markSweep.hpp revision 8413:92457dfb91bd 
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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
38class ReferenceProcessor;
39class DataLayout;
40class SerialOldTracer;
41class STWGCTimer;
42
43// MarkSweep takes care of global mark-compact garbage collection for a
44// GenCollectedHeap using a four-phase pointer forwarding algorithm.  All
45// generations are assumed to support marking; those that can also support
46// compaction.
47//
48// Class unloading will only occur when a full gc is invoked.
49
50// declared at end
51class PreservedMark;
52
53class MarkSweep : AllStatic {
54  //
55  // Inline closure decls
56  //
57  class FollowRootClosure: public OopsInGenClosure {
58   public:
59    virtual void do_oop(oop* p);
60    virtual void do_oop(narrowOop* p);
61  };
62
63  class MarkAndPushClosure: public ExtendedOopClosure {
64   public:
65    template <typename T> void do_oop_nv(T* p);
66    virtual void do_oop(oop* p);
67    virtual void do_oop(narrowOop* p);
68  };
69
70  class FollowStackClosure: public VoidClosure {
71   public:
72    virtual void do_void();
73  };
74
75  class AdjustPointerClosure: public OopsInGenClosure {
76   public:
77    template <typename T> void do_oop_nv(T* p);
78    virtual void do_oop(oop* p);
79    virtual void do_oop(narrowOop* p);
80
81    // This closure provides its own oop verification code.
82    debug_only(virtual bool should_verify_oops() { return false; })
83  };
84
85  // Used for java/lang/ref handling
86  class IsAliveClosure: public BoolObjectClosure {
87   public:
88    virtual bool do_object_b(oop p);
89  };
90
91  class KeepAliveClosure: public OopClosure {
92   protected:
93    template <class T> void do_oop_work(T* p);
94   public:
95    virtual void do_oop(oop* p);
96    virtual void do_oop(narrowOop* p);
97  };
98
99  //
100  // Friend decls
101  //
102  friend class AdjustPointerClosure;
103  friend class KeepAliveClosure;
104  friend class VM_MarkSweep;
105  friend void marksweep_init();
106
107  //
108  // Vars
109  //
110 protected:
111  // Total invocations of a MarkSweep collection
112  static uint _total_invocations;
113
114  // Traversal stacks used during phase1
115  static Stack<oop, mtGC>                      _marking_stack;
116  static Stack<ObjArrayTask, mtGC>             _objarray_stack;
117
118  // Space for storing/restoring mark word
119  static Stack<markOop, mtGC>                  _preserved_mark_stack;
120  static Stack<oop, mtGC>                      _preserved_oop_stack;
121  static size_t                          _preserved_count;
122  static size_t                          _preserved_count_max;
123  static PreservedMark*                  _preserved_marks;
124
125  // Reference processing (used in ...follow_contents)
126  static ReferenceProcessor*             _ref_processor;
127
128  static STWGCTimer*                     _gc_timer;
129  static SerialOldTracer*                _gc_tracer;
130
131  // Non public closures
132  static KeepAliveClosure keep_alive;
133
134 public:
135  // Public closures
136  static IsAliveClosure       is_alive;
137  static FollowRootClosure    follow_root_closure;
138  static MarkAndPushClosure   mark_and_push_closure;
139  static FollowStackClosure   follow_stack_closure;
140  static CLDToOopClosure      follow_cld_closure;
141  static AdjustPointerClosure adjust_pointer_closure;
142  static CLDToOopClosure      adjust_cld_closure;
143
144  // Accessors
145  static uint total_invocations() { return _total_invocations; }
146
147  // Reference Processing
148  static ReferenceProcessor* const ref_processor() { return _ref_processor; }
149
150  static STWGCTimer* gc_timer() { return _gc_timer; }
151  static SerialOldTracer* gc_tracer() { return _gc_tracer; }
152
153  // Call backs for marking
154  static void mark_object(oop obj);
155  // Mark pointer and follow contents.  Empty marking stack afterwards.
156  template <class T> static inline void follow_root(T* p);
157
158  // Check mark and maybe push on marking stack
159  template <class T> static void mark_and_push(T* p);
160
161  static inline void push_objarray(oop obj, size_t index);
162
163  static void follow_stack();   // Empty marking stack.
164
165  static void follow_object(oop obj);
166
167  static void follow_array(objArrayOop array, int index);
168
169  static void follow_klass(Klass* klass);
170
171  static void follow_class_loader(ClassLoaderData* cld);
172
173  static int adjust_pointers(oop obj);
174
175  static void preserve_mark(oop p, markOop mark);
176                                // Save the mark word so it can be restored later
177  static void adjust_marks();   // Adjust the pointers in the preserved marks table
178  static void restore_marks();  // Restore the marks that we saved in preserve_mark
179
180  template <class T> static inline void adjust_pointer(T* p);
181};
182
183class PreservedMark VALUE_OBJ_CLASS_SPEC {
184private:
185  oop _obj;
186  markOop _mark;
187
188public:
189  void init(oop obj, markOop mark) {
190    _obj = obj;
191    _mark = mark;
192  }
193
194  void adjust_pointer();
195  void restore();
196};
197
198#endif // SHARE_VM_GC_SERIAL_MARKSWEEP_HPP
199