[PATCH v4 08/10] thp: setup huge zero page on non-write page fault
From: Kirill A. Shutemov <hidden>
Date: 2012-10-15 06:00:40
Also in:
lkml
Subsystem:
memory management, memory management - thp (transparent huge page), the rest · Maintainers:
Andrew Morton, David Hildenbrand, Lorenzo Stoakes, Linus Torvalds
From: "Kirill A. Shutemov" <redacted> All code paths seems covered. Now we can map huge zero page on read page fault. We setup it in do_huge_pmd_anonymous_page() if area around fault address is suitable for THP and we've got read page fault. If we fail to setup huge zero page (ENOMEM) we fallback to handle_pte_fault() as we normally do in THP. Signed-off-by: Kirill A. Shutemov <redacted> --- 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 b267b12..da7e07b 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c@@ -725,6 +725,16 @@ 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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