Root/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
17void 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
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;
33    if (counter->usage > counter->max_usage)
34        counter->max_usage = counter->usage;
35    return 0;
36}
37
38int 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;
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);
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;
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
92static inline unsigned long long *
93res_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
112ssize_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
130u64 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
142u64 res_counter_read_u64(struct res_counter *counter, int member)
143{
144    return *res_counter_member(counter, member);
145}
146#endif
147
148int 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
171int 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}
192

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