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         raw_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
  61         u64 thrashing_start;
  62         u64 thrashing_delay;    /* wait for thrashing page */
  63
  64         u32 freepages_count;    /* total count of memory reclaim */
  65         u32 thrashing_count;    /* total count of thrash waits */
  66 };
  67 #endif
  68
  69 #include <linux/sched.h>
  70 #include <linux/slab.h>
  71
  72 #ifdef CONFIG_TASK_DELAY_ACCT
  73 extern int delayacct_on;        /* Delay accounting turned on/off */
  74 extern struct kmem_cache *delayacct_cache;
  75 extern void delayacct_init(void);
  76 extern void __delayacct_tsk_init(struct task_struct *);
  77 extern void __delayacct_tsk_exit(struct task_struct *);
  78 extern void __delayacct_blkio_start(void);
  79 extern void __delayacct_blkio_end(struct task_struct *);
  80 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  81 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  82 extern void __delayacct_freepages_start(void);
  83 extern void __delayacct_freepages_end(void);
  84 extern void __delayacct_thrashing_start(void);
  85 extern void __delayacct_thrashing_end(void);
  86
  87 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  88 {
  89         if (p->delays)
  90                 return (p->delays->flags & DELAYACCT_PF_BLKIO);
  91         else
  92                 return 0;
  93 }
  94
  95 static inline void delayacct_set_flag(int flag)
  96 {
  97         if (current->delays)
  98                 current->delays->flags |= flag;
  99 }
 100
 101 static inline void delayacct_clear_flag(int flag)
 102 {
 103         if (current->delays)
 104                 current->delays->flags &= ~flag;
 105 }
 106
 107 static inline void delayacct_tsk_init(struct task_struct *tsk)
 108 {
 109         /* reinitialize in case parent's non-null pointer was dup'ed*/
 110         tsk->delays = NULL;
 111         if (delayacct_on)
 112                 __delayacct_tsk_init(tsk);
 113 }
 114
 115 /* Free tsk->delays. Called from bad fork and __put_task_struct
 116  * where there's no risk of tsk->delays being accessed elsewhere
 117  */
 118 static inline void delayacct_tsk_free(struct task_struct *tsk)
 119 {
 120         if (tsk->delays)
 121                 kmem_cache_free(delayacct_cache, tsk->delays);
 122         tsk->delays = NULL;
 123 }
 124
 125 static inline void delayacct_blkio_start(void)
 126 {
 127         delayacct_set_flag(DELAYACCT_PF_BLKIO);
 128         if (current->delays)
 129                 __delayacct_blkio_start();
 130 }
 131
 132 static inline void delayacct_blkio_end(struct task_struct *p)
 133 {
 134         if (p->delays)
 135                 __delayacct_blkio_end(p);
 136         delayacct_clear_flag(DELAYACCT_PF_BLKIO);
 137 }
 138
 139 static inline int delayacct_add_tsk(struct taskstats *d,
 140                                         struct task_struct *tsk)
 141 {
 142         if (!delayacct_on || !tsk->delays)
 143                 return 0;
 144         return __delayacct_add_tsk(d, tsk);
 145 }
 146
 147 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 148 {
 149         if (tsk->delays)
 150                 return __delayacct_blkio_ticks(tsk);
 151         return 0;
 152 }
 153
 154 static inline void delayacct_freepages_start(void)
 155 {
 156         if (current->delays)
 157                 __delayacct_freepages_start();
 158 }
 159
 160 static inline void delayacct_freepages_end(void)
 161 {
 162         if (current->delays)
 163                 __delayacct_freepages_end();
 164 }
 165
 166 static inline void delayacct_thrashing_start(void)
 167 {
 168         if (current->delays)
 169                 __delayacct_thrashing_start();
 170 }
 171
 172 static inline void delayacct_thrashing_end(void)
 173 {
 174         if (current->delays)
 175                 __delayacct_thrashing_end();
 176 }
 177
 178 #else
 179 static inline void delayacct_set_flag(int flag)
 180 {}
 181 static inline void delayacct_clear_flag(int flag)
 182 {}
 183 static inline void delayacct_init(void)
 184 {}
 185 static inline void delayacct_tsk_init(struct task_struct *tsk)
 186 {}
 187 static inline void delayacct_tsk_free(struct task_struct *tsk)
 188 {}
 189 static inline void delayacct_blkio_start(void)
 190 {}
 191 static inline void delayacct_blkio_end(struct task_struct *p)
 192 {}
 193 static inline int delayacct_add_tsk(struct taskstats *d,
 194                                         struct task_struct *tsk)
 195 { return 0; }
 196 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 197 { return 0; }
 198 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
 199 { return 0; }
 200 static inline void delayacct_freepages_start(void)
 201 {}
 202 static inline void delayacct_freepages_end(void)
 203 {}
 204 static inline void delayacct_thrashing_start(void)
 205 {}
 206 static inline void delayacct_thrashing_end(void)
 207 {}
 208
 209 #endif /* CONFIG_TASK_DELAY_ACCT */
 210
 211 #endif