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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Sean Christopherson <seanjc@google.com>,
	Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Michael Tokarev <mjt@tls.msk.ru>
Subject: Re: [PATCH v3 2/9] context_tracking: Move guest exit vtime accounting to separate helpers
Date: Tue, 20 Apr 2021 20:48:22 +0200
Message-ID: <cca590ee-ade6-dd17-aed8-c927a4f02ec0@de.ibm.com> (raw)
In-Reply-To: <20210415222106.1643837-3-seanjc@google.com>



On 16.04.21 00:20, Sean Christopherson wrote:
> From: Wanpeng Li <wanpengli@tencent.com>
> 
> Provide separate vtime accounting functions for guest exit instead of
> open coding the logic within the context tracking code.  This will allow
> KVM x86 to handle vtime accounting slightly differently when using
> tick-based accounting.
> 
> Suggested-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Michael Tokarev <mjt@tls.msk.ru>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

Reviewed-by: Christian Borntraeger <borntraeger@de.ibm.com>

> ---
>   include/linux/context_tracking.h | 24 +++++++++++++++++-------
>   1 file changed, 17 insertions(+), 7 deletions(-)
> 
> diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
> index 200d30cb3a82..7cf03a8e5708 100644
> --- a/include/linux/context_tracking.h
> +++ b/include/linux/context_tracking.h
> @@ -137,15 +137,20 @@ static __always_inline void context_tracking_guest_exit_irqoff(void)
>   		__context_tracking_exit(CONTEXT_GUEST);
>   }
>   
> -static __always_inline void guest_exit_irqoff(void)
> +static __always_inline void vtime_account_guest_exit(void)
>   {
> -	context_tracking_guest_exit_irqoff();
> -
> -	instrumentation_begin();
>   	if (vtime_accounting_enabled_this_cpu())
>   		vtime_guest_exit(current);
>   	else
>   		current->flags &= ~PF_VCPU;
> +}
> +
> +static __always_inline void guest_exit_irqoff(void)
> +{
> +	context_tracking_guest_exit_irqoff();
> +
> +	instrumentation_begin();
> +	vtime_account_guest_exit();
>   	instrumentation_end();
>   }
>   
> @@ -166,12 +171,17 @@ static __always_inline void guest_enter_irqoff(void)
>   
>   static __always_inline void context_tracking_guest_exit_irqoff(void) { }
>   
> -static __always_inline void guest_exit_irqoff(void)
> +static __always_inline void vtime_account_guest_exit(void)
>   {
> -	instrumentation_begin();
> -	/* Flush the guest cputime we spent on the guest */
>   	vtime_account_kernel(current);
>   	current->flags &= ~PF_VCPU;
> +}
> +
> +static __always_inline void guest_exit_irqoff(void)
> +{
> +	instrumentation_begin();
> +	/* Flush the guest cputime we spent on the guest */
> +	vtime_account_guest_exit();
>   	instrumentation_end();
>   }
>   #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
> 

  reply index

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-15 22:20 [PATCH v3 0/9] KVM: Fix tick-based accounting for x86 guests Sean Christopherson
2021-04-15 22:20 ` [PATCH v3 1/9] context_tracking: Move guest exit context tracking to separate helpers Sean Christopherson
2021-04-20 18:48   ` Christian Borntraeger
2021-04-21 10:57   ` Frederic Weisbecker
2021-04-15 22:20 ` [PATCH v3 2/9] context_tracking: Move guest exit vtime accounting " Sean Christopherson
2021-04-20 18:48   ` Christian Borntraeger [this message]
2021-04-15 22:21 ` [PATCH v3 3/9] KVM: x86: Defer tick-based accounting 'til after IRQ handling Sean Christopherson
2021-04-20 23:14   ` Frederic Weisbecker
2021-04-20 23:26     ` Sean Christopherson
2021-04-21 10:11       ` Frederic Weisbecker
2021-04-21 12:19       ` Frederic Weisbecker
2021-04-28 22:38         ` Sean Christopherson
2021-04-21 10:07   ` Frederic Weisbecker
2021-04-15 22:21 ` [PATCH v3 4/9] sched/vtime: Move vtime accounting external declarations above inlines Sean Christopherson
2021-04-21  7:02   ` Christian Borntraeger
2021-04-15 22:21 ` [PATCH v3 5/9] sched/vtime: Move guest enter/exit vtime accounting to vtime.h Sean Christopherson
2021-04-15 22:21 ` [PATCH v3 6/9] context_tracking: Consolidate guest enter/exit wrappers Sean Christopherson
2021-04-15 22:21 ` [PATCH v3 7/9] context_tracking: KVM: Move guest enter/exit wrappers to KVM's domain Sean Christopherson
2021-04-21  7:10   ` Christian Borntraeger
2021-04-15 22:21 ` [PATCH v3 8/9] KVM: x86: Consolidate guest enter/exit logic to common helpers Sean Christopherson
2021-04-15 22:21 ` [PATCH v3 9/9] KVM: Move instrumentation-safe annotations for enter/exit to x86 code Sean Christopherson
2021-04-21  8:09   ` Christian Borntraeger
2021-04-22 14:38     ` Sven Schnelle
2021-04-23  9:32       ` Vasily Gorbik
2021-04-20 23:33 ` [PATCH v3 0/9] KVM: Fix tick-based accounting for x86 guests Frederic Weisbecker

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