Pavel Emelianov | e552b66 | 2008-02-07 00:13:49 -0800 | [diff] [blame^] | 1 | #ifndef __RES_COUNTER_H__ |
| 2 | #define __RES_COUNTER_H__ |
| 3 | |
| 4 | /* |
| 5 | * Resource Counters |
| 6 | * Contain common data types and routines for resource accounting |
| 7 | * |
| 8 | * Copyright 2007 OpenVZ SWsoft Inc |
| 9 | * |
| 10 | * Author: Pavel Emelianov <xemul@openvz.org> |
| 11 | * |
| 12 | */ |
| 13 | |
| 14 | #include <linux/cgroup.h> |
| 15 | |
| 16 | /* |
| 17 | * The core object. the cgroup that wishes to account for some |
| 18 | * resource may include this counter into its structures and use |
| 19 | * the helpers described beyond |
| 20 | */ |
| 21 | |
| 22 | struct res_counter { |
| 23 | /* |
| 24 | * the current resource consumption level |
| 25 | */ |
| 26 | unsigned long usage; |
| 27 | /* |
| 28 | * the limit that usage cannot exceed |
| 29 | */ |
| 30 | unsigned long limit; |
| 31 | /* |
| 32 | * the number of unsuccessful attempts to consume the resource |
| 33 | */ |
| 34 | unsigned long failcnt; |
| 35 | /* |
| 36 | * the lock to protect all of the above. |
| 37 | * the routines below consider this to be IRQ-safe |
| 38 | */ |
| 39 | spinlock_t lock; |
| 40 | }; |
| 41 | |
| 42 | /* |
| 43 | * Helpers to interact with userspace |
| 44 | * res_counter_read/_write - put/get the specified fields from the |
| 45 | * res_counter struct to/from the user |
| 46 | * |
| 47 | * @counter: the counter in question |
| 48 | * @member: the field to work with (see RES_xxx below) |
| 49 | * @buf: the buffer to opeate on,... |
| 50 | * @nbytes: its size... |
| 51 | * @pos: and the offset. |
| 52 | */ |
| 53 | |
| 54 | ssize_t res_counter_read(struct res_counter *counter, int member, |
| 55 | const char __user *buf, size_t nbytes, loff_t *pos); |
| 56 | ssize_t res_counter_write(struct res_counter *counter, int member, |
| 57 | const char __user *buf, size_t nbytes, loff_t *pos); |
| 58 | |
| 59 | /* |
| 60 | * the field descriptors. one for each member of res_counter |
| 61 | */ |
| 62 | |
| 63 | enum { |
| 64 | RES_USAGE, |
| 65 | RES_LIMIT, |
| 66 | RES_FAILCNT, |
| 67 | }; |
| 68 | |
| 69 | /* |
| 70 | * helpers for accounting |
| 71 | */ |
| 72 | |
| 73 | void res_counter_init(struct res_counter *counter); |
| 74 | |
| 75 | /* |
| 76 | * charge - try to consume more resource. |
| 77 | * |
| 78 | * @counter: the counter |
| 79 | * @val: the amount of the resource. each controller defines its own |
| 80 | * units, e.g. numbers, bytes, Kbytes, etc |
| 81 | * |
| 82 | * returns 0 on success and <0 if the counter->usage will exceed the |
| 83 | * counter->limit _locked call expects the counter->lock to be taken |
| 84 | */ |
| 85 | |
| 86 | int res_counter_charge_locked(struct res_counter *counter, unsigned long val); |
| 87 | int res_counter_charge(struct res_counter *counter, unsigned long val); |
| 88 | |
| 89 | /* |
| 90 | * uncharge - tell that some portion of the resource is released |
| 91 | * |
| 92 | * @counter: the counter |
| 93 | * @val: the amount of the resource |
| 94 | * |
| 95 | * these calls check for usage underflow and show a warning on the console |
| 96 | * _locked call expects the counter->lock to be taken |
| 97 | */ |
| 98 | |
| 99 | void res_counter_uncharge_locked(struct res_counter *counter, unsigned long val); |
| 100 | void res_counter_uncharge(struct res_counter *counter, unsigned long val); |
| 101 | |
| 102 | #endif |