1 | /* SPDX-License-Identifier: GPL-2.0 */ |
2 | /* |
3 | * Copyright (c) 2013 Red Hat, Inc. and Parallels Inc. All rights reserved. |
4 | * Authors: David Chinner and Glauber Costa |
5 | * |
6 | * Generic LRU infrastructure |
7 | */ |
8 | #ifndef _LRU_LIST_H |
9 | #define _LRU_LIST_H |
10 | |
11 | #include <linux/list.h> |
12 | #include <linux/nodemask.h> |
13 | #include <linux/shrinker.h> |
14 | #include <linux/xarray.h> |
15 | |
16 | struct mem_cgroup; |
17 | |
18 | /* list_lru_walk_cb has to always return one of those */ |
19 | enum lru_status { |
20 | LRU_REMOVED, /* item removed from list */ |
21 | LRU_REMOVED_RETRY, /* item removed, but lock has been |
22 | dropped and reacquired */ |
23 | LRU_ROTATE, /* item referenced, give another pass */ |
24 | LRU_SKIP, /* item cannot be locked, skip */ |
25 | LRU_RETRY, /* item not freeable. May drop the lock |
26 | internally, but has to return locked. */ |
27 | LRU_STOP, /* stop lru list walking. May drop the lock |
28 | internally, but has to return locked. */ |
29 | }; |
30 | |
31 | struct list_lru_one { |
32 | struct list_head list; |
33 | /* may become negative during memcg reparenting */ |
34 | long nr_items; |
35 | }; |
36 | |
37 | struct list_lru_memcg { |
38 | struct rcu_head rcu; |
39 | /* array of per cgroup per node lists, indexed by node id */ |
40 | struct list_lru_one node[]; |
41 | }; |
42 | |
43 | struct list_lru_node { |
44 | /* protects all lists on the node, including per cgroup */ |
45 | spinlock_t lock; |
46 | /* global list, used for the root cgroup in cgroup aware lrus */ |
47 | struct list_lru_one lru; |
48 | long nr_items; |
49 | } ____cacheline_aligned_in_smp; |
50 | |
51 | struct list_lru { |
52 | struct list_lru_node *node; |
53 | #ifdef CONFIG_MEMCG_KMEM |
54 | struct list_head list; |
55 | int shrinker_id; |
56 | bool memcg_aware; |
57 | struct xarray xa; |
58 | #endif |
59 | }; |
60 | |
61 | void list_lru_destroy(struct list_lru *lru); |
62 | int __list_lru_init(struct list_lru *lru, bool memcg_aware, |
63 | struct lock_class_key *key, struct shrinker *shrinker); |
64 | |
65 | #define list_lru_init(lru) \ |
66 | __list_lru_init((lru), false, NULL, NULL) |
67 | #define list_lru_init_memcg(lru, shrinker) \ |
68 | __list_lru_init((lru), true, NULL, shrinker) |
69 | |
70 | int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lru *lru, |
71 | gfp_t gfp); |
72 | void memcg_reparent_list_lrus(struct mem_cgroup *memcg, struct mem_cgroup *parent); |
73 | |
74 | /** |
75 | * list_lru_add: add an element to the lru list's tail |
76 | * @lru: the lru pointer |
77 | * @item: the item to be added. |
78 | * @nid: the node id of the sublist to add the item to. |
79 | * @memcg: the cgroup of the sublist to add the item to. |
80 | * |
81 | * If the element is already part of a list, this function returns doing |
82 | * nothing. Therefore the caller does not need to keep state about whether or |
83 | * not the element already belongs in the list and is allowed to lazy update |
84 | * it. Note however that this is valid for *a* list, not *this* list. If |
85 | * the caller organize itself in a way that elements can be in more than |
86 | * one type of list, it is up to the caller to fully remove the item from |
87 | * the previous list (with list_lru_del() for instance) before moving it |
88 | * to @lru. |
89 | * |
90 | * Return: true if the list was updated, false otherwise |
91 | */ |
92 | bool list_lru_add(struct list_lru *lru, struct list_head *item, int nid, |
93 | struct mem_cgroup *memcg); |
94 | |
95 | /** |
96 | * list_lru_add_obj: add an element to the lru list's tail |
97 | * @lru: the lru pointer |
98 | * @item: the item to be added. |
99 | * |
100 | * This function is similar to list_lru_add(), but the NUMA node and the |
101 | * memcg of the sublist is determined by @item list_head. This assumption is |
102 | * valid for slab objects LRU such as dentries, inodes, etc. |
103 | * |
104 | * Return value: true if the list was updated, false otherwise |
105 | */ |
106 | bool list_lru_add_obj(struct list_lru *lru, struct list_head *item); |
107 | |
108 | /** |
109 | * list_lru_del: delete an element from the lru list |
110 | * @lru: the lru pointer |
111 | * @item: the item to be deleted. |
112 | * @nid: the node id of the sublist to delete the item from. |
113 | * @memcg: the cgroup of the sublist to delete the item from. |
114 | * |
115 | * This function works analogously as list_lru_add() in terms of list |
116 | * manipulation. The comments about an element already pertaining to |
117 | * a list are also valid for list_lru_del(). |
118 | * |
119 | * Return: true if the list was updated, false otherwise |
120 | */ |
121 | bool list_lru_del(struct list_lru *lru, struct list_head *item, int nid, |
122 | struct mem_cgroup *memcg); |
123 | |
124 | /** |
125 | * list_lru_del_obj: delete an element from the lru list |
126 | * @lru: the lru pointer |
127 | * @item: the item to be deleted. |
128 | * |
129 | * This function is similar to list_lru_del(), but the NUMA node and the |
130 | * memcg of the sublist is determined by @item list_head. This assumption is |
131 | * valid for slab objects LRU such as dentries, inodes, etc. |
132 | * |
133 | * Return value: true if the list was updated, false otherwise. |
134 | */ |
135 | bool list_lru_del_obj(struct list_lru *lru, struct list_head *item); |
136 | |
137 | /** |
138 | * list_lru_count_one: return the number of objects currently held by @lru |
139 | * @lru: the lru pointer. |
140 | * @nid: the node id to count from. |
141 | * @memcg: the cgroup to count from. |
142 | * |
143 | * There is no guarantee that the list is not updated while the count is being |
144 | * computed. Callers that want such a guarantee need to provide an outer lock. |
145 | * |
146 | * Return: 0 for empty lists, otherwise the number of objects |
147 | * currently held by @lru. |
148 | */ |
149 | unsigned long list_lru_count_one(struct list_lru *lru, |
150 | int nid, struct mem_cgroup *memcg); |
151 | unsigned long list_lru_count_node(struct list_lru *lru, int nid); |
152 | |
153 | static inline unsigned long list_lru_shrink_count(struct list_lru *lru, |
154 | struct shrink_control *sc) |
155 | { |
156 | return list_lru_count_one(lru, nid: sc->nid, memcg: sc->memcg); |
157 | } |
158 | |
159 | static inline unsigned long list_lru_count(struct list_lru *lru) |
160 | { |
161 | long count = 0; |
162 | int nid; |
163 | |
164 | for_each_node_state(nid, N_NORMAL_MEMORY) |
165 | count += list_lru_count_node(lru, nid); |
166 | |
167 | return count; |
168 | } |
169 | |
170 | void list_lru_isolate(struct list_lru_one *list, struct list_head *item); |
171 | void list_lru_isolate_move(struct list_lru_one *list, struct list_head *item, |
172 | struct list_head *head); |
173 | |
174 | typedef enum lru_status (*list_lru_walk_cb)(struct list_head *item, |
175 | struct list_lru_one *list, spinlock_t *lock, void *cb_arg); |
176 | |
177 | /** |
178 | * list_lru_walk_one: walk a @lru, isolating and disposing freeable items. |
179 | * @lru: the lru pointer. |
180 | * @nid: the node id to scan from. |
181 | * @memcg: the cgroup to scan from. |
182 | * @isolate: callback function that is responsible for deciding what to do with |
183 | * the item currently being scanned |
184 | * @cb_arg: opaque type that will be passed to @isolate |
185 | * @nr_to_walk: how many items to scan. |
186 | * |
187 | * This function will scan all elements in a particular @lru, calling the |
188 | * @isolate callback for each of those items, along with the current list |
189 | * spinlock and a caller-provided opaque. The @isolate callback can choose to |
190 | * drop the lock internally, but *must* return with the lock held. The callback |
191 | * will return an enum lru_status telling the @lru infrastructure what to |
192 | * do with the object being scanned. |
193 | * |
194 | * Please note that @nr_to_walk does not mean how many objects will be freed, |
195 | * just how many objects will be scanned. |
196 | * |
197 | * Return: the number of objects effectively removed from the LRU. |
198 | */ |
199 | unsigned long list_lru_walk_one(struct list_lru *lru, |
200 | int nid, struct mem_cgroup *memcg, |
201 | list_lru_walk_cb isolate, void *cb_arg, |
202 | unsigned long *nr_to_walk); |
203 | /** |
204 | * list_lru_walk_one_irq: walk a @lru, isolating and disposing freeable items. |
205 | * @lru: the lru pointer. |
206 | * @nid: the node id to scan from. |
207 | * @memcg: the cgroup to scan from. |
208 | * @isolate: callback function that is responsible for deciding what to do with |
209 | * the item currently being scanned |
210 | * @cb_arg: opaque type that will be passed to @isolate |
211 | * @nr_to_walk: how many items to scan. |
212 | * |
213 | * Same as list_lru_walk_one() except that the spinlock is acquired with |
214 | * spin_lock_irq(). |
215 | */ |
216 | unsigned long list_lru_walk_one_irq(struct list_lru *lru, |
217 | int nid, struct mem_cgroup *memcg, |
218 | list_lru_walk_cb isolate, void *cb_arg, |
219 | unsigned long *nr_to_walk); |
220 | unsigned long list_lru_walk_node(struct list_lru *lru, int nid, |
221 | list_lru_walk_cb isolate, void *cb_arg, |
222 | unsigned long *nr_to_walk); |
223 | |
224 | static inline unsigned long |
225 | list_lru_shrink_walk(struct list_lru *lru, struct shrink_control *sc, |
226 | list_lru_walk_cb isolate, void *cb_arg) |
227 | { |
228 | return list_lru_walk_one(lru, nid: sc->nid, memcg: sc->memcg, isolate, cb_arg, |
229 | nr_to_walk: &sc->nr_to_scan); |
230 | } |
231 | |
232 | static inline unsigned long |
233 | list_lru_shrink_walk_irq(struct list_lru *lru, struct shrink_control *sc, |
234 | list_lru_walk_cb isolate, void *cb_arg) |
235 | { |
236 | return list_lru_walk_one_irq(lru, nid: sc->nid, memcg: sc->memcg, isolate, cb_arg, |
237 | nr_to_walk: &sc->nr_to_scan); |
238 | } |
239 | |
240 | static inline unsigned long |
241 | list_lru_walk(struct list_lru *lru, list_lru_walk_cb isolate, |
242 | void *cb_arg, unsigned long nr_to_walk) |
243 | { |
244 | long isolated = 0; |
245 | int nid; |
246 | |
247 | for_each_node_state(nid, N_NORMAL_MEMORY) { |
248 | isolated += list_lru_walk_node(lru, nid, isolate, |
249 | cb_arg, nr_to_walk: &nr_to_walk); |
250 | if (nr_to_walk <= 0) |
251 | break; |
252 | } |
253 | return isolated; |
254 | } |
255 | #endif /* _LRU_LIST_H */ |
256 | |