The numactl repository provides a set of userspace tools and a shared library (libnuma) for controlling Non-Uniform Memory Access (NUMA) memory allocation and CPU binding policies on Linux systems. The core tool, `numactl`, allows launching processes with specified memory placement policies (interleave, bind, preferred, local, weighted interleave) and CPU affinity. The library `libnuma` exposes a C API for applications to set these policies programmatically, interacting with the Linux kernel via system calls (mbind, set_mempolicy, etc.) and reading topology information from sysfs. Additional utilities include `numastat` for per-node memory statistics display, `memhog` for memory allocation testing, `migratepages` for manual page migration, and `numademo` for benchmarking NUMA performance characteristics. The codebase is written in C with autotools build system, maintains API/ABI compatibility through symbol versioning, and includes regression tests and fuzzing harnesses. It is the de facto standard library for NUMA policy management on Linux.