1 /* 2 * Copyright (c) 2017, 2018, 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 "code/relocInfo.hpp" 26 #include "code/nmethod.hpp" 27 #include "code/icBuffer.hpp" 28 #include "gc/shared/barrierSet.hpp" 29 #include "gc/shared/barrierSetNMethod.hpp" 30 #include "gc/z/zArray.inline.hpp" 31 #include "gc/z/zGlobals.hpp" 32 #include "gc/z/zHash.inline.hpp" 33 #include "gc/z/zLock.inline.hpp" 34 #include "gc/z/zNMethodTable.hpp" 35 #include "gc/z/zOopClosures.inline.hpp" 36 #include "gc/z/zTask.hpp" 37 #include "gc/z/zWorkers.hpp" 38 #include "logging/log.hpp" 39 #include "memory/allocation.inline.hpp" 40 #include "memory/resourceArea.hpp" 41 #include "runtime/atomic.hpp" 42 #include "runtime/orderAccess.hpp" 43 #include "runtime/os.hpp" 44 #include "utilities/debug.hpp" 45 46 class ZNMethodDataImmediateOops { 47 private: 48 const size_t _nimmediate_oops; 49 50 static size_t header_size(); 51 52 ZNMethodDataImmediateOops(const GrowableArray<oop*>& immediate_oops); 53 54 public: 55 static ZNMethodDataImmediateOops* create(const GrowableArray<oop*>& immediate_oops); 56 static void destroy(ZNMethodDataImmediateOops* data_immediate_oops); 57 58 size_t immediate_oops_count() const; 59 oop** immediate_oops_begin() const; 60 oop** immediate_oops_end() const; 61 }; 62 63 size_t ZNMethodDataImmediateOops::header_size() { 64 const size_t size = sizeof(ZNMethodDataImmediateOops); 65 assert(is_aligned(size, sizeof(oop*)), "Header misaligned"); 66 return size; 67 } 68 69 ZNMethodDataImmediateOops* ZNMethodDataImmediateOops::create(const GrowableArray<oop*>& immediate_oops) { 70 // Allocate memory for the ZNMethodDataImmediateOops object 71 // plus the immediate oop* array that follows right after. 72 const size_t size = ZNMethodDataImmediateOops::header_size() + (sizeof(oop*) * immediate_oops.length()); 73 void* const data_immediate_oops = NEW_C_HEAP_ARRAY(uint8_t, size, mtGC); 74 return ::new (data_immediate_oops) ZNMethodDataImmediateOops(immediate_oops); 75 } 76 77 void ZNMethodDataImmediateOops::destroy(ZNMethodDataImmediateOops* data_immediate_oops) { 78 ZNMethodTable::safe_delete(data_immediate_oops); 79 } 80 81 ZNMethodDataImmediateOops::ZNMethodDataImmediateOops(const GrowableArray<oop*>& immediate_oops) : 82 _nimmediate_oops(immediate_oops.length()) { 83 // Save all immediate oops 84 for (size_t i = 0; i < _nimmediate_oops; i++) { 85 immediate_oops_begin()[i] = immediate_oops.at(i); 86 } 87 } 88 89 size_t ZNMethodDataImmediateOops::immediate_oops_count() const { 90 return _nimmediate_oops; 91 } 92 93 oop** ZNMethodDataImmediateOops::immediate_oops_begin() const { 94 // The immediate oop* array starts immediately after this object 95 return (oop**)((uintptr_t)this + header_size()); 96 } 97 98 oop** ZNMethodDataImmediateOops::immediate_oops_end() const { 99 return immediate_oops_begin() + immediate_oops_count(); 100 } 101 102 class ZNMethodData { 103 private: 104 ZReentrantLock _lock; 105 ZNMethodDataImmediateOops* volatile _immediate_oops; 106 107 ZNMethodData(nmethod* nm); 108 109 public: 110 static ZNMethodData* create(nmethod* nm); 111 static void destroy(ZNMethodData* data); 112 113 ZReentrantLock* lock(); 114 115 ZNMethodDataImmediateOops* immediate_oops() const; 116 ZNMethodDataImmediateOops* swap_immediate_oops(const GrowableArray<oop*>& immediate_oops); 117 }; 118 119 ZNMethodData* ZNMethodData::create(nmethod* nm) { 120 void* const method = NEW_C_HEAP_ARRAY(uint8_t, sizeof(ZNMethodData), mtGC); 121 return ::new (method) ZNMethodData(nm); 122 } 123 124 void ZNMethodData::destroy(ZNMethodData* data) { 125 ZNMethodDataImmediateOops::destroy(data->immediate_oops()); 126 ZNMethodTable::safe_delete(data); 127 } 128 129 ZNMethodData::ZNMethodData(nmethod* nm) : 130 _lock(), 131 _immediate_oops(NULL) {} 132 133 ZReentrantLock* ZNMethodData::lock() { 134 return &_lock; 135 } 136 137 ZNMethodDataImmediateOops* ZNMethodData::immediate_oops() const { 138 return OrderAccess::load_acquire(&_immediate_oops); 139 } 140 141 ZNMethodDataImmediateOops* ZNMethodData::swap_immediate_oops(const GrowableArray<oop*>& immediate_oops) { 142 ZNMethodDataImmediateOops* const data_immediate_oops = 143 immediate_oops.is_empty() ? NULL : ZNMethodDataImmediateOops::create(immediate_oops); 144 return Atomic::xchg(data_immediate_oops, &_immediate_oops); 145 } 146 147 static ZNMethodData* gc_data(const nmethod* nm) { 148 return nm->gc_data<ZNMethodData>(); 149 } 150 151 static void set_gc_data(nmethod* nm, ZNMethodData* data) { 152 return nm->set_gc_data<ZNMethodData>(data); 153 } 154 155 ZNMethodTableEntry* ZNMethodTable::_table = NULL; 156 size_t ZNMethodTable::_size = 0; 157 ZLock ZNMethodTable::_iter_lock; 158 ZNMethodTableEntry* ZNMethodTable::_iter_table = NULL; 159 size_t ZNMethodTable::_iter_table_size = 0; 160 ZArray<void*> ZNMethodTable::_iter_deferred_deletes; 161 size_t ZNMethodTable::_nregistered = 0; 162 size_t ZNMethodTable::_nunregistered = 0; 163 volatile size_t ZNMethodTable::_claimed = 0; 164 165 void ZNMethodTable::safe_delete(void* data) { 166 if (data == NULL) { 167 return; 168 } 169 170 ZLocker<ZLock> locker(&_iter_lock); 171 if (_iter_table != NULL) { 172 // Iteration in progress, defer delete 173 _iter_deferred_deletes.add(data); 174 } else { 175 // Iteration not in progress, delete now 176 FREE_C_HEAP_ARRAY(uint8_t, data); 177 } 178 } 179 180 ZNMethodTableEntry ZNMethodTable::create_entry(nmethod* nm) { 181 GrowableArray<oop*> immediate_oops; 182 bool non_immediate_oops = false; 183 184 // Find all oops relocations 185 RelocIterator iter(nm); 186 while (iter.next()) { 187 if (iter.type() != relocInfo::oop_type) { 188 // Not an oop 189 continue; 190 } 191 192 oop_Relocation* r = iter.oop_reloc(); 193 194 if (!r->oop_is_immediate()) { 195 // Non-immediate oop found 196 non_immediate_oops = true; 197 continue; 198 } 199 200 if (r->oop_value() != NULL) { 201 // Non-NULL immediate oop found. NULL oops can safely be 202 // ignored since the method will be re-registered if they 203 // are later patched to be non-NULL. 204 immediate_oops.push(r->oop_addr()); 205 } 206 } 207 208 // Attach GC data to nmethod 209 ZNMethodData* data = gc_data(nm); 210 if (data == NULL) { 211 data = ZNMethodData::create(nm); 212 set_gc_data(nm, data); 213 } 214 215 // Attach immediate oops in GC data 216 ZNMethodDataImmediateOops* const old_data_immediate_oops = data->swap_immediate_oops(immediate_oops); 217 ZNMethodDataImmediateOops::destroy(old_data_immediate_oops); 218 219 // Create entry 220 return ZNMethodTableEntry(nm, non_immediate_oops, !immediate_oops.is_empty()); 221 } 222 223 ZReentrantLock* ZNMethodTable::lock_for_nmethod(nmethod* nm) { 224 ZNMethodData* const data = gc_data(nm); 225 if (data == NULL) { 226 return NULL; 227 } 228 return data->lock(); 229 } 230 231 size_t ZNMethodTable::first_index(const nmethod* nm, size_t size) { 232 assert(is_power_of_2(size), "Invalid size"); 233 const size_t mask = size - 1; 234 const size_t hash = ZHash::address_to_uint32((uintptr_t)nm); 235 return hash & mask; 236 } 237 238 size_t ZNMethodTable::next_index(size_t prev_index, size_t size) { 239 assert(is_power_of_2(size), "Invalid size"); 240 const size_t mask = size - 1; 241 return (prev_index + 1) & mask; 242 } 243 244 bool ZNMethodTable::register_entry(ZNMethodTableEntry* table, size_t size, ZNMethodTableEntry entry) { 245 const nmethod* const nm = entry.method(); 246 size_t index = first_index(nm, size); 247 248 for (;;) { 249 const ZNMethodTableEntry table_entry = table[index]; 250 251 if (!table_entry.registered() && !table_entry.unregistered()) { 252 // Insert new entry 253 table[index] = entry; 254 return true; 255 } 256 257 if (table_entry.registered() && table_entry.method() == nm) { 258 // Replace existing entry 259 table[index] = entry; 260 return false; 261 } 262 263 index = next_index(index, size); 264 } 265 } 266 267 void ZNMethodTable::unregister_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) { 268 if (size == 0) { 269 // Table is empty 270 return; 271 } 272 273 size_t index = first_index(nm, size); 274 275 for (;;) { 276 const ZNMethodTableEntry table_entry = table[index]; 277 assert(table_entry.registered() || table_entry.unregistered(), "Entry not found"); 278 279 if (table_entry.registered() && table_entry.method() == nm) { 280 // Remove entry 281 table[index] = ZNMethodTableEntry(true /* unregistered */); 282 283 // Destroy GC data 284 ZNMethodData::destroy(gc_data(nm)); 285 set_gc_data(nm, NULL); 286 return; 287 } 288 289 index = next_index(index, size); 290 } 291 } 292 293 void ZNMethodTable::rebuild(size_t new_size) { 294 ZLocker<ZLock> locker(&_iter_lock); 295 assert(is_power_of_2(new_size), "Invalid size"); 296 297 log_debug(gc, nmethod)("Rebuilding NMethod Table: " 298 SIZE_FORMAT "->" SIZE_FORMAT " entries, " 299 SIZE_FORMAT "(%.0lf%%->%.0lf%%) registered, " 300 SIZE_FORMAT "(%.0lf%%->%.0lf%%) unregistered", 301 _size, new_size, 302 _nregistered, percent_of(_nregistered, _size), percent_of(_nregistered, new_size), 303 _nunregistered, percent_of(_nunregistered, _size), 0.0); 304 305 // Allocate new table 306 ZNMethodTableEntry* const new_table = new ZNMethodTableEntry[new_size]; 307 308 // Transfer all registered entries 309 for (size_t i = 0; i < _size; i++) { 310 const ZNMethodTableEntry entry = _table[i]; 311 if (entry.registered()) { 312 register_entry(new_table, new_size, entry); 313 } 314 } 315 316 if (_iter_table != _table) { 317 // Delete old table 318 delete [] _table; 319 } 320 321 // Install new table 322 _table = new_table; 323 _size = new_size; 324 _nunregistered = 0; 325 } 326 327 void ZNMethodTable::rebuild_if_needed() { 328 // The hash table uses linear probing. To avoid wasting memory while 329 // at the same time maintaining good hash collision behavior we want 330 // to keep the table occupancy between 30% and 70%. The table always 331 // grows/shrinks by doubling/halving its size. Pruning of unregistered 332 // entries is done by rebuilding the table with or without resizing it. 333 const size_t min_size = 1024; 334 const size_t shrink_threshold = _size * 0.30; 335 const size_t prune_threshold = _size * 0.65; 336 const size_t grow_threshold = _size * 0.70; 337 338 if (_size == 0) { 339 // Initialize table 340 rebuild(min_size); 341 } else if (_nregistered < shrink_threshold && _size > min_size) { 342 // Shrink table 343 rebuild(_size / 2); 344 } else if (_nregistered + _nunregistered > grow_threshold) { 345 // Prune or grow table 346 if (_nregistered < prune_threshold) { 347 // Prune table 348 rebuild(_size); 349 } else { 350 // Grow table 351 rebuild(_size * 2); 352 } 353 } 354 } 355 356 void ZNMethodTable::log_register(const nmethod* nm, ZNMethodTableEntry entry) { 357 LogTarget(Trace, gc, nmethod) log; 358 if (!log.is_enabled()) { 359 return; 360 } 361 362 log.print("Register NMethod: %s.%s (" PTR_FORMAT "), " 363 "Compiler: %s, Oops: %d, ImmediateOops: " SIZE_FORMAT ", NonImmediateOops: %s", 364 nm->method()->method_holder()->external_name(), 365 nm->method()->name()->as_C_string(), 366 p2i(nm), 367 nm->compiler_name(), 368 nm->oops_count() - 1, 369 entry.immediate_oops() ? gc_data(nm)->immediate_oops()->immediate_oops_count() : 0, 370 entry.non_immediate_oops() ? "Yes" : "No"); 371 372 LogTarget(Trace, gc, nmethod, oops) log_oops; 373 if (!log_oops.is_enabled()) { 374 return; 375 } 376 377 // Print nmethod oops table 378 oop* const begin = nm->oops_begin(); 379 oop* const end = nm->oops_end(); 380 for (oop* p = begin; p < end; p++) { 381 log_oops.print(" Oop[" SIZE_FORMAT "] " PTR_FORMAT " (%s)", 382 (p - begin), p2i(*p), (*p)->klass()->external_name()); 383 } 384 385 if (entry.immediate_oops()) { 386 // Print nmethod immediate oops 387 const ZNMethodDataImmediateOops* const nmi = gc_data(nm)->immediate_oops(); 388 if (nmi != NULL) { 389 oop** const begin = nmi->immediate_oops_begin(); 390 oop** const end = nmi->immediate_oops_end(); 391 for (oop** p = begin; p < end; p++) { 392 log_oops.print(" ImmediateOop[" SIZE_FORMAT "] " PTR_FORMAT " @ " PTR_FORMAT " (%s)", 393 (p - begin), p2i(**p), p2i(*p), (**p)->klass()->external_name()); 394 } 395 } 396 } 397 } 398 399 void ZNMethodTable::log_unregister(const nmethod* nm) { 400 LogTarget(Debug, gc, nmethod) log; 401 if (!log.is_enabled()) { 402 return; 403 } 404 405 log.print("Unregister NMethod: %s.%s (" PTR_FORMAT ")", 406 nm->method()->method_holder()->external_name(), 407 nm->method()->name()->as_C_string(), 408 p2i(nm)); 409 } 410 411 size_t ZNMethodTable::registered_nmethods() { 412 return _nregistered; 413 } 414 415 size_t ZNMethodTable::unregistered_nmethods() { 416 return _nunregistered; 417 } 418 419 void ZNMethodTable::register_nmethod(nmethod* nm) { 420 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 421 ResourceMark rm; 422 423 // Grow/Shrink/Prune table if needed 424 rebuild_if_needed(); 425 426 // Create entry 427 const ZNMethodTableEntry entry = create_entry(nm); 428 429 log_register(nm, entry); 430 431 // Insert new entry 432 if (register_entry(_table, _size, entry)) { 433 // New entry registered. When register_entry() instead returns 434 // false the nmethod was already in the table so we do not want 435 // to increase number of registered entries in that case. 436 _nregistered++; 437 } 438 439 // Disarm nmethod entry barrier 440 disarm_nmethod(nm); 441 } 442 443 void ZNMethodTable::sweeper_wait_for_iteration() { 444 // The sweeper must wait for any ongoing iteration to complete 445 // before it can unregister an nmethod. 446 if (!Thread::current()->is_Code_cache_sweeper_thread()) { 447 return; 448 } 449 450 while (_iter_table != NULL) { 451 MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 452 os::naked_short_sleep(1); 453 } 454 } 455 456 void ZNMethodTable::unregister_nmethod(nmethod* nm) { 457 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 458 ResourceMark rm; 459 460 sweeper_wait_for_iteration(); 461 462 log_unregister(nm); 463 464 // Remove entry 465 unregister_entry(_table, _size, nm); 466 _nunregistered++; 467 _nregistered--; 468 } 469 470 void ZNMethodTable::disarm_nmethod(nmethod* nm) { 471 BarrierSetNMethod* const bs = BarrierSet::barrier_set()->barrier_set_nmethod(); 472 if (bs != NULL) { 473 bs->disarm(nm); 474 } 475 } 476 477 void ZNMethodTable::nmethod_entries_do_begin() { 478 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 479 ZLocker<ZLock> locker(&_iter_lock); 480 481 // Prepare iteration 482 _iter_table = _table; 483 _iter_table_size = _size; 484 _claimed = 0; 485 assert(_iter_deferred_deletes.is_empty(), "Should be emtpy"); 486 } 487 488 void ZNMethodTable::nmethod_entries_do_end() { 489 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 490 ZLocker<ZLock> locker(&_iter_lock); 491 492 // Finish iteration 493 if (_iter_table != _table) { 494 delete [] _iter_table; 495 } 496 _iter_table = NULL; 497 assert(_claimed >= _iter_table_size, "Failed to claim all table entries"); 498 499 // Process deferred deletes 500 ZArrayIterator<void*> iter(&_iter_deferred_deletes); 501 for (void* data; iter.next(&data);) { 502 FREE_C_HEAP_ARRAY(uint8_t, data); 503 } 504 _iter_deferred_deletes.clear(); 505 } 506 507 void ZNMethodTable::entry_oops_do(ZNMethodTableEntry entry, OopClosure* cl) { 508 nmethod* const nm = entry.method(); 509 510 // Process oops table 511 oop* const begin = nm->oops_begin(); 512 oop* const end = nm->oops_end(); 513 for (oop* p = begin; p < end; p++) { 514 if (*p != Universe::non_oop_word()) { 515 cl->do_oop(p); 516 } 517 } 518 519 // Process immediate oops 520 if (entry.immediate_oops()) { 521 const ZNMethodDataImmediateOops* const nmi = gc_data(nm)->immediate_oops(); 522 if (nmi != NULL) { 523 oop** const begin = nmi->immediate_oops_begin(); 524 oop** const end = nmi->immediate_oops_end(); 525 for (oop** p = begin; p < end; p++) { 526 if (**p != Universe::non_oop_word()) { 527 cl->do_oop(*p); 528 } 529 } 530 } 531 } 532 533 // Process non-immediate oops 534 if (entry.non_immediate_oops()) { 535 nmethod* const nm = entry.method(); 536 nm->fix_oop_relocations(); 537 } 538 } 539 540 class ZNMethodTableEntryToOopsDo : public ZNMethodTableEntryClosure { 541 private: 542 OopClosure* _cl; 543 544 public: 545 ZNMethodTableEntryToOopsDo(OopClosure* cl) : 546 _cl(cl) {} 547 548 void do_nmethod_entry(ZNMethodTableEntry entry) { 549 ZNMethodTable::entry_oops_do(entry, _cl); 550 } 551 }; 552 553 void ZNMethodTable::oops_do(OopClosure* cl) { 554 ZNMethodTableEntryToOopsDo entry_cl(cl); 555 nmethod_entries_do(&entry_cl); 556 } 557 558 void ZNMethodTable::nmethod_entries_do(ZNMethodTableEntryClosure* cl) { 559 for (;;) { 560 // Claim table partition. Each partition is currently sized to span 561 // two cache lines. This number is just a guess, but seems to work well. 562 const size_t partition_size = (ZCacheLineSize * 2) / sizeof(ZNMethodTableEntry); 563 const size_t partition_start = MIN2(Atomic::add(partition_size, &_claimed) - partition_size, _iter_table_size); 564 const size_t partition_end = MIN2(partition_start + partition_size, _iter_table_size); 565 if (partition_start == partition_end) { 566 // End of table 567 break; 568 } 569 570 // Process table partition 571 for (size_t i = partition_start; i < partition_end; i++) { 572 const ZNMethodTableEntry entry = _iter_table[i]; 573 if (entry.registered()) { 574 cl->do_nmethod_entry(entry); 575 } 576 } 577 } 578 } 579 580 class ZNMethodTableUnlinkClosure : public ZNMethodTableEntryClosure { 581 private: 582 bool _unloading_occurred; 583 volatile bool _failed; 584 585 void set_failed() { 586 Atomic::store(true, &_failed); 587 } 588 589 public: 590 ZNMethodTableUnlinkClosure(bool unloading_occurred) : 591 _unloading_occurred(unloading_occurred), 592 _failed(false) {} 593 594 virtual void do_nmethod_entry(ZNMethodTableEntry entry) { 595 if (failed()) { 596 return; 597 } 598 599 nmethod* const nm = entry.method(); 600 if (!nm->is_alive()) { 601 return; 602 } 603 604 ZLocker<ZReentrantLock> locker(ZNMethodTable::lock_for_nmethod(nm)); 605 606 if (nm->is_unloading()) { 607 // Unlinking of the dependencies must happen before the 608 // handshake separating unlink and purge. 609 nm->flush_dependencies(false /* delete_immediately */); 610 611 // We don't need to take the lock when unlinking nmethods from 612 // the Method, because it is only concurrently unlinked by 613 // the entry barrier, which acquires the per nmethod lock. 614 nm->unlink_from_method(false /* acquire_lock */); 615 return; 616 } 617 618 // Heal oops and disarm 619 ZNMethodOopClosure cl; 620 ZNMethodTable::entry_oops_do(entry, &cl); 621 ZNMethodTable::disarm_nmethod(nm); 622 623 // Clear compiled ICs and exception caches 624 if (!nm->unload_nmethod_caches(_unloading_occurred)) { 625 set_failed(); 626 } 627 } 628 629 bool failed() const { 630 return Atomic::load(&_failed); 631 } 632 }; 633 634 class ZNMethodTableUnlinkTask : public ZTask { 635 private: 636 ZNMethodTableUnlinkClosure _cl; 637 ICRefillVerifier* _verifier; 638 639 public: 640 ZNMethodTableUnlinkTask(bool unloading_occurred, ICRefillVerifier* verifier) : 641 ZTask("ZNMethodTableUnlinkTask"), 642 _cl(unloading_occurred), 643 _verifier(verifier) { 644 ZNMethodTable::nmethod_entries_do_begin(); 645 } 646 647 ~ZNMethodTableUnlinkTask() { 648 ZNMethodTable::nmethod_entries_do_end(); 649 } 650 651 virtual void work() { 652 ICRefillVerifierMark mark(_verifier); 653 ZNMethodTable::nmethod_entries_do(&_cl); 654 } 655 656 bool success() const { 657 return !_cl.failed(); 658 } 659 }; 660 661 void ZNMethodTable::unlink(ZWorkers* workers, bool unloading_occurred) { 662 for (;;) { 663 ICRefillVerifier verifier; 664 665 { 666 ZNMethodTableUnlinkTask task(unloading_occurred, &verifier); 667 workers->run_concurrent(&task); 668 if (task.success()) { 669 return; 670 } 671 } 672 673 // Cleaning failed because we ran out of transitional IC stubs, 674 // so we have to refill and try again. Refilling requires taking 675 // a safepoint, so we temporarily leave the suspendible thread set. 676 SuspendibleThreadSetLeaver sts; 677 InlineCacheBuffer::refill_ic_stubs(); 678 } 679 } 680 681 class ZNMethodTablePurgeClosure : public ZNMethodTableEntryClosure { 682 public: 683 virtual void do_nmethod_entry(ZNMethodTableEntry entry) { 684 nmethod* const nm = entry.method(); 685 if (nm->is_alive() && nm->is_unloading()) { 686 nm->make_unloaded(); 687 } 688 } 689 }; 690 691 class ZNMethodTablePurgeTask : public ZTask { 692 private: 693 ZNMethodTablePurgeClosure _cl; 694 695 public: 696 ZNMethodTablePurgeTask() : 697 ZTask("ZNMethodTablePurgeTask"), 698 _cl() { 699 ZNMethodTable::nmethod_entries_do_begin(); 700 } 701 702 ~ZNMethodTablePurgeTask() { 703 ZNMethodTable::nmethod_entries_do_end(); 704 } 705 706 virtual void work() { 707 ZNMethodTable::nmethod_entries_do(&_cl); 708 } 709 }; 710 711 void ZNMethodTable::purge(ZWorkers* workers) { 712 ZNMethodTablePurgeTask task; 713 workers->run_concurrent(&task); 714 } | 1 /* 2 * Copyright (c) 2017, 2019, 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 "code/relocInfo.hpp" 26 #include "code/nmethod.hpp" 27 #include "code/icBuffer.hpp" 28 #include "gc/shared/barrierSet.hpp" 29 #include "gc/shared/barrierSetNMethod.hpp" 30 #include "gc/z/zGlobals.hpp" 31 #include "gc/z/zHash.inline.hpp" 32 #include "gc/z/zLock.inline.hpp" 33 #include "gc/z/zNMethodAllocator.hpp" 34 #include "gc/z/zNMethodClosure.hpp" 35 #include "gc/z/zNMethodData.hpp" 36 #include "gc/z/zNMethodTable.hpp" 37 #include "gc/z/zNMethodTableEntry.hpp" 38 #include "gc/z/zNMethodTableIteration.hpp" 39 #include "gc/z/zOopClosures.inline.hpp" 40 #include "gc/z/zTask.hpp" 41 #include "gc/z/zWorkers.hpp" 42 #include "logging/log.hpp" 43 #include "memory/allocation.hpp" 44 #include "memory/resourceArea.hpp" 45 #include "runtime/atomic.hpp" 46 #include "runtime/orderAccess.hpp" 47 #include "utilities/debug.hpp" 48 49 ZNMethodTableEntry* ZNMethodTable::_table = NULL; 50 size_t ZNMethodTable::_size = 0; 51 size_t ZNMethodTable::_nregistered = 0; 52 size_t ZNMethodTable::_nunregistered = 0; 53 ZNMethodTableIteration ZNMethodTable::_iteration; 54 55 ZNMethodTableEntry* ZNMethodTable::create(size_t size) { 56 void* const mem = ZNMethodAllocator::allocate(size * sizeof(ZNMethodTableEntry)); 57 return ::new (mem) ZNMethodTableEntry[size]; 58 } 59 60 void ZNMethodTable::destroy(ZNMethodTableEntry* table) { 61 ZNMethodAllocator::free(table); 62 } 63 64 size_t ZNMethodTable::first_index(const nmethod* nm, size_t size) { 65 assert(is_power_of_2(size), "Invalid size"); 66 const size_t mask = size - 1; 67 const size_t hash = ZHash::address_to_uint32((uintptr_t)nm); 68 return hash & mask; 69 } 70 71 size_t ZNMethodTable::next_index(size_t prev_index, size_t size) { 72 assert(is_power_of_2(size), "Invalid size"); 73 const size_t mask = size - 1; 74 return (prev_index + 1) & mask; 75 } 76 77 bool ZNMethodTable::register_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) { 78 const ZNMethodTableEntry entry(nm); 79 size_t index = first_index(nm, size); 80 81 for (;;) { 82 const ZNMethodTableEntry table_entry = table[index]; 83 84 if (!table_entry.registered() && !table_entry.unregistered()) { 85 // Insert new entry 86 table[index] = entry; 87 return true; 88 } 89 90 if (table_entry.registered() && table_entry.method() == nm) { 91 // Replace existing entry 92 table[index] = entry; 93 return false; 94 } 95 96 index = next_index(index, size); 97 } 98 } 99 100 void ZNMethodTable::unregister_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) { 101 size_t index = first_index(nm, size); 102 103 for (;;) { 104 const ZNMethodTableEntry table_entry = table[index]; 105 assert(table_entry.registered() || table_entry.unregistered(), "Entry not found"); 106 107 if (table_entry.registered() && table_entry.method() == nm) { 108 // Remove entry 109 table[index] = ZNMethodTableEntry(true /* unregistered */); 110 return; 111 } 112 113 index = next_index(index, size); 114 } 115 } 116 117 void ZNMethodTable::rebuild(size_t new_size) { 118 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 119 120 assert(is_power_of_2(new_size), "Invalid size"); 121 122 log_debug(gc, nmethod)("Rebuilding NMethod Table: " 123 SIZE_FORMAT "->" SIZE_FORMAT " entries, " 124 SIZE_FORMAT "(%.0lf%%->%.0lf%%) registered, " 125 SIZE_FORMAT "(%.0lf%%->%.0lf%%) unregistered", 126 _size, new_size, 127 _nregistered, percent_of(_nregistered, _size), percent_of(_nregistered, new_size), 128 _nunregistered, percent_of(_nunregistered, _size), 0.0); 129 130 // Allocate new table 131 ZNMethodTableEntry* const new_table = ZNMethodTable::create(new_size); 132 133 // Transfer all registered entries 134 for (size_t i = 0; i < _size; i++) { 135 const ZNMethodTableEntry entry = _table[i]; 136 if (entry.registered()) { 137 register_entry(new_table, new_size, entry.method()); 138 } 139 } 140 141 // Free old table 142 ZNMethodTable::destroy(_table); 143 144 // Install new table 145 _table = new_table; 146 _size = new_size; 147 _nunregistered = 0; 148 } 149 150 void ZNMethodTable::rebuild_if_needed() { 151 // The hash table uses linear probing. To avoid wasting memory while 152 // at the same time maintaining good hash collision behavior we want 153 // to keep the table occupancy between 30% and 70%. The table always 154 // grows/shrinks by doubling/halving its size. Pruning of unregistered 155 // entries is done by rebuilding the table with or without resizing it. 156 const size_t min_size = 1024; 157 const size_t shrink_threshold = _size * 0.30; 158 const size_t prune_threshold = _size * 0.65; 159 const size_t grow_threshold = _size * 0.70; 160 161 if (_size == 0) { 162 // Initialize table 163 rebuild(min_size); 164 } else if (_nregistered < shrink_threshold && _size > min_size) { 165 // Shrink table 166 rebuild(_size / 2); 167 } else if (_nregistered + _nunregistered > grow_threshold) { 168 // Prune or grow table 169 if (_nregistered < prune_threshold) { 170 // Prune table 171 rebuild(_size); 172 } else { 173 // Grow table 174 rebuild(_size * 2); 175 } 176 } 177 } 178 179 size_t ZNMethodTable::registered_nmethods() { 180 return _nregistered; 181 } 182 183 size_t ZNMethodTable::unregistered_nmethods() { 184 return _nunregistered; 185 } 186 187 void ZNMethodTable::register_nmethod(nmethod* nm) { 188 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 189 190 // Grow/Shrink/Prune table if needed 191 rebuild_if_needed(); 192 193 // Insert new entry 194 if (register_entry(_table, _size, nm)) { 195 // New entry registered. When register_entry() instead returns 196 // false the nmethod was already in the table so we do not want 197 // to increase number of registered entries in that case. 198 _nregistered++; 199 } 200 } 201 202 void ZNMethodTable::wait_until_iteration_done() { 203 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 204 205 while (_iteration.in_progress()) { 206 CodeCache_lock->wait(Monitor::_no_safepoint_check_flag); 207 } 208 } 209 210 void ZNMethodTable::unregister_nmethod(nmethod* nm) { 211 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 212 213 // Remove entry 214 unregister_entry(_table, _size, nm); 215 _nunregistered++; 216 _nregistered--; 217 } 218 219 void ZNMethodTable::nmethods_do_begin() { 220 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 221 222 // Make sure we don't free data while iterating 223 ZNMethodAllocator::activate_deferred_frees(); 224 225 // Prepare iteration 226 _iteration.nmethods_do_begin(_table, _size); 227 } 228 229 void ZNMethodTable::nmethods_do_end() { 230 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 231 232 // Finish iteration 233 _iteration.nmethods_do_end(); 234 235 // Process deferred frees 236 ZNMethodAllocator::deactivate_and_process_deferred_frees(); 237 238 // Notify iteration done 239 CodeCache_lock->notify_all(); 240 } 241 242 void ZNMethodTable::nmethods_do(ZNMethodClosure* cl) { 243 _iteration.nmethods_do(cl); 244 } |