1/*
2 * Copyright (c) 2017, 2018, Oracle and/or its affiliates. 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#include "precompiled.hpp"
25#include "gc/g1/g1BlockOffsetTable.hpp"
26#include "gc/g1/g1CollectedHeap.hpp"
27#include "gc/g1/g1ConcurrentMarkBitMap.inline.hpp"
28#include "gc/g1/heapRegion.inline.hpp"
29#include "gc/shared/referenceProcessor.hpp"
30#include "runtime/interfaceSupport.inline.hpp"
31#include "runtime/vmOperations.hpp"
32#include "runtime/vmThread.hpp"
33#include "unittest.hpp"
34
35class VerifyAndCountMarkClosure : public StackObj {
36 int _count;
37 G1CMBitMap* _bm;
38
39 void ensure_marked(HeapWord* addr) {
40 ASSERT_TRUE(_bm->is_marked(addr));
41 }
42
43public:
44 VerifyAndCountMarkClosure(G1CMBitMap* bm) : _count(0), _bm(bm) { }
45
46 virtual size_t apply(oop object) {
47 _count++;
48 ensure_marked((HeapWord*) object);
49 // Must return positive size to advance the iteration.
50 return MinObjAlignment;
51 }
52
53 void reset() {
54 _count = 0;
55 }
56
57 int count() {
58 return _count;
59 }
60};
61
62#define MARK_OFFSET_1 ( 17 * MinObjAlignment)
63#define MARK_OFFSET_2 ( 99 * MinObjAlignment)
64#define MARK_OFFSET_3 (337 * MinObjAlignment)
65
66class VM_HeapRegionApplyToMarkedObjectsTest : public VM_GTestExecuteAtSafepoint {
67public:
68 void doit();
69};
70
71void VM_HeapRegionApplyToMarkedObjectsTest::doit() {
72 G1CollectedHeap* heap = G1CollectedHeap::heap();
73
74 // Using region 0 for testing.
75 HeapRegion* region = heap->heap_region_containing(heap->bottom_addr_for_region(0));
76
77 // Mark some "oops" in the bitmap.
78 G1CMBitMap* bitmap = heap->concurrent_mark()->next_mark_bitmap();
79 bitmap->mark(region->bottom());
80 bitmap->mark(region->bottom() + MARK_OFFSET_1);
81 bitmap->mark(region->bottom() + MARK_OFFSET_2);
82 bitmap->mark(region->bottom() + MARK_OFFSET_3);
83 bitmap->mark(region->end());
84
85 VerifyAndCountMarkClosure cl(bitmap);
86
87 HeapWord* old_top = region->top();
88
89 // When top is equal to bottom the closure should not be
90 // applied to any object because apply_to_marked_objects
91 // will stop at HeapRegion::scan_limit which is equal to top.
92 region->set_top(region->bottom());
93 region->apply_to_marked_objects(bitmap, &cl);
94 EXPECT_EQ(0, cl.count());
95 cl.reset();
96
97 // Set top to offset_1 and expect only to find 1 entry (bottom)
98 region->set_top(region->bottom() + MARK_OFFSET_1);
99 region->apply_to_marked_objects(bitmap, &cl);
100 EXPECT_EQ(1, cl.count());
101 cl.reset();
102
103 // Set top to (offset_2 + 1) and expect only to find 3
104 // entries (bottom, offset_1 and offset_2)
105 region->set_top(region->bottom() + MARK_OFFSET_2 + MinObjAlignment);
106 region->apply_to_marked_objects(bitmap, &cl);
107 EXPECT_EQ(3, cl.count());
108 cl.reset();
109
110 // Still expect same 3 entries when top is (offset_3 - 1)
111 region->set_top(region->bottom() + MARK_OFFSET_3 - MinObjAlignment);
112 region->apply_to_marked_objects(bitmap, &cl);
113 EXPECT_EQ(3, cl.count());
114 cl.reset();
115
116 // Setting top to end should render 4 entries.
117 region->set_top(region->end());
118 region->apply_to_marked_objects(bitmap, &cl);
119 EXPECT_EQ(4, cl.count());
120 cl.reset();
121
122 region->set_top(old_top);
123}
124
125TEST_VM(HeapRegion, apply_to_marked_object) {
126 if (!UseG1GC) {
127 return;
128 }
129
130 // Run the test in our very own safepoint, because otherwise it
131 // modifies a region behind the back of a possibly using allocation
132 // or running GC.
133 VM_HeapRegionApplyToMarkedObjectsTest op;
134 ThreadInVMfromNative invm(JavaThread::current());
135 VMThread::execute(&op);
136}
137