DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com 893AAC058EBF
Subject: Re: [PATCH v2 1/4] KVM: add spinlock optimization framework
To: "Longpeng(Mike)" <longpeng2@huawei.com>, pbonzini@redhat.com,
        rkrcmar@redhat.com
Cc: agraf@suse.com, borntraeger@de.ibm.com, cohuck@redhat.com,
        christoffer.dall@linaro.org, marc.zyngier@arm.com,
        james.hogan@imgtec.com, kvm@vger.kernel.org,
        linux-kernel@vger.kernel.org, weidong.huang@huawei.com,
        arei.gonglei@huawei.com, wangxinxin.wang@huawei.com,
        longpeng.mike@gmail.com
References: <1502165135-4784-1-git-send-email-longpeng2@huawei.com>
 <1502165135-4784-2-git-send-email-longpeng2@huawei.com>
From: David Hildenbrand <david@redhat.com>
Organization: Red Hat GmbH
Message-ID: <8f4e336d-82b2-9148-eac3-ad411e6a16ef@redhat.com>
Date: Tue, 8 Aug 2017 10:42:20 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101
 Thunderbird/52.2.1
MIME-Version: 1.0
In-Reply-To: <1502165135-4784-2-git-send-email-longpeng2@huawei.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1373
Lines: 57


> +bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
> +{
> +	return false;
> +}

why don't we need an EXPORT_SYMBOL here?

> +
>  /* Just ensure a guest exit from a particular CPU */
>  static void exit_vm_noop(void *info)
>  {
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 15252d7..e7720d2 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2317,7 +2317,7 @@ static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
>  #endif
>  }
>  
> -void kvm_vcpu_on_spin(struct kvm_vcpu *me)
> +void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool me_in_kern)
>  {
>  	struct kvm *kvm = me->kvm;
>  	struct kvm_vcpu *vcpu;
> @@ -2348,6 +2348,8 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me)
>  				continue;
>  			if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
>  				continue;
> +			if (me_in_kern && !kvm_arch_vcpu_in_kernel(vcpu))
> +				continue;


hm, does this patch compile? (me_in_kern)

I would even move this to an other patch.

Maybe even split into

a) introducing kvm_arch_vcpu_in_kernel() for all archs
b) modifying kvm_vcpu_on_spin(), passing the result from
kvm_arch_vcpu_in_kernel()
c) filling kvm_arch_vcpu_in_kernel() with life for different archs
(multiple patches)
d) pimping kvm_vcpu_on_spin()

>  			if (!kvm_vcpu_eligible_for_directed_yield(vcpu))
>  				continue;
>  
> 


-- 

Thanks,

David