cgroups-rs/src/perf_event.rs

//! This module contains the implementation of the `perf_event` cgroup subsystem.
//! 
//! See the Kernel's documentation for more information about this subsystem, found at:
//!  [tools/perf/Documentation/perf-record.txt](https://raw.githubusercontent.com/torvalds/linux/master/tools/perf/Documentation/perf-record.txt)
use std::path::PathBuf;

use {Controllers, Controller, Resources, ControllIdentifier, Subsystem};

/// A controller that allows controlling the `perf_event` subsystem of a Cgroup.
///
/// In essence, when processes belong to the same `perf_event` controller, they can be monitored
/// together using the `perf` performance monitoring and reporting tool.
#[derive(Debug, Clone)]
pub struct PerfEventController {
    base: PathBuf,
    path: PathBuf,
}

impl Controller for PerfEventController {
    fn control_type(self: &Self) -> Controllers { Controllers::PerfEvent }
    fn get_path<'a>(self: &'a Self) -> &'a PathBuf { &self.path }
    fn get_path_mut<'a>(self: &'a mut Self) -> &'a mut PathBuf { &mut self.path }
    fn get_base<'a>(self: &'a Self) -> &'a PathBuf { &self.base }

    fn apply(self: &Self, _res: &Resources) {
    }
}

impl ControllIdentifier for PerfEventController {
    fn controller_type() -> Controllers {
        Controllers::PerfEvent
    }
}

impl<'a> From<&'a Subsystem> for &'a PerfEventController {
    fn from(sub: &'a Subsystem) -> &'a PerfEventController {
        unsafe {
            match sub {
                Subsystem::PerfEvent(c) => c,
                _ => {
                    assert_eq!(1, 0);
                    ::std::mem::uninitialized()
                },
            }
        }
    }
}

impl PerfEventController {
    /// Constructs a new `PerfEventController` with `oroot` serving as the root of the control group.
    pub fn new(oroot: PathBuf) -> Self {
        let mut root = oroot;
        root.push(Self::controller_type().to_string());
        Self {
            base: root.clone(),
            path: root,
        }
    }
}