Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay

From	Wanpeng Li <kernellwp@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay
Date	2017-07-03 10:50 +0200
Message-ID	<tZ5do-74o-29@gated-at.bofh.it> (permalink)
References	(2 earlier) <tYC1I-2Ms-5@gated-at.bofh.it> <tYCl3-2SW-9@gated-at.bofh.it> <tZ47E-6mA-17@gated-at.bofh.it> <tZ4AH-6PE-33@gated-at.bofh.it> <tZ4Km-6Tf-9@gated-at.bofh.it>
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2017-07-03 16:16 GMT+08:00 Paolo Bonzini <pbonzini@redhat.com>:
>
>
> On 03/07/2017 10:08, Wanpeng Li wrote:
>>> Yeah, I'm not entirely satisfied with it but it's working: start_sw
>>> timer will see ktimer->pending and do nothing.
>>>
>>> But thinking more about it, maybe the "if (r)" can be omitted
>>> completely?  We need to benchmark it but it can be done.
>> "if (r)" makes codes more understandable, in addition, calling expired
>> the pending timer here looks weird though ktimer->pending.
>
> We can remove the call to apic_timer_expired too (sorry if I was too
> terse). :)  start_sw_period and start_sw_tscdeadline would take care of it.

IRQ disable and ktime_get() in start_sw_tscdeadline() are more
expensive. So maybe current status is a better choice. :)

Regards,
Wanpeng Li

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[PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-06-29 19:00 +0200
  Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-07-02 03:40 +0200
    Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-07-02 04:00 +0200
      Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-07-03 09:40 +0200
        Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-07-03 10:10 +0200
          Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Paolo Bonzini <pbonzini@redhat.com> - 2017-07-03 10:20 +0200
            Re: [PATCH 3/3] KVM: LAPIC: Fix lapic timer injection delay Wanpeng Li <kernellwp@gmail.com> - 2017-07-03 10:50 +0200

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