Reverse Map Virtual Memory (rmap VM)

Virtual memory (VM) allows each process to exist in its own memory space. Every time a process attempts to access a portion of memory, the kernel translates the memory location from an address in the process’s own address space to one in real memory. The reverse map allows the kernel to perform this process in reverse: Given a location in physical memory, the kernel can determine which process owns it. The reverse map allows pages to be unallocated quickly, giving the system more free memory, fewer page faults, and less overhead when quitting a program.