1 /* 2 * Copyright (c) 1997, 2022, 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/referenceProcessor.hpp" 30 #include "gc/shared/stringdedup/stringDedup.hpp" 31 #include "gc/shared/taskqueue.hpp" 32 #include "memory/iterator.hpp" 33 #include "oops/markWord.hpp" 34 #include "oops/oop.hpp" 35 #include "runtime/timer.hpp" 36 #include "utilities/growableArray.hpp" 37 #include "utilities/stack.hpp" 38 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 90 // 91 // Vars 92 // 93 protected: 94 // Total invocations of a MarkSweep collection 95 static uint _total_invocations; 96 97 // Traversal stacks used during phase1 98 static Stack<oop, mtGC> _marking_stack; 99 static Stack<ObjArrayTask, mtGC> _objarray_stack; 100 101 // Space for storing/restoring mark word 102 static Stack<PreservedMark, mtGC> _preserved_overflow_stack; 103 static size_t _preserved_count; 104 static size_t _preserved_count_max; 105 static PreservedMark* _preserved_marks; 106 107 static AlwaysTrueClosure _always_true_closure; 108 static ReferenceProcessor* _ref_processor; 109 110 static STWGCTimer* _gc_timer; 111 static SerialOldTracer* _gc_tracer; 112 113 static StringDedup::Requests* _string_dedup_requests; 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 131 static uint total_invocations() { return _total_invocations; } 132 133 // Reference Processing 134 static ReferenceProcessor* const ref_processor() { return _ref_processor; } 135 136 static STWGCTimer* gc_timer() { return _gc_timer; } 137 static SerialOldTracer* gc_tracer() { return _gc_tracer; } 138 139 static void preserve_mark(oop p, markWord mark); 140 // Save the mark word so it can be restored later 141 static void adjust_marks(); // Adjust the pointers in the preserved marks table 142 static void restore_marks(); // Restore the marks that we saved in preserve_mark 143 144 static size_t adjust_pointers(oop obj); 145 146 static void follow_stack(); // Empty marking stack. 147 148 template <class T> static inline void adjust_pointer(T* p); 149 150 // Check mark and maybe push on marking stack 151 template <class T> static void mark_and_push(T* p); 152 153 private: 154 // Call backs for marking 155 static void mark_object(oop obj); 156 // Mark pointer and follow contents. Empty marking stack afterwards. 157 template <class T> static inline void follow_root(T* p); 158 159 static inline void push_objarray(oop obj, size_t index); 160 161 static void follow_object(oop obj); 162 163 static void follow_array(objArrayOop array); 164 165 static void follow_array_chunk(objArrayOop array, int index); 166 }; 167 168 class MarkAndPushClosure: public ClaimMetadataVisitingOopIterateClosure { 169 public: 170 MarkAndPushClosure(int claim) : ClaimMetadataVisitingOopIterateClosure(claim) {} 171 172 template <typename T> void do_oop_work(T* p); 173 virtual void do_oop( oop* p); 174 virtual void do_oop(narrowOop* p); 175 176 void set_ref_discoverer(ReferenceDiscoverer* rd) { 177 set_ref_discoverer_internal(rd); 178 } 179 }; 180 181 class AdjustPointerClosure: public BasicOopIterateClosure { 182 public: 183 template <typename T> void do_oop_work(T* p); 184 virtual void do_oop(oop* p); 185 virtual void do_oop(narrowOop* p); 186 virtual ReferenceIterationMode reference_iteration_mode() { return DO_FIELDS; } 187 }; 188 189 class PreservedMark { 190 private: 191 oop _obj; 192 markWord _mark; 193 194 public: 195 PreservedMark(oop obj, markWord mark) : _obj(obj), _mark(mark) {} 196 void adjust_pointer(); 197 void restore(); 198 }; 199 200 #endif // SHARE_GC_SERIAL_MARKSWEEP_HPP --- EOF ---