/rɪˈzɔːrs ˈlɪmɪt/
noun — “the operating system’s way of saying: share your toys.”
Resource Limit is a control mechanism used by an operating system to cap how much of a system’s finite resources a process or user can consume. It exists to prevent a single program from monopolizing CPU time, memory, file handles, or other shared system assets.
A Resource Limit typically defines both soft and hard thresholds. A soft limit is adjustable by the process within allowed bounds, while a hard limit is enforced by the kernel and cannot be exceeded without elevated privileges. If a process crosses a Resource Limit, the operating system may deny further allocations, return errors, throttle execution, or terminate the process entirely.
Common Resource Limits include maximum memory usage, CPU time, number of open File Descriptors, maximum stack size, and number of child processes. These limits protect overall system stability and fairness, especially in multi-user environments.
Resource Limits are closely tied to Process Management and are often configured in a Command Line Interface environment. They are fundamental to container isolation and workload control in modern systems.
Resource Limit is like a circuit breaker for programs — trip it, and the system saves itself.
See ulimit, cgroups, Kernel, System Call.