Fri, 21 Dec 2012 01:39:34 -0800
Merge
1 /*
2 * Copyright (c) 2012, 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/systemDictionary.hpp"
54 #include "code/codeCache.hpp"
55 #include "memory/metadataFactory.hpp"
56 #include "memory/metaspaceShared.hpp"
57 #include "prims/jvmtiRedefineClasses.hpp"
58 #include "runtime/jniHandles.hpp"
59 #include "runtime/mutex.hpp"
60 #include "runtime/safepoint.hpp"
61 #include "runtime/synchronizer.hpp"
62 #include "utilities/growableArray.hpp"
63 #include "utilities/ostream.hpp"
65 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
67 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_anonymous) :
68 _class_loader(h_class_loader()),
69 _is_anonymous(is_anonymous), _keep_alive(is_anonymous), // initially
70 _metaspace(NULL), _unloading(false), _klasses(NULL),
71 _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL),
72 _next(NULL), _dependencies(NULL),
73 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
74 // empty
75 }
77 void ClassLoaderData::init_dependencies(TRAPS) {
78 // Create empty dependencies array to add to. CMS requires this to be
79 // an oop so that it can track additions via card marks. We think.
80 _dependencies = (oop)oopFactory::new_objectArray(2, CHECK);
81 }
83 bool ClassLoaderData::claim() {
84 if (_claimed == 1) {
85 return false;
86 }
88 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
89 }
91 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
92 if (must_claim && !claim()) {
93 return;
94 }
96 f->do_oop(&_class_loader);
97 f->do_oop(&_dependencies);
98 _handles->oops_do(f);
99 if (klass_closure != NULL) {
100 classes_do(klass_closure);
101 }
102 }
104 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
105 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
106 klass_closure->do_klass(k);
107 }
108 }
110 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
111 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
112 if (k->oop_is_instance()) {
113 f(InstanceKlass::cast(k));
114 }
115 }
116 }
118 void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
119 ClassLoaderData * const from_cld = this;
120 ClassLoaderData * const to_cld = k->class_loader_data();
122 // Dependency to the null class loader data doesn't need to be recorded
123 // because the null class loader data never goes away.
124 if (to_cld->is_the_null_class_loader_data()) {
125 return;
126 }
128 oop to;
129 if (to_cld->is_anonymous()) {
130 // Anonymous class dependencies are through the mirror.
131 to = k->java_mirror();
132 } else {
133 to = to_cld->class_loader();
135 // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
136 // we still have to add it. The class_loader won't keep from_cld alive.
137 if (!from_cld->is_anonymous()) {
138 // Check that this dependency isn't from the same or parent class_loader
139 oop from = from_cld->class_loader();
141 oop curr = from;
142 while (curr != NULL) {
143 if (curr == to) {
144 return; // this class loader is in the parent list, no need to add it.
145 }
146 curr = java_lang_ClassLoader::parent(curr);
147 }
148 }
149 }
151 // It's a dependency we won't find through GC, add it. This is relatively rare
152 // Must handle over GC point.
153 Handle dependency(THREAD, to);
154 from_cld->add_dependency(dependency, CHECK);
155 }
158 void ClassLoaderData::add_dependency(Handle dependency, TRAPS) {
159 // Check first if this dependency is already in the list.
160 // Save a pointer to the last to add to under the lock.
161 objArrayOop ok = (objArrayOop)_dependencies;
162 objArrayOop last = NULL;
163 while (ok != NULL) {
164 last = ok;
165 if (ok->obj_at(0) == dependency()) {
166 // Don't need to add it
167 return;
168 }
169 ok = (objArrayOop)ok->obj_at(1);
170 }
172 // Must handle over GC points
173 assert (last != NULL, "dependencies should be initialized");
174 objArrayHandle last_handle(THREAD, last);
176 // Create a new dependency node with fields for (class_loader or mirror, next)
177 objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
178 deps->obj_at_put(0, dependency());
180 // Must handle over GC points
181 objArrayHandle new_dependency(THREAD, deps);
183 // Add the dependency under lock
184 locked_add_dependency(last_handle, new_dependency);
185 }
187 void ClassLoaderData::locked_add_dependency(objArrayHandle last_handle,
188 objArrayHandle new_dependency) {
190 // Have to lock and put the new dependency on the end of the dependency
191 // array so the card mark for CMS sees that this dependency is new.
192 // Can probably do this lock free with some effort.
193 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
195 oop loader_or_mirror = new_dependency->obj_at(0);
197 // Since the dependencies are only added, add to the end.
198 objArrayOop end = last_handle();
199 objArrayOop last = NULL;
200 while (end != NULL) {
201 last = end;
202 // check again if another thread added it to the end.
203 if (end->obj_at(0) == loader_or_mirror) {
204 // Don't need to add it
205 return;
206 }
207 end = (objArrayOop)end->obj_at(1);
208 }
209 assert (last != NULL, "dependencies should be initialized");
210 // fill in the first element with the oop in new_dependency.
211 if (last->obj_at(0) == NULL) {
212 last->obj_at_put(0, new_dependency->obj_at(0));
213 } else {
214 last->obj_at_put(1, new_dependency());
215 }
216 }
218 void ClassLoaderDataGraph::clear_claimed_marks() {
219 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
220 cld->clear_claimed();
221 }
222 }
224 void ClassLoaderData::add_class(Klass* k) {
225 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
226 Klass* old_value = _klasses;
227 k->set_next_link(old_value);
228 // link the new item into the list
229 _klasses = k;
231 if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
232 ResourceMark rm;
233 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
234 PTR_FORMAT " loader: " PTR_FORMAT " %s",
235 k,
236 k->external_name(),
237 k->class_loader_data(),
238 k->class_loader(),
239 loader_name());
240 }
241 }
243 // This is called by InstanceKlass::deallocate_contents() to remove the
244 // scratch_class for redefine classes. We need a lock because there it may not
245 // be called at a safepoint if there's an error.
246 void ClassLoaderData::remove_class(Klass* scratch_class) {
247 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
248 Klass* prev = NULL;
249 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
250 if (k == scratch_class) {
251 if (prev == NULL) {
252 _klasses = k->next_link();
253 } else {
254 Klass* next = k->next_link();
255 prev->set_next_link(next);
256 }
257 return;
258 }
259 prev = k;
260 }
261 ShouldNotReachHere(); // should have found this class!!
262 }
264 void ClassLoaderData::unload() {
265 _unloading = true;
267 if (TraceClassLoaderData) {
268 ResourceMark rm;
269 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this);
270 tty->print(" for instance "PTR_FORMAT" of %s", class_loader(),
271 loader_name());
272 if (is_anonymous()) {
273 tty->print(" for anonymous class "PTR_FORMAT " ", _klasses);
274 }
275 tty->print_cr("]");
276 }
277 }
279 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
280 bool alive =
281 is_anonymous() ?
282 is_alive_closure->do_object_b(_klasses->java_mirror()) :
283 class_loader() == NULL || is_alive_closure->do_object_b(class_loader());
284 assert(!alive || claimed(), "must be claimed");
285 return alive;
286 }
289 ClassLoaderData::~ClassLoaderData() {
290 Metaspace *m = _metaspace;
291 if (m != NULL) {
292 _metaspace = NULL;
293 // release the metaspace
294 delete m;
295 // release the handles
296 if (_handles != NULL) {
297 JNIHandleBlock::release_block(_handles);
298 _handles = NULL;
299 }
300 }
302 // Clear all the JNI handles for methods
303 // These aren't deallocated and are going to look like a leak, but that's
304 // needed because we can't really get rid of jmethodIDs because we don't
305 // know when native code is going to stop using them. The spec says that
306 // they're "invalid" but existing programs likely rely on their being
307 // NULL after class unloading.
308 if (_jmethod_ids != NULL) {
309 Method::clear_jmethod_ids(this);
310 }
311 // Delete lock
312 delete _metaspace_lock;
314 // Delete free list
315 if (_deallocate_list != NULL) {
316 delete _deallocate_list;
317 }
318 }
320 Metaspace* ClassLoaderData::metaspace_non_null() {
321 // If the metaspace has not been allocated, create a new one. Might want
322 // to create smaller arena for Reflection class loaders also.
323 // The reason for the delayed allocation is because some class loaders are
324 // simply for delegating with no metadata of their own.
325 if (_metaspace == NULL) {
326 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
327 // Check again if metaspace has been allocated while we were getting this lock.
328 if (_metaspace != NULL) {
329 return _metaspace;
330 }
331 if (this == the_null_class_loader_data()) {
332 assert (class_loader() == NULL, "Must be");
333 size_t word_size = Metaspace::first_chunk_word_size();
334 set_metaspace(new Metaspace(_metaspace_lock, word_size));
335 } else {
336 set_metaspace(new Metaspace(_metaspace_lock)); // default size for now.
337 }
338 }
339 return _metaspace;
340 }
342 JNIHandleBlock* ClassLoaderData::handles() const { return _handles; }
343 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
345 jobject ClassLoaderData::add_handle(Handle h) {
346 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
347 if (handles() == NULL) {
348 set_handles(JNIHandleBlock::allocate_block());
349 }
350 return handles()->allocate_handle(h());
351 }
353 // Add this metadata pointer to be freed when it's safe. This is only during
354 // class unloading because Handles might point to this metadata field.
355 void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
356 // Metadata in shared region isn't deleted.
357 if (!m->is_shared()) {
358 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
359 if (_deallocate_list == NULL) {
360 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
361 }
362 _deallocate_list->append_if_missing(m);
363 }
364 }
366 // Deallocate free metadata on the free list. How useful the PermGen was!
367 void ClassLoaderData::free_deallocate_list() {
368 // Don't need lock, at safepoint
369 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
370 if (_deallocate_list == NULL) {
371 return;
372 }
373 // Go backwards because this removes entries that are freed.
374 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
375 Metadata* m = _deallocate_list->at(i);
376 if (!m->on_stack()) {
377 _deallocate_list->remove_at(i);
378 // There are only three types of metadata that we deallocate directly.
379 // Cast them so they can be used by the template function.
380 if (m->is_method()) {
381 MetadataFactory::free_metadata(this, (Method*)m);
382 } else if (m->is_constantPool()) {
383 MetadataFactory::free_metadata(this, (ConstantPool*)m);
384 } else if (m->is_klass()) {
385 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
386 } else {
387 ShouldNotReachHere();
388 }
389 }
390 }
391 }
393 // These anonymous class loaders are to contain classes used for JSR292
394 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
395 // Add a new class loader data to the graph.
396 return ClassLoaderDataGraph::add(NULL, loader, CHECK_NULL);
397 }
399 const char* ClassLoaderData::loader_name() {
400 // Handles null class loader
401 return SystemDictionary::loader_name(class_loader());
402 }
404 #ifndef PRODUCT
405 // Define to dump klasses
406 #undef CLD_DUMP_KLASSES
408 void ClassLoaderData::dump(outputStream * const out) {
409 ResourceMark rm;
410 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
411 this, class_loader(),
412 class_loader() != NULL ? class_loader()->klass() : NULL, loader_name());
413 if (claimed()) out->print(" claimed ");
414 if (is_unloading()) out->print(" unloading ");
415 out->print(" handles " INTPTR_FORMAT, handles());
416 out->cr();
417 if (metaspace_or_null() != NULL) {
418 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null());
419 metaspace_or_null()->dump(out);
420 } else {
421 out->print_cr("metaspace: NULL");
422 }
424 #ifdef CLD_DUMP_KLASSES
425 if (Verbose) {
426 ResourceMark rm;
427 Klass* k = _klasses;
428 while (k != NULL) {
429 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
430 k->has_modified_oops(), k->has_accumulated_modified_oops());
431 k = k->next_link();
432 }
433 }
434 #endif // CLD_DUMP_KLASSES
435 #undef CLD_DUMP_KLASSES
436 if (_jmethod_ids != NULL) {
437 Method::print_jmethod_ids(this, out);
438 }
439 out->print_cr("}");
440 }
441 #endif // PRODUCT
443 void ClassLoaderData::verify() {
444 oop cl = class_loader();
446 guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
447 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
449 // Verify the integrity of the allocated space.
450 if (metaspace_or_null() != NULL) {
451 metaspace_or_null()->verify();
452 }
454 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
455 guarantee(k->class_loader_data() == this, "Must be the same");
456 k->verify();
457 }
458 }
461 // GC root of class loader data created.
462 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
463 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
464 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
467 // Add a new class loader data node to the list. Assign the newly created
468 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
469 ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader, TRAPS) {
470 // Not assigned a class loader data yet.
471 // Create one.
472 ClassLoaderData* *list_head = &_head;
473 ClassLoaderData* next = _head;
475 bool is_anonymous = (cld_addr == NULL);
476 ClassLoaderData* cld = new ClassLoaderData(loader, is_anonymous);
478 if (cld_addr != NULL) {
479 // First, Atomically set it
480 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
481 if (old != NULL) {
482 delete cld;
483 // Returns the data.
484 return old;
485 }
486 }
488 // We won the race, and therefore the task of adding the data to the list of
489 // class loader data
490 do {
491 cld->set_next(next);
492 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
493 if (exchanged == next) {
494 if (TraceClassLoaderData) {
495 ResourceMark rm;
496 tty->print("[ClassLoaderData: ");
497 tty->print("create class loader data "PTR_FORMAT, cld);
498 tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(),
499 cld->loader_name());
500 tty->print_cr("]");
501 }
502 // Create dependencies after the CLD is added to the list. Otherwise,
503 // the GC GC will not find the CLD and the _class_loader field will
504 // not be updated.
505 cld->init_dependencies(CHECK_NULL);
506 return cld;
507 }
508 next = exchanged;
509 } while (true);
511 }
513 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
514 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
515 cld->oops_do(f, klass_closure, must_claim);
516 }
517 }
519 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
520 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
521 if (cld->keep_alive()) {
522 cld->oops_do(f, klass_closure, must_claim);
523 }
524 }
525 }
527 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
528 if (ClassUnloading) {
529 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
530 // keep any special CLDs alive.
531 ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim);
532 } else {
533 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
534 }
535 }
537 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
538 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
539 cld->classes_do(klass_closure);
540 }
541 }
543 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
544 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
546 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
548 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
549 ClassLoaderData* curr = _head;
550 while (curr != _saved_head) {
551 if (!curr->claimed()) {
552 array->push(curr);
554 if (TraceClassLoaderData) {
555 tty->print("[ClassLoaderData] found new CLD: ");
556 curr->print_value_on(tty);
557 tty->cr();
558 }
559 }
561 curr = curr->_next;
562 }
564 return array;
565 }
567 #ifndef PRODUCT
568 // for debugging and hsfind(x)
569 bool ClassLoaderDataGraph::contains(address x) {
570 // I think we need the _metaspace_lock taken here because the class loader
571 // data graph could be changing while we are walking it (new entries added,
572 // new entries being unloaded, etc).
573 if (DumpSharedSpaces) {
574 // There are only two metaspaces to worry about.
575 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
576 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
577 }
579 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
580 return true;
581 }
583 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
584 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
585 return true;
586 }
587 }
589 // Could also be on an unloading list which is okay, ie. still allocated
590 // for a little while.
591 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
592 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
593 return true;
594 }
595 }
596 return false;
597 }
599 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
600 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
601 if (loader_data == data) {
602 return true;
603 }
604 }
606 return false;
607 }
608 #endif // PRODUCT
611 // Move class loader data from main list to the unloaded list for unloading
612 // and deallocation later.
613 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
614 ClassLoaderData* data = _head;
615 ClassLoaderData* prev = NULL;
616 bool seen_dead_loader = false;
617 // mark metadata seen on the stack and code cache so we can delete
618 // unneeded entries.
619 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
620 MetadataOnStackMark md_on_stack;
621 while (data != NULL) {
622 if (data->keep_alive() || data->is_alive(is_alive_closure)) {
623 if (has_redefined_a_class) {
624 data->classes_do(InstanceKlass::purge_previous_versions);
625 }
626 data->free_deallocate_list();
627 prev = data;
628 data = data->next();
629 continue;
630 }
631 seen_dead_loader = true;
632 ClassLoaderData* dead = data;
633 dead->unload();
634 data = data->next();
635 // Remove from loader list.
636 if (prev != NULL) {
637 prev->set_next(data);
638 } else {
639 assert(dead == _head, "sanity check");
640 _head = data;
641 }
642 dead->set_next(_unloading);
643 _unloading = dead;
644 }
645 return seen_dead_loader;
646 }
648 void ClassLoaderDataGraph::purge() {
649 ClassLoaderData* list = _unloading;
650 _unloading = NULL;
651 ClassLoaderData* next = list;
652 while (next != NULL) {
653 ClassLoaderData* purge_me = next;
654 next = purge_me->next();
655 delete purge_me;
656 }
657 }
659 // CDS support
661 // Global metaspaces for writing information to the shared archive. When
662 // application CDS is supported, we may need one per metaspace, so this
663 // sort of looks like it.
664 Metaspace* ClassLoaderData::_ro_metaspace = NULL;
665 Metaspace* ClassLoaderData::_rw_metaspace = NULL;
666 static bool _shared_metaspaces_initialized = false;
668 // Initialize shared metaspaces (change to call from somewhere not lazily)
669 void ClassLoaderData::initialize_shared_metaspaces() {
670 assert(DumpSharedSpaces, "only use this for dumping shared spaces");
671 assert(this == ClassLoaderData::the_null_class_loader_data(),
672 "only supported for null loader data for now");
673 assert (!_shared_metaspaces_initialized, "only initialize once");
674 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
675 _ro_metaspace = new Metaspace(_metaspace_lock, SharedReadOnlySize/wordSize);
676 _rw_metaspace = new Metaspace(_metaspace_lock, SharedReadWriteSize/wordSize);
677 _shared_metaspaces_initialized = true;
678 }
680 Metaspace* ClassLoaderData::ro_metaspace() {
681 assert(_ro_metaspace != NULL, "should already be initialized");
682 return _ro_metaspace;
683 }
685 Metaspace* ClassLoaderData::rw_metaspace() {
686 assert(_rw_metaspace != NULL, "should already be initialized");
687 return _rw_metaspace;
688 }
691 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
692 _data = ClassLoaderDataGraph::_head;
693 }
695 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
697 #ifndef PRODUCT
698 // callable from debugger
699 extern "C" int print_loader_data_graph() {
700 ClassLoaderDataGraph::dump_on(tty);
701 return 0;
702 }
704 void ClassLoaderDataGraph::verify() {
705 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
706 data->verify();
707 }
708 }
710 void ClassLoaderDataGraph::dump_on(outputStream * const out) {
711 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
712 data->dump(out);
713 }
714 MetaspaceAux::dump(out);
715 }
717 void ClassLoaderData::print_value_on(outputStream* out) const {
718 if (class_loader() == NULL) {
719 out->print_cr("NULL class_loader");
720 } else {
721 out->print("class loader "PTR_FORMAT, this);
722 class_loader()->print_value_on(out);
723 }
724 }
725 #endif // PRODUCT