[$] The block I/O latency controller

Large data centers routinely use control groups to balance the use of theavailable computing resources among competing users. Block I/O bandwidthcan be one of the most important resources for certain types of workloads,but the kernel's I/O controller is not a complete solution to the problem.The upcoming block I/O latency controllerlooks set to fill that gap in the near future, at least for some classes ofusers.