From: Nick Piggin <npiggin@suse.de>
To: Jan Beulich <jbeulich@novell.com>
Cc: mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] x86: make mm/gup.c more virtualization friendly
Date: Tue, 23 Sep 2008 06:42:57 +0200 [thread overview]
Message-ID: <20080923044257.GC11907@wotan.suse.de> (raw)
In-Reply-To: <48D142E1.76E4.0078.0@novell.com>
No objections from me.
On Wed, Sep 17, 2008 at 04:48:17PM +0100, Jan Beulich wrote:
> Since pte_flags() is much cheaper than pte_val() in some virtualized
> environments (namely, Xen), use the former whereever possible.
>
> Signed-off-by: Jan Beulich <jbeulich@novell.com>
> Cc: Nick Piggin <npiggin@suse.de>
>
> ---
> arch/x86/mm/gup.c | 10 +++++-----
> include/asm-x86/pgtable.h | 2 +-
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
> --- linux-2.6.27-rc6/arch/x86/mm/gup.c 2008-08-21 14:37:29.000000000 +0200
> +++ 2.6.27-rc6-x86-gup-virt/arch/x86/mm/gup.c 2008-09-02 13:33:42.000000000 +0200
> @@ -82,7 +82,7 @@ static noinline int gup_pte_range(pmd_t
> pte_t pte = gup_get_pte(ptep);
> struct page *page;
>
> - if ((pte_val(pte) & (mask | _PAGE_SPECIAL)) != mask) {
> + if ((pte_flags(pte) & (mask | _PAGE_SPECIAL)) != mask) {
> pte_unmap(ptep);
> return 0;
> }
> @@ -116,10 +116,10 @@ static noinline int gup_huge_pmd(pmd_t p
> mask = _PAGE_PRESENT|_PAGE_USER;
> if (write)
> mask |= _PAGE_RW;
> - if ((pte_val(pte) & mask) != mask)
> + if ((pte_flags(pte) & mask) != mask)
> return 0;
> /* hugepages are never "special" */
> - VM_BUG_ON(pte_val(pte) & _PAGE_SPECIAL);
> + VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
> VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
>
> refs = 0;
> @@ -173,10 +173,10 @@ static noinline int gup_huge_pud(pud_t p
> mask = _PAGE_PRESENT|_PAGE_USER;
> if (write)
> mask |= _PAGE_RW;
> - if ((pte_val(pte) & mask) != mask)
> + if ((pte_flags(pte) & mask) != mask)
> return 0;
> /* hugepages are never "special" */
> - VM_BUG_ON(pte_val(pte) & _PAGE_SPECIAL);
> + VM_BUG_ON(pte_flags(pte) & _PAGE_SPECIAL);
> VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
>
> refs = 0;
> --- linux-2.6.27-rc6/include/asm-x86/pgtable.h 2008-08-21 14:37:34.000000000 +0200
> +++ 2.6.27-rc6-x86-gup-virt/include/asm-x86/pgtable.h 2008-09-02 13:31:50.000000000 +0200
> @@ -183,7 +183,7 @@ static inline int pte_exec(pte_t pte)
>
> static inline int pte_special(pte_t pte)
> {
> - return pte_val(pte) & _PAGE_SPECIAL;
> + return pte_flags(pte) & _PAGE_SPECIAL;
> }
>
> static inline int pmd_large(pmd_t pte)
>
>
prev parent reply other threads:[~2008-09-23 4:43 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-09-17 15:48 [PATCH] x86: make mm/gup.c more virtualization friendly Jan Beulich
2008-09-18 10:15 ` Ingo Molnar
2008-09-23 4:42 ` Nick Piggin [this message]
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