On Wed, May 29, 2019 at 02:20:46PM -0700, Song Liu wrote:
> @@ -2133,10 +2133,15 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
> VM_BUG_ON_VMA(vma->vm_end < haddr + HPAGE_PMD_SIZE, vma);
> VM_BUG_ON(!is_pmd_migration_entry(*pmd) && !pmd_trans_huge(*pmd)
> && !pmd_devmap(*pmd));
> + /* only file backed vma need preallocate pgtable*/
> + VM_BUG_ON(vma_is_anonymous(vma) && prealloc_pgtable);
>
> count_vm_event(THP_SPLIT_PMD);
>
> - if (!vma_is_anonymous(vma)) {
> + if (prealloc_pgtable) {
> + pgtable_trans_huge_deposit(mm, pmd, prealloc_pgtable);
> + mm_inc_nr_pmds(mm);
> + } else if (!vma_is_anonymous(vma)) {
> _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
> /*
> * We are going to unmap this huge page. So
Nope. This going to leak a page table for architectures where
arch_needs_pgtable_deposit() is true.
--
Kirill A. Shutemov
