Let's return early for hugetlb, which really only relies on the compound
mapcount so far and does not support PageDoubleMap() yet. Use the chance
to cleanup the file-THP case to make it easier to grasp. While at it, use
head_compound_mapcount().
This is a preparation for further changes.
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
---
mm/util.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)
diff --git a/mm/util.c b/mm/util.c
index 741ba32a43ac..3239e75c148d 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -732,15 +732,18 @@ int __page_mapcount(struct page *page)
{
int ret;
- ret = atomic_read(&page->_mapcount) + 1;
+ if (PageHuge(page))
+ return compound_mapcount(page);
/*
* For file THP page->_mapcount contains total number of mapping
* of the page: no need to look into compound_mapcount.
*/
- if (!PageAnon(page) && !PageHuge(page))
- return ret;
+ if (!PageAnon(page))
+ return atomic_read(&page->_mapcount) + 1;
+
+ ret = atomic_read(&page->_mapcount) + 1;
page = compound_head(page);
- ret += atomic_read(compound_mapcount_ptr(page)) + 1;
+ ret += head_compound_mapcount(page);
if (PageDoubleMap(page))
ret--;
return ret;
--
2.31.1
