include/linux/delayacct.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* delayacct.h - per-task delay accounting
   3  *
   4  * Copyright (C) Shailabh Nagar, IBM Corp. 2006
   5  */
   6
   7 #ifndef _LINUX_DELAYACCT_H
   8 #define _LINUX_DELAYACCT_H
   9
  10 #include <uapi/linux/taskstats.h>
  11
  12 /*
  13  * Per-task flags relevant to delay accounting
  14  * maintained privately to avoid exhausting similar flags in sched.h:PF_*
  15  * Used to set current->delays->flags
  16  */
  17 #define DELAYACCT_PF_SWAPIN     0x00000001      /* I am doing a swapin */
  18 #define DELAYACCT_PF_BLKIO      0x00000002      /* I am waiting on IO */
  19
  20 #ifdef CONFIG_TASK_DELAY_ACCT
  21 struct task_delay_info {
  22         raw_spinlock_t  lock;
  23         unsigned int    flags;  /* Private per-task flags */
  24
  25         /* For each stat XXX, add following, aligned appropriately
  26          *
  27          * struct timespec XXX_start, XXX_end;
  28          * u64 XXX_delay;
  29          * u32 XXX_count;
  30          *
  31          * Atomicity of updates to XXX_delay, XXX_count protected by
  32          * single lock above (split into XXX_lock if contention is an issue).
  33          */
  34
  35         /*
  36          * XXX_count is incremented on every XXX operation, the delay
  37          * associated with the operation is added to XXX_delay.
  38          * XXX_delay contains the accumulated delay time in nanoseconds.
  39          */
  40         u64 blkio_start;        /* Shared by blkio, swapin */
  41         u64 blkio_delay;        /* wait for sync block io completion */
  42         u64 swapin_delay;       /* wait for swapin block io completion */
  43         u32 blkio_count;        /* total count of the number of sync block */
  44                                 /* io operations performed */
  45         u32 swapin_count;       /* total count of the number of swapin block */
  46                                 /* io operations performed */
  47
  48         u64 freepages_start;
  49         u64 freepages_delay;    /* wait for memory reclaim */
  50
  51         u64 thrashing_start;
  52         u64 thrashing_delay;    /* wait for thrashing page */
  53
  54         u32 freepages_count;    /* total count of memory reclaim */
  55         u32 thrashing_count;    /* total count of thrash waits */
  56 };
  57 #endif
  58
  59 #include <linux/sched.h>
  60 #include <linux/slab.h>
  61
  62 #ifdef CONFIG_TASK_DELAY_ACCT
  63 extern int delayacct_on;        /* Delay accounting turned on/off */
  64 extern struct kmem_cache *delayacct_cache;
  65 extern void delayacct_init(void);
  66 extern void __delayacct_tsk_init(struct task_struct *);
  67 extern void __delayacct_tsk_exit(struct task_struct *);
  68 extern void __delayacct_blkio_start(void);
  69 extern void __delayacct_blkio_end(struct task_struct *);
  70 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  71 extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  72 extern void __delayacct_freepages_start(void);
  73 extern void __delayacct_freepages_end(void);
  74 extern void __delayacct_thrashing_start(void);
  75 extern void __delayacct_thrashing_end(void);
  76
  77 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
  78 {
  79         if (p->delays)
  80                 return (p->delays->flags & DELAYACCT_PF_BLKIO);
  81         else
  82                 return 0;
  83 }
  84
  85 static inline void delayacct_set_flag(int flag)
  86 {
  87         if (current->delays)
  88                 current->delays->flags |= flag;
  89 }
  90
  91 static inline void delayacct_clear_flag(int flag)
  92 {
  93         if (current->delays)
  94                 current->delays->flags &= ~flag;
  95 }
  96
  97 static inline void delayacct_tsk_init(struct task_struct *tsk)
  98 {
  99         /* reinitialize in case parent's non-null pointer was dup'ed*/
 100         tsk->delays = NULL;
 101         if (delayacct_on)
 102                 __delayacct_tsk_init(tsk);
 103 }
 104
 105 /* Free tsk->delays. Called from bad fork and __put_task_struct
 106  * where there's no risk of tsk->delays being accessed elsewhere
 107  */
 108 static inline void delayacct_tsk_free(struct task_struct *tsk)
 109 {
 110         if (tsk->delays)
 111                 kmem_cache_free(delayacct_cache, tsk->delays);
 112         tsk->delays = NULL;
 113 }
 114
 115 static inline void delayacct_blkio_start(void)
 116 {
 117         delayacct_set_flag(DELAYACCT_PF_BLKIO);
 118         if (current->delays)
 119                 __delayacct_blkio_start();
 120 }
 121
 122 static inline void delayacct_blkio_end(struct task_struct *p)
 123 {
 124         if (p->delays)
 125                 __delayacct_blkio_end(p);
 126         delayacct_clear_flag(DELAYACCT_PF_BLKIO);
 127 }
 128
 129 static inline int delayacct_add_tsk(struct taskstats *d,
 130                                         struct task_struct *tsk)
 131 {
 132         if (!delayacct_on || !tsk->delays)
 133                 return 0;
 134         return __delayacct_add_tsk(d, tsk);
 135 }
 136
 137 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 138 {
 139         if (tsk->delays)
 140                 return __delayacct_blkio_ticks(tsk);
 141         return 0;
 142 }
 143
 144 static inline void delayacct_freepages_start(void)
 145 {
 146         if (current->delays)
 147                 __delayacct_freepages_start();
 148 }
 149
 150 static inline void delayacct_freepages_end(void)
 151 {
 152         if (current->delays)
 153                 __delayacct_freepages_end();
 154 }
 155
 156 static inline void delayacct_thrashing_start(void)
 157 {
 158         if (current->delays)
 159                 __delayacct_thrashing_start();
 160 }
 161
 162 static inline void delayacct_thrashing_end(void)
 163 {
 164         if (current->delays)
 165                 __delayacct_thrashing_end();
 166 }
 167
 168 #else
 169 static inline void delayacct_set_flag(int flag)
 170 {}
 171 static inline void delayacct_clear_flag(int flag)
 172 {}
 173 static inline void delayacct_init(void)
 174 {}
 175 static inline void delayacct_tsk_init(struct task_struct *tsk)
 176 {}
 177 static inline void delayacct_tsk_free(struct task_struct *tsk)
 178 {}
 179 static inline void delayacct_blkio_start(void)
 180 {}
 181 static inline void delayacct_blkio_end(struct task_struct *p)
 182 {}
 183 static inline int delayacct_add_tsk(struct taskstats *d,
 184                                         struct task_struct *tsk)
 185 { return 0; }
 186 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 187 { return 0; }
 188 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
 189 { return 0; }
 190 static inline void delayacct_freepages_start(void)
 191 {}
 192 static inline void delayacct_freepages_end(void)
 193 {}
 194 static inline void delayacct_thrashing_start(void)
 195 {}
 196 static inline void delayacct_thrashing_end(void)
 197 {}
 198
 199 #endif /* CONFIG_TASK_DELAY_ACCT */
 200
 201 #endif