kernel/res_counter.c

   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
  17 void 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
  25 int res_counter_charge_locked(struct res_counter *counter, unsigned long val,
  26                               bool force)
  27 {
  28         int ret = 0;
  29
  30         if (counter->usage + val > counter->limit) {
  31                 counter->failcnt++;
  32                 ret = -ENOMEM;
  33                 if (!force)
  34                         return ret;
  35         }
  36
  37         counter->usage += val;
  38         if (counter->usage > counter->max_usage)
  39                 counter->max_usage = counter->usage;
  40         return ret;
  41 }
  42
  43 static int __res_counter_charge(struct res_counter *counter, unsigned long val,
  44                                 struct res_counter **limit_fail_at, bool force)
  45 {
  46         int ret, r;
  47         unsigned long flags;
  48         struct res_counter *c, *u;
  49
  50         r = ret = 0;
  51         *limit_fail_at = NULL;
  52         local_irq_save(flags);
  53         for (c = counter; c != NULL; c = c->parent) {
  54                 spin_lock(&c->lock);
  55                 r = res_counter_charge_locked(c, val, force);
  56                 spin_unlock(&c->lock);
  57                 if (r < 0 && !ret) {
  58                         ret = r;
  59                         *limit_fail_at = c;
  60                         if (!force)
  61                                 break;
  62                 }
  63         }
  64
  65         if (ret < 0 && !force) {
  66                 for (u = counter; u != c; u = u->parent) {
  67                         spin_lock(&u->lock);
  68                         res_counter_uncharge_locked(u, val);
  69                         spin_unlock(&u->lock);
  70                 }
  71         }
  72         local_irq_restore(flags);
  73
  74         return ret;
  75 }
  76
  77 int res_counter_charge(struct res_counter *counter, unsigned long val,
  78                         struct res_counter **limit_fail_at)
  79 {
  80         return __res_counter_charge(counter, val, limit_fail_at, false);
  81 }
  82
  83 int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
  84                               struct res_counter **limit_fail_at)
  85 {
  86         return __res_counter_charge(counter, val, limit_fail_at, true);
  87 }
  88
  89 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
  90 {
  91         if (WARN_ON(counter->usage < val))
  92                 val = counter->usage;
  93
  94         counter->usage -= val;
  95 }
  96
  97 void res_counter_uncharge_until(struct res_counter *counter,
  98                                 struct res_counter *top,
  99                                 unsigned long val)
 100 {
 101         unsigned long flags;
 102         struct res_counter *c;
 103
 104         local_irq_save(flags);
 105         for (c = counter; c != top; c = c->parent) {
 106                 spin_lock(&c->lock);
 107                 res_counter_uncharge_locked(c, val);
 108                 spin_unlock(&c->lock);
 109         }
 110         local_irq_restore(flags);
 111 }
 112
 113 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
 114 {
 115         res_counter_uncharge_until(counter, NULL, val);
 116 }
 117
 118 static inline unsigned long long *
 119 res_counter_member(struct res_counter *counter, int member)
 120 {
 121         switch (member) {
 122         case RES_USAGE:
 123                 return &counter->usage;
 124         case RES_MAX_USAGE:
 125                 return &counter->max_usage;
 126         case RES_LIMIT:
 127                 return &counter->limit;
 128         case RES_FAILCNT:
 129                 return &counter->failcnt;
 130         case RES_SOFT_LIMIT:
 131                 return &counter->soft_limit;
 132         };
 133
 134         BUG();
 135         return NULL;
 136 }
 137
 138 ssize_t res_counter_read(struct res_counter *counter, int member,
 139                 const char __user *userbuf, size_t nbytes, loff_t *pos,
 140                 int (*read_strategy)(unsigned long long val, char *st_buf))
 141 {
 142         unsigned long long *val;
 143         char buf[64], *s;
 144
 145         s = buf;
 146         val = res_counter_member(counter, member);
 147         if (read_strategy)
 148                 s += read_strategy(*val, s);
 149         else
 150                 s += sprintf(s, "%llu\n", *val);
 151         return simple_read_from_buffer((void __user *)userbuf, nbytes,
 152                         pos, buf, s - buf);
 153 }
 154
 155 #if BITS_PER_LONG == 32
 156 u64 res_counter_read_u64(struct res_counter *counter, int member)
 157 {
 158         unsigned long flags;
 159         u64 ret;
 160
 161         spin_lock_irqsave(&counter->lock, flags);
 162         ret = *res_counter_member(counter, member);
 163         spin_unlock_irqrestore(&counter->lock, flags);
 164
 165         return ret;
 166 }
 167 #else
 168 u64 res_counter_read_u64(struct res_counter *counter, int member)
 169 {
 170         return *res_counter_member(counter, member);
 171 }
 172 #endif
 173
 174 int res_counter_memparse_write_strategy(const char *buf,
 175                                         unsigned long long *res)
 176 {
 177         char *end;
 178
 179         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
 180         if (*buf == '-') {
 181                 *res = simple_strtoull(buf + 1, &end, 10);
 182                 if (*res != 1 || *end != '\0')
 183                         return -EINVAL;
 184                 *res = RESOURCE_MAX;
 185                 return 0;
 186         }
 187
 188         *res = memparse(buf, &end);
 189         if (*end != '\0')
 190                 return -EINVAL;
 191
 192         *res = PAGE_ALIGN(*res);
 193         return 0;
 194 }
 195
 196 int res_counter_write(struct res_counter *counter, int member,
 197                       const char *buf, write_strategy_fn write_strategy)
 198 {
 199         char *end;
 200         unsigned long flags;
 201         unsigned long long tmp, *val;
 202
 203         if (write_strategy) {
 204                 if (write_strategy(buf, &tmp))
 205                         return -EINVAL;
 206         } else {
 207                 tmp = simple_strtoull(buf, &end, 10);
 208                 if (*end != '\0')
 209                         return -EINVAL;
 210         }
 211         spin_lock_irqsave(&counter->lock, flags);
 212         val = res_counter_member(counter, member);
 213         *val = tmp;
 214         spin_unlock_irqrestore(&counter->lock, flags);
 215         return 0;
 216 }