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 <uapi/linux/taskstats.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
31struct task_delay_info {
32 raw_spinlock_t lock;
33 unsigned int flags; /* Private per-task flags */
34
35 /* For each stat XXX, add following, aligned appropriately
36 *
37 * struct timespec XXX_start, XXX_end;
38 * u64 XXX_delay;
39 * u32 XXX_count;
40 *
41 * Atomicity of updates to XXX_delay, XXX_count protected by
42 * single lock above (split into XXX_lock if contention is an issue).
43 */
44
45 /*
46 * XXX_count is incremented on every XXX operation, the delay
47 * associated with the operation is added to XXX_delay.
48 * XXX_delay contains the accumulated delay time in nanoseconds.
49 */
50 u64 blkio_start; /* Shared by blkio, swapin */
51 u64 blkio_delay; /* wait for sync block io completion */
52 u64 swapin_delay; /* wait for swapin block io completion */
53 u32 blkio_count; /* total count of the number of sync block */
54 /* io operations performed */
55 u32 swapin_count; /* total count of the number of swapin block */
56 /* io operations performed */
57
58 u64 freepages_start;
59 u64 freepages_delay; /* wait for memory reclaim */
60 u32 freepages_count; /* total count of memory reclaim */
61};
62#endif
63
64#include <linux/sched.h>
65#include <linux/slab.h>
66
67#ifdef CONFIG_TASK_DELAY_ACCT
68extern int delayacct_on; /* Delay accounting turned on/off */
69extern struct kmem_cache *delayacct_cache;
70extern void delayacct_init(void);
71extern void __delayacct_tsk_init(struct task_struct *);
72extern void __delayacct_tsk_exit(struct task_struct *);
73extern void __delayacct_blkio_start(void);
74extern void __delayacct_blkio_end(struct task_struct *);
75extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
76extern __u64 __delayacct_blkio_ticks(struct task_struct *);
77extern void __delayacct_freepages_start(void);
78extern void __delayacct_freepages_end(void);
79
80static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
81{
82 if (p->delays)
83 return (p->delays->flags & DELAYACCT_PF_BLKIO);
84 else
85 return 0;
86}
87
88static inline void delayacct_set_flag(int flag)
89{
90 if (current->delays)
91 current->delays->flags |= flag;
92}
93
94static inline void delayacct_clear_flag(int flag)
95{
96 if (current->delays)
97 current->delays->flags &= ~flag;
98}
99
100static inline void delayacct_tsk_init(struct task_struct *tsk)
101{
102 /* reinitialize in case parent's non-null pointer was dup'ed*/
103 tsk->delays = NULL;
104 if (delayacct_on)
105 __delayacct_tsk_init(tsk);
106}
107
108/* Free tsk->delays. Called from bad fork and __put_task_struct
109 * where there's no risk of tsk->delays being accessed elsewhere
110 */
111static inline void delayacct_tsk_free(struct task_struct *tsk)
112{
113 if (tsk->delays)
114 kmem_cache_free(delayacct_cache, tsk->delays);
115 tsk->delays = NULL;
116}
117
118static inline void delayacct_blkio_start(void)
119{
120 delayacct_set_flag(DELAYACCT_PF_BLKIO);
121 if (current->delays)
122 __delayacct_blkio_start();
123}
124
125static inline void delayacct_blkio_end(struct task_struct *p)
126{
127 if (p->delays)
128 __delayacct_blkio_end(p);
129 delayacct_clear_flag(DELAYACCT_PF_BLKIO);
130}
131
132static inline int delayacct_add_tsk(struct taskstats *d,
133 struct task_struct *tsk)
134{
135 if (!delayacct_on || !tsk->delays)
136 return 0;
137 return __delayacct_add_tsk(d, tsk);
138}
139
140static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
141{
142 if (tsk->delays)
143 return __delayacct_blkio_ticks(tsk);
144 return 0;
145}
146
147static inline void delayacct_freepages_start(void)
148{
149 if (current->delays)
150 __delayacct_freepages_start();
151}
152
153static inline void delayacct_freepages_end(void)
154{
155 if (current->delays)
156 __delayacct_freepages_end();
157}
158
159#else
160static inline void delayacct_set_flag(int flag)
161{}
162static inline void delayacct_clear_flag(int flag)
163{}
164static inline void delayacct_init(void)
165{}
166static inline void delayacct_tsk_init(struct task_struct *tsk)
167{}
168static inline void delayacct_tsk_free(struct task_struct *tsk)
169{}
170static inline void delayacct_blkio_start(void)
171{}
172static inline void delayacct_blkio_end(struct task_struct *p)
173{}
174static inline int delayacct_add_tsk(struct taskstats *d,
175 struct task_struct *tsk)
176{ return 0; }
177static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
178{ return 0; }
179static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
180{ return 0; }
181static inline void delayacct_freepages_start(void)
182{}
183static inline void delayacct_freepages_end(void)
184{}
185
186#endif /* CONFIG_TASK_DELAY_ACCT */
187
188#endif
189