summaryrefslogtreecommitdiffstats
path: root/mm/list_lru.c
blob: 86cb55464f71a892c7d765907ea4de5182102001 (plain)
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
/*
 * 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>

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];

	spin_lock(&nlru->lock);
	WARN_ON_ONCE(nlru->nr_items < 0);
	if (list_empty(item)) {
		list_add_tail(item, &nlru->list);
		if (nlru->nr_items++ == 0)
			node_set(nid, lru->active_nodes);
		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];

	spin_lock(&nlru->lock);
	if (!list_empty(item)) {
		list_del_init(item);
		if (--nlru->nr_items == 0)
			node_clear(nid, lru->active_nodes);
		WARN_ON_ONCE(nlru->nr_items < 0);
		spin_unlock(&nlru->lock);
		return true;
	}
	spin_unlock(&nlru->lock);
	return false;
}
EXPORT_SYMBOL_GPL(list_lru_del);

unsigned long
list_lru_count_node(struct list_lru *lru, int nid)
{
	unsigned long count = 0;
	struct list_lru_node *nlru = &lru->node[nid];

	spin_lock(&nlru->lock);
	WARN_ON_ONCE(nlru->nr_items < 0);
	count += nlru->nr_items;
	spin_unlock(&nlru->lock);

	return count;
}
EXPORT_SYMBOL_GPL(list_lru_count_node);

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)
{

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

	spin_lock(&nlru->lock);
restart:
	list_for_each_safe(item, n, &nlru->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) == 0)
			break;

		ret = isolate(item, &nlru->lock, cb_arg);
		switch (ret) {
		case LRU_REMOVED:
			if (--nlru->nr_items == 0)
				node_clear(nid, lru->active_nodes);
			WARN_ON_ONCE(nlru->nr_items < 0);
			isolated++;
			break;
		case LRU_ROTATE:
			list_move_tail(item, &nlru->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.
			 */
			goto restart;
		default:
			BUG();
		}
	}

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

static unsigned long list_lru_dispose_all_node(struct list_lru *lru, int nid,
					       list_lru_dispose_cb dispose)
{
	struct list_lru_node	*nlru = &lru->node[nid];
	LIST_HEAD(dispose_list);
	unsigned long disposed = 0;

	spin_lock(&nlru->lock);
	while (!list_empty(&nlru->list)) {
		list_splice_init(&nlru->list, &dispose_list);
		disposed += nlru->nr_items;
		nlru->nr_items = 0;
		node_clear(nid, lru->active_nodes);
		spin_unlock(&nlru->lock);

		dispose(&dispose_list);

		spin_lock(&nlru->lock);
	}
	spin_unlock(&nlru->lock);
	return disposed;
}

unsigned long list_lru_dispose_all(struct list_lru *lru,
				   list_lru_dispose_cb dispose)
{
	unsigned long disposed;
	unsigned long total = 0;
	int nid;

	do {
		disposed = 0;
		for_each_node_mask(nid, lru->active_nodes) {
			disposed += list_lru_dispose_all_node(lru, nid,
							      dispose);
		}
		total += disposed;
	} while (disposed != 0);

	return total;
}

int list_lru_init(struct list_lru *lru)
{
	int i;

	nodes_clear(lru->active_nodes);
	for (i = 0; i < MAX_NUMNODES; i++) {
		spin_lock_init(&lru->node[i].lock);
		INIT_LIST_HEAD(&lru->node[i].list);
		lru->node[i].nr_items = 0;
	}
	return 0;
}
EXPORT_SYMBOL_GPL(list_lru_init);
OpenPOWER on IntegriCloud