From f30c59e921f12b209852e1ddc197dc6a8fb0142b Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Wed, 5 Nov 2014 21:57:40 +0530 Subject: [PATCH] mm: Update generic gup implementation to handle hugepage directory Update generic gup implementation with powerpc specific details. On powerpc at pmd level we can have hugepte, normal pmd pointer or a pointer to the hugepage directory. Tested-by: Steve Capper Acked-by: Steve Capper Signed-off-by: Aneesh Kumar K.V Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/page.h | 1 + include/linux/hugetlb.h | 46 +++++++++++++++++++ mm/gup.c | 81 +++++++++++++++++++++++++++++---- 3 files changed, 120 insertions(+), 8 deletions(-) diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 26fe1ae15212..f973fce73a43 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -380,6 +380,7 @@ static inline int hugepd_ok(hugepd_t hpd) #endif #define is_hugepd(pdep) (hugepd_ok(*((hugepd_t *)(pdep)))) +#define pgd_huge pgd_huge int pgd_huge(pgd_t pgd); #else /* CONFIG_HUGETLB_PAGE */ #define is_hugepd(pdep) 0 diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 6e6d338641fe..e6b62f30ab21 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -175,6 +175,52 @@ static inline void __unmap_hugepage_range(struct mmu_gather *tlb, } #endif /* !CONFIG_HUGETLB_PAGE */ +/* + * hugepages at page global directory. If arch support + * hugepages at pgd level, they need to define this. + */ +#ifndef pgd_huge +#define pgd_huge(x) 0 +#endif + +#ifndef pgd_write +static inline int pgd_write(pgd_t pgd) +{ + BUG(); + return 0; +} +#endif + +#ifndef pud_write +static inline int pud_write(pud_t pud) +{ + BUG(); + return 0; +} +#endif + +#ifndef is_hugepd +/* + * Some architectures requires a hugepage directory format that is + * required to support multiple hugepage sizes. For example + * a4fe3ce76 "powerpc/mm: Allow more flexible layouts for hugepage pagetables" + * introduced the same on powerpc. This allows for a more flexible hugepage + * pagetable layout. + */ +typedef struct { unsigned long pd; } hugepd_t; +#define is_hugepd(hugepd) (0) +#define __hugepd(x) ((hugepd_t) { (x) }) +static inline int gup_huge_pd(hugepd_t hugepd, unsigned long addr, + unsigned pdshift, unsigned long end, + int write, struct page **pages, int *nr) +{ + return 0; +} +#else +extern int gup_huge_pd(hugepd_t hugepd, unsigned long addr, + unsigned pdshift, unsigned long end, + int write, struct page **pages, int *nr); +#endif #define HUGETLB_ANON_FILE "anon_hugepage" diff --git a/mm/gup.c b/mm/gup.c index cd62c8c90d4a..0ca1df9075ab 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -3,7 +3,6 @@ #include #include -#include #include #include #include @@ -12,6 +11,7 @@ #include #include +#include #include #include "internal.h" @@ -875,6 +875,49 @@ static int gup_huge_pud(pud_t orig, pud_t *pudp, unsigned long addr, return 1; } +static int gup_huge_pgd(pgd_t orig, pgd_t *pgdp, unsigned long addr, + unsigned long end, int write, + struct page **pages, int *nr) +{ + int refs; + struct page *head, *page, *tail; + + if (write && !pgd_write(orig)) + return 0; + + refs = 0; + head = pgd_page(orig); + page = head + ((addr & ~PGDIR_MASK) >> PAGE_SHIFT); + tail = page; + do { + VM_BUG_ON_PAGE(compound_head(page) != head, page); + pages[*nr] = page; + (*nr)++; + page++; + refs++; + } while (addr += PAGE_SIZE, addr != end); + + if (!page_cache_add_speculative(head, refs)) { + *nr -= refs; + return 0; + } + + if (unlikely(pgd_val(orig) != pgd_val(*pgdp))) { + *nr -= refs; + while (refs--) + put_page(head); + return 0; + } + + while (refs--) { + if (PageTail(tail)) + get_huge_page_tail(tail); + tail++; + } + + return 1; +} + static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, int write, struct page **pages, int *nr) { @@ -902,6 +945,14 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, pages, nr)) return 0; + } else if (unlikely(is_hugepd(__hugepd(pmd_val(pmd))))) { + /* + * architecture have different format for hugetlbfs + * pmd format and THP pmd format + */ + if (!gup_huge_pd(__hugepd(pmd_val(pmd)), addr, + PMD_SHIFT, next, write, pages, nr)) + return 0; } else if (!gup_pte_range(pmd, addr, next, write, pages, nr)) return 0; } while (pmdp++, addr = next, addr != end); @@ -909,22 +960,26 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end, return 1; } -static int gup_pud_range(pgd_t *pgdp, unsigned long addr, unsigned long end, - int write, struct page **pages, int *nr) +static int gup_pud_range(pgd_t pgd, unsigned long addr, unsigned long end, + int write, struct page **pages, int *nr) { unsigned long next; pud_t *pudp; - pudp = pud_offset(pgdp, addr); + pudp = pud_offset(&pgd, addr); do { pud_t pud = ACCESS_ONCE(*pudp); next = pud_addr_end(addr, end); if (pud_none(pud)) return 0; - if (pud_huge(pud)) { + if (unlikely(pud_huge(pud))) { if (!gup_huge_pud(pud, pudp, addr, next, write, - pages, nr)) + pages, nr)) + return 0; + } else if (unlikely(is_hugepd(__hugepd(pud_val(pud))))) { + if (!gup_huge_pd(__hugepd(pud_val(pud)), addr, + PUD_SHIFT, next, write, pages, nr)) return 0; } else if (!gup_pmd_range(pud, addr, next, write, pages, nr)) return 0; @@ -970,10 +1025,20 @@ int __get_user_pages_fast(unsigned long start, int nr_pages, int write, local_irq_save(flags); pgdp = pgd_offset(mm, addr); do { + pgd_t pgd = ACCESS_ONCE(*pgdp); + next = pgd_addr_end(addr, end); - if (pgd_none(*pgdp)) + if (pgd_none(pgd)) break; - else if (!gup_pud_range(pgdp, addr, next, write, pages, &nr)) + if (unlikely(pgd_huge(pgd))) { + if (!gup_huge_pgd(pgd, pgdp, addr, next, write, + pages, &nr)) + break; + } else if (unlikely(is_hugepd(__hugepd(pgd_val(pgd))))) { + if (!gup_huge_pd(__hugepd(pgd_val(pgd)), addr, + PGDIR_SHIFT, next, write, pages, &nr)) + break; + } else if (!gup_pud_range(pgd, addr, next, write, pages, &nr)) break; } while (pgdp++, addr = next, addr != end); local_irq_restore(flags);