mm/list_lru.c - linux-imx - Git at Google

 /*
  * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
  * Authors: David Chinner and Glauber Costa
  *
  * Generic LRU infrastructure
  */
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/mm.h>
 #include <linux/list_lru.h>
 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/memcontrol.h>

 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 static LIST_HEAD(list_lrus);
 static DEFINE_MUTEX(list_lrus_mutex);

 static void list_lru_register(struct list_lru *lru)
 {
 	mutex_lock(&list_lrus_mutex);
 	list_add(&lru->list, &list_lrus);
 	mutex_unlock(&list_lrus_mutex);
 }

 static void list_lru_unregister(struct list_lru *lru)
 {
 	mutex_lock(&list_lrus_mutex);
 	list_del(&lru->list);
 	mutex_unlock(&list_lrus_mutex);
 }
 #else
 static void list_lru_register(struct list_lru *lru)
 {
 }

 static void list_lru_unregister(struct list_lru *lru)
 {
 }
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */

 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
 {
 	/*
 	 * This needs node 0 to be always present, even
 	 * in the systems supporting sparse numa ids.
 	 */
 	return !!lru->node[0].memcg_lrus;
 }

 static inline struct list_lru_one *
 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
 {
 	/*
 	 * The lock protects the array of per cgroup lists from relocation
 	 * (see memcg_update_list_lru_node).
 	 */
 	lockdep_assert_held(&nlru->lock);
 	if (nlru->memcg_lrus && idx >= 0)
 		return nlru->memcg_lrus->lru[idx];

 	return &nlru->lru;
 }

 static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
 {
 	struct page *page;

 	if (!memcg_kmem_enabled())
 		return NULL;
 	page = virt_to_head_page(ptr);
 	return page->mem_cgroup;
 }

 static inline struct list_lru_one *
 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
 {
 	struct mem_cgroup *memcg;

 	if (!nlru->memcg_lrus)
 		return &nlru->lru;

 	memcg = mem_cgroup_from_kmem(ptr);
 	if (!memcg)
 		return &nlru->lru;

 	return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
 }
 #else
 static inline bool list_lru_memcg_aware(struct list_lru *lru)
 {
 	return false;
 }

 static inline struct list_lru_one *
 list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
 {
 	return &nlru->lru;
 }

 static inline struct list_lru_one *
 list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
 {
 	return &nlru->lru;
 }
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */

 bool list_lru_add(struct list_lru *lru, struct list_head *item)
 {
 	int nid = page_to_nid(virt_to_page(item));
 	struct list_lru_node *nlru = &lru->node[nid];
 	struct list_lru_one *l;

 	spin_lock(&nlru->lock);
 	if (list_empty(item)) {
 		l = list_lru_from_kmem(nlru, item);
 		list_add_tail(item, &l->list);
 		l->nr_items++;
 		spin_unlock(&nlru->lock);
 		return true;
 	}
 	spin_unlock(&nlru->lock);
 	return false;
 }
 EXPORT_SYMBOL_GPL(list_lru_add);

 bool list_lru_del(struct list_lru *lru, struct list_head *item)
 {
 	int nid = page_to_nid(virt_to_page(item));
 	struct list_lru_node *nlru = &lru->node[nid];
 	struct list_lru_one *l;

 	spin_lock(&nlru->lock);
 	if (!list_empty(item)) {
 		l = list_lru_from_kmem(nlru, item);
 		list_del_init(item);
 		l->nr_items--;
 		spin_unlock(&nlru->lock);
 		return true;
 	}
 	spin_unlock(&nlru->lock);
 	return false;
 }
 EXPORT_SYMBOL_GPL(list_lru_del);

 void list_lru_isolate(struct list_lru_one *list, struct list_head *item)
 {
 	list_del_init(item);
 	list->nr_items--;
 }
 EXPORT_SYMBOL_GPL(list_lru_isolate);

 void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item,
 			   struct list_head *head)
 {
 	list_move(item, head);
 	list->nr_items--;
 }
 EXPORT_SYMBOL_GPL(list_lru_isolate_move);

 static unsigned long __list_lru_count_one(struct list_lru *lru,
 					  int nid, int memcg_idx)
 {
 	struct list_lru_node *nlru = &lru->node[nid];
 	struct list_lru_one *l;
 	unsigned long count;

 	spin_lock(&nlru->lock);
 	l = list_lru_from_memcg_idx(nlru, memcg_idx);
 	count = l->nr_items;
 	spin_unlock(&nlru->lock);

 	return count;
 }

 unsigned long list_lru_count_one(struct list_lru *lru,
 				 int nid, struct mem_cgroup *memcg)
 {
 	return __list_lru_count_one(lru, nid, memcg_cache_id(memcg));
 }
 EXPORT_SYMBOL_GPL(list_lru_count_one);

 unsigned long list_lru_count_node(struct list_lru *lru, int nid)
 {
 	long count = 0;
 	int memcg_idx;

 	count += __list_lru_count_one(lru, nid, -1);
 	if (list_lru_memcg_aware(lru)) {
 		for_each_memcg_cache_index(memcg_idx)
 			count += __list_lru_count_one(lru, nid, memcg_idx);
 	}
 	return count;
 }
 EXPORT_SYMBOL_GPL(list_lru_count_node);

 static unsigned long
 __list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
 		    list_lru_walk_cb isolate, void *cb_arg,
 		    unsigned long *nr_to_walk)
 {

 	struct list_lru_node *nlru = &lru->node[nid];
 	struct list_lru_one *l;
 	struct list_head *item, *n;
 	unsigned long isolated = 0;

 	spin_lock(&nlru->lock);
 	l = list_lru_from_memcg_idx(nlru, memcg_idx);
 restart:
 	list_for_each_safe(item, n, &l->list) {
 		enum lru_status ret;

 		/*
 		 * decrement nr_to_walk first so that we don't livelock if we
 		 * get stuck on large numbesr of LRU_RETRY items
 		 */
 		if (!*nr_to_walk)
 			break;
 		--*nr_to_walk;

 		ret = isolate(item, l, &nlru->lock, cb_arg);
 		switch (ret) {
 		case LRU_REMOVED_RETRY:
 			assert_spin_locked(&nlru->lock);
 		case LRU_REMOVED:
 			isolated++;
 			/*
 			 * If the lru lock has been dropped, our list
 			 * traversal is now invalid and so we have to
 			 * restart from scratch.
 			 */
 			if (ret == LRU_REMOVED_RETRY)
 				goto restart;
 			break;
 		case LRU_ROTATE:
 			list_move_tail(item, &l->list);
 			break;
 		case LRU_SKIP:
 			break;
 		case LRU_RETRY:
 			/*
 			 * The lru lock has been dropped, our list traversal is
 			 * now invalid and so we have to restart from scratch.
 			 */
 			assert_spin_locked(&nlru->lock);
 			goto restart;
 		default:
 			BUG();
 		}
 	}

 	spin_unlock(&nlru->lock);
 	return isolated;
 }

 unsigned long
 list_lru_walk_one(struct list_lru *lru, int nid, struct mem_cgroup *memcg,
 		  list_lru_walk_cb isolate, void *cb_arg,
 		  unsigned long *nr_to_walk)
 {
 	return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg),
 				   isolate, cb_arg, nr_to_walk);
 }
 EXPORT_SYMBOL_GPL(list_lru_walk_one);

 unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
 				 list_lru_walk_cb isolate, void *cb_arg,
 				 unsigned long *nr_to_walk)
 {
 	long isolated = 0;
 	int memcg_idx;

 	isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg,
 					nr_to_walk);
 	if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
 		for_each_memcg_cache_index(memcg_idx) {
 			isolated += __list_lru_walk_one(lru, nid, memcg_idx,
 						isolate, cb_arg, nr_to_walk);
 			if (*nr_to_walk <= 0)
 				break;
 		}
 	}
 	return isolated;
 }
 EXPORT_SYMBOL_GPL(list_lru_walk_node);

 static void init_one_lru(struct list_lru_one *l)
 {
 	INIT_LIST_HEAD(&l->list);
 	l->nr_items = 0;
 }

 #if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
 static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
 					  int begin, int end)
 {
 	int i;

 	for (i = begin; i < end; i++)
 		kfree(memcg_lrus->lru[i]);
 }

 static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
 				      int begin, int end)
 {
 	int i;

 	for (i = begin; i < end; i++) {
 		struct list_lru_one *l;

 		l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
 		if (!l)
 			goto fail;

 		init_one_lru(l);
 		memcg_lrus->lru[i] = l;
 	}
 	return 0;
 fail:
 	__memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1);
 	return -ENOMEM;
 }

 static int memcg_init_list_lru_node(struct list_lru_node *nlru)
 {
 	int size = memcg_nr_cache_ids;

 	nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL);
 	if (!nlru->memcg_lrus)
 		return -ENOMEM;

 	if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) {
 		kfree(nlru->memcg_lrus);
 		return -ENOMEM;
 	}

 	return 0;
 }

 static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
 {
 	__memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids);
 	kfree(nlru->memcg_lrus);
 }

 static int memcg_update_list_lru_node(struct list_lru_node *nlru,
 				      int old_size, int new_size)
 {
 	struct list_lru_memcg *old, *new;

 	BUG_ON(old_size > new_size);

 	old = nlru->memcg_lrus;
 	new = kmalloc(new_size * sizeof(void *), GFP_KERNEL);
 	if (!new)
 		return -ENOMEM;

 	if (__memcg_init_list_lru_node(new, old_size, new_size)) {
 		kfree(new);
 		return -ENOMEM;
 	}

 	memcpy(new, old, old_size * sizeof(void *));

 	/*
 	 * The lock guarantees that we won't race with a reader
 	 * (see list_lru_from_memcg_idx).
 	 *
 	 * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 	 * we have to use IRQ-safe primitives here to avoid deadlock.
 	 */
 	spin_lock_irq(&nlru->lock);
 	nlru->memcg_lrus = new;
 	spin_unlock_irq(&nlru->lock);

 	kfree(old);
 	return 0;
 }

 static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
 					      int old_size, int new_size)
 {
 	/* do not bother shrinking the array back to the old size, because we
 	 * cannot handle allocation failures here */
 	__memcg_destroy_list_lru_node(nlru->memcg_lrus, old_size, new_size);
 }

 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 {
 	int i;

 	if (!memcg_aware)
 		return 0;

 	for_each_node(i) {
 		if (memcg_init_list_lru_node(&lru->node[i]))
 			goto fail;
 	}
 	return 0;
 fail:
 	for (i = i - 1; i >= 0; i--) {
 		if (!lru->node[i].memcg_lrus)
 			continue;
 		memcg_destroy_list_lru_node(&lru->node[i]);
 	}
 	return -ENOMEM;
 }

 static void memcg_destroy_list_lru(struct list_lru *lru)
 {
 	int i;

 	if (!list_lru_memcg_aware(lru))
 		return;

 	for_each_node(i)
 		memcg_destroy_list_lru_node(&lru->node[i]);
 }

 static int memcg_update_list_lru(struct list_lru *lru,
 				 int old_size, int new_size)
 {
 	int i;

 	if (!list_lru_memcg_aware(lru))
 		return 0;

 	for_each_node(i) {
 		if (memcg_update_list_lru_node(&lru->node[i],
 					       old_size, new_size))
 			goto fail;
 	}
 	return 0;
 fail:
 	for (i = i - 1; i >= 0; i--) {
 		if (!lru->node[i].memcg_lrus)
 			continue;

 		memcg_cancel_update_list_lru_node(&lru->node[i],
 						  old_size, new_size);
 	}
 	return -ENOMEM;
 }

 static void memcg_cancel_update_list_lru(struct list_lru *lru,
 					 int old_size, int new_size)
 {
 	int i;

 	if (!list_lru_memcg_aware(lru))
 		return;

 	for_each_node(i)
 		memcg_cancel_update_list_lru_node(&lru->node[i],
 						  old_size, new_size);
 }

 int memcg_update_all_list_lrus(int new_size)
 {
 	int ret = 0;
 	struct list_lru *lru;
 	int old_size = memcg_nr_cache_ids;

 	mutex_lock(&list_lrus_mutex);
 	list_for_each_entry(lru, &list_lrus, list) {
 		ret = memcg_update_list_lru(lru, old_size, new_size);
 		if (ret)
 			goto fail;
 	}
 out:
 	mutex_unlock(&list_lrus_mutex);
 	return ret;
 fail:
 	list_for_each_entry_continue_reverse(lru, &list_lrus, list)
 		memcg_cancel_update_list_lru(lru, old_size, new_size);
 	goto out;
 }

 static void memcg_drain_list_lru_node(struct list_lru_node *nlru,
 				      int src_idx, int dst_idx)
 {
 	struct list_lru_one *src, *dst;

 	/*
 	 * Since list_lru_{add,del} may be called under an IRQ-safe lock,
 	 * we have to use IRQ-safe primitives here to avoid deadlock.
 	 */
 	spin_lock_irq(&nlru->lock);

 	src = list_lru_from_memcg_idx(nlru, src_idx);
 	dst = list_lru_from_memcg_idx(nlru, dst_idx);

 	list_splice_init(&src->list, &dst->list);
 	dst->nr_items += src->nr_items;
 	src->nr_items = 0;

 	spin_unlock_irq(&nlru->lock);
 }

 static void memcg_drain_list_lru(struct list_lru *lru,
 				 int src_idx, int dst_idx)
 {
 	int i;

 	if (!list_lru_memcg_aware(lru))
 		return;

 	for_each_node(i)
 		memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx);
 }

 void memcg_drain_all_list_lrus(int src_idx, int dst_idx)
 {
 	struct list_lru *lru;

 	mutex_lock(&list_lrus_mutex);
 	list_for_each_entry(lru, &list_lrus, list)
 		memcg_drain_list_lru(lru, src_idx, dst_idx);
 	mutex_unlock(&list_lrus_mutex);
 }
 #else
 static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
 {
 	return 0;
 }

 static void memcg_destroy_list_lru(struct list_lru *lru)
 {
 }
 #endif /* CONFIG_MEMCG && !CONFIG_SLOB */

 int __list_lru_init(struct list_lru *lru, bool memcg_aware,
 		    struct lock_class_key *key)
 {
 	int i;
 	size_t size = sizeof(*lru->node) * nr_node_ids;
 	int err = -ENOMEM;

 	memcg_get_cache_ids();

 	lru->node = kzalloc(size, GFP_KERNEL);
 	if (!lru->node)
 		goto out;

 	for_each_node(i) {
 		spin_lock_init(&lru->node[i].lock);
 		if (key)
 			lockdep_set_class(&lru->node[i].lock, key);
 		init_one_lru(&lru->node[i].lru);
 	}

 	err = memcg_init_list_lru(lru, memcg_aware);
 	if (err) {
 		kfree(lru->node);
 		goto out;
 	}

 	list_lru_register(lru);
 out:
 	memcg_put_cache_ids();
 	return err;
 }
 EXPORT_SYMBOL_GPL(__list_lru_init);

 void list_lru_destroy(struct list_lru *lru)
 {
 	/* Already destroyed or not yet initialized? */
 	if (!lru->node)
 		return;

 	memcg_get_cache_ids();

 	list_lru_unregister(lru);

 	memcg_destroy_list_lru(lru);
 	kfree(lru->node);
 	lru->node = NULL;

 	memcg_put_cache_ids();
 }
 EXPORT_SYMBOL_GPL(list_lru_destroy);
	/*
	* Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
	* Authors: David Chinner and Glauber Costa
	*
	* Generic LRU infrastructure
	*/
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/mm.h>
	#include <linux/list_lru.h>
	#include <linux/slab.h>
	#include <linux/mutex.h>
	#include <linux/memcontrol.h>

	#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
	static LIST_HEAD(list_lrus);
	static DEFINE_MUTEX(list_lrus_mutex);

	static void list_lru_register(struct list_lru *lru)
	{
	mutex_lock(&list_lrus_mutex);
	list_add(&lru->list, &list_lrus);
	mutex_unlock(&list_lrus_mutex);
	}

	static void list_lru_unregister(struct list_lru *lru)
	{
	mutex_lock(&list_lrus_mutex);
	list_del(&lru->list);
	mutex_unlock(&list_lrus_mutex);
	}
	#else
	static void list_lru_register(struct list_lru *lru)
	{
	}

	static void list_lru_unregister(struct list_lru *lru)
	{
	}
	#endif /* CONFIG_MEMCG && !CONFIG_SLOB */

	#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
	static inline bool list_lru_memcg_aware(struct list_lru *lru)
	{
	/*
	* This needs node 0 to be always present, even
	* in the systems supporting sparse numa ids.
	*/
	return !!lru->node[0].memcg_lrus;
	}

	static inline struct list_lru_one *
	list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
	{
	/*
	* The lock protects the array of per cgroup lists from relocation
	* (see memcg_update_list_lru_node).
	*/
	lockdep_assert_held(&nlru->lock);
	if (nlru->memcg_lrus && idx >= 0)
	return nlru->memcg_lrus->lru[idx];

	return &nlru->lru;
	}

	static __always_inline struct mem_cgroup mem_cgroup_from_kmem(void ptr)
	{
	struct page *page;

	if (!memcg_kmem_enabled())
	return NULL;
	page = virt_to_head_page(ptr);
	return page->mem_cgroup;
	}

	static inline struct list_lru_one *
	list_lru_from_kmem(struct list_lru_node nlru, void ptr)
	{
	struct mem_cgroup *memcg;

	if (!nlru->memcg_lrus)
	return &nlru->lru;

	memcg = mem_cgroup_from_kmem(ptr);
	if (!memcg)
	return &nlru->lru;

	return list_lru_from_memcg_idx(nlru, memcg_cache_id(memcg));
	}
	#else
	static inline bool list_lru_memcg_aware(struct list_lru *lru)
	{
	return false;
	}

	static inline struct list_lru_one *
	list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx)
	{
	return &nlru->lru;
	}

	static inline struct list_lru_one *
	list_lru_from_kmem(struct list_lru_node nlru, void ptr)
	{
	return &nlru->lru;
	}
	#endif /* CONFIG_MEMCG && !CONFIG_SLOB */

	bool list_lru_add(struct list_lru lru, struct list_head item)
	{
	int nid = page_to_nid(virt_to_page(item));
	struct list_lru_node *nlru = &lru->node[nid];
	struct list_lru_one *l;

	spin_lock(&nlru->lock);
	if (list_empty(item)) {
	l = list_lru_from_kmem(nlru, item);
	list_add_tail(item, &l->list);
	l->nr_items++;
	spin_unlock(&nlru->lock);
	return true;
	}
	spin_unlock(&nlru->lock);
	return false;
	}
	EXPORT_SYMBOL_GPL(list_lru_add);

	bool list_lru_del(struct list_lru lru, struct list_head item)
	{
	int nid = page_to_nid(virt_to_page(item));
	struct list_lru_node *nlru = &lru->node[nid];
	struct list_lru_one *l;

	spin_lock(&nlru->lock);
	if (!list_empty(item)) {
	l = list_lru_from_kmem(nlru, item);
	list_del_init(item);
	l->nr_items--;
	spin_unlock(&nlru->lock);
	return true;
	}
	spin_unlock(&nlru->lock);
	return false;
	}
	EXPORT_SYMBOL_GPL(list_lru_del);

	void list_lru_isolate(struct list_lru_one list, struct list_head item)
	{
	list_del_init(item);
	list->nr_items--;
	}
	EXPORT_SYMBOL_GPL(list_lru_isolate);

	void list_lru_isolate_move(struct list_lru_one list, struct list_head item,
	struct list_head *head)
	{
	list_move(item, head);
	list->nr_items--;
	}
	EXPORT_SYMBOL_GPL(list_lru_isolate_move);

	static unsigned long __list_lru_count_one(struct list_lru *lru,
	int nid, int memcg_idx)
	{
	struct list_lru_node *nlru = &lru->node[nid];
	struct list_lru_one *l;
	unsigned long count;

	spin_lock(&nlru->lock);
	l = list_lru_from_memcg_idx(nlru, memcg_idx);
	count = l->nr_items;
	spin_unlock(&nlru->lock);

	return count;
	}

	unsigned long list_lru_count_one(struct list_lru *lru,
	int nid, struct mem_cgroup *memcg)
	{
	return __list_lru_count_one(lru, nid, memcg_cache_id(memcg));
	}
	EXPORT_SYMBOL_GPL(list_lru_count_one);

	unsigned long list_lru_count_node(struct list_lru *lru, int nid)
	{
	long count = 0;
	int memcg_idx;

	count += __list_lru_count_one(lru, nid, -1);
	if (list_lru_memcg_aware(lru)) {
	for_each_memcg_cache_index(memcg_idx)
	count += __list_lru_count_one(lru, nid, memcg_idx);
	}
	return count;
	}
	EXPORT_SYMBOL_GPL(list_lru_count_node);

	static unsigned long
	__list_lru_walk_one(struct list_lru *lru, int nid, int memcg_idx,
	list_lru_walk_cb isolate, void *cb_arg,
	unsigned long *nr_to_walk)
	{

	struct list_lru_node *nlru = &lru->node[nid];
	struct list_lru_one *l;
	struct list_head item, n;
	unsigned long isolated = 0;

	spin_lock(&nlru->lock);
	l = list_lru_from_memcg_idx(nlru, memcg_idx);
	restart:
	list_for_each_safe(item, n, &l->list) {
	enum lru_status ret;

	/*
	* decrement nr_to_walk first so that we don't livelock if we
	* get stuck on large numbesr of LRU_RETRY items
	*/
	if (!*nr_to_walk)
	break;
	--*nr_to_walk;

	ret = isolate(item, l, &nlru->lock, cb_arg);
	switch (ret) {
	case LRU_REMOVED_RETRY:
	assert_spin_locked(&nlru->lock);
	case LRU_REMOVED:
	isolated++;
	/*
	* If the lru lock has been dropped, our list
	* traversal is now invalid and so we have to
	* restart from scratch.
	*/
	if (ret == LRU_REMOVED_RETRY)
	goto restart;
	break;
	case LRU_ROTATE:
	list_move_tail(item, &l->list);
	break;
	case LRU_SKIP:
	break;
	case LRU_RETRY:
	/*
	* The lru lock has been dropped, our list traversal is
	* now invalid and so we have to restart from scratch.
	*/
	assert_spin_locked(&nlru->lock);
	goto restart;
	default:
	BUG();
	}
	}

	spin_unlock(&nlru->lock);
	return isolated;
	}

	unsigned long
	list_lru_walk_one(struct list_lru lru, int nid, struct mem_cgroup memcg,
	list_lru_walk_cb isolate, void *cb_arg,
	unsigned long *nr_to_walk)
	{
	return __list_lru_walk_one(lru, nid, memcg_cache_id(memcg),
	isolate, cb_arg, nr_to_walk);
	}
	EXPORT_SYMBOL_GPL(list_lru_walk_one);

	unsigned long list_lru_walk_node(struct list_lru *lru, int nid,
	list_lru_walk_cb isolate, void *cb_arg,
	unsigned long *nr_to_walk)
	{
	long isolated = 0;
	int memcg_idx;

	isolated += __list_lru_walk_one(lru, nid, -1, isolate, cb_arg,
	nr_to_walk);
	if (*nr_to_walk > 0 && list_lru_memcg_aware(lru)) {
	for_each_memcg_cache_index(memcg_idx) {
	isolated += __list_lru_walk_one(lru, nid, memcg_idx,
	isolate, cb_arg, nr_to_walk);
	if (*nr_to_walk <= 0)
	break;
	}
	}
	return isolated;
	}
	EXPORT_SYMBOL_GPL(list_lru_walk_node);

	static void init_one_lru(struct list_lru_one *l)
	{
	INIT_LIST_HEAD(&l->list);
	l->nr_items = 0;
	}

	#if defined(CONFIG_MEMCG) && !defined(CONFIG_SLOB)
	static void __memcg_destroy_list_lru_node(struct list_lru_memcg *memcg_lrus,
	int begin, int end)
	{
	int i;

	for (i = begin; i < end; i++)
	kfree(memcg_lrus->lru[i]);
	}

	static int __memcg_init_list_lru_node(struct list_lru_memcg *memcg_lrus,
	int begin, int end)
	{
	int i;

	for (i = begin; i < end; i++) {
	struct list_lru_one *l;

	l = kmalloc(sizeof(struct list_lru_one), GFP_KERNEL);
	if (!l)
	goto fail;

	init_one_lru(l);
	memcg_lrus->lru[i] = l;
	}
	return 0;
	fail:
	__memcg_destroy_list_lru_node(memcg_lrus, begin, i - 1);
	return -ENOMEM;
	}

	static int memcg_init_list_lru_node(struct list_lru_node *nlru)
	{
	int size = memcg_nr_cache_ids;

	nlru->memcg_lrus = kmalloc(size * sizeof(void *), GFP_KERNEL);
	if (!nlru->memcg_lrus)
	return -ENOMEM;

	if (__memcg_init_list_lru_node(nlru->memcg_lrus, 0, size)) {
	kfree(nlru->memcg_lrus);
	return -ENOMEM;
	}

	return 0;
	}

	static void memcg_destroy_list_lru_node(struct list_lru_node *nlru)
	{
	__memcg_destroy_list_lru_node(nlru->memcg_lrus, 0, memcg_nr_cache_ids);
	kfree(nlru->memcg_lrus);
	}

	static int memcg_update_list_lru_node(struct list_lru_node *nlru,
	int old_size, int new_size)
	{
	struct list_lru_memcg old, new;

	BUG_ON(old_size > new_size);

	old = nlru->memcg_lrus;
	new = kmalloc(new_size * sizeof(void *), GFP_KERNEL);
	if (!new)
	return -ENOMEM;

	if (__memcg_init_list_lru_node(new, old_size, new_size)) {
	kfree(new);
	return -ENOMEM;
	}

	memcpy(new, old, old_size * sizeof(void *));

	/*
	* The lock guarantees that we won't race with a reader
	* (see list_lru_from_memcg_idx).
	*
	* Since list_lru_{add,del} may be called under an IRQ-safe lock,
	* we have to use IRQ-safe primitives here to avoid deadlock.
	*/
	spin_lock_irq(&nlru->lock);
	nlru->memcg_lrus = new;
	spin_unlock_irq(&nlru->lock);

	kfree(old);
	return 0;
	}

	static void memcg_cancel_update_list_lru_node(struct list_lru_node *nlru,
	int old_size, int new_size)
	{
	/* do not bother shrinking the array back to the old size, because we
	* cannot handle allocation failures here */
	__memcg_destroy_list_lru_node(nlru->memcg_lrus, old_size, new_size);
	}

	static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
	{
	int i;

	if (!memcg_aware)
	return 0;

	for_each_node(i) {
	if (memcg_init_list_lru_node(&lru->node[i]))
	goto fail;
	}
	return 0;
	fail:
	for (i = i - 1; i >= 0; i--) {
	if (!lru->node[i].memcg_lrus)
	continue;
	memcg_destroy_list_lru_node(&lru->node[i]);
	}
	return -ENOMEM;
	}

	static void memcg_destroy_list_lru(struct list_lru *lru)
	{
	int i;

	if (!list_lru_memcg_aware(lru))
	return;

	for_each_node(i)
	memcg_destroy_list_lru_node(&lru->node[i]);
	}

	static int memcg_update_list_lru(struct list_lru *lru,
	int old_size, int new_size)
	{
	int i;

	if (!list_lru_memcg_aware(lru))
	return 0;

	for_each_node(i) {
	if (memcg_update_list_lru_node(&lru->node[i],
	old_size, new_size))
	goto fail;
	}
	return 0;
	fail:
	for (i = i - 1; i >= 0; i--) {
	if (!lru->node[i].memcg_lrus)
	continue;

	memcg_cancel_update_list_lru_node(&lru->node[i],
	old_size, new_size);
	}
	return -ENOMEM;
	}

	static void memcg_cancel_update_list_lru(struct list_lru *lru,
	int old_size, int new_size)
	{
	int i;

	if (!list_lru_memcg_aware(lru))
	return;

	for_each_node(i)
	memcg_cancel_update_list_lru_node(&lru->node[i],
	old_size, new_size);
	}

	int memcg_update_all_list_lrus(int new_size)
	{
	int ret = 0;
	struct list_lru *lru;
	int old_size = memcg_nr_cache_ids;

	mutex_lock(&list_lrus_mutex);
	list_for_each_entry(lru, &list_lrus, list) {
	ret = memcg_update_list_lru(lru, old_size, new_size);
	if (ret)
	goto fail;
	}
	out:
	mutex_unlock(&list_lrus_mutex);
	return ret;
	fail:
	list_for_each_entry_continue_reverse(lru, &list_lrus, list)
	memcg_cancel_update_list_lru(lru, old_size, new_size);
	goto out;
	}

	static void memcg_drain_list_lru_node(struct list_lru_node *nlru,
	int src_idx, int dst_idx)
	{
	struct list_lru_one src, dst;

	/*
	* Since list_lru_{add,del} may be called under an IRQ-safe lock,
	* we have to use IRQ-safe primitives here to avoid deadlock.
	*/
	spin_lock_irq(&nlru->lock);

	src = list_lru_from_memcg_idx(nlru, src_idx);
	dst = list_lru_from_memcg_idx(nlru, dst_idx);

	list_splice_init(&src->list, &dst->list);
	dst->nr_items += src->nr_items;
	src->nr_items = 0;

	spin_unlock_irq(&nlru->lock);
	}

	static void memcg_drain_list_lru(struct list_lru *lru,
	int src_idx, int dst_idx)
	{
	int i;

	if (!list_lru_memcg_aware(lru))
	return;

	for_each_node(i)
	memcg_drain_list_lru_node(&lru->node[i], src_idx, dst_idx);
	}

	void memcg_drain_all_list_lrus(int src_idx, int dst_idx)
	{
	struct list_lru *lru;

	mutex_lock(&list_lrus_mutex);
	list_for_each_entry(lru, &list_lrus, list)
	memcg_drain_list_lru(lru, src_idx, dst_idx);
	mutex_unlock(&list_lrus_mutex);
	}
	#else
	static int memcg_init_list_lru(struct list_lru *lru, bool memcg_aware)
	{
	return 0;
	}

	static void memcg_destroy_list_lru(struct list_lru *lru)
	{
	}
	#endif /* CONFIG_MEMCG && !CONFIG_SLOB */

	int __list_lru_init(struct list_lru *lru, bool memcg_aware,
	struct lock_class_key *key)
	{
	int i;
	size_t size = sizeof(lru->node) nr_node_ids;
	int err = -ENOMEM;

	memcg_get_cache_ids();

	lru->node = kzalloc(size, GFP_KERNEL);
	if (!lru->node)
	goto out;

	for_each_node(i) {
	spin_lock_init(&lru->node[i].lock);
	if (key)
	lockdep_set_class(&lru->node[i].lock, key);
	init_one_lru(&lru->node[i].lru);
	}

	err = memcg_init_list_lru(lru, memcg_aware);
	if (err) {
	kfree(lru->node);
	goto out;
	}

	list_lru_register(lru);
	out:
	memcg_put_cache_ids();
	return err;
	}
	EXPORT_SYMBOL_GPL(__list_lru_init);

	void list_lru_destroy(struct list_lru *lru)
	{
	/* Already destroyed or not yet initialized? */
	if (!lru->node)
	return;

	memcg_get_cache_ids();

	list_lru_unregister(lru);

	memcg_destroy_list_lru(lru);
	kfree(lru->node);
	lru->node = NULL;

	memcg_put_cache_ids();
	}
	EXPORT_SYMBOL_GPL(list_lru_destroy);