Re: [PATCH v13 6/8] arm: add pmd_[dirty|mkclean] for THP

From: Will Deacon
Date: Fri Jul 18 2014 - 04:48:57 EST


On Fri, Jul 18, 2014 at 07:53:04AM +0100, Minchan Kim wrote:
> MADV_FREE needs pmd_dirty and pmd_mkclean for detecting recent
> overwrite of the contents since MADV_FREE syscall is called for
> THP page.
>
> This patch adds pmd_dirty and pmd_mkclean for THP page MADV_FREE
> support.
>
> Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
> Cc: Will Deacon <will.deacon@xxxxxxx>
> Cc: Steve Capper <steve.capper@xxxxxxxxxx>
> Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
> Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
> ---
> arch/arm/include/asm/pgtable-3level.h | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/arch/arm/include/asm/pgtable-3level.h b/arch/arm/include/asm/pgtable-3level.h
> index 85c60adc8b60..830f84f2d277 100644
> --- a/arch/arm/include/asm/pgtable-3level.h
> +++ b/arch/arm/include/asm/pgtable-3level.h
> @@ -220,6 +220,8 @@ static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
> #define pmd_trans_splitting(pmd) (pmd_val(pmd) & PMD_SECT_SPLITTING)
> #endif
>
> +#define pmd_dirty(pmd) (pmd_val(pmd) & PMD_SECT_DIRTY)
> +
> #define PMD_BIT_FUNC(fn,op) \
> static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }
>
> @@ -228,6 +230,7 @@ PMD_BIT_FUNC(mkold, &= ~PMD_SECT_AF);
> PMD_BIT_FUNC(mksplitting, |= PMD_SECT_SPLITTING);
> PMD_BIT_FUNC(mkwrite, &= ~PMD_SECT_RDONLY);
> PMD_BIT_FUNC(mkdirty, |= PMD_SECT_DIRTY);
> +PMD_BIT_FUNC(mkclean, &= ~PMD_SECT_DIRTY);
> PMD_BIT_FUNC(mkyoung, |= PMD_SECT_AF);
>
> #define pmd_mkhuge(pmd) (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))

Looks fine to me, but again, it would be great if Steve can take a look too.

Will
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