On 4 Apr 2022, at 15:30, Matthew Wilcox (Oracle) wrote:
> Simplify new_page() by unifying the THP and base page cases, and
> handle orders other than 0 and HPAGE_PMD_ORDER correctly.
>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
> ---
> mm/mempolicy.c | 25 +++++++++++--------------
> 1 file changed, 11 insertions(+), 14 deletions(-)
>
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index ec15f4f4b714..d6d7a95b0cce 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1191,8 +1191,10 @@ int do_migrate_pages(struct mm_struct *mm, const nodemask_t *from,
> */
> static struct page *new_page(struct page *page, unsigned long start)
> {
> + struct folio *dst, *src = page_folio(page);
> struct vm_area_struct *vma;
> unsigned long address;
> + gfp_t gfp = GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL;
>
> vma = find_vma(current->mm, start);
> while (vma) {
> @@ -1202,24 +1204,19 @@ static struct page *new_page(struct page *page, unsigned long start)
> vma = vma->vm_next;
> }
>
> - if (PageHuge(page)) {
> - return alloc_huge_page_vma(page_hstate(compound_head(page)),
> + if (folio_test_hugetlb(src)) {
> + return alloc_huge_page_vma(page_hstate(&src->page),
> vma, address);
> - } else if (PageTransHuge(page)) {
> - struct page *thp;
> -
> - thp = alloc_hugepage_vma(GFP_TRANSHUGE, vma, address,
> - HPAGE_PMD_ORDER);
> - if (!thp)
> - return NULL;
> - prep_transhuge_page(thp);
> - return thp;
> + } else if (folio_test_large(src)) {
> + gfp = GFP_TRANSHUGE;
> }
Nit. The two bracket pairs from the two ifs can be removed.
> +
> /*
> - * if !vma, alloc_page_vma() will use task or system default policy
> + * if !vma, vma_alloc_folio() will use task or system default policy
> */
> - return alloc_page_vma(GFP_HIGHUSER_MOVABLE | __GFP_RETRY_MAYFAIL,
> - vma, address);
> + dst = vma_alloc_folio(gfp, folio_order(src), vma, address,
> + folio_test_large(src));
> + return &dst->page;
> }
> #else
>
> --
> 2.34.1
--
Best Regards,
Yan, Zi
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