1 /*
2 * Copyright (c) 2001, 2015, 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_G1_G1REMSET_HPP
26 #define SHARE_VM_GC_G1_G1REMSET_HPP
27
28 #include "gc/g1/g1RemSetSummary.hpp"
29
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
70 // Invoke "blk->do_oop" on all pointers into the collection set
71 // from objects in regions outside the collection set (having
72 // invoked "blk->set_region" to set the "from" region correctly
73 // beforehand.)
74 //
75 // Apply non_heap_roots on the oops of the unmarked nmethods
76 // on the strong code roots list for each region in the
77 // collection set.
78 //
79 // The "worker_i" param is for the parallel case where the id
80 // of the worker thread calling this function can be helpful in
81 // partitioning the work to be done. It should be the same as
82 // the "i" passed to the calling thread's work(i) function.
83 // In the sequential case this param will be ignored.
84 //
85 // Returns the number of cards scanned while looking for pointers
86 // into the collection set.
87 size_t oops_into_collection_set_do(G1ParPushHeapRSClosure* blk,
88 CodeBlobClosure* heap_region_codeblobs,
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();
129
130 // Print accumulated summary info from the last time called.
131 virtual void print_periodic_summary_info(const char* header);
132
133 // Prepare remembered set for verification.
134 virtual void prepare_for_verify();
135
136 size_t conc_refine_cards() const {
137 return _conc_refine_cards;
138 }
139 };
140
141 class UpdateRSOopClosure: public ExtendedOopClosure {
142 HeapRegion* _from;
143 G1RemSet* _rs;
144 uint _worker_i;
145
146 template <class T> void do_oop_work(T* p);
147
148 public:
149 UpdateRSOopClosure(G1RemSet* rs, uint worker_i = 0) :
150 _from(NULL), _rs(rs), _worker_i(worker_i)
151 {}
152
153 void set_from(HeapRegion* from) {
154 assert(from != NULL, "from region must be non-NULL");
155 _from = from;
156 }
157
158 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
159 virtual void do_oop(oop* p) { do_oop_work(p); }
160
161 // Override: this closure is idempotent.
162 // bool idempotent() { return true; }
163 bool apply_to_weak_ref_discovered_field() { return true; }
164 };
165
166 #endif // SHARE_VM_GC_G1_G1REMSET_HPP