1 /* 2 * Copyright (c) 2012, 2013, 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 25 // A ClassLoaderData identifies the full set of class types that a class 26 // loader's name resolution strategy produces for a given configuration of the 27 // class loader. 28 // Class types in the ClassLoaderData may be defined by from class file binaries 29 // provided by the class loader, or from other class loader it interacts with 30 // according to its name resolution strategy. 31 // 32 // Class loaders that implement a deterministic name resolution strategy 33 // (including with respect to their delegation behavior), such as the boot, the 34 // extension, and the system loaders of the JDK's built-in class loader 35 // hierarchy, always produce the same linkset for a given configuration. 36 // 37 // ClassLoaderData carries information related to a linkset (e.g., 38 // metaspace holding its klass definitions). 39 // The System Dictionary and related data structures (e.g., placeholder table, 40 // loader constraints table) as well as the runtime representation of classes 41 // only reference ClassLoaderData. 42 // 43 // Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that 44 // that represent the loader's "linking domain" in the JVM. 45 // 46 // The bootstrap loader (represented by NULL) also has a ClassLoaderData, 47 // the singleton class the_null_class_loader_data(). 48 49 #include "precompiled.hpp" 50 #include "classfile/classLoaderData.hpp" 51 #include "classfile/classLoaderData.inline.hpp" 52 #include "classfile/javaClasses.hpp" 53 #include "classfile/metadataOnStackMark.hpp" 54 #include "classfile/systemDictionary.hpp" 55 #include "code/codeCache.hpp" 56 #include "memory/metadataFactory.hpp" 57 #include "memory/metaspaceShared.hpp" 58 #include "memory/oopFactory.hpp" 59 #include "runtime/jniHandles.hpp" 60 #include "runtime/mutex.hpp" 61 #include "runtime/safepoint.hpp" 62 #include "runtime/synchronizer.hpp" 63 #include "utilities/growableArray.hpp" 64 #include "utilities/ostream.hpp" 65 66 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL; 67 68 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_anonymous) : 69 _class_loader(h_class_loader()), 70 _is_anonymous(is_anonymous), _keep_alive(is_anonymous), // initially 71 _metaspace(NULL), _unloading(false), _klasses(NULL), 72 _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL), 73 _next(NULL), _dependencies(NULL), 74 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) { 75 // empty 76 } 77 78 void ClassLoaderData::init_dependencies(TRAPS) { 79 // Create empty dependencies array to add to. CMS requires this to be 80 // an oop so that it can track additions via card marks. We think. 81 _dependencies = (oop)oopFactory::new_objectArray(2, CHECK); 82 } 83 84 bool ClassLoaderData::claim() { 85 if (_claimed == 1) { 86 return false; 87 } 88 89 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0; 90 } 91 92 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 93 if (must_claim && !claim()) { 94 return; 95 } 96 97 f->do_oop(&_class_loader); 98 f->do_oop(&_dependencies); 99 _handles->oops_do(f); 100 if (klass_closure != NULL) { 101 classes_do(klass_closure); 102 } 103 } 104 105 void ClassLoaderData::classes_do(KlassClosure* klass_closure) { 106 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 107 klass_closure->do_klass(k); 108 assert(k != k->next_link(), "no loops!"); 109 } 110 } 111 112 void ClassLoaderData::classes_do(void f(InstanceKlass*)) { 113 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 114 if (k->oop_is_instance()) { 115 f(InstanceKlass::cast(k)); 116 } 117 assert(k != k->next_link(), "no loops!"); 118 } 119 } 120 121 void ClassLoaderData::record_dependency(Klass* k, TRAPS) { 122 ClassLoaderData * const from_cld = this; 123 ClassLoaderData * const to_cld = k->class_loader_data(); 124 125 // Dependency to the null class loader data doesn't need to be recorded 126 // because the null class loader data never goes away. 127 if (to_cld->is_the_null_class_loader_data()) { 128 return; 129 } 130 131 oop to; 132 if (to_cld->is_anonymous()) { 133 // Anonymous class dependencies are through the mirror. 134 to = k->java_mirror(); 135 } else { 136 to = to_cld->class_loader(); 137 138 // If from_cld is anonymous, even if it's class_loader is a parent of 'to' 139 // we still have to add it. The class_loader won't keep from_cld alive. 140 if (!from_cld->is_anonymous()) { 141 // Check that this dependency isn't from the same or parent class_loader 142 oop from = from_cld->class_loader(); 143 144 oop curr = from; 145 while (curr != NULL) { 146 if (curr == to) { 147 return; // this class loader is in the parent list, no need to add it. 148 } 149 curr = java_lang_ClassLoader::parent(curr); 150 } 151 } 152 } 153 154 // It's a dependency we won't find through GC, add it. This is relatively rare 155 // Must handle over GC point. 156 Handle dependency(THREAD, to); 157 from_cld->add_dependency(dependency, CHECK); 158 } 159 160 161 void ClassLoaderData::add_dependency(Handle dependency, TRAPS) { 162 // Check first if this dependency is already in the list. 163 // Save a pointer to the last to add to under the lock. 164 objArrayOop ok = (objArrayOop)_dependencies; 165 objArrayOop last = NULL; 166 while (ok != NULL) { 167 last = ok; 168 if (ok->obj_at(0) == dependency()) { 169 // Don't need to add it 170 return; 171 } 172 ok = (objArrayOop)ok->obj_at(1); 173 } 174 175 // Must handle over GC points 176 assert (last != NULL, "dependencies should be initialized"); 177 objArrayHandle last_handle(THREAD, last); 178 179 // Create a new dependency node with fields for (class_loader or mirror, next) 180 objArrayOop deps = oopFactory::new_objectArray(2, CHECK); 181 deps->obj_at_put(0, dependency()); 182 183 // Must handle over GC points 184 objArrayHandle new_dependency(THREAD, deps); 185 186 // Add the dependency under lock 187 locked_add_dependency(last_handle, new_dependency); 188 } 189 190 void ClassLoaderData::locked_add_dependency(objArrayHandle last_handle, 191 objArrayHandle new_dependency) { 192 193 // Have to lock and put the new dependency on the end of the dependency 194 // array so the card mark for CMS sees that this dependency is new. 195 // Can probably do this lock free with some effort. 196 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 197 198 oop loader_or_mirror = new_dependency->obj_at(0); 199 200 // Since the dependencies are only added, add to the end. 201 objArrayOop end = last_handle(); 202 objArrayOop last = NULL; 203 while (end != NULL) { 204 last = end; 205 // check again if another thread added it to the end. 206 if (end->obj_at(0) == loader_or_mirror) { 207 // Don't need to add it 208 return; 209 } 210 end = (objArrayOop)end->obj_at(1); 211 } 212 assert (last != NULL, "dependencies should be initialized"); 213 // fill in the first element with the oop in new_dependency. 214 if (last->obj_at(0) == NULL) { 215 last->obj_at_put(0, new_dependency->obj_at(0)); 216 } else { 217 last->obj_at_put(1, new_dependency()); 218 } 219 } 220 221 void ClassLoaderDataGraph::clear_claimed_marks() { 222 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 223 cld->clear_claimed(); 224 } 225 } 226 227 void ClassLoaderData::add_class(Klass* k) { 228 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 229 Klass* old_value = _klasses; 230 k->set_next_link(old_value); 231 // link the new item into the list 232 _klasses = k; 233 234 if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) { 235 ResourceMark rm; 236 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: " 237 PTR_FORMAT " loader: " PTR_FORMAT " %s", 238 k, 239 k->external_name(), 240 k->class_loader_data(), 241 k->class_loader(), 242 loader_name()); 243 } 244 } 245 246 // This is called by InstanceKlass::deallocate_contents() to remove the 247 // scratch_class for redefine classes. We need a lock because there it may not 248 // be called at a safepoint if there's an error. 249 void ClassLoaderData::remove_class(Klass* scratch_class) { 250 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 251 Klass* prev = NULL; 252 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 253 if (k == scratch_class) { 254 if (prev == NULL) { 255 _klasses = k->next_link(); 256 } else { 257 Klass* next = k->next_link(); 258 prev->set_next_link(next); 259 } 260 return; 261 } 262 prev = k; 263 assert(k != k->next_link(), "no loops!"); 264 } 265 ShouldNotReachHere(); // should have found this class!! 266 } 267 268 void ClassLoaderData::unload() { 269 _unloading = true; 270 271 if (TraceClassLoaderData) { 272 ResourceMark rm; 273 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this); 274 tty->print(" for instance "PTR_FORMAT" of %s", class_loader(), 275 loader_name()); 276 if (is_anonymous()) { 277 tty->print(" for anonymous class "PTR_FORMAT " ", _klasses); 278 } 279 tty->print_cr("]"); 280 } 281 } 282 283 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const { 284 bool alive = 285 is_anonymous() ? 286 is_alive_closure->do_object_b(_klasses->java_mirror()) : 287 class_loader() == NULL || is_alive_closure->do_object_b(class_loader()); 288 assert(!alive || claimed(), "must be claimed"); 289 return alive; 290 } 291 292 293 ClassLoaderData::~ClassLoaderData() { 294 Metaspace *m = _metaspace; 295 if (m != NULL) { 296 _metaspace = NULL; 297 // release the metaspace 298 delete m; 299 // release the handles 300 if (_handles != NULL) { 301 JNIHandleBlock::release_block(_handles); 302 _handles = NULL; 303 } 304 } 305 306 // Clear all the JNI handles for methods 307 // These aren't deallocated and are going to look like a leak, but that's 308 // needed because we can't really get rid of jmethodIDs because we don't 309 // know when native code is going to stop using them. The spec says that 310 // they're "invalid" but existing programs likely rely on their being 311 // NULL after class unloading. 312 if (_jmethod_ids != NULL) { 313 Method::clear_jmethod_ids(this); 314 } 315 // Delete lock 316 delete _metaspace_lock; 317 318 // Delete free list 319 if (_deallocate_list != NULL) { 320 delete _deallocate_list; 321 } 322 } 323 324 Metaspace* ClassLoaderData::metaspace_non_null() { 325 assert(!DumpSharedSpaces, "wrong metaspace!"); 326 // If the metaspace has not been allocated, create a new one. Might want 327 // to create smaller arena for Reflection class loaders also. 328 // The reason for the delayed allocation is because some class loaders are 329 // simply for delegating with no metadata of their own. 330 if (_metaspace == NULL) { 331 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 332 // Check again if metaspace has been allocated while we were getting this lock. 333 if (_metaspace != NULL) { 334 return _metaspace; 335 } 336 if (this == the_null_class_loader_data()) { 337 assert (class_loader() == NULL, "Must be"); 338 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::BootMetaspaceType)); 339 } else if (is_anonymous()) { 340 if (TraceClassLoaderData && Verbose && class_loader() != NULL) { 341 tty->print_cr("is_anonymous: %s", class_loader()->klass()->internal_name()); 342 } 343 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::AnonymousMetaspaceType)); 344 } else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) { 345 if (TraceClassLoaderData && Verbose && class_loader() != NULL) { 346 tty->print_cr("is_reflection: %s", class_loader()->klass()->internal_name()); 347 } 348 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::ReflectionMetaspaceType)); 349 } else { 350 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::StandardMetaspaceType)); 351 } 352 } 353 return _metaspace; 354 } 355 356 JNIHandleBlock* ClassLoaderData::handles() const { return _handles; } 357 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; } 358 359 jobject ClassLoaderData::add_handle(Handle h) { 360 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 361 if (handles() == NULL) { 362 set_handles(JNIHandleBlock::allocate_block()); 363 } 364 return handles()->allocate_handle(h()); 365 } 366 367 // Add this metadata pointer to be freed when it's safe. This is only during 368 // class unloading because Handles might point to this metadata field. 369 void ClassLoaderData::add_to_deallocate_list(Metadata* m) { 370 // Metadata in shared region isn't deleted. 371 if (!m->is_shared()) { 372 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 373 if (_deallocate_list == NULL) { 374 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true); 375 } 376 _deallocate_list->append_if_missing(m); 377 } 378 } 379 380 // Deallocate free metadata on the free list. How useful the PermGen was! 381 void ClassLoaderData::free_deallocate_list() { 382 // Don't need lock, at safepoint 383 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint"); 384 if (_deallocate_list == NULL) { 385 return; 386 } 387 // Go backwards because this removes entries that are freed. 388 for (int i = _deallocate_list->length() - 1; i >= 0; i--) { 389 Metadata* m = _deallocate_list->at(i); 390 if (!m->on_stack()) { 391 _deallocate_list->remove_at(i); 392 // There are only three types of metadata that we deallocate directly. 393 // Cast them so they can be used by the template function. 394 if (m->is_method()) { 395 MetadataFactory::free_metadata(this, (Method*)m); 396 } else if (m->is_constantPool()) { 397 MetadataFactory::free_metadata(this, (ConstantPool*)m); 398 } else if (m->is_klass()) { 399 MetadataFactory::free_metadata(this, (InstanceKlass*)m); 400 } else { 401 ShouldNotReachHere(); 402 } 403 } 404 } 405 } 406 407 // These anonymous class loaders are to contain classes used for JSR292 408 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) { 409 // Add a new class loader data to the graph. 410 return ClassLoaderDataGraph::add(NULL, loader, CHECK_NULL); 411 } 412 413 const char* ClassLoaderData::loader_name() { 414 // Handles null class loader 415 return SystemDictionary::loader_name(class_loader()); 416 } 417 418 #ifndef PRODUCT 419 // Define to dump klasses 420 #undef CLD_DUMP_KLASSES 421 422 void ClassLoaderData::dump(outputStream * const out) { 423 ResourceMark rm; 424 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {", 425 this, class_loader(), 426 class_loader() != NULL ? class_loader()->klass() : NULL, loader_name()); 427 if (claimed()) out->print(" claimed "); 428 if (is_unloading()) out->print(" unloading "); 429 out->print(" handles " INTPTR_FORMAT, handles()); 430 out->cr(); 431 if (metaspace_or_null() != NULL) { 432 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null()); 433 metaspace_or_null()->dump(out); 434 } else { 435 out->print_cr("metaspace: NULL"); 436 } 437 438 #ifdef CLD_DUMP_KLASSES 439 if (Verbose) { 440 ResourceMark rm; 441 Klass* k = _klasses; 442 while (k != NULL) { 443 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(), 444 k->has_modified_oops(), k->has_accumulated_modified_oops()); 445 assert(k != k->next_link(), "no loops!"); 446 k = k->next_link(); 447 } 448 } 449 #endif // CLD_DUMP_KLASSES 450 #undef CLD_DUMP_KLASSES 451 if (_jmethod_ids != NULL) { 452 Method::print_jmethod_ids(this, out); 453 } 454 out->print_cr("}"); 455 } 456 #endif // PRODUCT 457 458 void ClassLoaderData::verify() { 459 oop cl = class_loader(); 460 461 guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same"); 462 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be"); 463 464 // Verify the integrity of the allocated space. 465 if (metaspace_or_null() != NULL) { 466 metaspace_or_null()->verify(); 467 } 468 469 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { 470 guarantee(k->class_loader_data() == this, "Must be the same"); 471 k->verify(); 472 assert(k != k->next_link(), "no loops!"); 473 } 474 } 475 476 477 // GC root of class loader data created. 478 ClassLoaderData* ClassLoaderDataGraph::_head = NULL; 479 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL; 480 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL; 481 482 483 // Add a new class loader data node to the list. Assign the newly created 484 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field 485 ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader, TRAPS) { 486 // Not assigned a class loader data yet. 487 // Create one. 488 ClassLoaderData* *list_head = &_head; 489 ClassLoaderData* next = _head; 490 491 bool is_anonymous = (cld_addr == NULL); 492 ClassLoaderData* cld = new ClassLoaderData(loader, is_anonymous); 493 494 if (cld_addr != NULL) { 495 // First, Atomically set it 496 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL); 497 if (old != NULL) { 498 delete cld; 499 // Returns the data. 500 return old; 501 } 502 } 503 504 // We won the race, and therefore the task of adding the data to the list of 505 // class loader data 506 do { 507 cld->set_next(next); 508 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next); 509 if (exchanged == next) { 510 if (TraceClassLoaderData) { 511 ResourceMark rm; 512 tty->print("[ClassLoaderData: "); 513 tty->print("create class loader data "PTR_FORMAT, cld); 514 tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(), 515 cld->loader_name()); 516 tty->print_cr("]"); 517 } 518 // Create dependencies after the CLD is added to the list. Otherwise, 519 // the GC GC will not find the CLD and the _class_loader field will 520 // not be updated. 521 cld->init_dependencies(CHECK_NULL); 522 return cld; 523 } 524 next = exchanged; 525 } while (true); 526 527 } 528 529 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 530 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 531 cld->oops_do(f, klass_closure, must_claim); 532 } 533 } 534 535 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 536 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 537 if (cld->keep_alive()) { 538 cld->oops_do(f, klass_closure, must_claim); 539 } 540 } 541 } 542 543 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) { 544 if (ClassUnloading) { 545 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim); 546 // keep any special CLDs alive. 547 ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim); 548 } else { 549 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim); 550 } 551 } 552 553 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) { 554 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 555 cld->classes_do(klass_closure); 556 } 557 } 558 559 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() { 560 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?"); 561 562 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>(); 563 564 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true); 565 ClassLoaderData* curr = _head; 566 while (curr != _saved_head) { 567 if (!curr->claimed()) { 568 array->push(curr); 569 570 if (TraceClassLoaderData) { 571 tty->print("[ClassLoaderData] found new CLD: "); 572 curr->print_value_on(tty); 573 tty->cr(); 574 } 575 } 576 577 curr = curr->_next; 578 } 579 580 return array; 581 } 582 583 #ifndef PRODUCT 584 // for debugging and hsfind(x) 585 bool ClassLoaderDataGraph::contains(address x) { 586 // I think we need the _metaspace_lock taken here because the class loader 587 // data graph could be changing while we are walking it (new entries added, 588 // new entries being unloaded, etc). 589 if (DumpSharedSpaces) { 590 // There are only two metaspaces to worry about. 591 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data(); 592 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x)); 593 } 594 595 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) { 596 return true; 597 } 598 599 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) { 600 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) { 601 return true; 602 } 603 } 604 605 // Could also be on an unloading list which is okay, ie. still allocated 606 // for a little while. 607 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) { 608 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) { 609 return true; 610 } 611 } 612 return false; 613 } 614 615 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) { 616 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 617 if (loader_data == data) { 618 return true; 619 } 620 } 621 622 return false; 623 } 624 #endif // PRODUCT 625 626 627 // Move class loader data from main list to the unloaded list for unloading 628 // and deallocation later. 629 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) { 630 ClassLoaderData* data = _head; 631 ClassLoaderData* prev = NULL; 632 bool seen_dead_loader = false; 633 // mark metadata seen on the stack and code cache so we can delete 634 // unneeded entries. 635 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class(); 636 MetadataOnStackMark md_on_stack; 637 while (data != NULL) { 638 if (data->keep_alive() || data->is_alive(is_alive_closure)) { 639 if (has_redefined_a_class) { 640 data->classes_do(InstanceKlass::purge_previous_versions); 641 } 642 data->free_deallocate_list(); 643 prev = data; 644 data = data->next(); 645 continue; 646 } 647 seen_dead_loader = true; 648 ClassLoaderData* dead = data; 649 dead->unload(); 650 data = data->next(); 651 // Remove from loader list. 652 if (prev != NULL) { 653 prev->set_next(data); 654 } else { 655 assert(dead == _head, "sanity check"); 656 _head = data; 657 } 658 dead->set_next(_unloading); 659 _unloading = dead; 660 } 661 return seen_dead_loader; 662 } 663 664 void ClassLoaderDataGraph::purge() { 665 ClassLoaderData* list = _unloading; 666 _unloading = NULL; 667 ClassLoaderData* next = list; 668 while (next != NULL) { 669 ClassLoaderData* purge_me = next; 670 next = purge_me->next(); 671 delete purge_me; 672 } 673 } 674 675 // CDS support 676 677 // Global metaspaces for writing information to the shared archive. When 678 // application CDS is supported, we may need one per metaspace, so this 679 // sort of looks like it. 680 Metaspace* ClassLoaderData::_ro_metaspace = NULL; 681 Metaspace* ClassLoaderData::_rw_metaspace = NULL; 682 static bool _shared_metaspaces_initialized = false; 683 684 // Initialize shared metaspaces (change to call from somewhere not lazily) 685 void ClassLoaderData::initialize_shared_metaspaces() { 686 assert(DumpSharedSpaces, "only use this for dumping shared spaces"); 687 assert(this == ClassLoaderData::the_null_class_loader_data(), 688 "only supported for null loader data for now"); 689 assert (!_shared_metaspaces_initialized, "only initialize once"); 690 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag); 691 _ro_metaspace = new Metaspace(_metaspace_lock, Metaspace::ROMetaspaceType); 692 _rw_metaspace = new Metaspace(_metaspace_lock, Metaspace::ReadWriteMetaspaceType); 693 _shared_metaspaces_initialized = true; 694 } 695 696 Metaspace* ClassLoaderData::ro_metaspace() { 697 assert(_ro_metaspace != NULL, "should already be initialized"); 698 return _ro_metaspace; 699 } 700 701 Metaspace* ClassLoaderData::rw_metaspace() { 702 assert(_rw_metaspace != NULL, "should already be initialized"); 703 return _rw_metaspace; 704 } 705 706 707 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() { 708 _data = ClassLoaderDataGraph::_head; 709 } 710 711 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {} 712 713 #ifndef PRODUCT 714 // callable from debugger 715 extern "C" int print_loader_data_graph() { 716 ClassLoaderDataGraph::dump_on(tty); 717 return 0; 718 } 719 720 void ClassLoaderDataGraph::verify() { 721 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 722 data->verify(); 723 } 724 } 725 726 void ClassLoaderDataGraph::dump_on(outputStream * const out) { 727 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) { 728 data->dump(out); 729 } 730 MetaspaceAux::dump(out); 731 } 732 #endif // PRODUCT 733 734 void ClassLoaderData::print_value_on(outputStream* out) const { 735 if (class_loader() == NULL) { 736 out->print("NULL class_loader"); 737 } else { 738 out->print("class loader "PTR_FORMAT, this); 739 class_loader()->print_value_on(out); 740 } 741 }