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    SubjectRe: [PATCH] KVM: Use IRQF_ONESHOT for assigned device MSI interrupts
    On 2012-06-04 15:07, Thomas Gleixner wrote:
    > On Mon, 4 Jun 2012, Jan Kiszka wrote:
    >> On 2012-06-04 13:21, Thomas Gleixner wrote:
    >> So this shortcut requires some checks before being applied to a specific
    >> MSI/MSI-X vector.
    >>
    >>
    >> Taking KVM aside, my general question remains if threaded MSI handlers
    >> of all devices really need to apply IRQF_ONESHOT though they should have
    >> no use for it.
    >
    > In theory no, but we had more than one incident, where threaded irqs
    > w/o a primary handler and w/o IRQF_ONEHSOT lead to full system
    > starvation. Linus requested this sanity check and I think it's sane
    > and required.

    OK.

    >
    > In fact it's a non issue for MSI. MSI uses handle_edge_irq which does
    > not mask the interrupt. IRQF_ONESHOT is a noop for that flow handler.

    Isn't irq_finalize_oneshot processes for all flows?

    Jan

    --
    Siemens AG, Corporate Technology, CT T DE IT 1
    Corporate Competence Center Embedded Linux


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