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    irq_work: Add generic hardirq context callbacks · e360adbe
    Peter Zijlstra 提交于
    Provide a mechanism that allows running code in IRQ context. It is
    most useful for NMI code that needs to interact with the rest of the
    system -- like wakeup a task to drain buffers.
    
    Perf currently has such a mechanism, so extract that and provide it as
    a generic feature, independent of perf so that others may also
    benefit.
    
    The IRQ context callback is generated through self-IPIs where
    possible, or on architectures like powerpc the decrementer (the
    built-in timer facility) is set to generate an interrupt immediately.
    
    Architectures that don't have anything like this get to do with a
    callback from the timer tick. These architectures can call
    irq_work_run() at the tail of any IRQ handlers that might enqueue such
    work (like the perf IRQ handler) to avoid undue latencies in
    processing the work.
    Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
    Acked-by: NKyle McMartin <kyle@mcmartin.ca>
    Acked-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
    [ various fixes ]
    Signed-off-by: NHuang Ying <ying.huang@intel.com>
    LKML-Reference: <1287036094.7768.291.camel@yhuang-dev>
    Signed-off-by: NIngo Molnar <mingo@elte.hu>
    e360adbe
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