Re: [PATCH 2/7] Add various hugetlb page table fix

[Catalin Marinas <catalin.marinas@xxxxxxx>]

On 30 January 2012 07:57,  <bill4carson@xxxxxxxxx> wrote:
> diff --git a/arch/arm/include/asm/pgtable-2level.h b/arch/arm/include/asm/pgtable-2level.h
> index 2317a71..062c93c 100644
> --- a/arch/arm/include/asm/pgtable-2level.h
> +++ b/arch/arm/include/asm/pgtable-2level.h
> @@ -123,6 +123,11 @@
>  #define L_PTE_USER             (_AT(pteval_t, 1) << 8)
>  #define L_PTE_XN               (_AT(pteval_t, 1) << 9)
>  #define L_PTE_SHARED           (_AT(pteval_t, 1) << 10)        /* shared(v6), coherent(xsc3) */
> +#ifdef CONFIG_ARM_HUGETLB_SUPPORT
> +#define L_PTE_HUGEPAGE (_AT(pteval_t, 1) << 11) /* mark hugepage */

Do we actually need this bit? The checks are done starting from the
top pgd/pud/pmd. So we stop at the pmd level and check whether it is
table or a section mapping. I don't think we ever check a pte entry
for whether it is huge or not (as, at least with the implementation
you posted, it does not support 64K pages).

> +#define L_PTE_HPAGE_2M  (_AT(pteval_t, 1) << 12) /* only when HUGEPAGE set */
> +#define L_PTE_HPAGE_16M (_AT(pteval_t, 1) << 13) /* only when HUGEPAGE set */

If we go for 2MB only, we can ignore both definitions here.

-- 
Catalin

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