Meaning
Kernel mechanism in operating systems that terminates processes when the system runs out of physical memory. The out-of-memory killer acts as a final defense against total system instability by reclaiming RAM from running applications. It selects which process to end based on a score that considers memory usage and process priority.
This prevents a single leaking application from crashing the entire server.
Resource Reclamation
Termination happens instantly once a critical memory threshold is reached. The system looks for large processes that do not have high priority or are not critical to the operating system itself. By freeing this memory, the system allows remaining services to continue functioning.
Selection Priority
Administrators can influence which processes are targeted by adjusting their score settings. Important database engines or web servers are often protected from being killed during a resource crunch. This configuration ensures that the most valuable services remain online.
System Protection
Without this mechanism, a server would likely freeze or reboot when memory is exhausted. Such an event would cause a much longer period of downtime for all hosted services. The killer provides a controlled way to handle resource exhaustion in a shared environment.
It protects the integrity of the host.
