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mm/gup: Convert gup_pte_range() to use a folio

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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>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
This commit is contained in:
Matthew Wilcox (Oracle) 2021-12-10 15:54:11 -05:00
parent 822951d846
commit b0496fe4ef
1 changed files with 8 additions and 10 deletions
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18
mm/gup.c
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@ -2232,7 +2232,8 @@ 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
@ -2259,22 +2260,20 @@ 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
@ -2284,14 +2283,13 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
if (flags & FOLL_PIN) {
ret = arch_make_page_accessible(page);
if (ret) {
unpin_user_page(page);
gup_put_folio(folio, 1, flags);
goto pte_unmap;
}
}
SetPageReferenced(page);
folio_set_referenced(folio);
pages[*nr] = page;
(*nr)++;
} while (ptep++, addr += PAGE_SIZE, addr != end);
ret = 1;