mempool: fix first round failure behavior
[linux-2.6.git] / kernel / res_counter.c
blob6d269cce7aa13c4593540f6aa80be389e3ffc720
1 /*
2 * resource cgroups
4 * Copyright 2007 OpenVZ SWsoft Inc
6 * Author: Pavel Emelianov <xemul@openvz.org>
8 */
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>
17 void res_counter_init(struct res_counter *counter, struct res_counter *parent)
19 spin_lock_init(&counter->lock);
20 counter->limit = RESOURCE_MAX;
21 counter->soft_limit = RESOURCE_MAX;
22 counter->parent = parent;
25 int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
27 if (counter->usage + val > counter->limit) {
28 counter->failcnt++;
29 return -ENOMEM;
32 counter->usage += val;
33 if (counter->usage > counter->max_usage)
34 counter->max_usage = counter->usage;
35 return 0;
38 int res_counter_charge(struct res_counter *counter, unsigned long val,
39 struct res_counter **limit_fail_at)
41 int ret;
42 unsigned long flags;
43 struct res_counter *c, *u;
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;
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);
64 done:
65 local_irq_restore(flags);
66 return ret;
69 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
71 if (WARN_ON(counter->usage < val))
72 val = counter->usage;
74 counter->usage -= val;
77 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
79 unsigned long flags;
80 struct res_counter *c;
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);
88 local_irq_restore(flags);
92 static inline unsigned long long *
93 res_counter_member(struct res_counter *counter, int member)
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;
108 BUG();
109 return NULL;
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))
116 unsigned long long *val;
117 char buf[64], *s;
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);
129 #if BITS_PER_LONG == 32
130 u64 res_counter_read_u64(struct res_counter *counter, int member)
132 unsigned long flags;
133 u64 ret;
135 spin_lock_irqsave(&counter->lock, flags);
136 ret = *res_counter_member(counter, member);
137 spin_unlock_irqrestore(&counter->lock, flags);
139 return ret;
141 #else
142 u64 res_counter_read_u64(struct res_counter *counter, int member)
144 return *res_counter_member(counter, member);
146 #endif
148 int res_counter_memparse_write_strategy(const char *buf,
149 unsigned long long *res)
151 char *end;
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;
162 *res = memparse(buf, &end);
163 if (*end != '\0')
164 return -EINVAL;
166 *res = PAGE_ALIGN(*res);
167 return 0;
170 int res_counter_write(struct res_counter *counter, int member,
171 const char *buf, write_strategy_fn write_strategy)
173 char *end;
174 unsigned long flags;
175 unsigned long long tmp, *val;
177 if (write_strategy) {
178 if (write_strategy(buf, &tmp))
179 return -EINVAL;
180 } else {
181 tmp = simple_strtoull(buf, &end, 10);
182 if (*end != '\0')
183 return -EINVAL;
185 spin_lock_irqsave(&counter->lock, flags);
186 val = res_counter_member(counter, member);
187 *val = tmp;
188 spin_unlock_irqrestore(&counter->lock, flags);
189 return 0;