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    SubjectRe: [RFC][PATCH] irq_work
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    On Thu, 2010-06-24 at 14:58 +0800, Peter Zijlstra wrote:
    > On Thu, 2010-06-24 at 14:50 +0800, Huang Ying wrote:
    > > On Thu, 2010-06-24 at 14:47 +0800, Peter Zijlstra wrote:
    > > > On Thu, 2010-06-24 at 14:43 +0800, Huang Ying wrote:
    > > > > Hi, Peter,
    > > >
    > > > > I fact I uses exactly the similar method in my patches, just trigger it
    > > > > with soft_irq instead of IRQ. Please take a look at
    > > > > nmi_return_notifier_schedule in
    > > >
    > > > But then why still use softirq? Once you have this its completely
    > > > useless.
    > >
    > > Some systems have no self interrupt, for example the system without
    > > APIC. We need to provide a fallback for them. soft_irq can help here.
    >
    > So there's systems that don't have self-ipi but do have NMI context?

    Yes. NMI is there from 8259 age.

    > Can't we run the callbacks from the tick or something for such legacy
    > muck? I really don't like the whole softirq mess.

    That is possible. But in NO_HZ system, we have no tick to rely on.
    soft_irq is better here, because it will be triggered for any interrupt.

    Best Regards,
    Huang Ying



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