| /* |
| * Copyright (c) 2012, 2016, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| * |
| */ |
| |
| #ifndef SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP |
| #define SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP |
| |
| #include "memory/allocation.hpp" |
| #include "memory/memRegion.hpp" |
| #include "memory/metaspace.hpp" |
| #include "memory/metaspaceCounters.hpp" |
| #include "runtime/mutex.hpp" |
| #include "utilities/growableArray.hpp" |
| #include "utilities/macros.hpp" |
| #if INCLUDE_TRACE |
| #include "utilities/ticks.hpp" |
| #endif |
| |
| // |
| // A class loader represents a linkset. Conceptually, a linkset identifies |
| // the complete transitive closure of resolved links that a dynamic linker can |
| // produce. |
| // |
| // A ClassLoaderData also encapsulates the allocation space, called a metaspace, |
| // used by the dynamic linker to allocate the runtime representation of all |
| // the types it defines. |
| // |
| // ClassLoaderData are stored in the runtime representation of classes and the |
| // system dictionary, are roots of garbage collection, and provides iterators |
| // for root tracing and other GC operations. |
| |
| class ClassLoaderData; |
| class JNIMethodBlock; |
| class JNIHandleBlock; |
| class Metadebug; |
| class ModuleEntry; |
| class PackageEntry; |
| class ModuleEntryTable; |
| class PackageEntryTable; |
| |
| // GC root for walking class loader data created |
| |
| class ClassLoaderDataGraph : public AllStatic { |
| friend class ClassLoaderData; |
| friend class ClassLoaderDataGraphMetaspaceIterator; |
| friend class ClassLoaderDataGraphKlassIteratorAtomic; |
| friend class VMStructs; |
| private: |
| // All CLDs (except the null CLD) can be reached by walking _head->_next->... |
| static ClassLoaderData* _head; |
| static ClassLoaderData* _unloading; |
| // CMS support. |
| static ClassLoaderData* _saved_head; |
| static ClassLoaderData* _saved_unloading; |
| static bool _should_purge; |
| // OOM has been seen in metaspace allocation. Used to prevent some |
| // allocations until class unloading |
| static bool _metaspace_oom; |
| |
| static ClassLoaderData* add(Handle class_loader, bool anonymous, TRAPS); |
| static void post_class_unload_events(void); |
| public: |
| static ClassLoaderData* find_or_create(Handle class_loader, TRAPS); |
| static void purge(); |
| static void clear_claimed_marks(); |
| // oops do |
| static void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim); |
| static void keep_alive_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim); |
| static void always_strong_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim); |
| // cld do |
| static void cld_do(CLDClosure* cl); |
| static void roots_cld_do(CLDClosure* strong, CLDClosure* weak); |
| static void keep_alive_cld_do(CLDClosure* cl); |
| static void always_strong_cld_do(CLDClosure* cl); |
| // klass do |
| static void classes_do(KlassClosure* klass_closure); |
| static void classes_do(void f(Klass* const)); |
| static void methods_do(void f(Method*)); |
| static void modules_do(void f(ModuleEntry*)); |
| static void modules_unloading_do(void f(ModuleEntry*)); |
| static void packages_do(void f(PackageEntry*)); |
| static void packages_unloading_do(void f(PackageEntry*)); |
| static void loaded_classes_do(KlassClosure* klass_closure); |
| static void classes_unloading_do(void f(Klass* const)); |
| static bool do_unloading(BoolObjectClosure* is_alive, bool clean_previous_versions); |
| |
| // CMS support. |
| static void remember_new_clds(bool remember) { _saved_head = (remember ? _head : NULL); } |
| static GrowableArray<ClassLoaderData*>* new_clds(); |
| |
| static void set_should_purge(bool b) { _should_purge = b; } |
| static void purge_if_needed() { |
| // Only purge the CLDG for CMS if concurrent sweep is complete. |
| if (_should_purge) { |
| purge(); |
| // reset for next time. |
| set_should_purge(false); |
| } |
| } |
| |
| static bool has_metaspace_oom() { return _metaspace_oom; } |
| static void set_metaspace_oom(bool value) { _metaspace_oom = value; } |
| |
| static void dump_on(outputStream * const out) PRODUCT_RETURN; |
| static void dump() { dump_on(tty); } |
| static void verify(); |
| static void log_creation(Handle loader, ClassLoaderData* cld, TRAPS); |
| |
| static bool unload_list_contains(const void* x); |
| #ifndef PRODUCT |
| static bool contains_loader_data(ClassLoaderData* loader_data); |
| #endif |
| |
| #if INCLUDE_TRACE |
| private: |
| static Ticks _class_unload_time; |
| static void class_unload_event(Klass* const k); |
| #endif |
| }; |
| |
| // ClassLoaderData class |
| |
| class ClassLoaderData : public CHeapObj<mtClass> { |
| friend class VMStructs; |
| private: |
| class Dependencies VALUE_OBJ_CLASS_SPEC { |
| objArrayOop _list_head; |
| void locked_add(objArrayHandle last, |
| objArrayHandle new_dependency, |
| Thread* THREAD); |
| public: |
| Dependencies() : _list_head(NULL) {} |
| Dependencies(TRAPS) : _list_head(NULL) { |
| init(CHECK); |
| } |
| void add(Handle dependency, TRAPS); |
| void init(TRAPS); |
| void oops_do(OopClosure* f); |
| }; |
| |
| friend class ClassLoaderDataGraph; |
| friend class ClassLoaderDataGraphKlassIteratorAtomic; |
| friend class ClassLoaderDataGraphMetaspaceIterator; |
| friend class MetaDataFactory; |
| friend class Method; |
| |
| static ClassLoaderData * _the_null_class_loader_data; |
| |
| oop _class_loader; // oop used to uniquely identify a class loader |
| // class loader or a canonical class path |
| Dependencies _dependencies; // holds dependencies from this class loader |
| // data to others. |
| |
| Metaspace * volatile _metaspace; // Meta-space where meta-data defined by the |
| // classes in the class loader are allocated. |
| Mutex* _metaspace_lock; // Locks the metaspace for allocations and setup. |
| bool _unloading; // true if this class loader goes away |
| bool _is_anonymous; // if this CLD is for an anonymous class |
| int _keep_alive; // if this CLD is kept alive without a keep_alive_object(). |
| // Currently used solely for anonymous classes. |
| // _keep_alive does not need to be volatile or |
| // atomic since there is one unique CLD per anonymous class. |
| volatile int _claimed; // true if claimed, for example during GC traces. |
| // To avoid applying oop closure more than once. |
| // Has to be an int because we cas it. |
| JNIHandleBlock* _handles; // Handles to constant pool arrays, Modules, etc, which |
| // have the same life cycle of the corresponding ClassLoader. |
| |
| Klass* volatile _klasses; // The classes defined by the class loader. |
| PackageEntryTable* volatile _packages; // The packages defined by the class loader. |
| ModuleEntryTable* volatile _modules; // The modules defined by the class loader. |
| |
| // These method IDs are created for the class loader and set to NULL when the |
| // class loader is unloaded. They are rarely freed, only for redefine classes |
| // and if they lose a data race in InstanceKlass. |
| JNIMethodBlock* _jmethod_ids; |
| |
| // Metadata to be deallocated when it's safe at class unloading, when |
| // this class loader isn't unloaded itself. |
| GrowableArray<Metadata*>* _deallocate_list; |
| |
| // Support for walking class loader data objects |
| ClassLoaderData* _next; /// Next loader_datas created |
| |
| // CDS |
| int _shared_class_loader_id; |
| |
| // ReadOnly and ReadWrite metaspaces (static because only on the null |
| // class loader for now). |
| static Metaspace* _ro_metaspace; |
| static Metaspace* _rw_metaspace; |
| |
| void set_next(ClassLoaderData* next) { _next = next; } |
| ClassLoaderData* next() const { return _next; } |
| |
| ClassLoaderData(Handle h_class_loader, bool is_anonymous, Dependencies dependencies); |
| ~ClassLoaderData(); |
| |
| JNIHandleBlock* handles() const; |
| void set_handles(JNIHandleBlock* handles); |
| |
| // GC interface. |
| void clear_claimed() { _claimed = 0; } |
| bool claimed() const { return _claimed == 1; } |
| bool claim(); |
| |
| void unload(); |
| bool keep_alive() const { return _keep_alive > 0; } |
| void classes_do(void f(Klass*)); |
| void loaded_classes_do(KlassClosure* klass_closure); |
| void classes_do(void f(InstanceKlass*)); |
| void methods_do(void f(Method*)); |
| void modules_do(void f(ModuleEntry*)); |
| void packages_do(void f(PackageEntry*)); |
| |
| // Deallocate free list during class unloading. |
| void free_deallocate_list(); |
| |
| // Allocate out of this class loader data |
| MetaWord* allocate(size_t size); |
| |
| public: |
| |
| bool is_alive(BoolObjectClosure* is_alive_closure) const; |
| |
| // Accessors |
| Metaspace* metaspace_or_null() const { return _metaspace; } |
| |
| static ClassLoaderData* the_null_class_loader_data() { |
| return _the_null_class_loader_data; |
| } |
| |
| Mutex* metaspace_lock() const { return _metaspace_lock; } |
| |
| bool is_anonymous() const { return _is_anonymous; } |
| |
| static void init_null_class_loader_data() { |
| assert(_the_null_class_loader_data == NULL, "cannot initialize twice"); |
| assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice"); |
| |
| // We explicitly initialize the Dependencies object at a later phase in the initialization |
| _the_null_class_loader_data = new ClassLoaderData((oop)NULL, false, Dependencies()); |
| ClassLoaderDataGraph::_head = _the_null_class_loader_data; |
| assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be"); |
| if (DumpSharedSpaces) { |
| _the_null_class_loader_data->initialize_shared_metaspaces(); |
| } |
| } |
| |
| bool is_the_null_class_loader_data() const { |
| return this == _the_null_class_loader_data; |
| } |
| bool is_platform_class_loader_data() const; |
| |
| // The Metaspace is created lazily so may be NULL. This |
| // method will allocate a Metaspace if needed. |
| Metaspace* metaspace_non_null(); |
| |
| oop class_loader() const { return _class_loader; } |
| |
| // The object the GC is using to keep this ClassLoaderData alive. |
| oop keep_alive_object() const; |
| |
| // Returns true if this class loader data is for a loader going away. |
| bool is_unloading() const { |
| assert(!(is_the_null_class_loader_data() && _unloading), "The null class loader can never be unloaded"); |
| return _unloading; |
| } |
| |
| void inc_keep_alive(); |
| void dec_keep_alive(); |
| |
| inline unsigned int identity_hash() const; |
| |
| // Used when tracing from klasses. |
| void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim); |
| |
| void classes_do(KlassClosure* klass_closure); |
| |
| JNIMethodBlock* jmethod_ids() const { return _jmethod_ids; } |
| void set_jmethod_ids(JNIMethodBlock* new_block) { _jmethod_ids = new_block; } |
| |
| void print_value() { print_value_on(tty); } |
| void print_value_on(outputStream* out) const; |
| void dump(outputStream * const out) PRODUCT_RETURN; |
| void verify(); |
| const char* loader_name(); |
| |
| jobject add_handle(Handle h); |
| void remove_handle(jobject h); |
| void add_class(Klass* k, bool publicize = true); |
| void remove_class(Klass* k); |
| bool contains_klass(Klass* k); |
| void record_dependency(const Klass* to, TRAPS); |
| void init_dependencies(TRAPS); |
| PackageEntryTable* packages(); |
| bool packages_defined() { return (_packages != NULL); } |
| ModuleEntryTable* modules(); |
| bool modules_defined() { return (_modules != NULL); } |
| |
| void add_to_deallocate_list(Metadata* m); |
| |
| static ClassLoaderData* class_loader_data(oop loader); |
| static ClassLoaderData* class_loader_data_or_null(oop loader); |
| static ClassLoaderData* anonymous_class_loader_data(oop loader, TRAPS); |
| static void print_loader(ClassLoaderData *loader_data, outputStream *out); |
| |
| // CDS support |
| Metaspace* ro_metaspace(); |
| Metaspace* rw_metaspace(); |
| void initialize_shared_metaspaces(); |
| |
| int shared_class_loader_id() const { |
| return _shared_class_loader_id; |
| } |
| void set_shared_class_loader_id(int id) { |
| assert(id >= 0, "sanity"); |
| assert(_shared_class_loader_id <0, "cannot be assigned more than once"); |
| _shared_class_loader_id = id; |
| } |
| }; |
| |
| // An iterator that distributes Klasses to parallel worker threads. |
| class ClassLoaderDataGraphKlassIteratorAtomic : public StackObj { |
| Klass* volatile _next_klass; |
| public: |
| ClassLoaderDataGraphKlassIteratorAtomic(); |
| Klass* next_klass(); |
| private: |
| static Klass* next_klass_in_cldg(Klass* klass); |
| }; |
| |
| class ClassLoaderDataGraphMetaspaceIterator : public StackObj { |
| ClassLoaderData* _data; |
| public: |
| ClassLoaderDataGraphMetaspaceIterator(); |
| ~ClassLoaderDataGraphMetaspaceIterator(); |
| bool repeat() { return _data != NULL; } |
| Metaspace* get_next() { |
| assert(_data != NULL, "Should not be NULL in call to the iterator"); |
| Metaspace* result = _data->metaspace_or_null(); |
| _data = _data->next(); |
| // This result might be NULL for class loaders without metaspace |
| // yet. It would be nice to return only non-null results but |
| // there is no guarantee that there will be a non-null result |
| // down the list so the caller is going to have to check. |
| return result; |
| } |
| }; |
| #endif // SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP |