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From: Paolo Bonzini <pbonzini@redhat.com>
To: David Matlack <dmatlack@google.com>
Cc: Wanpeng Li <wanpeng.li@hotmail.com>,
	kvm list <kvm@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v6 2/3] KVM: dynamic halt_poll_ns adjustment
Date: Thu, 3 Sep 2015 09:31:39 +0200	[thread overview]
Message-ID: <55E7F75B.2030502@redhat.com> (raw)
In-Reply-To: <CALzav=fedir209XorasYpXxC1Ljp+B63KgRcuoWf4nPEXTdj=Q@mail.gmail.com>



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

  reply	other threads:[~2015-09-03  7:31 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <1441178971-3836-1-git-send-email-wanpeng.li@hotmail.com>
2015-09-02  7:29 ` [PATCH v6 1/3] KVM: make halt_poll_ns per-vCPU Wanpeng Li
2015-09-02  7:29 ` [PATCH v6 2/3] KVM: dynamic halt_poll_ns adjustment Wanpeng Li
2015-09-02 18:09   ` David Matlack
2015-09-02 19:12     ` Paolo Bonzini
2015-09-02 19:23       ` David Matlack
2015-09-03  7:31         ` Paolo Bonzini [this message]
2015-09-03  8:52           ` Wanpeng Li
2015-09-03  9:23     ` Wanpeng Li
2015-09-03 16:07       ` David Matlack
2015-09-04  0:15         ` Wanpeng Li
2015-09-04  1:16     ` Wanpeng Li
2015-09-04  1:42       ` Wanpeng Li

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