[PATCH] per-task-delay-accounting: delay accounting usage of taskstats interface
[linux-3.10.git] / include / linux / delayacct.h
1 /* delayacct.h - per-task delay accounting
2  *
3  * Copyright (C) Shailabh Nagar, IBM Corp. 2006
4  *
5  * This program is free software;  you can redistribute it and/or modify
6  * it under the terms of the GNU General Public License as published by
7  * the Free Software Foundation; either version 2 of the License, or
8  * (at your option) any later version.
9  *
10  * This program is distributed in the hope that it will be useful,
11  * but WITHOUT ANY WARRANTY;  without even the implied warranty of
12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
13  * the GNU General Public License for more details.
14  *
15  */
16
17 #ifndef _LINUX_DELAYACCT_H
18 #define _LINUX_DELAYACCT_H
19
20 #include <linux/sched.h>
21 #include <linux/taskstats_kern.h>
22
23 /*
24  * Per-task flags relevant to delay accounting
25  * maintained privately to avoid exhausting similar flags in sched.h:PF_*
26  * Used to set current->delays->flags
27  */
28 #define DELAYACCT_PF_SWAPIN     0x00000001      /* I am doing a swapin */
29
30 #ifdef CONFIG_TASK_DELAY_ACCT
31
32 extern int delayacct_on;        /* Delay accounting turned on/off */
33 extern kmem_cache_t *delayacct_cache;
34 extern void delayacct_init(void);
35 extern void __delayacct_tsk_init(struct task_struct *);
36 extern void __delayacct_tsk_exit(struct task_struct *);
37 extern void __delayacct_blkio_start(void);
38 extern void __delayacct_blkio_end(void);
39 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
40
41 static inline void delayacct_set_flag(int flag)
42 {
43         if (current->delays)
44                 current->delays->flags |= flag;
45 }
46
47 static inline void delayacct_clear_flag(int flag)
48 {
49         if (current->delays)
50                 current->delays->flags &= ~flag;
51 }
52
53 static inline void delayacct_tsk_init(struct task_struct *tsk)
54 {
55         /* reinitialize in case parent's non-null pointer was dup'ed*/
56         tsk->delays = NULL;
57         if (unlikely(delayacct_on))
58                 __delayacct_tsk_init(tsk);
59 }
60
61 static inline void delayacct_tsk_exit(struct task_struct *tsk)
62 {
63         if (tsk->delays)
64                 __delayacct_tsk_exit(tsk);
65 }
66
67 static inline void delayacct_blkio_start(void)
68 {
69         if (current->delays)
70                 __delayacct_blkio_start();
71 }
72
73 static inline void delayacct_blkio_end(void)
74 {
75         if (current->delays)
76                 __delayacct_blkio_end();
77 }
78
79 static inline int delayacct_add_tsk(struct taskstats *d,
80                                         struct task_struct *tsk)
81 {
82         if (likely(!delayacct_on))
83                 return -EINVAL;
84         if (!tsk->delays)
85                 return 0;
86         return __delayacct_add_tsk(d, tsk);
87 }
88
89 #else
90 static inline void delayacct_set_flag(int flag)
91 {}
92 static inline void delayacct_clear_flag(int flag)
93 {}
94 static inline void delayacct_init(void)
95 {}
96 static inline void delayacct_tsk_init(struct task_struct *tsk)
97 {}
98 static inline void delayacct_tsk_exit(struct task_struct *tsk)
99 {}
100 static inline void delayacct_blkio_start(void)
101 {}
102 static inline void delayacct_blkio_end(void)
103 {}
104 static inline int delayacct_add_tsk(struct taskstats *d,
105                                         struct task_struct *tsk)
106 { return 0; }
107 #endif /* CONFIG_TASK_DELAY_ACCT */
108
109 #endif