1 /* 2 * Copyright (c) 2013, 2018, 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 27 #include "gc_implementation/shared/gcTimer.hpp" 28 #include "gc_implementation/shenandoah/shenandoahGCTraceTime.hpp" 29 #include "gc_implementation/shared/parallelCleaning.hpp" 30 31 #include "gc_implementation/shenandoah/shenandoahAllocTracker.hpp" 32 #include "gc_implementation/shenandoah/shenandoahBarrierSet.hpp" 33 #include "gc_implementation/shenandoah/shenandoahClosures.inline.hpp" 34 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 35 #include "gc_implementation/shenandoah/shenandoahCollectorPolicy.hpp" 36 #include "gc_implementation/shenandoah/shenandoahConcurrentMark.inline.hpp" 37 #include "gc_implementation/shenandoah/shenandoahControlThread.hpp" 38 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp" 39 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp" 40 #include "gc_implementation/shenandoah/shenandoahHeap.inline.hpp" 41 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 42 #include "gc_implementation/shenandoah/shenandoahHeapRegionSet.hpp" 43 #include "gc_implementation/shenandoah/shenandoahHeuristics.hpp" 44 #include "gc_implementation/shenandoah/shenandoahMarkCompact.hpp" 45 #include "gc_implementation/shenandoah/shenandoahMarkingContext.inline.hpp" 46 #include "gc_implementation/shenandoah/shenandoahMonitoringSupport.hpp" 47 #include "gc_implementation/shenandoah/shenandoahMetrics.hpp" 48 #include "gc_implementation/shenandoah/shenandoahNormalMode.hpp" 49 #include "gc_implementation/shenandoah/shenandoahOopClosures.inline.hpp" 50 #include "gc_implementation/shenandoah/shenandoahPacer.inline.hpp" 51 #include "gc_implementation/shenandoah/shenandoahPassiveMode.hpp" 52 #include "gc_implementation/shenandoah/shenandoahRootProcessor.hpp" 53 #include "gc_implementation/shenandoah/shenandoahTaskqueue.hpp" 54 #include "gc_implementation/shenandoah/shenandoahTraversalMode.hpp" 55 #include "gc_implementation/shenandoah/shenandoahUtils.hpp" 56 #include "gc_implementation/shenandoah/shenandoahVerifier.hpp" 57 #include "gc_implementation/shenandoah/shenandoahCodeRoots.hpp" 58 #include "gc_implementation/shenandoah/shenandoahVMOperations.hpp" 59 #include "gc_implementation/shenandoah/shenandoahWorkGroup.hpp" 60 #include "gc_implementation/shenandoah/shenandoahWorkerPolicy.hpp" 61 62 #include "memory/metaspace.hpp" 63 #include "runtime/vmThread.hpp" 64 #include "services/mallocTracker.hpp" 65 66 #ifdef ASSERT 67 template <class T> 68 void ShenandoahAssertToSpaceClosure::do_oop_nv(T* p) { 69 T o = oopDesc::load_heap_oop(p); 70 if (! oopDesc::is_null(o)) { 71 oop obj = oopDesc::decode_heap_oop_not_null(o); 72 shenandoah_assert_not_forwarded(p, obj); 73 } 74 } 75 76 void ShenandoahAssertToSpaceClosure::do_oop(narrowOop* p) { do_oop_nv(p); } 77 void ShenandoahAssertToSpaceClosure::do_oop(oop* p) { do_oop_nv(p); } 78 #endif 79 80 class ShenandoahPretouchHeapTask : public AbstractGangTask { 81 private: 82 ShenandoahRegionIterator _regions; 83 const size_t _page_size; 84 public: 85 ShenandoahPretouchHeapTask(size_t page_size) : 86 AbstractGangTask("Shenandoah Pretouch Heap"), 87 _page_size(page_size) {} 88 89 virtual void work(uint worker_id) { 90 ShenandoahHeapRegion* r = _regions.next(); 91 while (r != NULL) { 92 os::pretouch_memory((char*) r->bottom(), (char*) r->end()); 93 r = _regions.next(); 94 } 95 } 96 }; 97 98 class ShenandoahPretouchBitmapTask : public AbstractGangTask { 99 private: 100 ShenandoahRegionIterator _regions; 101 char* _bitmap_base; 102 const size_t _bitmap_size; 103 const size_t _page_size; 104 public: 105 ShenandoahPretouchBitmapTask(char* bitmap_base, size_t bitmap_size, size_t page_size) : 106 AbstractGangTask("Shenandoah Pretouch Bitmap"), 107 _bitmap_base(bitmap_base), 108 _bitmap_size(bitmap_size), 109 _page_size(page_size) {} 110 111 virtual void work(uint worker_id) { 112 ShenandoahHeapRegion* r = _regions.next(); 113 while (r != NULL) { 114 size_t start = r->region_number() * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 115 size_t end = (r->region_number() + 1) * ShenandoahHeapRegion::region_size_bytes() / MarkBitMap::heap_map_factor(); 116 assert (end <= _bitmap_size, err_msg("end is sane: " SIZE_FORMAT " < " SIZE_FORMAT, end, _bitmap_size)); 117 118 os::pretouch_memory(_bitmap_base + start, _bitmap_base + end); 119 120 r = _regions.next(); 121 } 122 } 123 }; 124 125 jint ShenandoahHeap::initialize() { 126 CollectedHeap::pre_initialize(); 127 128 initialize_heuristics(); 129 130 // 131 // Figure out heap sizing 132 // 133 134 size_t init_byte_size = collector_policy()->initial_heap_byte_size(); 135 size_t min_byte_size = collector_policy()->min_heap_byte_size(); 136 size_t max_byte_size = collector_policy()->max_heap_byte_size(); 137 size_t heap_alignment = collector_policy()->heap_alignment(); 138 139 size_t reg_size_bytes = ShenandoahHeapRegion::region_size_bytes(); 140 141 if (ShenandoahAlwaysPreTouch) { 142 // Enabled pre-touch means the entire heap is committed right away. 143 init_byte_size = max_byte_size; 144 } 145 146 Universe::check_alignment(max_byte_size, reg_size_bytes, "Shenandoah heap"); 147 Universe::check_alignment(init_byte_size, reg_size_bytes, "Shenandoah heap"); 148 149 _num_regions = ShenandoahHeapRegion::region_count(); 150 151 size_t num_committed_regions = init_byte_size / reg_size_bytes; 152 num_committed_regions = MIN2(num_committed_regions, _num_regions); 153 assert(num_committed_regions <= _num_regions, "sanity"); 154 _initial_size = num_committed_regions * reg_size_bytes; 155 156 size_t num_min_regions = min_byte_size / reg_size_bytes; 157 num_min_regions = MIN2(num_min_regions, _num_regions); 158 assert(num_min_regions <= _num_regions, "sanity"); 159 _minimum_size = num_min_regions * reg_size_bytes; 160 161 _committed = _initial_size; 162 163 size_t heap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 164 size_t bitmap_page_size = UseLargePages ? (size_t)os::large_page_size() : (size_t)os::vm_page_size(); 165 166 // 167 // Reserve and commit memory for heap 168 // 169 170 ReservedSpace heap_rs = Universe::reserve_heap(max_byte_size, heap_alignment); 171 _reserved.set_word_size(0); 172 _reserved.set_start((HeapWord*)heap_rs.base()); 173 _reserved.set_end((HeapWord*)(heap_rs.base() + heap_rs.size())); 174 _heap_region = MemRegion((HeapWord*)heap_rs.base(), heap_rs.size() / HeapWordSize); 175 _heap_region_special = heap_rs.special(); 176 177 assert((((size_t) base()) & ShenandoahHeapRegion::region_size_bytes_mask()) == 0, 178 err_msg("Misaligned heap: " PTR_FORMAT, p2i(base()))); 179 180 #if SHENANDOAH_OPTIMIZED_OBJTASK 181 // The optimized ObjArrayChunkedTask takes some bits away from the full object bits. 182 // Fail if we ever attempt to address more than we can. 183 if ((uintptr_t)(heap_rs.base() + heap_rs.size()) >= ObjArrayChunkedTask::max_addressable()) { 184 FormatBuffer<512> buf("Shenandoah reserved [" PTR_FORMAT ", " PTR_FORMAT") for the heap, \n" 185 "but max object address is " PTR_FORMAT ". Try to reduce heap size, or try other \n" 186 "VM options that allocate heap at lower addresses (HeapBaseMinAddress, AllocateHeapAt, etc).", 187 p2i(heap_rs.base()), p2i(heap_rs.base() + heap_rs.size()), ObjArrayChunkedTask::max_addressable()); 188 vm_exit_during_initialization("Fatal Error", buf); 189 } 190 #endif 191 192 ReservedSpace sh_rs = heap_rs.first_part(max_byte_size); 193 if (!_heap_region_special) { 194 os::commit_memory_or_exit(sh_rs.base(), _initial_size, heap_alignment, false, 195 "Cannot commit heap memory"); 196 } 197 198 // 199 // Reserve and commit memory for bitmap(s) 200 // 201 202 _bitmap_size = MarkBitMap::compute_size(heap_rs.size()); 203 _bitmap_size = align_size_up(_bitmap_size, bitmap_page_size); 204 205 size_t bitmap_bytes_per_region = reg_size_bytes / MarkBitMap::heap_map_factor(); 206 207 guarantee(bitmap_bytes_per_region != 0, 208 err_msg("Bitmap bytes per region should not be zero")); 209 guarantee(is_power_of_2(bitmap_bytes_per_region), 210 err_msg("Bitmap bytes per region should be power of two: " SIZE_FORMAT, bitmap_bytes_per_region)); 211 212 if (bitmap_page_size > bitmap_bytes_per_region) { 213 _bitmap_regions_per_slice = bitmap_page_size / bitmap_bytes_per_region; 214 _bitmap_bytes_per_slice = bitmap_page_size; 215 } else { 216 _bitmap_regions_per_slice = 1; 217 _bitmap_bytes_per_slice = bitmap_bytes_per_region; 218 } 219 220 guarantee(_bitmap_regions_per_slice >= 1, 221 err_msg("Should have at least one region per slice: " SIZE_FORMAT, 222 _bitmap_regions_per_slice)); 223 224 guarantee(((_bitmap_bytes_per_slice) % bitmap_page_size) == 0, 225 err_msg("Bitmap slices should be page-granular: bps = " SIZE_FORMAT ", page size = " SIZE_FORMAT, 226 _bitmap_bytes_per_slice, bitmap_page_size)); 227 228 ReservedSpace bitmap(_bitmap_size, bitmap_page_size); 229 MemTracker::record_virtual_memory_type(bitmap.base(), mtGC); 230 _bitmap_region = MemRegion((HeapWord*) bitmap.base(), bitmap.size() / HeapWordSize); 231 _bitmap_region_special = bitmap.special(); 232 233 size_t bitmap_init_commit = _bitmap_bytes_per_slice * 234 align_size_up(num_committed_regions, _bitmap_regions_per_slice) / _bitmap_regions_per_slice; 235 bitmap_init_commit = MIN2(_bitmap_size, bitmap_init_commit); 236 if (!_bitmap_region_special) { 237 os::commit_memory_or_exit((char *) _bitmap_region.start(), bitmap_init_commit, bitmap_page_size, false, 238 "Cannot commit bitmap memory"); 239 } 240 241 _marking_context = new ShenandoahMarkingContext(_heap_region, _bitmap_region, _num_regions); 242 243 if (ShenandoahVerify) { 244 ReservedSpace verify_bitmap(_bitmap_size, bitmap_page_size); 245 if (!verify_bitmap.special()) { 246 os::commit_memory_or_exit(verify_bitmap.base(), verify_bitmap.size(), bitmap_page_size, false, 247 "Cannot commit verification bitmap memory"); 248 } 249 MemTracker::record_virtual_memory_type(verify_bitmap.base(), mtGC); 250 MemRegion verify_bitmap_region = MemRegion((HeapWord *) verify_bitmap.base(), verify_bitmap.size() / HeapWordSize); 251 _verification_bit_map.initialize(_heap_region, verify_bitmap_region); 252 _verifier = new ShenandoahVerifier(this, &_verification_bit_map); 253 } 254 255 // Reserve aux bitmap for use in object_iterate(). We don't commit it here. 256 ReservedSpace aux_bitmap(_bitmap_size, bitmap_page_size); 257 MemTracker::record_virtual_memory_type(aux_bitmap.base(), mtGC); 258 _aux_bitmap_region = MemRegion((HeapWord*) aux_bitmap.base(), aux_bitmap.size() / HeapWordSize); 259 _aux_bitmap_region_special = aux_bitmap.special(); 260 _aux_bit_map.initialize(_heap_region, _aux_bitmap_region); 261 262 // 263 // Create regions and region sets 264 // 265 266 _regions = NEW_C_HEAP_ARRAY(ShenandoahHeapRegion*, _num_regions, mtGC); 267 _free_set = new ShenandoahFreeSet(this, _num_regions); 268 _collection_set = new ShenandoahCollectionSet(this, sh_rs.base(), sh_rs.size()); 269 270 { 271 ShenandoahHeapLocker locker(lock()); 272 273 size_t size_words = ShenandoahHeapRegion::region_size_words(); 274 275 for (size_t i = 0; i < _num_regions; i++) { 276 HeapWord* start = (HeapWord*)sh_rs.base() + size_words * i; 277 bool is_committed = i < num_committed_regions; 278 ShenandoahHeapRegion* r = new ShenandoahHeapRegion(this, start, size_words, i, is_committed); 279 280 _marking_context->initialize_top_at_mark_start(r); 281 _regions[i] = r; 282 assert(!collection_set()->is_in(i), "New region should not be in collection set"); 283 } 284 285 // Initialize to complete 286 _marking_context->mark_complete(); 287 288 _free_set->rebuild(); 289 } 290 291 if (ShenandoahAlwaysPreTouch) { 292 assert(!AlwaysPreTouch, "Should have been overridden"); 293 294 // For NUMA, it is important to pre-touch the storage under bitmaps with worker threads, 295 // before initialize() below zeroes it with initializing thread. For any given region, 296 // we touch the region and the corresponding bitmaps from the same thread. 297 ShenandoahPushWorkerScope scope(workers(), _max_workers, false); 298 299 size_t pretouch_heap_page_size = heap_page_size; 300 size_t pretouch_bitmap_page_size = bitmap_page_size; 301 302 #ifdef LINUX 303 // UseTransparentHugePages would madvise that backing memory can be coalesced into huge 304 // pages. But, the kernel needs to know that every small page is used, in order to coalesce 305 // them into huge one. Therefore, we need to pretouch with smaller pages. 306 if (UseTransparentHugePages) { 307 pretouch_heap_page_size = (size_t)os::vm_page_size(); 308 pretouch_bitmap_page_size = (size_t)os::vm_page_size(); 309 } 310 #endif 311 312 // OS memory managers may want to coalesce back-to-back pages. Make their jobs 313 // simpler by pre-touching continuous spaces (heap and bitmap) separately. 314 315 log_info(gc, init)("Pretouch bitmap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 316 _num_regions, pretouch_bitmap_page_size); 317 ShenandoahPretouchBitmapTask bcl(bitmap.base(), _bitmap_size, pretouch_bitmap_page_size); 318 _workers->run_task(&bcl); 319 320 log_info(gc, init)("Pretouch heap: " SIZE_FORMAT " regions, " SIZE_FORMAT " bytes page", 321 _num_regions, pretouch_heap_page_size); 322 ShenandoahPretouchHeapTask hcl(pretouch_heap_page_size); 323 _workers->run_task(&hcl); 324 } 325 326 // 327 // Initialize the rest of GC subsystems 328 // 329 330 set_barrier_set(new ShenandoahBarrierSet(this)); 331 332 _liveness_cache = NEW_C_HEAP_ARRAY(jushort*, _max_workers, mtGC); 333 for (uint worker = 0; worker < _max_workers; worker++) { 334 _liveness_cache[worker] = NEW_C_HEAP_ARRAY(jushort, _num_regions, mtGC); 335 Copy::fill_to_bytes(_liveness_cache[worker], _num_regions * sizeof(jushort)); 336 } 337 338 // The call below uses stuff (the SATB* things) that are in G1, but probably 339 // belong into a shared location. 340 JavaThread::satb_mark_queue_set().initialize(SATB_Q_CBL_mon, 341 SATB_Q_FL_lock, 342 20 /*G1SATBProcessCompletedThreshold */, 343 Shared_SATB_Q_lock); 344 345 _monitoring_support = new ShenandoahMonitoringSupport(this); 346 _phase_timings = new ShenandoahPhaseTimings(); 347 ShenandoahStringDedup::initialize(); 348 ShenandoahCodeRoots::initialize(); 349 350 if (ShenandoahAllocationTrace) { 351 _alloc_tracker = new ShenandoahAllocTracker(); 352 } 353 354 if (ShenandoahPacing) { 355 _pacer = new ShenandoahPacer(this); 356 _pacer->setup_for_idle(); 357 } else { 358 _pacer = NULL; 359 } 360 361 _traversal_gc = strcmp(ShenandoahGCMode, "traversal") == 0 ? 362 new ShenandoahTraversalGC(this, _num_regions) : 363 NULL; 364 365 _control_thread = new ShenandoahControlThread(); 366 367 log_info(gc, init)("Initialize Shenandoah heap: " SIZE_FORMAT "%s initial, " SIZE_FORMAT "%s min, " SIZE_FORMAT "%s max", 368 byte_size_in_proper_unit(_initial_size), proper_unit_for_byte_size(_initial_size), 369 byte_size_in_proper_unit(_minimum_size), proper_unit_for_byte_size(_minimum_size), 370 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()) 371 ); 372 373 return JNI_OK; 374 } 375 376 #ifdef _MSC_VER 377 #pragma warning( push ) 378 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list 379 #endif 380 381 void ShenandoahHeap::initialize_heuristics() { 382 if (ShenandoahGCMode != NULL) { 383 if (strcmp(ShenandoahGCMode, "traversal") == 0) { 384 _gc_mode = new ShenandoahTraversalMode(); 385 } else if (strcmp(ShenandoahGCMode, "normal") == 0) { 386 _gc_mode = new ShenandoahNormalMode(); 387 } else if (strcmp(ShenandoahGCMode, "passive") == 0) { 388 _gc_mode = new ShenandoahPassiveMode(); 389 } else { 390 vm_exit_during_initialization("Unknown -XX:ShenandoahGCMode option"); 391 } 392 } else { 393 ShouldNotReachHere(); 394 } 395 _gc_mode->initialize_flags(); 396 _heuristics = _gc_mode->initialize_heuristics(); 397 398 if (_heuristics->is_diagnostic() && !UnlockDiagnosticVMOptions) { 399 vm_exit_during_initialization( 400 err_msg("Heuristics \"%s\" is diagnostic, and must be enabled via -XX:+UnlockDiagnosticVMOptions.", 401 _heuristics->name())); 402 } 403 if (_heuristics->is_experimental() && !UnlockExperimentalVMOptions) { 404 vm_exit_during_initialization( 405 err_msg("Heuristics \"%s\" is experimental, and must be enabled via -XX:+UnlockExperimentalVMOptions.", 406 _heuristics->name())); 407 } 408 log_info(gc, init)("Shenandoah heuristics: %s", 409 _heuristics->name()); 410 } 411 412 ShenandoahHeap::ShenandoahHeap(ShenandoahCollectorPolicy* policy) : 413 SharedHeap(policy), 414 _shenandoah_policy(policy), 415 _heap_region_special(false), 416 _regions(NULL), 417 _free_set(NULL), 418 _collection_set(NULL), 419 _traversal_gc(NULL), 420 _update_refs_iterator(this), 421 _bytes_allocated_since_gc_start(0), 422 _max_workers((uint)MAX2(ConcGCThreads, ParallelGCThreads)), 423 _ref_processor(NULL), 424 _marking_context(NULL), 425 _bitmap_size(0), 426 _bitmap_regions_per_slice(0), 427 _bitmap_bytes_per_slice(0), 428 _bitmap_region_special(false), 429 _aux_bitmap_region_special(false), 430 _liveness_cache(NULL), 431 _aux_bit_map(), 432 _verifier(NULL), 433 _pacer(NULL), 434 _gc_timer(new (ResourceObj::C_HEAP, mtGC) ConcurrentGCTimer()), 435 _phase_timings(NULL), 436 _alloc_tracker(NULL) 437 { 438 log_info(gc, init)("GC threads: " UINTX_FORMAT " parallel, " UINTX_FORMAT " concurrent", ParallelGCThreads, ConcGCThreads); 439 log_info(gc, init)("Reference processing: %s", ParallelRefProcEnabled ? "parallel" : "serial"); 440 441 _scm = new ShenandoahConcurrentMark(); 442 443 _full_gc = new ShenandoahMarkCompact(); 444 _used = 0; 445 446 _max_workers = MAX2(_max_workers, 1U); 447 448 // SharedHeap did not initialize this for us, and we want our own workgang anyway. 449 assert(SharedHeap::_workers == NULL && _workers == NULL, "Should not be initialized yet"); 450 _workers = new ShenandoahWorkGang("Shenandoah GC Threads", _max_workers, 451 /* are_GC_task_threads */true, 452 /* are_ConcurrentGC_threads */false); 453 if (_workers == NULL) { 454 vm_exit_during_initialization("Failed necessary allocation."); 455 } else { 456 _workers->initialize_workers(); 457 } 458 assert(SharedHeap::_workers == _workers, "Sanity: initialized the correct field"); 459 } 460 461 #ifdef _MSC_VER 462 #pragma warning( pop ) 463 #endif 464 465 class ShenandoahResetBitmapTask : public AbstractGangTask { 466 private: 467 ShenandoahRegionIterator _regions; 468 469 public: 470 ShenandoahResetBitmapTask() : 471 AbstractGangTask("Parallel Reset Bitmap Task") {} 472 473 void work(uint worker_id) { 474 ShenandoahHeapRegion* region = _regions.next(); 475 ShenandoahHeap* heap = ShenandoahHeap::heap(); 476 ShenandoahMarkingContext* const ctx = heap->marking_context(); 477 while (region != NULL) { 478 if (heap->is_bitmap_slice_committed(region)) { 479 ctx->clear_bitmap(region); 480 } 481 region = _regions.next(); 482 } 483 } 484 }; 485 486 void ShenandoahHeap::reset_mark_bitmap() { 487 assert_gc_workers(_workers->active_workers()); 488 mark_incomplete_marking_context(); 489 490 ShenandoahResetBitmapTask task; 491 _workers->run_task(&task); 492 } 493 494 void ShenandoahHeap::print_on(outputStream* st) const { 495 st->print_cr("Shenandoah Heap"); 496 st->print_cr(" " SIZE_FORMAT "%s total, " SIZE_FORMAT "%s committed, " SIZE_FORMAT "%s used", 497 byte_size_in_proper_unit(max_capacity()), proper_unit_for_byte_size(max_capacity()), 498 byte_size_in_proper_unit(committed()), proper_unit_for_byte_size(committed()), 499 byte_size_in_proper_unit(used()), proper_unit_for_byte_size(used())); 500 st->print_cr(" " SIZE_FORMAT " x " SIZE_FORMAT"%s regions", 501 num_regions(), 502 byte_size_in_proper_unit(ShenandoahHeapRegion::region_size_bytes()), 503 proper_unit_for_byte_size(ShenandoahHeapRegion::region_size_bytes())); 504 505 st->print("Status: "); 506 if (has_forwarded_objects()) st->print("has forwarded objects, "); 507 if (is_concurrent_mark_in_progress()) st->print("marking, "); 508 if (is_evacuation_in_progress()) st->print("evacuating, "); 509 if (is_update_refs_in_progress()) st->print("updating refs, "); 510 if (is_concurrent_traversal_in_progress()) st->print("traversal, "); 511 if (is_degenerated_gc_in_progress()) st->print("degenerated gc, "); 512 if (is_full_gc_in_progress()) st->print("full gc, "); 513 if (is_full_gc_move_in_progress()) st->print("full gc move, "); 514 515 if (cancelled_gc()) { 516 st->print("cancelled"); 517 } else { 518 st->print("not cancelled"); 519 } 520 st->cr(); 521 522 st->print_cr("Reserved region:"); 523 st->print_cr(" - [" PTR_FORMAT ", " PTR_FORMAT ") ", 524 p2i(reserved_region().start()), 525 p2i(reserved_region().end())); 526 527 ShenandoahCollectionSet* cset = collection_set(); 528 st->print_cr("Collection set:"); 529 if (cset != NULL) { 530 st->print_cr(" - map (vanilla): " PTR_FORMAT, p2i(cset->map_address())); 531 st->print_cr(" - map (biased): " PTR_FORMAT, p2i(cset->biased_map_address())); 532 } else { 533 st->print_cr(" (NULL)"); 534 } 535 536 st->cr(); 537 MetaspaceAux::print_on(st); 538 539 if (Verbose) { 540 print_heap_regions_on(st); 541 } 542 } 543 544 class ShenandoahInitGCLABClosure : public ThreadClosure { 545 public: 546 void do_thread(Thread* thread) { 547 assert(thread == NULL || !thread->is_Java_thread(), "Don't expect JavaThread this early"); 548 if (thread != NULL && thread->is_Worker_thread()) { 549 thread->gclab().initialize(true); 550 } 551 } 552 }; 553 554 void ShenandoahHeap::post_initialize() { 555 if (UseTLAB) { 556 MutexLocker ml(Threads_lock); 557 558 ShenandoahInitGCLABClosure init_gclabs; 559 Threads::threads_do(&init_gclabs); 560 } 561 562 _scm->initialize(_max_workers); 563 _full_gc->initialize(_gc_timer); 564 565 ref_processing_init(); 566 567 _heuristics->initialize(); 568 } 569 570 size_t ShenandoahHeap::used() const { 571 OrderAccess::acquire(); 572 return (size_t) _used; 573 } 574 575 size_t ShenandoahHeap::committed() const { 576 OrderAccess::acquire(); 577 return _committed; 578 } 579 580 void ShenandoahHeap::increase_committed(size_t bytes) { 581 assert_heaplock_or_safepoint(); 582 _committed += bytes; 583 } 584 585 void ShenandoahHeap::decrease_committed(size_t bytes) { 586 assert_heaplock_or_safepoint(); 587 _committed -= bytes; 588 } 589 590 void ShenandoahHeap::increase_used(size_t bytes) { 591 Atomic::add(bytes, &_used); 592 } 593 594 void ShenandoahHeap::set_used(size_t bytes) { 595 OrderAccess::release_store_fence(&_used, bytes); 596 } 597 598 void ShenandoahHeap::decrease_used(size_t bytes) { 599 assert(used() >= bytes, "never decrease heap size by more than we've left"); 600 Atomic::add(-(jlong)bytes, &_used); 601 } 602 603 void ShenandoahHeap::increase_allocated(size_t bytes) { 604 Atomic::add(bytes, &_bytes_allocated_since_gc_start); 605 } 606 607 void ShenandoahHeap::notify_mutator_alloc_words(size_t words, bool waste) { 608 size_t bytes = words * HeapWordSize; 609 if (!waste) { 610 increase_used(bytes); 611 } 612 increase_allocated(bytes); 613 if (ShenandoahPacing) { 614 control_thread()->pacing_notify_alloc(words); 615 if (waste) { 616 pacer()->claim_for_alloc(words, true); 617 } 618 } 619 } 620 621 size_t ShenandoahHeap::capacity() const { 622 return committed(); 623 } 624 625 size_t ShenandoahHeap::max_capacity() const { 626 return _num_regions * ShenandoahHeapRegion::region_size_bytes(); 627 } 628 629 size_t ShenandoahHeap::min_capacity() const { 630 return _minimum_size; 631 } 632 633 size_t ShenandoahHeap::initial_capacity() const { 634 return _initial_size; 635 } 636 637 bool ShenandoahHeap::is_in(const void* p) const { 638 HeapWord* heap_base = (HeapWord*) base(); 639 HeapWord* last_region_end = heap_base + ShenandoahHeapRegion::region_size_words() * num_regions(); 640 return p >= heap_base && p < last_region_end; 641 } 642 643 void ShenandoahHeap::op_uncommit(double shrink_before) { 644 assert (ShenandoahUncommit, "should be enabled"); 645 646 // Application allocates from the beginning of the heap, and GC allocates at 647 // the end of it. It is more efficient to uncommit from the end, so that applications 648 // could enjoy the near committed regions. GC allocations are much less frequent, 649 // and therefore can accept the committing costs. 650 651 size_t count = 0; 652 for (size_t i = num_regions(); i > 0; i--) { // care about size_t underflow 653 ShenandoahHeapRegion* r = get_region(i - 1); 654 if (r->is_empty_committed() && (r->empty_time() < shrink_before)) { 655 ShenandoahHeapLocker locker(lock()); 656 if (r->is_empty_committed()) { 657 // Do not uncommit below minimal capacity 658 if (committed() < min_capacity() + ShenandoahHeapRegion::region_size_bytes()) { 659 break; 660 } 661 662 r->make_uncommitted(); 663 count++; 664 } 665 } 666 SpinPause(); // allow allocators to take the lock 667 } 668 669 if (count > 0) { 670 _control_thread->notify_heap_changed(); 671 } 672 } 673 674 HeapWord* ShenandoahHeap::allocate_from_gclab_slow(Thread* thread, size_t size) { 675 // Retain tlab and allocate object in shared space if 676 // the amount free in the tlab is too large to discard. 677 if (thread->gclab().free() > thread->gclab().refill_waste_limit()) { 678 thread->gclab().record_slow_allocation(size); 679 return NULL; 680 } 681 682 // Discard gclab and allocate a new one. 683 // To minimize fragmentation, the last GCLAB may be smaller than the rest. 684 size_t new_gclab_size = thread->gclab().compute_size(size); 685 686 thread->gclab().clear_before_allocation(); 687 688 if (new_gclab_size == 0) { 689 return NULL; 690 } 691 692 // Allocated object should fit in new GCLAB, and new_gclab_size should be larger than min 693 size_t min_size = MAX2(size + ThreadLocalAllocBuffer::alignment_reserve(), ThreadLocalAllocBuffer::min_size()); 694 new_gclab_size = MAX2(new_gclab_size, min_size); 695 696 // Allocate a new GCLAB... 697 size_t actual_size = 0; 698 HeapWord* obj = allocate_new_gclab(min_size, new_gclab_size, &actual_size); 699 700 if (obj == NULL) { 701 return NULL; 702 } 703 704 assert (size <= actual_size, "allocation should fit"); 705 706 if (ZeroTLAB) { 707 // ..and clear it. 708 Copy::zero_to_words(obj, actual_size); 709 } else { 710 // ...and zap just allocated object. 711 #ifdef ASSERT 712 // Skip mangling the space corresponding to the object header to 713 // ensure that the returned space is not considered parsable by 714 // any concurrent GC thread. 715 size_t hdr_size = oopDesc::header_size(); 716 Copy::fill_to_words(obj + hdr_size, actual_size - hdr_size, badHeapWordVal); 717 #endif // ASSERT 718 } 719 thread->gclab().fill(obj, obj + size, actual_size); 720 return obj; 721 } 722 723 HeapWord* ShenandoahHeap::allocate_new_tlab(size_t word_size) { 724 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_tlab(word_size); 725 return allocate_memory(req); 726 } 727 728 HeapWord* ShenandoahHeap::allocate_new_gclab(size_t min_size, 729 size_t word_size, 730 size_t* actual_size) { 731 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_gclab(min_size, word_size); 732 HeapWord* res = allocate_memory(req); 733 if (res != NULL) { 734 *actual_size = req.actual_size(); 735 } else { 736 *actual_size = 0; 737 } 738 return res; 739 } 740 741 ShenandoahHeap* ShenandoahHeap::heap() { 742 CollectedHeap* heap = Universe::heap(); 743 assert(heap != NULL, "Unitialized access to ShenandoahHeap::heap()"); 744 assert(heap->kind() == CollectedHeap::ShenandoahHeap, "not a shenandoah heap"); 745 return (ShenandoahHeap*) heap; 746 } 747 748 ShenandoahHeap* ShenandoahHeap::heap_no_check() { 749 CollectedHeap* heap = Universe::heap(); 750 return (ShenandoahHeap*) heap; 751 } 752 753 HeapWord* ShenandoahHeap::allocate_memory(ShenandoahAllocRequest& req) { 754 ShenandoahAllocTrace trace_alloc(req.size(), req.type()); 755 756 intptr_t pacer_epoch = 0; 757 bool in_new_region = false; 758 HeapWord* result = NULL; 759 760 if (req.is_mutator_alloc()) { 761 if (ShenandoahPacing) { 762 pacer()->pace_for_alloc(req.size()); 763 pacer_epoch = pacer()->epoch(); 764 } 765 766 if (!ShenandoahAllocFailureALot || !should_inject_alloc_failure()) { 767 result = allocate_memory_under_lock(req, in_new_region); 768 } 769 770 // Allocation failed, block until control thread reacted, then retry allocation. 771 // 772 // It might happen that one of the threads requesting allocation would unblock 773 // way later after GC happened, only to fail the second allocation, because 774 // other threads have already depleted the free storage. In this case, a better 775 // strategy is to try again, as long as GC makes progress. 776 // 777 // Then, we need to make sure the allocation was retried after at least one 778 // Full GC, which means we want to try more than ShenandoahFullGCThreshold times. 779 780 size_t tries = 0; 781 782 while (result == NULL && _progress_last_gc.is_set()) { 783 tries++; 784 control_thread()->handle_alloc_failure(req.size()); 785 result = allocate_memory_under_lock(req, in_new_region); 786 } 787 788 while (result == NULL && tries <= ShenandoahFullGCThreshold) { 789 tries++; 790 control_thread()->handle_alloc_failure(req.size()); 791 result = allocate_memory_under_lock(req, in_new_region); 792 } 793 794 } else { 795 assert(req.is_gc_alloc(), "Can only accept GC allocs here"); 796 result = allocate_memory_under_lock(req, in_new_region); 797 // Do not call handle_alloc_failure() here, because we cannot block. 798 // The allocation failure would be handled by the WB slowpath with handle_alloc_failure_evac(). 799 } 800 801 if (in_new_region) { 802 control_thread()->notify_heap_changed(); 803 } 804 805 if (result != NULL) { 806 size_t requested = req.size(); 807 size_t actual = req.actual_size(); 808 809 assert (req.is_lab_alloc() || (requested == actual), 810 err_msg("Only LAB allocations are elastic: %s, requested = " SIZE_FORMAT ", actual = " SIZE_FORMAT, 811 ShenandoahAllocRequest::alloc_type_to_string(req.type()), requested, actual)); 812 813 if (req.is_mutator_alloc()) { 814 notify_mutator_alloc_words(actual, false); 815 816 // If we requested more than we were granted, give the rest back to pacer. 817 // This only matters if we are in the same pacing epoch: do not try to unpace 818 // over the budget for the other phase. 819 if (ShenandoahPacing && (pacer_epoch > 0) && (requested > actual)) { 820 pacer()->unpace_for_alloc(pacer_epoch, requested - actual); 821 } 822 } else { 823 increase_used(actual*HeapWordSize); 824 } 825 } 826 827 return result; 828 } 829 830 HeapWord* ShenandoahHeap::allocate_memory_under_lock(ShenandoahAllocRequest& req, bool& in_new_region) { 831 ShenandoahHeapLocker locker(lock()); 832 return _free_set->allocate(req, in_new_region); 833 } 834 835 HeapWord* ShenandoahHeap::mem_allocate(size_t size, 836 bool* gc_overhead_limit_was_exceeded) { 837 ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared(size); 838 HeapWord* result = allocate_memory(req); 839 if (result != NULL) { 840 assert(! in_collection_set(result), "never allocate in targetted region"); 841 return result; 842 } else { 843 return NULL; 844 } 845 } 846 847 class ShenandoahConcurrentEvacuateRegionObjectClosure : public ObjectClosure { 848 private: 849 ShenandoahHeap* const _heap; 850 Thread* const _thread; 851 public: 852 ShenandoahConcurrentEvacuateRegionObjectClosure(ShenandoahHeap* heap) : 853 _heap(heap), _thread(Thread::current()) {} 854 855 void do_object(oop p) { 856 shenandoah_assert_marked(NULL, p); 857 if (!p->is_forwarded()) { 858 _heap->evacuate_object(p, _thread); 859 } 860 } 861 }; 862 863 class ShenandoahEvacuationTask : public AbstractGangTask { 864 private: 865 ShenandoahHeap* const _sh; 866 ShenandoahCollectionSet* const _cs; 867 bool _concurrent; 868 public: 869 ShenandoahEvacuationTask(ShenandoahHeap* sh, 870 ShenandoahCollectionSet* cs, 871 bool concurrent) : 872 AbstractGangTask("Parallel Evacuation Task"), 873 _sh(sh), 874 _cs(cs), 875 _concurrent(concurrent) 876 {} 877 878 void work(uint worker_id) { 879 ShenandoahEvacOOMScope oom_evac_scope; 880 if (_concurrent) { 881 ShenandoahConcurrentWorkerSession worker_session(worker_id); 882 do_work(); 883 } else { 884 ShenandoahParallelWorkerSession worker_session(worker_id); 885 do_work(); 886 } 887 } 888 889 private: 890 void do_work() { 891 ShenandoahConcurrentEvacuateRegionObjectClosure cl(_sh); 892 ShenandoahHeapRegion* r; 893 while ((r =_cs->claim_next()) != NULL) { 894 assert(r->has_live(), err_msg("Region " SIZE_FORMAT " should have been reclaimed early", r->region_number())); 895 _sh->marked_object_iterate(r, &cl); 896 897 if (ShenandoahPacing) { 898 _sh->pacer()->report_evac(r->used() >> LogHeapWordSize); 899 } 900 901 if (_sh->cancelled_gc()) { 902 break; 903 } 904 } 905 } 906 }; 907 908 void ShenandoahHeap::trash_cset_regions() { 909 ShenandoahHeapLocker locker(lock()); 910 911 ShenandoahCollectionSet* set = collection_set(); 912 ShenandoahHeapRegion* r; 913 set->clear_current_index(); 914 while ((r = set->next()) != NULL) { 915 r->make_trash(); 916 } 917 collection_set()->clear(); 918 } 919 920 void ShenandoahHeap::print_heap_regions_on(outputStream* st) const { 921 st->print_cr("Heap Regions:"); 922 st->print_cr("EU=empty-uncommitted, EC=empty-committed, R=regular, H=humongous start, HC=humongous continuation, CS=collection set, T=trash, P=pinned"); 923 st->print_cr("BTE=bottom/top/end, U=used, T=TLAB allocs, G=GCLAB allocs, S=shared allocs, L=live data"); 924 st->print_cr("R=root, CP=critical pins, TAMS=top-at-mark-start (previous, next)"); 925 926 for (size_t i = 0; i < num_regions(); i++) { 927 get_region(i)->print_on(st); 928 } 929 } 930 931 void ShenandoahHeap::trash_humongous_region_at(ShenandoahHeapRegion* start) { 932 assert(start->is_humongous_start(), "reclaim regions starting with the first one"); 933 934 oop humongous_obj = oop(start->bottom()); 935 size_t size = humongous_obj->size(); 936 size_t required_regions = ShenandoahHeapRegion::required_regions(size * HeapWordSize); 937 size_t index = start->region_number() + required_regions - 1; 938 939 assert(!start->has_live(), "liveness must be zero"); 940 941 for(size_t i = 0; i < required_regions; i++) { 942 // Reclaim from tail. Otherwise, assertion fails when printing region to trace log, 943 // as it expects that every region belongs to a humongous region starting with a humongous start region. 944 ShenandoahHeapRegion* region = get_region(index --); 945 946 assert(region->is_humongous(), "expect correct humongous start or continuation"); 947 assert(!region->is_cset(), "Humongous region should not be in collection set"); 948 949 region->make_trash_immediate(); 950 } 951 } 952 953 class ShenandoahRetireGCLABClosure : public ThreadClosure { 954 private: 955 bool _retire; 956 public: 957 ShenandoahRetireGCLABClosure(bool retire) : _retire(retire) {}; 958 959 void do_thread(Thread* thread) { 960 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 961 thread->gclab().make_parsable(_retire); 962 } 963 }; 964 965 void ShenandoahHeap::make_parsable(bool retire_tlabs) { 966 if (UseTLAB) { 967 CollectedHeap::ensure_parsability(retire_tlabs); 968 ShenandoahRetireGCLABClosure cl(retire_tlabs); 969 Threads::java_threads_do(&cl); 970 _workers->threads_do(&cl); 971 } 972 } 973 974 class ShenandoahEvacuateUpdateRootsTask : public AbstractGangTask { 975 private: 976 ShenandoahRootEvacuator* _rp; 977 978 public: 979 ShenandoahEvacuateUpdateRootsTask(ShenandoahRootEvacuator* rp) : 980 AbstractGangTask("Shenandoah evacuate and update roots"), 981 _rp(rp) {} 982 983 void work(uint worker_id) { 984 ShenandoahParallelWorkerSession worker_session(worker_id); 985 ShenandoahEvacOOMScope oom_evac_scope; 986 ShenandoahEvacuateUpdateRootsClosure cl; 987 988 MarkingCodeBlobClosure blobsCl(&cl, CodeBlobToOopClosure::FixRelocations); 989 _rp->process_evacuate_roots(&cl, &blobsCl, worker_id); 990 } 991 }; 992 993 void ShenandoahHeap::evacuate_and_update_roots() { 994 COMPILER2_PRESENT(DerivedPointerTable::clear()); 995 996 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 997 998 { 999 ShenandoahRootEvacuator rp(this, workers()->active_workers(), ShenandoahPhaseTimings::init_evac); 1000 ShenandoahEvacuateUpdateRootsTask roots_task(&rp); 1001 workers()->run_task(&roots_task); 1002 } 1003 1004 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); 1005 } 1006 1007 void ShenandoahHeap::roots_iterate(OopClosure* cl) { 1008 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only iterate roots while world is stopped"); 1009 1010 CodeBlobToOopClosure blobsCl(cl, false); 1011 CLDToOopClosure cldCl(cl); 1012 1013 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases); 1014 rp.process_all_roots(cl, NULL, &cldCl, &blobsCl, NULL, 0); 1015 } 1016 1017 size_t ShenandoahHeap::unsafe_max_tlab_alloc(Thread *thread) const { 1018 // Returns size in bytes 1019 return MIN2(_free_set->unsafe_peek_free(), ShenandoahHeapRegion::max_tlab_size_bytes()); 1020 } 1021 1022 size_t ShenandoahHeap::max_tlab_size() const { 1023 // Returns size in words 1024 return ShenandoahHeapRegion::max_tlab_size_words(); 1025 } 1026 1027 class ShenandoahResizeGCLABClosure : public ThreadClosure { 1028 public: 1029 void do_thread(Thread* thread) { 1030 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 1031 thread->gclab().resize(); 1032 } 1033 }; 1034 1035 void ShenandoahHeap::resize_all_tlabs() { 1036 CollectedHeap::resize_all_tlabs(); 1037 1038 ShenandoahResizeGCLABClosure cl; 1039 Threads::java_threads_do(&cl); 1040 _workers->threads_do(&cl); 1041 } 1042 1043 class ShenandoahAccumulateStatisticsGCLABClosure : public ThreadClosure { 1044 public: 1045 void do_thread(Thread* thread) { 1046 assert(thread->gclab().is_initialized(), err_msg("GCLAB should be initialized for %s", thread->name())); 1047 thread->gclab().accumulate_statistics(); 1048 thread->gclab().initialize_statistics(); 1049 } 1050 }; 1051 1052 void ShenandoahHeap::accumulate_statistics_all_gclabs() { 1053 ShenandoahAccumulateStatisticsGCLABClosure cl; 1054 Threads::java_threads_do(&cl); 1055 _workers->threads_do(&cl); 1056 } 1057 1058 void ShenandoahHeap::collect(GCCause::Cause cause) { 1059 _control_thread->request_gc(cause); 1060 } 1061 1062 void ShenandoahHeap::do_full_collection(bool clear_all_soft_refs) { 1063 //assert(false, "Shouldn't need to do full collections"); 1064 } 1065 1066 CollectorPolicy* ShenandoahHeap::collector_policy() const { 1067 return _shenandoah_policy; 1068 } 1069 1070 void ShenandoahHeap::resize_tlabs() { 1071 CollectedHeap::resize_all_tlabs(); 1072 } 1073 1074 void ShenandoahHeap::accumulate_statistics_tlabs() { 1075 CollectedHeap::accumulate_statistics_all_tlabs(); 1076 } 1077 1078 HeapWord* ShenandoahHeap::block_start(const void* addr) const { 1079 Space* sp = heap_region_containing(addr); 1080 if (sp != NULL) { 1081 return sp->block_start(addr); 1082 } 1083 return NULL; 1084 } 1085 1086 size_t ShenandoahHeap::block_size(const HeapWord* addr) const { 1087 Space* sp = heap_region_containing(addr); 1088 assert(sp != NULL, "block_size of address outside of heap"); 1089 return sp->block_size(addr); 1090 } 1091 1092 bool ShenandoahHeap::block_is_obj(const HeapWord* addr) const { 1093 Space* sp = heap_region_containing(addr); 1094 return sp->block_is_obj(addr); 1095 } 1096 1097 jlong ShenandoahHeap::millis_since_last_gc() { 1098 double v = heuristics()->time_since_last_gc() * 1000; 1099 assert(0 <= v && v <= max_jlong, err_msg("value should fit: %f", v)); 1100 return (jlong)v; 1101 } 1102 1103 void ShenandoahHeap::prepare_for_verify() { 1104 if (SafepointSynchronize::is_at_safepoint()) { 1105 make_parsable(false); 1106 } 1107 } 1108 1109 void ShenandoahHeap::print_gc_threads_on(outputStream* st) const { 1110 workers()->print_worker_threads_on(st); 1111 if (ShenandoahStringDedup::is_enabled()) { 1112 ShenandoahStringDedup::print_worker_threads_on(st); 1113 } 1114 } 1115 1116 void ShenandoahHeap::gc_threads_do(ThreadClosure* tcl) const { 1117 workers()->threads_do(tcl); 1118 if (ShenandoahStringDedup::is_enabled()) { 1119 ShenandoahStringDedup::threads_do(tcl); 1120 } 1121 } 1122 1123 void ShenandoahHeap::print_tracing_info() const { 1124 if (PrintGC || TraceGen0Time || TraceGen1Time) { 1125 ResourceMark rm; 1126 outputStream* out = gclog_or_tty; 1127 phase_timings()->print_on(out); 1128 1129 out->cr(); 1130 out->cr(); 1131 1132 shenandoah_policy()->print_gc_stats(out); 1133 1134 out->cr(); 1135 out->cr(); 1136 1137 if (ShenandoahPacing) { 1138 pacer()->print_on(out); 1139 } 1140 1141 out->cr(); 1142 out->cr(); 1143 1144 if (ShenandoahAllocationTrace) { 1145 assert(alloc_tracker() != NULL, "Must be"); 1146 alloc_tracker()->print_on(out); 1147 } else { 1148 out->print_cr(" Allocation tracing is disabled, use -XX:+ShenandoahAllocationTrace to enable."); 1149 } 1150 } 1151 } 1152 1153 void ShenandoahHeap::verify(bool silent, VerifyOption vo) { 1154 if (ShenandoahSafepoint::is_at_shenandoah_safepoint() || ! UseTLAB) { 1155 if (ShenandoahVerify) { 1156 verifier()->verify_generic(vo); 1157 } else { 1158 // TODO: Consider allocating verification bitmaps on demand, 1159 // and turn this on unconditionally. 1160 } 1161 } 1162 } 1163 size_t ShenandoahHeap::tlab_capacity(Thread *thr) const { 1164 return _free_set->capacity(); 1165 } 1166 1167 class ObjectIterateScanRootClosure : public ExtendedOopClosure { 1168 private: 1169 MarkBitMap* _bitmap; 1170 Stack<oop,mtGC>* _oop_stack; 1171 1172 template <class T> 1173 void do_oop_work(T* p) { 1174 T o = oopDesc::load_heap_oop(p); 1175 if (!oopDesc::is_null(o)) { 1176 oop obj = oopDesc::decode_heap_oop_not_null(o); 1177 oop fwd = (oop) ShenandoahForwarding::get_forwardee_raw_unchecked(obj); 1178 if (fwd == NULL) { 1179 // There is an odd interaction with VM_HeapWalkOperation, see jvmtiTagMap.cpp. 1180 // 1181 // That operation walks the reachable objects on its own, storing the marking 1182 // wavefront in the object marks. When it is done, it calls the CollectedHeap 1183 // to iterate over all objects to clean up the mess. When it reaches here, 1184 // the Shenandoah fwdptr resolution code encounters the marked objects with 1185 // NULL forwardee. Trying to act on that would crash the VM. Or fail the 1186 // asserts, should we go for resolve_forwarded_pointer(obj). 1187 // 1188 // Therefore, we have to dodge it by doing the raw access to forwardee, and 1189 // assuming the object had no forwardee, if that thing is NULL. 1190 } else { 1191 obj = fwd; 1192 } 1193 assert(obj->is_oop(), "must be a valid oop"); 1194 if (!_bitmap->isMarked((HeapWord*) obj)) { 1195 _bitmap->mark((HeapWord*) obj); 1196 _oop_stack->push(obj); 1197 } 1198 } 1199 } 1200 public: 1201 ObjectIterateScanRootClosure(MarkBitMap* bitmap, Stack<oop,mtGC>* oop_stack) : 1202 _bitmap(bitmap), _oop_stack(oop_stack) {} 1203 void do_oop(oop* p) { do_oop_work(p); } 1204 void do_oop(narrowOop* p) { do_oop_work(p); } 1205 }; 1206 1207 /* 1208 * This is public API, used in preparation of object_iterate(). 1209 * Since we don't do linear scan of heap in object_iterate() (see comment below), we don't 1210 * need to make the heap parsable. For Shenandoah-internal linear heap scans that we can 1211 * control, we call SH::make_parsable(). 1212 */ 1213 void ShenandoahHeap::ensure_parsability(bool retire_tlabs) { 1214 // No-op. 1215 } 1216 1217 /* 1218 * Iterates objects in the heap. This is public API, used for, e.g., heap dumping. 1219 * 1220 * We cannot safely iterate objects by doing a linear scan at random points in time. Linear 1221 * scanning needs to deal with dead objects, which may have dead Klass* pointers (e.g. 1222 * calling oopDesc::size() would crash) or dangling reference fields (crashes) etc. Linear 1223 * scanning therefore depends on having a valid marking bitmap to support it. However, we only 1224 * have a valid marking bitmap after successful marking. In particular, we *don't* have a valid 1225 * marking bitmap during marking, after aborted marking or during/after cleanup (when we just 1226 * wiped the bitmap in preparation for next marking). 1227 * 1228 * For all those reasons, we implement object iteration as a single marking traversal, reporting 1229 * objects as we mark+traverse through the heap, starting from GC roots. JVMTI IterateThroughHeap 1230 * is allowed to report dead objects, but is not required to do so. 1231 */ 1232 void ShenandoahHeap::object_iterate(ObjectClosure* cl) { 1233 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1234 if (!_aux_bitmap_region_special && !os::commit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size(), false)) { 1235 log_warning(gc)("Could not commit native memory for auxiliary marking bitmap for heap iteration"); 1236 return; 1237 } 1238 1239 // Reset bitmap 1240 _aux_bit_map.clear(); 1241 1242 Stack<oop,mtGC> oop_stack; 1243 1244 // First, we process all GC roots. This populates the work stack with initial objects. 1245 ShenandoahRootProcessor rp(this, 1, ShenandoahPhaseTimings::_num_phases); 1246 ObjectIterateScanRootClosure oops(&_aux_bit_map, &oop_stack); 1247 CLDToOopClosure clds(&oops, false); 1248 CodeBlobToOopClosure blobs(&oops, false); 1249 rp.process_all_roots(&oops, &oops, &clds, &blobs, NULL, 0); 1250 1251 // Work through the oop stack to traverse heap. 1252 while (! oop_stack.is_empty()) { 1253 oop obj = oop_stack.pop(); 1254 assert(obj->is_oop(), "must be a valid oop"); 1255 cl->do_object(obj); 1256 obj->oop_iterate(&oops); 1257 } 1258 1259 assert(oop_stack.is_empty(), "should be empty"); 1260 1261 if (!_aux_bitmap_region_special && !os::uncommit_memory((char*)_aux_bitmap_region.start(), _aux_bitmap_region.byte_size())) { 1262 log_warning(gc)("Could not uncommit native memory for auxiliary marking bitmap for heap iteration"); 1263 } 1264 } 1265 1266 void ShenandoahHeap::safe_object_iterate(ObjectClosure* cl) { 1267 assert(SafepointSynchronize::is_at_safepoint(), "safe iteration is only available during safepoints"); 1268 object_iterate(cl); 1269 } 1270 1271 void ShenandoahHeap::oop_iterate(ExtendedOopClosure* cl) { 1272 ObjectToOopClosure cl2(cl); 1273 object_iterate(&cl2); 1274 } 1275 1276 class ShenandoahSpaceClosureRegionClosure: public ShenandoahHeapRegionClosure { 1277 SpaceClosure* _cl; 1278 public: 1279 ShenandoahSpaceClosureRegionClosure(SpaceClosure* cl) : _cl(cl) {} 1280 void heap_region_do(ShenandoahHeapRegion* r) { 1281 _cl->do_space(r); 1282 } 1283 }; 1284 1285 void ShenandoahHeap::space_iterate(SpaceClosure* cl) { 1286 ShenandoahSpaceClosureRegionClosure blk(cl); 1287 heap_region_iterate(&blk); 1288 } 1289 1290 Space* ShenandoahHeap::space_containing(const void* oop) const { 1291 Space* res = heap_region_containing(oop); 1292 return res; 1293 } 1294 1295 void ShenandoahHeap::gc_prologue(bool b) { 1296 Unimplemented(); 1297 } 1298 1299 void ShenandoahHeap::gc_epilogue(bool b) { 1300 Unimplemented(); 1301 } 1302 1303 void ShenandoahHeap::heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1304 for (size_t i = 0; i < num_regions(); i++) { 1305 ShenandoahHeapRegion* current = get_region(i); 1306 blk->heap_region_do(current); 1307 } 1308 } 1309 1310 class ShenandoahParallelHeapRegionTask : public AbstractGangTask { 1311 private: 1312 ShenandoahHeap* const _heap; 1313 ShenandoahHeapRegionClosure* const _blk; 1314 1315 char _pad0[DEFAULT_CACHE_LINE_SIZE]; 1316 volatile jint _index; 1317 char _pad1[DEFAULT_CACHE_LINE_SIZE]; 1318 1319 public: 1320 ShenandoahParallelHeapRegionTask(ShenandoahHeapRegionClosure* blk) : 1321 AbstractGangTask("Parallel Region Task"), 1322 _heap(ShenandoahHeap::heap()), _blk(blk), _index(0) {} 1323 1324 void work(uint worker_id) { 1325 jint stride = (jint)ShenandoahParallelRegionStride; 1326 1327 jint max = (jint)_heap->num_regions(); 1328 while (_index < max) { 1329 jint cur = Atomic::add(stride, &_index) - stride; 1330 jint start = cur; 1331 jint end = MIN2(cur + stride, max); 1332 if (start >= max) break; 1333 1334 for (jint i = cur; i < end; i++) { 1335 ShenandoahHeapRegion* current = _heap->get_region((size_t)i); 1336 _blk->heap_region_do(current); 1337 } 1338 } 1339 } 1340 }; 1341 1342 void ShenandoahHeap::parallel_heap_region_iterate(ShenandoahHeapRegionClosure* blk) const { 1343 assert(blk->is_thread_safe(), "Only thread-safe closures here"); 1344 if (num_regions() > ShenandoahParallelRegionStride) { 1345 ShenandoahParallelHeapRegionTask task(blk); 1346 workers()->run_task(&task); 1347 } else { 1348 heap_region_iterate(blk); 1349 } 1350 } 1351 1352 class ShenandoahClearLivenessClosure : public ShenandoahHeapRegionClosure { 1353 private: 1354 ShenandoahMarkingContext* const _ctx; 1355 public: 1356 ShenandoahClearLivenessClosure() : _ctx(ShenandoahHeap::heap()->marking_context()) {} 1357 1358 void heap_region_do(ShenandoahHeapRegion* r) { 1359 if (r->is_active()) { 1360 r->clear_live_data(); 1361 _ctx->capture_top_at_mark_start(r); 1362 } else { 1363 assert(!r->has_live(), 1364 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number())); 1365 assert(_ctx->top_at_mark_start(r) == r->top(), 1366 err_msg("Region " SIZE_FORMAT " should already have correct TAMS", r->region_number())); 1367 } 1368 } 1369 1370 bool is_thread_safe() { return true; } 1371 }; 1372 1373 void ShenandoahHeap::op_init_mark() { 1374 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1375 assert(Thread::current()->is_VM_thread(), "can only do this in VMThread"); 1376 1377 assert(marking_context()->is_bitmap_clear(), "need clear marking bitmap"); 1378 assert(!marking_context()->is_complete(), "should not be complete"); 1379 1380 if (ShenandoahVerify) { 1381 verifier()->verify_before_concmark(); 1382 } 1383 1384 { 1385 ShenandoahGCPhase phase(ShenandoahPhaseTimings::accumulate_stats); 1386 accumulate_statistics_tlabs(); 1387 } 1388 1389 if (VerifyBeforeGC) { 1390 Universe::verify(); 1391 } 1392 1393 set_concurrent_mark_in_progress(true); 1394 // We need to reset all TLABs because we'd lose marks on all objects allocated in them. 1395 if (UseTLAB) { 1396 ShenandoahGCPhase phase(ShenandoahPhaseTimings::make_parsable); 1397 make_parsable(true); 1398 } 1399 1400 { 1401 ShenandoahGCPhase phase(ShenandoahPhaseTimings::clear_liveness); 1402 ShenandoahClearLivenessClosure clc; 1403 parallel_heap_region_iterate(&clc); 1404 } 1405 1406 // Make above changes visible to worker threads 1407 OrderAccess::fence(); 1408 1409 concurrent_mark()->mark_roots(ShenandoahPhaseTimings::scan_roots); 1410 1411 if (UseTLAB) { 1412 ShenandoahGCPhase phase(ShenandoahPhaseTimings::resize_tlabs); 1413 resize_tlabs(); 1414 } 1415 1416 if (ShenandoahPacing) { 1417 pacer()->setup_for_mark(); 1418 } 1419 } 1420 1421 void ShenandoahHeap::op_mark() { 1422 concurrent_mark()->mark_from_roots(); 1423 } 1424 1425 class ShenandoahCompleteLivenessClosure : public ShenandoahHeapRegionClosure { 1426 private: 1427 ShenandoahMarkingContext* const _ctx; 1428 public: 1429 ShenandoahCompleteLivenessClosure() : _ctx(ShenandoahHeap::heap()->complete_marking_context()) {} 1430 1431 void heap_region_do(ShenandoahHeapRegion* r) { 1432 if (r->is_active()) { 1433 HeapWord *tams = _ctx->top_at_mark_start(r); 1434 HeapWord *top = r->top(); 1435 if (top > tams) { 1436 r->increase_live_data_alloc_words(pointer_delta(top, tams)); 1437 } 1438 } else { 1439 assert(!r->has_live(), 1440 err_msg("Region " SIZE_FORMAT " should have no live data", r->region_number())); 1441 assert(_ctx->top_at_mark_start(r) == r->top(), 1442 err_msg("Region " SIZE_FORMAT " should have correct TAMS", r->region_number())); 1443 } 1444 } 1445 1446 bool is_thread_safe() { return true; } 1447 }; 1448 1449 void ShenandoahHeap::op_final_mark() { 1450 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1451 1452 // It is critical that we 1453 // evacuate roots right after finishing marking, so that we don't 1454 // get unmarked objects in the roots. 1455 1456 if (!cancelled_gc()) { 1457 concurrent_mark()->finish_mark_from_roots(/* full_gc = */ false); 1458 1459 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->reset_taskqueue_stats()); 1460 1461 if (has_forwarded_objects()) { 1462 concurrent_mark()->update_roots(ShenandoahPhaseTimings::update_roots); 1463 } 1464 1465 TASKQUEUE_STATS_ONLY(concurrent_mark()->task_queues()->print_taskqueue_stats()); 1466 1467 stop_concurrent_marking(); 1468 1469 // All allocations past TAMS are implicitly live, adjust the region data. 1470 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap. 1471 { 1472 ShenandoahGCPhase phase(ShenandoahPhaseTimings::complete_liveness); 1473 ShenandoahCompleteLivenessClosure cl; 1474 parallel_heap_region_iterate(&cl); 1475 } 1476 1477 // Force the threads to reacquire their TLABs outside the collection set. 1478 { 1479 ShenandoahGCPhase phase(ShenandoahPhaseTimings::retire_tlabs); 1480 make_parsable(true); 1481 } 1482 1483 // We are about to select the collection set, make sure it knows about 1484 // current pinning status. Also, this allows trashing more regions that 1485 // now have their pinning status dropped. 1486 { 1487 ShenandoahGCPhase phase(ShenandoahPhaseTimings::sync_pinned); 1488 sync_pinned_region_status(); 1489 } 1490 1491 // Trash the collection set left over from previous cycle, if any. 1492 { 1493 ShenandoahGCPhase phase(ShenandoahPhaseTimings::trash_cset); 1494 trash_cset_regions(); 1495 } 1496 1497 { 1498 ShenandoahGCPhase prepare_evac(ShenandoahPhaseTimings::prepare_evac); 1499 1500 ShenandoahHeapLocker locker(lock()); 1501 _collection_set->clear(); 1502 _free_set->clear(); 1503 1504 heuristics()->choose_collection_set(_collection_set); 1505 _free_set->rebuild(); 1506 } 1507 1508 // If collection set has candidates, start evacuation. 1509 // Otherwise, bypass the rest of the cycle. 1510 if (!collection_set()->is_empty()) { 1511 ShenandoahGCPhase init_evac(ShenandoahPhaseTimings::init_evac); 1512 1513 if (ShenandoahVerify) { 1514 verifier()->verify_before_evacuation(); 1515 } 1516 1517 set_evacuation_in_progress(true); 1518 // From here on, we need to update references. 1519 set_has_forwarded_objects(true); 1520 1521 evacuate_and_update_roots(); 1522 1523 if (ShenandoahPacing) { 1524 pacer()->setup_for_evac(); 1525 } 1526 1527 if (ShenandoahVerify) { 1528 verifier()->verify_during_evacuation(); 1529 } 1530 } else { 1531 if (ShenandoahVerify) { 1532 verifier()->verify_after_concmark(); 1533 } 1534 1535 if (VerifyAfterGC) { 1536 Universe::verify(); 1537 } 1538 } 1539 1540 } else { 1541 concurrent_mark()->cancel(); 1542 stop_concurrent_marking(); 1543 1544 if (process_references()) { 1545 // Abandon reference processing right away: pre-cleaning must have failed. 1546 ReferenceProcessor *rp = ref_processor(); 1547 rp->disable_discovery(); 1548 rp->abandon_partial_discovery(); 1549 rp->verify_no_references_recorded(); 1550 } 1551 } 1552 } 1553 1554 void ShenandoahHeap::op_final_evac() { 1555 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should be at safepoint"); 1556 1557 set_evacuation_in_progress(false); 1558 if (ShenandoahVerify) { 1559 verifier()->verify_after_evacuation(); 1560 } 1561 1562 if (VerifyAfterGC) { 1563 Universe::verify(); 1564 } 1565 } 1566 1567 void ShenandoahHeap::op_conc_evac() { 1568 ShenandoahEvacuationTask task(this, _collection_set, true); 1569 workers()->run_task(&task); 1570 } 1571 1572 void ShenandoahHeap::op_stw_evac() { 1573 ShenandoahEvacuationTask task(this, _collection_set, false); 1574 workers()->run_task(&task); 1575 } 1576 1577 void ShenandoahHeap::op_updaterefs() { 1578 update_heap_references(true); 1579 } 1580 1581 void ShenandoahHeap::op_cleanup() { 1582 free_set()->recycle_trash(); 1583 } 1584 1585 void ShenandoahHeap::op_reset() { 1586 reset_mark_bitmap(); 1587 } 1588 1589 void ShenandoahHeap::op_preclean() { 1590 concurrent_mark()->preclean_weak_refs(); 1591 } 1592 1593 void ShenandoahHeap::op_init_traversal() { 1594 traversal_gc()->init_traversal_collection(); 1595 } 1596 1597 void ShenandoahHeap::op_traversal() { 1598 traversal_gc()->concurrent_traversal_collection(); 1599 } 1600 1601 void ShenandoahHeap::op_final_traversal() { 1602 traversal_gc()->final_traversal_collection(); 1603 } 1604 1605 void ShenandoahHeap::op_full(GCCause::Cause cause) { 1606 ShenandoahMetricsSnapshot metrics; 1607 metrics.snap_before(); 1608 1609 full_gc()->do_it(cause); 1610 1611 metrics.snap_after(); 1612 1613 if (metrics.is_good_progress()) { 1614 _progress_last_gc.set(); 1615 } else { 1616 // Nothing to do. Tell the allocation path that we have failed to make 1617 // progress, and it can finally fail. 1618 _progress_last_gc.unset(); 1619 } 1620 } 1621 1622 void ShenandoahHeap::op_degenerated(ShenandoahDegenPoint point) { 1623 // Degenerated GC is STW, but it can also fail. Current mechanics communicates 1624 // GC failure via cancelled_concgc() flag. So, if we detect the failure after 1625 // some phase, we have to upgrade the Degenerate GC to Full GC. 1626 1627 clear_cancelled_gc(); 1628 1629 ShenandoahMetricsSnapshot metrics; 1630 metrics.snap_before(); 1631 1632 switch (point) { 1633 case _degenerated_traversal: 1634 { 1635 // Drop the collection set. Note: this leaves some already forwarded objects 1636 // behind, which may be problematic, see comments for ShenandoahEvacAssist 1637 // workarounds in ShenandoahTraversalHeuristics. 1638 1639 ShenandoahHeapLocker locker(lock()); 1640 collection_set()->clear_current_index(); 1641 for (size_t i = 0; i < collection_set()->count(); i++) { 1642 ShenandoahHeapRegion* r = collection_set()->next(); 1643 r->make_regular_bypass(); 1644 } 1645 collection_set()->clear(); 1646 } 1647 op_final_traversal(); 1648 op_cleanup(); 1649 return; 1650 1651 // The cases below form the Duff's-like device: it describes the actual GC cycle, 1652 // but enters it at different points, depending on which concurrent phase had 1653 // degenerated. 1654 1655 case _degenerated_outside_cycle: 1656 // We have degenerated from outside the cycle, which means something is bad with 1657 // the heap, most probably heavy humongous fragmentation, or we are very low on free 1658 // space. It makes little sense to wait for Full GC to reclaim as much as it can, when 1659 // we can do the most aggressive degen cycle, which includes processing references and 1660 // class unloading, unless those features are explicitly disabled. 1661 // 1662 // Note that we can only do this for "outside-cycle" degens, otherwise we would risk 1663 // changing the cycle parameters mid-cycle during concurrent -> degenerated handover. 1664 set_process_references(heuristics()->can_process_references()); 1665 set_unload_classes(heuristics()->can_unload_classes()); 1666 1667 if (is_traversal_mode()) { 1668 // Not possible to degenerate from here, upgrade to Full GC right away. 1669 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1670 op_degenerated_fail(); 1671 return; 1672 } 1673 1674 op_reset(); 1675 1676 op_init_mark(); 1677 if (cancelled_gc()) { 1678 op_degenerated_fail(); 1679 return; 1680 } 1681 1682 case _degenerated_mark: 1683 op_final_mark(); 1684 if (cancelled_gc()) { 1685 op_degenerated_fail(); 1686 return; 1687 } 1688 1689 op_cleanup(); 1690 1691 case _degenerated_evac: 1692 // If heuristics thinks we should do the cycle, this flag would be set, 1693 // and we can do evacuation. Otherwise, it would be the shortcut cycle. 1694 if (is_evacuation_in_progress()) { 1695 1696 // Degeneration under oom-evac protocol might have left some objects in 1697 // collection set un-evacuated. Restart evacuation from the beginning to 1698 // capture all objects. For all the objects that are already evacuated, 1699 // it would be a simple check, which is supposed to be fast. This is also 1700 // safe to do even without degeneration, as CSet iterator is at beginning 1701 // in preparation for evacuation anyway. 1702 // 1703 // Before doing that, we need to make sure we never had any cset-pinned 1704 // regions. This may happen if allocation failure happened when evacuating 1705 // the about-to-be-pinned object, oom-evac protocol left the object in 1706 // the collection set, and then the pin reached the cset region. If we continue 1707 // the cycle here, we would trash the cset and alive objects in it. To avoid 1708 // it, we fail degeneration right away and slide into Full GC to recover. 1709 1710 { 1711 sync_pinned_region_status(); 1712 collection_set()->clear_current_index(); 1713 1714 ShenandoahHeapRegion* r; 1715 while ((r = collection_set()->next()) != NULL) { 1716 if (r->is_pinned()) { 1717 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1718 op_degenerated_fail(); 1719 return; 1720 } 1721 } 1722 1723 collection_set()->clear_current_index(); 1724 } 1725 1726 op_stw_evac(); 1727 if (cancelled_gc()) { 1728 op_degenerated_fail(); 1729 return; 1730 } 1731 } 1732 1733 // If heuristics thinks we should do the cycle, this flag would be set, 1734 // and we need to do update-refs. Otherwise, it would be the shortcut cycle. 1735 if (has_forwarded_objects()) { 1736 op_init_updaterefs(); 1737 if (cancelled_gc()) { 1738 op_degenerated_fail(); 1739 return; 1740 } 1741 } 1742 1743 case _degenerated_updaterefs: 1744 if (has_forwarded_objects()) { 1745 op_final_updaterefs(); 1746 if (cancelled_gc()) { 1747 op_degenerated_fail(); 1748 return; 1749 } 1750 } 1751 1752 op_cleanup(); 1753 break; 1754 1755 default: 1756 ShouldNotReachHere(); 1757 } 1758 1759 if (ShenandoahVerify) { 1760 verifier()->verify_after_degenerated(); 1761 } 1762 1763 if (VerifyAfterGC) { 1764 Universe::verify(); 1765 } 1766 1767 metrics.snap_after(); 1768 1769 // Check for futility and fail. There is no reason to do several back-to-back Degenerated cycles, 1770 // because that probably means the heap is overloaded and/or fragmented. 1771 if (!metrics.is_good_progress()) { 1772 _progress_last_gc.unset(); 1773 cancel_gc(GCCause::_shenandoah_upgrade_to_full_gc); 1774 op_degenerated_futile(); 1775 } else { 1776 _progress_last_gc.set(); 1777 } 1778 } 1779 1780 void ShenandoahHeap::op_degenerated_fail() { 1781 log_info(gc)("Cannot finish degeneration, upgrading to Full GC"); 1782 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1783 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1784 } 1785 1786 void ShenandoahHeap::op_degenerated_futile() { 1787 shenandoah_policy()->record_degenerated_upgrade_to_full(); 1788 op_full(GCCause::_shenandoah_upgrade_to_full_gc); 1789 } 1790 1791 void ShenandoahHeap::stop_concurrent_marking() { 1792 assert(is_concurrent_mark_in_progress(), "How else could we get here?"); 1793 if (!cancelled_gc()) { 1794 // If we needed to update refs, and concurrent marking has been cancelled, 1795 // we need to finish updating references. 1796 set_has_forwarded_objects(false); 1797 mark_complete_marking_context(); 1798 } 1799 set_concurrent_mark_in_progress(false); 1800 } 1801 1802 void ShenandoahHeap::force_satb_flush_all_threads() { 1803 if (!is_concurrent_mark_in_progress() && !is_concurrent_traversal_in_progress()) { 1804 // No need to flush SATBs 1805 return; 1806 } 1807 1808 // Do not block if Threads lock is busy. This avoids the potential deadlock 1809 // when this code is called from the periodic task, and something else is 1810 // expecting the periodic task to complete without blocking. On the off-chance 1811 // Threads lock is busy momentarily, try to acquire several times. 1812 for (int t = 0; t < 10; t++) { 1813 if (Threads_lock->try_lock()) { 1814 JavaThread::set_force_satb_flush_all_threads(true); 1815 Threads_lock->unlock(); 1816 1817 // The threads are not "acquiring" their thread-local data, but it does not 1818 // hurt to "release" the updates here anyway. 1819 OrderAccess::fence(); 1820 break; 1821 } 1822 os::naked_short_sleep(1); 1823 } 1824 } 1825 1826 void ShenandoahHeap::set_gc_state_mask(uint mask, bool value) { 1827 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Should really be Shenandoah safepoint"); 1828 _gc_state.set_cond(mask, value); 1829 JavaThread::set_gc_state_all_threads(_gc_state.raw_value()); 1830 } 1831 1832 void ShenandoahHeap::set_concurrent_mark_in_progress(bool in_progress) { 1833 set_gc_state_mask(MARKING, in_progress); 1834 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1835 } 1836 1837 void ShenandoahHeap::set_concurrent_traversal_in_progress(bool in_progress) { 1838 set_gc_state_mask(TRAVERSAL | HAS_FORWARDED | UPDATEREFS, in_progress); 1839 JavaThread::satb_mark_queue_set().set_active_all_threads(in_progress, !in_progress); 1840 } 1841 1842 void ShenandoahHeap::set_evacuation_in_progress(bool in_progress) { 1843 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "Only call this at safepoint"); 1844 set_gc_state_mask(EVACUATION, in_progress); 1845 } 1846 1847 void ShenandoahHeap::ref_processing_init() { 1848 MemRegion mr = reserved_region(); 1849 1850 assert(_max_workers > 0, "Sanity"); 1851 1852 _ref_processor = 1853 new ReferenceProcessor(mr, // span 1854 ParallelRefProcEnabled, // MT processing 1855 _max_workers, // Degree of MT processing 1856 true, // MT discovery 1857 _max_workers, // Degree of MT discovery 1858 false, // Reference discovery is not atomic 1859 NULL); // No closure, should be installed before use 1860 1861 shenandoah_assert_rp_isalive_not_installed(); 1862 } 1863 1864 void ShenandoahHeap::acquire_pending_refs_lock() { 1865 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::acquirePLL); 1866 } 1867 1868 void ShenandoahHeap::release_pending_refs_lock() { 1869 _control_thread->slt()->manipulatePLL(SurrogateLockerThread::releaseAndNotifyPLL); 1870 } 1871 1872 GCTracer* ShenandoahHeap::tracer() { 1873 return shenandoah_policy()->tracer(); 1874 } 1875 1876 size_t ShenandoahHeap::tlab_used(Thread* thread) const { 1877 return _free_set->used(); 1878 } 1879 1880 void ShenandoahHeap::cancel_gc(GCCause::Cause cause) { 1881 if (try_cancel_gc()) { 1882 FormatBuffer<> msg("Cancelling GC: %s", GCCause::to_string(cause)); 1883 log_info(gc)("%s", msg.buffer()); 1884 Events::log(Thread::current(), "%s", msg.buffer()); 1885 } 1886 } 1887 1888 uint ShenandoahHeap::max_workers() { 1889 return _max_workers; 1890 } 1891 1892 void ShenandoahHeap::stop() { 1893 // The shutdown sequence should be able to terminate when GC is running. 1894 1895 // Step 0. Notify policy to disable event recording. 1896 _shenandoah_policy->record_shutdown(); 1897 1898 // Step 1. Notify control thread that we are in shutdown. 1899 // Note that we cannot do that with stop(), because stop() is blocking and waits for the actual shutdown. 1900 // Doing stop() here would wait for the normal GC cycle to complete, never falling through to cancel below. 1901 _control_thread->prepare_for_graceful_shutdown(); 1902 1903 // Step 2. Notify GC workers that we are cancelling GC. 1904 cancel_gc(GCCause::_shenandoah_stop_vm); 1905 1906 // Step 3. Wait until GC worker exits normally. 1907 _control_thread->stop(); 1908 1909 // Step 4. Stop String Dedup thread if it is active 1910 if (ShenandoahStringDedup::is_enabled()) { 1911 ShenandoahStringDedup::stop(); 1912 } 1913 } 1914 1915 void ShenandoahHeap::unload_classes_and_cleanup_tables(bool full_gc) { 1916 assert(heuristics()->can_unload_classes(), "Class unloading should be enabled"); 1917 1918 ShenandoahGCPhase root_phase(full_gc ? 1919 ShenandoahPhaseTimings::full_gc_purge : 1920 ShenandoahPhaseTimings::purge); 1921 1922 ShenandoahIsAliveSelector alive; 1923 BoolObjectClosure* is_alive = alive.is_alive_closure(); 1924 1925 bool purged_class; 1926 1927 // Unload classes and purge SystemDictionary. 1928 { 1929 ShenandoahGCPhase phase(full_gc ? 1930 ShenandoahPhaseTimings::full_gc_purge_class_unload : 1931 ShenandoahPhaseTimings::purge_class_unload); 1932 purged_class = SystemDictionary::do_unloading(is_alive, 1933 full_gc /* do_cleaning*/ ); 1934 } 1935 1936 { 1937 ShenandoahGCPhase phase(full_gc ? 1938 ShenandoahPhaseTimings::full_gc_purge_par : 1939 ShenandoahPhaseTimings::purge_par); 1940 uint active = _workers->active_workers(); 1941 ParallelCleaningTask unlink_task(is_alive, true, true, active, purged_class); 1942 _workers->run_task(&unlink_task); 1943 } 1944 1945 if (ShenandoahStringDedup::is_enabled()) { 1946 ShenandoahGCPhase phase(full_gc ? 1947 ShenandoahPhaseTimings::full_gc_purge_string_dedup : 1948 ShenandoahPhaseTimings::purge_string_dedup); 1949 ShenandoahStringDedup::parallel_cleanup(); 1950 } 1951 1952 { 1953 ShenandoahGCPhase phase(full_gc ? 1954 ShenandoahPhaseTimings::full_gc_purge_cldg : 1955 ShenandoahPhaseTimings::purge_cldg); 1956 ClassLoaderDataGraph::purge(); 1957 } 1958 } 1959 1960 void ShenandoahHeap::set_has_forwarded_objects(bool cond) { 1961 set_gc_state_mask(HAS_FORWARDED, cond); 1962 } 1963 1964 void ShenandoahHeap::set_process_references(bool pr) { 1965 _process_references.set_cond(pr); 1966 } 1967 1968 void ShenandoahHeap::set_unload_classes(bool uc) { 1969 _unload_classes.set_cond(uc); 1970 } 1971 1972 bool ShenandoahHeap::process_references() const { 1973 return _process_references.is_set(); 1974 } 1975 1976 bool ShenandoahHeap::unload_classes() const { 1977 return _unload_classes.is_set(); 1978 } 1979 1980 address ShenandoahHeap::in_cset_fast_test_addr() { 1981 ShenandoahHeap* heap = ShenandoahHeap::heap(); 1982 assert(heap->collection_set() != NULL, "Sanity"); 1983 return (address) heap->collection_set()->biased_map_address(); 1984 } 1985 1986 address ShenandoahHeap::cancelled_gc_addr() { 1987 return (address) ShenandoahHeap::heap()->_cancelled_gc.addr_of(); 1988 } 1989 1990 address ShenandoahHeap::gc_state_addr() { 1991 return (address) ShenandoahHeap::heap()->_gc_state.addr_of(); 1992 } 1993 1994 size_t ShenandoahHeap::conservative_max_heap_alignment() { 1995 size_t align = ShenandoahMaxRegionSize; 1996 if (UseLargePages) { 1997 align = MAX2(align, os::large_page_size()); 1998 } 1999 return align; 2000 } 2001 2002 size_t ShenandoahHeap::bytes_allocated_since_gc_start() { 2003 return OrderAccess::load_acquire(&_bytes_allocated_since_gc_start); 2004 } 2005 2006 void ShenandoahHeap::reset_bytes_allocated_since_gc_start() { 2007 OrderAccess::release_store_fence(&_bytes_allocated_since_gc_start, (size_t)0); 2008 } 2009 2010 void ShenandoahHeap::set_degenerated_gc_in_progress(bool in_progress) { 2011 _degenerated_gc_in_progress.set_cond(in_progress); 2012 } 2013 2014 void ShenandoahHeap::set_full_gc_in_progress(bool in_progress) { 2015 _full_gc_in_progress.set_cond(in_progress); 2016 } 2017 2018 void ShenandoahHeap::set_full_gc_move_in_progress(bool in_progress) { 2019 assert (is_full_gc_in_progress(), "should be"); 2020 _full_gc_move_in_progress.set_cond(in_progress); 2021 } 2022 2023 void ShenandoahHeap::set_update_refs_in_progress(bool in_progress) { 2024 set_gc_state_mask(UPDATEREFS, in_progress); 2025 } 2026 2027 void ShenandoahHeap::register_nmethod(nmethod* nm) { 2028 ShenandoahCodeRoots::add_nmethod(nm); 2029 } 2030 2031 void ShenandoahHeap::unregister_nmethod(nmethod* nm) { 2032 ShenandoahCodeRoots::remove_nmethod(nm); 2033 } 2034 2035 oop ShenandoahHeap::pin_object(JavaThread* thr, oop o) { 2036 heap_region_containing(o)->record_pin(); 2037 return o; 2038 } 2039 2040 void ShenandoahHeap::unpin_object(JavaThread* thr, oop o) { 2041 heap_region_containing(o)->record_unpin(); 2042 } 2043 2044 void ShenandoahHeap::sync_pinned_region_status() { 2045 ShenandoahHeapLocker locker(lock()); 2046 2047 for (size_t i = 0; i < num_regions(); i++) { 2048 ShenandoahHeapRegion *r = get_region(i); 2049 if (r->is_active()) { 2050 if (r->is_pinned()) { 2051 if (r->pin_count() == 0) { 2052 r->make_unpinned(); 2053 } 2054 } else { 2055 if (r->pin_count() > 0) { 2056 r->make_pinned(); 2057 } 2058 } 2059 } 2060 } 2061 2062 assert_pinned_region_status(); 2063 } 2064 2065 #ifdef ASSERT 2066 void ShenandoahHeap::assert_pinned_region_status() { 2067 for (size_t i = 0; i < num_regions(); i++) { 2068 ShenandoahHeapRegion* r = get_region(i); 2069 assert((r->is_pinned() && r->pin_count() > 0) || (!r->is_pinned() && r->pin_count() == 0), 2070 err_msg("Region " SIZE_FORMAT " pinning status is inconsistent", i)); 2071 } 2072 } 2073 #endif 2074 2075 GCTimer* ShenandoahHeap::gc_timer() const { 2076 return _gc_timer; 2077 } 2078 2079 #ifdef ASSERT 2080 void ShenandoahHeap::assert_gc_workers(uint nworkers) { 2081 assert(nworkers > 0 && nworkers <= max_workers(), "Sanity"); 2082 2083 if (ShenandoahSafepoint::is_at_shenandoah_safepoint()) { 2084 if (UseDynamicNumberOfGCThreads || 2085 (FLAG_IS_DEFAULT(ParallelGCThreads) && ForceDynamicNumberOfGCThreads)) { 2086 assert(nworkers <= ParallelGCThreads, "Cannot use more than it has"); 2087 } else { 2088 // Use ParallelGCThreads inside safepoints 2089 assert(nworkers == ParallelGCThreads, "Use ParalleGCThreads within safepoints"); 2090 } 2091 } else { 2092 if (UseDynamicNumberOfGCThreads || 2093 (FLAG_IS_DEFAULT(ConcGCThreads) && ForceDynamicNumberOfGCThreads)) { 2094 assert(nworkers <= ConcGCThreads, "Cannot use more than it has"); 2095 } else { 2096 // Use ConcGCThreads outside safepoints 2097 assert(nworkers == ConcGCThreads, "Use ConcGCThreads outside safepoints"); 2098 } 2099 } 2100 } 2101 #endif 2102 2103 ShenandoahVerifier* ShenandoahHeap::verifier() { 2104 guarantee(ShenandoahVerify, "Should be enabled"); 2105 assert (_verifier != NULL, "sanity"); 2106 return _verifier; 2107 } 2108 2109 ShenandoahUpdateHeapRefsClosure::ShenandoahUpdateHeapRefsClosure() : 2110 _heap(ShenandoahHeap::heap()) {} 2111 2112 class ShenandoahUpdateHeapRefsTask : public AbstractGangTask { 2113 private: 2114 ShenandoahHeap* _heap; 2115 ShenandoahRegionIterator* _regions; 2116 bool _concurrent; 2117 2118 public: 2119 ShenandoahUpdateHeapRefsTask(ShenandoahRegionIterator* regions, bool concurrent) : 2120 AbstractGangTask("Concurrent Update References Task"), 2121 _heap(ShenandoahHeap::heap()), 2122 _regions(regions), 2123 _concurrent(concurrent) { 2124 } 2125 2126 void work(uint worker_id) { 2127 ShenandoahConcurrentWorkerSession worker_session(worker_id); 2128 ShenandoahUpdateHeapRefsClosure cl; 2129 ShenandoahHeapRegion* r = _regions->next(); 2130 ShenandoahMarkingContext* const ctx = _heap->complete_marking_context(); 2131 while (r != NULL) { 2132 HeapWord* top_at_start_ur = r->concurrent_iteration_safe_limit(); 2133 assert (top_at_start_ur >= r->bottom(), "sanity"); 2134 if (r->is_active() && !r->is_cset()) { 2135 _heap->marked_object_oop_iterate(r, &cl, top_at_start_ur); 2136 } 2137 if (ShenandoahPacing) { 2138 _heap->pacer()->report_updaterefs(pointer_delta(top_at_start_ur, r->bottom())); 2139 } 2140 if (_heap->cancelled_gc()) { 2141 return; 2142 } 2143 r = _regions->next(); 2144 } 2145 } 2146 }; 2147 2148 void ShenandoahHeap::update_heap_references(bool concurrent) { 2149 ShenandoahUpdateHeapRefsTask task(&_update_refs_iterator, concurrent); 2150 workers()->run_task(&task); 2151 } 2152 2153 void ShenandoahHeap::op_init_updaterefs() { 2154 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2155 2156 set_evacuation_in_progress(false); 2157 2158 if (ShenandoahVerify) { 2159 verifier()->verify_before_updaterefs(); 2160 } 2161 2162 set_update_refs_in_progress(true); 2163 2164 { 2165 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_prepare); 2166 2167 make_parsable(true); 2168 for (uint i = 0; i < num_regions(); i++) { 2169 ShenandoahHeapRegion* r = get_region(i); 2170 r->set_concurrent_iteration_safe_limit(r->top()); 2171 } 2172 2173 // Reset iterator. 2174 _update_refs_iterator.reset(); 2175 } 2176 2177 if (ShenandoahPacing) { 2178 pacer()->setup_for_updaterefs(); 2179 } 2180 } 2181 2182 void ShenandoahHeap::op_final_updaterefs() { 2183 assert(ShenandoahSafepoint::is_at_shenandoah_safepoint(), "must be at safepoint"); 2184 2185 // Check if there is left-over work, and finish it 2186 if (_update_refs_iterator.has_next()) { 2187 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_finish_work); 2188 2189 // Finish updating references where we left off. 2190 clear_cancelled_gc(); 2191 update_heap_references(false); 2192 } 2193 2194 // Clear cancelled GC, if set. On cancellation path, the block before would handle 2195 // everything. On degenerated paths, cancelled gc would not be set anyway. 2196 if (cancelled_gc()) { 2197 clear_cancelled_gc(); 2198 } 2199 assert(!cancelled_gc(), "Should have been done right before"); 2200 2201 concurrent_mark()->update_roots(is_degenerated_gc_in_progress() ? 2202 ShenandoahPhaseTimings::degen_gc_update_roots: 2203 ShenandoahPhaseTimings::final_update_refs_roots); 2204 2205 { 2206 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_trash_cset); 2207 trash_cset_regions(); 2208 } 2209 2210 set_has_forwarded_objects(false); 2211 set_update_refs_in_progress(false); 2212 2213 if (ShenandoahVerify) { 2214 verifier()->verify_after_updaterefs(); 2215 } 2216 2217 if (VerifyAfterGC) { 2218 Universe::verify(); 2219 } 2220 2221 // Drop unnecessary "pinned" state from regions that does not have CP marks 2222 // anymore, as this would allow trashing them below. 2223 { 2224 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_sync_pinned); 2225 sync_pinned_region_status(); 2226 } 2227 2228 { 2229 ShenandoahHeapLocker locker(lock()); 2230 _free_set->rebuild(); 2231 } 2232 } 2233 2234 #ifdef ASSERT 2235 void ShenandoahHeap::assert_heaplock_not_owned_by_current_thread() { 2236 _lock.assert_not_owned_by_current_thread(); 2237 } 2238 2239 void ShenandoahHeap::assert_heaplock_owned_by_current_thread() { 2240 _lock.assert_owned_by_current_thread(); 2241 } 2242 2243 void ShenandoahHeap::assert_heaplock_or_safepoint() { 2244 _lock.assert_owned_by_current_thread_or_safepoint(); 2245 } 2246 #endif 2247 2248 void ShenandoahHeap::print_extended_on(outputStream *st) const { 2249 print_on(st); 2250 print_heap_regions_on(st); 2251 } 2252 2253 bool ShenandoahHeap::is_bitmap_slice_committed(ShenandoahHeapRegion* r, bool skip_self) { 2254 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2255 2256 size_t regions_from = _bitmap_regions_per_slice * slice; 2257 size_t regions_to = MIN2(num_regions(), _bitmap_regions_per_slice * (slice + 1)); 2258 for (size_t g = regions_from; g < regions_to; g++) { 2259 assert (g / _bitmap_regions_per_slice == slice, "same slice"); 2260 if (skip_self && g == r->region_number()) continue; 2261 if (get_region(g)->is_committed()) { 2262 return true; 2263 } 2264 } 2265 return false; 2266 } 2267 2268 bool ShenandoahHeap::commit_bitmap_slice(ShenandoahHeapRegion* r) { 2269 assert_heaplock_owned_by_current_thread(); 2270 2271 // Bitmaps in special regions do not need commits 2272 if (_bitmap_region_special) { 2273 return true; 2274 } 2275 2276 if (is_bitmap_slice_committed(r, true)) { 2277 // Some other region from the group is already committed, meaning the bitmap 2278 // slice is already committed, we exit right away. 2279 return true; 2280 } 2281 2282 // Commit the bitmap slice: 2283 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2284 size_t off = _bitmap_bytes_per_slice * slice; 2285 size_t len = _bitmap_bytes_per_slice; 2286 if (!os::commit_memory((char*)_bitmap_region.start() + off, len, false)) { 2287 return false; 2288 } 2289 return true; 2290 } 2291 2292 bool ShenandoahHeap::uncommit_bitmap_slice(ShenandoahHeapRegion *r) { 2293 assert_heaplock_owned_by_current_thread(); 2294 2295 // Bitmaps in special regions do not need uncommits 2296 if (_bitmap_region_special) { 2297 return true; 2298 } 2299 2300 if (is_bitmap_slice_committed(r, true)) { 2301 // Some other region from the group is still committed, meaning the bitmap 2302 // slice is should stay committed, exit right away. 2303 return true; 2304 } 2305 2306 // Uncommit the bitmap slice: 2307 size_t slice = r->region_number() / _bitmap_regions_per_slice; 2308 size_t off = _bitmap_bytes_per_slice * slice; 2309 size_t len = _bitmap_bytes_per_slice; 2310 if (!os::uncommit_memory((char*)_bitmap_region.start() + off, len)) { 2311 return false; 2312 } 2313 return true; 2314 } 2315 2316 void ShenandoahHeap::vmop_entry_init_mark() { 2317 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2318 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2319 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark_gross); 2320 2321 try_inject_alloc_failure(); 2322 VM_ShenandoahInitMark op; 2323 VMThread::execute(&op); // jump to entry_init_mark() under safepoint 2324 } 2325 2326 void ShenandoahHeap::vmop_entry_final_mark() { 2327 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2328 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2329 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark_gross); 2330 2331 try_inject_alloc_failure(); 2332 VM_ShenandoahFinalMarkStartEvac op; 2333 VMThread::execute(&op); // jump to entry_final_mark under safepoint 2334 } 2335 2336 void ShenandoahHeap::vmop_entry_final_evac() { 2337 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2338 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2339 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac_gross); 2340 2341 VM_ShenandoahFinalEvac op; 2342 VMThread::execute(&op); // jump to entry_final_evac under safepoint 2343 } 2344 2345 void ShenandoahHeap::vmop_entry_init_updaterefs() { 2346 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2347 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2348 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs_gross); 2349 2350 try_inject_alloc_failure(); 2351 VM_ShenandoahInitUpdateRefs op; 2352 VMThread::execute(&op); 2353 } 2354 2355 void ShenandoahHeap::vmop_entry_final_updaterefs() { 2356 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2357 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2358 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs_gross); 2359 2360 try_inject_alloc_failure(); 2361 VM_ShenandoahFinalUpdateRefs op; 2362 VMThread::execute(&op); 2363 } 2364 2365 void ShenandoahHeap::vmop_entry_init_traversal() { 2366 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2367 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2368 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc_gross); 2369 2370 try_inject_alloc_failure(); 2371 VM_ShenandoahInitTraversalGC op; 2372 VMThread::execute(&op); 2373 } 2374 2375 void ShenandoahHeap::vmop_entry_final_traversal() { 2376 TraceCollectorStats tcs(monitoring_support()->stw_collection_counters()); 2377 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2378 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc_gross); 2379 2380 try_inject_alloc_failure(); 2381 VM_ShenandoahFinalTraversalGC op; 2382 VMThread::execute(&op); 2383 } 2384 2385 void ShenandoahHeap::vmop_entry_full(GCCause::Cause cause) { 2386 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2387 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2388 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc_gross); 2389 2390 try_inject_alloc_failure(); 2391 VM_ShenandoahFullGC op(cause); 2392 VMThread::execute(&op); 2393 } 2394 2395 void ShenandoahHeap::vmop_degenerated(ShenandoahDegenPoint point) { 2396 TraceCollectorStats tcs(monitoring_support()->full_stw_collection_counters()); 2397 ShenandoahGCPhase total(ShenandoahPhaseTimings::total_pause_gross); 2398 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc_gross); 2399 2400 VM_ShenandoahDegeneratedGC degenerated_gc((int)point); 2401 VMThread::execute(°enerated_gc); 2402 } 2403 2404 void ShenandoahHeap::entry_init_mark() { 2405 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2406 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_mark); 2407 2408 const char* msg = init_mark_event_message(); 2409 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2410 EventMark em("%s", msg); 2411 2412 ShenandoahWorkerScope scope(workers(), 2413 ShenandoahWorkerPolicy::calc_workers_for_init_marking(), 2414 "init marking"); 2415 2416 op_init_mark(); 2417 } 2418 2419 void ShenandoahHeap::entry_final_mark() { 2420 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2421 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_mark); 2422 2423 const char* msg = final_mark_event_message(); 2424 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2425 EventMark em("%s", msg); 2426 2427 ShenandoahWorkerScope scope(workers(), 2428 ShenandoahWorkerPolicy::calc_workers_for_final_marking(), 2429 "final marking"); 2430 2431 op_final_mark(); 2432 } 2433 2434 void ShenandoahHeap::entry_final_evac() { 2435 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2436 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_evac); 2437 2438 const char* msg = "Pause Final Evac"; 2439 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2440 EventMark em("%s", msg); 2441 2442 op_final_evac(); 2443 } 2444 2445 void ShenandoahHeap::entry_init_updaterefs() { 2446 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2447 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_update_refs); 2448 2449 static const char* msg = "Pause Init Update Refs"; 2450 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2451 EventMark em("%s", msg); 2452 2453 // No workers used in this phase, no setup required 2454 2455 op_init_updaterefs(); 2456 } 2457 2458 void ShenandoahHeap::entry_final_updaterefs() { 2459 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2460 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_update_refs); 2461 2462 static const char* msg = "Pause Final Update Refs"; 2463 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2464 EventMark em("%s", msg); 2465 2466 ShenandoahWorkerScope scope(workers(), 2467 ShenandoahWorkerPolicy::calc_workers_for_final_update_ref(), 2468 "final reference update"); 2469 2470 op_final_updaterefs(); 2471 } 2472 2473 void ShenandoahHeap::entry_init_traversal() { 2474 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2475 ShenandoahGCPhase phase(ShenandoahPhaseTimings::init_traversal_gc); 2476 2477 static const char* msg = "Pause Init Traversal"; 2478 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2479 EventMark em("%s", msg); 2480 2481 ShenandoahWorkerScope scope(workers(), 2482 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2483 "init traversal"); 2484 2485 op_init_traversal(); 2486 } 2487 2488 void ShenandoahHeap::entry_final_traversal() { 2489 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2490 ShenandoahGCPhase phase(ShenandoahPhaseTimings::final_traversal_gc); 2491 2492 static const char* msg = "Pause Final Traversal"; 2493 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id()); 2494 EventMark em("%s", msg); 2495 2496 ShenandoahWorkerScope scope(workers(), 2497 ShenandoahWorkerPolicy::calc_workers_for_stw_traversal(), 2498 "final traversal"); 2499 2500 op_final_traversal(); 2501 } 2502 2503 void ShenandoahHeap::entry_full(GCCause::Cause cause) { 2504 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2505 ShenandoahGCPhase phase(ShenandoahPhaseTimings::full_gc); 2506 2507 static const char* msg = "Pause Full"; 2508 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true); 2509 EventMark em("%s", msg); 2510 2511 ShenandoahWorkerScope scope(workers(), 2512 ShenandoahWorkerPolicy::calc_workers_for_fullgc(), 2513 "full gc"); 2514 2515 op_full(cause); 2516 } 2517 2518 void ShenandoahHeap::entry_degenerated(int point) { 2519 ShenandoahGCPhase total_phase(ShenandoahPhaseTimings::total_pause); 2520 ShenandoahGCPhase phase(ShenandoahPhaseTimings::degen_gc); 2521 2522 ShenandoahDegenPoint dpoint = (ShenandoahDegenPoint)point; 2523 const char* msg = degen_event_message(dpoint); 2524 GCTraceTime time(msg, PrintGC, _gc_timer, tracer()->gc_id(), true); 2525 EventMark em("%s", msg); 2526 2527 ShenandoahWorkerScope scope(workers(), 2528 ShenandoahWorkerPolicy::calc_workers_for_stw_degenerated(), 2529 "stw degenerated gc"); 2530 2531 set_degenerated_gc_in_progress(true); 2532 op_degenerated(dpoint); 2533 set_degenerated_gc_in_progress(false); 2534 } 2535 2536 void ShenandoahHeap::entry_mark() { 2537 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2538 2539 const char* msg = conc_mark_event_message(); 2540 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2541 EventMark em("%s", msg); 2542 2543 ShenandoahWorkerScope scope(workers(), 2544 ShenandoahWorkerPolicy::calc_workers_for_conc_marking(), 2545 "concurrent marking"); 2546 2547 try_inject_alloc_failure(); 2548 op_mark(); 2549 } 2550 2551 void ShenandoahHeap::entry_evac() { 2552 ShenandoahGCPhase conc_evac_phase(ShenandoahPhaseTimings::conc_evac); 2553 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2554 2555 static const char *msg = "Concurrent evacuation"; 2556 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2557 EventMark em("%s", msg); 2558 2559 ShenandoahWorkerScope scope(workers(), 2560 ShenandoahWorkerPolicy::calc_workers_for_conc_evac(), 2561 "concurrent evacuation"); 2562 2563 try_inject_alloc_failure(); 2564 op_conc_evac(); 2565 } 2566 2567 void ShenandoahHeap::entry_updaterefs() { 2568 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_update_refs); 2569 2570 static const char* msg = "Concurrent update references"; 2571 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2572 EventMark em("%s", msg); 2573 2574 ShenandoahWorkerScope scope(workers(), 2575 ShenandoahWorkerPolicy::calc_workers_for_conc_update_ref(), 2576 "concurrent reference update"); 2577 2578 try_inject_alloc_failure(); 2579 op_updaterefs(); 2580 } 2581 2582 void ShenandoahHeap::entry_cleanup() { 2583 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_cleanup); 2584 2585 static const char* msg = "Concurrent cleanup"; 2586 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2587 EventMark em("%s", msg); 2588 2589 // This phase does not use workers, no need for setup 2590 2591 try_inject_alloc_failure(); 2592 op_cleanup(); 2593 } 2594 2595 void ShenandoahHeap::entry_reset() { 2596 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_reset); 2597 2598 static const char* msg = "Concurrent reset"; 2599 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2600 EventMark em("%s", msg); 2601 2602 ShenandoahWorkerScope scope(workers(), 2603 ShenandoahWorkerPolicy::calc_workers_for_conc_reset(), 2604 "concurrent reset"); 2605 2606 try_inject_alloc_failure(); 2607 op_reset(); 2608 } 2609 2610 void ShenandoahHeap::entry_preclean() { 2611 if (ShenandoahPreclean && process_references()) { 2612 ShenandoahGCPhase conc_preclean(ShenandoahPhaseTimings::conc_preclean); 2613 2614 static const char* msg = "Concurrent precleaning"; 2615 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2616 EventMark em("%s", msg); 2617 2618 ShenandoahWorkerScope scope(workers(), 2619 ShenandoahWorkerPolicy::calc_workers_for_conc_preclean(), 2620 "concurrent preclean", 2621 /* check_workers = */ false); 2622 2623 try_inject_alloc_failure(); 2624 op_preclean(); 2625 } 2626 } 2627 2628 void ShenandoahHeap::entry_traversal() { 2629 static const char* msg = "Concurrent traversal"; 2630 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2631 EventMark em("%s", msg); 2632 2633 TraceCollectorStats tcs(monitoring_support()->concurrent_collection_counters()); 2634 2635 ShenandoahWorkerScope scope(workers(), 2636 ShenandoahWorkerPolicy::calc_workers_for_conc_traversal(), 2637 "concurrent traversal"); 2638 2639 try_inject_alloc_failure(); 2640 op_traversal(); 2641 } 2642 2643 void ShenandoahHeap::entry_uncommit(double shrink_before) { 2644 static const char *msg = "Concurrent uncommit"; 2645 GCTraceTime time(msg, PrintGC, NULL, tracer()->gc_id(), true); 2646 EventMark em("%s", msg); 2647 2648 ShenandoahGCPhase phase(ShenandoahPhaseTimings::conc_uncommit); 2649 2650 op_uncommit(shrink_before); 2651 } 2652 2653 void ShenandoahHeap::try_inject_alloc_failure() { 2654 if (ShenandoahAllocFailureALot && !cancelled_gc() && ((os::random() % 1000) > 950)) { 2655 _inject_alloc_failure.set(); 2656 os::naked_short_sleep(1); 2657 if (cancelled_gc()) { 2658 log_info(gc)("Allocation failure was successfully injected"); 2659 } 2660 } 2661 } 2662 2663 bool ShenandoahHeap::should_inject_alloc_failure() { 2664 return _inject_alloc_failure.is_set() && _inject_alloc_failure.try_unset(); 2665 } 2666 2667 void ShenandoahHeap::enter_evacuation() { 2668 _oom_evac_handler.enter_evacuation(); 2669 } 2670 2671 void ShenandoahHeap::leave_evacuation() { 2672 _oom_evac_handler.leave_evacuation(); 2673 } 2674 2675 ShenandoahRegionIterator::ShenandoahRegionIterator() : 2676 _heap(ShenandoahHeap::heap()), 2677 _index(0) {} 2678 2679 ShenandoahRegionIterator::ShenandoahRegionIterator(ShenandoahHeap* heap) : 2680 _heap(heap), 2681 _index(0) {} 2682 2683 void ShenandoahRegionIterator::reset() { 2684 _index = 0; 2685 } 2686 2687 bool ShenandoahRegionIterator::has_next() const { 2688 return _index < (jint)_heap->num_regions(); 2689 } 2690 2691 char ShenandoahHeap::gc_state() { 2692 return _gc_state.raw_value(); 2693 } 2694 2695 const char* ShenandoahHeap::init_mark_event_message() const { 2696 bool update_refs = has_forwarded_objects(); 2697 bool proc_refs = process_references(); 2698 bool unload_cls = unload_classes(); 2699 2700 if (update_refs && proc_refs && unload_cls) { 2701 return "Pause Init Mark (update refs) (process weakrefs) (unload classes)"; 2702 } else if (update_refs && proc_refs) { 2703 return "Pause Init Mark (update refs) (process weakrefs)"; 2704 } else if (update_refs && unload_cls) { 2705 return "Pause Init Mark (update refs) (unload classes)"; 2706 } else if (proc_refs && unload_cls) { 2707 return "Pause Init Mark (process weakrefs) (unload classes)"; 2708 } else if (update_refs) { 2709 return "Pause Init Mark (update refs)"; 2710 } else if (proc_refs) { 2711 return "Pause Init Mark (process weakrefs)"; 2712 } else if (unload_cls) { 2713 return "Pause Init Mark (unload classes)"; 2714 } else { 2715 return "Pause Init Mark"; 2716 } 2717 } 2718 2719 const char* ShenandoahHeap::final_mark_event_message() const { 2720 bool update_refs = has_forwarded_objects(); 2721 bool proc_refs = process_references(); 2722 bool unload_cls = unload_classes(); 2723 2724 if (update_refs && proc_refs && unload_cls) { 2725 return "Pause Final Mark (update refs) (process weakrefs) (unload classes)"; 2726 } else if (update_refs && proc_refs) { 2727 return "Pause Final Mark (update refs) (process weakrefs)"; 2728 } else if (update_refs && unload_cls) { 2729 return "Pause Final Mark (update refs) (unload classes)"; 2730 } else if (proc_refs && unload_cls) { 2731 return "Pause Final Mark (process weakrefs) (unload classes)"; 2732 } else if (update_refs) { 2733 return "Pause Final Mark (update refs)"; 2734 } else if (proc_refs) { 2735 return "Pause Final Mark (process weakrefs)"; 2736 } else if (unload_cls) { 2737 return "Pause Final Mark (unload classes)"; 2738 } else { 2739 return "Pause Final Mark"; 2740 } 2741 } 2742 2743 const char* ShenandoahHeap::conc_mark_event_message() const { 2744 bool update_refs = has_forwarded_objects(); 2745 bool proc_refs = process_references(); 2746 bool unload_cls = unload_classes(); 2747 2748 if (update_refs && proc_refs && unload_cls) { 2749 return "Concurrent marking (update refs) (process weakrefs) (unload classes)"; 2750 } else if (update_refs && proc_refs) { 2751 return "Concurrent marking (update refs) (process weakrefs)"; 2752 } else if (update_refs && unload_cls) { 2753 return "Concurrent marking (update refs) (unload classes)"; 2754 } else if (proc_refs && unload_cls) { 2755 return "Concurrent marking (process weakrefs) (unload classes)"; 2756 } else if (update_refs) { 2757 return "Concurrent marking (update refs)"; 2758 } else if (proc_refs) { 2759 return "Concurrent marking (process weakrefs)"; 2760 } else if (unload_cls) { 2761 return "Concurrent marking (unload classes)"; 2762 } else { 2763 return "Concurrent marking"; 2764 } 2765 } 2766 2767 const char* ShenandoahHeap::degen_event_message(ShenandoahDegenPoint point) const { 2768 switch (point) { 2769 case _degenerated_unset: 2770 return "Pause Degenerated GC (<UNSET>)"; 2771 case _degenerated_traversal: 2772 return "Pause Degenerated GC (Traversal)"; 2773 case _degenerated_outside_cycle: 2774 return "Pause Degenerated GC (Outside of Cycle)"; 2775 case _degenerated_mark: 2776 return "Pause Degenerated GC (Mark)"; 2777 case _degenerated_evac: 2778 return "Pause Degenerated GC (Evacuation)"; 2779 case _degenerated_updaterefs: 2780 return "Pause Degenerated GC (Update Refs)"; 2781 default: 2782 ShouldNotReachHere(); 2783 return "ERROR"; 2784 } 2785 } 2786 2787 jushort* ShenandoahHeap::get_liveness_cache(uint worker_id) { 2788 #ifdef ASSERT 2789 assert(_liveness_cache != NULL, "sanity"); 2790 assert(worker_id < _max_workers, "sanity"); 2791 for (uint i = 0; i < num_regions(); i++) { 2792 assert(_liveness_cache[worker_id][i] == 0, "liveness cache should be empty"); 2793 } 2794 #endif 2795 return _liveness_cache[worker_id]; 2796 } 2797 2798 void ShenandoahHeap::flush_liveness_cache(uint worker_id) { 2799 assert(worker_id < _max_workers, "sanity"); 2800 assert(_liveness_cache != NULL, "sanity"); 2801 jushort* ld = _liveness_cache[worker_id]; 2802 for (uint i = 0; i < num_regions(); i++) { 2803 ShenandoahHeapRegion* r = get_region(i); 2804 jushort live = ld[i]; 2805 if (live > 0) { 2806 r->increase_live_data_gc_words(live); 2807 ld[i] = 0; 2808 } 2809 } 2810 }