1 /* 2 * Copyright (c) 2015, 2020, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24 #include "precompiled.hpp" 25 #include "gc/shared/locationPrinter.hpp" 26 #include "gc/z/zAddress.inline.hpp" 27 #include "gc/z/zGlobals.hpp" 28 #include "gc/z/zHeap.inline.hpp" 29 #include "gc/z/zHeapIterator.hpp" 30 #include "gc/z/zHeuristics.hpp" 31 #include "gc/z/zMark.inline.hpp" 32 #include "gc/z/zPage.inline.hpp" 33 #include "gc/z/zPageTable.inline.hpp" 34 #include "gc/z/zRelocationSet.inline.hpp" 35 #include "gc/z/zRelocationSetSelector.inline.hpp" 36 #include "gc/z/zResurrection.hpp" 37 #include "gc/z/zStat.hpp" 38 #include "gc/z/zThread.inline.hpp" 39 #include "gc/z/zVerify.hpp" 40 #include "gc/z/zWorkers.inline.hpp" 41 #include "logging/log.hpp" 42 #include "memory/iterator.hpp" 43 #include "memory/resourceArea.hpp" 44 #include "runtime/handshake.hpp" 45 #include "runtime/safepoint.hpp" 46 #include "runtime/thread.hpp" 47 #include "utilities/debug.hpp" 48 49 static const ZStatSampler ZSamplerHeapUsedBeforeMark("Memory", "Heap Used Before Mark", ZStatUnitBytes); 50 static const ZStatSampler ZSamplerHeapUsedAfterMark("Memory", "Heap Used After Mark", ZStatUnitBytes); 51 static const ZStatSampler ZSamplerHeapUsedBeforeRelocation("Memory", "Heap Used Before Relocation", ZStatUnitBytes); 52 static const ZStatSampler ZSamplerHeapUsedAfterRelocation("Memory", "Heap Used After Relocation", ZStatUnitBytes); 53 static const ZStatCounter ZCounterUndoPageAllocation("Memory", "Undo Page Allocation", ZStatUnitOpsPerSecond); 54 static const ZStatCounter ZCounterOutOfMemory("Memory", "Out Of Memory", ZStatUnitOpsPerSecond); 55 56 ZHeap* ZHeap::_heap = NULL; 57 58 ZHeap::ZHeap() : 59 _workers(), 60 _object_allocator(), 61 _page_allocator(&_workers, MinHeapSize, InitialHeapSize, MaxHeapSize, ZHeuristics::max_reserve()), 62 _page_table(), 63 _forwarding_table(), 64 _mark(&_workers, &_page_table), 65 _reference_processor(&_workers), 66 _weak_roots_processor(&_workers), 67 _relocate(&_workers), 68 _relocation_set(), 69 _unload(&_workers), 70 _serviceability(min_capacity(), max_capacity()) { 71 // Install global heap instance 72 assert(_heap == NULL, "Already initialized"); 73 _heap = this; 74 75 // Update statistics 76 ZStatHeap::set_at_initialize(min_capacity(), max_capacity(), max_reserve()); 77 } 78 79 bool ZHeap::is_initialized() const { 80 return _page_allocator.is_initialized() && _mark.is_initialized(); 81 } 82 83 size_t ZHeap::min_capacity() const { 84 return _page_allocator.min_capacity(); 85 } 86 87 size_t ZHeap::max_capacity() const { 88 return _page_allocator.max_capacity(); 89 } 90 91 size_t ZHeap::soft_max_capacity() const { 92 return _page_allocator.soft_max_capacity(); 93 } 94 95 size_t ZHeap::capacity() const { 96 return _page_allocator.capacity(); 97 } 98 99 size_t ZHeap::max_reserve() const { 100 return _page_allocator.max_reserve(); 101 } 102 103 size_t ZHeap::used_high() const { 104 return _page_allocator.used_high(); 105 } 106 107 size_t ZHeap::used_low() const { 108 return _page_allocator.used_low(); 109 } 110 111 size_t ZHeap::used() const { 112 return _page_allocator.used(); 113 } 114 115 size_t ZHeap::unused() const { 116 return _page_allocator.unused(); 117 } 118 119 size_t ZHeap::allocated() const { 120 return _page_allocator.allocated(); 121 } 122 123 size_t ZHeap::reclaimed() const { 124 return _page_allocator.reclaimed(); 125 } 126 127 size_t ZHeap::tlab_capacity() const { 128 return capacity(); 129 } 130 131 size_t ZHeap::tlab_used() const { 132 return _object_allocator.used(); 133 } 134 135 size_t ZHeap::max_tlab_size() const { 136 return ZObjectSizeLimitSmall; 137 } 138 139 size_t ZHeap::unsafe_max_tlab_alloc() const { 140 size_t size = _object_allocator.remaining(); 141 142 if (size < MinTLABSize) { 143 // The remaining space in the allocator is not enough to 144 // fit the smallest possible TLAB. This means that the next 145 // TLAB allocation will force the allocator to get a new 146 // backing page anyway, which in turn means that we can then 147 // fit the largest possible TLAB. 148 size = max_tlab_size(); 149 } 150 151 return MIN2(size, max_tlab_size()); 152 } 153 154 bool ZHeap::is_in(uintptr_t addr) const { 155 // An address is considered to be "in the heap" if it points into 156 // the allocated part of a page, regardless of which heap view is 157 // used. Note that an address with the finalizable metadata bit set 158 // is not pointing into a heap view, and therefore not considered 159 // to be "in the heap". 160 161 if (ZAddress::is_in(addr)) { 162 const ZPage* const page = _page_table.get(addr); 163 if (page != NULL) { 164 return page->is_in(addr); 165 } 166 } 167 168 return false; 169 } 170 171 uint ZHeap::nconcurrent_worker_threads() const { 172 return _workers.nconcurrent(); 173 } 174 175 uint ZHeap::nconcurrent_no_boost_worker_threads() const { 176 return _workers.nconcurrent_no_boost(); 177 } 178 179 void ZHeap::set_boost_worker_threads(bool boost) { 180 _workers.set_boost(boost); 181 } 182 183 void ZHeap::threads_do(ThreadClosure* tc) const { 184 _page_allocator.threads_do(tc); 185 _workers.threads_do(tc); 186 } 187 188 void ZHeap::out_of_memory() { 189 ResourceMark rm; 190 191 ZStatInc(ZCounterOutOfMemory); 192 log_info(gc)("Out Of Memory (%s)", Thread::current()->name()); 193 } 194 195 ZPage* ZHeap::alloc_page(uint8_t type, size_t size, ZAllocationFlags flags) { 196 ZPage* const page = _page_allocator.alloc_page(type, size, flags); 197 if (page != NULL) { 198 // Insert page table entry 199 _page_table.insert(page); 200 } 201 202 return page; 203 } 204 205 void ZHeap::undo_alloc_page(ZPage* page) { 206 assert(page->is_allocating(), "Invalid page state"); 207 208 ZStatInc(ZCounterUndoPageAllocation); 209 log_trace(gc)("Undo page allocation, thread: " PTR_FORMAT " (%s), page: " PTR_FORMAT ", size: " SIZE_FORMAT, 210 ZThread::id(), ZThread::name(), p2i(page), page->size()); 211 212 free_page(page, false /* reclaimed */); 213 } 214 215 void ZHeap::free_page(ZPage* page, bool reclaimed) { 216 // Remove page table entry 217 _page_table.remove(page); 218 219 // Free page 220 _page_allocator.free_page(page, reclaimed); 221 } 222 223 void ZHeap::flip_to_marked() { 224 ZVerifyViewsFlip flip(&_page_allocator); 225 ZAddress::flip_to_marked(); 226 } 227 228 void ZHeap::flip_to_remapped() { 229 ZVerifyViewsFlip flip(&_page_allocator); 230 ZAddress::flip_to_remapped(); 231 } 232 233 void ZHeap::mark_start() { 234 assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint"); 235 236 // Update statistics 237 ZStatSample(ZSamplerHeapUsedBeforeMark, used()); 238 239 // Flip address view 240 flip_to_marked(); 241 242 // Retire allocating pages 243 _object_allocator.retire_pages(); 244 245 // Reset allocated/reclaimed/used statistics 246 _page_allocator.reset_statistics(); 247 248 // Reset encountered/dropped/enqueued statistics 249 _reference_processor.reset_statistics(); 250 251 // Enter mark phase 252 ZGlobalPhase = ZPhaseMark; 253 254 // Reset marking information and mark roots 255 _mark.start(); 256 257 // Update statistics 258 ZStatHeap::set_at_mark_start(soft_max_capacity(), capacity(), used()); 259 } 260 261 void ZHeap::mark(bool initial) { 262 _mark.mark(initial); 263 } 264 265 void ZHeap::mark_flush_and_free(Thread* thread) { 266 _mark.flush_and_free(thread); 267 } 268 269 bool ZHeap::mark_end() { 270 assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint"); 271 272 // Try end marking 273 if (!_mark.end()) { 274 // Marking not completed, continue concurrent mark 275 return false; 276 } 277 278 // Enter mark completed phase 279 ZGlobalPhase = ZPhaseMarkCompleted; 280 281 // Verify after mark 282 ZVerify::after_mark(); 283 284 // Update statistics 285 ZStatSample(ZSamplerHeapUsedAfterMark, used()); 286 ZStatHeap::set_at_mark_end(capacity(), allocated(), used()); 287 288 // Block resurrection of weak/phantom references 289 ZResurrection::block(); 290 291 // Process weak roots 292 _weak_roots_processor.process_weak_roots(); 293 294 // Prepare to unload stale metadata and nmethods 295 _unload.prepare(); 296 297 return true; 298 } 299 300 void ZHeap::keep_alive(oop obj) { 301 ZBarrier::keep_alive_barrier_on_oop(obj); 302 } 303 304 void ZHeap::set_soft_reference_policy(bool clear) { 305 _reference_processor.set_soft_reference_policy(clear); 306 } 307 308 class ZRendezvousClosure : public HandshakeClosure { 309 public: 310 ZRendezvousClosure() : 311 HandshakeClosure("ZRendezvous") {} 312 313 void do_thread(Thread* thread) {} 314 }; 315 316 void ZHeap::process_non_strong_references() { 317 // Process Soft/Weak/Final/PhantomReferences 318 _reference_processor.process_references(); 319 320 // Process concurrent weak roots 321 _weak_roots_processor.process_concurrent_weak_roots(); 322 323 // Unlink stale metadata and nmethods 324 _unload.unlink(); 325 326 // Perform a handshake. This is needed 1) to make sure that stale 327 // metadata and nmethods are no longer observable. And 2), to 328 // prevent the race where a mutator first loads an oop, which is 329 // logically null but not yet cleared. Then this oop gets cleared 330 // by the reference processor and resurrection is unblocked. At 331 // this point the mutator could see the unblocked state and pass 332 // this invalid oop through the normal barrier path, which would 333 // incorrectly try to mark the oop. 334 ZRendezvousClosure cl; 335 Handshake::execute(&cl); 336 337 // Unblock resurrection of weak/phantom references 338 ZResurrection::unblock(); 339 340 // Purge stale metadata and nmethods that were unlinked 341 _unload.purge(); 342 343 // Enqueue Soft/Weak/Final/PhantomReferences. Note that this 344 // must be done after unblocking resurrection. Otherwise the 345 // Finalizer thread could call Reference.get() on the Finalizers 346 // that were just enqueued, which would incorrectly return null 347 // during the resurrection block window, since such referents 348 // are only Finalizable marked. 349 _reference_processor.enqueue_references(); 350 } 351 352 void ZHeap::select_relocation_set() { 353 // Do not allow pages to be deleted 354 _page_allocator.enable_deferred_delete(); 355 356 // Register relocatable pages with selector 357 ZRelocationSetSelector selector; 358 ZPageTableIterator pt_iter(&_page_table); 359 for (ZPage* page; pt_iter.next(&page);) { 360 if (!page->is_relocatable()) { 361 // Not relocatable, don't register 362 continue; 363 } 364 365 if (page->is_marked()) { 366 // Register live page 367 selector.register_live_page(page); 368 } else { 369 // Register garbage page 370 selector.register_garbage_page(page); 371 372 // Reclaim page immediately 373 free_page(page, true /* reclaimed */); 374 } 375 } 376 377 // Allow pages to be deleted 378 _page_allocator.disable_deferred_delete(); 379 380 // Select pages to relocate 381 selector.select(&_relocation_set); 382 383 // Setup forwarding table 384 ZRelocationSetIterator rs_iter(&_relocation_set); 385 for (ZForwarding* forwarding; rs_iter.next(&forwarding);) { 386 _forwarding_table.insert(forwarding); 387 } 388 389 // Update statistics 390 ZStatRelocation::set_at_select_relocation_set(selector.stats()); 391 ZStatHeap::set_at_select_relocation_set(selector.stats(), reclaimed()); 392 } 393 394 void ZHeap::reset_relocation_set() { 395 // Reset forwarding table 396 ZRelocationSetIterator iter(&_relocation_set); 397 for (ZForwarding* forwarding; iter.next(&forwarding);) { 398 _forwarding_table.remove(forwarding); 399 } 400 401 // Reset relocation set 402 _relocation_set.reset(); 403 } 404 405 void ZHeap::relocate_start() { 406 assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint"); 407 408 // Finish unloading stale metadata and nmethods 409 _unload.finish(); 410 411 // Flip address view 412 flip_to_remapped(); 413 414 // Enter relocate phase 415 ZGlobalPhase = ZPhaseRelocate; 416 417 // Update statistics 418 ZStatSample(ZSamplerHeapUsedBeforeRelocation, used()); 419 ZStatHeap::set_at_relocate_start(capacity(), allocated(), used()); 420 421 // Remap/Relocate roots 422 _relocate.start(); 423 } 424 425 void ZHeap::relocate() { 426 // Relocate relocation set 427 const bool success = _relocate.relocate(&_relocation_set); 428 429 // Update statistics 430 ZStatSample(ZSamplerHeapUsedAfterRelocation, used()); 431 ZStatRelocation::set_at_relocate_end(success); 432 ZStatHeap::set_at_relocate_end(capacity(), allocated(), reclaimed(), 433 used(), used_high(), used_low()); 434 } 435 436 void ZHeap::object_iterate(ObjectClosure* cl, bool visit_weaks) { 437 assert(SafepointSynchronize::is_at_safepoint(), "Should be at safepoint"); 438 439 ZHeapIterator iter; 440 iter.objects_do(cl, visit_weaks); 441 } 442 443 void ZHeap::pages_do(ZPageClosure* cl) { 444 ZPageTableIterator iter(&_page_table); 445 for (ZPage* page; iter.next(&page);) { 446 cl->do_page(page); 447 } 448 _page_allocator.pages_do(cl); 449 } 450 451 void ZHeap::serviceability_initialize() { 452 _serviceability.initialize(); 453 } 454 455 GCMemoryManager* ZHeap::serviceability_memory_manager() { 456 return _serviceability.memory_manager(); 457 } 458 459 MemoryPool* ZHeap::serviceability_memory_pool() { 460 return _serviceability.memory_pool(); 461 } 462 463 ZServiceabilityCounters* ZHeap::serviceability_counters() { 464 return _serviceability.counters(); 465 } 466 467 void ZHeap::print_on(outputStream* st) const { 468 st->print_cr(" ZHeap used " SIZE_FORMAT "M, capacity " SIZE_FORMAT "M, max capacity " SIZE_FORMAT "M", 469 used() / M, 470 capacity() / M, 471 max_capacity() / M); 472 MetaspaceUtils::print_on(st); 473 } 474 475 void ZHeap::print_extended_on(outputStream* st) const { 476 print_on(st); 477 st->cr(); 478 479 // Do not allow pages to be deleted 480 _page_allocator.enable_deferred_delete(); 481 482 // Print all pages 483 st->print_cr("ZGC Page Table:"); 484 ZPageTableIterator iter(&_page_table); 485 for (ZPage* page; iter.next(&page);) { 486 page->print_on(st); 487 } 488 489 // Allow pages to be deleted 490 _page_allocator.enable_deferred_delete(); 491 } 492 493 bool ZHeap::print_location(outputStream* st, uintptr_t addr) const { 494 if (LocationPrinter::is_valid_obj((void*)addr)) { 495 st->print(PTR_FORMAT " is a %s oop: ", addr, ZAddress::is_good(addr) ? "good" : "bad"); 496 ZOop::from_address(addr)->print_on(st); 497 return true; 498 } 499 500 return false; 501 } 502 503 void ZHeap::verify() { 504 // Heap verification can only be done between mark end and 505 // relocate start. This is the only window where all oop are 506 // good and the whole heap is in a consistent state. 507 guarantee(ZGlobalPhase == ZPhaseMarkCompleted, "Invalid phase"); 508 509 ZVerify::after_weak_processing(); 510 }