1 /*
2 * Copyright (c) 1997, 2015, 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_GC_SERIAL_MARKSWEEP_HPP
26 #define SHARE_VM_GC_SERIAL_MARKSWEEP_HPP
27
28 #include "gc/shared/collectedHeap.hpp"
29 #include "gc/shared/genOopClosures.hpp"
30 #include "gc/shared/taskqueue.hpp"
31 #include "memory/iterator.hpp"
32 #include "oops/markOop.hpp"
33 #include "oops/oop.hpp"
34 #include "runtime/timer.hpp"
35 #include "utilities/growableArray.hpp"
36 #include "utilities/stack.hpp"
37
38 class ReferenceProcessor;
39 class DataLayout;
40 class SerialOldTracer;
41 class STWGCTimer;
42 class MarkSweep;
43
44 class MarkAndPushClosure: public ExtendedOopClosure {
45 MarkSweep* _ms;
46 public:
47 MarkAndPushClosure(MarkSweep* ms) : _ms(ms) {}
48 template <typename T> void do_oop_nv(T* p);
49 virtual void do_oop(oop* p);
50 virtual void do_oop(narrowOop* p);
51
52 virtual bool do_metadata();
53 bool do_metadata_nv();
54
55 virtual void do_klass(Klass* k);
56 void do_klass_nv(Klass* k);
57
58 virtual void do_cld(ClassLoaderData* cld);
59 void do_cld_nv(ClassLoaderData* cld);
60
61 void set_ref_processor(ReferenceProcessor* rp) {
62 set_ref_processor_internal(rp);
63 }
64 };
65
66 // MarkSweep takes care of global mark-compact garbage collection for a
67 // GenCollectedHeap using a four-phase pointer forwarding algorithm. All
68 // generations are assumed to support marking; those that can also support
69 // compaction.
70 //
71 // Class unloading will only occur when a full gc is invoked.
72
73 // declared at end
74 class PreservedMark;
75
76 class MarkSweep : public StackObj {
77 //
78 // Inline closure decls
79 //
80 class FollowRootClosure: public OopsInGenClosure {
81 MarkSweep* _ms;
82 public:
83 FollowRootClosure(MarkSweep* ms) : _ms(ms) {}
84 virtual void do_oop(oop* p);
85 virtual void do_oop(narrowOop* p);
86 };
87
88 class FollowStackClosure: public VoidClosure {
89 MarkSweep* _ms;
90 public:
91 FollowStackClosure(MarkSweep* ms) : _ms(ms) {}
92 virtual void do_void();
93 };
94
95 class AdjustPointerClosure: public OopsInGenClosure {
96 public:
97 template <typename T> void do_oop_nv(T* p);
98 virtual void do_oop(oop* p);
99 virtual void do_oop(narrowOop* p);
100
101 // This closure provides its own oop verification code.
102 debug_only(virtual bool should_verify_oops() { return false; })
103 };
104
105 // Used for java/lang/ref handling
106 class IsAliveClosure: public BoolObjectClosure {
107 MarkSweep* _ms;
108 public:
109 IsAliveClosure(MarkSweep* ms) : _ms(ms) {}
110 virtual bool do_object_b(oop p);
111 };
112
113 class KeepAliveClosure: public OopClosure {
114 MarkSweep* _ms;
115 protected:
116 template <class T> void do_oop_work(T* p);
117 public:
118 KeepAliveClosure(MarkSweep* ms) : _ms(ms) {}
119 virtual void do_oop(oop* p);
120 virtual void do_oop(narrowOop* p);
121 };
122
123 //
124 // Friend decls
125 //
126 friend class AdjustPointerClosure;
127 friend class KeepAliveClosure;
128 friend class VM_MarkSweep;
129 friend void marksweep_init();
130
131 //
132 // Vars
133 //
134 protected:
135 // Total invocations of a MarkSweep collection
136 static uint _total_invocations;
137
138 // Traversal stacks used during phase1
139 Stack<oop, mtGC> _marking_stack;
140 Stack<ObjArrayTask, mtGC> _objarray_stack;
141
142 // Space for storing/restoring mark word
143 Stack<markOop, mtGC> _preserved_mark_stack;
144 Stack<oop, mtGC> _preserved_oop_stack;
145 size_t _preserved_count;
146 size_t _preserved_count_max;
147 PreservedMark* _preserved_marks;
148
149 // Reference processing (used in ...follow_contents)
150 ReferenceProcessor* _ref_processor;
151
152 static STWGCTimer* _gc_timer;
153 static SerialOldTracer* _gc_tracer;
154
155 // Non public closures
156 KeepAliveClosure keep_alive;
157
158 public:
159 // Constructor
160 MarkSweep();
161
162 // Destructor
163 ~MarkSweep();
164
165 // Public closures
166 IsAliveClosure is_alive;
167 FollowRootClosure follow_root_closure;
168 MarkAndPushClosure mark_and_push_closure;
169 FollowStackClosure follow_stack_closure;
170 CLDToOopClosure follow_cld_closure;
171 AdjustPointerClosure adjust_pointer_closure;
172 CLDToOopClosure adjust_cld_closure;
173
174 // Accessors
175 static uint total_invocations() { return _total_invocations; }
176
177 // Reference Processing
178 ReferenceProcessor* const ref_processor() { return _ref_processor; }
179 void set_ref_processor(ReferenceProcessor* rp);
180
181 // Archive Object handling
182 static inline bool is_archive_object(oop object);
183
184 static STWGCTimer* gc_timer() { return _gc_timer; }
185 static SerialOldTracer* gc_tracer() { return _gc_tracer; }
186
187 void preserve_mark(oop p, markOop mark);
188 // Save the mark word so it can be restored later
189 void adjust_marks(); // Adjust the pointers in the preserved marks table
190 void restore_marks(); // Restore the marks that we saved in preserve_mark
191
192 int adjust_pointers(oop obj);
193
194 void follow_stack(); // Empty marking stack.
195
196 void follow_klass(Klass* klass);
197
198 void follow_cld(ClassLoaderData* cld);
199
200 template <class T> static inline void adjust_pointer(T* p);
201
202 // Check mark and maybe push on marking stack
203 template <class T> void mark_and_push(T* p);
204
205 private:
206 // Call backs for marking
207 void mark_object(oop obj);
208 // Mark pointer and follow contents. Empty marking stack afterwards.
209 template <class T> inline void follow_root(T* p);
210
211 inline void push_objarray(oop obj, size_t index);
212
213 void follow_object(oop obj);
214
215 void follow_array(objArrayOop array);
216
217 void follow_array_chunk(objArrayOop array, int index);
218 };
219
220 class PreservedMark VALUE_OBJ_CLASS_SPEC {
221 private:
222 oop _obj;
223 markOop _mark;
224
225 public:
226 void init(oop obj, markOop mark) {
227 _obj = obj;
228 _mark = mark;
229 }
230
231 void adjust_pointer();
232 void restore();
233 };
234
235 #endif // SHARE_VM_GC_SERIAL_MARKSWEEP_HPP