1 /*
2 * Copyright (c) 2002, 2012, 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 "memory/allocation.hpp"
32 #include "oops/oop.hpp"
33 #include "utilities/stack.hpp"
34
35 class GCTaskManager;
36 class GCTaskQueue;
37 class OopStack;
38 class ReferenceProcessor;
39 class ParallelScavengeHeap;
40 class PSIsAliveClosure;
41 class PSRefProcTaskExecutor;
42
43 class PSScavenge: AllStatic {
44 friend class PSIsAliveClosure;
45 friend class PSKeepAliveClosure;
46 friend class PSPromotionManager;
47
48 enum ScavengeSkippedCause {
49 not_skipped = 0,
50 to_space_not_empty,
51 promoted_too_large,
52 full_follows_scavenge
53 };
54
55 // Saved value of to_space->top(), used to prevent objects in to_space from
56 // being rescanned.
57 static HeapWord* _to_space_top_before_gc;
58
59 // Number of consecutive attempts to scavenge that were skipped
60 static int _consecutive_skipped_scavenges;
61
62
63 protected:
64 // Flags/counters
65 static ReferenceProcessor* _ref_processor; // Reference processor for scavenging.
66 static PSIsAliveClosure _is_alive_closure; // Closure used for reference processing
67 static CardTableExtension* _card_table; // We cache the card table for fast access.
68 static bool _survivor_overflow; // Overflow this collection
69 static uint _tenuring_threshold; // tenuring threshold for next scavenge
70 static elapsedTimer _accumulated_time; // total time spent on scavenge
71 // The lowest address possible for the young_gen.
72 // This is used to decide if an oop should be scavenged,
73 // cards should be marked, etc.
74 static HeapWord* _young_generation_boundary;
75 // Used to optimize compressed oops young gen boundary checking.
76 static uintptr_t _young_generation_boundary_compressed;
77 static Stack<markOop, mtGC> _preserved_mark_stack; // List of marks to be restored after failed promotion
78 static Stack<oop, mtGC> _preserved_oop_stack; // List of oops that need their mark restored.
79 static CollectorCounters* _counters; // collector performance counters
80 static bool _promotion_failed;
81
82 static void clean_up_failed_promotion();
83
84 static bool should_attempt_scavenge();
85
86 static HeapWord* to_space_top_before_gc() { return _to_space_top_before_gc; }
87 static inline void save_to_space_top_before_gc();
88
89 // Private accessors
90 static CardTableExtension* const card_table() { assert(_card_table != NULL, "Sanity"); return _card_table; }
91
92 public:
93 // Accessors
94 static uint tenuring_threshold() { return _tenuring_threshold; }
95 static elapsedTimer* accumulated_time() { return &_accumulated_time; }
96 static bool promotion_failed() { return _promotion_failed; }
97 static int consecutive_skipped_scavenges()
98 { return _consecutive_skipped_scavenges; }
99
100 // Performance Counters
101 static CollectorCounters* counters() { return _counters; }
102
103 // Used by scavenge_contents && psMarkSweep
104 static ReferenceProcessor* const reference_processor() {
105 assert(_ref_processor != NULL, "Sanity");
106 return _ref_processor;
107 }
108 // Used to add tasks
109 static GCTaskManager* const gc_task_manager();
110 // The promotion managers tell us if they encountered overflow
111 static void set_survivor_overflow(bool state) {
112 _survivor_overflow = state;
113 }
114 // Adaptive size policy support. When the young generation/old generation
115 // boundary moves, _young_generation_boundary must be reset
116 static void set_young_generation_boundary(HeapWord* v) {
117 _young_generation_boundary = v;
118 if (UseCompressedOops) {
119 _young_generation_boundary_compressed = (uintptr_t)oopDesc::encode_heap_oop((oop)v);
120 }
121 }
122
123 // Called by parallelScavengeHeap to init the tenuring threshold
124 static void initialize();
125
126 // Scavenge entry point. This may invoke a full gc; return true if so.
127 static bool invoke();
128 // Return true if a collection was done; false otherwise.
129 static bool invoke_no_policy();
130
131 // If an attempt to promote fails, this method is invoked
132 static void oop_promotion_failed(oop obj, markOop obj_mark);
133
134 template <class T> static inline bool should_scavenge(T* p);
135
136 // These call should_scavenge() above and, if it returns true, also check that
137 // the object was not newly copied into to_space. The version with the bool
138 // argument is a convenience wrapper that fetches the to_space pointer from
139 // the heap and calls the other version (if the arg is true).
140 template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space);
141 template <class T> static inline bool should_scavenge(T* p, bool check_to_space);
142
143 template <class T, bool promote_immediately>
144 inline static void copy_and_push_safe_barrier(PSPromotionManager* pm, T* p);
145
146 static void copy_and_push_safe_barrier_from_klass(PSPromotionManager* pm, oop* p);
147
148 // Is an object in the young generation
149 // This assumes that the 'o' is in the heap,
150 // so it only checks one side of the complete predicate.
151
152 inline static bool is_obj_in_young(oop o) {
153 return (HeapWord*)o >= _young_generation_boundary;
154 }
155
156 inline static bool is_obj_in_young(narrowOop o) {
157 return (uintptr_t)o >= _young_generation_boundary_compressed;
158 }
159
160 inline static bool is_obj_in_young(HeapWord* o) {
161 return o >= _young_generation_boundary;
162 }
163 };
164
165 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSSCAVENGE_HPP