[PATCH v6 40/51] mm: Avoid splitting THPs

[Matthew Wilcox]

From: "Matthew Wilcox (Oracle)" <wi...@infradead.org>

If the filesystem supports THPs, then do not split them before
removing them from the page cache; remove them as a unit.
---
 mm/vmscan.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index 17934e03b3aa..0db62c1001f7 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1277,9 +1277,9 @@ static unsigned int shrink_page_list(struct list_head 
*page_list,
                                /* Adding to swap updated mapping */
                                mapping = page_mapping(page);
                        }
-               } else if (unlikely(PageTransHuge(page))) {
-                       /* Split file THP */
-                       if (split_huge_page_to_list(page, page_list))
+               } else if (PageTransHuge(page)) {
+                       if ((!mapping || !mapping_thp_support(mapping)) &&
+                           split_huge_page_to_list(page, page_list))
                                goto keep_locked;
                }
 
-- 
2.26.2