OS X and iOS Kernel Programming

C H A P T E R  6

Memory Management

Memory management in the kernel is significantly more complex than it is for a user space program. A user space program typically deals with a flat linear address space and can allocate memory in more or less arbitrary blocks without worrying about the source or arrangement of this memory. It has simple interfaces that typically take a size in bytes as an argument and deliver a yay or nay result, depending on the availability of the requested memory. At worst, the consequence of a failed allocation or misuse of memory is the termination of the offending process. However, things are not as straightforward in the kernel. The kernel has to deal with multiple memory spaces, including its own, as well as the mapping ...