1 /* 2 * Copyright (c) 1997, 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 * 23 */ 24 25 #ifndef SHARE_GC_SERIAL_MARKSWEEP_HPP 26 #define SHARE_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/markWord.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 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 51 class PreservedMark; 52 class MarkAndPushClosure; 53 class AdjustPointerClosure; 54 55 class MarkSweep : AllStatic { 56 // 57 // Inline closure decls 58 // 59 class FollowRootClosure: public BasicOopIterateClosure { 60 public: 61 virtual void do_oop(oop* p); 62 virtual void do_oop(narrowOop* p); 63 }; 64 65 class FollowStackClosure: public VoidClosure { 66 public: 67 virtual void do_void(); 68 }; 69 70 // Used for java/lang/ref handling 71 class IsAliveClosure: public BoolObjectClosure { 72 public: 73 virtual bool do_object_b(oop p); 74 }; 75 76 class KeepAliveClosure: public OopClosure { 77 protected: 78 template <class T> void do_oop_work(T* p); 79 public: 80 virtual void do_oop(oop* p); 81 virtual void do_oop(narrowOop* p); 82 }; 83 84 // 85 // Friend decls 86 // 87 friend class AdjustPointerClosure; 88 friend class KeepAliveClosure; 89 friend class VM_MarkSweep; 90 91 // 92 // Vars 93 // 94 protected: 95 // Total invocations of a MarkSweep collection 96 static uint _total_invocations; 97 98 // Traversal stacks used during phase1 99 static Stack<oop, mtGC> _marking_stack; 100 static Stack<ObjArrayTask, mtGC> _objarray_stack; 101 102 // Space for storing/restoring mark word 103 static Stack<markWord, mtGC> _preserved_mark_stack; 104 static Stack<oop, mtGC> _preserved_oop_stack; 105 static size_t _preserved_count; 106 static size_t _preserved_count_max; 107 static PreservedMark* _preserved_marks; 108 109 // Reference processing (used in ...follow_contents) 110 static ReferenceProcessor* _ref_processor; 111 112 static STWGCTimer* _gc_timer; 113 static SerialOldTracer* _gc_tracer; 114 115 // Non public closures 116 static KeepAliveClosure keep_alive; 117 118 public: 119 static void initialize(); 120 121 // Public closures 122 static IsAliveClosure is_alive; 123 static FollowRootClosure follow_root_closure; 124 static MarkAndPushClosure mark_and_push_closure; 125 static FollowStackClosure follow_stack_closure; 126 static CLDToOopClosure follow_cld_closure; 127 static AdjustPointerClosure adjust_pointer_closure; 128 static CLDToOopClosure adjust_cld_closure; 129 130 // Accessors total_invocations()131 static uint total_invocations() { return _total_invocations; } 132 133 // Reference Processing ref_processor()134 static ReferenceProcessor* const ref_processor() { return _ref_processor; } 135 static void set_ref_processor(ReferenceProcessor* rp); 136 gc_timer()137 static STWGCTimer* gc_timer() { return _gc_timer; } gc_tracer()138 static SerialOldTracer* gc_tracer() { return _gc_tracer; } 139 140 static void preserve_mark(oop p, markWord mark); 141 // Save the mark word so it can be restored later 142 static void adjust_marks(); // Adjust the pointers in the preserved marks table 143 static void restore_marks(); // Restore the marks that we saved in preserve_mark 144 145 static int adjust_pointers(oop obj); 146 147 static void follow_stack(); // Empty marking stack. 148 149 static void follow_klass(Klass* klass); 150 151 static void follow_cld(ClassLoaderData* cld); 152 153 template <class T> static inline void adjust_pointer(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 private: 159 // Call backs for marking 160 static void mark_object(oop obj); 161 // Mark pointer and follow contents. Empty marking stack afterwards. 162 template <class T> static inline void follow_root(T* p); 163 164 static inline void push_objarray(oop obj, size_t index); 165 166 static void follow_object(oop obj); 167 168 static void follow_array(objArrayOop array); 169 170 static void follow_array_chunk(objArrayOop array, int index); 171 }; 172 173 class MarkAndPushClosure: public OopIterateClosure { 174 public: 175 template <typename T> void do_oop_work(T* p); 176 virtual void do_oop(oop* p); 177 virtual void do_oop(narrowOop* p); 178 do_metadata()179 virtual bool do_metadata() { return true; } 180 virtual void do_klass(Klass* k); 181 virtual void do_cld(ClassLoaderData* cld); 182 set_ref_discoverer(ReferenceDiscoverer * rd)183 void set_ref_discoverer(ReferenceDiscoverer* rd) { 184 set_ref_discoverer_internal(rd); 185 } 186 }; 187 188 class AdjustPointerClosure: public BasicOopIterateClosure { 189 public: 190 template <typename T> void do_oop_work(T* p); 191 virtual void do_oop(oop* p); 192 virtual void do_oop(narrowOop* p); reference_iteration_mode()193 virtual ReferenceIterationMode reference_iteration_mode() { return DO_FIELDS; } 194 }; 195 196 class PreservedMark { 197 private: 198 oop _obj; 199 markWord _mark; 200 201 public: init(oop obj,markWord mark)202 void init(oop obj, markWord mark) { 203 _obj = obj; 204 _mark = mark; 205 } 206 207 void adjust_pointer(); 208 void restore(); 209 }; 210 211 #endif // SHARE_GC_SERIAL_MARKSWEEP_HPP 212