1/*
2 * Copyright (c) 2018, 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
25#include "precompiled.hpp"
26#include "gc/parallel/psFileBackedVirtualspace.hpp"
27#include "memory/virtualspace.hpp"
28#include "runtime/os.inline.hpp"
29
30PSFileBackedVirtualSpace::PSFileBackedVirtualSpace(ReservedSpace rs, size_t alignment, const char* path) : PSVirtualSpace(rs, alignment),
31 _file_path(path), _fd(-1), _mapping_succeeded(false) {
32 assert(!rs.special(), "ReservedSpace passed to PSFileBackedVirtualSpace cannot be special");
33}
34
35bool PSFileBackedVirtualSpace::initialize() {
36 _fd = os::create_file_for_heap(_file_path);
37 if (_fd == -1) {
38 return false;
39 }
40 // We map the reserved space to a file at initialization.
41 char* ret = os::replace_existing_mapping_with_file_mapping(reserved_low_addr(), reserved_size(), _fd);
42 if (ret != reserved_low_addr()) {
43 os::close(_fd);
44 return false;
45 }
46 // _mapping_succeeded is false if we return before this point.
47 // expand calls later check value of this flag and return error if it is false.
48 _mapping_succeeded = true;
49 _special = true;
50 os::close(_fd);
51 return true;
52}
53
54bool PSFileBackedVirtualSpace::expand_by(size_t bytes) {
55 assert(special(), "Since entire space is committed at initialization, _special should always be true for PSFileBackedVirtualSpace");
56
57 // if mapping did not succeed during intialization return false
58 if (!_mapping_succeeded) {
59 return false;
60 }
61 return PSVirtualSpace::expand_by(bytes);
62
63}
64
65bool PSFileBackedVirtualSpace::shrink_by(size_t bytes) {
66 assert(special(), "Since entire space is committed at initialization, _special should always be true for PSFileBackedVirtualSpace");
67 return PSVirtualSpace::shrink_by(bytes);
68}
69
70size_t PSFileBackedVirtualSpace::expand_into(PSVirtualSpace* space, size_t bytes) {
71 // not supported. Since doing this will change page mapping which will lead to large TLB penalties.
72 assert(false, "expand_into() should not be called for PSFileBackedVirtualSpace");
73 return 0;
74}
75
76void PSFileBackedVirtualSpace::release() {
77 os::close(_fd);
78 _fd = -1;
79 _file_path = NULL;
80
81 PSVirtualSpace::release();
82}
83
84