Chapter 13. Out of Memory Management
The last aspect of the VM I am going to discuss is the Out Of Memory (OOM) manager. This intentionally is a very short chapter because it has one simple task: check if there is enough available memory to satisfy, verify that the system is truly out of memory and, if so, select a process to kill. This is a controversial part of the VM and it has been suggested that it be removed on many occasions. Regardless of whether it exists in the latest kernel, it still is a useful system to examine because it touches off a number of other subsystems.
Checking Available Memory
For certain operations, such as expanding the heap with
brk() or remapping an address space with
mremap(), the system will check if there is enough ...