LXR linux/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 <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
  32extern int delayacct_on;        /* Delay accounting turned on/off */
  33extern struct kmem_cache *delayacct_cache;
  34extern void delayacct_init(void);
  35extern void __delayacct_tsk_init(struct task_struct *);
  36extern void __delayacct_tsk_exit(struct task_struct *);
  37extern void __delayacct_blkio_start(void);
  38extern void __delayacct_blkio_end(void);
  39extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *);
  40extern __u64 __delayacct_blkio_ticks(struct task_struct *);
  41extern void __delayacct_freepages_start(void);
  42extern void __delayacct_freepages_end(void);
  43
  44static 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
  52static inline void delayacct_set_flag(int flag)
  53{
  54        if (current->delays)
  55                current->delays->flags |= flag;
  56}
  57
  58static inline void delayacct_clear_flag(int flag)
  59{
  60        if (current->delays)
  61                current->delays->flags &= ~flag;
  62}
  63
  64static 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 */
  75static 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
  82static inline void delayacct_blkio_start(void)
  83{
  84        delayacct_set_flag(DELAYACCT_PF_BLKIO);
  85        if (current->delays)
  86                __delayacct_blkio_start();
  87}
  88
  89static inline void delayacct_blkio_end(void)
  90{
  91        if (current->delays)
  92                __delayacct_blkio_end();
  93        delayacct_clear_flag(DELAYACCT_PF_BLKIO);
  94}
  95
  96static 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
 104static 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
 111static inline void delayacct_freepages_start(void)
 112{
 113        if (current->delays)
 114                __delayacct_freepages_start();
 115}
 116
 117static inline void delayacct_freepages_end(void)
 118{
 119        if (current->delays)
 120                __delayacct_freepages_end();
 121}
 122
 123#else
 124static inline void delayacct_set_flag(int flag)
 125{}
 126static inline void delayacct_clear_flag(int flag)
 127{}
 128static inline void delayacct_init(void)
 129{}
 130static inline void delayacct_tsk_init(struct task_struct *tsk)
 131{}
 132static inline void delayacct_tsk_free(struct task_struct *tsk)
 133{}
 134static inline void delayacct_blkio_start(void)
 135{}
 136static inline void delayacct_blkio_end(void)
 137{}
 138static inline int delayacct_add_tsk(struct taskstats *d,
 139                                        struct task_struct *tsk)
 140{ return 0; }
 141static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk)
 142{ return 0; }
 143static inline int delayacct_is_task_waiting_on_io(struct task_struct *p)
 144{ return 0; }
 145static inline void delayacct_freepages_start(void)
 146{}
 147static inline void delayacct_freepages_end(void)
 148{}
 149
 150#endif /* CONFIG_TASK_DELAY_ACCT */
 151
 152#endif
 153