1 files changed, 346 insertions, 177 deletions

diff --git a/mm/rmap.c b/mm/rmap.c
index 92e6757f196e..23295f65ae43 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -24,22 +24,22 @@
  *   inode->i_alloc_sem (vmtruncate_range)
  *   mm->mmap_sem
  *     page->flags PG_locked (lock_page)
- *       mapping->i_mmap_lock
- *         anon_vma->lock
+ *       mapping->i_mmap_mutex
+ *         anon_vma->mutex
  *           mm->page_table_lock or pte_lock
  *             zone->lru_lock (in mark_page_accessed, isolate_lru_page)
  *             swap_lock (in swap_duplicate, swap_info_get)
  *               mmlist_lock (in mmput, drain_mmlist and others)
  *               mapping->private_lock (in __set_page_dirty_buffers)
- *               inode_lock (in set_page_dirty's __mark_inode_dirty)
+ *               inode->i_lock (in set_page_dirty's __mark_inode_dirty)
+ *               inode_wb_list_lock (in set_page_dirty's __mark_inode_dirty)
  *                 sb_lock (within inode_lock in fs/fs-writeback.c)
  *                 mapping->tree_lock (widely used, in set_page_dirty,
  *                           in arch-dependent flush_dcache_mmap_lock,
- *                           within inode_lock in __sync_single_inode)
+ *                           within inode_wb_list_lock in __sync_single_inode)
  *
- * (code doesn't rely on that order so it could be switched around)
- * ->tasklist_lock
- *   anon_vma->lock      (memory_failure, collect_procs_anon)
+ * anon_vma->mutex,mapping->i_mutex      (memory_failure, collect_procs_anon)
+ *   ->tasklist_lock
  *     pte map lock
  */
 
@@ -67,20 +67,56 @@ static struct kmem_cache *anon_vma_chain_cachep;
 
 static inline struct anon_vma *anon_vma_alloc(void)
 {
-        return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
+        struct anon_vma *anon_vma;
+
+        anon_vma = kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);
+        if (anon_vma) {
+                atomic_set(&anon_vma->refcount, 1);
+                /*
+                 * Initialise the anon_vma root to point to itself. If called
+                 * from fork, the root will be reset to the parents anon_vma.
+                 */
+                anon_vma->root = anon_vma;
+        }
+
+        return anon_vma;
 }
 
-void anon_vma_free(struct anon_vma *anon_vma)
+static inline void anon_vma_free(struct anon_vma *anon_vma)
 {
+        VM_BUG_ON(atomic_read(&anon_vma->refcount));
+
+        /*
+         * Synchronize against page_lock_anon_vma() such that
+         * we can safely hold the lock without the anon_vma getting
+         * freed.
+         *
+         * Relies on the full mb implied by the atomic_dec_and_test() from
+         * put_anon_vma() against the acquire barrier implied by
+         * mutex_trylock() from page_lock_anon_vma(). This orders:
+         *
+         * page_lock_anon_vma()         VS      put_anon_vma()
+         *   mutex_trylock()                      atomic_dec_and_test()
+         *   LOCK                                 MB
+         *   atomic_read()                        mutex_is_locked()
+         *
+         * LOCK should suffice since the actual taking of the lock must
+         * happen _before_ what follows.
+         */
+        if (mutex_is_locked(&anon_vma->root->mutex)) {
+                anon_vma_lock(anon_vma);
+                anon_vma_unlock(anon_vma);
+        }
+
         kmem_cache_free(anon_vma_cachep, anon_vma);
 }
 
-static inline struct anon_vma_chain *anon_vma_chain_alloc(void)
+static inline struct anon_vma_chain *anon_vma_chain_alloc(gfp_t gfp)
 {
-        return kmem_cache_alloc(anon_vma_chain_cachep, GFP_KERNEL);
+        return kmem_cache_alloc(anon_vma_chain_cachep, gfp);
 }
 
-void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
+static void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
 {
         kmem_cache_free(anon_vma_chain_cachep, anon_vma_chain);
 }
@@ -94,7 +130,7 @@ void anon_vma_chain_free(struct anon_vma_chain *anon_vma_chain)
  * anonymous pages mapped into it with that anon_vma.
  *
  * The common case will be that we already have one, but if
- * if not we either need to find an adjacent mapping that we
+ * not we either need to find an adjacent mapping that we
  * can re-use the anon_vma from (very common when the only
  * reason for splitting a vma has been mprotect()), or we
  * allocate a new one.
@@ -122,7 +158,7 @@ int anon_vma_prepare(struct vm_area_struct *vma)
                 struct mm_struct *mm = vma->vm_mm;
                 struct anon_vma *allocated;
 
-                avc = anon_vma_chain_alloc();
+                avc = anon_vma_chain_alloc(GFP_KERNEL);
                 if (!avc)
                         goto out_enomem;
 
@@ -133,11 +169,6 @@ int anon_vma_prepare(struct vm_area_struct *vma)
                         if (unlikely(!anon_vma))
                                 goto out_enomem_free_avc;
                         allocated = anon_vma;
-                        /*
-                         * This VMA had no anon_vma yet.  This anon_vma is
-                         * the root of any anon_vma tree that might form.
-                         */
-                        anon_vma->root = anon_vma;
                 }
 
                 anon_vma_lock(anon_vma);
@@ -156,7 +187,7 @@ int anon_vma_prepare(struct vm_area_struct *vma)
                 anon_vma_unlock(anon_vma);
 
                 if (unlikely(allocated))
-                        anon_vma_free(allocated);
+                        put_anon_vma(allocated);
                 if (unlikely(avc))
                         anon_vma_chain_free(avc);
         }
@@ -168,6 +199,32 @@ int anon_vma_prepare(struct vm_area_struct *vma)
         return -ENOMEM;
 }
 
+/*
+ * This is a useful helper function for locking the anon_vma root as
+ * we traverse the vma->anon_vma_chain, looping over anon_vma's that
+ * have the same vma.
+ *
+ * Such anon_vma's should have the same root, so you'd expect to see
+ * just a single mutex_lock for the whole traversal.
+ */
+static inline struct anon_vma *lock_anon_vma_root(struct anon_vma *root, struct anon_vma *anon_vma)
+{
+        struct anon_vma *new_root = anon_vma->root;
+        if (new_root != root) {
+                if (WARN_ON_ONCE(root))
+                        mutex_unlock(&root->mutex);
+                root = new_root;
+                mutex_lock(&root->mutex);
+        }
+        return root;
+}
+
+static inline void unlock_anon_vma_root(struct anon_vma *root)
+{
+        if (root)
+                mutex_unlock(&root->mutex);
+}
+
 static void anon_vma_chain_link(struct vm_area_struct *vma,
                                 struct anon_vma_chain *avc,
                                 struct anon_vma *anon_vma)
@@ -176,9 +233,11 @@ static void anon_vma_chain_link(struct vm_area_struct *vma,
         avc->anon_vma = anon_vma;
         list_add(&avc->same_vma, &vma->anon_vma_chain);
 
-        anon_vma_lock(anon_vma);
+        /*
+         * It's critical to add new vmas to the tail of the anon_vma,
+         * see comment in huge_memory.c:__split_huge_page().
+         */
         list_add_tail(&avc->same_anon_vma, &anon_vma->head);
-        anon_vma_unlock(anon_vma);
 }
 
 /*
@@ -188,13 +247,24 @@ static void anon_vma_chain_link(struct vm_area_struct *vma,
 int anon_vma_clone(struct vm_area_struct *dst, struct vm_area_struct *src)
 {
         struct anon_vma_chain *avc, *pavc;
+        struct anon_vma *root = NULL;
 
         list_for_each_entry_reverse(pavc, &src->anon_vma_chain, same_vma) {
-                avc = anon_vma_chain_alloc();
-                if (!avc)
-                        goto enomem_failure;
-                anon_vma_chain_link(dst, avc, pavc->anon_vma);
+                struct anon_vma *anon_vma;
+
+                avc = anon_vma_chain_alloc(GFP_NOWAIT | __GFP_NOWARN);
+                if (unlikely(!avc)) {
+                        unlock_anon_vma_root(root);
+                        root = NULL;
+                        avc = anon_vma_chain_alloc(GFP_KERNEL);
+                        if (!avc)
+                                goto enomem_failure;
+                }
+                anon_vma = pavc->anon_vma;
+                root = lock_anon_vma_root(root, anon_vma);
+                anon_vma_chain_link(dst, avc, anon_vma);
         }
+        unlock_anon_vma_root(root);
         return 0;
 
  enomem_failure:
@@ -227,7 +297,7 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
         anon_vma = anon_vma_alloc();
         if (!anon_vma)
                 goto out_error;
-        avc = anon_vma_chain_alloc();
+        avc = anon_vma_chain_alloc(GFP_KERNEL);
         if (!avc)
                 goto out_error_free_anon_vma;
 
@@ -237,58 +307,63 @@ int anon_vma_fork(struct vm_area_struct *vma, struct vm_area_struct *pvma)
          */
         anon_vma->root = pvma->anon_vma->root;
         /*
-         * With KSM refcounts, an anon_vma can stay around longer than the
-         * process it belongs to.  The root anon_vma needs to be pinned
-         * until this anon_vma is freed, because the lock lives in the root.
+         * With refcounts, an anon_vma can stay around longer than the
+         * process it belongs to. The root anon_vma needs to be pinned until
+         * this anon_vma is freed, because the lock lives in the root.
          */
         get_anon_vma(anon_vma->root);
         /* Mark this anon_vma as the one where our new (COWed) pages go. */
         vma->anon_vma = anon_vma;
+        anon_vma_lock(anon_vma);
         anon_vma_chain_link(vma, avc, anon_vma);
+        anon_vma_unlock(anon_vma);
 
         return 0;
 
  out_error_free_anon_vma:
-        anon_vma_free(anon_vma);
+        put_anon_vma(anon_vma);
  out_error:
         unlink_anon_vmas(vma);
         return -ENOMEM;
 }
 
-static void anon_vma_unlink(struct anon_vma_chain *anon_vma_chain)
+void unlink_anon_vmas(struct vm_area_struct *vma)
 {
-        struct anon_vma *anon_vma = anon_vma_chain->anon_vma;
-        int empty;
+        struct anon_vma_chain *avc, *next;
+        struct anon_vma *root = NULL;
 
-        /* If anon_vma_fork fails, we can get an empty anon_vma_chain. */
-        if (!anon_vma)
-                return;
+        /*
+         * Unlink each anon_vma chained to the VMA.  This list is ordered
+         * from newest to oldest, ensuring the root anon_vma gets freed last.
+         */
+        list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
+                struct anon_vma *anon_vma = avc->anon_vma;
 
-        anon_vma_lock(anon_vma);
-        list_del(&anon_vma_chain->same_anon_vma);
+                root = lock_anon_vma_root(root, anon_vma);
+                list_del(&avc->same_anon_vma);
 
-        /* We must garbage collect the anon_vma if it's empty */
-        empty = list_empty(&anon_vma->head) && !anonvma_external_refcount(anon_vma);
-        anon_vma_unlock(anon_vma);
+                /*
+                 * Leave empty anon_vmas on the list - we'll need
+                 * to free them outside the lock.
+                 */
+                if (list_empty(&anon_vma->head))
+                        continue;
 
-        if (empty) {
-                /* We no longer need the root anon_vma */
-                if (anon_vma->root != anon_vma)
-                        drop_anon_vma(anon_vma->root);
-                anon_vma_free(anon_vma);
+                list_del(&avc->same_vma);
+                anon_vma_chain_free(avc);
         }
-}
-
-void unlink_anon_vmas(struct vm_area_struct *vma)
-{
-        struct anon_vma_chain *avc, *next;
+        unlock_anon_vma_root(root);
 
         /*
-         * Unlink each anon_vma chained to the VMA.  This list is ordered
-         * from newest to oldest, ensuring the root anon_vma gets freed last.
+         * Iterate the list once more, it now only contains empty and unlinked
+         * anon_vmas, destroy them. Could not do before due to __put_anon_vma()
+         * needing to acquire the anon_vma->root->mutex.
          */
         list_for_each_entry_safe(avc, next, &vma->anon_vma_chain, same_vma) {
-                anon_vma_unlink(avc);
+                struct anon_vma *anon_vma = avc->anon_vma;
+
+                put_anon_vma(anon_vma);
+
                 list_del(&avc->same_vma);
                 anon_vma_chain_free(avc);
         }
@@ -298,8 +373,8 @@ static void anon_vma_ctor(void *data)
 {
         struct anon_vma *anon_vma = data;
 
-        spin_lock_init(&anon_vma->lock);
-        anonvma_external_refcount_init(anon_vma);
+        mutex_init(&anon_vma->mutex);
+        atomic_set(&anon_vma->refcount, 0);
         INIT_LIST_HEAD(&anon_vma->head);
 }
 
@@ -311,12 +386,31 @@ void __init anon_vma_init(void)
 }
 
 /*
- * Getting a lock on a stable anon_vma from a page off the LRU is
- * tricky: page_lock_anon_vma rely on RCU to guard against the races.
+ * Getting a lock on a stable anon_vma from a page off the LRU is tricky!
+ *
+ * Since there is no serialization what so ever against page_remove_rmap()
+ * the best this function can do is return a locked anon_vma that might
+ * have been relevant to this page.
+ *
+ * The page might have been remapped to a different anon_vma or the anon_vma
+ * returned may already be freed (and even reused).
+ *
+ * In case it was remapped to a different anon_vma, the new anon_vma will be a
+ * child of the old anon_vma, and the anon_vma lifetime rules will therefore
+ * ensure that any anon_vma obtained from the page will still be valid for as
+ * long as we observe page_mapped() [ hence all those page_mapped() tests ].
+ *
+ * All users of this function must be very careful when walking the anon_vma
+ * chain and verify that the page in question is indeed mapped in it
+ * [ something equivalent to page_mapped_in_vma() ].
+ *
+ * Since anon_vma's slab is DESTROY_BY_RCU and we know from page_remove_rmap()
+ * that the anon_vma pointer from page->mapping is valid if there is a
+ * mapcount, we can dereference the anon_vma after observing those.
  */
-struct anon_vma *page_lock_anon_vma(struct page *page)
+struct anon_vma *page_get_anon_vma(struct page *page)
 {
-        struct anon_vma *anon_vma, *root_anon_vma;
+        struct anon_vma *anon_vma = NULL;
         unsigned long anon_mapping;
 
         rcu_read_lock();
@@ -327,30 +421,100 @@ struct anon_vma *page_lock_anon_vma(struct page *page)
                 goto out;
 
         anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
-        root_anon_vma = ACCESS_ONCE(anon_vma->root);
-        spin_lock(&root_anon_vma->lock);
+        if (!atomic_inc_not_zero(&anon_vma->refcount)) {
+                anon_vma = NULL;
+                goto out;
+        }
 
         /*
          * If this page is still mapped, then its anon_vma cannot have been
-         * freed.  But if it has been unmapped, we have no security against
-         * the anon_vma structure being freed and reused (for another anon_vma:
-         * SLAB_DESTROY_BY_RCU guarantees that - so the spin_lock above cannot
-         * corrupt): with anon_vma_prepare() or anon_vma_fork() redirecting
-         * anon_vma->root before page_unlock_anon_vma() is called to unlock.
+         * freed.  But if it has been unmapped, we have no security against the
+         * anon_vma structure being freed and reused (for another anon_vma:
+         * SLAB_DESTROY_BY_RCU guarantees that - so the atomic_inc_not_zero()
+         * above cannot corrupt).
          */
-        if (page_mapped(page))
-                return anon_vma;
+        if (!page_mapped(page)) {
+                put_anon_vma(anon_vma);
+                anon_vma = NULL;
+        }
+out:
+        rcu_read_unlock();
+
+        return anon_vma;
+}
+
+/*
+ * Similar to page_get_anon_vma() except it locks the anon_vma.
+ *
+ * Its a little more complex as it tries to keep the fast path to a single
+ * atomic op -- the trylock. If we fail the trylock, we fall back to getting a
+ * reference like with page_get_anon_vma() and then block on the mutex.
+ */
+struct anon_vma *page_lock_anon_vma(struct page *page)
+{
+        struct anon_vma *anon_vma = NULL;
+        struct anon_vma *root_anon_vma;
+        unsigned long anon_mapping;
+
+        rcu_read_lock();
+        anon_mapping = (unsigned long) ACCESS_ONCE(page->mapping);
+        if ((anon_mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
+                goto out;
+        if (!page_mapped(page))
+                goto out;
+
+        anon_vma = (struct anon_vma *) (anon_mapping - PAGE_MAPPING_ANON);
+        root_anon_vma = ACCESS_ONCE(anon_vma->root);
+        if (mutex_trylock(&root_anon_vma->mutex)) {
+                /*
+                 * If the page is still mapped, then this anon_vma is still
+                 * its anon_vma, and holding the mutex ensures that it will
+                 * not go away, see anon_vma_free().
+                 */
+                if (!page_mapped(page)) {
+                        mutex_unlock(&root_anon_vma->mutex);
+                        anon_vma = NULL;
+                }
+                goto out;
+        }
+
+        /* trylock failed, we got to sleep */
+        if (!atomic_inc_not_zero(&anon_vma->refcount)) {
+                anon_vma = NULL;
+                goto out;
+        }
+
+        if (!page_mapped(page)) {
+                put_anon_vma(anon_vma);
+                anon_vma = NULL;
+                goto out;
+        }
+
+        /* we pinned the anon_vma, its safe to sleep */
+        rcu_read_unlock();
+        anon_vma_lock(anon_vma);
+
+        if (atomic_dec_and_test(&anon_vma->refcount)) {
+                /*
+                 * Oops, we held the last refcount, release the lock
+                 * and bail -- can't simply use put_anon_vma() because
+                 * we'll deadlock on the anon_vma_lock() recursion.
+                 */
+                anon_vma_unlock(anon_vma);
+                __put_anon_vma(anon_vma);
+                anon_vma = NULL;
+        }
+
+        return anon_vma;
 
-        spin_unlock(&root_anon_vma->lock);
 out:
         rcu_read_unlock();
-        return NULL;
+        return anon_vma;
 }
 
 void page_unlock_anon_vma(struct anon_vma *anon_vma)
 {
         anon_vma_unlock(anon_vma);
-        rcu_read_unlock();
 }
 
 /*
@@ -358,7 +522,7 @@ void page_unlock_anon_vma(struct anon_vma *anon_vma)
  * Returns virtual address or -EFAULT if page's index/offset is not
  * within the range mapped the @vma.
  */
-static inline unsigned long
+inline unsigned long
 vma_address(struct page *page, struct vm_area_struct *vma)
 {
         pgoff_t pgoff = page->index << (PAGE_CACHE_SHIFT - PAGE_SHIFT);
@@ -407,7 +571,7 @@ unsigned long page_address_in_vma(struct page *page, struct vm_area_struct *vma)
  *
  * On success returns with pte mapped and locked.
  */
-pte_t *page_check_address(struct page *page, struct mm_struct *mm,
+pte_t *__page_check_address(struct page *page, struct mm_struct *mm,
                           unsigned long address, spinlock_t **ptlp, int sync)
 {
         pgd_t *pgd;
@@ -433,6 +597,8 @@ pte_t *page_check_address(struct page *page, struct mm_struct *mm,
         pmd = pmd_offset(pud, address);
         if (!pmd_present(*pmd))
                 return NULL;
+        if (pmd_trans_huge(*pmd))
+                return NULL;
 
         pte = pte_offset_map(pmd, address);
         /* Make a quick check before getting the lock */
@@ -487,35 +653,65 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
                         unsigned long *vm_flags)
 {
         struct mm_struct *mm = vma->vm_mm;
-        pte_t *pte;
-        spinlock_t *ptl;
         int referenced = 0;
 
-        pte = page_check_address(page, mm, address, &ptl, 0);
-        if (!pte)
-                goto out;
-
-        /*
-         * Don't want to elevate referenced for mlocked page that gets this far,
-         * in order that it progresses to try_to_unmap and is moved to the
-         * unevictable list.
-         */
-        if (vma->vm_flags & VM_LOCKED) {
-                *mapcount = 1;  /* break early from loop */
-                *vm_flags |= VM_LOCKED;
-                goto out_unmap;
-        }
+        if (unlikely(PageTransHuge(page))) {
+                pmd_t *pmd;
 
-        if (ptep_clear_flush_young_notify(vma, address, pte)) {
+                spin_lock(&mm->page_table_lock);
                 /*
-                 * Don't treat a reference through a sequentially read
-                 * mapping as such.  If the page has been used in
-                 * another mapping, we will catch it; if this other
-                 * mapping is already gone, the unmap path will have
-                 * set PG_referenced or activated the page.
+                 * rmap might return false positives; we must filter
+                 * these out using page_check_address_pmd().
                  */
-                if (likely(!VM_SequentialReadHint(vma)))
+                pmd = page_check_address_pmd(page, mm, address,
+                                             PAGE_CHECK_ADDRESS_PMD_FLAG);
+                if (!pmd) {
+                        spin_unlock(&mm->page_table_lock);
+                        goto out;
+                }
+
+                if (vma->vm_flags & VM_LOCKED) {
+                        spin_unlock(&mm->page_table_lock);
+                        *mapcount = 0;  /* break early from loop */
+                        *vm_flags |= VM_LOCKED;
+                        goto out;
+                }
+
+                /* go ahead even if the pmd is pmd_trans_splitting() */
+                if (pmdp_clear_flush_young_notify(vma, address, pmd))
                         referenced++;
+                spin_unlock(&mm->page_table_lock);
+        } else {
+                pte_t *pte;
+                spinlock_t *ptl;
+
+                /*
+                 * rmap might return false positives; we must filter
+                 * these out using page_check_address().
+                 */
+                pte = page_check_address(page, mm, address, &ptl, 0);
+                if (!pte)
+                        goto out;
+
+                if (vma->vm_flags & VM_LOCKED) {
+                        pte_unmap_unlock(pte, ptl);
+                        *mapcount = 0;  /* break early from loop */
+                        *vm_flags |= VM_LOCKED;
+                        goto out;
+                }
+
+                if (ptep_clear_flush_young_notify(vma, address, pte)) {
+                        /*
+                         * Don't treat a reference through a sequentially read
+                         * mapping as such.  If the page has been used in
+                         * another mapping, we will catch it; if this other
+                         * mapping is already gone, the unmap path will have
+                         * set PG_referenced or activated the page.
+                         */
+                        if (likely(!VM_SequentialReadHint(vma)))
+                                referenced++;
+                }
+                pte_unmap_unlock(pte, ptl);
         }
 
         /* Pretend the page is referenced if the task has the
@@ -524,9 +720,7 @@ int page_referenced_one(struct page *page, struct vm_area_struct *vma,
                         rwsem_is_locked(&mm->mmap_sem))
                 referenced++;
 
-out_unmap:
         (*mapcount)--;
-        pte_unmap_unlock(pte, ptl);
 
         if (referenced)
                 *vm_flags |= vma->vm_flags;
@@ -605,14 +799,14 @@ static int page_referenced_file(struct page *page,
          * The page lock not only makes sure that page->mapping cannot
          * suddenly be NULLified by truncation, it makes sure that the
          * structure at mapping cannot be freed and reused yet,
-         * so we can safely take mapping->i_mmap_lock.
+         * so we can safely take mapping->i_mmap_mutex.
          */
         BUG_ON(!PageLocked(page));
 
-        spin_lock(&mapping->i_mmap_lock);
+        mutex_lock(&mapping->i_mmap_mutex);
 
         /*
-         * i_mmap_lock does not stabilize mapcount at all, but mapcount
+         * i_mmap_mutex does not stabilize mapcount at all, but mapcount
          * is more likely to be accurate if we note it after spinning.
          */
         mapcount = page_mapcount(page);
@@ -634,7 +828,7 @@ static int page_referenced_file(struct page *page,
                         break;
         }
 
-        spin_unlock(&mapping->i_mmap_lock);
+        mutex_unlock(&mapping->i_mmap_mutex);
         return referenced;
 }
 
@@ -678,7 +872,7 @@ int page_referenced(struct page *page,
                         unlock_page(page);
         }
 out:
-        if (page_test_and_clear_young(page))
+        if (page_test_and_clear_young(page_to_pfn(page)))
                 referenced++;
 
         return referenced;
@@ -721,7 +915,7 @@ static int page_mkclean_file(struct address_space *mapping, struct page *page)
 
         BUG_ON(PageAnon(page));
 
-        spin_lock(&mapping->i_mmap_lock);
+        mutex_lock(&mapping->i_mmap_mutex);
         vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
                 if (vma->vm_flags & VM_SHARED) {
                         unsigned long address = vma_address(page, vma);
@@ -730,7 +924,7 @@ static int page_mkclean_file(struct address_space *mapping, struct page *page)
                         ret += page_mkclean_one(page, vma, address);
                 }
         }
-        spin_unlock(&mapping->i_mmap_lock);
+        mutex_unlock(&mapping->i_mmap_mutex);
         return ret;
 }
 
@@ -744,10 +938,8 @@ int page_mkclean(struct page *page)
                 struct address_space *mapping = page_mapping(page);
                 if (mapping) {
                         ret = page_mkclean_file(mapping, page);
-                        if (page_test_dirty(page)) {
-                                page_clear_dirty(page);
+                        if (page_test_and_clear_dirty(page_to_pfn(page), 1))
                                 ret = 1;
-                        }
                 }
         }
 
@@ -780,10 +972,10 @@ void page_move_anon_rmap(struct page *page,
 }
 
 /**
- * __page_set_anon_rmap - setup new anonymous rmap
- * @page:       the page to add the mapping to
- * @vma:        the vm area in which the mapping is added
- * @address:    the user virtual address mapped
+ * __page_set_anon_rmap - set up new anonymous rmap
+ * @page:       Page to add to rmap     
+ * @vma:        VM area to add page to.
+ * @address:    User virtual address of the mapping     
  * @exclusive:  the page is exclusively owned by the current process
  */
 static void __page_set_anon_rmap(struct page *page,
@@ -793,25 +985,16 @@ static void __page_set_anon_rmap(struct page *page,
 
         BUG_ON(!anon_vma);
 
+        if (PageAnon(page))
+                return;
+
         /*
          * If the page isn't exclusively mapped into this vma,
          * we must use the _oldest_ possible anon_vma for the
          * page mapping!
          */
-        if (!exclusive) {
-                if (PageAnon(page))
-                        return;
+        if (!exclusive)
                 anon_vma = anon_vma->root;
-        } else {
-                /*
-                 * In this case, swapped-out-but-not-discarded swap-cache
-                 * is remapped. So, no need to update page->mapping here.
-                 * We convice anon_vma poitned by page->mapping is not obsolete
-                 * because vma->anon_vma is necessary to be a family of it.
-                 */
-                if (PageAnon(page))
-                        return;
-        }
 
         anon_vma = (void *) anon_vma + PAGE_MAPPING_ANON;
         page->mapping = (struct address_space *) anon_vma;
@@ -871,13 +1054,18 @@ void do_page_add_anon_rmap(struct page *page,
         struct vm_area_struct *vma, unsigned long address, int exclusive)
 {
         int first = atomic_inc_and_test(&page->_mapcount);
-        if (first)
-                __inc_zone_page_state(page, NR_ANON_PAGES);
+        if (first) {
+                if (!PageTransHuge(page))
+                        __inc_zone_page_state(page, NR_ANON_PAGES);
+                else
+                        __inc_zone_page_state(page,
+                                              NR_ANON_TRANSPARENT_HUGEPAGES);
+        }
         if (unlikely(PageKsm(page)))
                 return;
 
         VM_BUG_ON(!PageLocked(page));
-        VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+        /* address might be in next vma when migration races vma_adjust */
         if (first)
                 __page_set_anon_rmap(page, vma, address, exclusive);
         else
@@ -900,7 +1088,10 @@ void page_add_new_anon_rmap(struct page *page,
         VM_BUG_ON(address < vma->vm_start || address >= vma->vm_end);
         SetPageSwapBacked(page);
         atomic_set(&page->_mapcount, 0); /* increment count (starts at -1) */
-        __inc_zone_page_state(page, NR_ANON_PAGES);
+        if (!PageTransHuge(page))
+                __inc_zone_page_state(page, NR_ANON_PAGES);
+        else
+                __inc_zone_page_state(page, NR_ANON_TRANSPARENT_HUGEPAGES);
         __page_set_anon_rmap(page, vma, address, 1);
         if (page_evictable(page, vma))
                 lru_cache_add_lru(page, LRU_ACTIVE_ANON);
@@ -918,7 +1109,7 @@ void page_add_file_rmap(struct page *page)
 {
         if (atomic_inc_and_test(&page->_mapcount)) {
                 __inc_zone_page_state(page, NR_FILE_MAPPED);
-                mem_cgroup_update_file_mapped(page, 1);
+                mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
         }
 }
 
@@ -941,10 +1132,9 @@ void page_remove_rmap(struct page *page)
          * not if it's in swapcache - there might be another pte slot
          * containing the swap entry, but page not yet written to swap.
          */
-        if ((!PageAnon(page) || PageSwapCache(page)) && page_test_dirty(page)) {
-                page_clear_dirty(page);
+        if ((!PageAnon(page) || PageSwapCache(page)) &&
+            page_test_and_clear_dirty(page_to_pfn(page), 1))
                 set_page_dirty(page);
-        }
         /*
          * Hugepages are not counted in NR_ANON_PAGES nor NR_FILE_MAPPED
          * and not charged by memcg for now.
@@ -953,10 +1143,14 @@ void page_remove_rmap(struct page *page)
                 return;
         if (PageAnon(page)) {
                 mem_cgroup_uncharge_page(page);
-                __dec_zone_page_state(page, NR_ANON_PAGES);
+                if (!PageTransHuge(page))
+                        __dec_zone_page_state(page, NR_ANON_PAGES);
+                else
+                        __dec_zone_page_state(page,
+                                              NR_ANON_TRANSPARENT_HUGEPAGES);
         } else {
                 __dec_zone_page_state(page, NR_FILE_MAPPED);
-                mem_cgroup_update_file_mapped(page, -1);
+                mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
         }
         /*
          * It would be tidy to reset the PageAnon mapping here,
@@ -1078,7 +1272,7 @@ out_mlock:
         /*
          * We need mmap_sem locking, Otherwise VM_LOCKED check makes
          * unstable result and race. Plus, We can't wait here because
-         * we now hold anon_vma->lock or mapping->i_mmap_lock.
+         * we now hold anon_vma->mutex or mapping->i_mmap_mutex.
          * if trylock failed, the page remain in evictable lru and later
          * vmscan could retry to move the page to unevictable lru if the
          * page is actually mlocked.
@@ -1209,7 +1403,7 @@ static int try_to_unmap_cluster(unsigned long cursor, unsigned int *mapcount,
         return ret;
 }
 
-static bool is_vma_temporary_stack(struct vm_area_struct *vma)
+bool is_vma_temporary_stack(struct vm_area_struct *vma)
 {
         int maybe_stack = vma->vm_flags & (VM_GROWSDOWN | VM_GROWSUP);
 
@@ -1304,7 +1498,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
         unsigned long max_nl_size = 0;
         unsigned int mapcount;
 
-        spin_lock(&mapping->i_mmap_lock);
+        mutex_lock(&mapping->i_mmap_mutex);
         vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
                 unsigned long address = vma_address(page, vma);
                 if (address == -EFAULT)
@@ -1350,7 +1544,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
         mapcount = page_mapcount(page);
         if (!mapcount)
                 goto out;
-        cond_resched_lock(&mapping->i_mmap_lock);
+        cond_resched();
 
         max_nl_size = (max_nl_size + CLUSTER_SIZE - 1) & CLUSTER_MASK;
         if (max_nl_cursor == 0)
@@ -1372,7 +1566,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
                         }
                         vma->vm_private_data = (void *) max_nl_cursor;
                 }
-                cond_resched_lock(&mapping->i_mmap_lock);
+                cond_resched();
                 max_nl_cursor += CLUSTER_SIZE;
         } while (max_nl_cursor <= max_nl_size);
 
@@ -1384,7 +1578,7 @@ static int try_to_unmap_file(struct page *page, enum ttu_flags flags)
         list_for_each_entry(vma, &mapping->i_mmap_nonlinear, shared.vm_set.list)
                 vma->vm_private_data = NULL;
 out:
-        spin_unlock(&mapping->i_mmap_lock);
+        mutex_unlock(&mapping->i_mmap_mutex);
         return ret;
 }
 
@@ -1407,6 +1601,7 @@ int try_to_unmap(struct page *page, enum ttu_flags flags)
         int ret;
 
         BUG_ON(!PageLocked(page));
+        VM_BUG_ON(!PageHuge(page) && PageTransHuge(page));
 
         if (unlikely(PageKsm(page)))
                 ret = try_to_unmap_ksm(page, flags);
@@ -1446,41 +1641,15 @@ int try_to_munlock(struct page *page)
                 return try_to_unmap_file(page, TTU_MUNLOCK);
 }
 
-#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
-/*
- * Drop an anon_vma refcount, freeing the anon_vma and anon_vma->root
- * if necessary.  Be careful to do all the tests under the lock.  Once
- * we know we are the last user, nobody else can get a reference and we
- * can do the freeing without the lock.
- */
-void drop_anon_vma(struct anon_vma *anon_vma)
+void __put_anon_vma(struct anon_vma *anon_vma)
 {
-        BUG_ON(atomic_read(&anon_vma->external_refcount) <= 0);
-        if (atomic_dec_and_lock(&anon_vma->external_refcount, &anon_vma->root->lock)) {
-                struct anon_vma *root = anon_vma->root;
-                int empty = list_empty(&anon_vma->head);
-                int last_root_user = 0;
-                int root_empty = 0;
+        struct anon_vma *root = anon_vma->root;
 
-                /*
-                 * The refcount on a non-root anon_vma got dropped.  Drop
-                 * the refcount on the root and check if we need to free it.
-                 */
-                if (empty && anon_vma != root) {
-                        BUG_ON(atomic_read(&root->external_refcount) <= 0);
-                        last_root_user = atomic_dec_and_test(&root->external_refcount);
-                        root_empty = list_empty(&root->head);
-                }
-                anon_vma_unlock(anon_vma);
+        if (root != anon_vma && atomic_dec_and_test(&root->refcount))
+                anon_vma_free(root);
 
-                if (empty) {
-                        anon_vma_free(anon_vma);
-                        if (root_empty && last_root_user)
-                                anon_vma_free(root);
-                }
-        }
+        anon_vma_free(anon_vma);
 }
-#endif
 
 #ifdef CONFIG_MIGRATION
 /*
@@ -1528,7 +1697,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
 
         if (!mapping)
                 return ret;
-        spin_lock(&mapping->i_mmap_lock);
+        mutex_lock(&mapping->i_mmap_mutex);
         vma_prio_tree_foreach(vma, &iter, &mapping->i_mmap, pgoff, pgoff) {
                 unsigned long address = vma_address(page, vma);
                 if (address == -EFAULT)
@@ -1542,7 +1711,7 @@ static int rmap_walk_file(struct page *page, int (*rmap_one)(struct page *,
          * never contain migration ptes.  Decide what to do about this
          * limitation to linear when we need rmap_walk() on nonlinear.
          */
-        spin_unlock(&mapping->i_mmap_lock);
+        mutex_unlock(&mapping->i_mmap_mutex);
         return ret;
 }
 
@@ -1591,7 +1760,7 @@ void hugepage_add_anon_rmap(struct page *page,
 
         BUG_ON(!PageLocked(page));
         BUG_ON(!anon_vma);
-        BUG_ON(address < vma->vm_start || address >= vma->vm_end);
+        /* address might be in next vma when migration races vma_adjust */
         first = atomic_inc_and_test(&page->_mapcount);
         if (first)
                 __hugepage_set_anon_rmap(page, vma, address, 0);