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Date: Mon, 3 Nov 2008 15:09:00 -0500
From: Josh Boyer <jwboyer@linux.vnet.ibm.com>
To: Hollis Blanchard <hollisb@us.ibm.com>
Subject: Re: [PATCH] powerpc/44x: declare tlb_44x_index for use in C code
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On Fri, 31 Oct 2008 14:03:12 -0500
Hollis Blanchard <hollisb@us.ibm.com> wrote:

> # HG changeset patch
> # User Hollis Blanchard <hollisb@us.ibm.com>
> # Date 1225479768 18000
> # Node ID 59bd162a744af080479fedffa97d01e26dceee6a
> # Parent  635f3f74befc230d93f79dc3198c509394247ee8
> powerpc/44x: declare tlb_44x_index for use in C code
> 
> KVM currently ignores the host's round robin TLB eviction selection, instead
> maintaining its own TLB state and its own round robin index. However, by
> participating in the normal 44x TLB selection, we can drop the alternate TLB
> processing in KVM. This results in a significant performance improvement,
> since that processing currently must be done on *every* guest exit.
> 
> Accordingly, KVM needs to be able to access and increment tlb_44x_index.
> (KVM on 440 cannot be a module, so there is no need to export this symbol.)
> 
> Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>

Acked-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>

> 
> ---
> 
> Josh, can I get your ack? I'll submit through the KVM tree as usual.
> 
> diff --git a/arch/powerpc/include/asm/mmu-44x.h b/arch/powerpc/include/asm/mmu-44x.h
> --- a/arch/powerpc/include/asm/mmu-44x.h
> +++ b/arch/powerpc/include/asm/mmu-44x.h
> @@ -54,6 +54,7 @@
>  #ifndef __ASSEMBLY__
> 
>  extern unsigned int tlb_44x_hwater;
> +extern unsigned int tlb_44x_index;
> 
>  typedef struct {
>  	unsigned long id;