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a38e4082 DC |
1 | /* |
2 | * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. | |
3 | * Authors: David Chinner and Glauber Costa | |
4 | * | |
5 | * Generic LRU infrastructure | |
6 | */ | |
7 | #include <linux/kernel.h> | |
8 | #include <linux/module.h> | |
3b1d58a4 | 9 | #include <linux/mm.h> |
a38e4082 | 10 | #include <linux/list_lru.h> |
5ca302c8 | 11 | #include <linux/slab.h> |
c0a5b560 VD |
12 | #include <linux/mutex.h> |
13 | ||
14 | #ifdef CONFIG_MEMCG_KMEM | |
15 | static LIST_HEAD(list_lrus); | |
16 | static DEFINE_MUTEX(list_lrus_mutex); | |
17 | ||
18 | static void list_lru_register(struct list_lru *lru) | |
19 | { | |
20 | mutex_lock(&list_lrus_mutex); | |
21 | list_add(&lru->list, &list_lrus); | |
22 | mutex_unlock(&list_lrus_mutex); | |
23 | } | |
24 | ||
25 | static void list_lru_unregister(struct list_lru *lru) | |
26 | { | |
27 | mutex_lock(&list_lrus_mutex); | |
28 | list_del(&lru->list); | |
29 | mutex_unlock(&list_lrus_mutex); | |
30 | } | |
31 | #else | |
32 | static void list_lru_register(struct list_lru *lru) | |
33 | { | |
34 | } | |
35 | ||
36 | static void list_lru_unregister(struct list_lru *lru) | |
37 | { | |
38 | } | |
39 | #endif /* CONFIG_MEMCG_KMEM */ | |
a38e4082 DC |
40 | |
41 | bool list_lru_add(struct list_lru *lru, struct list_head *item) | |
42 | { | |
3b1d58a4 DC |
43 | int nid = page_to_nid(virt_to_page(item)); |
44 | struct list_lru_node *nlru = &lru->node[nid]; | |
45 | ||
46 | spin_lock(&nlru->lock); | |
47 | WARN_ON_ONCE(nlru->nr_items < 0); | |
a38e4082 | 48 | if (list_empty(item)) { |
3b1d58a4 | 49 | list_add_tail(item, &nlru->list); |
ff0b67ef | 50 | nlru->nr_items++; |
3b1d58a4 | 51 | spin_unlock(&nlru->lock); |
a38e4082 DC |
52 | return true; |
53 | } | |
3b1d58a4 | 54 | spin_unlock(&nlru->lock); |
a38e4082 DC |
55 | return false; |
56 | } | |
57 | EXPORT_SYMBOL_GPL(list_lru_add); | |
58 | ||
59 | bool list_lru_del(struct list_lru *lru, struct list_head *item) | |
60 | { | |
3b1d58a4 DC |
61 | int nid = page_to_nid(virt_to_page(item)); |
62 | struct list_lru_node *nlru = &lru->node[nid]; | |
63 | ||
64 | spin_lock(&nlru->lock); | |
a38e4082 DC |
65 | if (!list_empty(item)) { |
66 | list_del_init(item); | |
ff0b67ef | 67 | nlru->nr_items--; |
3b1d58a4 DC |
68 | WARN_ON_ONCE(nlru->nr_items < 0); |
69 | spin_unlock(&nlru->lock); | |
a38e4082 DC |
70 | return true; |
71 | } | |
3b1d58a4 | 72 | spin_unlock(&nlru->lock); |
a38e4082 DC |
73 | return false; |
74 | } | |
75 | EXPORT_SYMBOL_GPL(list_lru_del); | |
76 | ||
6a4f496f GC |
77 | unsigned long |
78 | list_lru_count_node(struct list_lru *lru, int nid) | |
a38e4082 | 79 | { |
3b1d58a4 | 80 | unsigned long count = 0; |
6a4f496f | 81 | struct list_lru_node *nlru = &lru->node[nid]; |
3b1d58a4 | 82 | |
6a4f496f GC |
83 | spin_lock(&nlru->lock); |
84 | WARN_ON_ONCE(nlru->nr_items < 0); | |
85 | count += nlru->nr_items; | |
86 | spin_unlock(&nlru->lock); | |
3b1d58a4 DC |
87 | |
88 | return count; | |
89 | } | |
6a4f496f | 90 | EXPORT_SYMBOL_GPL(list_lru_count_node); |
3b1d58a4 | 91 | |
6a4f496f | 92 | unsigned long |
3b1d58a4 DC |
93 | list_lru_walk_node(struct list_lru *lru, int nid, list_lru_walk_cb isolate, |
94 | void *cb_arg, unsigned long *nr_to_walk) | |
95 | { | |
96 | ||
97 | struct list_lru_node *nlru = &lru->node[nid]; | |
a38e4082 | 98 | struct list_head *item, *n; |
3b1d58a4 | 99 | unsigned long isolated = 0; |
a38e4082 | 100 | |
3b1d58a4 | 101 | spin_lock(&nlru->lock); |
a38e4082 | 102 | restart: |
3b1d58a4 | 103 | list_for_each_safe(item, n, &nlru->list) { |
a38e4082 | 104 | enum lru_status ret; |
5cedf721 DC |
105 | |
106 | /* | |
107 | * decrement nr_to_walk first so that we don't livelock if we | |
108 | * get stuck on large numbesr of LRU_RETRY items | |
109 | */ | |
c56b097a | 110 | if (!*nr_to_walk) |
5cedf721 | 111 | break; |
c56b097a | 112 | --*nr_to_walk; |
5cedf721 | 113 | |
3b1d58a4 | 114 | ret = isolate(item, &nlru->lock, cb_arg); |
a38e4082 | 115 | switch (ret) { |
449dd698 JW |
116 | case LRU_REMOVED_RETRY: |
117 | assert_spin_locked(&nlru->lock); | |
a38e4082 | 118 | case LRU_REMOVED: |
ff0b67ef | 119 | nlru->nr_items--; |
3b1d58a4 DC |
120 | WARN_ON_ONCE(nlru->nr_items < 0); |
121 | isolated++; | |
449dd698 JW |
122 | /* |
123 | * If the lru lock has been dropped, our list | |
124 | * traversal is now invalid and so we have to | |
125 | * restart from scratch. | |
126 | */ | |
127 | if (ret == LRU_REMOVED_RETRY) | |
128 | goto restart; | |
a38e4082 DC |
129 | break; |
130 | case LRU_ROTATE: | |
3b1d58a4 | 131 | list_move_tail(item, &nlru->list); |
a38e4082 DC |
132 | break; |
133 | case LRU_SKIP: | |
134 | break; | |
135 | case LRU_RETRY: | |
5cedf721 DC |
136 | /* |
137 | * The lru lock has been dropped, our list traversal is | |
138 | * now invalid and so we have to restart from scratch. | |
139 | */ | |
449dd698 | 140 | assert_spin_locked(&nlru->lock); |
a38e4082 DC |
141 | goto restart; |
142 | default: | |
143 | BUG(); | |
144 | } | |
a38e4082 | 145 | } |
3b1d58a4 DC |
146 | |
147 | spin_unlock(&nlru->lock); | |
148 | return isolated; | |
149 | } | |
150 | EXPORT_SYMBOL_GPL(list_lru_walk_node); | |
151 | ||
449dd698 | 152 | int list_lru_init_key(struct list_lru *lru, struct lock_class_key *key) |
a38e4082 | 153 | { |
3b1d58a4 | 154 | int i; |
5ca302c8 GC |
155 | size_t size = sizeof(*lru->node) * nr_node_ids; |
156 | ||
157 | lru->node = kzalloc(size, GFP_KERNEL); | |
158 | if (!lru->node) | |
159 | return -ENOMEM; | |
a38e4082 | 160 | |
5ca302c8 | 161 | for (i = 0; i < nr_node_ids; i++) { |
3b1d58a4 | 162 | spin_lock_init(&lru->node[i].lock); |
449dd698 JW |
163 | if (key) |
164 | lockdep_set_class(&lru->node[i].lock, key); | |
3b1d58a4 DC |
165 | INIT_LIST_HEAD(&lru->node[i].list); |
166 | lru->node[i].nr_items = 0; | |
167 | } | |
c0a5b560 | 168 | list_lru_register(lru); |
a38e4082 DC |
169 | return 0; |
170 | } | |
449dd698 | 171 | EXPORT_SYMBOL_GPL(list_lru_init_key); |
5ca302c8 GC |
172 | |
173 | void list_lru_destroy(struct list_lru *lru) | |
174 | { | |
c0a5b560 VD |
175 | /* Already destroyed or not yet initialized? */ |
176 | if (!lru->node) | |
177 | return; | |
178 | list_lru_unregister(lru); | |
5ca302c8 | 179 | kfree(lru->node); |
c0a5b560 | 180 | lru->node = NULL; |
5ca302c8 GC |
181 | } |
182 | EXPORT_SYMBOL_GPL(list_lru_destroy); |