linux-kernel - Re: [PATCH 6/6] KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva

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Message-ID: <4FEC9A2B.6000104@redhat.com>
Date:	Thu, 28 Jun 2012 20:53:47 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Takuya Yoshikawa <yoshikawa.takuya@....ntt.co.jp>
CC:	mtosatti@...hat.com, agraf@...e.de, paulus@...ba.org,
	aarcange@...hat.com, kvm@...r.kernel.org, kvm-ppc@...r.kernel.org,
	linux-kernel@...r.kernel.org, takuya.yoshikawa@...il.com
Subject: Re: [PATCH 6/6] KVM: MMU: Avoid handling same rmap_pde in kvm_handle_hva_range()

On 06/28/2012 05:02 AM, Takuya Yoshikawa wrote:
> When we invalidate a THP page, we call the handler with the same
> rmap_pde argument 512 times in the following loop:
> 
>   for each guest page in the range
>     for each level
>       unmap using rmap
> 
> This patch avoids these extra handler calls by changing the loop order
> like this:
> 
>   for each level
>     for each rmap in the range
>       unmap using rmap
> 
> With the preceding patches in the patch series, this made THP page
> invalidation more than 5 times faster on our x86 host: the host became
> more responsive during swapping the guest's memory as a result.
> 
> Note: in the new code we could not use trace_kvm_age_page(), so we just
> dropped the point from kvm_handle_hva_range().
> 

Can't it be pushed to handler()?



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


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