kernel-ark/include/linux/res_counter.h
Balbir Singh 0eea103017 Memory controller improve user interface
Change the interface to use bytes instead of pages.  Page sizes can vary
across platforms and configurations.  A new strategy routine has been added
to the resource counters infrastructure to format the data as desired.

Suggested by David Rientjes, Andrew Morton and Herbert Poetzl

Tested on a UML setup with the config for memory control enabled.

[kamezawa.hiroyu@jp.fujitsu.com: possible race fix in res_counter]
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Cc: Paul Menage <menage@google.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Kirill Korotaev <dev@sw.ru>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: David Rientjes <rientjes@google.com>
Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-02-07 08:42:18 -08:00

128 lines
3.1 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>
*
*/
#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 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/_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.
*/
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_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;
}
#endif