CLD claiming v2
128 // name. Thus CLD's _name_and_id field should never have a null value.
129 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(class_loader());
130 const char* cl_instance_name_and_id =
131 (cl_name_and_id == NULL) ? _class_loader_klass->external_name() :
132 java_lang_String::as_utf8_string(cl_name_and_id);
133 assert(cl_instance_name_and_id != NULL && cl_instance_name_and_id[0] != '\0', "class loader has no name and id");
134 // Can't throw InternalError and SymbolTable doesn't throw OOM anymore.
135 _name_and_id = SymbolTable::new_symbol(cl_instance_name_and_id, CATCH);
136 }
137
138 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_unsafe_anonymous) :
139 _metaspace(NULL),
140 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true,
141 Monitor::_safepoint_check_never)),
142 _unloading(false), _is_unsafe_anonymous(is_unsafe_anonymous),
143 _modified_oops(true), _accumulated_modified_oops(false),
144 // An unsafe anonymous class loader data doesn't have anything to keep
145 // it from being unloaded during parsing of the unsafe anonymous class.
146 // The null-class-loader should always be kept alive.
147 _keep_alive((is_unsafe_anonymous || h_class_loader.is_null()) ? 1 : 0),
148 _claim_value(0),
149 _handles(),
150 _klasses(NULL), _packages(NULL), _modules(NULL), _unnamed_module(NULL), _dictionary(NULL),
151 _jmethod_ids(NULL),
152 _deallocate_list(NULL),
153 _next(NULL),
154 _class_loader_klass(NULL), _name(NULL), _name_and_id(NULL) {
155
156 if (!h_class_loader.is_null()) {
157 _class_loader = _handles.add(h_class_loader());
158 _class_loader_klass = h_class_loader->klass();
159 }
160
161 if (!is_unsafe_anonymous) {
162 // The holder is initialized later for unsafe anonymous classes, and before calling anything
163 // that call class_loader().
164 initialize_holder(h_class_loader);
165
166 // A ClassLoaderData created solely for an unsafe anonymous class should never have a
167 // ModuleEntryTable or PackageEntryTable created for it. The defining package
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128 // name. Thus CLD's _name_and_id field should never have a null value.
129 oop cl_name_and_id = java_lang_ClassLoader::nameAndId(class_loader());
130 const char* cl_instance_name_and_id =
131 (cl_name_and_id == NULL) ? _class_loader_klass->external_name() :
132 java_lang_String::as_utf8_string(cl_name_and_id);
133 assert(cl_instance_name_and_id != NULL && cl_instance_name_and_id[0] != '\0', "class loader has no name and id");
134 // Can't throw InternalError and SymbolTable doesn't throw OOM anymore.
135 _name_and_id = SymbolTable::new_symbol(cl_instance_name_and_id, CATCH);
136 }
137
138 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_unsafe_anonymous) :
139 _metaspace(NULL),
140 _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true,
141 Monitor::_safepoint_check_never)),
142 _unloading(false), _is_unsafe_anonymous(is_unsafe_anonymous),
143 _modified_oops(true), _accumulated_modified_oops(false),
144 // An unsafe anonymous class loader data doesn't have anything to keep
145 // it from being unloaded during parsing of the unsafe anonymous class.
146 // The null-class-loader should always be kept alive.
147 _keep_alive((is_unsafe_anonymous || h_class_loader.is_null()) ? 1 : 0),
148 _claim(0),
149 _handles(),
150 _klasses(NULL), _packages(NULL), _modules(NULL), _unnamed_module(NULL), _dictionary(NULL),
151 _jmethod_ids(NULL),
152 _deallocate_list(NULL),
153 _next(NULL),
154 _class_loader_klass(NULL), _name(NULL), _name_and_id(NULL) {
155
156 if (!h_class_loader.is_null()) {
157 _class_loader = _handles.add(h_class_loader());
158 _class_loader_klass = h_class_loader->klass();
159 }
160
161 if (!is_unsafe_anonymous) {
162 // The holder is initialized later for unsafe anonymous classes, and before calling anything
163 // that call class_loader().
164 initialize_holder(h_class_loader);
165
166 // A ClassLoaderData created solely for an unsafe anonymous class should never have a
167 // ModuleEntryTable or PackageEntryTable created for it. The defining package
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256
257 bool ClassLoaderData::ChunkedHandleList::contains(oop p) {
258 VerifyContainsOopClosure cl(p);
259 oops_do(&cl);
260 return cl.found();
261 }
262
263 #ifndef PRODUCT
264 bool ClassLoaderData::ChunkedHandleList::owner_of(oop* oop_handle) {
265 Chunk* chunk = _head;
266 while (chunk != NULL) {
267 if (&(chunk->_data[0]) <= oop_handle && oop_handle < &(chunk->_data[chunk->_size])) {
268 return true;
269 }
270 chunk = chunk->_next;
271 }
272 return false;
273 }
274 #endif // PRODUCT
275
276 bool ClassLoaderData::claim(int claim_value) {
277 for (;;) {
278 int old_claim = Atomic::load(&_claim_value);
279 if ((old_claim & claim_value) == claim_value) {
280 return false;
281 }
282 int new_claim = old_claim | claim_value;
283 if (Atomic::cmpxchg(new_claim, &_claim_value, old_claim) == old_claim) {
284 return true;
285 }
286 }
287 }
288
289 // Unsafe anonymous classes have their own ClassLoaderData that is marked to keep alive
290 // while the class is being parsed, and if the class appears on the module fixup list.
291 // Due to the uniqueness that no other class shares the unsafe anonymous class' name or
292 // ClassLoaderData, no other non-GC thread has knowledge of the unsafe anonymous class while
293 // it is being defined, therefore _keep_alive is not volatile or atomic.
294 void ClassLoaderData::inc_keep_alive() {
295 if (is_unsafe_anonymous()) {
296 assert(_keep_alive >= 0, "Invalid keep alive increment count");
297 _keep_alive++;
298 }
299 }
300
301 void ClassLoaderData::dec_keep_alive() {
302 if (is_unsafe_anonymous()) {
303 assert(_keep_alive > 0, "Invalid keep alive decrement count");
304 _keep_alive--;
305 }
306 }
307
308 void ClassLoaderData::oops_do(OopClosure* f, int claim_value, bool clear_mod_oops) {
309 if (claim_value != ClassLoaderData::_claim_value_none && !claim(claim_value)) {
310 return;
311 }
312
313 // Only clear modified_oops after the ClassLoaderData is claimed.
314 if (clear_mod_oops) {
315 clear_modified_oops();
316 }
317
318 _handles.oops_do(f);
319 }
320
321 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
322 // Lock-free access requires load_acquire
323 for (Klass* k = OrderAccess::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
324 klass_closure->do_klass(k);
325 assert(k != k->next_link(), "no loops!");
326 }
327 }
328
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256
257 bool ClassLoaderData::ChunkedHandleList::contains(oop p) {
258 VerifyContainsOopClosure cl(p);
259 oops_do(&cl);
260 return cl.found();
261 }
262
263 #ifndef PRODUCT
264 bool ClassLoaderData::ChunkedHandleList::owner_of(oop* oop_handle) {
265 Chunk* chunk = _head;
266 while (chunk != NULL) {
267 if (&(chunk->_data[0]) <= oop_handle && oop_handle < &(chunk->_data[chunk->_size])) {
268 return true;
269 }
270 chunk = chunk->_next;
271 }
272 return false;
273 }
274 #endif // PRODUCT
275
276 bool ClassLoaderData::try_claim(int claim) {
277 for (;;) {
278 int old_claim = Atomic::load(&_claim);
279 if ((old_claim & claim) == claim) {
280 return false;
281 }
282 int new_claim = old_claim | claim;
283 if (Atomic::cmpxchg(new_claim, &_claim, old_claim) == old_claim) {
284 return true;
285 }
286 }
287 }
288
289 // Unsafe anonymous classes have their own ClassLoaderData that is marked to keep alive
290 // while the class is being parsed, and if the class appears on the module fixup list.
291 // Due to the uniqueness that no other class shares the unsafe anonymous class' name or
292 // ClassLoaderData, no other non-GC thread has knowledge of the unsafe anonymous class while
293 // it is being defined, therefore _keep_alive is not volatile or atomic.
294 void ClassLoaderData::inc_keep_alive() {
295 if (is_unsafe_anonymous()) {
296 assert(_keep_alive >= 0, "Invalid keep alive increment count");
297 _keep_alive++;
298 }
299 }
300
301 void ClassLoaderData::dec_keep_alive() {
302 if (is_unsafe_anonymous()) {
303 assert(_keep_alive > 0, "Invalid keep alive decrement count");
304 _keep_alive--;
305 }
306 }
307
308 void ClassLoaderData::oops_do(OopClosure* f, int claim_value, bool clear_mod_oops) {
309 if (claim_value != ClassLoaderData::_claim_none && !try_claim(claim_value)) {
310 return;
311 }
312
313 // Only clear modified_oops after the ClassLoaderData is claimed.
314 if (clear_mod_oops) {
315 clear_modified_oops();
316 }
317
318 _handles.oops_do(f);
319 }
320
321 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
322 // Lock-free access requires load_acquire
323 for (Klass* k = OrderAccess::load_acquire(&_klasses); k != NULL; k = k->next_link()) {
324 klass_closure->do_klass(k);
325 assert(k != k->next_link(), "no loops!");
326 }
327 }
328
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433 LogTarget(Trace, class, loader, data) lt;
434 if (lt.is_enabled()) {
435 ResourceMark rm;
436 LogStream ls(lt);
437 ls.print("adding dependency from ");
438 print_value_on(&ls);
439 ls.print(" to ");
440 to_cld->print_value_on(&ls);
441 ls.cr();
442 }
443 Handle dependency(Thread::current(), to);
444 add_handle(dependency);
445 // Added a potentially young gen oop to the ClassLoaderData
446 record_modified_oops();
447 }
448 }
449
450
451 void ClassLoaderDataGraph::clear_claimed_marks() {
452 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
453 cld->clear_claimed();
454 }
455 }
456
457 void ClassLoaderData::add_class(Klass* k, bool publicize /* true */) {
458 {
459 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
460 Klass* old_value = _klasses;
461 k->set_next_link(old_value);
462 // Link the new item into the list, making sure the linked class is stable
463 // since the list can be walked without a lock
464 OrderAccess::release_store(&_klasses, k);
465 if (k->is_array_klass()) {
466 ClassLoaderDataGraph::inc_array_classes(1);
467 } else {
468 ClassLoaderDataGraph::inc_instance_classes(1);
469 }
470 }
471
472 if (publicize) {
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433 LogTarget(Trace, class, loader, data) lt;
434 if (lt.is_enabled()) {
435 ResourceMark rm;
436 LogStream ls(lt);
437 ls.print("adding dependency from ");
438 print_value_on(&ls);
439 ls.print(" to ");
440 to_cld->print_value_on(&ls);
441 ls.cr();
442 }
443 Handle dependency(Thread::current(), to);
444 add_handle(dependency);
445 // Added a potentially young gen oop to the ClassLoaderData
446 record_modified_oops();
447 }
448 }
449
450
451 void ClassLoaderDataGraph::clear_claimed_marks() {
452 for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
453 cld->clear_claim();
454 }
455 }
456
457 void ClassLoaderData::add_class(Klass* k, bool publicize /* true */) {
458 {
459 MutexLockerEx ml(metaspace_lock(), Mutex::_no_safepoint_check_flag);
460 Klass* old_value = _klasses;
461 k->set_next_link(old_value);
462 // Link the new item into the list, making sure the linked class is stable
463 // since the list can be walked without a lock
464 OrderAccess::release_store(&_klasses, k);
465 if (k->is_array_klass()) {
466 ClassLoaderDataGraph::inc_array_classes(1);
467 } else {
468 ClassLoaderDataGraph::inc_instance_classes(1);
469 }
470 }
471
472 if (publicize) {
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