The Budget Fair Queueing I/O scheduler is a proportional-share storage-I/O scheduler with support for hierarchical scheduling using a cgroups interface. BFQ aims to provide low-latency for interactive applications, low-latency for soft real-time applications, high throughput, and strong fairness guarantees. Those unfamiliar with the BFQ scheduler can find more details via this web-page.
No official message has yet to be volleyed on the Linux kernel mailing list with the patches for review by kernel developers, but in announcing BFQ-v7r2 on the BFQ-iosched mailing list, one of the developers mentions, "it seems that we have found the time to pack BFQ for submission to [the Linux kernel mailing list]."
Right now the Budget Fair Queueing are breaking up the patches and cleaning them up prior to submitted them for review and hopeful inclusion into the mainline Linux kernel. Unless the patches were submitted very soon and the review period goes remarkably well, BFQ is likely not on the table for the Linux 3.15 kernel merge window, but we can start hoping otherwise for Linux 3.16.