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 }