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 #include <linux/sched.h>
  22 #include <linux/slab.h>
  23
  24 /*
  25  * Per-task flags relevant to delay accounting
  26  * maintained privately to avoid exhausting similar flags in sched.h:PF_*
  27  * Used to set current->delays->flags
  28  */
  29 #define DELAYACCT_PF_SWAPIN     0x00000001      /* I am doing a swapin */
  30 #define DELAYACCT_PF_BLKIO      0x00000002      /* I am waiting on IO */
  31
  32 #ifdef CONFIG_TASK_DELAY_ACCT
  33
  34 extern int delayacct_on;        /* Delay accounting turned on/off */
  35 extern struct kmem_cache *delayacct_cache;
  36 extern void delayacct_init(void);
  37 extern void __delayacct_tsk_init(struct task_struct *);
  38 extern void __delayacct_tsk_exit(struct task_struct *);
  39 extern void __delayacct_blkio_start(void);
  40 extern void __delayacct_blkio_end(void);
  41 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  42 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  43 extern void __delayacct_freepages_start(void);
  44 extern void __delayacct_freepages_end(void);
  45
  46 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  47 {
  48         if (p->delays)
  49                 return (p->delays->flags & DELAYACCT_PF_BLKIO);
  50         else
  51                 return 0;
  52 }
  53
  54 static inline void delayacct_set_flag(int flag)
  55 {
  56         if (current->delays)
  57                 current->delays->flags |= flag;
  58 }
  59
  60 static inline void delayacct_clear_flag(int flag)
  61 {
  62         if (current->delays)
  63                 current->delays->flags &= ~flag;
  64 }
  65
  66 static inline void delayacct_tsk_init(struct task_struct *tsk)
  67 {
  68         /* reinitialize in case parent's non-null pointer was dup'ed*/
  69         tsk->delays = NULL;
  70         if (delayacct_on)
  71                 __delayacct_tsk_init(tsk);
  72 }
  73
  74 /* Free tsk->delays. Called from bad fork and __put_task_struct
  75  * where there's no risk of tsk->delays being accessed elsewhere
  76  */
  77 static inline void delayacct_tsk_free(struct task_struct *tsk)
  78 {
  79         if (tsk->delays)
  80                 kmem_cache_free(delayacct_cache, tsk->delays);
  81         tsk->delays = NULL;
  82 }
  83
  84 static inline void delayacct_blkio_start(void)
  85 {
  86         delayacct_set_flag(DELAYACCT_PF_BLKIO);
  87         if (current->delays)
  88                 __delayacct_blkio_start();
  89 }
  90
  91 static inline void delayacct_blkio_end(void)
  92 {
  93         if (current->delays)
  94                 __delayacct_blkio_end();
  95         delayacct_clear_flag(DELAYACCT_PF_BLKIO);
  96 }
  97
  98 static inline int delayacct_add_tsk(struct taskstats *d,
  99                                         struct task_struct *tsk)
 100 {
 101         if (!delayacct_on || !tsk->delays)
 102                 return 0;
 103         return __delayacct_add_tsk(d, tsk);
 104 }
 105
 106 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 107 {
 108         if (tsk->delays)
 109                 return __delayacct_blkio_ticks(tsk);
 110         return 0;
 111 }
 112
 113 static inline void delayacct_freepages_start(void)
 114 {
 115         if (current->delays)
 116                 __delayacct_freepages_start();
 117 }
 118
 119 static inline void delayacct_freepages_end(void)
 120 {
 121         if (current->delays)
 122                 __delayacct_freepages_end();
 123 }
 124
 125 #else
 126 static inline void delayacct_set_flag(int flag)
 127 {}
 128 static inline void delayacct_clear_flag(int flag)
 129 {}
 130 static inline void delayacct_init(void)
 131 {}
 132 static inline void delayacct_tsk_init(struct task_struct *tsk)
 133 {}
 134 static inline void delayacct_tsk_free(struct task_struct *tsk)
 135 {}
 136 static inline void delayacct_blkio_start(void)
 137 {}
 138 static inline void delayacct_blkio_end(void)
 139 {}
 140 static inline int delayacct_add_tsk(struct taskstats *d,
 141                                         struct task_struct *tsk)
 142 { return 0; }
 143 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 144 { return 0; }
 145 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
 146 { return 0; }
 147 static inline void delayacct_freepages_start(void)
 148 {}
 149 static inline void delayacct_freepages_end(void)
 150 {}
 151
 152 #endif /* CONFIG_TASK_DELAY_ACCT */
 153
 154 #endif