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
  30 #ifdef CONFIG_TASK_DELAY_ACCT
  31
  32 extern int delayacct_on;        /* Delay accounting turned on/off */
  33 extern kmem_cache_t *delayacct_cache;
  34 extern void delayacct_init(void);
  35 extern void __delayacct_tsk_init(struct task_struct *);
  36 extern void __delayacct_tsk_exit(struct task_struct *);
  37 extern void __delayacct_blkio_start(void);
  38 extern void __delayacct_blkio_end(void);
  39 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  40 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  41
  42 static inline void delayacct_set_flag(int flag)
  43 {
  44         if (current->delays)
  45                 current->delays->flags |= flag;
  46 }
  47
  48 static inline void delayacct_clear_flag(int flag)
  49 {
  50         if (current->delays)
  51                 current->delays->flags &= ~flag;
  52 }
  53
  54 static inline void delayacct_tsk_init(struct task_struct *tsk)
  55 {
  56         /* reinitialize in case parent's non-null pointer was dup'ed*/
  57         tsk->delays = NULL;
  58         if (delayacct_on)
  59                 __delayacct_tsk_init(tsk);
  60 }
  61
  62 /* Free tsk->delays. Called from bad fork and __put_task_struct
  63  * where there's no risk of tsk->delays being accessed elsewhere
  64  */
  65 static inline void delayacct_tsk_free(struct task_struct *tsk)
  66 {
  67         if (tsk->delays)
  68                 kmem_cache_free(delayacct_cache, tsk->delays);
  69         tsk->delays = NULL;
  70 }
  71
  72 static inline void delayacct_blkio_start(void)
  73 {
  74         if (current->delays)
  75                 __delayacct_blkio_start();
  76 }
  77
  78 static inline void delayacct_blkio_end(void)
  79 {
  80         if (current->delays)
  81                 __delayacct_blkio_end();
  82 }
  83
  84 static inline int delayacct_add_tsk(struct taskstats *d,
  85                                         struct task_struct *tsk)
  86 {
  87         if (!delayacct_on || !tsk->delays)
  88                 return 0;
  89         return __delayacct_add_tsk(d, tsk);
  90 }
  91
  92 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
  93 {
  94         if (tsk->delays)
  95                 return __delayacct_blkio_ticks(tsk);
  96         return 0;
  97 }
  98
  99 #else
 100 static inline void delayacct_set_flag(int flag)
 101 {}
 102 static inline void delayacct_clear_flag(int flag)
 103 {}
 104 static inline void delayacct_init(void)
 105 {}
 106 static inline void delayacct_tsk_init(struct task_struct *tsk)
 107 {}
 108 static inline void delayacct_tsk_free(struct task_struct *tsk)
 109 {}
 110 static inline void delayacct_blkio_start(void)
 111 {}
 112 static inline void delayacct_blkio_end(void)
 113 {}
 114 static inline int delayacct_add_tsk(struct taskstats *d,
 115                                         struct task_struct *tsk)
 116 { return 0; }
 117 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 118 { return 0; }
 119 #endif /* CONFIG_TASK_DELAY_ACCT */
 120
 121 #endif