Merge branch 'for-2.6.39' into for-2.6.40
[linux-2.6.git] / kernel / res_counter.c
1 /*
2  * resource cgroups
3  *
4  * Copyright 2007 OpenVZ SWsoft Inc
5  *
6  * Author: Pavel Emelianov <xemul@openvz.org>
7  *
8  */
9
10 #include <linux/types.h>
11 #include <linux/parser.h>
12 #include <linux/fs.h>
13 #include <linux/res_counter.h>
14 #include <linux/uaccess.h>
15 #include <linux/mm.h>
16
17 void res_counter_init(struct res_counter *counter, struct res_counter *parent)
18 {
19         spin_lock_init(&counter->lock);
20         counter->limit = RESOURCE_MAX;
21         counter->soft_limit = RESOURCE_MAX;
22         counter->parent = parent;
23 }
24
25 int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
26 {
27         if (counter->usage + val > counter->limit) {
28                 counter->failcnt++;
29                 return -ENOMEM;
30         }
31
32         counter->usage += val;
33         if (counter->usage > counter->max_usage)
34                 counter->max_usage = counter->usage;
35         return 0;
36 }
37
38 int res_counter_charge(struct res_counter *counter, unsigned long val,
39                         struct res_counter **limit_fail_at)
40 {
41         int ret;
42         unsigned long flags;
43         struct res_counter *c, *u;
44
45         *limit_fail_at = NULL;
46         local_irq_save(flags);
47         for (c = counter; c != NULL; c = c->parent) {
48                 spin_lock(&c->lock);
49                 ret = res_counter_charge_locked(c, val);
50                 spin_unlock(&c->lock);
51                 if (ret < 0) {
52                         *limit_fail_at = c;
53                         goto undo;
54                 }
55         }
56         ret = 0;
57         goto done;
58 undo:
59         for (u = counter; u != c; u = u->parent) {
60                 spin_lock(&u->lock);
61                 res_counter_uncharge_locked(u, val);
62                 spin_unlock(&u->lock);
63         }
64 done:
65         local_irq_restore(flags);
66         return ret;
67 }
68
69 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
70 {
71         if (WARN_ON(counter->usage < val))
72                 val = counter->usage;
73
74         counter->usage -= val;
75 }
76
77 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
78 {
79         unsigned long flags;
80         struct res_counter *c;
81
82         local_irq_save(flags);
83         for (c = counter; c != NULL; c = c->parent) {
84                 spin_lock(&c->lock);
85                 res_counter_uncharge_locked(c, val);
86                 spin_unlock(&c->lock);
87         }
88         local_irq_restore(flags);
89 }
90
91
92 static inline unsigned long long *
93 res_counter_member(struct res_counter *counter, int member)
94 {
95         switch (member) {
96         case RES_USAGE:
97                 return &counter->usage;
98         case RES_MAX_USAGE:
99                 return &counter->max_usage;
100         case RES_LIMIT:
101                 return &counter->limit;
102         case RES_FAILCNT:
103                 return &counter->failcnt;
104         case RES_SOFT_LIMIT:
105                 return &counter->soft_limit;
106         };
107
108         BUG();
109         return NULL;
110 }
111
112 ssize_t res_counter_read(struct res_counter *counter, int member,
113                 const char __user *userbuf, size_t nbytes, loff_t *pos,
114                 int (*read_strategy)(unsigned long long val, char *st_buf))
115 {
116         unsigned long long *val;
117         char buf[64], *s;
118
119         s = buf;
120         val = res_counter_member(counter, member);
121         if (read_strategy)
122                 s += read_strategy(*val, s);
123         else
124                 s += sprintf(s, "%llu\n", *val);
125         return simple_read_from_buffer((void __user *)userbuf, nbytes,
126                         pos, buf, s - buf);
127 }
128
129 #if BITS_PER_LONG == 32
130 u64 res_counter_read_u64(struct res_counter *counter, int member)
131 {
132         unsigned long flags;
133         u64 ret;
134
135         spin_lock_irqsave(&counter->lock, flags);
136         ret = *res_counter_member(counter, member);
137         spin_unlock_irqrestore(&counter->lock, flags);
138
139         return ret;
140 }
141 #else
142 u64 res_counter_read_u64(struct res_counter *counter, int member)
143 {
144         return *res_counter_member(counter, member);
145 }
146 #endif
147
148 int res_counter_memparse_write_strategy(const char *buf,
149                                         unsigned long long *res)
150 {
151         char *end;
152
153         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
154         if (*buf == '-') {
155                 *res = simple_strtoull(buf + 1, &end, 10);
156                 if (*res != 1 || *end != '\0')
157                         return -EINVAL;
158                 *res = RESOURCE_MAX;
159                 return 0;
160         }
161
162         /* FIXME - make memparse() take const char* args */
163         *res = memparse((char *)buf, &end);
164         if (*end != '\0')
165                 return -EINVAL;
166
167         *res = PAGE_ALIGN(*res);
168         return 0;
169 }
170
171 int res_counter_write(struct res_counter *counter, int member,
172                       const char *buf, write_strategy_fn write_strategy)
173 {
174         char *end;
175         unsigned long flags;
176         unsigned long long tmp, *val;
177
178         if (write_strategy) {
179                 if (write_strategy(buf, &tmp))
180                         return -EINVAL;
181         } else {
182                 tmp = simple_strtoull(buf, &end, 10);
183                 if (*end != '\0')
184                         return -EINVAL;
185         }
186         spin_lock_irqsave(&counter->lock, flags);
187         val = res_counter_member(counter, member);
188         *val = tmp;
189         spin_unlock_irqrestore(&counter->lock, flags);
190         return 0;
191 }