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