cgroups_rs/fs/
hugetlb.rs

1// Copyright (c) 2018 Levente Kurusa
2// Copyright (c) 2020 Ant Group
3//
4// SPDX-License-Identifier: Apache-2.0 or MIT
5//
6
7//! This module contains the implementation of the `hugetlb` cgroup subsystem.
8//!
9//! See the Kernel's documentation for more information about this subsystem, found at:
10//!  [Documentation/cgroup-v1/hugetlb.txt](https://www.kernel.org/doc/Documentation/cgroup-v1/hugetlb.txt)
11use log::warn;
12use std::io::Write;
13use std::path::PathBuf;
14
15use crate::fs::error::ErrorKind::*;
16use crate::fs::error::*;
17use crate::fs::{flat_keyed_to_vec, read_u64_from};
18
19use crate::fs::{
20    ControllIdentifier, ControllerInternal, Controllers, HugePageResources, Resources, Subsystem,
21};
22
23/// A controller that allows controlling the `hugetlb` subsystem of a Cgroup.
24///
25/// In essence, using this controller it is possible to limit the use of hugepages in the tasks of
26/// the control group.
27#[derive(Debug, Clone)]
28pub struct HugeTlbController {
29    base: PathBuf,
30    path: PathBuf,
31    sizes: Vec<String>,
32    v2: bool,
33}
34
35impl ControllerInternal for HugeTlbController {
36    fn control_type(&self) -> Controllers {
37        Controllers::HugeTlb
38    }
39    fn get_path(&self) -> &PathBuf {
40        &self.path
41    }
42    fn get_path_mut(&mut self) -> &mut PathBuf {
43        &mut self.path
44    }
45    fn get_base(&self) -> &PathBuf {
46        &self.base
47    }
48
49    fn is_v2(&self) -> bool {
50        self.v2
51    }
52
53    fn apply(&self, res: &Resources) -> Result<()> {
54        // get the resources that apply to this controller
55        let res: &HugePageResources = &res.hugepages;
56
57        for i in &res.limits {
58            let _ = self.set_limit_in_bytes(&i.size, i.limit);
59            if self.limit_in_bytes(&i.size)? != i.limit {
60                return Err(Error::new(Other));
61            }
62        }
63
64        Ok(())
65    }
66}
67
68impl ControllIdentifier for HugeTlbController {
69    fn controller_type() -> Controllers {
70        Controllers::HugeTlb
71    }
72}
73
74impl<'a> From<&'a Subsystem> for &'a HugeTlbController {
75    fn from(sub: &'a Subsystem) -> &'a HugeTlbController {
76        unsafe {
77            match sub {
78                Subsystem::HugeTlb(c) => c,
79                _ => {
80                    assert_eq!(1, 0);
81                    let v = std::mem::MaybeUninit::uninit();
82                    v.assume_init()
83                }
84            }
85        }
86    }
87}
88
89impl HugeTlbController {
90    /// Constructs a new `HugeTlbController` with `root` serving as the root of the control group.
91    pub fn new(point: PathBuf, root: PathBuf, v2: bool) -> Self {
92        let sizes = get_hugepage_sizes();
93        Self {
94            base: root,
95            path: point,
96            sizes,
97            v2,
98        }
99    }
100
101    /// Whether the system supports `hugetlb_size` hugepages.
102    pub fn size_supported(&self, hugetlb_size: &str) -> bool {
103        for s in &self.sizes {
104            if s == hugetlb_size {
105                return true;
106            }
107        }
108        false
109    }
110
111    pub fn get_sizes(&self) -> Vec<String> {
112        self.sizes.clone()
113    }
114
115    fn failcnt_v2(&self, hugetlb_size: &str) -> Result<u64> {
116        self.open_path(&format!("hugetlb.{}.events", hugetlb_size), false)
117            .and_then(flat_keyed_to_vec)
118            .and_then(|x| {
119                if x.is_empty() {
120                    return Err(Error::from_string(format!(
121                        "get empty from hugetlb.{}.events",
122                        hugetlb_size
123                    )));
124                }
125                Ok(x[0].1 as u64)
126            })
127    }
128
129    /// Check how many times has the limit of `hugetlb_size` hugepages been hit.
130    pub fn failcnt(&self, hugetlb_size: &str) -> Result<u64> {
131        if self.v2 {
132            return self.failcnt_v2(hugetlb_size);
133        }
134        self.open_path(&format!("hugetlb.{}.failcnt", hugetlb_size), false)
135            .and_then(read_u64_from)
136    }
137
138    /// Get the limit (in bytes) of how much memory can be backed by hugepages of a certain size
139    /// (`hugetlb_size`).
140    pub fn limit_in_bytes(&self, hugetlb_size: &str) -> Result<u64> {
141        let mut file_name = format!("hugetlb.{}.limit_in_bytes", hugetlb_size);
142        if self.v2 {
143            file_name = format!("hugetlb.{}.max", hugetlb_size);
144        }
145        self.open_path(&file_name, false).and_then(read_u64_from)
146    }
147
148    /// Get the current usage of memory that is backed by hugepages of a certain size
149    /// (`hugetlb_size`).
150    pub fn usage_in_bytes(&self, hugetlb_size: &str) -> Result<u64> {
151        let mut file = format!("hugetlb.{}.usage_in_bytes", hugetlb_size);
152        if self.v2 {
153            file = format!("hugetlb.{}.current", hugetlb_size);
154        }
155        self.open_path(&file, false).and_then(read_u64_from)
156    }
157
158    /// Get the maximum observed usage of memory that is backed by hugepages of a certain size
159    /// (`hugetlb_size`).
160    pub fn max_usage_in_bytes(&self, hugetlb_size: &str) -> Result<u64> {
161        self.open_path(
162            &format!("hugetlb.{}.max_usage_in_bytes", hugetlb_size),
163            false,
164        )
165        .and_then(read_u64_from)
166    }
167
168    /// Set the limit (in bytes) of how much memory can be backed by hugepages of a certain size
169    /// (`hugetlb_size`).
170    pub fn set_limit_in_bytes(&self, hugetlb_size: &str, limit: u64) -> Result<()> {
171        let mut file_name = format!("hugetlb.{}.limit_in_bytes", hugetlb_size);
172        if self.v2 {
173            file_name = format!("hugetlb.{}.max", hugetlb_size);
174        }
175        self.open_path(&file_name, true).and_then(|mut file| {
176            file.write_all(limit.to_string().as_ref()).map_err(|e| {
177                Error::with_cause(WriteFailed(file_name.to_string(), limit.to_string()), e)
178            })
179        })
180    }
181}
182
183pub const HUGEPAGESIZE_DIR: &str = "/sys/kernel/mm/hugepages";
184use std::collections::HashMap;
185use std::fs;
186
187fn get_hugepage_sizes() -> Vec<String> {
188    let dirs = fs::read_dir(HUGEPAGESIZE_DIR);
189    if dirs.is_err() {
190        return Vec::new();
191    }
192
193    dirs.unwrap()
194        .filter_map(|e| {
195            let entry = e.map_err(|e| warn!("readdir error: {:?}", e)).ok()?;
196            let name = entry.file_name().into_string().unwrap();
197            let parts: Vec<&str> = name.split('-').collect();
198            if parts.len() != 2 {
199                return None;
200            }
201            let bmap = get_binary_size_map();
202            let size = parse_size(parts[1], &bmap)
203                .map_err(|e| warn!("parse_size error: {:?}", e))
204                .ok()?;
205            let dabbrs = get_decimal_abbrs();
206
207            Some(custom_size(size as f64, 1024.0, &dabbrs))
208        })
209        .collect()
210}
211
212pub const KB: u128 = 1000;
213pub const MB: u128 = 1000 * KB;
214pub const GB: u128 = 1000 * MB;
215pub const TB: u128 = 1000 * GB;
216pub const PB: u128 = 1000 * TB;
217
218#[allow(non_upper_case_globals)]
219pub const KiB: u128 = 1024;
220#[allow(non_upper_case_globals)]
221pub const MiB: u128 = 1024 * KiB;
222#[allow(non_upper_case_globals)]
223pub const GiB: u128 = 1024 * MiB;
224#[allow(non_upper_case_globals)]
225pub const TiB: u128 = 1024 * GiB;
226#[allow(non_upper_case_globals)]
227pub const PiB: u128 = 1024 * TiB;
228
229pub fn get_binary_size_map() -> HashMap<String, u128> {
230    let mut m = HashMap::new();
231    m.insert("k".to_string(), KiB);
232    m.insert("m".to_string(), MiB);
233    m.insert("g".to_string(), GiB);
234    m.insert("t".to_string(), TiB);
235    m.insert("p".to_string(), PiB);
236    m
237}
238
239pub fn get_decimal_size_map() -> HashMap<String, u128> {
240    let mut m = HashMap::new();
241    m.insert("k".to_string(), KB);
242    m.insert("m".to_string(), MB);
243    m.insert("g".to_string(), GB);
244    m.insert("t".to_string(), TB);
245    m.insert("p".to_string(), PB);
246    m
247}
248
249pub fn get_decimal_abbrs() -> Vec<String> {
250    let m = vec![
251        "B".to_string(),
252        "KB".to_string(),
253        "MB".to_string(),
254        "GB".to_string(),
255        "TB".to_string(),
256        "PB".to_string(),
257        "EB".to_string(),
258        "ZB".to_string(),
259        "YB".to_string(),
260    ];
261    m
262}
263
264fn parse_size(s: &str, m: &HashMap<String, u128>) -> Result<u128> {
265    // Remove leading/trailing whitespace.
266    let s = s.trim();
267
268    // Remove an optional trailing 'b' or 'B'
269    let s = if let Some(stripped) = s.strip_suffix('b').or_else(|| s.strip_suffix('B')) {
270        stripped
271    } else {
272        s
273    };
274
275    // Ensure that the string is not empty after stripping.
276    if s.is_empty() {
277        return Err(Error::new(InvalidBytesSize));
278    }
279
280    // The last character should be the multiplier letter.
281    let last_char = s.chars().last().unwrap();
282    if !"kKmMgGtTpP".contains(last_char) {
283        return Err(Error::new(InvalidBytesSize));
284    }
285
286    // The numeric part is everything before the multiplier letter.
287    let num_part = &s[..s.len() - last_char.len_utf8()];
288    if num_part.trim().is_empty() {
289        return Err(Error::new(InvalidBytesSize));
290    }
291
292    // Parse the numeric part into a u128.
293    let number: u128 = num_part
294        .trim()
295        .parse()
296        .map_err(|_| Error::new(InvalidBytesSize))?;
297
298    // Look up the multiplier in the provided HashMap.
299    let multiplier_key = last_char.to_string();
300    let multiplier = m
301        .get(&multiplier_key)
302        .ok_or_else(|| Error::new(InvalidBytesSize))?;
303
304    Ok(number * multiplier)
305}
306
307fn custom_size(mut size: f64, base: f64, m: &[String]) -> String {
308    let mut i = 0;
309    while size >= base && i < m.len() - 1 {
310        size /= base;
311        i += 1;
312    }
313
314    format!("{}{}", size, m[i].as_str())
315}
316
317#[cfg(test)]
318mod tests {
319    use super::*;
320
321    #[test]
322    fn test_binary_size_valid() {
323        let m = get_binary_size_map();
324        // Valid inputs must include a multiplier letter.
325        assert_eq!(parse_size("1k", &m).unwrap(), KiB);
326        assert_eq!(parse_size("2m", &m).unwrap(), 2 * MiB);
327        assert_eq!(parse_size("3g", &m).unwrap(), 3 * GiB);
328        assert_eq!(parse_size("4t", &m).unwrap(), 4 * TiB);
329        assert_eq!(parse_size("5p", &m).unwrap(), 5 * PiB);
330    }
331
332    #[test]
333    fn test_decimal_size_valid() {
334        let m = get_decimal_size_map();
335        assert_eq!(parse_size("1k", &m).unwrap(), KB);
336        assert_eq!(parse_size("2m", &m).unwrap(), 2 * MB);
337        assert_eq!(parse_size("3g", &m).unwrap(), 3 * GB);
338        assert_eq!(parse_size("4t", &m).unwrap(), 4 * TB);
339        assert_eq!(parse_size("5p", &m).unwrap(), 5 * PB);
340    }
341
342    #[test]
343    fn test_trailing_b_suffix() {
344        let m = get_binary_size_map();
345        // Trailing 'b' or 'B' should be accepted.
346        assert_eq!(parse_size("1kb", &m).unwrap(), KiB);
347        assert_eq!(parse_size("2mB", &m).unwrap(), 2 * MiB);
348    }
349
350    #[test]
351    fn test_invalid_inputs() {
352        let m = get_binary_size_map();
353        // Missing multiplier letter results in error.
354        assert!(parse_size("1", &m).is_err());
355        // Invalid multiplier letter.
356        assert!(parse_size("10x", &m).is_err());
357        // Non-numeric input.
358        assert!(parse_size("abc", &m).is_err());
359        // Only multiplier letter with no number.
360        assert!(parse_size("k", &m).is_err());
361        // Number with an invalid trailing character.
362        assert!(parse_size("123z", &m).is_err());
363    }
364
365    #[test]
366    fn test_uppercase_multiplier_fails() {
367        let m = get_binary_size_map();
368        // Although the regex matches uppercase letters, the provided map only contains lowercase keys.
369        // Therefore, "1K" does not match any key and should produce an error.
370        assert!(parse_size("1K", &m).is_err());
371    }
372}
cgroups_rs/fs/hugetlb.rs

cgroups_rs/fs/
hugetlb.rs
