Messages in this thread | | | Date | Mon, 20 Sep 2010 14:20:11 +1000 | From | Paul Mackerras <> | Subject | Re: [PATCH -tip -v5] irq_work: generic hard-irq context callbacks |
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On Fri, Sep 17, 2010 at 03:06:42PM +0200, Peter Zijlstra wrote:
> 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 which have soft-disabled IRQs, its ran > on the soft-enable path.
Actually these days we do it by setting the decrementer (the built-in timer facility) to generate an interrupt immediately (well, within one timebase tick, i.e. a small number of nanoseconds).
Paul.
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