Linux Kernel Development, Third Edition

12. Memory Management

Memory allocation inside the kernel is not as easy as memory allocation outside the kernel. Simply put, the kernel lacks luxuries enjoyed by user-space. Unlike user-space, the kernel is not always afforded the capability to easily allocate memory. For example, the kernel cannot easily deal with memory allocation errors, and the kernel often cannot sleep. Because of these limitations, and the need for a lightweight memory allocation scheme, getting hold of memory in the kernel is more complicated than in user-space. This is not to say that, from a programmer’s point of view, kernel memory allocations are difficult—just different.

This chapter discusses the methods used to obtain memory inside the kernel. Before you can ...