graal-compiler: src/share/vm/classfile/classLoaderData.cpp comparison

comparison src/share/vm/classfile/classLoaderData.cpp @ 6725:da91efe96a93

6964458: Reimplement class meta-data storage to use native memory Summary: Remove PermGen, allocate meta-data in metaspace linked to class loaders, rewrite GC walking, rewrite and rename metadata to be C++ classes Reviewed-by: jmasa, stefank, never, coleenp, kvn, brutisso, mgerdin, dholmes, jrose, twisti, roland Contributed-by: jmasa <jon.masamitsu@oracle.com>, stefank <stefan.karlsson@oracle.com>, mgerdin <mikael.gerdin@oracle.com>, never <tom.rodriguez@oracle.com>

author	coleenp
date	Sat, 01 Sep 2012 13:25:18 -0400
parents
children	90273fc0a981

comparison

equal deleted inserted replaced

-:36d1d483d5d6
+:da91efe96a93
+/*
+* Copyright (c) 2012, 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/systemDictionary.hpp"
+#include "code/codeCache.hpp"
+#include "memory/metadataFactory.hpp"
+#include "memory/metaspaceShared.hpp"
+#include "prims/jvmtiRedefineClasses.hpp"
+#include "runtime/jniHandles.hpp"
+#include "runtime/mutex.hpp"
+#include "runtime/safepoint.hpp"
+#include "runtime/synchronizer.hpp"
+#include "utilities/growableArray.hpp"
+#include "utilities/ostream.hpp"
+ClassLoaderData * ClassLoaderData::_the_null_class_loader_data = NULL;
+ClassLoaderData::ClassLoaderData(Handle h_class_loader) : _class_loader(h_class_loader()),
+_metaspace(NULL), _unloading(false), _klasses(NULL),
+_claimed(0), _jmethod_ids(NULL), _handles(NULL),
+_deallocate_list(NULL), _next(NULL),
+_metaspace_lock(new Mutex(Monitor::leaf+1, "Metaspace allocation lock", true)) {
+// empty
+}
+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);
+_handles->oops_do(f);
+if (klass_closure != NULL) {
+classes_do(klass_closure);
+}
+}
+void ClassLoaderData::classes_do(KlassClosure* klass_closure) {
+for (Klass* k = _klasses; k != NULL; k = k->next_link()) {
+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));
+}
+}
+}
+void ClassLoaderData::record_dependency(Klass* k, TRAPS) {
+ClassLoaderData * const from_cld = this;
+ClassLoaderData * const to_cld = k->class_loader_data();
+// Records dependency between non-null class loaders only.
+if (to_cld->is_the_null_class_loader_data() || from_cld->is_the_null_class_loader_data()) {
+return;
+}
+// Check that this dependency isn't from the same or parent class_loader
+oop to = to_cld->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
+from_cld->add_dependency(to_cld, CHECK);
+}
+bool ClassLoaderData::has_dependency(ClassLoaderData* dependency) {
+oop loader = dependency->class_loader();
+// Get objArrayOop out of the class_loader oop and see if this dependency
+// is there.  Don't safepoint!  These are all oops.
+// Dependency list is (oop class_loader, objArrayOop next)
+objArrayOop ok = (objArrayOop)java_lang_ClassLoader::dependencies(class_loader());
+while (ok != NULL) {
+if (ok->obj_at(0) == loader) {
+return true;
+}
+ok = (objArrayOop)ok->obj_at(1);
+}
+return false;
+}
+void ClassLoaderData::add_dependency(ClassLoaderData* dependency, TRAPS) {
+// Minimize the number of duplicates in the list.
+if (has_dependency(dependency)) {
+return;
+}
+// Create a new dependency node with fields for (class_loader, next)
+objArrayOop deps = oopFactory::new_objectArray(2, CHECK);
+deps->obj_at_put(0, dependency->class_loader());
+// Add this lock free, using compare and exchange, need barriers for GC
+// Do the barrier first.
+HeapWord* addr = java_lang_ClassLoader::dependencies_addr(class_loader());
+while (true) {
+oop old_dependency = java_lang_ClassLoader::dependencies(class_loader());
+deps->obj_at_put(1, old_dependency);
+oop newold = oopDesc::atomic_compare_exchange_oop((oop)deps, addr, old_dependency, true);
+if (newold == old_dependency) {
+update_barrier_set((void*)addr, (oop)deps);
+// we won the race to add this dependency
+break;
+}
+}
+}
+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 && k->class_loader_data() != NULL) {
+ResourceMark rm;
+tty->print_cr("[TraceClassLoaderData] Adding k: " PTR_FORMAT " %s to CLD: "
+PTR_FORMAT " loader: " PTR_FORMAT " %s",
+k,
+k->external_name(),
+k->class_loader_data(),
+k->class_loader(),
+k->class_loader() != NULL ? k->class_loader()->klass()->external_name() : "NULL"
+);
+}
+}
+// 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;
+}
+ShouldNotReachHere();   // should have found this class!!
+}
+ClassLoaderData::~ClassLoaderData() {
+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;
+}
+}
+Metaspace* ClassLoaderData::metaspace_non_null() {
+// 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 (class_loader() == NULL) {
+assert(this == the_null_class_loader_data(), "Must be");
+size_t word_size = Metaspace::first_chunk_word_size();
+set_metaspace(new Metaspace(_metaspace_lock, word_size));
+} else {
+set_metaspace(new Metaspace(_metaspace_lock));  // default size for now.
+}
+}
+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();
+}
+}
+}
+}
+#ifndef PRODUCT
+void ClassLoaderData::print_loader(ClassLoaderData *loader_data, outputStream* out) {
+oop class_loader = loader_data->class_loader();
+out->print("%s", SystemDictionary::loader_name(class_loader));
+}
+// 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 {",
+this, class_loader(),
+class_loader() != NULL ? class_loader()->klass() : NULL,
+class_loader() != NULL ? class_loader()->klass()->external_name() : "NULL");
+if (claimed()) out->print(" claimed ");
+if (is_unloading()) out->print(" unloading ");
+out->print(" handles " INTPTR_FORMAT, handles());
+out->cr();
+if (metaspace_or_null() != NULL) {
+out->print_cr("metaspace: " PTR_FORMAT, 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());
+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), "Must be the same");
+guarantee(cl != NULL || this == ClassLoaderData::the_null_class_loader_data(), "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();
+}
+}
+// GC root of class loader data created.
+ClassLoaderData* ClassLoaderDataGraph::_head = NULL;
+ClassLoaderData* ClassLoaderDataGraph::_unloading = NULL;
+ClassLoaderData* ClassLoaderDataGraph::_saved_head = NULL;
+// 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(ClassLoaderData** cld_addr, Handle loader_data) {
+// Not assigned a class loader data yet.
+// Create one.
+ClassLoaderData* *list_head = &_head;
+ClassLoaderData* next = _head;
+ClassLoaderData* cld = new ClassLoaderData(loader_data);
+// 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
+do {
+cld->set_next(next);
+ClassLoaderData* exchanged = (ClassLoaderData*)Atomic::cmpxchg_ptr(cld, list_head, next);
+if (exchanged == next) {
+if (TraceClassLoaderData) {
+tty->print("[ClassLoaderData: ");
+tty->print("create class loader data "PTR_FORMAT, cld);
+tty->print(" for instance "PTR_FORMAT" of ", cld->class_loader());
+loader_data->klass()->name()->print_symbol_on(tty);
+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::always_strong_oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim) {
+if (ClassUnloading) {
+ClassLoaderData::the_null_class_loader_data()->oops_do(f, klass_closure, must_claim);
+} else {
+ClassLoaderDataGraph::oops_do(f, klass_closure, must_claim);
+}
+}
+void ClassLoaderDataGraph::classes_do(KlassClosure* klass_closure) {
+for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+cld->classes_do(klass_closure);
+}
+}
+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;
+}
+#ifndef PRODUCT
+// for debugging and hsfind(x)
+bool ClassLoaderDataGraph::contains(address x) {
+// I think we need the _metaspace_lock taken here because the class loader
+// data graph could be changing while we are walking it (new entries added,
+// new entries being unloaded, etc).
+if (DumpSharedSpaces) {
+// There are only two metaspaces to worry about.
+ClassLoaderData* ncld = ClassLoaderData::the_null_class_loader_data();
+return (ncld->ro_metaspace()->contains(x) || ncld->rw_metaspace()->contains(x));
+}
+if (UseSharedSpaces && MetaspaceShared::is_in_shared_space(x)) {
+return true;
+}
+for (ClassLoaderData* cld = _head; cld != NULL; cld = cld->next()) {
+if (cld->metaspace_or_null() != NULL && cld->metaspace_or_null()->contains(x)) {
+return true;
+}
+}
+// Could also be on an unloading list which is okay, ie. still allocated
+// for a little while.
+for (ClassLoaderData* ucld = _unloading; ucld != NULL; ucld = ucld->next()) {
+if (ucld->metaspace_or_null() != NULL && ucld->metaspace_or_null()->contains(x)) {
+return true;
+}
+}
+return false;
+}
+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) {
+ClassLoaderData* data = _head;
+ClassLoaderData* prev = NULL;
+bool seen_dead_loader = false;
+// 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->class_loader() == NULL || is_alive->do_object_b(data->class_loader())) {
+assert(data->claimed(), "class loader data must have been claimed");
+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->mark_for_unload();
+if (TraceClassLoaderData) {
+tty->print("[ClassLoaderData: unload loader data "PTR_FORMAT, dead);
+tty->print(" for instance "PTR_FORMAT" of ", dead->class_loader());
+dead->class_loader()->klass()->name()->print_symbol_on(tty);
+tty->print_cr("]");
+}
+data = data->next();
+// Remove from loader list.
+if (prev != NULL) {
+prev->set_next(data);
+} else {
+assert(dead == _head, "sanity check");
+_head = data;
+}
+dead->set_next(_unloading);
+_unloading = dead;
+}
+return seen_dead_loader;
+}
+void ClassLoaderDataGraph::purge() {
+ClassLoaderData* list = _unloading;
+_unloading = NULL;
+ClassLoaderData* next = list;
+while (next != NULL) {
+ClassLoaderData* purge_me = next;
+next = purge_me->next();
+delete purge_me;
+}
+}
+// 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, SharedReadOnlySize/wordSize);
+_rw_metaspace = new Metaspace(_metaspace_lock, SharedReadWriteSize/wordSize);
+_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;
+}
+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);
+}
+void ClassLoaderData::print_value_on(outputStream* out) const {
+if (class_loader() == NULL) {
+out->print_cr("NULL class_loader");
+} else {
+out->print("class loader "PTR_FORMAT, this);
+class_loader()->print_value_on(out);
+}
+}
+#endif // PRODUCT

Mercurial > hg > graal-compiler

comparison src/share/vm/classfile/classLoaderData.cpp @ 6725:da91efe96a93