Re: [PATCH v4 3/5] mm, thp: introduce FOLL_SPLIT_PMD

[Kirill A. Shutemov]

On Thu, Jun 13, 2019 at 10:57:45AM -0700, Song Liu wrote:
> @@ -419,6 +419,11 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
>  			put_page(page);
>  			if (pmd_none(*pmd))
>  				return no_page_table(vma, flags);
> +		} else {  /* flags & FOLL_SPLIT_PMD */
> +			spin_unlock(ptl);
> +			ret = 0;
> +			split_huge_pmd(vma, pmd, address);
> +			pte_alloc(mm, pmd);

pte_alloc() can fail and the failure should be propogated to the caller.

-- 
 Kirill A. Shutemov