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    SubjectRe: Tasklet usage?
    Pierre Ossman wrote:
    > My driver needs to spend a lot of time inside the interrupt handler
    > (draining a FIFO). I suspect this might cause problems blocking other
    > interrupt handlers so I was thinking about moving this into a tasklet.
    > Not being to familiar with tasklets, a few questions pop up.
    > * Will a tasklet scheduled from the interrupt handler be executed as
    > soon as interrupt handling is done?
    I don't _think_ they are guaranteed to be executed immediately after the
    interrupt handler top half is complete, but they will execute before
    the next return to user space (read: they will complete before user
    processes run again).

    > * Can tasklets be preempted?
    A tasklet can get preempted by a hard interrupt, but tasklets run in
    interrupt context, so don't do anything in a tasklet that can call schedule.
    > * If a tasklet gets scheduled while running, will it be executed once
    > more? (Needed if I get another FIFO interrupt while the tasklet is just
    > exiting).
    IIRC, a tasklet will execute once for every time tasklet_schedule is called.


    *Neil Horman
    *Software Engineer
    *Red Hat, Inc.
    *gpg keyid: 1024D / 0x92A74FA1
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