On 1/2/22 13:57, 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@xxxxxxxxxxxxx>
---
mm/gup.c | 16 +++++++---------
1 file changed, 7 insertions(+), 9 deletions(-)
diff --git a/mm/gup.c b/mm/gup.c
index 2307b2917055..d8535f9d5622 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -2260,7 +2260,8 @@ 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
@@ -2287,22 +2288,20 @@ 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
@@ -2316,10 +2315,9 @@ static int gup_pte_range(pmd_t pmd, unsigned long addr, unsigned long end,
goto pte_unmap;
}
}
- SetPageReferenced(page);
+ folio_set_referenced(folio);
For the case of a tail page, I *think* the above hunk changes the
behavior. Previously, the tail page's flags were affected, but now, the
head page's (folio's) page flags are being changed...right?
thanks,
--
John Hubbard
NVIDIA
pages[*nr] = page;
(*nr)++;
-
} while (ptep++, addr += PAGE_SIZE, addr != end);
ret = 1;
