Thu, 29 Nov 2012 16:50:29 -0500
8000662: NPG: nashorn ant clean test262 out-of-memory with Java heap
Summary: Add ClassLoaderData object for each anonymous class with metaspaces to allocate in.
Reviewed-by: twisti, jrose, stefank
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) : _class_loader(h_class_loader()),
68 _metaspace(NULL), _unloading(false), _keep_alive(false), _klasses(NULL),
69 _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL),
70 _next(NULL), _dependencies(NULL),
71 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
72 // empty
73 }
75 void ClassLoaderData::init_dependencies(TRAPS) {
76 // Create empty dependencies array to add to. CMS requires this to be
77 // an oop so that it can track additions via card marks. We think.
78 _dependencies = (oop)oopFactory::new_objectArray(2, CHECK);
79 }
81 bool ClassLoaderData::claim() {
82 if (_claimed == 1) {
83 return false;
84 }
86 return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
87 }
89 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
90 if (must_claim && !claim()) {
91 return;
92 }
94 f->do_oop(&_class_loader);
95 f->do_oop(&_dependencies);
96 _handles->oops_do(f);
97 if (klass_closure != NULL) {
98 classes_do(klass_closure);
99 }
100 }
102 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
103 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
104 klass_closure->do_klass(k);
105 }
106 }
108 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
109 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
110 if (k->oop_is_instance()) {
111 f(InstanceKlass::cast(k));
112 }
113 }
114 }
116 void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
117 ClassLoaderData * const from_cld = this;
118 ClassLoaderData * const to_cld = k->class_loader_data();
120 // Dependency to the null class loader data doesn't need to be recorded
121 // because the null class loader data never goes away.
122 if (to_cld->is_the_null_class_loader_data()) {
123 return;
124 }
126 oop to;
127 if (to_cld->is_anonymous()) {
128 // Anonymous class dependencies are through the mirror.
129 to = k->java_mirror();
130 } else {
131 to = to_cld->class_loader();
133 // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
134 // we still have to add it. The class_loader won't keep from_cld alive.
135 if (!from_cld->is_anonymous()) {
136 // Check that this dependency isn't from the same or parent class_loader
137 oop from = from_cld->class_loader();
139 oop curr = from;
140 while (curr != NULL) {
141 if (curr == to) {
142 return; // this class loader is in the parent list, no need to add it.
143 }
144 curr = java_lang_ClassLoader::parent(curr);
145 }
146 }
147 }
149 // It's a dependency we won't find through GC, add it. This is relatively rare
150 // Must handle over GC point.
151 Handle dependency(THREAD, to);
152 from_cld->add_dependency(dependency, CHECK);
153 }
156 void ClassLoaderData::add_dependency(Handle dependency, TRAPS) {
157 // Check first if this dependency is already in the list.
158 // Save a pointer to the last to add to under the lock.
159 objArrayOop ok = (objArrayOop)_dependencies;
160 objArrayOop last = NULL;
161 while (ok != NULL) {
162 last = ok;
163 if (ok->obj_at(0) == dependency()) {
164 // Don't need to add it
165 return;
166 }
167 ok = (objArrayOop)ok->obj_at(1);
168 }
170 // Create a new dependency node with fields for (class_loader or mirror, next)
171 objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
172 deps->obj_at_put(0, dependency());
174 // Must handle over more GC points
175 objArrayHandle new_dependency(THREAD, deps);
177 // Add the dependency under lock
178 assert (last != NULL, "dependencies should be initialized");
179 objArrayHandle last_handle(THREAD, last);
180 locked_add_dependency(last_handle, new_dependency);
181 }
183 void ClassLoaderData::locked_add_dependency(objArrayHandle last_handle,
184 objArrayHandle new_dependency) {
186 // Have to lock and put the new dependency on the end of the dependency
187 // array so the card mark for CMS sees that this dependency is new.
188 // Can probably do this lock free with some effort.
189 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
191 oop loader_or_mirror = new_dependency->obj_at(0);
193 // Since the dependencies are only added, add to the end.
194 objArrayOop end = last_handle();
195 objArrayOop last = NULL;
196 while (end != NULL) {
197 last = end;
198 // check again if another thread added it to the end.
199 if (end->obj_at(0) == loader_or_mirror) {
200 // Don't need to add it
201 return;
202 }
203 end = (objArrayOop)end->obj_at(1);
204 }
205 assert (last != NULL, "dependencies should be initialized");
206 // fill in the first element with the oop in new_dependency.
207 if (last->obj_at(0) == NULL) {
208 last->obj_at_put(0, new_dependency->obj_at(0));
209 } else {
210 last->obj_at_put(1, new_dependency());
211 }
212 }
214 void ClassLoaderDataGraph::clear_claimed_marks() {
215 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
216 cld->clear_claimed();
217 }
218 }
220 void ClassLoaderData::add_class(Klass* k) {
221 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
222 Klass* old_value = _klasses;
223 k->set_next_link(old_value);
224 // link the new item into the list
225 _klasses = k;
227 if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
228 ResourceMark rm;
229 tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
230 PTR_FORMAT " loader: " PTR_FORMAT " %s",
231 k,
232 k->external_name(),
233 k->class_loader_data(),
234 k->class_loader(),
235 loader_name());
236 }
237 }
239 // This is called by InstanceKlass::deallocate_contents() to remove the
240 // scratch_class for redefine classes. We need a lock because there it may not
241 // be called at a safepoint if there's an error.
242 void ClassLoaderData::remove_class(Klass* scratch_class) {
243 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
244 Klass* prev = NULL;
245 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
246 if (k == scratch_class) {
247 if (prev == NULL) {
248 _klasses = k->next_link();
249 } else {
250 Klass* next = k->next_link();
251 prev->set_next_link(next);
252 }
253 return;
254 }
255 prev = k;
256 }
257 ShouldNotReachHere(); // should have found this class!!
258 }
261 bool ClassLoaderData::is_anonymous() const {
262 Klass* k = _klasses;
263 return (_keep_alive || (k != NULL && k->oop_is_instance() &&
264 InstanceKlass::cast(k)->is_anonymous()));
265 }
267 void ClassLoaderData::unload() {
268 _unloading = true;
270 if (TraceClassLoaderData) {
271 ResourceMark rm;
272 tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, this);
273 tty->print(" for instance "PTR_FORMAT" of %s", class_loader(),
274 loader_name());
275 if (is_anonymous()) {
276 tty->print(" for anonymous class "PTR_FORMAT " ", _klasses);
277 }
278 tty->print_cr("]");
279 }
280 }
282 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
283 bool alive =
284 is_anonymous() ?
285 is_alive_closure->do_object_b(_klasses->java_mirror()) :
286 class_loader() == NULL || is_alive_closure->do_object_b(class_loader());
287 assert(!alive || claimed(), "must be claimed");
288 return alive;
289 }
292 ClassLoaderData::~ClassLoaderData() {
293 Metaspace *m = _metaspace;
294 if (m != NULL) {
295 _metaspace = NULL;
296 // release the metaspace
297 delete m;
298 // release the handles
299 if (_handles != NULL) {
300 JNIHandleBlock::release_block(_handles);
301 _handles = NULL;
302 }
303 }
305 // Clear all the JNI handles for methods
306 // These aren't deallocated and are going to look like a leak, but that's
307 // needed because we can't really get rid of jmethodIDs because we don't
308 // know when native code is going to stop using them. The spec says that
309 // they're "invalid" but existing programs likely rely on their being
310 // NULL after class unloading.
311 if (_jmethod_ids != NULL) {
312 Method::clear_jmethod_ids(this);
313 }
314 // Delete lock
315 delete _metaspace_lock;
317 // Delete free list
318 if (_deallocate_list != NULL) {
319 delete _deallocate_list;
320 }
321 }
323 Metaspace* ClassLoaderData::metaspace_non_null() {
324 // If the metaspace has not been allocated, create a new one. Might want
325 // to create smaller arena for Reflection class loaders also.
326 // The reason for the delayed allocation is because some class loaders are
327 // simply for delegating with no metadata of their own.
328 if (_metaspace == NULL) {
329 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
330 // Check again if metaspace has been allocated while we were getting this lock.
331 if (_metaspace != NULL) {
332 return _metaspace;
333 }
334 if (this == the_null_class_loader_data()) {
335 assert (class_loader() == NULL, "Must be");
336 size_t word_size = Metaspace::first_chunk_word_size();
337 set_metaspace(new Metaspace(_metaspace_lock, word_size));
338 } else {
339 set_metaspace(new Metaspace(_metaspace_lock)); // default size for now.
340 }
341 }
342 return _metaspace;
343 }
345 JNIHandleBlock* ClassLoaderData::handles() const { return _handles; }
346 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
348 jobject ClassLoaderData::add_handle(Handle h) {
349 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
350 if (handles() == NULL) {
351 set_handles(JNIHandleBlock::allocate_block());
352 }
353 return handles()->allocate_handle(h());
354 }
356 // Add this metadata pointer to be freed when it's safe. This is only during
357 // class unloading because Handles might point to this metadata field.
358 void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
359 // Metadata in shared region isn't deleted.
360 if (!m->is_shared()) {
361 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
362 if (_deallocate_list == NULL) {
363 _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
364 }
365 _deallocate_list->append_if_missing(m);
366 }
367 }
369 // Deallocate free metadata on the free list. How useful the PermGen was!
370 void ClassLoaderData::free_deallocate_list() {
371 // Don't need lock, at safepoint
372 assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
373 if (_deallocate_list == NULL) {
374 return;
375 }
376 // Go backwards because this removes entries that are freed.
377 for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
378 Metadata* m = _deallocate_list->at(i);
379 if (!m->on_stack()) {
380 _deallocate_list->remove_at(i);
381 // There are only three types of metadata that we deallocate directly.
382 // Cast them so they can be used by the template function.
383 if (m->is_method()) {
384 MetadataFactory::free_metadata(this, (Method*)m);
385 } else if (m->is_constantPool()) {
386 MetadataFactory::free_metadata(this, (ConstantPool*)m);
387 } else if (m->is_klass()) {
388 MetadataFactory::free_metadata(this, (InstanceKlass*)m);
389 } else {
390 ShouldNotReachHere();
391 }
392 }
393 }
394 }
396 // These anonymous class loaders are to contain classes used for JSR292
397 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
398 // Add a new class loader data to the graph.
399 ClassLoaderData* cld = ClassLoaderDataGraph::add(NULL, loader, CHECK_NULL);
400 return cld;
401 }
403 const char* ClassLoaderData::loader_name() {
404 // Handles null class loader
405 return SystemDictionary::loader_name(class_loader());
406 }
408 #ifndef PRODUCT
409 // Define to dump klasses
410 #undef CLD_DUMP_KLASSES
412 void ClassLoaderData::dump(outputStream * const out) {
413 ResourceMark rm;
414 out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
415 this, class_loader(),
416 class_loader() != NULL ? class_loader()->klass() : NULL, loader_name());
417 if (claimed()) out->print(" claimed ");
418 if (is_unloading()) out->print(" unloading ");
419 out->print(" handles " INTPTR_FORMAT, handles());
420 out->cr();
421 if (metaspace_or_null() != NULL) {
422 out->print_cr("metaspace: " PTR_FORMAT, metaspace_or_null());
423 metaspace_or_null()->dump(out);
424 } else {
425 out->print_cr("metaspace: NULL");
426 }
428 #ifdef CLD_DUMP_KLASSES
429 if (Verbose) {
430 ResourceMark rm;
431 Klass* k = _klasses;
432 while (k != NULL) {
433 out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
434 k->has_modified_oops(), k->has_accumulated_modified_oops());
435 k = k->next_link();
436 }
437 }
438 #endif // CLD_DUMP_KLASSES
439 #undef CLD_DUMP_KLASSES
440 if (_jmethod_ids != NULL) {
441 Method::print_jmethod_ids(this, out);
442 }
443 out->print_cr("}");
444 }
445 #endif // PRODUCT
447 void ClassLoaderData::verify() {
448 oop cl = class_loader();
450 guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
451 guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
453 // Verify the integrity of the allocated space.
454 if (metaspace_or_null() != NULL) {
455 metaspace_or_null()->verify();
456 }
458 for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
459 guarantee(k->class_loader_data() == this, "Must be the same");
460 k->verify();
461 }
462 }
465 // GC root of class loader data created.
466 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
467 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
468 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
471 // Add a new class loader data node to the list. Assign the newly created
472 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
473 ClassLoaderData* ClassLoaderDataGraph::add(ClassLoaderData** cld_addr, Handle loader, TRAPS) {
474 // Not assigned a class loader data yet.
475 // Create one.
476 ClassLoaderData* *list_head = &_head;
477 ClassLoaderData* next = _head;
478 ClassLoaderData* cld = new ClassLoaderData(loader);
480 if (cld_addr != NULL) {
481 // First, Atomically set it
482 ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
483 if (old != NULL) {
484 delete cld;
485 // Returns the data.
486 return old;
487 }
488 } else {
489 // Disallow unloading for this CLD during initialization if there is no
490 // class_loader oop to link this to.
491 cld->set_keep_alive(true);
492 }
494 // We won the race, and therefore the task of adding the data to the list of
495 // class loader data
496 do {
497 cld->set_next(next);
498 ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
499 if (exchanged == next) {
500 if (TraceClassLoaderData) {
501 ResourceMark rm;
502 tty->print("[ClassLoaderData: ");
503 tty->print("create class loader data "PTR_FORMAT, cld);
504 tty->print(" for instance "PTR_FORMAT" of %s", cld->class_loader(),
505 cld->loader_name());
506 tty->print_cr("]");
507 }
508 // Create dependencies after the CLD is added to the list. Otherwise,
509 // the GC GC will not find the CLD and the _class_loader field will
510 // not be updated.
511 cld->init_dependencies(CHECK_NULL);
512 return cld;
513 }
514 next = exchanged;
515 } while (true);
517 }
519 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
520 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
521 cld->oops_do(f, klass_closure, must_claim);
522 }
523 }
525 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
526 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
527 if (cld->keep_alive()) {
528 cld->oops_do(f, klass_closure, must_claim);
529 }
530 }
531 }
533 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
534 if (ClassUnloading) {
535 ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
536 // keep any special CLDs alive.
537 ClassLoaderDataGraph::keep_alive_oops_do(f, klass_closure, must_claim);
538 } else {
539 ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
540 }
541 }
543 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
544 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
545 cld->classes_do(klass_closure);
546 }
547 }
549 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
550 assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
552 GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
554 // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
555 ClassLoaderData* curr = _head;
556 while (curr != _saved_head) {
557 if (!curr->claimed()) {
558 array->push(curr);
560 if (TraceClassLoaderData) {
561 tty->print("[ClassLoaderData] found new CLD: ");
562 curr->print_value_on(tty);
563 tty->cr();
564 }
565 }
567 curr = curr->_next;
568 }
570 return array;
571 }
573 #ifndef PRODUCT
574 // for debugging and hsfind(x)
575 bool ClassLoaderDataGraph::contains(address x) {
576 // I think we need the _metaspace_lock taken here because the class loader
577 // data graph could be changing while we are walking it (new entries added,
578 // new entries being unloaded, etc).
579 if (DumpSharedSpaces) {
580 // There are only two metaspaces to worry about.
581 ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
582 return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
583 }
585 if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
586 return true;
587 }
589 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
590 if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
591 return true;
592 }
593 }
595 // Could also be on an unloading list which is okay, ie. still allocated
596 // for a little while.
597 for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
598 if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
599 return true;
600 }
601 }
602 return false;
603 }
605 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
606 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
607 if (loader_data == data) {
608 return true;
609 }
610 }
612 return false;
613 }
614 #endif // PRODUCT
617 // Move class loader data from main list to the unloaded list for unloading
618 // and deallocation later.
619 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
620 ClassLoaderData* data = _head;
621 ClassLoaderData* prev = NULL;
622 bool seen_dead_loader = false;
623 // mark metadata seen on the stack and code cache so we can delete
624 // unneeded entries.
625 bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
626 MetadataOnStackMark md_on_stack;
627 while (data != NULL) {
628 if (data->keep_alive() || data->is_alive(is_alive_closure)) {
629 if (has_redefined_a_class) {
630 data->classes_do(InstanceKlass::purge_previous_versions);
631 }
632 data->free_deallocate_list();
633 prev = data;
634 data = data->next();
635 continue;
636 }
637 seen_dead_loader = true;
638 ClassLoaderData* dead = data;
639 dead->unload();
640 data = data->next();
641 // Remove from loader list.
642 if (prev != NULL) {
643 prev->set_next(data);
644 } else {
645 assert(dead == _head, "sanity check");
646 _head = data;
647 }
648 dead->set_next(_unloading);
649 _unloading = dead;
650 }
651 return seen_dead_loader;
652 }
654 void ClassLoaderDataGraph::purge() {
655 ClassLoaderData* list = _unloading;
656 _unloading = NULL;
657 ClassLoaderData* next = list;
658 while (next != NULL) {
659 ClassLoaderData* purge_me = next;
660 next = purge_me->next();
661 delete purge_me;
662 }
663 }
665 // CDS support
667 // Global metaspaces for writing information to the shared archive. When
668 // application CDS is supported, we may need one per metaspace, so this
669 // sort of looks like it.
670 Metaspace* ClassLoaderData::_ro_metaspace = NULL;
671 Metaspace* ClassLoaderData::_rw_metaspace = NULL;
672 static bool _shared_metaspaces_initialized = false;
674 // Initialize shared metaspaces (change to call from somewhere not lazily)
675 void ClassLoaderData::initialize_shared_metaspaces() {
676 assert(DumpSharedSpaces, "only use this for dumping shared spaces");
677 assert(this == ClassLoaderData::the_null_class_loader_data(),
678 "only supported for null loader data for now");
679 assert (!_shared_metaspaces_initialized, "only initialize once");
680 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
681 _ro_metaspace = new Metaspace(_metaspace_lock, SharedReadOnlySize/wordSize);
682 _rw_metaspace = new Metaspace(_metaspace_lock, SharedReadWriteSize/wordSize);
683 _shared_metaspaces_initialized = true;
684 }
686 Metaspace* ClassLoaderData::ro_metaspace() {
687 assert(_ro_metaspace != NULL, "should already be initialized");
688 return _ro_metaspace;
689 }
691 Metaspace* ClassLoaderData::rw_metaspace() {
692 assert(_rw_metaspace != NULL, "should already be initialized");
693 return _rw_metaspace;
694 }
697 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
698 _data = ClassLoaderDataGraph::_head;
699 }
701 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
703 #ifndef PRODUCT
704 // callable from debugger
705 extern "C" int print_loader_data_graph() {
706 ClassLoaderDataGraph::dump_on(tty);
707 return 0;
708 }
710 void ClassLoaderDataGraph::verify() {
711 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
712 data->verify();
713 }
714 }
716 void ClassLoaderDataGraph::dump_on(outputStream * const out) {
717 for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
718 data->dump(out);
719 }
720 MetaspaceAux::dump(out);
721 }
723 void ClassLoaderData::print_value_on(outputStream* out) const {
724 if (class_loader() == NULL) {
725 out->print_cr("NULL class_loader");
726 } else {
727 out->print("class loader "PTR_FORMAT, this);
728 class_loader()->print_value_on(out);
729 }
730 }
731 #endif // PRODUCT