1 /* 2 * Copyright (c) 2019, 2020, Red Hat, Inc. 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 25 #include "precompiled.hpp" 26 27 #include "gc/shenandoah/shenandoahClosures.inline.hpp" 28 #include "gc/shenandoah/shenandoahConcurrentRoots.hpp" 29 #include "gc/shenandoah/shenandoahHeap.inline.hpp" 30 #include "gc/shenandoah/shenandoahNMethod.inline.hpp" 31 #include "memory/resourceArea.hpp" 32 33 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>& oops, bool non_immediate_oops) : 34 _nm(nm), _oops(NULL), _oops_count(0), _unregistered(false) { 35 36 if (!oops.is_empty()) { 37 _oops_count = oops.length(); 38 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC); 39 for (int c = 0; c < _oops_count; c++) { 40 _oops[c] = oops.at(c); 41 } 42 } 43 _has_non_immed_oops = non_immediate_oops; 44 45 assert_same_oops(); 46 } 47 48 ShenandoahNMethod::~ShenandoahNMethod() { 49 if (_oops != NULL) { 50 FREE_C_HEAP_ARRAY(oop*, _oops); 51 } 52 } 53 54 class ShenandoahHasCSetOopClosure : public OopClosure { 55 private: 56 ShenandoahHeap* const _heap; 57 bool _has_cset_oops; 58 59 public: 60 ShenandoahHasCSetOopClosure() : 61 _heap(ShenandoahHeap::heap()), 62 _has_cset_oops(false) { 63 } 64 65 bool has_cset_oops() const { 66 return _has_cset_oops; 67 } 68 69 void do_oop(oop* p) { 70 oop value = RawAccess<>::oop_load(p); 71 if (!_has_cset_oops && _heap->in_collection_set(value)) { 72 _has_cset_oops = true; 73 } 74 } 75 76 void do_oop(narrowOop* p) { 77 ShouldNotReachHere(); 78 } 79 }; 80 81 bool ShenandoahNMethod::has_cset_oops(ShenandoahHeap *heap) { 82 ShenandoahHasCSetOopClosure cl; 83 oops_do(&cl); 84 return cl.has_cset_oops(); 85 } 86 87 void ShenandoahNMethod::update() { 88 ResourceMark rm; 89 bool non_immediate_oops = false; 90 GrowableArray<oop*> oops; 91 92 detect_reloc_oops(nm(), oops, non_immediate_oops); 93 if (oops.length() != _oops_count) { 94 if (_oops != NULL) { 95 FREE_C_HEAP_ARRAY(oop*, _oops); 96 _oops = NULL; 97 } 98 99 _oops_count = oops.length(); 100 if (_oops_count > 0) { 101 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC); 102 } 103 } 104 105 for (int index = 0; index < _oops_count; index ++) { 106 _oops[index] = oops.at(index); 107 } 108 _has_non_immed_oops = non_immediate_oops; 109 110 assert_same_oops(); 111 } 112 113 void ShenandoahNMethod::oops_do(OopClosure* oops, bool fix_relocations) { 114 for (int c = 0; c < _oops_count; c ++) { 115 oop* p = _oops[c]; 116 if (*p != Universe::non_oop_word()) { 117 oops->do_oop(p); 118 } 119 } 120 121 oop* const begin = _nm->oops_begin(); 122 oop* const end = _nm->oops_end(); 123 for (oop* p = begin; p < end; p++) { 124 if (*p != Universe::non_oop_word()) { 125 oops->do_oop(p); 126 } 127 } 128 129 if (_has_non_immed_oops) { 130 _nm->fix_oop_relocations(); 131 } 132 } 133 134 void ShenandoahNMethod::detect_reloc_oops(nmethod* nm, GrowableArray<oop*>& oops, bool& has_non_immed_oops) { 135 has_non_immed_oops = false; 136 // Find all oops relocations 137 RelocIterator iter(nm); 138 while (iter.next()) { 139 if (iter.type() != relocInfo::oop_type) { 140 // Not an oop 141 continue; 142 } 143 144 oop_Relocation* r = iter.oop_reloc(); 145 if (!r->oop_is_immediate()) { 146 // Non-immediate oop found 147 has_non_immed_oops = true; 148 continue; 149 } 150 151 oop value = r->oop_value(); 152 if (value != NULL) { 153 oop* addr = r->oop_addr(); 154 shenandoah_assert_correct(addr, value); 155 shenandoah_assert_not_in_cset_except(addr, value, ShenandoahHeap::heap()->cancelled_gc()); 156 shenandoah_assert_not_forwarded(addr, value); 157 // Non-NULL immediate oop found. NULL oops can safely be 158 // ignored since the method will be re-registered if they 159 // are later patched to be non-NULL. 160 oops.push(addr); 161 } 162 } 163 } 164 165 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) { 166 ResourceMark rm; 167 bool non_immediate_oops = false; 168 GrowableArray<oop*> oops; 169 170 detect_reloc_oops(nm, oops, non_immediate_oops); 171 172 // No embedded oops 173 if(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading() && 174 oops.is_empty() && nm->oops_begin() >= nm->oops_end()) { 175 return NULL; 176 } 177 178 return new ShenandoahNMethod(nm, oops, non_immediate_oops); 179 } 180 181 void ShenandoahNMethod::heal_nmethod(nmethod* nm) { 182 assert(ShenandoahHeap::heap()->is_concurrent_root_in_progress(), "Only this phase"); 183 ShenandoahNMethod* data = gc_data(nm); 184 assert(data != NULL, "Sanity"); 185 assert(data->lock()->owned_by_self(), "Must hold the lock"); 186 187 ShenandoahEvacOOMScope evac_scope; 188 ShenandoahEvacuateUpdateRootsClosure<> cl; 189 data->oops_do(&cl, true /*fix relocation*/); 190 } 191 192 class ShenandoahKeepNMethodMetadataAliveClosure : public OopClosure { 193 private: 194 ShenandoahBarrierSet* const _bs; 195 const bool has_forwarded_objects; 196 public: 197 ShenandoahKeepNMethodMetadataAliveClosure() : 198 _bs(static_cast<ShenandoahBarrierSet*>(BarrierSet::barrier_set())), 199 has_forwarded_objects(ShenandoahHeap::heap()->has_forwarded_objects()) { 200 } 201 202 virtual void do_oop(oop* p) { 203 oop obj = RawAccess<>::oop_load(p); 204 if (!CompressedOops::is_null(obj)) { 205 if (has_forwarded_objects) { 206 obj = ShenandoahBarrierSet::resolve_forwarded_not_null(obj); 207 } 208 _bs->enqueue(obj); 209 } 210 } 211 212 virtual void do_oop(narrowOop* p) { 213 ShouldNotReachHere(); 214 } 215 }; 216 217 void ShenandoahNMethod::keep_metadata_alive(nmethod* nm) { 218 assert(ShenandoahHeap::heap()->is_concurrent_mark_in_progress(), "Only for marking"); 219 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 220 assert(data != NULL, "Must be"); 221 ShenandoahKeepNMethodMetadataAliveClosure cl; 222 data->oops_do(&cl); 223 } 224 225 #ifdef ASSERT 226 void ShenandoahNMethod::assert_alive_and_correct() { 227 assert(_nm->is_alive(), "only alive nmethods here"); 228 ShenandoahHeap* heap = ShenandoahHeap::heap(); 229 for (int c = 0; c < _oops_count; c++) { 230 oop *loc = _oops[c]; 231 assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*"); 232 oop o = RawAccess<>::oop_load(loc); 233 shenandoah_assert_correct_except(loc, o, o == NULL || heap->is_full_gc_move_in_progress()); 234 } 235 236 oop* const begin = _nm->oops_begin(); 237 oop* const end = _nm->oops_end(); 238 for (oop* p = begin; p < end; p++) { 239 if (*p != Universe::non_oop_word()) { 240 oop o = RawAccess<>::oop_load(p); 241 shenandoah_assert_correct_except(p, o, o == NULL || heap->is_full_gc_move_in_progress()); 242 } 243 } 244 } 245 246 class ShenandoahNMethodOopDetector : public OopClosure { 247 private: 248 ResourceMark rm; // For growable array allocation below. 249 GrowableArray<oop*> _oops; 250 251 public: 252 ShenandoahNMethodOopDetector() : _oops(10) {}; 253 254 void do_oop(oop* o) { 255 _oops.append(o); 256 } 257 void do_oop(narrowOop* o) { 258 fatal("NMethods should not have compressed oops embedded."); 259 } 260 261 GrowableArray<oop*>* oops() { 262 return &_oops; 263 } 264 265 bool has_oops() { 266 return !_oops.is_empty(); 267 } 268 }; 269 270 void ShenandoahNMethod::assert_same_oops(bool allow_dead) { 271 ShenandoahNMethodOopDetector detector; 272 nm()->oops_do(&detector, allow_dead); 273 274 GrowableArray<oop*>* oops = detector.oops(); 275 276 int count = _oops_count; 277 for (int index = 0; index < _oops_count; index ++) { 278 assert(oops->contains(_oops[index]), "Must contain this oop"); 279 } 280 281 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) { 282 if (*p == Universe::non_oop_word()) continue; 283 count++; 284 assert(oops->contains(p), "Must contain this oop"); 285 } 286 287 if (oops->length() < count) { 288 stringStream debug_stream; 289 debug_stream.print_cr("detected locs: %d", oops->length()); 290 for (int i = 0; i < oops->length(); i++) { 291 debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i))); 292 } 293 debug_stream.print_cr("recorded oops: %d", _oops_count); 294 for (int i = 0; i < _oops_count; i++) { 295 debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i])); 296 } 297 GrowableArray<oop*> check; 298 bool non_immed; 299 detect_reloc_oops(nm(), check, non_immed); 300 debug_stream.print_cr("check oops: %d", check.length()); 301 for (int i = 0; i < check.length(); i++) { 302 debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i))); 303 } 304 fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s", 305 oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.as_string()); 306 } 307 } 308 309 void ShenandoahNMethod::assert_no_oops(nmethod* nm, bool allow_dead) { 310 ShenandoahNMethodOopDetector detector; 311 nm->oops_do(&detector, allow_dead); 312 assert(detector.oops()->length() == 0, "Should not have oops"); 313 } 314 #endif 315 316 ShenandoahNMethodTable::ShenandoahNMethodTable() : 317 _heap(ShenandoahHeap::heap()), 318 _size(minSize), 319 _index(0), 320 _iteration_in_progress(false) { 321 _array = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, _size, mtGC); 322 } 323 324 ShenandoahNMethodTable::~ShenandoahNMethodTable() { 325 assert(_array != NULL, "Sanity"); 326 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _array); 327 } 328 329 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) { 330 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held"); 331 assert(_index >= 0 && _index <= _size, "Sanity"); 332 333 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 334 ShenandoahReentrantLocker data_locker(data != NULL ? data->lock() : NULL); 335 336 if (data != NULL) { 337 assert(contain(nm), "Must have been registered"); 338 assert(nm == data->nm(), "Must be same nmethod"); 339 data->update(); 340 } else { 341 data = ShenandoahNMethod::for_nmethod(nm); 342 if (data == NULL) { 343 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), 344 "Only possible when concurrent class unloading is off"); 345 return; 346 } 347 ShenandoahNMethod::attach_gc_data(nm, data); 348 ShenandoahLocker locker(&_lock); 349 log_register_nmethod(nm); 350 append(data); 351 } 352 // Disarm new nmethod 353 ShenandoahNMethod::disarm_nmethod(nm); 354 } 355 356 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) { 357 assert_locked_or_safepoint(CodeCache_lock); 358 359 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 360 if (data == NULL) { 361 assert(!ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), 362 "Only possible when concurrent class unloading is off"); 363 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/); 364 return; 365 } 366 367 if (Thread::current()->is_Code_cache_sweeper_thread()) { 368 wait_until_concurrent_iteration_done(); 369 } 370 log_unregister_nmethod(nm); 371 ShenandoahLocker locker(&_lock); 372 assert(contain(nm), "Must have been registered"); 373 374 ShenandoahReentrantLocker data_locker(data->lock()); 375 data->mark_unregistered(); 376 } 377 378 void ShenandoahNMethodTable::flush_nmethod(nmethod* nm) { 379 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held"); 380 assert(Thread::current()->is_Code_cache_sweeper_thread(), "Must from Sweep thread"); 381 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 382 assert(data != NULL || !ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), 383 "Only possible when concurrent class unloading is off"); 384 if (data == NULL) { 385 ShenandoahNMethod::assert_no_oops(nm, true /*allow_dead*/); 386 return; 387 } 388 389 // Can not alter the array when iteration is in progress 390 wait_until_concurrent_iteration_done(); 391 log_flush_nmethod(nm); 392 393 ShenandoahLocker locker(&_lock); 394 int idx = index_of(nm); 395 assert(idx >= 0 && idx < _index, "Invalid index"); 396 ShenandoahNMethod::attach_gc_data(nm, NULL); 397 remove(idx); 398 } 399 400 bool ShenandoahNMethodTable::contain(nmethod* nm) const { 401 return index_of(nm) != -1; 402 } 403 404 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const { 405 assert(index >= 0 && index < _index, "Out of bound"); 406 return _array[index]; 407 } 408 409 int ShenandoahNMethodTable::index_of(nmethod* nm) const { 410 for (int index = 0; index < length(); index ++) { 411 if (_array[index]->nm() == nm) { 412 return index; 413 } 414 } 415 return -1; 416 } 417 418 void ShenandoahNMethodTable::remove(int idx) { 419 shenandoah_assert_locked_or_safepoint(CodeCache_lock); 420 assert(!_iteration_in_progress, "Can not happen"); 421 assert(_index >= 0 && _index <= _size, "Sanity"); 422 423 assert(idx >= 0 && idx < _index, "Out of bound"); 424 ShenandoahNMethod* snm = _array[idx]; 425 426 _index --; 427 _array[idx] = _array[_index]; 428 429 delete snm; 430 } 431 432 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() { 433 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 434 while (iteration_in_progress()) { 435 CodeCache_lock->wait_without_safepoint_check(); 436 } 437 } 438 439 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) { 440 if (is_full()) { 441 int new_size = 2 * _size; 442 ShenandoahNMethod** old_table = _array; 443 444 // Rebuild table and replace current one 445 rebuild(new_size); 446 447 // An iteration is in progress over early snapshot, 448 // can not release the array until iteration is completed 449 if (!iteration_in_progress()) { 450 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, old_table); 451 } 452 } 453 454 _array[_index ++] = snm; 455 assert(_index >= 0 && _index <= _size, "Sanity"); 456 } 457 458 void ShenandoahNMethodTable::rebuild(int size) { 459 ShenandoahNMethod** arr = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC); 460 for (int index = 0; index < _index; index ++) { 461 arr[index] = _array[index]; 462 } 463 _array = arr; 464 _size = size; 465 } 466 467 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() { 468 assert(!iteration_in_progress(), "Already in progress"); 469 _iteration_in_progress = true; 470 471 return new ShenandoahNMethodTableSnapshot(this); 472 } 473 474 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) { 475 assert(iteration_in_progress(), "Why we here?"); 476 assert(snapshot != NULL, "No snapshot"); 477 _iteration_in_progress = false; 478 479 // Table has been rebuilt during iteration, free old table 480 if (snapshot->_array != _array) { 481 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, snapshot->_array); 482 } 483 delete snapshot; 484 } 485 486 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) { 487 LogTarget(Debug, gc, nmethod) log; 488 if (!log.is_enabled()) { 489 return; 490 } 491 492 ResourceMark rm; 493 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)", 494 nm->method()->method_holder()->external_name(), 495 nm->method()->name()->as_C_string(), 496 p2i(nm), 497 nm->compiler_name()); 498 } 499 500 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) { 501 LogTarget(Debug, gc, nmethod) log; 502 if (!log.is_enabled()) { 503 return; 504 } 505 506 ResourceMark rm; 507 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]", 508 nm->method()->method_holder()->external_name(), 509 nm->method()->name()->as_C_string(), 510 p2i(nm)); 511 } 512 513 void ShenandoahNMethodTable::log_flush_nmethod(nmethod* nm) { 514 LogTarget(Debug, gc, nmethod) log; 515 if (!log.is_enabled()) { 516 return; 517 } 518 519 ResourceMark rm; 520 log.print("Flush NMethod: (" PTR_FORMAT ")", p2i(nm)); 521 } 522 523 #ifdef ASSERT 524 void ShenandoahNMethodTable::assert_nmethods_alive_and_correct() { 525 assert_locked_or_safepoint(CodeCache_lock); 526 527 for (int index = 0; index < length(); index ++) { 528 ShenandoahNMethod* m = _array[index]; 529 // Concurrent unloading may have dead nmethods to be cleaned by sweeper 530 if (m->is_unregistered()) continue; 531 m->assert_alive_and_correct(); 532 } 533 } 534 #endif 535 536 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) : 537 _heap(ShenandoahHeap::heap()), _table(table), _array(table->_array), _length(table->_index), _claimed(0) { 538 } 539 540 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) { 541 size_t stride = 256; // educated guess 542 543 ShenandoahNMethod** list = _array; 544 size_t max = (size_t)_length; 545 while (_claimed < max) { 546 size_t cur = Atomic::fetch_and_add(&_claimed, stride); 547 size_t start = cur; 548 size_t end = MIN2(cur + stride, max); 549 if (start >= max) break; 550 551 for (size_t idx = start; idx < end; idx++) { 552 ShenandoahNMethod* data = list[idx]; 553 assert(data != NULL, "Should not be NULL"); 554 if (!data->is_unregistered()) { 555 cl->do_nmethod(data->nm()); 556 } 557 } 558 } 559 } 560 561 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) : 562 _table(table), _table_snapshot(NULL) { 563 } 564 565 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() { 566 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 567 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), 568 "Only for concurrent class unloading"); 569 _table_snapshot = _table->snapshot_for_iteration(); 570 } 571 572 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) { 573 assert(_table_snapshot != NULL, "Must first call nmethod_do_begin()"); 574 _table_snapshot->concurrent_nmethods_do(cl); 575 } 576 577 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() { 578 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 579 assert(ShenandoahConcurrentRoots::can_do_concurrent_class_unloading(), 580 "Only for concurrent class unloading"); 581 _table->finish_iteration(_table_snapshot); 582 CodeCache_lock->notify_all(); 583 }