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comparison src/share/vm/gc_implementation/g1/g1CardCounts.cpp @ 10246:194f52aa2f23

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7176479: G1: JVM crashes on T5-8 system with 1.5 TB heap Summary: Refactor G1's hot card cache and card counts table into their own files. Simplify the card counts table, including removing the encoding of the card index in each entry. The card counts table now has a 1:1 correspondence with the cards spanned by heap. Space for the card counts table is reserved from virtual memory (rather than C heap) during JVM startup and is committed/expanded when the heap is expanded. Changes were also reviewed-by Vitaly Davidovich. Reviewed-by: tschatzl, jmasa
author johnc
date Thu, 09 May 2013 11:16:39 -0700
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10245:923ac8d1df95 10246:194f52aa2f23
1 /*
2 * Copyright (c) 2013, 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 void G1CardCounts::clear_range(size_t from_card_num, size_t to_card_num) {
35 if (has_count_table()) {
36 check_card_num(from_card_num,
37 err_msg("from card num out of range: "SIZE_FORMAT, from_card_num));
38 assert(from_card_num < to_card_num,
39 err_msg("Wrong order? from: " SIZE_FORMAT ", to: "SIZE_FORMAT,
40 from_card_num, to_card_num));
41 assert(to_card_num <= _committed_max_card_num,
42 err_msg("to card num out of range: "
43 "to: "SIZE_FORMAT ", "
44 "max: "SIZE_FORMAT,
45 to_card_num, _committed_max_card_num));
46
47 to_card_num = MIN2(_committed_max_card_num, to_card_num);
48
49 Copy::fill_to_bytes(&_card_counts[from_card_num], (to_card_num - from_card_num));
50 }
51 }
52
53 G1CardCounts::G1CardCounts(G1CollectedHeap *g1h):
54 _g1h(g1h), _card_counts(NULL),
55 _reserved_max_card_num(0), _committed_max_card_num(0),
56 _committed_size(0) {}
57
58 void G1CardCounts::initialize() {
59 assert(_g1h->max_capacity() > 0, "initialization order");
60 assert(_g1h->capacity() == 0, "initialization order");
61
62 if (G1ConcRSHotCardLimit > 0) {
63 // The max value we can store in the counts table is
64 // max_jubyte. Guarantee the value of the hot
65 // threshold limit is no more than this.
66 guarantee(G1ConcRSHotCardLimit <= max_jubyte, "sanity");
67
68 ModRefBarrierSet* bs = _g1h->mr_bs();
69 guarantee(bs->is_a(BarrierSet::CardTableModRef), "Precondition");
70 _ct_bs = (CardTableModRefBS*)bs;
71 _ct_bot = _ct_bs->byte_for_const(_g1h->reserved_region().start());
72
73 // Allocate/Reserve the counts table
74 size_t reserved_bytes = _g1h->max_capacity();
75 _reserved_max_card_num = reserved_bytes >> CardTableModRefBS::card_shift;
76
77 size_t reserved_size = _reserved_max_card_num * sizeof(jbyte);
78 ReservedSpace rs(ReservedSpace::allocation_align_size_up(reserved_size));
79 if (!rs.is_reserved()) {
80 warning("Could not reserve enough space for the card counts table");
81 guarantee(!has_reserved_count_table(), "should be NULL");
82 return;
83 }
84
85 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
86
87 _card_counts_storage.initialize(rs, 0);
88 _card_counts = (jubyte*) _card_counts_storage.low();
89 }
90 }
91
92 void G1CardCounts::resize(size_t heap_capacity) {
93 // Expand the card counts table to handle a heap with the given capacity.
94
95 if (!has_reserved_count_table()) {
96 // Don't expand if we failed to reserve the card counts table.
97 return;
98 }
99
100 assert(_committed_size ==
101 ReservedSpace::allocation_align_size_up(_committed_size),
102 err_msg("Unaligned? committed_size: " SIZE_FORMAT, _committed_size));
103
104 // Verify that the committed space for the card counts
105 // matches our committed max card num.
106 size_t prev_committed_size = _committed_size;
107 size_t prev_committed_card_num = prev_committed_size / sizeof(jbyte);
108 assert(prev_committed_card_num == _committed_max_card_num,
109 err_msg("Card mismatch: "
110 "prev: " SIZE_FORMAT ", "
111 "committed: "SIZE_FORMAT,
112 prev_committed_card_num, _committed_max_card_num));
113
114 size_t new_size = (heap_capacity >> CardTableModRefBS::card_shift) * sizeof(jbyte);
115 size_t new_committed_size = ReservedSpace::allocation_align_size_up(new_size);
116 size_t new_committed_card_num =
117 MIN2(_reserved_max_card_num, new_committed_size / sizeof(jbyte));
118
119 if (_committed_max_card_num < new_committed_card_num) {
120 // we need to expand the backing store for the card counts
121 size_t expand_size = new_committed_size - prev_committed_size;
122
123 if (!_card_counts_storage.expand_by(expand_size)) {
124 warning("Card counts table backing store commit failure");
125 return;
126 }
127 assert(_card_counts_storage.committed_size() == new_committed_size,
128 "expansion commit failure");
129
130 _committed_size = new_committed_size;
131 _committed_max_card_num = new_committed_card_num;
132
133 clear_range(prev_committed_card_num, _committed_max_card_num);
134 }
135 }
136
137 uint G1CardCounts::add_card_count(jbyte* card_ptr) {
138 // Returns the number of times the card has been refined.
139 // If we failed to reserve/commit the counts table, return 0.
140 // If card_ptr is beyond the committed end of the counts table,
141 // return 0.
142 // Otherwise return the actual count.
143 // Unless G1ConcRSHotCardLimit has been set appropriately,
144 // returning 0 will result in the card being considered
145 // cold and will be refined immediately.
146 uint count = 0;
147 if (has_count_table()) {
148 size_t card_num = ptr_2_card_num(card_ptr);
149 if (card_num < _committed_max_card_num) {
150 count = (uint) _card_counts[card_num];
151 if (count < G1ConcRSHotCardLimit) {
152 _card_counts[card_num] += 1;
153 }
154 assert(_card_counts[card_num] <= G1ConcRSHotCardLimit,
155 err_msg("Refinement count overflow? "
156 "new count: "UINT32_FORMAT,
157 (uint) _card_counts[card_num]));
158 }
159 }
160 return count;
161 }
162
163 bool G1CardCounts::is_hot(uint count) {
164 return (count >= G1ConcRSHotCardLimit);
165 }
166
167 void G1CardCounts::clear_region(HeapRegion* hr) {
168 assert(!hr->isHumongous(), "Should have been cleared");
169 if (has_count_table()) {
170 HeapWord* bottom = hr->bottom();
171
172 // We use the last address in hr as hr could be the
173 // last region in the heap. In which case trying to find
174 // the card for hr->end() will be an OOB accesss to the
175 // card table.
176 HeapWord* last = hr->end() - 1;
177 assert(_g1h->g1_committed().contains(last),
178 err_msg("last not in committed: "
179 "last: " PTR_FORMAT ", "
180 "committed: [" PTR_FORMAT ", " PTR_FORMAT ")",
181 last,
182 _g1h->g1_committed().start(),
183 _g1h->g1_committed().end()));
184
185 const jbyte* from_card_ptr = _ct_bs->byte_for_const(bottom);
186 const jbyte* last_card_ptr = _ct_bs->byte_for_const(last);
187
188 #ifdef ASSERT
189 HeapWord* start_addr = _ct_bs->addr_for(from_card_ptr);
190 assert(start_addr == hr->bottom(), "alignment");
191 HeapWord* last_addr = _ct_bs->addr_for(last_card_ptr);
192 assert((last_addr + CardTableModRefBS::card_size_in_words) == hr->end(), "alignment");
193 #endif // ASSERT
194
195 // Clear the counts for the (exclusive) card range.
196 size_t from_card_num = ptr_2_card_num(from_card_ptr);
197 size_t to_card_num = ptr_2_card_num(last_card_ptr) + 1;
198 clear_range(from_card_num, to_card_num);
199 }
200 }
201
202 void G1CardCounts::clear_all() {
203 assert(SafepointSynchronize::is_at_safepoint(), "don't call this otherwise");
204 clear_range((size_t)0, _committed_max_card_num);
205 }
206
207 G1CardCounts::~G1CardCounts() {
208 if (has_reserved_count_table()) {
209 _card_counts_storage.release();
210 }
211 }
212