From mboxrd@z Thu Jan  1 00:00:00 1970
From: Avi Kivity <avi@redhat.com>
Subject: Re: [PATCH 4/4] KVM MMU: do not intercept invlpg if 'oos_shadow'
 is disabled
Date: Fri, 30 Apr 2010 12:56:26 +0300
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Cc: Marcelo Tosatti <mtosatti@redhat.com>,
	KVM list <kvm@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
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On 04/30/2010 12:05 PM, Xiao Guangrong wrote:
> If 'oos_shadow' == 0, intercepting invlpg command is really
> unnecessary.
>
> And it's good for us to compare the performance between enable 'oos_shadow'
> and disable 'oos_shadow'
>
> @@ -74,8 +74,9 @@ static int dbg = 0;
>   module_param(dbg, bool, 0644);
>   #endif
>
> -static int oos_shadow = 1;
> +int __read_mostly oos_shadow = 1;
>   module_param(oos_shadow, bool, 0644);
> +EXPORT_SYMBOL_GPL(oos_shadow);
>    

Please rename to kvm_oos_shadow to reduce potential for conflict with 
other global names.

But really, this is a debug option, I don't expect people to run with 
oos_shadow=0, so there's not much motivation to optimize it.

-- 
Do not meddle in the internals of kernels, for they are subtle and quick to panic.