From 974e6d66b6b5c6e2d6a3ccc18b2f9a0b472be5b4 Mon Sep 17 00:00:00 2001 From: Huang Ying Date: Fri, 17 Aug 2018 15:45:57 -0700 Subject: mm, hugetlbfs: pass fault address to cow handler This is to take better advantage of the general huge page copying optimization. Where, the target subpage will be copied last to avoid the cache lines of target subpage to be evicted when copying other subpages. This works better if the address of the target subpage is available when copying huge page. So hugetlbfs page fault handlers are changed to pass that information to hugetlb_cow(). This will benefit workloads which don't access the begin of the hugetlbfs huge page after the page fault under heavy cache contention. Link: http://lkml.kernel.org/r/20180524005851.4079-5-ying.huang@intel.com Signed-off-by: "Huang, Ying" Reviewed-by: Mike Kravetz Cc: Michal Hocko Cc: David Rientjes Cc: Andrea Arcangeli Cc: "Kirill A. Shutemov" Cc: Andi Kleen Cc: Jan Kara Cc: Matthew Wilcox Cc: Hugh Dickins Cc: Minchan Kim Cc: Shaohua Li Cc: Christopher Lameter Cc: "Aneesh Kumar K.V" Cc: Punit Agrawal Cc: Anshuman Khandual Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) (limited to 'mm/hugetlb.c') diff --git a/mm/hugetlb.c b/mm/hugetlb.c index e6767a35f7de..f1bcaae0d73a 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3509,7 +3509,7 @@ static void unmap_ref_private(struct mm_struct *mm, struct vm_area_struct *vma, * Keep the pte_same checks anyway to make transition from the mutex easier. */ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, - unsigned long haddr, pte_t *ptep, + unsigned long address, pte_t *ptep, struct page *pagecache_page, spinlock_t *ptl) { pte_t pte; @@ -3518,6 +3518,7 @@ static int hugetlb_cow(struct mm_struct *mm, struct vm_area_struct *vma, int ret = 0, outside_reserve = 0; unsigned long mmun_start; /* For mmu_notifiers */ unsigned long mmun_end; /* For mmu_notifiers */ + unsigned long haddr = address & huge_page_mask(h); pte = huge_ptep_get(ptep); old_page = pte_page(pte); @@ -3592,7 +3593,7 @@ retry_avoidcopy: goto out_release_all; } - copy_user_huge_page(new_page, old_page, haddr, vma, + copy_user_huge_page(new_page, old_page, address, vma, pages_per_huge_page(h)); __SetPageUptodate(new_page); set_page_huge_active(new_page); @@ -3826,7 +3827,7 @@ retry: hugetlb_count_add(pages_per_huge_page(h), mm); if ((flags & FAULT_FLAG_WRITE) && !(vma->vm_flags & VM_SHARED)) { /* Optimization, do the COW without a second fault */ - ret = hugetlb_cow(mm, vma, haddr, ptep, page, ptl); + ret = hugetlb_cow(mm, vma, address, ptep, page, ptl); } spin_unlock(ptl); @@ -3980,7 +3981,7 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, if (flags & FAULT_FLAG_WRITE) { if (!huge_pte_write(entry)) { - ret = hugetlb_cow(mm, vma, haddr, ptep, + ret = hugetlb_cow(mm, vma, address, ptep, pagecache_page, ptl); goto out_put_page; } -- cgit v1.2.3-55-g7522