From c9e55ac2e06c2c80ceff7777d9b8672bbba4ddc8 Mon Sep 17 00:00:00 2001 From: Furisto <24721048+Furisto@users.noreply.github.com> Date: Sun, 5 Sep 2021 15:26:52 +0200 Subject: [PATCH] Rework cgroup detection --- cgroups/src/common.rs | 128 +++++++++++++++++++----------------------- src/commands/info.rs | 5 +- 2 files changed, 61 insertions(+), 72 deletions(-) diff --git a/cgroups/src/common.rs b/cgroups/src/common.rs index fefc36730..c4c1b0607 100644 --- a/cgroups/src/common.rs +++ b/cgroups/src/common.rs @@ -1,5 +1,4 @@ use std::{ - env, fmt::{Debug, Display}, fs::{self, File}, io::{BufRead, BufReader, Write}, @@ -7,9 +6,11 @@ use std::{ }; use anyhow::{bail, Context, Result}; -use nix::unistd::Pid; +use nix::{ + sys::statfs::{statfs, CGROUP2_SUPER_MAGIC, TMPFS_MAGIC}, + unistd::Pid, +}; use oci_spec::{FreezerState, LinuxDevice, LinuxDeviceCgroup, LinuxDeviceType, LinuxResources}; -use procfs::process::Process; #[cfg(feature = "systemd_cgroups")] use systemd::daemon::booted; #[cfg(not(feature = "systemd_cgroups"))] @@ -41,16 +42,18 @@ pub trait CgroupManager { } #[derive(Debug)] -pub enum Cgroup { - V1, - V2, +pub enum CgroupSetup { + Hybrid, + Legacy, + Unified, } -impl Display for Cgroup { +impl Display for CgroupSetup { fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { - let print = match *self { - Cgroup::V1 => "v1", - Cgroup::V2 => "v2", + let print = match self { + CgroupSetup::Hybrid => "hybrid", + CgroupSetup::Legacy => "legacy", + CgroupSetup::Unified => "unified", }; write!(f, "{}", print) @@ -91,92 +94,79 @@ pub fn read_cgroup_file>(path: P) -> Result { fs::read_to_string(path).with_context(|| format!("failed to open {:?}", path)) } -pub fn get_supported_cgroup_fs() -> Result> { - let cgroup_mount = Process::myself()? - .mountinfo()? - .into_iter() - .find(|m| m.fs_type == "cgroup"); - - let cgroup2_mount = Process::myself()? - .mountinfo()? - .into_iter() - .find(|m| m.fs_type == "cgroup2"); +/// Determines the cgroup setup of the system. Systems typically have one of +/// three setups: +/// - Unified: Pure cgroup v2 system. +/// - Legacy: Pure cgroup v1 system. +/// - Hybrid: Hybrid is basically a cgroup v1 system, except for +/// an additional unified hierarchy which doesn't have any +/// controllers attached. Resource control can purely be achieved +/// through the cgroup v1 hierarchy, not through the cgroup v2 hierarchy. +pub fn get_cgroup_setup() -> Result { + let default_root = Path::new(DEFAULT_CGROUP_ROOT); + match default_root.exists() { + true => { + // If the filesystem is of type cgroup2, the system is in unified mode. + // If the filesystem is tmpfs instead the system is either in legacy or + // hybrid mode. If a cgroup2 filesystem has been mounted under the "unified" + // folder we are in hybrid mode, otherwise we are in legacy mode. + let stat = statfs(default_root).with_context(|| { + format!( + "failed to stat default cgroup root {}", + &default_root.display() + ) + })?; + if stat.filesystem_type() == CGROUP2_SUPER_MAGIC { + return Ok(CgroupSetup::Unified); + } - let mut cgroups = vec![]; - if cgroup_mount.is_some() { - cgroups.push(Cgroup::V1); - } + if stat.filesystem_type() == TMPFS_MAGIC { + let unified = Path::new("/sys/fs/cgroup/unified"); + if Path::new(unified).exists() { + let stat = statfs(unified) + .with_context(|| format!("failed to stat {}", unified.display()))?; + if stat.filesystem_type() == CGROUP2_SUPER_MAGIC { + return Ok(CgroupSetup::Hybrid); + } + } - if cgroup2_mount.is_some() { - cgroups.push(Cgroup::V2); + return Ok(CgroupSetup::Legacy); + } + } + false => bail!("non default cgroup root not supported"), } - Ok(cgroups) + bail!("failed to detect cgroup setup"); } pub fn create_cgroup_manager>( cgroup_path: P, systemd_cgroup: bool, ) -> Result> { - let cgroup_mount = Process::myself()? - .mountinfo()? - .into_iter() - .find(|m| m.fs_type == "cgroup"); + let cgroup_setup = get_cgroup_setup()?; - let cgroup2_mount = Process::myself()? - .mountinfo()? - .into_iter() - .find(|m| m.fs_type == "cgroup2"); - - match (cgroup_mount, cgroup2_mount) { - (Some(_), None) => { + match cgroup_setup { + CgroupSetup::Legacy | CgroupSetup::Hybrid => { log::info!("cgroup manager V1 will be used"); Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?)) } - (None, Some(cgroup2)) => { - log::info!("cgroup manager V2 will be used"); + CgroupSetup::Unified => { if systemd_cgroup { if !booted()? { bail!("systemd cgroup flag passed, but systemd support for managing cgroups is not available"); } log::info!("systemd cgroup manager will be used"); return Ok(Box::new(v2::SystemDCGroupManager::new( - cgroup2.mount_point, + DEFAULT_CGROUP_ROOT.into(), cgroup_path.into(), )?)); } + log::info!("cgroup manager V2 will be used"); Ok(Box::new(v2::manager::Manager::new( - cgroup2.mount_point, + DEFAULT_CGROUP_ROOT.into(), cgroup_path.into(), )?)) } - (Some(_), Some(cgroup2)) => { - let cgroup_override = env::var("YOUKI_PREFER_CGROUPV2"); - match cgroup_override { - Ok(v) if v == "true" => { - log::info!("cgroup manager V2 will be used"); - if systemd_cgroup { - if !booted()? { - bail!("systemd cgroup flag passed, but systemd support for managing cgroups is not available"); - } - log::info!("systemd cgroup manager will be used"); - return Ok(Box::new(v2::SystemDCGroupManager::new( - cgroup2.mount_point, - cgroup_path.into(), - )?)); - } - Ok(Box::new(v2::manager::Manager::new( - cgroup2.mount_point, - cgroup_path.into(), - )?)) - } - _ => { - log::info!("cgroup manager V1 will be used"); - Ok(Box::new(v1::manager::Manager::new(cgroup_path.into())?)) - } - } - } - _ => bail!("could not find cgroup filesystem"), } } diff --git a/src/commands/info.rs b/src/commands/info.rs index d29411877..1c9186b02 100644 --- a/src/commands/info.rs +++ b/src/commands/info.rs @@ -106,9 +106,8 @@ pub fn print_hardware() { /// Print cgroups info of system pub fn print_cgroups() { - if let Ok(cgroup_fs) = cgroups::common::get_supported_cgroup_fs() { - let cgroup_fs: Vec = cgroup_fs.into_iter().map(|c| c.to_string()).collect(); - println!("{:<18}{}", "Cgroup version", cgroup_fs.join(" and ")); + if let Ok(cgroup_setup) = cgroups::common::get_cgroup_setup() { + println!("{:<18}{}", "Cgroup setup", cgroup_setup); } println!("Cgroup mounts");