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Date: Tue, 15 Mar 2016 16:47:31 +0100
From: Borislav Petkov <bp@alien8.de>
To: Toshi Kani <toshi.kani@hpe.com>
Cc: "Luis R. Rodriguez" <mcgrof@kernel.org>,
        "mingo@kernel.org" <mingo@kernel.org>, "hpa@zytor.com" <hpa@zytor.com>,
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Subject: Re: [PATCH 1/2] x86/mm/pat: Change pat_disable() to emulate PAT table
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On Tue, Mar 15, 2016 at 09:43:15AM -0600, Toshi Kani wrote:
> > Please use on init paths boot_cpu_has(X86_FEATURE_PAT) and on fast paths
> > static_cpu_has(X86_FEATURE_PAT). No more of that cpu_has_XXX ugliness.
> 
> 'cpu_has_pat' is defined as 'boot_cpu_has(X86_FEATURE_PAT)'.  Do you mean
> it should explicitly use 'boot_cpu_has(X86_FEATURE_PAT)'?

No, read what I said.

We use boot_cpu_has(<feature_bit>) on slow paths (i.e., init, bootup,
etc), where speed is not that important. static_cpu_has(<feature_bit>)
is an optimized version which should be used in hot paths.

-- 
Regards/Gruss,
    Boris.

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