[$] Controlling block-I/O latency

<p>Chris Mason and Josef Bacik led a brief discussion on the block-I/Ocontroller for control groups (cgroups) in the filesystem track at the 2018 LinuxStorage, Filesystem, and Memory-Management Summit. Mostly they were justaiming to get feedback on the approach they have taken. They are trying toaddress the needs of their employer, Facebook, with regard to the latencyof I/O operations.