Re: [PATCH v4 2/9] KVM: Switch IRQ subsystem to SRCU

Jan Kiszka
2010-11-09T11:22:05Z

Am 09.11.2010 11:49, Avi Kivity wrote:
> On 11/08/2010 01:21 PM, Jan Kiszka wrote:
>> Ack and mask notifiers typically call back into kvm_set_irq, thus may
>> iterate over all VCPUs of a VM. Better keep this path preemptible to
>> prevent that user-space can massivle influence scheduling latencies. Use
>> sleepable RCU for the protection of irq_routing and the notfier lists.
>>
>
> What about preemptible RCU, now in mainline?

Granted, that would resolve the preemption issue but not allow to use
sleepy locks inside this section (as done by the last patch in this series).

Jan

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