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
  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 struct task_delay_info {
  32         spinlock_t      lock;
  33         unsigned int    flags;  /* Private per-task flags */
  34
  35         /* For each stat XXX, add following, aligned appropriately
  36          *
  37          * struct timespec XXX_start, XXX_end;
  38          * u64 XXX_delay;
  39          * u32 XXX_count;
  40          *
  41          * Atomicity of updates to XXX_delay, XXX_count protected by
  42          * single lock above (split into XXX_lock if contention is an issue).
  43          */
  44
  45         /*
  46          * XXX_count is incremented on every XXX operation, the delay
  47          * associated with the operation is added to XXX_delay.
  48          * XXX_delay contains the accumulated delay time in nanoseconds.
  49          */
  50         u64 blkio_start;        /* Shared by blkio, swapin */
  51         u64 blkio_delay;        /* wait for sync block io completion */
  52         u64 swapin_delay;       /* wait for swapin block io completion */
  53         u32 blkio_count;        /* total count of the number of sync block */
  54                                 /* io operations performed */
  55         u32 swapin_count;       /* total count of the number of swapin block */
  56                                 /* io operations performed */
  57
  58         u64 freepages_start;
  59         u64 freepages_delay;    /* wait for memory reclaim */
  60         u32 freepages_count;    /* total count of memory reclaim */
  61 };
  62 #endif
  63
  64 #include <linux/sched.h>
  65 #include <linux/slab.h>
  66
  67 #ifdef CONFIG_TASK_DELAY_ACCT
  68 extern int delayacct_on;        /* Delay accounting turned on/off */
  69 extern struct kmem_cache *delayacct_cache;
  70 extern void delayacct_init(void);
  71 extern void __delayacct_tsk_init(struct task_struct *);
  72 extern void __delayacct_tsk_exit(struct task_struct *);
  73 extern void __delayacct_blkio_start(void);
  74 extern void __delayacct_blkio_end(void);
  75 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  76 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  77 extern void __delayacct_freepages_start(void);
  78 extern void __delayacct_freepages_end(void);
  79
  80 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  81 {
  82         if (p->delays)
  83                 return (p->delays->flags & DELAYACCT_PF_BLKIO);
  84         else
  85                 return 0;
  86 }
  87
  88 static inline void delayacct_set_flag(int flag)
  89 {
  90         if (current->delays)
  91                 current->delays->flags |= flag;
  92 }
  93
  94 static inline void delayacct_clear_flag(int flag)
  95 {
  96         if (current->delays)
  97                 current->delays->flags &= ~flag;
  98 }
  99
 100 static inline void delayacct_tsk_init(struct task_struct *tsk)
 101 {
 102         /* reinitialize in case parent's non-null pointer was dup'ed*/
 103         tsk->delays = NULL;
 104         if (delayacct_on)
 105                 __delayacct_tsk_init(tsk);
 106 }
 107
 108 /* Free tsk->delays. Called from bad fork and __put_task_struct
 109  * where there's no risk of tsk->delays being accessed elsewhere
 110  */
 111 static inline void delayacct_tsk_free(struct task_struct *tsk)
 112 {
 113         if (tsk->delays)
 114                 kmem_cache_free(delayacct_cache, tsk->delays);
 115         tsk->delays = NULL;
 116 }
 117
 118 static inline void delayacct_blkio_start(void)
 119 {
 120         delayacct_set_flag(DELAYACCT_PF_BLKIO);
 121         if (current->delays)
 122                 __delayacct_blkio_start();
 123 }
 124
 125 static inline void delayacct_blkio_end(void)
 126 {
 127         if (current->delays)
 128                 __delayacct_blkio_end();
 129         delayacct_clear_flag(DELAYACCT_PF_BLKIO);
 130 }
 131
 132 static inline int delayacct_add_tsk(struct taskstats *d,
 133                                         struct task_struct *tsk)
 134 {
 135         if (!delayacct_on || !tsk->delays)
 136                 return 0;
 137         return __delayacct_add_tsk(d, tsk);
 138 }
 139
 140 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 141 {
 142         if (tsk->delays)
 143                 return __delayacct_blkio_ticks(tsk);
 144         return 0;
 145 }
 146
 147 static inline void delayacct_freepages_start(void)
 148 {
 149         if (current->delays)
 150                 __delayacct_freepages_start();
 151 }
 152
 153 static inline void delayacct_freepages_end(void)
 154 {
 155         if (current->delays)
 156                 __delayacct_freepages_end();
 157 }
 158
 159 #else
 160 static inline void delayacct_set_flag(int flag)
 161 {}
 162 static inline void delayacct_clear_flag(int flag)
 163 {}
 164 static inline void delayacct_init(void)
 165 {}
 166 static inline void delayacct_tsk_init(struct task_struct *tsk)
 167 {}
 168 static inline void delayacct_tsk_free(struct task_struct *tsk)
 169 {}
 170 static inline void delayacct_blkio_start(void)
 171 {}
 172 static inline void delayacct_blkio_end(void)
 173 {}
 174 static inline int delayacct_add_tsk(struct taskstats *d,
 175                                         struct task_struct *tsk)
 176 { return 0; }
 177 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 178 { return 0; }
 179 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
 180 { return 0; }
 181 static inline void delayacct_freepages_start(void)
 182 {}
 183 static inline void delayacct_freepages_end(void)
 184 {}
 185
 186 #endif /* CONFIG_TASK_DELAY_ACCT */
 187
 188 #endif