If we know we have a folio, we can call get_folio() instead of get_page()
and save the overhead of calling compound_head().
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/mm.h | 16 +++++++++-------
1 file changed, 9 insertions(+), 7 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 80d38cc9561c..32ac5c14097d 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -1167,15 +1167,17 @@ static inline bool is_pci_p2pdma_page(const struct page *page)
#define page_ref_zero_or_close_to_overflow(page) \
((unsigned int) page_ref_count(page) + 127u <= 127u)
+static inline void get_folio(struct folio *folio)
+{
+ /* Getting a page requires an already elevated page->_refcount. */
+ VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(&folio->page),
+ &folio->page);
+ page_ref_inc(&folio->page);
+}
+
static inline void get_page(struct page *page)
{
- page = compound_head(page);
- /*
- * Getting a normal page or the head of a compound page
- * requires to already have an elevated page->_refcount.
- */
- VM_BUG_ON_PAGE(page_ref_zero_or_close_to_overflow(page), page);
- page_ref_inc(page);
+ get_folio(page_folio(page));
}
bool __must_check try_grab_page(struct page *page, unsigned int flags);
--
2.29.2
