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 #include <linux/taskstats_kern.h> 22 23 /* 24 * Per-task flags relevant to delay accounting 25 * maintained privately to avoid exhausting similar flags in sched.h:PF_* 26 * Used to set current->delays->flags 27 */ 28 #define DELAYACCT_PF_SWAPIN 0x00000001 /* I am doing a swapin */ 29 #define DELAYACCT_PF_BLKIO 0x00000002 /* I am waiting on IO */ 30 31 #ifdef CONFIG_TASK_DELAY_ACCT 32 33 extern int delayacct_on; /* Delay accounting turned on/off */ 34 extern struct kmem_cache *delayacct_cache; 35 extern void delayacct_init(void); 36 extern void __delayacct_tsk_init(struct task_struct *); 37 extern void __delayacct_tsk_exit(struct task_struct *); 38 extern void __delayacct_blkio_start(void); 39 extern void __delayacct_blkio_end(void); 40 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *); 41 extern __u64 __delayacct_blkio_ticks(struct task_struct *); 42 43 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) 44 { 45 if (p->delays) 46 return (p->delays->flags & DELAYACCT_PF_BLKIO); 47 else 48 return 0; 49 } 50 51 static inline void delayacct_set_flag(int flag) 52 { 53 if (current->delays) 54 current->delays->flags |= flag; 55 } 56 57 static inline void delayacct_clear_flag(int flag) 58 { 59 if (current->delays) 60 current->delays->flags &= ~flag; 61 } 62 63 static inline void delayacct_tsk_init(struct task_struct *tsk) 64 { 65 /* reinitialize in case parent's non-null pointer was dup'ed*/ 66 tsk->delays = NULL; 67 if (delayacct_on) 68 __delayacct_tsk_init(tsk); 69 } 70 71 /* Free tsk->delays. Called from bad fork and __put_task_struct 72 * where there's no risk of tsk->delays being accessed elsewhere 73 */ 74 static inline void delayacct_tsk_free(struct task_struct *tsk) 75 { 76 if (tsk->delays) 77 kmem_cache_free(delayacct_cache, tsk->delays); 78 tsk->delays = NULL; 79 } 80 81 static inline void delayacct_blkio_start(void) 82 { 83 delayacct_set_flag(DELAYACCT_PF_BLKIO); 84 if (current->delays) 85 __delayacct_blkio_start(); 86 } 87 88 static inline void delayacct_blkio_end(void) 89 { 90 if (current->delays) 91 __delayacct_blkio_end(); 92 delayacct_clear_flag(DELAYACCT_PF_BLKIO); 93 } 94 95 static inline int delayacct_add_tsk(struct taskstats *d, 96 struct task_struct *tsk) 97 { 98 if (!delayacct_on || !tsk->delays) 99 return 0; 100 return __delayacct_add_tsk(d, tsk); 101 } 102 103 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 104 { 105 if (tsk->delays) 106 return __delayacct_blkio_ticks(tsk); 107 return 0; 108 } 109 110 #else 111 static inline void delayacct_set_flag(int flag) 112 {} 113 static inline void delayacct_clear_flag(int flag) 114 {} 115 static inline void delayacct_init(void) 116 {} 117 static inline void delayacct_tsk_init(struct task_struct *tsk) 118 {} 119 static inline void delayacct_tsk_free(struct task_struct *tsk) 120 {} 121 static inline void delayacct_blkio_start(void) 122 {} 123 static inline void delayacct_blkio_end(void) 124 {} 125 static inline int delayacct_add_tsk(struct taskstats *d, 126 struct task_struct *tsk) 127 { return 0; } 128 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 129 { return 0; } 130 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) 131 { return 0; } 132 #endif /* CONFIG_TASK_DELAY_ACCT */ 133 134 #endif 135