res_counter.c

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    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 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 *res)
  182 {
  183         char *end;
  184 
  185         /* return RESOURCE_MAX(unlimited) if "-1" is specified */
  186         if (*buf == '-') {
  187                 *res = simple_strtoull(buf + 1, &end, 10);
  188                 if (*res != 1 || *end != '\0')
  189                         return -EINVAL;
  190                 *res = RESOURCE_MAX;
  191                 return 0;
  192         }
  193 
  194         *res = memparse(buf, &end);
  195         if (*end != '\0')
  196                 return -EINVAL;
  197 
  198         *res = PAGE_ALIGN(*res);
  199         return 0;
  200 }

Cache object: 1cc466d2fc8cdd37e3494af63b4310e5

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FreeBSD/Linux Kernel Cross Reference sys/kernel/res_counter.c

FreeBSD/Linux Kernel Cross Reference
sys/kernel/res_counter.c