Conclusion

In this suspense-laden chapter, we looked at the abstraction of virtual memory provided to each process. We looked at how the kernel represents the process address space (via struct mm_struct) and how the kernel represents regions of memory within that space (struct vm_area_struct). We covered how the kernel creates (via mmap()) and destroys (via munmap()) these memory regions. Finally, we covered page tables. Because Linux is a virtual memorybased operating system, these concepts are essential to its operation and process model.

The next chapter covers the page cache, a general in-memory data cache used to fulfill all page I/O, and how the kernel performs page-based data writeback. Hold on!