1/*
2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved.
3 *
4 * This code is free software; you can redistribute it and/or modify it
5 * under the terms of the GNU General Public License version 2 only, as
6 * published by the Free Software Foundation.
7 *
8 * This code is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
11 * version 2 for more details (a copy is included in the LICENSE file that
12 * accompanied this code).
13 *
14 * You should have received a copy of the GNU General Public License version
15 * 2 along with this work; if not, write to the Free Software Foundation,
16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17 *
18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19 * or visit www.oracle.com if you need additional information or have any
20 * questions.
21 *
22 */
23
24#include "precompiled.hpp"
25#include "gc/shared/markBitMap.inline.hpp"
26#include "gc/shenandoah/shenandoahHeap.hpp"
27#include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
28#include "gc/shenandoah/shenandoahMarkingContext.hpp"
29
30ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions) :
31 _top_bitmaps(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),
32 _top_at_mark_starts_base(NEW_C_HEAP_ARRAY(HeapWord*, num_regions, mtGC)),
33 _top_at_mark_starts(_top_at_mark_starts_base -
34 ((uintx) heap_region.start() >> ShenandoahHeapRegion::region_size_bytes_shift())) {
35 _mark_bit_map.initialize(heap_region, bitmap_region);
36}
37
38bool ShenandoahMarkingContext::is_bitmap_clear() const {
39 ShenandoahHeap* heap = ShenandoahHeap::heap();
40 size_t num_regions = heap->num_regions();
41 for (size_t idx = 0; idx < num_regions; idx++) {
42 ShenandoahHeapRegion* r = heap->get_region(idx);
43 if (heap->is_bitmap_slice_committed(r) && !is_bitmap_clear_range(r->bottom(), r->end())) {
44 return false;
45 }
46 }
47 return true;
48}
49
50bool ShenandoahMarkingContext::is_bitmap_clear_range(HeapWord* start, HeapWord* end) const {
51 return _mark_bit_map.get_next_marked_addr(start, end) == end;
52}
53
54void ShenandoahMarkingContext::initialize_top_at_mark_start(ShenandoahHeapRegion* r) {
55 size_t idx = r->region_number();
56 HeapWord *bottom = r->bottom();
57 _top_at_mark_starts_base[idx] = bottom;
58 _top_bitmaps[idx] = bottom;
59}
60
61void ShenandoahMarkingContext::capture_top_at_mark_start(ShenandoahHeapRegion *r) {
62 size_t region_number = r->region_number();
63 HeapWord* old_tams = _top_at_mark_starts_base[region_number];
64 HeapWord* new_tams = r->top();
65
66 assert(new_tams >= old_tams,
67 "Region " SIZE_FORMAT", TAMS updates should be monotonic: " PTR_FORMAT " -> " PTR_FORMAT,
68 region_number, p2i(old_tams), p2i(new_tams));
69 assert(is_bitmap_clear_range(old_tams, new_tams),
70 "Region " SIZE_FORMAT ", bitmap should be clear while adjusting TAMS: " PTR_FORMAT " -> " PTR_FORMAT,
71 region_number, p2i(old_tams), p2i(new_tams));
72
73 _top_at_mark_starts_base[region_number] = new_tams;
74 _top_bitmaps[region_number] = new_tams;
75}
76
77void ShenandoahMarkingContext::reset_top_at_mark_start(ShenandoahHeapRegion* r) {
78 _top_at_mark_starts_base[r->region_number()] = r->bottom();
79}
80
81HeapWord* ShenandoahMarkingContext::top_at_mark_start(ShenandoahHeapRegion* r) const {
82 return _top_at_mark_starts_base[r->region_number()];
83}
84
85void ShenandoahMarkingContext::reset_top_bitmap(ShenandoahHeapRegion* r) {
86 assert(is_bitmap_clear_range(r->bottom(), r->end()),
87 "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number());
88 _top_bitmaps[r->region_number()] = r->bottom();
89}
90
91void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) {
92 HeapWord* bottom = r->bottom();
93 HeapWord* top_bitmap = _top_bitmaps[r->region_number()];
94 if (top_bitmap > bottom) {
95 _mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap));
96 _top_bitmaps[r->region_number()] = bottom;
97 }
98 assert(is_bitmap_clear_range(bottom, r->end()),
99 "Region " SIZE_FORMAT " should have no marks in bitmap", r->region_number());
100}
101
102bool ShenandoahMarkingContext::is_complete() {
103 return _is_complete.is_set();
104}
105
106void ShenandoahMarkingContext::mark_complete() {
107 _is_complete.set();
108}
109
110void ShenandoahMarkingContext::mark_incomplete() {
111 _is_complete.unset();
112}
113