[PATCHv6 17/30] vmscan: split file huge pages before paging them out

[Kirill A. Shutemov]

This is preparation of vmscan for file huge pages. We cannot write out
huge pages, so we need to split them on the way out.

Signed-off-by: Kirill A. Shutemov <kirill.shute...@linux.intel.com>
---
 mm/vmscan.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/mm/vmscan.c b/mm/vmscan.c
index b934223eaa45..4cc96ba44a34 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1055,8 +1055,14 @@ static unsigned long 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))
+                               goto keep_locked;
                }
 
+               VM_BUG_ON_PAGE(PageTransHuge(page), page);
+
                /*
                 * The page is mapped into the page tables of one or more
                 * processes. Try to unmap it here.
-- 
2.8.0.rc3