res_counter.c revision f64c3f54940d6929a2b6dcffaab942bd62be2e66 
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 = RESOURCE_MAX;
22	counter->soft_limit = RESOURCE_MAX;
23	counter->parent = parent;
24}
25
26int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
27{
28	if (counter->usage + val > counter->limit) {
29		counter->failcnt++;
30		return -ENOMEM;
31	}
32
33	counter->usage += val;
34	if (counter->usage > counter->max_usage)
35		counter->max_usage = counter->usage;
36	return 0;
37}
38
39int res_counter_charge(struct res_counter *counter, unsigned long val,
40			struct res_counter **limit_fail_at,
41			struct res_counter **soft_limit_fail_at)
42{
43	int ret;
44	unsigned long flags;
45	struct res_counter *c, *u;
46
47	*limit_fail_at = NULL;
48	if (soft_limit_fail_at)
49		*soft_limit_fail_at = NULL;
50	local_irq_save(flags);
51	for (c = counter; c != NULL; c = c->parent) {
52		spin_lock(&c->lock);
53		ret = res_counter_charge_locked(c, val);
54		/*
55		 * With soft limits, we return the highest ancestor
56		 * that exceeds its soft limit
57		 */
58		if (soft_limit_fail_at &&
59			!res_counter_soft_limit_check_locked(c))
60			*soft_limit_fail_at = c;
61		spin_unlock(&c->lock);
62		if (ret < 0) {
63			*limit_fail_at = c;
64			goto undo;
65		}
66	}
67	ret = 0;
68	goto done;
69undo:
70	for (u = counter; u != c; u = u->parent) {
71		spin_lock(&u->lock);
72		res_counter_uncharge_locked(u, val);
73		spin_unlock(&u->lock);
74	}
75done:
76	local_irq_restore(flags);
77	return ret;
78}
79
80void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
81{
82	if (WARN_ON(counter->usage < val))
83		val = counter->usage;
84
85	counter->usage -= val;
86}
87
88void res_counter_uncharge(struct res_counter *counter, unsigned long val,
89				bool *was_soft_limit_excess)
90{
91	unsigned long flags;
92	struct res_counter *c;
93
94	local_irq_save(flags);
95	for (c = counter; c != NULL; c = c->parent) {
96		spin_lock(&c->lock);
97		if (was_soft_limit_excess)
98			*was_soft_limit_excess =
99				!res_counter_soft_limit_check_locked(c);
100		res_counter_uncharge_locked(c, val);
101		spin_unlock(&c->lock);
102	}
103	local_irq_restore(flags);
104}
105
106
107static inline unsigned long long *
108res_counter_member(struct res_counter *counter, int member)
109{
110	switch (member) {
111	case RES_USAGE:
112		return &counter->usage;
113	case RES_MAX_USAGE:
114		return &counter->max_usage;
115	case RES_LIMIT:
116		return &counter->limit;
117	case RES_FAILCNT:
118		return &counter->failcnt;
119	case RES_SOFT_LIMIT:
120		return &counter->soft_limit;
121	};
122
123	BUG();
124	return NULL;
125}
126
127ssize_t res_counter_read(struct res_counter *counter, int member,
128		const char __user *userbuf, size_t nbytes, loff_t *pos,
129		int (*read_strategy)(unsigned long long val, char *st_buf))
130{
131	unsigned long long *val;
132	char buf[64], *s;
133
134	s = buf;
135	val = res_counter_member(counter, member);
136	if (read_strategy)
137		s += read_strategy(*val, s);
138	else
139		s += sprintf(s, "%llu\n", *val);
140	return simple_read_from_buffer((void __user *)userbuf, nbytes,
141			pos, buf, s - buf);
142}
143
144u64 res_counter_read_u64(struct res_counter *counter, int member)
145{
146	return *res_counter_member(counter, member);
147}
148
149int res_counter_memparse_write_strategy(const char *buf,
150					unsigned long long *res)
151{
152	char *end;
153
154	/* return RESOURCE_MAX(unlimited) if "-1" is specified */
155	if (*buf == '-') {
156		*res = simple_strtoull(buf + 1, &end, 10);
157		if (*res != 1 || *end != '\0')
158			return -EINVAL;
159		*res = RESOURCE_MAX;
160		return 0;
161	}
162
163	/* FIXME - make memparse() take const char* args */
164	*res = memparse((char *)buf, &end);
165	if (*end != '\0')
166		return -EINVAL;
167
168	*res = PAGE_ALIGN(*res);
169	return 0;
170}
171
172int res_counter_write(struct res_counter *counter, int member,
173		      const char *buf, write_strategy_fn write_strategy)
174{
175	char *end;
176	unsigned long flags;
177	unsigned long long tmp, *val;
178
179	if (write_strategy) {
180		if (write_strategy(buf, &tmp))
181			return -EINVAL;
182	} else {
183		tmp = simple_strtoull(buf, &end, 10);
184		if (*end != '\0')
185			return -EINVAL;
186	}
187	spin_lock_irqsave(&counter->lock, flags);
188	val = res_counter_member(counter, member);
189	*val = tmp;
190	spin_unlock_irqrestore(&counter->lock, flags);
191	return 0;
192}
193