res_counter.c revision 52dcf8a1f8ac09b6ea21266ebdc4db6d52eea1fc
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 *res = memparse(buf, &end); 163 if (*end != '\0') 164 return -EINVAL; 165 166 *res = PAGE_ALIGN(*res); 167 return 0; 168} 169 170int res_counter_write(struct res_counter *counter, int member, 171 const char *buf, write_strategy_fn write_strategy) 172{ 173 char *end; 174 unsigned long flags; 175 unsigned long long tmp, *val; 176 177 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; 184 } 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; 190} 191