linux-kernel - Re: [PATCH v6 2/3] KVM: dynamic halt_poll

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Date:	Thu, 3 Sep 2015 16:52:01 +0800
From:	Wanpeng Li <wanpeng.li@...mail.com>
To:	Paolo Bonzini <pbonzini@...hat.com>,
	David Matlack <dmatlack@...gle.com>
CC:	kvm list <kvm@...r.kernel.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v6 2/3] KVM: dynamic halt_poll_ns adjustment

On 9/3/15 3:31 PM, Paolo Bonzini wrote:
>
> 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.

Ok, I will send out v7 to fix this in this sunday since there is 
vacation in my country currently.

Regards,
Wanpeng Li

>
> Paolo

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