[RFC 2/9] mm/hugetlb: Add follow_huge_pgd function
From: Anshuman Khandual <hidden>
Date: 2016-03-09 12:11:57
Also in:
linux-mm, lkml
Subsystem:
hugetlb subsystem, memory management, the rest · Maintainers:
Muchun Song, Oscar Salvador, Andrew Morton, Linus Torvalds
This just adds 'follow_huge_pgd' function which is will be used later in this series to make 'follow_page_mask' function aware of PGD based huge page implementation. Signed-off-by: Anshuman Khandual <redacted> --- include/linux/hugetlb.h | 3 +++ mm/hugetlb.c | 10 ++++++++++ 2 files changed, 13 insertions(+)
diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h
index 7d953c2..71832e1 100644
--- a/include/linux/hugetlb.h
+++ b/include/linux/hugetlb.h@@ -115,6 +115,8 @@ struct page *follow_huge_pmd(struct mm_struct *mm, unsigned long address, pmd_t *pmd, int flags); struct page *follow_huge_pud(struct mm_struct *mm, unsigned long address, pud_t *pud, int flags); +struct page *follow_huge_pgd(struct mm_struct *mm, unsigned long address, + pgd_t *pgd, int flags); int pmd_huge(pmd_t pmd); int pud_huge(pud_t pmd); unsigned long hugetlb_change_protection(struct vm_area_struct *vma,
@@ -143,6 +145,7 @@ static inline void hugetlb_show_meminfo(void) } #define follow_huge_pmd(mm, addr, pmd, flags) NULL #define follow_huge_pud(mm, addr, pud, flags) NULL +#define follow_huge_pgd(mm, addr, pgd, flags) NULL #define prepare_hugepage_range(file, addr, len) (-EINVAL) #define pmd_huge(x) 0 #define pud_huge(x) 0
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index a478b7b..844c18f 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c@@ -4353,6 +4353,16 @@ follow_huge_pud(struct mm_struct *mm, unsigned long address, return pte_page(*(pte_t *)pud) + ((address & ~PUD_MASK) >> PAGE_SHIFT); } +struct page * __weak +follow_huge_pgd(struct mm_struct *mm, unsigned long address, + pgd_t *pgd, int flags) +{ + if (flags & FOLL_GET) + return NULL; + + return pte_page(*(pte_t *)pgd) + ((address & ~PGDIR_MASK) >> PAGE_SHIFT); +} + #ifdef CONFIG_MEMORY_FAILURE /*
--
2.1.0