1 /*
  2  * Copyright (c) 2014, 2026, Oracle and/or its affiliates. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
 22  *
 23  */
 24 
 25 #include "classfile/classLoaderData.inline.hpp"
 26 #include "classfile/classLoaderDataGraph.hpp"
 27 #include "classfile/classLoaderStats.hpp"
 28 #include "memory/classLoaderMetaspace.hpp"
 29 #include "oops/objArrayKlass.hpp"
 30 #include "oops/oop.inline.hpp"
 31 #include "utilities/globalDefinitions.hpp"
 32 
 33 
 34 class ClassStatsClosure : public KlassClosure {
 35   // Some klasses should not be reported by ClassStatistics
 36   bool exclude_klass(Klass* k) const {
 37     // Direct instances of ObjArrayKlass represent the Java types that Java code can see.
 38     // RefArrayKlass/FlatArrayKlass describe different implementations of the arrays, filter them out.
 39     return k->is_objArray_klass() && k->kind() != Klass::KlassKind::ObjArrayKlassKind;
 40   }
 41 
 42 public:
 43   int _num_classes;
 44 
 45   ClassStatsClosure() :
 46     _num_classes(0) {
 47   }
 48 
 49   virtual void do_klass(Klass* k) {
 50     if (!exclude_klass(k)) {
 51       _num_classes++;
 52     }
 53   }
 54 
 55 };
 56 
 57 void ClassLoaderStatsClosure::do_cld(ClassLoaderData* cld) {
 58   // Class loaders are not kept alive so this closure must only be
 59   // used during a safepoint.
 60   assert_at_safepoint();
 61   oop cl = cld->class_loader_no_keepalive();
 62 
 63   // The hashtable key is the ClassLoader oop since we want to account
 64   // for "real" classes and hidden classes together
 65   bool added = false;
 66   ClassLoaderStats* cls = _stats->put_if_absent(cl, &added);
 67   if (added) {
 68     cls->_class_loader = cl;
 69     _total_loaders++;
 70   }
 71   assert(cls->_class_loader == cl, "Sanity");
 72 
 73   if (!cld->has_class_mirror_holder()) {
 74     cls->_cld = cld;
 75   }
 76 
 77   if (cl != nullptr) {
 78     cls->_parent = java_lang_ClassLoader::parent_no_keepalive(cl);
 79     addEmptyParents(cls->_parent);
 80   }
 81 
 82   ClassStatsClosure csc;
 83   cld->classes_do(&csc);
 84   bool is_hidden = false;
 85   if(cld->has_class_mirror_holder()) {
 86     // If cld has a class holder then it must be hidden.
 87     // Either way, count it as a hidden class.
 88     cls->_hidden_classes_count += csc._num_classes;
 89   } else {
 90     cls->_classes_count = csc._num_classes;
 91   }
 92   _total_classes += csc._num_classes;
 93 
 94   ClassLoaderMetaspace* ms = cld->metaspace_or_null();
 95   if (ms != nullptr) {
 96     size_t used_words, capacity_words;
 97     ms->usage_numbers(&used_words, nullptr, &capacity_words);
 98     size_t used_bytes = used_words * BytesPerWord;
 99     size_t capacity_bytes = capacity_words * BytesPerWord;
100     if(cld->has_class_mirror_holder()) {
101       cls->_hidden_chunk_sz += capacity_bytes;
102       cls->_hidden_block_sz += used_bytes;
103     } else {
104       cls->_chunk_sz = capacity_bytes;
105       cls->_block_sz = used_bytes;
106     }
107     _total_chunk_sz += capacity_bytes;
108     _total_block_sz += used_bytes;
109   }
110 }
111 
112 // Handles the difference in pointer width on 32 and 64 bit platforms
113 #ifdef _LP64
114   #define SPACE "%8s"
115 #else
116   #define SPACE "%s"
117 #endif
118 
119 
120 bool ClassLoaderStatsClosure::do_entry(oop const& key, ClassLoaderStats const& cls) {
121   Klass* class_loader_klass = (cls._class_loader == nullptr ? nullptr : cls._class_loader->klass());
122   Klass* parent_klass = (cls._parent == nullptr ? nullptr : cls._parent->klass());
123 
124   _out->print(INTPTR_FORMAT "  " INTPTR_FORMAT "  " INTPTR_FORMAT "  %6zu  %8zu  %8zu  ",
125       p2i(class_loader_klass), p2i(parent_klass), p2i(cls._cld),
126       cls._classes_count,
127       cls._chunk_sz, cls._block_sz);
128   if (class_loader_klass != nullptr) {
129     _out->print("%s", class_loader_klass->external_name());
130   } else {
131     _out->print("<boot class loader>");
132   }
133   _out->cr();
134   if (cls._hidden_classes_count > 0) {
135     _out->print_cr(SPACE SPACE SPACE "                                    %6zu  %8zu  %8zu   + hidden classes",
136         "", "", "",
137         cls._hidden_classes_count,
138         cls._hidden_chunk_sz, cls._hidden_block_sz);
139   }
140   return true;
141 }
142 
143 
144 void ClassLoaderStatsClosure::print() {
145   _out->print_cr("ClassLoader" SPACE " Parent" SPACE "      CLD*" SPACE "       Classes   ChunkSz   BlockSz  Type", "", "", "");
146   _stats->iterate(this);
147   _out->print("Total = %-6zu", _total_loaders);
148   _out->print(SPACE SPACE SPACE "                      ", "", "", "");
149   _out->print_cr("%6zu  %8zu  %8zu  ",
150       _total_classes,
151       _total_chunk_sz,
152       _total_block_sz);
153   _out->print_cr("ChunkSz: Total size of all allocated metaspace chunks");
154   _out->print_cr("BlockSz: Total size of all allocated metaspace blocks (each chunk has several blocks)");
155 }
156 
157 
158 void ClassLoaderStatsClosure::addEmptyParents(oop cl) {
159   while (cl != nullptr && java_lang_ClassLoader::loader_data_acquire(cl) == nullptr) {
160     // This classloader has not loaded any classes
161     bool added = false;
162     ClassLoaderStats* cls = _stats->put_if_absent(cl, &added);
163     if (added) {
164       cls->_class_loader = cl;
165       cls->_parent = java_lang_ClassLoader::parent_no_keepalive(cl);
166       _total_loaders++;
167     }
168     assert(cls->_class_loader == cl, "Sanity");
169 
170     cl = java_lang_ClassLoader::parent_no_keepalive(cl);
171   }
172 }
173 
174 
175 void ClassLoaderStatsVMOperation::doit() {
176   ClassLoaderStatsClosure clsc (_out);
177   ClassLoaderDataGraph::loaded_cld_do(&clsc);
178   clsc.print();
179 }
180 
181 
182 void ClassLoaderStatsDCmd::execute(DCmdSource source, TRAPS) {
183   ClassLoaderStatsVMOperation op(output());
184   VMThread::execute(&op);
185 }
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