Commit 80371957 authored Dec 12, 2012 by Kirill A. Shutemov Committed by Linus Torvalds Dec 12, 2012

thp: setup huge zero page on non-write page fault



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 <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@linux.intel.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent c5a647d0

mm/huge_memory.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -733,6 +733,16 @@ 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))
		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)) {