/* * Copyright (c) 2002, 2022, 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. *
*/
inlinevoid KlassInfoEntry::add_subclass(KlassInfoEntry* cie) { if (_subclasses == NULL) {
_subclasses = new (mtServiceability) GrowableArray<KlassInfoEntry*>(4, mtServiceability);
}
_subclasses->append(cie);
}
int KlassInfoEntry::compare(KlassInfoEntry* e1, KlassInfoEntry* e2) { if(e1->_instance_words > e2->_instance_words) { return -1;
} elseif(e1->_instance_words < e2->_instance_words) { return 1;
} // Sort alphabetically, note 'Z' < '[' < 'a', but it's better to group // the array classes before all the instance classes.
ResourceMark rm; constchar* name1 = e1->klass()->external_name(); constchar* name2 = e2->klass()->external_name(); bool d1 = (name1[0] == JVM_SIGNATURE_ARRAY); bool d2 = (name2[0] == JVM_SIGNATURE_ARRAY); if (d1 && !d2) { return -1;
} elseif (d2 && !d1) { return 1;
} else { return strcmp(name1, name2);
}
}
constchar* KlassInfoEntry::name() const { constchar* name; if (_klass->name() != NULL) {
name = _klass->external_name();
} else { if (_klass == Universe::boolArrayKlassObj()) name = ""; else if (_klass == Universe::charArrayKlassObj()) name = ""; else if (_klass == Universe::floatArrayKlassObj()) name = ""; else if (_klass == Universe::doubleArrayKlassObj()) name = ""; else if (_klass == Universe::byteArrayKlassObj()) name = ""; else if (_klass == Universe::shortArrayKlassObj()) name = ""; else if (_klass == Universe::intArrayKlassObj()) name = ""; else if (_klass == Universe::longArrayKlassObj()) name = ""; else
name = "";
} return name;
}
KlassInfoEntry* KlassInfoBucket::lookup(Klass* const k) { // Can happen if k is an archived class that we haven't loaded yet. if (k->java_mirror_no_keepalive() == NULL) { return NULL;
}
KlassInfoEntry* elt = _list; while (elt != NULL) { if (elt->is_equal(k)) { return elt;
}
elt = elt->next();
}
elt = new (std::nothrow) KlassInfoEntry(k, list()); // We may be out of space to allocate the new entry. if (elt != NULL) {
set_list(elt);
} return elt;
}
class KlassInfoTable::AllClassesFinder : public LockedClassesDo {
KlassInfoTable *_table; public:
AllClassesFinder(KlassInfoTable* table) : _table(table) {} virtualvoid do_klass(Klass* k) { // This has the SIDE EFFECT of creating a KlassInfoEntry // for <k>, if one doesn't exist yet.
_table->lookup(k);
}
};
KlassInfoTable::KlassInfoTable(bool add_all_classes) {
_size_of_instances_in_words = 0;
_ref = (HeapWord*) Universe::boolArrayKlassObj();
_buckets =
(KlassInfoBucket*) AllocateHeap(sizeof(KlassInfoBucket) * _num_buckets,
mtInternal, CURRENT_PC, AllocFailStrategy::RETURN_NULL); if (_buckets != NULL) { for (int index = 0; index < _num_buckets; index++) {
_buckets[index].initialize();
} if (add_all_classes) {
AllClassesFinder finder(this);
ClassLoaderDataGraph::classes_do(&finder);
}
}
}
KlassInfoTable::~KlassInfoTable() { if (_buckets != NULL) { for (int index = 0; index < _num_buckets; index++) {
_buckets[index].empty();
}
FREE_C_HEAP_ARRAY(KlassInfoBucket, _buckets);
_buckets = NULL;
}
}
KlassInfoEntry* KlassInfoTable::lookup(Klass* k) {
uint idx = hash(k) % _num_buckets;
assert(_buckets != NULL, "Allocation failure should have been caught");
KlassInfoEntry* e = _buckets[idx].lookup(k); // Lookup may fail if this is a new klass for which we // could not allocate space for an new entry, or if it's // an archived class that we haven't loaded yet.
assert(e == NULL || k == e->klass(), "must be equal"); return e;
}
// Return false if the entry could not be recorded on account // of running out of space required to create a new entry. bool KlassInfoTable::record_instance(const oop obj) {
Klass* k = obj->klass();
KlassInfoEntry* elt = lookup(k); // elt may be NULL if it's a new klass for which we // could not allocate space for a new entry in the hashtable. if (elt != NULL) {
elt->set_count(elt->count() + 1);
elt->set_words(elt->words() + obj->size());
_size_of_instances_in_words += obj->size(); returntrue;
} else { returnfalse;
}
}
void KlassInfoTable::iterate(KlassInfoClosure* cic) {
assert(_buckets != NULL, "Allocation failure should have been caught"); for (int index = 0; index < _num_buckets; index++) {
_buckets[index].iterate(cic);
}
}
// Return false if the entry could not be recorded on account // of running out of space required to create a new entry. bool KlassInfoTable::merge_entry(const KlassInfoEntry* cie) {
Klass* k = cie->klass();
KlassInfoEntry* elt = lookup(k); // elt may be NULL if it's a new klass for which we // could not allocate space for a new entry in the hashtable. if (elt != NULL) {
elt->set_count(elt->count() + cie->count());
elt->set_words(elt->words() + cie->words());
_size_of_instances_in_words += cie->words(); returntrue;
} returnfalse;
}
// Add all classes to the KlassInfoTable, which allows for quick lookup. // A KlassInfoEntry will be created for each class.
KlassInfoTable cit(true); if (cit.allocation_failed()) {
st->print_cr("ERROR: Ran out of C-heap; hierarchy not generated"); return;
}
// Add all created KlassInfoEntry instances to the elements array for easy // iteration, and to allow each KlassInfoEntry instance to have a unique index.
HierarchyClosure hc(&elements);
cit.iterate(&hc);
for(int i = 0; i < elements.length(); i++) {
KlassInfoEntry* cie = elements.at(i);
Klass* super = cie->klass()->super();
// Set the index for the class.
cie->set_index(i + 1);
// Add the class to the subclass array of its superclass. if (super != NULL) {
KlassInfoEntry* super_cie = cit.lookup(super);
assert(super_cie != NULL, "could not lookup superclass");
super_cie->add_subclass(cie);
}
}
// Set the do_print flag for each class that should be printed. for(int i = 0; i < elements.length(); i++) {
KlassInfoEntry* cie = elements.at(i); if (classname == NULL) { // We are printing all classes.
cie->set_do_print(true);
} else { // We are only printing the hierarchy of a specific class. if (strcmp(classname, cie->klass()->external_name()) == 0) {
KlassHierarchy::set_do_print_for_class_hierarchy(cie, &cit, print_subclasses);
}
}
}
// Now we do a depth first traversal of the class hierachry. The class_stack will // maintain the list of classes we still need to process. Start things off // by priming it with java.lang.Object.
KlassInfoEntry* jlo_cie = cit.lookup(vmClasses::Object_klass());
assert(jlo_cie != NULL, "could not lookup java.lang.Object");
class_stack.push(jlo_cie);
// Repeatedly pop the top item off the stack, print its class info, // and push all of its subclasses on to the stack. Do this until there // are no classes left on the stack. while (!class_stack.is_empty()) {
KlassInfoEntry* curr_cie = class_stack.pop(); if (curr_cie->do_print()) {
print_class(st, curr_cie, print_interfaces); if (curr_cie->subclasses() != NULL) { // Current class has subclasses, so push all of them onto the stack. for (int i = 0; i < curr_cie->subclasses()->length(); i++) {
KlassInfoEntry* cie = curr_cie->subclasses()->at(i); if (cie->do_print()) {
class_stack.push(cie);
}
}
}
}
}
st->flush();
}
// Sets the do_print flag for every superclass and subclass of the specified class. void KlassHierarchy::set_do_print_for_class_hierarchy(KlassInfoEntry* cie, KlassInfoTable* cit, bool print_subclasses) { // Set do_print for all superclasses of this class.
Klass* super = ((InstanceKlass*)cie->klass())->java_super(); while (super != NULL) {
KlassInfoEntry* super_cie = cit->lookup(super);
super_cie->set_do_print(true);
super = super->super();
}
// Set do_print for this class and all of its subclasses.
Stack <KlassInfoEntry*, mtClass> class_stack;
class_stack.push(cie); while (!class_stack.is_empty()) {
KlassInfoEntry* curr_cie = class_stack.pop();
curr_cie->set_do_print(true); if (print_subclasses && curr_cie->subclasses() != NULL) { // Current class has subclasses, so push all of them onto the stack. for (int i = 0; i < curr_cie->subclasses()->length(); i++) {
KlassInfoEntry* cie = curr_cie->subclasses()->at(i);
class_stack.push(cie);
}
}
}
}
staticvoid print_indent(outputStream* st, int indent) { while (indent != 0) {
st->print("|");
indent--; if (indent != 0) {
st->print(" ");
}
}
}
// Print the class name and its unique ClassLoader identifier. staticvoid print_classname(outputStream* st, Klass* klass) {
oop loader_oop = klass->class_loader_data()->class_loader();
st->print("%s/", klass->external_name()); if (loader_oop == NULL) {
st->print("null");
} else {
st->print(PTR_FORMAT, p2i(klass->class_loader_data()));
}
}
void KlassHierarchy::print_class(outputStream* st, KlassInfoEntry* cie, bool print_interfaces) {
ResourceMark rm;
InstanceKlass* klass = (InstanceKlass*)cie->klass(); int indent = 0;
// Print indentation with proper indicators of superclass.
Klass* super = klass->super(); while (super != NULL) {
super = super->super();
indent++;
}
print_indent(st, indent); if (indent != 0) st->print("--");
// Print the class name, its unique ClassLoader identifier, and if it is an interface.
print_classname(st, klass); if (klass->is_interface()) {
st->print(" (intf)");
}
st->print("\n");
// Print any interfaces the class has. if (print_interfaces) {
Array<InstanceKlass*>* local_intfs = klass->local_interfaces();
Array<InstanceKlass*>* trans_intfs = klass->transitive_interfaces(); for (int i = 0; i < local_intfs->length(); i++) {
print_interface(st, local_intfs->at(i), "declared", indent);
} for (int i = 0; i < trans_intfs->length(); i++) {
InstanceKlass* trans_interface = trans_intfs->at(i); // Only print transitive interfaces if they are not also declared. if (!local_intfs->contains(trans_interface)) {
print_interface(st, trans_interface, "inherited", indent);
}
}
}
}
void KlassInfoHisto::print_histo_on(outputStream* st) {
st->print_cr(" num #instances #bytes class name (module)");
st->print_cr("-------------------------------------------------------");
print_elements(st);
}
class HistoClosure : public KlassInfoClosure { private:
KlassInfoHisto* _cih; public:
HistoClosure(KlassInfoHisto* cih) : _cih(cih) {}
// Heap inspection for every worker. // When native OOM happens for KlassInfoTable, set _success to false. void ParHeapInspectTask::work(uint worker_id) {
uintx missed_count = 0; bool merge_success = true; if (!Atomic::load(&_success)) { // other worker has failed on parallel iteration. return;
}
WorkerThreads* workers = Universe::heap()->safepoint_workers(); if (workers != NULL) { // The GC provided a WorkerThreads to be used during a safepoint.
// Can't run with more threads than provided by the WorkerThreads. const uint capped_parallel_thread_num = MIN2(parallel_thread_num, workers->max_workers());
WithActiveWorkers with_active_workers(workers, capped_parallel_thread_num);
ParallelObjectIterator poi(workers->active_workers());
ParHeapInspectTask task(&poi, cit, filter); // Run task with the active workers.
workers->run_task(&task); if (task.success()) { return task.missed_count();
}
}
}
ResourceMark rm; // If no parallel iteration available, run serially.
RecordInstanceClosure ric(cit, filter);
Universe::heap()->object_iterate(&ric); return ric.missed_count();
}
KlassInfoTable cit(false); if (!cit.allocation_failed()) { // populate table with object allocation info
uintx missed_count = populate_table(&cit, NULL, parallel_thread_num); if (missed_count != 0) {
log_info(gc, classhisto)("WARNING: Ran out of C-heap; undercounted " UINTX_FORMAT " total instances in data below",
missed_count);
}
// Sort and print klass instance info
KlassInfoHisto histo(&cit);
HistoClosure hc(&histo);
cit.iterate(&hc);
histo.sort();
histo.print_histo_on(st);
} else {
st->print_cr("ERROR: Ran out of C-heap; histogram not generated");
}
st->flush();
}
class FindInstanceClosure : public ObjectClosure { private:
Klass* _klass;
GrowableArray<oop>* _result;
void do_object(oop obj) { if (obj->is_a(_klass)) { // obj was read with AS_NO_KEEPALIVE, or equivalent. // The object needs to be kept alive when it is published.
Universe::heap()->keep_alive(obj);
_result->append(obj);
}
}
};
void HeapInspection::find_instances_at_safepoint(Klass* k, GrowableArray<oop>* result) {
assert(SafepointSynchronize::is_at_safepoint(), "all threads are stopped");
assert(Heap_lock->is_locked(), "should have the Heap_lock");
// Ensure that the heap is parsable
Universe::heap()->ensure_parsability(false); // no need to retire TALBs
// Iterate over objects in the heap
FindInstanceClosure fic(k, result);
Universe::heap()->object_iterate(&fic);
}
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