2 * Copyright 2017 Facebook, Inc.
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
8 * http://www.apache.org/licenses/LICENSE-2.0
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.
17 #include <folly/experimental/io/HugePages.h>
21 #include <sys/types.h>
28 #include <system_error>
30 #include <boost/regex.hpp>
32 #include <folly/Conv.h>
33 #include <folly/CppAttributes.h>
34 #include <folly/Format.h>
35 #include <folly/Range.h>
36 #include <folly/String.h>
38 #include <folly/gen/Base.h>
39 #include <folly/gen/File.h>
40 #include <folly/gen/String.h>
46 // Get the default huge page size
47 size_t getDefaultHugePageSize() {
48 // We need to parse /proc/meminfo
49 static const boost::regex regex(R"!(Hugepagesize:\s*(\d+)\s*kB)!");
53 bool error = gen::byLine("/proc/meminfo") | [&](StringPiece line) -> bool {
54 if (boost::regex_match(line.begin(), line.end(), match, regex)) {
56 line.begin() + match.position(1), size_t(match.length(1)));
57 pageSize = to<size_t>(numStr) * 1024; // in KiB
64 throw std::runtime_error("Can't find default huge page size");
69 // Get raw huge page sizes (without mount points, they'll be filled later)
70 HugePageSizeVec readRawHugePageSizes() {
71 // We need to parse file names from /sys/kernel/mm/hugepages
72 static const boost::regex regex(R"!(hugepages-(\d+)kB)!");
75 fs::path path("/sys/kernel/mm/hugepages");
76 for (fs::directory_iterator it(path); it != fs::directory_iterator(); ++it) {
77 std::string filename(it->path().filename().string());
78 if (boost::regex_match(filename, match, regex)) {
80 filename.data() + match.position(1), size_t(match.length(1)));
81 vec.emplace_back(to<size_t>(numStr) * 1024);
87 // Parse the value of a pagesize mount option
88 // Format: number, optional K/M/G/T suffix, trailing junk allowed
89 size_t parsePageSizeValue(StringPiece value) {
90 static const boost::regex regex(R"!((\d+)([kmgt])?.*)!", boost::regex::icase);
92 if (!boost::regex_match(value.begin(), value.end(), match, regex)) {
93 throw std::runtime_error("Invalid pagesize option");
96 if (match.length(2) != 0) {
97 c = char(tolower(value[size_t(match.position(2))]));
99 StringPiece numStr(value.data() + match.position(1), size_t(match.length(1)));
100 auto const size = to<size_t>(numStr);
101 auto const mult = [c] {
119 * Get list of supported huge page sizes and their mount points, if
120 * hugetlbfs file systems are mounted for those sizes.
122 HugePageSizeVec readHugePageSizes() {
123 HugePageSizeVec sizeVec = readRawHugePageSizes();
124 if (sizeVec.empty()) {
125 return sizeVec; // nothing to do
127 std::sort(sizeVec.begin(), sizeVec.end());
129 size_t defaultHugePageSize = getDefaultHugePageSize();
131 struct PageSizeLess {
132 bool operator()(const HugePageSize& a, size_t b) const {
135 bool operator()(size_t a, const HugePageSize& b) const {
140 // Read and parse /proc/mounts
141 std::vector<StringPiece> parts;
142 std::vector<StringPiece> options;
144 gen::byLine("/proc/mounts") | gen::eachAs<StringPiece>() |
145 [&](StringPiece line) {
147 split(" ", line, parts);
148 // device path fstype options uid gid
149 if (parts.size() != 6) {
150 throw std::runtime_error("Invalid /proc/mounts line");
152 if (parts[2] != "hugetlbfs") {
153 return; // we only care about hugetlbfs
157 split(",", parts[3], options);
158 size_t pageSize = defaultHugePageSize;
159 // Search for the "pagesize" option, which must have a value
160 for (auto& option : options) {
162 const char* p = static_cast<const char*>(
163 memchr(option.data(), '=', option.size()));
167 if (StringPiece(option.data(), p) != "pagesize") {
170 pageSize = parsePageSizeValue(StringPiece(p + 1, option.end()));
174 auto pos = std::lower_bound(
175 sizeVec.begin(), sizeVec.end(), pageSize, PageSizeLess());
176 if (pos == sizeVec.end() || pos->size != pageSize) {
177 throw std::runtime_error("Mount page size not found");
179 if (!pos->mountPoint.empty()) {
180 // Only one mount point per page size is allowed
185 fs::path path(parts[1].begin(), parts[1].end());
187 const int ret = stat(path.string().c_str(), &st);
188 if (ret == -1 && errno == ENOENT) {
191 checkUnixError(ret, "stat hugepage mountpoint failed");
192 pos->mountPoint = fs::canonical(path);
193 pos->device = st.st_dev;
201 const HugePageSizeVec& getHugePageSizes() {
202 static HugePageSizeVec sizes = readHugePageSizes();
206 const HugePageSize* getHugePageSize(size_t size) {
207 // Linear search is just fine.
208 for (auto& p : getHugePageSizes()) {
209 if (p.mountPoint.empty()) {
212 if (size == 0 || size == p.size) {
219 const HugePageSize* getHugePageSizeForDevice(dev_t device) {
220 // Linear search is just fine.
221 for (auto& p : getHugePageSizes()) {
222 if (p.mountPoint.empty()) {
225 if (device == p.device) {