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