1 /*
2 * Copyright (c) 2019, 2021, 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/g1/g1CollectionSetCandidates.hpp"
27 #include "gc/g1/g1CollectionSetChooser.hpp"
28 #include "gc/g1/heapRegion.inline.hpp"
29
remove(uint num_regions)30 void G1CollectionSetCandidates::remove(uint num_regions) {
31 assert(num_regions <= num_remaining(), "Trying to remove more regions (%u) than available (%u)", num_regions, num_remaining());
32 for (uint i = 0; i < num_regions; i++) {
33 _remaining_reclaimable_bytes -= at(_front_idx)->reclaimable_bytes();
34 _front_idx++;
35 }
36 }
37
remove_from_end(uint num_remove,size_t wasted)38 void G1CollectionSetCandidates::remove_from_end(uint num_remove, size_t wasted) {
39 assert(num_remove <= num_remaining(), "trying to remove more regions than remaining");
40
41 #ifdef ASSERT
42 size_t reclaimable = 0;
43
44 for (uint i = 0; i < num_remove; i++) {
45 uint cur_idx = _num_regions - i - 1;
46 reclaimable += at(cur_idx)->reclaimable_bytes();
47 // Make sure we crash if we access it.
48 _regions[cur_idx] = NULL;
49 }
50
51 assert(reclaimable == wasted, "Recalculated reclaimable inconsistent");
52 #endif
53 _num_regions -= num_remove;
54 _remaining_reclaimable_bytes -= wasted;
55 }
56
iterate(HeapRegionClosure * cl)57 void G1CollectionSetCandidates::iterate(HeapRegionClosure* cl) {
58 for (uint i = _front_idx; i < _num_regions; i++) {
59 HeapRegion* r = _regions[i];
60 if (cl->do_heap_region(r)) {
61 cl->set_incomplete();
62 break;
63 }
64 }
65 }
66
iterate_backwards(HeapRegionClosure * cl)67 void G1CollectionSetCandidates::iterate_backwards(HeapRegionClosure* cl) {
68 for (uint i = _num_regions; i > _front_idx; i--) {
69 HeapRegion* r = _regions[i - 1];
70 if (cl->do_heap_region(r)) {
71 cl->set_incomplete();
72 break;
73 }
74 }
75 }
76
77 #ifndef PRODUCT
verify() const78 void G1CollectionSetCandidates::verify() const {
79 guarantee(_front_idx <= _num_regions, "Index: %u Num_regions: %u", _front_idx, _num_regions);
80 uint idx = _front_idx;
81 size_t sum_of_reclaimable_bytes = 0;
82 HeapRegion *prev = NULL;
83 for (; idx < _num_regions; idx++) {
84 HeapRegion *cur = _regions[idx];
85 guarantee(cur != NULL, "Regions after _front_idx %u cannot be NULL but %u is", _front_idx, idx);
86 // The first disjunction filters out regions with objects that were explicitly
87 // pinned after being added to the collection set candidates. Archive regions
88 // should never have been added to the collection set though.
89 guarantee((cur->is_pinned() && !cur->is_archive()) ||
90 G1CollectionSetChooser::should_add(cur),
91 "Region %u should be eligible for addition.", cur->hrm_index());
92 if (prev != NULL) {
93 guarantee(prev->gc_efficiency() >= cur->gc_efficiency(),
94 "GC efficiency for region %u: %1.4f smaller than for region %u: %1.4f",
95 prev->hrm_index(), prev->gc_efficiency(), cur->hrm_index(), cur->gc_efficiency());
96 }
97 sum_of_reclaimable_bytes += cur->reclaimable_bytes();
98 prev = cur;
99 }
100 guarantee(sum_of_reclaimable_bytes == _remaining_reclaimable_bytes,
101 "Inconsistent remaining_reclaimable bytes, remaining " SIZE_FORMAT " calculated " SIZE_FORMAT,
102 _remaining_reclaimable_bytes, sum_of_reclaimable_bytes);
103 }
104 #endif // !PRODUCT
105