2 * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved.
3 * Authors: David Chinner and Glauber Costa
5 * Generic LRU infrastructure
7 #include <linux/kernel.h>
8 #include <linux/module.h>
10 #include <linux/list_lru.h>
11 #include <linux/slab.h>
13 bool list_lru_add(struct list_lru *lru, struct list_head *item)
15 int nid = page_to_nid(virt_to_page(item));
16 struct list_lru_node *nlru = &lru->node[nid];
18 spin_lock(&nlru->lock);
19 WARN_ON_ONCE(nlru->nr_items < 0);
20 if (list_empty(item)) {
21 list_add_tail(item, &nlru->list);
22 if (nlru->nr_items++ == 0)
23 node_set(nid, lru->active_nodes);
24 spin_unlock(&nlru->lock);
27 spin_unlock(&nlru->lock);
30 EXPORT_SYMBOL_GPL(list_lru_add);
32 bool list_lru_del(struct list_lru *lru, struct list_head *item)
34 int nid = page_to_nid(virt_to_page(item));
35 struct list_lru_node *nlru = &lru->node[nid];
37 spin_lock(&nlru->lock);
38 if (!list_empty(item)) {
40 if (--nlru->nr_items == 0)
41 node_clear(nid, lru->active_nodes);
42 WARN_ON_ONCE(nlru->nr_items < 0);
43 spin_unlock(&nlru->lock);
46 spin_unlock(&nlru->lock);
49 EXPORT_SYMBOL_GPL(list_lru_del);
52 list_lru_count_node(struct list_lru *lru, int nid)
54 unsigned long count = 0;
55 struct list_lru_node *nlru = &lru->node[nid];
57 spin_lock(&nlru->lock);
58 WARN_ON_ONCE(nlru->nr_items < 0);
59 count += nlru->nr_items;
60 spin_unlock(&nlru->lock);
64 EXPORT_SYMBOL_GPL(list_lru_count_node);
67 list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate,
68 void *cb_arg, unsigned long *nr_to_walk)
71 struct list_lru_node *nlru = &lru->node[nid];
72 struct list_head *item, *n;
73 unsigned long isolated = 0;
75 * If we don't keep state of at which pass we are, we can loop at
76 * LRU_RETRY, since we have no guarantees that the caller will be able
77 * to do something other than retry on the next pass. We handle this by
78 * allowing at most one retry per object. This should not be altered
79 * by any condition other than LRU_RETRY.
81 bool first_pass = true;
83 spin_lock(&nlru->lock);
85 list_for_each_safe(item, n, &nlru->list) {
87 ret = isolate(item, &nlru->lock, cb_arg);
90 if (--nlru->nr_items == 0)
91 node_clear(nid, lru->active_nodes);
92 WARN_ON_ONCE(nlru->nr_items < 0);
96 list_move_tail(item, &nlru->list);
111 if ((*nr_to_walk)-- == 0)
116 spin_unlock(&nlru->lock);
119 EXPORT_SYMBOL_GPL(list_lru_walk_node);
121 int list_lru_init(struct list_lru *lru)
124 size_t size = sizeof(*lru->node) * nr_node_ids;
126 lru->node = kzalloc(size, GFP_KERNEL);
130 nodes_clear(lru->active_nodes);
131 for (i = 0; i < nr_node_ids; i++) {
132 spin_lock_init(&lru->node[i].lock);
133 INIT_LIST_HEAD(&lru->node[i].list);
134 lru->node[i].nr_items = 0;
138 EXPORT_SYMBOL_GPL(list_lru_init);
140 void list_lru_destroy(struct list_lru *lru)
144 EXPORT_SYMBOL_GPL(list_lru_destroy);