To Make a Long Story Short
This chapter looked at the page cache and page writeback. You saw how the kernel performs all page I/O through the page cache and how writes are deferred in the page cache and eventually written out to disk via the pdflush gang of kernel threads.
Over the last few chapters, you have built a solid understanding of memory and filesystem management. Now let's segue over to the topic of modules, and see how the Linux kernel provides a modular and dynamic infrastructure for the run-time insertion and removal of kernel code.