1 /* 2 * Copyright (c) 2013, 2019, Red Hat, Inc. All rights reserved. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "memory/allocation.hpp" 26 #include "memory/universe.hpp" 27 28 #include "gc/shared/gcArguments.hpp" 29 #include "gc/shared/gcTimer.hpp" 30 #include "gc/shared/gcTraceTime.inline.hpp" 31 #include "gc/shared/memAllocator.hpp" 32 #include "gc/shared/parallelCleaning.hpp" 33 #include "gc/shared/plab.hpp" 34 35 #include "gc/shenandoah/shenandoahAllocTracker.hpp" 36 #include "gc/shenandoah/shenandoahBarrierSet.hpp" 37 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 38 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 39 #include "gc/shenandoah/shenandoahCollectorPolicy.hpp" 40 #include "gc/shenandoah/shenandoahConcurrentMark.inline.hpp" 41 #include "gc/shenandoah/shenandoahControlThread.hpp" 42 #include "gc/shenandoah/shenandoahFreeSet.hpp" 43 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 44 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 45 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 46 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 47 #include "gc/shenandoah/shenandoahMarkCompact.hpp" 48 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp" 49 #include "gc/shenandoah/shenandoahMemoryPool.hpp" 50 #include "gc/shenandoah/shenandoahMetrics.hpp" 51 #include "gc/shenandoah/shenandoahMonitoringSupport.hpp" 52 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 53 #include "gc/shenandoah/shenandoahPacer.inline.hpp" 54 #include "gc/shenandoah/shenandoahRootProcessor.inline.hpp" 55 #include "gc/shenandoah/shenandoahStringDedup.hpp" 56 #include "gc/shenandoah/shenandoahTaskqueue.hpp" 57 #include "gc/shenandoah/shenandoahUtils.hpp" 58 #include "gc/shenandoah/shenandoahVerifier.hpp" 59 #include "gc/shenandoah/shenandoahCodeRoots.hpp" 60 #include "gc/shenandoah/shenandoahVMOperations.hpp" 61 #include "gc/shenandoah/shenandoahWorkGroup.hpp" 62 #include "gc/shenandoah/shenandoahWorkerPolicy.hpp" 63 #include "gc/shenandoah/heuristics/shenandoahAdaptiveHeuristics.hpp" 64 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp" 65 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp" 66 #include "gc/shenandoah/heuristics/shenandoahPassiveHeuristics.hpp" 67 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp" 68 #include "gc/shenandoah/heuristics/shenandoahTraversalHeuristics.hpp" 69 #if INCLUDE_JFR 70 #include "gc/shenandoah/shenandoahJfrSupport.hpp" 71 #endif 72 73 #include "memory/metaspace.hpp" 74 #include "oops/compressedOops.inline.hpp" 75 #include "runtime/globals.hpp" 76 #include "runtime/interfaceSupport.inline.hpp" 77 #include "runtime/safepointMechanism.hpp" 78 #include "runtime/vmThread.hpp" 79 #include "services/mallocTracker.hpp" 80 81 #ifdef ASSERT 82 template <class T> 83 void ShenandoahAssertToSpaceClosure::do_oop_work(T* p) { 84 T o = RawAccess<>::oop_load(p); 85 if (! CompressedOops::is_null(o)) { 86 oop obj = CompressedOops::decode_not_null(o); 87 shenandoah_assert_not_forwarded(p, obj); 88 } 89 } 90 91 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_work(p); } 92 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_work(p); } 93 #endif 94 95 class ShenandoahPretouchHeapTask : public AbstractGangTask { 96 private: 97 ShenandoahRegionIterator _regions; 98 const size_t _page_size; 99 public: 100 ShenandoahPretouchHeapTask(size_t page_size) : 101 AbstractGangTask("Shenandoah Pretouch Heap"), 102 _page_size(page_size) {} 103 104 virtual void work(uint worker_id) { 105 ShenandoahHeapRegion* r = _regions.next(); 106 while (r != NULL) { 107 os::pretouch_memory(r->bottom(), r->end(), _page_size); 108 r = _regions.next(); 109 } 110 } 111 }; 112 113 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 114 private: 115 ShenandoahRegionIterator _regions; 116 char* _bitmap_base; 117 const size_t _bitmap_size; 118 const size_t _page_size; 119 public: 120 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 121 AbstractGangTask("Shenandoah Pretouch Bitmap"), 122 _bitmap_base(bitmap_base), 123 _bitmap_size(bitmap_size), 124 _page_size(page_size) {} 125 126 virtual void work(uint worker_id) { 127 ShenandoahHeapRegion* r = _regions.next(); 128 while (r != NULL) { 129 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 130 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 131 assert (end <= _bitmap_size, "end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size); 132 133 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end, _page_size); 134 135 r = _regions.next(); 136 } 137 } 138 }; 139 140 jint ShenandoahHeap::initialize() { 141 initialize_heuristics(); 142 143 // 144 // Figure out heap sizing 145 // 146 147 size_t init_byte_size = InitialHeapSize; 148 size_t min_byte_size = MinHeapSize; 149 size_t max_byte_size = MaxHeapSize; 150 size_t heap_alignment = HeapAlignment; 151 152 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 153 154 if (ShenandoahAlwaysPreTouch) { 155 // Enabled pre-touch means the entire heap is committed right away. 156 init_byte_size = max_byte_size; 157 } 158 159 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 160 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 161 162 _num_regions = ShenandoahHeapRegion::region_count(); 163 164 size_t num_committed_regions = init_byte_size / reg_size_bytes; 165 num_committed_regions = MIN2(num_committed_regions, _num_regions); 166 assert(num_committed_regions <= _num_regions, "sanity"); 167 _initial_size = num_committed_regions * reg_size_bytes; 168 169 size_t num_min_regions = min_byte_size / reg_size_bytes; 170 num_min_regions = MIN2(num_min_regions, _num_regions); 171 assert(num_min_regions <= _num_regions, "sanity"); 172 _minimum_size = num_min_regions * reg_size_bytes; 173 174 _committed = _initial_size; 175 176 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 177 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 178 179 // 180 // Reserve and commit memory for heap 181 // 182 183 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 184 initialize_reserved_region((HeapWord*)heap_rs.base(), (HeapWord*) (heap_rs.base() + heap_rs.size())); 185 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 186 _heap_region_special = heap_rs.special(); 187 188 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 189 "Misaligned heap: " PTR_FORMAT, p2i(base())); 190 191 #if SHENANDOAH_OPTIMIZED_OBJTASK 192 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 193 // Fail if we ever attempt to address more than we can. 194 if ((uintptr_t)heap_rs.end() >= ObjArrayChunkedTask::max_addressable()) { 195 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 196 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 197 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 198 p2i(heap_rs.base()), p2i(heap_rs.end()), ObjArrayChunkedTask::max_addressable()); 199 vm_exit_during_initialization("Fatal Error", buf); 200 } 201 #endif 202 203 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 204 if (!_heap_region_special) { 205 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 206 "Cannot commit heap memory"); 207 } 208 209 // 210 // Reserve and commit memory for bitmap(s) 211 // 212 213 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 214 _bitmap_size = align_up(_bitmap_size, bitmap_page_size); 215 216 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 217 218 guarantee(bitmap_bytes_per_region != 0, 219 "Bitmap bytes per region should not be zero"); 220 guarantee(is_power_of_2(bitmap_bytes_per_region), 221 "Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region); 222 223 if (bitmap_page_size > bitmap_bytes_per_region) { 224 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 225 _bitmap_bytes_per_slice = bitmap_page_size; 226 } else { 227 _bitmap_regions_per_slice = 1; 228 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 229 } 230 231 guarantee(_bitmap_regions_per_slice >= 1, 232 "Should have at least one region per slice: " SIZE_FORMAT, 233 _bitmap_regions_per_slice); 234 235 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 236 "Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 237 _bitmap_bytes_per_slice, bitmap_page_size); 238 239 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 240 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 241 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 242 _bitmap_region_special = bitmap.special(); 243 244 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 245 align_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 246 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 247 if (!_bitmap_region_special) { 248 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 249 "Cannot commit bitmap memory"); 250 } 251 252 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 253 254 if (ShenandoahVerify) { 255 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 256 if (!verify_bitmap.special()) { 257 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 258 "Cannot commit verification bitmap memory"); 259 } 260 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 261 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 262 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 263 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 264 } 265 266 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 267 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 268 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 269 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 270 _aux_bitmap_region_special = aux_bitmap.special(); 271 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 272 273 // 274 // Create regions and region sets 275 // 276 277 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 278 _free_set = new ShenandoahFreeSet(this, _num_regions); 279 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 280 281 { 282 ShenandoahHeapLocker locker(lock()); 283 284 size_t size_words = ShenandoahHeapRegion::region_size_words(); 285 286 for (size_t i = 0; i < _num_regions; i++) { 287 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; 288 bool is_committed = i < num_committed_regions; 289 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); 290 291 _marking_context->initialize_top_at_mark_start(r); 292 _regions[i] = r; 293 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 294 } 295 296 // Initialize to complete 297 _marking_context->mark_complete(); 298 299 _free_set->rebuild(); 300 } 301 302 if (ShenandoahAlwaysPreTouch) { 303 assert(!AlwaysPreTouch, "Should have been overridden"); 304 305 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 306 // before initialize() below zeroes it with initializing thread. For any given region, 307 // we touch the region and the corresponding bitmaps from the same thread. 308 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 309 310 size_t pretouch_heap_page_size = heap_page_size; 311 size_t pretouch_bitmap_page_size = bitmap_page_size; 312 313 #ifdef LINUX 314 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 315 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 316 // them into huge one. Therefore, we need to pretouch with smaller pages. 317 if (UseTransparentHugePages) { 318 pretouch_heap_page_size = (size_t)os::vm_page_size(); 319 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 320 } 321 #endif 322 323 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 324 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 325 326 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 327 _num_regions, pretouch_bitmap_page_size); 328 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 329 _workers->run_task(&bcl); 330 331 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 332 _num_regions, pretouch_heap_page_size); 333 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 334 _workers->run_task(&hcl); 335 } 336 337 // 338 // Initialize the rest of GC subsystems 339 // 340 341 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 342 for (uint worker = 0; worker < _max_workers; worker++) { 343 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 344 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 345 } 346 347 // The call below uses stuff (the SATB* things) that are in G1, but probably 348 // belong into a shared location. 349 ShenandoahBarrierSet::satb_mark_queue_set().initialize(this, 350 SATB_Q_CBL_mon, 351 20 /* G1SATBProcessCompletedThreshold */, 352 60 /* G1SATBBufferEnqueueingThresholdPercent */); 353 354 _monitoring_support = new ShenandoahMonitoringSupport(this); 355 _phase_timings = new ShenandoahPhaseTimings(); 356 ShenandoahStringDedup::initialize(); 357 ShenandoahCodeRoots::initialize(); 358 359 if (ShenandoahAllocationTrace) { 360 _alloc_tracker = new ShenandoahAllocTracker(); 361 } 362 363 if (ShenandoahPacing) { 364 _pacer = new ShenandoahPacer(this); 365 _pacer->setup_for_idle(); 366 } else { 367 _pacer = NULL; 368 } 369 370 _traversal_gc = heuristics()->can_do_traversal_gc() ? 371 new ShenandoahTraversalGC(this, _num_regions) : 372 NULL; 373 374 _control_thread = new ShenandoahControlThread(); 375 376 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 377 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 378 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 379 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 380 ); 381 382 log_info(gc, init)("Safepointing mechanism: %s", 383 SafepointMechanism::uses_thread_local_poll() ? "thread-local poll" : 384 (SafepointMechanism::uses_global_page_poll() ? "global-page poll" : "unknown")); 385 386 return JNI_OK; 387 } 388 389 void ShenandoahHeap::initialize_heuristics() { 390 if (ShenandoahGCHeuristics != NULL) { 391 if (strcmp(ShenandoahGCHeuristics, "aggressive") == 0) { 392 _heuristics = new ShenandoahAggressiveHeuristics(); 393 } else if (strcmp(ShenandoahGCHeuristics, "static") == 0) { 394 _heuristics = new ShenandoahStaticHeuristics(); 395 } else if (strcmp(ShenandoahGCHeuristics, "adaptive") == 0) { 396 _heuristics = new ShenandoahAdaptiveHeuristics(); 397 } else if (strcmp(ShenandoahGCHeuristics, "passive") == 0) { 398 _heuristics = new ShenandoahPassiveHeuristics(); 399 } else if (strcmp(ShenandoahGCHeuristics, "compact") == 0) { 400 _heuristics = new ShenandoahCompactHeuristics(); 401 } else if (strcmp(ShenandoahGCHeuristics, "traversal") == 0) { 402 _heuristics = new ShenandoahTraversalHeuristics(); 403 } else { 404 vm_exit_during_initialization("Unknown -XX:ShenandoahGCHeuristics option"); 405 } 406 407 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 408 vm_exit_during_initialization( 409 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 410 _heuristics->name())); 411 } 412 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 413 vm_exit_during_initialization( 414 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 415 _heuristics->name())); 416 } 417 log_info(gc, init)("Shenandoah heuristics: %s", 418 _heuristics->name()); 419 } else { 420 ShouldNotReachHere(); 421 } 422 423 } 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 "K total, " SIZE_FORMAT "K committed, " SIZE_FORMAT "K used", 531 max_capacity() / K, committed() / K, used() / K); 532 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"K regions", 533 num_regions(), ShenandoahHeapRegion::region_size_bytes() / K); 534 535 st->print("Status: "); 536 if (has_forwarded_objects()) st->print("has forwarded objects, "); 537 if (is_concurrent_mark_in_progress()) st->print("marking, "); 538 if (is_evacuation_in_progress()) st->print("evacuating, "); 539 if (is_update_refs_in_progress()) st->print("updating refs, "); 540 if (is_concurrent_traversal_in_progress()) st->print("traversal, "); 541 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 542 if (is_full_gc_in_progress()) st->print("full gc, "); 543 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 544 545 if (cancelled_gc()) { 546 st->print("cancelled"); 547 } else { 548 st->print("not cancelled"); 549 } 550 st->cr(); 551 552 st->print_cr("Reserved region:"); 553 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 554 p2i(reserved_region().start()), 555 p2i(reserved_region().end())); 556 557 ShenandoahCollectionSet* cset = collection_set(); 558 st->print_cr("Collection set:"); 559 if (cset != NULL) { 560 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 561 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 562 } else { 563 st->print_cr(" (NULL)"); 564 } 565 566 st->cr(); 567 MetaspaceUtils::print_on(st); 568 569 if (Verbose) { 570 print_heap_regions_on(st); 571 } 572 } 573 574 class ShenandoahInitWorkerGCLABClosure : public ThreadClosure { 575 public: 576 void do_thread(Thread* thread) { 577 assert(thread != NULL, "Sanity"); 578 assert(thread->is_Worker_thread(), "Only worker thread expected"); 579 ShenandoahThreadLocalData::initialize_gclab(thread); 580 } 581 }; 582 583 void ShenandoahHeap::post_initialize() { 584 CollectedHeap::post_initialize(); 585 MutexLocker ml(Threads_lock); 586 587 ShenandoahInitWorkerGCLABClosure init_gclabs; 588 _workers->threads_do(&init_gclabs); 589 590 // gclab can not be initialized early during VM startup, as it can not determinate its max_size. 591 // Now, we will let WorkGang to initialize gclab when new worker is created. 592 _workers->set_initialize_gclab(); 593 594 _scm->initialize(_max_workers); 595 _full_gc->initialize(_gc_timer); 596 597 ref_processing_init(); 598 599 _heuristics->initialize(); 600 601 JFR_ONLY(ShenandoahJFRSupport::register_jfr_type_serializers()); 602 } 603 604 size_t ShenandoahHeap::used() const { 605 return OrderAccess::load_acquire(&_used); 606 } 607 608 size_t ShenandoahHeap::committed() const { 609 OrderAccess::acquire(); 610 return _committed; 611 } 612 613 void ShenandoahHeap::increase_committed(size_t bytes) { 614 assert_heaplock_or_safepoint(); 615 _committed += bytes; 616 } 617 618 void ShenandoahHeap::decrease_committed(size_t bytes) { 619 assert_heaplock_or_safepoint(); 620 _committed -= bytes; 621 } 622 623 void ShenandoahHeap::increase_used(size_t bytes) { 624 Atomic::add(bytes, &_used); 625 } 626 627 void ShenandoahHeap::set_used(size_t bytes) { 628 OrderAccess::release_store_fence(&_used, bytes); 629 } 630 631 void ShenandoahHeap::decrease_used(size_t bytes) { 632 assert(used() >= bytes, "never decrease heap size by more than we've left"); 633 Atomic::sub(bytes, &_used); 634 } 635 636 void ShenandoahHeap::increase_allocated(size_t bytes) { 637 Atomic::add(bytes, &_bytes_allocated_since_gc_start); 638 } 639 640 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 641 size_t bytes = words * HeapWordSize; 642 if (!waste) { 643 increase_used(bytes); 644 } 645 increase_allocated(bytes); 646 if (ShenandoahPacing) { 647 control_thread()->pacing_notify_alloc(words); 648 if (waste) { 649 pacer()->claim_for_alloc(words, true); 650 } 651 } 652 } 653 654 size_t ShenandoahHeap::capacity() const { 655 return committed(); 656 } 657 658 size_t ShenandoahHeap::max_capacity() const { 659 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 660 } 661 662 size_t ShenandoahHeap::min_capacity() const { 663 return _minimum_size; 664 } 665 666 size_t ShenandoahHeap::initial_capacity() const { 667 return _initial_size; 668 } 669 670 bool ShenandoahHeap::is_in(const void* p) const { 671 HeapWord* heap_base = (HeapWord*) base(); 672 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 673 return p >= heap_base && p < last_region_end; 674 } 675 676 void ShenandoahHeap::op_uncommit(double shrink_before) { 677 assert (ShenandoahUncommit, "should be enabled"); 678 679 // Application allocates from the beginning of the heap, and GC allocates at 680 // the end of it. It is more efficient to uncommit from the end, so that applications 681 // could enjoy the near committed regions. GC allocations are much less frequent, 682 // and therefore can accept the committing costs. 683 684 size_t count = 0; 685 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 686 ShenandoahHeapRegion* r = get_region(i - 1); 687 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 688 ShenandoahHeapLocker locker(lock()); 689 if (r->is_empty_committed()) { 690 // Do not uncommit below minimal capacity 691 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 692 break; 693 } 694 695 r->make_uncommitted(); 696 count++; 697 } 698 } 699 SpinPause(); // allow allocators to take the lock 700 } 701 702 if (count > 0) { 703 control_thread()->notify_heap_changed(); 704 } 705 } 706 707 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 708 // New object should fit the GCLAB size 709 size_t min_size = MAX2(size, PLAB::min_size()); 710 711 // Figure out size of new GCLAB, looking back at heuristics. Expand aggressively. 712 size_t new_size = ShenandoahThreadLocalData::gclab_size(thread) * 2; 713 new_size = MIN2(new_size, PLAB::max_size()); 714 new_size = MAX2(new_size, PLAB::min_size()); 715 716 // Record new heuristic value even if we take any shortcut. This captures 717 // the case when moderately-sized objects always take a shortcut. At some point, 718 // heuristics should catch up with them. 719 ShenandoahThreadLocalData::set_gclab_size(thread, new_size); 720 721 if (new_size < size) { 722 // New size still does not fit the object. Fall back to shared allocation. 723 // This avoids retiring perfectly good GCLABs, when we encounter a large object. 724 return NULL; 725 } 726 727 // Retire current GCLAB, and allocate a new one. 728 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 729 gclab->retire(); 730 731 size_t actual_size = 0; 732 HeapWord* gclab_buf = allocate_new_gclab(min_size, new_size, &actual_size); 733 if (gclab_buf == NULL) { 734 return NULL; 735 } 736 737 assert (size <= actual_size, "allocation should fit"); 738 739 if (ZeroTLAB) { 740 // ..and clear it. 741 Copy::zero_to_words(gclab_buf, actual_size); 742 } else { 743 // ...and zap just allocated object. 744 #ifdef ASSERT 745 // Skip mangling the space corresponding to the object header to 746 // ensure that the returned space is not considered parsable by 747 // any concurrent GC thread. 748 size_t hdr_size = oopDesc::header_size(); 749 Copy::fill_to_words(gclab_buf + hdr_size, actual_size - hdr_size, badHeapWordVal); 750 #endif // ASSERT 751 } 752 gclab->set_buf(gclab_buf, actual_size); 753 return gclab->allocate(size); 754 } 755 756 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t min_size, 757 size_t requested_size, 758 size_t* actual_size) { 759 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(min_size, requested_size); 760 HeapWord* res = allocate_memory(req); 761 if (res != NULL) { 762 *actual_size = req.actual_size(); 763 } else { 764 *actual_size = 0; 765 } 766 return res; 767 } 768 769 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 770 size_t word_size, 771 size_t* actual_size) { 772 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 773 HeapWord* res = allocate_memory(req); 774 if (res != NULL) { 775 *actual_size = req.actual_size(); 776 } else { 777 *actual_size = 0; 778 } 779 return res; 780 } 781 782 ShenandoahHeap* ShenandoahHeap::heap() { 783 CollectedHeap* heap = Universe::heap(); 784 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); 785 assert(heap->kind() == CollectedHeap::Shenandoah, "not a shenandoah heap"); 786 return (ShenandoahHeap*) heap; 787 } 788 789 ShenandoahHeap* ShenandoahHeap::heap_no_check() { 790 CollectedHeap* heap = Universe::heap(); 791 return (ShenandoahHeap*) heap; 792 } 793 794 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 795 ShenandoahAllocTrace trace_alloc(req.size(), req.type()); 796 797 intptr_t pacer_epoch = 0; 798 bool in_new_region = false; 799 HeapWord* result = NULL; 800 801 if (req.is_mutator_alloc()) { 802 if (ShenandoahPacing) { 803 pacer()->pace_for_alloc(req.size()); 804 pacer_epoch = pacer()->epoch(); 805 } 806 807 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 808 result = allocate_memory_under_lock(req, in_new_region); 809 } 810 811 // Allocation failed, block until control thread reacted, then retry allocation. 812 // 813 // It might happen that one of the threads requesting allocation would unblock 814 // way later after GC happened, only to fail the second allocation, because 815 // other threads have already depleted the free storage. In this case, a better 816 // strategy is to try again, as long as GC makes progress. 817 // 818 // Then, we need to make sure the allocation was retried after at least one 819 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 820 821 size_t tries = 0; 822 823 while (result == NULL && _progress_last_gc.is_set()) { 824 tries++; 825 control_thread()->handle_alloc_failure(req.size()); 826 result = allocate_memory_under_lock(req, in_new_region); 827 } 828 829 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 830 tries++; 831 control_thread()->handle_alloc_failure(req.size()); 832 result = allocate_memory_under_lock(req, in_new_region); 833 } 834 835 } else { 836 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 837 result = allocate_memory_under_lock(req, in_new_region); 838 // Do not call handle_alloc_failure() here, because we cannot block. 839 // The allocation failure would be handled by the LRB slowpath with handle_alloc_failure_evac(). 840 } 841 842 if (in_new_region) { 843 control_thread()->notify_heap_changed(); 844 } 845 846 if (result != NULL) { 847 size_t requested = req.size(); 848 size_t actual = req.actual_size(); 849 850 assert (req.is_lab_alloc() || (requested == actual), 851 "Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 852 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual); 853 854 if (req.is_mutator_alloc()) { 855 notify_mutator_alloc_words(actual, false); 856 857 // If we requested more than we were granted, give the rest back to pacer. 858 // This only matters if we are in the same pacing epoch: do not try to unpace 859 // over the budget for the other phase. 860 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 861 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 862 } 863 } else { 864 increase_used(actual*HeapWordSize); 865 } 866 } 867 868 return result; 869 } 870 871 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 872 ShenandoahHeapLocker locker(lock()); 873 return _free_set->allocate(req, in_new_region); 874 } 875 876 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 877 bool* gc_overhead_limit_was_exceeded) { 878 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 879 return allocate_memory(req); 880 } 881 882 MetaWord* ShenandoahHeap::satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 883 size_t size, 884 Metaspace::MetadataType mdtype) { 885 MetaWord* result; 886 887 // Inform metaspace OOM to GC heuristics if class unloading is possible. 888 if (heuristics()->can_unload_classes()) { 889 ShenandoahHeuristics* h = heuristics(); 890 h->record_metaspace_oom(); 891 } 892 893 // Expand and retry allocation 894 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 895 if (result != NULL) { 896 return result; 897 } 898 899 // Start full GC 900 collect(GCCause::_metadata_GC_clear_soft_refs); 901 902 // Retry allocation 903 result = loader_data->metaspace_non_null()->allocate(size, mdtype); 904 if (result != NULL) { 905 return result; 906 } 907 908 // Expand and retry allocation 909 result = loader_data->metaspace_non_null()->expand_and_allocate(size, mdtype); 910 if (result != NULL) { 911 return result; 912 } 913 914 // Out of memory 915 return NULL; 916 } 917 918 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 919 private: 920 ShenandoahHeap* const _heap; 921 Thread* const _thread; 922 public: 923 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 924 _heap(heap), _thread(Thread::current()) {} 925 926 void do_object(oop p) { 927 shenandoah_assert_marked(NULL, p); 928 if (!p->is_forwarded()) { 929 _heap->evacuate_object(p, _thread); 930 } 931 } 932 }; 933 934 class ShenandoahEvacuationTask : public AbstractGangTask { 935 private: 936 ShenandoahHeap* const _sh; 937 ShenandoahCollectionSet* const _cs; 938 bool _concurrent; 939 public: 940 ShenandoahEvacuationTask(ShenandoahHeap* sh, 941 ShenandoahCollectionSet* cs, 942 bool concurrent) : 943 AbstractGangTask("Parallel Evacuation Task"), 944 _sh(sh), 945 _cs(cs), 946 _concurrent(concurrent) 947 {} 948 949 void work(uint worker_id) { 950 if (_concurrent) { 951 ShenandoahConcurrentWorkerSession worker_session(worker_id); 952 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 953 ShenandoahEvacOOMScope oom_evac_scope; 954 do_work(); 955 } else { 956 ShenandoahParallelWorkerSession worker_session(worker_id); 957 ShenandoahEvacOOMScope oom_evac_scope; 958 do_work(); 959 } 960 } 961 962 private: 963 void do_work() { 964 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 965 ShenandoahHeapRegion* r; 966 while ((r =_cs->claim_next()) != NULL) { 967 assert(r->has_live(), "all-garbage regions are reclaimed early"); 968 _sh->marked_object_iterate(r, &cl); 969 970 if (ShenandoahPacing) { 971 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 972 } 973 974 if (_sh->check_cancelled_gc_and_yield(_concurrent)) { 975 break; 976 } 977 } 978 } 979 }; 980 981 void ShenandoahHeap::trash_cset_regions() { 982 ShenandoahHeapLocker locker(lock()); 983 984 ShenandoahCollectionSet* set = collection_set(); 985 ShenandoahHeapRegion* r; 986 set->clear_current_index(); 987 while ((r = set->next()) != NULL) { 988 r->make_trash(); 989 } 990 collection_set()->clear(); 991 } 992 993 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 994 st->print_cr("Heap Regions:"); 995 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 996 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 997 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); 998 st->print_cr("SN=alloc sequence numbers (first mutator, last mutator, first gc, last gc)"); 999 1000 for (size_t i = 0; i < num_regions(); i++) { 1001 get_region(i)->print_on(st); 1002 } 1003 } 1004 1005 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 1006 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 1007 1008 oop humongous_obj = oop(start->bottom()); 1009 size_t size = humongous_obj->size(); 1010 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 1011 size_t index = start->region_number() + required_regions - 1; 1012 1013 assert(!start->has_live(), "liveness must be zero"); 1014 1015 for(size_t i = 0; i < required_regions; i++) { 1016 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 1017 // as it expects that every region belongs to a humongous region starting with a humongous start region. 1018 ShenandoahHeapRegion* region = get_region(index --); 1019 1020 assert(region->is_humongous(), "expect correct humongous start or continuation"); 1021 assert(!region->is_cset(), "Humongous region should not be in collection set"); 1022 1023 region->make_trash_immediate(); 1024 } 1025 } 1026 1027 class ShenandoahRetireGCLABClosure : public ThreadClosure { 1028 public: 1029 void do_thread(Thread* thread) { 1030 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1031 assert(gclab != NULL, "GCLAB should be initialized for %s", thread->name()); 1032 gclab->retire(); 1033 } 1034 }; 1035 1036 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 1037 if (UseTLAB) { 1038 CollectedHeap::ensure_parsability(retire_tlabs); 1039 } 1040 ShenandoahRetireGCLABClosure cl; 1041 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1042 cl.do_thread(t); 1043 } 1044 workers()->threads_do(&cl); 1045 } 1046 1047 void ShenandoahHeap::resize_tlabs() { 1048 CollectedHeap::resize_all_tlabs(); 1049 } 1050 1051 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 1052 private: 1053 ShenandoahRootEvacuator* _rp; 1054 1055 public: 1056 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 1057 AbstractGangTask("Shenandoah evacuate and update roots"), 1058 _rp(rp) {} 1059 1060 void work(uint worker_id) { 1061 ShenandoahParallelWorkerSession worker_session(worker_id); 1062 ShenandoahEvacOOMScope oom_evac_scope; 1063 ShenandoahEvacuateUpdateRootsClosure cl; 1064 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 1065 _rp->roots_do(worker_id, &cl); 1066 } 1067 }; 1068 1069 void ShenandoahHeap::evacuate_and_update_roots() { 1070 #if COMPILER2_OR_JVMCI 1071 DerivedPointerTable::clear(); 1072 #endif 1073 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1074 1075 { 1076 ShenandoahRootEvacuator rp(workers()->active_workers(), ShenandoahPhaseTimings::init_evac); 1077 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 1078 workers()->run_task(&roots_task); 1079 } 1080 1081 #if COMPILER2_OR_JVMCI 1082 DerivedPointerTable::update_pointers(); 1083 #endif 1084 } 1085 1086 // Returns size in bytes 1087 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1088 if (ShenandoahElasticTLAB) { 1089 // With Elastic TLABs, return the max allowed size, and let the allocation path 1090 // figure out the safe size for current allocation. 1091 return ShenandoahHeapRegion::max_tlab_size_bytes(); 1092 } else { 1093 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1094 } 1095 } 1096 1097 size_t ShenandoahHeap::max_tlab_size() const { 1098 // Returns size in words 1099 return ShenandoahHeapRegion::max_tlab_size_words(); 1100 } 1101 1102 class ShenandoahRetireAndResetGCLABClosure : public ThreadClosure { 1103 public: 1104 void do_thread(Thread* thread) { 1105 PLAB* gclab = ShenandoahThreadLocalData::gclab(thread); 1106 gclab->retire(); 1107 if (ShenandoahThreadLocalData::gclab_size(thread) > 0) { 1108 ShenandoahThreadLocalData::set_gclab_size(thread, 0); 1109 } 1110 } 1111 }; 1112 1113 void ShenandoahHeap::retire_and_reset_gclabs() { 1114 ShenandoahRetireAndResetGCLABClosure cl; 1115 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1116 cl.do_thread(t); 1117 } 1118 workers()->threads_do(&cl); 1119 } 1120 1121 void ShenandoahHeap::collect(GCCause::Cause cause) { 1122 control_thread()->request_gc(cause); 1123 } 1124 1125 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1126 //assert(false, "Shouldn't need to do full collections"); 1127 } 1128 1129 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1130 Space* sp = heap_region_containing(addr); 1131 if (sp != NULL) { 1132 return sp->block_start(addr); 1133 } 1134 return NULL; 1135 } 1136 1137 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1138 Space* sp = heap_region_containing(addr); 1139 return sp->block_is_obj(addr); 1140 } 1141 1142 jlong ShenandoahHeap::millis_since_last_gc() { 1143 double v = heuristics()->time_since_last_gc() * 1000; 1144 assert(0 <= v && v <= max_jlong, "value should fit: %f", v); 1145 return (jlong)v; 1146 } 1147 1148 void ShenandoahHeap::prepare_for_verify() { 1149 if (SafepointSynchronize::is_at_safepoint() || ! UseTLAB) { 1150 make_parsable(false); 1151 } 1152 } 1153 1154 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1155 workers()->print_worker_threads_on(st); 1156 if (ShenandoahStringDedup::is_enabled()) { 1157 ShenandoahStringDedup::print_worker_threads_on(st); 1158 } 1159 } 1160 1161 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1162 workers()->threads_do(tcl); 1163 if (_safepoint_workers != NULL) { 1164 _safepoint_workers->threads_do(tcl); 1165 } 1166 if (ShenandoahStringDedup::is_enabled()) { 1167 ShenandoahStringDedup::threads_do(tcl); 1168 } 1169 } 1170 1171 void ShenandoahHeap::print_tracing_info() const { 1172 LogTarget(Info, gc, stats) lt; 1173 if (lt.is_enabled()) { 1174 ResourceMark rm; 1175 LogStream ls(lt); 1176 1177 phase_timings()->print_on(&ls); 1178 1179 ls.cr(); 1180 ls.cr(); 1181 1182 shenandoah_policy()->print_gc_stats(&ls); 1183 1184 ls.cr(); 1185 ls.cr(); 1186 1187 if (ShenandoahPacing) { 1188 pacer()->print_on(&ls); 1189 } 1190 1191 ls.cr(); 1192 ls.cr(); 1193 1194 if (ShenandoahAllocationTrace) { 1195 assert(alloc_tracker() != NULL, "Must be"); 1196 alloc_tracker()->print_on(&ls); 1197 } else { 1198 ls.print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); 1199 } 1200 } 1201 } 1202 1203 void ShenandoahHeap::verify(VerifyOption vo) { 1204 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 1205 if (ShenandoahVerify) { 1206 verifier()->verify_generic(vo); 1207 } else { 1208 // TODO: Consider allocating verification bitmaps on demand, 1209 // and turn this on unconditionally. 1210 } 1211 } 1212 } 1213 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1214 return _free_set->capacity(); 1215 } 1216 1217 class ObjectIterateScanRootClosure : public BasicOopIterateClosure { 1218 private: 1219 MarkBitMap* _bitmap; 1220 Stack<oop,mtGC>* _oop_stack; 1221 1222 template <class T> 1223 void do_oop_work(T* p) { 1224 T o = RawAccess<>::oop_load(p); 1225 if (!CompressedOops::is_null(o)) { 1226 oop obj = CompressedOops::decode_not_null(o); 1227 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 1228 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1229 if (!_bitmap->is_marked((HeapWord*) obj)) { 1230 _bitmap->mark((HeapWord*) obj); 1231 _oop_stack->push(obj); 1232 } 1233 } 1234 } 1235 public: 1236 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1237 _bitmap(bitmap), _oop_stack(oop_stack) {} 1238 void do_oop(oop* p) { do_oop_work(p); } 1239 void do_oop(narrowOop* p) { do_oop_work(p); } 1240 }; 1241 1242 /* 1243 * This is public API, used in preparation of object_iterate(). 1244 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1245 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1246 * control, we call SH::make_tlabs_parsable(). 1247 */ 1248 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1249 // No-op. 1250 } 1251 1252 /* 1253 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1254 * 1255 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1256 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1257 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1258 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1259 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1260 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1261 * wiped the bitmap in preparation for next marking). 1262 * 1263 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1264 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1265 * is allowed to report dead objects, but is not required to do so. 1266 */ 1267 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1268 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1269 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1270 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1271 return; 1272 } 1273 1274 // Reset bitmap 1275 _aux_bit_map.clear(); 1276 1277 Stack<oop,mtGC> oop_stack; 1278 1279 // First, we process all GC roots. This populates the work stack with initial objects. 1280 ShenandoahAllRootScanner rp(1, ShenandoahPhaseTimings::_num_phases); 1281 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1282 rp.roots_do_unchecked(&oops); 1283 1284 // Work through the oop stack to traverse heap. 1285 while (! oop_stack.is_empty()) { 1286 oop obj = oop_stack.pop(); 1287 assert(oopDesc::is_oop(obj), "must be a valid oop"); 1288 cl->do_object(obj); 1289 obj->oop_iterate(&oops); 1290 } 1291 1292 assert(oop_stack.is_empty(), "should be empty"); 1293 1294 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1295 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1296 } 1297 } 1298 1299 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) { 1300 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1301 object_iterate(cl); 1302 } 1303 1304 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1305 for (size_t i = 0; i < num_regions(); i++) { 1306 ShenandoahHeapRegion* current = get_region(i); 1307 blk->heap_region_do(current); 1308 } 1309 } 1310 1311 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1312 private: 1313 ShenandoahHeap* const _heap; 1314 ShenandoahHeapRegionClosure* const _blk; 1315 1316 DEFINE_PAD_MINUS_SIZE(0, DEFAULT_CACHE_LINE_SIZE, sizeof(volatile size_t)); 1317 volatile size_t _index; 1318 DEFINE_PAD_MINUS_SIZE(1, DEFAULT_CACHE_LINE_SIZE, 0); 1319 1320 public: 1321 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1322 AbstractGangTask("Parallel Region Task"), 1323 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1324 1325 void work(uint worker_id) { 1326 size_t stride = ShenandoahParallelRegionStride; 1327 1328 size_t max = _heap->num_regions(); 1329 while (_index < max) { 1330 size_t cur = Atomic::add(stride, &_index) - stride; 1331 size_t start = cur; 1332 size_t end = MIN2(cur + stride, max); 1333 if (start >= max) break; 1334 1335 for (size_t i = cur; i < end; i++) { 1336 ShenandoahHeapRegion* current = _heap->get_region(i); 1337 _blk->heap_region_do(current); 1338 } 1339 } 1340 } 1341 }; 1342 1343 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1344 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1345 if (num_regions() > ShenandoahParallelRegionStride) { 1346 ShenandoahParallelHeapRegionTask task(blk); 1347 workers()->run_task(&task); 1348 } else { 1349 heap_region_iterate(blk); 1350 } 1351 } 1352 1353 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { 1354 private: 1355 ShenandoahMarkingContext* const _ctx; 1356 public: 1357 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1358 1359 void heap_region_do(ShenandoahHeapRegion* r) { 1360 if (r->is_active()) { 1361 r->clear_live_data(); 1362 _ctx->capture_top_at_mark_start(r); 1363 } else { 1364 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1365 assert(_ctx->top_at_mark_start(r) == r->top(), 1366 "Region " SIZE_FORMAT " should already have correct TAMS", r->region_number()); 1367 } 1368 } 1369 1370 bool is_thread_safe() { return true; } 1371 }; 1372 1373 void ShenandoahHeap::op_init_mark() { 1374 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1375 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1376 1377 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1378 assert(!marking_context()->is_complete(), "should not be complete"); 1379 1380 if (ShenandoahVerify) { 1381 verifier()->verify_before_concmark(); 1382 } 1383 1384 if (VerifyBeforeGC) { 1385 Universe::verify(); 1386 } 1387 1388 set_concurrent_mark_in_progress(true); 1389 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1390 { 1391 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1392 make_parsable(true); 1393 } 1394 1395 { 1396 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); 1397 ShenandoahClearLivenessClosure clc; 1398 parallel_heap_region_iterate(&clc); 1399 } 1400 1401 // Make above changes visible to worker threads 1402 OrderAccess::fence(); 1403 1404 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1405 1406 if (UseTLAB) { 1407 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1408 resize_tlabs(); 1409 } 1410 1411 if (ShenandoahPacing) { 1412 pacer()->setup_for_mark(); 1413 } 1414 } 1415 1416 void ShenandoahHeap::op_mark() { 1417 concurrent_mark()->mark_from_roots(); 1418 } 1419 1420 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { 1421 private: 1422 ShenandoahMarkingContext* const _ctx; 1423 public: 1424 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} 1425 1426 void heap_region_do(ShenandoahHeapRegion* r) { 1427 if (r->is_active()) { 1428 HeapWord *tams = _ctx->top_at_mark_start(r); 1429 HeapWord *top = r->top(); 1430 if (top > tams) { 1431 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1432 } 1433 } else { 1434 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->region_number()); 1435 assert(_ctx->top_at_mark_start(r) == r->top(), 1436 "Region " SIZE_FORMAT " should have correct TAMS", r->region_number()); 1437 } 1438 } 1439 1440 bool is_thread_safe() { return true; } 1441 }; 1442 1443 void ShenandoahHeap::op_final_mark() { 1444 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1445 1446 // It is critical that we 1447 // evacuate roots right after finishing marking, so that we don't 1448 // get unmarked objects in the roots. 1449 1450 if (!cancelled_gc()) { 1451 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); 1452 1453 if (has_forwarded_objects()) { 1454 // Degen may be caused by failed evacuation of roots 1455 if (is_degenerated_gc_in_progress()) { 1456 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 1457 } else { 1458 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::update_roots); 1459 } 1460 } 1461 1462 if (ShenandoahVerify) { 1463 verifier()->verify_roots_no_forwarded(); 1464 } 1465 1466 stop_concurrent_marking(); 1467 1468 { 1469 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); 1470 1471 // All allocations past TAMS are implicitly live, adjust the region data. 1472 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1473 ShenandoahCompleteLivenessClosure cl; 1474 parallel_heap_region_iterate(&cl); 1475 } 1476 1477 { 1478 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac); 1479 1480 make_parsable(true); 1481 1482 trash_cset_regions(); 1483 1484 { 1485 ShenandoahHeapLocker locker(lock()); 1486 _collection_set->clear(); 1487 _free_set->clear(); 1488 1489 heuristics()->choose_collection_set(_collection_set); 1490 1491 _free_set->rebuild(); 1492 } 1493 } 1494 1495 // If collection set has candidates, start evacuation. 1496 // Otherwise, bypass the rest of the cycle. 1497 if (!collection_set()->is_empty()) { 1498 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1499 1500 if (ShenandoahVerify) { 1501 verifier()->verify_before_evacuation(); 1502 } 1503 1504 set_evacuation_in_progress(true); 1505 // From here on, we need to update references. 1506 set_has_forwarded_objects(true); 1507 1508 evacuate_and_update_roots(); 1509 1510 if (ShenandoahPacing) { 1511 pacer()->setup_for_evac(); 1512 } 1513 1514 if (ShenandoahVerify) { 1515 verifier()->verify_roots_no_forwarded(); 1516 verifier()->verify_during_evacuation(); 1517 } 1518 } else { 1519 if (ShenandoahVerify) { 1520 verifier()->verify_after_concmark(); 1521 } 1522 1523 if (VerifyAfterGC) { 1524 Universe::verify(); 1525 } 1526 } 1527 1528 } else { 1529 concurrent_mark()->cancel(); 1530 stop_concurrent_marking(); 1531 1532 if (process_references()) { 1533 // Abandon reference processing right away: pre-cleaning must have failed. 1534 ReferenceProcessor *rp = ref_processor(); 1535 rp->disable_discovery(); 1536 rp->abandon_partial_discovery(); 1537 rp->verify_no_references_recorded(); 1538 } 1539 } 1540 } 1541 1542 void ShenandoahHeap::op_final_evac() { 1543 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1544 1545 set_evacuation_in_progress(false); 1546 1547 retire_and_reset_gclabs(); 1548 1549 if (ShenandoahVerify) { 1550 verifier()->verify_after_evacuation(); 1551 } 1552 1553 if (VerifyAfterGC) { 1554 Universe::verify(); 1555 } 1556 } 1557 1558 void ShenandoahHeap::op_conc_evac() { 1559 ShenandoahEvacuationTask task(this, _collection_set, true); 1560 workers()->run_task(&task); 1561 } 1562 1563 void ShenandoahHeap::op_stw_evac() { 1564 ShenandoahEvacuationTask task(this, _collection_set, false); 1565 workers()->run_task(&task); 1566 } 1567 1568 void ShenandoahHeap::op_updaterefs() { 1569 update_heap_references(true); 1570 } 1571 1572 void ShenandoahHeap::op_cleanup() { 1573 free_set()->recycle_trash(); 1574 } 1575 1576 void ShenandoahHeap::op_reset() { 1577 reset_mark_bitmap(); 1578 } 1579 1580 void ShenandoahHeap::op_preclean() { 1581 concurrent_mark()->preclean_weak_refs(); 1582 } 1583 1584 void ShenandoahHeap::op_init_traversal() { 1585 traversal_gc()->init_traversal_collection(); 1586 } 1587 1588 void ShenandoahHeap::op_traversal() { 1589 traversal_gc()->concurrent_traversal_collection(); 1590 } 1591 1592 void ShenandoahHeap::op_final_traversal() { 1593 traversal_gc()->final_traversal_collection(); 1594 } 1595 1596 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1597 ShenandoahMetricsSnapshot metrics; 1598 metrics.snap_before(); 1599 1600 full_gc()->do_it(cause); 1601 if (UseTLAB) { 1602 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_resize_tlabs); 1603 resize_all_tlabs(); 1604 } 1605 1606 metrics.snap_after(); 1607 1608 if (metrics.is_good_progress()) { 1609 _progress_last_gc.set(); 1610 } else { 1611 // Nothing to do. Tell the allocation path that we have failed to make 1612 // progress, and it can finally fail. 1613 _progress_last_gc.unset(); 1614 } 1615 } 1616 1617 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1618 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1619 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1620 // some phase, we have to upgrade the Degenerate GC to Full GC. 1621 1622 clear_cancelled_gc(); 1623 1624 ShenandoahMetricsSnapshot metrics; 1625 metrics.snap_before(); 1626 1627 switch (point) { 1628 case _degenerated_traversal: 1629 { 1630 // Drop the collection set. Note: this leaves some already forwarded objects 1631 // behind, which may be problematic, see comments for ShenandoahEvacAssist 1632 // workarounds in ShenandoahTraversalHeuristics. 1633 1634 ShenandoahHeapLocker locker(lock()); 1635 collection_set()->clear_current_index(); 1636 for (size_t i = 0; i < collection_set()->count(); i++) { 1637 ShenandoahHeapRegion* r = collection_set()->next(); 1638 r->make_regular_bypass(); 1639 } 1640 collection_set()->clear(); 1641 } 1642 op_final_traversal(); 1643 op_cleanup(); 1644 return; 1645 1646 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1647 // but enters it at different points, depending on which concurrent phase had 1648 // degenerated. 1649 1650 case _degenerated_outside_cycle: 1651 // We have degenerated from outside the cycle, which means something is bad with 1652 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1653 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1654 // we can do the most aggressive degen cycle, which includes processing references and 1655 // class unloading, unless those features are explicitly disabled. 1656 // 1657 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1658 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1659 set_process_references(heuristics()->can_process_references()); 1660 set_unload_classes(heuristics()->can_unload_classes()); 1661 1662 if (heuristics()->can_do_traversal_gc()) { 1663 // Not possible to degenerate from here, upgrade to Full GC right away. 1664 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1665 op_degenerated_fail(); 1666 return; 1667 } 1668 1669 op_reset(); 1670 1671 op_init_mark(); 1672 if (cancelled_gc()) { 1673 op_degenerated_fail(); 1674 return; 1675 } 1676 1677 case _degenerated_mark: 1678 op_final_mark(); 1679 if (cancelled_gc()) { 1680 op_degenerated_fail(); 1681 return; 1682 } 1683 1684 op_cleanup(); 1685 1686 case _degenerated_evac: 1687 // If heuristics thinks we should do the cycle, this flag would be set, 1688 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1689 if (is_evacuation_in_progress()) { 1690 1691 // Degeneration under oom-evac protocol might have left some objects in 1692 // collection set un-evacuated. Restart evacuation from the beginning to 1693 // capture all objects. For all the objects that are already evacuated, 1694 // it would be a simple check, which is supposed to be fast. This is also 1695 // safe to do even without degeneration, as CSet iterator is at beginning 1696 // in preparation for evacuation anyway. 1697 collection_set()->clear_current_index(); 1698 1699 op_stw_evac(); 1700 if (cancelled_gc()) { 1701 op_degenerated_fail(); 1702 return; 1703 } 1704 } 1705 1706 // If heuristics thinks we should do the cycle, this flag would be set, 1707 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1708 if (has_forwarded_objects()) { 1709 op_init_updaterefs(); 1710 if (cancelled_gc()) { 1711 op_degenerated_fail(); 1712 return; 1713 } 1714 } 1715 1716 case _degenerated_updaterefs: 1717 if (has_forwarded_objects()) { 1718 op_final_updaterefs(); 1719 if (cancelled_gc()) { 1720 op_degenerated_fail(); 1721 return; 1722 } 1723 } 1724 1725 op_cleanup(); 1726 break; 1727 1728 default: 1729 ShouldNotReachHere(); 1730 } 1731 1732 if (ShenandoahVerify) { 1733 verifier()->verify_after_degenerated(); 1734 } 1735 1736 if (VerifyAfterGC) { 1737 Universe::verify(); 1738 } 1739 1740 metrics.snap_after(); 1741 1742 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 1743 // because that probably means the heap is overloaded and/or fragmented. 1744 if (!metrics.is_good_progress()) { 1745 _progress_last_gc.unset(); 1746 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1747 op_degenerated_futile(); 1748 } else { 1749 _progress_last_gc.set(); 1750 } 1751 } 1752 1753 void ShenandoahHeap::op_degenerated_fail() { 1754 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 1755 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1756 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1757 } 1758 1759 void ShenandoahHeap::op_degenerated_futile() { 1760 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1761 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1762 } 1763 1764 void ShenandoahHeap::stop_concurrent_marking() { 1765 assert(is_concurrent_mark_in_progress(), "How else could we get here?"); 1766 set_concurrent_mark_in_progress(false); 1767 if (!cancelled_gc()) { 1768 // If we needed to update refs, and concurrent marking has been cancelled, 1769 // we need to finish updating references. 1770 set_has_forwarded_objects(false); 1771 mark_complete_marking_context(); 1772 } 1773 } 1774 1775 void ShenandoahHeap::force_satb_flush_all_threads() { 1776 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) { 1777 // No need to flush SATBs 1778 return; 1779 } 1780 1781 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1782 ShenandoahThreadLocalData::set_force_satb_flush(t, true); 1783 } 1784 // The threads are not "acquiring" their thread-local data, but it does not 1785 // hurt to "release" the updates here anyway. 1786 OrderAccess::fence(); 1787 } 1788 1789 void ShenandoahHeap::set_gc_state_all_threads(char state) { 1790 for (JavaThreadIteratorWithHandle jtiwh; JavaThread *t = jtiwh.next(); ) { 1791 ShenandoahThreadLocalData::set_gc_state(t, state); 1792 } 1793 } 1794 1795 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1796 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1797 _gc_state.set_cond(mask, value); 1798 set_gc_state_all_threads(_gc_state.raw_value()); 1799 } 1800 1801 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1802 if (has_forwarded_objects()) { 1803 set_gc_state_mask(MARKING | UPDATEREFS, in_progress); 1804 } else { 1805 set_gc_state_mask(MARKING, in_progress); 1806 } 1807 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1808 } 1809 1810 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) { 1811 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress); 1812 ShenandoahBarrierSet::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1813 } 1814 1815 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1816 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1817 set_gc_state_mask(EVACUATION, in_progress); 1818 } 1819 1820 void ShenandoahHeap::ref_processing_init() { 1821 assert(_max_workers > 0, "Sanity"); 1822 1823 _ref_processor = 1824 new ReferenceProcessor(&_subject_to_discovery, // is_subject_to_discovery 1825 ParallelRefProcEnabled, // MT processing 1826 _max_workers, // Degree of MT processing 1827 true, // MT discovery 1828 _max_workers, // Degree of MT discovery 1829 false, // Reference discovery is not atomic 1830 NULL, // No closure, should be installed before use 1831 true); // Scale worker threads 1832 1833 shenandoah_assert_rp_isalive_not_installed(); 1834 } 1835 1836 GCTracer* ShenandoahHeap::tracer() { 1837 return shenandoah_policy()->tracer(); 1838 } 1839 1840 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1841 return _free_set->used(); 1842 } 1843 1844 bool ShenandoahHeap::try_cancel_gc() { 1845 while (true) { 1846 jbyte prev = _cancelled_gc.cmpxchg(CANCELLED, CANCELLABLE); 1847 if (prev == CANCELLABLE) return true; 1848 else if (prev == CANCELLED) return false; 1849 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 1850 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 1851 { 1852 // We need to provide a safepoint here, otherwise we might 1853 // spin forever if a SP is pending. 1854 ThreadBlockInVM sp(JavaThread::current()); 1855 SpinPause(); 1856 } 1857 } 1858 } 1859 1860 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 1861 if (try_cancel_gc()) { 1862 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 1863 log_info(gc)("%s", msg.buffer()); 1864 Events::log(Thread::current(), "%s", msg.buffer()); 1865 } 1866 } 1867 1868 uint ShenandoahHeap::max_workers() { 1869 return _max_workers; 1870 } 1871 1872 void ShenandoahHeap::stop() { 1873 // The shutdown sequence should be able to terminate when GC is running. 1874 1875 // Step 0. Notify policy to disable event recording. 1876 _shenandoah_policy->record_shutdown(); 1877 1878 // Step 1. Notify control thread that we are in shutdown. 1879 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 1880 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 1881 control_thread()->prepare_for_graceful_shutdown(); 1882 1883 // Step 2. Notify GC workers that we are cancelling GC. 1884 cancel_gc(GCCause::_shenandoah_stop_vm); 1885 1886 // Step 3. Wait until GC worker exits normally. 1887 control_thread()->stop(); 1888 1889 // Step 4. Stop String Dedup thread if it is active 1890 if (ShenandoahStringDedup::is_enabled()) { 1891 ShenandoahStringDedup::stop(); 1892 } 1893 } 1894 1895 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) { 1896 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled"); 1897 1898 ShenandoahGCPhase root_phase(full_gc ? 1899 ShenandoahPhaseTimings::full_gc_purge : 1900 ShenandoahPhaseTimings::purge); 1901 1902 ShenandoahIsAliveSelector alive; 1903 BoolObjectClosure* is_alive = alive.is_alive_closure(); 1904 1905 bool purged_class; 1906 1907 // Unload classes and purge SystemDictionary. 1908 { 1909 ShenandoahGCPhase phase(full_gc ? 1910 ShenandoahPhaseTimings::full_gc_purge_class_unload : 1911 ShenandoahPhaseTimings::purge_class_unload); 1912 purged_class = SystemDictionary::do_unloading(gc_timer()); 1913 } 1914 1915 { 1916 ShenandoahGCPhase phase(full_gc ? 1917 ShenandoahPhaseTimings::full_gc_purge_par : 1918 ShenandoahPhaseTimings::purge_par); 1919 uint active = _workers->active_workers(); 1920 ParallelCleaningTask unlink_task(is_alive, active, purged_class, true); 1921 _workers->run_task(&unlink_task); 1922 } 1923 1924 { 1925 ShenandoahGCPhase phase(full_gc ? 1926 ShenandoahPhaseTimings::full_gc_purge_cldg : 1927 ShenandoahPhaseTimings::purge_cldg); 1928 ClassLoaderDataGraph::purge(); 1929 } 1930 } 1931 1932 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 1933 set_gc_state_mask(HAS_FORWARDED, cond); 1934 } 1935 1936 void ShenandoahHeap::set_process_references(bool pr) { 1937 _process_references.set_cond(pr); 1938 } 1939 1940 void ShenandoahHeap::set_unload_classes(bool uc) { 1941 _unload_classes.set_cond(uc); 1942 } 1943 1944 bool ShenandoahHeap::process_references() const { 1945 return _process_references.is_set(); 1946 } 1947 1948 bool ShenandoahHeap::unload_classes() const { 1949 return _unload_classes.is_set(); 1950 } 1951 1952 address ShenandoahHeap::in_cset_fast_test_addr() { 1953 ShenandoahHeap* heap = ShenandoahHeap::heap(); 1954 assert(heap->collection_set() != NULL, "Sanity"); 1955 return (address) heap->collection_set()->biased_map_address(); 1956 } 1957 1958 address ShenandoahHeap::cancelled_gc_addr() { 1959 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 1960 } 1961 1962 address ShenandoahHeap::gc_state_addr() { 1963 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 1964 } 1965 1966 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 1967 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start); 1968 } 1969 1970 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 1971 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 1972 } 1973 1974 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 1975 _degenerated_gc_in_progress.set_cond(in_progress); 1976 } 1977 1978 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 1979 _full_gc_in_progress.set_cond(in_progress); 1980 } 1981 1982 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 1983 assert (is_full_gc_in_progress(), "should be"); 1984 _full_gc_move_in_progress.set_cond(in_progress); 1985 } 1986 1987 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 1988 set_gc_state_mask(UPDATEREFS, in_progress); 1989 } 1990 1991 void ShenandoahHeap::register_nmethod(nmethod* nm) { 1992 ShenandoahCodeRoots::add_nmethod(nm); 1993 } 1994 1995 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 1996 ShenandoahCodeRoots::remove_nmethod(nm); 1997 } 1998 1999 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 2000 ShenandoahHeapLocker locker(lock()); 2001 heap_region_containing(o)->make_pinned(); 2002 return o; 2003 } 2004 2005 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 2006 ShenandoahHeapLocker locker(lock()); 2007 heap_region_containing(o)->make_unpinned(); 2008 } 2009 2010 GCTimer* ShenandoahHeap::gc_timer() const { 2011 return _gc_timer; 2012 } 2013 2014 #ifdef ASSERT 2015 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 2016 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 2017 2018 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 2019 if (UseDynamicNumberOfGCThreads || 2020 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { 2021 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 2022 } else { 2023 // Use ParallelGCThreads inside safepoints 2024 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); 2025 } 2026 } else { 2027 if (UseDynamicNumberOfGCThreads || 2028 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { 2029 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2030 } else { 2031 // Use ConcGCThreads outside safepoints 2032 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2033 } 2034 } 2035 } 2036 #endif 2037 2038 ShenandoahVerifier* ShenandoahHeap::verifier() { 2039 guarantee(ShenandoahVerify, "Should be enabled"); 2040 assert (_verifier != NULL, "sanity"); 2041 return _verifier; 2042 } 2043 2044 template<class T> 2045 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2046 private: 2047 T cl; 2048 ShenandoahHeap* _heap; 2049 ShenandoahRegionIterator* _regions; 2050 bool _concurrent; 2051 public: 2052 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2053 AbstractGangTask("Concurrent Update References Task"), 2054 cl(T()), 2055 _heap(ShenandoahHeap::heap()), 2056 _regions(regions), 2057 _concurrent(concurrent) { 2058 } 2059 2060 void work(uint worker_id) { 2061 if (_concurrent) { 2062 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2063 ShenandoahSuspendibleThreadSetJoiner stsj(ShenandoahSuspendibleWorkers); 2064 do_work(); 2065 } else { 2066 ShenandoahParallelWorkerSession worker_session(worker_id); 2067 do_work(); 2068 } 2069 } 2070 2071 private: 2072 void do_work() { 2073 ShenandoahHeapRegion* r = _regions->next(); 2074 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2075 while (r != NULL) { 2076 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); 2077 assert (top_at_start_ur >= r->bottom(), "sanity"); 2078 if (r->is_active() && !r->is_cset()) { 2079 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); 2080 } 2081 if (ShenandoahPacing) { 2082 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); 2083 } 2084 if (_heap->check_cancelled_gc_and_yield(_concurrent)) { 2085 return; 2086 } 2087 r = _regions->next(); 2088 } 2089 } 2090 }; 2091 2092 void ShenandoahHeap::update_heap_references(bool concurrent) { 2093 ShenandoahUpdateHeapRefsTask<ShenandoahUpdateHeapRefsClosure> task(&_update_refs_iterator, concurrent); 2094 workers()->run_task(&task); 2095 } 2096 2097 void ShenandoahHeap::op_init_updaterefs() { 2098 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2099 2100 set_evacuation_in_progress(false); 2101 2102 retire_and_reset_gclabs(); 2103 2104 if (ShenandoahVerify) { 2105 if (!is_degenerated_gc_in_progress()) { 2106 verifier()->verify_roots_no_forwarded_except(ShenandoahRootVerifier::ThreadRoots); 2107 } 2108 verifier()->verify_before_updaterefs(); 2109 } 2110 2111 set_update_refs_in_progress(true); 2112 make_parsable(true); 2113 for (uint i = 0; i < num_regions(); i++) { 2114 ShenandoahHeapRegion* r = get_region(i); 2115 r->set_concurrent_iteration_safe_limit(r->top()); 2116 } 2117 2118 // Reset iterator. 2119 _update_refs_iterator.reset(); 2120 2121 if (ShenandoahPacing) { 2122 pacer()->setup_for_updaterefs(); 2123 } 2124 } 2125 2126 void ShenandoahHeap::op_final_updaterefs() { 2127 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2128 2129 // Check if there is left-over work, and finish it 2130 if (_update_refs_iterator.has_next()) { 2131 ShenandoahGCPhase final_work(ShenandoahPhaseTimings::final_update_refs_finish_work); 2132 2133 // Finish updating references where we left off. 2134 clear_cancelled_gc(); 2135 update_heap_references(false); 2136 } 2137 2138 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2139 // everything. On degenerated paths, cancelled gc would not be set anyway. 2140 if (cancelled_gc()) { 2141 clear_cancelled_gc(); 2142 } 2143 assert(!cancelled_gc(), "Should have been done right before"); 2144 2145 if (ShenandoahVerify && !is_degenerated_gc_in_progress()) { 2146 verifier()->verify_roots_no_forwarded_except(ShenandoahRootVerifier::ThreadRoots); 2147 } 2148 2149 if (is_degenerated_gc_in_progress()) { 2150 concurrent_mark()->update_roots(ShenandoahPhaseTimings::degen_gc_update_roots); 2151 } else { 2152 concurrent_mark()->update_thread_roots(ShenandoahPhaseTimings::final_update_refs_roots); 2153 } 2154 2155 ShenandoahGCPhase final_update_refs(ShenandoahPhaseTimings::final_update_refs_recycle); 2156 2157 trash_cset_regions(); 2158 set_has_forwarded_objects(false); 2159 set_update_refs_in_progress(false); 2160 2161 if (ShenandoahVerify) { 2162 verifier()->verify_roots_no_forwarded(); 2163 verifier()->verify_after_updaterefs(); 2164 } 2165 2166 if (VerifyAfterGC) { 2167 Universe::verify(); 2168 } 2169 2170 { 2171 ShenandoahHeapLocker locker(lock()); 2172 _free_set->rebuild(); 2173 } 2174 } 2175 2176 #ifdef ASSERT 2177 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { 2178 _lock.assert_owned_by_current_thread(); 2179 } 2180 2181 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { 2182 _lock.assert_not_owned_by_current_thread(); 2183 } 2184 2185 void ShenandoahHeap::assert_heaplock_or_safepoint() { 2186 _lock.assert_owned_by_current_thread_or_safepoint(); 2187 } 2188 #endif 2189 2190 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2191 print_on(st); 2192 print_heap_regions_on(st); 2193 } 2194 2195 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2196 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2197 2198 size_t regions_from = _bitmap_regions_per_slice * slice; 2199 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2200 for (size_t g = regions_from; g < regions_to; g++) { 2201 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2202 if (skip_self && g == r->region_number()) continue; 2203 if (get_region(g)->is_committed()) { 2204 return true; 2205 } 2206 } 2207 return false; 2208 } 2209 2210 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2211 assert_heaplock_owned_by_current_thread(); 2212 2213 // Bitmaps in special regions do not need commits 2214 if (_bitmap_region_special) { 2215 return true; 2216 } 2217 2218 if (is_bitmap_slice_committed(r, true)) { 2219 // Some other region from the group is already committed, meaning the bitmap 2220 // slice is already committed, we exit right away. 2221 return true; 2222 } 2223 2224 // Commit the bitmap slice: 2225 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2226 size_t off = _bitmap_bytes_per_slice * slice; 2227 size_t len = _bitmap_bytes_per_slice; 2228 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2229 return false; 2230 } 2231 return true; 2232 } 2233 2234 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2235 assert_heaplock_owned_by_current_thread(); 2236 2237 // Bitmaps in special regions do not need uncommits 2238 if (_bitmap_region_special) { 2239 return true; 2240 } 2241 2242 if (is_bitmap_slice_committed(r, true)) { 2243 // Some other region from the group is still committed, meaning the bitmap 2244 // slice is should stay committed, exit right away. 2245 return true; 2246 } 2247 2248 // Uncommit the bitmap slice: 2249 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2250 size_t off = _bitmap_bytes_per_slice * slice; 2251 size_t len = _bitmap_bytes_per_slice; 2252 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2253 return false; 2254 } 2255 return true; 2256 } 2257 2258 void ShenandoahHeap::safepoint_synchronize_begin() { 2259 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2260 SuspendibleThreadSet::synchronize(); 2261 } 2262 } 2263 2264 void ShenandoahHeap::safepoint_synchronize_end() { 2265 if (ShenandoahSuspendibleWorkers || UseStringDeduplication) { 2266 SuspendibleThreadSet::desynchronize(); 2267 } 2268 } 2269 2270 void ShenandoahHeap::vmop_entry_init_mark() { 2271 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2272 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2273 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2274 2275 try_inject_alloc_failure(); 2276 VM_ShenandoahInitMark op; 2277 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2278 } 2279 2280 void ShenandoahHeap::vmop_entry_final_mark() { 2281 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2282 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2283 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2284 2285 try_inject_alloc_failure(); 2286 VM_ShenandoahFinalMarkStartEvac op; 2287 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2288 } 2289 2290 void ShenandoahHeap::vmop_entry_final_evac() { 2291 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2292 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2293 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); 2294 2295 VM_ShenandoahFinalEvac op; 2296 VMThread::execute(&op); // jump to entry_final_evac under safepoint 2297 } 2298 2299 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2300 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2301 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2302 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2303 2304 try_inject_alloc_failure(); 2305 VM_ShenandoahInitUpdateRefs op; 2306 VMThread::execute(&op); 2307 } 2308 2309 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2310 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2311 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2312 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2313 2314 try_inject_alloc_failure(); 2315 VM_ShenandoahFinalUpdateRefs op; 2316 VMThread::execute(&op); 2317 } 2318 2319 void ShenandoahHeap::vmop_entry_init_traversal() { 2320 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2321 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2322 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross); 2323 2324 try_inject_alloc_failure(); 2325 VM_ShenandoahInitTraversalGC op; 2326 VMThread::execute(&op); 2327 } 2328 2329 void ShenandoahHeap::vmop_entry_final_traversal() { 2330 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2331 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2332 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross); 2333 2334 try_inject_alloc_failure(); 2335 VM_ShenandoahFinalTraversalGC op; 2336 VMThread::execute(&op); 2337 } 2338 2339 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2340 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2341 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2342 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2343 2344 try_inject_alloc_failure(); 2345 VM_ShenandoahFullGC op(cause); 2346 VMThread::execute(&op); 2347 } 2348 2349 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2350 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2351 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2352 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2353 2354 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2355 VMThread::execute(°enerated_gc); 2356 } 2357 2358 void ShenandoahHeap::entry_init_mark() { 2359 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2360 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2361 const char* msg = init_mark_event_message(); 2362 GCTraceTime(Info, gc) time(msg, gc_timer()); 2363 EventMark em("%s", msg); 2364 2365 ShenandoahWorkerScope scope(workers(), 2366 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2367 "init marking"); 2368 2369 op_init_mark(); 2370 } 2371 2372 void ShenandoahHeap::entry_final_mark() { 2373 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2374 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2375 const char* msg = final_mark_event_message(); 2376 GCTraceTime(Info, gc) time(msg, gc_timer()); 2377 EventMark em("%s", msg); 2378 2379 ShenandoahWorkerScope scope(workers(), 2380 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2381 "final marking"); 2382 2383 op_final_mark(); 2384 } 2385 2386 void ShenandoahHeap::entry_final_evac() { 2387 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); 2389 static const char* msg = "Pause Final Evac"; 2390 GCTraceTime(Info, gc) time(msg, gc_timer()); 2391 EventMark em("%s", msg); 2392 2393 op_final_evac(); 2394 } 2395 2396 void ShenandoahHeap::entry_init_updaterefs() { 2397 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2398 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2399 2400 static const char* msg = "Pause Init Update Refs"; 2401 GCTraceTime(Info, gc) time(msg, gc_timer()); 2402 EventMark em("%s", msg); 2403 2404 // No workers used in this phase, no setup required 2405 2406 op_init_updaterefs(); 2407 } 2408 2409 void ShenandoahHeap::entry_final_updaterefs() { 2410 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2411 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2412 2413 static const char* msg = "Pause Final Update Refs"; 2414 GCTraceTime(Info, gc) time(msg, gc_timer()); 2415 EventMark em("%s", msg); 2416 2417 ShenandoahWorkerScope scope(workers(), 2418 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2419 "final reference update"); 2420 2421 op_final_updaterefs(); 2422 } 2423 2424 void ShenandoahHeap::entry_init_traversal() { 2425 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2426 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc); 2427 2428 static const char* msg = "Pause Init Traversal"; 2429 GCTraceTime(Info, gc) time(msg, gc_timer()); 2430 EventMark em("%s", msg); 2431 2432 ShenandoahWorkerScope scope(workers(), 2433 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2434 "init traversal"); 2435 2436 op_init_traversal(); 2437 } 2438 2439 void ShenandoahHeap::entry_final_traversal() { 2440 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2441 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc); 2442 2443 static const char* msg = "Pause Final Traversal"; 2444 GCTraceTime(Info, gc) time(msg, gc_timer()); 2445 EventMark em("%s", msg); 2446 2447 ShenandoahWorkerScope scope(workers(), 2448 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2449 "final traversal"); 2450 2451 op_final_traversal(); 2452 } 2453 2454 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2455 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2456 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2457 2458 static const char* msg = "Pause Full"; 2459 GCTraceTime(Info, gc) time(msg, gc_timer(), cause, true); 2460 EventMark em("%s", msg); 2461 2462 ShenandoahWorkerScope scope(workers(), 2463 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2464 "full gc"); 2465 2466 op_full(cause); 2467 } 2468 2469 void ShenandoahHeap::entry_degenerated(int point) { 2470 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2471 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2472 2473 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2474 const char* msg = degen_event_message(dpoint); 2475 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2476 EventMark em("%s", msg); 2477 2478 ShenandoahWorkerScope scope(workers(), 2479 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2480 "stw degenerated gc"); 2481 2482 set_degenerated_gc_in_progress(true); 2483 op_degenerated(dpoint); 2484 set_degenerated_gc_in_progress(false); 2485 } 2486 2487 void ShenandoahHeap::entry_mark() { 2488 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2489 2490 const char* msg = conc_mark_event_message(); 2491 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2492 EventMark em("%s", msg); 2493 2494 ShenandoahWorkerScope scope(workers(), 2495 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2496 "concurrent marking"); 2497 2498 try_inject_alloc_failure(); 2499 op_mark(); 2500 } 2501 2502 void ShenandoahHeap::entry_evac() { 2503 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2504 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2505 2506 static const char* msg = "Concurrent evacuation"; 2507 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2508 EventMark em("%s", msg); 2509 2510 ShenandoahWorkerScope scope(workers(), 2511 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2512 "concurrent evacuation"); 2513 2514 try_inject_alloc_failure(); 2515 op_conc_evac(); 2516 } 2517 2518 void ShenandoahHeap::entry_updaterefs() { 2519 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2520 2521 static const char* msg = "Concurrent update references"; 2522 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2523 EventMark em("%s", msg); 2524 2525 ShenandoahWorkerScope scope(workers(), 2526 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2527 "concurrent reference update"); 2528 2529 try_inject_alloc_failure(); 2530 op_updaterefs(); 2531 } 2532 void ShenandoahHeap::entry_cleanup() { 2533 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2534 2535 static const char* msg = "Concurrent cleanup"; 2536 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2537 EventMark em("%s", msg); 2538 2539 // This phase does not use workers, no need for setup 2540 2541 try_inject_alloc_failure(); 2542 op_cleanup(); 2543 } 2544 2545 void ShenandoahHeap::entry_reset() { 2546 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2547 2548 static const char* msg = "Concurrent reset"; 2549 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2550 EventMark em("%s", msg); 2551 2552 ShenandoahWorkerScope scope(workers(), 2553 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2554 "concurrent reset"); 2555 2556 try_inject_alloc_failure(); 2557 op_reset(); 2558 } 2559 2560 void ShenandoahHeap::entry_preclean() { 2561 if (ShenandoahPreclean && process_references()) { 2562 static const char* msg = "Concurrent precleaning"; 2563 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2564 EventMark em("%s", msg); 2565 2566 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2567 2568 ShenandoahWorkerScope scope(workers(), 2569 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2570 "concurrent preclean", 2571 /* check_workers = */ false); 2572 2573 try_inject_alloc_failure(); 2574 op_preclean(); 2575 } 2576 } 2577 2578 void ShenandoahHeap::entry_traversal() { 2579 static const char* msg = "Concurrent traversal"; 2580 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2581 EventMark em("%s", msg); 2582 2583 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2584 2585 ShenandoahWorkerScope scope(workers(), 2586 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(), 2587 "concurrent traversal"); 2588 2589 try_inject_alloc_failure(); 2590 op_traversal(); 2591 } 2592 2593 void ShenandoahHeap::entry_uncommit(double shrink_before) { 2594 static const char *msg = "Concurrent uncommit"; 2595 GCTraceTime(Info, gc) time(msg, NULL, GCCause::_no_gc, true); 2596 EventMark em("%s", msg); 2597 2598 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 2599 2600 op_uncommit(shrink_before); 2601 } 2602 2603 void ShenandoahHeap::try_inject_alloc_failure() { 2604 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2605 _inject_alloc_failure.set(); 2606 os::naked_short_sleep(1); 2607 if (cancelled_gc()) { 2608 log_info(gc)("Allocation failure was successfully injected"); 2609 } 2610 } 2611 } 2612 2613 bool ShenandoahHeap::should_inject_alloc_failure() { 2614 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2615 } 2616 2617 void ShenandoahHeap::initialize_serviceability() { 2618 _memory_pool = new ShenandoahMemoryPool(this); 2619 _cycle_memory_manager.add_pool(_memory_pool); 2620 _stw_memory_manager.add_pool(_memory_pool); 2621 } 2622 2623 GrowableArray<GCMemoryManager*> ShenandoahHeap::memory_managers() { 2624 GrowableArray<GCMemoryManager*> memory_managers(2); 2625 memory_managers.append(&_cycle_memory_manager); 2626 memory_managers.append(&_stw_memory_manager); 2627 return memory_managers; 2628 } 2629 2630 GrowableArray<MemoryPool*> ShenandoahHeap::memory_pools() { 2631 GrowableArray<MemoryPool*> memory_pools(1); 2632 memory_pools.append(_memory_pool); 2633 return memory_pools; 2634 } 2635 2636 MemoryUsage ShenandoahHeap::memory_usage() { 2637 return _memory_pool->get_memory_usage(); 2638 } 2639 2640 void ShenandoahHeap::enter_evacuation() { 2641 _oom_evac_handler.enter_evacuation(); 2642 } 2643 2644 void ShenandoahHeap::leave_evacuation() { 2645 _oom_evac_handler.leave_evacuation(); 2646 } 2647 2648 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2649 _heap(ShenandoahHeap::heap()), 2650 _index(0) {} 2651 2652 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2653 _heap(heap), 2654 _index(0) {} 2655 2656 void ShenandoahRegionIterator::reset() { 2657 _index = 0; 2658 } 2659 2660 bool ShenandoahRegionIterator::has_next() const { 2661 return _index < _heap->num_regions(); 2662 } 2663 2664 char ShenandoahHeap::gc_state() const { 2665 return _gc_state.raw_value(); 2666 } 2667 2668 void ShenandoahHeap::deduplicate_string(oop str) { 2669 assert(java_lang_String::is_instance(str), "invariant"); 2670 2671 if (ShenandoahStringDedup::is_enabled()) { 2672 ShenandoahStringDedup::deduplicate(str); 2673 } 2674 } 2675 2676 const char* ShenandoahHeap::init_mark_event_message() const { 2677 bool update_refs = has_forwarded_objects(); 2678 bool proc_refs = process_references(); 2679 bool unload_cls = unload_classes(); 2680 2681 if (update_refs && proc_refs && unload_cls) { 2682 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; 2683 } else if (update_refs && proc_refs) { 2684 return "Pause Init Mark (update refs) (process weakrefs)"; 2685 } else if (update_refs && unload_cls) { 2686 return "Pause Init Mark (update refs) (unload classes)"; 2687 } else if (proc_refs && unload_cls) { 2688 return "Pause Init Mark (process weakrefs) (unload classes)"; 2689 } else if (update_refs) { 2690 return "Pause Init Mark (update refs)"; 2691 } else if (proc_refs) { 2692 return "Pause Init Mark (process weakrefs)"; 2693 } else if (unload_cls) { 2694 return "Pause Init Mark (unload classes)"; 2695 } else { 2696 return "Pause Init Mark"; 2697 } 2698 } 2699 2700 const char* ShenandoahHeap::final_mark_event_message() const { 2701 bool update_refs = has_forwarded_objects(); 2702 bool proc_refs = process_references(); 2703 bool unload_cls = unload_classes(); 2704 2705 if (update_refs && proc_refs && unload_cls) { 2706 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; 2707 } else if (update_refs && proc_refs) { 2708 return "Pause Final Mark (update refs) (process weakrefs)"; 2709 } else if (update_refs && unload_cls) { 2710 return "Pause Final Mark (update refs) (unload classes)"; 2711 } else if (proc_refs && unload_cls) { 2712 return "Pause Final Mark (process weakrefs) (unload classes)"; 2713 } else if (update_refs) { 2714 return "Pause Final Mark (update refs)"; 2715 } else if (proc_refs) { 2716 return "Pause Final Mark (process weakrefs)"; 2717 } else if (unload_cls) { 2718 return "Pause Final Mark (unload classes)"; 2719 } else { 2720 return "Pause Final Mark"; 2721 } 2722 } 2723 2724 const char* ShenandoahHeap::conc_mark_event_message() const { 2725 bool update_refs = has_forwarded_objects(); 2726 bool proc_refs = process_references(); 2727 bool unload_cls = unload_classes(); 2728 2729 if (update_refs && proc_refs && unload_cls) { 2730 return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; 2731 } else if (update_refs && proc_refs) { 2732 return "Concurrent marking (update refs) (process weakrefs)"; 2733 } else if (update_refs && unload_cls) { 2734 return "Concurrent marking (update refs) (unload classes)"; 2735 } else if (proc_refs && unload_cls) { 2736 return "Concurrent marking (process weakrefs) (unload classes)"; 2737 } else if (update_refs) { 2738 return "Concurrent marking (update refs)"; 2739 } else if (proc_refs) { 2740 return "Concurrent marking (process weakrefs)"; 2741 } else if (unload_cls) { 2742 return "Concurrent marking (unload classes)"; 2743 } else { 2744 return "Concurrent marking"; 2745 } 2746 } 2747 2748 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 2749 switch (point) { 2750 case _degenerated_unset: 2751 return "Pause Degenerated GC (<UNSET>)"; 2752 case _degenerated_traversal: 2753 return "Pause Degenerated GC (Traversal)"; 2754 case _degenerated_outside_cycle: 2755 return "Pause Degenerated GC (Outside of Cycle)"; 2756 case _degenerated_mark: 2757 return "Pause Degenerated GC (Mark)"; 2758 case _degenerated_evac: 2759 return "Pause Degenerated GC (Evacuation)"; 2760 case _degenerated_updaterefs: 2761 return "Pause Degenerated GC (Update Refs)"; 2762 default: 2763 ShouldNotReachHere(); 2764 return "ERROR"; 2765 } 2766 } 2767 2768 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2769 #ifdef ASSERT 2770 assert(_liveness_cache != NULL, "sanity"); 2771 assert(worker_id < _max_workers, "sanity"); 2772 for (uint i = 0; i < num_regions(); i++) { 2773 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 2774 } 2775 #endif 2776 return _liveness_cache[worker_id]; 2777 } 2778 2779 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 2780 assert(worker_id < _max_workers, "sanity"); 2781 assert(_liveness_cache != NULL, "sanity"); 2782 jushort* ld = _liveness_cache[worker_id]; 2783 for (uint i = 0; i < num_regions(); i++) { 2784 ShenandoahHeapRegion* r = get_region(i); 2785 jushort live = ld[i]; 2786 if (live > 0) { 2787 r->increase_live_data_gc_words(live); 2788 ld[i] = 0; 2789 } 2790 } 2791 }