[PATCH v6 14/27] mm: Add folio_mapcount
From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Date: 2021-03-31 18:54:40
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> --- include/linux/mm.h | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index a4f2818aeb1d..fc15a256e686 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h@@ -869,6 +869,22 @@ 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(FolioMulti(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