faebe9fdf3
The resource counter is supposed to facilitate the resource accounting of arbitrary resource (and it already does this for memory controller). However, it is about to be used in other resources controllers (swap, kernel memory, networking, etc), so provide a doc describing how to work with it. This will eliminate all the possible future duplications in the appropriate controllers' docs. Fixed errors pointed out by Randy. [akpm@linux-foundation.org: fix documentation tpyo] Signed-off-by: Pavel Emelyanov <xemul@openvz.org> Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
147 lines
3.7 KiB
C
147 lines
3.7 KiB
C
#ifndef __RES_COUNTER_H__
|
|
#define __RES_COUNTER_H__
|
|
|
|
/*
|
|
* Resource Counters
|
|
* Contain common data types and routines for resource accounting
|
|
*
|
|
* Copyright 2007 OpenVZ SWsoft Inc
|
|
*
|
|
* Author: Pavel Emelianov <xemul@openvz.org>
|
|
*
|
|
* See Documentation/controllers/resource_counter.txt for more
|
|
* info about what this counter is.
|
|
*/
|
|
|
|
#include <linux/cgroup.h>
|
|
|
|
/*
|
|
* The core object. the cgroup that wishes to account for some
|
|
* resource may include this counter into its structures and use
|
|
* the helpers described beyond
|
|
*/
|
|
|
|
struct res_counter {
|
|
/*
|
|
* the current resource consumption level
|
|
*/
|
|
unsigned long long usage;
|
|
/*
|
|
* the maximal value of the usage from the counter creation
|
|
*/
|
|
unsigned long long max_usage;
|
|
/*
|
|
* the limit that usage cannot exceed
|
|
*/
|
|
unsigned long long limit;
|
|
/*
|
|
* the number of unsuccessful attempts to consume the resource
|
|
*/
|
|
unsigned long long failcnt;
|
|
/*
|
|
* the lock to protect all of the above.
|
|
* the routines below consider this to be IRQ-safe
|
|
*/
|
|
spinlock_t lock;
|
|
};
|
|
|
|
/**
|
|
* Helpers to interact with userspace
|
|
* res_counter_read_u64() - returns the value of the specified member.
|
|
* res_counter_read/_write - put/get the specified fields from the
|
|
* res_counter struct to/from the user
|
|
*
|
|
* @counter: the counter in question
|
|
* @member: the field to work with (see RES_xxx below)
|
|
* @buf: the buffer to opeate on,...
|
|
* @nbytes: its size...
|
|
* @pos: and the offset.
|
|
*/
|
|
|
|
u64 res_counter_read_u64(struct res_counter *counter, int member);
|
|
|
|
ssize_t res_counter_read(struct res_counter *counter, int member,
|
|
const char __user *buf, size_t nbytes, loff_t *pos,
|
|
int (*read_strategy)(unsigned long long val, char *s));
|
|
ssize_t res_counter_write(struct res_counter *counter, int member,
|
|
const char __user *buf, size_t nbytes, loff_t *pos,
|
|
int (*write_strategy)(char *buf, unsigned long long *val));
|
|
|
|
/*
|
|
* the field descriptors. one for each member of res_counter
|
|
*/
|
|
|
|
enum {
|
|
RES_USAGE,
|
|
RES_MAX_USAGE,
|
|
RES_LIMIT,
|
|
RES_FAILCNT,
|
|
};
|
|
|
|
/*
|
|
* helpers for accounting
|
|
*/
|
|
|
|
void res_counter_init(struct res_counter *counter);
|
|
|
|
/*
|
|
* charge - try to consume more resource.
|
|
*
|
|
* @counter: the counter
|
|
* @val: the amount of the resource. each controller defines its own
|
|
* units, e.g. numbers, bytes, Kbytes, etc
|
|
*
|
|
* returns 0 on success and <0 if the counter->usage will exceed the
|
|
* counter->limit _locked call expects the counter->lock to be taken
|
|
*/
|
|
|
|
int res_counter_charge_locked(struct res_counter *counter, unsigned long val);
|
|
int res_counter_charge(struct res_counter *counter, unsigned long val);
|
|
|
|
/*
|
|
* uncharge - tell that some portion of the resource is released
|
|
*
|
|
* @counter: the counter
|
|
* @val: the amount of the resource
|
|
*
|
|
* these calls check for usage underflow and show a warning on the console
|
|
* _locked call expects the counter->lock to be taken
|
|
*/
|
|
|
|
void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
|
|
void res_counter_uncharge(struct res_counter *counter, unsigned long val);
|
|
|
|
static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
|
|
{
|
|
if (cnt->usage < cnt->limit)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* Helper function to detect if the cgroup is within it's limit or
|
|
* not. It's currently called from cgroup_rss_prepare()
|
|
*/
|
|
static inline bool res_counter_check_under_limit(struct res_counter *cnt)
|
|
{
|
|
bool ret;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cnt->lock, flags);
|
|
ret = res_counter_limit_check_locked(cnt);
|
|
spin_unlock_irqrestore(&cnt->lock, flags);
|
|
return ret;
|
|
}
|
|
|
|
static inline void res_counter_reset_max(struct res_counter *cnt)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&cnt->lock, flags);
|
|
cnt->max_usage = cnt->usage;
|
|
spin_unlock_irqrestore(&cnt->lock, flags);
|
|
}
|
|
|
|
#endif
|