diff options
| -rw-r--r-- | mm/huge_memory.c | 43 |
1 files changed, 42 insertions, 1 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c index de6aa5f3fdd2..ea0e23fd6967 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1616,6 +1616,7 @@ int split_huge_page(struct page *page) struct anon_vma *anon_vma; int ret = 1; + BUG_ON(is_huge_zero_pfn(page_to_pfn(page))); BUG_ON(!PageAnon(page)); anon_vma = page_lock_anon_vma(page); if (!anon_vma) @@ -2475,24 +2476,64 @@ static int khugepaged(void *none) return 0; } +static void __split_huge_zero_page_pmd(struct vm_area_struct *vma, + unsigned long haddr, pmd_t *pmd) +{ + struct mm_struct *mm = vma->vm_mm; + pgtable_t pgtable; + pmd_t _pmd; + int i; + + pmdp_clear_flush(vma, haddr, pmd); + /* leave pmd empty until pte is filled */ + + pgtable = pgtable_trans_huge_withdraw(mm); + pmd_populate(mm, &_pmd, pgtable); + + for (i = 0; i < HPAGE_PMD_NR; i++, haddr += PAGE_SIZE) { + pte_t *pte, entry; + entry = pfn_pte(my_zero_pfn(haddr), vma->vm_page_prot); + entry = pte_mkspecial(entry); + pte = pte_offset_map(&_pmd, haddr); + VM_BUG_ON(!pte_none(*pte)); + set_pte_at(mm, haddr, pte, entry); + pte_unmap(pte); + } + smp_wmb(); /* make pte visible before pmd */ + pmd_populate(mm, pmd, pgtable); +} + void __split_huge_page_pmd(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd) { struct page *page; - unsigned long haddr = address & HPAGE_PMD_MASK; struct mm_struct *mm = vma->vm_mm; + unsigned long haddr = address & HPAGE_PMD_MASK; + unsigned long mmun_start; /* For mmu_notifiers */ + unsigned long mmun_end; /* For mmu_notifiers */ BUG_ON(vma->vm_start > haddr || vma->vm_end < haddr + HPAGE_PMD_SIZE); + mmun_start = haddr; + mmun_end = haddr + HPAGE_PMD_SIZE; + mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); spin_lock(&mm->page_table_lock); if (unlikely(!pmd_trans_huge(*pmd))) { spin_unlock(&mm->page_table_lock); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); + return; + } + if (is_huge_zero_pmd(*pmd)) { + __split_huge_zero_page_pmd(vma, haddr, pmd); + spin_unlock(&mm->page_table_lock); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); return; } page = pmd_page(*pmd); VM_BUG_ON(!page_count(page)); get_page(page); spin_unlock(&mm->page_table_lock); + mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); split_huge_page(page); |