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From: Nikunj A Dadhania <nikunj@linux.vnet.ibm.com>
To: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>,
        Avi Kivity <avi@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Marcelo Tosatti <mtosatti@redhat.com>,
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        Carsten Otte <cotte@de.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        KVM <kvm@vger.kernel.org>, chegu vinod <chegu_vinod@hp.com>,
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        Gleb Natapov <gleb@redhat.com>, linux390@de.ibm.com,
        Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
        Joerg Roedel <joerg.roedel@amd.com>
Subject: Re: [PATCH RFC 1/2] kvm vcpu: Note down pause loop exit
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Date: Thu, 12 Jul 2012 16:28:59 +0530
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On Wed, 11 Jul 2012 16:22:29 +0530, Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> wrote:
> On 07/11/2012 02:23 PM, Avi Kivity wrote:
> >
> > This adds some tiny overhead to vcpu entry.  You could remove it by
> > using the vcpu->requests mechanism to clear the flag, since
> > vcpu->requests is already checked on every entry.
> 
> So IIUC,  let's have request bit for indicating PLE,
> 
> pause_interception() /handle_pause()
> {
>   make_request(PLE_REQUEST)
>   vcpu_on_spin()
> 
> }
> 
> check_eligibility()
>   {
>   !test_request(PLE_REQUEST) || ( test_request(PLE_REQUEST)  && 
> dy_eligible())
> .
> .
> }
> 
> vcpu_run()
> {
> 
> check_request(PLE_REQUEST)
>
I know check_request will clear PLE_REQUEST, but you just need a
clear_request here, right?