Wed, 24 Apr 2013 16:19:35 -0400
8011803: release_C_heap_structures is never called for anonymous classes.
Summary: Call this function from the ClassLoaderData destructor instead of the system dictionary walk.
Reviewed-by: stefank, mgerdin
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 */
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().
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"
66 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
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(),
74 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
75 // empty
76 }
78 void ClassLoaderData::init_dependencies(TRAPS) {
79 _dependencies.init(CHECK);
80 }
82 void ClassLoaderData::Dependencies::init(TRAPS) {
83 // Create empty dependencies array to add to. CMS requires this to be
84 // an oop so that it can track additions via card marks. We think.
85 _list_head = oopFactory::new_objectArray(2, CHECK);
86 }
88 bool ClassLoaderData::claim() {
89 if (_claimed == 1) {
90 return false;
91 }
93 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
94 }
96 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
97 if (must_claim && !claim()) {
98 return;
99 }
101 f->do_oop(&_class_loader);
102 _dependencies.oops_do(f);
103 _handles->oops_do(f);
104 if (klass_closure != NULL) {
105 classes_do(klass_closure);
106 }
107 }
109 void ClassLoaderData::Dependencies::oops_do(OopClosure* f) {
110 f->do_oop((oop*)&_list_head);
111 }
113 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
114 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
115 klass_closure->do_klass(k);
116 assert(k != k->next_link(), "no loops!");
117 }
118 }
120 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
121 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
122 if (k->oop_is_instance()) {
123 f(InstanceKlass::cast(k));
124 }
125 assert(k != k->next_link(), "no loops!");
126 }
127 }
129 void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
130 ClassLoaderData * const from_cld = this;
131 ClassLoaderData * const to_cld = k->class_loader_data();
133 // Dependency to the null class loader data doesn't need to be recorded
134 // because the null class loader data never goes away.
135 if (to_cld->is_the_null_class_loader_data()) {
136 return;
137 }
139 oop to;
140 if (to_cld->is_anonymous()) {
141 // Anonymous class dependencies are through the mirror.
142 to = k->java_mirror();
143 } else {
144 to = to_cld->class_loader();
146 // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
147 // we still have to add it. The class_loader won't keep from_cld alive.
148 if (!from_cld->is_anonymous()) {
149 // Check that this dependency isn't from the same or parent class_loader
150 oop from = from_cld->class_loader();
152 oop curr = from;
153 while (curr != NULL) {
154 if (curr == to) {
155 return; // this class loader is in the parent list, no need to add it.
156 }
157 curr = java_lang_ClassLoader::parent(curr);
158 }
159 }
160 }
162 // It's a dependency we won't find through GC, add it. This is relatively rare
163 // Must handle over GC point.
164 Handle dependency(THREAD, to);
165 from_cld->_dependencies.add(dependency, CHECK);
166 }
169 void ClassLoaderData::Dependencies::add(Handle dependency, TRAPS) {
170 // Check first if this dependency is already in the list.
171 // Save a pointer to the last to add to under the lock.
172 objArrayOop ok = _list_head;
173 objArrayOop last = NULL;
174 while (ok != NULL) {
175 last = ok;
176 if (ok->obj_at(0) == dependency()) {
177 // Don't need to add it
178 return;
179 }
180 ok = (objArrayOop)ok->obj_at(1);
181 }
183 // Must handle over GC points
184 assert (last != NULL, "dependencies should be initialized");
185 objArrayHandle last_handle(THREAD, last);
187 // Create a new dependency node with fields for (class_loader or mirror, next)
188 objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
189 deps->obj_at_put(0, dependency());
191 // Must handle over GC points
192 objArrayHandle new_dependency(THREAD, deps);
194 // Add the dependency under lock
195 locked_add(last_handle, new_dependency, THREAD);
196 }
198 void ClassLoaderData::Dependencies::locked_add(objArrayHandle last_handle,
199 objArrayHandle new_dependency,
200 Thread* THREAD) {
202 // Have to lock and put the new dependency on the end of the dependency
203 // array so the card mark for CMS sees that this dependency is new.
204 // Can probably do this lock free with some effort.
205 ObjectLocker ol(Handle(THREAD, _list_head), THREAD);
207 oop loader_or_mirror = new_dependency->obj_at(0);
209 // Since the dependencies are only added, add to the end.
210 objArrayOop end = last_handle();
211 objArrayOop last = NULL;
212 while (end != NULL) {
213 last = end;
214 // check again if another thread added it to the end.
215 if (end->obj_at(0) == loader_or_mirror) {
216 // Don't need to add it
217 return;
218 }
219 end = (objArrayOop)end->obj_at(1);
220 }
221 assert (last != NULL, "dependencies should be initialized");
222 // fill in the first element with the oop in new_dependency.
223 if (last->obj_at(0) == NULL) {
224 last->obj_at_put(0, new_dependency->obj_at(0));
225 } else {
226 last->obj_at_put(1, new_dependency());
227 }
228 }
230 void ClassLoaderDataGraph::clear_claimed_marks() {
231 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
232 cld->clear_claimed();
233 }
234 }
236 void ClassLoaderData::add_class(Klass* k) {
237 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
238 Klass* old_value = _klasses;
239 k->set_next_link(old_value);
240 // link the new item into the list
241 _klasses = k;
243 if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
244 ResourceMark rm;
245 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
246 PTR_FORMAT " loader: " PTR_FORMAT " %s",
247 k,
248 k->external_name(),
249 k->class_loader_data(),
250 k->class_loader(),
251 loader_name());
252 }
253 }
255 // This is called by InstanceKlass::deallocate_contents() to remove the
256 // scratch_class for redefine classes. We need a lock because there it may not
257 // be called at a safepoint if there's an error.
258 void ClassLoaderData::remove_class(Klass* scratch_class) {
259 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
260 Klass* prev = NULL;
261 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
262 if (k == scratch_class) {
263 if (prev == NULL) {
264 _klasses = k->next_link();
265 } else {
266 Klass* next = k->next_link();
267 prev->set_next_link(next);
268 }
269 return;
270 }
271 prev = k;
272 assert(k != k->next_link(), "no loops!");
273 }
274 ShouldNotReachHere(); // should have found this class!!
275 }
277 void ClassLoaderData::unload() {
278 _unloading = true;
280 // Tell serviceability tools these classes are unloading
281 classes_do(InstanceKlass::notify_unload_class);
283 if (TraceClassLoaderData) {
284 ResourceMark rm;
285 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this);
286 tty->print(" for instance "PTR_FORMAT" of %s", class_loader(),
287 loader_name());
288 if (is_anonymous()) {
289 tty->print(" for anonymous class "PTR_FORMAT " ", _klasses);
290 }
291 tty->print_cr("]");
292 }
293 }
295 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
296 bool alive =
297 is_anonymous() ?
298 is_alive_closure->do_object_b(_klasses->java_mirror()) :
299 class_loader() == NULL || is_alive_closure->do_object_b(class_loader());
300 assert(!alive || claimed(), "must be claimed");
301 return alive;
302 }
305 ClassLoaderData::~ClassLoaderData() {
306 // Release C heap structures for all the classes.
307 classes_do(InstanceKlass::release_C_heap_structures);
309 Metaspace *m = _metaspace;
310 if (m != NULL) {
311 _metaspace = NULL;
312 // release the metaspace
313 delete m;
314 // release the handles
315 if (_handles != NULL) {
316 JNIHandleBlock::release_block(_handles);
317 _handles = NULL;
318 }
319 }
321 // Clear all the JNI handles for methods
322 // These aren't deallocated and are going to look like a leak, but that's
323 // needed because we can't really get rid of jmethodIDs because we don't
324 // know when native code is going to stop using them. The spec says that
325 // they're "invalid" but existing programs likely rely on their being
326 // NULL after class unloading.
327 if (_jmethod_ids != NULL) {
328 Method::clear_jmethod_ids(this);
329 }
330 // Delete lock
331 delete _metaspace_lock;
333 // Delete free list
334 if (_deallocate_list != NULL) {
335 delete _deallocate_list;
336 }
337 }
339 /**
340 * Returns true if this class loader data is for the extension class loader.
341 */
342 bool ClassLoaderData::is_ext_class_loader_data() const {
343 return SystemDictionary::is_ext_class_loader(class_loader());
344 }
346 Metaspace* ClassLoaderData::metaspace_non_null() {
347 assert(!DumpSharedSpaces, "wrong metaspace!");
348 // If the metaspace has not been allocated, create a new one. Might want
349 // to create smaller arena for Reflection class loaders also.
350 // The reason for the delayed allocation is because some class loaders are
351 // simply for delegating with no metadata of their own.
352 if (_metaspace == NULL) {
353 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
354 // Check again if metaspace has been allocated while we were getting this lock.
355 if (_metaspace != NULL) {
356 return _metaspace;
357 }
358 if (this == the_null_class_loader_data()) {
359 assert (class_loader() == NULL, "Must be");
360 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::BootMetaspaceType));
361 } else if (is_anonymous()) {
362 if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
363 tty->print_cr("is_anonymous: %s", class_loader()->klass()->internal_name());
364 }
365 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::AnonymousMetaspaceType));
366 } else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) {
367 if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
368 tty->print_cr("is_reflection: %s", class_loader()->klass()->internal_name());
369 }
370 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::ReflectionMetaspaceType));
371 } else {
372 set_metaspace(new Metaspace(_metaspace_lock, Metaspace::StandardMetaspaceType));
373 }
374 }
375 return _metaspace;
376 }
378 JNIHandleBlock* ClassLoaderData::handles() const { return _handles; }
379 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
381 jobject ClassLoaderData::add_handle(Handle h) {
382 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
383 if (handles() == NULL) {
384 set_handles(JNIHandleBlock::allocate_block());
385 }
386 return handles()->allocate_handle(h());
387 }
389 // Add this metadata pointer to be freed when it's safe. This is only during
390 // class unloading because Handles might point to this metadata field.
391 void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
392 // Metadata in shared region isn't deleted.
393 if (!m->is_shared()) {
394 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
395 if (_deallocate_list == NULL) {
396 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
397 }
398 _deallocate_list->append_if_missing(m);
399 }
400 }
402 // Deallocate free metadata on the free list. How useful the PermGen was!
403 void ClassLoaderData::free_deallocate_list() {
404 // Don't need lock, at safepoint
405 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
406 if (_deallocate_list == NULL) {
407 return;
408 }
409 // Go backwards because this removes entries that are freed.
410 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
411 Metadata* m = _deallocate_list->at(i);
412 if (!m->on_stack()) {
413 _deallocate_list->remove_at(i);
414 // There are only three types of metadata that we deallocate directly.
415 // Cast them so they can be used by the template function.
416 if (m->is_method()) {
417 MetadataFactory::free_metadata(this, (Method*)m);
418 } else if (m->is_constantPool()) {
419 MetadataFactory::free_metadata(this, (ConstantPool*)m);
420 } else if (m->is_klass()) {
421 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
422 } else {
423 ShouldNotReachHere();
424 }
425 }
426 }
427 }
429 // These anonymous class loaders are to contain classes used for JSR292
430 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
431 // Add a new class loader data to the graph.
432 return ClassLoaderDataGraph::add(NULL, loader, CHECK_NULL);
433 }
435 const char* ClassLoaderData::loader_name() {
436 // Handles null class loader
437 return SystemDictionary::loader_name(class_loader());
438 }
440 #ifndef PRODUCT
441 // Define to dump klasses
442 #undef CLD_DUMP_KLASSES
444 void ClassLoaderData::dump(outputStream * const out) {
445 ResourceMark rm;
446 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
447 this, class_loader(),
448 class_loader() != NULL ? class_loader()->klass() : NULL, loader_name());
449 if (claimed()) out->print(" claimed ");
450 if (is_unloading()) out->print(" unloading ");
451 out->print(" handles " INTPTR_FORMAT, handles());
452 out->cr();
453 if (metaspace_or_null() != NULL) {
454 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null());
455 metaspace_or_null()->dump(out);
456 } else {
457 out->print_cr("metaspace: NULL");
458 }
460 #ifdef CLD_DUMP_KLASSES
461 if (Verbose) {
462 ResourceMark rm;
463 Klass* k = _klasses;
464 while (k != NULL) {
465 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
466 k->has_modified_oops(), k->has_accumulated_modified_oops());
467 assert(k != k->next_link(), "no loops!");
468 k = k->next_link();
469 }
470 }
471 #endif // CLD_DUMP_KLASSES
472 #undef CLD_DUMP_KLASSES
473 if (_jmethod_ids != NULL) {
474 Method::print_jmethod_ids(this, out);
475 }
476 out->print_cr("}");
477 }
478 #endif // PRODUCT
480 void ClassLoaderData::verify() {
481 oop cl = class_loader();
483 guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
484 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
486 // Verify the integrity of the allocated space.
487 if (metaspace_or_null() != NULL) {
488 metaspace_or_null()->verify();
489 }
491 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
492 guarantee(k->class_loader_data() == this, "Must be the same");
493 k->verify();
494 assert(k != k->next_link(), "no loops!");
495 }
496 }
499 // GC root of class loader data created.
500 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
501 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
502 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
505 // Add a new class loader data node to the list. Assign the newly created
506 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
507 ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader, TRAPS) {
508 // Not assigned a class loader data yet.
509 // Create one.
510 ClassLoaderData* *list_head = &_head;
511 ClassLoaderData* next = _head;
513 bool is_anonymous = (cld_addr == NULL);
514 ClassLoaderData* cld = new ClassLoaderData(loader, is_anonymous);
516 if (cld_addr != NULL) {
517 // First, Atomically set it
518 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
519 if (old != NULL) {
520 delete cld;
521 // Returns the data.
522 return old;
523 }
524 }
526 // We won the race, and therefore the task of adding the data to the list of
527 // class loader data
528 do {
529 cld->set_next(next);
530 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
531 if (exchanged == next) {
532 if (TraceClassLoaderData) {
533 ResourceMark rm;
534 tty->print("[ClassLoaderData: ");
535 tty->print("create class loader data "PTR_FORMAT, cld);
536 tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(),
537 cld->loader_name());
538 tty->print_cr("]");
539 }
540 // Create dependencies after the CLD is added to the list. Otherwise,
541 // the GC GC will not find the CLD and the _class_loader field will
542 // not be updated.
543 cld->init_dependencies(CHECK_NULL);
544 return cld;
545 }
546 next = exchanged;
547 } while (true);
549 }
551 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
552 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
553 cld->oops_do(f, klass_closure, must_claim);
554 }
555 }
557 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
558 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
559 if (cld->keep_alive()) {
560 cld->oops_do(f, klass_closure, must_claim);
561 }
562 }
563 }
565 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
566 if (ClassUnloading) {
567 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
568 // keep any special CLDs alive.
569 ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim);
570 } else {
571 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
572 }
573 }
575 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
576 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
577 cld->classes_do(klass_closure);
578 }
579 }
581 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
582 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
584 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
586 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
587 ClassLoaderData* curr = _head;
588 while (curr != _saved_head) {
589 if (!curr->claimed()) {
590 array->push(curr);
592 if (TraceClassLoaderData) {
593 tty->print("[ClassLoaderData] found new CLD: ");
594 curr->print_value_on(tty);
595 tty->cr();
596 }
597 }
599 curr = curr->_next;
600 }
602 return array;
603 }
605 #ifndef PRODUCT
606 // for debugging and hsfind(x)
607 bool ClassLoaderDataGraph::contains(address x) {
608 // I think we need the _metaspace_lock taken here because the class loader
609 // data graph could be changing while we are walking it (new entries added,
610 // new entries being unloaded, etc).
611 if (DumpSharedSpaces) {
612 // There are only two metaspaces to worry about.
613 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
614 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
615 }
617 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
618 return true;
619 }
621 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
622 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
623 return true;
624 }
625 }
627 // Could also be on an unloading list which is okay, ie. still allocated
628 // for a little while.
629 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
630 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
631 return true;
632 }
633 }
634 return false;
635 }
637 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
638 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
639 if (loader_data == data) {
640 return true;
641 }
642 }
644 return false;
645 }
646 #endif // PRODUCT
649 // Move class loader data from main list to the unloaded list for unloading
650 // and deallocation later.
651 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
652 ClassLoaderData* data = _head;
653 ClassLoaderData* prev = NULL;
654 bool seen_dead_loader = false;
655 // mark metadata seen on the stack and code cache so we can delete
656 // unneeded entries.
657 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
658 MetadataOnStackMark md_on_stack;
659 while (data != NULL) {
660 if (data->keep_alive() || data->is_alive(is_alive_closure)) {
661 if (has_redefined_a_class) {
662 data->classes_do(InstanceKlass::purge_previous_versions);
663 }
664 data->free_deallocate_list();
665 prev = data;
666 data = data->next();
667 continue;
668 }
669 seen_dead_loader = true;
670 ClassLoaderData* dead = data;
671 dead->unload();
672 data = data->next();
673 // Remove from loader list.
674 if (prev != NULL) {
675 prev->set_next(data);
676 } else {
677 assert(dead == _head, "sanity check");
678 _head = data;
679 }
680 dead->set_next(_unloading);
681 _unloading = dead;
682 }
683 return seen_dead_loader;
684 }
686 void ClassLoaderDataGraph::purge() {
687 ClassLoaderData* list = _unloading;
688 _unloading = NULL;
689 ClassLoaderData* next = list;
690 while (next != NULL) {
691 ClassLoaderData* purge_me = next;
692 next = purge_me->next();
693 delete purge_me;
694 }
695 }
697 // CDS support
699 // Global metaspaces for writing information to the shared archive. When
700 // application CDS is supported, we may need one per metaspace, so this
701 // sort of looks like it.
702 Metaspace* ClassLoaderData::_ro_metaspace = NULL;
703 Metaspace* ClassLoaderData::_rw_metaspace = NULL;
704 static bool _shared_metaspaces_initialized = false;
706 // Initialize shared metaspaces (change to call from somewhere not lazily)
707 void ClassLoaderData::initialize_shared_metaspaces() {
708 assert(DumpSharedSpaces, "only use this for dumping shared spaces");
709 assert(this == ClassLoaderData::the_null_class_loader_data(),
710 "only supported for null loader data for now");
711 assert (!_shared_metaspaces_initialized, "only initialize once");
712 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
713 _ro_metaspace = new Metaspace(_metaspace_lock, Metaspace::ROMetaspaceType);
714 _rw_metaspace = new Metaspace(_metaspace_lock, Metaspace::ReadWriteMetaspaceType);
715 _shared_metaspaces_initialized = true;
716 }
718 Metaspace* ClassLoaderData::ro_metaspace() {
719 assert(_ro_metaspace != NULL, "should already be initialized");
720 return _ro_metaspace;
721 }
723 Metaspace* ClassLoaderData::rw_metaspace() {
724 assert(_rw_metaspace != NULL, "should already be initialized");
725 return _rw_metaspace;
726 }
729 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
730 _data = ClassLoaderDataGraph::_head;
731 }
733 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
735 #ifndef PRODUCT
736 // callable from debugger
737 extern "C" int print_loader_data_graph() {
738 ClassLoaderDataGraph::dump_on(tty);
739 return 0;
740 }
742 void ClassLoaderDataGraph::verify() {
743 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
744 data->verify();
745 }
746 }
748 void ClassLoaderDataGraph::dump_on(outputStream * const out) {
749 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
750 data->dump(out);
751 }
752 MetaspaceAux::dump(out);
753 }
754 #endif // PRODUCT
756 void ClassLoaderData::print_value_on(outputStream* out) const {
757 if (class_loader() == NULL) {
758 out->print("NULL class_loader");
759 } else {
760 out->print("class loader "PTR_FORMAT, this);
761 class_loader()->print_value_on(out);
762 }
763 }