1 /*
2 * Copyright (c) 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
28 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
29 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
30 #include "gc/shenandoah/shenandoahMarkClosures.hpp"
31 #include "gc/shenandoah/shenandoahMarkingContext.hpp"
32 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
33
34
35 ShenandoahFinalMarkUpdateRegionStateClosure::ShenandoahFinalMarkUpdateRegionStateClosure(
36 ShenandoahMarkingContext *ctx) :
37 _ctx(ctx), _lock(ShenandoahHeap::heap()->lock()) {}
38
39 void ShenandoahFinalMarkUpdateRegionStateClosure::heap_region_do(ShenandoahHeapRegion* r) {
40 if (r->is_active()) {
41 if (_ctx != nullptr) {
42 // _ctx may be null when this closure is used to sync only the pin status
43 // update the watermark of old regions. For old regions we cannot reset
44 // the TAMS because we rely on that to keep promoted objects alive after
45 // old marking is complete.
46
47 // All allocations past TAMS are implicitly live, adjust the region data.
48 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
49 HeapWord *tams = _ctx->top_at_mark_start(r);
50 HeapWord *top = r->top();
51 if (top > tams) {
52 r->increase_live_data_alloc_words(pointer_delta(top, tams));
53 }
54 }
55
56 // We are about to select the collection set, make sure it knows about
57 // current pinning status. Also, this allows trashing more regions that
58 // now have their pinning status dropped.
59 if (r->is_pinned()) {
60 if (r->pin_count() == 0) {
61 ShenandoahHeapLocker locker(_lock);
62 r->make_unpinned();
63 }
64 } else {
65 if (r->pin_count() > 0) {
66 ShenandoahHeapLocker locker(_lock);
67 r->make_pinned();
68 }
69 }
70
71 // Remember limit for updating refs. It's guaranteed that we get no
72 // from-space-refs written from here on.
73 r->set_update_watermark_at_safepoint(r->top());
74 } else {
75 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
76 assert(_ctx == nullptr || _ctx->top_at_mark_start(r) == r->top(),
77 "Region " SIZE_FORMAT " should have correct TAMS", r->index());
78 }
79 }
80
81
82 ShenandoahUpdateCensusZeroCohortClosure::ShenandoahUpdateCensusZeroCohortClosure(
83 ShenandoahMarkingContext *ctx) :
84 _ctx(ctx), _age0_pop(0), _total_pop(0) {}
85
86 void ShenandoahUpdateCensusZeroCohortClosure::heap_region_do(ShenandoahHeapRegion* r) {
87 if (_ctx != nullptr && r->is_active()) {
88 assert(r->is_young(), "Young regions only");
89 HeapWord* tams = _ctx->top_at_mark_start(r);
90 HeapWord* top = r->top();
91 if (top > tams) {
92 _age0_pop += pointer_delta(top, tams);
93 }
94 // TODO: check significance of _ctx != nullptr above, can that
95 // spoof _total_pop in some corner cases?
96 NOT_PRODUCT(_total_pop += r->get_live_data_words();)
97 }
98 }