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/slab.h>
  14 #include <linux/res_counter.h>
  15 #include <linux/uaccess.h>
  16 #include <linux/mm.h>
  17
  18 void res_counter_init(struct res_counter *counter, struct res_counter *parent)
  19 {
  20         spin_lock_init(&counter->lock);
  21         counter->limit = RESOURCE_MAX;
  22         counter->soft_limit = RESOURCE_MAX;
  23         counter->parent = parent;
  24 }
  25
  26 int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
  27 {
  28         if (counter->usage + val > counter->limit) {
  29                 counter->failcnt++;
  30                 return -ENOMEM;
  31         }
  32
  33         counter->usage += val;
  34         if (counter->usage > counter->max_usage)
  35                 counter->max_usage = counter->usage;
  36         return 0;
  37 }
  38
  39 int res_counter_charge(struct res_counter *counter, unsigned long val,
  40                         struct res_counter **limit_fail_at)
  41 {
  42         int ret;
  43         unsigned long flags;
  44         struct res_counter *c, *u;
  45
  46         *limit_fail_at = NULL;
  47         local_irq_save(flags);
  48         for (c = counter; c != NULL; c = c->parent) {
  49                 spin_lock(&c->lock);
  50                 ret = res_counter_charge_locked(c, val);
  51                 spin_unlock(&c->lock);
  52                 if (ret < 0) {
  53                         *limit_fail_at = c;
  54                         goto undo;
  55                 }
  56         }
  57         ret = 0;
  58         goto done;
  59 undo:
  60         for (u = counter; u != c; u = u->parent) {
  61                 spin_lock(&u->lock);
  62                 res_counter_uncharge_locked(u, val);
  63                 spin_unlock(&u->lock);
  64         }
  65 done:
  66         local_irq_restore(flags);
  67         return ret;
  68 }
  69
  70 void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
  71 {
  72         if (WARN_ON(counter->usage < val))
  73                 val = counter->usage;
  74
  75         counter->usage -= val;
  76 }
  77
  78 void res_counter_uncharge(struct res_counter *counter, unsigned long val)
  79 {
  80         unsigned long flags;
  81         struct res_counter *c;
  82
  83         local_irq_save(flags);
  84         for (c = counter; c != NULL; c = c->parent) {
  85                 spin_lock(&c->lock);
  86                 res_counter_uncharge_locked(c, val);
  87                 spin_unlock(&c->lock);
  88         }
  89         local_irq_restore(flags);
  90 }
  91
  92
  93 static inline unsigned long long *
  94 res_counter_member(struct res_counter *counter, int member)
  95 {
  96         switch (member) {
  97         case RES_USAGE:
  98                 return &counter->usage;
  99         case RES_MAX_USAGE:
 100                 return &counter->max_usage;
 101         case RES_LIMIT:
 102                 return &counter->limit;
 103         case RES_FAILCNT:
 104                 return &counter->failcnt;
 105         case RES_SOFT_LIMIT:
 106                 return &counter->soft_limit;
 107         };
 108
 109         BUG();
 110         return NULL;
 111 }
 112
 113 ssize_t res_counter_read(struct res_counter *counter, int member,
 114                 const char __user *userbuf, size_t nbytes, loff_t *pos,
 115                 int (*read_strategy)(unsigned long long val, char *st_buf))
 116 {
 117         unsigned long long *val;
 118         char buf[64], *s;
 119
 120         s = buf;
 121         val = res_counter_member(counter, member);
 122         if (read_strategy)
 123                 s += read_strategy(*val, s);
 124         else
 125                 s += sprintf(s, "%llu\n", *val);
 126         return simple_read_from_buffer((void __user *)userbuf, nbytes,
 127                         pos, buf, s - buf);
 128 }
 129
 130 u64 res_counter_read_u64(struct res_counter *counter, int member)
 131 {
 132         return *res_counter_member(counter, member);
 133 }
 134
 135 int res_counter_memparse_write_strategy(const char *buf,
 136                                         unsigned long long *res)
 137 {
 138         char *end;
 139
 140         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
 141         if (*buf == '-') {
 142                 *res = simple_strtoull(buf + 1, &end, 10);
 143                 if (*res != 1 || *end != '\0')
 144                         return -EINVAL;
 145                 *res = RESOURCE_MAX;
 146                 return 0;
 147         }
 148
 149         /* FIXME - make memparse() take const char* args */
 150         *res = memparse((char *)buf, &end);
 151         if (*end != '\0')
 152                 return -EINVAL;
 153
 154         *res = PAGE_ALIGN(*res);
 155         return 0;
 156 }
 157
 158 int res_counter_write(struct res_counter *counter, int member,
 159                       const char *buf, write_strategy_fn write_strategy)
 160 {
 161         char *end;
 162         unsigned long flags;
 163         unsigned long long tmp, *val;
 164
 165         if (write_strategy) {
 166                 if (write_strategy(buf, &tmp))
 167                         return -EINVAL;
 168         } else {
 169                 tmp = simple_strtoull(buf, &end, 10);
 170                 if (*end != '\0')
 171                         return -EINVAL;
 172         }
 173         spin_lock_irqsave(&counter->lock, flags);
 174         val = res_counter_member(counter, member);
 175         *val = tmp;
 176         spin_unlock_irqrestore(&counter->lock, flags);
 177         return 0;
 178 }