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