jdk8-mips64-public/hotspot: src/share/vm/classfile/classLoaderData.cpp@2c6ef90f030a (annotated)

src/share/vm/classfile/classLoaderData.cpp@2c6ef90f030a (annotated)

src/share/vm/classfile/classLoaderData.cpp

Mon, 07 Jul 2014 10:12:40 +0200

author: stefank
date: Mon, 07 Jul 2014 10:12:40 +0200
changeset 6992: 2c6ef90f030a
parent 6974: 556a06aec3fa
child 7333: b12a2a9b05ca
permissions: -rw-r--r--

8049421: G1 Class Unloading after completing a concurrent mark cycle
Reviewed-by: tschatzl, ehelin, brutisso, coleenp, roland, iveresov
Contributed-by: stefan.karlsson@oracle.com, mikael.gerdin@oracle.com

 /*
  * Copyright (c) 2012, 2014, 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.
  *
  */
 // A ClassLoaderData identifies the full set of class types that a class
 // loader's name resolution strategy produces for a given configuration of the
 // class loader.
 // Class types in the ClassLoaderData may be defined by from class file binaries
 // provided by the class loader, or from other class loader it interacts with
 // according to its name resolution strategy.
 //
 // Class loaders that implement a deterministic name resolution strategy
 // (including with respect to their delegation behavior), such as the boot, the
 // extension, and the system loaders of the JDK's built-in class loader
 // hierarchy, always produce the same linkset for a given configuration.
 //
 // ClassLoaderData carries information related to a linkset (e.g.,
 // metaspace holding its klass definitions).
 // The System Dictionary and related data structures (e.g., placeholder table,
 // loader constraints table) as well as the runtime representation of classes
 // only reference ClassLoaderData.
 //
 // Instances of java.lang.ClassLoader holds a pointer to a ClassLoaderData that
 // that represent the loader's "linking domain" in the JVM.
 //
 // The bootstrap loader (represented by NULL) also has a ClassLoaderData,
 // the singleton class the_null_class_loader_data().
 #include "precompiled.hpp"
 #include "classfile/classLoaderData.hpp"
 #include "classfile/classLoaderData.inline.hpp"
 #include "classfile/javaClasses.hpp"
 #include "classfile/metadataOnStackMark.hpp"
 #include "classfile/systemDictionary.hpp"
 #include "code/codeCache.hpp"
 #include "memory/gcLocker.hpp"
 #include "memory/metadataFactory.hpp"
 #include "memory/metaspaceShared.hpp"
 #include "memory/oopFactory.hpp"
 #include "runtime/jniHandles.hpp"
 #include "runtime/mutex.hpp"
 #include "runtime/safepoint.hpp"
 #include "runtime/synchronizer.hpp"
 #include "utilities/growableArray.hpp"
 #include "utilities/macros.hpp"
 #include "utilities/ostream.hpp"
 #if INCLUDE_TRACE
  #include "trace/tracing.hpp"
 #endif
 ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
 ClassLoaderData::ClassLoaderData(Handle h_class_loader, bool is_anonymous, Dependencies dependencies) :
   _class_loader(h_class_loader()),
   _is_anonymous(is_anonymous),
   // An anonymous class loader data doesn't have anything to keep
   // it from being unloaded during parsing of the anonymous class.
   // The null-class-loader should always be kept alive.
   _keep_alive(is_anonymous || h_class_loader.is_null()),
   _metaspace(NULL), _unloading(false), _klasses(NULL),
   _claimed(0), _jmethod_ids(NULL), _handles(NULL), _deallocate_list(NULL),
   _next(NULL), _dependencies(dependencies),
   _metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
     // empty
 }
 void ClassLoaderData::init_dependencies(TRAPS) {
   assert(!Universe::is_fully_initialized(), "should only be called when initializing");
   assert(is_the_null_class_loader_data(), "should only call this for the null class loader");
   _dependencies.init(CHECK);
 }
 void ClassLoaderData::Dependencies::init(TRAPS) {
   // Create empty dependencies array to add to. CMS requires this to be
   // an oop so that it can track additions via card marks.  We think.
   _list_head = oopFactory::new_objectArray(2, CHECK);
 }
 bool ClassLoaderData::claim() {
   if (_claimed == 1) {
     return false;
   }
   return (int) Atomic::cmpxchg(1, &_claimed, 0) == 0;
 }
 void ClassLoaderData::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
   if (must_claim && !claim()) {
     return;
   }
   f->do_oop(&_class_loader);
   _dependencies.oops_do(f);
   _handles->oops_do(f);
   if (klass_closure != NULL) {
     classes_do(klass_closure);
   }
 }
 void ClassLoaderData::Dependencies::oops_do(OopClosure* f) {
   f->do_oop((oop*)&_list_head);
 }
 void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     klass_closure->do_klass(k);
     assert(k != k->next_link(), "no loops!");
   }
 }
 void ClassLoaderData::classes_do(void f(Klass * const)) {
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     f(k);
   }
 }
 void ClassLoaderData::loaded_classes_do(KlassClosure* klass_closure) {
   // Lock to avoid classes being modified/added/removed during iteration
   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     // Do not filter ArrayKlass oops here...
     if (k->oop_is_array() || (k->oop_is_instance() && InstanceKlass::cast(k)->is_loaded())) {
       klass_closure->do_klass(k);
     }
   }
 }
 void ClassLoaderData::classes_do(void f(InstanceKlass*)) {
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     if (k->oop_is_instance()) {
       f(InstanceKlass::cast(k));
     }
     assert(k != k->next_link(), "no loops!");
   }
 }
 void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
   ClassLoaderData * const from_cld = this;
   ClassLoaderData * const to_cld = k->class_loader_data();
   // Dependency to the null class loader data doesn't need to be recorded
   // because the null class loader data never goes away.
   if (to_cld->is_the_null_class_loader_data()) {
     return;
   }
   oop to;
   if (to_cld->is_anonymous()) {
     // Anonymous class dependencies are through the mirror.
     to = k->java_mirror();
   } else {
     to = to_cld->class_loader();
     // If from_cld is anonymous, even if it's class_loader is a parent of 'to'
     // we still have to add it.  The class_loader won't keep from_cld alive.
     if (!from_cld->is_anonymous()) {
       // Check that this dependency isn't from the same or parent class_loader
       oop from = from_cld->class_loader();
       oop curr = from;
       while (curr != NULL) {
         if (curr == to) {
           return; // this class loader is in the parent list, no need to add it.
         }
         curr = java_lang_ClassLoader::parent(curr);
       }
     }
   }
   // It's a dependency we won't find through GC, add it. This is relatively rare
   // Must handle over GC point.
   Handle dependency(THREAD, to);
   from_cld->_dependencies.add(dependency, CHECK);
 }
 void ClassLoaderData::Dependencies::add(Handle dependency, TRAPS) {
   // Check first if this dependency is already in the list.
   // Save a pointer to the last to add to under the lock.
   objArrayOop ok = _list_head;
   objArrayOop last = NULL;
   while (ok != NULL) {
     last = ok;
     if (ok->obj_at(0) == dependency()) {
       // Don't need to add it
       return;
     }
     ok = (objArrayOop)ok->obj_at(1);
   }
   // Must handle over GC points
   assert (last != NULL, "dependencies should be initialized");
   objArrayHandle last_handle(THREAD, last);
   // Create a new dependency node with fields for (class_loader or mirror, next)
   objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
   deps->obj_at_put(0, dependency());
   // Must handle over GC points
   objArrayHandle new_dependency(THREAD, deps);
   // Add the dependency under lock
   locked_add(last_handle, new_dependency, THREAD);
 }
 void ClassLoaderData::Dependencies::locked_add(objArrayHandle last_handle,
                                                objArrayHandle new_dependency,
                                                Thread* THREAD) {
   // Have to lock and put the new dependency on the end of the dependency
   // array so the card mark for CMS sees that this dependency is new.
   // Can probably do this lock free with some effort.
   ObjectLocker ol(Handle(THREAD, _list_head), THREAD);
   oop loader_or_mirror = new_dependency->obj_at(0);
   // Since the dependencies are only added, add to the end.
   objArrayOop end = last_handle();
   objArrayOop last = NULL;
   while (end != NULL) {
     last = end;
     // check again if another thread added it to the end.
     if (end->obj_at(0) == loader_or_mirror) {
       // Don't need to add it
       return;
     }
     end = (objArrayOop)end->obj_at(1);
   }
   assert (last != NULL, "dependencies should be initialized");
   // fill in the first element with the oop in new_dependency.
   if (last->obj_at(0) == NULL) {
     last->obj_at_put(0, new_dependency->obj_at(0));
   } else {
     last->obj_at_put(1, new_dependency());
   }
 }
 void ClassLoaderDataGraph::clear_claimed_marks() {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     cld->clear_claimed();
   }
 }
 void ClassLoaderData::add_class(Klass* k) {
   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
   Klass* old_value = _klasses;
   k->set_next_link(old_value);
   // link the new item into the list
   _klasses = k;
   if (TraceClassLoaderData && Verbose && k->class_loader_data() != NULL) {
     ResourceMark rm;
     tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
                   PTR_FORMAT " loader: " PTR_FORMAT " %s",
                   p2i(k),
                   k->external_name(),
                   p2i(k->class_loader_data()),
                   p2i((void *)k->class_loader()),
                   loader_name());
   }
 }
 // This is called by InstanceKlass::deallocate_contents() to remove the
 // scratch_class for redefine classes.  We need a lock because there it may not
 // be called at a safepoint if there's an error.
 void ClassLoaderData::remove_class(Klass* scratch_class) {
   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
   Klass* prev = NULL;
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     if (k == scratch_class) {
       if (prev == NULL) {
         _klasses = k->next_link();
       } else {
         Klass* next = k->next_link();
         prev->set_next_link(next);
       }
       return;
     }
     prev = k;
     assert(k != k->next_link(), "no loops!");
   }
   ShouldNotReachHere();   // should have found this class!!
 }
 void ClassLoaderData::unload() {
   _unloading = true;
   // Tell serviceability tools these classes are unloading
   classes_do(InstanceKlass::notify_unload_class);
   if (TraceClassLoaderData) {
     ResourceMark rm;
     tty->print("[ClassLoaderData: unload loader data " INTPTR_FORMAT, p2i(this));
     tty->print(" for instance " INTPTR_FORMAT " of %s", p2i((void *)class_loader()),
                loader_name());
     if (is_anonymous()) {
       tty->print(" for anonymous class  " INTPTR_FORMAT " ", p2i(_klasses));
     }
     tty->print_cr("]");
   }
 }
 #ifdef ASSERT
 class AllAliveClosure : public OopClosure {
   BoolObjectClosure* _is_alive_closure;
   bool _found_dead;
  public:
   AllAliveClosure(BoolObjectClosure* is_alive_closure) : _is_alive_closure(is_alive_closure), _found_dead(false) {}
   template <typename T> void do_oop_work(T* p) {
     T heap_oop = oopDesc::load_heap_oop(p);
     if (!oopDesc::is_null(heap_oop)) {
       oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
       if (!_is_alive_closure->do_object_b(obj)) {
         _found_dead = true;
       }
     }
   }
   void do_oop(oop* p)       { do_oop_work<oop>(p); }
   void do_oop(narrowOop* p) { do_oop_work<narrowOop>(p); }
   bool found_dead()         { return _found_dead; }
 };
 #endif
 oop ClassLoaderData::keep_alive_object() const {
   assert(!keep_alive(), "Don't use with CLDs that are artificially kept alive");
   return is_anonymous() ? _klasses->java_mirror() : class_loader();
 }
 bool ClassLoaderData::is_alive(BoolObjectClosure* is_alive_closure) const {
   bool alive = keep_alive() // null class loader and incomplete anonymous klasses.
       || is_alive_closure->do_object_b(keep_alive_object());
 #ifdef ASSERT
   if (alive) {
     AllAliveClosure all_alive_closure(is_alive_closure);
     KlassToOopClosure klass_closure(&all_alive_closure);
     const_cast<ClassLoaderData*>(this)->oops_do(&all_alive_closure, &klass_closure, false);
     assert(!all_alive_closure.found_dead(), err_msg("Found dead oop in alive cld: " PTR_FORMAT, p2i(this)));
   }
 #endif
   return alive;
 }
 ClassLoaderData::~ClassLoaderData() {
   // Release C heap structures for all the classes.
   classes_do(InstanceKlass::release_C_heap_structures);
   Metaspace *m = _metaspace;
   if (m != NULL) {
     _metaspace = NULL;
     // release the metaspace
     delete m;
     // release the handles
     if (_handles != NULL) {
       JNIHandleBlock::release_block(_handles);
       _handles = NULL;
     }
   }
   // Clear all the JNI handles for methods
   // These aren't deallocated and are going to look like a leak, but that's
   // needed because we can't really get rid of jmethodIDs because we don't
   // know when native code is going to stop using them.  The spec says that
   // they're "invalid" but existing programs likely rely on their being
   // NULL after class unloading.
   if (_jmethod_ids != NULL) {
     Method::clear_jmethod_ids(this);
   }
   // Delete lock
   delete _metaspace_lock;
   // Delete free list
   if (_deallocate_list != NULL) {
     delete _deallocate_list;
   }
 }
 /**
  * Returns true if this class loader data is for the extension class loader.
  */
 bool ClassLoaderData::is_ext_class_loader_data() const {
   return SystemDictionary::is_ext_class_loader(class_loader());
 }
 Metaspace* ClassLoaderData::metaspace_non_null() {
   assert(!DumpSharedSpaces, "wrong metaspace!");
   // If the metaspace has not been allocated, create a new one.  Might want
   // to create smaller arena for Reflection class loaders also.
   // The reason for the delayed allocation is because some class loaders are
   // simply for delegating with no metadata of their own.
   if (_metaspace == NULL) {
     MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
     // Check again if metaspace has been allocated while we were getting this lock.
     if (_metaspace != NULL) {
       return _metaspace;
     }
     if (this == the_null_class_loader_data()) {
       assert (class_loader() == NULL, "Must be");
       set_metaspace(new Metaspace(_metaspace_lock, Metaspace::BootMetaspaceType));
     } else if (is_anonymous()) {
       if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
         tty->print_cr("is_anonymous: %s", class_loader()->klass()->internal_name());
       }
       set_metaspace(new Metaspace(_metaspace_lock, Metaspace::AnonymousMetaspaceType));
     } else if (class_loader()->is_a(SystemDictionary::reflect_DelegatingClassLoader_klass())) {
       if (TraceClassLoaderData && Verbose && class_loader() != NULL) {
         tty->print_cr("is_reflection: %s", class_loader()->klass()->internal_name());
       }
       set_metaspace(new Metaspace(_metaspace_lock, Metaspace::ReflectionMetaspaceType));
     } else {
       set_metaspace(new Metaspace(_metaspace_lock, Metaspace::StandardMetaspaceType));
     }
   }
   return _metaspace;
 }
 JNIHandleBlock* ClassLoaderData::handles() const           { return _handles; }
 void ClassLoaderData::set_handles(JNIHandleBlock* handles) { _handles = handles; }
 jobject ClassLoaderData::add_handle(Handle h) {
   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
   if (handles() == NULL) {
     set_handles(JNIHandleBlock::allocate_block());
   }
   return handles()->allocate_handle(h());
 }
 // Add this metadata pointer to be freed when it's safe.  This is only during
 // class unloading because Handles might point to this metadata field.
 void ClassLoaderData::add_to_deallocate_list(Metadata* m) {
   // Metadata in shared region isn't deleted.
   if (!m->is_shared()) {
     MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
     if (_deallocate_list == NULL) {
       _deallocate_list = new (ResourceObj::C_HEAP, mtClass) GrowableArray<Metadata*>(100, true);
     }
     _deallocate_list->append_if_missing(m);
   }
 }
 // Deallocate free metadata on the free list.  How useful the PermGen was!
 void ClassLoaderData::free_deallocate_list() {
   // Don't need lock, at safepoint
   assert(SafepointSynchronize::is_at_safepoint(), "only called at safepoint");
   if (_deallocate_list == NULL) {
     return;
   }
   // Go backwards because this removes entries that are freed.
   for (int i = _deallocate_list->length() - 1; i >= 0; i--) {
     Metadata* m = _deallocate_list->at(i);
     if (!m->on_stack()) {
       _deallocate_list->remove_at(i);
       // There are only three types of metadata that we deallocate directly.
       // Cast them so they can be used by the template function.
       if (m->is_method()) {
         MetadataFactory::free_metadata(this, (Method*)m);
       } else if (m->is_constantPool()) {
         MetadataFactory::free_metadata(this, (ConstantPool*)m);
       } else if (m->is_klass()) {
         MetadataFactory::free_metadata(this, (InstanceKlass*)m);
       } else {
         ShouldNotReachHere();
       }
     }
   }
 }
 // These anonymous class loaders are to contain classes used for JSR292
 ClassLoaderData* ClassLoaderData::anonymous_class_loader_data(oop loader, TRAPS) {
   // Add a new class loader data to the graph.
   return ClassLoaderDataGraph::add(loader, true, CHECK_NULL);
 }
 const char* ClassLoaderData::loader_name() {
   // Handles null class loader
   return SystemDictionary::loader_name(class_loader());
 }
 #ifndef PRODUCT
 // Define to dump klasses
 #undef CLD_DUMP_KLASSES
 void ClassLoaderData::dump(outputStream * const out) {
   ResourceMark rm;
   out->print("ClassLoaderData CLD: "PTR_FORMAT", loader: "PTR_FORMAT", loader_klass: "PTR_FORMAT" %s {",
       p2i(this), p2i((void *)class_loader()),
       p2i(class_loader() != NULL ? class_loader()->klass() : NULL), loader_name());
   if (claimed()) out->print(" claimed ");
   if (is_unloading()) out->print(" unloading ");
   out->print(" handles " INTPTR_FORMAT, p2i(handles()));
   out->cr();
   if (metaspace_or_null() != NULL) {
     out->print_cr("metaspace: " INTPTR_FORMAT, p2i(metaspace_or_null()));
     metaspace_or_null()->dump(out);
   } else {
     out->print_cr("metaspace: NULL");
   }
 #ifdef CLD_DUMP_KLASSES
   if (Verbose) {
     ResourceMark rm;
     Klass* k = _klasses;
     while (k != NULL) {
       out->print_cr("klass "PTR_FORMAT", %s, CT: %d, MUT: %d", k, k->name()->as_C_string(),
           k->has_modified_oops(), k->has_accumulated_modified_oops());
       assert(k != k->next_link(), "no loops!");
       k = k->next_link();
     }
   }
 #endif  // CLD_DUMP_KLASSES
 #undef CLD_DUMP_KLASSES
   if (_jmethod_ids != NULL) {
     Method::print_jmethod_ids(this, out);
   }
   out->print_cr("}");
 }
 #endif // PRODUCT
 void ClassLoaderData::verify() {
   oop cl = class_loader();
   guarantee(this == class_loader_data(cl) || is_anonymous(), "Must be the same");
   guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data() || is_anonymous(), "must be");
   // Verify the integrity of the allocated space.
   if (metaspace_or_null() != NULL) {
     metaspace_or_null()->verify();
   }
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     guarantee(k->class_loader_data() == this, "Must be the same");
     k->verify();
     assert(k != k->next_link(), "no loops!");
   }
 }
 bool ClassLoaderData::contains_klass(Klass* klass) {
   for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
     if (k == klass) return true;
   }
   return false;
 }
 // GC root of class loader data created.
 ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
 ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
 ClassLoaderData* ClassLoaderDataGraph::_saved_unloading = NULL;
 ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
 bool ClassLoaderDataGraph::_should_purge = false;
 // Add a new class loader data node to the list.  Assign the newly created
 // ClassLoaderData into the java/lang/ClassLoader object as a hidden field
 ClassLoaderData* ClassLoaderDataGraph::add(Handle loader, bool is_anonymous, TRAPS) {
   // We need to allocate all the oops for the ClassLoaderData before allocating the
   // actual ClassLoaderData object.
   ClassLoaderData::Dependencies dependencies(CHECK_NULL);
   No_Safepoint_Verifier no_safepoints; // we mustn't GC until we've installed the
                                        // ClassLoaderData in the graph since the CLD
                                        // contains unhandled oops
   ClassLoaderData* cld = new ClassLoaderData(loader, is_anonymous, dependencies);
   if (!is_anonymous) {
     ClassLoaderData** cld_addr = java_lang_ClassLoader::loader_data_addr(loader());
     // First, Atomically set it
     ClassLoaderData* old = (ClassLoaderData*) Atomic::cmpxchg_ptr(cld, cld_addr, NULL);
     if (old != NULL) {
       delete cld;
       // Returns the data.
       return old;
     }
   }
   // We won the race, and therefore the task of adding the data to the list of
   // class loader data
   ClassLoaderData** list_head = &_head;
   ClassLoaderData* next = _head;
   do {
     cld->set_next(next);
     ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
     if (exchanged == next) {
       if (TraceClassLoaderData) {
         ResourceMark rm;
         tty->print("[ClassLoaderData: ");
         tty->print("create class loader data " INTPTR_FORMAT, p2i(cld));
         tty->print(" for instance " INTPTR_FORMAT " of %s", p2i((void *)cld->class_loader()),
                    cld->loader_name());
         tty->print_cr("]");
       }
       return cld;
     }
     next = exchanged;
   } while (true);
 }
 void ClassLoaderDataGraph::oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     cld->oops_do(f, klass_closure, must_claim);
   }
 }
 void ClassLoaderDataGraph::keep_alive_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     if (cld->keep_alive()) {
       cld->oops_do(f, klass_closure, must_claim);
     }
   }
 }
 void ClassLoaderDataGraph::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
   if (ClassUnloading) {
     keep_alive_oops_do(f, klass_closure, must_claim);
   } else {
     oops_do(f, klass_closure, must_claim);
   }
 }
 void ClassLoaderDataGraph::cld_do(CLDClosure* cl) {
   for (ClassLoaderData* cld = _head; cl != NULL && cld != NULL; cld = cld->next()) {
     cl->do_cld(cld);
   }
 }
 void ClassLoaderDataGraph::roots_cld_do(CLDClosure* strong, CLDClosure* weak) {
   for (ClassLoaderData* cld = _head;  cld != NULL; cld = cld->_next) {
     CLDClosure* closure = cld->keep_alive() ? strong : weak;
     if (closure != NULL) {
       closure->do_cld(cld);
     }
   }
 }
 void ClassLoaderDataGraph::keep_alive_cld_do(CLDClosure* cl) {
   roots_cld_do(cl, NULL);
 }
 void ClassLoaderDataGraph::always_strong_cld_do(CLDClosure* cl) {
   if (ClassUnloading) {
     keep_alive_cld_do(cl);
   } else {
     cld_do(cl);
   }
 }
 void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     cld->classes_do(klass_closure);
   }
 }
 void ClassLoaderDataGraph::classes_do(void f(Klass* const)) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     cld->classes_do(f);
   }
 }
 void ClassLoaderDataGraph::loaded_classes_do(KlassClosure* klass_closure) {
   for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
     cld->loaded_classes_do(klass_closure);
   }
 }
 void ClassLoaderDataGraph::classes_unloading_do(void f(Klass* const)) {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
   // Only walk the head until any clds not purged from prior unloading
   // (CMS doesn't purge right away).
   for (ClassLoaderData* cld = _unloading; cld != _saved_unloading; cld = cld->next()) {
     cld->classes_do(f);
   }
 }
 GrowableArray<ClassLoaderData*>* ClassLoaderDataGraph::new_clds() {
   assert(_head == NULL || _saved_head != NULL, "remember_new_clds(true) not called?");
   GrowableArray<ClassLoaderData*>* array = new GrowableArray<ClassLoaderData*>();
   // The CLDs in [_head, _saved_head] were all added during last call to remember_new_clds(true);
   ClassLoaderData* curr = _head;
   while (curr != _saved_head) {
     if (!curr->claimed()) {
       array->push(curr);
       if (TraceClassLoaderData) {
         tty->print("[ClassLoaderData] found new CLD: ");
         curr->print_value_on(tty);
         tty->cr();
       }
     }
     curr = curr->_next;
   }
   return array;
 }
 bool ClassLoaderDataGraph::unload_list_contains(const void* x) {
   assert(SafepointSynchronize::is_at_safepoint(), "only safe to call at safepoint");
   for (ClassLoaderData* cld = _unloading; cld != NULL; cld = cld->next()) {
     if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
       return true;
     }
   }
   return false;
 }
 #ifndef PRODUCT
 bool ClassLoaderDataGraph::contains_loader_data(ClassLoaderData* loader_data) {
   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
     if (loader_data == data) {
       return true;
     }
   }
   return false;
 }
 #endif // PRODUCT
 // Move class loader data from main list to the unloaded list for unloading
 // and deallocation later.
 bool ClassLoaderDataGraph::do_unloading(BoolObjectClosure* is_alive_closure) {
   ClassLoaderData* data = _head;
   ClassLoaderData* prev = NULL;
   bool seen_dead_loader = false;
   // Save previous _unloading pointer for CMS which may add to unloading list before
   // purging and we don't want to rewalk the previously unloaded class loader data.
   _saved_unloading = _unloading;
   // mark metadata seen on the stack and code cache so we can delete
   // unneeded entries.
   bool has_redefined_a_class = JvmtiExport::has_redefined_a_class();
   MetadataOnStackMark md_on_stack;
   while (data != NULL) {
     if (data->is_alive(is_alive_closure)) {
       if (has_redefined_a_class) {
         data->classes_do(InstanceKlass::purge_previous_versions);
       }
       data->free_deallocate_list();
       prev = data;
       data = data->next();
       continue;
     }
     seen_dead_loader = true;
     ClassLoaderData* dead = data;
     dead->unload();
     data = data->next();
     // Remove from loader list.
     // This class loader data will no longer be found
     // in the ClassLoaderDataGraph.
     if (prev != NULL) {
       prev->set_next(data);
     } else {
       assert(dead == _head, "sanity check");
       _head = data;
     }
     dead->set_next(_unloading);
     _unloading = dead;
   }
   if (seen_dead_loader) {
     post_class_unload_events();
   }
   return seen_dead_loader;
 }
 void ClassLoaderDataGraph::purge() {
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
   ClassLoaderData* list = _unloading;
   _unloading = NULL;
   ClassLoaderData* next = list;
   while (next != NULL) {
     ClassLoaderData* purge_me = next;
     next = purge_me->next();
     delete purge_me;
   }
   Metaspace::purge();
 }
 void ClassLoaderDataGraph::post_class_unload_events(void) {
 #if INCLUDE_TRACE
   assert(SafepointSynchronize::is_at_safepoint(), "must be at safepoint!");
   if (Tracing::enabled()) {
     if (Tracing::is_event_enabled(TraceClassUnloadEvent)) {
       assert(_unloading != NULL, "need class loader data unload list!");
       _class_unload_time = Ticks::now();
       classes_unloading_do(&class_unload_event);
     }
     Tracing::on_unloading_classes();
   }
 #endif
 }
 // CDS support
 // Global metaspaces for writing information to the shared archive.  When
 // application CDS is supported, we may need one per metaspace, so this
 // sort of looks like it.
 Metaspace* ClassLoaderData::_ro_metaspace = NULL;
 Metaspace* ClassLoaderData::_rw_metaspace = NULL;
 static bool _shared_metaspaces_initialized = false;
 // Initialize shared metaspaces (change to call from somewhere not lazily)
 void ClassLoaderData::initialize_shared_metaspaces() {
   assert(DumpSharedSpaces, "only use this for dumping shared spaces");
   assert(this == ClassLoaderData::the_null_class_loader_data(),
          "only supported for null loader data for now");
   assert (!_shared_metaspaces_initialized, "only initialize once");
   MutexLockerEx ml(metaspace_lock(),  Mutex::_no_safepoint_check_flag);
   _ro_metaspace = new Metaspace(_metaspace_lock, Metaspace::ROMetaspaceType);
   _rw_metaspace = new Metaspace(_metaspace_lock, Metaspace::ReadWriteMetaspaceType);
   _shared_metaspaces_initialized = true;
 }
 Metaspace* ClassLoaderData::ro_metaspace() {
   assert(_ro_metaspace != NULL, "should already be initialized");
   return _ro_metaspace;
 }
 Metaspace* ClassLoaderData::rw_metaspace() {
   assert(_rw_metaspace != NULL, "should already be initialized");
   return _rw_metaspace;
 }
 ClassLoaderDataGraphKlassIteratorAtomic::ClassLoaderDataGraphKlassIteratorAtomic()
     : _next_klass(NULL) {
   ClassLoaderData* cld = ClassLoaderDataGraph::_head;
   Klass* klass = NULL;
   // Find the first klass in the CLDG.
   while (cld != NULL) {
     klass = cld->_klasses;
     if (klass != NULL) {
       _next_klass = klass;
       return;
     }
     cld = cld->next();
   }
 }
 Klass* ClassLoaderDataGraphKlassIteratorAtomic::next_klass_in_cldg(Klass* klass) {
   Klass* next = klass->next_link();
   if (next != NULL) {
     return next;
   }
   // No more klasses in the current CLD. Time to find a new CLD.
   ClassLoaderData* cld = klass->class_loader_data();
   while (next == NULL) {
     cld = cld->next();
     if (cld == NULL) {
       break;
     }
     next = cld->_klasses;
   }
   return next;
 }
 Klass* ClassLoaderDataGraphKlassIteratorAtomic::next_klass() {
   Klass* head = (Klass*)_next_klass;
   while (head != NULL) {
     Klass* next = next_klass_in_cldg(head);
     Klass* old_head = (Klass*)Atomic::cmpxchg_ptr(next, &_next_klass, head);
     if (old_head == head) {
       return head; // Won the CAS.
     }
     head = old_head;
   }
   // Nothing more for the iterator to hand out.
   assert(head == NULL, err_msg("head is " PTR_FORMAT ", expected not null:", p2i(head)));
   return NULL;
 }
 ClassLoaderDataGraphMetaspaceIterator::ClassLoaderDataGraphMetaspaceIterator() {
   _data = ClassLoaderDataGraph::_head;
 }
 ClassLoaderDataGraphMetaspaceIterator::~ClassLoaderDataGraphMetaspaceIterator() {}
 #ifndef PRODUCT
 // callable from debugger
 extern "C" int print_loader_data_graph() {
   ClassLoaderDataGraph::dump_on(tty);
   return 0;
 }
 void ClassLoaderDataGraph::verify() {
   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
     data->verify();
   }
 }
 void ClassLoaderDataGraph::dump_on(outputStream * const out) {
   for (ClassLoaderData* data = _head; data != NULL; data = data->next()) {
     data->dump(out);
   }
   MetaspaceAux::dump(out);
 }
 #endif // PRODUCT
 void ClassLoaderData::print_value_on(outputStream* out) const {
   if (class_loader() == NULL) {
     out->print("NULL class_loader");
   } else {
     out->print("class loader " INTPTR_FORMAT, p2i(this));
     class_loader()->print_value_on(out);
   }
 }
 #if INCLUDE_TRACE
 Ticks ClassLoaderDataGraph::_class_unload_time;
 void ClassLoaderDataGraph::class_unload_event(Klass* const k) {
   // post class unload event
   EventClassUnload event(UNTIMED);
   event.set_endtime(_class_unload_time);
   event.set_unloadedClass(k);
   oop defining_class_loader = k->class_loader();
   event.set_definingClassLoader(defining_class_loader != NULL ?
                                 defining_class_loader->klass() : (Klass*)NULL);
   event.commit();
 }
 #endif /* INCLUDE_TRACE */

Mercurial > jdk8-mips64-public > hotspot / annotate

src/share/vm/classfile/classLoaderData.cpp@2c6ef90f030a (annotated)

src/share/vm/classfile/classLoaderData.cpp