From: "Kirill A. Shutemov" <kirill.shutemov@xxxxxxxxxxxxxxx>
All code paths seems covered. Now we can map huge zero page on read page
fault.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Reviewed-by: Andrea Arcangeli <aarcange@xxxxxxxxxx>
---
mm/huge_memory.c | 10 ++++++++++
1 files changed, 10 insertions(+), 0 deletions(-)
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 3f1c59c..a5b9282 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -751,6 +751,16 @@ int do_huge_pmd_anonymous_page(struct mm_struct *mm, struct vm_area_struct *vma,
return VM_FAULT_OOM;
if (unlikely(khugepaged_enter(vma)))
return VM_FAULT_OOM;
+ if (!(flags & FAULT_FLAG_WRITE)) {
+ pgtable_t pgtable;
+ pgtable = pte_alloc_one(mm, haddr);
+ if (unlikely(!pgtable))
+ goto out;
+ spin_lock(&mm->page_table_lock);
+ set_huge_zero_page(pgtable, mm, vma, haddr, pmd);
+ spin_unlock(&mm->page_table_lock);
+ return 0;
+ }
page = alloc_hugepage_vma(transparent_hugepage_defrag(vma),
vma, haddr, numa_node_id(), 0);
if (unlikely(!page)) {
--
1.7.7.6
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