1 files changed, 175 insertions, 16 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 216d024f830d..bb83c0da2071 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -25,7 +25,20 @@
  * pointing to this anon_vma once its vma list is empty.
  */
 struct anon_vma {
+	struct anon_vma *root;	/* Root of this anon_vma tree */
 	spinlock_t lock;	/* Serialize access to vma list */
+#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
+
+	/*
+	 * The external_refcount is taken by either KSM or page migration
+	 * to take a reference to an anon_vma when there is no
+	 * guarantee that the vma of page tables will exist for
+	 * the duration of the operation. A caller that takes
+	 * the reference is responsible for clearing up the
+	 * anon_vma if they are the last user on release
+	 */
+	atomic_t external_refcount;
+#endif
 	/*
 	 * NOTE: the LSB of the head.next is set by
 	 * mm_take_all_locks() _after_ taking the above lock. So the
@@ -34,23 +47,96 @@ struct anon_vma {
 	 * is serialized by a system wide lock only visible to
 	 * mm_take_all_locks() (mm_all_locks_mutex).
 	 */
-	struct list_head head;	/* List of private "related" vmas */
+	struct list_head head;	/* Chain of private "related" vmas */
+};
+
+/*
+ * The copy-on-write semantics of fork mean that an anon_vma
+ * can become associated with multiple processes. Furthermore,
+ * each child process will have its own anon_vma, where new
+ * pages for that process are instantiated.
+ *
+ * This structure allows us to find the anon_vmas associated
+ * with a VMA, or the VMAs associated with an anon_vma.
+ * The "same_vma" list contains the anon_vma_chains linking
+ * all the anon_vmas associated with this VMA.
+ * The "same_anon_vma" list contains the anon_vma_chains
+ * which link all the VMAs associated with this anon_vma.
+ */
+struct anon_vma_chain {
+	struct vm_area_struct *vma;
+	struct anon_vma *anon_vma;
+	struct list_head same_vma;   /* locked by mmap_sem & page_table_lock */
+	struct list_head same_anon_vma;	/* locked by anon_vma->lock */
 };
 
 #ifdef CONFIG_MMU
+#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
+static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
+{
+	atomic_set(&anon_vma->external_refcount, 0);
+}
+
+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)
+{
+}
+
+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 anon_vma_lock(struct vm_area_struct *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)
+{
+	if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
+					    PAGE_MAPPING_ANON)
+		return NULL;
+	return page_rmapping(page);
+}
+
+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);
 }
 
 /*
@@ -58,41 +144,81 @@ static inline void anon_vma_unlock(struct vm_area_struct *vma)
  */
 void anon_vma_init(void);	/* create anon_vma_cachep */
 int  anon_vma_prepare(struct vm_area_struct *);
-void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);
-void anon_vma_unlink(struct vm_area_struct *);
-void anon_vma_link(struct vm_area_struct *);
+void unlink_anon_vmas(struct vm_area_struct *);
+int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
+int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);
 void __anon_vma_link(struct vm_area_struct *);
+void anon_vma_free(struct anon_vma *);
+
+static inline void anon_vma_merge(struct vm_area_struct *vma,
+				  struct vm_area_struct *next)
+{
+	VM_BUG_ON(vma->anon_vma != next->anon_vma);
+	unlink_anon_vmas(next);
+}
 
 /*
  * rmap interfaces called when adding or removing pte of page
  */
+void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
+void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
+			   unsigned long, int);
 void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_file_rmap(struct page *);
 void page_remove_rmap(struct page *);
 
-#ifdef CONFIG_DEBUG_VM
-void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);
-#else
-static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)
+void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
+			    unsigned long);
+void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
+				unsigned long);
+
+static inline void page_dup_rmap(struct page *page)
 {
 	atomic_inc(&page->_mapcount);
 }
-#endif
 
 /*
  * Called from mm/vmscan.c to handle paging out
  */
 int page_referenced(struct page *, int is_locked,
 			struct mem_cgroup *cnt, unsigned long *vm_flags);
-int try_to_unmap(struct page *, int ignore_refs);
+int page_referenced_one(struct page *, struct vm_area_struct *,
+	unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
+
+enum ttu_flags {
+	TTU_UNMAP = 0,			/* unmap mode */
+	TTU_MIGRATION = 1,		/* migration mode */
+	TTU_MUNLOCK = 2,		/* munlock mode */
+	TTU_ACTION_MASK = 0xff,
+
+	TTU_IGNORE_MLOCK = (1 << 8),	/* ignore mlock */
+	TTU_IGNORE_ACCESS = (1 << 9),	/* don't age */
+	TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
+};
+#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
+
+int try_to_unmap(struct page *, enum ttu_flags flags);
+int try_to_unmap_one(struct page *, struct vm_area_struct *,
+			unsigned long address, enum ttu_flags flags);
 
 /*
  * Called from mm/filemap_xip.c to unmap empty zero page
  */
-pte_t *page_check_address(struct page *, struct mm_struct *,
+pte_t *__page_check_address(struct page *, struct mm_struct *,
 				unsigned long, spinlock_t **, int);
 
+static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm,
+					unsigned long address,
+					spinlock_t **ptlp, int sync)
+{
+	pte_t *ptep;
+
+	__cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
+						       ptlp, sync));
+	return ptep;
+}
+
 /*
  * Used by swapoff to help locate where page is expected in vma.
  */
@@ -112,13 +238,46 @@ int page_mkclean(struct page *);
  */
 int try_to_munlock(struct page *);
 
+/*
+ * Called by memory-failure.c to kill processes.
+ */
+struct anon_vma *__page_lock_anon_vma(struct page *page);
+
+static inline struct anon_vma *page_lock_anon_vma(struct page *page)
+{
+	struct anon_vma *anon_vma;
+
+	__cond_lock(RCU, anon_vma = __page_lock_anon_vma(page));
+
+	/* (void) is needed to make gcc happy */
+	(void) __cond_lock(&anon_vma->root->lock, anon_vma);
+
+	return anon_vma;
+}
+
+void page_unlock_anon_vma(struct anon_vma *anon_vma);
+int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
+
+/*
+ * Called by migrate.c to remove migration ptes, but might be used more later.
+ */
+int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
+		struct vm_area_struct *, unsigned long, void *), void *arg);
+
 #else	/* !CONFIG_MMU */
 
 #define anon_vma_init()		do {} while (0)
 #define anon_vma_prepare(vma)	(0)
 #define anon_vma_link(vma)	do {} while (0)
 
-#define page_referenced(page, locked, cnt, flags) TestClearPageReferenced(page)
+static inline int page_referenced(struct page *page, int is_locked,
+				  struct mem_cgroup *cnt,
+				  unsigned long *vm_flags)
+{
+	*vm_flags = 0;
+	return 0;
+}
+
 #define try_to_unmap(page, refs) SWAP_FAIL
 
 static inline int page_mkclean(struct page *page)