Re: [PATCH v3 1/3] Introduce a workqueue to deliver PIT timer interrupts.
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On 2010-06-16 23:11, Chris Lalancette wrote: > We really want to "kvm_set_irq" during the hrtimer callback, > but that is risky because that is during interrupt context. > Instead, offload the work to a workqueue, which is a bit safer > and should provide most of the same functionality. Unfortunately, workqueues do not have fixed kthread associations (and "kvm-pit-wq" would be too unspecific when running multiple VMs). So I just realized that this subtly breaks the ability to run KVM guests with RT priority (boot managers with timeouts hang as the workqueue starves). Before throwing some kthread_worker at this, could someone help me recalling what was "risky" here? That the PIT IRQ may have to be broadcast to a large number of VCPUs? I would offer to include this information in my changelog. ;) Thanks, Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- 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