res_counter.c revision 28dbc4b6a01fb579a9441c7b81e3d3413dc452df 
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
18void 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
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	};
105
106	BUG();
107	return NULL;
108}
109
110ssize_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
127u64 res_counter_read_u64(struct res_counter *counter, int member)
128{
129	return *res_counter_member(counter, member);
130}
131
132int 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
145int 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