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