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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#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */
30
31#ifdef CONFIG_TASK_DELAY_ACCT
32
33extern int delayacct_on; /* Delay accounting turned on/off */
34extern struct kmem_cache *delayacct_cache;
35extern void delayacct_init(void);
36extern void __delayacct_tsk_init(struct task_struct *);
37extern void __delayacct_tsk_exit(struct task_struct *);
38extern void __delayacct_blkio_start(void);
39extern void __delayacct_blkio_end(void);
40extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
41extern __u64 __delayacct_blkio_ticks(struct task_struct *);
42
43static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
44{
45 if (p->delays)
46 return (p->delays->flags & DELAYACCT_PF_BLKIO);
47 else
48 return 0;
49}
50
51static inline void delayacct_set_flag(int flag)
52{
53 if (current->delays)
54 current->delays->flags |= flag;
55}
56
57static inline void delayacct_clear_flag(int flag)
58{
59 if (current->delays)
60 current->delays->flags &= ~flag;
61}
62
63static inline void delayacct_tsk_init(struct task_struct *tsk)
64{
65 /* reinitialize in case parent's non-null pointer was dup'ed*/
66 tsk->delays = NULL;
67 if (delayacct_on)
68 __delayacct_tsk_init(tsk);
69}
70
71/* Free tsk->delays. Called from bad fork and __put_task_struct
72 * where there's no risk of tsk->delays being accessed elsewhere
73 */
74static inline void delayacct_tsk_free(struct task_struct *tsk)
75{
76 if (tsk->delays)
77 kmem_cache_free(delayacct_cache, tsk->delays);
78 tsk->delays = NULL;
79}
80
81static inline void delayacct_blkio_start(void)
82{
83 delayacct_set_flag(DELAYACCT_PF_BLKIO);
84 if (current->delays)
85 __delayacct_blkio_start();
86}
87
88static inline void delayacct_blkio_end(void)
89{
90 if (current->delays)
91 __delayacct_blkio_end();
92 delayacct_clear_flag(DELAYACCT_PF_BLKIO);
93}
94
95static inline int delayacct_add_tsk(struct taskstats *d,
96 struct task_struct *tsk)
97{
98 if (!delayacct_on || !tsk->delays)
99 return 0;
100 return __delayacct_add_tsk(d, tsk);
101}
102
103static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
104{
105 if (tsk->delays)
106 return __delayacct_blkio_ticks(tsk);
107 return 0;
108}
109
110#else
111static inline void delayacct_set_flag(int flag)
112{}
113static inline void delayacct_clear_flag(int flag)
114{}
115static inline void delayacct_init(void)
116{}
117static inline void delayacct_tsk_init(struct task_struct *tsk)
118{}
119static inline void delayacct_tsk_free(struct task_struct *tsk)
120{}
121static inline void delayacct_blkio_start(void)
122{}
123static inline void delayacct_blkio_end(void)
124{}
125static inline int delayacct_add_tsk(struct taskstats *d,
126 struct task_struct *tsk)
127{ return 0; }
128static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
129{ return 0; }
130static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
131{ return 0; }
132#endif /* CONFIG_TASK_DELAY_ACCT */
133
134#endif