On Mon, 4 Jun 2012, Jan Kiszka wrote: > 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? Right, forgot about that. The only way we can avoid that, is that we get a hint from the underlying irq chip/ handler setup with an extra flag to tell the core, that it's safe to avoid the ONESHOT/finalize magic. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
