Do not allow a user level process from consuming all memory, crippling system

Currently, if a user level process maps memory to the point that the OS is starved for memory, Linux will begin to terminate system level processes (like daemons) in a vain attempt to keep running, and to the point that the system becomes unusable (for example, killing 'sshd' so the system is inaccessible).

The kernel should deny memory requests by user level processes that exceed a calculated hard limit, thus preserving memory for OS level processes. This segmentation of the system's memory into a user space and system space will help the survivability of a system in the face of a runaway or poorly behaved user level process.