135 lines
2.8 KiB
C
135 lines
2.8 KiB
C
/*
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* resource cgroups
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*
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* Copyright 2007 OpenVZ SWsoft Inc
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*
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* Author: Pavel Emelianov <xemul@openvz.org>
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*
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*/
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#include <linux/types.h>
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#include <linux/parser.h>
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#include <linux/fs.h>
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#include <linux/res_counter.h>
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#include <linux/uaccess.h>
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void res_counter_init(struct res_counter *counter)
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{
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spin_lock_init(&counter->lock);
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counter->limit = (unsigned long long)LLONG_MAX;
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}
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int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
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{
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if (counter->usage + val > counter->limit) {
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counter->failcnt++;
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return -ENOMEM;
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}
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counter->usage += val;
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return 0;
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}
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int res_counter_charge(struct res_counter *counter, unsigned long val)
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{
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int ret;
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unsigned long flags;
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spin_lock_irqsave(&counter->lock, flags);
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ret = res_counter_charge_locked(counter, val);
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spin_unlock_irqrestore(&counter->lock, flags);
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return ret;
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}
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void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
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{
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if (WARN_ON(counter->usage < val))
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val = counter->usage;
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counter->usage -= val;
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}
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void res_counter_uncharge(struct res_counter *counter, unsigned long val)
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{
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unsigned long flags;
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spin_lock_irqsave(&counter->lock, flags);
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res_counter_uncharge_locked(counter, val);
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spin_unlock_irqrestore(&counter->lock, flags);
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}
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static inline unsigned long long *
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res_counter_member(struct res_counter *counter, int member)
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{
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switch (member) {
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case RES_USAGE:
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return &counter->usage;
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case RES_LIMIT:
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return &counter->limit;
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case RES_FAILCNT:
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return &counter->failcnt;
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};
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BUG();
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return NULL;
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}
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ssize_t res_counter_read(struct res_counter *counter, int member,
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const char __user *userbuf, size_t nbytes, loff_t *pos,
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int (*read_strategy)(unsigned long long val, char *st_buf))
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{
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unsigned long long *val;
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char buf[64], *s;
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s = buf;
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val = res_counter_member(counter, member);
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if (read_strategy)
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s += read_strategy(*val, s);
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else
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s += sprintf(s, "%llu\n", *val);
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return simple_read_from_buffer((void __user *)userbuf, nbytes,
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pos, buf, s - buf);
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}
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ssize_t res_counter_write(struct res_counter *counter, int member,
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const char __user *userbuf, size_t nbytes, loff_t *pos,
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int (*write_strategy)(char *st_buf, unsigned long long *val))
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{
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int ret;
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char *buf, *end;
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unsigned long flags;
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unsigned long long tmp, *val;
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buf = kmalloc(nbytes + 1, GFP_KERNEL);
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ret = -ENOMEM;
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if (buf == NULL)
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goto out;
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buf[nbytes] = '\0';
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ret = -EFAULT;
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if (copy_from_user(buf, userbuf, nbytes))
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goto out_free;
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ret = -EINVAL;
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if (write_strategy) {
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if (write_strategy(buf, &tmp)) {
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goto out_free;
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}
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} else {
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tmp = simple_strtoull(buf, &end, 10);
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if (*end != '\0')
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goto out_free;
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}
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spin_lock_irqsave(&counter->lock, flags);
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val = res_counter_member(counter, member);
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*val = tmp;
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spin_unlock_irqrestore(&counter->lock, flags);
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ret = nbytes;
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out_free:
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kfree(buf);
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out:
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return ret;
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}
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