Re: [PATCH v5 08/11] thp: setup huge zero page on non-write page fault

David Rientjes
2012-11-14T23:33:19Z

On Wed, 7 Nov 2012, Kirill A. Shutemov wrote:

> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index f36bc7d..41f05f1 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -726,6 +726,16 @@ 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;

No use in retrying, just return VM_FAULT_OOM.

> + 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)) {