1 /*
2 * Copyright (c) 2002, 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
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23 */
24
25 #ifndef SHARE_GC_PARALLEL_PSSCAVENGE_HPP
26 #define SHARE_GC_PARALLEL_PSSCAVENGE_HPP
27
28 #include "gc/parallel/psCardTable.hpp"
29 #include "gc/parallel/psVirtualspace.hpp"
30 #include "gc/shared/collectorCounters.hpp"
31 #include "gc/shared/gcTrace.hpp"
32 #include "memory/allocation.hpp"
33 #include "oops/oop.hpp"
34 #include "utilities/stack.hpp"
35
36 class OopStack;
37 class ReferenceProcessor;
38 class ParallelScavengeHeap;
39 class ParallelScavengeTracer;
40 class PSIsAliveClosure;
41 class PSRefProcTaskExecutor;
42 class STWGCTimer;
43
44 class PSScavenge: AllStatic {
45 friend class PSIsAliveClosure;
46 friend class PSKeepAliveClosure;
47 friend class PSPromotionManager;
48
49 enum ScavengeSkippedCause {
50 not_skipped = 0,
51 to_space_not_empty,
52 promoted_too_large,
53 full_follows_scavenge
54 };
55
56 // Saved value of to_space->top(), used to prevent objects in to_space from
57 // being rescanned.
58 static HeapWord* _to_space_top_before_gc;
59
60 // Number of consecutive attempts to scavenge that were skipped
61 static int _consecutive_skipped_scavenges;
62
63
64 protected:
65 // Flags/counters
66 static SpanSubjectToDiscoveryClosure _span_based_discoverer;
67 static ReferenceProcessor* _ref_processor; // Reference processor for scavenging.
68 static PSIsAliveClosure _is_alive_closure; // Closure used for reference processing
69 static PSCardTable* _card_table; // We cache the card table for fast access.
70 static bool _survivor_overflow; // Overflow this collection
71 static uint _tenuring_threshold; // tenuring threshold for next scavenge
72 static elapsedTimer _accumulated_time; // total time spent on scavenge
73 static STWGCTimer _gc_timer; // GC time book keeper
74 static ParallelScavengeTracer _gc_tracer; // GC tracing
75 // The lowest address possible for the young_gen.
76 // This is used to decide if an oop should be scavenged,
77 // cards should be marked, etc.
78 static HeapWord* _young_generation_boundary;
79 // Used to optimize compressed oops young gen boundary checking.
80 static uintptr_t _young_generation_boundary_compressed;
81 static CollectorCounters* _counters; // collector performance counters
82
83 static void clean_up_failed_promotion();
84
85 static bool should_attempt_scavenge();
86
87 static HeapWord* to_space_top_before_gc() { return _to_space_top_before_gc; }
88 static inline void save_to_space_top_before_gc();
89
90 // Private accessors
91 static PSCardTable* const card_table() { assert(_card_table != NULL, "Sanity"); return _card_table; }
92 static const ParallelScavengeTracer* gc_tracer() { return &_gc_tracer; }
93
94 public:
95 // Accessors
96 static uint tenuring_threshold() { return _tenuring_threshold; }
97 static elapsedTimer* accumulated_time() { return &_accumulated_time; }
98 static int consecutive_skipped_scavenges()
99 { return _consecutive_skipped_scavenges; }
100
101 // Performance Counters
102 static CollectorCounters* counters() { return _counters; }
103
104 static void set_subject_to_discovery_span(MemRegion mr) {
105 _span_based_discoverer.set_span(mr);
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 // The promotion managers tell us if they encountered overflow
113 static void set_survivor_overflow(bool state) {
114 _survivor_overflow = state;
115 }
116 // Adaptive size policy support. When the young generation/old generation
117 // boundary moves, _young_generation_boundary must be reset
118 static void set_young_generation_boundary(HeapWord* v);
119
120 // Called by parallelScavengeHeap to init the tenuring threshold
121 static void initialize();
122
123 // Scavenge entry point. This may invoke a full gc; return true if so.
124 static bool invoke();
125 // Return true if a collection was done; false otherwise.
126 static bool invoke_no_policy();
127
128 template <class T> static inline bool should_scavenge(T* p);
129
130 // These call should_scavenge() above and, if it returns true, also check that
131 // the object was not newly copied into to_space. The version with the bool
132 // argument is a convenience wrapper that fetches the to_space pointer from
133 // the heap and calls the other version (if the arg is true).
134 template <class T> static inline bool should_scavenge(T* p, MutableSpace* to_space);
135 template <class T> static inline bool should_scavenge(T* p, bool check_to_space);
136
137 static void copy_and_push_safe_barrier_from_klass(PSPromotionManager* pm, oop* p);
138
139 // Is an object in the young generation
140 // This assumes that the 'o' is in the heap,
141 // so it only checks one side of the complete predicate.
142
143 inline static bool is_obj_in_young(oop o) {
144 return (HeapWord*)o >= _young_generation_boundary;
145 }
146
147 inline static bool is_obj_in_young(narrowOop o) {
148 return (uintptr_t)o >= _young_generation_boundary_compressed;
149 }
150
151 inline static bool is_obj_in_young(HeapWord* o) {
152 return o >= _young_generation_boundary;
153 }
154 };
155
156 #endif // SHARE_GC_PARALLEL_PSSCAVENGE_HPP