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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
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#define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */
29
30#ifdef CONFIG_TASK_DELAY_ACCT
31
32extern int delayacct_on; /* Delay accounting turned on/off */
33extern struct kmem_cache *delayacct_cache;
34extern void delayacct_init(void);
35extern void __delayacct_tsk_init(struct task_struct *);
36extern void __delayacct_tsk_exit(struct task_struct *);
37extern void __delayacct_blkio_start(void);
38extern void __delayacct_blkio_end(void);
39extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
40extern __u64 __delayacct_blkio_ticks(struct task_struct *);
41extern void __delayacct_freepages_start(void);
42extern void __delayacct_freepages_end(void);
43
44static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
45{
46 if (p->delays)
47 return (p->delays->flags & DELAYACCT_PF_BLKIO);
48 else
49 return 0;
50}
51
52static inline void delayacct_set_flag(int flag)
53{
54 if (current->delays)
55 current->delays->flags |= flag;
56}
57
58static inline void delayacct_clear_flag(int flag)
59{
60 if (current->delays)
61 current->delays->flags &= ~flag;
62}
63
64static inline void delayacct_tsk_init(struct task_struct *tsk)
65{
66 /* reinitialize in case parent's non-null pointer was dup'ed*/
67 tsk->delays = NULL;
68 if (delayacct_on)
69 __delayacct_tsk_init(tsk);
70}
71
72/* Free tsk->delays. Called from bad fork and __put_task_struct
73 * where there's no risk of tsk->delays being accessed elsewhere
74 */
75static inline void delayacct_tsk_free(struct task_struct *tsk)
76{
77 if (tsk->delays)
78 kmem_cache_free(delayacct_cache, tsk->delays);
79 tsk->delays = NULL;
80}
81
82static inline void delayacct_blkio_start(void)
83{
84 delayacct_set_flag(DELAYACCT_PF_BLKIO);
85 if (current->delays)
86 __delayacct_blkio_start();
87}
88
89static inline void delayacct_blkio_end(void)
90{
91 if (current->delays)
92 __delayacct_blkio_end();
93 delayacct_clear_flag(DELAYACCT_PF_BLKIO);
94}
95
96static inline int delayacct_add_tsk(struct taskstats *d,
97 struct task_struct *tsk)
98{
99 if (!delayacct_on || !tsk->delays)
100 return 0;
101 return __delayacct_add_tsk(d, tsk);
102}
103
104static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
105{
106 if (tsk->delays)
107 return __delayacct_blkio_ticks(tsk);
108 return 0;
109}
110
111static inline void delayacct_freepages_start(void)
112{
113 if (current->delays)
114 __delayacct_freepages_start();
115}
116
117static inline void delayacct_freepages_end(void)
118{
119 if (current->delays)
120 __delayacct_freepages_end();
121}
122
123#else
124static inline void delayacct_set_flag(int flag)
125{}
126static inline void delayacct_clear_flag(int flag)
127{}
128static inline void delayacct_init(void)
129{}
130static inline void delayacct_tsk_init(struct task_struct *tsk)
131{}
132static inline void delayacct_tsk_free(struct task_struct *tsk)
133{}
134static inline void delayacct_blkio_start(void)
135{}
136static inline void delayacct_blkio_end(void)
137{}
138static inline int delayacct_add_tsk(struct taskstats *d,
139 struct task_struct *tsk)
140{ return 0; }
141static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
142{ return 0; }
143static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
144{ return 0; }
145static inline void delayacct_freepages_start(void)
146{}
147static inline void delayacct_freepages_end(void)
148{}
149
150#endif /* CONFIG_TASK_DELAY_ACCT */
151
152#endif