Thread (34 messages) 34 messages, 5 authors, 2012-10-26
STALE4991d
Revisions (6)
  1. rfc [diff vs current]
  2. v2 [diff vs current]
  3. v3 [diff vs current]
  4. v4 current
  5. v5 [diff vs current]
  6. v6 [diff vs current]

[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

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help