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/preservedMarks.inline.hpp" 30 #include "gc/shared/referenceProcessor.hpp" 31 #include "gc/shared/stringdedup/stringDedup.hpp" 32 #include "gc/shared/taskqueue.hpp" 33 #include "memory/iterator.hpp" 34 #include "oops/markWord.hpp" 35 #include "oops/oop.hpp" 36 #include "runtime/timer.hpp" 37 #include "utilities/growableArray.hpp" 38 #include "utilities/stack.hpp" 39 40 class DataLayout; 41 class SerialOldTracer; 42 class STWGCTimer; 43 44 // MarkSweep takes care of global mark-compact garbage collection for a 45 // SerialHeap using a four-phase pointer forwarding algorithm. All 46 // generations are assumed to support marking; those that can also support 47 // compaction. 48 // 49 // Class unloading will only occur when a full gc is invoked. 50 51 // declared at end 52 class PreservedMark; 53 class MarkAndPushClosure; 54 class AdjustPointerClosure; 55 56 class MarkSweep : AllStatic { 57 // 58 // Inline closure decls 59 // 60 class FollowRootClosure: public BasicOopIterateClosure { 61 public: 62 virtual void do_oop(oop* p); 63 virtual void do_oop(narrowOop* p); 64 }; 65 66 class FollowStackClosure: public VoidClosure { 67 public: 68 virtual void do_void(); 69 }; 70 71 // Used for java/lang/ref handling 72 class IsAliveClosure: public BoolObjectClosure { 73 public: 74 virtual bool do_object_b(oop p); 75 }; 76 77 class KeepAliveClosure: public OopClosure { 78 protected: 79 template <class T> void do_oop_work(T* p); 80 public: 81 virtual void do_oop(oop* p); 82 virtual void do_oop(narrowOop* p); 83 }; 84 85 // 86 // Friend decls 87 // 88 friend class AdjustPointerClosure; 89 friend class KeepAliveClosure; 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 PreservedMarksSet _preserved_overflow_stack_set; 104 static size_t _preserved_count; 105 static size_t _preserved_count_max; 106 static PreservedMark* _preserved_marks; 107 108 static AlwaysTrueClosure _always_true_closure; 109 static ReferenceProcessor* _ref_processor; 110 111 static STWGCTimer* _gc_timer; 112 static SerialOldTracer* _gc_tracer; 113 114 static StringDedup::Requests* _string_dedup_requests; 115 116 // Non public closures 117 static KeepAliveClosure keep_alive; 118 119 public: 120 static void initialize(); 121 122 // Public closures 123 static IsAliveClosure is_alive; 124 static FollowRootClosure follow_root_closure; 125 static MarkAndPushClosure mark_and_push_closure; 126 static FollowStackClosure follow_stack_closure; 127 static CLDToOopClosure follow_cld_closure; 128 static AdjustPointerClosure adjust_pointer_closure; 129 static CLDToOopClosure adjust_cld_closure; 130 131 // Accessors 132 static uint total_invocations() { return _total_invocations; } 133 134 // Reference Processing 135 static ReferenceProcessor* ref_processor() { return _ref_processor; } 136 137 static STWGCTimer* gc_timer() { return _gc_timer; } 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 size_t adjust_pointers(oop obj); 146 147 static void follow_stack(); // Empty marking stack. 148 149 template <class T> static inline void adjust_pointer(T* p); 150 151 // Check mark and maybe push on marking stack 152 template <class T> static void mark_and_push(T* p); 153 154 private: 155 // Call backs for marking 156 static void mark_object(oop obj); 157 // Mark pointer and follow contents. Empty marking stack afterwards. 158 template <class T> static inline void follow_root(T* p); 159 160 static inline void push_objarray(oop obj, size_t index); 161 162 static void follow_object(oop obj); 163 164 static void follow_array(objArrayOop array); 165 166 static void follow_array_chunk(objArrayOop array, int index); 167 }; 168 169 class MarkAndPushClosure: public ClaimMetadataVisitingOopIterateClosure { 170 public: 171 MarkAndPushClosure(int claim) : ClaimMetadataVisitingOopIterateClosure(claim) {} 172 173 template <typename T> void do_oop_work(T* p); 174 virtual void do_oop( oop* p); 175 virtual void do_oop(narrowOop* p); 176 177 void set_ref_discoverer(ReferenceDiscoverer* rd) { 178 set_ref_discoverer_internal(rd); 179 } 180 }; 181 182 class AdjustPointerClosure: public BasicOopIterateClosure { 183 public: 184 template <typename T> void do_oop_work(T* p); 185 virtual void do_oop(oop* p); 186 virtual void do_oop(narrowOop* p); 187 virtual ReferenceIterationMode reference_iteration_mode() { return DO_FIELDS; } 188 }; 189 190 #endif // SHARE_GC_SERIAL_MARKSWEEP_HPP