1 /*
2 * Copyright (c) 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
27 #include "gc/shenandoah/shenandoahHeap.inline.hpp"
28 #include "gc/shenandoah/shenandoahHeapRegion.hpp"
29 #include "gc/shenandoah/shenandoahMarkClosures.hpp"
30 #include "gc/shenandoah/shenandoahMarkingContext.hpp"
31 #include "gc/shenandoah/shenandoahSharedVariables.hpp"
32
33
34 ShenandoahFinalMarkUpdateRegionStateClosure::ShenandoahFinalMarkUpdateRegionStateClosure(
35 ShenandoahMarkingContext *ctx) :
36 _ctx(ctx), _lock(ShenandoahHeap::heap()->lock()) {}
37
38 void ShenandoahFinalMarkUpdateRegionStateClosure::heap_region_do(ShenandoahHeapRegion* r) {
39 if (r->is_active()) {
40 // All allocations past TAMS are implicitly live, adjust the region data.
41 // Bitmaps/TAMS are swapped at this point, so we need to poll complete bitmap.
42 HeapWord *tams = _ctx->top_at_mark_start(r);
43 HeapWord *top = r->top();
44 if (top > tams) {
45 r->increase_live_data_alloc_words(pointer_delta(top, tams));
46 }
47
48 // We are about to select the collection set, make sure it knows about
49 // current pinning status. Also, this allows trashing more regions that
50 // now have their pinning status dropped.
51 if (r->is_pinned()) {
52 if (r->pin_count() == 0) {
53 ShenandoahHeapLocker locker(_lock);
54 r->make_unpinned();
55 }
56 } else {
57 if (r->pin_count() > 0) {
58 ShenandoahHeapLocker locker(_lock);
59 r->make_pinned();
60 }
61 }
62
63 if (ShenandoahHeap::heap()->mode()->is_generational()) {
64 // Allocations move the watermark when top moves, however compacting
65 // objects will sometimes lower top beneath the watermark, after which,
66 // attempts to read the watermark will assert out (watermark should not be
67 // higher than top). The right way™ to check for new allocations is to compare
68 // top with the TAMS as is done earlier in this function.
69 if (top > tams) {
70 // There have been allocations in this region since the start of the cycle.
71 // Any objects new to this region must not assimilate elevated age.
72 r->reset_age();
73 } else if (ShenandoahHeap::heap()->is_aging_cycle()) {
74 r->increment_age();
75 }
76 }
77
78 // Remember limit for updating refs. It's guaranteed that we get no
79 // from-space-refs written from here on.
80 r->set_update_watermark_at_safepoint(r->top());
81 } else {
82 assert(!r->has_live(), "Region " SIZE_FORMAT " should have no live data", r->index());
83 assert(_ctx->top_at_mark_start(r) == r->top(),
84 "Region " SIZE_FORMAT " should have correct TAMS", r->index());
85 }
86 }
87
88 ShenandoahCaptureUpdateWaterMarkForOld::ShenandoahCaptureUpdateWaterMarkForOld(ShenandoahMarkingContext* ctx) :
89 _ctx(ctx), _lock(ShenandoahHeap::heap()->lock()) {}
90
91 void ShenandoahCaptureUpdateWaterMarkForOld::heap_region_do(ShenandoahHeapRegion* r) {
92 // Remember limit for updating refs. It's guaranteed that we get no from-space-refs written from here on.
93 r->set_update_watermark_at_safepoint(r->top());
94 }