1 /* 2 * Copyright (c) 2019, 2022, 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/shenandoahHeap.inline.hpp" 29 #include "gc/shenandoah/shenandoahNMethod.inline.hpp" 30 #include "gc/shenandoah/shenandoahOopClosures.inline.hpp" 31 #include "memory/resourceArea.hpp" 32 #include "runtime/continuation.hpp" 33 34 ShenandoahNMethod::ShenandoahNMethod(nmethod* nm, GrowableArray<oop*>& oops, bool non_immediate_oops) : 35 _nm(nm), _oops(nullptr), _oops_count(0), _unregistered(false) { 36 37 if (!oops.is_empty()) { 38 _oops_count = oops.length(); 39 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC); 40 for (int c = 0; c < _oops_count; c++) { 41 _oops[c] = oops.at(c); 42 } 43 } 44 _has_non_immed_oops = non_immediate_oops; 45 46 assert_same_oops(); 47 } 48 49 ShenandoahNMethod::~ShenandoahNMethod() { 50 if (_oops != nullptr) { 51 FREE_C_HEAP_ARRAY(oop*, _oops); 52 } 53 } 54 55 class ShenandoahHasCSetOopClosure : public OopClosure { 56 private: 57 ShenandoahHeap* const _heap; 58 bool _has_cset_oops; 59 60 public: 61 ShenandoahHasCSetOopClosure(ShenandoahHeap *heap) : 62 _heap(heap), 63 _has_cset_oops(false) { 64 } 65 66 bool has_cset_oops() const { 67 return _has_cset_oops; 68 } 69 70 void do_oop(oop* p) { 71 oop value = RawAccess<>::oop_load(p); 72 if (!_has_cset_oops && _heap->in_collection_set(value)) { 73 _has_cset_oops = true; 74 } 75 } 76 77 void do_oop(narrowOop* p) { 78 ShouldNotReachHere(); 79 } 80 }; 81 82 bool ShenandoahNMethod::has_cset_oops(ShenandoahHeap *heap) { 83 ShenandoahHasCSetOopClosure cl(heap); 84 oops_do(&cl); 85 return cl.has_cset_oops(); 86 } 87 88 void ShenandoahNMethod::update() { 89 ResourceMark rm; 90 bool non_immediate_oops = false; 91 GrowableArray<oop*> oops; 92 93 detect_reloc_oops(nm(), oops, non_immediate_oops); 94 if (oops.length() != _oops_count) { 95 if (_oops != nullptr) { 96 FREE_C_HEAP_ARRAY(oop*, _oops); 97 _oops = nullptr; 98 } 99 100 _oops_count = oops.length(); 101 if (_oops_count > 0) { 102 _oops = NEW_C_HEAP_ARRAY(oop*, _oops_count, mtGC); 103 } 104 } 105 106 for (int index = 0; index < _oops_count; index ++) { 107 _oops[index] = oops.at(index); 108 } 109 _has_non_immed_oops = non_immediate_oops; 110 111 assert_same_oops(); 112 } 113 114 void ShenandoahNMethod::detect_reloc_oops(nmethod* nm, GrowableArray<oop*>& oops, bool& has_non_immed_oops) { 115 has_non_immed_oops = false; 116 // Find all oops relocations 117 RelocIterator iter(nm); 118 while (iter.next()) { 119 if (iter.type() != relocInfo::oop_type) { 120 // Not an oop 121 continue; 122 } 123 124 oop_Relocation* r = iter.oop_reloc(); 125 if (!r->oop_is_immediate()) { 126 // Non-immediate oop found 127 has_non_immed_oops = true; 128 continue; 129 } 130 131 oop value = r->oop_value(); 132 if (value != nullptr) { 133 oop* addr = r->oop_addr(); 134 shenandoah_assert_correct(addr, value); 135 shenandoah_assert_not_in_cset_except(addr, value, ShenandoahHeap::heap()->cancelled_gc()); 136 shenandoah_assert_not_forwarded(addr, value); 137 // Non-null immediate oop found. null oops can safely be 138 // ignored since the method will be re-registered if they 139 // are later patched to be non-null. 140 oops.push(addr); 141 } 142 } 143 } 144 145 ShenandoahNMethod* ShenandoahNMethod::for_nmethod(nmethod* nm) { 146 ResourceMark rm; 147 bool non_immediate_oops = false; 148 GrowableArray<oop*> oops; 149 150 detect_reloc_oops(nm, oops, non_immediate_oops); 151 return new ShenandoahNMethod(nm, oops, non_immediate_oops); 152 } 153 154 void ShenandoahNMethod::heal_nmethod(nmethod* nm) { 155 ShenandoahNMethod* data = gc_data(nm); 156 assert(data != nullptr, "Sanity"); 157 assert(data->lock()->owned_by_self(), "Must hold the lock"); 158 159 ShenandoahHeap* const heap = ShenandoahHeap::heap(); 160 if (heap->is_concurrent_mark_in_progress()) { 161 ShenandoahKeepAliveClosure cl; 162 data->oops_do(&cl); 163 } else if (heap->is_concurrent_weak_root_in_progress() || 164 heap->is_concurrent_strong_root_in_progress() ) { 165 ShenandoahEvacOOMScope evac_scope; 166 heal_nmethod_metadata(data); 167 } else { 168 // There is possibility that GC is cancelled when it arrives final mark. 169 // In this case, concurrent root phase is skipped and degenerated GC should be 170 // followed, where nmethods are disarmed. 171 } 172 } 173 174 #ifdef ASSERT 175 void ShenandoahNMethod::assert_correct() { 176 ShenandoahHeap* heap = ShenandoahHeap::heap(); 177 for (int c = 0; c < _oops_count; c++) { 178 oop *loc = _oops[c]; 179 assert(_nm->code_contains((address) loc) || _nm->oops_contains(loc), "nmethod should contain the oop*"); 180 oop o = RawAccess<>::oop_load(loc); 181 shenandoah_assert_correct_except(loc, o, o == nullptr || heap->is_full_gc_move_in_progress()); 182 } 183 184 oop* const begin = _nm->oops_begin(); 185 oop* const end = _nm->oops_end(); 186 for (oop* p = begin; p < end; p++) { 187 if (*p != Universe::non_oop_word()) { 188 oop o = RawAccess<>::oop_load(p); 189 shenandoah_assert_correct_except(p, o, o == nullptr || heap->is_full_gc_move_in_progress()); 190 } 191 } 192 } 193 194 class ShenandoahNMethodOopDetector : public OopClosure { 195 private: 196 ResourceMark rm; // For growable array allocation below. 197 GrowableArray<oop*> _oops; 198 199 public: 200 ShenandoahNMethodOopDetector() : _oops(10) {}; 201 202 void do_oop(oop* o) { 203 _oops.append(o); 204 } 205 void do_oop(narrowOop* o) { 206 fatal("NMethods should not have compressed oops embedded."); 207 } 208 209 GrowableArray<oop*>* oops() { 210 return &_oops; 211 } 212 213 bool has_oops() { 214 return !_oops.is_empty(); 215 } 216 }; 217 218 void ShenandoahNMethod::assert_same_oops(bool allow_dead) { 219 ShenandoahNMethodOopDetector detector; 220 nm()->oops_do(&detector, allow_dead); 221 222 GrowableArray<oop*>* oops = detector.oops(); 223 224 int count = _oops_count; 225 for (int index = 0; index < _oops_count; index ++) { 226 assert(oops->contains(_oops[index]), "Must contain this oop"); 227 } 228 229 for (oop* p = nm()->oops_begin(); p < nm()->oops_end(); p ++) { 230 if (*p == Universe::non_oop_word()) continue; 231 count++; 232 assert(oops->contains(p), "Must contain this oop"); 233 } 234 235 if (oops->length() < count) { 236 stringStream debug_stream; 237 debug_stream.print_cr("detected locs: %d", oops->length()); 238 for (int i = 0; i < oops->length(); i++) { 239 debug_stream.print_cr("-> " PTR_FORMAT, p2i(oops->at(i))); 240 } 241 debug_stream.print_cr("recorded oops: %d", _oops_count); 242 for (int i = 0; i < _oops_count; i++) { 243 debug_stream.print_cr("-> " PTR_FORMAT, p2i(_oops[i])); 244 } 245 GrowableArray<oop*> check; 246 bool non_immed; 247 detect_reloc_oops(nm(), check, non_immed); 248 debug_stream.print_cr("check oops: %d", check.length()); 249 for (int i = 0; i < check.length(); i++) { 250 debug_stream.print_cr("-> " PTR_FORMAT, p2i(check.at(i))); 251 } 252 fatal("Must match #detected: %d, #recorded: %d, #total: %d, begin: " PTR_FORMAT ", end: " PTR_FORMAT "\n%s", 253 oops->length(), _oops_count, count, p2i(nm()->oops_begin()), p2i(nm()->oops_end()), debug_stream.freeze()); 254 } 255 } 256 #endif 257 258 ShenandoahNMethodTable::ShenandoahNMethodTable() : 259 _heap(ShenandoahHeap::heap()), 260 _index(0), 261 _itr_cnt(0) { 262 _list = new ShenandoahNMethodList(minSize); 263 } 264 265 ShenandoahNMethodTable::~ShenandoahNMethodTable() { 266 assert(_list != nullptr, "Sanity"); 267 _list->release(); 268 } 269 270 void ShenandoahNMethodTable::register_nmethod(nmethod* nm) { 271 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held"); 272 assert(_index >= 0 && _index <= _list->size(), "Sanity"); 273 274 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 275 276 if (data != nullptr) { 277 assert(contain(nm), "Must have been registered"); 278 assert(nm == data->nm(), "Must be same nmethod"); 279 // Prevent updating a nmethod while concurrent iteration is in progress. 280 wait_until_concurrent_iteration_done(); 281 ShenandoahReentrantLocker data_locker(data->lock()); 282 data->update(); 283 } else { 284 // For a new nmethod, we can safely append it to the list, because 285 // concurrent iteration will not touch it. 286 data = ShenandoahNMethod::for_nmethod(nm); 287 assert(data != nullptr, "Sanity"); 288 ShenandoahNMethod::attach_gc_data(nm, data); 289 ShenandoahLocker locker(&_lock); 290 log_register_nmethod(nm); 291 append(data); 292 } 293 // Disarm new nmethod 294 ShenandoahNMethod::disarm_nmethod(nm); 295 } 296 297 void ShenandoahNMethodTable::unregister_nmethod(nmethod* nm) { 298 assert_locked_or_safepoint(CodeCache_lock); 299 300 ShenandoahNMethod* data = ShenandoahNMethod::gc_data(nm); 301 assert(data != nullptr, "Sanity"); 302 log_unregister_nmethod(nm); 303 ShenandoahLocker locker(&_lock); 304 assert(contain(nm), "Must have been registered"); 305 306 int idx = index_of(nm); 307 assert(idx >= 0 && idx < _index, "Invalid index"); 308 ShenandoahNMethod::attach_gc_data(nm, nullptr); 309 remove(idx); 310 } 311 312 bool ShenandoahNMethodTable::contain(nmethod* nm) const { 313 return index_of(nm) != -1; 314 } 315 316 ShenandoahNMethod* ShenandoahNMethodTable::at(int index) const { 317 assert(index >= 0 && index < _index, "Out of bound"); 318 return _list->at(index); 319 } 320 321 int ShenandoahNMethodTable::index_of(nmethod* nm) const { 322 for (int index = 0; index < length(); index ++) { 323 if (at(index)->nm() == nm) { 324 return index; 325 } 326 } 327 return -1; 328 } 329 330 void ShenandoahNMethodTable::remove(int idx) { 331 shenandoah_assert_locked_or_safepoint(CodeCache_lock); 332 assert(_index >= 0 && _index <= _list->size(), "Sanity"); 333 334 assert(idx >= 0 && idx < _index, "Out of bound"); 335 ShenandoahNMethod* snm = _list->at(idx); 336 ShenandoahNMethod* tmp = _list->at(_index - 1); 337 _list->set(idx, tmp); 338 _index --; 339 340 delete snm; 341 } 342 343 void ShenandoahNMethodTable::wait_until_concurrent_iteration_done() { 344 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 345 while (iteration_in_progress()) { 346 CodeCache_lock->wait_without_safepoint_check(); 347 } 348 } 349 350 void ShenandoahNMethodTable::append(ShenandoahNMethod* snm) { 351 if (is_full()) { 352 int new_size = 2 * _list->size(); 353 // Rebuild table and replace current one 354 rebuild(new_size); 355 } 356 357 _list->set(_index++, snm); 358 assert(_index >= 0 && _index <= _list->size(), "Sanity"); 359 } 360 361 void ShenandoahNMethodTable::rebuild(int size) { 362 ShenandoahNMethodList* new_list = new ShenandoahNMethodList(size); 363 new_list->transfer(_list, _index); 364 365 // Release old list 366 _list->release(); 367 _list = new_list; 368 } 369 370 ShenandoahNMethodTableSnapshot* ShenandoahNMethodTable::snapshot_for_iteration() { 371 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held"); 372 _itr_cnt++; 373 return new ShenandoahNMethodTableSnapshot(this); 374 } 375 376 void ShenandoahNMethodTable::finish_iteration(ShenandoahNMethodTableSnapshot* snapshot) { 377 assert(CodeCache_lock->owned_by_self(), "Must have CodeCache_lock held"); 378 assert(iteration_in_progress(), "Why we here?"); 379 assert(snapshot != nullptr, "No snapshot"); 380 _itr_cnt--; 381 382 delete snapshot; 383 } 384 385 void ShenandoahNMethodTable::log_register_nmethod(nmethod* nm) { 386 LogTarget(Debug, gc, nmethod) log; 387 if (!log.is_enabled()) { 388 return; 389 } 390 391 ResourceMark rm; 392 log.print("Register NMethod: %s.%s [" PTR_FORMAT "] (%s)", 393 nm->method()->method_holder()->external_name(), 394 nm->method()->name()->as_C_string(), 395 p2i(nm), 396 nm->compiler_name()); 397 } 398 399 void ShenandoahNMethodTable::log_unregister_nmethod(nmethod* nm) { 400 LogTarget(Debug, gc, nmethod) log; 401 if (!log.is_enabled()) { 402 return; 403 } 404 405 ResourceMark rm; 406 log.print("Unregister NMethod: %s.%s [" PTR_FORMAT "]", 407 nm->method()->method_holder()->external_name(), 408 nm->method()->name()->as_C_string(), 409 p2i(nm)); 410 } 411 412 #ifdef ASSERT 413 void ShenandoahNMethodTable::assert_nmethods_correct() { 414 assert_locked_or_safepoint(CodeCache_lock); 415 416 for (int index = 0; index < length(); index ++) { 417 ShenandoahNMethod* m = _list->at(index); 418 // Concurrent unloading may have dead nmethods to be cleaned by sweeper 419 if (m->is_unregistered()) continue; 420 m->assert_correct(); 421 } 422 } 423 #endif 424 425 426 ShenandoahNMethodList::ShenandoahNMethodList(int size) : 427 _size(size), _ref_count(1) { 428 _list = NEW_C_HEAP_ARRAY(ShenandoahNMethod*, size, mtGC); 429 } 430 431 ShenandoahNMethodList::~ShenandoahNMethodList() { 432 assert(_list != nullptr, "Sanity"); 433 assert(_ref_count == 0, "Must be"); 434 FREE_C_HEAP_ARRAY(ShenandoahNMethod*, _list); 435 } 436 437 void ShenandoahNMethodList::transfer(ShenandoahNMethodList* const list, int limit) { 438 assert(limit <= size(), "Sanity"); 439 ShenandoahNMethod** old_list = list->list(); 440 for (int index = 0; index < limit; index++) { 441 _list[index] = old_list[index]; 442 } 443 } 444 445 ShenandoahNMethodList* ShenandoahNMethodList::acquire() { 446 assert_locked_or_safepoint(CodeCache_lock); 447 _ref_count++; 448 return this; 449 } 450 451 void ShenandoahNMethodList::release() { 452 assert_locked_or_safepoint(CodeCache_lock); 453 _ref_count--; 454 if (_ref_count == 0) { 455 delete this; 456 } 457 } 458 459 ShenandoahNMethodTableSnapshot::ShenandoahNMethodTableSnapshot(ShenandoahNMethodTable* table) : 460 _heap(ShenandoahHeap::heap()), _list(table->_list->acquire()), _limit(table->_index), _claimed(0) { 461 } 462 463 ShenandoahNMethodTableSnapshot::~ShenandoahNMethodTableSnapshot() { 464 _list->release(); 465 } 466 467 void ShenandoahNMethodTableSnapshot::parallel_blobs_do(CodeBlobClosure *f) { 468 size_t stride = 256; // educated guess 469 470 ShenandoahNMethod** const list = _list->list(); 471 472 size_t max = (size_t)_limit; 473 while (_claimed < max) { 474 size_t cur = Atomic::fetch_then_add(&_claimed, stride, memory_order_relaxed); 475 size_t start = cur; 476 size_t end = MIN2(cur + stride, max); 477 if (start >= max) break; 478 479 for (size_t idx = start; idx < end; idx++) { 480 ShenandoahNMethod* nmr = list[idx]; 481 assert(nmr != nullptr, "Sanity"); 482 if (nmr->is_unregistered()) { 483 continue; 484 } 485 486 nmr->assert_correct(); 487 f->do_code_blob(nmr->nm()); 488 } 489 } 490 } 491 492 void ShenandoahNMethodTableSnapshot::concurrent_nmethods_do(NMethodClosure* cl) { 493 size_t stride = 256; // educated guess 494 495 ShenandoahNMethod** list = _list->list(); 496 size_t max = (size_t)_limit; 497 while (_claimed < max) { 498 size_t cur = Atomic::fetch_then_add(&_claimed, stride, memory_order_relaxed); 499 size_t start = cur; 500 size_t end = MIN2(cur + stride, max); 501 if (start >= max) break; 502 503 for (size_t idx = start; idx < end; idx++) { 504 ShenandoahNMethod* data = list[idx]; 505 assert(data != nullptr, "Should not be null"); 506 if (!data->is_unregistered()) { 507 cl->do_nmethod(data->nm()); 508 } 509 } 510 } 511 } 512 513 ShenandoahConcurrentNMethodIterator::ShenandoahConcurrentNMethodIterator(ShenandoahNMethodTable* table) : 514 _table(table), _table_snapshot(nullptr) { 515 } 516 517 void ShenandoahConcurrentNMethodIterator::nmethods_do_begin() { 518 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 519 _table_snapshot = _table->snapshot_for_iteration(); 520 } 521 522 void ShenandoahConcurrentNMethodIterator::nmethods_do(NMethodClosure* cl) { 523 assert(_table_snapshot != nullptr, "Must first call nmethod_do_begin()"); 524 _table_snapshot->concurrent_nmethods_do(cl); 525 } 526 527 void ShenandoahConcurrentNMethodIterator::nmethods_do_end() { 528 assert(CodeCache_lock->owned_by_self(), "Lock must be held"); 529 _table->finish_iteration(_table_snapshot); 530 CodeCache_lock->notify_all(); 531 }