[PATCHv6 09/30] thp: handle file pages in split_huge_pmd()

[Kirill A. Shutemov]

Splitting THP PMD is simple: just unmap it as in DAX case.
Unlike DAX, we also remove the page from rmap and drop reference.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
 mm/huge_memory.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 5975c14d66ab..729e73356b97 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2943,10 +2943,16 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd,
 
 	count_vm_event(THP_SPLIT_PMD);
 
-	if (vma_is_dax(vma)) {
-		pmd_t _pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
+	if (!vma_is_anonymous(vma)) {
+		_pmd = pmdp_huge_clear_flush_notify(vma, haddr, pmd);
 		if (is_huge_zero_pmd(_pmd))
 			put_huge_zero_page();
+		if (vma_is_dax(vma))
+			return;
+		page = pmd_page(_pmd);
+		page_remove_rmap(page, true);
+		put_page(page);
+		add_mm_counter(mm, MM_FILEPAGES, -HPAGE_PMD_NR);
 		return;
 	} else if (is_huge_zero_pmd(*pmd)) {
 		return __split_huge_zero_page_pmd(vma, haddr, pmd);
-- 
2.8.0.rc3