Linux memory management subsystem is responsible, as the name implies, for managing the memory in the system. This includes implementation of virtual memory and demand paging, memory allocation both for kernel internal structures and user space programs, mapping of files into processes address space and many other cool things.
Linux memory management is a complex system with many configurable settings. Most of these settings are available via /proc filesystem and can be queried and adjusted using sysctl . These APIs are described in Documentation for /proc/sys/vm/ and in man 5 proc.
Linux memory management has its own jargon and if you are not yet familiar with it, consider reading Concepts overview .
Here we document in detail how to interact with various mechanisms in the Linux memory management.