I/O scheduler (aka dsched)

[Matthew Dillon]

    This looks very cool.  I will dive into it as soon as the release
    cycle is over.  Once it gets stabilized we will be able to integrate
    it into the hammer cleanup code to reduce its impact on the system.

    Have you done any testing against typically expensive HAMMER operations
    such as rm -rf's and tar extractions?  Those might be harder to schedule
    since so much of the work gets shoved over to the HAMMER flusher
    threads.

						-Matt