[Etzos]

I don't know a whole lot about this area either, but it looks more like this is allowing for the queueing system used by each block device to offer a choice to the user (via sysfs). The user can set it to use this new mechanism if they want which should have significant speed gains for devices which have little latency between a request for a read/write and the data being actually read or written.

In short: I don't think this has anything to do with programs at all. This looks like it has nothing to do with userspace and I believe it's just the locking mechanism on the device.