Set read ahead cache for better microSD read performance

src/freedombone-utils-setup

@@ -794,6 +794,18 @@ function install_shellcheck {
     apt-get -yq install shellcheck
 }
 
+function set_read_ahead {
+    # Setting this can significantly improve microSD read performance
+    read_ahead="$1"
+    if [ ! "$read_ahead" ]; then
+        read_ahead=4096
+    fi
+    if [ ! -f /sys/devices/virtual/bdi/179:0/read_ahead_kb ]; then
+        return
+    fi
+    echo -n "$read_ahead" > /sys/devices/virtual/bdi/179:0/read_ahead_kb
+}
+
 function setup_utils {
     read_config_param "PROJECT_REPO"
     write_config_param "PROJECT_REPO" "$PROJECT_REPO"
@@ -816,6 +828,9 @@ function setup_utils {
     function_check separate_tmp_filesystem
     separate_tmp_filesystem 150
 
+    function_check set_read_ahead
+    set_read_ahead 4096
+
     function_check proc_filesystem_settings
     proc_filesystem_settings