Creating a custom slab cache

As explained in detail in the previous chapter, a key design concept behind slab caches is the powerful idea of object caching. By caching frequently used objects – data structures, really – performance receives a boost. So, think about this: what if we're writing a driver, and in that driver, a certain data structure (an object) is very frequently allocated and freed? Normally, we would use the usual kzalloc() (or kmalloc()) followed by the kfree() APIs to allocate and free this object. The good news, though: the Linux kernel sufficiently exposes the slab layer API to us as module authors, allowing us to create our own custom slab caches. In this section, you'll learn how you can leverage this powerful feature.