linux-kernel - Re: [patches] [PATCH] [13/50] x86: Fix and reenable CLFLUSH support inchange_page

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Message-Id: <46F79021.76E4.0078.0@novell.com>
Date:	Mon, 24 Sep 2007 09:23:29 +0100
From:	"Jan Beulich" <jbeulich@...ell.com>
To:	"Andi Kleen" <ak@...e.de>
Cc:	<linux-kernel@...r.kernel.org>, <patches@...-64.org>
Subject: Re: [patches] [PATCH] [13/50] x86: Fix and reenable CLFLUSH
	support inchange_page_attr()

>@@ -162,7 +198,7 @@ __change_page_attr(unsigned long address
> 	/* on x86-64 the direct mapping set at boot is not using 4k pages */
>  	BUG_ON(PageReserved(kpte_page));
> 
>-	save_page(kpte_page);
>+	save_page(kpte_page, 0);
> 	if (page_private(kpte_page) == 0)
> 		revert_page(address, ref_prot);
> 	return 0;

What is the point of continuing to launder kpte_page here? Page table pages
never get their caching attributes changed, nor would their direct mapping
ever change. (Same for i386, obviously.)

Jan

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