[PATCHv7 09/29] 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.shute...@linux.intel.com>
---
 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 29ba922a9c26..67830a6ed8b0 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2940,10 +2940,16 @@ 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