1/*
2 * Copyright 2012-present Facebook, Inc.
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#pragma once
18
19#include <sys/stat.h>
20#include <sys/types.h>
21#include <cstddef>
22#include <string>
23#include <utility>
24#include <vector>
25
26#include <boost/operators.hpp>
27
28#include <folly/Range.h>
29#include <folly/experimental/io/FsUtil.h>
30#include <folly/portability/Unistd.h>
31
32namespace folly {
33
34struct HugePageSize : private boost::totally_ordered<HugePageSize> {
35 explicit HugePageSize(size_t s) : size(s) {}
36
37 fs::path filePath(const fs::path& relpath) const {
38 return mountPoint / relpath;
39 }
40
41 size_t size = 0;
42 fs::path mountPoint;
43 dev_t device = 0;
44};
45
46inline bool operator<(const HugePageSize& a, const HugePageSize& b) {
47 return a.size < b.size;
48}
49
50inline bool operator==(const HugePageSize& a, const HugePageSize& b) {
51 return a.size == b.size;
52}
53
54/**
55 * Vector of (huge_page_size, mount_point), sorted by huge_page_size.
56 * mount_point might be empty if no hugetlbfs file system is mounted for
57 * that size.
58 */
59typedef std::vector<HugePageSize> HugePageSizeVec;
60
61/**
62 * Get list of supported huge page sizes and their mount points, if
63 * hugetlbfs file systems are mounted for those sizes.
64 */
65const HugePageSizeVec& getHugePageSizes();
66
67/**
68 * Return the mount point for the requested huge page size.
69 * 0 = use smallest available.
70 * Returns nullptr if the requested huge page size is not available.
71 */
72const HugePageSize* getHugePageSize(size_t size = 0);
73
74/**
75 * Return the huge page size for a device.
76 * returns nullptr if device does not refer to a huge page filesystem.
77 */
78const HugePageSize* getHugePageSizeForDevice(dev_t device);
79
80} // namespace folly
81