[PATCH 12/15] mm: Support removing arbitrary sized pages from mapping

Matthew Wilcox
2019-09-25T00:53:14Z

From: William Kucharski <william.kucharski@oracle.com>

__remove_mapping() assumes that pages can only be either base pages
or HPAGE_PMD_SIZE. Ask the page what size it is.

Signed-off-by: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
mm/vmscan.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index a7f9f379e523..9f44868e640b 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -932,10 +932,7 @@ static int __remove_mapping(struct address_space *mapping, struct page *page,
* Note that if SetPageDirty is always performed via set_page_dirty,
* and thus under the i_pages lock, then this ordering is not required.
*/
- if (unlikely(PageTransHuge(page)) && PageSwapCache(page))
- refcount = 1 + HPAGE_PMD_NR;
- else
- refcount = 2;
+ refcount = 1 + compound_nr(page);
if (!page_ref_freeze(page, refcount))
goto cannot_free;
/* note: atomic_cmpxchg in page_ref_freeze provides the smp_rmb */
--
2.23.0