From 57a196a58421a4b0c45949ae7309f21829aaa77f Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Sun, 18 Sep 2022 19:13:48 -0700 Subject: hugetlb: simplify hugetlb handling in follow_page_mask During discussions of this series [1], it was suggested that hugetlb handling code in follow_page_mask could be simplified. At the beginning of follow_page_mask, there currently is a call to follow_huge_addr which 'may' handle hugetlb pages. ia64 is the only architecture which provides a follow_huge_addr routine that does not return error. Instead, at each level of the page table a check is made for a hugetlb entry. If a hugetlb entry is found, a call to a routine associated with that entry is made. Currently, there are two checks for hugetlb entries at each page table level. The first check is of the form: if (p?d_huge()) page = follow_huge_p?d(); the second check is of the form: if (is_hugepd()) page = follow_huge_pd(). We can replace these checks, as well as the special handling routines such as follow_huge_p?d() and follow_huge_pd() with a single routine to handle hugetlb vmas. A new routine hugetlb_follow_page_mask is called for hugetlb vmas at the beginning of follow_page_mask. hugetlb_follow_page_mask will use the existing routine huge_pte_offset to walk page tables looking for hugetlb entries. huge_pte_offset can be overwritten by architectures, and already handles special cases such as hugepd entries. [1] https://lore.kernel.org/linux-mm/cover.1661240170.git.baolin.wang@linux.alibaba.com/ [mike.kravetz@oracle.com: remove vma (pmd sharing) per Peter] Link: https://lkml.kernel.org/r/20221028181108.119432-1-mike.kravetz@oracle.com [mike.kravetz@oracle.com: remove left over hugetlb_vma_unlock_read()] Link: https://lkml.kernel.org/r/20221030225825.40872-1-mike.kravetz@oracle.com Link: https://lkml.kernel.org/r/20220919021348.22151-1-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Suggested-by: David Hildenbrand Reviewed-by: David Hildenbrand Reviewed-by: Baolin Wang Tested-by: Baolin Wang Cc: Aneesh Kumar K.V Cc: Christophe Leroy Cc: Michael Ellerman Cc: Muchun Song Cc: Naoya Horiguchi Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 50 ++++++++----------------------------------------- 1 file changed, 8 insertions(+), 42 deletions(-) (limited to 'include') diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index 8b4f93e84868..4a76c0fc6bbf 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -149,6 +149,8 @@ int move_hugetlb_page_tables(struct vm_area_struct *vma, unsigned long len); int copy_hugetlb_page_range(struct mm_struct *, struct mm_struct *, struct vm_area_struct *, struct vm_area_struct *); +struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, + unsigned long address, unsigned int flags); long follow_hugetlb_page(struct mm_struct *, struct vm_area_struct *, struct page **, struct vm_area_struct **, unsigned long *, unsigned long *, long, unsigned int, @@ -209,17 +211,6 @@ int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, unsigned long addr, pte_t *ptep); void adjust_range_if_pmd_sharing_possible(struct vm_area_struct *vma, unsigned long *start, unsigned long *end); -struct page *follow_huge_addr(struct mm_struct *mm, unsigned long address, - int write); -struct page *follow_huge_pd(struct vm_area_struct *vma, - unsigned long address, hugepd_t hpd, - int flags, int pdshift); -struct page *follow_huge_pmd_pte(struct vm_area_struct *vma, unsigned long address, - 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); void hugetlb_vma_lock_read(struct vm_area_struct *vma); void hugetlb_vma_unlock_read(struct vm_area_struct *vma); @@ -272,6 +263,12 @@ static inline void adjust_range_if_pmd_sharing_possible( { } +static inline struct page *hugetlb_follow_page_mask(struct vm_area_struct *vma, + unsigned long address, unsigned int flags) +{ + BUILD_BUG(); /* should never be compiled in if !CONFIG_HUGETLB_PAGE*/ +} + static inline long follow_hugetlb_page(struct mm_struct *mm, struct vm_area_struct *vma, struct page **pages, struct vm_area_struct **vmas, unsigned long *position, @@ -282,12 +279,6 @@ static inline long follow_hugetlb_page(struct mm_struct *mm, return 0; } -static inline struct page *follow_huge_addr(struct mm_struct *mm, - unsigned long address, int write) -{ - return ERR_PTR(-EINVAL); -} - static inline int copy_hugetlb_page_range(struct mm_struct *dst, struct mm_struct *src, struct vm_area_struct *dst_vma, @@ -320,31 +311,6 @@ static inline void hugetlb_show_meminfo_node(int nid) { } -static inline struct page *follow_huge_pd(struct vm_area_struct *vma, - unsigned long address, hugepd_t hpd, int flags, - int pdshift) -{ - return NULL; -} - -static inline struct page *follow_huge_pmd_pte(struct vm_area_struct *vma, - unsigned long address, int flags) -{ - return NULL; -} - -static inline struct page *follow_huge_pud(struct mm_struct *mm, - unsigned long address, pud_t *pud, int flags) -{ - return NULL; -} - -static inline struct page *follow_huge_pgd(struct mm_struct *mm, - unsigned long address, pgd_t *pgd, int flags) -{ - return NULL; -} - static inline int prepare_hugepage_range(struct file *file, unsigned long addr, unsigned long len) { -- cgit v1.2.3