128 lines
3.1 KiB
C
128 lines
3.1 KiB
C
#ifndef __RES_COUNTER_H__
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#define __RES_COUNTER_H__
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/*
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* Resource Counters
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* Contain common data types and routines for resource accounting
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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/cgroup.h>
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/*
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* The core object. the cgroup that wishes to account for some
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* resource may include this counter into its structures and use
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* the helpers described beyond
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*/
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struct res_counter {
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/*
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* the current resource consumption level
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*/
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unsigned long long usage;
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/*
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* the limit that usage cannot exceed
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*/
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unsigned long long limit;
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/*
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* the number of unsuccessful attempts to consume the resource
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*/
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unsigned long long failcnt;
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/*
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* the lock to protect all of the above.
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* the routines below consider this to be IRQ-safe
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*/
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spinlock_t lock;
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};
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/*
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* Helpers to interact with userspace
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* res_counter_read/_write - put/get the specified fields from the
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* res_counter struct to/from the user
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*
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* @counter: the counter in question
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* @member: the field to work with (see RES_xxx below)
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* @buf: the buffer to opeate on,...
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* @nbytes: its size...
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* @pos: and the offset.
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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 *buf, size_t nbytes, loff_t *pos,
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int (*read_strategy)(unsigned long long val, char *s));
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ssize_t res_counter_write(struct res_counter *counter, int member,
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const char __user *buf, size_t nbytes, loff_t *pos,
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int (*write_strategy)(char *buf, unsigned long long *val));
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/*
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* the field descriptors. one for each member of res_counter
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*/
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enum {
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RES_USAGE,
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RES_LIMIT,
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RES_FAILCNT,
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};
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/*
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* helpers for accounting
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*/
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void res_counter_init(struct res_counter *counter);
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/*
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* charge - try to consume more resource.
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*
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* @counter: the counter
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* @val: the amount of the resource. each controller defines its own
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* units, e.g. numbers, bytes, Kbytes, etc
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*
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* returns 0 on success and <0 if the counter->usage will exceed the
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* counter->limit _locked call expects the counter->lock to be taken
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*/
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int res_counter_charge_locked(struct res_counter *counter, unsigned long val);
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int res_counter_charge(struct res_counter *counter, unsigned long val);
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/*
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* uncharge - tell that some portion of the resource is released
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*
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* @counter: the counter
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* @val: the amount of the resource
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*
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* these calls check for usage underflow and show a warning on the console
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* _locked call expects the counter->lock to be taken
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*/
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void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val);
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void res_counter_uncharge(struct res_counter *counter, unsigned long val);
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static inline bool res_counter_limit_check_locked(struct res_counter *cnt)
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{
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if (cnt->usage < cnt->limit)
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return true;
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return false;
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}
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/*
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* Helper function to detect if the cgroup is within it's limit or
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* not. It's currently called from cgroup_rss_prepare()
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*/
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static inline bool res_counter_check_under_limit(struct res_counter *cnt)
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{
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bool ret;
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unsigned long flags;
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spin_lock_irqsave(&cnt->lock, flags);
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ret = res_counter_limit_check_locked(cnt);
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spin_unlock_irqrestore(&cnt->lock, flags);
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return ret;
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}
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#endif
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