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 if (k->is_objArray_klass() && k->kind() != Klass::KlassKind::ObjArrayKlassKind) {
40 return true;
41 }
42 return false;
43 }
44
45 public:
46 int _num_classes;
47
48 ClassStatsClosure() :
49 _num_classes(0) {
50 }
51
52 virtual void do_klass(Klass* k) {
53 if (!exclude_klass(k)) {
54 _num_classes++;
55 }
56 }
57
58 };
59
60 void ClassLoaderStatsClosure::do_cld(ClassLoaderData* cld) {
61 // Class loaders are not kept alive so this closure must only be
62 // used during a safepoint.
63 assert_at_safepoint();
64 oop cl = cld->class_loader_no_keepalive();
65
66 // The hashtable key is the ClassLoader oop since we want to account
67 // for "real" classes and hidden classes together
68 bool added = false;
69 ClassLoaderStats* cls = _stats->put_if_absent(cl, &added);
70 if (added) {
71 cls->_class_loader = cl;
72 _total_loaders++;
73 }
74 assert(cls->_class_loader == cl, "Sanity");
75
76 if (!cld->has_class_mirror_holder()) {
77 cls->_cld = cld;
78 }
79
80 if (cl != nullptr) {
81 cls->_parent = java_lang_ClassLoader::parent_no_keepalive(cl);
82 addEmptyParents(cls->_parent);
83 }
84
85 ClassStatsClosure csc;
86 cld->classes_do(&csc);
87 bool is_hidden = false;
88 if(cld->has_class_mirror_holder()) {
89 // If cld has a class holder then it must be hidden.
90 // Either way, count it as a hidden class.
91 cls->_hidden_classes_count += csc._num_classes;
92 } else {
93 cls->_classes_count = csc._num_classes;
94 }
95 _total_classes += csc._num_classes;
96
97 ClassLoaderMetaspace* ms = cld->metaspace_or_null();
98 if (ms != nullptr) {
99 size_t used_words, capacity_words;
100 ms->usage_numbers(&used_words, nullptr, &capacity_words);
101 size_t used_bytes = used_words * BytesPerWord;
102 size_t capacity_bytes = capacity_words * BytesPerWord;
103 if(cld->has_class_mirror_holder()) {
104 cls->_hidden_chunk_sz += capacity_bytes;
105 cls->_hidden_block_sz += used_bytes;
106 } else {
107 cls->_chunk_sz = capacity_bytes;
108 cls->_block_sz = used_bytes;
109 }
110 _total_chunk_sz += capacity_bytes;
111 _total_block_sz += used_bytes;
112 }
113 }
114
115 // Handles the difference in pointer width on 32 and 64 bit platforms
116 #ifdef _LP64
117 #define SPACE "%8s"
118 #else
119 #define SPACE "%s"
120 #endif
121
122
123 bool ClassLoaderStatsClosure::do_entry(oop const& key, ClassLoaderStats const& cls) {
124 Klass* class_loader_klass = (cls._class_loader == nullptr ? nullptr : cls._class_loader->klass());
125 Klass* parent_klass = (cls._parent == nullptr ? nullptr : cls._parent->klass());
126
127 _out->print(INTPTR_FORMAT " " INTPTR_FORMAT " " INTPTR_FORMAT " %6zu %8zu %8zu ",
128 p2i(class_loader_klass), p2i(parent_klass), p2i(cls._cld),
129 cls._classes_count,
130 cls._chunk_sz, cls._block_sz);
131 if (class_loader_klass != nullptr) {
132 _out->print("%s", class_loader_klass->external_name());
133 } else {
134 _out->print("<boot class loader>");
135 }
136 _out->cr();
137 if (cls._hidden_classes_count > 0) {
138 _out->print_cr(SPACE SPACE SPACE " %6zu %8zu %8zu + hidden classes",
139 "", "", "",
140 cls._hidden_classes_count,
141 cls._hidden_chunk_sz, cls._hidden_block_sz);
142 }
143 return true;
144 }
145
146
147 void ClassLoaderStatsClosure::print() {
148 _out->print_cr("ClassLoader" SPACE " Parent" SPACE " CLD*" SPACE " Classes ChunkSz BlockSz Type", "", "", "");
149 _stats->iterate(this);
150 _out->print("Total = %-6zu", _total_loaders);
151 _out->print(SPACE SPACE SPACE " ", "", "", "");
152 _out->print_cr("%6zu %8zu %8zu ",
153 _total_classes,
154 _total_chunk_sz,
155 _total_block_sz);
156 _out->print_cr("ChunkSz: Total size of all allocated metaspace chunks");
157 _out->print_cr("BlockSz: Total size of all allocated metaspace blocks (each chunk has several blocks)");
158 }
159
160
161 void ClassLoaderStatsClosure::addEmptyParents(oop cl) {
162 while (cl != nullptr && java_lang_ClassLoader::loader_data_acquire(cl) == nullptr) {
163 // This classloader has not loaded any classes
164 bool added = false;
165 ClassLoaderStats* cls = _stats->put_if_absent(cl, &added);
166 if (added) {
167 cls->_class_loader = cl;
168 cls->_parent = java_lang_ClassLoader::parent_no_keepalive(cl);
169 _total_loaders++;
170 }
171 assert(cls->_class_loader == cl, "Sanity");
172
173 cl = java_lang_ClassLoader::parent_no_keepalive(cl);
174 }
175 }
176
177
178 void ClassLoaderStatsVMOperation::doit() {
179 ClassLoaderStatsClosure clsc (_out);
180 ClassLoaderDataGraph::loaded_cld_do(&clsc);
181 clsc.print();
182 }
183
184
185 void ClassLoaderStatsDCmd::execute(DCmdSource source, TRAPS) {
186 ClassLoaderStatsVMOperation op(output());
187 VMThread::execute(&op);
188 }