1 /*
 2  * Copyright (c) 2018, 2021, Red Hat, Inc. 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/shared/markBitMap.inline.hpp"
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
29 #include "gc/shenandoah/shenandoahMarkingContext.hpp"
30 #include "gc/shenandoah/shenandoahTaskqueue.inline.hpp"
31 #include "utilities/stack.inline.hpp"
32 
33 ShenandoahMarkingContext::ShenandoahMarkingContext(MemRegion heap_region, MemRegion bitmap_region, size_t num_regions, uint max_queues) :
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   _task_queues(new ShenandoahObjToScanQueueSet(max_queues)) {
40   assert(max_queues > 0, "At least one queue");
41   for (uint i = 0; i < max_queues; ++i) {
42     ShenandoahObjToScanQueue* task_queue = new ShenandoahObjToScanQueue();
43     _task_queues->register_queue(i, task_queue);
44   }
45 }
46 
47 ShenandoahMarkingContext::~ShenandoahMarkingContext() {
48   for (uint i = 0; i < _task_queues->size(); ++i) {
49     ShenandoahObjToScanQueue* q = _task_queues->queue(i);
50     delete q;
51   }
52   delete _task_queues;
53 }
54 
55 bool ShenandoahMarkingContext::is_bitmap_clear() const {
56   ShenandoahHeap* heap = ShenandoahHeap::heap();
57   size_t num_regions = heap->num_regions();
58   for (size_t idx = 0; idx < num_regions; idx++) {
59     ShenandoahHeapRegion* r = heap->get_region(idx);
60     if (heap->is_bitmap_slice_committed(r) && !is_bitmap_clear_range(r->bottom(), r->end())) {
61       return false;
62     }
63   }
64   return true;
65 }
66 
67 bool ShenandoahMarkingContext::is_bitmap_clear_range(HeapWord* start, HeapWord* end) const {
68   return _mark_bit_map.get_next_marked_addr(start, end) == 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   _top_at_mark_starts_base[idx] = bottom;
75   _top_bitmaps[idx] = bottom;
76 }
77 
78 void ShenandoahMarkingContext::clear_bitmap(ShenandoahHeapRegion* r) {
79   HeapWord* bottom = r->bottom();
80   HeapWord* top_bitmap = _top_bitmaps[r->index()];
81   if (top_bitmap > bottom) {
82     _mark_bit_map.clear_range_large(MemRegion(bottom, top_bitmap));
83     _top_bitmaps[r->index()] = bottom;
84   }
85   assert(is_bitmap_clear_range(bottom, r->end()),
86          "Region " SIZE_FORMAT " should have no marks in bitmap", r->index());
87 }
88 
89 bool ShenandoahMarkingContext::is_complete() {
90   return _is_complete.is_set();
91 }
92 
93 void ShenandoahMarkingContext::mark_complete() {
94   _is_complete.set();
95 }
96 
97 void ShenandoahMarkingContext::mark_incomplete() {
98   _is_complete.unset();
99 }