3 files changed, 68 insertions, 0 deletions

diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h
index d9ab70d776e..43a694ef890 100644
--- a/include/linux/huge_mm.h
+++ b/include/linux/huge_mm.h
@@ -25,6 +25,7 @@ enum transparent_hugepage_flag {
         TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG,
         TRANSPARENT_HUGEPAGE_DEFRAG_FLAG,
         TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG,
+        TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG,
 #ifdef CONFIG_DEBUG_VM
         TRANSPARENT_HUGEPAGE_DEBUG_COW_FLAG,
 #endif
diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h
new file mode 100644
index 00000000000..552f3184756
--- /dev/null
+++ b/include/linux/khugepaged.h
@@ -0,0 +1,66 @@
+#ifndef _LINUX_KHUGEPAGED_H
+#define _LINUX_KHUGEPAGED_H
+
+#include <linux/sched.h> /* MMF_VM_HUGEPAGE */
+
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+extern int __khugepaged_enter(struct mm_struct *mm);
+extern void __khugepaged_exit(struct mm_struct *mm);
+extern int khugepaged_enter_vma_merge(struct vm_area_struct *vma);
+
+#define khugepaged_enabled()                                           \
+        (transparent_hugepage_flags &                                  \
+         ((1<<TRANSPARENT_HUGEPAGE_FLAG) |                     \
+          (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG)))
+#define khugepaged_always()                             \
+        (transparent_hugepage_flags &                   \
+         (1<<TRANSPARENT_HUGEPAGE_FLAG))
+#define khugepaged_req_madv()                                   \
+        (transparent_hugepage_flags &                           \
+         (1<<TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG))
+#define khugepaged_defrag()                                     \
+        (transparent_hugepage_flags &                           \
+         (1<<TRANSPARENT_HUGEPAGE_DEFRAG_KHUGEPAGED_FLAG))
+
+static inline int khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+        if (test_bit(MMF_VM_HUGEPAGE, &oldmm->flags))
+                return __khugepaged_enter(mm);
+        return 0;
+}
+
+static inline void khugepaged_exit(struct mm_struct *mm)
+{
+        if (test_bit(MMF_VM_HUGEPAGE, &mm->flags))
+                __khugepaged_exit(mm);
+}
+
+static inline int khugepaged_enter(struct vm_area_struct *vma)
+{
+        if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags))
+                if (khugepaged_always() ||
+                    (khugepaged_req_madv() &&
+                     vma->vm_flags & VM_HUGEPAGE))
+                        if (__khugepaged_enter(vma->vm_mm))
+                                return -ENOMEM;
+        return 0;
+}
+#else /* CONFIG_TRANSPARENT_HUGEPAGE */
+static inline int khugepaged_fork(struct mm_struct *mm, struct mm_struct *oldmm)
+{
+        return 0;
+}
+static inline void khugepaged_exit(struct mm_struct *mm)
+{
+}
+static inline int khugepaged_enter(struct vm_area_struct *vma)
+{
+        return 0;
+}
+static inline int khugepaged_enter_vma_merge(struct vm_area_struct *vma)
+{
+        return 0;
+}
+#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
+
+#endif /* _LINUX_KHUGEPAGED_H */
diff --git a/include/linux/sched.h b/include/linux/sched.h
index f23b5bb6f52..d747f948b34 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -434,6 +434,7 @@ extern int get_dumpable(struct mm_struct *mm);
 #endif
                                         /* leave room for more dump flags */
 #define MMF_VM_MERGEABLE        16      /* KSM may merge identical pages */
+#define MMF_VM_HUGEPAGE         17      /* set when VM_HUGEPAGE is set on vma */
 
 #define MMF_INIT_MASK           (MMF_DUMPABLE_MASK | MMF_DUMP_FILTER_MASK)