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