1 /*
2 * Copyright (c) 2018, 2021, Red Hat, Inc. All rights reserved.
3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 *
6 * This code is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation.
9 *
10 * This code is distributed in the hope that it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
13 * version 2 for more details (a copy is included in the LICENSE file that
14 * accompanied this code).
15 *
16 * You should have received a copy of the GNU General Public License version
17 * 2 along with this work; if not, write to the Free Software Foundation,
18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19 *
20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21 * or visit www.oracle.com if you need additional information or have any
22 * questions.
23 *
24 */
25
26 #include "precompiled.hpp"
27 #include "gc/shared/markBitMap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
29 #include "gc/shenandoah/shenandoahMarkingContext.hpp"
30
31 #include "shenandoahGlobalGeneration.hpp"
32
33 ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions) :
34 _mark_bit_map(heap_region, bitmap_region),
35 _top_bitmaps(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),
36 _top_at_mark_starts_base(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),
37 _top_at_mark_starts(_top_at_mark_starts_base -
38 ((uintx) heap_region.start() >> ShenandoahHeapRegion::region_size_bytes_shift())) {
39 }
40
41 bool ShenandoahMarkingContext::is_bitmap_clear() const {
42 ShenandoahHeap* heap = ShenandoahHeap::heap();
43 size_t num_regions = heap->num_regions();
44 for (size_t idx = 0; idx < num_regions; idx++) {
45 ShenandoahHeapRegion* r = heap->get_region(idx);
46 if (r->is_affiliated() && heap->is_bitmap_slice_committed(r)
47 && !is_bitmap_range_within_region_clear(r->bottom(), r->end())) {
48 return false;
49 }
50 }
51 return true;
52 }
53
54 bool ShenandoahMarkingContext::is_bitmap_range_within_region_clear(const HeapWord* start, const HeapWord* end) const {
55 assert(start <= end, "Invalid start " PTR_FORMAT " and end " PTR_FORMAT, p2i(start), p2i(end));
56 if (start < end) {
57 ShenandoahHeap* heap = ShenandoahHeap::heap();
58 size_t start_idx = heap->heap_region_index_containing(start);
59 #ifdef ASSERT
60 size_t end_idx = heap->heap_region_index_containing(end - 1);
61 assert(start_idx == end_idx, "Expected range to be within same region (" SIZE_FORMAT ", " SIZE_FORMAT ")", start_idx, end_idx);
62 #endif
63 ShenandoahHeapRegion* r = heap->get_region(start_idx);
64 if (!heap->is_bitmap_slice_committed(r)) {
65 return true;
66 }
67 }
68 return _mark_bit_map.is_bitmap_clear_range(start, end);
69 }
70
71 void ShenandoahMarkingContext::initialize_top_at_mark_start(ShenandoahHeapRegion* r) {
72 size_t idx = r->index();
73 HeapWord *bottom = r->bottom();
74
75 _top_at_mark_starts_base[idx] = bottom;
76 _top_bitmaps[idx] = bottom;
77
78 log_debug(gc)("SMC:initialize_top_at_mark_start for Region " SIZE_FORMAT ", TAMS: " PTR_FORMAT ", TopOfBitMap: " PTR_FORMAT,
79 r->index(), p2i(bottom), p2i(r->end()));
80 }
81
82 HeapWord* ShenandoahMarkingContext::top_bitmap(ShenandoahHeapRegion* r) {
83 return _top_bitmaps[r->index()];
84 }
85
86 void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) {
87 HeapWord* bottom = r->bottom();
88 HeapWord* top_bitmap = _top_bitmaps[r->index()];
89
90 log_debug(gc)("SMC:clear_bitmap for %s Region " SIZE_FORMAT ", top_bitmap: " PTR_FORMAT,
91 r->affiliation_name(), r->index(), p2i(top_bitmap));
92
93 if (top_bitmap > bottom) {
94 _mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap));
95 _top_bitmaps[r->index()] = bottom;
96 }
97
98 assert(is_bitmap_range_within_region_clear(bottom, r->end()),
99 "Region " SIZE_FORMAT " should have no marks in bitmap", r->index());
100 }