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(struct res_counter *counter, unsigned long val)
  98 {
  99         unsigned long flags;
 100         struct res_counter *c;
 101
 102         local_irq_save(flags);
 103         for (c = counter; c != NULL; c = c->parent) {
 104                 spin_lock(&c->lock);
 105                 res_counter_uncharge_locked(c, val);
 106                 spin_unlock(&c->lock);
 107         }
 108         local_irq_restore(flags);
 109 }
 110
 111
 112 static inline unsigned long long *
 113 res_counter_member(struct res_counter *counter, int member)
 114 {
 115         switch (member) {
 116         case RES_USAGE:
 117                 return &counter->usage;
 118         case RES_MAX_USAGE:
 119                 return &counter->max_usage;
 120         case RES_LIMIT:
 121                 return &counter->limit;
 122         case RES_FAILCNT:
 123                 return &counter->failcnt;
 124         case RES_SOFT_LIMIT:
 125                 return &counter->soft_limit;
 126         };
 127
 128         BUG();
 129         return NULL;
 130 }
 131
 132 ssize_t res_counter_read(struct res_counter *counter, int member,
 133                 const char __user *userbuf, size_t nbytes, loff_t *pos,
 134                 int (*read_strategy)(unsigned long long val, char *st_buf))
 135 {
 136         unsigned long long *val;
 137         char buf[64], *s;
 138
 139         s = buf;
 140         val = res_counter_member(counter, member);
 141         if (read_strategy)
 142                 s += read_strategy(*val, s);
 143         else
 144                 s += sprintf(s, "%llu\n", *val);
 145         return simple_read_from_buffer((void __user *)userbuf, nbytes,
 146                         pos, buf, s - buf);
 147 }
 148
 149 #if BITS_PER_LONG == 32
 150 u64 res_counter_read_u64(struct res_counter *counter, int member)
 151 {
 152         unsigned long flags;
 153         u64 ret;
 154
 155         spin_lock_irqsave(&counter->lock, flags);
 156         ret = *res_counter_member(counter, member);
 157         spin_unlock_irqrestore(&counter->lock, flags);
 158
 159         return ret;
 160 }
 161 #else
 162 u64 res_counter_read_u64(struct res_counter *counter, int member)
 163 {
 164         return *res_counter_member(counter, member);
 165 }
 166 #endif
 167
 168 int res_counter_memparse_write_strategy(const char *buf,
 169                                         unsigned long long *res)
 170 {
 171         char *end;
 172
 173         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
 174         if (*buf == '-') {
 175                 *res = simple_strtoull(buf + 1, &end, 10);
 176                 if (*res != 1 || *end != '\0')
 177                         return -EINVAL;
 178                 *res = RESOURCE_MAX;
 179                 return 0;
 180         }
 181
 182         *res = memparse(buf, &end);
 183         if (*end != '\0')
 184                 return -EINVAL;
 185
 186         *res = PAGE_ALIGN(*res);
 187         return 0;
 188 }
 189
 190 int res_counter_write(struct res_counter *counter, int member,
 191                       const char *buf, write_strategy_fn write_strategy)
 192 {
 193         char *end;
 194         unsigned long flags;
 195         unsigned long long tmp, *val;
 196
 197         if (write_strategy) {
 198                 if (write_strategy(buf, &tmp))
 199                         return -EINVAL;
 200         } else {
 201                 tmp = simple_strtoull(buf, &end, 10);
 202                 if (*end != '\0')
 203                         return -EINVAL;
 204         }
 205         spin_lock_irqsave(&counter->lock, flags);
 206         val = res_counter_member(counter, member);
 207         *val = tmp;
 208         spin_unlock_irqrestore(&counter->lock, flags);
 209         return 0;
 210 }