[PATCH 8/9] thp: handle file pages in split_huge_pmd()

From: Kirill A. Shutemov
Date: Wed Nov 18 2015 - 18:26:24 EST


Splitting THP PMD is simple: just unmap it as in DAX case.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 661e144a619d..acd367b04730 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2774,10 +2774,14 @@ 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_remove_rmap(pmd_page(_pmd), true);
+ 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);
--
2.6.2

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