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
61 u64 thrashing_start;
62 u64 thrashing_delay; /* wait for thrashing page */
63
64 u32 freepages_count; /* total count of memory reclaim */
65 u32 thrashing_count; /* total count of thrash waits */
66};
67#endif
68
69#include <linux/sched.h>
70#include <linux/slab.h>
71
72#ifdef CONFIG_TASK_DELAY_ACCT
73extern int delayacct_on; /* Delay accounting turned on/off */
74extern struct kmem_cache *delayacct_cache;
75extern void delayacct_init(void);
76extern void __delayacct_tsk_init(struct task_struct *);
77extern void __delayacct_tsk_exit(struct task_struct *);
78extern void __delayacct_blkio_start(void);
79extern void __delayacct_blkio_end(struct task_struct *);
80extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
81extern __u64 __delayacct_blkio_ticks(struct task_struct *);
82extern void __delayacct_freepages_start(void);
83extern void __delayacct_freepages_end(void);
84extern void __delayacct_thrashing_start(void);
85extern void __delayacct_thrashing_end(void);
86
87static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
88{
89 if (p->delays)
90 return (p->delays->flags & DELAYACCT_PF_BLKIO);
91 else
92 return 0;
93}
94
95static inline void delayacct_set_flag(int flag)
96{
97 if (current->delays)
98 current->delays->flags |= flag;
99}
100
101static inline void delayacct_clear_flag(int flag)
102{
103 if (current->delays)
104 current->delays->flags &= ~flag;
105}
106
107static inline void delayacct_tsk_init(struct task_struct *tsk)
108{
109 /* reinitialize in case parent's non-null pointer was dup'ed*/
110 tsk->delays = NULL;
111 if (delayacct_on)
112 __delayacct_tsk_init(tsk);
113}
114
115/* Free tsk->delays. Called from bad fork and __put_task_struct
116 * where there's no risk of tsk->delays being accessed elsewhere
117 */
118static inline void delayacct_tsk_free(struct task_struct *tsk)
119{
120 if (tsk->delays)
121 kmem_cache_free(delayacct_cache, tsk->delays);
122 tsk->delays = NULL;
123}
124
125static inline void delayacct_blkio_start(void)
126{
127 delayacct_set_flag(DELAYACCT_PF_BLKIO);
128 if (current->delays)
129 __delayacct_blkio_start();
130}
131
132static inline void delayacct_blkio_end(struct task_struct *p)
133{
134 if (p->delays)
135 __delayacct_blkio_end(p);
136 delayacct_clear_flag(DELAYACCT_PF_BLKIO);
137}
138
139static inline int delayacct_add_tsk(struct taskstats *d,
140 struct task_struct *tsk)
141{
142 if (!delayacct_on || !tsk->delays)
143 return 0;
144 return __delayacct_add_tsk(d, tsk);
145}
146
147static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
148{
149 if (tsk->delays)
150 return __delayacct_blkio_ticks(tsk);
151 return 0;
152}
153
154static inline void delayacct_freepages_start(void)
155{
156 if (current->delays)
157 __delayacct_freepages_start();
158}
159
160static inline void delayacct_freepages_end(void)
161{
162 if (current->delays)
163 __delayacct_freepages_end();
164}
165
166static inline void delayacct_thrashing_start(void)
167{
168 if (current->delays)
169 __delayacct_thrashing_start();
170}
171
172static inline void delayacct_thrashing_end(void)
173{
174 if (current->delays)
175 __delayacct_thrashing_end();
176}
177
178#else
179static inline void delayacct_set_flag(int flag)
180{}
181static inline void delayacct_clear_flag(int flag)
182{}
183static inline void delayacct_init(void)
184{}
185static inline void delayacct_tsk_init(struct task_struct *tsk)
186{}
187static inline void delayacct_tsk_free(struct task_struct *tsk)
188{}
189static inline void delayacct_blkio_start(void)
190{}
191static inline void delayacct_blkio_end(struct task_struct *p)
192{}
193static inline int delayacct_add_tsk(struct taskstats *d,
194 struct task_struct *tsk)
195{ return 0; }
196static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
197{ return 0; }
198static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
199{ return 0; }
200static inline void delayacct_freepages_start(void)
201{}
202static inline void delayacct_freepages_end(void)
203{}
204static inline void delayacct_thrashing_start(void)
205{}
206static inline void delayacct_thrashing_end(void)
207{}
208
209#endif /* CONFIG_TASK_DELAY_ACCT */
210
211#endif
212