Re: [PATCH v2 1/2] thp: add HPAGE_PMD_* definitions for !CONFIG_TRANSPARENT_HUGEPAGE

[Hillf Danton <dhillf@gmail.com>]

On Fri, Mar 2, 2012 at 8:31 AM, Naoya Horiguchi
<n-horiguchi@ah.jp.nec.com> wrote:
> These macros will be used in later patch, where all usage are expected
> to be optimized away without #ifdef CONFIG_TRANSPARENT_HUGEPAGE.
> But to detect unexpected usages, we convert existing BUG() to BUILD_BUG().
>
> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>

Acked-by: Hillf Danton <dhillf@gmail.com>

> ---
>  include/linux/huge_mm.h |   11 ++++++-----
>  1 files changed, 6 insertions(+), 5 deletions(-)
>
> diff --git linux-next-20120228.orig/include/linux/huge_mm.h linux-next-20120228/include/linux/huge_mm.h
> index f56cacb..c8af7a2 100644
> --- linux-next-20120228.orig/include/linux/huge_mm.h
> +++ linux-next-20120228/include/linux/huge_mm.h
> @@ -51,6 +51,9 @@ extern pmd_t *page_check_address_pmd(struct page *page,
>                                     unsigned long address,
>                                     enum page_check_address_pmd_flag flag);
>
> +#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
> +#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
> +
>  #ifdef CONFIG_TRANSPARENT_HUGEPAGE
>  #define HPAGE_PMD_SHIFT HPAGE_SHIFT
>  #define HPAGE_PMD_MASK HPAGE_MASK
> @@ -102,8 +105,6 @@ extern void __split_huge_page_pmd(struct mm_struct *mm, pmd_t *pmd);
>                BUG_ON(pmd_trans_splitting(*____pmd) ||                 \
>                       pmd_trans_huge(*____pmd));                       \
>        } while (0)
> -#define HPAGE_PMD_ORDER (HPAGE_PMD_SHIFT-PAGE_SHIFT)
> -#define HPAGE_PMD_NR (1<<HPAGE_PMD_ORDER)
>  #if HPAGE_PMD_ORDER > MAX_ORDER
>  #error "hugepages can't be allocated by the buddy allocator"
>  #endif
> @@ -158,9 +159,9 @@ static inline struct page *compound_trans_head(struct page *page)
>        return page;
>  }
>  #else /* CONFIG_TRANSPARENT_HUGEPAGE */
> -#define HPAGE_PMD_SHIFT ({ BUG(); 0; })
> -#define HPAGE_PMD_MASK ({ BUG(); 0; })
> -#define HPAGE_PMD_SIZE ({ BUG(); 0; })
> +#define HPAGE_PMD_SHIFT ({ BUILD_BUG(); 0; })
> +#define HPAGE_PMD_MASK ({ BUILD_BUG(); 0; })
> +#define HPAGE_PMD_SIZE ({ BUILD_BUG(); 0; })
>
>  #define hpage_nr_pages(x) 1
>
> --
> 1.7.7.6
>

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