[Xen-devel] Re: [PATCH 2/3] mm: Add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro

[Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>]

On Mon, 2011-03-28 at 11:24 +0200, Daniel Kiper wrote:
> Add SECTION_ALIGN_UP() and SECTION_ALIGN_DOWN() macro which aligns
> given pfn to upper section and lower section boundary accordingly.
> 
> Signed-off-by: Daniel Kiper <dkiper@xxxxxxxxxxxx>
> ---
>  include/linux/mmzone.h |    3 +++
>  1 files changed, 3 insertions(+), 0 deletions(-)
> 
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 02ecb01..d342820 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -931,6 +931,9 @@ static inline unsigned long early_pfn_to_nid(unsigned 
> long pfn)
>  #define pfn_to_section_nr(pfn) ((pfn) >> PFN_SECTION_SHIFT)
>  #define section_nr_to_pfn(sec) ((sec) << PFN_SECTION_SHIFT)
> 
> +#define SECTION_ALIGN_UP(pfn)        (((pfn) + PAGES_PER_SECTION - 1) & 
> PAGE_SECTION_MASK)
> +#define SECTION_ALIGN_DOWN(pfn)      ((pfn) & PAGE_SECTION_MASK)

There are certainly a lot of different ways to do this, including using
the existing ALIGN() macro, but you won't be the first to open-code
it. :)

Acked-by: Dave Hansen <dave@xxxxxxxxxxxxxxxxxx>

-- Dave


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