1 /*
2 * Copyright (c) 2018, 2019, 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 *
39 friend class ClassLoaderDataGraphKlassIteratorStatic;
40 friend class ClassLoaderDataGraphIterator;
41 friend class VMStructs;
42 private:
43 // All CLDs (except the null CLD) can be reached by walking _head->_next->...
44 static ClassLoaderData* volatile _head;
45 static ClassLoaderData* _unloading;
46
47 // Set if there's anything to purge in the deallocate lists or previous versions
48 // during a safepoint after class unloading in a full GC.
49 static bool _should_clean_deallocate_lists;
50 static bool _safepoint_cleanup_needed;
51
52 // OOM has been seen in metaspace allocation. Used to prevent some
53 // allocations until class unloading
54 static bool _metaspace_oom;
55
56 static volatile size_t _num_instance_classes;
57 static volatile size_t _num_array_classes;
58
59 static ClassLoaderData* add_to_graph(Handle class_loader, bool is_unsafe_anonymous);
60 static ClassLoaderData* add(Handle class_loader, bool is_unsafe_anonymous);
61
62 public:
63 static ClassLoaderData* find_or_create(Handle class_loader);
64 static void clean_module_and_package_info();
65 static void purge();
66 static void clear_claimed_marks();
67 static void clear_claimed_marks(int claim);
68 // Iteration through CLDG inside a safepoint; GC support
69 static void cld_do(CLDClosure* cl);
70 static void cld_unloading_do(CLDClosure* cl);
71 static void roots_cld_do(CLDClosure* strong, CLDClosure* weak);
72 static void always_strong_cld_do(CLDClosure* cl);
73 // Iteration through CLDG not by GC.
74 static void loaded_cld_do(CLDClosure* cl);
75 // klass do
76 // Walking classes through the ClassLoaderDataGraph include array classes. It also includes
77 // classes that are allocated but not loaded, classes that have errors, and scratch classes
78 // for redefinition. These classes are removed during the next class unloading.
79 // Walking the ClassLoaderDataGraph also includes unsafe anonymous classes.
80 static void classes_do(KlassClosure* klass_closure);
81 static void classes_do(void f(Klass* const));
82 static void methods_do(void f(Method*));
83 static void modules_do(void f(ModuleEntry*));
84 static void modules_unloading_do(void f(ModuleEntry*));
85 static void packages_do(void f(PackageEntry*));
86 static void packages_unloading_do(void f(PackageEntry*));
87 static void loaded_classes_do(KlassClosure* klass_closure);
88 static void unlocked_loaded_classes_do(KlassClosure* klass_closure);
89 static void classes_unloading_do(void f(Klass* const));
90 static bool do_unloading();
91
92 // Expose state to avoid logging overhead in safepoint cleanup tasks.
93 static inline bool should_clean_metaspaces_and_reset();
94 static void set_should_clean_deallocate_lists() { _should_clean_deallocate_lists = true; }
95 static void clean_deallocate_lists(bool purge_previous_versions);
96 static void walk_metadata_and_clean_metaspaces();
97
98 // dictionary do
99 // Iterate over all klasses in dictionary, but
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1 /*
2 * Copyright (c) 2018, 2020, 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 *
39 friend class ClassLoaderDataGraphKlassIteratorStatic;
40 friend class ClassLoaderDataGraphIterator;
41 friend class VMStructs;
42 private:
43 // All CLDs (except the null CLD) can be reached by walking _head->_next->...
44 static ClassLoaderData* volatile _head;
45 static ClassLoaderData* _unloading;
46
47 // Set if there's anything to purge in the deallocate lists or previous versions
48 // during a safepoint after class unloading in a full GC.
49 static bool _should_clean_deallocate_lists;
50 static bool _safepoint_cleanup_needed;
51
52 // OOM has been seen in metaspace allocation. Used to prevent some
53 // allocations until class unloading
54 static bool _metaspace_oom;
55
56 static volatile size_t _num_instance_classes;
57 static volatile size_t _num_array_classes;
58
59 static ClassLoaderData* add_to_graph(Handle class_loader, bool has_class_mirror_holder);
60 static ClassLoaderData* add(Handle class_loader, bool has_class_mirror_holder);
61
62 public:
63 static ClassLoaderData* find_or_create(Handle class_loader);
64 static void clean_module_and_package_info();
65 static void purge();
66 static void clear_claimed_marks();
67 static void clear_claimed_marks(int claim);
68 // Iteration through CLDG inside a safepoint; GC support
69 static void cld_do(CLDClosure* cl);
70 static void cld_unloading_do(CLDClosure* cl);
71 static void roots_cld_do(CLDClosure* strong, CLDClosure* weak);
72 static void always_strong_cld_do(CLDClosure* cl);
73 // Iteration through CLDG not by GC.
74 static void loaded_cld_do(CLDClosure* cl);
75 // klass do
76 // Walking classes through the ClassLoaderDataGraph include array classes. It also includes
77 // classes that are allocated but not loaded, classes that have errors, and scratch classes
78 // for redefinition. These classes are removed during the next class unloading.
79 // Walking the ClassLoaderDataGraph also includes hidden and unsafe anonymous classes.
80 static void classes_do(KlassClosure* klass_closure);
81 static void classes_do(void f(Klass* const));
82 static void methods_do(void f(Method*));
83 static void modules_do(void f(ModuleEntry*));
84 static void modules_unloading_do(void f(ModuleEntry*));
85 static void packages_do(void f(PackageEntry*));
86 static void packages_unloading_do(void f(PackageEntry*));
87 static void loaded_classes_do(KlassClosure* klass_closure);
88 static void unlocked_loaded_classes_do(KlassClosure* klass_closure);
89 static void classes_unloading_do(void f(Klass* const));
90 static bool do_unloading();
91
92 // Expose state to avoid logging overhead in safepoint cleanup tasks.
93 static inline bool should_clean_metaspaces_and_reset();
94 static void set_should_clean_deallocate_lists() { _should_clean_deallocate_lists = true; }
95 static void clean_deallocate_lists(bool purge_previous_versions);
96 static void walk_metadata_and_clean_metaspaces();
97
98 // dictionary do
99 // Iterate over all klasses in dictionary, but
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