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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2012-12-12 13:51:02 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-12-12 17:38:31 -0800
commit80371957f09814d25c38733d2d08de47f59a13c2 (patch)
tree2ebdedfa3a10af22941e44729f1c4c2623e8da74 /mm/huge_memory.c
parentc5a647d09fe9fc3e0241c89845cf8e6220b916f5 (diff)
downloadop-kernel-dev-80371957f09814d25c38733d2d08de47f59a13c2.zip
op-kernel-dev-80371957f09814d25c38733d2d08de47f59a13c2.tar.gz
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>
Diffstat (limited to 'mm/huge_memory.c')
-rw-r--r--mm/huge_memory.c10
1 files changed, 10 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index ea0e23f..e1b6f4e 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -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)) {
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