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/zNMethodTableIteration.hpp" 38 #include "gc/z/zOopClosures.inline.hpp" 39 #include "gc/z/zTask.hpp" 40 #include "gc/z/zWorkers.hpp" 41 #include "logging/log.hpp" 42 #include "memory/allocation.hpp" 43 #include "memory/resourceArea.hpp" 44 #include "runtime/atomic.hpp" 45 #include "runtime/orderAccess.hpp" 46 #include "utilities/debug.hpp" 47 48 ZNMethodTableEntry* ZNMethodTable::_table = NULL; 49 size_t ZNMethodTable::_size = 0; 50 size_t ZNMethodTable::_nregistered = 0; 51 size_t ZNMethodTable::_nunregistered = 0; 52 ZNMethodTableIteration ZNMethodTable::_iteration; 53 54 static ZNMethodData* gc_data(const nmethod* nm) { 55 return nm->gc_data<ZNMethodData>(); 56 } 57 58 static void set_gc_data(nmethod* nm, ZNMethodData* data) { 59 return nm->set_gc_data<ZNMethodData>(data); 60 } 61 62 ZNMethodTableEntry* ZNMethodTable::create(size_t size) { 63 void* const mem = ZNMethodAllocator::allocate(size * sizeof(ZNMethodTableEntry)); 64 return ::new (mem) ZNMethodTableEntry[size]; 65 } 66 67 void ZNMethodTable::destroy(ZNMethodTableEntry* table) { 68 ZNMethodAllocator::free(table); 69 } 70 71 void ZNMethodTable::attach_gc_data(nmethod* nm) { 72 GrowableArray<oop*> immediate_oops; 73 bool non_immediate_oops = false; 74 75 // Find all oops relocations 76 RelocIterator iter(nm); 77 while (iter.next()) { 78 if (iter.type() != relocInfo::oop_type) { 79 // Not an oop 80 continue; 81 } 82 83 oop_Relocation* r = iter.oop_reloc(); 84 85 if (!r->oop_is_immediate()) { 86 // Non-immediate oop found 87 non_immediate_oops = true; 88 continue; 89 } 90 91 if (r->oop_value() != NULL) { 92 // Non-NULL immediate oop found. NULL oops can safely be 93 // ignored since the method will be re-registered if they 94 // are later patched to be non-NULL. 95 immediate_oops.push(r->oop_addr()); 96 } 97 } 98 99 // Attach GC data to nmethod 100 ZNMethodData* data = gc_data(nm); 101 if (data == NULL) { 102 data = ZNMethodData::create(nm); 103 set_gc_data(nm, data); 104 } 105 106 // Attach oops in GC data 107 ZNMethodDataOops* const new_oops = ZNMethodDataOops::create(immediate_oops, non_immediate_oops); 108 ZNMethodDataOops* const old_oops = data->swap_oops(new_oops); 109 ZNMethodDataOops::destroy(old_oops); 110 } 111 112 void ZNMethodTable::detach_gc_data(nmethod* nm) { 113 // Destroy GC data 114 ZNMethodData::destroy(gc_data(nm)); 115 set_gc_data(nm, NULL); 116 } 117 118 ZReentrantLock* ZNMethodTable::lock_for_nmethod(nmethod* nm) { 119 ZNMethodData* const data = gc_data(nm); 120 if (data == NULL) { 121 return NULL; 122 } 123 return data->lock(); 124 } 125 126 size_t ZNMethodTable::first_index(const nmethod* nm, size_t size) { 127 assert(is_power_of_2(size), "Invalid size"); 128 const size_t mask = size - 1; 129 const size_t hash = ZHash::address_to_uint32((uintptr_t)nm); 130 return hash & mask; 131 } 132 133 size_t ZNMethodTable::next_index(size_t prev_index, size_t size) { 134 assert(is_power_of_2(size), "Invalid size"); 135 const size_t mask = size - 1; 136 return (prev_index + 1) & mask; 137 } 138 139 bool ZNMethodTable::register_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) { 140 const ZNMethodTableEntry entry(nm); 141 size_t index = first_index(nm, size); 142 143 for (;;) { 144 const ZNMethodTableEntry table_entry = table[index]; 145 146 if (!table_entry.registered() && !table_entry.unregistered()) { 147 // Insert new entry 148 table[index] = entry; 149 return true; 150 } 151 152 if (table_entry.registered() && table_entry.method() == nm) { 153 // Replace existing entry 154 table[index] = entry; 155 return false; 156 } 157 158 index = next_index(index, size); 159 } 160 } 161 162 void ZNMethodTable::unregister_entry(ZNMethodTableEntry* table, size_t size, nmethod* nm) { 163 size_t index = first_index(nm, size); 164 165 for (;;) { 166 const ZNMethodTableEntry table_entry = table[index]; 167 assert(table_entry.registered() || table_entry.unregistered(), "Entry not found"); 168 169 if (table_entry.registered() && table_entry.method() == nm) { 170 // Remove entry 171 table[index] = ZNMethodTableEntry(true /* unregistered */); 172 return; 173 } 174 175 index = next_index(index, size); 176 } 177 } 178 179 void ZNMethodTable::rebuild(size_t new_size) { 180 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 181 182 assert(is_power_of_2(new_size), "Invalid size"); 183 184 log_debug(gc, nmethod)("Rebuilding NMethod Table: " 185 SIZE_FORMAT "->" SIZE_FORMAT " entries, " 186 SIZE_FORMAT "(%.0lf%%->%.0lf%%) registered, " 187 SIZE_FORMAT "(%.0lf%%->%.0lf%%) unregistered", 188 _size, new_size, 189 _nregistered, percent_of(_nregistered, _size), percent_of(_nregistered, new_size), 190 _nunregistered, percent_of(_nunregistered, _size), 0.0); 191 192 // Allocate new table 193 ZNMethodTableEntry* const new_table = ZNMethodTable::create(new_size); 194 195 // Transfer all registered entries 196 for (size_t i = 0; i < _size; i++) { 197 const ZNMethodTableEntry entry = _table[i]; 198 if (entry.registered()) { 199 register_entry(new_table, new_size, entry.method()); 200 } 201 } 202 203 // Free old table 204 ZNMethodTable::destroy(_table); 205 206 // Install new table 207 _table = new_table; 208 _size = new_size; 209 _nunregistered = 0; 210 } 211 212 void ZNMethodTable::rebuild_if_needed() { 213 // The hash table uses linear probing. To avoid wasting memory while 214 // at the same time maintaining good hash collision behavior we want 215 // to keep the table occupancy between 30% and 70%. The table always 216 // grows/shrinks by doubling/halving its size. Pruning of unregistered 217 // entries is done by rebuilding the table with or without resizing it. 218 const size_t min_size = 1024; 219 const size_t shrink_threshold = _size * 0.30; 220 const size_t prune_threshold = _size * 0.65; 221 const size_t grow_threshold = _size * 0.70; 222 223 if (_size == 0) { 224 // Initialize table 225 rebuild(min_size); 226 } else if (_nregistered < shrink_threshold && _size > min_size) { 227 // Shrink table 228 rebuild(_size / 2); 229 } else if (_nregistered + _nunregistered > grow_threshold) { 230 // Prune or grow table 231 if (_nregistered < prune_threshold) { 232 // Prune table 233 rebuild(_size); 234 } else { 235 // Grow table 236 rebuild(_size * 2); 237 } 238 } 239 } 240 241 void ZNMethodTable::log_register(const nmethod* nm) { 242 LogTarget(Trace, gc, nmethod) log; 243 if (!log.is_enabled()) { 244 return; 245 } 246 247 const ZNMethodDataOops* const oops = gc_data(nm)->oops(); 248 249 log.print("Register NMethod: %s.%s (" PTR_FORMAT "), " 250 "Compiler: %s, Oops: %d, ImmediateOops: " SIZE_FORMAT ", NonImmediateOops: %s", 251 nm->method()->method_holder()->external_name(), 252 nm->method()->name()->as_C_string(), 253 p2i(nm), 254 nm->compiler_name(), 255 nm->oops_count() - 1, 256 oops->immediates_count(), 257 oops->has_non_immediates() ? "Yes" : "No"); 258 259 LogTarget(Trace, gc, nmethod, oops) log_oops; 260 if (!log_oops.is_enabled()) { 261 return; 262 } 263 264 // Print nmethod oops table 265 oop* const begin = nm->oops_begin(); 266 oop* const end = nm->oops_end(); 267 for (oop* p = begin; p < end; p++) { 268 log_oops.print(" Oop[" SIZE_FORMAT "] " PTR_FORMAT " (%s)", 269 (p - begin), p2i(*p), (*p)->klass()->external_name()); 270 } 271 272 // Print nmethod immediate oops 273 if (oops->immediates_count() > 0) { 274 oop** const begin = oops->immediates_begin(); 275 oop** const end = oops->immediates_end(); 276 for (oop** p = begin; p < end; p++) { 277 log_oops.print(" ImmediateOop[" SIZE_FORMAT "] " PTR_FORMAT " @ " PTR_FORMAT " (%s)", 278 (p - begin), p2i(**p), p2i(*p), (**p)->klass()->external_name()); 279 } 280 } 281 } 282 283 void ZNMethodTable::log_unregister(const nmethod* nm) { 284 LogTarget(Debug, gc, nmethod) log; 285 if (!log.is_enabled()) { 286 return; 287 } 288 289 log.print("Unregister NMethod: %s.%s (" PTR_FORMAT ")", 290 nm->method()->method_holder()->external_name(), 291 nm->method()->name()->as_C_string(), 292 p2i(nm)); 293 } 294 295 size_t ZNMethodTable::registered_nmethods() { 296 return _nregistered; 297 } 298 299 size_t ZNMethodTable::unregistered_nmethods() { 300 return _nunregistered; 301 } 302 303 void ZNMethodTable::register_nmethod(nmethod* nm) { 304 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 305 ResourceMark rm; 306 307 // Grow/Shrink/Prune table if needed 308 rebuild_if_needed(); 309 310 // Create and attach gc data 311 attach_gc_data(nm); 312 313 log_register(nm); 314 315 // Insert new entry 316 if (register_entry(_table, _size, nm)) { 317 // New entry registered. When register_entry() instead returns 318 // false the nmethod was already in the table so we do not want 319 // to increase number of registered entries in that case. 320 _nregistered++; 321 } 322 323 // Disarm nmethod entry barrier 324 disarm_nmethod(nm); 325 } 326 327 void ZNMethodTable::wait_until_iteration_done() { 328 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 329 330 while (_iteration.in_progress()) { 331 CodeCache_lock->wait(Monitor::_no_safepoint_check_flag); 332 } 333 } 334 335 void ZNMethodTable::unregister_nmethod(nmethod* nm) { 336 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 337 338 if (Thread::current()->is_Code_cache_sweeper_thread()) { 339 // The sweeper must wait for any ongoing iteration to complete 340 // before it can unregister an nmethod. 341 ZNMethodTable::wait_until_iteration_done(); 342 } 343 344 ResourceMark rm; 345 346 log_unregister(nm); 347 348 // Remove entry 349 unregister_entry(_table, _size, nm); 350 _nunregistered++; 351 _nregistered--; 352 353 detach_gc_data(nm); 354 } 355 356 void ZNMethodTable::disarm_nmethod(nmethod* nm) { 357 BarrierSetNMethod* const bs = BarrierSet::barrier_set()->barrier_set_nmethod(); 358 if (bs != NULL) { 359 bs->disarm(nm); 360 } 361 } 362 363 void ZNMethodTable::nmethods_do_begin() { 364 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 365 366 // Make sure we don't free data while iterating 367 ZNMethodAllocator::activate_deferred_frees(); 368 369 // Prepare iteration 370 _iteration.nmethods_do_begin(_table, _size); 371 } 372 373 void ZNMethodTable::nmethods_do_end() { 374 MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag); 375 376 // Finish iteration 377 _iteration.nmethods_do_end(); 378 379 // Process deferred frees 380 ZNMethodAllocator::deactivate_and_process_deferred_frees(); 381 382 // Notify iteration done 383 CodeCache_lock->notify_all(); 384 } 385 386 void ZNMethodTable::oops_do(nmethod* nm, OopClosure* cl) { 387 // Process oops table 388 oop* const begin = nm->oops_begin(); 389 oop* const end = nm->oops_end(); 390 for (oop* p = begin; p < end; p++) { 391 if (*p != Universe::non_oop_word()) { 392 cl->do_oop(p); 393 } 394 } 395 396 ZNMethodDataOops* const oops = gc_data(nm)->oops(); 397 398 // Process immediate oops 399 if (oops->immediates_count() > 0) { 400 oop** const begin = oops->immediates_begin(); 401 oop** const end = oops->immediates_end(); 402 for (oop** p = begin; p < end; p++) { 403 if (**p != Universe::non_oop_word()) { 404 cl->do_oop(*p); 405 } 406 } 407 } 408 409 // Process non-immediate oops 410 if (oops->has_non_immediates()) { 411 nm->fix_oop_relocations(); 412 } 413 } 414 415 class ZNMethodToOopsDo : public ZNMethodClosure { 416 private: 417 OopClosure* _cl; 418 419 public: 420 ZNMethodToOopsDo(OopClosure* cl) : 421 _cl(cl) {} 422 423 void do_nmethod(nmethod* nm) { 424 ZNMethodTable::oops_do(nm, _cl); 425 } 426 }; 427 428 void ZNMethodTable::oops_do(OopClosure* cl) { 429 ZNMethodToOopsDo nm_cl(cl); 430 nmethods_do(&nm_cl); 431 } 432 433 void ZNMethodTable::nmethods_do(ZNMethodClosure* cl) { 434 _iteration.nmethods_do(cl); 435 } 436 437 class ZNMethodTableUnlinkClosure : public ZNMethodClosure { 438 private: 439 bool _unloading_occurred; 440 volatile bool _failed; 441 442 void set_failed() { 443 Atomic::store(true, &_failed); 444 } 445 446 public: 447 ZNMethodTableUnlinkClosure(bool unloading_occurred) : 448 _unloading_occurred(unloading_occurred), 449 _failed(false) {} 450 451 virtual void do_nmethod(nmethod* nm) { 452 if (failed()) { 453 return; 454 } 455 456 if (!nm->is_alive()) { 457 return; 458 } 459 460 ZLocker<ZReentrantLock> locker(ZNMethodTable::lock_for_nmethod(nm)); 461 462 if (nm->is_unloading()) { 463 // Unlinking of the dependencies must happen before the 464 // handshake separating unlink and purge. 465 nm->flush_dependencies(false /* delete_immediately */); 466 467 // We don't need to take the lock when unlinking nmethods from 468 // the Method, because it is only concurrently unlinked by 469 // the entry barrier, which acquires the per nmethod lock. 470 nm->unlink_from_method(false /* acquire_lock */); 471 return; 472 } 473 474 // Heal oops and disarm 475 ZNMethodOopClosure cl; 476 ZNMethodTable::oops_do(nm, &cl); 477 ZNMethodTable::disarm_nmethod(nm); 478 479 // Clear compiled ICs and exception caches 480 if (!nm->unload_nmethod_caches(_unloading_occurred)) { 481 set_failed(); 482 } 483 } 484 485 bool failed() const { 486 return Atomic::load(&_failed); 487 } 488 }; 489 490 class ZNMethodTableUnlinkTask : public ZTask { 491 private: 492 ZNMethodTableUnlinkClosure _cl; 493 ICRefillVerifier* _verifier; 494 495 public: 496 ZNMethodTableUnlinkTask(bool unloading_occurred, ICRefillVerifier* verifier) : 497 ZTask("ZNMethodTableUnlinkTask"), 498 _cl(unloading_occurred), 499 _verifier(verifier) { 500 ZNMethodTable::nmethods_do_begin(); 501 } 502 503 ~ZNMethodTableUnlinkTask() { 504 ZNMethodTable::nmethods_do_end(); 505 } 506 507 virtual void work() { 508 ICRefillVerifierMark mark(_verifier); 509 ZNMethodTable::nmethods_do(&_cl); 510 } 511 512 bool success() const { 513 return !_cl.failed(); 514 } 515 }; 516 517 void ZNMethodTable::unlink(ZWorkers* workers, bool unloading_occurred) { 518 for (;;) { 519 ICRefillVerifier verifier; 520 521 { 522 ZNMethodTableUnlinkTask task(unloading_occurred, &verifier); 523 workers->run_concurrent(&task); 524 if (task.success()) { 525 return; 526 } 527 } 528 529 // Cleaning failed because we ran out of transitional IC stubs, 530 // so we have to refill and try again. Refilling requires taking 531 // a safepoint, so we temporarily leave the suspendible thread set. 532 SuspendibleThreadSetLeaver sts; 533 InlineCacheBuffer::refill_ic_stubs(); 534 } 535 } 536 537 class ZNMethodTablePurgeClosure : public ZNMethodClosure { 538 public: 539 virtual void do_nmethod(nmethod* nm) { 540 if (nm->is_alive() && nm->is_unloading()) { 541 nm->make_unloaded(); 542 } 543 } 544 }; 545 546 class ZNMethodTablePurgeTask : public ZTask { 547 private: 548 ZNMethodTablePurgeClosure _cl; 549 550 public: 551 ZNMethodTablePurgeTask() : 552 ZTask("ZNMethodTablePurgeTask"), 553 _cl() { 554 ZNMethodTable::nmethods_do_begin(); 555 } 556 557 ~ZNMethodTablePurgeTask() { 558 ZNMethodTable::nmethods_do_end(); 559 } 560 561 virtual void work() { 562 ZNMethodTable::nmethods_do(&_cl); 563 } 564 }; 565 566 void ZNMethodTable::purge(ZWorkers* workers) { 567 ZNMethodTablePurgeTask task; 568 workers->run_concurrent(&task); 569 }