diff options
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/mm/memory.c b/mm/memory.c index e046b7e4b530..788a62810340 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -498,6 +498,17 @@ int copy_page_range(struct mm_struct *dst_mm, struct mm_struct *src_mm, unsigned long addr = vma->vm_start; unsigned long end = vma->vm_end; + /* + * Don't copy ptes where a page fault will fill them correctly. + * Fork becomes much lighter when there are big shared or private + * readonly mappings. The tradeoff is that copy_page_range is more + * efficient than faulting. + */ + if (!(vma->vm_flags & (VM_HUGETLB|VM_NONLINEAR|VM_RESERVED))) { + if (!vma->anon_vma) + return 0; + } + if (is_vm_hugetlb_page(vma)) return copy_hugetlb_page_range(dst_mm, src_mm, vma); @@ -551,7 +562,8 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, page->index > details->last_index)) continue; } - ptent = ptep_get_and_clear(tlb->mm, addr, pte); + ptent = ptep_get_and_clear_full(tlb->mm, addr, pte, + tlb->fullmm); tlb_remove_tlb_entry(tlb, pte, addr); if (unlikely(!page)) continue; @@ -579,7 +591,7 @@ static void zap_pte_range(struct mmu_gather *tlb, pmd_t *pmd, continue; if (!pte_file(ptent)) free_swap_and_cache(pte_to_swp_entry(ptent)); - pte_clear(tlb->mm, addr, pte); + pte_clear_full(tlb->mm, addr, pte, tlb->fullmm); } while (pte++, addr += PAGE_SIZE, addr != end); pte_unmap(pte - 1); } @@ -1944,7 +1956,7 @@ static int do_file_page(struct mm_struct * mm, struct vm_area_struct * vma, * Fall back to the linear mapping if the fs does not support * ->populate: */ - if (!vma->vm_ops || !vma->vm_ops->populate || + if (!vma->vm_ops->populate || (write_access && !(vma->vm_flags & VM_SHARED))) { pte_clear(mm, address, pte); return do_no_page(mm, vma, address, write_access, pte, pmd); |