linux-kernel - Re: [PATCH v2] KVM: MMU: optimize pte write path if don't have protected sp

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Message-ID: <4DCA72C3.6050300@redhat.com>
Date:	Wed, 11 May 2011 14:28:03 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Xiao Guangrong <xiaoguangrong@...fujitsu.com>
CC:	Marcelo Tosatti <mtosatti@...hat.com>,
	LKML <linux-kernel@...r.kernel.org>, KVM <kvm@...r.kernel.org>
Subject: Re: [PATCH v2] KVM: MMU: optimize pte write path if don't have protected
 sp

On 05/11/2011 05:44 AM, Xiao Guangrong wrote:
> Simply return from kvm_mmu_pte_write path if no shadow page is
> write-protected, then we can avoid to walk all shadow pages and hold
> mmu-lock
>
> @@ -1038,8 +1038,10 @@ static void kvm_mmu_free_page(struct kvm *kvm, struct kvm_mmu_page *sp)
>   	hlist_del(&sp->hash_link);
>   	list_del(&sp->link);
>   	free_page((unsigned long)sp->spt);
> -	if (!sp->role.direct)
> +	if (!sp->role.direct) {
>   		free_page((unsigned long)sp->gfns);
> +		atomic_dec(&kvm->arch.indirect_shadow_pages);
> +	}
>   	kmem_cache_free(mmu_page_header_cache, sp);
>   	kvm_mod_used_mmu_pages(kvm, -1);
>   }
> @@ -1536,6 +1538,7 @@ static struct kvm_mmu_page *kvm_mmu_get_page(struct kvm_vcpu *vcpu,
>   			kvm_sync_pages(vcpu, gfn);
>
>   		account_shadowed(vcpu->kvm, gfn);
> +		atomic_inc(&vcpu->kvm->arch.indirect_shadow_pages);
>   	}

Better in account_shadowed()/unaccount_shadowed(), no?


-- 
error compiling committee.c: too many arguments to function

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