linux/kernel/res_counter.c
Paul Menage 856c13aa1f cgroup files: convert res_counter_write() to be a cgroups write_string() handler
Currently res_counter_write() is a raw file handler even though it's
ultimately taking a number, since in some cases it wants to
pre-process the string when converting it to a number.

This patch converts res_counter_write() from a raw file handler to a
write_string() handler; this allows some of the boilerplate
copying/locking/checking to be removed, and simplies the cleanup path,
since these functions are now performed by the cgroups framework.

[lizf@cn.fujitsu.com: build fix]
Signed-off-by: Paul Menage <menage@google.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-07-25 10:53:36 -07:00

140 lines
3.0 KiB
C

/*
* 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/slab.h>
#include <linux/res_counter.h>
#include <linux/uaccess.h>
#include <linux/mm.h>
void res_counter_init(struct res_counter *counter)
{
spin_lock_init(&counter->lock);
counter->limit = (unsigned long long)LLONG_MAX;
}
int res_counter_charge_locked(struct res_counter *counter, unsigned long val)
{
if (counter->usage + val > counter->limit) {
counter->failcnt++;
return -ENOMEM;
}
counter->usage += val;
if (counter->usage > counter->max_usage)
counter->max_usage = counter->usage;
return 0;
}
int res_counter_charge(struct res_counter *counter, unsigned long val)
{
int ret;
unsigned long flags;
spin_lock_irqsave(&counter->lock, flags);
ret = res_counter_charge_locked(counter, val);
spin_unlock_irqrestore(&counter->lock, flags);
return ret;
}
void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val)
{
if (WARN_ON(counter->usage < val))
val = counter->usage;
counter->usage -= val;
}
void res_counter_uncharge(struct res_counter *counter, unsigned long val)
{
unsigned long flags;
spin_lock_irqsave(&counter->lock, flags);
res_counter_uncharge_locked(counter, val);
spin_unlock_irqrestore(&counter->lock, flags);
}
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;
};
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);
}
u64 res_counter_read_u64(struct res_counter *counter, int member)
{
return *res_counter_member(counter, member);
}
int res_counter_memparse_write_strategy(const char *buf,
unsigned long long *res)
{
char *end;
/* FIXME - make memparse() take const char* args */
*res = memparse((char *)buf, &end);
if (*end != '\0')
return -EINVAL;
*res = PAGE_ALIGN(*res);
return 0;
}
int res_counter_write(struct res_counter *counter, int member,
const char *buf, write_strategy_fn write_strategy)
{
char *end;
unsigned long flags;
unsigned long long tmp, *val;
if (write_strategy) {
if (write_strategy(buf, &tmp))
return -EINVAL;
} else {
tmp = simple_strtoull(buf, &end, 10);
if (*end != '\0')
return -EINVAL;
}
spin_lock_irqsave(&counter->lock, flags);
val = res_counter_member(counter, member);
*val = tmp;
spin_unlock_irqrestore(&counter->lock, flags);
return 0;
}