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