On Tuesday, November 08, 2016 7:32 AM Naoya Horiguchi wrote:
>
> @@ -1013,6 +1027,9 @@ int do_huge_pmd_wp_page(struct fault_env *fe, pmd_t orig_pmd)
> if (unlikely(!pmd_same(*fe->pmd, orig_pmd)))
> goto out_unlock;
>
> + if (unlikely(!pmd_present(orig_pmd)))
> + goto out_unlock;
> +
Can we encounter a migration entry after acquiring ptl ?
> page = pmd_page(orig_pmd);
> VM_BUG_ON_PAGE(!PageCompound(page) || !PageHead(page), page);
> /*
[...]
> @@ -3591,6 +3591,10 @@ static int __handle_mm_fault(struct vm_area_struct *vma, unsigned long address,
> int ret;
>
> barrier();
> + if (unlikely(is_pmd_migration_entry(orig_pmd))) {
> + pmd_migration_entry_wait(mm, fe.pmd);
> + return 0;
> + }
> if (pmd_trans_huge(orig_pmd) || pmd_devmap(orig_pmd)) {
> if (pmd_protnone(orig_pmd) && vma_is_accessible(vma))
> return do_huge_pmd_numa_page(&fe, orig_pmd);
--
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