1 /* 2 * Copyright (c) 2013, 2020, Red Hat, Inc. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 #include "memory/allocation.hpp" 27 #include "memory/universe.hpp" 28 29 #include "gc/shared/gcArguments.hpp" 30 #include "gc/shared/gcTimer.hpp" 31 #include "gc/shared/gcTraceTime.inline.hpp" 32 #include "gc/shared/locationPrinter.inline.hpp" 33 #include "gc/shared/memAllocator.hpp" 34 #include "gc/shared/oopStorageSet.hpp" 35 #include "gc/shared/plab.hpp" 36 37 #include "gc/shenandoah/shenandoahAllocTracker.hpp" 38 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 39 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 40 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 41 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 42 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" 43 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp" 44 #include "gc/shenandoah/shenandoahControlThread.hpp" 45 #include "gc/shenandoah/shenandoahFreeSet.hpp" 46 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 47 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 48 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 49 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 50 #include "gc/shenandoah/shenandoahMarkCompact.hpp" 51 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 52 #include "gc/shenandoah/shenandoahMemoryPool.hpp" 53 #include "gc/shenandoah/shenandoahMetrics.hpp" 54 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp" 55 #include "gc/shenandoah/shenandoahNormalMode.hpp" 56 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 57 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 58 #include "gc/shenandoah/shenandoahParallelCleaning.inline.hpp" 59 #include "gc/shenandoah/shenandoahPassiveMode.hpp" 60 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 61 #include "gc/shenandoah/shenandoahStringDedup.hpp" 62 #include "gc/shenandoah/shenandoahTaskqueue.hpp" 63 #include "gc/shenandoah/shenandoahTraversalMode.hpp" 64 #include "gc/shenandoah/shenandoahUtils.hpp" 65 #include "gc/shenandoah/shenandoahVerifier.hpp" 66 #include "gc/shenandoah/shenandoahCodeRoots.hpp" 67 #include "gc/shenandoah/shenandoahVMOperations.hpp" 68 #include "gc/shenandoah/shenandoahWorkGroup.hpp" 69 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp" 70 #if INCLUDE_JFR 71 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 72 #endif 73 74 #include "memory/metaspace.hpp" 75 #include "oops/compressedOops.inline.hpp" 76 #include "runtime/atomic.hpp" 77 #include "runtime/globals.hpp" 78 #include "runtime/interfaceSupport.inline.hpp" 79 #include "runtime/orderAccess.hpp" 80 #include "runtime/safepointMechanism.hpp" 81 #include "runtime/vmThread.hpp" 82 #include "services/mallocTracker.hpp" 83 #include "utilities/powerOfTwo.hpp" 84 85 #ifdef ASSERT 86 template <class T> 87 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) { 88 T o = RawAccess<>::oop_load(p); 89 if (! CompressedOops::is_null(o)) { 90 oop obj = CompressedOops::decode_not_null(o); 91 shenandoah_assert_not_forwarded(p, obj); 92 } 93 } 94 95 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); } 96 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); } 97 #endif 98 99 class ShenandoahPretouchHeapTask : public AbstractGangTask { 100 private: 101 ShenandoahRegionIterator _regions; 102 const size_t _page_size; 103 public: 104 ShenandoahPretouchHeapTask(size_t page_size) : 105 AbstractGangTask("Shenandoah Pretouch Heap"), 106 _page_size(page_size) {} 107 108 virtual void work(uint worker_id) { 109 ShenandoahHeapRegion* r = _regions.next(); 110 while (r != NULL) { 111 os::pretouch_memory(r->bottom(), r->end(), _page_size); 112 r = _regions.next(); 113 } 114 } 115 }; 116 117 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 118 private: 119 ShenandoahRegionIterator _regions; 120 char* _bitmap_base; 121 const size_t _bitmap_size; 122 const size_t _page_size; 123 public: 124 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 125 AbstractGangTask("Shenandoah Pretouch Bitmap"), 126 _bitmap_base(bitmap_base), 127 _bitmap_size(bitmap_size), 128 _page_size(page_size) {} 129 130 virtual void work(uint worker_id) { 131 ShenandoahHeapRegion* r = _regions.next(); 132 while (r != NULL) { 133 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 134 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 135 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 136 137 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 138 139 r = _regions.next(); 140 } 141 } 142 }; 143 144 jint ShenandoahHeap::initialize() { 145 initialize_heuristics(); 146 147 // 148 // Figure out heap sizing 149 // 150 151 size_t init_byte_size = InitialHeapSize; 152 size_t min_byte_size = MinHeapSize; 153 size_t max_byte_size = MaxHeapSize; 154 size_t heap_alignment = HeapAlignment; 155 156 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 157 158 if (ShenandoahAlwaysPreTouch) { 159 // Enabled pre-touch means the entire heap is committed right away. 160 init_byte_size = max_byte_size; 161 } 162 163 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 164 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 165 166 _num_regions = ShenandoahHeapRegion::region_count(); 167 168 size_t num_committed_regions = init_byte_size / reg_size_bytes; 169 num_committed_regions = MIN2(num_committed_regions, _num_regions); 170 assert(num_committed_regions <= _num_regions, "sanity"); 171 _initial_size = num_committed_regions * reg_size_bytes; 172 173 size_t num_min_regions = min_byte_size / reg_size_bytes; 174 num_min_regions = MIN2(num_min_regions, _num_regions); 175 assert(num_min_regions <= _num_regions, "sanity"); 176 _minimum_size = num_min_regions * reg_size_bytes; 177 178 _committed = _initial_size; 179 180 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 181 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 182 183 // 184 // Reserve and commit memory for heap 185 // 186 187 ReservedHeapSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 188 initialize_reserved_region(heap_rs); 189 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 190 _heap_region_special = heap_rs.special(); 191 192 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 193 "Misaligned heap: " PTR_FORMAT, p2i(base())); 194 195 #if SHENANDOAH_OPTIMIZED_OBJTASK 196 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 197 // Fail if we ever attempt to address more than we can. 198 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) { 199 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 200 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 201 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 202 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable()); 203 vm_exit_during_initialization("Fatal Error", buf); 204 } 205 #endif 206 207 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 208 if (!_heap_region_special) { 209 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 210 "Cannot commit heap memory"); 211 } 212 213 // 214 // Reserve and commit memory for bitmap(s) 215 // 216 217 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 218 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 219 220 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 221 222 guarantee(bitmap_bytes_per_region != 0, 223 "Bitmap bytes per region should not be zero"); 224 guarantee(is_power_of_2(bitmap_bytes_per_region), 225 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 226 227 if (bitmap_page_size > bitmap_bytes_per_region) { 228 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 229 _bitmap_bytes_per_slice = bitmap_page_size; 230 } else { 231 _bitmap_regions_per_slice = 1; 232 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 233 } 234 235 guarantee(_bitmap_regions_per_slice >= 1, 236 "Should have at least one region per slice: " SIZE_FORMAT, 237 _bitmap_regions_per_slice); 238 239 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 240 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 241 _bitmap_bytes_per_slice, bitmap_page_size); 242 243 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 244 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 245 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 246 _bitmap_region_special = bitmap.special(); 247 248 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 249 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 250 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 251 if (!_bitmap_region_special) { 252 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 253 "Cannot commit bitmap memory"); 254 } 255 256 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 257 258 if (ShenandoahVerify) { 259 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 260 if (!verify_bitmap.special()) { 261 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 262 "Cannot commit verification bitmap memory"); 263 } 264 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 265 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 266 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 267 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 268 } 269 270 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 271 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 272 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 273 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 274 _aux_bitmap_region_special = aux_bitmap.special(); 275 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 276 277 // 278 // Create regions and region sets 279 // 280 281 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 282 _free_set = new ShenandoahFreeSet(this, _num_regions); 283 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 284 285 { 286 ShenandoahHeapLocker locker(lock()); 287 288 size_t size_words = ShenandoahHeapRegion::region_size_words(); 289 290 for (size_t i = 0; i < _num_regions; i++) { 291 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; 292 bool is_committed = i < num_committed_regions; 293 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); 294 295 _marking_context->initialize_top_at_mark_start(r); 296 _regions[i] = r; 297 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 298 } 299 300 // Initialize to complete 301 _marking_context->mark_complete(); 302 303 _free_set->rebuild(); 304 } 305 306 if (ShenandoahAlwaysPreTouch) { 307 assert(!AlwaysPreTouch, "Should have been overridden"); 308 309 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 310 // before initialize() below zeroes it with initializing thread. For any given region, 311 // we touch the region and the corresponding bitmaps from the same thread. 312 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 313 314 size_t pretouch_heap_page_size = heap_page_size; 315 size_t pretouch_bitmap_page_size = bitmap_page_size; 316 317 #ifdef LINUX 318 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 319 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 320 // them into huge one. Therefore, we need to pretouch with smaller pages. 321 if (UseTransparentHugePages) { 322 pretouch_heap_page_size = (size_t)os::vm_page_size(); 323 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 324 } 325 #endif 326 327 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 328 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 329 330 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 331 _num_regions, pretouch_bitmap_page_size); 332 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 333 _workers->run_task(&bcl); 334 335 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 336 _num_regions, pretouch_heap_page_size); 337 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 338 _workers->run_task(&hcl); 339 } 340 341 // 342 // Initialize the rest of GC subsystems 343 // 344 345 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 346 for (uint worker = 0; worker < _max_workers; worker++) { 347 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 348 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 349 } 350 351 // There should probably be Shenandoah-specific options for these, 352 // just as there are G1-specific options. 353 { 354 ShenandoahSATBMarkQueueSet& satbqs = ShenandoahBarrierSet::satb_mark_queue_set(); 355 satbqs.set_process_completed_buffers_threshold(20); // G1SATBProcessCompletedThreshold 356 satbqs.set_buffer_enqueue_threshold_percentage(60); // G1SATBBufferEnqueueingThresholdPercent 357 } 358 359 _monitoring_support = new ShenandoahMonitoringSupport(this); 360 _phase_timings = new ShenandoahPhaseTimings(); 361 ShenandoahStringDedup::initialize(); 362 ShenandoahCodeRoots::initialize(); 363 364 if (ShenandoahAllocationTrace) { 365 _alloc_tracker = new ShenandoahAllocTracker(); 366 } 367 368 if (ShenandoahPacing) { 369 _pacer = new ShenandoahPacer(this); 370 _pacer->setup_for_idle(); 371 } else { 372 _pacer = NULL; 373 } 374 375 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ? 376 new ShenandoahTraversalGC(this, _num_regions) : 377 NULL; 378 379 _control_thread = new ShenandoahControlThread(); 380 381 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 382 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 383 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 384 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 385 ); 386 387 log_info(gc, init)("Safepointing mechanism: %s", 388 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" : 389 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown")); 390 391 return JNI_OK; 392 } 393 394 void ShenandoahHeap::initialize_heuristics() { 395 if (ShenandoahGCMode != NULL) { 396 if (strcmp(ShenandoahGCMode, "traversal") == 0) { 397 _gc_mode = new ShenandoahTraversalMode(); 398 } else if (strcmp(ShenandoahGCMode, "normal") == 0) { 399 _gc_mode = new ShenandoahNormalMode(); 400 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 401 _gc_mode = new ShenandoahPassiveMode(); 402 } else { 403 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 404 } 405 } else { 406 ShouldNotReachHere(); 407 } 408 _gc_mode->initialize_flags(); 409 _heuristics = _gc_mode->initialize_heuristics(); 410 411 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 412 vm_exit_during_initialization( 413 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 414 _heuristics->name())); 415 } 416 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 417 vm_exit_during_initialization( 418 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 419 _heuristics->name())); 420 } 421 log_info(gc, init)("Shenandoah heuristics: %s", 422 _heuristics->name()); 423 } 424 425 #ifdef _MSC_VER 426 #pragma warning( push ) 427 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 428 #endif 429 430 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 431 CollectedHeap(), 432 _initial_size(0), 433 _used(0), 434 _committed(0), 435 _bytes_allocated_since_gc_start(0), 436 _max_workers(MAX2(ConcGCThreads, ParallelGCThreads)), 437 _workers(NULL), 438 _safepoint_workers(NULL), 439 _heap_region_special(false), 440 _num_regions(0), 441 _regions(NULL), 442 _update_refs_iterator(this), 443 _control_thread(NULL), 444 _shenandoah_policy(policy), 445 _heuristics(NULL), 446 _free_set(NULL), 447 _scm(new ShenandoahConcurrentMark()), 448 _traversal_gc(NULL), 449 _full_gc(new ShenandoahMarkCompact()), 450 _pacer(NULL), 451 _verifier(NULL), 452 _alloc_tracker(NULL), 453 _phase_timings(NULL), 454 _monitoring_support(NULL), 455 _memory_pool(NULL), 456 _stw_memory_manager("Shenandoah Pauses", "end of GC pause"), 457 _cycle_memory_manager("Shenandoah Cycles", "end of GC cycle"), 458 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 459 _soft_ref_policy(), 460 _log_min_obj_alignment_in_bytes(LogMinObjAlignmentInBytes), 461 _ref_processor(NULL), 462 _marking_context(NULL), 463 _bitmap_size(0), 464 _bitmap_regions_per_slice(0), 465 _bitmap_bytes_per_slice(0), 466 _bitmap_region_special(false), 467 _aux_bitmap_region_special(false), 468 _liveness_cache(NULL), 469 _collection_set(NULL) 470 { 471 log_info(gc, init)("GC threads: " UINT32_FORMAT " parallel, " UINT32_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); 472 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); 473 474 BarrierSet::set_barrier_set(new ShenandoahBarrierSet(this)); 475 476 _max_workers = MAX2(_max_workers, 1U); 477 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, 478 /* are_GC_task_threads */ true, 479 /* are_ConcurrentGC_threads */ true); 480 if (_workers == NULL) { 481 vm_exit_during_initialization("Failed necessary allocation."); 482 } else { 483 _workers->initialize_workers(); 484 } 485 486 if (ShenandoahParallelSafepointThreads > 1) { 487 _safepoint_workers = new ShenandoahWorkGang("Safepoint Cleanup Thread", 488 ShenandoahParallelSafepointThreads, 489 /* are_GC_task_threads */ false, 490 /* are_ConcurrentGC_threads */ false); 491 _safepoint_workers->initialize_workers(); 492 } 493 } 494 495 #ifdef _MSC_VER 496 #pragma warning( pop ) 497 #endif 498 499 class ShenandoahResetBitmapTask : public AbstractGangTask { 500 private: 501 ShenandoahRegionIterator _regions; 502 503 public: 504 ShenandoahResetBitmapTask() : 505 AbstractGangTask("Parallel Reset Bitmap Task") {} 506 507 void work(uint worker_id) { 508 ShenandoahHeapRegion* region = _regions.next(); 509 ShenandoahHeap* heap = ShenandoahHeap::heap(); 510 ShenandoahMarkingContext* const ctx = heap->marking_context(); 511 while (region != NULL) { 512 if (heap->is_bitmap_slice_committed(region)) { 513 ctx->clear_bitmap(region); 514 } 515 region = _regions.next(); 516 } 517 } 518 }; 519 520 void ShenandoahHeap::reset_mark_bitmap() { 521 assert_gc_workers(_workers->active_workers()); 522 mark_incomplete_marking_context(); 523 524 ShenandoahResetBitmapTask task; 525 _workers->run_task(&task); 526 } 527 528 void ShenandoahHeap::print_on(outputStream* st) const { 529 st->print_cr("Shenandoah Heap"); 530 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 531 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 532 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 533 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 534 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 535 num_regions(), 536 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 537 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 538 539 st->print("Status: "); 540 if (has_forwarded_objects()) st->print("has forwarded objects, "); 541 if (is_concurrent_mark_in_progress()) st->print("marking, "); 542 if (is_evacuation_in_progress()) st->print("evacuating, "); 543 if (is_update_refs_in_progress()) st->print("updating refs, "); 544 if (is_concurrent_traversal_in_progress()) st->print("traversal, "); 545 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 546 if (is_full_gc_in_progress()) st->print("full gc, "); 547 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 548 if (is_concurrent_root_in_progress()) st->print("concurrent roots, "); 549 550 if (cancelled_gc()) { 551 st->print("cancelled"); 552 } else { 553 st->print("not cancelled"); 554 } 555 st->cr(); 556 557 st->print_cr("Reserved region:"); 558 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 559 p2i(reserved_region().start()), 560 p2i(reserved_region().end())); 561 562 ShenandoahCollectionSet* cset = collection_set(); 563 st->print_cr("Collection set:"); 564 if (cset != NULL) { 565 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 566 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 567 } else { 568 st->print_cr(" (NULL)"); 569 } 570 571 st->cr(); 572 MetaspaceUtils::print_on(st); 573 574 if (Verbose) { 575 print_heap_regions_on(st); 576 } 577 } 578 579 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 580 public: 581 void do_thread(Thread* thread) { 582 assert(thread != NULL, "Sanity"); 583 assert(thread->is_Worker_thread(), "Only worker thread expected"); 584 ShenandoahThreadLocalData::initialize_gclab(thread); 585 } 586 }; 587 588 void ShenandoahHeap::post_initialize() { 589 CollectedHeap::post_initialize(); 590 MutexLocker ml(Threads_lock); 591 592 ShenandoahInitWorkerGCLABClosure init_gclabs; 593 _workers->threads_do(&init_gclabs); 594 595 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 596 // Now, we will let WorkGang to initialize gclab when new worker is created. 597 _workers->set_initialize_gclab(); 598 599 _scm->initialize(_max_workers); 600 _full_gc->initialize(_gc_timer); 601 602 ref_processing_init(); 603 604 _heuristics->initialize(); 605 606 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 607 } 608 609 size_t ShenandoahHeap::used() const { 610 return Atomic::load_acquire(&_used); 611 } 612 613 size_t ShenandoahHeap::committed() const { 614 OrderAccess::acquire(); 615 return _committed; 616 } 617 618 void ShenandoahHeap::increase_committed(size_t bytes) { 619 assert_heaplock_or_safepoint(); 620 _committed += bytes; 621 } 622 623 void ShenandoahHeap::decrease_committed(size_t bytes) { 624 assert_heaplock_or_safepoint(); 625 _committed -= bytes; 626 } 627 628 void ShenandoahHeap::increase_used(size_t bytes) { 629 Atomic::add(&_used, bytes); 630 } 631 632 void ShenandoahHeap::set_used(size_t bytes) { 633 Atomic::release_store_fence(&_used, bytes); 634 } 635 636 void ShenandoahHeap::decrease_used(size_t bytes) { 637 assert(used() >= bytes, "never decrease heap size by more than we've left"); 638 Atomic::sub(&_used, bytes); 639 } 640 641 void ShenandoahHeap::increase_allocated(size_t bytes) { 642 Atomic::add(&_bytes_allocated_since_gc_start, bytes); 643 } 644 645 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 646 size_t bytes = words * HeapWordSize; 647 if (!waste) { 648 increase_used(bytes); 649 } 650 increase_allocated(bytes); 651 if (ShenandoahPacing) { 652 control_thread()->pacing_notify_alloc(words); 653 if (waste) { 654 pacer()->claim_for_alloc(words, true); 655 } 656 } 657 } 658 659 size_t ShenandoahHeap::capacity() const { 660 return committed(); 661 } 662 663 size_t ShenandoahHeap::max_capacity() const { 664 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 665 } 666 667 size_t ShenandoahHeap::min_capacity() const { 668 return _minimum_size; 669 } 670 671 size_t ShenandoahHeap::initial_capacity() const { 672 return _initial_size; 673 } 674 675 bool ShenandoahHeap::is_in(const void* p) const { 676 HeapWord* heap_base = (HeapWord*) base(); 677 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 678 return p >= heap_base && p < last_region_end; 679 } 680 681 void ShenandoahHeap::op_uncommit(double shrink_before) { 682 assert (ShenandoahUncommit, "should be enabled"); 683 684 // Application allocates from the beginning of the heap, and GC allocates at 685 // the end of it. It is more efficient to uncommit from the end, so that applications 686 // could enjoy the near committed regions. GC allocations are much less frequent, 687 // and therefore can accept the committing costs. 688 689 size_t count = 0; 690 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 691 ShenandoahHeapRegion* r = get_region(i - 1); 692 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 693 ShenandoahHeapLocker locker(lock()); 694 if (r->is_empty_committed()) { 695 // Do not uncommit below minimal capacity 696 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 697 break; 698 } 699 700 r->make_uncommitted(); 701 count++; 702 } 703 } 704 SpinPause(); // allow allocators to take the lock 705 } 706 707 if (count > 0) { 708 control_thread()->notify_heap_changed(); 709 } 710 } 711 712 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 713 // New object should fit the GCLAB size 714 size_t min_size = MAX2(size, PLAB::min_size()); 715 716 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 717 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 718 new_size = MIN2(new_size, PLAB::max_size()); 719 new_size = MAX2(new_size, PLAB::min_size()); 720 721 // Record new heuristic value even if we take any shortcut. This captures 722 // the case when moderately-sized objects always take a shortcut. At some point, 723 // heuristics should catch up with them. 724 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 725 726 if (new_size < size) { 727 // New size still does not fit the object. Fall back to shared allocation. 728 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 729 return NULL; 730 } 731 732 // Retire current GCLAB, and allocate a new one. 733 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 734 gclab->retire(); 735 736 size_t actual_size = 0; 737 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 738 if (gclab_buf == NULL) { 739 return NULL; 740 } 741 742 assert (size <= actual_size, "allocation should fit"); 743 744 if (ZeroTLAB) { 745 // ..and clear it. 746 Copy::zero_to_words(gclab_buf, actual_size); 747 } else { 748 // ...and zap just allocated object. 749 #ifdef ASSERT 750 // Skip mangling the space corresponding to the object header to 751 // ensure that the returned space is not considered parsable by 752 // any concurrent GC thread. 753 size_t hdr_size = oopDesc::header_size(); 754 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 755 #endif // ASSERT 756 } 757 gclab->set_buf(gclab_buf, actual_size); 758 return gclab->allocate(size); 759 } 760 761 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 762 size_t requested_size, 763 size_t* actual_size) { 764 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 765 HeapWord* res = allocate_memory(req); 766 if (res != NULL) { 767 *actual_size = req.actual_size(); 768 } else { 769 *actual_size = 0; 770 } 771 return res; 772 } 773 774 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 775 size_t word_size, 776 size_t* actual_size) { 777 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 778 HeapWord* res = allocate_memory(req); 779 if (res != NULL) { 780 *actual_size = req.actual_size(); 781 } else { 782 *actual_size = 0; 783 } 784 return res; 785 } 786 787 ShenandoahHeap* ShenandoahHeap::heap() { 788 CollectedHeap* heap = Universe::heap(); 789 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); 790 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap"); 791 return (ShenandoahHeap*) heap; 792 } 793 794 ShenandoahHeap* ShenandoahHeap::heap_no_check() { 795 CollectedHeap* heap = Universe::heap(); 796 return (ShenandoahHeap*) heap; 797 } 798 799 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 800 ShenandoahAllocTrace trace_alloc(req.size(), req.type()); 801 802 intptr_t pacer_epoch = 0; 803 bool in_new_region = false; 804 HeapWord* result = NULL; 805 806 if (req.is_mutator_alloc()) { 807 if (ShenandoahPacing) { 808 pacer()->pace_for_alloc(req.size()); 809 pacer_epoch = pacer()->epoch(); 810 } 811 812 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 813 result = allocate_memory_under_lock(req, in_new_region); 814 } 815 816 // Allocation failed, block until control thread reacted, then retry allocation. 817 // 818 // It might happen that one of the threads requesting allocation would unblock 819 // way later after GC happened, only to fail the second allocation, because 820 // other threads have already depleted the free storage. In this case, a better 821 // strategy is to try again, as long as GC makes progress. 822 // 823 // Then, we need to make sure the allocation was retried after at least one 824 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 825 826 size_t tries = 0; 827 828 while (result == NULL && _progress_last_gc.is_set()) { 829 tries++; 830 control_thread()->handle_alloc_failure(req.size()); 831 result = allocate_memory_under_lock(req, in_new_region); 832 } 833 834 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 835 tries++; 836 control_thread()->handle_alloc_failure(req.size()); 837 result = allocate_memory_under_lock(req, in_new_region); 838 } 839 840 } else { 841 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 842 result = allocate_memory_under_lock(req, in_new_region); 843 // Do not call handle_alloc_failure() here, because we cannot block. 844 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 845 } 846 847 if (in_new_region) { 848 control_thread()->notify_heap_changed(); 849 } 850 851 if (result != NULL) { 852 size_t requested = req.size(); 853 size_t actual = req.actual_size(); 854 855 assert (req.is_lab_alloc() || (requested == actual), 856 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 857 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 858 859 if (req.is_mutator_alloc()) { 860 notify_mutator_alloc_words(actual, false); 861 862 // If we requested more than we were granted, give the rest back to pacer. 863 // This only matters if we are in the same pacing epoch: do not try to unpace 864 // over the budget for the other phase. 865 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 866 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 867 } 868 } else { 869 increase_used(actual*HeapWordSize); 870 } 871 } 872 873 return result; 874 } 875 876 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 877 ShenandoahHeapLocker locker(lock()); 878 return _free_set->allocate(req, in_new_region); 879 } 880 881 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 882 bool* gc_overhead_limit_was_exceeded) { 883 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 884 return allocate_memory(req); 885 } 886 887 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 888 size_t size, 889 Metaspace::MetadataType mdtype) { 890 MetaWord* result; 891 892 // Inform metaspace OOM to GC heuristics if class unloading is possible. 893 if (heuristics()->can_unload_classes()) { 894 ShenandoahHeuristics* h = heuristics(); 895 h->record_metaspace_oom(); 896 } 897 898 // Expand and retry allocation 899 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 900 if (result != NULL) { 901 return result; 902 } 903 904 // Start full GC 905 collect(GCCause::_metadata_GC_clear_soft_refs); 906 907 // Retry allocation 908 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 909 if (result != NULL) { 910 return result; 911 } 912 913 // Expand and retry allocation 914 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 915 if (result != NULL) { 916 return result; 917 } 918 919 // Out of memory 920 return NULL; 921 } 922 923 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 924 private: 925 ShenandoahHeap* const _heap; 926 Thread* const _thread; 927 public: 928 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 929 _heap(heap), _thread(Thread::current()) {} 930 931 void do_object(oop p) { 932 shenandoah_assert_marked(NULL, p); 933 if (!p->is_forwarded()) { 934 _heap->evacuate_object(p, _thread); 935 } 936 } 937 }; 938 939 class ShenandoahEvacuationTask : public AbstractGangTask { 940 private: 941 ShenandoahHeap* const _sh; 942 ShenandoahCollectionSet* const _cs; 943 bool _concurrent; 944 public: 945 ShenandoahEvacuationTask(ShenandoahHeap* sh, 946 ShenandoahCollectionSet* cs, 947 bool concurrent) : 948 AbstractGangTask("Parallel Evacuation Task"), 949 _sh(sh), 950 _cs(cs), 951 _concurrent(concurrent) 952 {} 953 954 void work(uint worker_id) { 955 if (_concurrent) { 956 ShenandoahConcurrentWorkerSession worker_session(worker_id); 957 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 958 ShenandoahEvacOOMScope oom_evac_scope; 959 do_work(); 960 } else { 961 ShenandoahParallelWorkerSession worker_session(worker_id); 962 ShenandoahEvacOOMScope oom_evac_scope; 963 do_work(); 964 } 965 } 966 967 private: 968 void do_work() { 969 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 970 ShenandoahHeapRegion* r; 971 while ((r =_cs->claim_next()) != NULL) { 972 assert(r->has_live(), "Region " SIZE_FORMAT " should have been reclaimed early", r->region_number()); 973 _sh->marked_object_iterate(r, &cl); 974 975 if (ShenandoahPacing) { 976 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 977 } 978 979 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 980 break; 981 } 982 } 983 } 984 }; 985 986 void ShenandoahHeap::trash_cset_regions() { 987 ShenandoahHeapLocker locker(lock()); 988 989 ShenandoahCollectionSet* set = collection_set(); 990 ShenandoahHeapRegion* r; 991 set->clear_current_index(); 992 while ((r = set->next()) != NULL) { 993 r->make_trash(); 994 } 995 collection_set()->clear(); 996 } 997 998 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 999 st->print_cr("Heap Regions:"); 1000 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 1001 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 1002 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); 1003 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)"); 1004 1005 for (size_t i = 0; i < num_regions(); i++) { 1006 get_region(i)->print_on(st); 1007 } 1008 } 1009 1010 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 1011 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1012 1013 oop humongous_obj = oop(start->bottom()); 1014 size_t size = humongous_obj->size(); 1015 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1016 size_t index = start->region_number() + required_regions - 1; 1017 1018 assert(!start->has_live(), "liveness must be zero"); 1019 1020 for(size_t i = 0; i < required_regions; i++) { 1021 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1022 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1023 ShenandoahHeapRegion* region = get_region(index --); 1024 1025 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1026 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1027 1028 region->make_trash_immediate(); 1029 } 1030 } 1031 1032 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1033 public: 1034 void do_thread(Thread* thread) { 1035 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1036 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1037 gclab->retire(); 1038 } 1039 }; 1040 1041 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 1042 if (UseTLAB) { 1043 CollectedHeap::ensure_parsability(retire_tlabs); 1044 } 1045 ShenandoahRetireGCLABClosure cl; 1046 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1047 cl.do_thread(t); 1048 } 1049 workers()->threads_do(&cl); 1050 } 1051 1052 void ShenandoahHeap::resize_tlabs() { 1053 CollectedHeap::resize_all_tlabs(); 1054 } 1055 1056 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 1057 private: 1058 ShenandoahRootEvacuator* _rp; 1059 1060 public: 1061 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 1062 AbstractGangTask("Shenandoah evacuate and update roots"), 1063 _rp(rp) {} 1064 1065 void work(uint worker_id) { 1066 ShenandoahParallelWorkerSession worker_session(worker_id); 1067 ShenandoahEvacOOMScope oom_evac_scope; 1068 ShenandoahEvacuateUpdateRootsClosure<> cl; 1069 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 1070 _rp->roots_do(worker_id, &cl); 1071 } 1072 }; 1073 1074 void ShenandoahHeap::evacuate_and_update_roots() { 1075 #if COMPILER2_OR_JVMCI 1076 DerivedPointerTable::clear(); 1077 #endif 1078 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1079 { 1080 // Include concurrent roots if current cycle can not process those roots concurrently 1081 ShenandoahRootEvacuator rp(workers()->active_workers(), 1082 ShenandoahPhaseTimings::init_evac, 1083 !ShenandoahConcurrentRoots::should_do_concurrent_roots(), 1084 !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 1085 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 1086 workers()->run_task(&roots_task); 1087 } 1088 1089 #if COMPILER2_OR_JVMCI 1090 DerivedPointerTable::update_pointers(); 1091 #endif 1092 } 1093 1094 // Returns size in bytes 1095 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1096 if (ShenandoahElasticTLAB) { 1097 // With Elastic TLABs, return the max allowed size, and let the allocation path 1098 // figure out the safe size for current allocation. 1099 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1100 } else { 1101 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1102 } 1103 } 1104 1105 size_t ShenandoahHeap::max_tlab_size() const { 1106 // Returns size in words 1107 return ShenandoahHeapRegion::max_tlab_size_words(); 1108 } 1109 1110 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure { 1111 public: 1112 void do_thread(Thread* thread) { 1113 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1114 gclab->retire(); 1115 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1116 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1117 } 1118 } 1119 }; 1120 1121 void ShenandoahHeap::retire_and_reset_gclabs() { 1122 ShenandoahRetireAndResetGCLABClosure cl; 1123 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1124 cl.do_thread(t); 1125 } 1126 workers()->threads_do(&cl); 1127 } 1128 1129 void ShenandoahHeap::collect(GCCause::Cause cause) { 1130 control_thread()->request_gc(cause); 1131 } 1132 1133 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1134 //assert(false, "Shouldn't need to do full collections"); 1135 } 1136 1137 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1138 Space* sp = heap_region_containing(addr); 1139 if (sp != NULL) { 1140 return sp->block_start(addr); 1141 } 1142 return NULL; 1143 } 1144 1145 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1146 Space* sp = heap_region_containing(addr); 1147 return sp->block_is_obj(addr); 1148 } 1149 1150 bool ShenandoahHeap::print_location(outputStream* st, void* addr) const { 1151 return BlockLocationPrinter<ShenandoahHeap>::print_location(st, addr); 1152 } 1153 1154 jlong ShenandoahHeap::millis_since_last_gc() { 1155 double v = heuristics()->time_since_last_gc() * 1000; 1156 assert(0 <= v && v <= max_jlong, "value should fit: %f", v); 1157 return (jlong)v; 1158 } 1159 1160 void ShenandoahHeap::prepare_for_verify() { 1161 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) { 1162 make_parsable(false); 1163 } 1164 } 1165 1166 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1167 workers()->print_worker_threads_on(st); 1168 if (ShenandoahStringDedup::is_enabled()) { 1169 ShenandoahStringDedup::print_worker_threads_on(st); 1170 } 1171 } 1172 1173 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1174 workers()->threads_do(tcl); 1175 if (_safepoint_workers != NULL) { 1176 _safepoint_workers->threads_do(tcl); 1177 } 1178 if (ShenandoahStringDedup::is_enabled()) { 1179 ShenandoahStringDedup::threads_do(tcl); 1180 } 1181 } 1182 1183 void ShenandoahHeap::print_tracing_info() const { 1184 LogTarget(Info, gc, stats) lt; 1185 if (lt.is_enabled()) { 1186 ResourceMark rm; 1187 LogStream ls(lt); 1188 1189 phase_timings()->print_on(&ls); 1190 1191 ls.cr(); 1192 ls.cr(); 1193 1194 shenandoah_policy()->print_gc_stats(&ls); 1195 1196 ls.cr(); 1197 ls.cr(); 1198 1199 if (ShenandoahPacing) { 1200 pacer()->print_on(&ls); 1201 } 1202 1203 ls.cr(); 1204 ls.cr(); 1205 1206 if (ShenandoahAllocationTrace) { 1207 assert(alloc_tracker() != NULL, "Must be"); 1208 alloc_tracker()->print_on(&ls); 1209 } else { 1210 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); 1211 } 1212 } 1213 } 1214 1215 void ShenandoahHeap::verify(VerifyOption vo) { 1216 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1217 if (ShenandoahVerify) { 1218 verifier()->verify_generic(vo); 1219 } else { 1220 // TODO: Consider allocating verification bitmaps on demand, 1221 // and turn this on unconditionally. 1222 } 1223 } 1224 } 1225 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1226 return _free_set->capacity(); 1227 } 1228 1229 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1230 private: 1231 MarkBitMap* _bitmap; 1232 Stack<oop,mtGC>* _oop_stack; 1233 1234 template <class T> 1235 void do_oop_work(T* p) { 1236 T o = RawAccess<>::oop_load(p); 1237 if (!CompressedOops::is_null(o)) { 1238 oop obj = CompressedOops::decode_not_null(o); 1239 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 1240 if (fwd == NULL) { 1241 // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp. 1242 // 1243 // That operation walks the reachable objects on its own, storing the marking 1244 // wavefront in the object marks. When it is done, it calls the CollectedHeap 1245 // to iterate over all objects to clean up the mess. When it reaches here, 1246 // the Shenandoah fwdptr resolution code encounters the marked objects with 1247 // NULL forwardee. Trying to act on that would crash the VM. Or fail the 1248 // asserts, should we go for resolve_forwarded_pointer(obj). 1249 // 1250 // Therefore, we have to dodge it by doing the raw access to forwardee, and 1251 // assuming the object had no forwardee, if that thing is NULL. 1252 } else { 1253 obj = fwd; 1254 } 1255 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1256 if (!_bitmap->is_marked(obj)) { 1257 _bitmap->mark(obj); 1258 _oop_stack->push(obj); 1259 } 1260 } 1261 } 1262 public: 1263 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1264 _bitmap(bitmap), _oop_stack(oop_stack) {} 1265 void do_oop(oop* p) { do_oop_work(p); } 1266 void do_oop(narrowOop* p) { do_oop_work(p); } 1267 }; 1268 1269 /* 1270 * This is public API, used in preparation of object_iterate(). 1271 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1272 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1273 * control, we call SH::make_tlabs_parsable(). 1274 */ 1275 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1276 // No-op. 1277 } 1278 1279 /* 1280 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1281 * 1282 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1283 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1284 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1285 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1286 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1287 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1288 * wiped the bitmap in preparation for next marking). 1289 * 1290 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1291 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1292 * is allowed to report dead objects, but is not required to do so. 1293 */ 1294 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1295 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1296 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1297 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1298 return; 1299 } 1300 1301 // Reset bitmap 1302 _aux_bit_map.clear(); 1303 1304 Stack<oop,mtGC> oop_stack; 1305 1306 // First, we process GC roots according to current GC cycle. This populates the work stack with initial objects. 1307 ShenandoahHeapIterationRootScanner rp; 1308 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1309 1310 // When concurrent root is in progress, weak roots may contain dead oops, they should not be used 1311 // for root scanning. 1312 if (is_concurrent_root_in_progress()) { 1313 rp.strong_roots_do(&oops); 1314 } else { 1315 rp.roots_do(&oops); 1316 } 1317 1318 // Work through the oop stack to traverse heap. 1319 while (! oop_stack.is_empty()) { 1320 oop obj = oop_stack.pop(); 1321 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1322 cl->do_object(obj); 1323 obj->oop_iterate(&oops); 1324 } 1325 1326 assert(oop_stack.is_empty(), "should be empty"); 1327 1328 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1329 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1330 } 1331 } 1332 1333 // Keep alive an object that was loaded with AS_NO_KEEPALIVE. 1334 void ShenandoahHeap::keep_alive(oop obj) { 1335 if (is_concurrent_mark_in_progress()) { 1336 ShenandoahBarrierSet::barrier_set()->enqueue(obj); 1337 } 1338 } 1339 1340 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1341 for (size_t i = 0; i < num_regions(); i++) { 1342 ShenandoahHeapRegion* current = get_region(i); 1343 blk->heap_region_do(current); 1344 } 1345 } 1346 1347 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1348 private: 1349 ShenandoahHeap* const _heap; 1350 ShenandoahHeapRegionClosure* const _blk; 1351 1352 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t)); 1353 volatile size_t _index; 1354 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0); 1355 1356 public: 1357 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1358 AbstractGangTask("Parallel Region Task"), 1359 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1360 1361 void work(uint worker_id) { 1362 size_t stride = ShenandoahParallelRegionStride; 1363 1364 size_t max = _heap->num_regions(); 1365 while (_index < max) { 1366 size_t cur = Atomic::fetch_and_add(&_index, stride); 1367 size_t start = cur; 1368 size_t end = MIN2(cur + stride, max); 1369 if (start >= max) break; 1370 1371 for (size_t i = cur; i < end; i++) { 1372 ShenandoahHeapRegion* current = _heap->get_region(i); 1373 _blk->heap_region_do(current); 1374 } 1375 } 1376 } 1377 }; 1378 1379 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1380 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1381 if (num_regions() > ShenandoahParallelRegionStride) { 1382 ShenandoahParallelHeapRegionTask task(blk); 1383 workers()->run_task(&task); 1384 } else { 1385 heap_region_iterate(blk); 1386 } 1387 } 1388 1389 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { 1390 private: 1391 ShenandoahMarkingContext* const _ctx; 1392 public: 1393 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1394 1395 void heap_region_do(ShenandoahHeapRegion* r) { 1396 if (r->is_active()) { 1397 r->clear_live_data(); 1398 _ctx->capture_top_at_mark_start(r); 1399 } else { 1400 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1401 assert(_ctx->top_at_mark_start(r) == r->top(), 1402 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()); 1403 } 1404 } 1405 1406 bool is_thread_safe() { return true; } 1407 }; 1408 1409 void ShenandoahHeap::op_init_mark() { 1410 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1411 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1412 1413 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1414 assert(!marking_context()->is_complete(), "should not be complete"); 1415 1416 if (ShenandoahVerify) { 1417 verifier()->verify_before_concmark(); 1418 } 1419 1420 if (VerifyBeforeGC) { 1421 Universe::verify(); 1422 } 1423 1424 set_concurrent_mark_in_progress(true); 1425 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1426 { 1427 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1428 make_parsable(true); 1429 } 1430 1431 { 1432 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); 1433 ShenandoahClearLivenessClosure clc; 1434 parallel_heap_region_iterate(&clc); 1435 } 1436 1437 // Make above changes visible to worker threads 1438 OrderAccess::fence(); 1439 1440 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1441 1442 if (UseTLAB) { 1443 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1444 resize_tlabs(); 1445 } 1446 1447 if (ShenandoahPacing) { 1448 pacer()->setup_for_mark(); 1449 } 1450 } 1451 1452 void ShenandoahHeap::op_mark() { 1453 concurrent_mark()->mark_from_roots(); 1454 } 1455 1456 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { 1457 private: 1458 ShenandoahMarkingContext* const _ctx; 1459 public: 1460 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} 1461 1462 void heap_region_do(ShenandoahHeapRegion* r) { 1463 if (r->is_active()) { 1464 HeapWord *tams = _ctx->top_at_mark_start(r); 1465 HeapWord *top = r->top(); 1466 if (top > tams) { 1467 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1468 } 1469 } else { 1470 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1471 assert(_ctx->top_at_mark_start(r) == r->top(), 1472 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number()); 1473 } 1474 } 1475 1476 bool is_thread_safe() { return true; } 1477 }; 1478 1479 void ShenandoahHeap::op_final_mark() { 1480 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1481 1482 // It is critical that we 1483 // evacuate roots right after finishing marking, so that we don't 1484 // get unmarked objects in the roots. 1485 1486 if (!cancelled_gc()) { 1487 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); 1488 1489 // Marking is completed, deactivate SATB barrier 1490 set_concurrent_mark_in_progress(false); 1491 mark_complete_marking_context(); 1492 1493 parallel_cleaning(false /* full gc*/); 1494 1495 if (has_forwarded_objects()) { 1496 // Degen may be caused by failed evacuation of roots 1497 if (is_degenerated_gc_in_progress()) { 1498 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 1499 } else { 1500 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots); 1501 } 1502 set_has_forwarded_objects(false); 1503 } 1504 1505 if (ShenandoahVerify) { 1506 verifier()->verify_roots_no_forwarded(); 1507 } 1508 // All allocations past TAMS are implicitly live, adjust the region data. 1509 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1510 { 1511 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); 1512 ShenandoahCompleteLivenessClosure cl; 1513 parallel_heap_region_iterate(&cl); 1514 } 1515 1516 // Force the threads to reacquire their TLABs outside the collection set. 1517 { 1518 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs); 1519 make_parsable(true); 1520 } 1521 1522 // We are about to select the collection set, make sure it knows about 1523 // current pinning status. Also, this allows trashing more regions that 1524 // now have their pinning status dropped. 1525 { 1526 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned); 1527 sync_pinned_region_status(); 1528 } 1529 1530 // Trash the collection set left over from previous cycle, if any. 1531 { 1532 ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset); 1533 trash_cset_regions(); 1534 } 1535 1536 { 1537 ShenandoahGCPhase phase(ShenandoahPhaseTimings::prepare_evac); 1538 1539 ShenandoahHeapLocker locker(lock()); 1540 _collection_set->clear(); 1541 _free_set->clear(); 1542 1543 heuristics()->choose_collection_set(_collection_set); 1544 1545 _free_set->rebuild(); 1546 } 1547 1548 if (!is_degenerated_gc_in_progress()) { 1549 prepare_concurrent_roots(); 1550 prepare_concurrent_unloading(); 1551 } 1552 1553 // If collection set has candidates, start evacuation. 1554 // Otherwise, bypass the rest of the cycle. 1555 if (!collection_set()->is_empty()) { 1556 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1557 1558 if (ShenandoahVerify) { 1559 verifier()->verify_before_evacuation(); 1560 } 1561 1562 set_evacuation_in_progress(true); 1563 // From here on, we need to update references. 1564 set_has_forwarded_objects(true); 1565 1566 if (!is_degenerated_gc_in_progress()) { 1567 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1568 ShenandoahCodeRoots::arm_nmethods(); 1569 } 1570 evacuate_and_update_roots(); 1571 } 1572 1573 if (ShenandoahPacing) { 1574 pacer()->setup_for_evac(); 1575 } 1576 1577 if (ShenandoahVerify) { 1578 ShenandoahRootVerifier::RootTypes types = ShenandoahRootVerifier::None; 1579 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1580 types = ShenandoahRootVerifier::combine(ShenandoahRootVerifier::JNIHandleRoots, ShenandoahRootVerifier::WeakRoots); 1581 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::CLDGRoots); 1582 types = ShenandoahRootVerifier::combine(types, ShenandoahRootVerifier::StringDedupRoots); 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 ShenandoahConcurrentStringDedupRoots _dedup_roots; 1660 bool _include_weak_roots; 1661 1662 public: 1663 ShenandoahConcurrentRootsEvacUpdateTask(bool include_weak_roots) : 1664 AbstractGangTask("Shenandoah Evacuate/Update Concurrent Roots Task"), 1665 _include_weak_roots(include_weak_roots) { 1666 } 1667 1668 void work(uint worker_id) { 1669 ShenandoahEvacOOMScope oom; 1670 { 1671 // vm_roots and weak_roots are OopStorage backed roots, concurrent iteration 1672 // may race against OopStorage::release() calls. 1673 ShenandoahEvacUpdateOopStorageRootsClosure cl; 1674 _vm_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1675 1676 if (_include_weak_roots) { 1677 _weak_roots.oops_do<ShenandoahEvacUpdateOopStorageRootsClosure>(&cl); 1678 } 1679 } 1680 1681 { 1682 ShenandoahEvacuateUpdateRootsClosure<> cl; 1683 CLDToOopClosure clds(&cl, ClassLoaderData::_claim_strong); 1684 _cld_roots.cld_do(&clds); 1685 } 1686 1687 { 1688 ShenandoahForwardedIsAliveClosure is_alive; 1689 ShenandoahEvacuateUpdateRootsClosure<MO_RELEASE> keep_alive; 1690 _dedup_roots.oops_do(&is_alive, &keep_alive, worker_id); 1691 } 1692 } 1693 }; 1694 1695 class ShenandoahEvacUpdateCleanupOopStorageRootsClosure : public BasicOopIterateClosure { 1696 private: 1697 ShenandoahHeap* const _heap; 1698 ShenandoahMarkingContext* const _mark_context; 1699 bool _evac_in_progress; 1700 Thread* const _thread; 1701 size_t _dead_counter; 1702 1703 public: 1704 ShenandoahEvacUpdateCleanupOopStorageRootsClosure(); 1705 void do_oop(oop* p); 1706 void do_oop(narrowOop* p); 1707 1708 size_t dead_counter() const; 1709 void reset_dead_counter(); 1710 }; 1711 1712 ShenandoahEvacUpdateCleanupOopStorageRootsClosure::ShenandoahEvacUpdateCleanupOopStorageRootsClosure() : 1713 _heap(ShenandoahHeap::heap()), 1714 _mark_context(ShenandoahHeap::heap()->marking_context()), 1715 _evac_in_progress(ShenandoahHeap::heap()->is_evacuation_in_progress()), 1716 _thread(Thread::current()), 1717 _dead_counter(0) { 1718 } 1719 1720 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(oop* p) { 1721 const oop obj = RawAccess<>::oop_load(p); 1722 if (!CompressedOops::is_null(obj)) { 1723 if (!_mark_context->is_marked(obj)) { 1724 shenandoah_assert_correct(p, obj); 1725 oop old = Atomic::cmpxchg(p, obj, oop(NULL)); 1726 if (obj == old) { 1727 _dead_counter ++; 1728 } 1729 } else if (_evac_in_progress && _heap->in_collection_set(obj)) { 1730 oop resolved = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1731 if (resolved == obj) { 1732 resolved = _heap->evacuate_object(obj, _thread); 1733 } 1734 Atomic::cmpxchg(p, obj, resolved); 1735 assert(_heap->cancelled_gc() || 1736 _mark_context->is_marked(resolved) && !_heap->in_collection_set(resolved), 1737 "Sanity"); 1738 } 1739 } 1740 } 1741 1742 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::do_oop(narrowOop* p) { 1743 ShouldNotReachHere(); 1744 } 1745 1746 size_t ShenandoahEvacUpdateCleanupOopStorageRootsClosure::dead_counter() const { 1747 return _dead_counter; 1748 } 1749 1750 void ShenandoahEvacUpdateCleanupOopStorageRootsClosure::reset_dead_counter() { 1751 _dead_counter = 0; 1752 } 1753 1754 // This task not only evacuates/updates marked weak roots, but also "NULL" 1755 // dead weak roots. 1756 class ShenandoahConcurrentWeakRootsEvacUpdateTask : public AbstractGangTask { 1757 private: 1758 ShenandoahWeakRoot<true /*concurrent*/> _jni_roots; 1759 ShenandoahWeakRoot<true /*concurrent*/> _string_table_roots; 1760 ShenandoahWeakRoot<true /*concurrent*/> _resolved_method_table_roots; 1761 ShenandoahWeakRoot<true /*concurrent*/> _vm_roots; 1762 1763 public: 1764 ShenandoahConcurrentWeakRootsEvacUpdateTask() : 1765 AbstractGangTask("Shenandoah Concurrent Weak Root Task"), 1766 _jni_roots(OopStorageSet::jni_weak(), ShenandoahPhaseTimings::JNIWeakRoots), 1767 _string_table_roots(OopStorageSet::string_table_weak(), ShenandoahPhaseTimings::StringTableRoots), 1768 _resolved_method_table_roots(OopStorageSet::resolved_method_table_weak(), ShenandoahPhaseTimings::ResolvedMethodTableRoots), 1769 _vm_roots(OopStorageSet::vm_weak(), ShenandoahPhaseTimings::VMWeakRoots) { 1770 StringTable::reset_dead_counter(); 1771 ResolvedMethodTable::reset_dead_counter(); 1772 } 1773 1774 ~ShenandoahConcurrentWeakRootsEvacUpdateTask() { 1775 StringTable::finish_dead_counter(); 1776 ResolvedMethodTable::finish_dead_counter(); 1777 } 1778 1779 void work(uint worker_id) { 1780 ShenandoahEvacOOMScope oom; 1781 // jni_roots and weak_roots are OopStorage backed roots, concurrent iteration 1782 // may race against OopStorage::release() calls. 1783 ShenandoahEvacUpdateCleanupOopStorageRootsClosure cl; 1784 _jni_roots.oops_do(&cl, worker_id); 1785 _vm_roots.oops_do(&cl, worker_id); 1786 1787 cl.reset_dead_counter(); 1788 _string_table_roots.oops_do(&cl, worker_id); 1789 StringTable::inc_dead_counter(cl.dead_counter()); 1790 1791 cl.reset_dead_counter(); 1792 _resolved_method_table_roots.oops_do(&cl, worker_id); 1793 ResolvedMethodTable::inc_dead_counter(cl.dead_counter()); 1794 } 1795 }; 1796 1797 void ShenandoahHeap::op_roots() { 1798 if (is_concurrent_root_in_progress()) { 1799 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 1800 // Concurrent weak root processing 1801 ShenandoahConcurrentWeakRootsEvacUpdateTask task; 1802 workers()->run_task(&task); 1803 1804 _unloader.unload(); 1805 } 1806 1807 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 1808 ShenandoahConcurrentRootsEvacUpdateTask task(!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 1809 workers()->run_task(&task); 1810 } 1811 } 1812 1813 set_concurrent_root_in_progress(false); 1814 } 1815 1816 void ShenandoahHeap::op_reset() { 1817 reset_mark_bitmap(); 1818 } 1819 1820 void ShenandoahHeap::op_preclean() { 1821 concurrent_mark()->preclean_weak_refs(); 1822 } 1823 1824 void ShenandoahHeap::op_init_traversal() { 1825 traversal_gc()->init_traversal_collection(); 1826 } 1827 1828 void ShenandoahHeap::op_traversal() { 1829 traversal_gc()->concurrent_traversal_collection(); 1830 } 1831 1832 void ShenandoahHeap::op_final_traversal() { 1833 traversal_gc()->final_traversal_collection(); 1834 } 1835 1836 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1837 ShenandoahMetricsSnapshot metrics; 1838 metrics.snap_before(); 1839 1840 full_gc()->do_it(cause); 1841 if (UseTLAB) { 1842 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs); 1843 resize_all_tlabs(); 1844 } 1845 1846 metrics.snap_after(); 1847 1848 if (metrics.is_good_progress()) { 1849 _progress_last_gc.set(); 1850 } else { 1851 // Nothing to do. Tell the allocation path that we have failed to make 1852 // progress, and it can finally fail. 1853 _progress_last_gc.unset(); 1854 } 1855 } 1856 1857 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1858 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1859 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1860 // some phase, we have to upgrade the Degenerate GC to Full GC. 1861 1862 clear_cancelled_gc(); 1863 1864 ShenandoahMetricsSnapshot metrics; 1865 metrics.snap_before(); 1866 1867 switch (point) { 1868 case _degenerated_traversal: 1869 { 1870 // Drop the collection set. Note: this leaves some already forwarded objects 1871 // behind, which may be problematic, see comments for ShenandoahEvacAssist 1872 // workarounds in ShenandoahTraversalHeuristics. 1873 1874 ShenandoahHeapLocker locker(lock()); 1875 collection_set()->clear_current_index(); 1876 for (size_t i = 0; i < collection_set()->count(); i++) { 1877 ShenandoahHeapRegion* r = collection_set()->next(); 1878 r->make_regular_bypass(); 1879 } 1880 collection_set()->clear(); 1881 } 1882 op_final_traversal(); 1883 op_cleanup(); 1884 return; 1885 1886 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1887 // but enters it at different points, depending on which concurrent phase had 1888 // degenerated. 1889 1890 case _degenerated_outside_cycle: 1891 // We have degenerated from outside the cycle, which means something is bad with 1892 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1893 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1894 // we can do the most aggressive degen cycle, which includes processing references and 1895 // class unloading, unless those features are explicitly disabled. 1896 // 1897 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1898 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1899 set_process_references(heuristics()->can_process_references()); 1900 set_unload_classes(heuristics()->can_unload_classes()); 1901 1902 if (is_traversal_mode()) { 1903 // Not possible to degenerate from here, upgrade to Full GC right away. 1904 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1905 op_degenerated_fail(); 1906 return; 1907 } 1908 1909 op_reset(); 1910 1911 op_init_mark(); 1912 if (cancelled_gc()) { 1913 op_degenerated_fail(); 1914 return; 1915 } 1916 1917 case _degenerated_mark: 1918 op_final_mark(); 1919 if (cancelled_gc()) { 1920 op_degenerated_fail(); 1921 return; 1922 } 1923 1924 op_cleanup(); 1925 1926 case _degenerated_evac: 1927 // If heuristics thinks we should do the cycle, this flag would be set, 1928 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1929 if (is_evacuation_in_progress()) { 1930 1931 // Degeneration under oom-evac protocol might have left some objects in 1932 // collection set un-evacuated. Restart evacuation from the beginning to 1933 // capture all objects. For all the objects that are already evacuated, 1934 // it would be a simple check, which is supposed to be fast. This is also 1935 // safe to do even without degeneration, as CSet iterator is at beginning 1936 // in preparation for evacuation anyway. 1937 // 1938 // Before doing that, we need to make sure we never had any cset-pinned 1939 // regions. This may happen if allocation failure happened when evacuating 1940 // the about-to-be-pinned object, oom-evac protocol left the object in 1941 // the collection set, and then the pin reached the cset region. If we continue 1942 // the cycle here, we would trash the cset and alive objects in it. To avoid 1943 // it, we fail degeneration right away and slide into Full GC to recover. 1944 1945 { 1946 sync_pinned_region_status(); 1947 collection_set()->clear_current_index(); 1948 1949 ShenandoahHeapRegion* r; 1950 while ((r = collection_set()->next()) != NULL) { 1951 if (r->is_pinned()) { 1952 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1953 op_degenerated_fail(); 1954 return; 1955 } 1956 } 1957 1958 collection_set()->clear_current_index(); 1959 } 1960 1961 op_stw_evac(); 1962 if (cancelled_gc()) { 1963 op_degenerated_fail(); 1964 return; 1965 } 1966 } 1967 1968 // If heuristics thinks we should do the cycle, this flag would be set, 1969 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1970 if (has_forwarded_objects()) { 1971 op_init_updaterefs(); 1972 if (cancelled_gc()) { 1973 op_degenerated_fail(); 1974 return; 1975 } 1976 } 1977 1978 case _degenerated_updaterefs: 1979 if (has_forwarded_objects()) { 1980 op_final_updaterefs(); 1981 if (cancelled_gc()) { 1982 op_degenerated_fail(); 1983 return; 1984 } 1985 } 1986 1987 op_cleanup(); 1988 break; 1989 1990 default: 1991 ShouldNotReachHere(); 1992 } 1993 1994 if (ShenandoahVerify) { 1995 verifier()->verify_after_degenerated(); 1996 } 1997 1998 if (VerifyAfterGC) { 1999 Universe::verify(); 2000 } 2001 2002 metrics.snap_after(); 2003 2004 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 2005 // because that probably means the heap is overloaded and/or fragmented. 2006 if (!metrics.is_good_progress()) { 2007 _progress_last_gc.unset(); 2008 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 2009 op_degenerated_futile(); 2010 } else { 2011 _progress_last_gc.set(); 2012 } 2013 } 2014 2015 void ShenandoahHeap::op_degenerated_fail() { 2016 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 2017 shenandoah_policy()->record_degenerated_upgrade_to_full(); 2018 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 2019 } 2020 2021 void ShenandoahHeap::op_degenerated_futile() { 2022 shenandoah_policy()->record_degenerated_upgrade_to_full(); 2023 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 2024 } 2025 2026 void ShenandoahHeap::force_satb_flush_all_threads() { 2027 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) { 2028 // No need to flush SATBs 2029 return; 2030 } 2031 2032 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 2033 ShenandoahThreadLocalData::set_force_satb_flush(t, true); 2034 } 2035 // The threads are not "acquiring" their thread-local data, but it does not 2036 // hurt to "release" the updates here anyway. 2037 OrderAccess::fence(); 2038 } 2039 2040 void ShenandoahHeap::set_gc_state_all_threads(char state) { 2041 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 2042 ShenandoahThreadLocalData::set_gc_state(t, state); 2043 } 2044 } 2045 2046 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 2047 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 2048 _gc_state.set_cond(mask, value); 2049 set_gc_state_all_threads(_gc_state.raw_value()); 2050 } 2051 2052 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 2053 if (has_forwarded_objects()) { 2054 set_gc_state_mask(MARKING | UPDATEREFS, in_progress); 2055 } else { 2056 set_gc_state_mask(MARKING, in_progress); 2057 } 2058 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 2059 } 2060 2061 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) { 2062 set_gc_state_mask(TRAVERSAL, in_progress); 2063 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 2064 } 2065 2066 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 2067 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 2068 set_gc_state_mask(EVACUATION, in_progress); 2069 } 2070 2071 void ShenandoahHeap::set_concurrent_root_in_progress(bool in_progress) { 2072 assert(ShenandoahConcurrentRoots::can_do_concurrent_roots(), "Why set the flag?"); 2073 if (in_progress) { 2074 _concurrent_root_in_progress.set(); 2075 } else { 2076 _concurrent_root_in_progress.unset(); 2077 } 2078 } 2079 2080 void ShenandoahHeap::ref_processing_init() { 2081 assert(_max_workers > 0, "Sanity"); 2082 2083 _ref_processor = 2084 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery 2085 ParallelRefProcEnabled, // MT processing 2086 _max_workers, // Degree of MT processing 2087 true, // MT discovery 2088 _max_workers, // Degree of MT discovery 2089 false, // Reference discovery is not atomic 2090 NULL, // No closure, should be installed before use 2091 true); // Scale worker threads 2092 2093 shenandoah_assert_rp_isalive_not_installed(); 2094 } 2095 2096 GCTracer* ShenandoahHeap::tracer() { 2097 return shenandoah_policy()->tracer(); 2098 } 2099 2100 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 2101 return _free_set->used(); 2102 } 2103 2104 bool ShenandoahHeap::try_cancel_gc() { 2105 while (true) { 2106 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 2107 if (prev == CANCELLABLE) return true; 2108 else if (prev == CANCELLED) return false; 2109 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 2110 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 2111 if (Thread::current()->is_Java_thread()) { 2112 // We need to provide a safepoint here, otherwise we might 2113 // spin forever if a SP is pending. 2114 ThreadBlockInVM sp(JavaThread::current()); 2115 SpinPause(); 2116 } 2117 } 2118 } 2119 2120 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 2121 if (try_cancel_gc()) { 2122 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 2123 log_info(gc)("%s", msg.buffer()); 2124 Events::log(Thread::current(), "%s", msg.buffer()); 2125 } 2126 } 2127 2128 uint ShenandoahHeap::max_workers() { 2129 return _max_workers; 2130 } 2131 2132 void ShenandoahHeap::stop() { 2133 // The shutdown sequence should be able to terminate when GC is running. 2134 2135 // Step 0. Notify policy to disable event recording. 2136 _shenandoah_policy->record_shutdown(); 2137 2138 // Step 1. Notify control thread that we are in shutdown. 2139 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 2140 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 2141 control_thread()->prepare_for_graceful_shutdown(); 2142 2143 // Step 2. Notify GC workers that we are cancelling GC. 2144 cancel_gc(GCCause::_shenandoah_stop_vm); 2145 2146 // Step 3. Wait until GC worker exits normally. 2147 control_thread()->stop(); 2148 2149 // Step 4. Stop String Dedup thread if it is active 2150 if (ShenandoahStringDedup::is_enabled()) { 2151 ShenandoahStringDedup::stop(); 2152 } 2153 } 2154 2155 void ShenandoahHeap::stw_unload_classes(bool full_gc) { 2156 if (!unload_classes()) return; 2157 bool purged_class; 2158 2159 // Unload classes and purge SystemDictionary. 2160 { 2161 ShenandoahGCPhase phase(full_gc ? 2162 ShenandoahPhaseTimings::full_gc_purge_class_unload : 2163 ShenandoahPhaseTimings::purge_class_unload); 2164 purged_class = SystemDictionary::do_unloading(gc_timer()); 2165 } 2166 2167 { 2168 ShenandoahGCPhase phase(full_gc ? 2169 ShenandoahPhaseTimings::full_gc_purge_par : 2170 ShenandoahPhaseTimings::purge_par); 2171 ShenandoahIsAliveSelector is_alive; 2172 uint num_workers = _workers->active_workers(); 2173 ShenandoahClassUnloadingTask unlink_task(is_alive.is_alive_closure(), num_workers, purged_class); 2174 _workers->run_task(&unlink_task); 2175 } 2176 2177 { 2178 ShenandoahGCPhase phase(full_gc ? 2179 ShenandoahPhaseTimings::full_gc_purge_cldg : 2180 ShenandoahPhaseTimings::purge_cldg); 2181 ClassLoaderDataGraph::purge(); 2182 } 2183 // Resize and verify metaspace 2184 MetaspaceGC::compute_new_size(); 2185 MetaspaceUtils::verify_metrics(); 2186 } 2187 2188 // Weak roots are either pre-evacuated (final mark) or updated (final updaterefs), 2189 // so they should not have forwarded oops. 2190 // However, we do need to "null" dead oops in the roots, if can not be done 2191 // in concurrent cycles. 2192 void ShenandoahHeap::stw_process_weak_roots(bool full_gc) { 2193 ShenandoahGCPhase root_phase(full_gc ? 2194 ShenandoahPhaseTimings::full_gc_purge : 2195 ShenandoahPhaseTimings::purge); 2196 uint num_workers = _workers->active_workers(); 2197 ShenandoahPhaseTimings::Phase timing_phase = full_gc ? 2198 ShenandoahPhaseTimings::full_gc_purge_par : 2199 ShenandoahPhaseTimings::purge_par; 2200 // Cleanup weak roots 2201 ShenandoahGCPhase phase(timing_phase); 2202 phase_timings()->record_workers_start(timing_phase); 2203 if (has_forwarded_objects()) { 2204 if (is_traversal_mode()) { 2205 ShenandoahForwardedIsAliveClosure is_alive; 2206 ShenandoahTraversalUpdateRefsClosure keep_alive; 2207 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahTraversalUpdateRefsClosure> 2208 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2209 _workers->run_task(&cleaning_task); 2210 } else { 2211 ShenandoahForwardedIsAliveClosure is_alive; 2212 ShenandoahUpdateRefsClosure keep_alive; 2213 ShenandoahParallelWeakRootsCleaningTask<ShenandoahForwardedIsAliveClosure, ShenandoahUpdateRefsClosure> 2214 cleaning_task(&is_alive, &keep_alive, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2215 _workers->run_task(&cleaning_task); 2216 } 2217 } else { 2218 ShenandoahIsAliveClosure is_alive; 2219 #ifdef ASSERT 2220 ShenandoahAssertNotForwardedClosure verify_cl; 2221 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, ShenandoahAssertNotForwardedClosure> 2222 cleaning_task(&is_alive, &verify_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2223 #else 2224 ShenandoahParallelWeakRootsCleaningTask<ShenandoahIsAliveClosure, DoNothingClosure> 2225 cleaning_task(&is_alive, &do_nothing_cl, num_workers, !ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()); 2226 #endif 2227 _workers->run_task(&cleaning_task); 2228 } 2229 phase_timings()->record_workers_end(timing_phase); 2230 } 2231 2232 void ShenandoahHeap::parallel_cleaning(bool full_gc) { 2233 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2234 stw_process_weak_roots(full_gc); 2235 if (!ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2236 stw_unload_classes(full_gc); 2237 } 2238 } 2239 2240 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 2241 if (is_traversal_mode()) { 2242 set_gc_state_mask(HAS_FORWARDED | UPDATEREFS, cond); 2243 } else { 2244 set_gc_state_mask(HAS_FORWARDED, cond); 2245 } 2246 2247 } 2248 2249 void ShenandoahHeap::set_process_references(bool pr) { 2250 _process_references.set_cond(pr); 2251 } 2252 2253 void ShenandoahHeap::set_unload_classes(bool uc) { 2254 _unload_classes.set_cond(uc); 2255 } 2256 2257 bool ShenandoahHeap::process_references() const { 2258 return _process_references.is_set(); 2259 } 2260 2261 bool ShenandoahHeap::unload_classes() const { 2262 return _unload_classes.is_set(); 2263 } 2264 2265 address ShenandoahHeap::in_cset_fast_test_addr() { 2266 ShenandoahHeap* heap = ShenandoahHeap::heap(); 2267 assert(heap->collection_set() != NULL, "Sanity"); 2268 return (address) heap->collection_set()->biased_map_address(); 2269 } 2270 2271 address ShenandoahHeap::cancelled_gc_addr() { 2272 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 2273 } 2274 2275 address ShenandoahHeap::gc_state_addr() { 2276 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 2277 } 2278 2279 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 2280 return Atomic::load_acquire(&_bytes_allocated_since_gc_start); 2281 } 2282 2283 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 2284 Atomic::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 2285 } 2286 2287 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 2288 _degenerated_gc_in_progress.set_cond(in_progress); 2289 } 2290 2291 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 2292 _full_gc_in_progress.set_cond(in_progress); 2293 } 2294 2295 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 2296 assert (is_full_gc_in_progress(), "should be"); 2297 _full_gc_move_in_progress.set_cond(in_progress); 2298 } 2299 2300 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 2301 set_gc_state_mask(UPDATEREFS, in_progress); 2302 } 2303 2304 void ShenandoahHeap::register_nmethod(nmethod* nm) { 2305 ShenandoahCodeRoots::register_nmethod(nm); 2306 } 2307 2308 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 2309 ShenandoahCodeRoots::unregister_nmethod(nm); 2310 } 2311 2312 void ShenandoahHeap::flush_nmethod(nmethod* nm) { 2313 ShenandoahCodeRoots::flush_nmethod(nm); 2314 } 2315 2316 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 2317 heap_region_containing(o)->record_pin(); 2318 return o; 2319 } 2320 2321 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 2322 heap_region_containing(o)->record_unpin(); 2323 } 2324 2325 void ShenandoahHeap::sync_pinned_region_status() { 2326 ShenandoahHeapLocker locker(lock()); 2327 2328 for (size_t i = 0; i < num_regions(); i++) { 2329 ShenandoahHeapRegion *r = get_region(i); 2330 if (r->is_active()) { 2331 if (r->is_pinned()) { 2332 if (r->pin_count() == 0) { 2333 r->make_unpinned(); 2334 } 2335 } else { 2336 if (r->pin_count() > 0) { 2337 r->make_pinned(); 2338 } 2339 } 2340 } 2341 } 2342 2343 assert_pinned_region_status(); 2344 } 2345 2346 #ifdef ASSERT 2347 void ShenandoahHeap::assert_pinned_region_status() { 2348 for (size_t i = 0; i < num_regions(); i++) { 2349 ShenandoahHeapRegion* r = get_region(i); 2350 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 2351 "Region " SIZE_FORMAT " pinning status is inconsistent", i); 2352 } 2353 } 2354 #endif 2355 2356 GCTimer* ShenandoahHeap::gc_timer() const { 2357 return _gc_timer; 2358 } 2359 2360 void ShenandoahHeap::prepare_concurrent_roots() { 2361 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2362 if (ShenandoahConcurrentRoots::should_do_concurrent_roots()) { 2363 set_concurrent_root_in_progress(true); 2364 } 2365 } 2366 2367 void ShenandoahHeap::prepare_concurrent_unloading() { 2368 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2369 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2370 _unloader.prepare(); 2371 } 2372 } 2373 2374 void ShenandoahHeap::finish_concurrent_unloading() { 2375 assert(SafepointSynchronize::is_at_safepoint(), "Must be at a safepoint"); 2376 if (ShenandoahConcurrentRoots::should_do_concurrent_class_unloading()) { 2377 _unloader.finish(); 2378 } 2379 } 2380 2381 #ifdef ASSERT 2382 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 2383 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 2384 2385 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 2386 if (UseDynamicNumberOfGCThreads || 2387 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { 2388 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 2389 } else { 2390 // Use ParallelGCThreads inside safepoints 2391 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); 2392 } 2393 } else { 2394 if (UseDynamicNumberOfGCThreads || 2395 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { 2396 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2397 } else { 2398 // Use ConcGCThreads outside safepoints 2399 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2400 } 2401 } 2402 } 2403 #endif 2404 2405 ShenandoahVerifier* ShenandoahHeap::verifier() { 2406 guarantee(ShenandoahVerify, "Should be enabled"); 2407 assert (_verifier != NULL, "sanity"); 2408 return _verifier; 2409 } 2410 2411 template<class T> 2412 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2413 private: 2414 T cl; 2415 ShenandoahHeap* _heap; 2416 ShenandoahRegionIterator* _regions; 2417 bool _concurrent; 2418 public: 2419 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2420 AbstractGangTask("Concurrent Update References Task"), 2421 cl(T()), 2422 _heap(ShenandoahHeap::heap()), 2423 _regions(regions), 2424 _concurrent(concurrent) { 2425 } 2426 2427 void work(uint worker_id) { 2428 if (_concurrent) { 2429 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2430 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2431 do_work(); 2432 } else { 2433 ShenandoahParallelWorkerSession worker_session(worker_id); 2434 do_work(); 2435 } 2436 } 2437 2438 private: 2439 void do_work() { 2440 ShenandoahHeapRegion* r = _regions->next(); 2441 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2442 while (r != NULL) { 2443 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); 2444 assert (top_at_start_ur >= r->bottom(), "sanity"); 2445 if (r->is_active() && !r->is_cset()) { 2446 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); 2447 } 2448 if (ShenandoahPacing) { 2449 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); 2450 } 2451 if (_heap->check_cancelled_gc_and_yield(_concurrent)) { 2452 return; 2453 } 2454 r = _regions->next(); 2455 } 2456 } 2457 }; 2458 2459 void ShenandoahHeap::update_heap_references(bool concurrent) { 2460 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent); 2461 workers()->run_task(&task); 2462 } 2463 2464 void ShenandoahHeap::op_init_updaterefs() { 2465 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2466 2467 set_evacuation_in_progress(false); 2468 2469 { 2470 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_retire_gclabs); 2471 retire_and_reset_gclabs(); 2472 } 2473 2474 if (ShenandoahVerify) { 2475 if (!is_degenerated_gc_in_progress()) { 2476 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots); 2477 } 2478 verifier()->verify_before_updaterefs(); 2479 } 2480 2481 set_update_refs_in_progress(true); 2482 2483 { 2484 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare); 2485 2486 make_parsable(true); 2487 for (uint i = 0; i < num_regions(); i++) { 2488 ShenandoahHeapRegion* r = get_region(i); 2489 r->set_concurrent_iteration_safe_limit(r->top()); 2490 } 2491 2492 // Reset iterator. 2493 _update_refs_iterator.reset(); 2494 } 2495 2496 if (ShenandoahPacing) { 2497 pacer()->setup_for_updaterefs(); 2498 } 2499 } 2500 2501 void ShenandoahHeap::op_final_updaterefs() { 2502 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2503 2504 finish_concurrent_unloading(); 2505 2506 // Check if there is left-over work, and finish it 2507 if (_update_refs_iterator.has_next()) { 2508 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work); 2509 2510 // Finish updating references where we left off. 2511 clear_cancelled_gc(); 2512 update_heap_references(false); 2513 } 2514 2515 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2516 // everything. On degenerated paths, cancelled gc would not be set anyway. 2517 if (cancelled_gc()) { 2518 clear_cancelled_gc(); 2519 } 2520 assert(!cancelled_gc(), "Should have been done right before"); 2521 2522 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) { 2523 verifier()->verify_roots_in_to_space_except(ShenandoahRootVerifier::ThreadRoots); 2524 } 2525 2526 if (is_degenerated_gc_in_progress()) { 2527 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 2528 } else { 2529 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots); 2530 } 2531 2532 // Has to be done before cset is clear 2533 if (ShenandoahVerify) { 2534 verifier()->verify_roots_in_to_space(); 2535 } 2536 2537 // Drop unnecessary "pinned" state from regions that does not have CP marks 2538 // anymore, as this would allow trashing them below. 2539 { 2540 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned); 2541 sync_pinned_region_status(); 2542 } 2543 2544 { 2545 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset); 2546 trash_cset_regions(); 2547 } 2548 2549 set_has_forwarded_objects(false); 2550 set_update_refs_in_progress(false); 2551 2552 if (ShenandoahVerify) { 2553 verifier()->verify_after_updaterefs(); 2554 } 2555 2556 if (VerifyAfterGC) { 2557 Universe::verify(); 2558 } 2559 2560 { 2561 ShenandoahHeapLocker locker(lock()); 2562 _free_set->rebuild(); 2563 } 2564 } 2565 2566 #ifdef ASSERT 2567 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { 2568 _lock.assert_owned_by_current_thread(); 2569 } 2570 2571 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { 2572 _lock.assert_not_owned_by_current_thread(); 2573 } 2574 2575 void ShenandoahHeap::assert_heaplock_or_safepoint() { 2576 _lock.assert_owned_by_current_thread_or_safepoint(); 2577 } 2578 #endif 2579 2580 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2581 print_on(st); 2582 print_heap_regions_on(st); 2583 } 2584 2585 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2586 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2587 2588 size_t regions_from = _bitmap_regions_per_slice * slice; 2589 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2590 for (size_t g = regions_from; g < regions_to; g++) { 2591 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2592 if (skip_self && g == r->region_number()) continue; 2593 if (get_region(g)->is_committed()) { 2594 return true; 2595 } 2596 } 2597 return false; 2598 } 2599 2600 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2601 assert_heaplock_owned_by_current_thread(); 2602 2603 // Bitmaps in special regions do not need commits 2604 if (_bitmap_region_special) { 2605 return true; 2606 } 2607 2608 if (is_bitmap_slice_committed(r, true)) { 2609 // Some other region from the group is already committed, meaning the bitmap 2610 // slice is already committed, we exit right away. 2611 return true; 2612 } 2613 2614 // Commit the bitmap slice: 2615 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2616 size_t off = _bitmap_bytes_per_slice * slice; 2617 size_t len = _bitmap_bytes_per_slice; 2618 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2619 return false; 2620 } 2621 return true; 2622 } 2623 2624 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2625 assert_heaplock_owned_by_current_thread(); 2626 2627 // Bitmaps in special regions do not need uncommits 2628 if (_bitmap_region_special) { 2629 return true; 2630 } 2631 2632 if (is_bitmap_slice_committed(r, true)) { 2633 // Some other region from the group is still committed, meaning the bitmap 2634 // slice is should stay committed, exit right away. 2635 return true; 2636 } 2637 2638 // Uncommit the bitmap slice: 2639 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2640 size_t off = _bitmap_bytes_per_slice * slice; 2641 size_t len = _bitmap_bytes_per_slice; 2642 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2643 return false; 2644 } 2645 return true; 2646 } 2647 2648 void ShenandoahHeap::safepoint_synchronize_begin() { 2649 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2650 SuspendibleThreadSet::synchronize(); 2651 } 2652 } 2653 2654 void ShenandoahHeap::safepoint_synchronize_end() { 2655 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2656 SuspendibleThreadSet::desynchronize(); 2657 } 2658 } 2659 2660 void ShenandoahHeap::vmop_entry_init_mark() { 2661 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2662 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2663 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2664 2665 try_inject_alloc_failure(); 2666 VM_ShenandoahInitMark op; 2667 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2668 } 2669 2670 void ShenandoahHeap::vmop_entry_final_mark() { 2671 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2672 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2673 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2674 2675 try_inject_alloc_failure(); 2676 VM_ShenandoahFinalMarkStartEvac op; 2677 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2678 } 2679 2680 void ShenandoahHeap::vmop_entry_final_evac() { 2681 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2682 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2683 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); 2684 2685 VM_ShenandoahFinalEvac op; 2686 VMThread::execute(&op); // jump to entry_final_evac under safepoint 2687 } 2688 2689 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2690 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2691 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2692 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2693 2694 try_inject_alloc_failure(); 2695 VM_ShenandoahInitUpdateRefs op; 2696 VMThread::execute(&op); 2697 } 2698 2699 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2700 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2701 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2702 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2703 2704 try_inject_alloc_failure(); 2705 VM_ShenandoahFinalUpdateRefs op; 2706 VMThread::execute(&op); 2707 } 2708 2709 void ShenandoahHeap::vmop_entry_init_traversal() { 2710 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2711 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2712 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross); 2713 2714 try_inject_alloc_failure(); 2715 VM_ShenandoahInitTraversalGC op; 2716 VMThread::execute(&op); 2717 } 2718 2719 void ShenandoahHeap::vmop_entry_final_traversal() { 2720 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2721 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2722 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross); 2723 2724 try_inject_alloc_failure(); 2725 VM_ShenandoahFinalTraversalGC op; 2726 VMThread::execute(&op); 2727 } 2728 2729 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2730 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2731 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2732 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2733 2734 try_inject_alloc_failure(); 2735 VM_ShenandoahFullGC op(cause); 2736 VMThread::execute(&op); 2737 } 2738 2739 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2740 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2741 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2742 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2743 2744 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2745 VMThread::execute(°enerated_gc); 2746 } 2747 2748 void ShenandoahHeap::entry_init_mark() { 2749 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2750 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2751 const char* msg = init_mark_event_message(); 2752 GCTraceTime(Info, gc) time(msg, gc_timer()); 2753 EventMark em("%s", msg); 2754 2755 ShenandoahWorkerScope scope(workers(), 2756 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2757 "init marking"); 2758 2759 op_init_mark(); 2760 } 2761 2762 void ShenandoahHeap::entry_final_mark() { 2763 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2764 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2765 const char* msg = final_mark_event_message(); 2766 GCTraceTime(Info, gc) time(msg, gc_timer()); 2767 EventMark em("%s", msg); 2768 2769 ShenandoahWorkerScope scope(workers(), 2770 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2771 "final marking"); 2772 2773 op_final_mark(); 2774 } 2775 2776 void ShenandoahHeap::entry_final_evac() { 2777 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2778 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); 2779 static const char* msg = "Pause Final Evac"; 2780 GCTraceTime(Info, gc) time(msg, gc_timer()); 2781 EventMark em("%s", msg); 2782 2783 op_final_evac(); 2784 } 2785 2786 void ShenandoahHeap::entry_init_updaterefs() { 2787 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2788 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2789 2790 static const char* msg = "Pause Init Update Refs"; 2791 GCTraceTime(Info, gc) time(msg, gc_timer()); 2792 EventMark em("%s", msg); 2793 2794 // No workers used in this phase, no setup required 2795 2796 op_init_updaterefs(); 2797 } 2798 2799 void ShenandoahHeap::entry_final_updaterefs() { 2800 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2801 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2802 2803 static const char* msg = "Pause Final Update Refs"; 2804 GCTraceTime(Info, gc) time(msg, gc_timer()); 2805 EventMark em("%s", msg); 2806 2807 ShenandoahWorkerScope scope(workers(), 2808 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2809 "final reference update"); 2810 2811 op_final_updaterefs(); 2812 } 2813 2814 void ShenandoahHeap::entry_init_traversal() { 2815 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2816 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc); 2817 2818 static const char* msg = init_traversal_event_message(); 2819 GCTraceTime(Info, gc) time(msg, gc_timer()); 2820 EventMark em("%s", msg); 2821 2822 ShenandoahWorkerScope scope(workers(), 2823 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2824 "init traversal"); 2825 2826 op_init_traversal(); 2827 } 2828 2829 void ShenandoahHeap::entry_final_traversal() { 2830 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2831 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc); 2832 2833 static const char* msg = final_traversal_event_message(); 2834 GCTraceTime(Info, gc) time(msg, gc_timer()); 2835 EventMark em("%s", msg); 2836 2837 ShenandoahWorkerScope scope(workers(), 2838 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2839 "final traversal"); 2840 2841 op_final_traversal(); 2842 } 2843 2844 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2845 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2846 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2847 2848 static const char* msg = "Pause Full"; 2849 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true); 2850 EventMark em("%s", msg); 2851 2852 ShenandoahWorkerScope scope(workers(), 2853 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2854 "full gc"); 2855 2856 op_full(cause); 2857 } 2858 2859 void ShenandoahHeap::entry_degenerated(int point) { 2860 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2861 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2862 2863 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2864 const char* msg = degen_event_message(dpoint); 2865 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2866 EventMark em("%s", msg); 2867 2868 ShenandoahWorkerScope scope(workers(), 2869 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2870 "stw degenerated gc"); 2871 2872 set_degenerated_gc_in_progress(true); 2873 op_degenerated(dpoint); 2874 set_degenerated_gc_in_progress(false); 2875 } 2876 2877 void ShenandoahHeap::entry_mark() { 2878 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2879 2880 const char* msg = conc_mark_event_message(); 2881 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2882 EventMark em("%s", msg); 2883 2884 ShenandoahWorkerScope scope(workers(), 2885 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2886 "concurrent marking"); 2887 2888 try_inject_alloc_failure(); 2889 op_mark(); 2890 } 2891 2892 void ShenandoahHeap::entry_evac() { 2893 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2894 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2895 2896 static const char* msg = "Concurrent evacuation"; 2897 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2898 EventMark em("%s", msg); 2899 2900 ShenandoahWorkerScope scope(workers(), 2901 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2902 "concurrent evacuation"); 2903 2904 try_inject_alloc_failure(); 2905 op_conc_evac(); 2906 } 2907 2908 void ShenandoahHeap::entry_updaterefs() { 2909 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2910 2911 static const char* msg = "Concurrent update references"; 2912 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2913 EventMark em("%s", msg); 2914 2915 ShenandoahWorkerScope scope(workers(), 2916 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2917 "concurrent reference update"); 2918 2919 try_inject_alloc_failure(); 2920 op_updaterefs(); 2921 } 2922 2923 void ShenandoahHeap::entry_roots() { 2924 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_roots); 2925 2926 static const char* msg = "Concurrent roots processing"; 2927 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2928 EventMark em("%s", msg); 2929 2930 ShenandoahWorkerScope scope(workers(), 2931 ShenandoahWorkerPolicy::calc_workers_for_conc_root_processing(), 2932 "concurrent root processing"); 2933 2934 try_inject_alloc_failure(); 2935 op_roots(); 2936 } 2937 2938 void ShenandoahHeap::entry_cleanup() { 2939 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2940 2941 static const char* msg = "Concurrent cleanup"; 2942 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2943 EventMark em("%s", msg); 2944 2945 // This phase does not use workers, no need for setup 2946 2947 try_inject_alloc_failure(); 2948 op_cleanup(); 2949 } 2950 2951 void ShenandoahHeap::entry_reset() { 2952 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2953 2954 static const char* msg = "Concurrent reset"; 2955 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2956 EventMark em("%s", msg); 2957 2958 ShenandoahWorkerScope scope(workers(), 2959 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2960 "concurrent reset"); 2961 2962 try_inject_alloc_failure(); 2963 op_reset(); 2964 } 2965 2966 void ShenandoahHeap::entry_preclean() { 2967 if (ShenandoahPreclean && process_references()) { 2968 static const char* msg = "Concurrent precleaning"; 2969 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2970 EventMark em("%s", msg); 2971 2972 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2973 2974 ShenandoahWorkerScope scope(workers(), 2975 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2976 "concurrent preclean", 2977 /* check_workers = */ false); 2978 2979 try_inject_alloc_failure(); 2980 op_preclean(); 2981 } 2982 } 2983 2984 void ShenandoahHeap::entry_traversal() { 2985 static const char* msg = conc_traversal_event_message(); 2986 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2987 EventMark em("%s", msg); 2988 2989 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2990 2991 ShenandoahWorkerScope scope(workers(), 2992 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(), 2993 "concurrent traversal"); 2994 2995 try_inject_alloc_failure(); 2996 op_traversal(); 2997 } 2998 2999 void ShenandoahHeap::entry_uncommit(double shrink_before) { 3000 static const char *msg = "Concurrent uncommit"; 3001 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 3002 EventMark em("%s", msg); 3003 3004 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 3005 3006 op_uncommit(shrink_before); 3007 } 3008 3009 void ShenandoahHeap::try_inject_alloc_failure() { 3010 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 3011 _inject_alloc_failure.set(); 3012 os::naked_short_sleep(1); 3013 if (cancelled_gc()) { 3014 log_info(gc)("Allocation failure was successfully injected"); 3015 } 3016 } 3017 } 3018 3019 bool ShenandoahHeap::should_inject_alloc_failure() { 3020 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 3021 } 3022 3023 void ShenandoahHeap::initialize_serviceability() { 3024 _memory_pool = new ShenandoahMemoryPool(this); 3025 _cycle_memory_manager.add_pool(_memory_pool); 3026 _stw_memory_manager.add_pool(_memory_pool); 3027 } 3028 3029 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 3030 GrowableArray<GCMemoryManager*> memory_managers(2); 3031 memory_managers.append(&_cycle_memory_manager); 3032 memory_managers.append(&_stw_memory_manager); 3033 return memory_managers; 3034 } 3035 3036 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 3037 GrowableArray<MemoryPool*> memory_pools(1); 3038 memory_pools.append(_memory_pool); 3039 return memory_pools; 3040 } 3041 3042 MemoryUsage ShenandoahHeap::memory_usage() { 3043 return _memory_pool->get_memory_usage(); 3044 } 3045 3046 void ShenandoahHeap::enter_evacuation() { 3047 _oom_evac_handler.enter_evacuation(); 3048 } 3049 3050 void ShenandoahHeap::leave_evacuation() { 3051 _oom_evac_handler.leave_evacuation(); 3052 } 3053 3054 ShenandoahRegionIterator::ShenandoahRegionIterator() : 3055 _heap(ShenandoahHeap::heap()), 3056 _index(0) {} 3057 3058 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 3059 _heap(heap), 3060 _index(0) {} 3061 3062 void ShenandoahRegionIterator::reset() { 3063 _index = 0; 3064 } 3065 3066 bool ShenandoahRegionIterator::has_next() const { 3067 return _index < _heap->num_regions(); 3068 } 3069 3070 char ShenandoahHeap::gc_state() const { 3071 return _gc_state.raw_value(); 3072 } 3073 3074 void ShenandoahHeap::deduplicate_string(oop str) { 3075 assert(java_lang_String::is_instance(str), "invariant"); 3076 3077 if (ShenandoahStringDedup::is_enabled()) { 3078 ShenandoahStringDedup::deduplicate(str); 3079 } 3080 } 3081 3082 const char* ShenandoahHeap::init_mark_event_message() const { 3083 bool update_refs = has_forwarded_objects(); 3084 bool proc_refs = process_references(); 3085 bool unload_cls = unload_classes(); 3086 3087 if (update_refs && proc_refs && unload_cls) { 3088 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; 3089 } else if (update_refs && proc_refs) { 3090 return "Pause Init Mark (update refs) (process weakrefs)"; 3091 } else if (update_refs && unload_cls) { 3092 return "Pause Init Mark (update refs) (unload classes)"; 3093 } else if (proc_refs && unload_cls) { 3094 return "Pause Init Mark (process weakrefs) (unload classes)"; 3095 } else if (update_refs) { 3096 return "Pause Init Mark (update refs)"; 3097 } else if (proc_refs) { 3098 return "Pause Init Mark (process weakrefs)"; 3099 } else if (unload_cls) { 3100 return "Pause Init Mark (unload classes)"; 3101 } else { 3102 return "Pause Init Mark"; 3103 } 3104 } 3105 3106 const char* ShenandoahHeap::final_mark_event_message() const { 3107 bool update_refs = has_forwarded_objects(); 3108 bool proc_refs = process_references(); 3109 bool unload_cls = unload_classes(); 3110 3111 if (update_refs && proc_refs && unload_cls) { 3112 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; 3113 } else if (update_refs && proc_refs) { 3114 return "Pause Final Mark (update refs) (process weakrefs)"; 3115 } else if (update_refs && unload_cls) { 3116 return "Pause Final Mark (update refs) (unload classes)"; 3117 } else if (proc_refs && unload_cls) { 3118 return "Pause Final Mark (process weakrefs) (unload classes)"; 3119 } else if (update_refs) { 3120 return "Pause Final Mark (update refs)"; 3121 } else if (proc_refs) { 3122 return "Pause Final Mark (process weakrefs)"; 3123 } else if (unload_cls) { 3124 return "Pause Final Mark (unload classes)"; 3125 } else { 3126 return "Pause Final Mark"; 3127 } 3128 } 3129 3130 const char* ShenandoahHeap::conc_mark_event_message() const { 3131 bool update_refs = has_forwarded_objects(); 3132 bool proc_refs = process_references(); 3133 bool unload_cls = unload_classes(); 3134 3135 if (update_refs && proc_refs && unload_cls) { 3136 return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; 3137 } else if (update_refs && proc_refs) { 3138 return "Concurrent marking (update refs) (process weakrefs)"; 3139 } else if (update_refs && unload_cls) { 3140 return "Concurrent marking (update refs) (unload classes)"; 3141 } else if (proc_refs && unload_cls) { 3142 return "Concurrent marking (process weakrefs) (unload classes)"; 3143 } else if (update_refs) { 3144 return "Concurrent marking (update refs)"; 3145 } else if (proc_refs) { 3146 return "Concurrent marking (process weakrefs)"; 3147 } else if (unload_cls) { 3148 return "Concurrent marking (unload classes)"; 3149 } else { 3150 return "Concurrent marking"; 3151 } 3152 } 3153 3154 const char* ShenandoahHeap::init_traversal_event_message() const { 3155 bool proc_refs = process_references(); 3156 bool unload_cls = unload_classes(); 3157 3158 if (proc_refs && unload_cls) { 3159 return "Pause Init Traversal (process weakrefs) (unload classes)"; 3160 } else if (proc_refs) { 3161 return "Pause Init Traversal (process weakrefs)"; 3162 } else if (unload_cls) { 3163 return "Pause Init Traversal (unload classes)"; 3164 } else { 3165 return "Pause Init Traversal"; 3166 } 3167 } 3168 3169 const char* ShenandoahHeap::final_traversal_event_message() const { 3170 bool proc_refs = process_references(); 3171 bool unload_cls = unload_classes(); 3172 3173 if (proc_refs && unload_cls) { 3174 return "Pause Final Traversal (process weakrefs) (unload classes)"; 3175 } else if (proc_refs) { 3176 return "Pause Final Traversal (process weakrefs)"; 3177 } else if (unload_cls) { 3178 return "Pause Final Traversal (unload classes)"; 3179 } else { 3180 return "Pause Final Traversal"; 3181 } 3182 } 3183 3184 const char* ShenandoahHeap::conc_traversal_event_message() const { 3185 bool proc_refs = process_references(); 3186 bool unload_cls = unload_classes(); 3187 3188 if (proc_refs && unload_cls) { 3189 return "Concurrent Traversal (process weakrefs) (unload classes)"; 3190 } else if (proc_refs) { 3191 return "Concurrent Traversal (process weakrefs)"; 3192 } else if (unload_cls) { 3193 return "Concurrent Traversal (unload classes)"; 3194 } else { 3195 return "Concurrent Traversal"; 3196 } 3197 } 3198 3199 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 3200 switch (point) { 3201 case _degenerated_unset: 3202 return "Pause Degenerated GC (<UNSET>)"; 3203 case _degenerated_traversal: 3204 return "Pause Degenerated GC (Traversal)"; 3205 case _degenerated_outside_cycle: 3206 return "Pause Degenerated GC (Outside of Cycle)"; 3207 case _degenerated_mark: 3208 return "Pause Degenerated GC (Mark)"; 3209 case _degenerated_evac: 3210 return "Pause Degenerated GC (Evacuation)"; 3211 case _degenerated_updaterefs: 3212 return "Pause Degenerated GC (Update Refs)"; 3213 default: 3214 ShouldNotReachHere(); 3215 return "ERROR"; 3216 } 3217 } 3218 3219 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 3220 #ifdef ASSERT 3221 assert(_liveness_cache != NULL, "sanity"); 3222 assert(worker_id < _max_workers, "sanity"); 3223 for (uint i = 0; i < num_regions(); i++) { 3224 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 3225 } 3226 #endif 3227 return _liveness_cache[worker_id]; 3228 } 3229 3230 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 3231 assert(worker_id < _max_workers, "sanity"); 3232 assert(_liveness_cache != NULL, "sanity"); 3233 jushort* ld = _liveness_cache[worker_id]; 3234 for (uint i = 0; i < num_regions(); i++) { 3235 ShenandoahHeapRegion* r = get_region(i); 3236 jushort live = ld[i]; 3237 if (live > 0) { 3238 r->increase_live_data_gc_words(live); 3239 ld[i] = 0; 3240 } 3241 } 3242 }