split_huge_pmd() for file mappings (and DAX too) is implemented by just
clearing pmd entry as we can re-fill this area from page cache on pte
level later.
This means we don't need deposit page tables when file THP is mapped.
Therefore we shouldn't try to withdraw a page table on zap_huge_pmd()
file THP PMD.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 810ce20c3af6..2e838795aab1 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1695,10 +1695,16 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct page *page = pmd_page(orig_pmd);
page_remove_rmap(page, true);
VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
- add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
VM_BUG_ON_PAGE(!PageHead(page), page);
- pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
- atomic_long_dec(&tlb->mm->nr_ptes);
+ if (PageAnon(page)) {
+ pgtable_t pgtable;
+ pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
+ pte_free(tlb->mm, pgtable);
+ atomic_long_dec(&tlb->mm->nr_ptes);
+ add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+ } else {
+ add_mm_counter(tlb->mm, MM_FILEPAGES, -HPAGE_PMD_NR);
+ }
spin_unlock(ptl);
tlb_remove_page(tlb, page);
}
--
2.8.1
--
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