Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx> writes:
> [ text/plain ]
> From: root <root@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
>
> Currently the 'huge_pte_alloc' function has two versions, one for the
> BOOK3S and the other one for the BOOK3E platforms. This change splits
> the BOOK3S version into two parts, one for the 4K page size based
> implementation and the other one for the 64K page sized implementation.
> This change is one of the prerequisites towards enabling GENERAL_HUGETLB
> implementation for BOOK3S 64K based huge pages.
I really wish we reduce #ifdefs in C code and start splitting hash
and nonhash code out where ever we can.
What we really want here is a book3s version and in book3s version use
powerpc specific huge_pte_alloc only if GENERAL_HUGETLB was not defined.
Don't limit it to 64k linux page size. We should select between powerpc
specific implementation and generic code using GENERAL_HUGETLB define.
>
> Signed-off-by: Anshuman Khandual <khandual@xxxxxxxxxxxxxxxxxx>
> ---
> arch/powerpc/mm/hugetlbpage.c | 67 +++++++++++++++++++++++++++----------------
> 1 file changed, 43 insertions(+), 24 deletions(-)
>
> diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c
> index 744e24b..a49c6ae 100644
> --- a/arch/powerpc/mm/hugetlbpage.c
> +++ b/arch/powerpc/mm/hugetlbpage.c
> @@ -59,6 +59,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
> return __find_linux_pte_or_hugepte(mm->pgd, addr, NULL, NULL);
> }
>
> +#if !defined(CONFIG_PPC_64K_PAGES) || !defined(CONFIG_PPC_BOOK3S_64)
> static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
> unsigned long address, unsigned pdshift, unsigned pshift)
> {
> @@ -117,6 +118,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
> spin_unlock(&mm->page_table_lock);
> return 0;
> }
> +#endif /* !defined(CONFIG_PPC_64K_PAGES) || !defined(CONFIG_PPC_BOOK3S_64) */
>
> /*
> * These macros define how to determine which level of the page table holds
> @@ -131,6 +133,7 @@ static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
> #endif
>
> #ifdef CONFIG_PPC_BOOK3S_64
> +#ifdef CONFIG_PPC_4K_PAGES
> /*
> * At this point we do the placement change only for BOOK3S 64. This would
> * possibly work on other subarchs.
> @@ -146,32 +149,23 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
>
> addr &= ~(sz-1);
> pg = pgd_offset(mm, addr);
> -
> - if (pshift == PGDIR_SHIFT)
> - /* 16GB huge page */
> - return (pte_t *) pg;
> - else if (pshift > PUD_SHIFT)
> - /*
> - * We need to use hugepd table
> - */
> + if (pshift > PUD_SHIFT) {
> hpdp = (hugepd_t *)pg;
> - else {
> - pdshift = PUD_SHIFT;
> - pu = pud_alloc(mm, pg, addr);
> - if (pshift == PUD_SHIFT)
> - return (pte_t *)pu;
> - else if (pshift > PMD_SHIFT)
> - hpdp = (hugepd_t *)pu;
> - else {
> - pdshift = PMD_SHIFT;
> - pm = pmd_alloc(mm, pu, addr);
> - if (pshift == PMD_SHIFT)
> - /* 16MB hugepage */
> - return (pte_t *)pm;
> - else
> - hpdp = (hugepd_t *)pm;
> - }
> + goto hugepd_search;
> + }
> +
> + pdshift = PUD_SHIFT;
> + pu = pud_alloc(mm, pg, addr);
> + if (pshift > PMD_SHIFT) {
> + hpdp = (hugepd_t *)pu;
> + goto hugepd_search;
> }
> +
> + pdshift = PMD_SHIFT;
> + pm = pmd_alloc(mm, pu, addr);
> + hpdp = (hugepd_t *)pm;
> +
> +hugepd_search:
> if (!hpdp)
> return NULL;
>
> @@ -184,6 +178,31 @@ pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz
> }
>
> #else
> +pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
> +{
> + pgd_t *pg;
> + pud_t *pu;
> + pmd_t *pm;
> + unsigned pshift = __ffs(sz);
> +
> + addr &= ~(sz-1);
> + pg = pgd_offset(mm, addr);
> +
> + if (pshift == PGDIR_SHIFT) /* 16GB Huge Page */
> + return (pte_t *)pg;
> +
> + pu = pud_alloc(mm, pg, addr); /* NA, skipped */
> + if (pshift == PUD_SHIFT)
> + return (pte_t *)pu;
> +
> + pm = pmd_alloc(mm, pu, addr); /* 16MB Huge Page */
> + if (pshift == PMD_SHIFT)
> + return (pte_t *)pm;
> +
> + return NULL;
> +}
> +#endif
> +#else
>
> pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
> {
> --
> 2.1.0
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