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/slab.h>
14 #include <linux/res_counter.h>
15 #include <linux/uaccess.h>
16 #include <linux/mm.h>
17
res_counter_init(struct res_counter * counter,struct res_counter * parent)18 void res_counter_init(struct res_counter *counter, struct res_counter *parent)
19 {
20 spin_lock_init(&counter->lock);
21 counter->limit = (unsigned long long)LLONG_MAX;
22 counter->parent = parent;
23 }
24
res_counter_charge_locked(struct res_counter * counter,unsigned long val)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
res_counter_charge(struct res_counter * counter,unsigned long val,struct res_counter ** limit_fail_at)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
res_counter_uncharge_locked(struct res_counter * counter,unsigned long val)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
res_counter_uncharge(struct res_counter * counter,unsigned long val)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 *
res_counter_member(struct res_counter * counter,int member)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 };
105
106 BUG();
107 return NULL;
108 }
109
res_counter_read(struct res_counter * counter,int member,const char __user * userbuf,size_t nbytes,loff_t * pos,int (* read_strategy)(unsigned long long val,char * st_buf))110 ssize_t res_counter_read(struct res_counter *counter, int member,
111 const char __user *userbuf, size_t nbytes, loff_t *pos,
112 int (*read_strategy)(unsigned long long val, char *st_buf))
113 {
114 unsigned long long *val;
115 char buf[64], *s;
116
117 s = buf;
118 val = res_counter_member(counter, member);
119 if (read_strategy)
120 s += read_strategy(*val, s);
121 else
122 s += sprintf(s, "%llu\n", *val);
123 return simple_read_from_buffer((void __user *)userbuf, nbytes,
124 pos, buf, s - buf);
125 }
126
res_counter_read_u64(struct res_counter * counter,int member)127 u64 res_counter_read_u64(struct res_counter *counter, int member)
128 {
129 return *res_counter_member(counter, member);
130 }
131
res_counter_memparse_write_strategy(const char * buf,unsigned long long * res)132 int res_counter_memparse_write_strategy(const char *buf,
133 unsigned long long *res)
134 {
135 char *end;
136 /* FIXME - make memparse() take const char* args */
137 *res = memparse((char *)buf, &end);
138 if (*end != '\0')
139 return -EINVAL;
140
141 *res = PAGE_ALIGN(*res);
142 return 0;
143 }
144
res_counter_write(struct res_counter * counter,int member,const char * buf,write_strategy_fn write_strategy)145 int res_counter_write(struct res_counter *counter, int member,
146 const char *buf, write_strategy_fn write_strategy)
147 {
148 char *end;
149 unsigned long flags;
150 unsigned long long tmp, *val;
151
152 if (write_strategy) {
153 if (write_strategy(buf, &tmp))
154 return -EINVAL;
155 } else {
156 tmp = simple_strtoull(buf, &end, 10);
157 if (*end != '\0')
158 return -EINVAL;
159 }
160 spin_lock_irqsave(&counter->lock, flags);
161 val = res_counter_member(counter, member);
162 *val = tmp;
163 spin_unlock_irqrestore(&counter->lock, flags);
164 return 0;
165 }
166