mm: workingset: tell cache transitions from workingset thrashing
[muen/linux.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 <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
31 struct 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
68 extern int delayacct_on;        /* Delay accounting turned on/off */
69 extern struct kmem_cache *delayacct_cache;
70 extern void delayacct_init(void);
71 extern void __delayacct_tsk_init(struct task_struct *);
72 extern void __delayacct_tsk_exit(struct task_struct *);
73 extern void __delayacct_blkio_start(void);
74 extern void __delayacct_blkio_end(struct task_struct *);
75 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
76 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
77 extern void __delayacct_freepages_start(void);
78 extern void __delayacct_freepages_end(void);
79
80 static 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
88 static inline void delayacct_set_flag(int flag)
89 {
90         if (current->delays)
91                 current->delays->flags |= flag;
92 }
93
94 static inline void delayacct_clear_flag(int flag)
95 {
96         if (current->delays)
97                 current->delays->flags &= ~flag;
98 }
99
100 static 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  */
111 static 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
118 static inline void delayacct_blkio_start(void)
119 {
120         delayacct_set_flag(DELAYACCT_PF_BLKIO);
121         if (current->delays)
122                 __delayacct_blkio_start();
123 }
124
125 static 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
132 static 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
140 static 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
147 static inline void delayacct_freepages_start(void)
148 {
149         if (current->delays)
150                 __delayacct_freepages_start();
151 }
152
153 static inline void delayacct_freepages_end(void)
154 {
155         if (current->delays)
156                 __delayacct_freepages_end();
157 }
158
159 #else
160 static inline void delayacct_set_flag(int flag)
161 {}
162 static inline void delayacct_clear_flag(int flag)
163 {}
164 static inline void delayacct_init(void)
165 {}
166 static inline void delayacct_tsk_init(struct task_struct *tsk)
167 {}
168 static inline void delayacct_tsk_free(struct task_struct *tsk)
169 {}
170 static inline void delayacct_blkio_start(void)
171 {}
172 static inline void delayacct_blkio_end(struct task_struct *p)
173 {}
174 static inline int delayacct_add_tsk(struct taskstats *d,
175                                         struct task_struct *tsk)
176 { return 0; }
177 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
178 { return 0; }
179 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
180 { return 0; }
181 static inline void delayacct_freepages_start(void)
182 {}
183 static inline void delayacct_freepages_end(void)
184 {}
185
186 #endif /* CONFIG_TASK_DELAY_ACCT */
187
188 #endif