From 31d49da5ad01728e48a1bb2b43795598b23de68a Mon Sep 17 00:00:00 2001 From: "Aneesh Kumar K.V" Date: Tue, 26 Jul 2016 15:24:06 -0700 Subject: [PATCH] mm/hugetlb: simplify hugetlb unmap For hugetlb like THP (and unlike regular page), we do tlb flush after dropping ptl. Because of the above, we don't need to track force_flush like we do now. Instead we can simply call tlb_remove_page() which will do the flush if needed. No functionality change in this patch. Link: http://lkml.kernel.org/r/1465049193-22197-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com Signed-off-by: Aneesh Kumar K.V Cc: Benjamin Herrenschmidt Cc: Paul Mackerras Cc: Michael Ellerman Cc: "Kirill A. Shutemov" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/hugetlb.c | 54 ++++++++++++++++++++-------------------------------- 1 file changed, 21 insertions(+), 33 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index addfe4accc07..524c078ce67b 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3177,7 +3177,6 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start, unsigned long end, struct page *ref_page) { - int force_flush = 0; struct mm_struct *mm = vma->vm_mm; unsigned long address; pte_t *ptep; @@ -3196,19 +3195,22 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma, tlb_start_vma(tlb, vma); mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); address = start; -again: for (; address < end; address += sz) { ptep = huge_pte_offset(mm, address); if (!ptep) continue; ptl = huge_pte_lock(h, mm, ptep); - if (huge_pmd_unshare(mm, &address, ptep)) - goto unlock; + if (huge_pmd_unshare(mm, &address, ptep)) { + spin_unlock(ptl); + continue; + } pte = huge_ptep_get(ptep); - if (huge_pte_none(pte)) - goto unlock; + if (huge_pte_none(pte)) { + spin_unlock(ptl); + continue; + } /* * Migrating hugepage or HWPoisoned hugepage is already @@ -3216,7 +3218,8 @@ again: */ if (unlikely(!pte_present(pte))) { huge_pte_clear(mm, address, ptep); - goto unlock; + spin_unlock(ptl); + continue; } page = pte_page(pte); @@ -3226,9 +3229,10 @@ again: * are about to unmap is the actual page of interest. */ if (ref_page) { - if (page != ref_page) - goto unlock; - + if (page != ref_page) { + spin_unlock(ptl); + continue; + } /* * Mark the VMA as having unmapped its page so that * future faults in this VMA will fail rather than @@ -3244,30 +3248,14 @@ again: hugetlb_count_sub(pages_per_huge_page(h), mm); page_remove_rmap(page, true); - force_flush = !__tlb_remove_page(tlb, page); - if (force_flush) { - address += sz; - spin_unlock(ptl); - break; - } - /* Bail out after unmapping reference page if supplied */ - if (ref_page) { - spin_unlock(ptl); - break; - } -unlock: + spin_unlock(ptl); - } - /* - * mmu_gather ran out of room to batch pages, we break out of - * the PTE lock to avoid doing the potential expensive TLB invalidate - * and page-free while holding it. - */ - if (force_flush) { - force_flush = 0; - tlb_flush_mmu(tlb); - if (address < end && !ref_page) - goto again; + tlb_remove_page(tlb, page); + /* + * Bail out after unmapping reference page if supplied + */ + if (ref_page) + break; } mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); tlb_end_vma(tlb, vma); -- 2.20.1