mm: extend KSM refcounts to the anon_vma root

[sfrench/cifs-2.6.git] / include / linux / rmap.h

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 77216742c178013b9444884b4f4dd05d337a4620..dc9b3c0bf5d46131c7acc0fef179cfce5c7d49c9 100644 (file)
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -26,6 +26,7 @@
  */
 struct anon_vma {
        spinlock_t lock;        /* Serialize access to vma list */
+       struct anon_vma *root;  /* Root of this anon_vma tree */
 #if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
 
        /*
@@ -80,6 +81,13 @@ static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
 {
        return atomic_read(&anon_vma->external_refcount);
 }
+
+static inline void get_anon_vma(struct anon_vma *anon_vma)
+{
+       atomic_inc(&anon_vma->external_refcount);
+}
+
+void drop_anon_vma(struct anon_vma *);
 #else
 static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
 {
@@ -89,6 +97,14 @@ static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
 {
        return 0;
 }
+
+static inline void get_anon_vma(struct anon_vma *anon_vma)
+{
+}
+
+static inline void drop_anon_vma(struct anon_vma *anon_vma)
+{
+}
 #endif /* CONFIG_KSM */
 
 static inline struct anon_vma *page_anon_vma(struct page *page)
@@ -99,18 +115,28 @@ static inline struct anon_vma *page_anon_vma(struct page *page)
        return page_rmapping(page);
 }
 
-static inline void anon_vma_lock(struct vm_area_struct *vma)
+static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
 {
        struct anon_vma *anon_vma = vma->anon_vma;
        if (anon_vma)
-               spin_lock(&anon_vma->lock);
+               spin_lock(&anon_vma->root->lock);
 }
 
-static inline void anon_vma_unlock(struct vm_area_struct *vma)
+static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
 {
        struct anon_vma *anon_vma = vma->anon_vma;
        if (anon_vma)
-               spin_unlock(&anon_vma->lock);
+               spin_unlock(&anon_vma->root->lock);
+}
+
+static inline void anon_vma_lock(struct anon_vma *anon_vma)
+{
+       spin_lock(&anon_vma->root->lock);
+}
+
+static inline void anon_vma_unlock(struct anon_vma *anon_vma)
+{
+       spin_unlock(&anon_vma->root->lock);
 }
 
 /*