Re: [PATCH v6 2/3] KVM: dynamic halt_poll_ns adjustment

From: Paolo Bonzini
Date: Thu Sep 03 2015 - 03:31:50 EST




On 02/09/2015 21:23, David Matlack wrote:
>
> I actually wasn't thinking about vcpu->halt_poll_ns though. If
> single_task_running() breaks us out of the loop we will "goto out" instead
> of scheduling. My suspicion is this will cause us to loop calling
> kvm_vcpu_block and starve the waiting task (at least until need_resched()),
> which would break the "only hog the cpu when idle" aspect of halt-polling.

That's definitely a bug, yes.

Paolo
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