1 /*
2 * Copyright (c) 2013, 2014, 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 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1CardCounts.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
29 #include "gc_implementation/g1/g1GCPhaseTimes.hpp"
30 #include "memory/cardTableModRefBS.hpp"
31 #include "services/memTracker.hpp"
32 #include "utilities/copy.hpp"
33
34 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
35
36 void G1CardCountsMappingChangedListener::on_commit(uint start_idx, size_t num_regions) {
37 MemRegion mr(G1CollectedHeap::heap()->bottom_addr_for_region(start_idx), num_regions * HeapRegion::GrainWords);
38 _counts->clear_range(mr);
39 }
40
41 void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
42 if (has_count_table()) {
43 assert(from_card_num < to_card_num,
44 err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,
45 from_card_num, to_card_num));
46 Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));
47 }
48 }
49
50 G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):
51 _listener(), _g1h(g1h), _card_counts(NULL), _reserved_max_card_num(0) {
52 _listener.set_cardcounts(this);
53 }
54
55 void G1CardCounts::initialize(G1RegionToSpaceMapper* mapper) {
56 assert(_g1h->max_capacity() > 0, "initialization order");
57 assert(_g1h->capacity() == 0, "initialization order");
58
59 if (G1ConcRSHotCardLimit > 0) {
60 // The max value we can store in the counts table is
61 // max_jubyte. Guarantee the value of the hot
62 // threshold limit is no more than this.
63 guarantee(G1ConcRSHotCardLimit <= max_jubyte, "sanity");
64
65 _ct_bs = _g1h->g1_barrier_set();
66 _ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());
67
68 _card_counts = (jubyte*) mapper->reserved().start();
69 _reserved_max_card_num = mapper->reserved().byte_size();
70 mapper->set_mapping_changed_listener(&_listener);
71 }
72 }
73
74 uint G1CardCounts::add_card_count(jbyte* card_ptr) {
75 // Returns the number of times the card has been refined.
76 // If we failed to reserve/commit the counts table, return 0.
77 // If card_ptr is beyond the committed end of the counts table,
78 // return 0.
79 // Otherwise return the actual count.
80 // Unless G1ConcRSHotCardLimit has been set appropriately,
81 // returning 0 will result in the card being considered
82 // cold and will be refined immediately.
83 uint count = 0;
84 if (has_count_table()) {
85 size_t card_num = ptr_2_card_num(card_ptr);
86 assert(card_num < _reserved_max_card_num,
87 err_msg("Card "SIZE_FORMAT" outside of card counts table (max size "SIZE_FORMAT")",
88 card_num, _reserved_max_card_num));
89 count = (uint) _card_counts[card_num];
90 if (count < G1ConcRSHotCardLimit) {
91 _card_counts[card_num] =
92 (jubyte)(MIN2((uintx)(_card_counts[card_num] + 1), G1ConcRSHotCardLimit));
93 }
94 }
95 return count;
96 }
97
98 bool G1CardCounts::is_hot(uint count) {
99 return (count >= G1ConcRSHotCardLimit);
100 }
101
102 void G1CardCounts::clear_region(HeapRegion* hr) {
103 MemRegion mr(hr->bottom(), hr->end());
104 clear_range(mr);
105 }
106
107 void G1CardCounts::clear_range(MemRegion mr) {
108 if (has_count_table()) {
109 const jbyte* from_card_ptr = _ct_bs->byte_for_const(mr.start());
110 // We use the last address in the range as the range could represent the
111 // last region in the heap. In which case trying to find the card will be an
112 // OOB access to the card table.
113 const jbyte* last_card_ptr = _ct_bs->byte_for_const(mr.last());
114
115 #ifdef ASSERT
116 HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);
117 assert(start_addr == mr.start(), "MemRegion start must be aligned to a card.");
118 HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);
119 assert((last_addr + CardTableModRefBS::card_size_in_words) == mr.end(), "MemRegion end must be aligned to a card.");
120 #endif // ASSERT
121
122 // Clear the counts for the (exclusive) card range.
123 size_t from_card_num = ptr_2_card_num(from_card_ptr);
124 size_t to_card_num = ptr_2_card_num(last_card_ptr) + 1;
125 clear_range(from_card_num, to_card_num);
126 }
127 }
128
129 class G1CardCountsClearClosure : public HeapRegionClosure {
130 private:
131 G1CardCounts* _card_counts;
132 public:
133 G1CardCountsClearClosure(G1CardCounts* card_counts) :
134 HeapRegionClosure(), _card_counts(card_counts) { }
135
136
137 virtual bool doHeapRegion(HeapRegion* r) {
138 _card_counts->clear_region(r);
139 return false;
140 }
141 };
142
143 void G1CardCounts::clear_all() {
144 assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");
145 G1CardCountsClearClosure cl(this);
146 _g1h->heap_region_iterate(&cl);
147 }