[PATCH v10 16/33] mm: Add folio_mapcount
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: 2021-05-11 21:59:48
Also in:
linux-fsdevel, lkml
Subsystem:
memory management - core, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
This is the folio equivalent of page_mapcount(). Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Jeff Layton <jlayton@kernel.org> --- include/linux/mm.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index dca39daf3495..6e3dde81ecc9 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -883,6 +883,22 @@ static inline int page_mapcount(struct page *page) return atomic_read(&page->_mapcount) + 1; } +/** + * folio_mapcount - The number of mappings of this folio. + * @folio: The folio. + * + * The result includes the number of times any of the pages in the + * folio are mapped to userspace. + * + * Return: The number of page table entries which refer to this folio. + */ +static inline int folio_mapcount(struct folio *folio) +{ + if (unlikely(folio_multi(folio))) + return __page_mapcount(&folio->page); + return atomic_read(&folio->_mapcount) + 1; +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE int total_mapcount(struct page *page); int page_trans_huge_mapcount(struct page *page, int *total_mapcount);
--
2.30.2