cpu: create get_logical_core_count

src/cpu.rs

@@ -20,16 +20,13 @@ fn write_sysfs_value(path: impl AsRef<Path>, value: &str) -> Result<()> {
     })
 }
 
-fn for_each_cpu_core<F>(mut action: F) -> Result<()>
-where
-    F: FnMut(u32) -> Result<()>,
-{
+pub fn get_logical_core_count() -> Result<u32> {
     // Using num_cpus::get() for a reliable count of logical cores accessible.
     // The monitor module's get_logical_core_count might be more specific to cpufreq-capable cores,
     // but for applying settings, we might want to iterate over all reported by OS.
     // However, settings usually apply to cores with cpufreq.
     // Let's use a similar discovery to monitor's get_logical_core_count
-    let mut cores_to_act_on = Vec::new();
+    let mut num_cores: u32 = 0;
     let path = Path::new("/sys/devices/system/cpu");
     if !path.exists() {
         return Err(ControlError::NotSupported(format!(
@@ -59,20 +56,25 @@ where
             continue;
         }
 
-        if let Ok(core_id) = name[3..].parse::<u32>() {
-            cores_to_act_on.push(core_id);
+        if name[3..].parse::<u32>().is_ok() {
+            num_cores += 1;
         }
     }
-    if cores_to_act_on.is_empty() {
+    if num_cores == 0 {
         // Fallback if sysfs iteration above fails to find any cpufreq cores
-        #[allow(clippy::cast_possible_truncation)]
-        let num_cores = num_cpus::get() as u32;
-        for core_id in 0..num_cores {
-            cores_to_act_on.push(core_id);
-        }
+        num_cores = num_cpus::get() as u32;
     }
 
-    for core_id in cores_to_act_on {
+    Ok(num_cores)
+}
+
+fn for_each_cpu_core<F>(mut action: F) -> Result<()>
+where
+    F: FnMut(u32) -> Result<()>,
+{
+    let num_cores: u32 = get_logical_core_count()?;
+
+    for core_id in 0u32..num_cores {
         action(core_id)?;
     }
     Ok(())