Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v2 1/3] context_tracking: Split guest_enter/exit_irqoff
To:     Wanpeng Li <kernellwp@gmail.com>
Cc:     LKML <linux-kernel@vger.kernel.org>, kvm <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Sean Christopherson <seanjc@google.com>,
        Vitaly Kuznetsov <vkuznets@redhat.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Joerg Roedel <joro@8bytes.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Michael Tokarev <mjt@tls.msk.ru>
References: <1618298169-3831-1-git-send-email-wanpengli@tencent.com>
 <1618298169-3831-2-git-send-email-wanpengli@tencent.com>
 <81112cec-72fa-dd8c-21c8-b24f51021f43@de.ibm.com>
 <CANRm+CwNxcKPKdV4Bxr-5sWJtg_SKZEN5atGJKRyLcVnWVSKSg@mail.gmail.com>
From:   Christian Borntraeger <borntraeger@de.ibm.com>
Message-ID: <4551632e-5584-29f6-68dd-d85fa968858b@de.ibm.com>
Date:   Tue, 13 Apr 2021 09:48:32 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.9.0
MIME-Version: 1.0
In-Reply-To: <CANRm+CwNxcKPKdV4Bxr-5sWJtg_SKZEN5atGJKRyLcVnWVSKSg@mail.gmail.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Precedence: bulk


On 13.04.21 09:38, Wanpeng Li wrote:
> On Tue, 13 Apr 2021 at 15:35, Christian Borntraeger
> <borntraeger@de.ibm.com> wrote:
>>
>>
>>
>> On 13.04.21 09:16, Wanpeng Li wrote:
>> [...]
>>
>>> @@ -145,6 +155,13 @@ static __always_inline void guest_exit_irqoff(void)
>>>    }
>>>
>>>    #else
THis is the else part


>>> +static __always_inline void context_guest_enter_irqoff(void)
>>> +{
>>> +     instrumentation_begin();

2nd on
>>> +     rcu_virt_note_context_switch(smp_processor_id());
>>> +     instrumentation_end();
2nd off
>>> +}
>>> +
>>>    static __always_inline void guest_enter_irqoff(void)
>>>    {
>>>        /*
>>> @@ -155,10 +172,13 @@ static __always_inline void guest_enter_irqoff(void)
>>>        instrumentation_begin();

first on
>>>        vtime_account_kernel(current);
>>>        current->flags |= PF_VCPU;
>>> -     rcu_virt_note_context_switch(smp_processor_id());
>>>        instrumentation_end();

first off
>>> +
>>> +     context_guest_enter_irqoff();
here we call the 2nd on and off.
>>
>> So we now do instrumentation_begin 2 times?
> 
> Similar to context_guest_enter_irqoff() ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN.

For the
ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN part
context_guest_enter_irqoff()
does not have instrumentation_begin/end.

Or did I miss anything.