Files
cgroups-rs/src/cgroup.rs
2018-08-30 13:40:15 +02:00

122 lines
4.1 KiB
Rust

//! This module handles cgroup operations. Start here!
use {CgroupPid, Resources, ControllIdentifier, Controller, Hierarchy, Subsystem};
use std::convert::From;
/// A control group is the central structure to this crate.
///
///
/// # What are control groups?
///
/// Lifting over from the Linux kernel sources:
///
/// > Control Groups provide a mechanism for aggregating/partitioning sets of
/// > tasks, and all their future children, into hierarchical groups with
/// > specialized behaviour.
///
/// This crate is an attempt at providing a Rust-native way of managing these cgroups.
pub struct Cgroup {
/// The list of subsystems that control this cgroup
subsystems: Vec<Subsystem>,
}
impl Cgroup {
/// Create this control group.
fn create(self: &Self) {
for subsystem in &self.subsystems {
subsystem.to_controller().create();
}
}
/// Create a new control group in the hierarchy `hier`, with name `path`.
///
/// Returns a handle to the control group that can be used to manipulate it.
///
/// Note that if the handle goes out of scope and is dropped, the control group is _not_
/// destroyed.
pub fn new(hier: &Hierarchy, path: String) -> Cgroup {
let mut subsystems = hier.subsystems();
subsystems = subsystems.into_iter().map(|x| x.enter(&path)).collect::<Vec<_>>();
let cg = Cgroup {
//name: path,
subsystems: subsystems,
};
cg.create();
cg
}
/// The list of subsystems that this control group supports.
pub fn subsystems(self: &Self) -> &Vec<Subsystem> {
&self.subsystems
}
/// Deletes the control group.
///
/// Note that this function makes no effort in cleaning up the descendant and the underlying
/// system call will fail if there are any descendants. Thus, one should check whether it was
/// actually removed, and remove the descendants first if not. In the future, this behavior
/// will change.
pub fn delete(self: Self) {
self.subsystems.into_iter().for_each(|sub| {
match sub {
Subsystem::Pid(pidc) => pidc.delete(),
Subsystem::Mem(c) => c.delete(),
Subsystem::CpuSet(c) => c.delete(),
Subsystem::CpuAcct(c) => c.delete(),
Subsystem::Cpu(c) => c.delete(),
Subsystem::Devices(c) => c.delete(),
Subsystem::Freezer(c) => c.delete(),
Subsystem::NetCls(c) => c.delete(),
Subsystem::BlkIo(c) => c.delete(),
Subsystem::PerfEvent(c) => c.delete(),
Subsystem::NetPrio(c) => c.delete(),
Subsystem::HugeTlb(c) => c.delete(),
Subsystem::Rdma(c) => c.delete(),
}
});
}
/// Apply a set of resource limits to the control group.
pub fn apply(self: &Self, res: &Resources) {
for subsystem in &self.subsystems {
subsystem.to_controller().apply(res);
}
}
/// Retrieve a container based on type inference.
///
/// ## Example:
///
/// ```text
/// let pids: &PidController = control_group.controller_of()
/// .expect("No pids controller attached!");
/// let cpu: &CpuController = control_group.controller_of()
/// .expect("No cpu controller attached!");
/// ```
pub fn controller_of<'a, T>(self: &'a Self) -> Option<&'a T>
where &'a T: From<&'a Subsystem>,
T: Controller + ControllIdentifier,
{
for i in &self.subsystems {
if i.to_controller().control_type() == T::controller_type() {
/*
* N.B.:
* https://play.rust-lang.org/?gist=978b2846bacebdaa00be62374f4f4334&version=stable&mode=debug&edition=2015
*/
return Some(i.into());
}
}
None
}
/// Attach a task to the control group.
pub fn add_task(self: &Self, pid: CgroupPid) {
self.subsystems().iter().for_each(|sub| sub.to_controller().add_task(&pid));
}
}