[PATCH] per-task-delay-accounting: sync block I/O and swapin delay collection
[linux-2.6.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
22 /*
23  * Per-task flags relevant to delay accounting
24  * maintained privately to avoid exhausting similar flags in sched.h:PF_*
25  * Used to set current->delays->flags
26  */
27 #define DELAYACCT_PF_SWAPIN     0x00000001      /* I am doing a swapin */
28
29 #ifdef CONFIG_TASK_DELAY_ACCT
30
31 extern int delayacct_on;        /* Delay accounting turned on/off */
32 extern kmem_cache_t *delayacct_cache;
33 extern void delayacct_init(void);
34 extern void __delayacct_tsk_init(struct task_struct *);
35 extern void __delayacct_tsk_exit(struct task_struct *);
36 extern void __delayacct_blkio_start(void);
37 extern void __delayacct_blkio_end(void);
38
39 static inline void delayacct_set_flag(int flag)
40 {
41         if (current->delays)
42                 current->delays->flags |= flag;
43 }
44
45 static inline void delayacct_clear_flag(int flag)
46 {
47         if (current->delays)
48                 current->delays->flags &= ~flag;
49 }
50
51 static inline void delayacct_tsk_init(struct task_struct *tsk)
52 {
53         /* reinitialize in case parent's non-null pointer was dup'ed*/
54         tsk->delays = NULL;
55         if (unlikely(delayacct_on))
56                 __delayacct_tsk_init(tsk);
57 }
58
59 static inline void delayacct_tsk_exit(struct task_struct *tsk)
60 {
61         if (tsk->delays)
62                 __delayacct_tsk_exit(tsk);
63 }
64
65 static inline void delayacct_blkio_start(void)
66 {
67         if (current->delays)
68                 __delayacct_blkio_start();
69 }
70
71 static inline void delayacct_blkio_end(void)
72 {
73         if (current->delays)
74                 __delayacct_blkio_end();
75 }
76
77 #else
78 static inline void delayacct_set_flag(int flag)
79 {}
80 static inline void delayacct_clear_flag(int flag)
81 {}
82 static inline void delayacct_init(void)
83 {}
84 static inline void delayacct_tsk_init(struct task_struct *tsk)
85 {}
86 static inline void delayacct_tsk_exit(struct task_struct *tsk)
87 {}
88 static inline void delayacct_blkio_start(void)
89 {}
90 static inline void delayacct_blkio_end(void)
91 {}
92 #endif /* CONFIG_TASK_DELAY_ACCT */
93
94 #endif