30 // A G1RemSet provides ways of iterating over pointers into a selected
31 // collection set.
32
33 class G1CollectedHeap;
34 class ConcurrentG1Refine;
35 class G1ParPushHeapRSClosure;
36
37 // A G1RemSet in which each heap region has a rem set that records the
38 // external heap references into it. Uses a mod ref bs to track updates,
39 // so that they can be used to update the individual region remsets.
40
41 class G1RemSet: public CHeapObj<mtGC> {
42 private:
43 G1RemSetSummary _prev_period_summary;
44 protected:
45 G1CollectedHeap* _g1;
46 size_t _conc_refine_cards;
47 uint n_workers();
48
49 protected:
50 enum SomePrivateConstants {
51 UpdateRStoMergeSync = 0,
52 MergeRStoDoDirtySync = 1,
53 DoDirtySync = 2,
54 LastSync = 3,
55
56 SeqTask = 0,
57 NumSeqTasks = 1
58 };
59
60 CardTableModRefBS* _ct_bs;
61 G1CollectorPolicy* _g1p;
62
63 ConcurrentG1Refine* _cg1r;
64
65 // Used for caching the closure that is responsible for scanning
66 // references into the collection set.
67 G1ParPushHeapRSClosure** _cset_rs_update_cl;
68
69 // Print the given summary info
70 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
71 public:
72 // This is called to reset dual hash tables after the gc pause
73 // is finished and the initial hash table is no longer being
74 // scanned.
75 void cleanupHRRS();
76
77 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
78 ~G1RemSet();
79
99 uint worker_i);
100
101 // Prepare for and cleanup after an oops_into_collection_set_do
102 // call. Must call each of these once before and after (in sequential
103 // code) any threads call oops_into_collection_set_do. (This offers an
104 // opportunity to sequential setup and teardown of structures needed by a
105 // parallel iteration over the CS's RS.)
106 void prepare_for_oops_into_collection_set_do();
107 void cleanup_after_oops_into_collection_set_do();
108
109 size_t scanRS(G1ParPushHeapRSClosure* oc,
110 CodeBlobClosure* heap_region_codeblobs,
111 uint worker_i);
112
113 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
114
115 CardTableModRefBS* ct_bs() { return _ct_bs; }
116
117 // Record, if necessary, the fact that *p (where "p" is in region "from",
118 // which is required to be non-NULL) has changed to a new non-NULL value.
119 template <class T> void write_ref(HeapRegion* from, T* p);
120 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
121
122 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
123 // or card, respectively, such that a region or card with a corresponding
124 // 0 bit contains no part of any live object. Eliminates any remembered
125 // set entries that correspond to dead heap ranges. "worker_num" is the
126 // parallel thread id of the current thread, and "hrclaimer" is the
127 // HeapRegionClaimer that should be used.
128 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
129
130 // Refine the card corresponding to "card_ptr".
131 // If check_for_refs_into_cset is true, a true result is returned
132 // if the given card contains oops that have references into the
133 // current collection set.
134 virtual bool refine_card(jbyte* card_ptr,
135 uint worker_i,
136 bool check_for_refs_into_cset);
137
138 // Print accumulated summary info from the start of the VM.
139 virtual void print_summary_info();
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30 // A G1RemSet provides ways of iterating over pointers into a selected
31 // collection set.
32
33 class G1CollectedHeap;
34 class ConcurrentG1Refine;
35 class G1ParPushHeapRSClosure;
36
37 // A G1RemSet in which each heap region has a rem set that records the
38 // external heap references into it. Uses a mod ref bs to track updates,
39 // so that they can be used to update the individual region remsets.
40
41 class G1RemSet: public CHeapObj<mtGC> {
42 private:
43 G1RemSetSummary _prev_period_summary;
44 protected:
45 G1CollectedHeap* _g1;
46 size_t _conc_refine_cards;
47 uint n_workers();
48
49 protected:
50 CardTableModRefBS* _ct_bs;
51 G1CollectorPolicy* _g1p;
52
53 ConcurrentG1Refine* _cg1r;
54
55 // Used for caching the closure that is responsible for scanning
56 // references into the collection set.
57 G1ParPushHeapRSClosure** _cset_rs_update_cl;
58
59 // Print the given summary info
60 virtual void print_summary_info(G1RemSetSummary * summary, const char * header = NULL);
61 public:
62 // This is called to reset dual hash tables after the gc pause
63 // is finished and the initial hash table is no longer being
64 // scanned.
65 void cleanupHRRS();
66
67 G1RemSet(G1CollectedHeap* g1, CardTableModRefBS* ct_bs);
68 ~G1RemSet();
69
89 uint worker_i);
90
91 // Prepare for and cleanup after an oops_into_collection_set_do
92 // call. Must call each of these once before and after (in sequential
93 // code) any threads call oops_into_collection_set_do. (This offers an
94 // opportunity to sequential setup and teardown of structures needed by a
95 // parallel iteration over the CS's RS.)
96 void prepare_for_oops_into_collection_set_do();
97 void cleanup_after_oops_into_collection_set_do();
98
99 size_t scanRS(G1ParPushHeapRSClosure* oc,
100 CodeBlobClosure* heap_region_codeblobs,
101 uint worker_i);
102
103 void updateRS(DirtyCardQueue* into_cset_dcq, uint worker_i);
104
105 CardTableModRefBS* ct_bs() { return _ct_bs; }
106
107 // Record, if necessary, the fact that *p (where "p" is in region "from",
108 // which is required to be non-NULL) has changed to a new non-NULL value.
109 template <class T> void par_write_ref(HeapRegion* from, T* p, uint tid);
110
111 // Requires "region_bm" and "card_bm" to be bitmaps with 1 bit per region
112 // or card, respectively, such that a region or card with a corresponding
113 // 0 bit contains no part of any live object. Eliminates any remembered
114 // set entries that correspond to dead heap ranges. "worker_num" is the
115 // parallel thread id of the current thread, and "hrclaimer" is the
116 // HeapRegionClaimer that should be used.
117 void scrub(BitMap* region_bm, BitMap* card_bm, uint worker_num, HeapRegionClaimer* hrclaimer);
118
119 // Refine the card corresponding to "card_ptr".
120 // If check_for_refs_into_cset is true, a true result is returned
121 // if the given card contains oops that have references into the
122 // current collection set.
123 virtual bool refine_card(jbyte* card_ptr,
124 uint worker_i,
125 bool check_for_refs_into_cset);
126
127 // Print accumulated summary info from the start of the VM.
128 virtual void print_summary_info();
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