From 4ddb4d91b82f4b64458fe35bc8e395c7c082ea2b Mon Sep 17 00:00:00 2001 From: Mike Kravetz Date: Tue, 21 Jun 2022 16:56:19 -0700 Subject: hugetlb: do not update address in huge_pmd_unshare As an optimization for loops sequentially processing hugetlb address ranges, huge_pmd_unshare would update a passed address if it unshared a pmd. Updating a loop control variable outside the loop like this is generally a bad idea. These loops are now using hugetlb_mask_last_page to optimize scanning when non-present ptes are discovered. The same can be done when huge_pmd_unshare returns 1 indicating a pmd was unshared. Remove address update from huge_pmd_unshare. Change the passed argument type and update all callers. In loops sequentially processing addresses use hugetlb_mask_last_page to update address if pmd is unshared. [sfr@canb.auug.org.au: fix an unused variable warning/error] Link: https://lkml.kernel.org/r/20220622171117.70850960@canb.auug.org.au Link: https://lkml.kernel.org/r/20220621235620.291305-4-mike.kravetz@oracle.com Signed-off-by: Mike Kravetz Signed-off-by: Stephen Rothwell Acked-by: Muchun Song Reviewed-by: Baolin Wang Cc: "Aneesh Kumar K.V" Cc: Anshuman Khandual Cc: Catalin Marinas Cc: Christian Borntraeger Cc: David Hildenbrand Cc: James Houghton Cc: kernel test robot Cc: Michal Hocko Cc: Mina Almasry Cc: Naoya Horiguchi Cc: Paul Walmsley Cc: Peter Xu Cc: Rolf Eike Beer Cc: Will Deacon Cc: Stephen Rothwell Signed-off-by: Andrew Morton --- include/linux/hugetlb.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include/linux') diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h index ce30fad5fd13..75ee739d815b 100644 --- a/include/linux/hugetlb.h +++ b/include/linux/hugetlb.h @@ -196,7 +196,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz); unsigned long hugetlb_mask_last_page(struct hstate *h); int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long *addr, pte_t *ptep); + 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, @@ -243,7 +243,7 @@ static inline struct address_space *hugetlb_page_mapping_lock_write( static inline int huge_pmd_unshare(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long *addr, pte_t *ptep) + unsigned long addr, pte_t *ptep) { return 0; } -- cgit