KernelParameter

KernelParameter is a configurable value that influences the behavior of an operating system kernel. These parameters enable fine-tuning of core subsystems such as memory management, process scheduling, device I/O, networking, and security. They are used to optimize performance, stabilize systems, or enable debugging features without rebuilding the kernel.

Most kernel parameters apply at the kernel level and are exposed through special interfaces. In Linux, for example, values live in the /proc/sys virtual file system and can also be supplied as boot-time arguments to the kernel on the command line. Some parameters are static after boot, while others can be changed at runtime.

Configuration can be made persistent by writing values to configuration files, such as /etc/sysctl.conf or files under /etc/sysctl.d/. Runtime changes are commonly applied with commands such as sysctl -w or by writing directly to the /proc/sys path. Boot parameters are typically set via the bootloader configuration (for instance, GRUB) with a parameter=value syntax.

Common Linux kernel parameters include vm.swappiness (memory swapping tendency), vm.dirty_ratio (dirty page writeback threshold), net.ipv4.ip_forward (packet forwarding), fs.file-max (maximum open files), and kernel.core_pattern (core dump naming).

Changing kernel parameters can affect stability, performance, and security. Some changes require a restart or careful validation, and different kernel versions may provide different parameter sets or ranges. It is advisable to consult documentation for the specific kernel version in use and to test changes in a controlled environment.

See also: sysctl, kernel boot parameters, /proc/sys, /sys, kernel parameters in other operating systems.