1 /*
2 * Copyright (c) 2013, 2015, Red Hat, Inc. and/or its affiliates.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_HPP
25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_HPP
26
27 #include "utilities/taskqueue.hpp"
28 #include "utilities/workgroup.hpp"
29 #include "gc_implementation/shenandoah/shenandoahTaskqueue.hpp"
30 #include "gc_implementation/shenandoah/shenandoahPhaseTimings.hpp"
31
32 class ShenandoahStrDedupQueue;
33
34 class ShenandoahConcurrentMark: public CHeapObj<mtGC> {
35
36 private:
37 ShenandoahHeap* _heap;
38
39 // The per-worker-thread work queues
40 ShenandoahObjToScanQueueSet* _task_queues;
41
42 ShenandoahSharedFlag _claimed_codecache;
43
44 // Used for buffering per-region liveness data.
45 // Needed since ShenandoahHeapRegion uses atomics to update liveness.
46 //
47 // The array has max-workers elements, each of which is an array of
48 // jushort * max_regions. The choice of jushort is not accidental:
49 // there is a tradeoff between static/dynamic footprint that translates
50 // into cache pressure (which is already high during marking), and
51 // too many atomic updates. size_t/jint is too large, jbyte is too small.
52 jushort** _liveness_local;
53
54 private:
55 template <class T>
56 inline void do_task(ShenandoahObjToScanQueue* q, T* cl, jushort* live_data, ShenandoahMarkTask* task);
57
58 template <class T>
59 inline void do_chunked_array_start(ShenandoahObjToScanQueue* q, T* cl, oop array);
60
61 template <class T>
62 inline void do_chunked_array(ShenandoahObjToScanQueue* q, T* cl, oop array, int chunk, int pow);
63
64 inline void count_liveness(jushort* live_data, oop obj);
65 inline void count_liveness_humongous(oop obj);
66
67 // Actual mark loop with closures set up
68 template <class T, bool CANCELLABLE>
69 void mark_loop_work(T* cl, jushort* live_data, uint worker_id, ParallelTaskTerminator *t);
70
71 template <bool CANCELLABLE>
72 void mark_loop_prework(uint worker_id, ParallelTaskTerminator *terminator, ReferenceProcessor *rp,
73 bool class_unload, bool update_refs, bool strdedup);
74
75 public:
76 // Mark loop entry.
77 // Translates dynamic arguments to template parameters with progressive currying.
78 void mark_loop(uint worker_id, ParallelTaskTerminator* terminator, ReferenceProcessor *rp,
79 bool cancellable,
80 bool class_unload, bool update_refs, bool strdedup) {
81 if (cancellable) {
82 mark_loop_prework<true>(worker_id, terminator, rp, class_unload, update_refs, strdedup);
83 } else {
84 mark_loop_prework<false>(worker_id, terminator, rp, class_unload, update_refs, strdedup);
85 }
86 }
87
88 // We need to do this later when the heap is already created.
89 void initialize(uint workers);
90
91 bool process_references() const;
92 bool unload_classes() const;
93
94 bool claim_codecache();
95 void clear_claim_codecache();
96
97 template<class T, UpdateRefsMode UPDATE_REFS>
98 static inline void mark_through_ref(T* p, ShenandoahHeap* heap, ShenandoahObjToScanQueue* q, ShenandoahMarkingContext* const mark_context);
99
100 template<class T, UpdateRefsMode UPDATE_REFS, bool STRING_DEDUP>
101 static inline void mark_through_ref(T* p, ShenandoahHeap* heap, ShenandoahObjToScanQueue* q, ShenandoahMarkingContext* const mark_context, ShenandoahStrDedupQueue* dq = NULL);
102
103 void mark_from_roots();
104
105 // Prepares unmarked root objects by marking them and putting
106 // them into the marking task queue.
107 void init_mark_roots();
108 void mark_roots(ShenandoahPhaseTimings::Phase root_phase);
109 void update_roots(ShenandoahPhaseTimings::Phase root_phase);
110
111 void shared_finish_mark_from_roots(bool full_gc);
112 void finish_mark_from_roots();
113 // Those are only needed public because they're called from closures.
114
115 inline bool try_queue(ShenandoahObjToScanQueue* q, ShenandoahMarkTask &task);
116
117 ShenandoahObjToScanQueue* get_queue(uint worker_id);
118 void clear_queue(ShenandoahObjToScanQueue *q);
119
120 ShenandoahObjToScanQueueSet* task_queues() { return _task_queues;}
121
122 jushort* get_liveness(uint worker_id);
123
124 void cancel();
125
126 void preclean_weak_refs();
127
128 void concurrent_scan_code_roots(uint worker_id, ReferenceProcessor* rp, bool update_ref);
129 private:
130
131 void weak_refs_work(bool full_gc);
132 void weak_refs_work_doit(bool full_gc);
133 };
134
135 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHCONCURRENTMARK_HPP