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    SubjectRe: The difference of request dir between AS and Deadline I/O scheduler?
    On Mon, Mar 02 2009, ???? wrote:
    > Hi,
    >
    > I'm little confused about the defination of request dir in AS and
    > Deadline I/O scheduler.
    > In AS, the request dir is defined by wheher it's sync:
    >
    > data_dir = rq_is_sync(rq);
    >
    > But in Deadline, the requests are grouped by read and write.
    >
    > Why is there the difference since AS is an extension of Deadline?
    > what's the consideration?

    Because AS uses the sync vs async distinction to decide whether to
    anticipate a new request from that process. 'sync' is then reads or sync
    writes, whereas deadline does not distinguish between sync and async
    writes.

    --
    Jens Axboe



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