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 = RES_COUNTER_MAX;
  21         counter->soft_limit = RES_COUNTER_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 u64 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         return counter->usage;
  96 }
  97
  98 u64 res_counter_uncharge_until(struct res_counter *counter,
  99                                struct res_counter *top,
 100                                unsigned long val)
 101 {
 102         unsigned long flags;
 103         struct res_counter *c;
 104         u64 ret = 0;
 105
 106         local_irq_save(flags);
 107         for (c = counter; c != top; c = c->parent) {
 108                 u64 r;
 109                 spin_lock(&c->lock);
 110                 r = res_counter_uncharge_locked(c, val);
 111                 if (c == counter)
 112                         ret = r;
 113                 spin_unlock(&c->lock);
 114         }
 115         local_irq_restore(flags);
 116         return ret;
 117 }
 118
 119 u64 res_counter_uncharge(struct res_counter *counter, unsigned long val)
 120 {
 121         return res_counter_uncharge_until(counter, NULL, val);
 122 }
 123
 124 static inline unsigned long long *
 125 res_counter_member(struct res_counter *counter, int member)
 126 {
 127         switch (member) {
 128         case RES_USAGE:
 129                 return &counter->usage;
 130         case RES_MAX_USAGE:
 131                 return &counter->max_usage;
 132         case RES_LIMIT:
 133                 return &counter->limit;
 134         case RES_FAILCNT:
 135                 return &counter->failcnt;
 136         case RES_SOFT_LIMIT:
 137                 return &counter->soft_limit;
 138         };
 139
 140         BUG();
 141         return NULL;
 142 }
 143
 144 ssize_t res_counter_read(struct res_counter *counter, int member,
 145                 const char __user *userbuf, size_t nbytes, loff_t *pos,
 146                 int (*read_strategy)(unsigned long long val, char *st_buf))
 147 {
 148         unsigned long long *val;
 149         char buf[64], *s;
 150
 151         s = buf;
 152         val = res_counter_member(counter, member);
 153         if (read_strategy)
 154                 s += read_strategy(*val, s);
 155         else
 156                 s += sprintf(s, "%llu\n", *val);
 157         return simple_read_from_buffer((void __user *)userbuf, nbytes,
 158                         pos, buf, s - buf);
 159 }
 160
 161 #if BITS_PER_LONG == 32
 162 u64 res_counter_read_u64(struct res_counter *counter, int member)
 163 {
 164         unsigned long flags;
 165         u64 ret;
 166
 167         spin_lock_irqsave(&counter->lock, flags);
 168         ret = *res_counter_member(counter, member);
 169         spin_unlock_irqrestore(&counter->lock, flags);
 170
 171         return ret;
 172 }
 173 #else
 174 u64 res_counter_read_u64(struct res_counter *counter, int member)
 175 {
 176         return *res_counter_member(counter, member);
 177 }
 178 #endif
 179
 180 int res_counter_memparse_write_strategy(const char *buf,
 181                                         unsigned long long *resp)
 182 {
 183         char *end;
 184         unsigned long long res;
 185
 186         /* return RES_COUNTER_MAX(unlimited) if "-1" is specified */
 187         if (*buf == '-') {
 188                 res = simple_strtoull(buf + 1, &end, 10);
 189                 if (res != 1 || *end != '\0')
 190                         return -EINVAL;
 191                 *resp = RES_COUNTER_MAX;
 192                 return 0;
 193         }
 194
 195         res = memparse(buf, &end);
 196         if (*end != '\0')
 197                 return -EINVAL;
 198
 199         if (PAGE_ALIGN(res) >= res)
 200                 res = PAGE_ALIGN(res);
 201         else
 202                 res = RES_COUNTER_MAX;
 203
 204         *resp = res;
 205
 206         return 0;
 207 }