This implements the same algorithm as total_mapcount(), which is
transformed into a wrapper function.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
---
include/linux/mm.h | 8 +++++++-
mm/huge_memory.c | 24 ------------------------
mm/util.c | 33 +++++++++++++++++++++++++++++++++
3 files changed, 40 insertions(+), 25 deletions(-)
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 6ddf655f9279..6a19cd97d5aa 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -826,8 +826,14 @@ static inline int page_mapcount(struct page *page)
return atomic_read(&page->_mapcount) + 1;
}
+int folio_mapcount(struct folio *folio);
+
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-int total_mapcount(struct page *page);
+static inline int total_mapcount(struct page *page)
+{
+ return folio_mapcount(page_folio(page));
+}
+
int page_trans_huge_mapcount(struct page *page);
#else
static inline int total_mapcount(struct page *page)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 406a3c28c026..94e591d638eb 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2494,30 +2494,6 @@ static void __split_huge_page(struct page *page, struct list_head *list,
}
}
-int total_mapcount(struct page *page)
-{
- int i, compound, nr, ret;
-
- VM_BUG_ON_PAGE(PageTail(page), page);
-
- if (likely(!PageCompound(page)))
- return atomic_read(&page->_mapcount) + 1;
-
- compound = compound_mapcount(page);
- nr = compound_nr(page);
- if (PageHuge(page))
- return compound;
- ret = compound;
- for (i = 0; i < nr; i++)
- ret += atomic_read(&page[i]._mapcount) + 1;
- /* File pages has compound_mapcount included in _mapcount */
- if (!PageAnon(page))
- return ret - compound * nr;
- if (PageDoubleMap(page))
- ret -= nr;
- return ret;
-}
-
/*
* This calculates accurately how many mappings a transparent hugepage
* has (unlike page_mapcount() which isn't fully accurate). This full
diff --git a/mm/util.c b/mm/util.c
index 7e43369064c8..b614f423aaa4 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -740,6 +740,39 @@ int __page_mapcount(struct page *page)
}
EXPORT_SYMBOL_GPL(__page_mapcount);
+/**
+ * folio_mapcount() - Calculate the number of mappings of this folio.
+ * @folio: The folio.
+ *
+ * A large folio tracks both how many times the entire folio is mapped,
+ * and how many times each individual page in the folio is mapped.
+ * This function calculates the total number of times the folio is
+ * mapped.
+ *
+ * Return: The number of times this folio is mapped.
+ */
+int folio_mapcount(struct folio *folio)
+{
+ int i, compound, nr, ret;
+
+ if (likely(!folio_test_large(folio)))
+ return atomic_read(&folio->_mapcount) + 1;
+
+ compound = folio_entire_mapcount(folio);
+ nr = folio_nr_pages(folio);
+ if (folio_test_hugetlb(folio))
+ return compound;
+ ret = compound;
+ for (i = 0; i < nr; i++)
+ ret += atomic_read(&folio_page(folio, i)->_mapcount) + 1;
+ /* File pages has compound_mapcount included in _mapcount */
+ if (!folio_test_anon(folio))
+ return ret - compound * nr;
+ if (folio_test_double_map(folio))
+ ret -= nr;
+ return ret;
+}
+
/**
* folio_copy - Copy the contents of one folio to another.
* @dst: Folio to copy to.
--
2.34.1
