fix: set M_MMAP_THRESHOLD to prevent glibc memory fragmentation

cosmic-settings/src/main.rs

@@ -28,6 +28,25 @@ use ron::error::SpannedError;
 use serde::{Deserialize, Serialize};
 use tracing_subscriber::prelude::*;
 
+/// Access glibc malloc tunables.
+#[cfg(target_env = "gnu")]
+mod malloc {
+    use std::os::raw::c_int;
+
+    const M_MMAP_THRESHOLD: c_int = -3;
+
+    extern "C" {
+        fn mallopt(param: c_int, value: c_int) -> c_int;
+    }
+
+    /// Prevents glibc from hoarding memory via memory fragmentation.
+    pub fn limit_mmap_threshold() {
+        unsafe {
+            mallopt(M_MMAP_THRESHOLD, 65536);
+        }
+    }
+}
+
 #[derive(Parser, Debug, Serialize, Deserialize, Clone)]
 #[command(author, version, about, long_about = None)]
 #[command(propagate_version = true)]
@@ -140,6 +159,9 @@ impl CosmicFlags for Args {
 ///
 /// Returns error if iced fails to run the application.
 pub fn main() -> color_eyre::Result<()> {
+    #[cfg(target_env = "gnu")]
+    malloc::limit_mmap_threshold();
+
     color_eyre::install()?;
 
     if std::env::var("RUST_SPANTRACE").is_err() {