1 /* 2 * Copyright (c) 1997, 2013, 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_IMPLEMENTATION_SHARED_MARKSWEEP_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_SHARED_MARKSWEEP_HPP 27 28 #include "gc_interface/collectedHeap.hpp" 29 #include "memory/universe.hpp" 30 #include "oops/markOop.hpp" 31 #include "oops/oop.hpp" 32 #include "runtime/timer.hpp" 33 #include "utilities/growableArray.hpp" 34 #include "utilities/stack.hpp" 35 #include "utilities/taskqueue.hpp" 36 37 class ReferenceProcessor; 38 class DataLayout; 39 class SerialOldTracer; 40 class STWGCTimer; 41 42 // MarkSweep takes care of global mark-compact garbage collection for a 43 // GenCollectedHeap using a four-phase pointer forwarding algorithm. All 44 // generations are assumed to support marking; those that can also support 45 // compaction. 46 // 47 // Class unloading will only occur when a full gc is invoked. 48 49 // declared at end 50 class PreservedMark; 51 52 class MarkSweep : AllStatic { 53 // 54 // Inline closure decls 55 // 56 class FollowRootClosure: public OopsInGenClosure { 57 public: 58 virtual void do_oop(oop* p); 59 virtual void do_oop(narrowOop* p); 60 }; 61 62 class MarkAndPushClosure: public OopClosure { 63 public: 64 virtual void do_oop(oop* p); 65 virtual void do_oop(narrowOop* p); 66 }; 67 68 class FollowStackClosure: public VoidClosure { 69 public: 70 virtual void do_void(); 71 }; 72 73 class AdjustPointerClosure: public OopsInGenClosure { 74 public: 75 virtual void do_oop(oop* p); 76 virtual void do_oop(narrowOop* p); 77 }; 78 79 // Used for java/lang/ref handling 80 class IsAliveClosure: public BoolObjectClosure { 81 public: 82 virtual bool do_object_b(oop p); 83 }; 84 85 class KeepAliveClosure: public OopClosure { 86 protected: 87 template <class T> void do_oop_work(T* p); 88 public: 89 virtual void do_oop(oop* p); 90 virtual void do_oop(narrowOop* p); 91 }; 92 93 // 94 // Friend decls 95 // 96 friend class AdjustPointerClosure; 97 friend class KeepAliveClosure; 98 friend class VM_MarkSweep; 99 friend void marksweep_init(); 100 101 // 102 // Vars 103 // 104 protected: 105 // Total invocations of a MarkSweep collection 106 static uint _total_invocations; 107 108 // Traversal stacks used during phase1 109 static Stack<oop, mtGC> _marking_stack; 110 static Stack<ObjArrayTask, mtGC> _objarray_stack; 111 112 // Space for storing/restoring mark word 113 static Stack<markOop, mtGC> _preserved_mark_stack; 114 static Stack<oop, mtGC> _preserved_oop_stack; 115 static size_t _preserved_count; 116 static size_t _preserved_count_max; 117 static PreservedMark* _preserved_marks; 118 119 // Reference processing (used in ...follow_contents) 120 static ReferenceProcessor* _ref_processor; 121 122 static STWGCTimer* _gc_timer; 123 static SerialOldTracer* _gc_tracer; 124 125 // Non public closures 126 static KeepAliveClosure keep_alive; 127 128 // Debugging 129 static void trace(const char* msg) PRODUCT_RETURN; 130 131 public: 132 // Public closures 133 static IsAliveClosure is_alive; 134 static FollowRootClosure follow_root_closure; 135 static MarkAndPushClosure mark_and_push_closure; 136 static FollowStackClosure follow_stack_closure; 137 static CLDToOopClosure follow_cld_closure; 138 static AdjustPointerClosure adjust_pointer_closure; 139 static CLDToOopClosure adjust_cld_closure; 140 141 // Accessors 142 static uint total_invocations() { return _total_invocations; } 143 144 // Reference Processing 145 static ReferenceProcessor* const ref_processor() { return _ref_processor; } 146 147 static STWGCTimer* gc_timer() { return _gc_timer; } 148 static SerialOldTracer* gc_tracer() { return _gc_tracer; } 149 150 // Call backs for marking 151 static void mark_object(oop obj); 152 // Mark pointer and follow contents. Empty marking stack afterwards. 153 template <class T> static inline void follow_root(T* p); 154 155 // Check mark and maybe push on marking stack 156 template <class T> static void mark_and_push(T* p); 157 158 static inline void push_objarray(oop obj, size_t index); 159 160 static void follow_stack(); // Empty marking stack. 161 162 static void follow_klass(Klass* klass); 163 164 static void follow_class_loader(ClassLoaderData* cld); 165 166 static void preserve_mark(oop p, markOop mark); 167 // Save the mark word so it can be restored later 168 static void adjust_marks(); // Adjust the pointers in the preserved marks table 169 static void restore_marks(); // Restore the marks that we saved in preserve_mark 170 171 template <class T> static inline void adjust_pointer(T* p); 172 }; 173 174 class PreservedMark VALUE_OBJ_CLASS_SPEC { 175 private: 176 oop _obj; 177 markOop _mark; 178 179 public: 180 void init(oop obj, markOop mark) { 181 _obj = obj; 182 _mark = mark; 183 } 184 185 void adjust_pointer() { 186 MarkSweep::adjust_pointer(&_obj); 187 } 188 189 void restore() { 190 _obj->set_mark(_mark); 191 } 192 }; 193 194 #endif // SHARE_VM_GC_IMPLEMENTATION_SHARED_MARKSWEEP_HPP