marking (update refs) (process weakrefs)"; 3019 } else if (update_refs && unload_cls) { 3020 return "Concurrent marking (update refs) (unload classes)"; 3021 } else if (proc_refs && unload_cls) { 3022 return "Concurrent marking (process weakrefs) (unload classes)"; 3023 } else if (update_refs) { 3024 return "Concurrent marking (update refs)"; 3025 } else if (proc_refs) { 3026 return "Concurrent marking (process weakrefs)"; 3027 } else if (unload_cls) { 3028 return "Concurrent marking (unload classes)"; 3029 } else { 3030 return "Concurrent marking"; 3031 } 3032 } 3033 3034 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 3035 switch (point) { 3036 case _degenerated_unset: 3037 return "Pause Degenerated GC (<UNSET>)"; 3038 case _degenerated_traversal: 3039 return "Pause Degenerated GC (Traversal)"; 3040 case _degenerated_outside_cycle: 3041 return "Pause Degenerated GC (Outside of Cycle)"; 3042 case _degenerated_mark: 3043 return "Pause Degenerated GC (Mark)"; 3044 case _degenerated_evac: 3045 return "Pause Degenerated GC (Evacuation)"; 3046 case _degenerated_updaterefs: 3047 return "Pause Degenerated GC (Update Refs)"; 3048 default: 3049 ShouldNotReachHere(); 3050 return "ERROR"; 3051 } 3052 } 3053 3054 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 3055 #ifdef ASSERT 3056 assert(_liveness_cache != NULL, "sanity"); 3057 assert(worker_id < _max_workers, "sanity"); 3058 for (uint i = 0; i < num_regions(); i++) { 3059 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 3060 } 3061 #endif 3062 return _liveness_cache[worker_id]; 3063 } 3064 3065 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 3066 assert(worker_id < _max_workers, "sanity"); 3067 assert(_liveness_cache != NULL, "sanity"); 3068 jushort* ld = _liveness_cache[worker_id]; 3069 for (uint i = 0; i < num_regions(); i++) { 3070 ShenandoahHeapRegion* r = get_region(i); 3071 jushort live = ld[i]; 3072 if (live > 0) { 3073 r->increase_live_data_gc_words(live); 3074 ld[i] = 0; 3075 } 3076 } 3077 }