lint: enable cargo fmt (sched-ext#643)

Use `cargo fmt` with a specific nightly branch in the CI to enforce formatting. Globally format these files while the diff is still small so we can stay on top of it.

Test plan:
- CI lint check passes.

.github/workflows/build-scheds.yml

@@ -2,6 +2,21 @@ name: build-scheds
 run-name: ${{ github.actor }} PR run
 on: [pull_request]
 jobs:
+  lint:
+    runs-on: ubuntu-22.04
+    steps:
+      - name: Install deps
+        run: |
+          curl https://sh.rustup.rs -sSf | RUSTUP_INIT_SKIP_PATH_CHECK=yes sh -s -- -y
+          rustup install nightly-2024-09-10
+          export PATH="~/.cargo/bin:$PATH"
+
+      - uses: actions/checkout@v4
+
+      # Lint code
+      - run: cargo +nightly-2024-09-10 fmt
+      - run: git diff --exit-code
+
   build-schedulers:
     runs-on: ubuntu-22.04
     steps:

rust/scx_loader/src/main.rs

@@ -180,8 +180,7 @@ async fn worker_loop(mut receiver: UnboundedReceiver<ScxMessage>) -> Result<()>
     // setup channel for scheduler runner
     let (runner_tx, runner_rx) = tokio::sync::mpsc::channel::<RunnerMessage>(1);
 
-    let run_sched_future =
-        tokio::spawn(async move { handle_child_process(runner_rx).await });
+    let run_sched_future = tokio::spawn(async move { handle_child_process(runner_rx).await });
 
     // prepare future for tokio
     tokio::pin!(run_sched_future);

rust/scx_rustland_core/src/alloc.rs

@@ -26,11 +26,11 @@
 // This software may be used and distributed according to the terms of the
 // GNU General Public License version 2.
 
-use std::sync::Mutex;
 use std::alloc::{GlobalAlloc, Layout};
 use std::fs::File;
 use std::io::{BufRead, BufReader, Write};
 use std::num::ParseIntError;
+use std::sync::Mutex;
 
 /// Buddy allocator
 ///

rust/scx_rustland_core/src/rustland_builder.rs

@@ -31,7 +31,10 @@ impl RustLandBuilder {
     pub fn build(&mut self) -> Result<()> {
         // Embed the BPF source files.
         let intf = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/bpf/intf.h"));
-        let skel = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/bpf/main.bpf.c"));
+        let skel = include_bytes!(concat!(
+            env!("CARGO_MANIFEST_DIR"),
+            "/assets/bpf/main.bpf.c"
+        ));
         let bpf = include_bytes!(concat!(env!("CARGO_MANIFEST_DIR"), "/assets/bpf.rs"));
 
         // Generate BPF backend code (C).

rust/scx_utils/src/bpf_builder.rs

@@ -590,11 +590,9 @@ mod tests {
 
         println!("vmlinux.h: ver={:?} sha1={:?}", &ver, &sha1,);
 
-        assert!(
-            regex::Regex::new(r"^([1-9][0-9]*\.[1-9][0-9][a-z0-9-]*)$")
-                .unwrap()
-                .is_match(&ver)
-        );
+        assert!(regex::Regex::new(r"^([1-9][0-9]*\.[1-9][0-9][a-z0-9-]*)$")
+            .unwrap()
+            .is_match(&ver));
         assert!(regex::Regex::new(r"^[0-9a-z]{12}$")
             .unwrap()
             .is_match(&sha1));

rust/scx_utils/src/cpumask.rs

@@ -95,12 +95,12 @@ impl Cpumask {
             "none" => {
                 let mask = bitvec![u64, Lsb0; 0; *NR_CPU_IDS];
                 return Ok(Self { mask });
-            },
+            }
             "all" => {
                 let mask = bitvec![u64, Lsb0; 1; *NR_CPU_IDS];
                 return Ok(Self { mask });
-            },
-            _ => {},
+            }
+            _ => {}
         }
         let hex_str = {
             let mut tmp_str = cpumask

rust/scx_utils/src/infeasible.rs

@@ -112,7 +112,7 @@
 //!```rust
 //!     use scx_utils::LoadAggregator;
 //!     use log::info;
-//! 
+//!
 //!     let mut aggregator = LoadAggregator::new(32, false);
 //!     // Create a LoadAggregator object, specifying the number of CPUs on the
 //!     // system, and whether it should only aggregate duty cycle.

rust/scx_utils/src/lib.rs

@@ -82,4 +82,3 @@ pub use log_recorder::LogRecorderBuilder;
 mod misc;
 pub use misc::monitor_stats;
 pub use misc::set_rlimit_infinity;
-

rust/scx_utils/src/misc.rs

@@ -1,10 +1,10 @@
 use anyhow::Result;
+use libc;
 use log::info;
 use scx_stats::prelude::*;
 use serde::Deserialize;
 use std::thread::sleep;
 use std::time::Duration;
-use libc;
 
 pub fn monitor_stats<T>(
     stats_args: &Vec<(String, String)>,
@@ -59,7 +59,7 @@ where
     Ok(())
 }
 
-pub fn set_rlimit_infinity(){
+pub fn set_rlimit_infinity() {
     unsafe {
         // Call setrlimit to set the locked-in-memory limit to unlimited.
         let new_rlimit = libc::rlimit {
@@ -71,4 +71,4 @@ pub fn set_rlimit_infinity(){
             panic!("setrlimit failed with error code: {}", res);
         }
     };
-}
+}

rust/scx_utils/src/topology.rs

@@ -610,7 +610,9 @@ fn create_gpus() -> BTreeMap<usize, Vec<Gpu>> {
                 let Ok(nvidia_gpu) = nvml.device_by_index(i) else {
                     continue;
                 };
-                let graphics_boost_clock = nvidia_gpu.max_customer_boost_clock(Clock::Graphics).unwrap_or(0);
+                let graphics_boost_clock = nvidia_gpu
+                    .max_customer_boost_clock(Clock::Graphics)
+                    .unwrap_or(0);
                 let sm_boost_clock = nvidia_gpu.max_customer_boost_clock(Clock::SM).unwrap_or(0);
                 let Ok(memory_info) = nvidia_gpu.memory_info() else {
                     continue;
@@ -629,8 +631,8 @@ fn create_gpus() -> BTreeMap<usize, Vec<Gpu>> {
                 let numa_path = format!("/sys/bus/pci/devices/{}/numa_node", fixed_bus_id);
                 let numa_node = read_file_usize(&Path::new(&numa_path)).unwrap_or(0);
 
-                let gpu = Gpu{
-                    index: GpuIndex::Nvidia{nvml_id: index},
+                let gpu = Gpu {
+                    index: GpuIndex::Nvidia { nvml_id: index },
                     node_id: numa_node as usize,
                     max_graphics_clock: graphics_boost_clock as usize,
                     max_sm_clock: sm_boost_clock as usize,
@@ -661,7 +663,7 @@ fn create_default_node(online_mask: &Cpumask) -> Result<Vec<Node>> {
                 node_gpus.insert(gpu.index, gpu.clone());
             }
         }
-        _ => {},
+        _ => {}
     };
 
     let mut node = Node {
@@ -708,7 +710,7 @@ fn create_numa_nodes(online_mask: &Cpumask) -> Result<Vec<Node>> {
                     node_gpus.insert(gpu.index, gpu.clone());
                 }
             }
-            _ => {},
+            _ => {}
         };
 
         let mut node = Node {

scheds/rust/scx_bpfland/src/main.rs

@@ -11,8 +11,6 @@ pub mod bpf_intf;
 pub use bpf_intf::*;
 
 mod stats;
-use stats::Metrics;
-
 use std::collections::HashMap;
 use std::ffi::c_int;
 use std::fs::File;
@@ -28,30 +26,27 @@ use anyhow::Context;
 use anyhow::Result;
 use clap::Parser;
 use crossbeam::channel::RecvTimeoutError;
-use log::info;
-
-use log::warn;
-
 use libbpf_rs::skel::OpenSkel;
 use libbpf_rs::skel::Skel;
 use libbpf_rs::skel::SkelBuilder;
 use libbpf_rs::OpenObject;
 use libbpf_rs::ProgramInput;
-
+use log::info;
+use log::warn;
 use scx_stats::prelude::*;
-
 use scx_utils::build_id;
 use scx_utils::scx_ops_attach;
 use scx_utils::scx_ops_load;
 use scx_utils::scx_ops_open;
+use scx_utils::set_rlimit_infinity;
 use scx_utils::uei_exited;
 use scx_utils::uei_report;
 use scx_utils::CoreType;
 use scx_utils::Cpumask;
 use scx_utils::Topology;
 use scx_utils::UserExitInfo;
 use scx_utils::NR_CPU_IDS;
-use scx_utils::set_rlimit_infinity;
+use stats::Metrics;
 
 const SCHEDULER_NAME: &'static str = "scx_bpfland";
 
@@ -88,7 +83,7 @@ fn get_primary_cpus(mode: Powermode) -> std::io::Result<Vec<usize>> {
 // Convert an array of CPUs to the corresponding cpumask of any arbitrary size.
 fn cpus_to_cpumask(cpus: &Vec<usize>) -> String {
     if cpus.is_empty() {
-       return String::from("none");
+        return String::from("none");
     }
 
     // Determine the maximum CPU ID to create a sufficiently large byte vector.
@@ -293,8 +288,7 @@ impl<'a> Scheduler<'a> {
 
         // Initialize the primary scheduling domain and the preferred domain.
         let energy_profile = Self::read_energy_profile();
-        if let Err(err) = Self::init_preferred_domain(&mut skel, &opts.preferred_domain)
-        {
+        if let Err(err) = Self::init_preferred_domain(&mut skel, &opts.preferred_domain) {
             warn!("failed to initialize preferred domain: error {}", err);
         }
         if let Err(err) = Self::init_energy_domain(&mut skel, &opts.primary_domain, &energy_profile)
@@ -408,17 +402,10 @@ impl<'a> Scheduler<'a> {
         Cpumask::from_str(&cpus_to_cpumask(&cpus))
     }
 
-    fn init_preferred_domain(
-        skel: &mut BpfSkel<'_>,
-        preferred_domain: &String,
-    ) -> Result<()> {
+    fn init_preferred_domain(skel: &mut BpfSkel<'_>, preferred_domain: &String) -> Result<()> {
         let domain = match preferred_domain.as_str() {
-            "auto" => {
-                Self::epp_to_cpumask(Powermode::Turbo)?
-            }
-            &_ => {
-                Cpumask::from_str(&preferred_domain)?
-            }
+            "auto" => Self::epp_to_cpumask(Powermode::Turbo)?,
+            &_ => Cpumask::from_str(&preferred_domain)?,
         };
 
         info!("preferred CPU domain = 0x{:x}", domain);
@@ -430,7 +417,10 @@ impl<'a> Scheduler<'a> {
         for cpu in 0..*NR_CPU_IDS {
             if domain.test_cpu(cpu) {
                 if let Err(err) = Self::enable_preferred_cpu(skel, cpu as i32) {
-                    warn!("failed to add CPU {} to preferred domain: error {}", cpu, err);
+                    warn!(
+                        "failed to add CPU {} to preferred domain: error {}",
+                        cpu, err
+                    );
                 }
             }
         }
@@ -444,31 +434,19 @@ impl<'a> Scheduler<'a> {
         energy_profile: &String,
     ) -> Result<()> {
         let domain = match primary_domain.as_str() {
-            "powersave" => {
-                Self::epp_to_cpumask(Powermode::Powersave)?
-            }
-            "performance" => {
-                Self::epp_to_cpumask(Powermode::Performance)?
-            }
-            "auto" => {
-                match energy_profile.as_str() {
-                    "power" | "balance_power" | "powersave" => {
-                        Self::epp_to_cpumask(Powermode::Powersave)?
-                    }
-                    "balance_performance" | "performance" => {
-                        Self::epp_to_cpumask(Powermode::Performance)?
-                    }
-                    &_ => {
-                        Self::epp_to_cpumask(Powermode::Any)?
-                    }
+            "powersave" => Self::epp_to_cpumask(Powermode::Powersave)?,
+            "performance" => Self::epp_to_cpumask(Powermode::Performance)?,
+            "auto" => match energy_profile.as_str() {
+                "power" | "balance_power" | "powersave" => {
+                    Self::epp_to_cpumask(Powermode::Powersave)?
                 }
-            }
-            "all" => {
-                Self::epp_to_cpumask(Powermode::Any)?
-            }
-            &_ => {
-                Cpumask::from_str(&primary_domain)?
-            }
+                "balance_performance" | "performance" => {
+                    Self::epp_to_cpumask(Powermode::Performance)?
+                }
+                &_ => Self::epp_to_cpumask(Powermode::Any)?,
+            },
+            "all" => Self::epp_to_cpumask(Powermode::Any)?,
+            &_ => Cpumask::from_str(&primary_domain)?,
         };
 
         info!("primary CPU domain = 0x{:x}", domain);
@@ -526,10 +504,9 @@ impl<'a> Scheduler<'a> {
                 self.energy_profile = energy_profile.clone();
 
                 if self.opts.primary_domain == "auto" {
-                    if let Err(err) = Self::init_preferred_domain(
-                        &mut self.skel,
-                        &self.opts.preferred_domain,
-                    ) {
+                    if let Err(err) =
+                        Self::init_preferred_domain(&mut self.skel, &self.opts.preferred_domain)
+                    {
                         warn!("failed to refresh preferred domain: error {}", err);
                     }
                     if let Err(err) = Self::init_energy_domain(

scheds/rust/scx_bpfland/src/stats.rs

@@ -1,14 +1,15 @@
-use anyhow::Result;
-use scx_stats::prelude::*;
-use scx_stats_derive::Stats;
-use serde::Deserialize;
-use serde::Serialize;
 use std::io::Write;
 use std::sync::atomic::AtomicBool;
 use std::sync::atomic::Ordering;
 use std::sync::Arc;
 use std::time::Duration;
 
+use anyhow::Result;
+use scx_stats::prelude::*;
+use scx_stats_derive::Stats;
+use serde::Deserialize;
+use serde::Serialize;
+
 #[derive(Clone, Debug, Default, Serialize, Deserialize, Stats)]
 #[stat(top)]
 pub struct Metrics {