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 32 extern int delayacct_on; /* Delay accounting turned on/off */ 33 extern struct kmem_cache *delayacct_cache; 34 extern void delayacct_init(void); 35 extern void __delayacct_tsk_init(struct task_struct *); 36 extern void __delayacct_tsk_exit(struct task_struct *); 37 extern void __delayacct_blkio_start(void); 38 extern void __delayacct_blkio_end(void); 39 extern int __delayacct_add_tsk(struct taskstats *, struct task_struct *); 40 extern __u64 __delayacct_blkio_ticks(struct task_struct *); 41 extern void __delayacct_freepages_start(void); 42 extern void __delayacct_freepages_end(void); 43 44 static 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 52 static inline void delayacct_set_flag(int flag) 53 { 54 if (current->delays) 55 current->delays->flags |= flag; 56 } 57 58 static inline void delayacct_clear_flag(int flag) 59 { 60 if (current->delays) 61 current->delays->flags &= ~flag; 62 } 63 64 static 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 */ 75 static 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 82 static inline void delayacct_blkio_start(void) 83 { 84 delayacct_set_flag(DELAYACCT_PF_BLKIO); 85 if (current->delays) 86 __delayacct_blkio_start(); 87 } 88 89 static inline void delayacct_blkio_end(void) 90 { 91 if (current->delays) 92 __delayacct_blkio_end(); 93 delayacct_clear_flag(DELAYACCT_PF_BLKIO); 94 } 95 96 static 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 } 103 104 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 105 { 106 if (tsk->delays) 107 return __delayacct_blkio_ticks(tsk); 108 return 0; 109 } 110 111 static inline void delayacct_freepages_start(void) 112 { 113 if (current->delays) 114 __delayacct_freepages_start(); 115 } 116 117 static inline void delayacct_freepages_end(void) 118 { 119 if (current->delays) 120 __delayacct_freepages_end(); 121 } 122 123 #else 124 static inline void delayacct_set_flag(int flag) 125 {} 126 static inline void delayacct_clear_flag(int flag) 127 {} 128 static inline void delayacct_init(void) 129 {} 130 static inline void delayacct_tsk_init(struct task_struct *tsk) 131 {} 132 static inline void delayacct_tsk_free(struct task_struct *tsk) 133 {} 134 static inline void delayacct_blkio_start(void) 135 {} 136 static inline void delayacct_blkio_end(void) 137 {} 138 static inline int delayacct_add_tsk(struct taskstats *d, 139 struct task_struct *tsk) 140 { return 0; } 141 static inline __u64 delayacct_blkio_ticks(struct task_struct *tsk) 142 { return 0; } 143 static inline int delayacct_is_task_waiting_on_io(struct task_struct *p) 144 { return 0; } 145 static inline void delayacct_freepages_start(void) 146 {} 147 static inline void delayacct_freepages_end(void) 148 {} 149 150 #endif /* CONFIG_TASK_DELAY_ACCT */ 151 152 #endif 153