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/compiledIC.hpp" 26 #include "code/relocInfo.hpp" 27 #include "code/nativeInst.hpp" 28 #include "code/nmethod.hpp" 29 #include "gc/z/zGlobals.hpp" 30 #include "gc/z/zHash.inline.hpp" 31 #include "gc/z/zLock.inline.hpp" 32 #include "gc/z/zNMethodTable.hpp" 33 #include "gc/z/zOopClosures.inline.hpp" 34 #include "gc/z/zTask.hpp" 35 #include "gc/z/zWorkers.hpp" 36 #include "logging/log.hpp" 37 #include "memory/allocation.inline.hpp" 38 #include "memory/resourceArea.hpp" 39 #include "oops/oop.inline.hpp" 40 #include "runtime/atomic.hpp" 41 #include "utilities/debug.hpp" 42 #include "utilities/spinYield.hpp" 43 44 class ZNMethodWithImmediateOops { 45 private: 46 nmethod* const _nm; 47 const size_t _nimmediate_oops; 48 49 static size_t header_size(); 50 51 ZNMethodWithImmediateOops(nmethod* nm, const GrowableArray<oop*>& immediate_oops); 52 53 public: 54 static ZNMethodWithImmediateOops* create(nmethod* nm, const GrowableArray<oop*>& immediate_oops); 55 static void destroy(ZNMethodWithImmediateOops* nmi); 56 57 nmethod* method() const; 58 size_t immediate_oops_count() const; 59 oop** immediate_oops_begin() const; 60 oop** immediate_oops_begin_safe() const; 61 oop** immediate_oops_end() const; 62 }; 63 64 size_t ZNMethodWithImmediateOops::header_size() { 65 const size_t size = sizeof(ZNMethodWithImmediateOops); 66 assert(is_aligned(size, sizeof(oop*)), "Header misaligned"); 67 return size; 68 } 69 70 ZNMethodWithImmediateOops::ZNMethodWithImmediateOops(nmethod* nm, const GrowableArray<oop*>& immediate_oops) : 71 _nm(nm), 72 _nimmediate_oops(immediate_oops.length()) { 73 // Save all immediate oops 74 for (size_t i = 0; i < _nimmediate_oops; i++) { 75 immediate_oops_begin()[i] = immediate_oops.at(i); 76 } 77 } 78 79 ZNMethodWithImmediateOops* ZNMethodWithImmediateOops::create(nmethod* nm, const GrowableArray<oop*>& immediate_oops) { 80 // Allocate memory for the ZNMethodWithImmediateOops object 81 // plus the immediate oop* array that follows right after. 82 const size_t size = header_size() + (sizeof(oop*) * immediate_oops.length()); 83 void* const method_with_immediate_oops = NEW_C_HEAP_ARRAY(uint8_t, size, mtGC); 84 return ::new (method_with_immediate_oops) ZNMethodWithImmediateOops(nm, immediate_oops); 85 } 86 87 void ZNMethodWithImmediateOops::destroy(ZNMethodWithImmediateOops* nmi) { 88 FREE_C_HEAP_ARRAY(uint8_t, nmi); 89 } 90 91 nmethod* ZNMethodWithImmediateOops::method() const { 92 return _nm; 93 } 94 95 size_t ZNMethodWithImmediateOops::immediate_oops_count() const { 96 return _nimmediate_oops; 97 } 98 99 oop** ZNMethodWithImmediateOops::immediate_oops_begin() const { 100 // The immediate oop* array starts immediately after this object 101 return (oop**)((uintptr_t)this + header_size()); 102 } 103 104 oop** ZNMethodWithImmediateOops::immediate_oops_begin_safe() const { 105 // Non-entrant nmethods have a jump instruction patched into the beginning 106 // of the verified entry point, which could have overwritten an immediate 107 // oop. If so, make sure we skip over that oop. 108 if (_nm->is_not_entrant()) { 109 oop* const first_immediate_oop = *immediate_oops_begin(); 110 oop* const safe_begin = (oop*)(_nm->verified_entry_point() + NativeJump::instruction_size); 111 if (first_immediate_oop < safe_begin) { 112 // First immediate oop overwritten, skip it 113 return immediate_oops_begin() + 1; 114 } 115 } 116 117 // First immediate oop not overwritten 118 return immediate_oops_begin(); 119 } 120 121 122 oop** ZNMethodWithImmediateOops::immediate_oops_end() const { 123 return immediate_oops_begin() + immediate_oops_count(); 124 } 125 126 ZLock ZNMethodTable::_rebuild_lock; 127 ZNMethodTableEntry* ZNMethodTable::_table = NULL; 128 ZNMethodTableEntry* ZNMethodTable::_scanned_table = NULL; 129 size_t ZNMethodTable::_size = 0; 130 size_t ZNMethodTable::_scanned_table_size = 0; 131 size_t ZNMethodTable::_nregistered = 0; 132 size_t ZNMethodTable::_nunregistered = 0; 133 volatile size_t ZNMethodTable::_claimed = 0; 134 135 ZNMethodTableEntry ZNMethodTable::create_entry(nmethod* nm) { 136 GrowableArray<oop*> immediate_oops; 137 bool non_immediate_oops = false; 138 139 // Find all oops relocations 140 RelocIterator iter(nm); 141 while (iter.next()) { 142 if (iter.type() != relocInfo::oop_type) { 143 // Not an oop 144 continue; 145 } 146 147 oop_Relocation* r = iter.oop_reloc(); 148 149 if (!r->oop_is_immediate()) { 150 // Non-immediate oop found 151 non_immediate_oops = true; 152 continue; 153 } 154 155 if (r->oop_value() != NULL) { 156 // Non-NULL immediate oop found. NULL oops can safely be 157 // ignored since the method will be re-registered if they 158 // are later patched to be non-NULL. 159 immediate_oops.push(r->oop_addr()); 160 } 161 } 162 163 // oops_count() returns the number of oops in the oop table plus one 164 if (immediate_oops.is_empty() && nm->oops_count() == 1) { 165 // No oops found, but return any entry anyway 166 return ZNMethodTableEntry(nm, non_immediate_oops); 167 } 168 169 if (immediate_oops.is_empty()) { 170 // No immediate oops found, return entry without immediate oops 171 return ZNMethodTableEntry(nm, non_immediate_oops); 172 } 173 174 // Return entry with immediate oops 175 return ZNMethodTableEntry(ZNMethodWithImmediateOops::create(nm, immediate_oops), non_immediate_oops); 176 } 177 178 void ZNMethodTable::destroy_entry(ZNMethodTableEntry entry) { 179 if (entry.immediate_oops()) { 180 ZNMethodWithImmediateOops::destroy(entry.method_with_immediate_oops()); 181 } 182 } 183 184 nmethod* ZNMethodTable::method(ZNMethodTableEntry entry) { 185 return entry.immediate_oops() ? entry.method_with_immediate_oops()->method() : entry.method(); 186 } 187 188 size_t ZNMethodTable::first_index(const nmethod* nm, size_t size) { 189 assert(is_power_of_2(size), "Invalid size"); 190 const size_t mask = size - 1; 191 const size_t hash = ZHash::address_to_uint32((uintptr_t)nm); 192 return hash & mask; 193 } 194 195 size_t ZNMethodTable::next_index(size_t prev_index, size_t size) { 196 assert(is_power_of_2(size), "Invalid size"); 197 const size_t mask = size - 1; 198 return (prev_index + 1) & mask; 199 } 200 201 bool ZNMethodTable::register_entry(ZNMethodTableEntry* table, size_t size, ZNMethodTableEntry entry) { 202 const nmethod* const nm = method(entry); 203 size_t index = first_index(nm, size); 204 205 for (;;) { 206 const ZNMethodTableEntry table_entry = table[index]; 207 208 if (!table_entry.registered() && !table_entry.unregistered()) { 209 // Insert new entry 210 table[index] = entry; 211 return true; 212 } 213 214 if (table_entry.registered() && method(table_entry) == nm) { 215 // Replace existing entry 216 destroy_entry(table_entry); 217 table[index] = entry; 218 return false; 219 } 220 221 index = next_index(index, size); 222 } 223 } 224 225 bool ZNMethodTable::unregister_entry(ZNMethodTableEntry* table, size_t size, const nmethod* nm) { 226 if (size == 0) { 227 // Table is empty 228 return false; 229 } 230 231 size_t index = first_index(nm, size); 232 233 for (;;) { 234 const ZNMethodTableEntry table_entry = table[index]; 235 236 if (!table_entry.registered() && !table_entry.unregistered()) { 237 // Entry not found 238 return false; 239 } 240 241 if (table_entry.registered() && method(table_entry) == nm) { 242 // Remove entry 243 destroy_entry(table_entry); 244 table[index] = ZNMethodTableEntry(true /* unregistered */); 245 return true; 246 } 247 248 index = next_index(index, size); 249 } 250 } 251 252 void ZNMethodTable::rebuild(size_t new_size) { 253 ZLocker m(&_rebuild_lock); 254 assert(is_power_of_2(new_size), "Invalid size"); 255 256 log_debug(gc, nmethod)("Rebuilding NMethod Table: " 257 SIZE_FORMAT "->" SIZE_FORMAT " entries, " 258 SIZE_FORMAT "(%.0lf%%->%.0lf%%) registered, " 259 SIZE_FORMAT "(%.0lf%%->%.0lf%%) unregistered", 260 _size, new_size, 261 _nregistered, percent_of(_nregistered, _size), percent_of(_nregistered, new_size), 262 _nunregistered, percent_of(_nunregistered, _size), 0.0); 263 264 // Allocate new table 265 ZNMethodTableEntry* const new_table = new ZNMethodTableEntry[new_size]; 266 267 // Transfer all registered entries 268 for (size_t i = 0; i < _size; i++) { 269 const ZNMethodTableEntry entry = _table[i]; 270 if (entry.registered()) { 271 register_entry(new_table, new_size, entry); 272 } 273 } 274 275 if (_table != _scanned_table) { 276 // Delete old table 277 delete [] _table; 278 } 279 280 // Install new table 281 _table = new_table; 282 _size = new_size; 283 _nunregistered = 0; 284 } 285 286 void ZNMethodTable::rebuild_if_needed() { 287 // The hash table uses linear probing. To avoid wasting memory while 288 // at the same time maintaining good hash collision behavior we want 289 // to keep the table occupancy between 30% and 70%. The table always 290 // grows/shrinks by doubling/halving its size. Pruning of unregistered 291 // entries is done by rebuilding the table with or without resizing it. 292 const size_t min_size = 1024; 293 const size_t shrink_threshold = _size * 0.30; 294 const size_t prune_threshold = _size * 0.65; 295 const size_t grow_threshold = _size * 0.70; 296 297 if (_size == 0) { 298 // Initialize table 299 rebuild(min_size); 300 } else if (_nregistered < shrink_threshold && _size > min_size) { 301 // Shrink table 302 rebuild(_size / 2); 303 } else if (_nregistered + _nunregistered > grow_threshold) { 304 // Prune or grow table 305 if (_nregistered < prune_threshold) { 306 // Prune table 307 rebuild(_size); 308 } else { 309 // Grow table 310 rebuild(_size * 2); 311 } 312 } 313 } 314 315 void ZNMethodTable::log_register(const nmethod* nm, ZNMethodTableEntry entry) { 316 LogTarget(Trace, gc, nmethod) log; 317 if (!log.is_enabled()) { 318 return; 319 } 320 321 log.print("Register NMethod: %s.%s (" PTR_FORMAT "), " 322 "Compiler: %s, Oops: %d, ImmediateOops: " SIZE_FORMAT ", NonImmediateOops: %s", 323 nm->method()->method_holder()->external_name(), 324 nm->method()->name()->as_C_string(), 325 p2i(nm), 326 nm->compiler_name(), 327 nm->oops_count() - 1, 328 entry.immediate_oops() ? entry.method_with_immediate_oops()->immediate_oops_count() : 0, 329 BOOL_TO_STR(entry.non_immediate_oops())); 330 331 LogTarget(Trace, gc, nmethod, oops) log_oops; 332 if (!log_oops.is_enabled()) { 333 return; 334 } 335 336 // Print nmethod oops table 337 oop* const begin = nm->oops_begin(); 338 oop* const end = nm->oops_end(); 339 for (oop* p = begin; p < end; p++) { 340 log_oops.print(" Oop[" SIZE_FORMAT "] " PTR_FORMAT " (%s)", 341 (p - begin), p2i(*p), (*p)->klass()->external_name()); 342 } 343 344 if (entry.immediate_oops()) { 345 // Print nmethod immediate oops 346 const ZNMethodWithImmediateOops* const nmi = entry.method_with_immediate_oops(); 347 if (nmi != NULL) { 348 oop** const begin = nmi->immediate_oops_begin(); 349 oop** const end = nmi->immediate_oops_end(); 350 for (oop** p = begin; p < end; p++) { 351 log_oops.print(" ImmediateOop[" SIZE_FORMAT "] " PTR_FORMAT " @ " PTR_FORMAT " (%s)", 352 (p - begin), p2i(**p), p2i(*p), (**p)->klass()->external_name()); 353 } 354 } 355 } 356 } 357 358 void ZNMethodTable::log_unregister(const nmethod* nm) { 359 LogTarget(Debug, gc, nmethod) log; 360 if (!log.is_enabled()) { 361 return; 362 } 363 364 log.print("Unregister NMethod: %s.%s (" PTR_FORMAT ")", 365 nm->method()->method_holder()->external_name(), 366 nm->method()->name()->as_C_string(), 367 p2i(nm)); 368 } 369 370 size_t ZNMethodTable::registered_nmethods() { 371 return _nregistered; 372 } 373 374 size_t ZNMethodTable::unregistered_nmethods() { 375 return _nunregistered; 376 } 377 378 void ZNMethodTable::register_nmethod(nmethod* nm) { 379 ResourceMark rm; 380 381 nm->disarm_barrier(); 382 383 // Create entry 384 const ZNMethodTableEntry entry = create_entry(nm); 385 386 log_register(nm, entry); 387 388 if (!entry.registered()) { 389 // Method doesn't have any oops, ignore it 390 return; 391 } 392 393 // Grow/Shrink/Prune table if needed 394 rebuild_if_needed(); 395 396 // Insert new entry 397 if (register_entry(_table, _size, entry)) { 398 // New entry registered. When register_entry() instead returns 399 // false the nmethod was already in the table so we do not want 400 // to increase number of registered entries in that case. 401 _nregistered++; 402 } 403 } 404 405 void ZNMethodTable::unregister_nmethod(nmethod* nm) { 406 ResourceMark rm; 407 408 log_unregister(nm); 409 410 if (CodeCache_lock->owned_by_self()) { 411 SpinYield yield; 412 // Entering from the sweeper; prevent it from deleting concurrently scanned nmethods 413 while (_scanned_table != NULL) { 414 MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 415 yield.wait(); 416 } 417 } 418 419 // Remove entry 420 if (unregister_entry(_table, _size, nm)) { 421 // Entry was unregistered. When unregister_entry() instead returns 422 // false the nmethod was not in the table (because it didn't have 423 // any oops) so we do not want to decrease the number of registered 424 // entries in that case. 425 _nregistered--; 426 _nunregistered++; 427 } 428 } 429 430 void ZNMethodTable::gc_prologue() { 431 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 432 ZLocker m(&_rebuild_lock); 433 _scanned_table = _table; 434 _scanned_table_size = _size; 435 _claimed = 0; 436 } 437 438 void ZNMethodTable::gc_epilogue() { 439 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 440 ZLocker m(&_rebuild_lock); 441 if (_scanned_table != _table) { 442 delete [] _scanned_table; 443 } 444 _scanned_table = NULL; 445 assert(_claimed >= _scanned_table_size, "Failed to claim all table entries"); 446 } 447 448 void ZNMethodTable::entry_oops_do(ZNMethodTableEntry* entry, OopClosure* cl) { 449 entry_oops_do_no_fixup(entry, cl); 450 if (entry->non_immediate_oops()) { 451 // Process non-immediate oops 452 nmethod* const nm = method(*entry); 453 nm->fix_oop_relocations(); 454 } 455 } 456 457 void ZNMethodTable::entry_oops_do_no_fixup(ZNMethodTableEntry* entry, OopClosure* cl) { 458 nmethod* const nm = ZNMethodTable::method(*entry); 459 if (!nm->is_alive()) { 460 // No need to visit oops 461 return; 462 } 463 464 // Process oops table 465 oop* const begin = nm->oops_begin(); 466 oop* const end = nm->oops_end(); 467 for (oop* p = begin; p < end; p++) { 468 if (*p != Universe::non_oop_word()) { 469 cl->do_oop(p); 470 } 471 } 472 473 if (entry->immediate_oops()) { 474 // Process immediate oops 475 const ZNMethodWithImmediateOops* const nmi = entry->method_with_immediate_oops(); 476 if (nmi != NULL) { 477 oop** const begin = nmi->immediate_oops_begin_safe(); 478 oop** const end = nmi->immediate_oops_end(); 479 for (oop** p = begin; p < end; p++) { 480 cl->do_oop(*p); 481 } 482 } 483 } 484 } 485 486 class ZNMethodTableEntryToOopsDo : public ZNMethodTableEntryClosure { 487 private: 488 OopClosure* _cl; 489 490 public: 491 ZNMethodTableEntryToOopsDo(OopClosure* cl) : _cl(cl) {} 492 493 void do_nmethod_entry(ZNMethodTableEntry* entry) { 494 ZNMethodTable::entry_oops_do(entry, _cl); 495 } 496 }; 497 498 void ZNMethodTable::oops_do(OopClosure* cl) { 499 ZNMethodTableEntryToOopsDo entry_cl(cl); 500 nmethod_entries_do(&entry_cl); 501 } 502 503 void ZNMethodTable::nmethod_entries_do(ZNMethodTableEntryClosure* cl) { 504 for (;;) { 505 // Claim table partition. Each partition is currently sized to span 506 // two cache lines. This number is just a guess, but seems to work well. 507 const size_t partition_size = (ZCacheLineSize * 2) / sizeof(ZNMethodTableEntry); 508 const size_t partition_start = MIN2(Atomic::add(partition_size, &_claimed) - partition_size, _scanned_table_size); 509 const size_t partition_end = MIN2(partition_start + partition_size, _scanned_table_size); 510 if (partition_start == partition_end) { 511 // End of table 512 break; 513 } 514 515 // Process table partition 516 for (size_t i = partition_start; i < partition_end; i++) { 517 ZNMethodTableEntry& entry = _scanned_table[i]; 518 if (entry.registered()) { 519 cl->do_nmethod_entry(&entry); 520 } 521 } 522 } 523 } 524 525 class ZNMethodTableUnloadClosure : public ZNMethodTableEntryClosure { 526 private: 527 bool _unloading_occurred; 528 529 public: 530 ZNMethodTableUnloadClosure(BoolObjectClosure* is_alive, bool unloading_occurred) 531 : ZNMethodTableEntryClosure(), 532 _unloading_occurred(unloading_occurred) {} 533 534 virtual void do_nmethod_entry(ZNMethodTableEntry* entry) { 535 nmethod* nm = ZNMethodTable::method(*entry); 536 if (!nm->is_alive()) { 537 return; 538 } 539 540 if (nm->is_unloading()) { 541 nm->make_unloaded(); 542 return; 543 } 544 545 ZPhantomKeepAliveOopClosure cl; 546 ZNMethodTable::entry_oops_do_no_fixup(entry, &cl); 547 ZNMethodBarrier::cleanup_nmethod_caches(nm, _unloading_occurred); 548 nm->disarm_barrier(); 549 } 550 }; 551 552 class ZNMethodTableUnloadTask : public ZTask { 553 private: 554 ZNMethodTableUnloadClosure _unlink_cl; 555 556 public: 557 ZNMethodTableUnloadTask(BoolObjectClosure* cl, bool unloading_occurred) 558 : ZTask("ZNMethodTableUnloadTask"), 559 _unlink_cl(cl, unloading_occurred) 560 { 561 ZNMethodTable::gc_prologue(); 562 } 563 564 ~ZNMethodTableUnloadTask() { 565 ZNMethodTable::gc_epilogue(); 566 } 567 568 virtual void work() { 569 ZNMethodTable::nmethod_entries_do(&_unlink_cl); 570 } 571 }; 572 573 void ZNMethodTable::do_unloading(ZWorkers* workers, BoolObjectClosure* is_alive, bool unloading_occurred) { 574 ZNMethodTableUnloadTask task(is_alive, unloading_occurred); 575 workers->run_concurrent(&task); 576 }