1 /* 2 * Copyright (c) 2002, 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_PARALLELSCAVENGE_PSSCAVENGE_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_HPP 27 28 #include "gc_implementation/parallelScavenge/cardTableExtension.hpp" 29 #include "gc_implementation/parallelScavenge/psVirtualspace.hpp" 30 #include "gc_implementation/shared/collectorCounters.hpp" 31 #include "gc_implementation/shared/gcTrace.hpp" 32 #include "memory/allocation.hpp" 33 #include "oops/oop.hpp" 34 #include "utilities/stack.hpp" 35 36 class GCTaskManager; 37 class GCTaskQueue; 38 class OopStack; 39 class ReferenceProcessor; 40 class ParallelScavengeHeap; 41 class ParallelScavengeTracer; 42 class PSIsAliveClosure; 43 class PSRefProcTaskExecutor; 44 class STWGCTimer; 45 46 class PSScavenge: AllStatic { 47 friend class PSIsAliveClosure; 48 friend class PSKeepAliveClosure; 49 friend class PSPromotionManager; 50 51 enum ScavengeSkippedCause { 52 not_skipped = 0, 53 to_space_not_empty, 54 promoted_too_large, 55 full_follows_scavenge 56 }; 57 58 // Saved value of to_space->top(), used to prevent objects in to_space from 59 // being rescanned. 60 static HeapWord* _to_space_top_before_gc; 61 62 // Number of consecutive attempts to scavenge that were skipped 63 static int _consecutive_skipped_scavenges; 64 65 66 protected: 67 // Flags/counters 68 static ReferenceProcessor* _ref_processor; // Reference processor for scavenging. 69 static PSIsAliveClosure _is_alive_closure; // Closure used for reference processing 70 static CardTableExtension* _card_table; // We cache the card table for fast access. 71 static bool _survivor_overflow; // Overflow this collection 72 static uint _tenuring_threshold; // tenuring threshold for next scavenge 73 static elapsedTimer _accumulated_time; // total time spent on scavenge 74 static STWGCTimer _gc_timer; // GC time book keeper 75 static ParallelScavengeTracer _gc_tracer; // GC tracing 76 // The lowest address possible for the young_gen. 77 // This is used to decide if an oop should be scavenged, 78 // cards should be marked, etc. 79 static HeapWord* _young_generation_boundary; 80 // Used to optimize compressed oops young gen boundary checking. 81 static uintptr_t _young_generation_boundary_compressed; 82 static Stack<markOop, mtGC> _preserved_mark_stack; // List of marks to be restored after failed promotion 83 static Stack<oop, mtGC> _preserved_oop_stack; // List of oops that need their mark restored. 84 static CollectorCounters* _counters; // collector performance counters 85 86 static void clean_up_failed_promotion(); 87 88 static bool should_attempt_scavenge(); 89 90 static HeapWord* to_space_top_before_gc() { return _to_space_top_before_gc; } 91 static inline void save_to_space_top_before_gc(); 92 93 // Private accessors 94 static CardTableExtension* const card_table() { assert(_card_table != NULL, "Sanity"); return _card_table; } 95 static const ParallelScavengeTracer* gc_tracer() { return &_gc_tracer; } 96 97 public: 98 // Accessors 99 static uint tenuring_threshold() { return _tenuring_threshold; } 100 static elapsedTimer* accumulated_time() { return &_accumulated_time; } 101 static int consecutive_skipped_scavenges() 102 { return _consecutive_skipped_scavenges; } 103 104 // Performance Counters 105 static CollectorCounters* counters() { return _counters; } 106 107 // Used by scavenge_contents && psMarkSweep 108 static ReferenceProcessor* const reference_processor() { 109 assert(_ref_processor != NULL, "Sanity"); 110 return _ref_processor; 111 } 112 // Used to add tasks 113 static GCTaskManager* const gc_task_manager(); 114 // The promotion managers tell us if they encountered overflow 115 static void set_survivor_overflow(bool state) { 116 _survivor_overflow = state; 117 } 118 // Adaptive size policy support. When the young generation/old generation 119 // boundary moves, _young_generation_boundary must be reset 120 static void set_young_generation_boundary(HeapWord* v) { 121 _young_generation_boundary = v; 122 if (UseCompressedOops) { 123 _young_generation_boundary_compressed = (uintptr_t)oopDesc::encode_heap_oop((oop)v); 124 } 125 } 126 127 // Called by parallelScavengeHeap to init the tenuring threshold 128 static void initialize(); 129 130 // Scavenge entry point. This may invoke a full gc; return true if so. 131 static bool invoke(); 132 // Return true if a collection was done; false otherwise. 133 static bool invoke_no_policy(); 134 135 // If an attempt to promote fails, this method is invoked 136 static void oop_promotion_failed(oop obj, markOop obj_mark); 137 138 template <class T> static inline bool should_scavenge(T* p); 139 140 // These call should_scavenge() above and, if it returns true, also check that 141 // the object was not newly copied into to_space. The version with the bool 142 // argument is a convenience wrapper that fetches the to_space pointer from 143 // the heap and calls the other version (if the arg is true). 144 template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space); 145 template <class T> static inline bool should_scavenge(T* p, bool check_to_space); 146 147 static void copy_and_push_safe_barrier_from_klass(PSPromotionManager* pm, oop* p); 148 149 // Is an object in the young generation 150 // This assumes that the 'o' is in the heap, 151 // so it only checks one side of the complete predicate. 152 153 inline static bool is_obj_in_young(oop o) { 154 return (HeapWord*)o >= _young_generation_boundary; 155 } 156 157 inline static bool is_obj_in_young(narrowOop o) { 158 return (uintptr_t)o >= _young_generation_boundary_compressed; 159 } 160 161 inline static bool is_obj_in_young(HeapWord* o) { 162 return o >= _young_generation_boundary; 163 } 164 }; 165 166 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_HPP