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 }