vendor/rustix-0.36.5/src/process/sched.rs

   1 use crate::process::Pid;
   2 use crate::{backend, io};
   3
   4 /// `CpuSet` represents a bit-mask of CPUs.
   5 ///
   6 /// `CpuSet`s are used by [`sched_setaffinity`] and [`sched_getaffinity`], for
   7 /// example.
   8 ///
   9 /// # References
  10 ///  - [Linux]
  11 ///
  12 /// [Linux]: https://man7.org/linux/man-pages/man3/CPU_SET.3.html
  13 /// [`sched_setaffinity`]: crate::process::sched_setaffinity
  14 /// [`sched_getaffinity`]: crate::process::sched_getaffinity
  15 #[repr(C)]
  16 #[derive(Clone, Copy, Debug, Eq, Hash, PartialEq)]
  17 pub struct CpuSet {
  18     cpu_set: backend::process::types::RawCpuSet,
  19 }
  20
  21 impl CpuSet {
  22     /// The maximum number of CPU in `CpuSet`.
  23     pub const MAX_CPU: usize = backend::process::types::CPU_SETSIZE;
  24
  25     /// Create a new and empty `CpuSet`.
  26     #[inline]
  27     pub fn new() -> Self {
  28         Self {
  29             cpu_set: backend::process::types::raw_cpu_set_new(),
  30         }
  31     }
  32
  33     /// Test to see if a CPU is in the `CpuSet`.
  34     ///
  35     /// `field` is the CPU id to test.
  36     #[inline]
  37     pub fn is_set(&self, field: usize) -> bool {
  38         backend::process::cpu_set::CPU_ISSET(field, &self.cpu_set)
  39     }
  40
  41     /// Add a CPU to `CpuSet`.
  42     ///
  43     /// `field` is the CPU id to add.
  44     #[inline]
  45     pub fn set(&mut self, field: usize) {
  46         backend::process::cpu_set::CPU_SET(field, &mut self.cpu_set)
  47     }
  48
  49     /// Remove a CPU from `CpuSet`.
  50     ///
  51     /// `field` is the CPU id to remove.
  52     #[inline]
  53     pub fn unset(&mut self, field: usize) {
  54         backend::process::cpu_set::CPU_CLR(field, &mut self.cpu_set)
  55     }
  56
  57     /// Count the number of CPUs set in the `CpuSet`.
  58     #[cfg(any(target_os = "android", target_os = "linux"))]
  59     #[inline]
  60     pub fn count(&self) -> u32 {
  61         backend::process::cpu_set::CPU_COUNT(&self.cpu_set)
  62     }
  63
  64     /// Zeroes the `CpuSet`.
  65     #[inline]
  66     pub fn clear(&mut self) {
  67         backend::process::cpu_set::CPU_ZERO(&mut self.cpu_set)
  68     }
  69 }
  70
  71 impl Default for CpuSet {
  72     #[inline]
  73     fn default() -> Self {
  74         Self::new()
  75     }
  76 }
  77
  78 /// `sched_setaffinity(pid, cpuset)`—Set a thread's CPU affinity mask.
  79 ///
  80 /// `pid` is the thread ID to update. If pid is `None`, then the current thread
  81 /// is updated.
  82 ///
  83 /// The `CpuSet` argument specifies the set of CPUs on which the thread will
  84 /// be eligible to run.
  85 ///
  86 /// # References
  87 ///  - [Linux]
  88 ///
  89 /// [Linux]: https://man7.org/linux/man-pages/man2/sched_setaffinity.2.html
  90 #[inline]
  91 pub fn sched_setaffinity(pid: Option<Pid>, cpuset: &CpuSet) -> io::Result<()> {
  92     backend::process::syscalls::sched_setaffinity(pid, &cpuset.cpu_set)
  93 }
  94
  95 /// `sched_getaffinity(pid)`—Get a thread's CPU affinity mask.
  96 ///
  97 /// `pid` is the thread ID to check. If pid is `None`, then the current thread
  98 /// is checked.
  99 ///
 100 /// Returns the set of CPUs on which the thread is eligible to run.
 101 ///
 102 /// # References
 103 ///  - [Linux]
 104 ///
 105 /// [Linux]: https://man7.org/linux/man-pages/man2/sched_getaffinity.2.html
 106 #[inline]
 107 pub fn sched_getaffinity(pid: Option<Pid>) -> io::Result<CpuSet> {
 108     let mut cpuset = CpuSet::new();
 109     backend::process::syscalls::sched_getaffinity(pid, &mut cpuset.cpu_set).and(Ok(cpuset))
 110 }