1/*
2 * Copyright (c) 2015, 2019, 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/z/zForwarding.inline.hpp"
26#include "gc/z/zPage.inline.hpp"
27#include "gc/z/zUtils.inline.hpp"
28#include "memory/allocation.hpp"
29#include "utilities/debug.hpp"
30
31ZForwarding* ZForwarding::create(ZPage* page) {
32 // Allocate table for linear probing. The size of the table must be
33 // a power of two to allow for quick and inexpensive indexing/masking.
34 // The table is sized to have a load factor of 50%, i.e. sized to have
35 // double the number of entries actually inserted.
36 assert(page->live_objects() > 0, "Invalid value");
37 const uint32_t nentries = ZUtils::round_up_power_of_2(page->live_objects() * 2);
38 return ::new (AttachedArray::alloc(nentries)) ZForwarding(page, nentries);
39}
40
41void ZForwarding::destroy(ZForwarding* forwarding) {
42 AttachedArray::free(forwarding);
43}
44
45ZForwarding::ZForwarding(ZPage* page, uint32_t nentries) :
46 _virtual(page->virtual_memory()),
47 _object_alignment_shift(page->object_alignment_shift()),
48 _entries(nentries),
49 _page(page),
50 _refcount(1),
51 _pinned(false) {}
52
53void ZForwarding::verify() const {
54 guarantee(_refcount > 0, "Invalid refcount");
55 guarantee(_page != NULL, "Invalid page");
56
57 uint32_t live_objects = 0;
58
59 for (ZForwardingCursor i = 0; i < _entries.length(); i++) {
60 const ZForwardingEntry entry = at(&i);
61 if (!entry.populated()) {
62 // Skip empty entries
63 continue;
64 }
65
66 // Check from index
67 guarantee(entry.from_index() < _page->object_max_count(), "Invalid from index");
68
69 // Check for duplicates
70 for (ZForwardingCursor j = i + 1; j < _entries.length(); j++) {
71 const ZForwardingEntry other = at(&j);
72 if (!other.populated()) {
73 // Skip empty entries
74 continue;
75 }
76
77 guarantee(entry.from_index() != other.from_index(), "Duplicate from");
78 guarantee(entry.to_offset() != other.to_offset(), "Duplicate to");
79 }
80
81 live_objects++;
82 }
83
84 // Check number of non-empty entries
85 guarantee(live_objects == _page->live_objects(), "Invalid number of entries");
86}
87