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