From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
We don't have a real page to zap in huge zero page case. Let's just
clear pmd and remove it from tlb.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
---
mm/huge_memory.c | 27 +++++++++++++++++----------
1 files changed, 17 insertions(+), 10 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 88e0a7a..9dcb9e6 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1071,16 +1071,23 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
struct page *page;
pgtable_t pgtable;
pgtable = get_pmd_huge_pte(tlb->mm);
- page = pmd_page(*pmd);
- pmd_clear(pmd);
- tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
- page_remove_rmap(page);
- VM_BUG_ON(page_mapcount(page) < 0);
- add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
- VM_BUG_ON(!PageHead(page));
- tlb->mm->nr_ptes--;
- spin_unlock(&tlb->mm->page_table_lock);
- tlb_remove_page(tlb, page);
+ if (is_huge_zero_pmd(*pmd)) {
+ pmd_clear(pmd);
+ tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+ tlb->mm->nr_ptes--;
+ spin_unlock(&tlb->mm->page_table_lock);
+ } else {
+ page = pmd_page(*pmd);
+ pmd_clear(pmd);
+ tlb_remove_pmd_tlb_entry(tlb, pmd, addr);
+ page_remove_rmap(page);
+ VM_BUG_ON(page_mapcount(page) < 0);
+ add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
+ VM_BUG_ON(!PageHead(page));
+ tlb->mm->nr_ptes--;
+ spin_unlock(&tlb->mm->page_table_lock);
+ tlb_remove_page(tlb, page);
+ }
pte_free(tlb->mm, pgtable);
ret = 1;
}
--
1.7.7.6
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