Mercurial > hg > graal-jvmci-8
comparison src/share/vm/classfile/classLoaderData.hpp @ 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 |
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date | Sat, 01 Sep 2012 13:25:18 -0400 |
parents | |
children | e861d44e0c9c |
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1 /* | |
2 * Copyright (c) 2012, 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 #ifndef SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP | |
26 #define SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP | |
27 | |
28 #include "memory/allocation.hpp" | |
29 #include "memory/memRegion.hpp" | |
30 #include "memory/metaspace.hpp" | |
31 #include "memory/metaspaceCounters.hpp" | |
32 #include "runtime/mutex.hpp" | |
33 #include "utilities/growableArray.hpp" | |
34 | |
35 // | |
36 // A class loader represents a linkset. Conceptually, a linkset identifies | |
37 // the complete transitive closure of resolved links that a dynamic linker can | |
38 // produce. | |
39 // | |
40 // A ClassLoaderData also encapsulates the allocation space, called a metaspace, | |
41 // used by the dynamic linker to allocate the runtime representation of all | |
42 // the types it defines. | |
43 // | |
44 // ClassLoaderData are stored in the runtime representation of classes and the | |
45 // system dictionary, are roots of garbage collection, and provides iterators | |
46 // for root tracing and other GC operations. | |
47 | |
48 class ClassLoaderData; | |
49 class JNIMethodBlock; | |
50 class JNIHandleBlock; | |
51 class Metadebug; | |
52 // GC root for walking class loader data created | |
53 | |
54 class ClassLoaderDataGraph : public AllStatic { | |
55 friend class ClassLoaderData; | |
56 friend class ClassLoaderDataGraphMetaspaceIterator; | |
57 friend class VMStructs; | |
58 private: | |
59 // All CLDs (except the null CLD) can be reached by walking _head->_next->... | |
60 static ClassLoaderData* _head; | |
61 static ClassLoaderData* _unloading; | |
62 // CMS support. | |
63 static ClassLoaderData* _saved_head; | |
64 | |
65 static ClassLoaderData* add(ClassLoaderData** loader_data_addr, Handle class_loader); | |
66 public: | |
67 static ClassLoaderData* find_or_create(Handle class_loader); | |
68 static void purge(); | |
69 static void clear_claimed_marks(); | |
70 static void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim); | |
71 static void always_strong_oops_do(OopClosure* blk, KlassClosure* klass_closure, bool must_claim); | |
72 static void classes_do(KlassClosure* klass_closure); | |
73 static bool do_unloading(BoolObjectClosure* is_alive); | |
74 | |
75 // CMS support. | |
76 static void remember_new_clds(bool remember) { _saved_head = (remember ? _head : NULL); } | |
77 static GrowableArray<ClassLoaderData*>* new_clds(); | |
78 | |
79 static void dump_on(outputStream * const out) PRODUCT_RETURN; | |
80 static void dump() { dump_on(tty); } | |
81 static void verify(); | |
82 | |
83 #ifndef PRODUCT | |
84 // expensive test for pointer in metaspace for debugging | |
85 static bool contains(address x); | |
86 static bool contains_loader_data(ClassLoaderData* loader_data); | |
87 #endif | |
88 }; | |
89 | |
90 // ClassLoaderData class | |
91 | |
92 class ClassLoaderData : public CHeapObj<mtClass> { | |
93 friend class VMStructs; | |
94 private: | |
95 friend class ClassLoaderDataGraph; | |
96 friend class ClassLoaderDataGraphMetaspaceIterator; | |
97 friend class MetaDataFactory; | |
98 friend class Method; | |
99 | |
100 static ClassLoaderData * _the_null_class_loader_data; | |
101 | |
102 oop _class_loader; // oop used to uniquely identify a class loader | |
103 // class loader or a canonical class path | |
104 Metaspace * _metaspace; // Meta-space where meta-data defined by the | |
105 // classes in the class loader are allocated. | |
106 Mutex* _metaspace_lock; // Locks the metaspace for allocations and setup. | |
107 bool _unloading; // true if this class loader goes away | |
108 volatile int _claimed; // true if claimed, for example during GC traces. | |
109 // To avoid applying oop closure more than once. | |
110 // Has to be an int because we cas it. | |
111 Klass* _klasses; // The classes defined by the class loader. | |
112 | |
113 JNIHandleBlock* _handles; // Handles to constant pool arrays | |
114 | |
115 // These method IDs are created for the class loader and set to NULL when the | |
116 // class loader is unloaded. They are rarely freed, only for redefine classes | |
117 // and if they lose a data race in InstanceKlass. | |
118 JNIMethodBlock* _jmethod_ids; | |
119 | |
120 // Metadata to be deallocated when it's safe at class unloading, when | |
121 // this class loader isn't unloaded itself. | |
122 GrowableArray<Metadata*>* _deallocate_list; | |
123 | |
124 // Support for walking class loader data objects | |
125 ClassLoaderData* _next; /// Next loader_datas created | |
126 | |
127 // ReadOnly and ReadWrite metaspaces (static because only on the null | |
128 // class loader for now). | |
129 static Metaspace* _ro_metaspace; | |
130 static Metaspace* _rw_metaspace; | |
131 | |
132 bool has_dependency(ClassLoaderData* cld); | |
133 void add_dependency(ClassLoaderData* to_loader_data, TRAPS); | |
134 | |
135 void set_next(ClassLoaderData* next) { _next = next; } | |
136 ClassLoaderData* next() const { return _next; } | |
137 | |
138 ClassLoaderData(Handle h_class_loader); | |
139 ~ClassLoaderData(); | |
140 | |
141 void set_metaspace(Metaspace* m) { _metaspace = m; } | |
142 | |
143 JNIHandleBlock* handles() const; | |
144 void set_handles(JNIHandleBlock* handles); | |
145 | |
146 Mutex* metaspace_lock() const { return _metaspace_lock; } | |
147 | |
148 // GC interface. | |
149 void clear_claimed() { _claimed = 0; } | |
150 bool claimed() const { return _claimed == 1; } | |
151 bool claim(); | |
152 | |
153 void mark_for_unload() { _unloading = true; } | |
154 | |
155 void classes_do(void f(InstanceKlass*)); | |
156 | |
157 // Deallocate free list during class unloading. | |
158 void free_deallocate_list(); | |
159 | |
160 // Allocate out of this class loader data | |
161 MetaWord* allocate(size_t size); | |
162 | |
163 public: | |
164 // Accessors | |
165 Metaspace* metaspace_or_null() const { return _metaspace; } | |
166 | |
167 static ClassLoaderData* the_null_class_loader_data() { | |
168 return _the_null_class_loader_data; | |
169 } | |
170 | |
171 static void init_null_class_loader_data() { | |
172 assert(_the_null_class_loader_data == NULL, "cannot initialize twice"); | |
173 assert(ClassLoaderDataGraph::_head == NULL, "cannot initialize twice"); | |
174 _the_null_class_loader_data = new ClassLoaderData((oop)NULL); | |
175 ClassLoaderDataGraph::_head = _the_null_class_loader_data; | |
176 assert(_the_null_class_loader_data->is_the_null_class_loader_data(), "Must be"); | |
177 if (DumpSharedSpaces) { | |
178 _the_null_class_loader_data->initialize_shared_metaspaces(); | |
179 } | |
180 } | |
181 | |
182 bool is_the_null_class_loader_data() const { | |
183 return this == _the_null_class_loader_data; | |
184 } | |
185 | |
186 // The Metaspace is created lazily so may be NULL. This | |
187 // method will allocate a Metaspace if needed. | |
188 Metaspace* metaspace_non_null(); | |
189 | |
190 oop class_loader() const { return _class_loader; } | |
191 | |
192 // Returns true if this class loader data is for a loader going away. | |
193 bool is_unloading() const { | |
194 assert(!(is_the_null_class_loader_data() && _unloading), "The null class loader can never be unloaded"); | |
195 return _unloading; | |
196 } | |
197 | |
198 unsigned int identity_hash() { | |
199 return _class_loader == NULL ? 0 : _class_loader->identity_hash(); | |
200 } | |
201 | |
202 // Used when tracing from klasses. | |
203 void oops_do(OopClosure* f, KlassClosure* klass_closure, bool must_claim); | |
204 | |
205 void classes_do(KlassClosure* klass_closure); | |
206 | |
207 bool has_defined(Klass* klass) { | |
208 for (Klass* k = _klasses; k != NULL; k = k->next_link()) { | |
209 if (klass == k) { | |
210 return true; | |
211 } | |
212 } | |
213 return false; | |
214 } | |
215 | |
216 JNIMethodBlock* jmethod_ids() const { return _jmethod_ids; } | |
217 void set_jmethod_ids(JNIMethodBlock* new_block) { _jmethod_ids = new_block; } | |
218 | |
219 void print_value() { print_value_on(tty); } | |
220 void print_value_on(outputStream* out) const PRODUCT_RETURN; | |
221 void dump(outputStream * const out) PRODUCT_RETURN; | |
222 void verify(); | |
223 | |
224 jobject add_handle(Handle h); | |
225 void add_class(Klass* k); | |
226 void remove_class(Klass* k); | |
227 void record_dependency(Klass* to, TRAPS); | |
228 | |
229 void add_to_deallocate_list(Metadata* m); | |
230 | |
231 static ClassLoaderData* class_loader_data(oop loader); | |
232 static void print_loader(ClassLoaderData *loader_data, outputStream *out); | |
233 | |
234 // CDS support | |
235 Metaspace* ro_metaspace(); | |
236 Metaspace* rw_metaspace(); | |
237 void initialize_shared_metaspaces(); | |
238 }; | |
239 | |
240 class ClassLoaderDataGraphMetaspaceIterator : public StackObj { | |
241 ClassLoaderData* _data; | |
242 public: | |
243 ClassLoaderDataGraphMetaspaceIterator(); | |
244 ~ClassLoaderDataGraphMetaspaceIterator(); | |
245 bool repeat() { return _data != NULL; } | |
246 Metaspace* get_next() { | |
247 assert(_data != NULL, "Should not be NULL in call to the iterator"); | |
248 Metaspace* result = _data->metaspace_or_null(); | |
249 _data = _data->next(); | |
250 // This result might be NULL for class loaders without metaspace | |
251 // yet. It would be nice to return only non-null results but | |
252 // there is no guarantee that there will be a non-null result | |
253 // down the list so the caller is going to have to check. | |
254 return result; | |
255 } | |
256 }; | |
257 #endif // SHARE_VM_CLASSFILE_CLASSLOADERDATA_HPP |