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 – the memory alloca­tion/free work for those objects are much quicker and thus overall performance receives a boost.

So, think about this: what if we’re writing a driver and within it, we notice that 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. Some good news: the Linux kernel sufficiently exposes the slab layer API to us, the module/driver authors, allowing us to create custom slab caches. In this section, you’ll learn how you can leverage this powerful feature.

Creating and using a custom slab cache within a kernel module

In this section, we will create, use, and subsequently...