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/*
* resource cgroups
*
* Copyright 2007 OpenVZ SWsoft Inc
*
* Author: Pavel Emelianov <xemul@openvz.org>
*
*/
#include <linux/types.h>
#include <linux/parser.h>
#include <linux/fs.h>
#include <linux/res_counter.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
void res_counter_init(struct res_counter *counter, struct res_counter *parent)
{
spin_lock_init(&counter->lock);
counter->limit = RES_COUNTER_MAX;
counter->soft_limit = RES_COUNTER_MAX;
counter->parent = parent;
}
static u64 res_counter_uncharge_locked(struct res_counter *counter,
unsigned long val)
{
if (WARN_ON(counter->usage < val))
val = counter->usage;
counter->usage -= val;
return counter->usage;
}
static int res_counter_charge_locked(struct res_counter *counter,
unsigned long val, bool force)
{
int ret = 0;
if (counter->usage + val > counter->limit) {
counter->failcnt++;
ret = -ENOMEM;
if (!force)
return ret;
}
counter->usage += val;
if (counter->usage > counter->max_usage)
counter->max_usage = counter->usage;
return ret;
}
static int __res_counter_charge(struct res_counter *counter, unsigned long val,
struct res_counter **limit_fail_at, bool force)
{
int ret, r;
unsigned long flags;
struct res_counter *c, *u;
r = ret = 0;
*limit_fail_at = NULL;
local_irq_save(flags);
for (c = counter; c != NULL; c = c->parent) {
spin_lock(&c->lock);
r = res_counter_charge_locked(c, val, force);
spin_unlock(&c->lock);
if (r < 0 && !ret) {
ret = r;
*limit_fail_at = c;
if (!force)
break;
}
}
if (ret < 0 && !force) {
for (u = counter; u != c; u = u->parent) {
spin_lock(&u->lock);
res_counter_uncharge_locked(u, val);
spin_unlock(&u->lock);
}
}
local_irq_restore(flags);
return ret;
}
int res_counter_charge(struct res_counter *counter, unsigned long val,
struct res_counter **limit_fail_at)
{
return __res_counter_charge(counter, val, limit_fail_at, false);
}
int res_counter_charge_nofail(struct res_counter *counter, unsigned long val,
struct res_counter **limit_fail_at)
{
return __res_counter_charge(counter, val, limit_fail_at, true);
}
u64 res_counter_uncharge_until(struct res_counter *counter,
struct res_counter *top,
unsigned long val)
{
unsigned long flags;
struct res_counter *c;
u64 ret = 0;
local_irq_save(flags);
for (c = counter; c != top; c = c->parent) {
u64 r;
spin_lock(&c->lock);
r = res_counter_uncharge_locked(c, val);
if (c == counter)
ret = r;
spin_unlock(&c->lock);
}
local_irq_restore(flags);
return ret;
}
u64 res_counter_uncharge(struct res_counter *counter, unsigned long val)
{
return res_counter_uncharge_until(counter, NULL, val);
}
static inline unsigned long long *
res_counter_member(struct res_counter *counter, int member)
{
switch (member) {
case RES_USAGE:
return &counter->usage;
case RES_MAX_USAGE:
return &counter->max_usage;
case RES_LIMIT:
return &counter->limit;
case RES_FAILCNT:
return &counter->failcnt;
case RES_SOFT_LIMIT:
return &counter->soft_limit;
};
BUG();
return NULL;
}
ssize_t res_counter_read(struct res_counter *counter, int member,
const char __user *userbuf, size_t nbytes, loff_t *pos,
int (*read_strategy)(unsigned long long val, char *st_buf))
{
unsigned long long *val;
char buf[64], *s;
s = buf;
val = res_counter_member(counter, member);
if (read_strategy)
s += read_strategy(*val, s);
else
s += sprintf(s, "%llu\n", *val);
return simple_read_from_buffer((void __user *)userbuf, nbytes,
pos, buf, s - buf);
}
#if BITS_PER_LONG == 32
u64 res_counter_read_u64(struct res_counter *counter, int member)
{
unsigned long flags;
u64 ret;
spin_lock_irqsave(&counter->lock, flags);
ret = *res_counter_member(counter, member);
spin_unlock_irqrestore(&counter->lock, flags);
return ret;
}
#else
u64 res_counter_read_u64(struct res_counter *counter, int member)
{
return *res_counter_member(counter, member);
}
#endif
int res_counter_memparse_write_strategy(const char *buf,
unsigned long long *resp)
{
char *end;
unsigned long long res;
/* return RES_COUNTER_MAX(unlimited) if "-1" is specified */
if (*buf == '-') {
int rc = kstrtoull(buf + 1, 10, &res);
if (rc)
return rc;
if (res != 1)
return -EINVAL;
*resp = RES_COUNTER_MAX;
return 0;
}
res = memparse(buf, &end);
if (*end != '\0')
return -EINVAL;
if (PAGE_ALIGN(res) >= res)
res = PAGE_ALIGN(res);
else
res = RES_COUNTER_MAX;
*resp = res;
return 0;
}
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