| Date | Mon, 10 Jan 2022 23:06:05 -0800 | Subject | Re: [PATCH v2 20/28] gup: Convert gup_pte_range() to use a folio | From | John Hubbard <> |
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On 1/9/22 20:23, Matthew Wilcox (Oracle) wrote: > We still call try_grab_folio() once per PTE; a future patch could > optimise to just adjust the reference count for each page within > the folio. > > Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> > --- > mm/gup.c | 16 +++++++--------- > 1 file changed, 7 insertions(+), 9 deletions(-)
Still looks good.
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
thanks, -- John Hubbard NVIDIA
> > diff --git a/mm/gup.c b/mm/gup.c > index c3e514172eaf..27cc097ec05d 100644 > --- a/mm/gup.c > +++ b/mm/gup.c > @@ -2235,7 +2235,8 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, > ptem = ptep = pte_offset_map(&pmd, addr); > do { > pte_t pte = ptep_get_lockless(ptep); > - struct page *head, *page; > + struct page *page; > + struct folio *folio; > > /* > * Similar to the PMD case below, NUMA hinting must take slow > @@ -2262,22 +2263,20 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, > VM_BUG_ON(!pfn_valid(pte_pfn(pte))); > page = pte_page(pte); > > - head = try_grab_compound_head(page, 1, flags); > - if (!head) > + folio = try_grab_folio(page, 1, flags); > + if (!folio) > goto pte_unmap; > > if (unlikely(page_is_secretmem(page))) { > - put_compound_head(head, 1, flags); > + gup_put_folio(folio, 1, flags); > goto pte_unmap; > } > > if (unlikely(pte_val(pte) != pte_val(*ptep))) { > - put_compound_head(head, 1, flags); > + gup_put_folio(folio, 1, flags); > goto pte_unmap; > } > > - VM_BUG_ON_PAGE(compound_head(page) != head, page); > - > /* > * We need to make the page accessible if and only if we are > * going to access its content (the FOLL_PIN case). Please > @@ -2291,10 +2290,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end, > goto pte_unmap; > } > } > - SetPageReferenced(page); > + folio_set_referenced(folio); > pages[*nr] = page; > (*nr)++; > - > } while (ptep++, addr += PAGE_SIZE, addr != end); > > ret = 1;
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