Understanding the Block Layer, Multi-Queue, and Device Mapper
Chapter 4 introduced us to the role of the block layer in the kernel. We were able to see what constitutes a block device and explored the major data structures in the block layer. This chapter will build on that knowledge as we continue understanding the block layer.
This chapter will introduce you to two major concepts: the multi-queue block I/O mechanism and the device mapper framework. The kernel’s block layer has undergone significant changes in recent years to tackle performance concerns. The introduction of the multi-queue framework was a significant milestone in this direction, as discussed in Chapter 4. Performance is a critical consideration when dealing with block devices, and the kernel has implemented various improvements to optimize disk drive performance. In Chapter 4, we looked at the request and response queue...
