Merge branch 'perfcounters-fixes-for-linus' of git://git.kernel.org/pub/scm/linux...
[linux-block.git] / kernel / res_counter.c
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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>
1aeb272c 13#include <linux/slab.h>
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14#include <linux/res_counter.h>
15#include <linux/uaccess.h>
856c13aa 16#include <linux/mm.h>
e552b661 17
28dbc4b6 18void res_counter_init(struct res_counter *counter, struct res_counter *parent)
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19{
20 spin_lock_init(&counter->lock);
c5b947b2 21 counter->limit = RESOURCE_MAX;
28dbc4b6 22 counter->parent = parent;
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23}
24
25int 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;
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33 if (counter->usage > counter->max_usage)
34 counter->max_usage = counter->usage;
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35 return 0;
36}
37
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38int res_counter_charge(struct res_counter *counter, unsigned long val,
39 struct res_counter **limit_fail_at)
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40{
41 int ret;
42 unsigned long flags;
28dbc4b6 43 struct res_counter *c, *u;
e552b661 44
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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;
58undo:
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 }
64done:
65 local_irq_restore(flags);
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66 return ret;
67}
68
69void 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
77void res_counter_uncharge(struct res_counter *counter, unsigned long val)
78{
79 unsigned long flags;
28dbc4b6 80 struct res_counter *c;
e552b661 81
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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);
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89}
90
91
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92static inline unsigned long long *
93res_counter_member(struct res_counter *counter, int member)
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94{
95 switch (member) {
96 case RES_USAGE:
97 return &counter->usage;
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98 case RES_MAX_USAGE:
99 return &counter->max_usage;
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100 case RES_LIMIT:
101 return &counter->limit;
102 case RES_FAILCNT:
103 return &counter->failcnt;
104 };
105
106 BUG();
107 return NULL;
108}
109
110ssize_t res_counter_read(struct res_counter *counter, int member,
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111 const char __user *userbuf, size_t nbytes, loff_t *pos,
112 int (*read_strategy)(unsigned long long val, char *st_buf))
e552b661 113{
0eea1030 114 unsigned long long *val;
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115 char buf[64], *s;
116
117 s = buf;
118 val = res_counter_member(counter, member);
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119 if (read_strategy)
120 s += read_strategy(*val, s);
121 else
122 s += sprintf(s, "%llu\n", *val);
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123 return simple_read_from_buffer((void __user *)userbuf, nbytes,
124 pos, buf, s - buf);
125}
126
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127u64 res_counter_read_u64(struct res_counter *counter, int member)
128{
129 return *res_counter_member(counter, member);
130}
131
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132int res_counter_memparse_write_strategy(const char *buf,
133 unsigned long long *res)
e552b661 134{
856c13aa 135 char *end;
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136
137 /* return RESOURCE_MAX(unlimited) if "-1" is specified */
138 if (*buf == '-') {
139 *res = simple_strtoull(buf + 1, &end, 10);
140 if (*res != 1 || *end != '\0')
141 return -EINVAL;
142 *res = RESOURCE_MAX;
143 return 0;
144 }
145
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146 /* FIXME - make memparse() take const char* args */
147 *res = memparse((char *)buf, &end);
148 if (*end != '\0')
149 return -EINVAL;
e552b661 150
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151 *res = PAGE_ALIGN(*res);
152 return 0;
153}
e552b661 154
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155int res_counter_write(struct res_counter *counter, int member,
156 const char *buf, write_strategy_fn write_strategy)
157{
158 char *end;
159 unsigned long flags;
160 unsigned long long tmp, *val;
e552b661 161
0eea1030 162 if (write_strategy) {
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163 if (write_strategy(buf, &tmp))
164 return -EINVAL;
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165 } else {
166 tmp = simple_strtoull(buf, &end, 10);
167 if (*end != '\0')
856c13aa 168 return -EINVAL;
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169 }
170 spin_lock_irqsave(&counter->lock, flags);
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171 val = res_counter_member(counter, member);
172 *val = tmp;
0eea1030 173 spin_unlock_irqrestore(&counter->lock, flags);
856c13aa 174 return 0;
e552b661 175}